Liquid crystal display (LCD) is a highly capital-intensive business venture, where billions of dollars have been invested worldwide yet the prospects are both financially and technically volatile. Unlike global qiant entrepreneurs, domestic industries related to flat panel display are of relatively small size. A distinct strategy to stay competitive is therefore required. This report summarizes the efforts made in developing LCD backlighting components in Taiwan, Republic of China. Because they are indispensable in LCD applications, companies have successfully learned their way to stay out of risk when keeping up with state-of-the-art technologies.
We have improved the viewing angle characteristics of TFT-LCDs by domain-divided twisted nematic (DDTN) panels in normally black mode with retardation films. The viewing angle of ±80° (contrast ratio > 5) was realized for both vertical and horizontal directions. Also we have developed a polymer-dispersed LCD with crossed Nicols (PDN) with a unixial retardation film. The TFT-LCD fabricated produced high contrast display without brightness level inversion among gray scales for any viewing directions.
We have made a test panel of active matrix liquid crystal display (AM-LCD). To know the optimum values of design parameters is important to design AMLCD panel with optimum electro-optic characteristics. We made test panel with various gate line width, W/L, storage capacitance, etc. We could obtain much informations from a test panel. We studied the brightness and flicker for various design of pixel.
The amplitude and the propagation delay time of oscillation waveform of the ring oscillator made of n-channel amorphous-silicon thin film transistors decrease as the geometry ratio β decreases. The propagation delay time can also be decreased by reducing the gate source/drain overlap and the channel length of the transistors. Measurements on a ring oscillator at V_<GG>=V_<DD>=15V show a propagation delay time of 0.5 μs per gate and a power-delay-time product of 15 pJ per gate. The channel length of the load and driver transistors is 3 μm with a gate source/drain overlap of 2 μm. With this experimental result, using amorphous-silicon thin-film transistors to manufacture the peripheral driver circuits on the panels of 640 x 480 active-matrix liquid crystal displays can be achieved.
Using thin film optical interference filters for color filters applications in Liquid-Crystal displays was proposed in this present study. Structures were adopted such as (TiO_2/SiO_2) to form optical bandpass filter as well as edge filter to design the color filters. The optical performance of transmittance, FWHM, viewing angle, and chromaticity of red, green and blue filters were analyzed. The spectrums of R, G, B color filters were found to have a, high transmittance (>85%). A comparison of optical interference filter and dye-gelatin filter with NTSC standard in CIE (u, v) chart revealed that the former has a higher purity, and better reproducibility than the latter. Their optical characteristics were observed as being relatively uniform over the viewing angle ranging from -15° to 15° which could possibly be adequate for projection LC-TV applications.
An improved, high resolution, low voltage Einzel electron gun was designed with simplified grid structure which allows mandrel beading in production and provides proper shielding from the stray electrostatic field as well. This new gun provides 15% better spot size than the conventional design.
Impreganted tungsten cathodes half-coated wth Re/W (or Os/W) alloy and Os/Re/W alloy at right angles were studied to compare the dffects of Os/Re/W alloy coatiings on the electron emissionand emissiion mechanisms. Constant surface metal compositions of 32% Os-29% Re-39% W and 35% Os-26% Re-39% W were obtained from the activated surfaces initially coated with 40% Os-40% Re-20% Wand 35% Os-45% Re-20% W alloys, respectively. Thermionic emission microscopy measurements showed that the Os/Re/W alloy-coated surface gives an average effective work function of 0.29, 0.08, and 0.03 eV lower than the uncoated, Re/W and Os/W alloy-coated surfaces. An effective work function of 17.3 eV was obtaiined from and activated Os/Re/W alloy surface. Auger studies exhibiteda smaller BaO coverage and a higher barium coverage in excess of BaO stoichiometry on the Os/Re/W alloy-coated surface compared to the uncoated, Re/W alloy and Os/W alloy-coated surfaces.
When the mask is bombarded with a high energy electron beam, it will heat-up the mask and cause thermal expansion. This thermal expansion (doming effect) will occur spot displacement and deteriorate the color purity of CRT. The infrared emissivity and the electron-backscattering coefficient of the mask are two influential factors on doming behavior. The influence of mask with Bi203 and Barium coatings on the emissivity and backscattering coefficient are studied. The doming behavior is modeled directly as a function of Bi203 and Barium coatings on mask and indirectly as a function of the emissivity and the backscattering coefficient.
