Patent US5585816A successfully refreshed from Google Patents.
US5585816A
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Displaying gray shades on display panel implemented with active addressing technique
Assignee: Infocus Corp
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Filing: 1995-06-06
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Granted: 1996-12-17
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Expires: 2015-06-06
Abstract
Abstract Different gray shades or hues may be displayed in accordance with an active addressing technique that addresses faster responding passive matrix liquid crystal display panels (LCDs) so that video rate, high information content LCDs are perceived as having improved contrast by limiting peak voltage levels across the pixels. A preferred embodiment of the active addressing technique is implemented such that a first set of LCD electrodes is continuously driven with signals each comprising a train of pulses that are periodic in time, have a common period T, are independent of the information to be displayed, and are preferably orthonormal. Multiple column signals are generated from the collective information states of the pixels defined by the overlap with a second electrode pattern. Each column signal is proportional to the sum, obtained by considering each pixel in the column, of the exclusive-or (XOR) products of the logic level of the amplitude of each row signal times the logic level of the information state of the pixel corresponding to that row. Two alternative gray shading techniques provide for intermediate optical states between light and dark states. A frame modulation technique uses several frame periods to control the proportion of time a pixel is light or dark. A pulse width modulation technique subdivides an addressing time interval to control the proportion of time a pixel is light or dark during the addressing time interval. Either technique addresses the pixel to an intermediate optical state.
Inventors
- 👤 Terry J. Scheffer
- 👤 Benjamin R. Clifton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 05:19
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/36; G09G3/3611; G09G3/3622; G09G3/3625; G09G3/2007; G09G3/2011; G09G3/2014; G09G3/2018; G09G3/2022
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
316 words
A method for addressing a display panel to display different gray shades or hues, the display panel including overlapping first and second electrodes positioned on opposite sides of an rms-responding material to define an array of pixels that display arbitrary information patterns that depend on values of rms voltages established across the pixels and correspond to pixel input data, each pixel input datum having first and second logic levels that represent corresponding first and second optical transmission states for the pixel to which the pixel input datum corresponds, the method comprising: applying first signals to corresponding first electrodes during a frame period that is divided into time intervals, the first signals having amplitudes, and multiple ones of the first signals causing multiple selections of the corresponding first electrodes, the multiple selections being distributed over the frame period; each of the first signals provides a number of the time intervals over the frame period that is less than an exponential function of the number of first electrodes; controlling for each pixel a length of time the pixel input datum is in the first logic level and a length of time the pixel input datum of the pixel is in the second logic level; and generating second signals and applying them to corresponding ones of the second electrodes, the second signals having amplitudes determined by the amplitudes of more than one of the first signals causing selections and by the logic levels of the pixel input data of pixels defined by the corresponding first electrodes, the length of time the pixel input datum associated with a pixel is in the first logic level as compared with the length of time the pixel input datum associated with the pixel is in the second logic level producing for the pixel an intermediate optical transmission state between the first and second optical transmission states and corresponding to an intermediate gray shade.
Claim 2
Independent Claim
316 words
A method for addressing a display panel to display different gray shades or hues, the display panel including overlapping first and second electrodes positioned on opposite sides of an rms-responding material to define an array of pixels that display arbitrary information patterns that depend on values of rms voltages established across the pixels and correspond to pixel input data, each pixel input datum having first and second logic levels that represent corresponding first and second optical transmission states for the pixel to which the pixel input datum corresponds, the method comprising: applying first signals to corresponding first electrodes during a frame period that is divided into time intervals, the first signals having amplitudes, and multiple ones of the first signals causing multiple selections of the corresponding first electrodes, the multiple selections being distributed over the frame period; each of the first signals provides a number of the time intervals over the frame period that is less than an exponential function of the number of first electrodes; controlling for each pixel a length of time the pixel input datum is in the first logic level and a length of time the pixel input datum of the pixel is in the second logic level; and generating second signals and applying them to corresponding ones of the second electrodes, the second signals having amplitudes determined by the amplitudes of more than one of the first signals causing selections and by the logic levels of the pixel input data of pixels defined by the corresponding first electrodes, the length of time the pixel input datum associated with a pixel is in the first logic level as compared with the length of time the pixel input datum associated with the pixel is in the second logic level producing for the pixel an intermediate optical transmission state between the first and second optical transmission states and corresponding to an intermediate gray shade.
