Optoelectronic Instruments is a comprehensive professional course for senior students majored in optical engineering and similar specialties. Due to the low lecturer/ student ratio, typically less than 1:100, most of the students gave up the chance of one-to-one communication with the lecturers even when they were confused about the principle or applications of the instruments. A smart phone App <i>Rain Classroom </i>associated with messaging App <i>Wechat</i> is introduced. It enables the lecturers to receive instant feedback from students through bullet screen, push preview and review materials and post in-class quiz. Investigation also shows that 76% of the students enjoyed the new interactive tool, acknowledging its help in understanding the topic better, improving in-class interaction, and after class communications.
When talking about higher education, it’s hard not to run into a discussion on what’s really better for student learning: online learning or traditional learning? Of course, the key is to offer both, and potentially emphasize blended learning as the less polarizing option. Online courses are much more flexible and less expensive, but powerless while hands-on practical capacity is involved. Traditional experimental course can maintain a fluid and solid learning process but is less productive due to its scheduled time and simplex access. In this paper, a buffet-style knowledge service mode applied in a 12-week-long project-based experimental course Optoelectronic Instrument Experiments (OIE) is discussed. Our purpose is to find a blended learning mode in experimental education.
Shipboard helicopter optical landing guidance system can ensure the safety of landing when the helicopter completed missions. Stray light has a great influence on positional accuracy of the optical landing guidance system. In order to improve the imaging quality of the optical system, the sources of stray light in optical landing guidance system were studied in this paper. Moreover, the effects of stray light on the system were analyzed in detail. The model of the optical landing guidance system was established in TracePro software. 16 different off-axis angles were selected to carry out the ray tracing. Through modeling and simulation, the irradiance of stray light in the imaging plane and the point source transmittance (PST) of the system were obtained; And they were used to evaluate the level of stray light. Results show that the PST of the optical landing guidance system can achieve a level of 10<sup>-5</sup>~10<sup>-8</sup> when the off-axis angle is equal to or greater than 49°. At the same time, the solar stray light energy that gets to image plane can achieve a level of 1×10<sup>-4</sup>W/m<sup>2</sup>. So the optical landing guidance system can work regularly in this range.
For the method that active optical system achieves zoom by changing the surface of deformable mirror, the design of the brake, the rationality of the layout and the actual change of the surface are very critical issues. This paper presents a practical research idea and method. The finite element model of a deformable mirror was established based on finite element analysis software, and the analysis is achieved after configuring the brake method that needed. The feasibility of the drive scheme is verified through comparing the simulation results and the ideal surface. On this basis, the preliminary design of the core components of piezoelectric ceramic driving circuit brake is achieved.
The paper describes how the pedagogy of project based learning (PBL) was integrated into the Optical System Design course at School of Opto-electronics of Beijing Institute of Technology, Beijing, China. The course teaching philosophy, implementation methodologies, examples and experiences were discussed.
Principle and Design of Optoelectronic Instruments (PDOI) is a comprehensive engineering course set in the fourth year in School of Optoelectronics, Beijing Institute of Technology, China. After three years of study, the students have acquired basic knowledge in optics, mechanics, electronics, and computer science. They are ready to make a comprehensive application of the knowledge they have learnt in something really important. Like most engineering courses, PDOI needs practical section to help students understand how theories work in engineering. Thanks to the China International Exhibition of Lasers, Optoelectronics and Photonics which is held annually in Beijing, it offers a good opportunity for undergraduates to see advanced instruments with their own eyes. It is a wonderful extracurricular practice for PDOI. In this paper, we will introduce the exhibition-involved curriculum design and give the initial results.
As a kind of light-weighted and convenient tool to achieve stereoscopic vision, virtual reality glasses are gaining more popularity nowadays. For these glasses, molded plastic lenses are often adopted to handle both the imaging property and the cost of massive production. However, the as-built performance of the glass depends on both the optical design and the injection molding process, and maintaining the profile of the lens during injection molding process presents particular challenges. In this paper, optical design is combined with processing simulation analysis to obtain a design result suitable for injection molding. Based on the design and analysis results, different experiments are done using high-quality equipment to optimize the process parameters of injection molding. Finally, a single concave-convex lens is designed with a field-of-view of 90° for the virtual reality 3D glasses. The as-built profile error of the glass lens is controlled within 5μm, which indicates that the designed shape of the lens is fairly realized and the designed optical performance can thus be achieved.
