1. Technical Field
The present invention relates to an electro-optical device, in which a gap between a pair of substrates facing each other is defined by support bodies made of an adhesive ejected from a liquid droplet ejection device main body, to a method of manufacturing an electro-optical device, and to an electronic apparatus using such an electro-optical device.
2. Related Art
A projection-type display device, such as a liquid crystal projector, or the like, has a configuration in which light irradiated from a light source is optically modulated by an electro-optical device serving as a light valve, and modulated light is projected to the front in a magnified scale. As a liquid crystal device that is an example of the electro-optical device, an active-matrix-type liquid crystal display is widely used in order to provide increased display quality.
In the active-matrix-type liquid crystal device, pixels having pixel electrodes are formed in a matrix shape on an active matrix substrate. Further, for each pixel, an active element, such as a thin film transistor (TFT) or the like, is formed.
In such an active-matrix-type liquid crystal device, a high contrast ratio is easily obtained, but a TFT, a capacitive element, and the like need to be provided for each pixel, which results in a problem in that a sufficient aperture ratio is difficult to obtain. Further, when intense light is irradiated onto a channel region or a drain terminal of the TFT, photocurrent is generated, which causes a change in characteristics of the TFT.
Therefore, a configuration has been adopted in which, among the pair of substrates constituting the liquid crystal device, a light-shielding film (black matrix) is formed on a counter substrate, on which light is incident, in order to enhance the contrast and prevent intense light from being irradiated onto the TFT.
Further, a technique has been adopted in which a layer having a plurality of minute microlenses (microlens layer) is formed on the counter substrate and incident light, which is reflected or shielded by the light-shielding layer to be lost, is condensed to openings of the pixels with the respective microlenses, thereby increasing the amount of transmitted light.
A method of manufacturing such a counter substrate with microlenses is disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2003-14907.
In the technique disclosed in Japanese Unexamined Patent Application Publication No. 2003-14907, first, a masking member is formed on a large lens glass substrate serving as a base and a resist pattern is formed on the masking member. Next, through etching with the resist pattern as a mask, openings corresponding to the plurality of microlenses are formed in the masking member. Subsequently, the resist pattern is removed.
Next, wet etching or isotropic dry etching is performed on the large lens glass substrate from the masking member to form a plurality of concave portions for the microlenses on the lens glass substrate. Then, the masking member is removed.
Subsequently, an adhesive made of a transparent resin having high refractive index is coated on the surface where the plurality of concave portions for the microlenses are formed. Then, a cover glass substrate is integrally bonded onto the adhesive.
Subsequently, on the surface of the cover glass substrate, color filters and the light-shielding film (BM: black matrix) among the pixels are formed. In addition, a common electrode made of a transparent conductive material, such as ITO (Indium Tin Oxide), is formed and an alignment film is formed on the common electrode. Accordingly, a large substrate having a plurality of chip-like counter substrates is formed.
In order to increase the amount of transmitted light from the opening of each pixel with the microlenses, in the molding of the microlens layer, it is necessary to precisely set the thickness of the microlens layer. In the molding of the microlens layer, in order to precisely set the thickness thereof, after the plurality of concave portions for the microlenses are formed on the surface of the lens glass substrate, dots of adhesive in which a gap material is mixed are drawn around the periphery of the counter substrate at predetermined internals with a dispenser or the like. Then, after the adhesive is drawn on the lens glass substrate, the cover glass substrate is bonded thereto. At this time, the gap between the cover glass substrate and the lens glass substrate is defined by the gap material and the thickness of the microlens layer is maintained to be constant. This technique has been known in the related art.
As described above, the plurality of counter substrates are formed on the large substrate. In order to increase the number of the counter substrates that can be cut out of one large substrate, the interval between the counter substrates to be formed on the large substrate needs to be small.
However, if the interval between the counter substrates is reduced, it is difficult to draw the gap material on the boundary lines between the counter substrates with the dispenser or the like. The gap material may be drawn only on the circumference of the lens glass substrate. As a result, as regards the gap between the lens glass substrate and the cover glass substrate, the deflection amount may be gradually increased from the outer circumference to the central portion and thus a deviation in thickness of the microlens layer corresponding to that amount may easily occur. Then, uniformity of the products is difficult to maintain.
The deviation in thickness of the microlens layer in one large substrate falls normally within an acceptable error range and thus the deviation does not cause product defects. However, in recent years, with demands for higher image quality, the thickness of the microlens layer must be set with higher precision. Accordingly, such demands result in defective products.