共查询到19条相似文献,搜索用时 31 毫秒
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非球面红外透镜模压成型时,通过提高成型阶段温度可缩短透镜压切时间,从而提高模压效率,但易在透镜表面产生雾斑,像造透镜不良。本文通过对透镜雾斑的形成机理进行分析,采用一种非接触式预热模压工艺降低透镜雾斑的形成,并在多站式模压机上进行模压实验,使用能谱仪对雾斑的元素进行检测和分析。在本次模压实验中采用非接触式预热方式,当预热间隙为1 mm时将成型温度由206℃提升至211℃,透镜表面无雾斑生成,并使压切时间缩短了21 s。实验结果表明,在多站式模压中采用非接触式预热方式,可以有效消除透镜雾斑的形成。检测结果表明,成型阶段透镜材料的挥发对雾斑的形成起主导作用。 相似文献
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非球面零件在光学仪器小型化、集成化的发展中起着非常重要的作用。用模压成形方法生产小尺寸非球面透镜是最经济、重复性最好的方法。本文主要讨论了模压玻璃非球面透镜的材料选择、模具制造等问题。 相似文献
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介绍了玻璃光学元件精密模压成形技术的原理、玻璃材料、模具制造、模具表面镀膜、结合有限元仿真的模压工艺优化和模压成形设备等核心技术的研究进展,并讨论了当前存在的问题。通过探讨玻璃模压成形技术在自由曲面、微结构、衍射结构表面和晶圆阵列等光学元件中的应用现状,对玻璃元件精密模压成形技术的发展趋势和挑战进行了展望。 相似文献
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衍射光学元件较球面、非球面光学元件在校正色差方面具备较大优势,尤其是在红外光学领域,应用衍射光学元件可进一步增加光学系统的设计自由度。随着红外光学市场的进一步增大,常规的衍射光学金刚石车削技术难以满足大规模需求,精密模压技术成为解决上述问题的关键技术。模具设计是实现精密模压的重点,为了缩减模具设计周期,该文采用有限元仿真方法对模具进行预先设计及补偿,并试加工。采用单站式精密模压机对设计的模具进行了精密模压试验。模压试验结果表明:采用合理的工艺参数,能够实现衍射光学元件面形精度PV达到0.56 μm,位置误差<0.011 mm,环带高度误差<0.12 μm,验证了仿真预先补偿在衍射光学模具设计中的有效性。 相似文献
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最近非球面光学系统的生产技术 总被引:1,自引:0,他引:1
<正> 袖珍唱盘即所谓的CD用的精密非球面透镜现月产约达100万件,这是几年前还不敢设想的技术和生产量,可以说这是日本独有的新生产业。这种技术并不只局限于CD,而且还广泛应用于记忆装置的光盘中。在塑料、无机光学玻璃的精密非球面模压成型技术方面也有不少引人注目的进展,它需要有更尖端的加工技术和检测技术。在光学系统中引入非球面后,有时会使球面组合时难以做到的:消像差变得简单易行。换言知,由球面组合的相当复杂的系统,引入 相似文献
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Dynamic fragility of bulk metallic glass (BMG) of Zr64Cu16Ni10Al10 alloy is studied by three-point beam bending methods. The fragility parameter mfor Zr64Cu16Ni10Al10 BMG is calculated to be 24.5 at high temperature, which means that the liquid is a "strong" liquid, while to be 13.4 at low temperature which means that the liquid is a "super-strong" liquid. The dynamical behavior of Zr64Cu16Ni10Al10 BMG in the supercooled region undergoes a strong to super-strong transition. To our knowledge, it is the first time that a strong-to-superstrong transition is found in the metallic glass. Using small angle x-ray scattering experiments, we find that this transition is assumed to be related to a phase separation process in supercooled liquid. 相似文献
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Jean-Pierre Eckmann 《Journal of statistical physics》2007,129(2):289-309
We propose and study a model with glassy behavior. The state space of the model is given by all triangulations of a sphere
with n nodes, half of which are red and half are blue. Red nodes want to have 5 neighbors while blue ones want 7. Energies of nodes
with other numbers of neighbors are supposed to be positive. The dynamics is that of flipping the diagonal of two adjacent
triangles, with a temperature dependent probability. We show that this system has an approach to a steady state which is exponentially
slow, and show that the stationary state is unordered. We also study the local energy landscape and show that it has the hierarchical
structure known from spin glasses. Finally, we show that the evolution can be described as that of a rarefied gas with spontaneous
generation of particles and annihilating collisions. 相似文献
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Multiferroic behavior in an isotropic Heisenberg spin glass with Gaussian random fields, incorporated by magneto-electric coupling derived from the Landau symmetry argument, are investigated. Electric dipole glass transitions at finite temperature, due to coupling, are demonstrated by Monte Carlo simulation. This electric dipole glass state is solely ascribed to the coupling term with chiral symmetry of the magnetization, while the term associated with the spatial derivative of the squared magnetization has no contribution. 相似文献
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The principle of operation of a glass-fiber image converter is outlined. Calculations are made indicating that a Perot-Fabry interferometer used with the image converter and an electro-optical amplifier gives an increased relative aperture, compared with the usual setup which consists of the interferometer with a diaphragm and a photomultiplier. Some results obtained with an experimental image-converter sample and the technique of manufacturing such converters are described.The authors express their gratitude to the laboratory assistant R.P. Rebezovaya, who helped in sorting and arranging the fibers. 相似文献
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A Modified Glass Formation Criterion for Various Glass Forming Liquids with Higher Reliability 下载免费PDF全文
X. H. Du J. C. Huang 《中国物理快报》2007,24(5):1335-1338
A modified indicator of the glass forming ability (GFA) from the previous 7 = Tx/(Tl + Tg) for various glass forming liquids is proposed based on a conceptual approach which combines more acceptable physical metallurgy views in terms of the time-temperature-transformation diagrams. It is found that the glass forming ability for glass forming liquids is closely associated mainly with two factors, i.e. (2Tx - Tg) and Tl (wherein Tx is the onset crystallization temperature, Tg the glass transition temperature, and Tl the liquidus temperature), and could be predicated by a unified parameter γm defined as (2Tx - Tg)/Tl. This approach is confirmed and validated by experimental data in various glass forming systems including oxide glasses, cryoprotectants and metallic glasses, which all shows a higher reliability when their glass forming ability is predicted by the modified parameter. 相似文献