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Justia Patents In Array Having Structure For Use As Imager Or Display, Or With Transparent ElectrodeUS Patent for Light-emitting element and display device Patent (Patent # 10,553,657)
Light-emitting element and display device
Nov 5, 2018 - Japan Display Inc.
Provided is a light-emitting element including a first electrode, a partition wall covering an edge portion of the first electrode, a light-confining layer in contact with a side surface of the partition wall and the first electrode, an electroluminescence layer over the first electrode and in contact with the first electrode and the light-confining layer, and a second electrode over the electroluminescence layer. A refractive index of the light-confining layer is lower than a refractive index of the electroluminescence layer.
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This application is based on and claims the benefit of priority from the prior Japanese Patent Application No. 2017-228807, filed on Nov. 29, 2017, the entire contents of which are incorporated herein by reference.
An embodiment of the present invention relates to a light-emitting element, a display device including the light-emitting element, and a manufacturing method thereof.
As an example of a display device, an organic EL (Electroluminescence) display device is represented. An organic EL display device possesses an organic light-emitting element (hereinafter, referred to as a light-emitting element) in each of a plurality of pixels formed over a substrate. A light-emitting element has a layer (hereinafter, referred to as an EL layer) containing an organic compound between a pair of electrodes (cathode and anode) and is driven by supplying current to the EL layer from the pair of electrodes.
Efficiency and emission color of a light-emitting element are controlled by a structure of the EL layer and an emission material included in the EL layer. For example, appropriate selection of an emission material enables light emission with a variety of colors. Additionally, it is also possible to adjust an emission wavelength and increase emission intensity in a front direction by utilizing light-interference effects in or outside the light-emitting element. Japanese Patent Application Publications No. 2017-112011, 2017-62902, and 2017-107181 disclose that a resonance structure is formed in a light-emitting element to allow light emission obtained from an emission layer to resonate, thereby adjusting emission intensity and emission color.
An embodiment of the present invention is a light-emitting element. The light-emitting element includes: a first electrode; a partition wall covering an edge portion of the first electrode; a light-confining layer in contact with a side surface of the partition wall and the first electrode; an electroluminescence layer over the first electrode and in contact with the first electrode and the light-confining layer; and a second electrode over the electroluminescence layer. A refractive index of the light-confining layer is lower than a refractive index of the electroluminescence layer.
An embodiment of the present invention is a display device. The display device includes: a first light-emitting element; a second light-emitting element adjacent to the first light-emitting element; and a partition wall between the first light-emitting element and the second light-emitting element. The first light-emitting element and the second light-emitting element each possess: a first electrode having an edge portion covered by the partition wall; a light-confining layer in contact with a side surface of the partition wall and the first electrode; an electroluminescence layer over the first electrode and in contact with the first electrode and the light-confining layer; and a second electrode over the electroluminescence layer. A refractive index of the light-confining layer is lower than a refractive index of the electroluminescence layer in each of the first light-emitting element and the second light-emitting element.
An embodiment of the present invention is a light-emitting element. The light-emitting element includes: a first electrode; a partition wall covering an edge portion of the first electrode; a first light-confining layer covering at least a part of a side surface of the partition wall; a second light-confining layer between and in contact with the first light-confining layer and the partition wall; an electroluminescence layer over the first electrode and in contact with the first electrode and the first light-confining layer; and a second electrode over the electroluminescence layer. A refractive index of the second light-confining layer is lower than a refractive index of the electroluminescence layer and a refractive index of the first light-confining layer.
An embodiment of the present invention is a display device. The display device includes: a first light-emitting element; a second light-emitting element adjacent to the first light-emitting element; and a partition wall between the first light-emitting element and the second light-emitting element. The first light-emitting element and the second light-emitting element each possess: a first electrode having an edge portion covered by the partition wall; a first light-confining layer covering at least a part of a side surface of the partition wall; a second light-confining layer between and in contact with the first light-confining layer and the partition wall; an electroluminescence layer over the first electrode and in contact with the first electrode and the first light-confining layer; and a second electrode over the electroluminescence layer. A refractive index of the second light-confining layer is lower than a refractive index of the electroluminescence layer and a refractive index of the first light-confining layer.
FIG. 1A and FIG. 1B are respectively a schematic top view and cross-sectional view of a light-emitting element according to an embodiment of the present invention;
FIG. 2A and FIG. 2B are schematic cross-sectional views of a light-emitting element according to an embodiment of the present invention;
FIG. 3A to FIG. 3C are schematic cross-sectional views of a light-emitting element according to an embodiment of the present invention;
FIG. 6 is a schematic top view of a display device according to an embodiment of the present invention;
FIG. 7 is an example of an equivalent circuit of a pixel of a display device according to an embodiment of the present invention;
FIG. 8 is a schematic cross-sectional view of a display device according to an embodiment of the present invention;
FIG. 9A and FIG. 9B are schematic cross-sectional views explaining a manufacturing method of a display device according to an embodiment of the present invention;
FIG. 10A and FIG. 10B are schematic cross-sectional views explaining a manufacturing method of a display device according to an embodiment of the present invention; and
FIG. 11A and FIG. 11B are schematic cross-sectional views explaining a manufacturing method of a display device according to an embodiment of the present invention.
DESCRIPTION OF EMBODIMENTS
Hereinafter, the embodiments of the present invention are explained with reference to the drawings. The invention can be implemented in a variety of different modes within its concept and should not be interpreted only within the disclosure of the embodiments exemplified below.
The drawings may be illustrated so that the width, thickness, shape, and the like are illustrated more schematically compared with those of the actual modes in order to provide a clearer explanation. However, they are only an example, and do not limit the interpretation of the invention. In the specification and the drawings, the same reference number is provided to an element that is the same as that which appears in preceding drawings, and a detailed explanation may be omitted as appropriate.
In the present specification and claims, when a plurality of films is formed by processing one film, the plurality of films may have functions or rules different from each other. However, the plurality of films originates from a film formed as the same layer in the same process and has the same layer structure and the same material. Therefore, the plurality of films is defined as films existing in the same layer.
In the specification and the claims, unless specifically stated, when a state is expressed where a structure is arranged "over" another structure, such an expression includes both a case where the substrate is arranged immediately above the "other structure" so as to be in contact with the "other structure" and a case where the structure is arranged over the "other structure" with an additional structure therebetween.
First Embodiment 1. Basic Structure
Schematic top and cross-sectional views of a light-emitting element 100 according to an embodiment of the present invention are respectively shown in FIG. 1A and FIG. 1B. One light-emitting element 100 and a part of the light-emitting element 100 adjacent thereto are shown in FIG. 1A and FIG. 1B, and a schematic view of a cross section along a chain line A-A′ of FIG. 1A is FIG. 1B. A second electrode 110, an electroluminescence layer (hereinafter, referred to as an EL layer) 108, and a part of a light-confining layer 106 described below are not illustrated in FIG. 1A for visibility. As shown in FIG. 1B, the light-emitting element 100 possesses a first electrode 102, a partition wall 104, the light-confining layer 106, the EL layer 108, and the second electrode 110.
The first electrode 102 has a function to inject carriers (holes and electrons) to the EL layer 108 and reflect light emission obtained from the EL layer 108. The first electrode 102 functions as an anode or a cathode. Hereinafter, the light-emitting element 100 is explained by using an example where the first electrode 102 and the second electrode 110 respectively function as an anode and a cathode. Although a structure of the first electrode 102 can be arbitrarily selected, it is preferred that a work function of a surface thereof be high to efficiently inject holes to the EL layer 108. Moreover, the first electrode 102 preferably exhibits a high reflectance with respect to visible light in order to reflect the light emission. Therefore, it is possible to employ a stacked-layer structure of a metal with a high reflectively, such as aluminum, silver, or an alloy thereof, and a conductive oxide capable of transmitting visible light, such as indium-tin oxide (ITO) and indium-zinc oxide (IZO). For instance, a stacked-layer structure may be employed as a structure of the first electrode 102 which includes a first conductive layer 102a containing a conductive oxide, a second conductive layer 102b located over the first conductive layer 102a and containing a metal or an alloy described above, and a third conductive layer 102c located over the second conductive layer 102b and containing a conductive oxide as shown in FIG. 1B. In this structure, the high work function of the conductive oxide included in the third conductive layer 102c contributes to the hole injection. In addition, a top surface of the second conductive layer 102b serves as a reflective surface at which the light emission obtained in the EL layer 108 is reflected.
The partition wall 104 is an insulating film including a resin such as an epoxy resin, an acrylic resin, a polysiloxane resin, or a polyester resin, in contact with the first electrode 102, and covers an edge portion thereof (FIG. 1A and FIG. 1B). In other words, the partition wall 104 possesses a plurality of openings, and the first electrode 102 is exposed in the openings. A slope of a side surface of the partition wall 104 is preferred to be relatively steep. For example, an angle θ between the side surface of the partition wall 104 and a bottom surface of the partition wall 104 in contact with the first electrode 102 (see FIG. 1B) may be equal to or more than 60° and less than 90°, equal to or more than 70° and less than 90°, or equal to or more than 80° and less than 90°. The partition wall 104 is configured to be optically uniform. That is, the refractive index is substantially uniform in the whole of the partition wall 104, and no light-scattering structure (microparticles, holes, and the like) is included.
The light-confining layer 106 is an insulating film, in contact with the side surface of the partition wall, and covers at least a part of the side surface. An example is demonstrated in FIG. 1B in which the light-confining layer 106 is formed to cover the side surface and a top surface of the partition wall 104. In this case, the light-confining layer 106 is shared by the adjacent light-emitting elements 100 and disposed so as to extend from one of the light-emitting elements 100 to the adjacent light-emitting element 100. The light-confining layer 106 may be configured so that a permittivity thereof is smaller than that of the EL layer 108. For example, the light-confining layer 106 may be formed so that a difference in permittivity between the light-confining layer 106 and the EL layer 108 is equal to or more than 0.2 F/m or equal to or more than 0.3 F/m. More specifically, the permittivity of the light-confining layer 106 may be equal to or more than 3.0 F/m and equal to or less than 5.0 F/m or equal to or more than 3.0 F/m and equal to or less than 4.0 F/m. Alternatively, in view of the proportional relationship between a square of a refractive index and a permittivity of a substrate, the light-confining layer 106 may be configured so that a refractive index of the light-confining layer 106 is smaller than a refractive index of the EL layer 108. For example, the light-confining layer 106 is formed so that a difference in a refractive index between the light-confining layer 106 and the EL layer 108 is equal to or more than 0.2 or equal to or more than 0.3. More specifically, the refractive index of the light-confining layer 106 may be equal to or more than 1.4 and equal to or less than 1.6 or equal to or more than 1.4 and equal to or less than 1.5. As such a material, a polymer exemplified by a polyimide or an acrylic resin is represented. When the light-confining layer 106 and the partition wall 104 each include an acrylic resin, the materials thereof are selected so that the permittivity and the refractive index of the former is smaller than those of the latter.
