共查询到19条相似文献,搜索用时 171 毫秒
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在前人的单圆孔电极液晶透镜的基础上进行了改进,使用聚酰亚胺取代玻璃作为绝缘层,得到了通光孔径为2mm、工作电压最低为1.1V_(rms)的新型液晶透镜.结合几何光学和液晶理论提出了不同于前人解释液晶透镜原理的模型,推导出该液晶透镜的焦距公式以及相位延迟公式.在1.1~20V_(rms)电压范围下测试,得到与公式计算值基本一致的该液晶透镜的焦距范围20~480mm.重点研究了该液晶透镜的调制传递函数(MTF),发现该液晶透镜的光学成像能力与控制电压成正比关系,随着电压的增大该液晶透镜的成像性能逐渐增强. 相似文献
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液晶变焦透镜由于其结构紧凑,低功耗,性能稳定,易于制备等特点,在图像处理,光通信,机器视觉,可切换2D/3D显示等方面应用广泛,但是工作电压高阻碍了其实际应用和商业化。本文提出了一种梯形凸起电极结构的液晶变焦透镜,用TechWiz LCD 3D软件模拟了此种结构的电场和液晶分子分布,对比分析了液晶盒厚、电极高度、电极梯角和电极宽度与间隔比对液晶透镜工作电压的影响。模拟结果显示,当液晶盒厚为10μm时,液晶透镜的驱动电压可以降低到10V以内;在焦距变化范围相同的情况下,梯形凸起电极液晶透镜比传统的平面电极液晶透镜的工作电压降低了35.8%。对于梯形凸起电极结构的液晶变焦透镜,当电极高度占液晶盒厚40%,电极梯角选为60°,电极宽度与间隔比为100∶50时,其工作电压最低。 相似文献
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光场成像可以获取场景的三维信息。通过在主透镜和图像传感器之间插入一个微透镜阵列,不仅可以记录光线的辐射度,还记录了光线入射的方向。提出了使用梯度折射率液晶微透镜阵列进行光场成像的方法。该阵列基于向列相液晶材料,利用其各向异性和双折射的特点,通过紫外光刻技术和湿法刻蚀技术制作,具有圆孔阵列图案。在该阵列的上下电极之间加载一个交流电压信号后,每个微透镜可以有效会聚入射光,搭建了测试系统来测试该阵列的聚焦特性和焦距。将该阵列与一个主透镜和一片图像传感器耦合得到一个光场成像相机,并使用该相机采集了图像。 相似文献
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提出了一种基于聚合物突起液晶透镜阵列。该液晶透镜阵列的周期性聚合物突起上镀有氧化铟锡透明电极,利用介电层抹平相剖面,通电状态下在液晶层内部产生沿透镜孔径呈线性变化的垂直电场,在液晶层内形成了呈中心对称的梯度折射率分布,从而使液晶层对入射光线有聚焦作用。优化后的液晶透镜阵列采用较薄的液晶层,大幅缩短了液晶透镜阵列的响应时间。所提液晶透镜阵列具有工作电压较低、电极简单、基板内部侧平面化和液晶层厚度均匀等优点。仿真结果表明,通过改变驱动电压,该液晶透镜阵列的焦距可以从无穷大连续调节到1.28 mm。 相似文献
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《液晶与显示》2021,(4)
为了在不改变液晶透镜孔径的基础上减小其焦距,本文提出了一种基于大Δn液晶材料的短焦距透镜阵列。该透镜阵列采用大Δn液晶材料,使其在低驱动电压下便可以积累较大的光程差。下基板采用ITO驱动电极与ITO接地电极交替排列的结构,且ITO驱动电极位于介电层上方。ITO接地电极使其边缘区域内存在弱电场,介电层平滑了液晶层内的电场。该设计不仅在大孔径范围内实现抛物线形的相位分布,且减小了驱动电压。仿真结果表明,当驱动电压为6V时,该液晶透镜阵列的相位分布曲线与理想抛物线匹配较好。单个液晶透镜中心与边缘的相位差为42.17π左右,使其达到最小焦距约1.72mm。当驱动电压从0V增加到6V时,液晶透镜阵列的焦距从∞减小到1.72mm左右。因此,该液晶透镜阵列可以应用于2D/3D可切换显示、AR显示等领域。 相似文献
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针对传统显微镜结构复杂且视场角小等问题,提出一种两路低电压驱动的液晶微透镜阵列结构,透镜的焦距由3个电极控制,中间电极为圆孔阵列图案电极,作为孔径光阑以阻止微透镜外的杂散光。对该阵列的波前和光焦度进行了测试,搭建了一套简易液晶微透镜阵列直接成像系统,每个微透镜都对待观察物体的不同区域成像,通过近平行光照明减小相邻微透镜间的串扰,拼接所有单元图像得到完整图像。该系统无需额外的光学器件,结构简单紧凑。液晶微透镜阵列具有大视场,成像区域具备可扩展性,为实现大视场下的简易显微成像提供了新思路。 相似文献
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微小光学与异形孔径微透镜阵列研究 总被引:1,自引:1,他引:0
讨论了微小光学的发展和异形孔径(正方形和六角形)微透镜阵列的制作。自聚焦透镜的制作加速了微小光学的产生,微透镜阵列器件的应用,促使微小光学迅猛发展,异形孔径微透镜阵列的研制,开创了微小光学新的研究领域。重点对异形自聚焦透镜和异形孔径微透镜阵列的理论和实验研究工作进行讨论,给出了有益的结果。 相似文献
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随着红外技术的不断发展,空间大口径红外光学元件的需求日益增长,其各项制造指标也逐渐接近可见光级光学元件的制造要求,由此对新型空间红外光学元件的加工和检测技术均提出了更高的挑战。针对大口径 的高陡度超薄硅基红外透镜,提出了以超声铣磨-机器人研抛-离子束精抛为工艺链路的加工方案,改善了传统红外工艺路线存在的低效率、表面高频误差等问题。针对凸非球面轮廓检测中支撑引起的测试误差,在粗抛和精抛阶段分别采用了柔性缓冲支撑与三点强迫位移支撑方法,有效解决了大口径高陡度超薄透镜测试中的支撑变形问题。经过理论仿真与实验验证,证明该测试方法具有较好的一致性。通过改进的轮廓检测方法,实现了轮廓测试中支撑误差的准确分离,有效提升了加工的极限精度。最终大口径红外透镜凸非球面加工精度达RMS λ/50 (λ=632.8 nm),满足设计指标要求。 相似文献
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A comparison among 1-, 3-, and 7-horn feeds for a 37-beam MBA 总被引:2,自引:0,他引:2
A very common multiple beam antenna (MBA) configuration consists of a collimating device illuminated by an array of feeds. The collimating device is usually a reflector or a lens. The feeds are usually horn antennas with a circular aperture. The reflector is usually offset-fed to eliminate aperture blockage; the lens is center fed. The antenna's feeds are excited to produce a finite number of beams, so as to provide contiguous coverage of the field of view. The designer is forced to minimize the angular spacing between adjacent beams in order to maximize the minimum gain over the antenna's field of view. On the other hand, the feed horn's aperture gain is maximized when the feed horn spacing and its aperture diameter are equal. This results in antenna efficiency of the order of 30% when a single feed horn is excited to produce a beam. When a cluster of 3 or 7 adjacent feed horns are excited to produce a single beam, antenna efficiency can be increased to 50%. When it is tolerable, several identical antenna apertures can be used to replace a single aperture configuration. In this case, each of M apertures produces approximately N/M beams of an MBA that produces N beams. Horns producing adjacent beams do not illuminate the same aperture. This permits the use of a much larger horn aperture for a given beam spacing. This results in reduced spillover, higher gain of each beam, and increased antenna efficiency of each aperture. This paper investigates the maximization of gain for several lens antennas. It shows that antenna gain is increased as its focal length is decreased. That is, a focal length-to-diameter ratio (F/D) less than 1 is preferred 相似文献
