scholarly journals Electrically Tunable-Focusing Liquid Crystal Microlens Array with Simple Electrode

Crystals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 431 ◽  
Author(s):  
Li-Lan Tian ◽  
Fan Chu ◽  
Hu Dou ◽  
Lei Li ◽  
Qiong-Hua Wang
Keyword(s):  
Liquid Crystal ◽  
Indium Tin Oxide ◽  
Focal Length ◽  
Microlens Array ◽  
Operating Voltage ◽  
Focusing Effect ◽  
Horizontal Orientation ◽  
Wide Range ◽  
Planar Electrodes ◽  
The Individual

An electrically tunable-focusing liquid crystal (LC) microlens array exhibiting a wide-range tunable focal length is proposed. The lower substrate has strip indium tin oxide (ITO) electrodes, the upper substrate has periodic ITO electrodes with a certain gap coated on the inner surface., and an LC microlens is generated between the two strip electrodes. For each LC microlens, the gap between the top planar electrodes is directly above the center of the microlens. Unlike the conventional LC lens, the individual LC microlens is not coated with ITO electrodes on the central part of its upper and lower substrates, which helps to maintain the LC’s horizontal orientation. In the voltage-off state, the focal length of the microlens array is infinity because of the homogeneous LC alignment. At a given operating voltage, an ideal gradient refractive index distribution is induced over the homogeneous LC layer, which leads to the focusing effect. The simulation result shows that the focal length of the LC microlens could be gradually drawn to 0.381 mm with a change of voltage.

scholarly journals Depth-of-Field-Extended Plenoptic Camera Based on Tunable Multi-Focus Liquid-Crystal Microlens Array

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4142 ◽  
Author(s):  
Mingce Chen ◽  
Wenda He ◽  
Dong Wei ◽  
Chai Hu ◽  
Jiashuo Shi ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Radiation Power ◽  
Focal Length ◽  
Microlens Array ◽  
Oxide Semiconductor ◽  
Depth Of Field ◽  
Digital Refocusing ◽  
Wide Range ◽  
Cmos Sensor ◽  
Plenoptic Camera

Plenoptic cameras have received a wide range of research interest because it can record the 4D plenoptic function or radiance including the radiation power and ray direction. One of its important applications is digital refocusing, which can obtain 2D images focused at different depths. To achieve digital refocusing in a wide range, a large depth of field (DOF) is needed, but there are fundamental optical limitations to this. In this paper, we proposed a plenoptic camera with an extended DOF by integrating a main lens, a tunable multi-focus liquid-crystal microlens array (TMF-LCMLA), and a complementary metal oxide semiconductor (CMOS) sensor together. The TMF-LCMLA was fabricated by traditional photolithography and standard microelectronic techniques, and its optical characteristics including interference patterns, focal lengths, and point spread functions (PSFs) were experimentally analyzed. Experiments demonstrated that the proposed plenoptic camera has a wider range of digital refocusing compared to the plenoptic camera based on a conventional liquid-crystal microlens array (LCMLA) with only one corresponding focal length at a certain voltage, which is equivalent to the extension of DOF. In addition, it also has a 2D/3D switchable function, which is not available with conventional plenoptic cameras.

scholarly journals Electrically-Tunable Blue Phase Liquid Crystal Microlens Array Based on a Photoconductive Film

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 65 ◽  
Author(s):  
Bing-Yau Huang ◽  
Shuan-Yu Huang ◽  
Chia-Hsien Chuang ◽  
Chie-Tong Kuo
Keyword(s):  
Refractive Index ◽  
Liquid Crystal ◽  
Electric Field ◽  
Uv Light ◽  
Focal Length ◽  
Incident Light ◽  
Microlens Array ◽  
Gradient Distribution ◽  
Phase Liquid ◽  
Blue Phase

This paper proposes an effective approach to fabricate a blue phase liquid crystal (BPLC) microlens array based on a photoconductive film. Owing to the characteristics of photo-induced conducting polymer polyvinylcarbazole (PVK), in which conductivity depends on the irradiation of UV light, a progressive mask resulting in the variation of conductivity is adopted to produce the gradient distribution of the electric field. The reorientations of liquid crystals according to the gradient distribution of the electric field induce the variation of the refractive index. Thus, the incident light experiences the gradient distribution of the refractive index and results in the focusing phenomenon. The study investigates the dependence of lens performance on UV exposure time, the focal length of the lens, and focusing intensities with various incident polarizations. The BPLC microlens array exhibits advantages such as electrically tunability, polarization independence, and fast response time.

