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US5598284A
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Electro-optical device defined by relationship of data voltage, residual voltage, spontaneous polarization, and liquid crystal time constant and capacitance
Assignee: Semiconductor Energy Laboratory Co Ltd
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Filing: 1994-12-16
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Granted: 1997-01-28
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Expires: 2014-12-16
Abstract
Abstract A liquid crystal electro-optical device has electrodes, a pair of substrates at least one of which is transparent, thin-film transistors provided on one of the pair of substrates, and a ferroelectric or antiferroelectric liquid crystal material, or a ferroelectric or antiferroelectric liquid crystal material mixed with a polymer compound held between the pair of substrates. A particular relationship is established between spontaneous polarization of the liquid crystal material, a capacitance between pixel electrodes, a pulse voltage applied to gates of the transistors, a time constant of a pixel, a residual pixel voltage immediately before application of the next pulse, and other parameters.
Inventors
- 👤 Noriaki Kogushi
- 👤 Takeshi Nishi
- 👤 Masaaki Hiroki
- 👤 Toshiharu Yamaguchi
- 👤 Toshimitsu Konuma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 08:51
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/137; G02F1/139; G02F1/141; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/36; G09G3/3611; G09G3/3648; G09G3/3651; G02F1/133; G02F1/13306; G02F1/136; G02F1/1362; G02F1/1368; G09G3/2007; G09G3/2018; G09G3/3614
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
200 words
An electro-optical device comprising: a pair of substrates; a transistor provided on one of the pair of substrates; a pixel electrode provided on the one of the pair of substrates and connected with one of source and drain of the transistor; another electrode provided on the other of the pair of substrates; and an electro-optical modulating layer provided between the pair of substrates, the electro-optical modulating layer comprising a material selected from the group consisting of a ferroelectric liquid crystal, an antiferroelectric liquid crystal and a mixture thereof with a polymer, wherein a formula C.sub.LC {V-V.sub.rem -2V exp(-W/τ.sub.LC)}>2 P s S holds where P S is spontaneous polarization of the ferroelectric liquid crystal or the antiferroelectric liquid crystal, C LC is a capacitance between the pixel electrode and the another electrode, V is a magnitude of a pulse voltage applied to a the pixel electrode, W is a width of the pulse voltage τ LC is a time constant of a pixel comprising the pixel electrode, S is an area of the pixel electrode, and V rem is a residual voltage due to residual charge between the pixel electrode and the another electrode immediately before application of a next pulse.
Claim 2
Dependent Claim
200 words
An electro-optical device comprising: a pair of substrates; a transistor provided on one of the pair of substrates; a pixel electrode provided on the one of the pair of substrates and connected with one of source and drain of the transistor; another electrode provided on the other of the pair of substrates; and an electro-optical modulating layer provided between the pair of substrates, the electro-optical modulating layer comprising a material selected from the group consisting of a ferroelectric liquid crystal, an antiferroelectric liquid crystal and a mixture thereof with a polymer, wherein a formula C.sub.LC {V-V.sub.rem -2V exp(-W/τ.sub.LC)}>2 P s S holds where P S is spontaneous polarization of the ferroelectric liquid crystal or the antiferroelectric liquid crystal, C LC is a capacitance between the pixel electrode and the another electrode, V is a magnitude of a pulse voltage applied to a the pixel electrode, W is a width of the pulse voltage τ LC is a time constant of a pixel comprising the pixel electrode, S is an area of the pixel electrode, and V rem is a residual voltage due to residual charge between the pixel electrode and the another electrode immediately before application of a next pulse.
Claim 3
Dependent Claim
25 words
The device of claim 1 wherein the electro-optical modulating layer comprises the mixture, and the polymer has a columnar shape between the pair of substrates.
Claim 4
Dependent Claim
29 words
The device of claim 1 wherein the electro-optical modulating layer comprises the ferroelectric liquid crystal and the ferroelectric liquid crystal has a relative dielectric constant of 6 or more.
