Optical pattern projection

• US 20130120841A1
• Filed: 01/06/2013
• Published: 05/16/2013
• Est. Priority Date: 01/21/2008
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: PrimeSense Ltd (Apple Inc.)
• Inventors: Shpunt, Alexander, Pesach, Benny
• Granted Patent: US 9,239,467 B2
• Time in Patent Office: Days
• US Class Current: 359/558
• 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: G02B 27/0037 with diffracting elements G02B27/0056 takes precedence; holographic optical elements G02B5/32; zone systems G02B5/1876
• CPC Class Codes: G02B 27/0944 Diffractive optical elements, e.g. gratings, holograms gratings per se G02B5/18; holograms used as optical elements per se G02B5/32
• CPC Class Codes: G02B 27/1086 operating by diffraction only
• CPC Class Codes: G02B 27/42 Diffraction optics , i.e. systems including a diffractive element being designed for providing a diffractive effectG02B27/60 takes precedence
• CPC Class Codes: G02B 27/4205 having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant
• CPC Class Codes: G02B 27/4244 in wavelength selecting devices spectrometry G01J
• CPC Class Codes: G02B 27/425 in illumination systems mask illumination systems in photolithographic systems G03F7/70158
• CPC Class Codes: G02B 27/4272 having plural diffractive elements positioned sequentially along the optical path
• CPC Class Codes: G02B 27/4277 being separated by an air space
• CPC Class Codes: G02B 5/1819 Plural gratings positioned on the same surface, e.g. array of gratings plural diffractive elements positioned sequentially along the optical path G02B27/4272
• CPC Class Codes: G03B 35/00 Stereoscopic photography
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light
• CPC Class Codes: H04N 13/254 in combination with electromagnetic radiation sources for illuminating objects
• CPC Class Codes: H04N 13/271 wherein the generated image signals comprise depth maps or disparity maps

Abstract

Optical apparatus includes first and second diffractive optical elements (DOEs) arranged in series to diffract an input beam of radiation. The first DOE is configured to apply to the input beam a pattern with a specified divergence angle, while the second DOE is configured to split the input beam into a matrix of output beams with a specified fan-out angle. The divergence and fan-out angles are chosen so as to project the radiation onto a region in space in multiple adjacent instances of the pattern.

Claims

1. Optical apparatus, comprising first and second diffractive optical elements (DOEs) arranged in series to diffract an input beam of radiation,

wherein the first DOE is configured to apply to the input beam a pattern with a specified divergence angle, while the second DOE is configured to split the input beam into a matrix of output beams with a specified fan-out angle, and

wherein the divergence and fan-out angles are chosen so as to project the radiation onto a region in space in multiple adjacent instances of the pattern, which tile the region,

wherein the divergence angle of each instance of the pattern is 1β

_Tile, and the fan-out angle between the adjacent instances is β

_FO, and wherein the divergence and fan-out angles are chosen so that sin(β

_FO)=2 sin(β

_Tile).

2. The apparatus according to claim 1, wherein the first and second DOEs are configured so that the multiple adjacent instances of the pattern tile the region irrespective of a wavelength of the input beam.

3. The apparatus according to claim 1, wherein each of the multiple adjacent instances comprises multiple diffraction orders, including respective extreme orders, and wherein the extreme orders of neighboring instances are mutually adjacent in a spatial frequency space.

4. The apparatus according to claim 1, wherein the second DOE is configured to distribute an energy of the input beam among the output beams in accordance with a predefined non-uniform distribution.

5. The apparatus according to claim 1, wherein a diffraction pattern of the apparatus includes a zero-order component, and wherein the first and second DOEs are configured to diffract the input beam so that the zero-order component contains no more than 1% of an energy of the input beam.

6. The apparatus according to claim 1, wherein the matrix of the output beams comprises at least a 3×

3 matrix.

8. The apparatus according to claim 1, wherein a diffraction pattern of the apparatus includes a zero-order component, and wherein the first and second DOEs are configured to diffract the input beam so that the zero-order component contains no more than 1% of an energy of the input beam.

7. Optical apparatus, comprising first and second diffractive optical elements (DOEs) arranged in series to diffract an input beam of radiation,

wherein the first DOE is configured to apply to the input beam a pattern with a specified divergence angle, while the second DOE is configured to split the input beam into a matrix of output beams with a specified fan-out angle, and

wherein the divergence and fan-out angles are chosen so as to project the radiation onto a region in space in multiple adjacent instances of the pattern, which tile the region,

wherein each of the multiple adjacent instances comprises multiple diffraction orders, including respective extreme orders, and wherein the extreme orders of neighboring instances are mutually adjacent in a spatial frequency space.

9. Mapping apparatus, comprising:

a projection subassembly, comprising;

a radiation source, which is configured to generate an input beam of radiation; and

first and second diffractive optical elements (DOEs) arranged in series to diffract the input beam, wherein the first DOE is configured to apply to the input beam a pattern with a specified divergence angle, while the second DOE is configured to split the input beam into a matrix of output beams with a specified fan-out angle, so as to project the radiation onto a region in space,

wherein the divergence and fan-out angles are chosen so that the radiation is projected into multiple adjacent instances of the pattern, which tile the region, and wherein the divergence angle of each instance of the pattern is 2β

_Tile, and the fan-out angle between the adjacent instances is β

_FO, and wherein the divergence and fan-out angles are chosen so that sin (β

_FO)=2 sin (β

_Tile);

an image capture subassembly, which is configured to capture an image of the pattern appearing on an object in the region; and

a processor, which is configured to process the image so as to produce a three-dimensional (3D) map of the object.