Alternatively, the light-confining layer 106 may include a fluorine-containing polymer as a material having a low refractive index. As such a polymer, polytetrafluoroethylene, poly(vinylidene fluoride), a derivative thereof as well as a poly(vinyl ether), a polyimide, a poly(methacrylic ester), a poly(acrylic ester), and a polysiloxane having fluorine in a main or side chain are represented, for example. These polymers may be intramolecularly or intermolecularly cross-linked.
Alternatively, the light-confining layer 106 may contain an inorganic compound such as a metal fluoride exemplified by lithium fluoride, magnesium fluoride, and calcium fluoride or silicon oxide including boron oxide or phosphorus oxide as a material with a relatively low refractive index.
The light-confining layer 106 may be configured to have a thickness in a direction parallel to the surface of the first electrode 102, that is, a width W of a surface in contact with the first electrode 102 (see FIG. 1A and FIG. 1B), which is equal to or more than 50 nm and equal to or less than 200 nm. Alternatively, the light-confining layer 106 may be configured so that the width W is equal to or less than one fourth of a wavelength λ of the emission from the EL layer 108, that is, W≤λ/4 is satisfied. In other words, the light-confining layer 106 can be configured so that the width W is equal to or larger than 50 nm and equal to or smaller than λ/4. Here, the emission wavelength is a peak wavelength of the emission obtained from the light-emitting element 100 or an emission peak wavelength of an emission material included in the EL layer 108 described below.
The EL layer 108 is disposed over the first electrode 102 so as to be in contact with the first electrode 102 and the light-confining layer 106. In the example demonstrated in FIG. 1B, the EL layer 108 is located over the light-confining layer 106 and in contact with a side surface and a top surface of the light-confining layer 106. In the specification and the claims, the EL layer 108 means the film sandwiched by the first electrode 102 and the second electrode 110.
The structure of the EL layer 108 is arbitrarily determined, and the EL layer 108 is structured by appropriately combining functional layers such as a hole-injection layer, a hole-transporting layer, an emission layer, an electron-transporting layer, an electron-injection layer, a hole-blocking layer, an electron-blocking layer, an exciton-blocking layer, and a charge-generation layer. One functional layer may have a plurality of functions. For example, an emission layer including an emission material may also serve as an electron-transporting layer or a hole-transporting layer. In addition, each layer may be formed with a single material or a stack of different materials. The structure of the EL layer 108 may be the same or different between the adjacent light-emitting elements 100. For example, the plurality of light-emitting elements 100 may be configured so that a material included in an emission layer is different between the adjacent light-emitting elements 100. In this case, different emission colors can be obtained from the adjacent light-emitting elements 100. In the example demonstrated in FIG. 1B, three layers involving a hole-transporting layer 108a, an emission layer 108b, and an electron-transporting layer 108c are illustrated as the typical functional layers. Here, when the EL layer 108 is structured with a plurality of functional layers, the permittivity and the refractive index of the EL layer 108 mean those of the entire EL layer 108.
The second electrode 110 is disposed over and in contact with the EL layer 108. The second electrode 110 is configured as a semi-transparent, semi-reflective electrode partly reflecting and partly transmitting visible light and is preferred to have a relatively low work function in order to efficiently inject electrons to the EL layer 108. For instance, the second electrode 110 may include magnesium, lithium, silver, or an alloy thereof (e.g., Mg—Ag) and may be formed at a thickness which allows visible light to partly pass therethrough. A specific thickness is selected from a range from 5 nm to 100 nm. A layer including a conductive oxide capable of transmitting visible light, such as ITO and IZO, may be further stacked over a film including the metal described above.
A potential difference provided between the first electrode 102 and the second electrode 110 enables injection of holes and electrons to the EL layers 108 from the former and the latter, respectively. The holes are transported to the emission layer 108b through the hole-transporting layer 108a, while the electrons are transported to the emission layer 108b through the electron-transporting layer 108c. Recombination of the hole and electron in the emission layer 108b results in an excited state of an emission material included in the emission layer 108b. When the excited state relaxes to a ground state, light of a wavelength corresponding to an energy difference between the excited state and the ground state is radiated and is observed as the light emission from the light-emitting element 100.
2. Optical Adjustment
In the light-emitting element 100, a vertical-mode resonance structure and a lateral-mode resonance structure are formed as explained below.
2-1. Vertical-Mode Resonance Structure
An enlarged cross-sectional view of a part of the light-emitting element 100 is shown in FIG. 2A. As described above, the first electrode 102 is configured to reflect visible light, and the second electrode 110 is configured to partly transmit and partly reflect visible light. Hence, the light emitted from the emission layer 108b is reflected at the reflective surface of the first electrode 102 and a bottom surface of the second electrode 110 and resonates. Namely, a resonance structure is constructed by the reflective surface of the first electrode 102 and the bottom surface of the second electrode 110. The interference effect attainable by this resonance is determined by an optical distance L between the reflective surface of the first electrode 102 and the bottom surface of the second electrode 110 and a spectrum of the emission from the emission layer 108b. In the case where the reflective surface is a top surface of the first electrode 102, the optical distance L is a sum of the products of the refractive indexes and the thicknesses of each functional layer in the EL layer 108. As described above, the reflective surface is the top surface of the second conductive layer 102b in the example demonstrated n FIG. 2A. In this case, the optical length L is a sum of the products of the refractive indexes and the thickness of each functional layer in the EL layer 108 and the product of the refractive index and the thickness of the third conductive layer 102c. The structure and materials in the EL layer 108 and the material and the thickness of the third conductive layer 102c are appropriately selected and adjusted so that the optical length L is consistent with an odd multiple of one fourth of the wavelength of the emission (λ/4) obtained from the EL layer 108. When the optical length L is adjusted in such a way, the light having a wavelength consistent with the optical length L is repeatedly reflected between the reflective surface of the first electrode 102 and the bottom surface of the second electrode 110 to be amplified by the interference effect, while the light having a wavelength inconsistent with the optical length L is attenuated. Accordingly, a half-width half maximum of the light emission obtained from the light-emitting element 100 is decreased, color purity is improved, and the luminance of the light-emitting element 100 in the front direction, i.e., emission efficiency, is increased.
2-2. Lateral-Mode Resonance Structure
An enlarged view of a part of the cross section of the light-emitting element 100 is shown in FIG. 2B. Here, the El layer 108 and the second electrode 110 are omitted for visibility. Although the light emitted in a vertical direction from the emission layer 108 (that is, a normal direction of the top surface of the first electrode 102 or a direction in an angle close thereto) is amplified in the vertical-mode resonance structure described above, the light emitted in a lateral direction (a direction parallel to the top surface of the first electrode 102 or a direction in an angle close thereto) cannot be efficiently extracted.
However, the light-confining layer 106 is provided in the light-emitting element 100 as described above. The light-confining layer 106 and the EL layer 108 are different in refractive index and permittivity from each other, and the refractive index and permittivity of the former are smaller than those of the latter. Therefore, the light obtained from the emission layer 108b is reflected at an interface between the EL layer 108 and the light-confining layer 106. Additionally, the width W of the light-confining layer 106 is adjusted to be equal to or more than 50 nm and equal to or less than 200 nm or equal to or more than 50 nm and equal to or less than λ/4 as described above. Hence, the light emitted from the light-emitting layer 108b is effectively prevented from leaking to the partition wall 104. As a result, loss of light in a lateral direction is small even if the light is repeatedly reflected between the interfaces between the EL layer 108 and the light-confining layer 106. Here, the side surface of the partition wall 104 is inclined from the top surface of the first electrode 102, which causes the interface between the EL layer 108 and the light-confining layer 106 to be included from the top surface of the first electrode 102. Therefore, the direction of the light gradually varies to the lateral direction while repeating the reflection at this interface and is extracted to the outside of the light-emitting element 100 when the direction exceeds a critical angle of the second electrode 110. Such a mechanism (reflection structure) enables the light obtained from the emission layer 108b to be efficiently extracted, allowing production of a light-emitting element exhibiting high emission efficiency.
Note that a width of the partition wall 104, the angle θ of the side surface of the partition wall 104, the area of the first electrode 102 may be adjusted so that the optical length between the opposing interfaces between the EL layer 108 and the light-confining layer 106 is consistent with an odd multiple of λ/4. With this structure, the emitted light is amplified by the light-interference effect even in the lateral direction, by which the half-width half maximum of the light emission obtained from the light-emitting element 100 is decreased, color purity is improved, and the luminance in the front direction, i.e., emission efficiency, is increased.
3. Modified Example
The structure of the light-emitting element 100 is not limited to the structure described above. For example, the light-confining layer 106 may not be in contact with at least a part of a top surface of the partition wall 104 and may be spaced apart from the light-confining layer 106 of the adjacent light-emitting element 100 as shown in FIG. 3A. In this case, the light-confining layer 106 covers at least a part of the side surface of the partition wall 104, and the EL layer 108 is in contact with the top surface of the partition wall 104. Alternatively, The EL layer 108 may be separated between the adjacent light-emitting elements 100 as shown in FIG. 3B. In this case, the second electrode 110 may be in contact with the partition wall 104 and the light-confining layer 106, and a top surface of the EL layer 108, the top surface of the partition wall 104, and a top surface of the light-confining layer 106 may exist in the same plane. Furthermore, a top surface of the EL layer 108, the top surface of the partition wall 104, and a top surface of the light-confining layer 106 may exist in the same layer as shown in FIG. 3C.
In the light-emitting element 100 according to the present embodiment, not only the light emitted from the emission layer 108b in the vertical direction resonates in a vertical mode to be amplified, but also the light emitted in the lateral direction repeats reflection without being attenuated and is finally extracted from the light-emitting element 100 as described above. Hence, the light-emitting element 100 shows high light-extraction efficiency. In addition, the light-emitting element 100 is able to provide light with high color purity at high efficiency mainly due to the resonance structure in the vertical mode.
Second Embodiment
In the present embodiment, a light-emitting element 120 different in structure from the light-emitting element 100 is explained. An explanation of the structure the same as or similar to that of the First Embodiment may be omitted.
A schematic cross-sectional view of the light-emitting element 120 is shown in FIG. 4A. This cross-sectional view corresponds to the cross section in FIG. 1B. As demonstrated in FIG. 4A, the light-emitting element 120 is different from the light-emitting element 100 in that it has two stacked light-confining layers. More specifically, the light-emitting element 120 is different from the light-emitting element in that it has a first light-confining layer 122 covering at least a part of the side surface of the partition wall 104 and a second light-confining layer 124 in contact with and sandwiched by the first light-confining layer 122 and the partition wall 104.
The first light-confining layer 122 is configured so that a permittivity thereof is the same as or close to that of the EL layer 108. Specifically, the light-confining layer 122 is provided so that a difference in permittivity between the light-confining layer 122 and the EL layer 108 is less than 0.2 F/m. Alternatively, the first light-confining layer 122 is configured so that a refractive index thereof is the same as or close to that of the EL layer 108. Specifically, the refractive index of the first light-confining layer 122 is more than 1.6 and less than 1.9.
