Дисертації з теми "Liquid crystal cell"
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1
Liu, Zhijian. "Photo-aligned LC cell with weak anchoring energy and specific profiles : physics & applications /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?ECED%202006%20LIU.
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2
Du, Tao. "Single cell gap transflective liquid crystal displays and the use of photoalignment technology /." View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?ECED%202009%20DU.
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3
Noda, Yohei. "EPR studies on molecular orientation of all-organic paramagnetic liquid crystals in a surface-stabilized liquid crystal cell." 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/136793.
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4
Angelo, Joseph S. Angelo. "Direct Mechanical Observation of Surface Anchoring and Disclinations Using Dynamically Reconfigurable Liquid Crystal Cell." Kent State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=kent1532646624675951.
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5
Soon, Chin Fhong. "Development of a novel cell traction force transducer based on cholesteryl ester liquid crystals : characterisation, quantification and evaluation of a cholesteryl ester liquid crystal based single cell force transducer system." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5379.
Повний текст джерелаАнотація:
In biomechano-transducing, cellular generated tension can be measured by soft substrates based on polymers but these techniques are limited either by spatial resolution or ability to detect localised cell traction forces (CTF) due to their non-linear viscous behaviour under shear rates. A newly developed cell traction force transducer system based on cholesteryl ester lyotropic liquid crystals (LCTFT) was developed to sense localised traction forces of human keratinocyte cell lines (HaCaTs), in which the length of the deformation line induced represents the intensity of the CTF exerted. The physical properties of the cholesteryl ester based lyotropic liquid crystals (LLC) were characterised by using polarising microscopy, rheology, atomic force microscopy (AFM) based nano-indentation, spherical indentation, and micro-tensile tests. The interactions of LLC with cells were studied by using cell viability studies, cytochemical treatments, widefield surface plasmon resonance (WSPR) microscopy and various immuno-staining techniques. The results show that LLC is thermally stable (0-50 °C) and linearly viscoelastic below 10% shear strain at shear rates of < 1 s⁻¹. AFM nano and spherical indentations show a good agreement on the Young's modulus of both determined at ~110 kPa which is close to the elastic modulus of the epidermis. The Poisson's ratio of LLC was determined at ~0.58 by using micro tensile tests. The biophysical interaction studies indicated that LLC is biocompatible and allowed cell attachment. Cell relaxation technique by cytochalasin-B treatment suggested that the attachment and contraction of cells on LLC was due to the contractile activity of actin cytoskeletons that are mediated by focal adhesions. The staining experiments showed that cells consistently expressed the same suites of integrins (α2, α3, α5 and β1) and ECM proteins (collagen type IV, laminin and fibronectin) on both glass and LLC coated substrates. Interfacial interaction of cells with LLC observed via the staining of actin and vinculin, and WSPR imaging suggest the association of marginal actin filaments and focal adhesions in attaching HaCaT cells to the LLC. Linear static analysis applied in the Finite Element model of focal adhesion-LC confirmed the compressive force patterns induced by cells. By applying cell relaxation techniques and Hooke's theorem, the force-deformation relationships of the LLC were derived and used for direct quantification of CTF in culture. The sensitivity of the LCTFT was implied by a wide range of CTF (10 - 140 nN) measured at high resolutions (~2 μm). Nonetheless, a custom-built cell traction force measurement and mapping software (CTFM) was developed to map CTF of single cells. Reliability of the LCTFT was evaluated by using a known pharmacological active cytokine, TGF-β1, in inducing contraction of human keratinocytes. This study inferred internal consistency and repeatability of the LCTFT in sensing contraction responses of HaCaT cells in a concentration dependent manner of TGF-β1. The overall LCTFT and CTFM software had shown good potential for use in the study of contraction and migration of keratinocytes.
6
Harden, John E. "Electro-Mechanical Couplings in Liquid Crystals." Kent State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=kent1239305653.
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7
Hnatenko, O. S., M. V. Neofitnyy, Yu P. Machekhin, V. I. Zarytskyi, and Yu V. Zhdanova. "1,55 mkm fiber laser with electronic controlled mode-locking." Thesis, CAOL, 2019. http://openarchive.nure.ua/handle/document/15099.
Повний текст джерелаАнотація:
A projection of an erbium-doped active-fiber laser is offered in this research paper. Mode synchronization method - the nonlinear evolution of mode polarization, is used to ensure the duration of femtosecond pulses. The basis of this method uses liquid crystal controllers polarization, which is controlled by an electrical signal. The proposed scheme and method for obtaining ultrashort pulses are free from the unstable operation of the laser.
8
Jang, Yong-Kyu. "ADVANCED UNDERSTANDING OF THE OPTICAL PROPERTIES IN PHASE COMPENSATED LIQUID CRYSTAL DEVICES." Kent State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=kent1185484614.
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9
Huang, Yung-Chou, and 黃永州. "Study of Bistable Liquid Crystal Cell." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/81426525865902112353.
Повний текст джерелаАнотація:
碩士明新科技大學
電子工程研究所
97
In this study, we investigated the bistable effect of the bistable liquid crystal cell by different alignment technologies and process parameters. We treated the alignment layer by rubbing-alignment and photo-alignment methods and changed the process parameters to get the bistable liquid crystal cell with the high – low pre-tilt angle and strong-weak anchoring energy. In the study subject 1, we change the monomer contain ratio and the exposure energy in the photo-sensitive material S46 for studying the pre-tilt angle and anchoring energy of liquid crystal cell, then use them for strong-weak anchoring energy layers for bistable liquid crystal cell. In the study subject 2, in order to having a combination of strong and weak alignment layer in the bistable liquid crystal cell, the upper substrate is treated by rubbing process, and the lower substrate of photo sensitive polymer material S46 is treated by photo-aligned process. In addition, we drive the bistable liquid crystal cell using four driving signals to study bitable phenomenon of cell. The experimental results of the subject 1 reveal a best performance as the anchoring energy of the upper substrate is 7.3×10-5 J/m2 and that of the lower substrate is 1.2×10-5 J/m2. The difference of anchoring energy between the upper and lower substrates has a lager value to obtain better bistable effect of cell. The experimental results of the subject 2 reveal a best performance as the anchoring energy of the upper substrate is 2.13×10-4 J/m2 and that of the lower substrate is 3.0×10-5 J/m2. The difference of anchoring energy between the upper and lower substrates has an appropriate range to obtain the better bistable effect of cell. The bistable effect of the bistable liquid crystal cell with the rubbed and photo-treated alignment layer is better than that of the bistable liquid crystal cell with the photo-treated alignment layer.
10
Hsu, Wei-Ting, and 許維婷. "Methods of Cell Gap Measurement for Liquid Crystal Cells." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/94273821363182426557.
