Reflective spatial light modulator display with stacked light guides and method

摘要

A reflective display includes a reflective spatial light modulator and a front light having a lightguide formed by an array of film-based lightguides coupled into a lightguide region of the lightguide. One or more light sources emit light into the array of lightguides, with light extraction features frustrating totally internally reflect light within the lightguide region such that the light exits the lightguide through a cladding region toward a light redirecting optical element that redirects the light toward a reflective spatial light modulator.

主权项

1. A display comprising:
a. a reflective spatial light modulator comprising a reflective surface; b. a lightguide formed from a film having opposing faces with a thickness not greater than about 0.5 millimeters therebetween, the lightguide having an array of coupling lightguides continuous with a lightguide region of the lightguide, wherein:
i). each coupling lightguide of the array of coupling lightguides terminates in a bounding edge; andii). each coupling lightguide is folded in a fold region such that the bounding edges of the array of coupling lightguides are stacked; c. a light source disposed to emit light into the stacked bounding edges, the light propagating within the array of coupling lightguides to the lightguide region, with light from each coupling lightguide combining and totally internally reflecting within the lightguide region; d. a cladding region having a first side optically coupled to the lightguide and an opposing second side; e. a light redirecting optical element optically coupled to the second side of the cladding region; and f. a plurality of light extraction features arranged in a pattern that varies spatially in a light emitting region of the lightguide, each of the plurality of light extraction features to frustrate totally internally reflected light within the lightguide region such that frustrated totally internally reflected light exits the lightguide in the light emitting region into the cladding region with a first angle of peak luminous intensity in the cladding region and a first angular full-width at half-maximum intensity in a first output plane in the cladding region, wherein the light redirecting optical element redirects the frustrated totally internally reflected light exiting the lightguide toward the reflective spatial light modulator such that the frustrated totally internally reflected light after redirection has a second angle of peak luminous intensity different from the first angle of peak luminous intensity and the second angle of peak luminous intensity is within an angular range from 0 to 30 degrees from a direction perpendicular to the reflective surface of the reflective spatial light modulator.