[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

Causes of crosstalk in simple-matrix LCDs have been analyzed from the viewpoint of drive-signal waveform distortions A new driving method has been developed to reduce these distortions In this new driving method, the “scanning-line-negative-feedback” (SNF) method, the drive signal distortion from scanning electrodes is detected and it is used to control the power supply voltage for liquid crystal operation using a negative feedback technique It has been confirmed that most of the crosstalk can be eliminated from super-twisted LCDs

View full abstract

Full-color projection display with one million pixels has been developed and the optical system has been simplified by using conventional OHPs. This display uses a nematic-cholesteric phase-transition (NCPT) liquid crystal panel with a micro-color filter placed outside the panel This simple configuration provides a color OHP display with high performance and low cost One picture element of this color-projection display consists of 9 pixels in the NCPT black and white panel. Thus gray scale is also obtained by dithering using the 9 pixels, resulting in a full-color projection display The contrast ratio of 5 : 1 and the line-addressing time of 2.2 msec were achieved

View full abstract

The problem of pixel voltage shift for TFT-LCDs due to a gate-source capacitance coupling (C_gs) of a-Si TFT becomes more severe in high resolution LCDs. This problem can be moderated through diminishing C_gs using a self-alignment structure. The self-aligned a-Si TFT process can be simplified by using an ion-doping technique to form source/drain contact regions. The mobility of this ion-doped self-aligned a-Si TFT was 0.35 cm²/V·sec and the threshold voltage was 2.3V. The ON/OFF ratio was over 10⁶ in the dark over 10⁵ under 2000 lx light illumination. These characteristics were sufficiently stable under gate stress. The authors have developed 9-inch TFT-LCD panels with this new self-aligned a-Si TFTs. These LCDs show fairly good image. These data show that ion doping technology is very effective for improving 2-Si TFT-LCDs.

View full abstract

We have developed a 15-in. TFT array fabrication process that assures a high production yield for workstation applications.
In order to minimize signal delay in our LCDs, we used aluminum for the gate and the source bus-lines.For the gate lines, an aluminum-silicon alloy with a chromium-overcoat was employed to suppress hillock formation. As for the source lines, a titanium barrier was used to prevent aluminum diffusion into the semiconductor layer.
In order to reduce the possibilities of open and cross-over short defects, we have developed gate aluminum-silicon alloy and contact hole tapering processes. Furthermore silicon-nitride and tantalum-oxide double insulators were employed.
By utilizing this process, a 15-in. full-color TFT-LCD consisting of 1152×900 pixels has been successfully Placed into production.

View full abstract

We propose a direct-view TFT-LCD with a wide viewing-angle which uses a polymer-dispersed liquid-crystal panel and a pair of polarizers. We call this device a polymer-dispersed LCD with crossed Nicols (PDN). The PDN allows panels to be made with low scattering levels.This suggests the use of fluorinated liquid crystals (F-LC) that show a high voltage-holding ratio in TN-LCDs. We found that F-LCs show good solubility with resins having low solubility parameters. A voltage-holding ratio of over 98% is shown, which is almost equal to the value for TN-LCD. The vertical viewing range exceeds ±60°, with a contrast ratio of over 5 and no image reversal. The range is almost three times the TN-LCD value. Molecular alignment is symmetrical and the variation of overall retardation is suppressed. The TFT-LCDs fabricated show a high contrast ratio and no imag reversal at any viewing angle.

View full abstract

An in-process inspection method to detect electrical defects on an active-matrix LCD panel is proposed The present functional test of pixels utilizes an optical change sensing technique The proposed inspection system can identify the location and the type of line and point defects on an LCD panel, before the final assembly, by using a near infrared laser in a nondestructive manner with high spatial and voltage resolutions It can also estimate thin film transistor characteristics such as switching time, threshold voltage, and channel conductance

View full abstract

A large-area high-resolution TFT-LCD is fabricated using a step-aligner, because it's screen size exceeds the photo-mask size A shot-block boundary is sometimes perceived and deteriorates picture quality. The purpose of this paper is to investigate the shot-block perceptibility and the influences to TFT-LCD pixel design, theoretically. A new model with a level-shift voltage induced by a TFT parasitic capacitance has been introduced and an estimation of the currently available step-aligners, which have a maximum pattern-discontinuity of 1.2-1.5μm, showed that they would cause the shot-block images. A generalized design rule related to the shot-block image has been introduced. Using this rule, the aperture ratio of high-resolution TFT-LCDs were estimated and the results showed that the aperture ratio would decrease, as the number of gate lines increased. Possible methods to improve this phenomenon have been summarized.