Повний текст джерелаАнотація:
碩士國立成功大學
光電科學與工程研究所
92
In a LCD (liquid crystal display), the cell gap plays an important role in determining its performances, such as brightness, contrast ratio, and response time. In particular, a reflective LCD cell gap is usually smaller than a transmissive LCD one, so a little deviation of the cell gap from the desired one leads to poor performances. During the device fabrication, the LC cell gap may deviate from its designed value. For optimizing the performances of LCDs in the manufacturing process, simple, precise, and fast methods to measure the cell gap is required. This thesis researches the measurement methods of cell gaps of LCDs employed commonly. We establish simple and precise cell-gap measurements of a transmissive twisted nematic LC cell and reflective twisted nematic and non-twisted LC cells. The experimental method we use is to place the LC cell between two polarizers and then rotating the polarizers to get transmittance and reflectance. Accurate cell gap can be obtained by fitting the experiment value with the calculation using Jones Matrix.
11
You, Chang-Feng, and 游長峯. "Liquid crystal-doped liquid electrolytes for dye-sensitized solar cell applications." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/7k7k8u.
Повний текст джерелаАнотація:
博士國立彰化師範大學
光電科技研究所
105
We investigate the effects of liquid crystal (LC) dopant on the power conversion efficiency (PCE) of dye-sensitized solar cell (DSSC). The photovoltaic and electrochemical impedance spectra indicate that minute amounts of LC dopant decrease the short-current density of DSSC because the doped LCs reduce the electrochemical reaction rate between DSSC counter electrode and electrolyte. The doped LC impedes the degradation rates of DSSC because of the interaction between cyano groups of the doped LCs and organic solvent in the liquid electrolyte. Owing to the molecular interaction, the doped LCs increase the viscosity and stability, thereby inhibiting the evaporation rate of the liquid electrolyte. Next, the commercialized LCs are also doped into the DSSC. Results indicate that the polar fluoro groups of the commercialized LCs effectively interact with the cyano groups of the organic solvent in the liquid electrolyte, enhancing the long-term stability of the DSSC but without significantly reducing PCE of the DSSCs. The viscosity of the LC dopant is a key factor that affects the light–to–electrical energy conversion efficiency of the LC-doped DSSC. The short-current density and related PCE of the DSSC is not reduced because of the low viscosity of the doped fluorinated carbon-based LCs.
12
Lin, Chen-yi, and 林承毅. "Design of liquid crystal cell gap measurement system." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/3khfdj.
Повний текст джерелаАнотація:
碩士國立中山大學
光電工程學系研究所
97
This thesis use laser diode, lens, grating, and mirrors to composite the external cavity system to retrieve the thickness of the liquid crystal and its characteristics. This way is different to the traditional way of measure. It has good accuracy on the vertical resolution and the vertical resolution can reach to 0.3μm. At the same time, it can develop the high quality of horizontal resolution. On the basis of the correlation between the cavity length and the wavelength of the semiconductor laser, the system is capable of developing high horizontal resolution of accurate liquid crystal measurements. The horizontal resolution can reach to 40μm. Furthermore, by adding bias on liquid crystal through this system, it expanded more understandings on the influences of bias and induced electric field of the electrodes to the tilting angle of the liquid crystal.
13
Liu, Yu-Chen, and 劉育承. "Measurement of the twist nematic liquid crystal cell." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/55864007158967463295.
Повний текст джерелаАнотація:
碩士國立交通大學
電子物理系所
93
This ellipsometric method does not need to rotate the sample azimuthally. The physical parameters of sample are measured under various linear polarized lights through the numerical fitting to its theoretical model. In addition to the orientation of the first layer of nematic liquid crystal is considered, the total phase retardation and twist angle of twist Nematic Liquid Crystal cell are the physical parameters measured by this method. In our error analysis: the maximum error of these three parameters is . By comparison, our results agree well with that measured by the conventional method of A. Lien. The adiabatic following model is closely analyzed. In our measurements, the condition of adiabatic following model is demonstrated. In the end, we also propose a technique to trace out the polarization state on Poincare sphere in real time.
14
Soon, Chin Fhong, Mansour Youseffi, Nicholas Blagden, Rebecca F. Berends, Lobo Samira Batista, Farideh A. Javid, and Morgan C. T. Denyer. "Characterization and Biocompatibility Study of Nematic and Cholesteryl Liquid Crystals." 2009. http://hdl.handle.net/10454/4854.
Повний текст джерелаАнотація:
noIntensive research in bio-engineering has been conducted in the search for flexible biomaterials that could support cell growth and cells attachment. Flexible synthetic materials that support cell growth without the aid of synthetic extracellular matrix proteins are still rare. Cholesteryl liquid crystal containing cholesteryl moieties may have suitable biological affinity. Human keratinocytes (HaCat) were cultured with a nematic liquid crystal and three cholesteryl liquid crystals of different formulation. Subsequently, the trypan blue dye exclusion assay was used to determine cell viability in the liquid crystals. The two classes of liquid crystal were characterized by Differential Scanning Calorimeter (DSC) and polarizing microscope (POM) to understand the nature of the interface material. The cell viability study in medium containing liquid crystals verified that liquid crystals had no effects on cell viability. However, only the surface of cholesteryl liquid crystal has shown affinity to HaCat cells. In addition, cells continued to proliferate in the presence of liquid crystals without a change of medium for eight days. No sign of exothermic and endothermic activities at 370C were observed from the DSC test results for the three samples. Biological and mechanical test result of the cholesteryl liquid crystals has shown that cholesteryl liquid crystals are non toxic and support cell attachment without extracellular matrix protein at very low elasticity.
15
Chwu, Jong-Wen, and 儲中文. "Cell thinning and quality analysis of liquid crystal displays." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/52710491029456202308.
Повний текст джерелаАнотація:
博士國立清華大學
材料科學工程學系
96
Thinning of liquid crystal display (LCD) panels effectively decreases overall thickness and weight of panels, thereby enhancing the aesthetics and ease of use of portable display devices. The technology is typically carried out after the thin-film transistor (TFT) and color filter (CF) substrates are assembled. The first part of this study presents the thickness of panels etched by HF solution with surface etching defects. Polishing effectively removes these defects from glass. However, polishing a panel is more difficult than polishing glass and a suitable polishing approach is developed. In addition, spin-coating a protective layer above the surface fills the defects and retains optical performance. Unlike polishing, the proposed method applies no pressure to the inner structure in the panel. The second part of the study formulates a new mathematical model of the mechanism of the single-sided lapping machine in the LCD cell thinning process; the model is confirmed experimentally. The model can help to optimize the parameters of the process. In the third part of this study, a novel technology is used in an environmentally friendly process of mechanical thinning. It offers lower surface roughness, a higher cut rate and a lower operating pressure than slurry lapping. The final part of this study develops another novel technology, which provides a higher removal rate, better thickness uniformity and finer surface roughness than slurry lapping. The two novel approaches can produce the TFT-LCD panels that are composed of differently thick TFT and CF substrates. Additionally, they methods are stable and practicable for producing thinning cells.
16
Lin, Jin-Hong, and 林君鴻. "The Study of Polymer Wall in Liquid Crystal Cell." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/88013032592600418845.
Повний текст джерелаАнотація:
碩士國立聯合大學
電機工程學系碩士班
94
The solution of LC and monomer sandwiched between the substrates was irradiated with ultraviolet light through a photo-mask to form the polymer wall. The composite film was obtained by photo-polymerization-induced phase separation using a solution film of LC and monomer. The polymer walls formed in the composite film support the substrates and maintain a constant thickness of he composite film. The results of microscopic observations, used a polarizing microscope and scanning electron microscope analysis. We study fundamental display electro-optic characterization such as ionic effects, response time, and measurements voltage-phase.