We present a high dynamic range (HDR) imaging system design scheme based on coded aperture technique. This
scheme can help us obtain HDR images which have extended depth of field. We adopt Sparse coding algorithm to
design coded patterns. Then we utilize the sensor unit to acquire coded images under different exposure settings. With
the guide of the multiple exposure parameters, a series of low dynamic range (LDR) coded images are reconstructed. We
use some existing algorithms to fuse and display a HDR image by those LDR images. We build an optical simulation
model and get some simulation images to verify the novel system.
Along with the development of semiconductor lighting technology, LED chip is widely used as the source of the glare
flashlight. Collimating the light of the source and improving the utilization rate of light energy is crucial. The collimating
lens is designed by the theory of geometrical optics and the theory of non-imaging optics. The small angle light from the
source is collimated through the collimating lens surface, and the large angle light is collimated by the total reflection of
the collimating lens. The collimating lens has a high light energy utilization and a good collimating performance. The
collimation system is simulated and optimized in the Lighttools software. When the size of the LED chip is 1 mm*1 mm,
the energy utilization rate of the collimating lens is more than 95%, and most lighting area radii are no more than 8 m
when the illuminated plane is 500 m away from the light source.
The influence of errors on the optical system’s image quality was theoretically investigated using error theory. The accuracy of surface figure fitting was researched. In this paper, we analyzed many sections that may cause error based on thermal analysis and mechanical analysis. We used error analysis to consider the accuracy of surface figure fitting. We took account of the error of ABAQUS modeling, initial error, error of surface figure fitting, error of MATLAB and the error of ZEMAX. We at last gained the total error, and analyzed which is the dominant error. The main result can be used to assess and correct the error of opto-mechanical-thermal, and provide support for Quadratic optimization design.
Illumination system is one of the most important parts of the micro-lithography object lens. Its performance can greatly
affect the lithography machine's etching graphic quality. In this paper, we discuss a DUV micro-lithography illumination
system which can achieve high uniformity and a large illuminated area on the mask. According to the large numerical
aperture requirement, a refractive illumination system is designed and optimized with software ZEMAX. The system
also meets the requirement of large illumination area on the mask, and no aspherical lens is used. Characters of different
illumination structures and modes are introduced here. Then by using the software of TracePro, illumination systems
with different kinds of aperture are modeling and illuminaces are analyzed. We research effect of illuminace on the mask
which bring by different kinds of aperture. Also in this paper, we make a study of relationship between different
illumination mode and different kinds of graphics. Finally, we compare the results and give suggestion about how to
choose illumination mode. That is meaningful for choosing different aperture in illumination system of microlithography.
For the precise alignment for the large aperture space optical systems, we report a feasible way of Computer-aided
alignment (CAA) in detail in this paper. Different CAA algorithms are introduced and we used two of them to do the
CAA simulation for a self-made coaxial three-mirror optical system. The methods of the wavefront detecting and object
source's providing have been put forward for the actual alignment. Based on these methods, CAA results are shown
using the sensitivity table algorithm and the merit function regression method respectively. Comparisons are made
between these two methods, and the results show that the merit function method shows higher accuracy when the initial misalignments are large.
Conformal domes are often deviated greatly from spherical surface descriptions, so severe aberrations which vary with
the field-of-regard (FOR) angle are introduced by the domes. Therefore dynamic correction is required. Two
counterrotating Risley prisms and two lenses are used to correct the dynamic aberrations. The inner surfaces of the
counterrotating prisms and the two lenses are described by Zernike Fringe polynomials. The scan of the field of regard is
achieved by counterrotating the Risley prisms about the optical axis. The performance after correction in terms of
Zernike aberrations and RMS spot size versus FOR angle is reported by an example. For comparison, the RMS spot
radius is reduced to 16-68 &mgr;m after the final correction, which is approximately 0.8-4.5 times Ariy spot radius, which is
much better than the 30.2-69.1 times in the baseline system. The design results show that the counterrotating wedges and
the two lenses which both have Zernike fringe sag inner surfaces are good correctors in conformal optical design.
In some applications the large field-of-view projector is demanded for special purpose. However, currently
available liquid-crystal-projectors generally have a field-of-view of 40 degree. These ordinary projectors can't meet
the special requirements. The ordinary method for solving the problem is to remove the original projection lens and
design a new fisheye lens whose field-of-view is large enough to meet the requirement. However, most current
advanced projector's lenses are integrated with the circuit controllers or circuit boards. In many situations it is
impossible to replace the lenses. In this paper, a new method, designing a new supplementary lens for the original
projector without destroying its structure, is presented. The field-of-view of the new system can be expanded to
180 degree. Since the exit beam of the original projector lens is similar to parallel beam, the entrance beam of the
supplementary lens is also parallel beam. That means, both the entrance and the exit beams of the supplementary
lens are parallel beams. So the supplementary lens can be treated as a telephoto system. In this paper, the focal
length of the original projector lens is 16.4 millimeter, the field-of-view is 42 degree, and the required field of view
is 180 degree. The new designed supplementary lens is a reverse Galilean telephoto system. The software Zemax is
used to design the system. Results show that the system is well designed and it can meet the actual requirements.
