 Image reading apparatus |
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| Beam scanning system adopting deflection disc |
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| Carrier film and process for producing the same |
| It is an object of the present invention to provide a carrier film in which a cover resist layer is ... |
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| High-efficiency polarized light source |
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| System for the display of images given by a spatial modulator with transfer of energy |
| This is why the invention relates to a system for the display of images comprising: a spatial ... |
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| Fiber optic diffraction grating maker |
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| Method and apparatus for maximizing the visual quality of image presented in electric form |
| OF THE INVENTION Referring to the block diagram in FIG. 1, the procedure of the invention works as ... |
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| Encoded security document |
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| Side alignment mark |
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Method for making an optical device using a laser beam interference pattern
| Details |
Inventors: Tanaka, Keiji; Kato, Kinya; Tsuru, Shinji; Sakai, Shigenobu;
Assignee: Nippon Telegraph and Telephone Corporation (Tokyo, JP)
Primary Examiner: Sikes; William L.
Assistant Examiner: Nguyen; Tiep H.
Attorney, Agent or Firm: Finnegan, Henderson, Farabow, Garrett & Dunner, L.L.P.
A polymer dispersed liquid crystal optical device is presented which has optical elements which control reflection, transmission and diffraction of incident light entering the device by adjusting the magnitude of the electrical field applied to the device between a maximum and a minimum limits. An optical element consists of a polymer material having an electrical field-independent refractive index, and a liquid crystal material having an electrical field-dependent refractive index. The optical elements are distributed through the device at specific inter-element spacings, thus enabling to generate reflection of incident light in accordance with Bragg's law of reflection. The inter-element spacings can also be varied by the application of the field, thus enabling to generate reflection of light of a desired wavelength. Such optical elements are ideal for use in full color optical display apparatus of a matrix driven type. Methods for producing the optical device and optical display apparatus are also presented. |
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DETAILED DESCRIPTION To resolve the above described problems in the existing state of the art of the display devices based on polymer dispersed liquid crystal technology, the present invention provides an optical device comprising a plurality of optical elements each optical element consisting of a polymer material having a refractive index which is independent of applied electrical field, and a liquid crystal material having a field-dependent refractive index different from that of the polymer material.
The optical elements are disposed in the optical device so as to have at least one periodicity in the inter-element spacing.
The value of the field-dependent refractive index is dependent on the amount of liquid crystal material contained in the optical element, and the distribution can be changed by altering the forming conditions of the optical element.
One of the features of the present invention is that the difference in the values of the refractive indexes of the polymer material and the liquid crystal material is maximized by producing the optical element from a mixture solution of a nematic liquid crystal with a light polymerized resin containing polyene and polythiol.
It is possible to produce an optical element having about 100 nm dimension, and by appropriately varying the polymerizing condition of the mixture solution, the dimension can be adjusted to provide an optical device responsive to light suitable for use in optical communications technology.
The present invention, therefore, presents an optical device comprising a pair of transparent electrodes; a plurality of optical elements, having a periodicity in the inter-element spacings, disposed between the transparent electrodes; wherein an optical element comprises one optical material having a refractive index and another optical material having an electrical field-dependent refractive index, and wherein the optical elements are orientated at a specific angle to an incident surface of the optical device, and reflection, transmission and diffraction of incident light entering the optical device are regulated by the application of an electrical field between the transparent electrodes
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Optical Systems 
