Gray level addressing for LCDs
First Claim
1. A method for addressing a passive flat panel display in which a plurality of overlapping first and second electrodes on opposite sides of an electro-optical material define a matrix of pixels that display in a frame period information in more than two gray levels, the display being characterized in that the optical state of each pixel is determined by the rms voltage appearing across the pixel over the frame period, the method comprising:
- applying first signals that are independent of the information to be displayed to the first electrodes during characteristic time intervals of each frame period;
applying second signals of changing pulse height magnitudes and representative of the information to be displayed to the second electrodes during each frame period, the magnitude of each second signal at any time being chosen from more than two available voltages and being related to the desired gray level of at least one pixel defined by the corresponding second electrode and selected one or ones of the first electrodes.
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Abstract
Method and apparatus for providing gray level addressing for passive liquid crystal display (LCD) panels having overlapping row and column electrodes defining pixels are disclosed. Depending upon whether the rows are being addressed by "standard" or "Swift" addressing, the signals for applying to the column electrodes are determined by different calculations, in all of which modes the amplitudes of the column signals are related to the gray level desired to be displayed by the individual pixels. For a split interval system, column signals of appropriate amplitude and polarity are applied during different subintervals of a characteristic time interval of the display panel depending upon the method of addressing the rows. In the full interval mode, the column signals applied over a full time interval are based on the desired gray level of all the pixels in the column, adjusted to provide the proper rms voltage across all the pixels so that they display the desired gray levels.
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Citations
37 Claims
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1. A method for addressing a passive flat panel display in which a plurality of overlapping first and second electrodes on opposite sides of an electro-optical material define a matrix of pixels that display in a frame period information in more than two gray levels, the display being characterized in that the optical state of each pixel is determined by the rms voltage appearing across the pixel over the frame period, the method comprising:
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applying first signals that are independent of the information to be displayed to the first electrodes during characteristic time intervals of each frame period; applying second signals of changing pulse height magnitudes and representative of the information to be displayed to the second electrodes during each frame period, the magnitude of each second signal at any time being chosen from more than two available voltages and being related to the desired gray level of at least one pixel defined by the corresponding second electrode and selected one or ones of the first electrodes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A method for addressing a passive flat panel display in which a plurality of overlapping first and second electrodes on opposite sides of an electro-optical material define a matrix of pixels that display in a frame period information in more than two gray levels, the display being characterized in that the optical state of each pixel is determined by the rms voltage appearing across the pixel over the frame period, the method comprising:
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generating a series of first signals that are independent of the information to be displayed; applying the first signals to the first electrodes during characteristic time intervals of each frame period; generating a series of second signals of changing pulse height magnitudes and representative of the information to be displayed; applying the second signals to the second electrodes during the characteristic time intervals of each frame period; the magnitudes of the second signals at any time during a characteristic time interval being chosen from more than two available voltages and being related to the desired gray level of at least one pixel defined by the corresponding second electrode.
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30. Apparatus for addressing a passive flat panel display in which a plurality of overlapping first and second electrodes on opposite sides of an electro-optical material define a matrix of pixels that display information in a more than two gray levels, the display being characterized in that the optical state of each pixel is determined by the rms voltage appearing across the pixel over the frame period, the apparatus comprising:
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means for driving the first electrodes during characteristic time intervals of each frame period with first signals which are independent of the information to be displayed; and means for driving the second electrodes during each frame period with second signals, each of which is representative of the information to be displayed and whose pulse height amplitude at any time is chosen from more than two available voltages and is related to the desired gray level of at least one of the pixels defined by the second electrode.
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31. Apparatus for converting video signals including control components and information components into signals for addressing a passive flat panel display in which a plurality of overlapping first and second electrodes on opposite sides of electro-optical material define a matrix of pixels that display information in more than two gray levels, the display being characterized in that the optical state of each pixel is determined by the rms voltage appearing across the pixel over the frame period, the apparatus comprising:
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first signal generating means for generating a series of first signals which are independent of the information component of the video signals; means for applying the first signals to the first electrodes during characteristic time intervals of each frame period; second signal generating means for generating during subintervals of the characteristic time intervals second signals of changing pulse height magnitude selected from more than two available voltages and representative of the information component of the video signals including gray levels and the amplitude of each of which at any time is related to the desired gray level of at least one of the pixels; means for applying the second signals to the second electrodes during each frame period coincidentally with the application of the first signals to the first electrodes. - View Dependent Claims (32, 33, 34, 35, 36, 37)
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Specification