Probe
An acoustic wave detector that detects an acoustic wave from a subject, an optical fiber that guides light emitted from a light source to a probe body, and a light guide member that guides light from a light entrance end, which is optically coupled to the optical fiber, to a light exit end, which is located in the vicinity of the acoustic wave detector, are provided. The light guide member is secured in the probe body with a securing material provided at least partially around the light guide member. The conditional expression below is satisfied: sin −1 ( n 2/ n 1)×(180°/π)<90°−θ i where n1 is a refractive index of the light guide member, n2 is a refractive index of the securing material, and θi is a spread angle of incoming light from the optical fiber.
1. A probe comprising:
an acoustic wave detector that detects at least an acoustic wave from a subject;
an optical fiber that guides light emitted from a light source to a probe body; and
a light guide plate that guides light from a light entrance end to a light exit end, the light entrance end being optically coupled to the optical fiber and the light exit end being located in the vicinity of the acoustic wave detector,
wherein the light guide plate is secured in the probe body with a securing material provided at least partially around the light guide plate,
the probe comprises a surface that faces the subject during use, and
at least one layer of air is provided between the light guide plate and a side surface of the acoustic wave detector, the layer of air extending from the surface of the probe body toward the interior of the probe body and being open at the surface.
2. The probe as claimed in claim 1 , wherein the light guide plate is disposed on each of opposite sides of the acoustic wave detector such that the acoustic wave detector is positioned between the light guide plates.
3. The probe as claimed in claim 1 , wherein the light guide plate is secured in the probe body with a securing material provided at least partially around the light guide plate between the light entrance end and a position away from the light entrance end by a distance h.
4. The probe as claimed in claim 3 , wherein an area of the side surface other than an area corresponding to the distance h from the light entrance end of the light guide plate is covered with the layer of air.
5. The probe as claimed in claim 1 , wherein the light guide plate is at least partially made of glass.
6. The probe as claimed in claim 1 , wherein the securing material is made of a fluorine resin material.
7. The probe as claimed in claim 6 , wherein the securing material is made of tetrafluoroethylene-perfluorodioxole copolymer.
8. The probe as claimed in claim 1 , wherein the securing material is made of a fluorosilicone rubber.
9. The probe as claimed in claim 1 , wherein the securing material is made of a low-refractive index silicone resin or a methyl silicone resin having a refractive index lower than the refractive index of the light guide plate.
10. The probe as claimed in claim 1 , wherein the securing material is provided to extend over at least ⅓ of a distance between the light entrance end and the light exit end.
11. The probe as claimed in claim 1 , wherein the securing material is provided between the light guide plate and a case forming the probe body or a case provided in the probe body.
12. The probe as claimed in claim 1 , wherein the light guide plate is secured with the securing member between a case forming the probe body or a case provided in the probe body and a holding member that holds the acoustic wave detector.
13. The probe as claimed in claim 12 , wherein the acoustic wave detector is attached to the holding member after the light guide plate is secured with the securing member.