Light source apparatus for endoscope, endoscope, and endoscope system

1. A light source apparatus for an endoscope, comprising:

an optical fiber having a fiber end face, the optical fiber being configured to guide emission light emitted from a light source and incident on the fiber end face;

a ferrule having a ferrule end face, the ferrule having an opening of a through-hole on the ferrule end face, the optical fiber being inserted into the through-hole;

a holder to which the ferrule is fixed, the holder having a reflecting surface configured to reflect first reflected light to thereby emit second reflected light, the first reflected light being the emission light reflected on the fiber end face; and

an optical sensor having a light receiving surface configured to receive the second reflected light, the optical sensor being disposed between the light source and the fiber end face and in a region facing the reflecting surface through an optical axis.

2. The light source apparatus for the endoscope according to claim 1 , further comprising a lens fixed to the holder, the lens being configured to collect the emission light on the fiber end face, wherein

the holder has an inner surface surrounding a space including an optical path of the emission light to be collected by the lens, and

the optical sensor is disposed between the lens and the fiber end face.

3. The light source apparatus for the endoscope according to claim 2 , wherein the reflecting surface is a scattering surface configured to scatter and reflect the first reflected light, and the second reflected light is scattered reflected light.

4. The light source apparatus for the endoscope according to claim 3 , wherein

the scattering surface is a first region on the inner surface on which the first reflected light is directly incident, and

the optical sensor is disposed in a second region on the inner surface, the second region being located outside the optical path and facing the first region through the optical axis.

5. The light source apparatus for the endoscope according to claim 2 , wherein the optical sensor is disposed in a recess on the inner surface.

6. The light source apparatus for the endoscope according to claim 5 , wherein, in the optical sensor, the light receiving surface is disposed deeper in the recess than an opening surface of the recess.

7. The light source apparatus for the endoscope according to claim 2 , further comprising a light absorbing member disposed around the optical sensor, the light absorbing member having a reflectance of 10% or less.

8. The light source apparatus for the endoscope according to claim 2 , wherein the optical sensor includes a light amount reducing member configured to reduce an amount of the second reflected light incident on the optical sensor.

9. The light source apparatus for the endoscope according to claim 2 , wherein

the fiber end face is inclined with respect to a plane perpendicular to the optical axis, and

the first reflected light is emitted in a direction of a position facing an arrangement position of the optical sensor through the optical axis.

10. The light source apparatus for the endoscope according to claim 2 , wherein a numerical aperture of the lens is equal to or less than a numerical aperture of the optical fiber.

11. The light source apparatus for the endoscope according to claim 2 , wherein

a numerical aperture of the lens exceeds a numerical aperture of the optical fiber, and

the first reflected light includes the emission light reflected by the ferrule end face.

12. The light source apparatus for the endoscope according to claim 1 , further comprising a controller configured to adjust an amount of the emission light by controlling the light source according to an output of the optical sensor.

13. The light source apparatus for the endoscope according to claim 1 , wherein the emission light is illumination light.

14. An endoscope comprising a light source apparatus for the endoscope, wherein the light source apparatus for the endoscope comprises:

an optical fiber having a fiber end face, the optical fiber being configured to guide emission light emitted from a light source and incident on the fiber end face;

a ferrule having a ferrule end face, the ferrule having an opening of a through-hole on the ferrule end face, the optical fiber being inserted into the through-hole;

a holder to which the ferrule is fixed, the holder having a reflecting surface configured to reflect first reflected light to thereby emit second reflected light, the first reflected light being the emission light reflected on the fiber end face; and

an optical sensor having a light receiving surface configured to receive the second reflected light, the optical sensor being disposed between the light source and the fiber end face and in a region facing the reflecting surface through an optical axis.

15. An endoscope system comprising an endoscope and a light source apparatus for the endoscope, wherein the light source apparatus for the endoscope comprises:

an optical fiber having a fiber end face, the optical fiber being configured to guide emission light emitted from a light source and incident on the fiber end face;

a ferrule having a ferrule end face, the ferrule having an opening of a through-hole on the ferrule end face, the optical fiber being inserted into the through-hole;

a holder to which the ferrule is fixed, the holder having a reflecting surface configured to reflect first reflected light to thereby emit second reflected light, the first reflected light being the emission light reflected on the fiber end face; and

an optical sensor having a light receiving surface configured to receive the second reflected light, the optical sensor being disposed between the light source and the fiber end face and in a region facing the reflecting surface through an optical axis.