US6300927B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Display device
Assignee: Semiconductor Energy Laboratory Co Ltd
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Filing: 1997-09-17
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Granted: 2001-10-09
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Expires: 2017-09-17
Abstract
Abstract There is disclosed an active matrix liquid crystal display that receives input signals having small amplitudes and needs no externally attached level-shifting circuit. The active matrix liquid crystal display has a level-shifting circuit for amplifying various input signals, such as control signals, a clock signal, and a start pulse signal, and supplying the amplified signals to peripheral driver circuits. These peripheral driver circuits drive an active matrix circuit. The level-shifting circuit is made of a differential amplifier consisting of polysilicon TFTs. This amplifier is an analog amplifier. This level-shifting circuit is fabricated on the same substrate as the active matrix circuit and the peripheral driver circuits. If the amplitudes of the input signals are small, level-shifting operations can be performed well. Since any externally attached level-shifting circuit is dispensed with, the cost can be curtailed.
Inventors
- 👤 Yasushi Kubota
- 👤 Kenichi Katoh
- 👤 Jun Koyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:35
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/36; G09G3/3611; G09G3/3648; G09G3/3685; G09G3/3688; G09G3/3696; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1345; G02F1/13454; G09G2300/00; G09G2300/04; G09G2300/0404; G09G2300/0408; G09G2310/00; G09G2310/02; G09G2310/0264; G09G2310/0289; G09G2320/00; G09G2320/02; G09G2320/0252
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
122 words
A display device comprising: as active matrix circuit comprising thin-film transistors (TFTs) as switching devices and formed over an insulating substrate; a signal line driver circuit and a scanning line driver circuit for driving said active matrix circuit, said signal line driver circuit and said scanning line driver circuit being formed over said insulating substrate; and at least one differential amplifier formed over said insulating substrate and comprising TFTs, said differential amplifier having a pair of input terminals for a non-inverted input signal an inverted signal of said non-inverted input signal to amplify said non-inverted and inverted input signals, wherein the signal amplified by said differential amplifier is sent to said signal line driver circuit or to said scanning line driver circuit.
Claim 2
Dependent Claim
122 words
A display device comprising: as active matrix circuit comprising thin-film transistors (TFTs) as switching devices and formed over an insulating substrate; a signal line driver circuit and a scanning line driver circuit for driving said active matrix circuit, said signal line driver circuit and said scanning line driver circuit being formed over said insulating substrate; and at least one differential amplifier formed over said insulating substrate and comprising TFTs, said differential amplifier having a pair of input terminals for a non-inverted input signal an inverted signal of said non-inverted input signal to amplify said non-inverted and inverted input signals, wherein the signal amplified by said differential amplifier is sent to said signal line driver circuit or to said scanning line driver circuit.
Claim 3
Dependent Claim
17 words
A device according to claim 1 , wherein said input signals have amplitudes less than 5 V.
Claim 4
Dependent Claim
33 words
A device according to claim 1 , wherein said differential amplifier comprises a differential circuit comprising TFTs whose sources are connected together, and wherein a constant-current source is connected with said differential circuit.
Claim 5
Dependent Claim
52 words
A device according to claim 1 , wherein (A) said differential amplifier is an analog amplifier comprising a differential circuit which comprises TFTs whose sources are connected together; (B) a constant-current source is connected with said differential circuit; and (C) a source-grounded differential amplifier amplifies an output signal from said differential amplifier.
Claim 6
Dependent Claim
30 words
A device according to claim 1 , wherein said differential amplifier comprises low-temperature polysilicon TFTs fabricated by a low-temperature process having a maximum process temperature of 650° C. or less.
Claim 7
Dependent Claim
17 words
A device according to claim 1 , wherein said device is an active matrix liquid crystal device.
Claim 8
Dependent Claim
41 words
A display device according to claim 1 wherein said non-inverted input signals are at least one of a control signal, a clock signal and a start pulse signal and said inverted input signals are inverted signals of said non-inverted input signals.
Claim 9
Dependent Claim
17 words
A display device according to claim 1 wherein said display device is a liquid crystal display device.
Claim 10
Dependent Claim
146 words
A display device comprising: an active matrix circuit comprising a plurality of first thin film transistors formed over a substrate; a signal line driver circuit and a scanning line driver circuit for driving said active matrix circuit, both of said signal line driver circuit and said scanning line driver circuit comprising second polysilicon thin film transistors formed over said substrate; a single crystal semiconductor integrated circuit for generating signals for driving said signal line driver circuit and said scanning line driver circuit; and an analog amplifying circuit for amplifying the signals from said integrated circuit and supplying the amplified signals to at least one of the signal line driver circuit and the scanning line driver circuit, wherein said signals are at least one of control signals, clock signals, and start pulse signals, wherein said amplifying circuit comprises third polysilicon thin film transistors formed over said substrate.
