Proceedings Volume 6030

ICO20: Display Devices and Systems

Tatsuo Uchida, Xu Liu, Hang Song
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Proceedings Volume 6030

ICO20: Display Devices and Systems

Tatsuo Uchida, Xu Liu, Hang Song
View the digital version of this volume at SPIE Digital Libarary.

Volume Details

Date Published: 11 January 2006
Contents: 1 Sessions, 32 Papers, 0 Presentations
Conference: ICO20:Optical Devices and Instruments 2005
Volume Number: 6030

Table of Contents

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Table of Contents

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  • Display Devices and Systems
Display Devices and Systems
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Fabrication of Si field emitters with a focus electrode
Hidenori Mimura, Yoichiro Neo, Hidetaka Shimawaki
To realize an ultra-fine display for nanovision science, we have studied functional emitters which are capable of stabilizing the emission current or focusing the electron beam. We have developed a field emitter with a vertical type junction field effect transistor (JFET), in which the stability of the emission current is significantly improved, when the JFET is operated as a constant current source. We also developed both field emitters with an in-plain focus electrode and a vertical focus electrode. When the focus electrode is operated, beam spot size is drastically reduced for both the emitters. However, the spot image is distorted for the emitter with an in-plain focus electrode. On the other hand, almost symmetric image is obtained for the emitter with a vertical focus electrode, but the emission current is drastically reduced due to the influence of the low potential of the focus electrode. The use of a thick gate electrode of about 1 μm is effective for preventing the decrease of the emission current.
Large area deposition technique of magnesium oxide thin film for plasma display panel applications
Young-Wook Choi, Jeehyun Kim
A higher rate deposition sputtering process of magnesium oxide thin film in oxide mode has been developed using a 20 kW unipolar pulsed power supply. The power supply was operated at a maximum constant voltage of 500 V and a constant current of 40 A. The frequency and the duty were changed in the ranges of 10 ~ 50 kHz and 10 ~ 60 %, respectively. The deposition rate increased with increasing incident power to the target. Maximum incident power to the magnesium target was obtained by the control of frequency, duty and current. The deposition rate of a moving state was 9 nm m/min at the average power of 1.5 kW. This result shows higher deposition rate than any other previous work of reactive sputtering at the oxide mode. The thickness uniformities over the whole substrate area of 982 mm x 563 mm were observed at the processing pressure of 2.8 ~ 9.5 mTorr. The thickness distribution was improved at lower pressure.
Characteristics of mist 3D screen for projection type electro-holography
Koki Sato, Toshimichi Okumura, Takumi Kanaoka, et al.
The specification of hologram image is the full parallax 3D image. In this case we can get more natural 3D image because focusing and convergence are coincident each other. We try to get practical electro-holography system because for conventional electro-holography the image viewing angle is very small. This is due to the limited display pixel size. Now we are developing new method for large viewing angle by space projection method. White color laser is irradiated to single DMD panel (time shared CGH of RGB three colors). 3D space screen constructed by very small water particle is used to reconstruct the 3D image with large viewing angle by scattering of water particle.
Reconstruction of full-color images with a RGB time-sharing holographic display system
Kunihiro Sato, Atsuhiko Sugita, Masakazu Morimoto, et al.
A time-sharing holographic color display system is developed using a high-resolution reflective liquid-crystal display (LCD) panel that consists of a 1920x1080 array of square pixels with width of 8.1 micron. Red, green and blue images with high resolution are reconstructed from the holographic display system with a low-power red laser diode (LD), a low-power green diode-pumped laser and a low-power blue diode-pumped laser. The reconstructed color image can clearly be observed under the room light. The image exhibits good color expression. Moving 3D color images with high quality are reconstructed from holograms displayed on the LCD panel of the developed holographic system.
Recording and reconstruction of 3D color images of practical objects by phase-shifting holography
Yusuke Hamada, Kunihiro Sato, Masakazu Morimoto, et al.
