Patent US4729640A successfully refreshed from Google Patents.
US4729640A
Expired / Lapsed
US
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Liquid crystal light modulation device
Assignee: Canon Inc
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Filing: 1985-10-01
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Granted: 1988-03-08
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Expires: 2005-10-01
Abstract
Abstract A liquid crystal light modulation device conprises a pair of substrates at least one of which is transparent, a diffraction grating formed between or on at least one of the substrates, a liquid crystal arranged between fine grooves of the diffraction grating, and control means for changing the orientation of the liquid crystal which has been oriented in a predetermined state by the grooves of the diffraction grating.
Inventors
- 👤 Hajime Sakata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:55
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/133371; G02F2201/00; G02F2201/30; G02F2201/305; G02F2203/00; G02F2203/22
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
217 words
A liquid crystal liquid modulation device comprising: a first substrate and a second substrate; said first substrate having a light-incident side for receiving incident light and a facing side facing said second substrate, said second substrate having a facing side facing said facing side of said first substrate, and said facing sides of said first and second substrates being parallel with each other and spaced a predetermined distance from each other; an optical element having plural portions, and liquid crystals, said portions of said optical element and said liquid crystals being alternately arranged between said first and second substrates, the heights of said portions of said optical element and said liquid crystals in a direction normal to said facing sides being substantially the same, and said liquid crystals being separated from one another by the intervening portions of said optical element; and control means for changing the refractive index of said liquid crystals, said control means causing said liquid crystals selectively to have at least two refractive indexes, one of said refractive indexes being substantially the same as that of said optical element and the other of said refractive indexes being different from that of said optical element so as to form a diffraction grating by said alternatively arranged liquid crystals and portions of said optical element.
Claim 2
Dependent Claim
217 words
A liquid crystal liquid modulation device comprising: a first substrate and a second substrate; said first substrate having a light-incident side for receiving incident light and a facing side facing said second substrate, said second substrate having a facing side facing said facing side of said first substrate, and said facing sides of said first and second substrates being parallel with each other and spaced a predetermined distance from each other; an optical element having plural portions, and liquid crystals, said portions of said optical element and said liquid crystals being alternately arranged between said first and second substrates, the heights of said portions of said optical element and said liquid crystals in a direction normal to said facing sides being substantially the same, and said liquid crystals being separated from one another by the intervening portions of said optical element; and control means for changing the refractive index of said liquid crystals, said control means causing said liquid crystals selectively to have at least two refractive indexes, one of said refractive indexes being substantially the same as that of said optical element and the other of said refractive indexes being different from that of said optical element so as to form a diffraction grating by said alternatively arranged liquid crystals and portions of said optical element.
Claim 3
Dependent Claim
19 words
A liquid crystal light modulation device according to claim 1 wherein said diffraction grating is a rectangular diffraction grating.
Claim 4
Dependent Claim
21 words
A liquid crystal light modulation device according to claim 1 wherein said diffraction grating is a triangular or brazed diffraction grating.
Claim 5
Dependent Claim
19 words
A liquid crystal light modulation device according to claim 1 wherein said diffraction grating is a sinusoidal diffraction grating.
Claim 6
Dependent Claim
19 words
A liquid crystal light modulation device according to claim 1 wherein said diffraction grating is an asymmetric diffraction grating.
Claim 7
Dependent Claim
40 words
A liquid crystal light modulation device according to claim 1, wherein said control means includes two electrodes arranged to sandwich the liquid crystals to control the orientation of the liquid crystals by an electric field generated by said two electrodes.
Claim 8
Dependent Claim
22 words
A liquid crystal liquid modulation device according to claim 6 wherein said liquid crystals are nematic liquid crystals having a positive dielectricity.
Claim 9
Dependent Claim
18 words
A liquid crystal liquid modulation device according to claim 1 wherein said liquid crystals are ferrodielectric liquid crystals.
