EP0179914A1
Expired / Lapsed
EP
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Liquid crystal display element and a method of producing the same
Assignee: Philips Components Kobe KK
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Filing: 1985-04-08
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Granted: —
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Expires: 2005-04-08
Abstract
Abstract A liquid crystal display element in which a plurality of display electrodes (15) are selected by turning on or turning off thin-film transistors (16) to produce display, and relates to a method of producing the same. According to the invention, in particular, the channel length of thin-film transistor (16) is shortened so that the element operates at high speeds while exhibiting uniform characteristics. The display electrode (15) and a source electrode (19a) are formed in a clear substrate (11) on one side of the liquid crystal display element, a semiconductor layer (21) is formed therebetween, a gate insulating film (22) is formed on the semiconductor layer (21), and a gate electrode (23) is formed on the gate insulating film (22) between the display electrode (15) and the source electrode (19a). With the gate electrode (23) as a mask, ions are implanted into the semiconductor layer (21), and portions of the semiconductor layer (21) connected to the display electrode (15) and to the source electrode (19a) are used as ohmic layers (27), (28), respectively, thereby to obtain a channel in which the distance between the ohmic layers (27) and (28) is determined by the length of the gate electrode (23).
Inventors
- 👤 Shigeo Aoki
- 👤 Yasuhiro Ugai
- 👤 Katsumi Miyake
- 👤 Kotaro Okamoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 02:16
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/60; G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/136; G02F1/1362; G02F1/1368; G02F1/1333; G02F1/1335; G02F1/133509; G02F1/133512
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
243 words
A liquid crystal display device comprising first and second transparent substrates closely spaced apart and facing each other, a liquid crystal sealed between said transparent substrates, a plurality of display electrodes provided on the inner surface of said first transparent substrate, thin film transistors formed on said first transparent substrate and each having the drain connected to said display electrode, and a transparent common electrode formed on and substantially over the entire inner surface of said second transparent substrate, said thin film transistors being selectively controlled for switching to apply a voltage between selected display electrodes and said common electrode for display, said thin film transistors each including a semiconductor layer provided between the corresponding display electrode and the source electrode, said semiconductor layer partly overlying said display electrode and the drain electrode on the side thereof opposite said first transparent substrate, a gate insulating film formed on said semiconductor layer on the side thereof opposite said first transparent substrate, and a gate electrode formed on said gate insulating film, gaps being defined between the opposite ends of said gate electrode and said display electrode and the source electrode when viewed in the perpendicular direction to said first transparent substrate, portions of said semiconductor layer corresponding to said gaps and portions of said semiconductor layer overlying said display electrode and source electrode being rendered to be ohmic layers having a sufficiently high impurity concentration compared to the impurity concentration of said semiconductor layer.
Claim 2
Dependent Claim
243 words
A liquid crystal display device comprising first and second transparent substrates closely spaced apart and facing each other, a liquid crystal sealed between said transparent substrates, a plurality of display electrodes provided on the inner surface of said first transparent substrate, thin film transistors formed on said first transparent substrate and each having the drain connected to said display electrode, and a transparent common electrode formed on and substantially over the entire inner surface of said second transparent substrate, said thin film transistors being selectively controlled for switching to apply a voltage between selected display electrodes and said common electrode for display, said thin film transistors each including a semiconductor layer provided between the corresponding display electrode and the source electrode, said semiconductor layer partly overlying said display electrode and the drain electrode on the side thereof opposite said first transparent substrate, a gate insulating film formed on said semiconductor layer on the side thereof opposite said first transparent substrate, and a gate electrode formed on said gate insulating film, gaps being defined between the opposite ends of said gate electrode and said display electrode and the source electrode when viewed in the perpendicular direction to said first transparent substrate, portions of said semiconductor layer corresponding to said gaps and portions of said semiconductor layer overlying said display electrode and source electrode being rendered to be ohmic layers having a sufficiently high impurity concentration compared to the impurity concentration of said semiconductor layer.
Claim 3
Dependent Claim
31 words
The liquid crystal display device according to claim 1, wherein an opaque metal layer is formed between each said thin film transistor and said first transparent substrate via an insulating layer.
Claim 4
Dependent Claim
52 words
The liquid crystal display device according to claim 2, wherein source buses of the same'material as said opaque metal layers are formed on the side of said first transparent substrate more than said source electrodes are, said source buses being connected to said source buses through holes formed in said insulating layers.
Claim 5
Dependent Claim
59 words
The liquid crystal display device according to claim 3, wherein second source buses of the same material as said source electrodes are formed on the side of said insulating layer opposite said first transparent substrate, and said second source buses and said source buses of the same material as said opaque metal layers being connected together at source terminals.
