Eye-safe light source
Light emission efficiency is increased in an eye-safe light source by regulating light distribution properties. An eye-safe light source includes a package, a semiconductor laser that emits laser light from a left light emission end surface and a right light emission end surface, and a wire that is joined to the semiconductor laser. The semiconductor laser is joined to the package such that the laser light is emitted parallel to an upper surface of a lead frame of the package. The package includes reflection surfaces that face the left light emission end surface and the right light emission end surface and reflect the laser light. In top view, a direction in which the wire extends is perpendicular to a direction of emission of the laser light.
1. An eye-safe light source comprising:
a substrate;
a semiconductor laser that emits laser light from a light emission end surface; and
a wire that is joined to the semiconductor laser,
wherein the semiconductor laser is joined to the substrate such that the laser light is emitted in a direction parallel to a reference surface of the substrate,
the substrate has a resin part,
the resin part includes a reflection surface that faces the light emission end surface and reflects the laser light,
a direction in which the wire extends when seen from a direction perpendicular to the reference surface is perpendicular to a direction of emission of the laser light from the light emission end surface,
the reflection surface is covered with metal,
the substrate includes a metal lead frame and a resin that at least partially covers the metal lead frame, and
the semiconductor laser is joined to the metal lead frame.
2. The eye-safe light source according to claim 1 , wherein
light emission end surfaces are disposed on both sides of the semiconductor laser, and
reflection surfaces are disposed on both sides of the semiconductor laser to face the light emission end surfaces.
3. The eye-safe light source according to claim 2 , wherein
the light emission end surfaces are optically symmetric to each other,
the reflection surfaces have plane symmetry about a plane of symmetry, and
the plane of symmetry is a plane that passes through a center of the semiconductor laser and is perpendicular to the direction of emission of the laser light from the light emission end surfaces.
4. The eye-safe light source according to claim 1 , wherein
the light emission end surface is disposed on one side of the semiconductor laser, and
the reflection surface is disposed on the one side of the semiconductor laser to face the light emission end surface.
5. The eye-safe light source according to claim 4 , wherein
the reflection surface has plane symmetry about a plane of symmetry, and
the plane of symmetry is a plane that passes through a light emission center of the light emission end surface and is perpendicular to the reference surface and parallel to the direction of emission of the laser light from the light emission end surface.
6. The eye-safe light source according to claim 1 , wherein
a light scattering body that scatters the laser light is not present between the light emission end surface and the reflection surface facing the light emission end surface.
7. The eye-safe light source according to claim 1 , wherein
the laser light that is reflected by the reflection surface is transmitted through a light scattering layer including a light scattering body that scatters the laser light.
8. The eye-safe light source according to claim 1 , wherein
the reflection surface includes a part of a curved surface composed of a parabola.
9. The eye-safe light source according to claim 8 , wherein
the curved surface is a surface of a solid of revolution that is drawn by a trajectory of rotation of the parabola when the parabola is rotated about an axis of symmetry of the parabola as an axis of rotation, or an axis inclined with respect to the axis of symmetry of the parabola as an axis of rotation.
10. The eye-safe light source according to claim 8 , wherein
a position of a focus of the parabola matches a position of the light emission end surface in the direction perpendicular to the reference surface.
11. An eye-safe light source comprising:
a substrate;
a semiconductor laser that emits laser light from a light emission end surface; and
a wire that is joined to the semiconductor laser,
wherein the semiconductor laser is joined to the substrate such that the laser light is emitted in a direction parallel to a reference surface of the substrate,
the substrate has a resin part,
the resin part includes a reflection surface that faces the light emission end surface and reflects the laser light,
a direction in which the wire extends when seen from a direction perpendicular to the reference surface is perpendicular to a direction of emission of the laser light from the light emission end surface,
the reflection surface is covered with metal,
the semiconductor laser is joined to the substrate with a submount in between such that the light emission end surface extends over the submount when seen from the direction perpendicular to the reference surface.
12. The eye-safe light source according to claim 11 , wherein
light emission end surfaces are disposed on both sides of the semiconductor laser, and
reflection surfaces are disposed on both sides of the semiconductor laser to face the light emission end surfaces.
13. The eye-safe light source according to claim 12 , wherein
the light emission end surfaces are optically symmetric to each other,
the reflection surfaces have plane symmetry about a plane of symmetry, and
the plane of symmetry is a plane that passes through a center of the semiconductor laser and is perpendicular to the direction of emission of the laser light from the light emission end surfaces.
14. The eye-safe light source according to claim 11 , wherein
the light emission end surface is disposed on one side of the semiconductor laser, and
the reflection surface is disposed on the one side of the semiconductor laser to face the light emission end surface.
15. The eye-safe light source according to claim 14 , wherein
the reflection surface has plane symmetry about a plane of symmetry, and
the plane of symmetry is a plane that passes through a light emission center of the light emission end surface and is perpendicular to the reference surface and parallel to the direction of emission of the laser light from the light emission end surface.
16. The eye-safe light source according to claim 11 , wherein
a light scattering body that scatters the laser light is not present between the light emission end surface and the reflection surface facing the light emission end surface.
17. The eye-safe light source according to claim 11 , wherein
the laser light that is reflected by the reflection surface is transmitted through a light scattering layer including a light scattering body that scatters the laser light.
18. The eye-safe light source according to claim 11 , wherein
the reflection surface includes a part of a curved surface composed of a parabola.
19. The eye-safe light source according to claim 18 , wherein
the curved surface is a surface of a solid of revolution that is drawn by a trajectory of rotation of the parabola when the parabola is rotated about an axis of symmetry of the parabola as an axis of rotation, or an axis inclined with respect to the axis of symmetry of the parabola as an axis of rotation.
20. The eye-safe light source according to claim 18 , wherein
a position of a focus of the parabola matches a position of the light emission end surface in the direction perpendicular to the reference surface.