An organic light-emitting diode device, also called an OLED device, commonly includes a substrate, an anode, a hole-transporting layer made of an organic compound, an organic luminescent layer with suitable dopants, an organic electron-transporting layer, and a cathode. OLED devices are attractive because of their low driving voltage, high luminance, wide-angle viewing and capability for full-color flat emission displays. Tang et al. have described a multilayer OLED device in their U.S. Pat. Nos. 4,769,292 and 4,885,211.
Since then, a large number of different materials and designs have been described for OLED devices. For example, an OLED device comprising a matrix of pixels can be electrically driven using either a simple passive matrix or an active matrix driving scheme. In a passive matrix, the organic EL layers are sandwiched between two sets of orthogonal electrodes arranged in rows and columns, as disclosed in commonly assigned U.S. Pat. No. 5,276,380, while in an active matrix configuration, each pixel is driven by multiple circuit elements, such as provided in U.S. Pat. Nos. 5,550,066 (commonly assigned), 6,281,634, and 6,456,013. The OLED device can comprise pixels whose components emit different color light, e.g. red, green, and blue, so as to provide a full-color device. Another scheme has been to use a white-light-emitting layer, such as described by Shi in U.S. Pat. No. 5,683,823, and to use color filters in the matrix to provide red, green, and blue pixels. A variety of such color filters exist. An OLED device can be top-emitting or bottom-emitting. Microcavity structures have been used to enhance emission at a specific wavelength. Examples of microcavity structures are shown in U.S. Pat. Nos. 6,406,801, 5,780,174, and JP 11-288786. A wide variety of emitting materials of varying properties, both singlet and triplet emitters, has been used in OLED devices. Light-emitting layers generally comprise a light-emitting dopant and a host material. The choice of host material can have an effect on the performance of the emitting layer. The presence or absence of other layers, such as hole-transporting layers, electron-transporting layers, and electron-injecting layers, can have an effect on the performance of the final OLED device, as can the choice of materials used for these layers and for the electrodes. Other factors can also play a part, such as the presence or absence of polarizing layers.
This plethora of factors in OLED device construction means that it is possible to conceive of thousands of possible device constructions for a given application. This large choice in theory provides the ability to optimize displays for many different uses, as defined by the customer, because a variety of parameters can be varied and tested in OLED device construction. However, the design, construction, and testing of such a large number of devices would require considerable time and resources, making this method impractical in reality.
There exists a need for a more efficient design selection method for OLED devices, so that the chosen OLED device design can effectively meet the customer requirements.