Improvement of multiplexability of double-layered homogeneously oriented nematic LCD by simultaneous driving method
In: Electronics and Communications in Japan (Part II: Electronics), Jg. 74 (1991), S. 49-58
Online
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Zugriff:
A new driving method (double-layer simultaneous driving method) is proposed to improve the time multiplexability of compensation-type homogeneously oriented LCDs by stacking two homogeneously oriented simple matrix LCDs. The experimental results also are shown. Two cells (cell A and cell B) are made of the same LCD material and with the same amount of Δnd. These cells are stacked so that the projected directions of the optical axes onto the electrode surface are perpendicular to each other. By this method, an optical compensation effect can be obtained, and it has enabled good black-and-white display. Whereas in the conventional method only one of the two cells is biased, two cells in the proposed double-layer simultaneous driving method are time-multiplexed by the optimized bias method with the same duty ratio. During the nonselect state, the rms voltage of VAB = (Vth · VT max)1/2 is applied. By contrast, during the select state, the rms voltages of VA = K · VAB/K are applied to cell A and cell B, respectively. Here, Vth is the threshold voltage, VT max is the rms voltage at which the transmission takes the first maximum in the V-T curve during the normally black mode (or the voltage at which the transmission takes the first minimum during the normally white mode), and K indicates {(N1/2 + 1)/(N1/2 – 1)}1/2 where N is the number of scanning lines. It has been confirmed that the contrast ratio is improved to 7.5 by the double-layer simultaneous driving method when the contrast ratio is only 1 when a single layer is driven with the 1/500 duty ratio. Furthermore, the viewing angle characteristics also are improved compared to those of the conventional compensation-type single-layer driving method.
Titel: |
Improvement of multiplexability of double-layered homogeneously oriented nematic LCD by simultaneous driving method
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Autor/in / Beteiligte Person: | Takahashi, Taiju ; Saito, Susumu |
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Zeitschrift: | Electronics and Communications in Japan (Part II: Electronics), Jg. 74 (1991), S. 49-58 |
Veröffentlichung: | Wiley, 1991 |
Medientyp: | unknown |
ISSN: | 1520-6432 (print) ; 8756-663X (print) |
DOI: | 10.1002/ecjb.4420741205 |
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