10. The apparatus according to claim 9, wherein the first and second DOEs are configured so that the multiple adjacent instances of the pattern tile the region irrespective of a wavelength of the input beam.

11. The apparatus according to claim 9, wherein each of the multiple adjacent instances comprises multiple diffraction orders, including respective extreme orders, and wherein the extreme orders of neighboring instances are mutually adjacent in a spatial frequency space.

12. The apparatus according to claim 9, wherein the second DOE is configured to distribute an energy of the input beam among the output beams in accordance with a predefined non-uniform distribution.

13. The apparatus according to claim 9, wherein a diffraction pattern of the projection subassembly includes a zero-order component, and wherein the first and second DOEs are configured to diffract the input beam so that the zero-order component contains no more than 5% of an energy of the input beam.

14. The apparatus according to claim 9, wherein the matrix of the output beams comprises at least a 3×

3 matrix.

15. Mapping apparatus, comprising:

a projection subassembly, comprising;

a radiation source, which is configured to generate an input beam of radiation; and

first and second diffractive optical elements (DOEs) arranged in series to diffract the input beam, wherein the first DOE is configured to apply to the input beam a pattern with a specified divergence angle, while the second DOE is configured to split the input beam into a matrix of output beams with a specified fan-out angle, so as to project the radiation onto a region in space,

wherein the divergence and fan-out angles are chosen so that the radiation is projected into multiple adjacent instances of the pattern, which tile the region, and wherein each of the multiple adjacent instances comprises multiple diffraction orders, including respective extreme orders, and wherein the extreme orders of neighboring instances are mutually adjacent in a spatial frequency space;

an image capture subassembly, which is configured to capture an image of the pattern appearing on an object in the region; and

a processor, which is configured to process the image so as to produce a three-dimensional (3D) map of the object.

16. The apparatus according to claim 15, wherein a diffraction pattern of the projection subassembly includes a zero-order component, and wherein the first and second DOEs are configured to diffract the input beam so that the zero-order component contains no more than 5% of an energy of the input beam.

17. A method for projection, comprising:

directing an input beam of radiation to pass in series through first and second diffractive optical elements (DOEs),

wherein the first DOE is configured to apply to the input beam a pattern with a specified divergence angle, while the second DOE is configured to split the input beam into a matrix of output beams with a specified fan-out angle, and

wherein the divergence and fan-out angles are chosen so as to project the radiation onto a region in space in multiple adjacent instances of the pattern, which tile the region, and

wherein the divergence angle of each instance of the pattern is 2β

_Tile, and the fan-out angle between the adjacent instances is β

_FO, and wherein the divergence and fan-out angles are chosen so that sin(β

_FO)=2 sin(β

_Tile).

18. The method according to claim 17, wherein directing the input beam comprises arranging the first and second DOEs so that the multiple adjacent instances of the pattern tile the region irrespective of a wavelength of the input beam.

19. The method according to claim 17, wherein each of the multiple adjacent instances comprises multiple diffraction orders, including respective extreme orders, and wherein the extreme orders of neighboring instances are mutually adjacent in a spatial frequency space.

20. The method according to claim 17, wherein the second DOE is configured to distribute an energy of the input beam among the output beams in accordance with a predefined non-uniform distribution.

21. The method according to claim 17, wherein directing the input beam to pass through the first and second DOEs comprises generating a diffraction pattern that includes a zero-order component, and wherein the first and second DOEs are configured to diffract the input beam so that the zero-order component contains no more than 5% of an energy of the input beam.

22. The method according to claim 17, wherein the matrix of the output beams comprises at least a 3×

3 matrix.

23. The method according to claim 17, and comprising capturing an image of the pattern appearing on an object in the region, and processing the image so as to produce a three-dimensional (3D) map of the object.

24. A method for projection, comprising:

directing an input beam of radiation to pass in series through first and second diffractive optical elements (DOEs),

wherein the first DOE is configured to apply to the input beam a pattern with a specified divergence angle, while the second DOE is configured to split the input beam into a matrix of output beams with a specified fan-out angle, and

wherein the divergence and fan-out angles are chosen so as to project the radiation onto a region in space in multiple adjacent instances of the pattern, which tile the region, and

wherein each of the multiple adjacent instances comprises multiple diffraction orders, including respective extreme orders, and wherein the extreme orders of neighboring instances are mutually adjacent in a spatial frequency space.

25. The method according to claim 24, wherein directing the input beam to pass through the first and second DOEs comprises generating a diffraction pattern that includes a zero-order component, and wherein the first and second DOEs are configured to diffract the input beam so that the zero-order component contains no more than 5% of an energy of the input beam.

26. The method according to claim 24, and comprising capturing an image of the pattern appearing on an object in the region, and processing the image so as to produce a three-dimensional (3D) map of the object.