| dc.description.abstract | Lens manufacturing assembly tolerance is a necessary issue for every lens optical factory, but its processing cost and optical imaging quality vary greatly from one optical factory to another with different technologies. This paper is analysis of glass lens material characteristics and lens manufacturing and lens assembly tolerances on its lens imaging quality.
This paper first analyzes the relationship between refractive index and wavelength of glass lenses, the chemical properties of glass and the relative price, and the price of the material should be considered when designing, so that a cheap lens with good imaging quality can be designed, because aspheric glass lenses will be used, so glass materials with a Tg value less than 550C should be used.
Because the design should not only consider the room temperature environment, but also consider the effect of temperature change, and analyze the relationship between the refractive index of glass and temperature changes. The temperature change and thermal expansion coefficient will affect the lens parameters. Different lens materials have different thermal expansion coefficients. After the temperature changes, the lens parameters will change, such as the radius of curvature, lens thickness, air gap and aspheric coefficient. The relationship between the optical power of the lens and the temperature, the refractive index of the lens can be compensated by the thermal expansion coefficient of the lens barrel material or the thermal expansion coefficient of different lens materials, and finally achieve the purpose of heat dissipation.
Optical distortion in the half-view angle θ approximation 90, tan90=, then the paraxial image height is infinite, but the real image height can not be infinite, if the lens optimization design process, optical distortion or the ideal image height as the target value, then the real image height in the half-view angle between 75 and 90, the real image height can not increase sharply, so the real image height will become a certain value, the image will overlap together. In order to change this situation, the definition of ideal image height needs to be changed, so that the ideal image height becomes a linear change, so in the design of large angle or wide-angle lens design, in order to avoid this shortcoming to use F-theta distortion to determine the degree of distortion of the imaging surface. And the human eye is sensitive to changes in light, the human eye will notice the difference between the brightness of the center of the picture and the edge, so the design should consider the relative illumination.
There will be tolerances during manufacturing and assembly, and tolerances will degrade the imaging quality of the designed optical system. Components with smaller tolerances mean more difficult manufacturing and higher prices, increasing cost pressure and manufacturing difficulty. Therefore, in the tolerance setting of the components, the tolerance range should be enlarged without sacrificing too much lens quality. This will not only reduce the cost, but also make it easier to manufacture. Finally, analyze the tolerance analysis in CODE V to calculate the cumulative probability function distribution of the lens manufacturing yield. The probability used by CODE V is the probability distribution of 2σ, which means that the system manufactured with a 97.7% probability will have this performance.
Finally, apply these theories to the design of the scanner lens, the optical path design of the Blu-ray optical read-write head, the design of the 2 million pixels mobile phone lens, and the design of the wide-angle lens of the monitor. The design must achieve its own design goals.
| en_US |