On the other hand, the second light-confining layer 124 corresponds to the light-confining layer 106 of the First Embodiment, and a permittivity and a refractive index thereof are lower than those of the EL layer 108 and the first light-confining layer 122. Specifically, the permittivity of the second light-confining layer 124 may be lower than those of the EL layer 108 and the first light-confining layer 122 by 0.2 F/m or more or 0.3 F/m or more and may be specifically equal to or more than 3.0 F/m and equal to or less than 5.0 F/m or equal to or more than 3.0 F/m and equal to or less than 4.0 F/m. The refractive index of the second light-confining layer 124 may be lower than those of the EL layer 108 and the first light-confining layer 122 by 0.2 or more or 0.3 or more and may be specifically equal to or more than 1.4 and equal to or less than 1.6 or equal to or more than 1.4 and equal to or less than 1.5. As a specific material, the material usable in the light-confining layer 106 of the First Embodiment can be used for the second light-confining layer 124. Moreover, similar to the light-confining layer 106, the second light-confining layer 124 is configured so that a thickness in a direction parallel to the surface of the first electrode 102, that is, a width W2 of a surface in contact with the first electrode 102 (see FIG. 4A) is equal to or more than 50 nm and equal to or less than 200 nm or λ/4. Note that a thickness of the first light-confining layer 122 in a direction parallel to the surface of the first electrode 102, that is, a width W1 of a surface in contact with the first electrode 102 (see FIG. 4A) is adjusted so that a sum of the widths W1 and W2 is more than λ/4 and equal to or less than λ.
In the light-emitting element 120 shown in FIG. 4A, the first light-confining layer 122 and the second light-confining layer 124 are each shared by the adjacent light-emitting elements 120 and are disposed so as to extend from one light-emitting element 120 to the adjacent light-emitting element 120. However, the structure of the light-emitting element 120 is not limited thereto, and the second light-confining layer 124 may be separated between the adjacent light-emitting elements 120 as shown in FIG. 4B, for example. In this case, the first light-confining layer 122 may be in contact with the top surface of the partition wall 104. Alternatively, the first light-confining layer 122 may be separated from the adjacent light-emitting elements 120 as shown in FIG. 4C. In this case, the EL layer 108 is in contact with the top surface of the partition wall 104. Alternatively, the EL layers 108 may be separated between the adjacent light-emitting elements 120 as shown in FIG. 5A to FIG. 5C. In this case, the second electrode 110 may be in contact with the first light-confining layer 122 as shown in FIG. 5A and FIG. 5B or in contact with the partition wall 104, the first light-confining layer 122, and the second light-confining layer 124 as shown in FIG. 5C. Furthermore, the top surface of the EL layer 108 and a top surface of the first light-confining layer 122 may exist in the same plane (FIG. 5B), or all of the top surfaces of the EL layer 108, the first light-confining layer 122, and the second light-confining layer 124 may exist in the same plane.
In the structure described above, the light emitted in the lateral direction from the emission layer 108b is reflected at an interface between the first light-confining layer 122 and the second light-confining layer 124. Additionally, a leakage of the light from the second light-confining layer 124 does not readily occur because the thickness W2 of the second light-confining layer 124 is small. Therefore, similar to the light-emitting element 100, an increase in emission efficiency due to the vertical-mode resonance is realized, and the light in the lateral direction from the light-emitting element 100 can be efficiently extracted. Accordingly, implementation of the present embodiment enables production of a light-emitting element with high color purity and emission efficiency.
Third Embodiment
In the present embodiment, a display device 130 having the light-emitting elements 100 shown in FIG. 1A and FIG. 1B and a manufacturing method thereof are explained. An explanation of the structures the same as or similar to those of the First and Second Embodiments may be omitted.
1. Outline Structure
A schematic top view of the display device 130 is shown in FIG. 6. The display device 130 possesses a substrate 132 and has a variety of patterned insulating films, semiconductor films, and conductive films thereover. Appropriate combination of these films allows the formation of a plurality of pixels 134 and driver circuits (scanning-line driver circuits 138, signal-line driver circuit 140) for driving the pixels 134. Each pixel 134 is a minimum unit providing color information and a region including a pixel circuit for driving the light-emitting element 100 as described below. The plurality of pixels 104 is periodically arranged and defines a display region 136.
The scanning-line driver circuits 138 and the signal-line driver circuit 140 are arranged in a periphery of the display region 136. Wirings 142 extend from the display region 136, the scanning-line driver circuits 138, and the signal-line driver circuit 140 to a side of the substrate 132 and are exposed at a vicinity of an edge portion of the substrate 132 to form terminals (not illustrated). The wirings 142 are electrically connected to a connector 144 such as a flexible printed circuit substrate (FPC) through the terminals. In the example shown here, a driver IC 146 having an integrated circuit formed over a semiconductor substrate is further mounted over the connector 144. Image signals and a power source are supplied from an external circuit (not illustrated) through the driver IC 146 and the connector 144 and transmitted to each pixel 134 through the scanning-line driver circuits 138 and the signal-line driver circuit 140 by the wirings 142. The pixels 104 are controlled and driven on the basis of the image signals and the power source, by which an image is displayed on the display region 136. A configuration of the driver circuits and the driver IC 146 is not limited to that shown in FIG. 6: the driver IC 146 may be mounted over the substrate 132, and the function of the signal-line driver circuit 140 may be integrated with the driver IC 146, for example.
2. Structure of Pixel 2-1. Pixel Circuit
As described above, the pixel circuit including the light-emitting element 100 is fabricated in each pixel 134 with a variety of patterned insulating films, semiconductor films, and conductive films. A structure of the pixel circuit may be arbitrarily selected, and an example is illustrated in FIG. 7 as an equivalent circuit.
The pixel circuit shown in FIG. 7 possesses a driving transistor 172, an emission-controlling transistor 180, a compensating transistor 178, an initialization transistor 174, a writing transistor 176, a storage capacitor 184, and a supplementary capacitor 186 in addition to the light-emitting element 100. A capacitor 188 is not an independent capacitor element but parasitic capacitance of the light-emitting element 100. A high potential PVDD is provided to a high-potential power-source line 150, and a potential thereof is supplied to the pixels 134 connected to each column through a current-supplying line 152. The light-emitting element 100, the driving transistor 172, the emission-controlling transistor 180, and the compensating transistor 178 are connected in series between the high-potential power-source line 150 and a low-potential power source line 154. The low-potential power source line 154 is provided with a low potential PVSS.
One terminal of the driving transistor 172 is electrically connected to the high-potential power-source line 150 through the emission-controlling transistor 180 and the compensating transistor 178, and the other terminal is electrically connected to the light-emitting element 100. A gate of the driving transistor 172 is electrically connected to a first signal line 156 through the initialization transistor 174 and is also electrically connected to a second signal line 158 through the writing transistor 176. An initialization signal Vini is provided to the first signal line 156, while an image signal Vsig is provided to the second signal line 158. The initialization signal Vini is a signal which provides an initialization potential at a constant level. Operation (on/off) of the writing transistor 176 is controlled by a scanning signal SG supplied to a write-controlling scanning line 160 connected to a gate thereof. A gate of the initialization transistor 174 is connected to an initialization-control scanning line 162 provided with an initialization-control signal IG, and operation thereof is controlled with the initialization-control signal IG. When the writing transistor 176 is on and the initialization transistor 174 is off, a potential of the image signal Vsig is provided to the gate of the driving transistor 172. On the other hand, when the writing transistor 176 is off, and the initialization transistor 174 is on, a potential of the initialization signal Vini is provided to the gate of the driving transistor 172.
A compensation-control scanning line 164 applied with a compensation-control signal CG and an emission-control scanning line 168 applied with an emission-control signal BG are respectively connected to the gates of the compensating transistor 178 and the emission-controlling transistor 180. A reset-controlling line 166 is connected to one terminal of the driving transistor 172 through the compensating transistor 178. The reset-controlling line 166 is connected to a reset transistor 182 disposed in the scanning-line driver circuits 138. The reset transistor 182 is controlled by a reset-control signal RG by which a reset potential Vrst supplied to a reset signal line 170 can be applied to one terminal of the driving transistor 172 through the compensating transistor 178.
The storage capacitor 184 is disposed between the other terminal and the gate of the driving transistor 172. One terminal of the supplementary capacitor 186 is connected to the other terminal of the driving transistor 172, and the other terminal is connected to the high-potential power-source line 150. The supplementary capacitor 186 may be provided so that the other terminal is connected to the low-potential power-source line 154. The storage capacitor 184 and the supplementary capacitor 186 are formed in order to maintain a gate-source voltage Vgs corresponding to the image signal Vsig when the image signal Vsig is provided to the gate of the driving transistor 172.
The signal-line driver circuit 140 respectively outputs the initialization signal Vini and the image signal Vsig to the first signal line 156 and the second signal line 158. The scanning-line driver circuits 138 respectively output the scanning signal SG, the initialization-control signal IG, the compensation-control signal CG, the emission-control signal BG, and the reset-control signal RG to the write-controlling scanning line 160, the initialization-control scanning line 162, the compensation-control scanning line 164, the emission-control scanning line 168, and a gate of the reset transistor 182.
2-2. Cross-Sectional Structure
A schematic cross-sectional view of the display device 130 is shown in FIG. 8. In FIG. 8, a cross-sectional structure of the driving transistors 172, the storage capacitors 184, the supplementary capacitors 186, and the light-emitting elements 100 in adjacent three pixels 134 formed over the substrate 132 is illustrated.
Each element included in the pixel circuit is disposed over the substrate 132 through an undercoat 190. The substrate 132 may contain glass, quartz, or plastics. The use of plastic provides flexibility to the substrate 132. As plastics, a polymer such as a polyimide, a polyamide, a polyester, and a polycarbonate is represented, and a polyimide having a high thermal resistivity is preferred among them.
The undercoat 190 may have a single-layer structure as shown in FIG. 8 or may be structured with a plurality of films. In the case of using a plurality of films, a film containing silicon oxide, a film containing silicon nitride, and a film containing silicon oxide may be formed in this order over the substrate 132.
The driving transistor 172 includes a semiconductor film 192, a gate insulating film 194, a gate electrode 196, and source/drain electrodes 200 and 202. The gate insulating film 194 is sandwiched by the gate electrode 196 and the semiconductor film 192. The gate electrode 196 is arranged so as to intersect at least a part of the semiconductor film 192 through the gate insulating film 194, and a channel region 192a is formed in the region where the gate electrode 196 overlaps with the semiconductor film 192. The semiconductor film 192 further possesses low-concentration impurity regions 192c sandwiching the channel region 192a and doped with an impurity as well as source/drain regions 192b sandwiching these regions and doped with an impurity. An impurity concentration in the low-concentration impurity region 192c is lower than that of the source/drain region 192b. The driving transistor 172 is a top-gate type transistor in the example shown in FIG. 8. However, there is no limitation to the structure of the transistors included in the pixel circuit, and a bottom-gate type transistor may be employed. Moreover, there is no limitation to the vertical relationship between the source/drain electrodes 200 and 202 and the semiconductor film 192.
A capacitor electrode 204 existing in the same layer as the gate electrode 196 is disposed so as to overlap with one of the source/drain regions 192b via the gate insulating film 194. An interlayer insulating film 198 is provided over the gate electrode 196 and the capacitor electrode 204. Openings reaching the semiconductor film 192 are formed in the interlayer insulating film 198 and the gate insulating film 194, and the source/drain electrodes 200 and 202 are arranged so as to cover the openings. A part of the source/drain electrode 202 overlaps with a part of the source/drain region 192b and the capacitor electrode 204 via the interlayer insulating film 198, and the storage capacitor 184 is configured by a part of the source/drain region 192b, a part of the gate insulating film 194, the capacitor electrode 204, the interlayer insulating film 198, and a part of the source/drain electrode 202.
