Fiber-optic faceplate with tilted fibers
AssigneeHewlett-Packard Company
InventorsHenryk Birecki, Laurence M. Hubby, Jr.
Life of this patent
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Abstract
Significantly improving in the contrast ratio of a visual image display using a liquid crystal layer and a fiber optic faceplate with tilted fibers. One preferred embodiment of the visual image display includes a liquid crystal layer, a first polarizer and an optical fiber faceplate with many substantially parallel fibers. Each fiber has an axis which forms an oblique angle with the normal to the front surface of the liquid crystal layer. All the oblique angles are substantially equal to a typical oblique angle. The typical oblique angle is selected along the direction that substantially maximizes the contrast ratio of the display.
Claims12
A visual image display comprising:
- a liquid crystal layer having a front surface and a contrast ratio that depends on the viewing direction from the front surface;
- a first polarizer, having a front surface, located adjacent to the front surface of the liquid crystal layer;
- and
- an optical fiber faceplate having a front surface and a plurality of substantially parallel optical fibers, the faceplate located adjacent to the front surface of the first polarizer, each fiber having an axis which forms an oblique angle with the normal to the front surface of the liquid crystal layer, the oblique angles of all the fibers being substantially equal to a typical oblique angle;
- wherein:
- the typical oblique angle is selected according to the directional dependency of the contrast ratio of the liquid crystal layer to substantially maximize the contrast ratio of the liquid crystal layer to improve the contrast ratio of the display.
A method to improve the contrast ratio of a visual image display that has a liquid crystal layer, with a front surface and a contrast ratio that depends on the viewing direction from the front surface, the liquid crystal layer being adjacent to a first polarizer which is adjacent to an optical fiber faceplate, the faceplate having a plurality of substantially parallel optical fibers, each fiber having an axis which forms an oblique angle with the normal to the front surface of the liquid crystal layer, all the oblique angles being substantially equal to a typical oblique angle, the method comprising the steps of:
- determining the refractive index of the faceplate;
- measuring the directional dependency of the contrast ratio of the liquid crystal layer;
- identifying the direction with substantially the largest contrast ratio;
- and
- selecting the typical oblique angle to be substantially along the direction of the liquid crystal layer with the largest contrast ratio corrected by the refractive index, so as to improve the contrast ratio of the display.
Dependencies are inferred from the claim text.