A phase-shifting holography system for recording 3D color images is developed with a color CCD, and red (R), green (G), and blue (B) lasers. Phase of reference lights in this recording system is precisely shifted by shifting fringe patterns displayed on a high-resolution reflective LCD panel. Color images of the practical object are able to be recorded at the same time as RGB interference fringe patterns by adopting a high-resolution color CCD. Holograms for reconstruction of fine RGB images are obtained from recorded fringe patterns by the phase-shifting holography, and animated high-quality color images of the practical object are reconstructed from the holograms using the developed holographic color display system.
Information reduction in hologram and a 3D display with a movable light source
Shingo Hamada, Kunihiro Sato, Masakazu Morimoto, et al.
The superimposing method is described in order to reduce information in hologram. This method improves loss of resolution and increase of the speckle noise which are caused by the information reduction in the sampling method. Experiments are carried out for reconstruction of images from the computer-generated hologram or from the practical hologram. Results show that high-resolution images with low speckle noise are reconstructed from the continuous periodic hologram with reduced information. The image without visual depth is reconstructed on the Fourier transform plane from the hologram with reduced information, if the bandwidth is taken to be smaller than the diameter of observer's pupil. The visual field is divided into several fields in order to display images with visual depth, and images in divided fields are recorded on several Fourier transform holograms. A time-sharing system with a movable reference light source is developed in order to reconstruct real-time 3D images from several Fourier transform holograms with reduced information.
The effect of NPB morphology on OLEDs optoelectronic characteristics
Yurong Jiang, Zhinong Yu, Wei Xue
N,N'-bis(lnaphthyl)N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine (NPB) surface morphologies deposited on different temperature substrates were investigated using atomic force microscopy(AFM). NPB is an organic materials often used as hole transport layer(HTL) in organic light-emitting devices (OLEDs). It has been found that the NPB morphology turned from island morphology at high temperature(100°C) to grain morphology at room temperature. At the same time, the growth mode of NPB film also changed from the Volmer-Weber type to the Stranski-Krastanov type. The results show the wettability between NPB and ITO becomes worse when the substrate temperature increases, which prevents NPB from forming continuous thin film. To characterize the effect of NPB surface morphology, the devices with the structure of Glass/ITO/NPB/Alq3/Al were fabricated using NPB films deposited at different substrate temperature and their performances were compared. The results show that the NPB morphology has significant effects on the performance of OLEDs.
Design of an improved data signal timing for an amorphous silicon active-matrix organic LED display
Yan-ping Liao, Zhi-wei Zhang, Xi-bin Shao, et al.
The most critical issue in the design of an active matrix organic light emitting diode (AM-OLED) display pixel is the pixel to the pixel luminance uniformity. By substituting four-thin film transistor (TFT) pixel circuit for two-TFT pixel circuit, the luminous uniformity has great improved, but it requires more components than the two-TFT pixel circuit. There are some barriers needed to resolve to utilize hydrogenated amorphous silicon transistor to lit OLED, such as low field effect mobility, low output current and threshold voltage shift. In this article, a two-a-Si:H TFT pixel circuit was designed, which consisted of one named switching TFT and the other named driving TFT. The driving TFT gate line structure modified and a data signal timing improved were reported. The modified driving TFT can provide enough current about 30 microampere to lit OLED and the novel data signal timing can provide a constant current to OLED by restraining the driving TFT threshold voltage variation. In the novel data signal timing, the control signals to the driving TFT gate include a data signal and a reverse data signal. The signals alteration is performed either at a frame rate or at a line rate. By experiments, the driving TFT output current value is plotted as a function of the time in different reversed voltage value. When the magnitude of the positive data signal and the negative data signal is equal, the variety of ΔVth is smallest, about 1.28V after a fixed stressing time of 1.33×104min, which shows the novel data signal timing can improved the driving TFT output-input current stability.
