Programmable pattern optical projector for depth detection

{
  "publication_number": "US10509128B1",
  "country": "US",
  "kind": "B1",
  "title": "Programmable pattern optical projector for depth detection",
  "abstract": "In an embodiment, an optical projector is provided with a laser array. Each laser is either collimated or focused to a fixed distance. At least one multiple beam grating (MBG) is placed in front of the laser array. The light pattern from the laser array is duplicated by the MBG, and cast on an object to be measured. The pattern on the object is changed by rotating the MBG. As a result, the number of patterns of structured dots that can be projected on the object is nearly unlimited. The optical projector can be used to provide depth perception to motion detection systems, to vehicle self-driving systems, and for many other uses.",
  "claims": [
    "1. An apparatus comprising: an array of lasers mounted on a substrate that produce a plurality of laser beams; an array of lenses mounted in front of the array of lasers, each lens in the array of lenses being shaped to modify one of the plurality of laser beams to collimate the laser beam or substantially collimate the laser beam by focusing the laser beam at a fixed distance, producing a laser beam pattern; a first multiple beam grating mounted to intercept the laser beam pattern to both duplicate the laser beam pattern to produce duplicated laser beam patterns and direct the duplicated laser beam patterns onto an object; and a rotational element coupled to the first multiple beam grating to rotate the first multiple beam grating to produce a variety of different laser beam patterns.",
    "2. The apparatus of claim 1 wherein the first multiple beam grating is a disc, and the rotating element includes an axle connected to the disc.",
    "3. The apparatus of claim 1 further comprising a second multiple beam grating mounted between the first multiple beam grating and the array of lenses.",
    "4. The apparatus of claim 3 wherein the first and second multiple beam gratings are one dimensional patterned gratings.",
    "5. The apparatus of claim 1 wherein the array of lasers comprises an array of separate laser chips mounted on the substrate.",
    "6. The apparatus of claim 1 further comprising control circuitry connected to the array of lasers to independently excite different lasers in the array of lasers.",
    "7. The apparatus of claim 1 wherein the array of lenses comprises a lenslet array.",
    "8. The apparatus of claim 1 wherein the array of lasers comprises an array of edge emitting lasers.",
    "9. The apparatus of claim 1 wherein the array of lasers comprises an array of vertical cavity surface emitting lasers (VCSEL).",
    "10. The apparatus of claim 1 further comprising a second multiple beam grating mounted between the first multiple beam grating and the array of lenses; and wherein the rotational element is connected to both the first and second multiple beam gratings to rotate both.",
    "11. An electronic device comprising: an optical projector module including: an array of lasers mounted on a substrate that produce a plurality of laser beams; an array of lenses mounted in front of the array of lasers, each lens in the array of lenses being shaped to modify one of the plurality of laser beams to collimate the laser beam or substantially collimate the laser beam by focusing the laser beam at a fixed distance, producing a laser beam pattern; a first multiple beam grating mounted to intercept the laser beam pattern to both duplicate the laser beam pattern to produce duplicated laser beam patterns and direct the duplicated laser beam patterns onto an object a rotational element coupled to the first multiple beam grating to rotate the first multiple beam grating to produce a variety of different laser beam patterns; and a photodetector; a microprocessor; a memory containing non-transitory computer readable media with instructions for: recording a first position of each of the laser beams in the laser beam patterns where they would be reflected off a flat surface and detected by the photodetector; recording a second position of each of the laser beams in the laser beam patterns as detected by the photodetector after reflection off of a non-flat object to be measured; determining a difference between the first and second positions for each of the laser beams of the laser beam patterns; and generating a map of the depth of the non-flat object at different points based on the difference between the first and second positions for the laser beams of the laser beam patterns.",
    "12. The electronic device of claim 11 wherein the array of lasers is an irregular array mounted on a PC board.",
    "13. A method comprising: producing a plurality of laser beams from an array of lasers; modifying the plurality of laser beams with an array of lenses to collimate the laser beams or substantially collimate the laser beams by focusing the laser beams at a fixed distance, producing a laser beam pattern; duplicating the laser beam pattern and directing the laser beam pattern onto an object with a first multiple beam grating; and rotating the first multiple beam grating to produce a variety of different laser beam patterns.",
    "14. The method of claim 13 further comprising multiplying the laser beams with a second multiple beam grating mounted between the first multiple beam grating and the array of lenses.",
    "15. The method of claim 13 further comprising independently exciting different lasers in the array of lasers.",
    "16. The method of claim 15 wherein the different lasers excited at one time form an irregular pattern.",
    "17. The method of claim 13 further comprising: recording a first position of each of the laser beams in the laser beam pattern where they would be reflected off a flat surface and detected by a photodetector; recording a second position of each of the laser beams in the laser beam pattern as detected by the photodetector after reflection off of a non-flat object to be measured; determining a difference between the first and second positions for each of the laser beams of the laser beam pattern; and generating a map of the depth of the non-flat object at different points based on the difference between the first and second positions for the laser beams of the laser beam pattern.",
    "18. The method of claim 13 wherein the array of lasers is an irregular array mounted on a PC board.",
    "19. The method of claim 13 wherein each laser is an edge emitting laser.",
    "20. The method of claim 13 wherein each laser is a vertical cavity surface emitting laser (VCSEL)."
  ],
  "description_excerpt": "The present invention relates to optical projection using diffraction for uses such as three dimensional (3D) surface measurements for facial recognition, motion detection, or other purposes.\n\nOptical projection of a pattern is used in applications such as 3D surface measurements. The positions of a pattern of dots caused by beams projected onto a flat surface can be determined. When the same pattern of dots is projected on a 3D surface to be measured, the positions of the dots will deviate from their designed positions as a result of the different intersection height on the 3D surface. These deviations can be measured and correlated to the different distances, or depth, of the 3D surface, and a 3D image can be generated. Such a system can also be used for motion detection and other uses.\n\nFIG. 1 shows an example application of a miniaturized optical projector for depth measurements. A smartphone 10 includes a display 12, a camera 14 and an internal processor and other electronics. Display 12 can be used for presenting information to a user, and also functions as a touch screen for inputting information. An optical projector/ detector module 16 is provided. Projector/ detector module 16 projects an IR image which diverges as shown by arrows 18. The IR image is projected onto a user's face 20 as a series of dots 22. A detector in optical projector/ detector module 16 then detects the dots 22, and from their relative positions, can determine the depth of the various parts of the user's face 20. By combining this with traditional two dimensional facial recognition, a user's face can be detected with great accuracy.",
  "cpc": [
    "G01S 17/89",
    "G01B 11/2513",
    "G01S 17/42",
    "G01S 7/4815",
    "G01S 7/484",
    "H01S 5/02253",
    "H01S 5/02288",
    "H01S 5/042",
    "H01S 5/4012",
    "H01S 5/4031",
    "H01S 5/423"
  ],
  "ipc": [
    "G01C 3/08",
    "G01S 17/42",
    "G01S 17/89",
    "G01S 7/481",
    "G01S 7/484",
    "H01S 5/022",
    "H01S 5/042",
    "H01S 5/40",
    "H01S 5/42"
  ],
  "assignees": [
    "K Laser Technology Inc"
  ],
  "inventors": [
    "Wai-Hon Lee"
  ],
  "filing_date": "2019-04-12",
  "publication_date": "2019-12-17",
  "grant_date": "2019-12-17",
  "priority_date": "2019-04-12",
  "application_number": "US-201916383457-A",
  "family_id": "68841352",
  "cited_by_count": 8,
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    "US20100007771A1",
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  ]
}