17
廖家德. "Homeotropic Alignment of Liquid Crystal Cell by Oblique Evaporation." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/43985441882312713534.
Повний текст джерелаАнотація:
碩士長庚大學
半導體研究所
90
Using non-contact alignment has the advantage that is reducing dust and static electricity from rubbing. Homeotropic alignment of liquid crystal cell by oblique evaporation can obtain high quality alignment uniformity. Finally, reach the high resolution. For LC displays using the tilted homeotropic mode, a uniform and small tilt angle (from 1to 4°)from cell normal is to achieve high contrast ratio, and LC with negative dielectric anisotropy tends to alignment homeotropically on the very same SiO2 surface. The pretilt angle is large for small evaporation angles, and decreases as the evaporation angle increases. For LC with negative dielectric anisotropy, the tilt direction is opposite to the evaporation direction for shallow-angle evaporations. When the thickness of alignment layer was thin, the LC molecule to fall in rank is unstable. On the other hand, the LC molecule to fall in rank is stable, as the thickness of alignment layer was thick.
18
楊雅婷. "Transition in Optical Compensation Bend Mode Liquid Crystal Cell." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/90960254339078379802.
Повний текст джерелаАнотація:
碩士國立彰化師範大學
光電科技研究所
97
We investigate the transition processes of the pi cell by applying external voltages. When the voltage increases, the transition time of the cell from the splay state to the symmetric splay state（Hs state）decreases, but the transition time from the Hs state to the asymmetric splay state（Ha state）increases. The obtained results also reveal that if a high voltage is applied to the cell during the initial stage of the Ha state, the transition time of the cell from the splay state to the bend state will be shortest.
19
王品發. "Stability of a Parallelly Planar-Aligned Liquid Crystal Cell." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/27445045815572623817.
Повний текст джерелаАнотація:
碩士國立交通大學
光電工程系所
92
Study on the stability of a liquid crystal cell is an important issue not only in scientific research but also in LCD technology. In this thesis, we discussed the influences of the light sources of projectors, the ultraviolet light source and the annealing system on liquid crystal cells respectively. Moreover, we analyzed the influences on liquid crystal and polyimide thin film separately. In our experiments, the changes of pretilt angles of liquid crystal cells, UV-Visible absorption spectrum of LC and PI, and FTIR absorption spectrum of LC and PI were treated as the basis of stability. We found that the irradiation of intense light and the higher annealing temperature treatments would accelerate the decay of liquid crystal cells. In addition, we proposed a method to measure the larger pretilt angles of LC cells in our experiments, and also obtained the cell gaps of LC cells.
20
Tseng, Kuo-Chuan, and 曾國銓. "Mueller matrix polarimeter for measuring liquid crystal cell parameters." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/24382680339260879198.
Повний текст джерелаАнотація:
碩士逢甲大學
光電研究所
96
Cell parameters such as cell gap, twist angle and pretilt angle determine the image quality and photoelectric properties of liquid crystal displays (LCDs). This research proposes a Mueller matrix polarimeter base on a dual rotating retarder configuration for measuring cell parameters. Light beam from a red HeNe laser passes first through a fixed polarizer, then through a rotating quarter waveplate, the LC cell to be measured, a rotating quarter waveplate, and finally through a fixed polarizer. The rotation ratio of the two waveplates is 5:1. A detector and a data acquisition board are employed to record the transmitted light intensity as a function of rotation angle. The recorded intensity signal is analyzed by fast Fourier transform technique, and the Mueller matrix elements of the test sample are derived from the calculated Fourier coefficients. Finally, the cell parameters are obtained by comparing the experimental matrix with the theoretical matrix of the LC cell under test. Three different cells were measured with the proposed polarimeter and the rotating polarizer method. The nominal gaps of anti-parallel LC cell, multi-domain vertical alignment LC cell, and 90 degrees twisted nematic LC cell are 4.7 μm, 4.2 μm and 3.5 μm respectively. Experimental results show that the maximum deviation of measured cell gaps is about 0.1 μm, and the deviation of measured twist angle is around one degree。
21
Wu, Yin-Chen, and 吳尹塵. "Study on the alignment of liquid crystal and surface propertiesin a liquid crystal cell doped with POSS nanopartcles." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/46028804227820909288.
Повний текст джерелаАнотація:
碩士中原大學
物理研究所
99
Adding 1 wt % polyhedral oligomeric slisequioxa POSS nanoparticles in the liquid crystals can change the planar alignment of liquid crystal (LC) cell into vertical alignment at the room temperature. In this paper, the alignment properties of POSS at different temperatures were investigated. When the temperature increased, pretilt angle of the POSS-doped LC cell decreased. Once the temperature reached 64.61<sup>。</sup>C, the pretilt angle is 4<sup>。</sup> and the POSS-doped LC cell becomes planar-aligned. From the measurement of the contact angles between the POSS-doped liquid crystals and the alignment layer, and the relationship between contact angle and surface energy, we conclude that the decrease of the pretilt angle as the temperature increases is the result of the increase of the surface energy.
22
Lin, Wei-Chih, and 林威志. "A Polarization-independent Liquid Crystal Phase Modulation Using Polymer-Network Liquid Crystals in a 90 Degree Twisted Cell." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/50085568089971352060.
Повний текст джерелаАнотація:
碩士國立交通大學
光電工程系所
97
A polarization independent liquid crystal (LC) phase modulation using polymer-network liquid crystal in a 90 degree twisted cell (T-PNLC) is demonstrated. Two polarization-independent mechanisms are adopted. The first one is the phase modulation from the middle layer LC directors with random but same tilt orientations and can be classified as the residual phase type. The other one is the phase modulation from the directors near the two substrates with nearly orthogonal orientations and can be classified as the double-layered type. T-PNLC is a scattering-free phase modulator because of large domain size (~10μm) and small polymer grain (~0.2μm) observed by SEM. No bias voltage is needed when we operate T-PNLC. The phase modulation range is between the residual phase type and the double-layered type. In addition, the polarization dependency of T-PNLC depends on the effects of the curing voltage, the curing temperature, the cell gap, and off-angle of an incident light. In the experiments, the maximum phase shift of T-PNLC is around 0.28π at 30 Vrms with the cell gap as 7 μm. The response time is around 1.5 msec. The average pretilt angle of liquid crystal in double-layered region(50~70 degree), residual phase region (73~83 degree), and other parameters can be estimated base on our optical analysis of T-PNLC. The potential applications of the polarization independent T-PNLC are electrically tunable-focus LC micro-lens arrays and laser beam steering.
23
Soon, Chin Fhong, K. S. Tee, Mansour Youseffi, and Morgan C. T. Denyer. "Tracking Traction Force Changes of Single Cells on the Liquid Crystal Surface." 2014. http://hdl.handle.net/10454/8562.
