Patent EP0504816A1 successfully refreshed from Google Patents.
EP0504816A1
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EP
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A method to obtain grey scales and higher frame speed in liquid crystal displays, having steep slope of the electrooptical characteristic
Assignee: Individual
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Filing: 1992-03-17
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Granted: —
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Expires: 2012-03-17
Abstract
Abstract Liquid crystal displays like supertwisted type, having a very steep slope of the electrooptical curve, or even bistability, are distinguished by high contrast and allow also to realize high numbers of addressable rows, means they offer higher information content. Unfortunately, no grey scales of acceptable quality can be obtained. According to the present invention, the data voltages (a,b,c) of the image, are superposed by a high frequency voltage (Hf) of triangle form and together are applied to the electrodes of the liquid crystal display. This method allow to display images with high quality grey scales. To adopt the display for moving pictures, a new method of divisional addressing was found out. The new method allow to double the frame speed, or to double the number of the addressable rows for high definition displays.
Inventors
- 👤 Michael Stalow
- 👤 Ilana Hecht
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 21:46
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/2007; G09G3/2011; G09G3/34; G09G3/36; G09G3/3611; H; H04; H04N; H04N3/00; H04N3/10; H04N3/12; H04N3/127; G09G2310/00; G09G2310/06
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
50 words
A matrix liquid crystal display having a steep slope of the electrooptical characteristic, comprising an electronic element for superposing an uninterrupted high frequency voltage of a triangular form and constant amplitude on top of the data voltages of any image, whereby an image with analog type grey scales is displayed.
Claim 2
Dependent Claim
43 words
A matrix liquid crystal display as in claim 1, wherein the liquid crystal material having a steep slope is of the type recommended for supertwisted liquid crystal displays, and the aligned twist angle is in the range from 90 degree to 270 degree.
Claim 3
Dependent Claim
44 words
A matrix liquid crystal display as in claim 1, comprising a liquid crystal material of the type recommended for twisted nematic liquid crystal displays, wherein every pixel of the said matrix is driven by diode means, causing a steep slope of the electrooptical characteristic.
Claim 4
Dependent Claim
26 words
A matrix liquid crystal display as in claim 1, wherein the liquid crystal material comprises a component of ferroelectric liquid crystal material, causing a steep slope.
Claim 5
Dependent Claim
65 words
A matrix liquid crystal display, having rows divided in several almost equal groups, where the rows of each group are located with intermissions, in which are located the rows of the subsequent groups in a interlined manner between the rows of the former groups wherein all said groups are energized in a sequential manner, and all said rows are displayed during every image frame time.
Claim 6
Dependent Claim
118 words
A matrix liquid crystal display as in claim 5, where said rows are divided in a first and second group, each one of said groups, comprises a half of the whole number of rows and located with intermissions, where said rows of said second group are located in a interlined manner between the rows of said first group, wherein a first group comprising all rows hawing uneven numbers, are energized sequential and displayed in the columns of the uneven numbers during one image frame time, and where the second group comprising all rows having even numbers is displayed in the columns of the even numbers, and are energized sequential and simultaneously with said rows of said first group.
Claim 7
Dependent Claim
76 words
A matrix liquid crystal display as in claim 6, wherein during one image frame time, said rows of uneven numbers are displayed in said columns of uneven numbers, and said rows of even numbers are displayed in said columns of even numbers, while during the next image frame time, said rows of uneven numbers are displayed in said columns of even numbers and said rows of even numbers are displayed in said columns of uneven numbers.
Claim 8
Dependent Claim
45 words
A matrix liquid crystal display as in claim 7, wherein said rows of said second group is energized in a interlined manner between said rows of said first group, but with a small delay, equal to a half time interval between energizing of two rows.
Claim 9
Dependent Claim
47 words
A matrix liquid crystal display as in claim 1, comprising a layer of a " R G B" color filter applied to any surface of said matrix liquid crystal display whereby a multicolor or a full color display with an analog type of grey scales is obtained
Claim 10
Dependent Claim
42 words
A matrix liquid crystal display as in claim 5, comprising a layer of a "R G B" color filter applied to any surface of said matrix liquid crystal display, whereby a high speed high resolution multicolor or full color display is obtained.
Claim 11
Dependent Claim
59 words
A matrix liquid crystal display as in claim 1, assembled as a multilayer liquid crystal device, comprising at least two liquid crystal displays assembled in series together with neutral and color polarizers, where the eliminative or subtractive color system are used, whereby multicolor or full color images with analog type grey scales for direct view or projection is obtained.
Claim 12
Dependent Claim
59 words
A matrix liquid crystal display as in claim 5, assembled as a multilayer liquid crystal device, comprising at least two liquid crystal displays, assembled in series together with neutral and color polarizers, wherein the eliminative or subtractive color system are used, whereby a multicolor or full color high speed high resolution display for direct view or projection is obtained.
Claim 13
Dependent Claim
71 words
A matrix liquid crystal display as in claim 1, assembled as a multibeam projection device, comprising three liquid crystal displays, wherein each of said liquid crystal displays is projected separately and independently through a different color filter selected from the three primary colors: red, green and blue, toward a common screen, whereby a multicolor or a full color three beam projection system with an analog type of gray scales is obtained.
Claim 14
Dependent Claim
70 words
A matrix liquid crystal display as in claim 5, assembled as a multibeam projection device, comprising three said liquid crystal displays, wherein each of said liquid crystal displays is projected separately and independently through a different color filter selected from the three primary colors: red, green and blue, toward a common screen, whereby a multicolor or full color three beam projection system of high speed and high resolution is obtained.
Claim 15
Dependent Claim
17 words
A matrix liquid crystal display as in claim 1, wherein said electronic element is a operational amplifier.
References Cited (Backward Citations)
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