| 摘要 |
An illumination unit for an endoscope, which does not increase in diameter and has high emission intensity, is provided. The illumination unit includes a protective cover 11, a sleeve, a fluorescent body 13, a ferrule 15, and an optical fiber 16. A fluorescent body-holding portion 22 is formed at a tip of the ferrule 15, and a metal reflective film 14 is formed on an inner peripheral surface of the fluorescent body-holding portion 22. The fluorescent body 13 is irradiated with blue laser light emitted from a tip of the optical fiber 16 and the blue laser light and excitation light of the fluorescent body are mixed to each other, so that pseudo white light is obtained. When the fluorescent body 13 is formed in a substantially columnar shape, an emission diameter of the fluorescent body is denoted by D1, a thickness of the protective cover 11 is denoted by t1, and an effective diameter of the protective cover is denoted by D2, "0.7 mm‰¤D1‰¤0.9 mm", "0.4 mm‰¤t1‰¤0.59 mm", and "1.3 mm‰¤D2‰¤1.5 mm" are satisfied. It is possible to regulate the thickness t1 of the protective cover 11, which allows the illumination unit to be compact, and the emission diameter D1 of the fluorescent body 13 without the reduction of light emission efficiency. |
