First, the camera lens
The optical characteristics of the photographic lens can be represented by three parameters, namely the focal length f' of the photographic lens, the relative aperture D/f' and the angle of view 2ω'.
If you do not consider the effects of various lens transmittance differences, no matter how long the focal length of the lens, and regardless of the diameter of the lens aperture, as long as the aperture value is the same, their luminous flux is the same as the lens design. For the camera lens, the F number is a particularly important parameter, and the smaller the F number, the wider the range of the lens.
Compared with the visual optical system, the photographic objective lens has both a large relative aperture and a large field of view. Therefore, in order to make the entire image surface clear and similar to the object plane, almost all seven aberrations are corrected. The resolution of the photographic objective is a comprehensive reflection of the relative aperture and the residual amount of the aberration. After the relative aperture is determined, an optimal aberration correction scheme that satisfies both the use requirements and is easy to implement is developed. For the sake of convenience, the "diffusion circle radius" is often used to measure the size of the aberration, and finally the optical transfer function is used to evaluate the image quality.
Second, the projection lens
The projection objective is to make the illuminated object into a bright and clear real image on the screen. Generally speaking, the image is much larger than the focal length, so the object plane is near the outside of the focal plane of the projection objective. The magnification of the projection objective is an important parameter for measurement accuracy, aperture size, viewing range, and structural size. The larger the magnification, the higher the measurement accuracy and the larger the aperture of the objective lens. When the working distance is constant, the larger the magnification, the larger the conjugate distance, and the larger the structure size of the projection system. Since it is amplifying, it can be known from the optical knowledge that the image center illuminance is proportional to the square of the relative aperture, and the method of increasing the relative aperture can be used to increase the image illuminance. The difference between a projection lens used on a liquid crystal projector and a conventional projection objective:
1. The relative aperture optical lens is larger.
2. Long distances, that is, need to be designed as a near-distance heart-light path.
3. Long working distance.
4. High resolution.
BRD is a China supplier of Dielectrinic Mirror. We have a high-tech work shop. We have a complete quality management system. Choose Customized Optical Components Supplier, you can be get most careful and thoughtful service!