Claim 6
Dependent Claim
36 words
The liquid crystal display device according to one of claims 1 to 4, wherein light-blocking layers of an opaque metal are formed on portions of said second transparent substrate corresponding to gaps between adjacent display electrodes.
Claim 7
Dependent Claim
26 words
The liquid crystal display device according to claim 5, wherein color filters are formed on said second transparent substrate such that they face said display electrodes.
Claim 8
Dependent Claim
24 words
The liquid crystal display device according to claim 6, wherein said light-blocking layers are formed between said common elecrode and said second transparent substrate.
Claim 9
Dependent Claim
27 words
The liquid crystal display device according to claim 7, wherein said light-blocking layers partly overlies said color filters on the side thereof opposite said second transparent substrate.
Claim 10
Dependent Claim
89 words
The liquid crystal display device according to claim 6, wherein said display electrodes are picture element electrodes arranged in a matrix array, said thin film transistors connected to the picture element electrodes in each column have their source electrodes connected to a common source bus, said thin film transistors connected to the picture element electrodes in each row of said matrix array have their gate electrodes connected to a common gate bus, and said color filters consist of a plurality of different color filters which are substantially uniformly distributed.
Claim 11
Dependent Claim
76 words
The liquid crystal display device according to one of claims 1 to 5, wherein said display electrodes are picture element electrodes arranged in a matrix array, said thin film transistors connected to the picture element electrodes in each column have their source electrodes connected to a common source bus, and 'said thin film transistors connected to the picture element electrodes in each row of said matrix array have their gate,electrodes connected to a common gate bus.
Claim 12
Independent Claim
225 words
A method of manufacturing a liquid crystal display device by the steps of forming a plurality of display electrodes and thin film transistors connected thereto on one surface of a first transparent substrate, forming a transparent common electrode on one surface of a second transparent substrate and sealing liquid crystal between said first and second transparent'substrate with said display electrodes and common electrode on the inner side, said display electrodes and thin film transistors being formed by: a step of forming a plurality of display electrodes and drain electrodes in the proximity thereof from a transparent metal on said one surface of said first transparent substrate, a step of forming semiconductor layers on said first transparent substrate such that each said semiconductor layer extends between the display electrode and the drain electrode in the proximity thereof, a step of forming a gate insulating film on said semiconductor layers, a step of forming gate electrodes on said gate insulating film such that each said gate electrode extends between each display electrode and corresponding source electrode, and a step of implanting ions into each said semiconductor layer with each said gate electrode used as a mask to thereby render portions of said semiconductor layer contiguous to said display electrode and source electrode into ohmic contact layers having length dimensions determined by the length of said gate electrode.
Claim 13
Independent Claim
225 words
A method of manufacturing a liquid crystal display device by the steps of forming a plurality of display electrodes and thin film transistors connected thereto on one surface of a first transparent substrate, forming a transparent common electrode on one surface of a second transparent substrate and sealing liquid crystal between said first and second transparent'substrate with said display electrodes and common electrode on the inner side, said display electrodes and thin film transistors being formed by: a step of forming a plurality of display electrodes and drain electrodes in the proximity thereof from a transparent metal on said one surface of said first transparent substrate, a step of forming semiconductor layers on said first transparent substrate such that each said semiconductor layer extends between the display electrode and the drain electrode in the proximity thereof, a step of forming a gate insulating film on said semiconductor layers, a step of forming gate electrodes on said gate insulating film such that each said gate electrode extends between each display electrode and corresponding source electrode, and a step of implanting ions into each said semiconductor layer with each said gate electrode used as a mask to thereby render portions of said semiconductor layer contiguous to said display electrode and source electrode into ohmic contact layers having length dimensions determined by the length of said gate electrode.
Claim 14
Dependent Claim
62 words
The method of manufacturing a liquid crystal display device according to claim 11, wherein a step of forming opaque metal layers on areas of. said first transparent substrate where said thin film transistors are to be formed and a step of forming an insulating film on said opaque metal layers are included before the formation of said display electrodes and source electrodes.
Claim 15
Dependent Claim
71 words
The method of manufactured a liquid crystal display device according to claim 13, wherein source buses of the same material as said opaque metal layers are formed together with said opaque metal layers on said first transparent substrate, holes are formed in portions of said insulating film where said source electrodes are to be formed, and then said source electrodes are formed such that they are connected to said source buses.
Claim 16
Dependent Claim
49 words
The method of manufacturing a liquid crystal display device according to claim 13, wherein second source buses connected to and of the same material as said source electrodes are formed together with said source electrodes, said second source buses and said source buses being connected together at source terminals.
Claim 17
Dependent Claim
36 words
The method of manufacturing a liquid crystal display device according to claim 11 or 12, wherein a step of laser annealing said ohmic contact layer portions with said gate electrode used as a mask is included.
References Cited (Backward Citations)
No citation records indexed.
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