Split interval gray level addressing for LCDs

Claim 3

The method of claim 1 in which the subintervals are of approximately equal durations.

Claim 4

The method of claim 1 in which the first signals are of unchanging magnitude within the characteristic time intervals.

Claim 7

The method of claim 4, in which the first signals select each first electrode during more than one characteristic time interval over each frame period.

Claim 8

The method of claim 5, in which the characteristic time intervals are divided into two subintervals and the durations of the two subintervals are approximately equal.

Claim 13

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 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: 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, the first signals selecting at least some of the first electrodes during multiple characteristic time intervals of each frame period; and means for driving the second electrodes during subintervals of the characteristic time intervals with second signals, each of which are representative of the information to be displayed and whose amplitude during each subinterval is related by a different relationship to the desired gray level of at least one of the pixels defined by the second electrode.

Claim 14

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 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: 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, the first signals selecting at least some of the first electrodes during multiple characteristic time intervals of each frame period; and means for driving the second electrodes during subintervals of the characteristic time intervals with second signals, each of which are representative of the information to be displayed and whose amplitude during each subinterval is related by a different relationship to the desired gray level of at least one of the pixels defined by the second electrode.

Claim 15

The apparatus of claim 9, in which the means for driving the second electrodes are capable of delivering signals of at least three distinct levels.

Claim 16

Apparatus for converting video signals including control 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: first signal generating means for generating a series of first signals which are independent of the information component of the video signals and which select at least some of the first electrodes during multiple characteristic time intervals of each frame period; 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 magnitude and representative of the information component of the video signals including gray levels and the amplitude of each of which at any time during each of the subintervals of a characteristic time interval is related through a different relationship 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.

Claim 17

Apparatus for converting video signals including control 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: first signal generating means for generating a series of first signals which are independent of the information component of the video signals and which select at least some of the first electrodes during multiple characteristic time intervals of each frame period; 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 magnitude and representative of the information component of the video signals including gray levels and the amplitude of each of which at any time during each of the subintervals of a characteristic time interval is related through a different relationship 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.

Claim 18

The apparatus of claim 11, including: control signal generating means for generating control signals related to the control components of the video signals, the means for applying the first and second signals to their respective electrodes being controlled by the control signal generating means.

Claim 19

The apparatus of claim 4, in which: the second signal generating means includes means for generating second signals of different amplitudes during each subinterval of a characteristic time interval of a frame period; and the means for applying the second signals applies to the second electrode second signals having different amplitudes during different subintervals of the time intervals.

Claim 20

The apparatus of claim 3, in which the first signal generating means generates first signals that select each first electrode more than once during a frame period.

Claim 21

The apparatus of claim 14 in which the selections are distributed throughout the frame period.

Claim 22

The apparatus of claim 14 in which the first signals are of unchanging magnitudes within a characteristic time interval and the second signals are of unchanging magnitudes over the subintervals of the characteristic time interval.

Claim 23

Apparatus for converting video signals including control 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 desired gray levels of the pixels being represented by pixel information elements, 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: first signal generating means for generating a series of first signals that are independent of the information component of the video signals and that are orthonormal functions selecting each first electrode more than once during a frame period; 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 magnitude and representative of the information component of the video signals including and the amplitude of each of which at any time during each of the subintervals of a characteristic time interval is related through a different relationship to the desired gray level of at least one of the pixels, the second signal generating means includes dot product generating means for generating a dot product term of each first signal and the corresponding bit plane of the pixel information element; and 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.

Claim 24

Apparatus for converting video signals including control 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 desired gray levels of the pixels being represented by pixel information elements, 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: first signal generating means for generating a series of first signals that are independent of the information component of the video signals and that are orthonormal functions selecting each first electrode more than once during a frame period; 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 magnitude and representative of the information component of the video signals including and the amplitude of each of which at any time during each of the subintervals of a characteristic time interval is related through a different relationship to the desired gray level of at least one of the pixels, the second signal generating means includes dot product generating means for generating a dot product term of each first signal and the corresponding bit plane of the pixel information element; and 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.

Claim 27

The method of claim 18, in which the magnitudes of the second signals during first and second subintervals are determined by adding and subtracting from a first order term including a gray level of a pixel defined by a selected first electrode a square root term including the gray level squared.

Claim 28

The method of claim 18 in which the subintervals are of equal duration.

Claim 29

The method of claim 18 in which the first signals select the corresponding first electrodes during multiple characteristic time intervals distributed throughout the frame period.

Claim 32

The method of claim 22 in which the subintervals are of equal duration.

Claim 33

The method of claim 22 in which the first signals select the corresponding first electrodes during multiple characteristic time intervals distributed throughout the frame period.

Claim 34

The apparatus of claim 22 in which the first signals are constant during a characteristic time interval and the second signals are constant over the subintervals of the characteristic time interval.

Claim 35

The method of claim 22, in which the magnitudes of the second signals during first and second subintervals are determined by adding and subtracting from a first order term including a gray level of a pixel defined by a selected first electrode a square root term including the gray level squared.

Claim 38

The method of claim 27 in which the subintervals are of equal duration.

Claim 39

The apparatus of claim 27 in which the first signals select the corresponding first electrodes during multiple characteristic time intervals distributed throughout the frame period.

Claim 40

The apparatus of claim 27 in which the first signals are constant during a characteristic time interval and the second signals are constant over the subintervals of the characteristic time interval.

Claim 45

The method of claim 32 in which the subintervals are of equal duration.

Claim 46

The apparatus of claim 32 in which the selections are distributed throughout the frame period.

Claim 47

The apparatus of claim 32 in which the first signals are constant during a characteristic time interval and the second signals are constant over the subintervals of the characteristic time interval.

Claim 50

The method of claim 36 in which the magnitudes of the second signals in the first and second subintervals provide across each pixel during each characteristic time interval an rms voltage that is the same as that provided by: representing the gray level of each pixel by a gray level word; dividing a characteristic time interval into progressively wider subintervals, each progressively wider subinterval associated with a progressively more significant bit of the gray level word; determining a magnitude for each second signal for each of the progressively wider subintervals, the magnitude of the second signal during each of the progressively wider subintervals being determined by the values of the corresponding bits of the gray level words of pixels defined by the corresponding second electrode and selected ones of the first electrodes.