| 摘要 |
PURPOSE:To obtain a normal distribution illumination whose incident light quantity loss is small by providing an uneven part having surface roughness of a prescribed range on the incident end of an optical fiber or an optical fiber bundle. CONSTITUTION:A very small uneven part which has been formed by an abrasive corresponding to #800-#2000 prescribed by JIS R 6001, or that which is equal thereto is provided on the incident end face of a multi-mode optical fiber whose light receiving angle is large, or an optical fiber bundle which had bundled these optical fibers. Accordingly, a light beam from a light source 5, which is made incident on the incident end of the optical fiber or the optical fiber bundle 8 comes into collision with an uneven part of the end face and the incident angle is diversified. In such a way, a mode which is propagated in the optical fiber is equalized extending from '0'-order to the maximum higher mode, and the emitted light becomes illuminating light whose intensity distribution is similar to a normal distribution. |