A leveling film 206 is further provided over the driving transistor 172 and the storage capacitor 184. The leveling film 206 has an opening reaching the source/drain electrode 202, and a connection electrode 208 covering this opening and a part of a top surface of the leveling film 206 is formed so as to be in contact with the source/drain electrode 202. A supplementary capacitor electrode 210 is further disposed over the leveling film 206. The connection electrode 208 and the supplementary capacitor electrode 210 may be formed simultaneously or may be formed in different steps so as to include different materials. In the former case, the connection electrode 208 and the supplementary capacitor electrode 210 exist in the same layer and possess the same composition.
A supplementary capacitor insulating film 212 is prepared so as to cover the connection electrode 208 and the supplementary capacitor electrode 210. The supplementary capacitor insulating film 212 does not cover a part of the connection electrode 208 in the opening of the leveling film 206 and exposes a top surface of the connection electrode 208, by which electrical connection between the first electrode 102 formed thereover and the source/drain electrode 202 is realized. An opening 214 may be formed in the supplementary capacitor insulating film 212 in order to allow contact between the leveling film 206 and the partition wall 104 formed thereover. Note that the formation of the connection electrode 208 and the opening 214 is optional. The formation of the connection electrode 208 prevents corrosion of a surface of the source/drain electrode 202 in the following process, thereby preventing an increase of contact resistance of the source/drain electrode 202. Impurities in the leveling film 206 can be removed through the opening 214, by which reliability of the pixel circuit and the light-emitting element 100 can be improved.
The first electrode 102 is fabricated over the supplementary capacitor insulating film 212 so as to cover the connection electrode 208 and the supplementary capacitor electrode 210. The supplementary capacitor insulating film 212 is sandwiched by the supplementary capacitor electrode 210 and the first electrode 102, and the supplementary capacitor 186 is formed with this structure. The first electrode 102 is shared by the supplementary capacitor 186 and the light-emitting element 100.
The partition wall 104 is fabricated over the first electrode 102 to cover the edge portion of the first electrode 102. Depressions and projections caused by the first electrode 102 are reduced by the partition wall 104, which prevents disconnection of the EL layer 108 and the second electrode 110 formed thereover. The light-confining layer 106 is provided so as to cover at least a part of the side surface of the partition wall 104, and the EL layer 108 in contact with the first electrode 102 and the light-confining layer 106 is arranged over the first electrode 102. The second electrode 110 in contact with the EL layer 108 is disposed over the EL layer 108.
As an optional structure, a passivation film 216 is arranged over the second electrode 110. The structure of the passivation film 216 may be also arbitrarily determined, and a single-layer structure or a stacked-layer structure may be employed. In the case of a stacked-layer structure, a structure may be utilized where a first layer 216a including a silicon-containing inorganic compound, a second layer 216b including a resin, and a third layer 216c including a silicon-containing inorganic compound are stacked in this order. As a silicon-containing inorganic compound, silicon nitride and silicon oxide are represented. As a resin, an epoxy resin, an acrylic resin, a polyester, a polycarbonate, and the like are exemplified.
2-3. Manufacturing Method
A state is illustrated in FIG. 9A in which the driving transistor 172, the storage capacitor 184, and the supplementary capacitor 186 including the first electrode 102 are formed over the substrate 132 through the undercoat 190. A detailed explanation is omitted because these elements can be fabricated by applying known methods.
The partition wall 104 is formed so as to cover the depressions and projections caused by the edge portion of the first electrode 102 and the opening formed in the leveling film 206 (FIG. 9B). The partition wall 104 includes the material described in the First Embodiment and may be formed by applying the material or a precursor thereof with a spin-coating method, an ink-jet method, or a printing method, followed by performing light exposure, development, and baking on the obtained film.
Next, the light-confining layer 106 covering at least a part of the side surface of the partition wall 104 and in contact with the partition wall 104 and the first electrode 102 is formed. Specifically, the polymer described in the First Embodiment or a precursor thereof is applied over the partition wall 104 and the first electrode 102 by applying a spin-coating method, an ink-jet method, or a printing method (FIG. 9B). After that, light-exposure is carried out through a photomask 220 (FIG. 10A). The photomask 220 is provided with a light-shielding portion 220 blocking light to be applied, and the photomask 220 is arranged over the substrate 132 so that the light-shielding portion 222 overlaps with the region in which the light-confining layer 106 is to be prepared. After that, light exposure, development using an etchant, and baking are carried out to form the light-confining layer 106 (FIG. 10B). Note that, when an inorganic compound is used, the light-confining layer 106 may be fabricated by forming a film of an inorganic compound with an evaporation method, a sputtering method, a chemical vapor deposition (CVD) method, or the like, followed by processing the film with etching.
After that, the EL layer 108 in contact with the first electrode 102 and the light-confining layer 106 is formed over the first electrode 102 by applying an evaporation method, an ink-jet method, a spin-coating method, or the like. Next, the second electrode 110 is formed over the EL layer 108 by using an evaporation method or a sputtering method (FIG. 11A). The passivation film 216 is prepared over the second electrode 110 (FIG. 11B). A detailed explanation is omitted because the EL layer 108, the second electrode 110, and the passivation film 216 can be prepared by applying known methods.
Through the processes describe above, the display device 130 can be manufactured. As can be understood from the above explanation, the display device 130 can be manufactured by utilizing common semiconductor-manufacturing processes. Hence, implementation of the present embodiment allows production of the display device 130 without providing large stress on the process. In addition, the light-emitting element 100 is capable of showing excellent color purity and high emission efficiency. Therefore, the present embodiment enables production of a display device having high color reproducibility and low power consumption.
The aforementioned modes described as the embodiments of the present invention can be implemented by appropriately combining with each other as long as no contradiction is caused. Furthermore, any mode which is realized by persons ordinarily skilled in the art through the appropriate addition, deletion, or design change of elements or through the addition, deletion, or condition change of a process is included in the scope of the present invention as long as they possess the concept of the present invention.
In the specification, although the cases of the organic EL display device are exemplified, the embodiments can be applied to any kind of display devices of the flat panel type such as other self-emission type display devices, liquid crystal display devices, and electronic paper type display device having electrophoretic elements and the like. In addition, it is apparent that the size of the display device is not limited, and the embodiment can be applied to display devices having any size from medium to large.
It is properly understood that another effect different from that provided by the modes of the aforementioned embodiments is achieved by the present invention if the effect is obvious from the description in the specification or readily conceived by persons ordinarily skilled in the art.
1. A light-emitting element comprising:
a first electrode;
a partition wall covering an edge portion of the first electrode;
a light-confining layer in contact with a side surface of the partition wall and the first electrode;
an electroluminescence layer over the first electrode and in contact with the first electrode and the light-confining layer; and
a second electrode over the electroluminescence layer,
wherein a refractive index of the light-confining layer is lower than a refractive index of the electroluminescence layer.
2. The light-emitting element according to claim 1,
wherein a permittivity of the light-confining layer is lower than a permittivity of the electroluminescence layer.
wherein an angle between the side surface of the partition wall and a surface of the partition wall in contact with the first electrode is equal to or more than 80° and less than 90°.
wherein a width of a surface of the light-confining layer in contact with the first electrode is equal to or more than 50 nm and equal to or less than 200 nm.
wherein the light-confining layer is in contact with a top surface of the partition wall.
wherein the second electrode is in contact with the light-confining layer.
wherein the second electrode is in contact with the partition wall.
wherein the first electrode has a reflective surface reflecting visible light, and
an optical distance between the reflective surface and the second electrode is an odd multiple of one fourth of an emission wavelength of the electroluminescence layer.
9. A display device comprising:
a first light-emitting element;
a second light-emitting element adjacent to the first light-emitting element; and
a partition wall between the first light-emitting element and the second light-emitting element each comprising: a first electrode having an edge portion covered by the partition wall; a light-confining layer in contact with a side surface of the partition wall and the first electrode; an electroluminescence layer over the first electrode and in contact with the first electrode and the light-confining layer; and a second electrode over the electroluminescence layer,
wherein a refractive index of the light-confining layer is lower than a refractive index of the electroluminescence layer in each of the first light-emitting element and the second light-emitting element.
10. The display device according to claim 9,
wherein a permittivity of the light-confining layer is lower than a permittivity of the electroluminescence layer in each of the first light-emitting element and the second light-emitting element.
wherein an angle between the side surface of the partition wall and a surface of the partition wall in contact with the first electrode is equal to or more than 80° and less than 90° in each of the first light-emitting element and the second light-emitting element.
wherein a width of a surface of the light-confining layer in contact with the first electrode is equal to or more than 50 nm and equal to or less than 200 nm in each of the first light-emitting element and the second light-emitting element.
wherein the light-confining layer is in contact with a top surface of the partition wall and shared by the first light-emitting element and the second light-emitting element.
wherein the second electrode is shared by the first light-emitting element and the second light-emitting element and in contact with the light-confining layers of the first light-emitting element and the second light-emitting element.
wherein the second electrode is shared by the first light-emitting element and the second light-emitting element and in contact with the partition wall.
wherein, in each of the first light-emitting element and the second light-emitting element:
the first electrode has a reflective surface reflecting visible light; and
17. A light-emitting element comprising:
a first light-confining layer covering at least a part of a side surface of the partition wall;
a second light-confining layer between and in contact with the first light-confining layer and the partition wall;
an electroluminescence layer over the first electrode and in contact with the first electrode and the first light-confining layer; and
wherein a refractive index of the second light-confining layer is lower than a refractive index of the electroluminescence layer and a refractive index of the first light-confining layer.
18. A display device comprising:
a partition wall between the first light-emitting element and the second light-emitting element each comprising: a first electrode having an edge portion covered by the partition wall; a first light-confining layer covering at least a part of a side surface of the partition wall; a second light-confining layer between and in contact with the first light-confining layer and the partition wall; an electroluminescence layer over the first electrode and in contact with the first electrode and the first light-confining layer; and a second electrode over the electroluminescence layer,
6605826 August 12, 2003 Yamazaki
8344374 January 1, 2013 Yamazaki
8581265 November 12, 2013 Hatano
20170123268 May 4, 2017 Sasaki et al.
2017-062902 March 2017 JP
2017-107181 June 2017 JP
Filed: Nov 5, 2018
Date of Patent: Feb 4, 2020
Assignee: Japan Display Inc. (Tokyo)
Inventor: Nobuto Managaki (Tokyo)
Primary Examiner: Chandra Chaudhari
Current U.S. Class: In Array Having Structure For Use As Imager Or Display, Or With Transparent Electrode (257/72)
International Classification: H01L 27/32 (20060101); H01L 27/12 (20060101); H01L 51/52 (20060101); H01L 33/40 (20100101); H01L 27/15 (20060101);


