The basic study on improved performance of transflective liquid crystal displays

重量轻、功耗低的高质量彩色液晶显示器是高功能信息终端的重要器件。透射式LCD是移动应用的普遍首选，因为背光和环境光的反射相结合在任何环境照明强度下都能产生高能见度。无需对电池充电即可实现低功耗是延长移动设备使用期限的关键要求。为了验证采用两层延迟膜的透射式均质单元降低功耗的可能性，数值分析了器件参数，包括延迟膜的双折射色散、Δn_R(λ)和LCD的电光特性之间的关系。结果表明，即使在开启电压降低到2.0V的情况下，优化后的液晶也能产生宽视角的高质量消色差图像。因此，面板中的功耗可以降低到导通状态下工作在4.0V的电流透射型TFT-LCD的大约四分之一。此外，我们还利用前面的计算研究了提高LCD性能的可行性。通过将关断电压从0V提高到0.5V，在不影响显示特性的情况下，进一步降低了LCD的功耗。通过引入双域结构，我们还实现了视角光学性质的显著改善。此外，我们发现，利用目前的技术，我们可以很容易地生产LCD。我们通过计算证实，即使电池间隙从设计值改变到±2%，LCD的电光性能也不会受到影响。

High-quality color liquid-crystal displays (LCDs) that are light weight and low in power consumption are important devices in highly functional information terminals. Transflective LCDs are the general preference for mobile applications because the combination of backlighting and reflection of ambient light creates high visibility under any intensity of ambient illumination. Low power consumption without recharging the battery is a key requirement for extended use of mobile devices. Therefore, it is advantageous to reduce the TFT-LCD's power consumption in the panel while maintaining its superior image quality.To confirm the possibility of reducing power consumption of a transflective homogeneous-cell with two retardation films, we numerically analyzed the relationship between device parameters, including the birefringence dispersion of the retardation film, Δn_R(λ), and the electro-optical properties of the LCD.We found that the optimized LCD produces an achromatic high-quality image with wide viewing angles, even when the on-voltage is reduced to 2.0V. The power consumption in the panel can thus be decreased to about one-fourth that of a current transflective TFT-LCD operating at 4.0V in the on-state. In addition, we studied the feasibility of enhancing the performance of the LCD using previous calculations. We further reduced the power consumption of the LCD by raising the off-state voltage from 0V to 0.5V, which did not affect the display characteristics. We also realized considerable improvement in the optical properties of the viewing angle by incorporating a two-domain structure. In addition, we found that we could easily produce the LCD using present technology. We confirmed by calculation that the electro-optical properties of the LCD were not affected, even if the cell-gap changed to ±2% from the designed value.