Design and fabrication of color filters for projection display system
Xueke Xu, Jianda Shao, Zhengxiu Fan
Color filters is one of the most important optical components in the projection display system. The design and fabrication of high performance filters were described in this paper. A new admittance-matching method was approached, which the optimized matching layers only exsited at the interfaces: stack|stack, stack|substrate and stack|air, and the satisfied design results were achieved. This method is especially used for wide cut-off and wide bandpass filters. The analysis of the tolerance and angle senstivity were carried for the designed film stacks . Thermal stability was also tested for the prepared samples. The results of the experiment and analysis indicate that film stack got from the new interface optimizing method presented good optical and thermal stability.
Sulfuric acid treatment of indium tin oxide for application of organic light-emitting diodes
Wei-zhi Li, Xing-qiao Ji, Zhi-you Zhong, et al.
In this paper, indium tin oxide (ITO) substrates were treated by ethanol, sulfuric acid (98%) and oxygen plasma respectively, based on which organic light-emitting diodes (OLEDs) with the same double-layer structure: ITO/N,N'-bis-(1-naphyl)-N,N'-diphenyl-1,1'- biphenyl-4,4'-diamine(NPB)/tris-(8-hydroxyquinoline) aluminum(Alq3)/ Mg:Ag/Al were fabricated. The morphology and compositions of differently treated ITO films were analyzed by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). AFM results showed that all these treatments didn't change much the average roughness of ITO films, while ethanol has little influence on the large "peak-valley" (P-V) distance of ITO film; ITO film treated by sulfuric acid has suitable surface morphology with low P-V distance, low average roughness and small particle radius. XPS analysis proved that ethanol has the weakest ability to remove carbon contamination on the surface of ITO film which resulted in unevenly distributed current and high barriers for hole injection; sulfuric-acid-treated ITO film has the least contamination of carbon and higher concentration of oxygen vacancies, both of which are helpful for the improvement of devices. In the condition of room temperature and atmosphere and without encapsulation, measurements of the current-voltage, brightness-voltage and lifetime characteristics of these devices were conducted and showed good agreement with what expected from the results of AFM and XPS analysis: the ethanol-treated ITO provides very unstable performance with low efficiency for the device based on it, while the device based on sulfuric-acid-treated ITO anode had even better performance at higher driven voltage (>7V) comparing with the device based on oxygen-plasma-treated ITO substrate and had the highest current-luminance efficiency (3.2 cd/A) and the longest lifetime (2 hours).
Study on the electrical qualities of OLED with various thicknesses of the emissive layer
L. Chen, J. Q. Zhao, S. J. Xie
A numerical method was used to solve the bipolar injection problems for the multilayer organic light emitting diodes. The drifting motion of carriers under electric field and Langevin recombination in the emissive layer were considered, and the interface properties were quantified as ratio of injection to total current intensities. The electrical properties were analyzed with various thicknesses of the ETL, EML and HTL. The results show that the thickness of the EML plays an important role in the electric current and luminescent efficiency. To improve the luminescent efficiency, the thickness of the HTL or EML should be reduced. The reduction of the EML will significantly improve the performance of the multilayer OLEDs.
Effects on the spectrum of the blue organic light-emitting diodes by the indium tin oxide surface treatment
Xing-qiao Ji, Wei-zhi Li, Zhi-you Zhong, et al.
