Grayscale shading for liquid crystal display panels
First Claim
1. A method for controlling pixel brightness levels for a digitally controlled display, comprising the steps of:
- associating a duty cycle with each of a plurality of pixel brightness levels;
periodically generating a pattern by a matrix multiplication, the pattern defying a plurality of pixel phase shifts;
applying the pattern to assign one of the phase shifts to each pixel, for energizing the pixel at a particular duty cycle;
wherein the matrix multiplication includes;
matrix multiplying a matrix by itself p times;
where p indicates a phase shift amount; and
the step of applying includes;
for each phase shift, applying a pattern corresponding to the matrix multiplied by itself p times.
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Accused Products
Abstract
An LCD controller for use e.g. in a portable computer provides gray scale shading for both monochromatic and color displays using frame rate control modulation for intensity shading for each pixel. The gray scale shading process and circuit do not require any memory for storing phase tiling matrices or frame modulation pattern sequences; both of these instead are generated in real time using a linear matrix logic structure. Use of linear matrix operations also allows generation of various phase shifts of frame modulation pattern sequences to provide a better image on the display. In addition to providing programmable 4, 8, or 16 intensity levels, the present method and apparatus provide that vertically, horizontally or diagonally adjacent pixels on the display never have the same phase in the same frame, and in addition that the pixel display drivers are uniformly loaded.
45 Citations
11 Claims
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1. A method for controlling pixel brightness levels for a digitally controlled display, comprising the steps of:
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associating a duty cycle with each of a plurality of pixel brightness levels; periodically generating a pattern by a matrix multiplication, the pattern defying a plurality of pixel phase shifts; applying the pattern to assign one of the phase shifts to each pixel, for energizing the pixel at a particular duty cycle; wherein the matrix multiplication includes; matrix multiplying a matrix by itself p times;
where p indicates a phase shift amount; andthe step of applying includes; for each phase shift, applying a pattern corresponding to the matrix multiplied by itself p times. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A controller for a digitally controlled display having a plurality of pixels, each pixel operating at a plurality of brightness levels determined by energizing each pixel for an associated duty cycle, the controller comprising:
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a clocked pattern generator, wherein the pattern generator periodically outputs a pattern signal defining one of p phases; clocked phase selection multiplexer coupled to receive each of the pattern signals and periodically select a single output pattern; wherein each pattern is applied to a signal representing a brightness level for a pixel, thereby to define a phase shift for the pixel; and means for matrix multiplying a matrix by itself p times, where p indicates a phase shift amount for a pixel, and each applied pattern corresponds to the matrix multiplied by itself p times. - View Dependent Claims (8, 9, 10, 11)
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Specification