Optical sensor module including an interferometric sensor and extended depth of focus optics
An optical sensor module includes an interferometric sensor and a set of one or more optical elements. The interferometric sensor includes a coherent light source and at least one detector configured to generate an interferometric signal. The set of one or more optical elements is configured to simultaneously direct a first portion of light emitted by the coherent light source toward a first focus area within a first depth of focus; direct a second portion of the light emitted by the coherent light source toward a second focus area within a second depth of focus; and direct portions of the emitted light that are returned from one or more objects within the first depth of focus or the second depth of focus toward the interferometric sensor.
1. An optical sensor module, comprising:
an interferometric sensor including,
a light source configured to generate and emit a beam of light; and
at least one detector configured to generate an interferometric signal, the interferometric signal based on an at least partially coherent mixing of light that is generated and received by the interferometric sensor; and
a set of one or more optical elements including a zone plate, the zone plate configured to simultaneously,
direct a first portion of the beam of light emitted by the light source toward a first focus area within a first depth of focus;
direct a second portion of the beam of light emitted by the light source toward a second focus area within a second depth of focus; and
direct portions of the emitted beam of light that are returned from one or more objects within the first depth of focus or the second depth of focus toward the interferometric sensor;
the zone plate having,
a first zone that directs the first portion of the emitted beam of light toward the first focus area; and
a second zone, different from the first zone, that directs the second portion of the emitted beam of light toward the second focus area.
2. The optical sensor module of claim 1 , wherein the first zone is configured with a first phase and the second zone is configured with a second phase, the first phase and the second phase constructively interfering in a far field overlap of light passing through the first and second zones.
3. The optical sensor module of claim 1 , wherein the zone plate includes a meta-surface, the meta-surface defining the first zone and the second zone.
4. The optical sensor module of claim 1 , wherein the first zone has a first object-space numerical aperture, and the second zone has a second object-space numerical aperture equal to the first object-space numerical aperture.
5. The optical sensor module of claim 1 , wherein the interferometric sensor includes a self-mixing interferometry sensor.
6. The optical sensor module of claim 1 , wherein the interferometric sensor includes a Mach-Zender interferometer.
7. The optical sensor module of claim 1 , wherein:
the set of one or more optical elements is further configured to, simultaneously with directing the first portion of the beam of light toward the first focus area and directing the second portion of the beam of light toward the second focus area,
direct at least one additional portion of the beam of light emitted by the light source toward at least one additional focus area within at least one additional depth of focus; and
direct at least one additional portion of the emitted beam of light that is returned from one or more objects within the at least one additional depth of focus toward the interferometric sensor.
8. A hand-held input device, comprising:
an elongate housing having a surface contact end;
a set of one or more interferometric sensors mounted to the elongate housing, an interferometric sensor in the set of one or more interferometric sensors including,
a light source configured to generate and emit a beam of light; and
at least one detector configured to generate an interferometric signal in a set of one or more interferometric signals, the interferometric signal based on an at least partially coherent mixing of light that is generated and received by the interferometric sensor;
a set of one or more optical elements including a zone plate, the zone plate configured to, for the interferometric sensor and simultaneously,
direct a first portion of the emitted beam of light toward a first focus area within a first depth of focus near the surface contact end of the elongate housing;
direct a second portion of the emitted beam of light toward a second focus area within a second depth of focus near the surface contact end of the elongate housing; and
direct portions of the emitted beam of light returned from a surface toward the interferometric sensor;
the zone plate having,
a first zone that directs the first portion of the emitted beam of light toward the first focus area; and
a second zone, different from the first zone, that directs the second portion of the emitted beam of light toward the second focus area; and
a processor mounted within the elongate housing and configured to identify an input provided by a user on a surface contacted by the surface contact end of the elongate housing, the input identified at least in part based on the set of one or more interferometric signals generated by the set of one or more interferometric sensors.
