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Research & Development CSTN LCD



 

Introduction


Liquid crystal displays have been widely used in our daily life. We can see many applications in portable and household electronic products. Because of the visual effect and the fashionable reasons, color display should be more popular than monochromatic display. Color STN-LCDs can meet our need for colorful picture display. Although the electro-optical properties of color STN-LCDs, such as contrast, viewing angle and response time, are not as good as that of color TFT-LCDs, they could still be a nice choice for those who care about the cost but do not concern about response time in video display.

Principle
The structure of color STN-LCDs, including color filter, retardation film and STN-LCD panel, is showing in Fig. 1.
 


 

 

A gray scale scheme is applied to control the transmittance of R, G, B pixels on color filter. By the different proportion of R, G, B elements, we can get many kinds of color. Additionally, we can get higher contrast and wider viewing angle on the display due to optical compensation properties of retardation film.

For handheld devices, the power-consumption is a very important issue. So several new technologies have developed for low power-consumption application. Because the backlight's power-consumption is the large part for Color STN Display, display without backlight is the best technology for low power-consumption. These new technology, named Reflective and Transflective Color STN Display, are more and more popular because of their low power-consumption. The structure of Reflective and Transflective Color STN Panel is shown as picture illustrated:
 

 

Compared with Transmissive Color STN, shown as above picture, the Al reflector is the new component in Reflective and Transflective LCD Panel.

 

Application

   Cellular Phone

   PDA

   Communication Device

   Instrument

   Digital Camera