Claim 3
Dependent Claim
68 words
The method of claim 1 in which the controlling for each pixel the lengths of time the pixel input datum is in the first and second logic levels further comprises: determining binary pixel information states corresponding to multiple subintervals of a time interval; and controlling the ratio of the number of subintervals of a time interval the pixel input datum is in the first and second logic levels.
Claim 4
Dependent Claim
14 words
The method of claim 2 in which the multiple subintervals are of equal duration.
Claim 5
Dependent Claim
14 words
The method of claim 2 in which the multiple subintervals are of unequal durations.
Claim 6
Dependent Claim
24 words
The method of claim 2 in which the generating of second signals includes generating a second signal for each subinterval of the time interval.
Claim 7
Dependent Claim
81 words
The method of claim 2 in which the binary pixel information states associated with a pixel and corresponding to the multiple subintervals comprise a multi-bit gray level word for the pixel and in which the amplitude of the second signal at a particular time interval is determined by the amplitudes of more than one of the first signals at the particular time interval and by individual bits of the multi-bit gray level words of pixels defined by the corresponding first electrodes.
Claim 8
Dependent Claim
50 words
The method of claim 6 in which the amplitude of the second signal at the particular time interval is proportional to the sum of the products of the bits of the multi-bit gray level word and the amplitudes of the first signals of pixels defined by the corresponding first electrode.
Claim 9
Dependent Claim
49 words
The method of claim 6 in which the amplitude of the second signal at the particular time interval is proportional to exclusive-OR products of individual bits from each of the multi-bit gray level words and the amplitudes of the first signals of pixels defined by the corresponding first electrode.
Claim 10
Dependent Claim
66 words
The method of claim 1 in which the controlling for each pixel the lengths of time the pixel input datum is in the first and second logic levels further comprises: determining binary pixel information states corresponding to multiple frame periods; and controlling the number of frame periods for which the binary pixel information states produce display information patterns that include at least one intermediate gray shade.
Claim 11
Dependent Claim
26 words
The method of claim 9 in which the determining binary pixel information states includes determining binary pixel states corresponding to multiple subintervals of a time interval.
Claim 12
Dependent Claim
81 words
The method of claim 10 in which the binary pixel information states associated with a pixel and corresponding to the multiple sub-intervals comprise a multi-bit gray level word for the pixel and in which the amplitude of the second signal at a particular time interval is determined by the amplitudes of more than one of the first signals at the particular time interval and by individual bits of the multi-bit gray level words of pixels defined by the corresponding first electrodes.
Claim 13
Dependent Claim
48 words
The method of claim 11 in which the amplitude of the second signal at the particular time interval is proportional to exclusive-OR products of individual bits-from each of the multi-bit gray level words and the amplitudes of the first signals of pixels defined by the corresponding first electrode.
Claim 14
Dependent Claim
50 words
The method of claim 9 in which the amplitude of the second signal at the particular time interval is proportional to the sum of the products of the bits of the multi-bit gray level word and the amplitudes of the first signals of pixels defined by the corresponding first electrode.