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Fabrication of Copper Window Electrodes with ≈108 Apertures cm−2 for Organic Photovoltaics 下载免费PDF全文
《Advanced functional materials》2018,28(36)
A powerful approach to increasing the far‐field transparency of copper film window electrodes which simultaneously reduces intraband absorption losses for wavelengths <550 nm and suppresses reflective losses for wavelengths >550 nm is reported. The approach is based on incorporation of a random array of ≈100 million circular apertures per cm2 into an optically thin copper film, with a mean aperture diameter of ≈500 nm. A method for the fabrication of these electrodes is described that exploits a binary polymer blend mask that self‐organizes at room temperature from a single solution, and so is simple to implement. Additionally all of the materials used in electrode fabrication are low cost, low toxicity, and widely available. It is shown that these nanostructured copper electrodes offer an average far‐field transparency of ≥80% and sheet resistance of ≤10 Ω sq−1 when used in conjunction with a conventional solution processed ZnO electron transport layer and their utility in inverted organic photovoltaic devices is demonstrated. 相似文献
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A dielectric lens antenna that is a special case of an extended hemispherical dielectric lens and is operated in the diffraction-limited regime is considered. The dielectric lens antenna is fed by a planar antenna that is mounted on the flat side of the dielectric lens antenna, using it as a substrate, and the combination is termed a hybrid antenna. Beam pattern and aperture efficiency measurements were made at millimeter and submillimeter wavelengths as a function of the extension of the hemispherical lens and of lens size. An optimum extension distance for which excellent beam patterns and simultaneously high aperture efficiencies can be achieved is found experimentally and numerically. At 115 GHz the aperture efficiency was measured to be (76±6)% for a diffraction-limited beam with sidelobes below -17 dB. Results for a single hybrid antenna with an integrated superconductor-insulator-superconductor (SIS) detector and a broadband matching structure at submillimeter wavelengths are presented. The hybrid antenna is space efficient in an array due to its high aperture efficiency, and is easily mass produced, thus being well suited for focal plane heterodyne receiver arrays 相似文献
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The Misell (1973) phase retrieval algorithm for microwave holography requires the capability to axially move an antenna's subreflector or feed to obtain a defocused far-field magnitude pattern. A microwave lens may be used as an alternative method of defocusing an antenna. A metal plate lens has been designed and constructed for use in phase retrieval holography at the Georgia Tech Woodbury Research Facility. Its phase variation across the aperture was chosen to have a parabolic profile in order to imitate the effect of subreflector or feed translation. A two-dimensional (2-D) finite-difference time-domain simulation has been performed to characterize the lens. Measurements, using the measured aperture phase of the lens transfer function as a phase correction term in the Misell algorithm, show the results to be comparable with that of phase coherent holography. Other types of microwave lenses such as a Fresnel zone plate, a bed of circular waveguides, and a standard dielectric lens are also being studied. 相似文献
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A simple lens concept that transforms the aperture field of a conical horn antenna driven by an azimuthally symmetric mode is presented. It is shown that with the appropriate lens geometry the radiated field of the conical horn will exhibit a boresight null (no lens), a boresight peak with linear polarisation, or a boresight peak with circular polarisation 相似文献