FRONT ILLUMINATION DEVICE COMPRISING A FILM-BASED LIGHTGUIDE
First Claim
1. A reflective display comprising:
- a. a reflective spatial light modulator; and
b. a frontlight comprising;
i) 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;
a) each coupling lightguide terminates in a bounding edge; and
b) each coupling lightguide is folded in a fold region such that the bounding edges are stacked;
ii) at least one light source disposed to emit light into the stacked bounding edges, the light propagating within the coupling lightguides to the lightguide region of the lightguide, with light from each coupling lightguide combining and totally internally reflecting within the lightguide region;
iii) a plurality of light extraction features that frustrate totally internally reflected light within the lightguide region such that the light exits the lightguide toward the reflective spatial light modulator in a light emitting region of the film;
iv) a cladding region optically coupled on a first side to the lightguide wherein light from the at least one light source propagates into the cladding region; and
v) a light extracting region operatively coupled to the cladding region on a second side of the cladding region opposite the lightguide,wherein a portion of light in the cladding region is extracted by the light extracting region.
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Accused Products
Abstract
A reflective display includes a reflective spatial light modulator and a frontlight. The frontlight includes a lightguide formed from a film. The lightguide includes an array of coupling lightguides continuous with a lightguide region of the lightguide. One or more light sources emit light into the array of coupling lightguides. Light from each coupling lightguide combines and totally internally reflects within the lightguide region. Light extraction features frustrate totally internally reflect light within the lightguide region such that the light exits the lightguide toward the reflective spatial light modulator in a light emitting region of the film. A cladding region is optically coupled to the lightguide so light from the light source propagates into the cladding region. A light extracting region is operatively coupled to the cladding region opposite the lightguide, and light in the cladding region is extracted. A method of producing a display is also disclosed.
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Citations
24 Claims
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1. A reflective display comprising:
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a. a reflective spatial light modulator; and b. a frontlight comprising; i) 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; a) each coupling lightguide terminates in a bounding edge; and b) each coupling lightguide is folded in a fold region such that the bounding edges are stacked; ii) at least one light source disposed to emit light into the stacked bounding edges, the light propagating within the coupling lightguides to the lightguide region of the lightguide, with light from each coupling lightguide combining and totally internally reflecting within the lightguide region; iii) a plurality of light extraction features that frustrate totally internally reflected light within the lightguide region such that the light exits the lightguide toward the reflective spatial light modulator in a light emitting region of the film; iv) a cladding region optically coupled on a first side to the lightguide wherein light from the at least one light source propagates into the cladding region; and v) a light extracting region operatively coupled to the cladding region on a second side of the cladding region opposite the lightguide, wherein a portion of light in the cladding region is extracted by the light extracting region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A reflective display comprising:
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a reflective spatial light modulator; and a frontlight comprising; a lightguide foamed from a film having a thickness not greater than 0.5 millimeters, the lightguide comprising an array of coupling lightguides extending from a lightguide region of the lightguide, the array of coupling lightguides folded in a fold region and stacked to form a light input surface; a light source disposed to emit light into the light input surface, the light propagating within the array of coupling lightguides to the lightguide region, with light from each coupling lightguide of the array of coupling lightguides combining and totally internally reflecting within the lightguide region; a plurality of light extraction features operatively coupled to the film and configured to frustrate the totally internally reflected light within the lightguide region such that the light exits the frontlight in a light emitting region toward the reflective spatial light modulator; a cladding region optically coupled to the lightguide; a light extracting region operatively coupled to the cladding region on a first side of the cladding region opposite the lightguide, wherein light propagating in each coupling lightguide at a first angle from a total internal reflection interface is propagating at a larger angle after the fold region in the coupling lightguide and is extracted from the cladding region by the light extracting region. - View Dependent Claims (20, 21)
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22. A method of producing a display, said method comprising:
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a. fowling an array of coupling lightguides from a lightguide region of a film comprising a core region and a cladding region by separating each coupling lightguide of the array of the coupling lightguides from each other such that each coupling lightguide remains continuous with the lightguide region and comprises a bounding edge at the end of the coupling lightguide; b. folding the array of coupling lightguides such that the bounding edges are stacked; c. positioning a light source to direct light into the stacked bounding edges such that the light propagates within the core region through the array of coupling lightguides and the lightguide region by total internal reflection; d. forming a plurality of light extraction features on or within the core layer in a light emitting region of the lightguide region; e. disposing a light extracting region on the cladding region or optically coupling a light extracting region to the cladding region in a light mixing region of the lightguide region between the array of coupling lightguides and the light emitting region; and f. positioning the light emitting region adjacent a reflective spatial light modulator. - View Dependent Claims (23, 24)
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Specification