text:
Matthew McConaughey to play Harvey Dent in Matt Reeves' The Batman? Deets inside
Matt Reeves' standalone Batman movie is in the news lately for its star cast. While Robert Pattinson has been roped to play the cape crusader of the Gotham city, Zoe Kravitz will be essaying his love interest, Catwoman, in...
Shah Rukh Khan and Salman Khan to reunite in Aamir Khan's Laal Singh Chaddha? details inside
Aamir Khan's Laal Singh Chaddha is in the news ever since the actor announced the project. The movie will be a Hindi adaptation of the iconic Hollywood flick Forrest Gump starring Tom Hank and reports suggest that the movie is going...
Tara Sutaria and Sidharth Malhotra talk about their rumoured relationship, read what they said
Tara Sutaria is said to be the next big thing in the Bollywood industry and has earned a great fan following with his film debut under the Karan Johar's banner production, Student of the Year 2, alongside Tiger Shroff and...
Salman Khan and Disha Patani commence shooting for Radhe: Your Most Wanted Bhai, check picture
Salman Khan never fails to give Eidi to his fans and following the trend of every year, Salman Khan recently announced actioner Radhe: Your Most Wanted Bhai during the shooting of Dabangg 3. While the actor was busy shooting for the...
Vicky Kaushal to romance Sara Ali Khan in Aneez Bazmi's next madcap entertainer
Sara Ali Khan has been hitting the right chords ever since she made her debut in the Bollywood industry with the romantic-drama Kedarnath opposite Sushant Singh Rajput. While the actress is busy shooting for Imtiaz Ali's Aaj Kal and David Dhawan's Coolie...
Box Office Report: Records shattered by Housefull 4, enters 100 crore club in 5 days
The fourth instalment of the epic comedy-drama franchise Housefull has made a huge buzz among its fans. With an ensemble cast of Akshay Kumar, Kriti Sanon, Riteish Deshmukh, Kriti Kharbanda, Bobby Deol, and Pooja Hedge, Housefull 4 had a great start...
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redpajama_set_name: RedPajamaCommonCrawl


