Optical Design and Fabrication|14 Article(s)
Study on Bessel Lens for Picosecond Laser Cutting
Zhang-fan WEI, Chuan SUN, Kai GUO, Ming CHEN, Li-hua HUANG, Ai-jun ZENG, and Hui-jie HUANG
A Bessel lens for laser cutting and beam measurement system are designed and developed. Additionally, picosecond Bessel beam is generated by a picosecond pulse laser and the designed Bessel lens, and it is used for the cutting experiment on a piece of silicate glass with the thickness of 1 mm. The results show that, by the incidence of a Gaussian beam with certain diameter on the Bessel lens, the central core diameter and non-diffracting propagation distance of the generated Bessel beam are 3.4 μm and 2.46 mm, respectively. In the cutting experiment, the diameters of the surface micro-holes before glass breaking are smaller than the designed central core diameter of Bessel beam. The designed Bessel lens and beam measurement system in this paper can satisfy the application requirements of laser cutting.
Acta Photonica Sinica
  • Publication Date: Oct. 15, 2020
  • Vol. 49 Issue 10 1022001 (2020)
An X-ray Detection Technology with Multi-curvature Bent Crystal
Jun SHI, Miao LI, Lin-dong-ying LUO, Feng WANG, Guo-hong YANG, and Min-xi WEI
In the spectrum diagnostic physics experiment of inertial confinement fusion, the spectral signal is weak due to the X-ray diffraction efficiency with crystal. So a spectral diagnostic instrument with high light collection efficiency and wide spectral range is urgently needed. A multi-curvature bent crystal multi-energy point imaging technique is proposed based on traditional conical crystal structure. It has the characteristics of wide spectral range, strong focusing ability and high spectral resolution. At the same time, it can eliminate imaging aberration in principle due to the rotational symmetry of imaging light. The measuring spectra experiment of multi-curvature bent α-quartz crystal is conducted at a Ti X-ray tube device and the same experiment with plane α-quartz crystal is done to demonstrate the strong focusing ability. The result shows that the intensity of multi-curvature bent α-quartz crystal is 100 times than that of plane crystal, and the energy range of detected X-ray is 4.51~5.14 keV. This device combined with a streak camera at a vertical direction could be used to collect weak X-ray with wide spectral range.
Acta Photonica Sinica
  • Publication Date: Mar. 25, 2020
  • Vol. 49 Issue 3 0322001 (2020)
Optical Design and Tolerance Analysis of Freeform Automotive Head-up Display
Yang-liu ZHANG, Zhou-ping SU, Hong-xiang PAN, Xing-tao CHEN, and Wen-yu ZHANG
A freeform optical system of automotive Head-Up Display (HUD) was designed. In the initial layout design of the HUD optical system, the sample points on two optical freeform surfaces of the HUD optical system are calculated by the seed curve extension algorithm. And the two freeform surfaces are expressed by the extended polynomials. Then the ray tracing is performed for the initial layout of the HUD optical system at center field of view with 0.5 mm ray sampling interval. The results show that the performance of the initial layout of the HUD optical system is the diffraction-limited, which can be used as the starting point for further optimization at full field of view. After optimization, the final HUD optical system is obtained. In order to simulate the observation of human eyes, several test points in the Eyebox are taken as object points, which are imaged on the image plane by the HUD optical system. The modulation transfer function plots of the several test points are greater than 0.5 at 6 lp/mm, which are close to diffraction limit. And the distortions of the final HUD system are less than 2%. Finally, the manufacture tolerances of two optical freeform surfaces are analyzed. The results show that the modulation transfer function plots of the HUD optical system are higher than 0.3 with the tolerance PV values of 0.42 μm and 0.62 μm of the two optical freeform surfaces respectively. For the current machining capacity, the tolerance requirements are reasonable.
Acta Photonica Sinica
  • Publication Date: Sep. 01, 2020
  • Vol. 49 Issue 9 0922002 (2020)
Multi-axis Focusing Lens Design for Precise Assembly of High-resolution Mobile Phone Lens
Fanghan CHEN, Guangyu ZHAO, Xiaomei ZHANG, Shilong JIANG, and Zhigang WEN
In the manufacturing process of high-resolution mobile phone lens consisted of glass and plastic material, many problems of assembly between glass lens and plastic lens group were existed such as sensitive to position change, low efficiency and low yield. The optimal proposal based on multi-point infinite conjugation modulation transfer function measurement was adopted to lens alignment and assembly in real-time feedback. As a critical imaging component of chart acquisition for modulation transfer function calculation, performance of multi-axis focusing lens played a significant role in guaranteeing measurement accuracy. The relationship between the design parameters of multi-axis focusing lens and the optical parameters of mobile phone lens to be assembled was established. Multi-configuration setting and aberration optimization of multi-axis focusing optical system were realized by ZEMAX simulation software. Simulation results showed that the size of focusing lens was compact, and both its tangential and sagittal modulation transfer function curves were nearly coincided with diffraction limit. The designed multi-axis focusing lens theoretically could be flexibly exploited to multi-point modulation transfer function measurement and precise assembly of high-resolution mobile phone lens up to 48 megapixel, which maximum full field of view angle reached 106°.
