共查询到20条相似文献,搜索用时 62 毫秒
1.
A grating surface can drive the liquid crystal molecules to orientate
along the direction parallel or vertical to the projected plane of
the grating surface. The nematic liquid crystal (NLC) cell
manufactured with two pre-treated grating surface substrates may
realize the vertical display, parallel display and twist display. In
this paper, the threshold property of this NLC cell is investigated
systematically. With the Frank elastic theory and the equivalent
anchoring energy formula of grating surface substrate, the analytic
expressions of the threshold voltage related to three displays are
obtained, which are dependent on their geometrical parameters such
as amplitude δ and pitch λ of the grating surface
substrate. For a certain anchoring strength, the threshold voltage
increases or decreases with the increase of the value
δ/λ of the different displays. 相似文献
2.
3.
提出一种位相调制的实时联合变换相关器。它采用液晶显示屏作为输入器件,用液晶光阀记录和显示联合功率谱。利用液晶显示屏上的光栅状结构的衍射级,提高光能的利用率,并充分利用液晶光阀的有效使用面积。采用成像透镜放大各衍射级的联合频谱,适应液晶光阀较低的分辨率要求。在相关器的光路中插入两块倾斜的平行平面玻璃板,以改变各衍射级的参考图像和目标图像之间的位相差。这种方法可产生比传统的实时联合变换相关器更好的输出相关性能。实验结果证实了该系统设计及性能分析的正确性 相似文献
4.
Shigeto Omori 《Optical Review》2001,8(4):254-259
A data projector using three liquid crystal display panels has a complex optical system. The illuminating optics separate the beam from a light source into three primary colors and separate those into opposite polarizations using multi-layer films and prisms. A reflection grating with the period of subwavelength has high diffraction efficiency for p polarized light and high regularly reflectance for s polarized light. The diffraction angle of a grating largely depends on the wavelength, because a diffractive optical element (DOE) has large chromatic dispersion. The grating with the period of subwavelength can separate the unpolarized light into polarization components effectively using its polarization dependency and can separate white light into color components using its chromatic dispersion simultaneously. The grating makes the optical system simpler and smaller than those with conventional devices. In this paper the efficiency of polarization separation for the grating is calculated by a rigorous analytical method. Next, the condition for color separation is calculated by Snell#x0027;s law, and an optical system using a grating that performs polarization and color separation is proposed. Experimental results of the DOE fabricated are well matched with those of this simulation. 相似文献
5.
In this paper, we present an approach based on Mueller polarimetry for dimensional characterization of periodic structures with sample sizes smaller than the illuminating beam spot. The relevant theoretical background based on Mueller matrix formalism is presented. The sample, a photoresist grating box surrounded by silicon substrate, was measured in conical configuration by means of a spectroscopic Mueller polarimeter whose beam was illuminating both the grating and the substrate. By translating the boundary between these two regions through the beam we could follow the depolarization effect related to the incoherent superposition of the light reflected by the grating and the substrate. The grating’s optical response was modeled by rigorous coupled-wave analysis. The optimized geometrical parameters of the grating (the line width, the grating depth, and the side-wall angle) show very good consistency for all sample positions with 15% or more of the spot area covered by the grating. Another source of depolarization, the finite spectral resolution of the polarimeter was also taken into account in the analysis, leading to a good quantitative agreement with the sharp “depolarization lines” observed in the measured Mueller spectra. 相似文献
6.
Curved Ferroelectric Liquid Crystal Matrix Displays Driven by Field-Sequential-Color and Active-Matrix Techniques 总被引:1,自引:0,他引:1
Hideo Fujikake Hiroto Sato Takeshi Murashige Yoshihide Fujisaki Taiichiro Kurita Tadahiro Furukawa Fumio Sato 《Optical Review》2006,13(1):14-19
This paper describes a curved field-sequential-color matrix display using fast-response ferroelectric liquid crystal. Black
matrix and transparent electrode patterns were formed on a thin plastic substrate by a transfer method from a glass substrate.
While a composite film of liquid crystal and micro-polymers of walls and fibers was formed between the flexible substrates
by printing, laminating and curing processes of a solution of monomers and liquid crystal, the mechanical stability was enhanced
by use of multi-functional monomers to form large display panels. The image pixels of the matrix panel were driven by an active
matrix scheme using an external switch transistor array at a frequency of 180 Hz for intermittent three-primary-color backlight
illumination. The flexible A4-paper-sized color display with 24 × 16 pixels and 60 Hz field frequency was demonstrated by
illuminating it with sequential three-primary-color lights from light-emitting diodes of the backlight. Our display system
is useful in various information displays because of its freedom of setting and location. 相似文献
7.
Kwang-Ryul Kim Sung-Hak Cho Myung-Woo Cho Byoungdeog Choi 《Applied Surface Science》2009,255(18):7835-7840
Maskless photolithographic methods have been developed using digital micromirror devices (DMDs) and grating light valves (GLVs), which are spatial light modulators (SLMs), because liquid crystal display (LCD) panel industries spend huge amounts of money for the cost of TFT (thin film resist)-LCD photomasks. The technology has been developed for implementing 2 μm bitmap resolutions, which is a requirement for the lithographic process, though the process time is still slow for mass-production system. A DMD-based maskless exposure uses 405 nm-wavelength semiconductor lasers as an illumination source and optical engines that contain DMDs, micro lens arrays (MLAs), and projection lenses. A GLV-based system consists of UV lasers and optical write engines, which are constructed with the GLV, grating optics, and imaging lenses. Since many companies have been trying to overcome the time limitations, the maskless technology will be realized in the LCD industry in near future. 相似文献
8.