Повний текст джерелаАнотація:
YesCell migration is a key contributor to wound repair. This study presents findings indicating that the liquid crystal based cell traction force transducer (LCTFT) system can be used in conjunction with a bespoke cell traction force mapping (CTFM) software to monitor cell/surface traction forces from quiescent state in real time. In this study, time-lapse photo microscopy allowed cell induced deformations in liquid crystal coated substrates to be monitored and analyzed. The results indicated that the system could be used to monitor the generation of cell/surface forces in an initially quiescent cell, as it migrated over the culture substrate, via multiple points of contact between the cell and the surface. Future application of this system is the real-time assaying of the pharmacological effects of cytokines on the mechanics of cell migration.
24
Chen, Hui-Yu, and 陳惠玉. "Electrodynamic Investigations of Ion Charge Transport in Liquid-Crystal Cell." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/83746054331274018085.
Повний текст джерелаАнотація:
博士中原大學
應用物理研究所
95
Two current bumps are shown on the curve of the transient current after reversing the polarity of an external field in this thesis firstly. To explain this two-peak phenomenon of the transient current, which was not observed in previous studies, a modification theoretical model has been explored. By detecting the transient transmission of the light intensity and the response of the transient current at the same time at the onset of flipping the polarity of the external field and with raising the temperature around the liquid crystal cell from nematic to isotropic phase, these two current peaks can be distinguished. The experimental evidence exhibits that they are not only originated from ion transport, but also originated from reorientation of the liquid-crystal molecules, which gathers a dramatic change in the effective dielectric constant as well as the phase retardation. This reorientation phenomenon of the liquid-crystal director is caused by ion screening effect in the nematic liquid-crystal cell. Initially, the ions are free and distribute uniformly in the liquid-crystal layer and the orientation of the liquid-crystal director is dominated by the alignment layer. When an external field (i.e. prefield) is applied on the cell and it is greater than the threshold electric field, the liquid-crystal director tends to be parallel with the direction of the effective electric field across the cell. Meanwhile, the positive and negative ions move to the electrodes with appositive electric properties and then are trapped (adsorbed) on the interface of the alignment layers. As time goes, more and more ions accumulate on there and form an internal field to reduce the effective electric field across the cell. Hence, the orientation of the liquid-crystal director relaxes back to parallel with the substrates again when the effective voltage is reduced to smaller than the threshold voltage. When the polarity of the external field is reversed, at the onset, the effective electric field across the cell is enhanced, due to coincidence of the internal and external fields. Meanwhile, the liquid-crystal director reorients to parallel with the field again, and then it induces an obvious current peak on the curve of the transient current. From the theoretical model developed in this thesis, the behavior of the transient current as well as reorientation of the liquid-crystal director is dominated by the mobility, density and coverage of ions. Moreover, the theoretical model and the experimental technique help for discussing the influence of doping carbon nanotube into the nematic mixture on the ion effect. Compared the behaviors of the transient current of carbon-nanotube-doped cell and pristine cell in a bipolar field, the density and/or coverage of ions are/is suppressed by doping carbon nanotubes into liquid-crystal host. The influence of carbon nanotube on the physical parameters of liquid-crystal mixtures also has been discussed in this thesis. We find that, due to decrease in order parameter, the rotational viscosity and even dielectric anisotropy are reduced in the doped cell. These experimental evidences are helpful for explaining the electro-optical characterize in the carbon-nanotube-doped cell.
25
Huang, Tzu-Yang, and 黃子洋. "Dynamic analysis of ionic charge in the liquid crystal cell." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/54837471726420673897.
Повний текст джерелаАнотація:
碩士國立交通大學
影像與生醫光電研究所
99
In this work, we use LabVIEW to control both of a heterodyne interferometer and a data acquisition system. The phase retardation and transient current of the liquid crystal cells are measured simultaneously for analyzing the dynamic behavior of ionic charges. The dynamic rotation of liquid crystal molecules can be determined by measuring the change of phase retardation and the rotation-induced transient current. The LC parameters, such as effective title angle, effective dielectric constant of liquid crystal, ionic charge density and ion mobility, can be calculated from the measured data. The discrepancy of ion density determined from the phase retardation and transient current is compared and discussed in this work.
26
Kao, Kuan-Chin, and 高冠勤. "Electro-optical Characteristics of Polymer Induced HAN Liquid Crystal Cell." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/8ks77r.
Повний текст джерелаАнотація:
碩士國立臺北科技大學
光電工程系研究所
98
A hybrid aligned nematic liquid crystal (HAN-LC) cell is a potential candidate for display applications because of its features of low operation voltage, fast response time and easy fabrication process. In the conventional HAN-LC cell, the planar and homeotropic alignment films are respectively coated on the top and bottom substrates that the directors of LC molecules linearly vary from perpendicular to one of the two substrates to parallel to the other. In this study, a polymer stabilized (PS) HAN-LC cell is created by doping photocurable monomer in the cell. In our proposed PS-HAN-LC cell, only one substrate is coated with planar alignment film and the other is ITO surface. After the photocuring process, the formation of polymers has the effect on creating homeotropic molecular alignment on the ITO surface and increasing the pretilted angle of the LC molecules on the substrate with planar alignment film. The effect of LC/monomer mixture concentration on molecular configuration and electro-optical characteristics of the PS-HAN-LC cells are described by observing the microscopic textures and scanning electron microscopic textures, and measuring the voltage-dependence transmittance (T-V) curve, response time, phase retardation, viewing angle, and contact angle of substrate surface. The electro-optical characteristics of the HAN-LC cells are also simulated using commercial available software DIMOS to verify those of experimental results. In addition, the effect residual ionic charge which is one of the problems in the LC cell with alignment films on the electro-optical characteristics of the PS-HAN-LC cell is discussed and compared with those of the conventional HAN-LC cells.
27
Huang, Ren-Hung, and 黃仁宏. "Linear gray level adjustment for a ferroelectric liquid crystal cell." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/hwjf9x.
Повний текст джерелаАнотація:
碩士國立臺北科技大學
光電工程系所
93
A ferroelectric liquid crystal (FLC) cell can be modeled as a combination of capacitors and resistors. In accordance with the properties of the FLC cell, external electric elements, such as capacitors and resistors, are usually connected to achieve a V-shaped performance at a driving inversion frequency . However, the inversion frequency is strongly dependent on the external electric elements and the applied voltage. The relation between an external capacitor and the profile of the V-shape is discussed through a voltage divider across the ferroelectric liquid crystal cell. An optimized circuit is demonstrated to alter the profile of the V-shaped electro-optical transmittance and raise the characteristic frequency so that the linear gray levels can be modulated in a wide range of applied voltage. On the other hand, we study the vertical alignment for a ferroelectric liquid crystal that has fast response, high contrast, and analog gray scale capability. In contrast to the conventional rubbing alignment in a planar geometry, smectic layers arrange themselves parallel to the substrates, and thus extremely uniform alignment of molecules in large area is naturally achieved.
28
Wang, Po-Hsuan, and 王博玄. "Muti-Wavelength Mueller Matrix Polarimeter for Measuring Liquid Crystal Cell Parameters." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/57793397723630207413.
