Projectors of Structured Light

• US 20130038881A1
• Filed: 08/06/2012
• Published: 02/14/2013
• Est. Priority Date: 08/09/2011
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: PrimeSense Ltd (Apple Inc.)
• Inventors: Pesach, Benny, Mor, Zafrir, Yalov, Shimon, Shpunt, Alexander
• Granted Patent: US 8,749,796 B2
• Time in Patent Office: Days
• US Class Current: 356/610
• CPC Class Codes: G01B 11/25 by projecting a pattern, e.g. one or more lines, moiré fringes on the object G01B11/255 takes precedence ; image analysis for depth or shape recovery G06T7/50
• CPC Class Codes: G01B 11/2513 with several lines being projected in more than one direction, e.g. grids, patterns
• CPC Class Codes: G02B 27/106 for splitting or combining a plurality of identical beams or images, e.g. image replication
• CPC Class Codes: G02B 27/1086 operating by diffraction only
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01S 5/005 Optical components external to the laser cavity, specially adapted therefor, e.g. for homogenisation or merging of the beams or for manipulating laser pulses, e.g. pulse shaping H01S5/026, H01S5/18388 take precedence
• CPC Class Codes: H01S 5/423 having a vertical cavity

Abstract

Optical apparatus includes a beam source, which is configured to generate an optical beam having a pattern imposed thereon. A projection lens is configured to receive and project the optical beam so as to cast the pattern onto a first area in space having a first angular extent. A field multiplier is interposed between the projection lens and the first area and is configured to expand the projected optical beam so as to cast the pattern onto a second area in space having a second angular extent that is at least 50% greater than the first angular extent.

Claims

1. Optical apparatus, comprising:

a beam source, which is configured to generate an optical beam having a pattern imposed thereon;

a projection lens, which is configured to receive and project the optical beam so as to cast the pattern onto a first area in space having a first angular extent; and

a field multiplier, which is interposed between the projection lens and the first area and is configured to expand the projected optical beam so as to cast the pattern onto a second area in space having a second angular extent that is at least 50% greater than the first angular extent.

2. The apparatus according to claim 1, wherein the second angular extent is at least twice the first angular extent.

3. The apparatus according to claim 1, and comprising a reflective surface interposed so as to fold the projected optical beam between the projection lens and the field multiplier.

4. The apparatus according to claim 1, wherein the field multiplier comprises a diffractive optical element (DOE).

5. The apparatus according to claim 4, wherein the DOE is configured to expand the projected optical beam by producing multiple, mutually-adjacent tiles on the second area, each tile containing a respective replica of the pattern.

6. The apparatus according to claim 5, wherein the DOE is configured to generate a two-dimensional array of the tiles.

7. The apparatus according to claim 6, wherein the tiles have a pitch, and wherein at least some of the tiles are offset transversely relative to neighboring tiles by an offset that is a fraction of the pitch.

8. The apparatus according to claim 1, wherein the field multiplier comprises a prism.

9. The apparatus according to claim 8, wherein the prism has an edge and is positioned so that the optical beam projected by the projection lens is incident on the edge.

10. The apparatus according to claim 9, wherein the prism has a triangular profile with a vertex angle that is greater than 90°

at the edge upon which the projected optical beam is incident.

11. The apparatus according to claim 8, wherein the field multiplier comprises first and second prisms, having respective first and second edges and having respective first and second bases opposite the first and second edges, wherein the first and second bases are joined together while the first and prisms are rotated so that the first and second edges opposite the bases are mutually perpendicular.

12. The apparatus according to claim 8, wherein the prism has a pyramidal shape with an apex and is positioned so that the optical beam projected by the projection lens is incident on the apex.

13. The apparatus according to claim 8, wherein the prism comprises an internal reflective surface configured to fold the projected optical beam.

14. The apparatus according to claim 1, wherein the beam source comprises a light source, which emits the optical beam, and a patterning element, which is interposed in the optical beam emitted by the light source.

15. The apparatus according to claim 1, wherein the beam source comprises a monolithic array of light-emitting elements, arranged on a semiconductor substrate in a two-dimensional pattern corresponding to the pattern imposed on the optical beam.

16. An optoelectronic device, comprising:

a semiconductor substrate; and

a monolithic array of light-emitting elements, arranged on the substrate in a two-dimensional pattern that is not a regular lattice.

17. The device according to claim 16, wherein the light-emitting elements comprise vertical-cavity surface-emitting laser (VCSEL) diodes.

18. The device according to claim 16, wherein the two-dimensional pattern of the light-emitting elements is an uncorrelated pattern.

19. The device according to claim 16, wherein the light-emitting elements comprise first and second sets of the light-emitting elements, wherein the first and second sets are interleaved on the substrate in respective first and second patterns, and

wherein the device comprises first and second conductors, which are respectively connected to separately drive the first and second sets of the light-emitting elements so that the device selectably emits light in either or both of the first and second patterns.

