High-precision aspherical parts can be produced by polishing (grinding) methods that control the thickness of removal , namely plastic injection molding and glass compression molding technology, this technology can make a part of aspheric lens. Plastic lens injection molding is a processing method in which molten resin is injected into a mold, and pressure is applied while cooling and solidifying. This method can be inexpensive and mass-produced, but there are some problems with the plastic itself, such as temperature changes and moisture absorption. Changes in the refractive index of a lens.
Compression molding of glass is the best method for mass production of small parts instead of cutting, grinding, and grinding lenses and prisms. The molding technology is to control the temperature in the mold to be above the glass transition temperature of the stamping and below the softening temperature. In the mold, enter the glass with fluidity, press and form, and keep this state for more than 20s until the formed glass is formed. The temperature distribution is uniform, the shape accuracy of the mold is made 0.1 μm, and the surface roughness is made below 0.01 μm. Under the above conditions, pressure forming can process parts with similar accuracy to the mold.
