Modular optics for scanning engine having beam combining optics with a prism intercepted by both beam axis and collection axis

1. An optoelectronic module, comprising:

a beam transmitter, configured to emit at least one beam of light along a beam axis;

a receiver, configured to sense the light received by the module along a collection axis of the receiver, which is parallel to the beam axis within the module; and

beam-combining optics, configured to direct the beam and the received light so that the beam axis is aligned with the collection axis outside the module, and comprising a prism having multiple faces including at least a first face configured for internal reflection and a second face comprising a beamsplitter, which is intercepted by both the beam axis and the collection axis,

wherein the beam axis enters and exits the faces of the prism at entrance and exit angles in a vicinity of a minimum deviation angle.

2. The module according to claim 1 , wherein the first and second faces are parallel to one another.

3. The module according to claim 1 , wherein both the beam axis and the collection axis pass through the second face at different, respective locations.

4. The module according to claim 1 , and comprising a micro-optical substrate, wherein the beam transmitter comprises a laser die, and the receiver comprises a detector die, both of which are mounted on the micro-optical substrate.

5. The module according to claim 1 , and comprising a filter formed on one of the faces so as to exclude the received light that is outside an emission band of the beam transmitter.

6. The module according to claim 1 , wherein the beamsplitter comprises a polarizing beamsplitter coating on the second face.

7. The module according to claim 1 , wherein the multiple faces comprise a third face through which the beam axis and the collection axis exit the module at a location on the third face that is common to both the beam axis and the collection axis.

8. The module according to claim 1 , wherein the beam-combining optics comprise at least one lens, which is configured to collimate the at least one laser beam and to focus the received light onto the detector die.

9. An optical scanning head, which comprises the module according to claim 1 and a scanning mirror, which is configured to scan both the beam axis and the collection axis together over a scan area.

10. An optical method, comprising:

emitting at least one beam of light toward a scanner along a beam axis from a beam transmitter in an optoelectronic module;

receiving the light from the scanner along a collection axis, which is parallel to the beam axis within the optoelectronic module; and

directing the beam and the received light to and from the scanner so that the beam axis is aligned with the collection axis at the scanner, using beam-combining optics comprising a prism having multiple faces including at least a first face configured for internal reflection and a second face comprising a beamsplitter, which is intercepted by both the beam axis and the collection axis,

wherein the beam axis enters and exits the faces of the prism at entrance and exit angles in a vicinity of a minimum deviation angle.

11. The method according to claim 10 , wherein the first and second faces are parallel to one another.

12. The method according to claim 10 , wherein both the beam axis and the collection axis pass through the second face at different, respective locations.

13. The method according to claim 10 , and comprising forming a filter on one of the faces so as to exclude the received light that is outside an emission band of the beam transmitter.

14. The method according to claim 10 , wherein the beamsplitter comprises a polarizing beamsplitter coating on the second face.

15. The method according to claim 10 , wherein the multiple faces comprise a third face through which the beam axis and the collection axis exit the optoelectronic module at a location on the third face that is common to both the beam axis and the collection axis.

16. The method according to claim 10 , wherein directing the laser beam and the received light comprises applying at least one lens to collimate the at least one laser beam and to focus the light received from the scanner.

17. The method according to claim 10 , and comprising scanning both the beam axis and the collection axis together over a scan area using the scanner.

18. The method according to claim 17 , wherein emitting the at least one beam comprises emitting pulses of the light, and wherein receiving the light comprises measuring respective times of flight of the pulses to and from objects in the scan area.