Compensation films polycarbonate

Summary A new retarder film was developed which shows a reversible retardation change with temperature to reduce the loss of contrast of film-compensated STN-mode LCDs with increasing temperature. The film consists of polycarbonate blended with a liquid-crystalline silicone. The improvement of the LCD s contrast over a wide temperature range and the stability of the film satisfy the requirements for car equipment and other mobile applications. 

The concept of using a second layer containing LC molecules as in a DSTN display to compensate for the temperature-dependent retardation of STN cells is now applicable also to film-compensated displays. The TCR films can be produced to improve the performance of any STN display in a wide range from room temperature up to 80 °C. The durability of the TCR films is comparable to that of conventional PC retarder films. The advantage of applying the well established and reliable production process for retarder films from polycarbonate by adding a low content of LC silicone is reasonable fix)m the economic point of view also. Thus, the field of application of STN displays, especially STN for car equipment and mobile applications, is expected to be considerably expanded by using these films. 

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