At present, micro lens arrays have been widely used in the fields of infrared detection, light gathering, portable solar battery and so on. The focusing and imaging properties of micro lens arrays are closely related to the performance parameters such as point diffusion function, diffraction efficiency and optical intercept. In order to better evaluate the quality of micro lens, this paper introduces a method for accurately measuring the optical intercept of micro lens arrays, which is more precise and has less deviation than interferometry, CCD direct imaging and so on. This experiment is based on the principle of CCD imaging and image processing, and a set of testing system is established. The system is mainly composed of a laser light source, a collimation system, samples and a camera. After many experiments, The optical post intercept detection device can obtain test accuracy below 5μm
In this paper, the radial refractive index change of the grin lens is measured based on the principle of Mach-Zehnder interference. Using an image sensor to obtain experimentally detected images, the computer-derived interference pattern is subjected to grayscale stretching and filtering, and then the center position of the interference ring and the distance between the interference rings are determined to obtain the refraction of the grin lens. The rate changes. Through experiments, the actual samples of different thicknesses were tested, and the measurement accuracy can reach 10-4.
In order to meet the increasing demand for the diagnosis of household medical eye fundus, the design of a new fundus camera is proposed. The entire structure includes the imaging system and the lighting system. The optical imaging system, modeled on the Kepler telescope, matches the exit pupil of the human eye and the entrance pupil of the mobile phone camera. Thus, this system uses a mobile camera lens that owns more than 5 million pixels to take a picture of a clear fundus. A new type of fundus camera is designed with the field of 40°, the working distance of 30mm and the full length of 138 mm. The value of MTF outweighs 0.5 at the central field of view. The lighting system takes advantage of the Kohler illumination. The stray light of the reflection of corneal is effectively suppressed by adding an annular aperture on the optical path. The inner diameter of the annular light spot formed at the cornea was larger than 4mm, the outer diameter was less than 6mm, and the diameter of the evenly illuminated fundus area was 12mm.
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