Japan Display has developed a paper-like low-power color reflective LCD, which can display video.
“Ordinary liquid crystal displays have a backlight, and produce the picture by using a liquid crystal shutter. But this panel doesn’t have a backlight. It reflects light from above, and the liquid crystal shutter is used to produce a monochrome image. At the same time, color filters are used, to give a color picture.”
“This display has what’s called a Light Control Layer. When the display simply reflects light as usual, it looks metallic, like a mirror. When we add this layer, the display collects light to some extent, in the direction of the user’s eyes, making it look similar to paper. But the light returns efficiently in the direction of the eyes. By developing this layer, we’ve achieved good color, which couldn’t be done with ordinary digital paper. This display can show video, so we think it’ll lead to new solutions and applications.”
Japan Display has developed two versions. The first is highly reflective, with a reflection rate of 40%, and 5% coverage of the NTSC color gamut. The second has high color purity with 36% coverage of the NTSC color gamut, but its reflection rate is 28%, making it slightly dimmer. Both types have a contrast ratio of 30:1, and power consumption of 3 mW when showing still pictures.
“This display is a reflective type, but as it uses liquid crystal, it has electric circuits built in. The circuits can retain signals. This feature is called Memory in Pixels. With a still picture, once the data has been written, it can be retained, so power consumption is extremely low.”
“Here, we’re presenting two displays, a conventional version and a type with high color gamut. For the conventional version, the technology has already been proven, so we can mass-produce this right away if customers require it. The type with high color gamut still has a few issues which we need to overcome. But we would like to discuss this type with customers when the technical issues are sorted out.”