Claim 5
Dependent Claim
29 words
The device of claim 1 wherein the electro-optical modulating layer comprises the antiferroelectric liquid crystal and the antiferroelectric liquid crystal has a relative dielectric constant of 6 or more.
Claim 6
Dependent Claim
30 words
The device of claim 1 wherein the electro-optical modulating layer comprises the ferroelectric liquid crystal and the width W is shorter than a response time of the ferroelectric liquid crystal.
Claim 7
Dependent Claim
30 words
The device of claim 1 wherein the electro-optical modulating layer comprises the antiferroelectric liquid crystal and the width W is shorter than a response time of the antiferroelectric liquid crystal.
Claim 8
Dependent Claim
232 words
An electro-optical device comprising: a pair of substrates; a transistor provided on one of the pair of substrates; a pixel electrode provided on the one of the pair of substrates and connected with one of source and drain of the transistor; another electrode provided on the other of the pair of substrates; and an electro-optical modulating layer provided between the pair of substrates, the electro-optical modulating layer comprising a material selected from the group consisting of a ferroelectric liquid crystal, an antiferroelectric liquid crystal and a mixture thereof with a polymer, wherein a formula C.sub.LC {V-V.sub.rem -2V exp(-W/τ.sub.LC)}+C.sub.AD {V-V.sub.rem -2V exp(-W/τ)}≧2 P s S holds where P S is spontaneous polarization of the ferroelectric liquid crystal or the antiferroelectric liquid crystal, C LC is a capacitance between the pixel electrode and the another electrode, C AD is a capacitance of an auxiliary capacitor connected with the capacitance C LC , V is a magnitude of a pulse voltage applied to the pixel electrode, W is a, width of the pulse voltage, τ LC is a time constant of a pixel comprising the pixel electrode, τ is a time constant of an auxiliary circuit comprising the capacitance C AD , S is an area of the pixel electrode, and V rem is a residual voltage due to residual charge between pixel electrode and the another electrode immediately before application of a next pulse.
Claim 9
Dependent Claim
232 words
An electro-optical device comprising: a pair of substrates; a transistor provided on one of the pair of substrates; a pixel electrode provided on the one of the pair of substrates and connected with one of source and drain of the transistor; another electrode provided on the other of the pair of substrates; and an electro-optical modulating layer provided between the pair of substrates, the electro-optical modulating layer comprising a material selected from the group consisting of a ferroelectric liquid crystal, an antiferroelectric liquid crystal and a mixture thereof with a polymer, wherein a formula C.sub.LC {V-V.sub.rem -2V exp(-W/τ.sub.LC)}+C.sub.AD {V-V.sub.rem -2V exp(-W/τ)}≧2 P s S holds where P S is spontaneous polarization of the ferroelectric liquid crystal or the antiferroelectric liquid crystal, C LC is a capacitance between the pixel electrode and the another electrode, C AD is a capacitance of an auxiliary capacitor connected with the capacitance C LC , V is a magnitude of a pulse voltage applied to the pixel electrode, W is a, width of the pulse voltage, τ LC is a time constant of a pixel comprising the pixel electrode, τ is a time constant of an auxiliary circuit comprising the capacitance C AD , S is an area of the pixel electrode, and V rem is a residual voltage due to residual charge between pixel electrode and the another electrode immediately before application of a next pulse.
Claim 10
Dependent Claim
22 words
The device of claim 7 wherein the auxiliary circuit further comprises a resistance provided in parallel with the capacitance C AD .
Claim 11
Dependent Claim
29 words
The device of claim 7 wherein the electro-optical modulating layer comprises the ferroelectric liquid crystal and the ferroelectric liquid crystal has a relative dielectric constant of 4 or more.
Claim 12
Dependent Claim
29 words
The device of claim 7 wherein the electro-optical modulating layer comprises the antiferroelectric liquid crystal and the antiferroelectric liquid crystal has a relative dielectric constant of 4 or more.
