The liquid crystal light valve - A new display device

The liquid crystal light valve (LCLV) is a photoactivated electro-optic device that is designed to transfer images from one beam of light to another. It is being developed primarily for application to large screen video display of both alpha numeric/graphic and pictorial television imagery. However, it is also useful in the conversion of images from non-coherent to spatially coherent light, and from visible to IR light. Basically the device consists of a glass substrate upon which is deposited thin films of indium-tin oxide, a CdS photo-sensor, a CdTe light-absorbing layer, and a dielectric mirror. A second glass substrate is coated with a thin film indium-tin oxide transparent electrode. The two substrates sandwich between them a thin layer of an appropriate nematic liquid crystal. The resulting device has several important features. It has high input sensitivity (<100 µW/cm²at 525 nm), high resolution (>1500 lines/inch at 50 percent MTF), high contrast (>100:1), television-compatible speed (30 frames/sec.). Moreover, it is capable of very substantial image intensification (>10⁵). Devices having apertures of two inches are fabricated routinely on fiber optics substrates. These devises can then be coupled directly to a 2- inch diameter fiber optics faceplate CRT primary (input) display to constitute a compact device package. In this talk we will describe the basic light valve device, discuss the various liquid crystal electro-optic effects that we use in these devices and characterize the performance that we obtain from them.