Повний текст джерелаАнотація:
碩士逢甲大學
光電研究所
97
The parameters of liquid crystal displays (LCDs), such as cell gap, twisted angle, and pretilt angle, greatly affect the brightness, contrast, and respond time of LCDs. These parameters could be accurately determined by polarimetry because LC layer is the only birefringent film in a LCD. This study proposes a muti-wavelength Mueller matrix polarimeter, using the dual-rotating-retarder technique, for measuring the LCD parameters. The proposed method provides several benefits over other polarimetric and interferometric methods: the unambiguous range of phase retardation is extended, more cell parameters are derived from the recorded intensity variation, and the systematic error can be removed by a self-calibration step. Three different types of LC cells were investigated and the results are presented in this study.
29
林晴祥. "Effect of rubbing strength on the orientation of liquid crystal cell." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/24591554391436321568.
Повний текст джерелаАнотація:
碩士國立彰化師範大學
光電科技研究所
94
This thesis studies the relationship between the surface of the substrate and the parameter of the LC cell. The measured results indicate that the pretilt angle of the LC cell increase initially, and then decrease with increasing rubbing times. This is resulted from the surface roughness of the substrate. The measured birefringence increases with increasing rubbing times, due to the unidirectionl alignment of the polymer chain by velvet rubbing. The polar anchoring coefficient is independent on the rubbing time.
30
潘鴻至. "Electrooptical behavior of carbon nanothube doped twisted nematic liquid crystal cell." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/18504123230264437230.
Повний текст джерелаАнотація:
碩士國立彰化師範大學
光電科技研究所
94
We investigated the electrooptical responses of the carbon nanotube doped liquid crystal cells. The cells were constructed in the twisted geometry and doped with various amount of carbon nanotubes. Experimental results revealed that the doped carbon nanotubes influence the dielectric anisotropy and elastic constant of the liquid crystal carbon nanotube mixture. The carbon nanotube dopant was found significantly improve electrooptical responses of the liquid crystal cell. Additionally, the dc measurement indicates that the hysteresis in the transmission versus applied dc voltage curve of the cell is reduced when CNTs are doped into the LC mixture.
31
Kou, Hsiao-Ti, and 苟孝第. "Study on Asymmetric Optical Response of Twist Nematic Liquid Crystal Cell." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/v9qbq5.
Повний текст джерелаАнотація:
碩士國立臺北科技大學
光電工程系研究所
98
Nowadays, liquid crystal display (LCD) has been widely used in many kinds of electronic products. But some defects such as voltage holding ration (VHR), flicker, and image-sticking effect are usually produced in LCD that reduces the display performance. These defects have extensively been discussed and researched upon the ionic effect. In this study, the asymmetric electro-optical properties of twist nematic LCD are investigated based on the ionic effect. First, a model of intrinsic electric field and formulas are proposed to discuss the asymmetric VHR in TN-LCD. We confirm that the asymmetric VHR is caused due to the existence of intrinsic electric field in the LCD. The direction of intrinsic electric field is independent of the polarity of external applied voltage. On the other hand, we discuss the ionic effect in the LCD with a backlight irradiating to the cell. Two kinds of light source, Cold Cathode Fluorescent Lamp (CCFL), and ultraviolet light are used in this study. While irradiating backlight to the LCD for a long time, some optical responses of LCD are changed. We observe these changes by controlling the irradiating time of backlight. According to the observation of microscopic textures, the changes of optical response of LCD as a function of irradiating time of backlight is suggested to relate to the ionic effect. The relation between the ionic effect and optical response of LCD is clarified, so as to explain the formation of defects in LCD.
32
Lo, Li, and 羅立. "Method of Alignment of Ferroelectric Liquid Crystal Cell without Alignment Layer." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/6sfn7z.
Повний текст джерелаАнотація:
碩士國立臺北科技大學
光電工程系研究所
99
We present an electric field treatment method in ferroelectric liquid crystal cell without alignment layer that enable the uniform molecular orientation to be obtained in the planar aligned ferroelectric liquid crystal (FLC) cell. In this method, we used the FLC materials showing N*-SmA-SmC* phase sequence, the molecular orientation is changed from planar to homeotropic state in the SmA phase by the application of electric field due to the dielectric coupling. After the treatment of electric field, the smectic layers are initially formed parallel to the substrate plane in the SmA phase, leading to the stable homeotropic state. To reduce the voltage that reached homeotropic state, we also have successfully use this method in N* phase. And the effect of electric field conditions such as the frequency, amplitude, and the duration of the electric field applied to the cell on the uniformity of alignment of the cell is clarified. In addition, the cell treated with electric field applied through N*-SmA or N*-SmA-SmC* phase transition shows more uniform alignment than that cell treated with electric field in the SmA phase. At last, in order to apply the technique to flexible display, we used Polymer to stabilized the ferroelectric liquid crystal cell. We also discussed the impact of Polymer concentration on uniform molecule orientation and the impact of changing the temperature of curing Polymer on homeotropic state.
33
Dong, Guan-Ting, and 董冠廷. "Surface Plasmon Assisted Transient Transmission Effect in Photosensitive Liquid Crystal Cell." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/54vwr4.
Повний текст джерелаАнотація:
碩士國立中山大學
光電工程學系研究所
106
Surface plasmon resonance (SPR) is sensitive to the surface structure, metal properties and refractive index of the upper layer. Liquid crystal is anisotropic material. In optics, the refractive index varies with the direction of the light entering the liquid crystal. 5CB liquid crystal doped with 1205 azo-dyes is used in the experiment. The azo-LC layer could be switched between isotropic and nematic phases by irradiating with UV laser or green laser. Liquid crystal micro domains (formed between isotropic and nematic phases) were generated during phase transition process. These micro domains caused Mie scattering. In this research, we injected the azo-LC into a liquid crystal cell with aluminum metallic grating, and used 1205 azo-LC as a switch to control the coupled of surface plasmon resonance. During the phase change process of azo-LC, the micro particles appears in the azo-LC layer. And this micro particles caused Mie scattering effect to the incident light. The Mie scattering effect to the incident light provides much horizontal k-vectors on metal surface and increases the probability for the light to couple the surface plasmon resonance.
34
Chiou, Chung-Chin, and 邱崇欽. "Flexible Polymer Dispersed Liquid Crystal Cell based on Novel Transparent Electrodes." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/j4znuk.
Повний текст джерелаАнотація:
碩士國立交通大學
光電工程研究所
106
In this thesis, we demonstrate the fabrications and characterizations of flexible polymer dispersed liquid crystals (PDLC) cell with novel transparent electrode, including multilayer structure (TiO2/Ag/TiO2) and graphene layers as transparent conductive electrodes (TCE). The cell is formed by a PDLC layer sandwiched with two flexible polyethylene terephthalate (PET) substrates with TCE layers. The PDLC is composite layer that consists of submicron-size droplets of liquid crystal randomly dispersed in a polymer matrix. Its transmission can be modulated by applying an external voltage on the TCE. Thus, we have studied the modulation characteristics of each device to evaluate those TCE films for applications on flexible optoelectronic device. For preparation of flexible substrate with TiO2/Ag/TiO2, we deposited three layers on PET by using the Radio Frequency (RF) magnetron sputtering technique on PET at low temperature (40-60℃). Meanwhile, flexible substrate with graphene is obtained by transferring the graphene thin film, which is grown on copper foil by low pressure CVD method, onto a 100-m thick PET film. Several measurements have been conducted to characterize those substrates. First, the SEM microscope is performed to study the surface structure of the thin film. Second, the sheet resistance of substrate is taken by a 4-point probe platform and then transmittance spectrum of substrate is taken by a spectrometer. In addition, the flexibility of the substrate is conducted by using a homemade bending testbed. With these results, we can make figure of merit to select the best substrate for fabricating PDLC device. Thus, after preparation of those devices, the transmittance dependence on the driving voltage and response time of each device are measured and discussed.
