US6414664B1
Expired / Lapsed
US
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Method of and apparatus for controlling contrast of liquid crystal displays while receiving large dynamic range video
Assignee: Honeywell Inc
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Filing: 1997-11-13
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Granted: 2002-07-02
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Expires: 2017-11-13
Abstract
Abstract An apparatus and method for controlling contrast for a liquid crystal display (“LCD”), especially active-matrix LCDs, while receiving large dynamic range video data to be displayed to the user by the LCD. Contrast settings of the LCD correspond to a single look-up table from a set of different and multiple look-up tables rather than using the contrast setting of the LCD to select different voltage values from a single look-up table. The values of the reference voltages of the LCD are varied so that all shades of gray are available with each contrast selection resulting in a high image quality and a high contrast.
Inventors
- 👤 Kurt M. Conover
- 👤 Teddy J. Wood
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 16:10
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/36; G09G2320/00; G09G2320/04; G09G2320/041; G09G2320/06; G09G2320/0606; G09G2320/066; G09G2320/0673; G09G2320/068; G09G3/2007; G09G3/3611; G09G3/3648
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
201 words
A method for controlling contrast in a liquid crystal display (“LCD”) device in which a full gray scale comprising minimum light out to maximum light out is used with variable video signal input ranges, with each video signal input range comprising a fraction of a total range of zero to full amplitude to be displayed by the LCD device, the full gray scale having a finite number of shades of gray, the LCD device having a contrast control for input by a user, the LCD device communicating with a drive voltage generator that supplies drive voltages V to the LCD device corresponding to the video signal input and a user contrast control setting, the method comprising the steps of: providing a plurality of look-up tables, the plurality of look-up tables representing a plurality of contrast settings of the LCD device; and selecting a single look-up table from the plurality of look-up tables in response to the contrast control setting selected by the user from the plurality of contrast settings through the contrast control device to affect a transfer function of the LCD device, the single look-up table containing all shade of gray available on the gray scale with each contrast setting.
Claim 2
Independent Claim
201 words
A method for controlling contrast in a liquid crystal display (“LCD”) device in which a full gray scale comprising minimum light out to maximum light out is used with variable video signal input ranges, with each video signal input range comprising a fraction of a total range of zero to full amplitude to be displayed by the LCD device, the full gray scale having a finite number of shades of gray, the LCD device having a contrast control for input by a user, the LCD device communicating with a drive voltage generator that supplies drive voltages V to the LCD device corresponding to the video signal input and a user contrast control setting, the method comprising the steps of: providing a plurality of look-up tables, the plurality of look-up tables representing a plurality of contrast settings of the LCD device; and selecting a single look-up table from the plurality of look-up tables in response to the contrast control setting selected by the user from the plurality of contrast settings through the contrast control device to affect a transfer function of the LCD device, the single look-up table containing all shade of gray available on the gray scale with each contrast setting.
Claim 3
Dependent Claim
14 words
The method of claim 1 , wherein the LCD device is an active-matrix LCD.
Claim 4
Dependent Claim
14 words
The method of claim 1 , wherein the LCD device is a passive-matrix LCD.
Claim 5
Dependent Claim
28 words
The method of claim 1 , further comprising the step of varying the drive voltages so that all shades of gray are available with a selected contrast setting.
Claim 6
Dependent Claim
29 words
The method of claim 1 , wherein the step of translating contrast control into a pre-defined transfer function comprises providing a contrast control input into the drive voltage generator.
Claim 7
Dependent Claim
13 words
The method of claim 5 , wherein the contrast control comprises digital signals.
Claim 8
Dependent Claim
13 words
The method of claim 5 , wherein the contrast control comprises analog signals.
Claim 9
Dependent Claim
17 words
The method of claim 7 , wherein the analog signals are a function of the drive voltages.
Claim 10
Dependent Claim
13 words
The method of claim 5 , wherein the contrast control comprises modulated signals.
Claim 11
Dependent Claim
14 words
The method of claim 9 , wherein the modulated signals are pulse-width modulated signals.
Claim 12
Dependent Claim
14 words
The method of claim 9 , wherein the modulated signals are amplitude modulated signals.
Claim 13
Dependent Claim
27 words
The method of claim 1 , wherein the contrast control is represented by drive voltages as a function of the shades of gray of the gray scale.
Claim 14
Dependent Claim
19 words
The method of claim 1 further comprising a plurality of viewing angle controls with respect to the LCD device.
Claim 15
Dependent Claim
14 words
The method of claim 1 , wherein the plurality of look-up tables are pre-determined.
Claim 16
Dependent Claim
12 words
The method of claim 1 , wherein the transfer function is non-linear.
Claim 17
Dependent Claim
48 words
The method of claim 15 , wherein the transfer function is defined by transmission T as a function of drive voltages V, and wherein the transfer function comprises a plurality of dynamic sets of drive voltages V and is not fixed to a single distribution of gray scale.
Claim 18
Independent Claim
210 words
An apparatus for controlling contrast in a liquid crystal display (LCD) device in which a gray scale comprising minimum light out to maximum light out is used with variable video signal input ranges, with each video signal input range comprising a fraction of a total range of zero to full amplitude to be displayed by the LCD device, the gray scale having a finite number of shades of gray, the LCD device having a contrast control for input by a user, the LCD device communicating with a drive voltage generator that supplies drive voltages V to the LCD device corresponding to the video signal input and a user defined contrast control setting, the LCD device comprising: a memory device containing a plurality of look-up tables, the plurality of look-up tables representing a plurality of contrast settings of the LCD device; and means for accessing the memory device to search through the plurality of look-up tables and for selecting a single look-up table from the plurality of look-up tables in response to the contrast setting selected by the user through the contrast control device to affect a transfer function of the LCD device, the single look-up table containing all shades of gray available on the gray scale with each contrast setting.
