LIQUID CRYSTAL DEVICE COMPRISING CHIRAL NEMATIC LIQUID CRYSTAL MATERIAL IN A HELICAL ARRANGEMENT
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Abstract
This invention generally relates to a liquid crystal device, and more particularly to such a device in the form of a liquid crystal cell such as for a display device, and further relates to a display device having the liquid crystal device, an optical waveguide device comprising the liquid crystal device, a Variable Optical Attenuator comprising the liquid crystal device, an optical switch comprising the liquid crystal device, a method of controlling transmission of polarised light, and to a further liquid crystal device. A liquid crystal device for controlling transmission of polarised light, comprising: chiral nematic liquid crystal having a helical arrangement of liquid crystal molecules in the absence of an electric field; and at least two electrodes for applying an electric field having a component normal to the helical axis of the chiral nematic liquid crystal, wherein the chiral nematic liquid crystal has negative dielectric anisotropy.
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Citations
95 Claims
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1-67. -67. (canceled)
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68. A liquid crystal device for controlling transmission of polarised light, comprising:
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chiral nematic liquid crystal having a helical arrangement of liquid crystal molecules in the absence of an electric field; and at least two electrodes for applying an electric field having a component normal to the helical axis of the chiral nematic liquid crystal, wherein the chiral nematic liquid crystal has negative dielectric anisotropy. - View Dependent Claims (72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90)
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69. A liquid crystal device for controlling transmission of light, comprising:
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a light source to emit said light; chiral nematic liquid crystal having a helical arrangement of liquid crystal molecules in the absence of an electric field; and at least two electrodes for applying an electric field having a component normal to the helical axis of the chiral nematic liquid crystal, wherein the chiral nematic liquid crystal has negative dielectric anisotropy and is liquid crystal having pitch shorter than a shortest wavelength of said light.
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70. A liquid crystal device for controlling outputting of light from said device, the device comprising:
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chiral nematic liquid crystal having a helical arrangement of liquid crystal molecules and having positive dielectric anisotropy; at least two electrodes for applying an electric field having a component normal to the helical axis of the chiral nematic liquid crystal molecules, the chiral nematic preferably having pitch shorter than a shortest wavelength of said light; the liquid crystal such that the helical arrangement of molecules rotates towards alignment with the electric field, preferably to align with the local electric field, wherein the liquid crystal is provided in a composition further comprising polymer.
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71. A liquid crystal device for controlling output of light from the device, the device comprising chiral nematic liquid crystal having a helical arrangement of liquid crystal molecules and having positive dielectric anisotropy and further comprising at least two electrodes for applying an electric field normal to the helical axis of the chiral nematic liquid crystal molecules, the device comprising:
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the liquid crystal such that, in the absence of the electric field, the orientation of the helical arrangement and optic axis of the chiral liquid crystal is such that the polarisation state of any linearly polarised light incident on the device is perpendicular to the optic axis and helical arrangement, and the liquid crystal comprised in a composition having polymer, the polymer preferably being to a concentration of between about 0.1% and about 30% w/w in the host chiral liquid crystal; the liquid crystal such that application of the electric field rotates the helical arrangement and optical axis of the chiral nematic liquid crystal to align, or partially align, to a plane defined by the electrodes; the liquid crystal such that, after removal of the electric field, the optical axis and helical arrangement relax back to the state before the electric field was applied.
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91. Method of controlling outputting of light from a liquid crystal device, comprising:
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applying an electric field to a helical arrangement of liquid crystal molecules of chiral nematic liquid crystal of said device; and said helical arrangement rotating to align the helical axis of the arrangement to said electric field, wherein said chiral nematic liquid crystal has negative dielectric anisotropy and said helical arrangement has helical pitch of less than 380 nm. - View Dependent Claims (92, 93, 94, 95)
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Specification