Hughes Aircraft Company

Other

William R Lichty

John E Gunther

William C Hoffman

Lacy G Cook

John J Ferrer

Michael N Ernstoff

In a liquid crystal image display system, a fiber optic faceplate which transmits light only through a well defined acceptance cone is optically coupled to the liquid crystal display surface of a reflective dynamic scattering mode liquid crystal display device. In an image projector embodiment, light from an external light source is directed through the faceplate onto the liquid crystal display surface. Light scattered by activated (on-state) regions of the liquid crystal is substantially absorbed by the faceplate while light reflected from the non-activated (off-state) regions of the display surface is transmitted back through the faceplate to a projection lens which forms an image on a viewing screen. In a second embodiment of the invention, a viewer directly observes the liquid crystal display surface under ambient light from either natural or artificial light sources. By absorbing light from unwanted sources outside its transmission acceptance cone, the faceplate prevents loss of image contrast while transmitting light from sources within its acceptance cone needed to illuminate the display.

Liquid crystal display system using fiber optic faceplates

In an electro-optical display device, a fiber optic faceplate which transmits light only through a well-defined solid angle, is optically coupled to an electro-optical display panel having a specularly reflecting surface. The display panel can be either an active device, such as laser diodes, or passive such as a dynamic scattering liquid crystal device. The axes of the optical fibers comprising the faceplate are slanted to the display surface at an angle such that the light which enters the front surface of the faceplate and is specularly reflected from the display surface is trapped within the faceplate. However, light emitted or scattered from on-state display elements is transmitted through the faceplate to the viewer. A high contrast display results because off-state display elements on the display surface appear dark under even intense ambient illumination whereas the on-state elements appear bright. The faceplate has two major opposing surfaces which are aligned to one another at a predetermined angle in order to control the size and direction of the display field of view.

Fiber optic light traps for electro-optical display devices

There is disclosed a liquid crystal image projector which is suitable for use as an image source in an aircraft head-up display system. In this application, the projector provides extremely bright and high contrast symbology for the aircraft pilot. More generally, the projector has application wherever a television-type raster and/or calligraphic symbology display is needed. The increase in brightness and contrast ratio is achieved by using a reflector to concentrate light from a light source onto the liquid crystal display cell from whence it is reflected through an optical aperture stop in the reflector to the projecting lens and thence to a viewing surface.

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Culver City, CA, United States of America

William R Lichty