Liquid-crystal lens with a focal length that is variable in a wide range

2004 ◽  
Vol 43 (35) ◽  
pp. 6407 ◽  
Author(s):  
Mao Ye ◽  
Bin Wang ◽  
Susumu Sato
Keyword(s):  
Liquid Crystal ◽  
Focal Length ◽  
Wide Range ◽  
Liquid Crystal Lens

Fabrication of a focal length variable microlens array based on a nematic liquid crystal

2003 ◽  
Vol 21 (1-3) ◽  
pp. 643-646 ◽  
Author(s):  
Yoonseuk Choi ◽  
Jae-Hong Park ◽  
Jae-Hoon Kim ◽  
Sin-Doo Lee
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Focal Length ◽  
Microlens Array ◽  
Length Variable

scholarly journals Multi-View 2D/3D Switchable Display with Cylindrical Liquid Crystal Lens Array

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 715
Author(s):  
Fan Chu ◽  
Di Wang ◽  
Chao Liu ◽  
Lei Li ◽  
Qiong-Hua Wang
Keyword(s):  
Liquid Crystal ◽  
Indium Tin Oxide ◽  
Fast Response ◽  
Experimental Result ◽  
Operating Voltage ◽  
Lens Array ◽  
Display Devices ◽  
Periodic Strip ◽  
2D And 3D ◽  
Liquid Crystal Lens

We propose a multi-view 2D/3D switchable display by using cylindrical liquid crystal (LC) lens array with a low operating voltage and fast response time. The cylindrical LC lens array is composed of three parts: the LC layer, a top-plane indium tin oxide (ITO) electrode, and bottom periodic strip ITO electrodes. In the voltage-off state, the cylindrical LC lens array is equivalent to a transparent glass substrate and the viewers can see a clear 2D image. In the 3D mode, the cylindrical LC lens array can be used as a cylindrical lens array under a suitable operating voltage. As a result, the 2D and 3D images can be switched according to the state of the cylindrical LC lens array. The experimental result shows that the 2D/3D switchable display with the cylindrical LC lens array has a wider viewing angle, has no moiré pattern, and is much thinner compared to the other 2D/3D switchable display devices.

scholarly journals Liquid crystal lens with large focal length tunability and low operating voltage

2007 ◽  
Vol 15 (18) ◽  
pp. 11328 ◽  
Author(s):  
Hongwen Ren ◽  
David W. Fox ◽  
Benjamin Wu ◽  
Shin-Tson Wu
Keyword(s):  
Liquid Crystal ◽  
Focal Length ◽  
Operating Voltage ◽  
Liquid Crystal Lens

scholarly journals Evaporative deposition of SiO2 nanoparticles multilayer on ITO substrates and application for vertical alignment of liquid crystals - Effect of dichroic dye

2021 ◽  
Vol 2070 (1) ◽  
pp. 012071
Author(s):  
Ankit Rai Dogra ◽  
Vandna Sharma ◽  
Partha Khanra ◽  
Pankaj Kumar
Keyword(s):  
Liquid Crystal ◽  
Indium Tin Oxide ◽  
Contrast Ratio ◽  
Sio2 Nanoparticles ◽  
Operating Voltage ◽  
Vertical Alignment ◽  
Dichroic Dye ◽  
Electro Optic ◽  
Coated Cell ◽  
Vertically Aligned

Abstract In this work the SiO2 nanoparticles layer was deposited by solvent evaporation on ITO substrates and used for vertical alignment of pure and dye doped liquid crystal (LC) in confined cells. The pure nematic liquid crystal (NLC) material was filled into SiO2 layer coated cell by the capillary injection method. The 0.5 wt.% of dichroic dye added into the LC mixture and studied its effect on electro-optic behaviour of display cell. The FESEM study reveals the multilayered deposition of the SiO2 on Indium tin oxide (ITO) substrates. Conoscopic and polarised optical microscopy (POM) study show good dark black and bright textures at OFF and ON state under the cross polarizers and confirm vertical alignment (VA) of LC molecules. The electro-optical (E-O) study shows the lower threshold and operating voltage with higher contrast ratio in dye doped vertically aligned LC (VALC) cell as compare to the pure SiO2 coated VALC cell.

Cylindrical Liquid Crystal Microlens Array With Rotary Optical Power and Tunable Focal Length

2015 ◽  
Vol 36 (6) ◽  
pp. 582-584 ◽  
Author(s):  
Jose Francisco Algorri ◽  
Virginia Urruchi ◽  
Noureddine Bennis ◽  
Jose Manuel Sanchez-Pena ◽  
Jose Manuel Oton
Keyword(s):  
Liquid Crystal ◽  
Focal Length ◽  
Optical Power ◽  
Microlens Array

Comparison of Deterministic and Linear Cosine Spatial Filtering of Transmission Electron Micrographs

1972 ◽  
Vol 30 ◽  
pp. 596-597
Author(s):  
David A. Ansley
Keyword(s):  
Spherical Aberration ◽  
Focal Length ◽  
Chromatic Aberration ◽  
Spatial Filter ◽  
Operating Conditions ◽  
Objective Lens ◽  
List Type ◽  
Spatial Filters ◽  
Transmission Electron ◽  
Wide Range

The coherence of the electron flux of a transmission electron microscope (TEM) limits the direct application of deconvolution techniques which have been used successfully on unmanned spacecraft programs. The theory assumes noncoherent illumination. Deconvolution of a TEM micrograph will, therefore, in general produce spurious detail rather than improved resolution.A primary goal of our research is to study the performance of several types of linear spatial filters as a function of specimen contrast, phase, and coherence. We have, therefore, developed a one-dimensional analysis and plotting program to simulate a wide 'range of operating conditions of the TEM, including adjustment of the:(1) Specimen amplitude, phase, and separation(2) Illumination wavelength, half-angle, and tilt(3) Objective lens focal length and aperture width(4) Spherical aberration, defocus, and chromatic aberration focus shift(5) Detector gamma, additive, and multiplicative noise constants(6) Type of spatial filter: linear cosine, linear sine, or deterministic

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