| 摘要 |
PROBLEM TO BE SOLVED: To effectively evade troubles such as that an image forming lens and a cylindrical lens are contaminated, and heat distortion occurs, etc., by revising a flow path so that an air flow flowing out from a cover member does not strike the image forming lens. SOLUTION: A guide member 11 being a flow path revision means revising the flow path of the air flow is provided between the window 6a of the cover member 6 and the image forming lens 4a so that the air flow flowing out from the window 6a flows while avoiding the image forming lens 4a. This guide member 11 is erected on a bottom wall of an optical box 10, and is projected between the cover member 6 and the image forming lens 4a from its bottom surface. Then, since the air flow flowing out from the window 6a of the cover member 6 is bent as shown by the arrows A1 , A2 , the matter that the air flow strikes hard the image forming lens 4a is eliminated. In such a manner, only by providing a simple projection part (guide member) 11 on the bottom wall of the optical box 10, the contamination of the image forming lens 4a is evaded, and the clear image is kept for a long term. |
