| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical fiber unit which prevents biases of light receiving optical fibers arranged on a concentric circle around a light projecting optical fiber, improves the sensitive performance of a small diameter object, reduces a bending radius and is excellent in bending resistance. SOLUTION: The optical fiber unit is composed of a sensor head 3, the light projecting optical fiber 1, the light receiving optical fibers 2 and dummy threads 4. The light receiving fibers 2 and the dummy threads 4 are alternately arranged on and fixed to the concentric circle around the light projecting optical fiber 1 at nearly equal intervals within the same bore diameter of the sensor head 3. |