Claim 10
Dependent Claim
29 words
A liquid crystal light modulation device according to claim 1 wherein said control means includes at least one heater to control the orientation of the liquid crystals by heat.
Claim 11
Dependent Claim
20 words
A liquid crystal light modulation device according to claim 1 wherein said optical element is made of a transparent insulator.
Claim 12
Dependent Claim
18 words
A liquid crystal light modulation device according to claim 1 wherein said optical element includes a transparent electrode.
Claim 13
Dependent Claim
23 words
A liquid crystal light modulation device according to claim 1 wherein each of said portions of said optical element has a reflection surface.
Claim 14
Dependent Claim
73 words
A liquid crystal light modulation device according to claim 1 wherein said control means changes the orientation of said liquid crystals; and a height T (μm) and a pitch P (μm) of said diffraction grating and a difference Δn between an extraordinary refraction index n e and an ordinary refraction index n o of the liquid crystal satisfies the following conditions for a wavelength between 350 nm and 800 nm: 0.2≦Δn·T≦7.0, and 0.8≦P≦10.
Claim 15
Dependent Claim
42 words
A liquid crystal light modulation device according to claim 13 wherein said control means includes two transparent electrodes arranged to sandwich said liquid crystals to control the orientation of said liquid crystals by an electric field generated by said two transparent electrodes.
Claim 16
Dependent Claim
23 words
A liquid crystal light modulation device according to claim 14 wherein said diffraction grating is rectangular and essentially satisfies the following condition: 0.2≦Δn·T≦1.0
Claim 17
Dependent Claim
23 words
A liquid crystal light modulation device according to claim 14 wherein said diffraction grating is triangular and essentially satisfies the following condition: 1.3≦Δn·T≦7.0
Claim 18
Dependent Claim
54 words
A liquid crystal light modulation device according to claim 1 wherein said diffraction grating has a plurality of inclined surfaces arranged at a predetermined pitch, at least 50% of a total projection area formed when said diffraction grating is projected onto said substrate being occupied by projection areas of said plurality of inclined surfaces.
Claim 19
Dependent Claim
22 words
A liquid crystal liquid modulation device according to claim 13 wherein said liquid crystals are nematic liquid crystals having a positive dielectricity.
Claim 20
Dependent Claim
84 words
A liquid crystal light modulation device according to claim 1, wherein said seconds substrate has a light exit side, and further comprising light shut-off means for transmitting therethrough a diffraction signal light diffracted by said diffraction grating and having an incident angle lower than a selected θ min an for shutting-off transmission of a diffraction non-signal light having an incident angle larger than θ min, said light shut-off means being arranged proximate to or in contact with said light-exit side of said second substrate.
Claim 21
Dependent Claim
26 words
A liquid crystal light modulation device according to claim 19 wherein said control means includes a pair of transparent electrodes arranged to sandwich said liquid crystals.
Claim 22
Dependent Claim
36 words
A liquid crystal light modulation device according to claim 20 wherein said light shut-off means includes a plurality of light wave guides having longitudinal direction thereof arranged along a direction of emission of the signal light.
Claim 23
Dependent Claim
28 words
A liquid crystal light modulation device according to claim 20 wherein said light shut-off means includes a plurality of alternately arranged light transmission members and light absorption members.
Claim 24
Dependent Claim
28 words
A liquid crystal light modulation device according to claim 20 wherein said light shut-off means includes a plurality of alternately arranged light transmission members and light scatter members.
Claim 25
Dependent Claim
21 words
A liquid crystal liquid modulation device according to claim 1, wherein said optical element is formed as part of said substrate.
Claim 26
Dependent Claim
19 words
A liquid crystal liquid modulation device according to claim 1, wherein said diffraction grating is a pedestal-shaped diffraction grating.
Claim 27
Dependent Claim
47 words
A liquid crystal liquid modulation device according to claim 1 wherein said control means includes electrode films formed on said facing sides of said first and second substrates, whereby the refractive index of said liquid crystals is changed by generating an electric field between said electrode films.
