EP0402984A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Passive ferro-electric liquid crystal display device and method of manufacturing such a device
Assignee: Koninklijke Philips NV
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Filing: 1990-06-06
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Granted: —
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Expires: 2010-06-06
Abstract
Abstract A faint transmission/voltage curve (10) which is suitable for adjusting grey scales is obtained for the entire pixel by preferably uniformly distributing the angles between the smectic layers (6) and the supporting plates (2, 3) across sub-areas (8) of a pixel (7).
Inventors
- 👤 Antonius Gerardus Hendrikus Verhulst
- 👤 Wilbert Jozef Antoon Marie Hartmann
- 👤 Franciscus Johannes Stommels
- 👤 Ann Masda Mauritia Luyckx-Smolders
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 11:16
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/137; G02F1/139; G02F1/141; G02F1/133; G02F1/1333; G02F1/1337; G02F1/133753; G02F1/133371; G02F1/133761; G02F1/1339; G02F1/13392; G02F2203/00; G02F2203/30
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
59 words
A liquid crystal device comprising a ferro-electric liquid crystal medium between two supporting plates provided with electrodes, which device has an adjustable light transmissivity, characterized in that, viewed across the surface of the device, the angle of the smectic layers of the ferro-electric liquid crystal molecules exhibits a spread with respect to at least one of the supporting plates.
Claim 2
Dependent Claim
59 words
A liquid crystal device comprising a ferro-electric liquid crystal medium between two supporting plates provided with electrodes, which device has an adjustable light transmissivity, characterized in that, viewed across the surface of the device, the angle of the smectic layers of the ferro-electric liquid crystal molecules exhibits a spread with respect to at least one of the supporting plates.
Claim 3
Dependent Claim
104 words
A display device as claimed in Claim 1, comprising a ferro-electric liquid crystalline medium between two supporting plates, the first of which comprises a system of row electrodes and the second comprises a system of column electrodes which define pixels at the crossings of row and column electrodes, characterized in that the angle of the smectic layers of the ferro-electric liquid crystal molecules exhibits a spread with respect to at least one of the supporting plates at least at the area of a part, defining a pixel, of a row electrode or of a column electrode, as viewed across the part defining the pixel.
Claim 4
Dependent Claim
34 words
A display device as claimed in Claim 1 or 2, characterized in that the transmission/voltage characteristic, viewed across the surface of the device or across the pixel, exhibits a spread of the threshold voltage.
Claim 5
Dependent Claim
21 words
A display device as claimed in any one of Claim 2 or 3, characterized in that the spread is substantially uniform.
Claim 6
Dependent Claim
39 words
A display device as claimed in any one of Claims 2 to 4, characterized in that one of the electrodes or the row or column electrode has a spread in its surface roughness at the location of the pixel.
Claim 7
Independent Claim
29 words
A device as claimed in any one of the preceding Claims, characterized in that the width of the tranmission range in the transmission/voltage characteristic is at least 0.5 Volt.
Claim 8
Dependent Claim
24 words
A display device as claimed in any one of Claims 2 to 6, characterized in that it comprises at least 10 spacers per pixel.
Claim 9
Dependent Claim
18 words
A display device as claimed in Claim 7, characterized in that the spacer particles are distributed substantially uniformly.
Claim 10
Dependent Claim
30 words
A display device as claimed in any one of Claims 2 to 8, characterized in that a desired transmission state is reached from an extreme transmission state during line selection.
Claim 11
Independent Claim
36 words
A method of manufacturing a device as claimed in any one of Claims 1 to 9, characterized in that the device is subjected to at least one low-frequency electric field treatment at a low field strength.
Claim 12
Dependent Claim
36 words
A method as claimed in Claim 10, characterized in that the device is subjected to at least one low-frequency treatment at a high field strength after the low-frequency electric field treatment at a low field strength.
Claim 13
Dependent Claim
27 words
A method as claimed in Claim 10 or 11, characterized in that the device is subjected to a plurality of low-frequency treatments at a different field strength.
Claim 14
Dependent Claim
32 words
A method as claimed in Claim 10, 11 or 12, characterized in that the device is subjected in advance to an electric field treatment in a field having a higher field strength.
Claim 15
Dependent Claim
24 words
A method as claimed in Claim 10, 11, 12 or 13, characterized in that the electric field treatment is combined with a thermal treatment.
Claim 16
Independent Claim
43 words
A method of manufacturing a display device as claimed in any one of Claims 1 to 9, characterized in that the spread of the angle of the smectic layers with respect to the supporting plates is obtained by means of a thermal treatment.
Claim 17
Dependent Claim
28 words
A method as claimed in Claim 14 or 15, characterized in that the thermal treatment comprises the steps of local heating, local cooling or providing a temperature gradient.
Claim 18
Independent Claim
44 words
A method of manufacturing a display device as claimed in any one of Claims 1 to 9, characterized in that the spread of the angle of the smectic layers with respect to the supporting plates is obtained by a mechanical or a chemical treatment.
References Cited (Backward Citations)
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