Citizen, a leading supplier of electronic products to the OEM market, has announced the development of a new type of liquid crystal display using "HyperScan" technology.

The HyperScan system improves the performance of a STN passive matrix display to a level rivalling that of active matrix screens. The high response speed, improved viewing angle and impressive contrast ratio mean that in comparative tests against similar size active screens, many choose the HyperScan display.

In a similar way to consumer televisions with "100Hz technology", the new HyperScan video modules use twice the usual scanning frequency to dramatically increase the image quality. Within a 50Hz PAL display, a "video frame-store" is used to give a 100Hz frame frequency. With the every decreasing price of memory required for the frame-store, it is now possible to produce a competitive display using this technology.

"Voltage Level Sliding", an optimised driving scheme, is used to control the potential difference across the cells. In a standard display, each row is simply "enabled" and the image signals are sent down the column electrodes. In Citizen's voltage level sliding system, a negative voltage is applied to each row of the display as it is selected, and a smaller image signal is applied to the column electrodes.

A 5.8-inch television is the first HyperScan (HPS) technology display to be produced in volume and will be supplied in NTSC format for the Japanese and American markets, with PAL (European) versions available shortly. Its specification shows an impressive contrast ratio of 40:1, response speeds of less than 90ms and a screen brightness of 300 Cd/m2 with a resolution of 960 (RGB) x 220 pixels.

Mark Beauchamp, LCD Product Manager at Citizen, comments: "HyperScan emphasises Citizen's commitment to developing new techniques in the LCD arena. This new product also shows that passive screen technology can compete head-on with active displays in most applications"

"Citizen have been a leader in miniaturisation of displays and other components and it is natural that we should concentrate our efforts on displays for portable and hand-held applications such as our small, colour VGA screens."