Claim 28
Dependent Claim
35 words
A liquid crystal liquid modulation device according to claim 26 wherein liquid crystal molecules of said liquid crystals are arranged in a direction parallel to said facing side in the absence of said electric field.
Claim 29
Dependent Claim
56 words
A liquid crystal light modulation device according to claim 1 wherein said device is adapted to receive an incident light entering obliquely relative to said first substrate and said control means changes the orientation of said liquid crystals so as to switch said incident light selectively to a 0-order light and a high order diffracted light.
Claim 30
Dependent Claim
152 words
A liquid crystal liquid modulation device comprising: a first substrate and a second substrate; said first substrate having a light-incident side for receiving incident light and a facing side facing said second substrate, said second substrate having a facing side facing said facing side of said first substrate, and said facing sides of said first and second substrateas being parallel with each other and spaced a predetermined distance from each other; a diffraction grating having plural portions and liquid crystals, said portions of said diffraction grating and said liquid crystals being alternately arranged between said first and second substrates, the heights of said portions of said diffraction grating and said liquid crystals in a direction normal to said facing sides being substantially the same, and said liquid crystals being separated from one another by the intervening portions of said diffraction grating; and control means for controlling an orientation of said liquid crystals.
Claim 31
Dependent Claim
152 words
A liquid crystal liquid modulation device comprising: a first substrate and a second substrate; said first substrate having a light-incident side for receiving incident light and a facing side facing said second substrate, said second substrate having a facing side facing said facing side of said first substrate, and said facing sides of said first and second substrateas being parallel with each other and spaced a predetermined distance from each other; a diffraction grating having plural portions and liquid crystals, said portions of said diffraction grating and said liquid crystals being alternately arranged between said first and second substrates, the heights of said portions of said diffraction grating and said liquid crystals in a direction normal to said facing sides being substantially the same, and said liquid crystals being separated from one another by the intervening portions of said diffraction grating; and control means for controlling an orientation of said liquid crystals.
Claim 32
Dependent Claim
24 words
A liquid crystal light modulation device according to claim 29 wherein liquid crystal molecules of said liquid crystals are arranged in a predetermined direction.
Claim 33
Dependent Claim
34 words
A liquid crystal light modulation device according to claim 30 wherein the liquid crystal molecules are arranged in said predetermined direction in accordance with fine grooves formed by said portions of the diffraction grating.
Claim 34
Dependent Claim
25 words
A liquid crystal light modulation device according to claim 29 wherein a section of said portions of the diffraction grating is of a pedestal shape.
Claim 35
Dependent Claim
56 words
A liquid crystal light modulation device according to claim 32 wherein said device is adapted to receive an incident light entering obliquely relative to said first substrate and said control means changes the orientation of said liquid crystals so as to switch said incident light selectively to a 0-order light and a high order diffracted light.
Claim 36
Dependent Claim
82 words
A liquid crystal light modulation device according to claim 29, wherein said second substrate has a light-exit side, and further comprising light shut-off means for transmitting therethrough a diffraction signal light diffracted by the diffraction grating and having an incident angle lower than a selected θ min and for shutting-off transmission of a diffraction non-signal light having an incident angle larger than θ said light shut-off means being arranged proximate to or in contact with said light-exit side of said second substrate.
Claim 37
Dependent Claim
46 words
A liquid crystal light modulation device according to claim 29 wherein said control means includes electrode films formed on said facing sides of said first and second substrates, whereby the orientation of said liquid crystals is changed by generating an electric field between said electrode films.
Claim 38
Dependent Claim
41 words
A liquid crystal light modulation device according to claim 29 wherein said control means causes said liquid crystals selectively to have at least two refractive indexes, one of said refractive indexes being substantially the same as that of said diffraction grating.
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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) | 1991-03-08 | 1991-09-07 | 1992-03-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-08 | 1995-09-07 | 1996-03-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-08 | 1999-09-07 | 2000-03-08 | $7700.00 | Window Closed / Lapsed |