A novel hermetic‐sealing material for FEDs

Abstract— An hermetic‐sealing material for FEDs composed of thermosetting polyimide and glass fiber, has been developed. The main backbone and end‐capping material of polyimide were investigated to satisfy both high Tg and high flowability. A thermosetting function, 4‐phenylethynylphthalic anhydride (PEPA), was used as the end‐capping material. The fracture of a rigid and softening structure was optimized in the main polymer structure. The obtained polyimide demonstrated both a high Tg (265°C) and low viscosity (98 Pa‐sec at a sealing temperature of 350°C). In order to improve the gas permeability and the mechanical and thermal characteristics of the sealing material, a mixture of various types of ceramic fillers and polyimide has been investigated, and glass fiber was adopted. When 30 wt.% of glass fiber was combined when the developed polyimide, the Ar permeability and coefficient of thermal expansion of the sealing material decreased to below one‐half of the base polyimide. This material enables us to seal at a temperature of about 350°C in nitrogen atmosphere and shows superior performance suitable for glass‐to‐glass sealing.     

Large‐area FEDs with carbon‐nanotube field emitter

Abstract— Application of carbon nanotubes (CNTs) as field emitters for large‐area FED panels is described. In 1998, we presented the first experimental devices: light‐source tubes for outdoor large‐area displays and a diode‐type flat‐panel display, both with screen‐printed CNT cathodes. The fisrt practical high‐luminance color CNT‐FED panel was built in 1999. It employed the new triode‐structure panel was x‐y addressable. The CNT‐FED structure was further optimized for large‐area display panels by improving the luminous uniformity. This paper also describes the design and performance of a new, experimental, 40‐in.‐diagonal panel, which showed that the CNT‐FED technology is suitable for use in large‐area displays.     

The influence of ambient gases during the frit-sealing cycle on the emission characteristics of Mo-FEAs

Abstract— A 3.5-in. full-color field-emission display (FED) has been developed. The Spindt-tip array with a pixelated anode produces uniform and clean image. Changes in electron emission characteristics before and after the frit-sealing cycle were measured on the same field-emitter arrays (FEAs). Properties of thin Mo films after frit sealing in various gaseous ambients were estimated by AFM, AES, SIMS, and XPS. The possibility of applying Ar as an ambient gas during the frit-sealing cycle for vacuum packaging of field emission displays (FEDs) was reported. A set of uniquely printed spacers with high aspect ratios was fabricated on ITO-coated glass for high-vacuum packaging. The low-voltage phosphor was tested at an anode voltage of 300 V. Finally, full-color images of 64 gray scales will be demonstrated.     

High‐efficiency light‐collection optics for lamp‐based projection TV

Abstract— A new light‐collection optics has been developed that enhances the luminance of projection TV which use lamps as the light source. The conventional optical system consists of an elliptical reflector and a flat‐surface front glass, but these systems cannot sufficiently collect the beams coming from the light source, and they cause loss in the coupling with the light pipe. To solve this problem, we devised a new optical system through a structure of an aspherical reflector and an aspherical front glass. This new optical system concentrates the beams coming from the light source to a smaller point which improves the coupling efficiency. Thus, we have successfully increased the luminance of the projection TV by approximately 10%. This paper reports the design principles of the new optical system and the results of a prototype experiment.     

Practical CNT‐FED structure for high‐luminance character displays

Abstract— A high‐luminance CNT‐FED character display using a simple line rib structure was constructed. The display panel had 48 × 480 dots and the subpixel pitch was 1 mm. The greatest benefit of a display using CNT technology is high luminance performance with low‐power consumption. The luminance of the green‐color dot wasca. 10,000 cd/m² under 1/1 6 duty‐cycle driving at a 6‐kV anode voltage. The high luminance of the display panel can provide good visibility when installed even in outdoor locations, and the power consumption was ca. 4 W at the character displaying module. This, a CNT‐FED for character displays also has potential multifunctionality, which could be battery driven. It should be useful for public displays even under emergency no‐power conditions. In this work, a practical structure and process technologies for making ribs with reasonable cost were developed. The newly introduced 2‐mm‐tall line ribs as spacers were formed by using innovative production processes; i.e., the rib paste was pushed out of a multi‐slit nozzle, and the rib shape was formed by UV‐light irradiation. The developed panel structure and manufacturing processes also had the advantages of size flexibility and high production yield.     