text:
Q: AppEngine, entity missing? So I have 2 model classes:
class Profile(db.Model):
  """Profiles are merely lighter versions of Users. The are only used for the
  purpose of notification
  """
  created_at = db.DateTimeProperty(auto_now_add=True)
  created_by = None   # TODO User class
  name = db.StringProperty()
  email = db.EmailProperty()
  phone = db.PhoneNumberProperty()

class Notification(db.Model):
  LEVELS = {
      'INFO': 'INFO',
      'WARNING': 'WARNING',
      'CRITICAL': 'CRITICAL'
  }
  created_by = None   # TODO user class
  created_at = db.DateTimeProperty(auto_now_add=True)
  profile = db.ReferenceProperty(Profile, collection_name='notifications')
  level = db.StringProperty()

This is what my JSONencoder looks like:
class JsonEncoder(json.JSONEncoder):
  def default(self, obj):
    if isinstance(obj, datetime.datetime):
      return obj.isoformat()
    elif isinstance(obj, Profile):
      return dict(key=obj.key().id_or_name(),
                  name=obj.name, email=obj.email, phone=obj.phone)
    elif isinstance(obj, Limits):
      return None
    else:
      return json.JSONEncoder.default(self, obj)

Basically, one can assign a notification to a profile such that when a notification fires, all the profiles associated with that notification will be notified.
In my html, I have a form allowing users to create a notifiation:
  <form action="{{ url_for('new_notification') }}" method=post>

    Name:
    <input name='name' type='text' value='Select from above' disabled=true />

    <input name='key' type='hidden' value='Select from above' />

    Type:
    <select name='level'>
      {% for k,v in notification_cls.LEVELS.iteritems() %}
      <option value="{{ v }} ">{{ k }}</option>
      {% endfor %}
    </select>

    <input type="submit" value="Submit">
  </form>

However, I am seeing some strange things happening in my method to create a notification:
@app.route('/notifications/new/', methods=['GET', 'POST'])
def new_notification():
  """Displays the current notifications avaiable for each profiles
  """
  if request.method == 'GET':
    return render_template('new_notification.html',
                           notification_cls=Notification)
  else:
    profile_key_str = request.form.get('key', None)
    level = request.form.get('level', None)
    if not profile_key_str or not level:
      abort(404)

    profile_key = db.Key.from_path('Profile', profile_key_str)

    profile = Profile.get(profile_key)
    print profile     # This results in None??

    notification = Notification(parent=profile)   # Ancestor for strong consistency
    notification.profile = profile_key
    notification.level = level
    notification.put()
    return redirect(url_for('list_notifications'), code=302)

So a user can create a profile on the new_notifications page. After that, my server will send the newly created entity's key via ajax to the same page containing the form. This will set the hidden input's value.
Somehow, in my new_notification method, Profile does not exist!!!! I am sort of suspicious of AppEngine's "eventual consistency" policy but I've been waiting for 30 mins and the results is still None.
Any ideas what I am doing wrong?
EDIT:
I forgot to include the method which calls the JSONEncoder for my JS
@app.route('/profiles/', methods=['GET'])
def ajax_list_profiles():
  def _dynatable_wrapper(profiles):
    return {'records': profiles,
            'queryRecordCount': len(profiles),
            'totalRecordCount': len(profiles)}
  name = request.args.get('queries[search]', None)
  if not name:
    profiles = db.Query(Profile).order('name').fetch(None)
    return json.dumps(_dynatable_wrapper(profiles), cls=JsonEncoder)
  else:
    profiles = db.Query(Profile).filter("name =", name).order('name').fetch(None)
    return json.dumps(_dynatable_wrapper(profiles), cls=JsonEncoder)

A: You probably want to use an int for the key path, otherwise it'll think its a keyname.

redpajama_set_name: RedPajamaStackExchange


If you are seeking an effective way to deal with wrinkles, improve sagging skin and lessen deep lines, you might want to consider dermal filler injections. This treatment can refresh and reinvigorate the skin, adding volume and filling those annoying wrinkles and lines. Dermal fillers can also be used to enhance the cheeks, jawline, chin, lips, marionette lines (long, vertical lines that extend from the outer corners of the mouth down to the jawline) and nasolabial folds (lines that extend from the corners of the nose down to the corners of the mouth).
Dermal fillers are synthetic or natural gels that are injected into the skin in order to reduce the appearance of lines and add volume. Most of the dermal fillers used today are temporary and biodegradable, but there are a few permanent fillers available too.
Dermal fillers are injected into the skin, but don't worry – it's not as painful as it's sounds! The procedure does come with a little discomfort and certain areas (such as the lips) are likely to be more sensitive than others. Dermal fillers often contain local anaesthetic, which automatically imparts pain relief whilst you are injected. Alternatively, anaesthetic cream or ice may be applied to skin in order to numb the area.
Which Areas Can Benefit from Dermal Filler Injections?
Who Can Have Derma Fillers?
Are taking medication that impacts upon your immune system.
Have experienced a reaction to dermal fillers / local anaesthetic in the past.
Have suffered from a skin infection or are feeling unwell.
Have experienced problems related to bleeding.
Are taking medication, such as aspirin, which affects bleeding.
You are taking or have taken Roaccutane (acne treatment) during the last 18 months.
You will receive guidance on aftercare, but you should be able to get back to your normal activities fairly quickly, (however it's not a good idea to undertake any vigorous exercise for 48 hours). You might experience some degree of redness, pin prick marks, or tenderness - however this should settle down within a couple of days.
You might also notice bruising or swelling (which will be more apparent the day after the procedure) – this may take a couple of weeks to fully disappear. We suggest cold packs to alleviate any swelling and arnica cream to reduce bruising.
How Quickly Will I See the Results and How Long Will They Last?
Expect to see a change almost immediately. However, keep in mind that swelling may cause the product to feel clumpy and rigid at first. It's best to judge the final results after two weeks (when you will be invited to attend to review), so we can assess the outcome together.
Results can last between four months and a whole year (based upon the product used and which area has been treated). In the unlikely case that you experience any problems you will be able to see your practitioner for advice and to discuss further treatment.