Claim 19
Independent Claim
210 words
An apparatus for controlling contrast in a liquid crystal display (LCD) device in which a gray scale comprising minimum light out to maximum light out is used with variable video signal input ranges, with each video signal input range comprising a fraction of a total range of zero to full amplitude to be displayed by the LCD device, the gray scale having a finite number of shades of gray, the LCD device having a contrast control for input by a user, the LCD device communicating with a drive voltage generator that supplies drive voltages V to the LCD device corresponding to the video signal input and a user defined contrast control setting, the LCD device comprising: a memory device containing a plurality of look-up tables, the plurality of look-up tables representing a plurality of contrast settings of the LCD device; and means for accessing the memory device to search through the plurality of look-up tables and for selecting a single look-up table from the plurality of look-up tables in response to the contrast setting selected by the user through the contrast control device to affect a transfer function of the LCD device, the single look-up table containing all shades of gray available on the gray scale with each contrast setting.
Claim 20
Dependent Claim
14 words
The apparatus of claim 17 , wherein the LCD device is an active-matrix LCD.
Claim 21
Dependent Claim
14 words
The apparatus of claim 18 , wherein the contrast control input comprises digital signals.
Claim 22
Dependent Claim
14 words
The apparatus of claim 17 , wherein the LCD device is a passive-matrix LCD.
Claim 23
Dependent Claim
24 words
The apparatus of claim 17 , wherein the drive voltages vary so that all shades of gray are available with a selected contrast setting.
Claim 24
Dependent Claim
29 words
The apparatus of claim 17 , wherein said apparatus for translating a contrast setting into a pre-defined transfer function comprises a contrast control input into the drive voltage generator.
Claim 25
Dependent Claim
14 words
The apparatus of claim 22 , wherein the contrast control input comprises analog signals.
Claim 26
Dependent Claim
17 words
The apparatus of claim 23 , wherein the analog signals are a function of the drive voltages.
Claim 27
Dependent Claim
14 words
The apparatus of claim 22 , wherein the contrast control input comprises modulated signals.
Claim 28
Dependent Claim
14 words
The apparatus of claim 25 , wherein the modulated signals are pulse-width modulated signals.
Claim 29
Dependent Claim
14 words
The apparatus of claim 25 , wherein the modulated signals are amplitude modulated signals.
Claim 30
Dependent Claim
27 words
The apparatus of claim 17 , wherein the contrast settings are represented by drive voltages as a function of the shades of gray of the gray scale.
Claim 31
Dependent Claim
19 words
The apparatus of claim 17 further comprising a plurality of viewing angle controls with respect to the LCD device.
Claim 32
Dependent Claim
17 words
The apparatus of claim 17 , wherein the plurality of look-up tables has contents that are pre-determined.
Claim 33
Dependent Claim
12 words
The apparatus of claim 17 , wherein the transfer function is non-linear.
Claim 34
Dependent Claim
48 words
The apparatus of claim 31 , wherein the transfer function is defined by transmission T as a function of drive voltages V, and wherein the transfer function comprises a plurality of dynamic sets of drive voltages V and is not fixed to a single distribution of gray scale.
Claim 35
Independent Claim
217 words
A method for controlling contrast in a liquid crystal display (“LCD”) device in which a gray scale comprising minimum light out to maximum light out is used with variable video signal input ranges, with each video signal input range comprising a fraction of a total range of zero to full amplitude to be displayed by the LCD device, the gray scale having a finite number of shades of gray, the LCD device having a contrast control for input by a user, the LCD device communicating with a drive voltage generator that supplies drive voltages V to the LCD device corresponding to the video signal input and user defined contrast control setting, the method comprising the steps of: providing a plurality of look-up tables, the plurality of look-up tables representing a plurality of contrast settings of the LCD device; and selecting a single look-up table from the plurality of look-up tables in response to the contrast setting selected by the user from the plurality of contrast settings through the contrast control device to affect a transfer function of the LCD device, the single look-up table containing all shades of gray available on the gray scale with each contrast setting, wherein the transfer function is non-linear and is defined by transmission T as a function of drive voltages V.
Claim 36
Independent Claim
217 words
A method for controlling contrast in a liquid crystal display (“LCD”) device in which a gray scale comprising minimum light out to maximum light out is used with variable video signal input ranges, with each video signal input range comprising a fraction of a total range of zero to full amplitude to be displayed by the LCD device, the gray scale having a finite number of shades of gray, the LCD device having a contrast control for input by a user, the LCD device communicating with a drive voltage generator that supplies drive voltages V to the LCD device corresponding to the video signal input and user defined contrast control setting, the method comprising the steps of: providing a plurality of look-up tables, the plurality of look-up tables representing a plurality of contrast settings of the LCD device; and selecting a single look-up table from the plurality of look-up tables in response to the contrast setting selected by the user from the plurality of contrast settings through the contrast control device to affect a transfer function of the LCD device, the single look-up table containing all shades of gray available on the gray scale with each contrast setting, wherein the transfer function is non-linear and is defined by transmission T as a function of drive voltages V.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2005-07-01 | 2005-12-31 | 2006-07-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-07-01 | 2009-12-31 | 2010-07-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-07-01 | 2013-12-31 | 2014-07-02 | $7700.00 | Window Closed / Lapsed |