Super‐large‐sized TFT‐LCD (55 in.) for HDTV application

Abstract— We have developed the world's largest TFT‐LCD, which has a 55‐in.‐diagonal size. This LCD features a 1920 × 1080 (16:9) resolution for full‐HDTV images, 500‐nit luminance, 72% color gamut, and 12‐msec response time at all gray levels. The size of the panel (55 in.) was determined by the maximum efficiency of our fifth‐generation line (glass size: 1100 × 1250 mm). To overcome the limitation of size in photolithography equipment, a new stitcking‐free technology was applied in both the TFT and color‐filter side. And the super‐IPS mode was used as a wide‐viewing‐angle technology because it is suitable in the fabrication of large panels. In this paper, we present issues on both the fabrication and characteristics of the 55‐in. TFT‐LCD.     

A new vertical‐alignment LC mode with high‐transmittance and fast‐response‐time features

Abstract— A novel pixel design for vertical‐alignment LCDs with superior transmittance has been developed. The new liquid‐crystal mode, refered to as the hole‐induced vertical‐alignment mode (Hi‐VA), uses a via hole of an organic layer on a TFT substrate to achieve multi‐domain alignment. Compared to the conventional design, the Hi‐VA mode has a transmittance of up to 135% with a contrast ratio of 2000:1. Moreover, the new structure is free from ITO patterning or protrusion on the color‐filter side, which makes the fabrication process simple and low cost.     

A novel low‐power‐consumption all‐digital system‐on‐glass display with serial interface

Abstract— A new conceptual ultra‐compact LCD panel, which features a simple interface and lower‐power consumption by using low‐temperature polysilicon thin‐film transistor (LTPS‐TFT) technology has been developed. This panel is capable of switching operation modes based on an input command, and all the data are directly communicated with the circuit inside the panel through a Serial Peripheral Interface (SPI) protocol. The integration of the serial‐data‐receiver function on glass substrate has enabled the achievement of a significant reduction in the number of interface pins. Moreover, a low power consumption of 15 μW for a 2.26‐in. reflective LCD panel in combination with the technique of integrating a memory circuit in each pixel has been achieved.     

A new optical elasticity resin for mobile LCD modules

Abstract— The display used in current cell phones has an air gap between the cover glass and the liquid‐crystal‐display (LCD) module to prevent the LCD glass from being damaged. Reflections at the boundaries of the air gap cause a reduction in the LCD luminance and contrast. To address this problem, a newly proposed LCD structure has been investigated. The “Super View Resin (SVR),” a transparent elastic resin which improves the shock resistance and visibility of the LCD, has been developed. Filling the air gap between the cover glass and LCD module with a refractive‐index‐matching resin solves the light‐reflection problem inherent in the use of a reinforced cover‐glass lens. Moreover, the elastic filler works as a damper, reducing any external shock, which prevents not only the cover glass and LCD module from being damaged, but also the glass from being shattered when it is broken.     

High‐luminance 1.8‐mm‐pixel‐pitch CNT‐FED for ubiquitous color character displays

Abstract— A high‐luminance 1.8‐mm‐pixel‐pitch CNT‐FED for color character displays has been developed. The display panel has 32 × 256 color pixels, and the subpixel size is 0.6 × 1.8 mm. The display panel can provide good visibility when installed even in outdoor locations. The power consumption is low enough for the display to be battery driven. The practical application is the display of important messages regarding the evacuation from disaster areas, even under emergent no‐power conditions similar to the messages on vending machines.     

