Papers by Keyword: Optical System

Abstract: Optical system is important and optimized for highly spatial resolution in certain wavelength bandwidth. We tested three small refractor telescopes with different aperture (two telescopes with 80 mm in diameter and one with 66 mm diameter) and focal-length (544 mm, 400 mm, and 389 mm, respectively) in order to know the resolution from visual to near infra red regions. The images of sinusoidal bar test chart were recorded from CCD detector. The reference filter of Sloan Digital Sky Survey (SDSS) is also attached in front of detector. The filters have the range of G (401-550 nm), R (555-695 nm), I (690-820 nm), Z (>820 nm), Z_s (826-920 nm), and Y (950-1058 nm). The last filter is referred to the limit of quantum efficiency of the detector. The maximum frequency for each pixel from each Modulation Transfer Function (MTF) was performed. We found that smaller diameter telescope is better resolution in the visual wavelength than the wider diameter and longer focal-length. In the near infra red region, the opposite results were obtained. The coating lens quality may affect the wavelength dependences. This study has advantages of selecting low cost and high resolution optical system for different applications, e.g. very young crescent moon observation, etc.

Abstract: Discussed the use and application prospects of the solar simulator, we design a complete solar simulator experiment platform, the simulator contain the optical system, air-cooled system, the mechanical structure and control system. The significance of this paper is to propose a new method for the design of the steady-state solar simulator, which is able to complete a seamless connection with a lot of laboratory equipment and has played an active meaning for the development of the application of solar energy industry .

Abstract: The electrowetting effect is one physical chemistry phenomenon, it through adds certain external voltage in the solid - liquid contact surface to change the liquid to the solid moist degree, thus changing the contact angle of liquids and solids. In this article double liquid zoom lens are based on this kind of electrowetting effect. Optics focal variation system realizes the focal variation to satisfy two basic conditions[2]: (1) changing the focal distance; (2) maintaining the image plane position invariance. The single liquid zoom lens cannot maintain the position of the image formation surface invariance, this article takes on the electrowetting effect double liquid zoom lens as a foundation, and designs to realize new optical systems without mechanical movement focal variation using the motor control, and through MATLAB software simulation inferential reasoning the result.

Abstract: Design of off-axis system is a hot and difficult topic in optical design area. The wide field of view(WFOV) off-axis system this paper involved always have the drawbacks of complicated large size and great weight. This paper introduces an application of free-form surface(FFS) in WFOV off-axis optical system design, analyzes FFS optics’ material and fabrication methods. The system uses one FFS lens and one doublet, image quality meets the design specification, and characterizes by simple structure and lightweight.

Abstract: Presently for single function and high cost of the phototherapy equipments, this paper introduces a kind of Double-Wave-Bands therapeutic apparatus, which fully utilizes the principle of near-infrared wavelengths treating various pains and UVC sterilizing. This apparatus uses two different kinds of wave bands by selecting different light sources, but a set of control system. Because of a machine with multi-purpose and less cost, this apparatus can treat all forms of disease safely and effectively through using output light of the optical system by various forms of curing probes to be helpful for a promotion.

Abstract: To meet the demand of large displacement measurement instrument with nanometer precision, this paper introduces the metrological grating with the nanometer measurement precision and large displacement, based on two times' Moiré fringe principle. Its basic principle is that two indicated gratings are fixed on the same measuring base scale, when they move relatively to the scale grating, two groups of one time Moiré fringe will be produced, then two groups of lens are adopted to make the fringe move oppositely, at last the two times Moiré fringe will be produced through interference on the photoelectronic receive element. By subdivision of the two times Moiré fringe, this system can achieve 2.70×10-10m measurement resolution. In addition, this paper also analyse the optics system and light source.

Abstract: In this study, the back-propagation neural network technology (BPN) is utilized to identify the shape of the defective solder ball of ball grid array (BGA) so as to promote the accuracy of the optical inspection and measurement. The two dimensional BGA optical inspecting system is implemented by Visual Basic as the developing tool incorporated with the Halcon’s function which is the database of the image processing on Windows operation system. For the development of the processing procedure of the automatic optical inspecting system, the precise geometrical information of the solder ball is evaluated by the sub-pixel method to identify the shape of solder ball and its location which are acquired to classify the defects of solder ball including the ball offset, the ball over scale, the ball absence, and the ball shape under the BGA board is offset and rotated at any angle. From the experimental results, the back-propagation neural network technology is proved to properly identify and classify the shape defects, especially for the ball deformation and the ball bridging of the solder ball which can achieve and contribute the requirements for the automatic inspection and the high identification efficiency.