koda-bun
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@The above photograph is of a phenomenon known as gNewtonfs Rings.h Newtonfs Rings are concentric circles that can be observed when light is projected on two overlapping optical elements. They are generated by light that reflects off the two elements in the air space between them and interferes with itself. The phenomenon is named after Isaac Newton, the founder of classical mechanics who formulated the Law of Gravity and discovered the rings. If the two contacting optical elements are identically curved, air cannot get between them and the Newton Rings do not form. The greater the curved faces differ, the thicker the air space and the more rings are formed. The number of these Newton Rings can be used to verify the curvature precision of an optical element.

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@What is necessary here is a gtest plate glassh with the standard curvature of optical element. A test plate glass is made of transparent glass and its curved surface represents the standard profile of an optical elementfs surface. A very precise test plate glass is the key to making high quality optical products. @Since a typical optical elementfs profile is a section of a sphere, test plate glasses are categorized by radius or R. For example, R40 indicates a spherical surface with a radius of 40 mm; the higher the number, the more gradual the curvature; the lower the number, the sharper the curvature. A variety of test plate glasses are prepared in line with design specifications. Polished optical elements are compared against them to verify profile precision.

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@By enhancing curvature precision and working to keep the thickness within a roughly 2/100 mm tolerance, a transparent texture of the optical element is obtained. It is absolutely essential when polishing an optical element to the precise curvature with no distortions from the center to the edge that the diamond pellets be accurately arranged on the polishing plate. This job has no diagrams or guide tools. The only thing specified is the number of pellets that go on each plate. So, how is it done? First, you calmly place five pellets around the center. Then, you determine inside your head a formation of five areas that are evenly spaced apart in the radial direction and, in one quick swoop, fill in those areas. This particular approach is just one example. The most suitable method for arranging the pellets differs according to the size and profile of the polishing plate. So, like chess masters, polishing professionals have a large number of standard moves.

 

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