Claim 11
Dependent Claim
146 words
A display device comprising: an active matrix circuit comprising a plurality of first thin film transistors formed over a substrate; a signal line driver circuit and a scanning line driver circuit for driving said active matrix circuit, both of said signal line driver circuit and said scanning line driver circuit comprising second polysilicon thin film transistors formed over said substrate; a single crystal semiconductor integrated circuit for generating signals for driving said signal line driver circuit and said scanning line driver circuit; and an analog amplifying circuit for amplifying the signals from said integrated circuit and supplying the amplified signals to at least one of the signal line driver circuit and the scanning line driver circuit, wherein said signals are at least one of control signals, clock signals, and start pulse signals, wherein said amplifying circuit comprises third polysilicon thin film transistors formed over said substrate.
Claim 12
Dependent Claim
20 words
A device according to claim 9 wherein said second and third polysilicon thin film transistors have substantially a same structure.
Claim 13
Dependent Claim
15 words
A device according to claim 9 wherein said analog amplifying circuit comprises a differential amplifier.
Claim 14
Dependent Claim
26 words
A device according to claim 7 wherein the signals from said integrated circuit and inverted signals of said signals are input to said analog amplifying circuit.
Claim 15
Dependent Claim
16 words
A display device according to claim 12 wherein said signals are at least a control signal.
Claim 16
Dependent Claim
16 words
A display device according to claim 12 wherein said signals are at least a clock signal.
Claim 17
Dependent Claim
17 words
A display device according to claim 12 wherein said signals are at least a start pulse signal.
Claim 18
Dependent Claim
17 words
A display device according to claim 9 wherein said display device is a liquid crystal display device.
Claim 19
Dependent Claim
167 words
A display device comprising: an active matrix circuit comprising a plurality of first thin film transistors formed over a substrate; a signal line driver circuit and a scanning line driver circuit for driving said active matrix circuit, both of said signal line driver circuit and said scanning line driver circuit comprising second thin film transistors formed over said substrate; at least one differential amplifier operationally connected to one of said signal line driver circuit and said scanning line driver circuit, said amplifier comprising at least one differential circuit and at least one current mirror circuit, wherein each of said differential circuit and said current mirror circuit comprises third thin film transistors formed over said substrate, wherein said differential amplifier has a pair of input terminals for an input signal and an inverted signal of said input signal, and said input signals are amplified by said differential amplifier, and the amplified signal is sent to one of said signal line driver circuit and said scanning line driver circuit.
Claim 20
Dependent Claim
167 words
A display device comprising: an active matrix circuit comprising a plurality of first thin film transistors formed over a substrate; a signal line driver circuit and a scanning line driver circuit for driving said active matrix circuit, both of said signal line driver circuit and said scanning line driver circuit comprising second thin film transistors formed over said substrate; at least one differential amplifier operationally connected to one of said signal line driver circuit and said scanning line driver circuit, said amplifier comprising at least one differential circuit and at least one current mirror circuit, wherein each of said differential circuit and said current mirror circuit comprises third thin film transistors formed over said substrate, wherein said differential amplifier has a pair of input terminals for an input signal and an inverted signal of said input signal, and said input signals are amplified by said differential amplifier, and the amplified signal is sent to one of said signal line driver circuit and said scanning line driver circuit.
Claim 21
Dependent Claim
21 words
A device according to claim 17 wherein each of said first, second and third thin film transistors has a polycrystal channel.
Claim 22
Dependent Claim
27 words
A display device according to claim 17 wherein at least a clock signal and an inverted signal of said clock signal are input to said differential amplifier.
Claim 23
Dependent Claim
27 words
A display device according to claim 17 wherein at least a control signal and an inverted signal of said control signal are input to said differential amplifier.
Claim 24
Dependent Claim
29 words
A display device according to claim 17 wherein at least a start pulse signal and an inverted signal of said start pulse signal are input to said differential amplifier.
Claim 25
Dependent Claim
17 words
A display device according to claim 17 wherein said display device is a liquid crystal display device.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-10-08 | 2005-04-09 | 2005-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-10-08 | 2009-04-09 | 2009-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-10-08 | 2013-04-09 | 2013-10-09 | $7700.00 | Window Closed / Lapsed |