Aspheric lens has better radius of curvature and can maintain good aberration correction to obtain the desired performance.The application of aspheric lens brings excellent sharpness and higher resolution, while the miniaturization of the lens is possible.
Aspheric lens, the radius of curvature varies with the center axis, to improve optical quality, reduce optical elements, reduce the design cost.Aspherical lens has unique advantages over spherical lens, so it has been widely used in optical instrument, image and optoelectronic industry, such as digital camera, CD player and high-end microscopic instrument.
A precision glass molding
Precision glass molding is to heat the glass material to a high temperature to become plastic, through the aspheric mold to shape, and then gradually cool to room temperature.At present, precision glass molding is not suitable for aspheric lens with diameter greater than 10mm.But new tools, optical glass and metering processes are all driving the technology.Precision glass molding, although at the beginning of the design cost is high (high precision mold development), but after mold molding, the production of high quality products can be amortized out of the early development cost, especially suitable for mass production occasions.
B. Precision polishing
Grinding and polishing are generally suitable for producing single aspheric lens at one time.Most notably, precision polishing is controlled by a computer and automatically adjusted to optimize parameters.If higher quality polishing is required, the magneto-rheological inspector will be used.Compared with standard polishing, magnetorheological polishing has higher performance and shorter time.Precision polishing, which requires professional equipment, is currently the first choice for sample making and small batch samples.
C mixed forming
An aspherical body with a spherical lens as the substrate, die-cast on the surface of the spherical lens by an aspherical mold and a layer of molecular polymer on the surface of the spherical lens by ultraviolet curing.Mixed forming, generally using achromatic spherical lens as the base, the surface die-cast a layer of aspheric surface, in order to achieve the simultaneous elimination of chromatic aberration and spherical aberration.FIG. 7 shows the manufacturing process of hybrid aspheric lens.Hybrid aspheric lens, suitable for mass production where additional characteristics are required to eliminate both chromatic aberration and spherical aberration.
D injection molding
In addition to the glass aspherical lens, there are also plastic aspherical lenses.Plastic molding is the injection of molten plastic into an aspheric mold.Compared with glass, plastic has poor thermal stability and compressive resistance, and special treatment is needed to obtain a similar aspheric lens.However, the biggest characteristic of plastic aspheric lens is low cost, light weight, easy to shape, widely used in moderate optical quality, thermal stability is not sensitive, resistance to pressure is not big occasions.
Each type of aspheric lens has its own comparative advantage.Therefore, for different applications, the selection of the right product is very important.Major considerations include: volume, quality, and cost.
A precision glass-formed aspherical lens, characterized by mass production and high thermal stability, is suitable for large batch, high quality and high thermal stability occasions
B. Precision polishing forming aspheric lens, with the characteristics of short sample making period and no need of mold, is suitable for sample making and small-batch sample making occasions
C hybrid aspheric lens, with spherical aberration and chromatic aberration calibration characteristics, suitable for wide spectrum, large batch, high quality occasions
D plastic shaped aspheric lens, with low cost and light weight, suitable for large batch, moderate quality, thermal stability is not high occasions
When the aspheric lens needs to be customized (no standard products or insufficient products in stock), development cost, sample cost, mass price, delivery cycle and other factors should be taken into account.