35
Liu, Che-Cheng, and 劉哲誠. "Study of line filling process for flexible cholesteric liquid crystal cell." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/60681946110626367831.
Повний текст джерелаАнотація:
碩士南台科技大學
光電工程系
97
The glass substrate is the main material used in current LCD display. Flexible display shows the potential application for next generation of display application, because the plastic material has the advantages on the weight and flexibility. Moreover, flexible displays can be designed for various electronic products such as electronic book, electronic paper and electronic board etc. At any aspects, the plastic substrate will substitute the glass material, and then leads the process evolution from sheet-feed Batch process to Roll-to-Roll process. In this study, we fabricated the flexible cholesteric liquid crystal cell by using a roller pressing unit to laminate two PET substrates. Cholesteric liquid crystal had high viscosity, so that the flowability was limited. Therefore, it had high percentage to form bubbles in the cell. In order to enhance the surface energy and wetability properties and reduce bubbles in the cell, we use O2 plasma to modify the surface of ITO coated PET substrate. The influence of treatment on the surface properties of PET were investigated by contact angle and atomic force microscopy (AFM). Experimental results revealed that the cell formed from the untreated substrate had bubbles at substrate speed of 5mm/sec. This result is attributed to the poor wetability and low surface energy. However, adding external load can enhance the substrate lamination speed. In contrary to the untreated substrate, O2 plasma treated substrates had good wetability and high surface energy so that it could improve the anchoring of liquid crystal on the surface. At the speed of 30mm/sec, there was no bubble in the cell. As the lamination speed was increased, the external load was the key factor to influence the flowability of LC. Under the optimized condition, the substrate lamination speed would reach 40mm/sec. The cell had good optical property with O2 plasma treated surface and the cell deviation of reflectance could be minimized.
36
Zhang, Ji-Hong, and 張繼鴻. "A voltage controlled lens formed in a nematic liquid crystal cell." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/5x873b.
Повний текст джерелаАнотація:
碩士中原大學
應用物理研究所
91
A liquid crystal lens is prepared with two layers of nematic liquid crystal cells. These two layers of nematic liquid crystal cells are homogeneous alignment and the directors are perpendicularly each other. The ITO glass is etched to form a hole-patterned electrode. The curved electric field results the directors are reoriented easily at exterior and gradually difficult in approaching the center. The focal length is variable and is function of applied voltage. In our device, the two perpendicular alignments of two cells can compensate the difference of optical path length, when the incident light has different polarization. The experimental results are conformed to theory.
37
Kuo, Yu-Ping, and 郭玉苹. "Photo-alignment for an Optically Compensated Bend Mode Liquid Crystal Cell." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/02645578327305091529.
Повний текст джерелаАнотація:
碩士國立臺北科技大學
光電技術研究所
92
OCB (Optically Compensated Bend) mode LCD is promising as the next generation display, due to its symmetry on cell’s top and bottom, and especially its fast response and wide viewing angle. However this mode has intrinsically some problems: Firstly, it has long warm up time. It takes long time to shift from splay alignment to bend alignment because it stays on splay alignment at initial state. Secondly, it needs high critical voltage, high energy barrier must be overcome, to shift from splay alignment to bend alignment. Thirdly, bend configuration at low driving field is unstable. This study employs some mixture of liquid crystal and monomer. In order to produce high pretilt angle, high voltage,Vuv, is required to apply on cells as being irradiated by UV light. At this time liquid crystal molecules align with polymer, so the cell has high pretilt angle. By this way we can reduce critical voltage,Vs-b, at witch splay alignment transfers to bend alignment. After UV curing, the OCB cell sometimes becomes a homogeneous aligned cell. In summary we succeed in: (1) using electric voltage to control pretilt angles. (2) adding monomer to break energy barrier thus to reduce Vs-b (3) finding the optimum combination as one kind of monomer F at 1wt% Vuv=3.4V and Vuv=5.6V.(4) after UV curing, the OCB cell sometimes becomes a homogeneous aligned cell.
38
林年青. "Study on the Optically Compensated Bend (OCB) Mode Liquid Crystal Cell." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/23910532781510590862.
Повний текст джерелаАнотація:
碩士國立臺北科技大學
光電技術研究所
92
Liquid crystal displays (LCDs) employ the rotation of liquid crystal (LC) molecule to control the transmittance of display. If there is no technology of wide view angle, LCDs will have the defect of narrow view angle. If we develop large-sized LCD monitors in the future, the defect of narrow view angle will be obvious. OCB (Optically Compensated Bend) mode is also a technology of wide view angle of LCDs. Besides increasing view angle, OCB mode LCDs have fast response time as well. In this study, we added a small amount of UV curable monomer to the LC material and the mixture was cured with an applied voltage across the cell. We changed the mixed ratio of LC and monomers, the amplitude of applied voltage, and the time of curing UV. We adjusted the three parameters and made them optimal. Finally, we finished the OCB mode LCD with fast response. With optical response system, we were able to measure the response time of our OCB mode LC cell in less than 7 ms.
39
Soon, Chin Fhong, K. S. Tee, Mansour Youseffi, and Morgan C. T. Denyer. "Compressive forces of cell induced longitudinal deformation to the liquid crystal surface." 2015. http://hdl.handle.net/10454/9226.
Повний текст джерелаАнотація:
NoThe ability of a cell to contract plays an important role in determining the ability of the cell to migrate, proliferate and associating with other cells. The transduction of the force in soft substrate such as the liquid crystal surface is a method proposed to study the traction forces of single cells. In this work, finite element method was used to study the compressive forces induced by the keratinocyte to the liquid crystal surface via the anchorage of focal contacts. The constitutive finite element model of the liquid crystal-focal contacts was established. The stress and displacement were analyzed using linear static stress analysis for a quiescent cell. The data for lateral displacements obtained from the experiment were provided as inputs to develop the model and verified through the output acquired for both simulation and experiment. The simulation results indicated that the cell compressive stresses were in the range of 14.93 ± 1.9 nN/μm2 per focal contact. Based on the result obtained, it was suggested to model focal contact-liquid crystal interface with a compressive model that can better approximate the mechanism observed
40
Tsai, Sin-Yan, and 蔡欣言. "The relationship between the Kerr constant and cell thickness in blue phase liquid crystal cells." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/a5989c.