9. The hand-held input device of claim 8 , wherein:
the processor is configured to determine, for the interferometric sensor, whether the surface is within the first depth of focus or the second depth of focus; and
identifying the input provided by the user includes determining a movement pattern of the surface contact end with respect to the surface.
10. A wearable device, comprising:
a wearable housing;
a set of one or more interferometric sensors mounted to the wearable housing, an interferometric sensor in the set of one or more interferometric sensors including,
a light source configured to generate and emit a beam of light from the wearable housing; and
at least one detector configured to generate an interferometric signal in a set of one or more interferometric signals, the interferometric signal based on at least partially coherent mixing of light that is generated and received by the interferometric sensor; and
a set of one or more optical elements including a zone plate, the zone plate configured to, for the interferometric sensor and simultaneously,
direct a first portion of the emitted beam of light toward a first focus area within a first depth of focus;
direct a second portion of the emitted beam of light toward a second focus area within a second depth of focus; and
direct portions of the emitted beam of light returned from one or more objects, in the first depth of focus or the second depth of focus, toward the interferometric sensor;
the zone plate having,
a first zone that directs the first portion of the emitted beam of light toward the first focus area; and
a second zone, different from the first zone, that directs the second portion of the emitted beam of light toward the second focus area.
11. The wearable device of claim 10 , wherein:
the wearable housing is a head-mountable housing; and
the interferometric sensor is positioned and oriented to direct the first portion of the emitted beam of light and the second portion of the emitted beam of light toward an eye of a user of the wearable device.
12. The wearable device of claim 10 , wherein:
the wearable housing is a head-mountable housing; and
the interferometric sensor is positioned and oriented to direct at least one of the first portion of the emitted beam of light or the second portion of the emitted beam of light toward a particle flow in and out of a user.
13. The wearable device of claim 10 , wherein:
the wearable housing is a head-mountable housing; and
the interferometric sensor is positioned and oriented to direct the first portion of the emitted beam of light toward a first particle flow in and out of a nose of a user, and to direct the second portion of the emitted beam of light toward a second particle flow in and out of a mouth of the user.
14. An optical sensor module, comprising:
an interferometric sensor including,
a light source configured to generate and emit a beam of light; and
at least one detector configured to generate an interferometric signal, the interferometric signal based on an at least partially coherent mixing of light that is generated and received by the interferometric sensor; and
a set of one or more optical elements including a zone plate, the zone plate configured to simultaneously,
direct a first portion of the beam of light emitted by the light source toward a first focus area within a first depth of focus;
direct a second portion of the beam of light emitted by the light source toward a second focus area within a second depth of focus; and
direct portions of the emitted beam of light that are returned from one or more objects within the first depth of focus or the second depth of focus toward the interferometric sensor;
the zone plate having,
a first set of zones that directs the first portion of the emitted beam of light toward the first focus area; and
at least a second zone, different from the zones in the first set of zones, that directs the second portion of the emitted beam of light toward the second focus area.
15. The optical sensor module of claim 14 , wherein the zone plate includes a meta-surface, the meta-surface defining the first set of zones and the second zone.
16. The optical sensor module of claim 14 , wherein the first set of zones is dispersed within the second zone.
17. The optical sensor module of claim 14 , wherein:
the at least second zone includes a second set of zones; and
the second set of zones is interspersed with the first set of zones.
18. The optical sensor module of claim 14 , wherein the interferometric sensor includes a self-mixing interferometry sensor.
19. The optical sensor module of claim 14 , wherein the interferometric sensor includes a Mach-Zender interferometer.
20. The optical sensor module of claim 14 , wherein:
the set of one or more optical elements is further configured to, simultaneously with directing the first portion of the beam of light toward the first focus area and directing the second portion of the beam of light toward the second focus area,
direct at least one additional portion of the beam of light emitted by the light source toward at least one additional focus area within at least one additional depth of focus; and
direct at least one additional portion of the emitted beam of light that is returned from one or more objects within the at least one additional depth of focus toward the interferometric sensor.