EP0186036A2
Expired / Lapsed
EP
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Liquid crystal display device
Assignee: Philips Components Kobe KK
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Filing: 1985-12-10
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Granted: —
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Expires: 2005-12-10
Abstract
Abstract An active matrix liquid crystal display device is disclosed, which has a plurality of display electrodes (15) arranged in a matrix array and selectable through control of thin film transistors (16) for application of voltage between selected display electrodes (15) and a common electrode to obtain image display. Each thin film transistor (16) has a semiconductor layer (21) and a gate insulating film (22) both formed to have the same pattern. Each thin film transistor (16) has a gate electrode (23) formed on the gate insulating film (22) with the edges of the gate electrode (23) inwardly spaced apart from the corresponding edges of the gate insulating film (22). The semiconductor layer (21) and gate insulating film (22) preferably have extensions extending under a corresponding gate bus.
Inventors
- 👤 Shigeo Aoki
- 👤 Junichi Tamamura
- 👤 Yasuhiro Ukai
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 13:18
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/60; H10D30/67; H10D30/6729; H10D30/673; H10D30/6731; G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/136; G02F1/1362; G02F1/1368; H10D30/6704; H10D30/6723; H10D30/674; H10D30/6741; H10D30/6743; H10D30/6746
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
202 words
A liquid crystal display device characterized by: a liquid crystal cell including first and second transparent substrates (11,12) spaced apart a small distance and facing each other and a liquid crystal (14) sealed between said first and second transparent substrates (11,12); a common electrode (17) constituted by a transparent conductive film formed on the inner surface of said first transparent substrate (12); a plurality of display electrodes (15) constituted by a transparent conductive film formed on the inner surface of said second transparent substrate (11); and a plurality of thin film transistors (16) each having a drain connected to each of said display electrodes (15); each of said thin film transistors (16) including: a drain electrode (19a) constituted by a portion of said display electrode; a source electrode (15a) provided in the vicinity of said drain electrode (19a); a semiconductor layer (21) provided between and in contact with said drain and source electrodes (15a,19a); _a gate insulating film (22) having the same pattern as and perfectly overlying said semiconductor layer (21); and a gate electrode (23) formed on said gate insulating film (22), an edge of said gate electrode being spaced apart inwardly from the corresponding edge of said gate insulating film.
Claim 2
Dependent Claim
202 words
A liquid crystal display device characterized by: a liquid crystal cell including first and second transparent substrates (11,12) spaced apart a small distance and facing each other and a liquid crystal (14) sealed between said first and second transparent substrates (11,12); a common electrode (17) constituted by a transparent conductive film formed on the inner surface of said first transparent substrate (12); a plurality of display electrodes (15) constituted by a transparent conductive film formed on the inner surface of said second transparent substrate (11); and a plurality of thin film transistors (16) each having a drain connected to each of said display electrodes (15); each of said thin film transistors (16) including: a drain electrode (19a) constituted by a portion of said display electrode; a source electrode (15a) provided in the vicinity of said drain electrode (19a); a semiconductor layer (21) provided between and in contact with said drain and source electrodes (15a,19a); _a gate insulating film (22) having the same pattern as and perfectly overlying said semiconductor layer (21); and a gate electrode (23) formed on said gate insulating film (22), an edge of said gate electrode being spaced apart inwardly from the corresponding edge of said gate insulating film.
Claim 3
Dependent Claim
36 words
A liquid crystal display device according to claim 1, wherein said source electrodes (15a) and gate electrodes (23) of said plurality of thin film transistors are connected to source buses (19) and gate buses (18), respectively.
Claim 4
Dependent Claim
39 words
A liquid crystal display device according to claim 2, wherein auxiliary conductive layers (32) are formed on said source buses from the same material as said gate buses and spaced apart from said gate electrodes and said gate buses.
Claim 5
Dependent Claim
47 words
A liquid crystal display device according to claim 2 or 3, wherein said source buses (19) have terminals each constituted by a lamination of a first layer of the same material as said source buses and a second layer of the same material as said gate buses.
