The brightness of TFT LCD is the product of the brightness of the back light and the transmittance of the display, measured in cd/m2.It is a common practice to increase the brightness of TFT LCD screens by increasing the brightness of backlight.The side effect of this LCD design strategy for high brightness is increased cost and many other quality and reliability issues due to the rising temperature of the backlight.Therefore, the design countermeasure to improve the brightness of LCD is to improve the transmittance of TFT LCD.
To improve the transmittance of TFT LCD, we can improve the transmittance of TFT LCD from the aspects of pixel opening rate, LCD transmittance, polarizer transmittance and CF transmittance.Transmittance design of TFT LCD is a comprehensive result of pixel design and material design, which involves a wide range of aspects and many parameters.One of the main tasks of LCD high brightness design is to effectively balance the relationship between the various parameters that affect the transmittance and finally determine the transmittance value.
The factors restricting the improvement of transmittance can be roughly summarized as quality and cost.The PPI value of high-quality products is generally large (the resolution is relatively high under the same display size), but the pixel opening rate is low, and the transmittance is correspondingly low.In order to improve the color reproduction ability of TFT LCD, CF's chromaticity domain is required to be large. However, increasing the chromaticity domain through CF countermeasures will result in the decrease of CF transmittance.Similarly, CF and polarizer contrast and transmittance are also contradictory.In terms of design, in order to obtain high-quality LCD products with low flicker and low crosspoint, it is often necessary to reduce the impedance of the distribution line by increasing the width of the pixel distribution line, which will reduce the pixel opening rate and thus reduce the transmittance.Different LCD display mode, transmittance level is different.The transmittance of IPS display mode and VA display mode is lower than that of TN display mode, but the field of view of IPS display mode and VA display mode is larger. In order to improve the field of view, TN display mode needs to adopt a high-cost compensation film.The design with low transmittance of LCD can be done conservatively. Although it has advantages in pass rate, it will increase the cost of materials, such as using DBEF and other brightening measures.
In the complex factors restricting transmittance of TFT LCD, different transmittance design countermeasures will bring different adverse effects.The designer needs to fully grasp the transmittance factors related to the LCD, in order to design the ideal TFT LCD high-light LCD products.About the LCD screen customization, selection, wide temperature and other questions and requirements, welcome to consult delsey technical staff, we will provide you with the best LCD solution.