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Liquid Crystal Light Modulator and Scanner

IP.com Disclosure Number: IPCOM000094863D
Original Publication Date: 1965-Jun-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Holzman, GR: AUTHOR

Abstract

Certain substances, namely liquid crystals can be put into the mesomorphic state which is intermediate the crystalline and liquid state. This state can have one or more phases namely, semetic, nematic, or cholesteric. A mesophase occasionally adopts a homeotrophic state which is optically extinct between crossed nicol prisms. The absence of birefringence in such substances does not imply the absence of anisotrophy or ordering of the molecular units. Actually, the molecules are arrayed such that the optical axis of the substance is in the same direction throughout.

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Liquid Crystal Light Modulator and Scanner

Certain substances, namely liquid crystals can be put into the mesomorphic state which is intermediate the crystalline and liquid state. This state can have one or more phases namely, semetic, nematic, or cholesteric. A mesophase occasionally adopts a homeotrophic state which is optically extinct between crossed nicol prisms. The absence of birefringence in such substances does not imply the absence of anisotrophy or ordering of the molecular units. Actually, the molecules are arrayed such that the optical axis of the substance is in the same direction throughout.

Electric and magnetic fields orient the molecules of the nematic phase such that their long axes are disposed at right angles to the applied electric field and parallel to the lines of force of an applied magnetic field. This phase is birefringent and uniaxial, with the optical axis parallel to the long axis of the molecules. Unpolarized light entering the medium is resolved into ordinary and extraordinary rays. The extraordinary ray vibrates in the plane containing the ray and optic axes.

This phenomenon can be used to form a light modulator as shown in drawing
A. Here, material 10, existing in the nematic mesomorphic state, is made homeotrophic by application of a potential to the top and bottom plates 11 and 11a and raising material 10 to the proper temperature by surrounding heating coils. The homeotrophy is modulated by changing either a part of or the whole field pattern by a transverse potential applied to plates 12a and 12b. Such misaligns the optical a...