EP0313331A2
Expired / Lapsed
EP
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Real time method and apparatus for adjusting contrast ratio of liquid crystal displays
Assignee: Boeing North American Inc
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Filing: 1988-10-19
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Granted: —
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Expires: 2008-10-19
Abstract
Abstract A microprocessor manipulates the gray scale voltage levels in a liquid crystal display panel (100), in order to provide for enhanced image quality over temperature extremes by monitoring the actual transmittance through the liquid crystal display (100) over time and comparing the information with earlier information. The transmittance information is obtained by monitoring the output of a photo conductor (108) at a corner of the panel (100) in response to the light received through the panel (100) from a light emitting diode (106) while varying the voltage applied to the respective liquid crystal.
Inventors
- 👤 Lyle R. Strathman
- 👤 Craig E. Harwood
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 18:59
CPC Classifications
H; H04; H04N; H04N3/00; H04N3/10; H04N3/12; H04N3/127; G; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/36; G09G2320/00; G09G2320/02; G09G2320/029; G09G2320/04; G09G2320/041; G09G2360/00; G09G2360/14; G09G2360/145
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
55 words
A method for improving the image quality of liquid crystal displays which operate in environments having temperature variations comprising the steps of: a. determining the transmittance through a liquid crystal panel as a function of voltage; and b. adjusting predetermined gray scale voltage levels in response to the transmittance as a function of voltage determination.
Claim 2
Independent Claim
55 words
A method for improving the image quality of liquid crystal displays which operate in environments having temperature variations comprising the steps of: a. determining the transmittance through a liquid crystal panel as a function of voltage; and b. adjusting predetermined gray scale voltage levels in response to the transmittance as a function of voltage determination.
Claim 3
Independent Claim
83 words
An apparatus for improving the image quality of liquid crystal panels which oerate in environments having temperatues variations, comprising: a. means (106) for producing predetermined light level; b. means (108) for sensing the light transmitted through the liquid crystal panel (100); c. means (114) for manipulating the voltage across the liquid crystal panel; d. means for monitoring the light transmitted through the liquid crystal panel as a function of the voltage across the panel; and e. means for manipulating the gray scale levels.
Claim 4
Independent Claim
83 words
An apparatus for improving the image quality of liquid crystal panels which oerate in environments having temperatues variations, comprising: a. means (106) for producing predetermined light level; b. means (108) for sensing the light transmitted through the liquid crystal panel (100); c. means (114) for manipulating the voltage across the liquid crystal panel; d. means for monitoring the light transmitted through the liquid crystal panel as a function of the voltage across the panel; and e. means for manipulating the gray scale levels.
Claim 5
Dependent Claim
35 words
An apparatus according to Claim 2, characterised in that the means for producing a predetermined light level further comprises a light emitting diode (106) disposed on a first surface of the liquid crystal panel (100).
Claim 6
Dependent Claim
44 words
An apparatus according to Claim 3, characterised in that the means for sensing the light transmitted through the liquid crystal panel (100) further comprises a photo diode (108) disposed on the opposite side of the panel with respect to the light emitting diode (106).
Claim 7
Dependent Claim
50 words
An apparatus according to Claim 4, characterised in that the means for manipulating the voltage acroas the liquid crystal panel (100) further comprises: a. means (114) for generating a series of different voltages across the liquid crystal panel (100) for producing different transmittance levels through the liquid crystal panel (100).
Claim 8
Independent Claim
143 words
An apparatus for improving the image quality of liquid crystal displays which operate in environments with temperature variations comprising: a. liquid crystal with predetermined dimensional characteristics and having a first side and a second side; b. a light emitting diode (106) disposed on the first side of the liquid crystal for generating a predetermined light level to be transmitted through the liquid crystal display (100); c. a photo conductor (108) disposed on the second surface of the liquid crystal for generating a signal in response to the light incident thereon; d. means (114) for generating a series of different voltages across the liquid crystal for creating variable transmittance therethrough; e. means for comparing the photo conductor output for a plurality of the voltages across the display (100); and f. means for determining the relationship between the variable voltages and the photo conductor output.
Claim 9
Independent Claim
143 words
An apparatus for improving the image quality of liquid crystal displays which operate in environments with temperature variations comprising: a. liquid crystal with predetermined dimensional characteristics and having a first side and a second side; b. a light emitting diode (106) disposed on the first side of the liquid crystal for generating a predetermined light level to be transmitted through the liquid crystal display (100); c. a photo conductor (108) disposed on the second surface of the liquid crystal for generating a signal in response to the light incident thereon; d. means (114) for generating a series of different voltages across the liquid crystal for creating variable transmittance therethrough; e. means for comparing the photo conductor output for a plurality of the voltages across the display (100); and f. means for determining the relationship between the variable voltages and the photo conductor output.
References Cited (Backward Citations)
No citation records indexed.
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