Computer-aided alignment (CAA) is a significant technique to correct errors which are caused by the misalignment of
each element in an optical system. It is especially important in such areas as space remote sensing optical systems, since
manual adjustment is impossible when it operates in orbit. In this paper, a three-mirror optical system is adopted as an
example to perform CAA. Principle of this system is introduced. And based on the CAA algorithm, the method of CAA
for the segmented mirror is expatiated in detail. A numerical simulation of CAA has been performed for the segmented
mirror to verify the ability and accuracy of the method. Comparisons of the image qualities between the pre-alignment
and post-alignment systems are also presented. These results indicate that the CAA method is feasible.
Star sensor is a special high accuracy photoelectric instrument. It is often used in navigation of aircraft, cruise missiles,
and ballistic missiles, so the imaging quality of the optical system in a star senor is very important. The spherical
windows with a small impact to imaging performance are usually used in traditional star sensors. However, the spherical
surfaces are not ideal aerodynamic surfaces and would cause problems such as high drag. In this paper the conformal
window whose outer shape is neither spherical nor flat is used in a star sensor. Unfortunately, the conformal shape
introduces amounts of aberration which may lead to low imaging resolution. The various correctors can be used to
eliminate the aberrations, for example, the fixed corrector, the arch, Zernike wedges, and the deformable mirror. The
fixed corrector method is selected to decrease aberrations from the conformal window in this paper. The surface of the
conformal window in the star senor is described as the Von Karman equation. The field of view is 17.6°×13.5°, and the
size of the CCD pixel is 6.45 um×6.45um. The optical design program ZEMAX is used to design this system. After the
optimization, under the max frequency of 77.52lp/mm, the MFT can almost achieve 30%. The design results show that
the aerodynamic requirements can be satisfied by the application of the conformal window in the star sensor, and the
aberrations can be corrected by proper ways.
A new method based on Dynamic Data Exchange (DDE) technology for computer-aided alignment is put forward in this
paper. It is adopted to realize the automatic data transferring between Matlab and Zemax optical software. Based on the
analysis of CAA and its procedure, a self-made program is developed to perform all the CAA steps under Matlab
environment. Flow process of this program is shown in this paper. A Gregorian system is adopted as an example to verify
the feasibility of the program. Comparisons of the image quality between the misaligned system and the post-aligned
system are presented. Results show that this program is very effective.
Computer-Aided Alignment (CAA) is an effective method for improving image quality of an optical system. This paper studies some key techniques of CAA for space telescope, including the mathematical model of CAA, the acquirement and processing of aberration data, the establishment of sensitivity matrix and the solution of misalignment. A numerical simulation of a space telescope has been performed to verify the ability and accuracy of the method.
A Very High Resolution Telescope (VHRT) is designed as a space-to-earth remote sensor and the polarization effect in this VHRT is analyzed in this paper. First, the theory of polarization effect is reviewed. Second, the Jones arithmetic of polarization aberrations in VHRT is presented. Then, CODE V software is used to realize the polarization ray trace in this system and the results of the polarization effect analysis are obtained. The output information includes the plot of Modulation Transfer Function (MTF), the plot of Point Spread Function (PSF), pupil map, relative illumination, illumination, distortion and Strehl ratio. Finally, effective methods to control the polarization effect in an optical system are given. According to the results of analysis, we have drawn the following conclusions. Polarization effect in an optical system shouldn't be ignored to improve the imaging quality; with the incident angle as small as possible to control the polarization effect. Coating design must be considered carefully for the optical design.
Thin-film-coated prisms are used widely in optical systems. This is because that they not only provide a convenient and efficient means of light-beam deviation, but also have special polarization properties. Polarization effect is one of the most important factors affecting the performance of optical systems. Thin-film-coated prisms play an important part in the optical systems because of their special polarization properties. In this paper polarization properties of thin-film-coated prisms are analyzed as general polarization elements and two examples are given. The polarization properties of the prisms mainly lie on the thin films coated on the interfaces. One example in this paper is the design of using a thin-film-coated totally reflecting corner prism to produce quarter-wave phase retardation. Another example is the design of using a thin-film-coated beamsplitter cube prism to cancel the unwanted polarization effect. According to the analysis of the polarization properties of thin-film-coated prisms, we can draw a conclusion that it is an effective method to use thin-film-coated prisms to get the desired polarization state or to control the polarization effect in optical systems. Furthermore, optical thin film system coated on optical interfaces has a profound effect on the polarization properties of optical elements. Therefore, optical thin film designs should be considered carefully while designing optical systems.