It may not pack the same punch as much of the competition but the low price tag makes for a compelling argument in its favour.
One attribute shared by all the blade servers we've reviewed is a high price tag. Not any more. The SilverEdge 6000TUD from Evesham.com has shifted the goalposts, with this compact 3U chassis offering an enterprise level feature set at a remarkably low price. The 6000TUD is actually a TUD-3114 from California-based Tatung, which entered the blade server market at the end of 2003 with the introduction of two low-cost systems. At 3U high, blade server chassis' don't get any lower than this and, despite the fact that only single Xeon blades are supported, it still manages to pack 196 processors into an industry-standard rack. At less than half the price of much of the competition you'd expect build quality to be a bit ropey but nothing could be further from the truth. The 6000TUD is as well engineered as the RLX Technologies System 600ex. Fault tolerance is also impressive as the review system came equipped with a single 1200W power supply mounted in a tray at the rear, to which you can add a redundant PSU, both hot-swappable. Two hot-swap blower fans deal efficiently with general cooling and, despite their size, are fairly quiet. The system came supplied with both a primary management blade and a switch blade but there's room on the opposite side for a pair of secondary redundant units as well, so the chassis has no single point of failure. The management blade provides serial and 1000BaseT network ports for local and remote management while the switch blade consolidates the Gigabit server blade ports down to three external 1000BaseT connections. Three more internal network connections link to both management modules, and the secondary switch blade, so you can easily separate management and network traffic. The price for the review unit includes three server blades, and extra modules with the same configuration cost £1,099 each. Two drawbacks mar this rosy picture. First, the server blades in this compact chassis are too small to support dual Xeon processors and second, storage options are more limited than much of the competition. The single 2GHz Xeon processor sits at the front underneath a mighty passive heatsink and a pair of DIMM sockets reside further back. Each is occupied by 512MB of PC2100 ECC memory but the Intel E7501 chipset supports a maximum of 4GB so there's plenty of room to expand. Storage is handled by a single 30GB 2.5in. low-profile hard disk mounted at the rear but you've run out of space now, as there's no room for a second drive. The two internal Gigabit ports are linked separately to each switch blade, while a small KVM port at the front of each module provides local access via the supplied cable, which can also be hot-swapped. Blade servers need facilities for OS deployment, management and monitoring and we found the bundled ManageSite software provides plenty of these essential tools. Once you've assigned an IP address to the primary management module, and external network ports, via a CLI session, you can access the system remotely. You can easily create and deploy OS images to selected servers either manually, or at allotted times, using the task scheduler. The main interface is well designed and allows servers to be placed into logical groups based on location, installed software or ownership. Hardware details on all components are extensive but although the switch blades support VLANs and port trunking these can only be configured from the CLI, as they don't offer an HTTP server for browser access. Even so, you can keep a close eye on system operations or performance, while warnings can be linked to thresholds allowing critical faults to generate email or pager messages to selected users. The SilverEdge 6000TUD may not pack the same punch as much of the competition but the low price tag makes for a compelling argument in its favour. Build quality, management and expansion potential are still comparatively good making this a fine choice for smaller businesses looking to consolidate operations, ditch their pedestal servers and save on floor space.
At this low price you'd expect sacrifices but overall the 6000TUD delivers an impressive, low-profile package. Storage options are basic but, despite the lack of support for dual Xeons, processing density is actually better than IBM's BladeCentre and HP's ProLiant BL20 p-Class, making this well worth considering for general-purpose data centre duties.


