A Design of Elastic Coating Fixture for Full Pass Hemispherical Lens
In the optical industry,when some lenses require coating with 100%effective through-hole,the processing process of coating first and then grinding the edges is often used.However,some film systems may damage the film layer when using the coating first and then edge grinding process,and this processing process is not applicable when the convex surface is close to the hemisphere(D(spherical aperture)/R(curvature radius)>1.6)of the lens,and there is not much margin(<0.3 mm)on the outer diameter.And the qualification rate is low.Therefore,it is necessary to design a fully transparent hemispherical lens elastic coating fixture to solve this problem,so as to achieve 100%effective aperture for lens coating.The fixture is made of elastic steel and uses a clamping method for the outer diameter of the lens and an elastic structure to compensate for the thermal expansion and contraction of the lens and fixture.The lens can be installed on the fixture for super washing and directly coated,without the need for a secondary hanging plate and a dedicated super washing fixture.The experimental results show that after using the coating fixture for coating,the effective aperture of the lens coating can reach 100%,and there will be no phenomena such as cracking,edge collapse,and surface indentation,and the film color is uniform and consistent.The fixture design is reasonable,the manufacturing process is simple,and the cost is low.This paper briefly describes the design and experimental results of an all pass hemispherical elastic fixture.