LONDON Researchers at the University of Strathclyde, Scotland, have developed a reflective bistable liquid crystal display (LCD) that can maintain static images in full daylight without requiring an external power supply. The University is looking to license the technology and says a major application would be solar powered display advertisements, as well as mobile phones, laptop PCs, ATMs, electronic paper, smart cards and disposable displays.
Specifically, the University is seeking a partner with expertise in interdigitive electrodes to help take the technology to market.
The prototypes under development have been proven to be truly bistable and suitable for production using a roll to roll print process, a low cost technique that to date has not been used never used for making LCDs.
The technology is said to incorporate reflective display units which are both flexible and extremely tough, making them ideal for outdoor screens in any shape. Being bistable they only require power to change the image presented and, overall, offers such a significant energy advantage over traditional electronic displays.
An important portion of the unit's power saving comes from the fact that, in addition to being bi-stable, the display is highly reflective and thus does not require the large backlight – which consumes much of the power of a traditional electronic display.
The manufacturing technique used replaces the continuous layer of liquid crystal in a standard device with a polymer substructure with the ability to micro-confine the liquid crystal into discrete wells.
The shape and surface properties of the polymer and
the presence of high-distortion regions create multi-stable states. These are optically differentiable and can represent levels of grey from black to white. Switching between states can be achieved using in-plane electrodes.
In each of the stable states the average liquid crystal molecular direction remains in the plane of the bounding surfaces.