In order to get a simple LED illumination system with a short length, the LED needs a large irradiant angle (2ω = 90°) and the lens needs a large aperture. This would conduce a severe non-uniformity on the illuminated area and a very low F-number. So it is rather difficult to design a singlet lens for LED illumination system with a better uniformity in certain area because of the non-uniform irradiation of the LED and the contradiction between the focal length and the aperture. For an on-axial point source, the spherical aberrations in different apertures can change the propagating direction of the rays; therefore it is possible to get a uniform illumination with the help of spherical aberrations. Light density function on the illuminated plan is deduced, and the merit function for uniform illumination in certain area is defined in this paper. By using the optical design software ZEMAX EE, the search of the optimal value for the given focal length is done. The computer simulation results show that by producing spherical aberrations correctly a better uniformity illumination can be obtained on the illuminated area in certain distance successfully.
The optical system of an infrared multi-spectrum scanner used on the resource satellite is presented in this paper. The principles of spectrum-dividing and imaging, the designing of optical system, the optimization of the assemblage and the adjusting of relay optical system are discussed. According to the general principles of infrared systems, R-C system is used in designing of the primary optical system. There are two methods to design the relay optical system, one of which consists of a complex prism and the other uses a binary optical element. The results and imaging quality of the two methods generated by ZEMAX are given. In the system using complex prism, each wavelength band consists of an R-C system. The diffractive system uses diffractive-refractive hybrid systems to divide spectrum, image and achromatize. The results show that the image quality of the designed system is good enough to meet the practical requirements.
As a new research field, biochip has enjoyed its rapid development in the past 10 years. Today, most of the biochip scanning systems are fluorescent confocal scanning systems. The conventional fluorescent confocal scanning system has few limits in some kind of biochips, such as cell-chip, tissue-chip and so on, because these biochips need a long working distance to add medicament or reagent in it real-time. The longer the working distance is, the more convenient to add the medicament or reagent. However, the conventional fluorescent confocal scanning system can’t have long working distance, especially when the system has high resolution and large aperture. In this paper, a dual-axis fluorescent confocal scanning system with a long working distance and high resolution has been presented. In the dual-axis fluorescent confocal scanning system, the incident light is tilt to the axis, which can decrease the bleaching of fluorescent induced by the laser. The working distance of the system is 15 mm and the numerical aperture is 0.35. The phase aberrations of objective lens, including the spherical aberrations and the chromatic aberrations corresponding to wavelength 532 nm, 570 nm, 635 nm, 670 nm, are corrected very well. The encircled energy diagram of the lens is good to the diffraction limit. The image spot diagram, the ray aberration fan diagram, the transverse ray fan plot and the modulation transfer function, are studied also. The image quality of the system designed in this paper is good enough to meet the practical requirements.
Polarization aberration is one of the most important factors affecting the performance of optical systems, especially in systems which have many reflectors. The polarization response characters of the reflectors will change the polarization state of the incident light and the polarization aberration will affect the imaging quality of the system. In many resource satellites R-C reflective systems are often used in primary optical systems. The main elements of the R-C reflective systems are reflectors coated with thin films, so polarization aberration must be controlled to improve the imaging quality of the systems. In this paper ZEMAX software is used to realize the simulation of the optical system of a resource satellite and polarization analysis of the system is presented. According to the results of the polarization analysis, the whole optical system is optimized and the ways to control the polarization aberration are summarized. As a result of the study, a conclusion can be drawn that polarization is an important aspect in optical design. To achieve good imaging quality, polarization aberration must be controlled very well, moreover, optical thin film design should be considered while designing optical systems.
In order to measure the vibrant track of a cable crossing a river, a complex optical system is introduced to realize the image of a rectangle on a CCD image surface. The quantitative diagnosis of the system's aberrations reveals that the distortion is beyond the tolerance. A new and accurate method of digital correcting the distortion with asymmetrical distribution is proposed.
A new method of CCD intersection measurement in detecting multiple targets is discussed, and the math-model for the coordinate measurement of CCD is set up. This method is different from conventional measurement method in that it is able to detect many targets at the same time according to diverse gray level. And this model can improve the measurement accuracy and increase computing speed.
Methods of getting uniform illumination are introduced in this paper. Studies on a new optical components -- Rod lens are carried out and rules of its uniformity changing with respect to its size are deduced.