Key Engineering Materials Vol. 552

Abstract: On the basis of optical correlation detection, joint transform correlator(JTC) is widely used in military, aviation and intelligentization and so on. It has the advantages of great flexibility and high precision of recognition. The optical system is applied to receive the infrared radiation of the target. Athermalization is the key to stabilizing the optical performance with respect to off-design temperature. Therefore, the image quality of optical system in different temperatures plays an important role in JTC. In order to improve the environmental adaptability of JTC, the infrared telephoto system with high image quality and high performance-price ratio is designed for wavelength 8μm～12μm to detect target in a large range of temperature. This telephoto lens is composed of four refractive lenses. Three materials, zinc selenide, germanium and zinc sulfide are used to compensate for the temperature. The focal length is 200 mm, the relative aperture is 1:3, and the field of view is 6.4°. This system has the characteristics of small volume and compact structure. The optical system image quality is evaluated with ZEMAX optical design software. The results have shown that MTFs in the range of -40°C to +60°C are all closed to the diffraction limited curve. The spot diagram RMS radius of each field is closed to the Airy disk radius. The system meets the requirements of technical specification and improves the ability of JTC in target tracking and recognition.

Abstract: The U.S.A has launched the Mars Orbiter. It brought a high resolution imaging science equipment, and that is the High Resolution Imaging Science Experiment camera(HIRISE). HIRISE is 0.5 m reflecting telescope, which is the highest one ever carried on a deep space mission, and it has a resolution of 1 microradian (μrad), or 0.3 m from an altitude of 300 km. HIRISE can investigate deposits and landforms resulting from geologic and climatic processes and assist in the evaluation of candidate. As a high degree of lightweight ultra-high resolution camera, the design of its FPA is unparalleled .Therefore we should study and learn it carefully. In this article, first of all we discuss and analyze the characters of the HIRISE FPA in terms of the structural layout, material selection, splicing of the CCD, the CCD package, electronics, processing and transmission, and thermal control measures implementation. Next we put forward the design method of highly lightweight space optical remote sensor FPA combined with the characters of the HIRISE FPA, which can provide a reference to the design of the FPA for some space remote sensings.

Abstract: Infrared dynamic target simulator can simulate infrared scene practicality in the laboratory, and reduce the research cost of the optical electrical system and offer recycle experiment environments， which are used to evaluate and test the infrared imaging system performance. Infrared scene projection technology based on the digital micro-mirror device (DMD) has been developed and applied to infrared target simulator, whose infrared images were obtained by modulating the launch of infrared radiation. Compared with the traditional simulator, the infrared scene simulator based on digital micro-mirror device (DMD) has a high spatial resolution and high frame rate, no dead pixels and good uniformity of characteristics. Firstly, the basic structure and the principle of the digital-mirror device are briefly introduced, and the kind and the advantage of the DLP(Digital Light Procession) system based on digital micro-mirror device (DMD) are analyzed. The key technology of the DLP(Digital Light Procession) projection system when it used in infrared wave band is analyzed. Secondly, the design process of the projection system is detailed. According to the design index required and the size of the digital micro-mirror device (DMD), a projection system consisting of three lenses and the transmissive type and aspheric technology was designed by ZEMAX optical-design software. The work wave-band is 8～12μm.The MTF curve is close to the diffraction limited curve and the size of the spot diagram is smaller than the airy disk. The result indicates that the system satisfies the design requirement and the structure of system is good.

Abstract: As an ultra-short electromagnetic waves, X-ray has a strong ability to penetrate with high-energy. The method for focusing visible spectral bands is not suitable for X-ray spectrum. At present, in X-ray astronomy, the X-ray focus mode which uses grazing incidence less than critical angle has been widely used. However, the small critical angle limits its effective aperture of the X-ray collection. This paper presents a multi-layer reflective structure working with grazing incidence and the surfaces coated multilayer high reflective for X-ray. It can guarantee the large effective entrance pupil and high energy collection. The 200mm diameter X-ray focusing device is designed as an example. It is found from simulation that a good focusing result is acquired.

