Integrated light pipe for optical projection

Patent metadata

Field	Value
Publication number	US-9939721-B2
Application number	US-201715691762-A
Country	US
Kind code	B2
Filing date	Aug 31, 2017
Priority date	Sep 13, 2015
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

Abstract

An optical device includes a first plate having a first transparent region defining an exit face of the device, and a second plate having a second transparent region defining an entrance face of the device. At least one lens is formed over at least one of the first and second transparent regions. First and second planar reflectors are spaced apart and fixed between the first and second plates in mutually-parallel orientations diagonal to the first and second plates, thereby defining an optical path through the device from the entrance face, reflecting from the first and second reflectors, through the exit face and passing through the at least one refractive surface.

First claim

The invention claimed is:

1. An optical device, comprising:
a first plate having a first transparent region defining an exit face of the device;
a second plate having a second transparent region defining an entrance face of the device;
at least one lens formed over at least one of the first and second transparent regions; and
first and second planar reflectors, spaced apart and fixed between the first and second plates in mutually-parallel orientations diagonal to the first and second plates,
thereby defining an optical path through the device from the entrance face, reflecting from the first and second reflectors, through the exit face and passing through the at least one lens.

2. The device according to claim 1 , wherein the at least one lens comprises at least a first lens formed over the first transparent region and at least a second lens formed over the second transparent region.

3. The device according to claim 1 , wherein the at least one lens comprises at least first and second lenses formed on opposing sides of at least one of the first and second plates.

4. The device according to claim 1 , wherein the first and second plates and the first and second planar reflectors define a cavity that contains the optical path, and
wherein the device comprises third and fourth plates, which are fixed to the first and second plates and the first and second planar reflectors on opposing sides of the device in an orientation perpendicular to the first and second plates and the planar reflectors so as to enclose the cavity.

5. The device according to claim 1 , and comprising:
a patterning element;
a first spacer, fixed between the patterning element and the first plate so as to hold the patterning element in proximity to the exit face;
a light source mounted on a substrate; and
a second spacer, fixed between the substrate and the second plate so as to hold the light source in proximity to the entrance face, so that light emitted from the light source passes through the device along the optical path and transilluminates the patterning element, thereby generating patterned light.

6. A method for producing an optical device, the method comprising:
fixing together first and second planar reflectors in mutually-parallel orientations with a predefined spacing between the first and second planar reflectors;
providing first and second plates having respective first and second transparent regions that respectively define exit and entrance faces of the device, with at least one lens formed over at least one of the first and second transparent regions; and
fixing the first and second plates to the fixed-together planar reflectors in an orientation diagonal to the planar reflectors, so as to define an optical path through the device from the entrance face, reflecting from the first and second reflectors, through the exit face and passing through the at least one lens.

7. The method according to claim 6 , wherein the at least one lens comprises at least a first lens formed over the first transparent region and at least a second lens formed over the second transparent region.

8. The method according to claim 6 , wherein the at least one lens comprises at least first and second lenses formed on opposing sides of at least one of the first and second plates.

9. The method according to claim 6 , wherein providing the first and second plates comprises forming an array of lenses on a transparent substrate, and dicing the transparent substrate to produce at least one of the first and second plates with the at least one lens formed thereon.

10. The method according to claim 9 , wherein the array of lenses is formed by molding or replication on the transparent substrate.

11. The method according to claim 9 , wherein fixing together the first and second planar reflectors comprises fixing together multiple pairs of the planar reflectors so as to define multiple optical devices having respective optical cavities, and
wherein fixing the first and second plates comprises attaching the transparent plate to the multiple pairs of the planar reflectors so that the lenses in the array are respectively aligned with the optical cavities before dicing the transparent substrate.

12. The method according to claim 6 , and comprising, before fixing together the first and second planar reflectors, polishing and applying a reflective coating to respective inner surfaces of the planar reflectors from which the optical path is to reflect within the device.

13. The method according to claim 6 , wherein the first and second plates and the first and second planar reflectors define a cavity that contains the optical path, and
wherein the method comprises fixing third and fourth plates to the first and second plates and the first and second planar reflectors on opposing sides of the device in an orientation perpendicular to the first and second plates and the planar reflectors so as to enclose the cavity.

14. The method according to claim 13 , wherein fixing together the first and second planar reflectors comprises:
bonding a pair of reflective sheets to opposing sides of spacers having a thickness equal to the predefined spacing;
dicing the bonded reflective sheets and spacers along a first direction perpendicular to the spacers to produce a set of strips;
arranging the set of strips side-by-side;
bonding the third and fourth plates to opposing sides of the arranged set of the strips;
dicing the set of the strips and the third and fourth plates that are bonded thereto along a second direction diagonal to the strips so as to produce multiple rows of diagonal cavities; and
dicing apart the cavities in each of the multiple rows to produce the fixed-together planar reflectors.

15. The method according to claim 14 , wherein fixing the first and second plates to the fixed-together planar reflectors comprises, before dicing apart the cavities:
arranging the multiple rows of the diagonal cavities side by side; and
bonding the first and second plates to opposing sides of the arranged multiple rows, with an array of lenses on at least one of the first and second plates aligned with the cavities,
wherein dicing apart the cavities comprises dicing apart the first and second plates and the aligned lenses together with the cavities to which they are fixed.

16. The method according to claim 6 , and comprising:
fixing a patterning element in proximity to the exit face; and
fixing a light source in proximity to the entrance face, so that light emitted from the light source passes through the device along the optical path and transilluminates the patterning element, thereby generating patterned light.

17. The method according to claim 16 , wherein fixing the patterning element comprises fixing a first spacer between the first plate and the patterning element, and wherein fixing the light source comprises fixing a second spacer between the second plate and a substrate on which the light source is mounted.

Assignees

• Apple Inc

Inventors

• Kriman Moshe
• Magen Adar

Classifications

• G02B19/0028

  refractive and reflective surfaces, e.g. non-imaging catadioptric systems · CPC title

• G03B21/2066 Primary

  Reflectors in illumination beam (in projection beam G03B21/28) · CPC title

• G02B3/0068

  arranged in a single integral body or plate, e.g. laminates or hybrid structures with other optical elements (G02B5/1885, G02B17/002, G02B30/27 take precedence) · CPC title

• G02B27/425

  in illumination systems (mask illumination systems in photolithographic systems G03F7/70158) · CPC title

• G03B21/2033

  LED or laser light sources · CPC title