Overlapping pattern projector
An optoelectronic device includes a semiconductor substrate, an array of optical emitters arranged on the substrate in a two-dimensional pattern, a projection lens and a diffractive optical element (DOE). The projection lens is mounted on the semiconductor substrate and is configured to collect and focus light emitted by the optical emitters so as to project optical beams containing a light pattern corresponding to the two-dimensional pattern of the optical emitters on the substrate. The DOE is mounted on the substrate and is configured to produce and project multiple overlapping replicas of the pattern.
1. An optoelectronic device, comprising:
a semiconductor substrate;
an array of optical emitters, arranged on the substrate in a two-dimensional pattern;
a projection lens, which is mounted on the semiconductor substrate and is configured to collect and focus light emitted by the optical emitters so as to project optical beams containing a baseline light pattern having a given pitch, corresponding to the two-dimensional pattern of the optical emitters on the substrate; and
a diffractive optical element (DOE), which is mounted on the substrate and is configured to produce and project multiple overlapping replicas of the baseline light pattern with a composite pattern density that is finer than the pitch of the baseline light pattern.
2. The device according to claim 1 , wherein the optical emitters comprise vertical cavity surface emitting laser (VCSEL) devices.
3. The device according to claim 1 , wherein the DOE is configured to produce the multiple replicas so as to overlap in one dimension.
4. The device according to claim 1 , wherein the DOE is configured to produce the multiple replicas so as to overlap in two dimensions.
5. The device according to claim 1 , wherein the two-dimensional pattern of the optical emitters does not lie on a regular lattice.
6. The device according to claim 1 , wherein the two-dimensional pattern of the optical emitters is an uncorrelated pattern.
7. The device according to claim 1 , wherein the two-dimensional pattern of the optical emitters is a regular grid pattern.
8. The device according to claim 1 , wherein the projection lens and the DOE are formed on a single optical substrate.
9. The device according to claim 1 , wherein the two-dimensional pattern of the optical emitters is divided into two or more subsets that are individually addressable, and comprising control circuitry that is configured to address combinations of one or more of the subsets so as to control the overlapping replicas for creating multiple different pattern densities.
10. The device according to claim 1 , wherein the DOE is configured to create transversal offsets between duplication in adjacent columns of the projected optical beams, so as to reduce an ambiguity in depth estimation that is based on measuring transversal shifts in the projected optical beams along the columns.
11. A method for producing an optoelectronic device, the method comprising:
providing a semiconductor substrate;
forming an array of optical emitters on the substrate in a two-dimensional pattern;
mounting a projection lens on the semiconductor substrate so as to collect and focus light emitted by the optical emitters, thereby projecting optical beams containing a baseline light pattern having a given pitch, corresponding to the two-dimensional pattern of the optical emitters on the substrate; and
mounting a diffractive optical element (DOE) on the substrate so as to produce and project multiple overlapping replicas of the baseline light pattern with a composite pattern density that is finer than the pitch of the baseline light pattern.
12. The method according to claim 11 , wherein the optical emitters comprise vertical cavity surface emitting laser (VCSEL) devices.
13. The method according to claim 11 , wherein the multiple replicas produced by the DOE overlap in one dimension.
14. The method according to claim 11 , wherein the multiple replicas produced by the DOE overlap in two dimensions.
15. The method according to claim 11 , wherein the two-dimensional pattern of the optical emitters does not lie on a regular lattice.
16. The method according to claim 11 , wherein the two-dimensional pattern of the optical emitters is an uncorrelated pattern.
17. The method according to claim 11 , wherein the two-dimensional pattern of the optical emitters is a regular grid pattern.
18. The method according to claim 11 , wherein mounting the projection lens and the DOE comprises forming the projection lens and the DOE on a single optical substrate.
19. The method according to claim 11 , wherein the two-dimensional pattern of the optical emitters is divided into two or more subsets that are individually addressable, and comprising providing control circuitry that addresses combinations of one or more of the subsets so as to control the overlapping replicas for creating multiple different pattern densities.
20. The method according to claim 11 , wherein the DOE creates transversal offsets between adjacent columns of the projected optical beams, so as to reduce an ambiguity in depth estimation that is based on measuring transversal shifts in the projected optical beams along the columns.