Abstract: The collimator has an extensive application as an experiment equipment that can provide an infinity goal in the instrument alignment and testing.This paper provides a new type of collimator with image stabilization function in consideration of human disturbance factors, including environment micro-vibration and so on. Liquid surface which appears natural level under gravity imaging optical path of collimator can emerge through liquid refraction and reflex later. And we should make use of this phenomenon. Mathematical modeling and analysis on the principle of dynamic imaging of the liquid wedge have been made to design several optical principle charts of the collimator with image stabilization function.One of the image stabilization optical principle structure styles has been designed based on its mechanical structure.An experiment prototype is produced and is made more practical.

Abstract: Digital binoculars is the combination of digital cameras and telescopes, it not only can observe the details of the long distance target but also can record it. The field of view between photographic field lens and telescope system is the same. This paper designs the telescope system on basis of the theory of dynamic optics. The system works in visual light waveband. The field of view is , the magnification is eight and the entrance pupil diameter is 32mm. prism is selected as the image rotation prism and image stabilization prism. In order to obtain clear images in a dynamic circumstance, we utilize the rotation theorem of prism to analyze the relation between jitter compensated lens and luminous beam angle. We can calculate the position of compensated lens. So it can achieve the jitter compensation. Finally, this paper takes an application as an example. If the jittered angle is , the displacement of pixel is calculated to 1.061mm. The displacement of the compensated lens is 2.84mm. At the same time, the light still arrives to the eyepiece by the original track. So image stabilization is relative to the reference coordinate, as a result we can get the stable image.

Abstract: Optical equipments especially those for aerospace application are expected to work over a wide temperature range. The change of temperature could cause the refractive index change of infrared glass elements. Furthermore, it would lead to the defocus of the image surface and the performance degradation, so the method of temperature compensation must be adopted, which could make sure that optical system would adapt to the change of ambient temperature. A method of temperature compensation with mechanical passive compensation is briefly described, and an example is also given. The quality of image could be optimized through mechanical passive compensation,depending on the differences of metal and non-metallic thermal expansion coefficient. The results show that the optical system works stablely in the designed temperature range. It is of great importance to the athermalisation design of infrared optical system.

Abstract: Hyper spectral imaging technology is widely applied in military scout and target recognition with imaging and spectral integration. To acquire different size image and field of view, a kind of zoom hyper spectral optical system is designed in this paper. The working spectrum is from 400nm to 1000nm. The detector size is 6.4mm×4.8mm. F# is from 3.5 to 5.6, and the focal length is from 28mm to 80mm. With consideration of the reasonable MTF requirement of back relay system and the visibility threshold of human eyes, which is the final receiver, the design requirements are analyzed. The initial structure is acquired by zoom method. After optimization, the image quality of every focal length and every spectrum meets the analyzed requirements. At last, to ensure the stable image during zoom process, the cam curve is calculated with image stable theory of dynamic optics.

Abstract: A workflow of LED lighting design will be discussed in the paper. And it will analyze the influence of different LED die size distribution. It will present the design method how to design from spot source to line source and then to extended source in the mathematic theory. It means to research from 2D to 3D design about LED light source.

Abstract: Raman spectrum is a kind of characteristic spectrum. The information of molecular vibration and rotation can be obtained by studying Raman spectrum. Raman spectrum will be changed because of molecular interaction under effect of different solvent. We selected zinc gluconate as the object of research. Zinc gluconate is dissolved respectively in ethyl chloride, benzene, ring of ethane，chloroform, acetic acid, ethylene oxide, n-propanol, n-butanol solution, and Raman spectra were tested. The change of molecular internal structure and the interaction of molecular functional groups are studied by means of measuring Raman frequency shift, bandwidth, and light intensity. Thus, the information of solute structure change can be obtained. Experiments show that when zinc gluconate dissolved in the organic solvent, molecular gap became larger, its velocity increased, and stretching vibration of associating OH key group became strong. Methylenes in polar and non-polar molecule interact, and the polarization changed. In different polar solvents, Raman spectra had different changes. When the bond length increases，the stretching vibration frequency of molecules moves to the direction of low frequency. It produces red shift instead of blue shift. The results of this paper provide a basis to study molecular interactions further.