Deionized water, sulfur acid (98%) (H2SO4), sodium hydroxide (NaOH) solution and oxygen plasma are used to treat ITO substrates, then blue organic light emitting devices (OLEDs) with the structure of ITO/NPB(50 nm)/BAlq3(40 nm)/Alq3(25 nm)/Mg:Ag are fabricated in the vacuum. The experiment results show that ITO treatments influence the electroluminescence (EL) spectrum of the blue OLEDs, the OLEDs which are treated by four methods the EL spectrums change from 496 to 455 nm. According to atom force microscope (AFM) and X-ray photoelectron spectroscopy (XPS) analysis, the surface morphology and surface composition are greatly changed, so the surface work function is changed, then recombination zone of the carrier is moved, which leading to the emission spectrums alter. The ITO substrate is treated by oxygen plasma, which has the highest oxygen concentration, so the surface work function is the greatest, the hole can jump the barrier and recombine in BAlq3-Alq3 interface, the spectral peak is at 496 nm. The ITO treated by acid solution, the oxygen concentration is less than that of plasma treatment, so the surface work function is also less than it, thus the hole can inject into the BAlq3 layer, the spectral peak is at 480 nm. Roughness of deionized water treated ITO is the largest, which can became local high electric field, so some hole are excitated into the BAlq3-Alq3 interface, most of the hole are blocked by BAlq3 barrier, the light from BAlq3-Alq3 interface and NPB layer, the spectral peak is at 474 nm. The ITO treated by NaOH solution, the oxygen concentration is the lowest, so the surface work function is also the lowest, all of the hole are blocked by BAlq3 layer, they can only recombine in the NPB layer, the spectral peak is at 455 nm.
Low threshold field electron emission of diamond films
Lili Liu, Yuxue Xia, Song Chen, et al.
Since CVD diamond film possesses desirable properties, it has been widely investigated, and much research has been made in this field. In this experiment, we mainly studied the characteristics of field emission from the CVD diamond films. The motivation for the experiment is to gain some insight into a possible emission mechanism. The diamond films are grown using a hot filament chemical vapor deposition, basing on the diamond micro-grits on silicon substrates. And the diamond micro-grits are deposited on silicon substrates using electrophoresis coat method, through a solution of diamond micro-grits in ethyl alcohol. This study has revealed that emission can be obtained at fields as low as 1.8V/μm. And the field emission measurements were carried out at a pressure of 10-4Pa.
Field emission properties of ZnO nanowires
X. Q. Meng, D. Z. Shen, J. Y. Zhang, et al.
ZnO nanowires were obtained by using a simple vapor solid process. The length of the nanowires is about 1 μm, with diameters ranging from 40 nm to 150 nm. X-ray diffraction (XRD) pattern confirms the nanowires are wurtzite structure with c-axis preferred orientation. Photoluminescence (PL) measurement shows a strong UV emission and a weak visible emission. Field emission (FE) results proved the nanowires have low turn-on voltage and high field enhancement factor, which indicates ZnO nanowire is a suitable candidate for field emission display.
Influence of ITO surface treatments on the performance of polymer light-emitting diodes
Zhi You Zhong, Ya Dong Jiang, Tao Wang, et al.
Solvent cleaning and oxygen plasma treatment were carried out on the indium-tin oxide (ITO) anodes for polymer light-emitting diodes (PLEDs). The influences of different treatment methods on the surface properties of ITO anodes were investigated using different standard surface characterization techniques, i.e., X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and contact angle. Based on the measurements of contact angles, the surface energies of the ITO anodes were also calculated using the harmonic-mean method. We observe that the surface treatments decrease the carbon content, increase the oxygen content, reduce the surface roughness and enhance the wettability, and thereby improve the surface properties of ITO anodes. With respect to the solvent cleaning, the oxygen plasma treatment is more efficient since it brings about a better improvement in the ITO surface properties due to the contaminants can be removed effectively from the ITO surface. Furthermore, we studied the effect of surface treatments of the ITO anodes on the characteristics of PLEDs, in terms of the electrical and optical performance of the devices. Experimental results reveal that the surface treatments improve the electroluminescent characteristics of the PLEDs. The oxygen plasma treated device gives smaller turn-on voltage and driving voltage, higher brightness and efficiency as well as better quality of light emission compared to the solvent cleaned device. The result can be attributed to oxygen plasma treatment improves the surface properties of ITO anode and the interface characteristics of ITO/polymer.
Ageing effect of treated ITO substrates on the performance of organic electroluminescent devices
Ya Dong Jiang, Zhi You Zhong, Tao Wang, et al.
