LCD apparatus with improved gray scale at large viewing angles and method and apparatus for driving same
AssigneeInternational Business Machines Corporation
InventorsMitsuru Ikezaki, Shunji Suzuki, Hideo Takano
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Abstract
A liquid crystal display apparatus in normally-white mode in which gray scale display is obtained by providing different applied voltages corresponding to different gray scale levels, respectively, characterized in that in a curve showing the relationship between the applied voltage and light transmittance, the lowest applied voltage is set so as to be shifted in the direction of a monotonically decreasing region of the curve. The display simultaneously provides both good contrast ratios and good gradation at large viewing angles, and gray scale is not inverted.
Claims11
In a liquid crystal display apparatus operating in normally white mode, a method for driving the liquid crystal display apparatus wherein a gray scale display is obtained by providing different applied voltages corresponding to different gray scale levels, respectively, said gray scale display having a transmittance characteristic as a function of applied voltage which monotonically decreases over a range of applied voltage, the improvement comprising:
- setting a lowest applied voltage at a value within said range, whereby gray scale inversion is avoided over a wider range of viewing angles than when said lowest applied voltage is set lower than within said range without use of a viewing angle sensor.
A normally-white mode liquid crystal display apparatus, wherein gray scale display is obtained by providing different applied voltages corresponding to different respective gray scale levels, said gray scale display having a transmittance characteristic as a function of applied voltage which monotonically decreases over a range of applied voltage, wherein the improvement comprises:
- means for setting a lowest applied voltage at a value within said range, whereby gray scale inversion is avoided over a wider range of viewing angles than when said lowest applied voltage is set lower than within said range without use of a viewing angle sensor.
In a normally-white mode liquid crystal display apparatus, including means for driving the liquid crystal display apparatus so that gray scale display is obtained by providing different applied voltages corresponding to different gray scale levels, respectively, said gray scale display having a transmittance characteristic as a function of applied voltage which monotonically decreases over a range of applied voltage, said apparatus comprising:
- an applied voltage setting means for setting a lowest applied voltage at a value within said range, whereby gray scale inversion is avoided over a wider range of viewing angles than when said lowest applied voltage is set lower than within said range without use of a viewing angle sensor.
Dependencies are inferred from the claim text.