text:
Weekend Life
Tenders & Jobs
Weekend Post
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Councilors' benefits debacle-savingram reveals detail
Households spending to drive economic recovery
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Thiite, Lesaso, Letsholo tipped for Ministerial posts
Mining production rebounds to pre-Covid-19 levels
Exports plummeted in October 2021
Debswana receives African award from Absa for its CEE policy
ODC 2021 sales revenue set to surpass P10bn
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BFA faces ministry backlash
Mamelodi rejects BFA CEO post
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By Alfred Masokola
Minister of Tertiary Education, Research, Science and Technology, Dr Alfred Madigele has recently told the Tertiary Education Financing Pitso recently that the current tertiary education funding model used by government is not sustainable.
Madigele told the Pitso organised by the Human Resource Development Council (HRDC) that Botswana, like many other countries face the challenge of tertiary education financing occasioned in part by what he called "massification": a massive increase in tertiary education enrolment; ever increasing costs; equally important competing priorities and dwindling financial resources.
The minister however highlighted government's obligation as envisaged by the Vision 2016 Pillar of an "Informed and Educated" and Pillar 2 of the recently launched Vision 2036: "Human and Social Development" which highlights that education and skills are the basis for human resource development.
"Government has traditionally been the sole sponsor of tertiary education students. We have provided loans and grants to students to cover both tuition and students' upkeep. In addition, the Government provides 100% funding to the public tertiary institutions to meet both their recurrent and development expenditure," he said.
"The sponsorship evolved overtime from a bursary to a grant/loan scheme where beneficiaries were expected to contribute towards the cost of their training through recovery."
Madigele explained that in 1995, under the bursary scheme, sponsorship was availed to everyone and graduates were expected to pay 5% of their initial salary at the time they started, tied to the duration of the programme. Whereas under the grant/loan scheme, sponsorship was availed to all those who completed senior secondary school and could find admission to local public tertiary institutions.
"Need I point out at this juncture that our recovery efforts have not been the best and I think I will be correct to say we could be having amongst our mist here, individuals who still have not paid back. In addition, Government provides 100% funding to the public tertiary institutions to meet both their recurrent and development expenditure," he noted.
He said although those who could find admissions in private institutions had to sponsor themselves in the past, in 2007 government took a deliberate decision to sponsor students to private tertiary education institutions.
"As a result of this initiative, the total number of students both at public and private institutions who were sponsored by Government increased substantially," he stated.
"While all this is desirable, it is not sustainable in view of other competing demands on Government and in light of the declining government revenues over the past five years."
He remarked that financing tertiary education and the challenges it poses for governments have lately become a topical issue around the world.
"The search for better strategies for financing tertiary education has thus become a subject of wide discussions at forums involving international organizations among others, UNESCO, IMF, OECD and The World Bank," he highlighted.
Madigele noted that the issue of tertiary education financing in the case of Botswana becomes a challenge in view of the ever-growing numbers of secondary school graduates who seek to access tertiary education.
The Tertiary Education Policy (2008) set the tertiary participation target for the 18 – 24 year olds for 2025 at 25% from the 11.4% rate in 2007/8. Madigie, who is also Member of Parliament for Molapowabojang/Mmathete said considering the projected senior secondary school output at 30 points minimum entry grade for tertiary, it is possible that enough numbers could be raised to meet the 25% target.
"Given the challenges I mentioned earlier, the question that immediately follows,, however distinguished guests, ladies and gentlemen,, is: "whether Can the Government as the current sole sponsor of tertiary education can sustainably afford to pay for the continually increasing numbers"? he asked rhetorically.
Madigele expressed concern that the HRDC reports the total number of BGCSE and equivalent examinations graduates is projected to increase overtime.
"The challenge we face now is to diversify our tertiary education is to ensure optimality and sustainability of tertiary funding sources while pursuing the goals of increased access, equity and improved quality in the country's tertiary education system," he said.
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Mowana Copper Mine in Dukwi will finally pay its former employees a total amount of P23, 789, 984.00 end of this month. For over three years Mowana Copper Mine has been under judicial management. Updating members, Botswana Mine Workers Union (BMWU) Executive Secretary Kitso Phiri this week said the High Court issued an order for the implementation of the compromise scheme of December 9, 2021 and this was to be done within 30 days after court order.
"Therefore payment of benefits under the scheme including those owed to Messina Copper Botswana employees should be effected sometime in January latest end of January 2022," Kitso said. Kitso also explained that cash settlement will be 30 percent of the total Messina Copper Botswana estate and negotiated estate is $3,233,000 (about P35, 563,000).
Messina Copper was placed under liquidation and was thereafter acquired by Leboam Holdings to operate Mowana Mine. Leboam Holdings struck a deal with the Messina Copper's liquidator who became a shareholder of Leboam Holdings. Leboam Holdings could not service its debts and its creditors placed it under provisional judicial management on December 18, 2018 and in judicial management on February 28, 2019.
A new company Max Power expressed interest to acquire the mining operations. It offered to take over the Mowana Mine from Leboam Holdings, however, the company had to pay the debts of Leboam including monies owed to Messina Copper, being employees benefits and other debts owed to other creditors.
The monies, were agreed to be paid through a scheme of compromise proposed by Max Power, being a negotiated payment schedule, which was subject to the financial ability of the new owners. "On December 9, 2021, Messina Copper liquidator, called a meeting of creditors, which the BMWU on behalf of its members (former Messina Copper employees) attended, to seek mandate from creditors to proceed with a proposed settlement for Messina Copper on the scheme of compromise. It is important to note that employee benefits are regarded as preferential credit, meaning once a scheme is approved they are paid first."
Negotiated estate is P35, 563,000
Aubrey Lute
A savingram the Ministry of Local Government and Rural Development sent to Town Clerks and Council Secretaries explaining why councilors across the country should not have access to their terminal benefits before end of their term has been revealed.
The contents of the savingram came out in the wake of a war of words between counselors and the Ministry of Local Government and Rural Development. The councilors through the Botswana Association of Local Authorities (BALA) accuse the Ministry of refusing to allow them to have access to their terminal benefits before end of their term.
This has since been denied by the Ministry. In the savingram to town councils and council secretaries across the country, Permanent Secretary in the Ministry of Local Government and Rural Development Molefi Keaja states that, "Kindly be advised that the terminal benefits budget is made during the final year of term of office for Honorable Councilors." Keaja reminded town clerks and council secretaries that, "The nominal budget Councils make each and every financial year is to cater for events where a Councilor's term of office ends before the statutory time due to death, resignation or any other reason."
The savingram also goes into detail about why the government had in the past allowed councilors to have access to their terminal benefits before the end of their term. "Regarding the special dispensation made in the 2014-2019, it should be noted that the advance was granted because at that time there was an approved budget for terminal benefits during the financial year," explained Keaja. He added that, "Town Clerks/Council Secretaries made discretions depending on the liquidity position of Councils which attracted a lot of audit queries."
Keaja also revealed that councils across the country were struggling financially and therefore if they were to grant councilors access to their terminal benefits, this could leave their in a dire financial situation. Given the fact that Local Authorities currently have cash flow problems and budgetary constraints, it is not advisable to grant terminal benefits advance as it would only serve to compound the liquidity problems of councils.
It is understood that the Ministry was inundated with calls from some Councils as they sought clarification regarding access to their terminal benefits. The Ministry fears that should councils pay out the terminal benefits this would affect their coffers as the government spends a lot on councilors salaries.
Reports show that apart from elected councilors, the government spends at least P6, 577, 746, 00 on nominated councilors across the country as their monthly salaries. Former Assistant Minister of Local Government and Rural Development, Botlogile Tshireletso once told Parliament that in total there are 113 nominated councilors and their salaries per a year add up to P78, 933,16.00. She added that their projected gratuity is P9, 866,646.00.
A surge in consumer spending is expected to be a key driver of Botswana's economic recovery, according to recent projections by Fitch Solutions. Fitch Solutions said it forecasts household spending in Botswana to grow by a real rate of 5.9% in 2022.
The bullish Fitch Solutions noted that "This is a considerable deceleration from 9.4% growth estimated in 2021, it comes mainly from the base effects of the contraction of 2.5% recorded in 2020," adding that, "We project total household spending (in real terms) to reach BWP59.9bn (USD8.8bn) in 2022, increasing from BWP56.5bn (USD8.3bn) in 2021." According to Fitch Solutions, this is higher than the pre-Covid-19 total household spending (in real terms) of P53.0 billion (USD7.8bn) in 2019 and it indicates a full recovery in consumer spending.
"We forecast real household spending to grow by 5.9% in 2022, decelerating from the estimated growth of 9.4% in 2021. We note that the Covid-19 pandemic and the related restrictions on economic activity resulted in real household spending contracting by 2.5% in 2020, creating a lower base for spending to grow from in 2021 and 2022," Fitch Solutions says.
Total household spending (in real terms), the agency says, will increase in 2022 when compared to 2021. In 2021 and 2022, total household spending (in real terms) will be above the pre-Covid-19 levels in 2019, indicating a full recovery in consumer spending, says Fitch Solutions. It says as of December 6 2021 (latest data available), 38.4% of people in Botswana have received at least one vaccine dose, while this is relatively low it is higher than Africa average of 11.3%.
"The emergence of new Covid-19 variants such as Omicron, which was first detected in the country in November 2021, poses a downside risk to our outlook for consumer spending, particularly as a large proportion of the country's population is unvaccinated and this could result in stricter measures being implemented once again," says Fitch Solutions.
Growth will ease in 2022, Fitch Solution says. "Our forecast for an improvement in consumer spending in Botswana in 2022 is in line with our Country Risk team's forecast that the economy will grow by a real rate of 5.3% over 2022, from an estimated 12.5% growth in 2021 as the low base effects from 2020 dissipate," it says.
Fitch Solutions notes that "Our Country Risk team expects private consumption to be the main driver of Botswana's economic growth in 2022, as disposable incomes and the labour market continue to recover from the impacts of the Covid-19 pandemic."
It says Botswana's tourism sector has been negatively impacted by the Covid-19 pandemic and the related travel restrictions.
According to Fitch Solutions, "The emergence of the Omicron variant, which was first detected in November 2021, has resulted in travel bans being implemented on Southern African countries such as South Africa, Botswana, Lesotho, Namibia, Zimbabwe and Eswatini. This will further delay the recovery of Botswana's tourism sector in 2021 and early 2022." Fitch Solutions, therefore, forecasts Botswana's tourist arrivals to grow by 81.2% in 2022, from an estimated contraction of 40.3% in 2021.
It notes that the 72.4% contraction in 2020 has created a low base for tourist arrivals to grow from. "The rollout of vaccines in South Africa and its key source markets will aid the recovery of the tourism sector over the coming months and this bodes well for the employment and incomes of people employed in the hospitality industry, particularly restaurants and hotels as well as recreation and culture businesses," the report says.
Fitch Solutions further notes that with economies reopening, consumers are demanding products that they had little access to over the previous year. However, manufacturers are facing several problems. It says supply chain issues and bottlenecks are resulting in consumer goods shortages, feeding through into supply-side inflation. Fitch Solutions believes the global semiconductor shortage will continue into 2022, putting the pressure on the supply of several consumer goods.
It says the spread of the Delta variant is upending factory production in Asia, disrupting shipping and posing more shocks to the world economy. Similarly, manufacturers are facing shortages of key components and higher raw materials costs, the report says adding that while this is somewhat restricted to consumer goods, there is a high risk that this feeds through into more consumer services over the 2022 year.
"Our global view for a notable recovery in consumer spending relies on the ability of authorities to vaccinate a large enough proportion of their populations and thereby experience a notable drop in Covid-19 infections and a decline in hospitalisation rates," says Fitch Solutions.
Both these factors, it says, will lead to governments gradually lifting restrictions, which will boost consumer confidence and retail sales.
"As of December 6 2021, 38.4% of people in Botswana have received at least one vaccine dose. While this is low, it is higher than the Africa average of 11.3%. The vaccines being administered in Botswana include Pfizer-BioNTech, Sinovac and Johnson & Johnson. We believe that a successful vaccine rollout will aid the country's consumer spending recovery," says Fitch Solutions. Therefore, the agency says, "Our forecasts account for risks that are highly likely to play out in 2022, including the easing of government support. However, if other risks start to play out, this may lead to forecast revisions."
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text:
Trump calls Romney a 'choker,' says Jeb is 'total fool'
By Laura Italiano
Getty Images; Getty Images; Reuters
Donald Trump hasn't announced a run for president quite yet, but that isn't stopping him from hurling stink bombs at fellow Republicans — calling Mitt Romney "a choker," Marco Rubio "a horror show" and Jeb Bush "a nice person," who's still "a total fool."
Not that he can't stand any of them.
"I like these people," Trump insisted of the GOP presidential lineup during a speech in Sarasota, Fla., Thursday night, as he accepted an award from a local Republican group.
"But they don't have it."
Trump, however, does have it — at least by his own reckoning as he thundered to 1,500 cheering fans.
Throughout his 70-minute speech, Trump boasted of his business competence, bragging, "I do it better than anybody," according to the Sarasota Herald-Tribune and other reports.
But much of Trump's time was devoted to taking hilarious pot shots at his GOP rivals-in-waiting.
Even Romney, the 2012 GOP presidential nominee who isn't running in 2016, got hit hard.
"Romney had one thing going for him," Trump sniped.
"He's good looking. Other than that, there's nothing, Okay? Even when he walked around the stage, he walked like a penguin."
In losing the 2012 election to President Obama — "a failed president" — Romney "choked," Trump huffed.
"Once a choker, always a choker."
Jeb Bush "made a total fool of himself" in waffling during recent interviews on whether his brother, George W., had been right to invade Iraq.
"How would you like him negotiating with the terrorists?" Trump chided the former Florida governor.
Rubio, the Florida senator, took heat for flubbing the same question just last weekend, despite having "the benefit of watching Jeb make a total fool out of himself" only a few days prior.
"I don't even know how he could be running for office," Trump said.
"We spend $2 trillion, we lost thousands of lives, we've got wounded warriors — who I love more than anybody — all over the place. And you can't say if it was a bad thing?"
The only woman in the GOP race, former Hewlett-Packard CEO Carly Fiorina, was run out of her company on a rail, Trump said.
Fiorina "ran a company and she got viciously fired," Trump said. "She was walked out of there and the stock went up seven points that day she got fired. That's not a good sign," he said.
"I fire people all day long. I make millions of dollars firing people on television. I know more about firing than anybody in the world . . . she got fired more viciously than anybody I've ever fired."
Filed under 2016 presidential election , barack obama , donald trump , jeb bush , john kerry , marco rubio , mitt romney
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