Indium tin oxide (ITO) substrates were treated by oxygen plasma for organic light-emitting devices (OLEDs). Using the ITO substrates aged for various times as hole-injecting electrodes, the double-layered OLEDs were fabricated by vacuum evaporation process, and the ageing effect of treated ITO anodes on the performance of OLEDs was studied with respect to the electroluminescence lifetime, efficiency, luminance and driving voltage. Experimental results reveal that the luminescent and electrical characteristics of the OLEDs are strongly dependent on the properties of the ITO anodes used, and the ITO anodes aged for various times result in significant differences in device performance which become worse with the increment of the ageing time. The measurements of X-ray photoelectron spectroscopy (XPS) and contact angle show that the carbon concentration increases, the oxygen concentration decreases and water contact angle raises, and thereby the improved surface properties of ITO tend to decay, as the ageing time increases. It indicates that the change in the electroluminescent performance of the OLEDs is closely related to the changes in the chemical compositions and wettability of the ITO anodes.
A new driving method for LCoS with frame buffer pixels
Yulong Song, Zhihua Ling
A new driving method for LCoS microdisplays with frame buffer pixels was developed here. The power dissipation of the LCoS microdisplays with frame buffer pixels is higher than that of the LCoS with DRAM-like pixels due to the twice samplings in LCoS with frame buffer pixels. In this paper, an adiabatic charging method was used to the second sampling of the frame buffer pixels in order to reduce the power dissipated in the transistors. The power dissipation of the second sampling was calculated when the power sources of the step, the ramp and the stair-step are used respectively. The conventional design adopted the step and contributed to high power and so result in more heat to deteriorate the device performance. The power dissipated in the transistors is almost zero if the ideal ramp source is used. The ramp can be the stair-step whose steps are infinity. The stair-step substitutes for the ramp due to easily generation and higher energy efficiency than the step. It can decrease the power dissipation of the LCoS panel and contributes to the heat reduction caused by power dissipation which can increase the microdisplay devices reliability. This method was developed based on the frame buffer pixel circuits which we proposed previously and can be applied to the others.
Fluorescence lifetime and quantum efficiency of Y2O3:Eu nanocrystals
Qingyu Meng, Baojiu Chen, Wu Xu, et al.
Bulk Y2O3: Eu (1% in molar ratio) powders and nanocrystals with different particle size were prepared by chemical self-combustion, all of them exhibits cubic structure. Fluorescent decay curves at room temperature and 10k, excitation and emission spectra were measured. The dependence of fluorescence lifetime on the particle size and temperature were discussed. Meanwhile, the quantum efficiency of 5D0 level of europium ion occupying C2 site was estimated.
The effect of electrode materials on the performance of OLEDs
Z. Y. Zhong, Y. D. Jiang
The organic light emitting devices (OLEDs) with the Al, Mg-Ag and LiF/Al cathodes were fabricated by the vacuum sublimation technique, and the effect of the cathode materials on the electroluminescence (EL) characteristics of OLEDs were investigated in terms of the optical and electrical properties. The experimental data and calculation results demonstrate that the electrical and luminescent performance of OLEDs is strongly dependent on the property of cathode material and the characteristics of the cathode/organic interface. The EL characteristics of device with the LiF/Al cathode is better than those of devices with the Mg-Ag and Al cathodes. The device with LiF/Al cathode exhibits highest EL luminance and efficiency, and smallest turn-on voltage and driving voltage. Such an improvement in the device performance can be attributed to the more efficient electron injection at cathode/organic interface, and the better balanced hole and electron recombination in the light-emitting layer, and the fewer accumulated charges near the organic/organic interface.
In-plane-switching π-twist liquid crystal displays
Yubao Sun, Hongmei Ma, Zhidong Zhang
An in-plane switching π-twisted liquid crystal device with fast response speed is proposed. Electric filed is applied in the plane of the substrates, unlike a conventional π-cell. Two quarter wavelength films are used to obtain black/white mode. The electro-optical characteristics and switching behavior of this mode are studied by using two-dimensional model. A good dark state is obtained when the electrode is black. Numerical results show that the proposed mode has excellent viewing angle and fast response speed.