Claim 15
Independent Claim
288 words
A system for addressing a display panel to display different gray shades or hues, the display panel including overlapping first and second electrodes positioned on opposite sides of an rms-responding material to define an array of pixels that display arbitrary information patterns that depend on values of rms voltages established across the pixels and correspond to pixel input data, each pixel input datum having first and second logic levels that represent corresponding first and second optical transmission states for the pixel to which the pixel input datum corresponds, the system comprising: a first signal generator for generating and applying first signals to corresponding first electrodes during a frame period that is divided into time intervals, the first signals having amplitudes, and multiple ones of the first signals causing multiple selections of the corresponding first electrodes, the multiple selections being distributed over the frame period; each of the first signals provides a number of the time intervals over the frame period that is less than an exponential function of the number of first electrodes; and a second signal generator for generating and applying second signals to the second electrodes, the second signal generator including a correlator and a gray shade controller, the correlator correlating the amplitudes of the first signals and the pixel input data to determine the amplitudes of the second signals and the gray shade controller controlling for each pixel a length of time the pixel input datum is in the first logic level and a length of time the pixel input datum of the pixel is in the second logic level to produce for the pixel an intermediate optical transmission state between the first and second optical transmission states and corresponding to an intermediate gray shade.
Claim 16
Independent Claim
288 words
A system for addressing a display panel to display different gray shades or hues, the display panel including overlapping first and second electrodes positioned on opposite sides of an rms-responding material to define an array of pixels that display arbitrary information patterns that depend on values of rms voltages established across the pixels and correspond to pixel input data, each pixel input datum having first and second logic levels that represent corresponding first and second optical transmission states for the pixel to which the pixel input datum corresponds, the system comprising: a first signal generator for generating and applying first signals to corresponding first electrodes during a frame period that is divided into time intervals, the first signals having amplitudes, and multiple ones of the first signals causing multiple selections of the corresponding first electrodes, the multiple selections being distributed over the frame period; each of the first signals provides a number of the time intervals over the frame period that is less than an exponential function of the number of first electrodes; and a second signal generator for generating and applying second signals to the second electrodes, the second signal generator including a correlator and a gray shade controller, the correlator correlating the amplitudes of the first signals and the pixel input data to determine the amplitudes of the second signals and the gray shade controller controlling for each pixel a length of time the pixel input datum is in the first logic level and a length of time the pixel input datum of the pixel is in the second logic level to produce for the pixel an intermediate optical transmission state between the first and second optical transmission states and corresponding to an intermediate gray shade.
Claim 17
Dependent Claim
76 words
The system of claim 14 in which the gray shade controller further comprises means for causing a pixel to display an intermediate optical transmission state between the first and second optical transmission states by controlling in each time interval the length of time the pixel input datum of the pixel is in the first logic level as compared with the length of time the pixel input datum of the pixel is in the second logic level.
Claim 18
Dependent Claim
82 words
The apparatus of claim 14 in which the gray shade controller further comprises means for causing a pixel to display an intermediate optical transmission state between the first and second optical transmission states by controlling the length of time the pixel input datum of the pixel is in the first logic level as compared with the length of time the pixel input datum of the pixel is in the second logic level over the duration of a plurality of successive frame periods.
References Cited (Backward Citations)
US3668639A
Cited
US3955187A
Cited
US3997719A
Cited
US4043640A
Cited
US4127848A
Cited
US4060801A
Cited
US4253096A
Cited
JPS5422856A
Cited
US4227193A
Cited
US4250503A
Cited
US4203104A
Cited
CH620036A5
Cited
US4380008A
Cited
US4317115A
Cited
US4346378A
Cited
CH645473A5
Cited
US4510444A
Cited
US4560982A
Cited
US4427978A
Cited
US4496219A
Cited
US4508427A
Cited
US4630122A
Cited
US4506955A
Cited
EP0127701A1
Cited
US4824211A
Cited
US4709995A
Cited
US4800382A
Cited
US4752774A
Cited
US5010327A
Cited
US4818078A
Cited
US4808991A
Cited
US4743096A
Cited
US4769713A
Cited
US5189406A
Cited
US5055833A
Cited
US4766430A
Cited
US4840462A
Cited
US4857906A
Cited
US4840460A
Cited
US5062001A
Cited
US4991022A
Cited
US5134495A
Cited
US5155447A
Cited
US5420604A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-12-17 | 2000-06-17 | 2000-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-12-17 | 2004-06-17 | 2004-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-12-17 | 2008-06-17 | 2008-12-17 | $7700.00 | Window Closed / Lapsed |