Light-emitting device, optical device, measurement device, and information processing apparatus
A light-emitting device includes a laser element array having a quadrangular planar shape, a pair of capacitors that supply an electric current for light emission of the laser element array, and a driving unit that drives the laser element array by turning on and off the electric current for light emission of the laser element array. The pair of capacitors are disposed beside two sides of the laser element array that face each other so as to sandwich the laser element array, and the driving unit is disposed beside another side of the laser element array.
1. A light-emitting device comprising:
a laser element array having a quadrangular planar shape, the laser element array including an anode electrode;
a first pair of capacitors that supply an electric current for light emission of the laser element array, each capacitor of the first pair of capacitors being electrically connected to anode wires, respectively;
a driving unit that drives the laser element array by turning on and off the electric current for light emission of the laser element array; and
a pair of bonding wires, each bonding wire directly connecting the anode electrode of the laser element array to a respective one of the anode wires, wherein
the first pair of capacitors are disposed beside two sides of the laser element array that face each other so as to sandwich the laser element array,
the driving unit is disposed beside another side of the laser element array, and
the anode electrode is different from the anode wires.
2. The light-emitting device according to claim 1 , wherein
the driving unit includes a driving element that turns on and off the electric current for light emission of the laser element array; and
the laser element array and the driving element are connected to each other so that the laser element array is driven by low-side driving in which the driving element is provided on a downstream side of an electric current path relative to the laser element array.
3. The light-emitting device according to claim 1 , further comprising a circuit board on which the laser element array and the driving unit are mounted, wherein
the laser element array and the driving unit are provided on a front surface of the circuit board, and
the circuit board has a reference potential wire as a layer.
4. The light-emitting device according to claim 2 , further comprising a circuit board on which the laser element array and the driving unit are mounted, wherein
the laser element array and the driving unit are provided on a front surface of the circuit board, and
the circuit board has a reference potential wire as a layer.
5. The light-emitting device according to claim 3 , further comprising a heat releasing base member having higher thermal conductivity than the circuit board, wherein
the laser element array is provided on the heat releasing base member, and the heat releasing base member is mounted on the circuit board.
6. The light-emitting device according to claim 5 , wherein
the laser element array includes a plurality of surface emitting laser elements that are connected in parallel and has a cathode electrode on a rear surface side thereof and the anode electrode on a front surface side thereof.
7. The light-emitting device according to claim 6 , wherein
the heat releasing base member has, on a front surface side thereof, a front-surface-side cathode wire connected to the cathode electrode of the laser element array and a pair of front-surface-side anode wires of the anode wires connected to the anode electrode of the laser element array so as to sandwich the front-surface-side cathode wire and has, on a rear surface side thereof, a rear-surface-side cathode wire and a pair of rear-surface-side anode wires of the anode wires that are provided at positions corresponding to the front-surface side cathode wire and the pair of front-surface-side anode wires and are electrically connected to the front-surface side cathode wire and the pair of front-surface-side anode wires, respectively.
8. The light-emitting device according to claim 1 , further comprising a diffusion member that diffuses light emitted from the laser element array and outputs the diffused light.
9. The light-emitting device according to claim 2 , further comprising a diffusion member that diffuses light emitted from the laser element array and outputs the diffused light.
10. The light-emitting device according to claim 1 , further comprising a diffraction member that diffracts light emitted from the laser element array and outputs the diffracted light.
11. The light-emitting device according to claim 1 , further comprising a light amount monitoring light receiving element that monitors a light amount of the laser element array.
12. An optical device comprising:
the light-emitting device according to claim 1 ; and
a light receiving unit that receives light emitted from the laser element array of the light-emitting device and then reflected by an object to be measured.
13. A measurement device comprising:
the optical device according to claim 12 ; and
a distance specifying unit that specifies a distance to an object to be measured on a basis of a period from emission of light from the laser element array of the optical device to reception of the light by the light receiving unit.
14. An information processing apparatus comprising:
the measurement device according to claim 13 ; and
an authentication processing unit that performs authentication processing concerning use of the information processing apparatus on a basis of the distance specified by the distance specifying unit of the measurement device.
15. The light-emitting device according to claim 1 , further comprising a second pair of capacitors,
wherein a first capacitor of the first pair of capacitors and a second capacitor of the second pair of capacitors are disposed beside a same side of the laser element array and have different lengths.
16. The light-emitting device according to claim 15 , wherein the first capacitor has a smaller capacity than the second capacitor.
17. The light-emitting device according to claim 16 , wherein the first capacitor has a larger planar shape than the second capacitor.
18. The light-emitting device according to claim 16 , wherein the first capacitor supplies to the light source when increasing the light emission.