Multi-channel light detection and ranging (LIDAR) unit having a telecentric lens assembly and single circuit board for emitters and detectors
A LIDAR unit includes a housing defining a cavity. The LIDAR unit further include a plurality of emitters disposed on a circuit board within the cavity. Each of the emitters emits a laser beam along a transmit path. The LIDAR system further includes a first telecentric lens assembly positioned within the cavity and along the transmit path such that the laser beam emitted from each of the plurality of emitters passes through the first telecentric lens assembly. The LIDAR further includes a second telecentric lens assembly positioned within the cavity and along a receive path such that a plurality of reflected laser beams entering the cavity pass through the second telecentric lens assembly. The first telecentric lens assembly and the second telecentric lens assembly each include a field flattening lens and at least one other lens.
1. A light detection and ranging (LIDAR) system for a vehicle, comprising:
a plurality of emitters disposed on a first portion of a circuit board, the plurality of emitters respectively configured to emit a laser beam;
a first optical element assembly configured to receive the laser beam, wherein the first optical element assembly comprises a first field flattening optical element;
a second optical element assembly configured to receive a plurality of reflected laser beams, wherein the second optical element assembly comprises a second field flattening optical element, the first field flattening optical element being thinner than the second field flattening optical element; and
a plurality of detectors disposed on a second portion of the circuit board, spaced apart from the plurality of emitters in a first direction, the plurality of detectors respectively configured to receive the plurality of reflected laser beams through the second optical element assembly,
wherein at least one of the plurality of emitters comprises:
a laser diode configured to emit the laser beam parallel to the circuit board in the first direction; and
a collimation optical element configured to reflect the laser beam towards the first optical element assembly.
2. The LIDAR system of claim 1 , wherein:
the first optical element assembly comprises at least one other first optical element, the first field flattening optical element being positioned between the plurality of emitters and the at least one other first optical element; and
the second optical element assembly comprises at least one other second optical element, the second field flattening optical element being positioned between the plurality of detectors and the at least one other second optical element.
3. The LIDAR system of claim 2 , further comprising:
a housing defining a cavity; and
an optical filter disposed within the cavity between the plurality of detectors and the second field flattening optical element.
4. The LIDAR system of claim 3 , wherein the optical filter comprises a bandpass filter.
5. The LIDAR system of claim 3 , wherein the plurality of reflected laser beams exits the second field flattening optical element in a direction substantially perpendicular to a surface of the optical filter.
6. The LIDAR system of claim 5 , wherein an acceptance angle of the optical filter is between 1.6 degrees and 2.4 degrees.
7. The LIDAR system of claim 1 , wherein the plurality of detectors are spaced apart from the plurality of emitters in the first direction by a distance corresponding to a thickness of the second optical element assembly.
8. The LIDAR system of claim 1 , further comprising a housing defining a cavity, wherein the circuit board is positioned in the cavity and the housing includes a partition wall dividing the cavity into a first portion in which the first optical element assembly is positioned and a second portion in which the second optical element assembly is positioned.
9. The LIDAR system of claim 1 , wherein the first optical element assembly is different from the second optical element assembly.
10. The LIDAR system of claim 1 , wherein at least one of the plurality of detectors comprises an avalanche photodiode.
11. The LIDAR system of claim 1 , wherein:
the first field flattening optical element has a thickness of about 3 millimeters; and
the second field flattening optical element has a thickness of about 4 millimeters.
12. An autonomous vehicle, comprising:
a light detection and ranging (LIDAR) system comprising:
a plurality of emitters disposed on a first portion of a circuit board, the plurality of emitters respectively configured to emit a laser beam;
a first optical element assembly configured to receive the laser beam, wherein the first optical element assembly comprises a first field flattening optical element;
a second optical element assembly configured to receive a plurality of reflected laser beams, wherein the second optical element assembly comprises a second field flattening optical element, the first field flattening optical element being thinner than the second field flattening optical element; and
a plurality of detectors disposed on a second portion of the circuit board, spaced apart from the plurality of emitters in a first direction, the plurality of detectors respectively configured to receive the plurality of reflected laser beams by way of the second optical element assembly,
wherein at least one of the plurality of emitters comprises:
a laser diode configured to emit the laser beam parallel to the circuit board in the first direction; and
a collimation optical element configured to reflect the laser beam towards the first optical element assembly; and
one or more processors configured to control an operation of the autonomous vehicle based on information associated with the plurality of reflected laser beams.
13. The autonomous vehicle of claim 12 , wherein:
the first optical element assembly comprises at least one other first optical element, the first field flattening optical element being positioned between the plurality of emitters and the at least one other first optical element, and
the second optical element assembly comprises at least one other second optical element, the second field flattening optical element being positioned between the plurality of detectors and the at least one other second optical element.
14. The autonomous vehicle of claim 13 , wherein the LIDAR system further comprises:
a housing defining a cavity; and
an optical filter disposed within the cavity between the plurality of detectors and the second field flattening optical element.
15. The autonomous vehicle of claim 12 , wherein a surface of the circuit board on which the plurality of emitters are disposed is substantially flat.
16. The autonomous vehicle of claim 12 , wherein at least one of the plurality of detectors comprises an avalanche photodiode.
17. The autonomous vehicle of claim 12 , wherein:
the LIDAR system further comprises a housing defining a cavity,
the circuit board is positioned in the cavity, and
the housing includes a partition wall dividing the cavity into a first portion in which the first optical element assembly is positioned and a second portion in which the second optical element assembly is positioned.
18. An autonomous vehicle control system, comprising:
a light detection and ranging (LIDAR) system comprising:
a plurality of emitters disposed on a first portion of a circuit board, the plurality of emitters respectively configured to emit a laser beam;
a first optical element assembly configured to receive the laser beam, wherein the first optical element assembly comprises a first field flattening optical element;
a second optical element assembly configured to receive a plurality of reflected laser beams, wherein the second optical element assembly comprises a second field flattening optical element, the first field flattening optical element being thinner than the second field flattening optical element; and
a plurality of detectors disposed on a second portion of the circuit board, spaced apart from the plurality of emitters in a first direction, the plurality of detectors respectively configured to receive the plurality of reflected laser beams by way of the second optical element assembly,
wherein at least one of the plurality of emitters comprises:
a laser diode configured to emit the laser beam parallel to the circuit board in the first direction; and
a collimation optical element configured to reflect the laser beam towards the first optical element assembly; and
one or more processors configured to control an operation of a vehicle system based on information associated with the plurality of reflected laser beams.