2-D Planar VCSEL Source for 3-D Imaging

• US 20150260830A1
• Filed: 06/12/2014
• Published: 09/17/2015
• Est. Priority Date: 07/12/2013
• Status: Abandoned Application

• Current Assignee: Princeton Optronics Inc (Ams-Osram AG)
• Original Assignee: Princeton Optronics Inc (Ams-Osram AG)
• Inventors: Ghosh, Chuni Lal, Seurin, Jean Francois, Watkins, Laurence S
• Application Number:
  US14/303,161
• Publication Number:
  US 20150260830A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 17/894 3D imaging with simultaneous measurement of time-of-flight at a 2D array of receiver pixels, e.g. time-of-flight cameras or flash lidar
• CPC Class Codes: G01S 7/4815 using multiple transmitters
• CPC Class Codes: G01S 7/4816 of receivers alone
• CPC Class Codes: G01S 7/484 Transmitters
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/73 Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
• 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 5/02325 Mechanically integrated components on mount members or optical micro-benches
• CPC Class Codes: H01S 5/423 having a vertical cavity

Abstract

An apparatus and a method are provided for 3-D proximity sensing, imaging and scanning using a 2-D planar VCSEL array source using reflected radiation from an object being detected. An important aspect of the apparatus is a compact high power optical source and in particular, an optical source comprising a plurality of VCSELs to illuminate the object. VCSELs in the optical source are configured in different 2-D planar arrangements, such that the optical source may be used in many different modes to adapt to different sensing, imaging and scanning requirement suited for different environments including one where shape, size and illumination mode require to be altered dynamically. When used in different modes of operation the apparatus provides a comprehensive set of measured distance and intensity profile of the object to compute a 3-D image.

Claims

1. A proximity sensing apparatus comprising:

an optical source including a plurality of VCSELs configured in a 2-D spatial arrangement, such that one or more object located within a physical space is illuminated completely or partially, by an incident radiation beam from a pre-determined fixed angle;

a radiation detection apparatus co-located with the optical source in at least one plane, and separated in one orthogonal plane in the physical space, wherein the radiation detection apparatus is disposed at said pre-determined angle with respect to the one or more object, said radiation detection apparatus generates one or more electrical signal proportional to reflected radiation received form the one or more object; and

an electronic instrument including, a programmable current driver to operate said optical source, a data storage device to store the one or more electrical signals generated in response to the reflected light received by the radiation detection apparatus, and a processor, wherein the processor applies one or more signal processing operation to the one or more electrical signals to determine distance corresponding the one or more object.

2. The proximity sensing apparatus as in claim 1 wherein the plurality of VCSELs have a planar structure that is one selected from the group consisting of two-reflector device, extended cavity three-reflector device and extended cavity external three-reflector device.

3. The proximity sensing apparatus as in claim 1, wherein the plurality of VCSELs is monolithically integrated or assembled on a common foreign substrate, and wherein each VCSEL is individually addressable.

4. The proximity sensing apparatus as in claim 1, wherein the 2-D spatial arrangement of the plurality of VCSELs is one selected from a group consisting of a group, cluster, array and a combination thereof, that is individually addressable or operated collectively.

5. The proximity sensing apparatus as in claim 1, wherein the optical source further includes additional plurality of VCSELs arranged in one or more additional 2-D spatial arrangement that is one selected from a group consisting of a group, cluster, array and a combination thereof, that is individually addressable or operated collectively.

6. The proximity sensing apparatus as in claim 1 further including additional one or more optical components placed at a pre-determined distance from the optical source to further collimate collective radiation emitted from the plurality of VCSELs, or radiation emitted from each one of the plurality of VCSEL, wherein the one or more optical components is one selected from the group consisting of microlens, array of microlens, lens and a pre-determined combination thereof.

7. The proximity sensing apparatus as in claim 1 wherein the current driver is configured to drive the plurality of VCSELs using a continuous drive current to emit the incident radiation beam collectively, such that distance of said one or more object from the optical source is computed by comparing intensities of reflected and the incident radiation.

8. The proximity sensing apparatus as in claim 1 wherein:

the current driver is configured to drive the plurality of VCSELs using pulses of drive current so as to emit pulses of the incident radiation beam; and

the radiation detection apparatus includes a plurality of photodetectors having a rise and a fall time substantially matched with a rise and a fall time of pulses of the incident radiation beam, such that distance of the one or more object from the optical source is determined by measuring a time of flight between the pulse of the incident radiation beam, and corresponding reflected radiation pulse received from the one or more object, said respective time of flight is measured synchronized with the pulses of drive current.