Backflow effect in an inverse twisted nematic liquid crystal display
Zhidong Zhang, Li Jiang
Based upon the Ericksen-Leslie hydrodynamic equations, we studied an inverse twisted nematic liquid crystal cell, in which the liquid crystal is untwisted in the field-off state and twisted in the field-on state. The time evolution of director configuration and velocity of flow was obtained by computer simulation. An abnormal director profile that caused by the backflow appeared after switching on the holding voltage. We also compared the optical transmittance of the inverse twisted nematic liquid crystal cell having backflow effect with that without considering backflow effect.
Temperature dependence of structural and luminescent properties of Tb3+ doped YPO4
Weihua Di, Xiaojun Wang, Baojiu Chen, et al.
The solution precipitation is used to synthesize the Tb doped yttrium phosphates. The as-synthesized is the monoclinic phased YPO4×2H2O with churchite-type structure, which is transformed to the tetragonal phased YPO4 with xenotime-type structure as the temperature approaches 200°C during the thermal treatment process. This phase transformation process can not be observed in some routes that need a higher synthetic temperature, in which, only a high-temperature phase is obtained. The luminescent efficiency dependence on the heat-treatment temperature is investigated. The luminescent efficiency presents a two-step increase respectively around 300 and 700°C. Results indicate that the significant increase of luminescent efficiency at 300°C is not related to the phase structure transformation, but to the decrease of OH- ions content, and that the significant increase of luminescent efficiency at 700°C is related to the increase of crystallinity, which may increase the absorption to VUV light.
Luminescent properties of YBO3: RE3+(RE=Ce,Tb) in the UV/VUV region
Xiaoxia Zhao, Xiaojun Wang, Baojiu Chen, et al.
Ce-, Tb-doped and co-doped YBO3 were prepared by solid-state reaction. The structure of the powder is identified as vaterite-type structure. The photoluminescence of the samples under UV/ VUV excitation were investigated. The results indicate that the energy is transferred between Ce3+ and Tb3+ under UV excitation while Ce3+ is not beneficial to the emission of Tb3+ under VUV excitation due to the different luminescence mechanism. The blue emission of Tb3+ was observed at low Tb3+ concentration and disappeared at high activator concentration due to the relaxation.
Digital photofinishing system based on liquid crystal on silicon
Minmin Zheng, Huimin Yan, Xiuda Zhang, et al.
As the digital camera user base grows, so does the demand for digital imaging services. A new digital photo finishing system based on Liquid Crystal On Silicon (LCOS) is presented. The LCOS panel motherboard is made up of CMOS chip. Three individual streams of light (red, green, blue) are directed to corresponding Polarization Beam Spliter (PBS) to make the S polarization beam arrive at LCOS panel. When the Liquid appears light, the S polarization beam is changed to P polarization beam and reflected to pass through Polarization Beam Spliter. Compared with Thin Film Transistor-Liquid Crystal Display (TFT-LCD), LCOS has many merits including high resolution, high contrast, wide viewing angle, low cost and so on. In this work, we focus on the way in which the images will be displayed on LCOS. A liquid crystal on silicon microdisplay driver circuit for digital photo finishing system has been designed and fabricated using BRILLIAN microdisplay driver lite(MDD-LITE) ASIC and LCOS SXGA (1280×1024 pixel) with a 0.78"(20mm) diagonal active matrix reflective mode LCD. The driver includes a control circuit, which presents serial data, serial clock , write protect signals and control signals for LED, and a mixed circuit which implements RGB signal to input the LCOS. According to a minimum error sum of squares algorithm, we find a minimum offset and then shift RGB optical intensity vs voltage curves right and left to make these three curves almost coincide with each other. The design had great application in the digital photo finishing.
