OPTICAL SENSOR, OPTICAL SENSOR SYSTEM, AND ENDOSCOPE

1 . An optical sensor comprising: a light guide member which guides light; a light confinement member which covers an outer peripheral surface of the light guide member to abut on the outer peripheral surface of the light guide member, and confines the light in the light guide member; a protection member which covers an outer peripheral surface of the light confinement member to abut on the outer peripheral surface of the light confinement member, and protects the light confinement member; and characteristic change sections which are in contact with at least the light guide member, and change optical characteristics of the light in accordance with a bending amount of the light guide member,

wherein one characteristic change section and the other characteristic change section are arranged to be close to each other in an area having a desired range,

at least a part of the one characteristic change section is arranged at a position different from at least a part of the other characteristic change section in a circumferential direction of the optical sensor,

at least a part of the one characteristic change section is arranged at a position different from at least a part of the other characteristic change section in an axial direction of the optical sensor,

the one characteristic change section changes the optical characteristics in accordance with the bending amount in one direction of the light guide member in the area,

the other characteristic change section changes the optical characteristics in accordance with the bending amount in the other direction of the light guide member in the area, and

the characteristic change sections change the optical characteristics so that the one optical characteristics changed by the one characteristic change section are different from the other optical characteristics changed by the other characteristic change section, when the optical characteristics of the light change.

2 . The optical sensor according to claim 1 ,

wherein the one overall characteristic change section is arranged at a position different from the other overall characteristic change section in the axial direction of the optical sensor and the circumferential direction of the optical sensor.

3 . The optical sensor according to claim 2 ,

wherein at least one of the one characteristic change section and the other characteristic change section is arranged in a plural number to form one group.

4 . The optical sensor according to claim 3 , wherein the characteristic change sections on one side form a first group,

the characteristic change sections on the other side form a second group, and

the characteristic change sections on one side in the first group and the characteristic change sections on the other side in the second group are alternately arranged in the axial direction of the optical sensor.

5 . The optical sensor according to claim 4 ,

wherein the number of the characteristic change sections on the one side in the first group is equal to the number of the characteristic change sections on the other side in the second group.

6 . The optical sensor according to claim 5 ,

wherein a part of each of the characteristic change sections on the one side in the first group is arranged at a position different from a part of each of the characteristic change sections in the second group in at least one of the circumferential direction of the optical sensor and the axial direction of the optical sensor.

7 . The optical sensor according to claim 6 ,

wherein the characteristic change sections on the one side in the first group are arranged at positions different from the characteristic change sections on the other side in the second group in both the circumferential direction of the optical sensor and the axial direction of the optical sensor.

8 . The optical sensor according to claim 3 ,

wherein the one direction is orthogonal to the other direction.

9 . The optical sensor according to claim 1 , further comprising an inflow preventing section which prevents the characteristic change section from flowing into between the light guide member and the light confinement member.

10 . The optical sensor according to claim 1 ,

wherein the area is provided in a plural number, and

the areas are arranged apart from each other in the axial direction of the optical sensor.

11 . An optical sensor system comprising:

a light source which emits the light toward the light guide member;

the optical sensor according to claim 1 ; and

a detecting section which independently detects the light having the optical characteristics on the one side and the light having the optical characteristics on the other side, and detects mutually different bending directions each other and mutually different bending amounts each other in the optical sensor based on a detection result.

12 . An endoscope comprising the optical sensor system according to claim 11 .