| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a light-emitting device, which has a Fresnel lens and a light source in a case, capable of easily attaining desired radiation angle characteristics of the Fresnel lens and transmitting heat generated from the light source to the case at high efficiency and being utilized at a deep area in the water. <P>SOLUTION: The light-emitting device 1 includes the case 2 having a light transmission section 2a and internally sealing insulating liquid 5, the light source 3 arranged in the case 2 and immersed in the liquid 5, and the Fresnel lens 4 arranged in the case 2 and immersed in the liquid 5 and changing a radiation angle of light incident from the light source 3 through the liquid 5 and emitting the light with its radiation angle changed to the outside through the light transmission section 2a. The Fresnel lens 4 has a sheet-shaped lens body 41 wherein a Fresnel lens formation section 41a is formed on one surface, and a sheet-shaped lid body 42 superposed on the one surface side of the lens body 41 and sealing a gaseous body between the Fresnel lens formation section 41a. <P>COPYRIGHT: (C)2012,JPO&INPIT |
