US4767194A
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US
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Blue phase liquid crystal system, method of operation and its use
Assignee: Merck Patent GmbH
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Filing: 1987-06-08
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Granted: 1988-08-30
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Expires: 2007-06-08
Abstract
Abstract An optical system contains a liquid crystal cell (1), to the liquid crystal layer (11) of which an E-field can be applied transversely to the plane of the layer. A light source (3) sends to the liquid crystal cell (1) a beam of rays parallel to the field direction. The liquid crystal is in the form of a chiral, optically isotropic phase ("blue phase"). This phase has a field-dependent optical density for the incident light and is matched to the light wavelength such that no selective reflection takes place. Such a cell is also optically isotropic in the presence of an E-field, switches rapidly and requires no interface orientation. Its preferred fields of use are: intensity modulation of light of a given wavelength, or as a phase grid in a schlieren-optical system, an etalon in a laser, or a light switch.
Inventors
- 👤 Gerd Heppke
- 👤 Feodor Oestreicher
- 👤 Heinz-Siegfried Kitzerow
- 👤 Michael Krumrey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:32
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/1313; G02F1/137
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
183 words
An optical system for modifying light transmitted therethrough comprising: (1) a liquid crystal cell comprising (a) two polarizer-free carrier plates facing one another, each having on its surface facing the other, a patterned electrode, and (b) a liquid crystal layer enclosed between the carrier plates; (2) an AC voltage source operationally connected to the electrodes and which in operation produces in the liquid crystal layer an electrical field which is directed essentially perpendicularly to the plane of the layer; (3) a light source placed in front of the liquid crystal cell which in operation impinges a beam of light onto the liquid crystal cell in a direction which essentially corresponds to the direction of the electric field, said light consisting essentially of a frequency or frequencies to which the liquid crystal layer is essentially transparent and has a field-dependent optical density; and (4) an optical element utilizing the light transmitted through the liquid crystal layer, wherein the liquid crystal layer is in a blue phase during operation of the system and does not selectively filter out wavelength components of the light passing through.
Claim 2
Dependent Claim
183 words
An optical system for modifying light transmitted therethrough comprising: (1) a liquid crystal cell comprising (a) two polarizer-free carrier plates facing one another, each having on its surface facing the other, a patterned electrode, and (b) a liquid crystal layer enclosed between the carrier plates; (2) an AC voltage source operationally connected to the electrodes and which in operation produces in the liquid crystal layer an electrical field which is directed essentially perpendicularly to the plane of the layer; (3) a light source placed in front of the liquid crystal cell which in operation impinges a beam of light onto the liquid crystal cell in a direction which essentially corresponds to the direction of the electric field, said light consisting essentially of a frequency or frequencies to which the liquid crystal layer is essentially transparent and has a field-dependent optical density; and (4) an optical element utilizing the light transmitted through the liquid crystal layer, wherein the liquid crystal layer is in a blue phase during operation of the system and does not selectively filter out wavelength components of the light passing through.
Claim 3
Dependent Claim
26 words
A system of claim 1, wherein the local dielectric anisotropy of the liquid crystal layer has a positive value greater than 3 in the field-free state.
Claim 4
Dependent Claim
26 words
A system of claim 1, wherein the local dielectric anisotropy of the liquid crystal layer has a positive value greater than 7 in the field-free state.
Claim 5
Dependent Claim
26 words
A system of claim 1, wherein the local dielectric anisotropy of the liquid crystal layer has a negative value less than -1 in the field-free state.
Claim 6
Dependent Claim
26 words
A system of claim 1 wherein the local dielectric anisotropy of the liquid crystal layer has different signs above and below a certain alternating voltage frequency.
Claim 7
Dependent Claim
23 words
A system of claim 1 wherein the liquid crystal layer is a mixture of at least one nematic component and one chiral component.
Claim 8
Dependent Claim
19 words
A system of claim 1 wherein the liquid crystal layer has a thickness of 20 μm to 250 μm.
Claim 9
Dependent Claim
19 words
A system of claim 1 wherein the liquid crystal layer has a thickness of 25 μm to 100 μm.
Claim 10
Dependent Claim
19 words
A system of claim 1 wherein the frequency of the alternating voltage is 30 Hz to 10 5 Hz.
Claim 11
Dependent Claim
19 words
A system of claim 1 wherein the frequency of the alternating voltage is 500 Hz to 10 4 Hz.
Claim 12
Dependent Claim
14 words
A system of claim 9 wherein the alternating voltage is a square wave voltage.
Claim 13
Dependent Claim
36 words
In an optical system for intensity modulation of light of a certain wavelength comprising a liquid crystal cell, a voltage source and a light source, the improvement wherein the optical system is that of claim 1.
Claim 14
Dependent Claim
27 words
In a schlieren-optical system, comprising a liquid crystal cell, a voltage source and a light source, the improvement wherein the optical system is that of claim 12.
Claim 15
Dependent Claim
21 words
In a display system for showing motion pictures, the improvement wherein the display system comprises a schlieren-optical system of claim 13.
Claim 16
Dependent Claim
31 words
In an optical system effective as a lens comprising a liquid crystal cell, a voltage source and a light source, the improvement wherein the optical system is that of claim 12.
Claim 17
Dependent Claim
13 words
An optical system of claim 15 wherein the light source is a laser.
Claim 18
Dependent Claim
35 words
In an optical system effective as a lens of variable focal length, comprising a liquid crystal cell, a voltage source and a light source, the improvement wherein the optical system is that of claim 12.
Claim 19
Dependent Claim
32 words
In an optical system effective as a light switch, comprising a liquid crystal cell, a voltage source and a light source, the improvement wherein the optical system is that of claim 12.
Claim 20
Dependent Claim
15 words
An optical system of claim 1 wherein the liquid crystal phase is a blue phase.
Claim 21
Dependent Claim
17 words
A method of influencing light comprising directing the light onto the liquid crystal cell of claim 1.
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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) | 1991-08-30 | 1992-02-29 | 1992-08-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-30 | 1996-02-29 | 1996-08-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-30 | 2000-02-29 | 2000-08-30 | $7700.00 | Window Closed / Lapsed |