| 摘要 |
<p>PURPOSE: To improve the contrast ratio of a twisted nematic display which operates in a dark off state by adding a second cell called as a compensation cell in series to a first liquid crystal cell. CONSTITUTION: The inside surface of a glass supporting plate 23 has the patterns of row electrodes 25 and the inside surface of a glass supporting plate 24 has the patterns of column electrodes 26. Oriented layers 27, 26 are diagonally deposited by evaporation on the glass supporting plates 23, 24 and the electrode patterns 25. The compensation cell 30 having nearly the same thickness as the thickness of a driving cell 32 is oriented just adjacently to the driving cell 21. This compensation cell 30 also packs the space between the glass supporting plates 32 and 33 and has a nematic liquid crystal material 31 in contact with the oriented layers 34, 35 formed by the diagonal vapor deposition. A polarizer 36 exists between the incident light and the driving cell 21 on the input side. An analyzer 37 exists adjacently to the output side of the compensation cell 30. The driving cell 21, then, rotates polarized light 90 deg. and the compensation cell 30 rotates this polarized light in the direction where the polarized light is returned by this angle and, therefore, a bright state is obtd. in an off state if the polarizer 36 and the analyzer 37 are arranged in parallel. The dark off state is obtd. when the polarizer 36 and the analyzer 37 are rotated relatively 90 deg.. As a result, the twisted nematic liquid crystal display of the dark off state having the improved contrast ratio is obtd.</p> |