We demonstrate a tunable phase grating using a polymer-stabilized blue phase liquid crystal. Because of the electric-field-induced rectangularlike phase profile, a high diffraction efficiency of 40% is achieved. Moreover, this device shows submillisecond response time. The proposed tunable phase grating holds great potential for photonics and display applications. 相似文献
9.
《中国物理 B》2015,(6)
In this paper,we demonstrate an alternative approach to fabricating an electrically tunable holographic polymer templated blue phase liquid crystal grating.This grating is obtained by preforming a polymer template comprised of periodic fringes,and then refilling it with a blue phase liquid crystal.Compared with conventional holographic polymer dispersed liquid crystal gratings,our grating can remarkably reduce its switching voltage from 200 V to 43 V while maintaining a sub-millisecond response time.The holographic polymer templated blue phase liquid crystal(HPTBPLC) grating is free from electrode patterning,thus leading to a lower cost and more flexible applications. 相似文献
10.
11.
Fally M Drevensek-Olenik I Ellabban MA Pranzas KP Vollbrandt J 《Physical review letters》2006,97(16):167803
We report strong diffraction of cold neutrons from an only 30 micro m thick holographic polymer-dispersed liquid crystal (H-PDLC) transmission grating. The light-induced refractive-index modulation for neutrons is about 10(-6), i.e., nearly 2 orders of magnitude larger than in the best photo-neutron-refractive materials probed up to now. This makes H-PDLCs a promising candidate for fabricating neutron-optical devices. 相似文献
12.
复眼透镜提高液晶投影照明系统的能量利用率 总被引:10,自引:6,他引:4
照明系统是液晶投影仪的重要组成部分.它将直接影响到投影仪的光能利用率以及色彩等系统性能。对于复眼照明系统,复眼透镜的良好设计可以大人提高系统的能量利用率。在对液晶投影照明系统的原理进行分析的基础上,提出了两种复眼透镜的设计方案。两种方案均采用矩形子复眼,便于设计和加工。通过对复眼透镜中每个子复眼进行偏心以及改变其形状大小来提高系统能量利用率。计算机模拟结果表明,两种设计方案与传统设汁相比,在光能利用率上分别提高了16.5%和26.3%,并且具有较高的均匀性。最后,还对两种复眼透镜的设计方案进行了分析和比较。 相似文献
13.
Kota Chaen 《Optics Communications》2007,280(1):165-172
Liquid crystal spatial light modulators, which are widely used as display devices for computer-generated holograms, have modulation characteristics that depend on spatial frequency. We describe a method for displaying a computer-generated hologram on a liquid crystal spatial light modulator with compensation of its spatial frequency response. Using this method, we demonstrate a binary phase grating with smaller dependence on the spatial frequency. We also demonstrate application of the display method to holographic femtosecond laser processing. 相似文献
14.
根据液晶分子扭转排列特性,指出了光在液晶中的偏振方向扭转的角度与光在液晶中的传播距离有关,较好地解释了旋转手机液晶显示器的黑白图案反转现象. 相似文献
15.
本文从编码栅对光源、物函数、谱函数的调制原理出发,从三个方面分析了编码栅在光信息处理中的作用及应用实例。 相似文献
16.
The anchoring properties of substrate with a grating surface are
investigated analytically. The alignment of nematic liquid
crystal (NLC) in a grating surface originates from two
mechanisms, thus the anchoring energy consists of two parts. One
originates from the interaction potential between NLC molecules
and the molecules on the substrate surface, and the other stems
from the increased elastic strain energy. Based on the two
mechanisms, the expression of anchoring energy per unit area of
a projected plane of this grating surface is deduced and called
the equivalent anchoring energy formula. Both the strength and
the easy direction of equivalent anchoring energy are a function
of the geometrical parameters (amplitude and pitch) of a grating
surface. By using this formula, the grating surface can be
replaced by its projected plane and its anchoring properties can
be described by the equivalent anchoring energy formula. 相似文献
17.
The modulus of optical spatial coherence established by an incoherent light source was measured with a revised experimental setup of the Thompson and Wolf experiment. We used a liquid crystal display as a programmable aperture, which replaced the mechanical aperture controls used previously and provided a robust way to address the position-dependent spatial coherence. As a demonstration, the angular diameter, 0.982′, of an extended light source was estimated from a visibility analysis of the diffraction fringes.
相似文献18.
《中国物理 B》2019,(7)
A new optical system for an augmented reality(AR) display is proposed in this paper.The optical system mainly includes a ray deflector, coupling input grating, optical waveguide, and coupling output grating.Both the ray deflector and the coupling input grating are designed based on the diffraction characteristics of the polarization grating, and the coupling output grating is the Bragg reflection grating.Compared with other AR schemes, this AR optical system not only reduces the number of projections from two to one, but also improves the efficiency of light coupling into the optical waveguides.The energy loss is reduced by utilizing the single-order diffraction characteristics of the polarization grating in its coupling input structure.The light deflector uses the polarization selectivity of the polarization grating and the characteristics of the rotating light of the twisted nematic liquid crystal layer to realize beam deflection.The working principle of the optical system is experimentally and theoretically demonstrated. 相似文献
19.