Glass substrate for micro display devices

Glass substrate suitable for wearable micro display devices for augmented/virtual reality was developed. This glass has highly matched thermal expansion coefficient with that of silicon, and it enables to suppress the amount of warpage caused by the boding between Si and glass wafers. The glass also shows lower thermal shrinkage than that of conventional non‐alkali glass for thin‐film transistor substrate. In this paper, the effect of the temperature dependence of the thermal expansion coefficient on warpage generation after bonding process was investigated using both numerical simulation and experiment. The newly developed glass showed remarkably low warpage after the bonding process.     

Polyimide‐free LCD by dissolving dendrimers

Vertical alignment (VA) and in‐plane switching modes have been widely used for liquid crystal displays (LCDs). They require a polyimide (PI) alignment layer in the pixel structure. PI‐free LCDs have been proposed to exploit the VA of liquid crystals (LCs) obtained by dissolving dendrimers without PI. In this paper, we report a new PI‐free VA mode with a pixel structure that has in‐plane electrodes. The PI‐free VA is achieved by dissolving an LC dendrimer in a positive LC mixture. We measured the test cell properties and obtained a lower voltage and a higher brightness in the voltage–brightness curve. In addition, we analyzed the alignment surface of LC dendrimer by time‐of‐flight secondary ion mass spectrometry and scanning electron microscopy observations. We found that dendrimer molecules are uniformly adsorbed on the glass surface and that the layer was generally one molecule thick. These properties are responsible for the lower voltage and higher brightness of the PI‐free VA mode. The use of dendrimers allows the PI process to be omitted and reduces the power consumption of the VA mode. It is thus possible to reduce the high manufacturing costs and improve the performance of the VA mode.     

LTPS circuit integration for system‐on‐glass LCDs

Abstract— A 3.5‐in. QVGA‐formatted driving‐circuit fully integrated LCD has been developed using low‐temperature poly‐Si (LTPS) technology. This display module, in which no external ICs are required, integrates all the driving circuits for a six‐bit RGB digital interface with an LTPS device called a “FASt LDD TFT” and achieves a high‐quality image, narrow frame width, and low power consumption. The LTPS process, device, and circuit technologies developed for system‐on‐glass LCD discussed. The development phase of LTPS circuit integration for system‐on‐glass LCDs is also reviewed.     

Status of glass‐bulb development for flat and thin CRTs

Abstract— The next goal to minimize the bulkiness of CRTs is most likely to attain half the depth of conventional CRTs, while keeping the weight within a reasonable range. Several innovations for reducing the bulkiness of glass bulbs for wide‐deflection‐angle CRTs have been made and further technologies are being developed by improving material and structural approaches. The integrated glass technology based on these innovations will provide a lightweight shallow glass bulb and the impetus to achieve this goal.     

Numerical study of the electron and ion trajectories in HOPFEDs

Abstract— A hopping‐electron field‐emission display (HOPFED) is a field‐emission display (FED) with a new and revolutionary spacer structure. In a HOPFED, two insulator plates, referred to as hop and flu spacers, are sandwiched between the emitter and front plate. The objective of this spacer structure is to improve the performance of a FED substantially, notably contrast, color purity, and luminance uniformity. Another advantage is the reduced sensitivity of ion bombardment on the field emitters. We show by numerical methods that both the luminance uniformity and the sensitivity of ion bombardment improve substantially in a HOPFED.     

A 25‐in. SMPDP with fine pitch and high resolution

Abstract— A 25‐in. SMPDP with fine pitch and high resolution has recently been developed as a succession of the 34‐in. SMPDP, which had been exhibited at ASID '04. SMPDP was regarded as a hopeful low‐cost PDP solution. The new pitch size of 0.66 mm realized an SVGA resolution on this 25‐in. SMPDP, and it also promises HDTV‐resolution compatibility for a 42‐in. SMPDP. The discharge cell has been re‐designed and the delta‐type arrangement of discharge cells has been applied, which provides more display area and facilitates the panel fabrication as well. Other modifications, such as the bus‐electrode structure and the alternatives of the glass material for substrates, have been tested. A peak luminance of 500 cd/m² and a total power consumption of 100 W has been achieved for the 25‐in. SMPDP sample.     

