Vertical cavity surface emitting laser (VCSEL) based pattern projector
An optoelectronic apparatus is adapted to generate a structured light pattern. The optoelectronic apparatus has: a first array of vertical cavity surface emitting lasers (VCSELs); a first homogenization optics arrangement associated with the first array of VCSELs; a second array of VCSELs; a second homogenization optics arrangement associated with the second array of VCSELs; and a pattern optics arrangement configured to generate a structured light pattern based on a common homogeneous intensity distribution in an intermediate plane. The first homogenization optics arrangement and the second homogenization, each associated with a different one of the first array of VCSELs or the second array of VCSELs, are arranged such that their intensity distributions add up to the common homogeneous top-hat intensity distribution in the intermediate plane.
1 . An optoelectronic apparatus adapted to generate a structured light pattern, the optoelectronic apparatus comprising:
a first array of vertical cavity surface emitting lasers (VCSELs);
a first homogenization optics arrangement associated with the first array of VCSELs;
a second array of VCSELs;
a second homogenization optics arrangement associated with the second array of VCSELs,
wherein the first homogenization optics arrangement and the second homogenization optics arrangement, each associated with a different one of the first array of VCSELs or the second array of VCSELs, are arranged such that their intensity distributions add up to a common homogeneous top-hat intensity distribution in an intermediate plane; and
a pattern optics arrangement positioned downstream from the intermediate plane, the pattern optics arrangement comprising a first microlens array and configured to generate a structured light pattern based on the common homogeneous intensity distribution in the intermediate plane.
2 . The apparatus as claimed in claim 1 , wherein the first homogenization optics arrangement is configured such that a contribution of each individual VCSEL of the first array of VCSELs to an intensity at a surface element of the intermediate plane is less than 10% of an intensity of light emitted by the first array of VCSELs at the surface element.
3 . The apparatus as claimed in claim 2 , wherein the first homogenization optics arrangement is configured to provide a top-hat intensity distribution as the homogeneous intensity distribution in the intermediate plane,
wherein a full width at half maximum (FWHM) diameter of the top-hat intensity distribution is larger than a diameter of the first array of VCSELs.
4 . The apparatus as claimed in claim 1 , wherein the optoelectronic apparatus is configured to generate a dot pattern as the structured light pattern.
5 . The apparatus as claimed in claim 1 , wherein the optoelectronic apparatus is configured to generate a stripe pattern as the structured light pattern.
6 . The apparatus as claimed in claim 1 , wherein the first homogenization optics arrangement comprises a microlens array adapted to provide a homogeneous intensity distribution of light emitted by a plurality of VCSELs of the first array of VCSELs in the intermediate plane.
7 . The apparatus as claimed in claim 6 ,
wherein at least a first microlens of the microlens array is configured to project a first magnified image of an active area of a corresponding first VCSEL of the first array of VCSELs onto the intermediate plane,
wherein at least a second microlens of the microlens array is configured to project a second magnified image of an active area of a corresponding second VCSEL of the first array of VCSELs onto the intermediate plane, and
wherein the first microlens and the second microlens are configured to project the first magnified image and the second magnified image in the intermediate plane so as to provide an aligned superposition of the first magnified image and the second magnified image in the image plane.
8 . The apparatus as claimed in claim 1 , wherein the first homogenization optics arrangement or the second homogenization optics arrangement comprises at least one of: (a) a fly-eye condenser; (b) a rod-homogenizer; or (c) a defocused lens arrangement configured to project a defocused image of a full VCSEL array in the intermediate plane.
9 . The apparatus as claimed in claim 1 ,
wherein neighboring lenses of the first micro lens array have a pitch different than a pitch of neighboring VCSELs of the first array of VCSELs or the second array of VCSELs.
10 . The apparatus as claimed in claim 1 , wherein the first homogenization optics arrangement or the second homogenization optics arrangement and the pattern optics arrangement are a combined and integrally formed arrangement.
11 . The apparatus as claimed in claim 1 , wherein the structured light pattern generated by the pattern optics arrangement comprises a different number of rows or columns than a number of rows or columns of the first array of VCSELs or the second array of VCSELs.
12 . The apparatus as claimed in claim 1 ,
wherein the first homogenization optics arrangement is configured to provide a first top-hat intensity distribution in the intermediate plane based on light emitted by a plurality of VCSELs of the first array of VCSELs;
wherein the second homogenization optics arrangement is configured to provide a second top-hat intensity distribution in the intermediate plane based on light emitted by a plurality of VCSELs of the second array of VCSELs, and
wherein the first top-hat intensity distribution and the second top-hat intensity distribution are adjacent to each other and together form a combined top-hat intensity distribution providing a homogeneous intensity distribution in the intermediate plane.
13 . The apparatus as claimed in claim 1 , the apparatus further comprising a second pattern optics arrangement;
wherein the pattern optics arrangement is configured to generate a first structured light pattern based on a first portion of the common homogeneous intensity distribution in the intermediate plane, and
wherein the second pattern optics arrangement is configured to generate a second structured light pattern based on a second portion of the common homogeneous intensity distribution in the intermediate plane.
14 . The apparatus as claimed in claim 13 ,
wherein the pattern optics arrangement and the second pattern optics arrangement are configured such that the structured light pattern and the second structured light pattern are directed at different regions, and
wherein a separation between the structured light pattern and the second structured light pattern does not exceed a separation between neighboring structures of the structured light pattern.
15 . A system adapted to generate a structured light pattern, the system comprising:
the apparatus as claimed in claim 1 ; and
a controller adapted to control VCSELs of the first array of VCSELs or the second array of VCSELs.
16 . A method for generating a structured light pattern, the method comprising: providing a first array of vertical cavity surface emitting lasers (VCSELs); providing a first homogenization optics arrangement associated with the first array of VCSELs; providing a second array of VCSELs; providing a second homogenization optics arrangement associated with the second array of VCSELs; operating the first array of VCSELs and the second array of VCSELs to generate a common homogeneous intensity distribution in an intermediate plane through the first homogenization optics arrangement and the second homogenization optics arrangement; providing a pattern optics arrangement positioned downstream from the intermediate plane; and generating a structured light pattern based on the common homogeneous intensity distribution in the intermediate plane through the pattern optics arrangement.
17 . The apparatus as claimed in claim 10 , wherein the first homogenization optics arrangement, the second homogenization optics arrangement, and the pattern optics arrangement are an injection-molded integrally formed arrangement.