20. The device according to claim 19, and

comprising:

projection optics, which are configured to project the light emitted by the light emitting elements onto an object; and

an imaging device, which is configured to capture images of the object in a low-resolution mode while only the first set of the light-emitting elements is driven to emit the light, thereby projecting a low-resolution pattern onto the object, and in a high-resolution mode while both of the first and second sets of the light-emitting elements are driven to emit the light, thereby projecting a high-resolution pattern onto the object.

21. The device according to claim 16, and comprising a projection lens, which is mounted on the semiconductor substrate and is configured to collect and focus light emitted by the light-emitting elements so as to project an optical beam containing a light pattern corresponding to the two-dimensional pattern of the light-emitting elements on the substrate.

22. The device according to claim 21, and comprising a diffractive optical element (DOE), which is mounted on the substrate and is configured to expand the projected optical beam by producing multiple, mutually-adjacent replicas of the pattern.

23. The device according to claim 22, wherein the projection lens and the DOE are formed on opposing sides of a single optical substrate.

24. The device according to claim 16, and comprising a single diffractive optical element (DOE), which is mounted on the semiconductor substrate and is configured to collect and focus light emitted by the light-emitting elements so as to project an optical beam containing a light pattern corresponding to the two-dimensional pattern of the light-emitting elements on the substrate while expanding the projected optical beam by producing multiple, mutually-adjacent replicas of the pattern.

25. A method for pattern projection, comprising:

generating an optical beam having a pattern imposed thereon;

projecting the optical beam using a projection lens so as to cast the pattern onto a first area in space having a first angular extent; and

applying a field multiplier to expand the optical beam projected by the projection lens so as to cast the pattern onto a second area in space having a second angular extent that is at least 50% greater than the first angular extent.

26. The method according to claim 25, wherein the second angular extent is at least twice the first angular extent.

27. The method according to claim 25, and comprising folding the projected optical beam using a reflective surface interposed between the projection lens and the field multiplier.

28. The method according to claim 25, wherein the field multiplier comprises a diffractive optical element (DOE).

29. The method according to claim 28, wherein applying the field multiplier comprises expanding the projected optical beam by producing multiple, mutually-adjacent tiles on the second area, each tile containing a respective replica of the pattern.

30. The method according to claim 25, wherein the field multiplier comprises a prism.

31. The method according to claim 30, wherein applying the field multiplier comprises position an edge of the prism so that the optical beam projected by the projection lens is incident on the edge.

32. The method according to claim 25, wherein generating the optical beam comprises transmitting the optical beam through a patterning element.

33. The method according to claim 25, wherein generating the optical beam comprises driving a monolithic array of light-emitting elements, arranged on a semiconductor substrate in a two-dimensional pattern corresponding to the pattern imposed on the optical beam, to emit the optical beam.

34. A method for producing an optoelectronic device, the method comprising:

providing a semiconductor substrate; and

forming a monolithic array of light-emitting elements on the substrate in a two-dimensional pattern that is not a regular lattice.

35. The method according to claim 34, wherein the light-emitting elements comprise vertical-cavity surface-emitting laser (VCSEL) diodes.

36. The method according to claim 34, wherein the two-dimensional pattern of the light-emitting elements is an uncorrelated pattern.

37. The method according to claim 34, wherein forming the monolithic array comprises forming first and second sets of the light-emitting elements, wherein the first and second sets are interleaved on the substrate in respective first and second patterns, and

wherein the method comprises separately driving the first and second sets of the light-emitting elements so that the device selectably emits light in either or both of the first and second patterns.

38. The method according to claim 37, and comprising:

projecting the light emitted by the light emitting elements onto an object;

capturing first images of the object in a low-resolution mode while only the first set of the light-emitting elements is driven to emit the light, thereby projecting a low-resolution pattern onto the object; and

capturing second images in a high-resolution mode while both of the first and second sets of the light-emitting elements are driven to emit the light, thereby projecting a high-resolution pattern onto the object.

39. The method according to claim 34, and comprising mounting a projection lens on the semiconductor substrate so as to collect and focus light emitted by the light-emitting elements, thereby projecting an optical beam containing a light pattern corresponding to the two-dimensional pattern of the light-emitting elements on the substrate.

40. The method according to claim 39, and comprising mounting a diffractive optical element (DOE) on the substrate so as to expand the projected optical beam by producing multiple, mutually-adjacent replicas of the pattern.

41. The method according to claim 40, wherein the projection lens and the DOE are formed on opposing sides of a single optical substrate.

42. The method according to claim 41, and comprising mounting on the substrate a single diffractive optical element (DOE) to collect and focus light emitted by the light-emitting elements so as to project an optical beam containing a light pattern corresponding to the two-dimensional pattern of the light-emitting elements on the substrate while expanding the projected optical beam by producing multiple, mutually-adjacent replicas of the pattern.