Optical system for full frame flash solid state LIDAR system
A solid-state optical system comprising: a sensor array having a field of view; an emitter array comprising a plurality of emitter units mounted on a surface of a common substrate and arranged in a two-dimensional array, wherein each emitter unit in the plurality of emitter units is spaced apart from its adjacent emitter units by a first distance and emits pulses of light having a predetermined beam divergence; an optical element comprising a plurality of lenses corresponding in number to the plurality of emitter units and arranged in a two-dimensional array in which adjacent optical elements in the two-dimensional array are spaced apart from each other by the first distance, wherein the optical element is positioned adjacent to the emitter array such that each lens in the plurality of lenses is spaced apart from and receives the pulses of light emitted from a corresponding one of the emitter units in the plurality of emitter units and is configured to reduce the angle of divergence of the pulses of light emitted by its corresponding emitter unit; and a diffuser disposed adjacent to the optical element and configured to spread light received from the optical element across the entire field of view of the sensor array.
1 . A solid-state optical system comprising:
a sensor array having a field of view;
an emitter array comprising a plurality of emitter units mounted on a surface of a common substrate and arranged in a two-dimensional array, wherein each emitter unit in the plurality of emitter units is spaced apart from its adjacent emitter units by a first distance, and each emitter unit comprises one or more vertical cavity surface emitting laser (VCSEL) chips with each VCSEL chip having a plurality of densely packed VCSELs formed on the chip that combine to emit pulses of light away from the VCSEL chip in a light cone having a predetermined beam divergence;
an optical element comprising a plurality of lenses corresponding in number to the plurality of emitter units and arranged in a two-dimensional array in which adjacent optical elements in the two-dimensional array are spaced apart from each other by the first distance, wherein the optical element is positioned adjacent to the emitter array such that each lens in the plurality of lenses is spaced apart from and receives the pulses of light emitted from a corresponding one of the emitter units in the plurality of emitter units and is configured to reduce the angle of divergence of the pulses of light emitted by its corresponding emitter unit; and
a diffuser disposed adjacent to the optical element with the optical element positioned between the emitter array and the diffuser, wherein the diffuser has a single diffusion profile extending across its entire optical surface and is configured to spread light received from the optical element over a field of illumination of the emitter array;
wherein each lens in the plurality of lenses within the optical element comprises a Fresnel lens.
2 . The solid-state optical system set forth in claim 1 wherein each emitter unit consists of a single VCSEL chip.
3 . The solid-state optical system set forth in claim 2 wherein each VCSEL chip comprises more than one hundred individual densely packed VCSELs.
4 . The solid-state optical system set forth in claim 1 wherein each emitter unit consists of a plurality of VCSEL chips arranged directly adjacent each other.
5 . The solid-state optical system set forth in claim 1 wherein the sensor array comprises a plurality of sensors and wherein each sensor in the plurality of sensors comprises a plurality of single photon avalanche detectors (SPADs).
6 . The solid-state optical system set forth in claim 1 wherein the optical element and diffuser are each fabricated from separate sheets of transparent material and bonded together.
7 . The solid-state optical system set forth in claim 6 wherein the transparent material is polycarbonate.
8 . The solid-state optical system set forth in claim 1 wherein the optical element and diffuser are fabricated from a single sheet of transparent material.
9 . The solid-state optical system set forth in claim 1 further comprising a plurality of emitter driver circuits, each emitter driver circuit coupled to a unique subset of the emitter units and configured to simultaneously fire all of the emitter units in its unique subset.
10 . The solid-state optical system set forth in claim 9 wherein each of the emitter driver circuits comprises one or more capacitors and a switching transistor with its respective unique subset of emitter units coupled in series between the one or more capacitors and switching transistor.
11 . The solid-state optical system set forth in claim 10 wherein, for each driver circuit in the plurality of driver circuits, the unique subset of emitter units coupled to the driver circuit are arranged in a single column of the emitter array.
12 . The solid-state optical system set forth in claim 11 where driver circuits in columns adjacent to each other are configured to drive current through their respective unique subsets of emitter units in opposite directions.
13 . The solid-state optical system set forth in claim 11 further comprising a plurality of conductive pads corresponding in number to the plurality of emitter units, and wherein each emitter unit is bonded directly to a first end of a corresponding conductive pad with a length of the corresponding conductive pad extending to a second end of the corresponding conductive pad, opposite the first end, and such that each column of the emitter array comprises a subset of the plurality of conductive pads extending first end to second end along a length of the column.
14 . The solid-state optical system set forth in claim 13 further comprising: a ground plane formed beneath the surface of the common substrate and a heat sink, and wherein each conductive pad includes a plurality of vias extending perpendicularly from the conductive pad through the ground plane to the heat sink.