Claim 6
Dependent Claim
84 words
A liquid crystal display device according to claim 2, 3 or 4 comprising extensions of said semiconductor layer (21) and gate insulating film (22) provided underneath said gate buses (18); light-blocking layers (25) each formed on said second transparent substrate and facing each of said thin film transistors (16) above thereof; and extra width portions (25a) each formed as an extension of each of said light-blocking layers and substantially occupying an area of intersection between said gate bus (18) and said source bus (19).
Claim 7
Dependent Claim
133 words
A liquid crystal display device according to any one of claims 2 to 4 comprising: extensions of said semiconductor layer (21) and gate insulating film (22) provided underneath said gate buses (18); wherein the ratio L/W 3 of the distance L from one end of each said extension on the side of each gate bus terminal of said gate bus to the nearest thin film transistor connected to said gate bus to the width w3 of said gate bus is selected such that the current that flows from said nearest thin film transistor to the corresponding display electrode is higher by an order of magnitude or more than the current flowing from a parasitic transistor to said nearest thin film transistor on the side of said gate bus terminal to said display electrode.
Claim 8
Dependent Claim
18 words
A liquid crystal display device according to claim 6, wherein said ratio L/W 3 is 4.5 or above.
Claim 9
Dependent Claim
63 words
A liquid crystal display device according to any one of claims 1 to 4 comprising: light-blocking layers (25) each formed on said second transparent substrate and below said semiconductor layer of each said thin film transistor (16), said light-blocking layers being constituted by an amorphous silicon compound semiconductor having a narrower energy band gap and no less resistivity than those of amorphous silicon.
Claim 10
Dependent Claim
33 words
A liquid crystal display device according to claim 8, wherein the source and gate electrodes (15a,23) of each of said thin film transistors (16) are connected to said source and gate buses, respectively.
Claim 11
Dependent Claim
31 words
A liquid crystal display device according to any one of claims 1 to 4 or 9 wherein said semiconductor layer and gate insulating film have extensions provided underneath said gate buses.
Claim 12
Dependent Claim
66 words
A liquid crystal display device according to any one of claims 1 to 4, 6 or 10 which further comprises light-blocking layers (25) each formed on said second transparent substrate and below each of said thin film transistors (16), each said light-blocking layer having an extra width portion formed as an extension thereof to occupy an area of intersection between said gate bus and source bus.
Claim 13
Dependent Claim
40 words
A liquid crystal display device according to claim 11, wherein each said light-blocking layer with said extra width portion is constituted by a metal layer and an insulating layer is formed between said light-blocking layer and the corresponding semiconductor layer.
Claim 14
Dependent Claim
39 words
A liquid crystal display device according to claim 11, wherein said light-blocking layers with said extra width portions have substantially the same resistivity as the resistivity of said semiconductor layers and are each continuous to the corresponding semiconductor layer.
Claim 15
Dependent Claim
56 words
A liquid crystal display device according to claim 13, wherein said semiconductor layers are made of amorphous silicon and said light-blocking layers with said extra width portions are made of a compound semiconductor such as amorphous silicon germanium and amorphous silicon tin with an energy band gap less than the energy band gap of amorphous silicon.
Claim 16
Dependent Claim
78 words
15, A liquid crystal display device accordinq to any one of claims 1,2,5,6,9 and 10, wherein auxiliary conductive layers are formed on each said source bus such that they are spaced apart from said gate bus and each said gate electrode and each of said source buses has a terminal constituted by a lamination of a layer of the same material as said source bus and a metal layer of the same material - as said gate bus.
Claim 17
Dependent Claim
112 words
A liquid crystal display device according to claim 10 , wherein the ratio L/W 3 of the distance L from one end of each said extension on the side of each gate terminal of said gate bus to the nearest thin film transistor connected to said gate bus to the width W 3 of said gate bus is selected such that the current that flows from said nearest thin film transistor to the corresponding display electrode is higher by the order of one digit place or above than the current flowing a parasitic transistor to said nearest thin film transistor on the side of said gate bus terminal to said display electrode.
Claim 18
Dependent Claim
44 words
A liquid crystal display device according to claim 1, wherein said source and drain electrodes are contiguous to said light-blocking layer on the side of said semiconductor layer and said light-blocking layer, semiconductor layer, gate insulating film and gate electrode have the same pattern.
References Cited (Backward Citations)
No citation records indexed.
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