Fabrication of polysilicon thin film on glass with low-temperature UV-assisted crystallization
J. Y. Huang, Zh. H. Ling, H. Jing, et al.
The amorphous silicon (a-Si) film was crystallized on glass by a simple method employed ultraviolet at temperatures as low as 400°C. The employ of ultraviolet enhanced the crystallization of amorphous silicon. This method is able to uniformly crystallized large-area amorphous silicon films. The polysilicon films crystallized by this way are suitable for the fabrication of thin film transistors on ordinary glass. Crystallization process is performed in a furnace. Amorphous silicon sample is placed on a hot plate and irradiated by a bank of ultraviolet lamps through a diffuser plate to improve the uniformity of light that irradiates the sample. Raman microscopy is used for analyzing the qualities of UV-assisted crystallized silicon films. By measuring the Raman spectra the effects of anneal temperature and process time on the crystallizing behavior, crystallinity and grain size of the processed films were obtained. There has a threshold temperature for crystallization of amorphous silicon film in the presence of ultraviolet irradiation with certain intensity, i.e. by ultraviolet irradiation with certain intensity only when the temperature is up to the threshold temperature, the crystallization can be triggered. The threshold temperature is 400°C when the intensity of ultraviolet irradiation is 1mW/cm2. Above threshold temperature, the increase of anneal temperature increased the rate of crystallization. Crystallinity and grain size extracted from Raman spectra of samples increase with the extending of process time at certain temperature. Crystallization of amorphous silicon film with thickness of 50nm completed within 6 hours at 400°C irradiated by ultraviolet with intensity of 2mW/cm2.
Novel green and red PLEDs based on silole-containing polyfuorenes
The photoluminescence (PL) and electroluminescence (EL) properties of two series of novel silole-containing polyfuorenes were comparatively investigated. The band gaps of the copolymers could be tuned by structural designing of siloles and control of molar ratios of the siloles in the copolymers. The copolymers showed strong intra- and inter-molecular energy transfer in the solid state, from which the blue emission from polyfluorene could be suppressed and green and red EL devices based on the two series of copolymers could be achieved. Photovoltaic cell and field effect transistor properties of some copolymers were also evaluated.
The project realization of eliminating stereo display flicker
The paper introduces a method that uses the video signal digitized processing module to display the stereo image. In the paper, it introduces a realization project using time-division stereo analog display, discusses a realization method of stereo display which uses video signal of twin-channel video synchronous camera and the digital scanning processing chip that bases on the programming under the bus, analyzes the cause of producing the image flicker during the common stereo image display, adopts the advanced PHILIPS MK-9 module to carry out the data acquisition and memory to the video signal, resolves the problem of image flicker by using "multi-field scanning" and "sequential scanning", it can make the observers acquire more comfortable stereo feeling.
Direct design of a polarization interference filter by adaptive simulated annealing algorithm
Yuling Liu, Yanping Chen, Jingyi Xiong, et al.
Polarization interference filters (PIFs) could substitute for thin films in three-panel projection systems for color separation/combination. Conventional methods of designing PIFs use inverse propagation of optical networks making the design procedure very complicated. The design of PIFs requires the determination of the thickness and orientation of the birefringent crystals. On the basis of analyzing several traditional algorithms, we advance a method of exploring all the possible thickness of the crystals, and the self-initiated weighted least squares (SWLS) method combined with adaptive simulated annealing (ASA) is proposed to find out the orientation of the crystal. This Chebyshev criterion based on optimal approximation method has not only fast speed but also high accuracy and good controllability. Finally, experimental results both for the spectral and angular properties are given thoroughly. The experimental and designed results are well matched. In particular, the good angular property of PIF is validated.
Dependence of the molecular reorientation on the direction of incident light in azo-dye doped liquid crystals
Luogen Deng, Guohui Wang, Junliang Zhang, et al.
