US 5,471,327 A · Holographic diffuser for back-lit display

Abstract

A holographic diffuser for use in conjunction with a back-lit flat-panel display and a source of illumination in the form of one or more tubular lamp segments is recorded so as to receive light from the lamp segments and scatter it preferentially along a plane perpendicular to the axis of the bulbs. In a back-lit display having vertically oriented tubular lamps, the diffuser scatters substantially more in the horizontal dimension, thus filling in the gaps of light intensity between the bulbs, which would otherwise be viewed by an observer, as with conventional diffusers. The high aspect ratio diffusers of the present invention are preferably formed by projecting coherent radiation through a mask having dimensions functionally related to the desired final aspect ratio, with an optional collimating lens being used to project that mask to infinity. A contact exposure process is also described.

Claims10

Dependent claims

A backlight assembly for use with a transmissive-type flat-panel display having a back surface, the assembly comprising:

a source of backlighting including a plurality of parallel, spaced-apart, elongated lamp segments supported in a first plane;
a holographically recorded diffuser operatively disposed between the lamp segments and the display panel, in a second plane, the distance between the segments and the two planes defining a lamp geometry, the geometry associated with the recording of the diffuser being a function of the lamp geometry, resulting in a diffuser operative to receive light from the segments over a range of angles of incidence, and redirect the light toward the back surface of the display with an asymmetric scattering pattern characterized in that the angle of scattering is substantially greater within a plane perpendicular to the longitudinal direction of the lamp segments as compared to the direction parallel to the lamp segments, so as to fill in gaps of illumination Which would otherwise be visually evident in the display between said lamp segments.

Dependencies are inferred from the claim text.

Holographic diffuser for back-lit display

Life of this patent

Holographic diffuser for back-lit display

Life of this patent

Abstract

Claims10