A study of 3D cover glass design that improves handheld device drop reliability

Cover glass in commercial handheld devices is now evolving from flat (2D) to curved (3D) shapes. For example, some commercial devices have utilized sled‐shape cover glass, 1 which partially covers long edges of the device. According to the patents published by key handheld manufacturers, 2 , 3 we can expect more variety of 3D shaped cover glass for handheld devices in the market. In this study, we have focused on the reliability of 3D cover glass when it is dropped to a rigid surface. The key parameters under study are the corner/edge bend radius and angle of the cover glass, which determines the 3D shape of the cover glass. To achieve this goal, we developed a finite element model to simulate the drop 4 - 13 of a handheld device with 3D‐shaped glass. The model uses explicit algorithm to simulate the high speed impact on the device during the drop test. The glass performance was evaluated based on contact force between the glass and the ground and maximum principal stress in the glass. We showed that to avoid severe damage because of first impact between the glass and the ground, the bend angle of 3D glass has to be in the range between 0 and 45°. For drop angles of 45° and higher, with the proposed glass bend angle, the impact can be taken over by the edge of the back cover of the device. In addition, we showed that optimum glass bend radius is in the range of 3.8 mm and larger. This is required to reduce stress in glass because of impact. The approach and conclusions from the current study can serve as a general guideline to improve the 3D cover glass reliability of a handheld device.     

A novel portable LCD using a new AFFS technology for outdoor readability

Abstract— The advanced fringe‐field switching (AFFS) mode is suitable for portable display devices. It has high transmittance, wide viewing angle, low power consumption, high contrast ratio, and a ripple‐free property resistant to pressure. Recently, a 10.4‐in. XGA prototype which demonstrates excellent transmittance and very good outdoor readability has been developed. To obtain these properties, a new pixel structure has been designed which has a large aperture and a metal embossing pattern for inner reflectance without the use of a black matrix on the embossing metal pattern. Precise control of the liquid‐crystal electrodynamics and surface reflectance using an AR polarizer was achieved. This new panel shows distinguished characteristics for outdoor readability with the backlight on under a bright outside light source.     

机载R分度热电偶玻璃封接式接线座设计

目前在国内机载测温领域,热电偶仍为主流产品,应用广泛.其稳定准确的信号输出对保证发动机控制系统的正常工作至关重要.为此,设计了一种基于玻璃与金属封接技术的新型高可靠性接线座,可用于机载各分度热电偶信号输出的连接.针对R分度热电偶,对接线座进行了适应性设计,有效解决了选用常规接线柱作为信号输出端口时所暴露出的接线柱强度与热电动势匹配之间的矛盾问题.测试结果表明新型玻璃封接式接线座具有耐高温、防松动、密封性好、抗拉抗扭性强、绝缘性能优良等特点,能够在航空发动机高温、强振动等恶劣环境下可靠工作.     

Dynamics behavior of flat glass panels under impact conditions: Experiments and numerical modeling

Response of brittle plate‐like structures such as glass panels to impact loads has been the subject of many research studies. Different compositions of glass are used in wide variety of applications in daily life. Of interest in this study are the glass panels that are used in consumer electronics devices such as mobile phones, tablets, and televisions that help to protect the displays from every day wear and tear. Therefore, the requirement of this glass to resist scratches, drop impacts, and bumps from everyday use leads to the importance of investigation of the glass response under dynamic impact loading. Ball drop test is a widely accepted test for impact reliability in the industry. The test specifies the impact energy threshold as a qualification and prediction metric. Use of energy as the key parameter in impact testing is limited, because it does not account for the time spent in contact during the impact event. This study attempts to establish a reliable metric for impact testing based on a momentum change. The deformation and the strain of the glass will be obtained by the digital image correlation system, while the rebound velocity will be measured with the high‐speed cameras. The global and local measurements are conducted to verify the accuracy of the experimental results. Finite element analysis is conducted using ABAQUS to provide a comprehensive understanding of the dynamic response of the glass. Constitutive relationship for a tape, a hyperelastic material, is developed in this study. Good correlation in deflection time history is obtained between the measurements and predictions.