Browse Prior Art Database

Light To Heat Converter

IP.com Disclosure Number: IPCOM000052828D
Original Publication Date: 1981-Jul-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Stuckert, PE: AUTHOR

Abstract

Laser-addressed liquid crystal displays of the type described in [*] are written with heat in the form of light. The converter disclosed herein has gain and reduces the amount of light required for writing.

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Light To Heat Converter

Laser-addressed liquid crystal displays of the type described in [*] are written with heat in the form of light. The converter disclosed herein has gain and reduces the amount of light required for writing.

Laser-addressed liquid crystal displays of the type described in [*] are written as shown in Fig. 1. A beam of light of wavelength a is directed to the back of the liquid crystal assembly where it is absorbed in an antireflection layer (which is frequently silicon). Some of the heat thus generated is transferred, via the aluminum, to the liquid crystal where it alters the liquid crystal arrangement to produce a light-scattering region. A multiplicity of light-scattering regions comprise a display which is viewed by projection from the front of the assembly, using the aluminum surface as a mirror, as described in [*]. Provision of sufficient light to operate this display is a significant problem.

Fig. 2 shows the disclosed liquid crystal assembly in which the silicon layer is fabricated as a planar PN junction, which, biassed by a voltage E(B), is a planar photodiode. Operation is identical to that of the structure shown in Fig. 1 except that the incident light now produces hole-electron pairs. With E(B) applied, the electrons are attracted to the N region where the absorption of their kinetic energy produces the required heat with a gain of See Original One example should suffice: With lambda=0.8 mu m, E(B)=50 V and QE=50%, K(H)=1 Thus,...