Illumination modules that emit structured light

Abstract

A depth camera includes an illumination module and an image detector module. The illumination module outputs structured light that illuminates a capture area. The image detector module captures an image of the structured light as reflected from object(s) within the capture area. The illumination module includes a VCSEL array and optical element(s), such as projection optics, an MLA or DOE, or combinations thereof. Projection optics receive a light pattern emitted by the VCSEL array and project the light pattern. An optical element, downstream from the projection optics, can cause a total number of features included in the structured light to be greater than the number of features included in the light pattern projected by the projection optics. In an embodiment, a pitch of an MLA is offset relative to a pitch of the VCSEL array. Various structures can include alignment elements to aid manufacture of the illumination module.

What is claimed is: 
     
         1 . A depth camera system, comprising:
 an illumination module configured to output structured light that illuminates a capture area; and   an image detector module configured to output an image of the structured light as reflected from one or more objects within the capture area;   the illumination module including
 a VCSEL array comprising a plurality of vertical cavity surface emitting lasers (VCSELs) having a first pitch; 
 a micro-lens array (MLA) comprising a plurality of lenslets having a second pitch that is offset relative to the first pitch of VCSEL array, which causes light beams received by the MLA, from the VCSEL array, to converge; and 
 a diffractive optical element (DOE) configured to receive converged light beams from the MLA and output the structured light that illuminates the capture area. 
   
     
     
         2 . The depth camera system of  claim 1 , wherein the second pitch is less than the first pitch. 
     
     
         3 . The depth camera system of  claim 1 , wherein the MLA is configured to cause light beams, received by the MLA from the VCSEL array, to converge to a single pupil at which is located the DOE. 
     
     
         4 . The depth camera system of  claim 1 , wherein:
 a light pattern output by the MLA includes a number of features; and   the DOE is configured to cause a total number of features included in the structured light output by the illumination module to be an integer multiple of the number of features included in the light pattern output by the MLA.   
     
     
         5 . The depth camera system of  claim 4 , wherein the DOE is configured to cause the total number of features included in the structured light output by the illumination module to be twice or thrice the number of features included in the light pattern output by the MLA. 
     
     
         6 . The depth camera system of  claim 1 , wherein:
 the VCSEL array is formed on a semiconductor substrate that includes first alignment elements; and   the MLA includes second alignment elements that align with the first alignment elements.   
     
     
         7 . The depth camera system of  claim 1 , further comprising:
 one or more processors configured to produce a depth image in dependence on the image captured by the image detector module;   wherein the one or more processors is/are also configured to update an application based on the depth image.   
     
     
         8 . A method, comprising:
 emitting a separate beam of light from each of a plurality of vertical cavity surface emitting laser (VCSELs) of a VCSEL array to thereby collectively emit a light pattern;   receiving the beams of light emitted by the VCSELs of the VCSEL array, at a micro-lens array (MLA) comprising a plurality of lenslets having a second pitch that is offset relative to the first pitch of VCSEL array, and using the MLA to cause the beams of light received by the MLA, from the VCSEL array, to converge to a single pupil;   receiving the converged beams from the MLA, at a diffractive optical element (DOE) that is positioned adjacent MLA at the single pupil, and using the DOE to diverge the beams to produce a projected light pattern;   illuminating a capture area with structured light that is created at least in part based on the projected light pattern produced using the DOE; and   capturing an image of the structured light as reflected from one or more objects within the capture area.   
     
     
         9 . The method of  claim 8 , wherein the second pitch is less than the first pitch. 
     
     
         10 . The method of  claim 8 , wherein a light pattern output by the MLA includes a number of features; and further comprising using the DOE to cause a total number of features included in the structured light to be an integer multiple of the number of features included in the light pattern output by the MLA. 
     
     
         11 . The method of  claim 8 , wherein a light pattern output by the MLA includes a number of features; and further comprising using the DOE to cause a total number of features included in the structured light to be twice the number of features included in the light pattern output by the MLA. 
     
     
         12 . The method of  claim 8 , wherein a light pattern output by the MLA includes a number of features; and further comprising using the DOE to cause a total number of features included in the structured light to be thrice the number of features included in the light pattern output by the MLA. 
     
     
         13 . The method of  claim 8 , wherein:
 the VCSEL array is formed on a semiconductor substrate that includes first alignment elements; and   the MLA includes second alignment elements that align with the first alignment elements; and   further comprising using the first and second alignment elements to align the MLA with the VCSEL array.   
     
     
         14 . The method of  claim 8 , further comprising producing a depth image in dependence on the captured image. 
     
     
         15 . The method of  claim 14 , further comprising updating an application based on the depth image. 
     
     
         16 . A depth camera system, comprising:
 an illumination module configured to output structured light that illuminates a capture area; and   an image detector module configured to capture an image of the structured light as reflected from one or more objects within the capture area;   the illumination module including
 a VCSEL array comprising a plurality of vertical cavity surface emitting lasers (VCSELs), wherein each of the VCSELs is configured to emit a separate beam of light; 
 a first diffractive optical element (DOE) configured to collimate each beam of light output by each of the plurality of VCSELs of the VCSEL array; and 
 a second DOE configured to receive the collimated beams produced by the first DOE and output the structured light. 
   
     
     
         17 . The depth camera system of  claim 16 , wherein:
 a light pattern output by the first DOE includes a number of features; and   the second DOE is configured to cause a total number of features included in the structured light output by the illumination module to be an integer multiple of the number of features included in the light pattern output by the first DOE.   
     
     
         18 . The depth camera system of  claim 17 , wherein the second DOE is configured to cause the total number of features included in the structured light output by the illumination module to be twice or thrice the number of features included in the light pattern output by the first DOE. 
     
     
         19 . The depth camera system of  claim 16 , further comprising:
 one or more processors configured to produce a depth image in dependence on the image captured by the image detector module.   
     
     
         20 . The depth camera system of  claim 19 , wherein the one or more processors is/are also configured to update an application based on the depth image.