Tuesday, 4 July 2006 - 12:00 AM
DEVIP-68

Passive matrix liquid crystal display with internal volume electrodes

Sergey Studentsov, Liquid Crystal Research and Production, Research and Development Institute "Volga", Prospect 50-let Octyabrya 101, Saratov, Russia, Vladimir A. Brezhnev, Liquid Crystal Research&Production, Research&Development Institute, Prospect 50-let Octyabrya 101, Saratov, Russia, Vladimir Chigrinov, Electrical and Electronic Engineering, Hong Kong University of Science and Technology, EEE Department , The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, Hong Kong, Hong Kong, and Alexander Muravsky, Department of Electrical and Electronic Engineering, HKUST, Center for Display Research, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, Hong Kong.

PASSIVE MATRIX LIQUID CRYSTAL DISPLAY with INTERNAL VOLUME ELECTRODES

 

Studentsov S.A., Brezhnev V.A.

Research & Development Institute “Volga”, Saratov, Russia

Chigrinov V.G., Murauski Al.

Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong

Thin ITO films on glass surface are usually used as electrodes in liquid crystal displays (LCDs). This leads to a charge accumulation on “off-state” pixels in passive matrix LCDs. As a result of it the multiplex level is limited, electro-optical parameters are worsened and the power consumption is decreased.

Multi-layer 3D electrodes, consisted of conventional electrode on the substrate surface and additional electrode system, which includes conducting film on isolating pedestal tops is discussed in this paper. Those pedestals are placed between the surface electrode rows or columns like a black mask. The pedestal value is equal to 1/4 - 1/2 of the LC-layer thickness. The LC cell transmittance varies with voltage, applied to both electrodes of one substrate, as for In-Plane-Switching. The root-mean-square voltage on “off-state” pixels can be reduced by the electrical signal control on additional electrodes. So, the multiplex level or contrast ratio for passive matrix addressing of LCD is increased.

The standard alignment methods (rubbing or oblique evaporation) are useless for the special 3D electrode structures described. The new LC alignment non-defect technology for 3D electrodes is suggested and discussed in this paper.

Various variants of 3D electrode construction are proposed.

The support from grant ITF ITS/111/03 is acknowledged.

 

                    a)                                                                         b)

Figure 1. Passive matrix addressing of LC cell with 3D electrodes.

a). The contrast ratio for direct drive is equal to 228:1, reaction time – about 1.1-1.3 ms, relaxation time – 18-19 ms;

b). Single-element-prototype with contrast ratio more than 200:1, total response time less than 90 ms at 1/64 multiplex voltage form is presented.

 


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