We have developed a novel reflective LCD without polarizers, which is sure to provide excellent visibility (reflectance = 50%, CR = 10:1). Moreover, we have also achieved extremely low power consumption of 10 microwatts to introduce low frequency driving (less than 1Hz) without flicker and image sticking. These characteristics were realized to combine pixel memory circuit and new PNLC material. IntroductionInformation displays have widely prevailed among our daily life. That means, it demands much effort to broaden application fields of electronic displays and to develop the information society further, and therefore the importance of the low power consumption is arising more than ever. Since the power consumption of the conventional electronic displays is still high enough to limit their usage pattern or usage environment. In particular, such functions as the reflective display, the low frame rate drive and the ability to memorize images are quite effective to realize the display consuming low electric power. The display images can be memorized by using the electrophoretic display [1] or the cholesteric liquid crystal display [2], but those displays have required relatively high driving voltages and slow responses.From these viewpoints, the combination of the reflective type of liquid crystal display (RLCD) [3] and the drive scheme such as the low frame rate drive [4] or the pixel-memory circuit [5-6] should be a promising candidate. Since the power consumption of an LCD module generally depends on driving frequency, the lower the frame rate gets, the lower power the module consumes. And the pixel-memory circuit technology enables the module to have any images memorized at the pixels with the data driver suspended.An RLCD using polymer network liquid crystals (PNLC) [7] is the display system to control transmission or scattering of incoming light ray without polarizers. Its remarkable features are high light utilization efficiency due to polarizer-free system and low level of dependence on viewing angle. And a PNLC is one of solutions to realize an energy saving, paper-like display.In the meantime, a PNLC has had a couple of challenges for TFT drive, which are high driving voltage, slow response and low voltage holding ratio. However recent progress of the PNLC materials enables TFT drive of a PNLC by improving the properties above [8].Our objective is to develop an ultra low-power-consumption RLCD with excellent visibilities by using the one-bit pixel memory technology and the PNLC. PrincipleOur newly developed display is composed of the PNLC layer formed between a transparent electrode and mirror reflective pixel electrodes, and the one-bit pixel memory circuits embedded in the pixel area under the reflective mirror electrodes. Pixel Memory TechnologyThe system block diagram of our newly developed pixel memory display is shown in Figure 1. The interface of this display is very simple, because only 5 input lines are necessary for operating this display including power supplies. Timing generator with a 3-line se...

For the first time, we have developed a 60-inch diagonal size seethrough display using polymer network liquid crystal (PNLC) technology. The color display system by combination of the seethrough display and a projector enables distinguishing eye-catch effect. It creates new application of displays, such as information display, digital signage and substitution of window.

Novel reflective color LCDs without polarizers have been developed with using PDLCs and retro‐reflectors. By eliminating polarizers, brightness of our newly developed LCDs has been increased by 51% compared to conventional reflective LCDs, and there still is much room to be improved. What's more, our LCDs can be displayed not only bright text images but also color moving images on, since their response time and driving voltage are significantly fast (63ms) and low (5.5 volts).

A novel reflective color LCD without polarizer has been developed with using PDLC and retro-reflector. Bright color images including moving images are available with utilizing ambient light. Our novel LCD will create a new application area such as electronic paper.

Abstract— A novel reflective color LCD without polarizers has been developed using a PDLC film and a retro‐reflector. Bright color images including moving images are achievable with ambient light. This novel LCD will enable the new application area of electronic paper.