This paper investigates an optical reorientation process of azo-dye doped liquid crystals and explains the dependence of the enhancement factor on the incident light direction. Because the order parameters of the guest-host liquid crystal system depend on the direction of the incident light, the intermolecular orientation interaction potentials is also related with the incident light direction. To describe the interaction between the cis-isomer and the liquid crystalline molecules, we re-wrote Maier-Saupe potential expression by means of the order parameters of the doped liquid crystal system. Beginning with a two-level coupling equation, we investigated a microscopic formula and an angular dependence of the enhancement factor with the liquid crystal E63 doped with the R4 azo-dye, and obtained the relation of the enhancement factor with the rotational diffusion constants and the host order parameter. The comparison of our computational results with the existent experimental results verified our enhancement factor's microscopic form.
Study on the fabrication of orange micro-LED arrays for display
Xia Jin, Jingqiu Liang, Jia Li, et al.
Arrays of micro-sized LEDs which can be used as microdisplays have been demonstrated in recent years. In order to reduce the input and output connections to the arrays, we employ a matrix addressable architecture, in which all the pixels in each row are connected by a common metal line on the top of the window layer (top electrode) or at the base of substrate(bottom electrode). Decreasing the size of electrodes makes for minimizing the size of device. The optic and electronic isolation and good ohmic contact are also helpful to obtain superior optical and electrical performance. We describe a procedure of fabrication of AlGaInP-based orange micro-LED by wet etching. The structure of devices is etched using both isotropic and anisotropic solvent. The pixel size is about 16um x 20um, and there are 1000 x 818 pixels in the light emitting chip whose diagonal is 1-in.
Development of high definition liquid crystal display with excellent moving image
Hidehiro Seki, Kazuhiro Wako, Kazuo Sekiya, et al.
It is easy for the liquid crystal to save the electric power for non-emissive display essentially in various flat panel displays, and to improve the electro-optical property by function separation of a light source and an optical control, etc. However, the utilizing efficiency of light in liquid crystal displays is about several %. One of the low efficiency factors is a color filter. We adopted the FS method to switch the light source color using OCB mode with excellent switching speed. This method is a technology that displays full colors by switching a red, green, blue image at high speed sequentially. The merit of this method is high efficiency without using the color filter that absorbs 67.1% of the backlight, and it is a useful skill to the power consumption reduction of the liquid crystal panel. In addition, there is an advantage that clear motion image can be displayed for this method to blink the source of the backlight at high speed. The 6-inch LCD panel with the FS OCB mode was manufactured. The clear motion image, high utilizing efficiency of light, and large color gamut were achieved.
A power system design and analysis of carbon nano-tubes field emission displays
Jong C. Wang, W. C. Yao
In new generation Flat Panel Displays(FPD), a lot of design methods are being deployed, including OLED, PDP, TFT-LCD, Back Projection and Field Emission Display(FED) etc. These new generation FPDs have their respective pluses and minuses. Each has its selling points and market attractions. But among them, FED principles are most close to that of CRT displays. Not only FEDs are advantageous in their good degree of saturation of color, but also they have excellent contrast, luminance and electricity consumption etc. It has been considered as the main products of future generation FPDs. Japan and countries all over the world are successively proposing and launching related FED products in the fields. This will not only drive the FEDs into a wave of new trends, but also it will be able to replace most of the current FPD products within a short time. In this paper, based on these solid trends, we are determined to put into our resources and efforts to perform research on these important FEDs technologies and products, particularly in Carbon Nano-Tubes FEDs(CNT-FED). Our research group has already performed research on CNT-FED subjects for almost three years. During the course of our research, we have run into a lot of issues and problems. We have made every effort to overcome some of them. This paper performs comparative analysis of three power option for small size (4-inch) CNT-FEDs to drive the FED effects such as the direct current power, pulsed power and sinusoidal power respectively. This paper performs comparative analysis of three power options for small sized CNT-FEDs. It was concluded that the pulsed power option will produce the best results overall among the three power options. It is felt that these data presented can then be referenced and used to design a power system circuit to get an optimum design for better luminance and least power consumption for small sized commercial CNT-FED products.