Acta Photonica Sinica
  • Publication Date: Dec. 25, 2021
  • Vol. 50 Issue 12 1222001 (2021)
Design and Test of Thermo Electric Cooling System for Space Based Telescope Detector Assembly
Wen-gang YANG, Xue-wu FAN, Chen-jie WANG, De-jin QIN, Bao-peng LI, Yun-fei DU, Liang-jie FENG, Hui ZHAO, and Wei GAO
Active cooling must be utilized to meet the need for the space-based telescope which need very low detector noise level. The precise thermal control measures based on thermo-electric cooling technique are utilized and especially the package system and heat rejection system of thermo-electric coolers and its cotroller system are designed respectively. The parasitic heat load to the detector and the heat path resistances are optimized to reduce the input power and the radiator size. Based on the Peltier effect and Joule effect and Frourie effect, the relations between the enviroments parameters and working parameters are analyzed. The enviroments parameters include the heat pumped requirements, the thermal resistance between the hot side and the sink and the hot side sink temperature, while the working parameters include the current, voltage and input power of coolers. The sensitivity between the heat loads, thermal resistance and the input power are especially researched. The qualification model of the telescope is developed and the thermal vaccum and balance test are accomplished. The test results show that the system design are appropriate and effective, the detector temperature is controlled at -75±0.2℃. Based on the test environments conditions and the cooler's working parameters, the thermal analysis model are discussed and corrected.These lessons can provide some reference for the development of thermo-electric cooling system of the similar space based telescope.
Acta Photonica Sinica
  • Publication Date: Aug. 01, 2020
  • Vol. 49 Issue 8 0822001 (2020)
Optical System Design of Miniaturized Fundus Camera Based on Non-coaxial Array Illumination
Yan-xiong WU, Zhi-yuan GUO, Miao YU, and Li-ping WANG
The mathematical model of fundus imaging under the non-coaxial array illumination is established. A micro optical system of fundus camera is proposed by using the independent design method of illumination light path and imaging light path, which avoids the interference of human cornea and omental objective reflected light on the retina image in the traditional fundus camera. The design of 6-array ring light source illumination system is completed, which is only 17.9 mm in length and the effective illumination line field of fundus retina is not less than 12 mm. The secondary imaging design is adopted in the imaging optical system.The modulation transfer function is better than 0.2@91 lp/mm and the distortion is less than 5% with 75 mm length. The simulation and design results show that the optical system of the proposed fundus camera can effectively suppress the stray light in the optical path which is conducive to obtaining high contrast retinal image. The results can provide a design reference for the development of high image quality, miniaturization and low stray light fundus camera.
Acta Photonica Sinica
  • Publication Date: Aug. 01, 2020
  • Vol. 49 Issue 8 0822002 (2020)
Influence of Weight Function on Progressive Addition Lens Design
Jian-dong GAO, Hua-zhong XIANG, Nian-ning LI, Cheng WANG, Gang ZHENG, Song-lin ZHUANG, and Da-wei ZHANG
In order to study the influence of the weight distribution function on lens design, on the basis of constructing the minimization model, the spline interpolation method was used to process the weight function of the transition region, and three groups of weight distribution functions were designed to connect the high weight region and the low weight region. According to different weight distribution functions, the corresponding progressive addition lens was designed, and the simulation, machining and evaluation were carried out. The experimental results showed that the weight distribution matrix has an impact on the optical performance of the lens. The faster the weight changes in the transition region of the average curvature and the difference between the principal curvature of the surface, the better the optical performance of the lens. Therefore, using the weight function with fast change of transition region is beneficial to reduce the astigmatism around the lens and optimize the lens power and astigmatism distribution.
Acta Photonica Sinica
  • Publication Date: Sep. 01, 2020
  • Vol. 49 Issue 9 0922001 (2020)
Design Method of Solar Radiation Simulation Optical System with High Energy Utilization Rate
Fanlin MENG, Shi SU, Guoyu ZHANG, Jian ZHANG, Shi LIU, Gaofei SUN, and Haowen PENG
Aiming at the disadvantages of large-scale solar simulators in the past, such as complex structure, low energy utilization rate and poor uniformity, a design method of solar radiation simulation optical system with high energy utilization rate was proposed. The ellipsoid condenser was designed based on the luminous characteristics of the real xenon lamp. By adding a spherical reflector, the combined condenser system was used to improve the energy utilization rate. The optical integrator was designed according to the principle of pupil matching. The irradiation uniformity was improved by the edge elimination method. The simulation results suggest that the energy utilization rate of the combined condenser system is 21.2% higher than that of the single ellipsoid condenser. The irradiation uniformity of the edge elimination method is 4% higher than that of the edge compensation method. The experimental results suggest that the working distance is 20 m, irradiation surface diameter is Φ2 m, maximum irradiance is 1 363.1 W·m-2, non-uniformity is ±4.5%. It has realized large-area, high-energy utilization rate solar radiation simulation, which provided an advanced means for semi-physical simulation and testing of solar sensors in space field.
Acta Photonica Sinica
  • Publication Date: Dec. 25, 2021
  • Vol. 50 Issue 12 1222003 (2021)