ABOUT THE CHOICE OF THE INITIAL SIDE OF A SPHERICAL GLASS LENS PROCESSING

The article analyzes the choice of the initial side of a spherical glass lens processing. The analysis was carried out on the basis of a survey of employees of the optical shop and familiarization with the description of a typical technological process for manufacturing lenses at one of the instrument-making enterprises in Novosibirsk, as well as by a retro-review of technical publications on the manufacture of optical parts. Two schemes of decision-making about the initial side of spherical lens processing are revealed: selection (assignment) or calculation by formula. The results of the analysis are formulated and the tasks of further research are defined.

Effect of the Dimensions of Coplanar Inner Floating Ring Electrode on the Performance of Liquid Crystal Lenses

In this study, we mainly investigated the effect of the dimensions of a coplanar inner floating ring (CIFR) on the lens performance in CIFR–hole-patterned electrode liquid crystal lenses (HPELCLs) at 100 Hz of the electrical driving frequency. The operation and threshold voltages in CIFR–HPELCLs are approximately 76% compared with those of the conventional HPELCL. The diameter of the CIFR with 360 μm in relation to imaging capabilities and those of the conventional glass lens and HPELCL were analyzed via the modulation transfer function. The relative mechanisms of the CIFR dimensions and the lens performance were also examined. An electric circuit model was used to analyze and illustrate the experimental results.

Investigation on the Improvement of Surface Quality by the Magnetic Plate-Assisted Magnetic Abrasive Finishing Process

The traditional magnetic abrasive finishing (MAF) process, the magnetic flux density at the bottom of the magnetic pole is unevenly distributed, resulting in poor uniformity of the finished surface. Therefore, it is proposed to improve the surface quality by attaching a magnetic plate at the bottom of the workpiece to improve the magnetic field distribution. It is confirmed by simulation that the magnetic field distribution at the bottom of the magnetic pole is effectively improved after the magnetic plate is attached. It is proved through experiments that the magnetic plate-assisted MAF process can obtain a smoother surface. The experimental results show that the surface roughness of the glass lens improves from 246 nm Ra to 3 nm Ra through the magnetic plate-assisted MAF process within 45min.

A study of distortion correction algorithms based on aspheric fisheye lens design

A design method of aspheric fisheye lens has been proposed in this paper, based on the requirements of automobile surround view system. The study has designed a kind of ultra-wide-angle fisheye lens, which only consists of a spherical glass lens and three aspherical plastic lenses. The maximum diameter of imaging aperture is 15.3 mm; the working distance behind is 2.158 mm; the total length of system is 11.44 mm; the focal length is 0.97 mm; the viewing angle is 210°, and the modulation transfer function (MTF) curve is 0.35 at 60 lp/mm. Furthermore, a kind of a distortion correction algorithm for fisheye lens has been created, which calculates the position of the ideal image point with the actual image point and the obtained distortion curve and distortion model. The algorithm can correct the distorted image taken by a fisheye lens to an image without distortion, which is suitable for the human eye. The algorithm, which is simple and effective, has been applied to the automobile surround view system. It has been verified to be accurate and reasonable, after the comparison is made between the real image taken by a fisheye lens and the corrected image.