AIR INJECTION UNIT FOR PROTECTING LENS IN OPTICAL METER HAVING PROTECTIVE CAP

摘要

PURPOSE: An air injection unit for protecting a lens in an optical meter having a protective cap is provided to prevent an adhering phenomenon of particles on a surface of a lens or a surface of a protective glass by removing the air from a front face of the lens or a front face of the protective glass. CONSTITUTION: An air injection unit includes a tube(101) and a cap(300) in order to remove alien substances from a traveling path of light. The tube is used for transmitting the light. The tube is surrounded by the cap. The cap is used for protecting the tube from an external shock. A front end portion of the cap has an inclined section. The length of the cap is relatively longer than the length of the tube. A cap flange is formed at a rear end of the cap. A tube flange having plural through-holes is formed at a rear end of the tube. A predetermined interval is formed between the tube and cap since a flange of the air injection unit is combined with the through-holes of the inside of the tube flange and the cap flange is combined with the through-holes of the outside of the tube flange.