Claim 13
Dependent Claim
30 words
The device of claim 7 wherein the electro-optical modulating layer comprises the ferroelectric liquid crystal and the width W is shorter than a response time of the ferroelectric liquid crystal.
Claim 14
Dependent Claim
30 words
The device of claim 7 wherein the electro-optical modulating layer comprises the antiferroelectric liquid crystal and the width W is shorter than a response time of the antiferroelectric liquid crystal.
Claim 15
Dependent Claim
25 words
The device of claim 7 wherein the electro-optical modulating layer comprises the mixture, and the polymer has a columnar shape between the pair of substrates.
Claim 16
Dependent Claim
199 words
An electro-optical device comprising: a pair of substrates; a transistor provided on one of the pair of substrates; a pixel electrode provided on the one of the pair of substrates and connected with one of source and drain of the transistor; another electrode provided on the other of the pair of substrates; and an electro-optical modulating layer provided between the pair of substrates, the electro-optical modulating layer comprising a material selected from the group consisting of a ferroelectric liquid crystal, an antiferroelectric liquid crystal and a mixture thereof with a polymer, wherein a formula C.sub.LC {V-V.sub.rem -3V exp(-W/τ.sub.LC)}≧2 P s S holds where P S is spontaneous polarization of the ferroelectric liquid crystal or the antiferroelectric liquid crystal, C LC is a capacitance between the pixel electrode and the another electrode, V is a magnitude of a pulse voltage applied to the pixel electrode, W is a width of the pulse voltage τ LC is a time constant of a pixel comprising the pixel electrode, S is an area of the pixel electrode, and V rem is a residual voltage due to residual charge between the pixel electrode and the another electrode immediately before application of a next pulse.
Claim 17
Dependent Claim
199 words
An electro-optical device comprising: a pair of substrates; a transistor provided on one of the pair of substrates; a pixel electrode provided on the one of the pair of substrates and connected with one of source and drain of the transistor; another electrode provided on the other of the pair of substrates; and an electro-optical modulating layer provided between the pair of substrates, the electro-optical modulating layer comprising a material selected from the group consisting of a ferroelectric liquid crystal, an antiferroelectric liquid crystal and a mixture thereof with a polymer, wherein a formula C.sub.LC {V-V.sub.rem -3V exp(-W/τ.sub.LC)}≧2 P s S holds where P S is spontaneous polarization of the ferroelectric liquid crystal or the antiferroelectric liquid crystal, C LC is a capacitance between the pixel electrode and the another electrode, V is a magnitude of a pulse voltage applied to the pixel electrode, W is a width of the pulse voltage τ LC is a time constant of a pixel comprising the pixel electrode, S is an area of the pixel electrode, and V rem is a residual voltage due to residual charge between the pixel electrode and the another electrode immediately before application of a next pulse.
Claim 18
Dependent Claim
29 words
The device of claim 14 wherein the electro-optical modulating layer comprises the ferroelectric liquid crystal and the ferroelectric liquid crystal has a relative dielectric constant of 6 or more.
Claim 19
Dependent Claim
29 words
The device of claim 14 wherein the electro-optical modulating layer comprises the antiferroelectric liquid crystal and the antiferroelectric liquid crystal has a relative dielectric constant of 6 or more.
Claim 20
Dependent Claim
30 words
The device of claim 14 wherein the electro-optical modulating layer comprises the ferroelectric liquid crystal and the width W is shorter than a response time of the ferroelectric liquid crystal.
Claim 21
Dependent Claim
30 words
The device of claim 14 wherein the electro-optical modulating layer comprises the antiferroelectric liquid crystal and the width W is shorter than a response time of the antiferroelectric liquid crystal.
Claim 22
Dependent Claim
25 words
The device of claim 14 wherein the electro-optical modulating layer comprises the mixture, and the polymer has a columnar shape between the pair of substrates.
