1. Precision glass molding
Precision glass molding is to heat the glass material to a high temperature to become plastic, shaping it through an aspheric mold, and then gradually cool it to room temperature. Precision glass molding is not suitable for aspheric lenses with a diameter greater than 10mm. However, new tools, optical glass and measurement processes are all driving the development of this technology.
2. Precision polishing and molding
Grinding and polishing are generally suitable for the production of a single aspheric lens at a time. With the improvement of technology, its accuracy is getting higher and higher. Most notably, precision polishing is controlled by a computer and automatically adjusted to achieve parameter optimization. If higher quality polishing is required, magnetorheological polishing will be used. Compared with standard polishing, magnetorheological polishing has better performance and shorter time.
3. Mixed molding
Hybrid molding, using a spherical lens as a base, die casting on the surface of the spherical lens through an aspheric mold, and curing an aspheric body with a layer of high molecular polymer by ultraviolet light. Hybrid molding generally uses achromatic spherical lens as the base, and a layer of aspheric surface is die-casted on the surface to eliminate chromatic aberration and spherical aberration at the same time. Hybrid molding aspheric lens is suitable for the occasions that require additional features (elimination of chromatic aberration and spherical aberration at the same time) and mass production.
4. Injection molding
In addition to glass aspheric lenses, there are also plastic aspheric lenses. Plastic molding is to inject molten plastic into an aspheric mold. Compared with glass, plastic has poor thermal stability and compression resistance, and requires special treatment to obtain similar aspheric lenses. However, the biggest characteristics of plastic aspheric lenses are low cost, light weight, and easy molding. They are widely used in occasions with moderate optical quality, insensitive thermal stability, and low pressure resistance.