Повний текст джерелаАнотація:
碩士國立臺北科技大學
光電工程系研究所
102
Blue phase liquid crystal ( BPLC ) has a double helical cylinder lattice structure. The electro-optical mechanism of BPLC is the electric-field-induced birefringence, δn, known as the Kerr effect. In this study, we experimented and discussed the relation between the Kerr constant and cell thickness. The result is an important reference for BPLC electro-optical property, and may have a great help for applications of BPLC in the future. In this paper, we changed the thickness of the cell and drove it by vertical electric field. The BPLC cells were placed in 45? and 60? with respect to the incident light. Measuring the relationship between the phase retardation φ and driving voltage V, and using the φ - V relation, we obtained the induced birefringence δn. Finally, we obtained that the δn is proportional to E^2. The results match the Kerr effect formula. Kerr constant is calculated, and we found that the cell thickness will affect the Kerr constant.
41
Chen, Po-An, and 陳柏安. "Residual Direct Current Voltages and Intra-Cell Ionic Properties of Twisted Nematic Liquid Crystal Cells." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/7zwxxj.
Повний текст джерелаАнотація:
博士國立交通大學
光電系統博士學位學程
107
The presence of impurity ions in liquid-crystal displays (LCDs) is one of the nuisances that affect the display qualities such as threshold voltage, voltage holding ratio, flicker and image sticking. In this thesis, we report the ionic effects on electro-optics and residual direct current voltages (VrDCs) of two PI-aligned TN cells with same LC mixture but different PI-alignment materials. We have also carried out new experimental methods to find out that the observed VrDCs are caused by LC-PI-interfacial (IF) trapped ions generated and transported from the LC medium for one of TN cells, and from the PI layers for the other TN cell. Our measured VrDCs indicate that the former has two different exponential-decay rates similar to the published results by M. Mizusaki et al. [chap.3 ref. 3], but the latter has only a single exponential-decay rate. In this thesis, we also report our investigation of intra-cell ionic properties of two TN LC cells made of same LC mixture but different PI-alignment materials. By using an LCR meter, a heterodyne interferometry, and a current meter, we have measured the data of capacitance versus voltage from 1 kHz to 100 kHz, the phase retardation versus voltage at 1 kHz, and the phase retardation versus time and the current versus time by applying a mid-grayscale voltage of 1.3 V at 0.1 Hz on the two TN cells. Related to the above measured data, we have developed equations to characterize the field-driven transports of mobile charge carriers within the PI films independently from that within the LC medium of same TN cell to obtain the time-dependent ionic-charge voltages caused by accumulated charges on the proximities of LC-PI interfaces originated either from LC side or from PI sides, respectively. Our experimental methods provide promising possibilities by further investigations to find out the origins and the chemical structures of impurity ions, as well as mobile-charge-carrier activation energy, mobility, ion concentration…etc. within thin in-cell PI-alignment films independently from within the LC mixture of the same LC cell. Furthermore, we believe that the methods presented in this thesis can be applied to select and optimize LC mixtures and PI materials to accomplish low-refresh-rate thin-film-transistor-driven LCDs leading to the realization of always-on displays.
42
Chow, Liansing, and 周蓮馨. "The study of Transition free Liquid Crystal Reactive Monomer Modified OCB Cell." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/60111615887335437814.
Повний текст джерелаАнотація:
碩士國立交通大學
顯示科技研究所
96
In the newly 21th century, the giant super computer in the 20th century has been replaced by small and tiny notebooks or super thin computers. The CRT screen has been replaced by liquid crystal screen with a characteristic that very thin, very small, very light, and moreover, very short. The liquid crystal screen has a distinguishing feature that it responses to the electric field with different reactions. Accompany with different kind of liquid crystals be presented to the public, and some deficiencies with different kind of liquid crystal, like response time and the quality of the moving images, it becomes a new target to the researchers. Among those different kinds of liquid crystals, optically compensated bend, also known as OCB cell or Pi cell, has a characteristic that its response time is fast and has high contrast ratio. OCB cell was operated at bend and vertical state, and also known has a big deficiency that it needs a voltage bigger than the critical voltage to have the splay state become the bend state, also called as transition. In this thesis, we will discuss how to use a new material to operate with the original OCB cell and form the OCB cell in a condition without transition and still has the advantages of the original OCB cell.
43
Tsung-TseYang and 楊宗澤. "Extracting Optical Parameters of a Liquid Crystal Cell by Using Stokes Polarimetry." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/88765082506562998877.
Повний текст джерела
44
Wu, Hsin Cheng, and 吳昕澄. "Liquid crystal polymer coatings for improved efficiency of Dye-Sensitized Solar Cell." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/29542922296259721862.
Повний текст джерелаАнотація:
碩士長庚大學
光電工程研究所
101
We proposed a high efficient dye sensitize solar cell (DSSC) with multi-layer structure, using liquid crystal polymer (LCP) coating small nano-particle size (21nm) has large contact area to absorb more dyes. Liquid crystal polymer precursor solutions of six different concentrations ( 1%, 2%, 5%, 7%, 10%, 15% ) of liquid crystal polymer(LCP) were coated and cured on the working electrodes as a light-leading layer. The light-leading occurs because the properties of birefringence with LCP. And the light-leading can lead solar light in the electrolytes back to the TiO2 ,which means we have more optical path length in the solar cell, and the phenomenon can increase light-trapping efficiency of N719 dye. Thus the efficiency of DSSC will be higher. The experiment results shows that the DSSC with the liquid crystal polymer (LCP) concentration of 10% exhibited the best optic electric conversion efficiency, which is 4.55%. It was improved by 33.8% when compared with the control cell sample.
45
Cai, Shih-guo, and 蔡世國. "Cell gap measurement of liquid crystal displays by scanning white light interferometer." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/82930554864136432480.
Повний текст джерелаАнотація:
碩士逢甲大學
光電研究所
95
The cell gap of a liquid crystal display (LCD) determines the LCD’s image quality and photoelectric characteristic. This research proposes a scanning white light interferometer (SWLI), based on low coherence tandem interferometry, for measuring the liquid crystal (LC) cell gap. The theoretical model is simple, and no time-consuming library matching is required. The SWLI consists of a white light source, a scanning Michelson interferometer (SMI), and a LC cell. The SMI and LC cell are in tandem and thus can prevent the dispersion error caused by the upper glass of the LC cell. The light is first directed to the SMI. Then a beam splitter divides the output beams of the SMI into two parts. One part is collected by a reference detector. The other part is incident on the LC cell, and the reflection from the cell is received by the measuring detector. The optical path difference of the SMI is continuously changed and the output signals of the detectors are recorded. The normalized reference signal is subtracted from the normalized measuring signal to reduce the influence of the central white light fringe, which is always generated when the path difference in the SMI is zero. After zero-order interference fringes are identified with centroid algorithm, the cell gap is directly determined from the separation between these fringes. Three different cells were measured with the SWLI. The nominal gaps of empty cell, twisted nematic (TN) cell, and multi-domain vertical alignment (MVA) cell are 5 μm, 3.5 μm, and 4.2 μm, respectively. Experimental results show that the deviation is about 0.1 μm for the empty cell, and the deviation for the other two cells is 0.4~0.5 μm。
46
Chang, Wei-Yao, and 張巍耀. "Study of Measuring the Nematic Liquid Crystal Cell Parameters with Heterodyne Interferometry." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/82256916613648981077.