9. The proximity sensing apparatus as in claim 8 further measuring intensity and pulse shape of the corresponding reflected radiation pulses received at the radiation detection apparatus to determine an intensity profile for computing an image of the one or more object.

10. The proximity sensing apparatus as in claim 1, wherein the radiation detection apparatus is one selected from a group consisting of an analog camera, a digital camera, a charge coupled detector, a photodetector, and an array of photodetectors.

11. The proximity sensing apparatus as in claim 1 further including an optical filter proximal to the light detection apparatus, wherein the pass band of said optical filter substantially matches the emission wavelength of the plurality of VCSELs.

12. An imaging apparatus comprising:

an optical source including a 2-D spatial arrangement of a plurality of VCSELs;

a radiation detection apparatus co-located with the optical source in at least one plane, and separated in one orthogonal plane in the physical space; and

an electronic instrument including, a programmable current driver, a data storage device and a processor, wherein

the programmable current driver operates a different section of the 2-D spatial arrangement of the plurality of VCSELs to generate multiple incident radiation beams in a pre-determined sequence such that a corresponding different section of one or more object is sequentially illuminated from a pre-determined fixed angle,

the radiation detection apparatus generates one or more electrical signal proportional to reflected radiation received sequentially form the one or more object at said pre-determined angle, and

the processor applies one or more signal processing operation to the one or more electrical signals in synchronization with the pre-determined sequence of the incident radiation beams, such that a time of flight and an intensity profile corresponding to different sections of the one or more object is determined to compute a distance and an image of the one or more object.

13. The imaging apparatus as in claim 12 wherein the plurality of VCSELs have a planar structure that is one selected from the group consisting of two-reflector device, extended cavity three-reflector device and extended cavity external three-reflector device.

14. The imaging apparatus as in claim 12, wherein the plurality of VCSELs is monolithically integrated or assembled on a common foreign substrate, and wherein each VCSEL is individually addressable.

15. The imaging apparatus as in claim 12, wherein the 2-D spatial arrangement is one selected from a group consisting of a group, cluster, array and a combination thereof, that is individually addressable or operated collectively.

16. The imaging apparatus as in claim 12, wherein the optical source further includes additional plurality of VCSELs arranged in one or more additional 2-D spatial arrangement that is one selected from a group consisting of a group, cluster, array and a combination thereof, that is individually addressable or operated collectively.

17. The imaging apparatus as in claim 12 further including additional one or more optical components placed at a pre-determined distance between the illumination source and the object to further collimate light emitted from each emitter, or the collective emission from the plurality of emitters, wherein the one or more optical components is one selected from the group consisting of microlens, array of microlens, lens and a pre-determined combination thereof.

18. The imaging apparatus as in claim 12 wherein:

the current driver is configured to drive the plurality of VCSELs using pulses of drive current so as to emit pulses of the incident radiation beam; and

the radiation detection apparatus includes a plurality of photodetectors having a rise and a fall time substantially matched with a rise and a fall time of pulses of the incident radiation beam, such that distance of the one or more object from the optical source is determined by measuring a time of flight between the pulse of the incident radiation beam, and corresponding reflected radiation pulse received from the one or more object, said respective time of flight is measured synchronized with the pulses of drive current.

19. The imaging apparatus as in claim 12, wherein the radiation detection apparatus is one selected from a group consisting of an analog camera, a digital camera, a charge coupled detector, a photodetector, and an array of photodetectors.

20. The imaging apparatus as in claim 12 further including an optical filter proximal to the light detection apparatus, wherein the pass band of said optical filter substantially matches with the emission wavelength of the plurality of emitters.

21. The imaging apparatus as in claim 12 wherein the radiation detection apparatus comprises:

a plurality of photodetectors arranged in a pre-determined 2-D spatial arrangement, and

a plurality of microlens positioned between the one or more object and the plurality of photodetectors, wherein the each microlens is registered with one or more of the plurality of photdetectors, such that each microlens focuses reflected light received in proportion to the distance of the corresponding different sections of the one or more object on to the respective photodetector.

22. The imaging apparatus of claim 21, wherein the pre-determined 2-D spatial arrangement of the plurality of photodetectors is one selected from a group consisting of a group, cluster, array, and a combination thereof.

23. The imaging apparatus of claim 21, wherein the pre-determined 2-D spatial arrangement of the plurality of photodetectors and the plurality of microlens is substantially similar.

24. The imaging apparatus of claim 21, wherein the 2-D spatial arrangement of the plurality of VCSELs and the 2-D spatial arrangement of the plurality of photodetectors is substantially similar.

25. The imaging apparatus of claim 21, wherein the plurality of photodetectors are equivalent of individual pixels of a digital camera.