With ECB technology, two different display modes are implemented within one LCD cell. The single pixel is divided into two areas, a reflective and a transmissive part. This allows optimal design for the different operating conditions, from direct sunlight to night operation. The split ratio between the reflective and transmissive areas can be controlled for customer-specific displays, optimized to the application.

Easy to read from
different viewing angles

The transmissive part of the cell corresponds to the conventional TFT design with an RGB color filter. The liquid crystal is arranged as in a TN cell. The light from the backlight is modulated by the cell. This results in high color saturation (NTSC: > 50 percent) and high contrast of typ. 200:1 in this area (Image 2). In the transflective part of the cell, a metallic reflective layer is implemented in conjunction with an optically modulated compensation layer in the form of microlenses.
Ambient light passes through the optical path twice. Thus, good color saturation values and contrasts are achieved (Image 3). The integrated lens modulation guarantees good readability under different viewing angles.
Since the viewer always perceives the entire cell area, the contrast and color saturation values are average. They are generated from the two cell areas. This results in color saturation values of typ. 6 percent in reflective mode and typ. 18 percent in transmissive mode. The contrast values also behave similarly: from 6:1 to 35:1. ▪ ds