US6014192A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Illumination device and application thereof to the illumination of a transmissive screen
Assignee: Thales SA
•
Filing: 1997-07-16
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Granted: 2000-01-11
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Expires: 2017-07-16
Abstract
Abstract An illumination device comprises a light source coupled to a waveguide. the waveguide comprises a diffracting element capable of diffracting emergent light rays coming from the source, in a direction substantially perpendicular to the surface of the waveguide. A device of this kind is particularly well-suited to transmissive display screens of the liquid crystal display screen type. It can generate a highly collimated, polarized light.
Inventors
- 👤 Jean-Claude Lehureau
- 👤 Cecile Joubert
- 👤 Brigitte Loiseaux
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 08:17
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/0001; G02B6/0011; G02B6/0033; F; F21; F21V; F21V9/00; F21V9/14; G02B6/0035; G02B6/0045; G02B6/0046; G02B6/0056; G02B6/0075; G02B6/0076; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/1336; G02F1/13362
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
80 words
An illumination device comprising: a light source outputting light rays at a plurality of angles; and a light waveguide coupled with said light source, wherein the light waveguide comprises a diffracting element located within the waveguide to diffract emergent ones of said light rays having angles of incidence between 90° and a limit angle of reflection at an output of said waveguide to provide output light rays which are in a direction substantially perpendicular to a surface of the waveguide.
Claim 2
Dependent Claim
80 words
An illumination device comprising: a light source outputting light rays at a plurality of angles; and a light waveguide coupled with said light source, wherein the light waveguide comprises a diffracting element located within the waveguide to diffract emergent ones of said light rays having angles of incidence between 90° and a limit angle of reflection at an output of said waveguide to provide output light rays which are in a direction substantially perpendicular to a surface of the waveguide.
Claim 3
Dependent Claim
15 words
An illumination device according to claim 1, wherein the diffracting element is a holographic element.
Claim 4
Dependent Claim
38 words
An illumination device according to claim 1, wherein the waveguide has an optical index grating organized in strata oriented in a direction forming an angle substantially equal to 45° with the normal to the plane of the waveguide.
Claim 5
Dependent Claim
56 words
An illumination device according to claim 1, wherein the diffracting element comprises: an etched grating, the etchings having flanks with refraction indices at about 45° to the normal to the surface of the waveguide and flanks parallel to the normal to the plane of the waveguide; a resonant cavity into which the etched grating is integrated.
Claim 6
Dependent Claim
42 words
An illumination device according to claim 4, wherein the etched grating is covered with a layer of material having a refraction index n2, the entire unit being integrated into a material having the same refraction index n1 as that of the grating.
Claim 7
Dependent Claim
58 words
An illumination device according to one of the claims 1 to 5, wherein the diffracting element transmits a s polarized light defined perpendicularly to the plane of incidence and diffracts a p polarized light defined perpendicularly to the plane of incidence and wherein said diffracting element comprises means to convert the s polarized light into p polarized light.
Claim 8
Dependent Claim
53 words
An illumination device according to claim 6 comprising, at the end of the waveguide opposite the light source, a quarter-wave plate and a mirror parallel to said quarter-wave plate, and also comprising a mirror located in a plane parallel to the surface of the waveguide and opposite the plane of extraction of light.
Claim 9
Dependent Claim
52 words
An illumination device for a display screen, comprising a superimposition of three illumination devices according to claim 1, a first device comprising a light source emitting in the red, a second device comprising a light source emitting in the green and a third device comprising a light source emitting in the blue.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-01-10 | 2003-07-12 | 2004-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-01-10 | 2007-07-12 | 2008-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-01-10 | 2011-07-12 | 2012-01-11 | $7700.00 | Window Closed / Lapsed |