With incresing demands on antistatic properties of CRTs, which will eliminate electrical shocks due to static charge built up especially under low humidity environment, tremendous efforts were made to investigate means of fast discharging. While most of the studies were concentrated on conductive metal ion type (such as Li) or semiconductor type (such as ITO) coatings, very few studies have been conducted to investigate the true mechanisms of hy groscopic type antistatic effect. Published literatures suggested that, under hygroscopic mode, antistatic properties come from the adsorption of moisture from air at the surface of coating due to the presence of hygroscopic ions. Based on this hypothesis, antistatic properties will disappear if this type of hygroscopic ion is absent. However, in this paper, some controversies were observed in our results, and discussion will be made based on these
The dependences of crystallinity on growth conditions of the ZnS thin films deposited on the ITO/glass substrate by low-pressure MOCVD system have been studied. The high-quality ZnS thin films with strongly preferred orientation can be grown under the optimum condition : the substrate temperature, the reactor pressure and [H_2S]/[DMZn] molar ratio are 225 ℃, 30 Torr and 20, respectively. The Δ2θ value can be reduced below 0.175°. The atomic ratio of S/Zn and the lattice constant obtained are 0.96 and 5.418 A, respectively. Furthermore, the large-area, 130*190 mm^2 ZnS thin films are grown by optimum conditions. The uniformities in film thickness and crystallinity have been measured. Although less than 10% variation in the thickness and FWHM values have been got, the variation must be further improved in the future.
A new self-aligned process was developed for fabrication of vertical field emission triodes with gate opening less than 0.5 μm diameter. A large area array of such closely-spaced gated emitters would serve as a distributed electron source for a field emission flat panel display. The characterization of the gated silicon emitter showed that the electron emission followed Fowler-Nordheim behavior. Single emitter had turn-on gate-cathode voltage above 25 volts (typically 50 - 90 volts) and reproducible emission currents were measured in the range 5 pA - 1 μA.
The Mn^<2+> luminescent center m ZnS:Mn powder and thin films has been studied by electron paramagnetic resonance (EPR) as a function of fabrication processing condition. The results of EPR showed that the effective Mn^<2> concentration in ZnS:Mn phosphor layer may be changed by the annealing process after deposition as well as substrate temperature during deposition. Vacuum annealing and oxygen plasma exposure for ZnS:Mn phosphor layer resulted in high brightness with better luminous efficiency and showed good aging characteristics. However, in case of ZnS:Mn powder, no spectral change was observed after O_2 treatment.
The complete structure of gated silicon field emitter arrays (GSFEA) based on the silicon micromachining technology has been demonstrated. The uniform and extremely sharp Si tip arrays were formed using wet chemical etching and low-temperature oxidation sharpening (LTOS). A mesh structure has been used to calculate the electron-beam behavior in the vicinity of the microemitter apex. The focus effect of field emission was proven to be very effective. Four types of microtips have been simulated to understand the effects of the field-enhancement factors and the effective emission area.
Controlling the display quality of a monitor concerns adjusting the circuitry to maintain an optimal operation condition of the monitor. This paper describes the development of an automated alignment system for monitor production line. Such a development not only reduces the amount of labor work spent in the production process, but also yields highly reliable quality of the products. The concept of overall system design with the discussion of technical contents is the main focus throughout this paper. Measurement results are analyzed to illustrate the capability of this system. This paper also discusses the issue of integrating the developed system into the computerized plant-wide environment.
An improved simulation program of moire pattern on computer has been developed to have quantitative judgements based on numerical simulation. This simulation is used when decisions have to be made for particular shadow mask choices and judgement has to be made about applicability of more optimized design shadow mask of color CRT displays.
The optical efficiency and colorization on the optical configuration of Liquid-Crystal (LC) projection TV were studied. The functioning of R, G, and B color filters of a LC projection TV is defined by the transmittance and reflectance spectra of dichroic mirrors (DMs). The S- or P-polarized spectra of transmittance and reflectance of dichroic mirrors become different from each other when the light is obliquely incident. The choice of LC panels, normally black (NB) or white (NW), along with its orientation with respect to dichroic mirrors would influence the color exhibition and optical efficiency of the LC projection system. For the same optical components, S-polarized was found to have both a higher optical efficiency (39.89% vs. 25.12%), as well as a better color reproduction than P-polarized light. The S-polarized transmittance of dichroic mirrors is higher and the spectra are smoother than those of P-polarized transmittance spectra. The NB type LC panel, where a polarizer is positioned parallel to S-polarization, was observed to perform more effectively from an optical perspective than a NW LC panel in a LC projection TV.