| 摘要 |
PURPOSE:To improve the rate of light condensation at a light projection terminal by forming a part which while increasing in numerical aperture, decreases in core diameter successively, or vice versa to prescribed lengthwise length. CONSTITUTION:The numerical aperture of a core 3' near the light projection part is equal to that of the core of an optical transmission part at a position B' and decreases successively in a direction B'B and becomes equal to that of the light projection terminal 5 at a part 4. Consequently, the radiation angle of light power emitted from the light projection part 5 is less than that of the other light projection part corresponding to the numerical aperture of the core. Consequently, no expensive condenser lens is interposed between the light projection terminal 5 and an object of irradiation and even when the interval between both is reduced greatly, the diameter of an irradiation spot decreases to improve the efficiency of light condensation to the object of irradiation. |
