Design of infrared optical system with super-long focal length and dual field-of-view

2014 ◽  
Vol 7 (4) ◽  
pp. 631-637
Author(s):  
白玉琢 BAI Yu-zhuo ◽  
木锐 MU Rui ◽  
马琳 MA Lin ◽  
贾钰超 JIA Yu-chao ◽  
普群雁 PU Qun-yan ◽  
...  
Keyword(s):  
Optical System ◽  
Focal Length ◽  
Field Of View

scholarly journals Catadioptric Optical System Design of 15-Magnitude Star Sensor with Large Entrance Pupil Diameter

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5501
Author(s):  
Yang Bai ◽  
Jianlin Li ◽  
Rongwei Zha ◽  
Ying Wang ◽  
Guangzhi Lei
Keyword(s):  
Optical System ◽  
Attitude Control ◽  
Pupil Diameter ◽  
Focal Length ◽  
Field Of View ◽  
Star Sensor ◽  
Spherical Lens ◽  
Entrance Pupil ◽  
Secondary Mirror ◽  
Entrance Pupil Diameter

The optical system is one of the core components for star sensors, whose imaging quality directly influences the performance of star sensors for star detection, thereby determining the attitude control accuracy of spacecrafts. Here, we report a new type of optical system with a catadioptric structure and a large entrance pupil diameter for a 15-magnitude star sensor. It consists of an improved Cassegrain system (R-C system), an aperture correction spherical lens group and a field of view correction spherical lens group. By embedding the secondary mirror of the R-C system into the output surface of the negative spherical lens of the aperture correction spherical lens group, the blocking of incident light is eliminated from the secondary mirror holder. After the structure optimization, the catadioptric optical system (COS) had a spectral range of 450 nm–950 nm, an entrance pupil diameter of 250 mm, a half-diagonal field of view of 1.4° and a focal length of 390 mm. By using theoretical calculations and experimental measurements, it was verified that the COS, with the ability to correct astigmatism, lateral color and distortion, can fulfill the detection of 15-magnitude dark stars.

scholarly journals A Novel Focal Length Measurement Method for Center-Obstructed Omni-Directional Reflective Optical Systems

2019 ◽  
Vol 9 (11) ◽  
pp. 2350 ◽  
Author(s):  
Hojong Choi ◽  
Joo-Youn Jo ◽  
Jae-Myung Ryu
Keyword(s):  
Optical System ◽  
Measurement Method ◽  
Focal Length ◽  
Tolerance Analysis ◽  
Field Of View ◽  
Optical Systems ◽  
Wide Field ◽  
Surveillance Camera ◽  
Length Measurements ◽  
Design Software

An omni-directional optical system can be used as a surveillance camera owing to its wide field angle. In cases in which a system is designed with a central screen obscuring structure to increase the resolution of the off-axis field, however, the conventional methods cannot be used to measure the effective focal length (EFL). We assumed the actual and theoretical distortion values of the fabricated optical system to be the same and determined the system’s EFL by finding the minimum deviation point of the measured and theoretical distortions. The feasibility of the determined EFL was verified through a tolerance analysis of the system. For these precise measurements we also analyzed the sources of error. To verify our proposed measurement method, we measured the focal length of a center-obstructed omni-directional reflective optical system with an 80–135° field of view (FOV). The EFL from the measurement was 0.3739 mm and was only approximately 11 µm different from the EFL calculated using the design software. Thus, the reliability of focal length measurements in omni-directional optical systems was improved.

Design of Athermalized Infrared Telephoto Lens

2013 ◽  
Vol 552 ◽  
pp. 8-13
Author(s):  
Yu Zhang ◽  
Ji Yang Shang ◽  
Yue Xu ◽  
Wen Sheng Wang
Keyword(s):  
Image Quality ◽  
Optical System ◽  
Power Distribution ◽  
Focal Length ◽  
Diffraction Limit ◽  
Field Of View ◽  
Optical Systems ◽  
Modulation Transfer ◽  
Full Field ◽  
Telephoto Lens

IR optical system is much more appropriate to be applied in cluttered and formidable conditions. The change of temperature could degrade image quality of the infrared optical system. So the athermalization becomes the difficult part and key factor in the designing of MWIR optical systems for working under temperature range of -40°C~60°C. In this paper, the infrared telephoto lens is designed; it meets the designing requirements and has good image quality. The effective focal length is 240mm and the F-number is 2.The full field of view is 3.2°. In order to balance the chromatic aberration, an aspherical surface is used in the athermalized infrared optical system. Through carefully selected optical material and reasonable optical power distribution, passive optical athermalization can be realized. The curve of MTF is close to diffraction limit. Within the working temperature, the value of MTF at 30cy/mm is always large than 0.6. The results show that the modulation transfer function (MTF) of optical system in all field of view approaches the diffraction limit at different temperature, and 80% energy concentrates in 1 pixel.

Design of Reflective/Diffractive Objective Optical System for Handed Low-Light Night Vision Google

2014 ◽  
Vol 597 ◽  
pp. 439-443
Author(s):  
Ning Li ◽  
Rui Lan Zhang
Keyword(s):  
Image Quality ◽  
Optical System ◽  
Focal Length ◽  
Optical Element ◽  
Night Vision ◽  
Field Of View ◽  
Improved Method ◽  
Low Light ◽  
High Image Quality ◽  
Aberration Theory

For the design direction of low-light night vision goggle become more and more miniaturization and high image quality [1], this artical design a reflective/diffractive objective optical system with optical software ZEMAX. It combines diffractive elements with reflective elements to design a reflective/diffractive objective with a 14.5° field of view and a 1.0/1.2 relative aperture and a 95mm focal length , and it introduces an improved method based on primary aberration theory in reflective/diffractive hybrid optical system. Etching diffractive optical element on the mirror can be usful for correcting aberration and improving the image quality.

A High Resolution Scanning Microscope

1968 ◽  
Vol 26 ◽  
pp. 356-357
Author(s):  
A. V. Crewe ◽  
J. Wall ◽  
L. M. Welter
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
Spherical Aberration ◽  
Focal Length ◽  
Spot Size ◽  
Emission Source ◽  
Field Of View ◽  
Scanning Microscope ◽  
Magnetic Lens ◽  
High Quality

A scanning microscope using a field emission source has been described elsewhere. This microscope has now been improved by replacing the single magnetic lens with a high quality lens of the type described by Ruska. This lens has a focal length of 1 mm and a spherical aberration coefficient of 0.5 mm. The final spot size, and therefore the microscope resolution, is limited by the aberration of this lens to about 6 Å.The lens has been constructed very carefully, maintaining a tolerance of + 1 μ on all critical surfaces. The gun is prealigned on the lens to form a compact unit. The only mechanical adjustments are those which control the specimen and the tip positions. The microscope can be used in two modes. With the lens off and the gun focused on the specimen, the resolution is 250 Å over an undistorted field of view of 2 mm. With the lens on,the resolution is 20 Å or better over a field of view of 40 microns. The magnification can be accurately varied by attenuating the raster current.

scholarly journals Wide field-of-view crossed Dragone optical system using anamorphic aspherical surfaces

2018 ◽  
Vol 57 (15) ◽  
pp. 4171 ◽  
Author(s):  
Shingo Kashima ◽  
Masashi Hazumi ◽  
Hiroaki Imada ◽  
Nobuhiko Katayama ◽  
Tomotake Matsumura ◽  
...  
Keyword(s):  
Optical System ◽  
Field Of View ◽  
Wide Field ◽  
Wide Field Of View
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