Claim 23
Dependent Claim
233 words
An electro-optical device comprising: a pair of substrates; a transistor provided on one of the pair of substrates; a pixel electrode provided on the one of the pair of substrates and connected with one of source and drain of the transistor; another electrode provided on the other of the pair of substrates; and an electro-optical modulating layer provided between the pair of substrates, the electro-optical modulating layer comprising a material selected from the group consisting of a ferroelectric liquid crystal, an antiferroelectric liquid crystal and a mixture thereof with a polymer, wherein a formula C.sub.LC {V-V.sub.rem -3V exp(-W/τ.sub.LC)}+C.sub.AD {V-V.sub.rem -3V exp(-W/τ)}≧2 P s S holds where P S is spontaneous polarization of the ferroelectric liquid crystal or the antiferroelectric liquid crystal, C LC is a capacitance between the pixel electrode and the another electrode, C AD is a capacitance of an auxiliary capacitor connected with the capacitance C LC , V is a magnitude of a pulse voltage applied to the pixel electrode, W is a width of the pulse voltage, τ LC is a time constant of a pixel comprising the pixel electrode, S is an area of the pixel electrode, τ is a time constant of an auxiliary circuit comprising the capacitance C AD , and V rem is a residual voltage due to residual charge between the pixel electrode and the another electrode immediately before application of a next pulse.
Claim 24
Dependent Claim
233 words
An electro-optical device comprising: a pair of substrates; a transistor provided on one of the pair of substrates; a pixel electrode provided on the one of the pair of substrates and connected with one of source and drain of the transistor; another electrode provided on the other of the pair of substrates; and an electro-optical modulating layer provided between the pair of substrates, the electro-optical modulating layer comprising a material selected from the group consisting of a ferroelectric liquid crystal, an antiferroelectric liquid crystal and a mixture thereof with a polymer, wherein a formula C.sub.LC {V-V.sub.rem -3V exp(-W/τ.sub.LC)}+C.sub.AD {V-V.sub.rem -3V exp(-W/τ)}≧2 P s S holds where P S is spontaneous polarization of the ferroelectric liquid crystal or the antiferroelectric liquid crystal, C LC is a capacitance between the pixel electrode and the another electrode, C AD is a capacitance of an auxiliary capacitor connected with the capacitance C LC , V is a magnitude of a pulse voltage applied to the pixel electrode, W is a width of the pulse voltage, τ LC is a time constant of a pixel comprising the pixel electrode, S is an area of the pixel electrode, τ is a time constant of an auxiliary circuit comprising the capacitance C AD , and V rem is a residual voltage due to residual charge between the pixel electrode and the another electrode immediately before application of a next pulse.
Claim 25
Dependent Claim
20 words
The device of claim 20 wherein the auxiliary circuit further comprises a resistance provided in parallel with the capacitance CAD.
Claim 26
Dependent Claim
29 words
The device of claim 20 wherein the electro-optical modulating layer comprises the ferroelectric liquid crystal and the ferroelectric liquid crystal has a relative dielectric constant of 4 or more.
Claim 27
Dependent Claim
29 words
The device of claim 20 wherein the electro-optical modulating layer comprises the antiferroelectric liquid crystal and the antiferroelectric liquid crystal has a relative dielectric constant of 4 or more.
Claim 28
Dependent Claim
30 words
The device of claim 20 wherein the electro-optical modulating layer comprises the ferroelectric liquid crystal and the width W is shorter than a response time of the ferroelectric liquid crystal.
Claim 29
Dependent Claim
30 words
The device of claim 20 wherein the electro-optical modulating layer comprises the antiferroelectric liquid crystal and the width W is shorter than a response time of the antiferroelectric liquid crystal.
Claim 30
Dependent Claim
25 words
The device of claim 20 wherein the electro-optical modulating layer comprises the mixture, and the polymer has a columnar shape between the pair of substrates.
References Cited (Backward Citations)
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