Повний текст джерелаАнотація:
碩士逢甲大學
電機工程所
97
Nematic liquid crystal cells are widely applied in liquid crystal displays (LCDs) and related electro-optical devices. The cell parameters, such as the pretilt angle, cell gap and polar anchoring strength, directly affect the quality and performance of products. Therefore, this work presents a simple method to simultaneously determine the pretilt angle and cell gap of nematic liquid crystal cells. The phase retardation of nematic liquid crystal cells can be measured precisely by the heterodyne interferometry with only two appropriate incident angles. Then, the pretilt angle and cell gap can be determined. In experiment, the cells with pretilt angles in different ranges were measured, including a homogeneously aligned cell, a vertically aligned cell, and a liquid crtstal cell with an intermediate pretilt angle in the range of 30�{60�a. The measured results are in good agreement with the reference data which were measured using the commercial Mueller matrix polorimeter. Furthermore, with the same setup, the polar anchoring strength of homogeneously aligned cell was measured by applying voltages to the cell. The characteristics were also simulated with DIMOS software. The proposed method has the advantages of simplicity of installation, ease of operation, high stability, high accuracy, and high resolution. In particular, this method has no restriction on the range of pretilt angle.
47
Liou, Pin-Ze, and 劉品澤. "Study on the Alignment Methods of a Twist Ferroelectric Liquid Crystal Cell." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/777vhz.
Повний текст джерелаАнотація:
碩士國立臺北科技大學
光電工程系研究所
99
We develop the surface stabilized ferroelectric liquid crystal (SSFLC) alignment methods in the twist FLC cell. FLC materials are R2301, CS2005 and R3206. In the study, we investigate the effect of surface rubbing treatment and electric field treatment for the twist FLC molecular alignment. The R2301 cell with reverse rubbing 52° shows the mono-domain alignment, because the twist angle is the cone angle, and the Ps direction meets with the surface polarity of PI, making the layer structure continuously. On the other hand, the R2301 cell with rubbing 52° shows the two domain defects, owing to the discontinuous layer structure. In addition, the CS2005 and R3206 cells that rubbed at the cone angle can’t show uniform alignment. We think CS2005 possess large Ps and large cone angle, which cause the molecular aligned irregularly. For the R3206 cell, the pitch is too short to obtain the uniform alignment. The R2301 cell that coated with different polarity polyimide (PI) and rubbed 90° shows uniform alignment by electric field treatment. At the substrate surfaces, the Ps directions are parallel to the PI polarity and the molecular directors are parallel to the transmission axis of the polarizer or analyzer. The CS2005 cell shows uniform alignment at the best condition of 10V-1Hz. For the R3206 cell, due to short pitch, the alignment is still not improved by the electric field treatment. According to the T-V curve, the CS2005 cell with 90° rubbing shows better electro-optical properities than the other cells. As a result, the twist FLC cells possess fast response characteristics and high contrast ratio.
48
Chang, Jun-Ren, and 張俊仁. "Photo-alignment for a Multi-Domain Vertically Aligned Mode Liquid Crystal Cell." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/886f7g.
Повний текст джерелаАнотація:
碩士國立臺北科技大學
光電工程系所
93
The technology of multi-domain vertical alignment owns many advantages like high contrast ratio and wide viewing angle. The present technology of multi-domain vertical alignment manufactures bumps to control the alignment of liquid crystal and has the shortcoming of asynchronous liquid crystal alignment. In this thesis, an improved technology of multi-domain vertical alignment is presented. The technology of polymer-stabilized alignment is employed to manufacture the LC cell and then the optical and electrical characteristics of the LC cell are measured. We use the mixture of monomer and liquid crystal, illuminated with ultraviolet to form the polymer network which can control the alignment of liquid crystal molecules. In UV illumination process, a curing voltage Vuv is applied on the mixture to make the liquid crystal with pretilt angle. In summary we succeed in: (1) Controlling the pretilt angle of liquid crystal by applied voltage. (2) Making a better liquid crystal alignment by forming polymer network. (3) The optimum parameter 1wt% when Vuv=8.5 V and 0.5wt% when Vuv=8.5 V are obtained. (4) The improved LC cell of multi-domain vertical alignment can shorten the response time of liquid crystal. (5) The factories only need to mix little monomers to improve the characteristic of LC cell without changing the manufacturing processes.
49
Chang, Chia-Jen, and 張嘉仁. "Cell Filling Of Flexible Liquid Crystal Display Using Continuous Air-Extracting Method." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/11877022267306248145.
Повний текст джерелаАнотація:
碩士南台科技大學
光電工程系
97
LCD is the most popular of flat-panel display in the market. Now technologies are being developed to achieve large size, thin and flexible LCD displays. The currently used liquid crystal cell filling technology includes one drop filling (ODF) and conventional vacuum siphon method. However, the conventional method is not suitable for large size panel, because it needs long LC filling time. The use of ODF is too expensive and complicated in handling the flexible substrate. Therefore, developing a new LC cell filling method to drive flexible LCD a step forward to commercialization is essential This study uses so-called Continuous Air-Extracting Method to fill liquid crystal cell. This method can conduct liquid crystal filling in atmospheric environment, requiring no long filling time as the conventional method and less expensive than with the ODF method. The cell pressure, cell aperture width, cell flow channel, spacer density, cell tilt angle and cell temperature were varied for obtaining the optimized filling efficiency. The best filling conditions were cell pressure = 2 torr, cell aperture width = 9 mm, symmetrical 1-1 port arrangement, spacer distribution density = 300~400 pcs/mm2, cell tilt angle = 45°. The best filling time of 43 sec at cell temperature = 75℃.
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Soon, Chin Fhong, Mansour Youseffi, Rebecca F. Berends, Nicholas Blagden, and Morgan C. T. Denyer. "Development of a novel liquid crystal based cell traction force transducer system." 2013. http://hdl.handle.net/10454/6199.
Повний текст джерелаАнотація:
Keratinocyte traction forces play a crucial role in wound healing. The aim of this study was to develop a novel cell traction force (CTF) transducer system based on cholesteryl ester liquid crystals (LC). Keratinocytes cultured on LC induced linear and isolated deformation lines in the LC surface. As suggested by the fluorescence staining, the deformation lines appeared to correlate with the forces generated by the contraction of circumferential actin filaments which were transmitted to the LC surface via the focal adhesions. Due to the linear viscoelastic behavior of the LC, Hooke's equation was used to quantify the CTFs by associating Young's modulus of LC to the cell induced stresses and biaxial strain in forming the LC deformation. Young's modulus of the LC was profiled by using spherical indentation and determined at approximately 87.1+/-17.2kPa. A new technique involving cytochalasin-B treatment was used to disrupt the intracellular force generating actin fibers, and consequently the biaxial strain in the LC induced by the cells was determined. Due to the improved sensitivity and spatial resolution ( approximately 1mum) of the LC based CTF transducer, a wide range of CTFs was determined (10-120nN). These were found to be linearly proportional to the length of the deformations. The linear relationship of CTF-deformations was then applied in a bespoke CTF mapping software to estimate CTFs and to map CTF fields. The generated CTF map highlighted distinct distributions and different magnitude of CTFs were revealed for polarized and non-polarized keratinocytes.