Method and apparatus for displaying different shades of gray on a liquid crystal display
First Claim
1. A display control system for producing an optical gray-scale image on a display device having an array of display elements each providing a first or a second optical state in response to a first or a second signal level, respectively, the array of display elements having a plurality of rows and a plurality of columns, the system comprising:
- means for generating respective display signals for the display elements for producing a gray-scale image of a specified color, the display signals comprising digital signals each having a pattern of bits respectively corresponding to the first or the second signal level, a predefined pattern cycle and a duty cycle or average duty cycle related to the optical gray-scale of the image at the position of the respective display element, the duty cycle being determined over one or more of the predefined pattern cycle, the pattern of bits of each one of the digital signals being repetitively generated, the means for generating display signals providing successive bits of the display signals for respective display elements in successive timeframes, in each timeframe one bit of each of the display signals being provided in sequence for consecutive display elements in each row from a first to a last display element of the row and for consecutive rows beginning at a first row and ending at a last row of the array, and causing a predetermined skewing of each subsequently generated display signal having a pattern cycle which is an exact divisor of the total number of display elements in a row each time a bit of a respective display signal is provided for the last display element of a row, and causing a predetermined skewing of each subsequently generated display signal having a pattern cycle or a submultiple thereof which is an exact divisor of the total number of display elements in the array each time a bit of a respective display signal is provided for the last display element of the last row of the array.
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Accused Products
Abstract
A method and apparatus are disclosed which provide a means for both spatially and temporarily resolving the on/off states of a two-state display device such as a liquid crystal display to provide apparent shades of gray. A particular feature of this method is that the cycling between on and off states is not performed in a single, repetitive pattern. Rather, a pattern is utilized which repeats only after many cycles. Additionally, when the 10 method disclosed herein is utilized, adjacent pixels, when selected to display the same shade of gray, do not cycle on and off in synchronization, but rather utilize out-of-phase cycling patterns. This spatial resolution reduces perceived flicker in the display and provides a more stable image. In one embodiment, sixteen shades of gray are provided. The shades are generated by cycling individual pixels such that when averaged over time, the duty cycles of such cycling are 0, 1/9, 1/7, 1/5, 2/7, 1/3, 2/5, 7/15, 8/15, 3/5, 2/3, 5/7, 4/5, 6/7, 8/9 and 1.
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Citations
15 Claims
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1. A display control system for producing an optical gray-scale image on a display device having an array of display elements each providing a first or a second optical state in response to a first or a second signal level, respectively, the array of display elements having a plurality of rows and a plurality of columns, the system comprising:
means for generating respective display signals for the display elements for producing a gray-scale image of a specified color, the display signals comprising digital signals each having a pattern of bits respectively corresponding to the first or the second signal level, a predefined pattern cycle and a duty cycle or average duty cycle related to the optical gray-scale of the image at the position of the respective display element, the duty cycle being determined over one or more of the predefined pattern cycle, the pattern of bits of each one of the digital signals being repetitively generated, the means for generating display signals providing successive bits of the display signals for respective display elements in successive timeframes, in each timeframe one bit of each of the display signals being provided in sequence for consecutive display elements in each row from a first to a last display element of the row and for consecutive rows beginning at a first row and ending at a last row of the array, and causing a predetermined skewing of each subsequently generated display signal having a pattern cycle which is an exact divisor of the total number of display elements in a row each time a bit of a respective display signal is provided for the last display element of a row, and causing a predetermined skewing of each subsequently generated display signal having a pattern cycle or a submultiple thereof which is an exact divisor of the total number of display elements in the array each time a bit of a respective display signal is provided for the last display element of the last row of the array. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for driving a display device having a multiplicity of display elements each providing a first or a second optical state in response to a first or a second signal level, respectively, to produce an optical gray-scale image, the display elements being disposed in an array having a plurality of rows and a plurality of columns, the method comprising the steps of:
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generating respective display signals for the display elements for producing a gray-scale image of a specified color, the display signals comprising digital signals each having a pattern of bits respectively corresponding to the first or the second signal level and having a predefined pattern cycle and a duty cycle related to the optical gray-scale of the image at the position of the respective display element, the duty cycle being determined over one or more of the predefined pattern cycle the pattern of bits of each one of the digital signals being repetitively generated; providing successive bits of the display signals for the display elements in successive timeframes, in each timeframe one bit of each of the display signals being provided in sequence for consecutive display elements in each row from a first to a last display element of the row, and for consecutive rows beginning at a first row and ending at a last row of the array; causing a predetermined skewing of each subsequently generated display signal having a pattern cycle which is an exact divisor of the total number of display elements in a row each time a bit of a respective display signal is provided for the last display element of a row; and causing a predetermined skewing of each subsequently generated display signal having a pattern cycle or a submultiple thereof which is an exact divisor of the total number of display elements in the array each time a bit of a respective display signal is provided for the last display element of the last row of the array, whereby in successive timeframes adjacent display elements in each row of the array are provided with different sequences of the first and the second signal levels, and adjacent display elements in each column of the array are provided with different sequences of the first and the second signal levels. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification