Light source device, image sensor, and sensing module
Exposure with sufficient optical energy is enabled while avoiding temperature rise of laser light emitting elements. Therefore, a light source device includes the plurality of laser light emitting elements and a drive unit. The drive unit drives each of the laser light emitting elements to perform a plurality of light emissions in one frame period in an image sensor that receives and captures light emitted from the plurality of laser light emitting elements and reflected by a subject.
1. A light source device comprising:
a plurality of laser light emitting elements; and
a drive unit configured to drive the laser light emitting elements to emit a plurality of light pulses in one frame period of a pixelated image sensor configured to receive and capture light emitted from the plurality of laser light emitting elements and reflected by a subject,
wherein the pixelated image sensor is configured to generate a synchronization signal for the plurality of laser light emitting elements to synchronize the plurality of light pulses with a corresponding plurality of exposure periods in the one frame period of the pixelated image sensor; and
wherein, in response to the synchronization signal, the drive circuit is configured to synchronize the plurality of light pulses with the corresponding plurality of exposure periods in the one frame period of the pixelated image sensor.
2. The light source device according to claim 1 , wherein
the drive unit is further configured to change a number of the light pulses of the laser light emitting elements in the one frame period of the pixelated image sensor according to a temperature detection result.
3. The light source device according to claim 1 , wherein
the laser light emitting elements include vertical cavity surface emitting lasers.
4. The light source device according to claim 1 , further comprising
a temperature sensor configured to detect a temperature in a chip near the laser light emitting elements therein.
5. The light source device according to claim 1 , further comprising
a temperature sensor configured to detect a temperature near the laser light emitting elements,
wherein the drive unit is further configured to change a cycle of the light pulses of the laser light emitting elements in the one frame period of the pixelated image sensor according to a detection result of the temperature sensor.
6. The light source device according to claim 1 , wherein
the drive unit is further configured to drive each of the laser light emitting elements according to a light emission parameter defining a light emission operation of the laser light emitting elements per predetermined unit.
7. The light source device according to claim 1 , wherein
the drive unit is further configured to drive each of the laser light emitting elements according to a light emission parameter defining a light emission operation of the laser light emitting elements, and
the light source device comprises a control unit configured to generate the light emission parameter.
8. The light source device according to claim 1 , wherein
the drive unit is further configured to control duration time of one light pulse of the plurality of light pulses using a set light emission parameter.
9. The light source device according to claim 1 , wherein
the drive unit is further configured to control a light emission interval of the plurality of light pulses using a set light emission parameter.
10. An image sensor, comprising
a pixelated image sensor including a photoelectric conversion unit configured, in a case where a plurality of laser light emitting elements of a light source device emits a plurality of light pulses in one frame period in which a captured image is generated by the pixelated image sensor, to perform exposure to light emitted from the laser light emitting elements and reflected by a subject in an exposure period corresponding to a period of the light pulses,
wherein the pixelated image sensor is configured to output data of one-frame captured image obtained using a plurality of the exposure periods; and
wherein the pixelated image sensor is further configured to generate a synchronization signal for the light source to synchronize the plurality of light pulses with a corresponding plurality of exposure periods in the one frame period of the pixelated image sensor.
11. The image sensor according to claim 10 , further comprising
a charge holding unit configured to hold a charge by the exposure of the photoelectric conversion unit according to the period of the light pulses of the laser light emitting elements in one frame period of the pixelated image sensor,
wherein a charge signal corresponding to one image in each frame period of the pixelated image sensor is read from the charge holding unit.
12. The image sensor according to claim 10 , wherein
the photoelectric conversion unit allows settings of:
an operation of performing exposure corresponding to the period of light pulses in one frame period of the pixelated image sensor, and
an operation of performing exposure corresponding to a part of the period of the light pulses.
13. A sensing module, comprising:
a plurality of laser light emitting elements;
a drive unit configured to drive each of the laser light emitting elements to emit a plurality of light pulses in one frame period of a pixelated image sensor configured to receive and capture light emitted from the plurality of laser light emitting elements and reflected by a subject; and
the pixelated image sensor including a photoelectric conversion unit configured to perform exposure to the light emitted from the laser light emitting elements and reflected by the subject in an exposure period corresponding to a period of the light pulses, the pixelated image sensor outputting data of one-frame captured image data obtained by a plurality of the exposure periods; and
wherein the pixelated image sensor is configured to generate a synchronization signal for the plurality of laser light emitting elements to synchronize the plurality of light pulses with a corresponding plurality of exposure periods in the one frame period of the pixelated image sensor.
14. The sensing module according to claim 13 , further comprising
a temperature sensor configured to detect a temperature near the laser light emitting elements,
wherein the drive unit is further configured to change a number of the light pulses of the laser light emitting elements in one frame period of the pixelated image sensor according to a temperature detection result by the temperature sensor.