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Browse Prior Art Database

Visual Display Unit using Laser Scanner and Liquid Crystal Cell

IP.com Disclosure Number: IPCOM000087425D
Original Publication Date: 1977-Jan-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 76K

Publishing Venue

IBM

Related People

Cunningham, EA: AUTHOR [+4]

Abstract

Fig. 1 shows a semi-diagrammatic approximately full-size side view of a visual display unit 10 having a housing 11 and a rigid baseplate 12. Light source 20 includes GaAs infrared semiconductor laser 21 having light-emitting junction 22. Fiber-optic cylindrical lens 23 focuses beam 24 to a line in the plane of Fig. 1.

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Visual Display Unit using Laser Scanner and Liquid Crystal Cell

Fig. 1 shows a semi-diagrammatic approximately full-size side view of a visual display unit 10 having a housing 11 and a rigid baseplate 12. Light source 20 includes GaAs infrared semiconductor laser 21 having light-emitting junction
22. Fiber-optic cylindrical lens 23 focuses beam 24 to a line in the plane of Fig.


1.

Lens 25 and a fixed hologram deflector project this line onto deflector 30. Motor 31 and drive train 32 rotate a hologram plate 33 by means of shaft 34. As shown more clearly in Fig. 2, plate 33 contains a number of peripheral segments
35. Each segment 35 contains a conventional transmission hologram capable of deflecting output beam 36 in the direction of arrow 37 (i.e., perpendicular to the plane of Fig. 1) as plate 33 rotates in direction 38. At the end of each segment 35, beam 36 begins another scan as the next segment intercepts input beam 24.

Lens assembly 39 (Fig. 1) focuses beam 36 to a point on liquid-crystal cell 40, shown in cross section in Fig. 3. Beam 36 is transmitted through thin glass plate 41 to heat-absorbing material 42. Cavity 43 is filled with, e.g., a nematic mesomorphic liquid. The crystalline phase of this liquid is clear as at regions 44. Light-reflective electrode 45 and transparent electrode 46, which is backed by another glass plate 47, may be used to erase any images in the liquid.

Region 48, however, is heated by beam 36 sufficiently to cause a phase trans...