View full abstract

The Space Modulated FRC (Frame Rate Control) method is widely used to realize a multicolor TFT-LCD This method produces intermediate gray shades by switching the efective voltage applied to the LCD from frame to frame. The conventional FRC, however, had the problem of flickering which depends on the specific image pattern Therefore, we have developed a new Adaptive Space Modulated FRC method of automatically generating the optimal timing for voltage switching from the display data As a result, we have realized a flicker-free, 16-gray shades, 4096-color display using the new FRC and an eight-level driver.

View full abstract

A new low image-lag digital liquid crystal TV has been developed. In conventional LCTVs, image lags occur due to the low response time of a liquid crystal material. Using the new low image-lag drive method (L. A. O) that emphasizes moving parts of the image, the response time was improved from 60 ms to 17 ms, or in other words, 40% to 10% in terms of an image-lag after one field, which is sufficient for TV specifications. This method also improved the vertical resolution degraded by an intra-field interpolated-type non-interlaced drive method. In addition, in order to reduce noise produced by this method, a noise reduction method has been proposed. This method has a motion detector and the L. A. o method works under the condition that moving images are detected. Using this method, the maximum improvement in S/N ratio was about 10 dB. As a result, a high-image quality 10.4 inch LCTV has been developed. The brightness was 400 cd/m² and we can see images even in an illuminated room.

View full abstract

This paper introduces a newly developed portable prompter which is based on a 10-inch active-matrix monochrome backlit LCD. This prompter consists of an ordinary laptop computer, a 10-inch TFT-LCD, and a partially reflective plastic plate.
Lecturers can easily read the text reflected by the plastic plate because of the LCD's high contrast, fast response time, and bright back-lighting.
The audience can see the lecture notes without distortion because the reflectivity of the plastic plate is 20%, so 80% of the light passes through it. The system features convenient functions such as page down/ up, scrolling display with controllable speed, adjustable plastic plate position, and adjustable LCD back-lighting brightness.
This system is useful to both lecturers and audiences as shown by subjective evaluation experiments. It will be widely used for various kinds of presentations in the near future because it is portable and easy to use.

View full abstract

This paper introduces a newly developed electron beam simulator for CRTs with axi-asymmetric electron guns. Effects of space charge, thermal spread, and deflection defocusing were all taken into consideration in the development process.
In this simulator, the electron beam is divided into Gaussian beamlets, with each having a main trajectory and paraxial trajectories around it. For calculating the electrostatic field in the main lens, the multipole field expansion method was used together with the surface charge method to reduce CPU time and to simplify data input for complicated electrodes.
The simulator was used to investigate dynamic astigmatism correction using a quadrupole lens in the main lens, and the cancellation of an astigmatism using slits and square apertures in the beam-forming region. Calculations of the beam spot diameters closely matched the actual measurements (differences were 10% at most). This test confirmed the simulator's effectiveness in investigating and designing CRT axi-asymmetric electron guns.

View full abstract

This paper introduces a new system which compensates for low frequency magnetic field leakage from color CRTs without significant deterioration in the CRTs quality.
The system consists of two isolated closed-wire loops and a cylindrical ferrite core installed at the horizontal lead wire. One portion of each loop is wound around the ferrite core and another portion is mounted on the deflection yoke.
Current is brought about in each loop by electromagnetic induction of the flux from the lead wire. This generates the compensation field.
By using this system, the compensating power can be suppressed to 3% of the horizontal deflection power. Moreover, the picture screen quality deterioration disappears because of the compensation field distribution arrangment in the deflection region.

View full abstract

A high-intensity flat vacuum fluorescent lamp utilizing cathode-luminescence has been developed for LCD backlighting. The apparatus used was a glass vessel consisting of two concave-shaped pieces of glass with two mesh-shaped grid electrodes and the line cathodes fixed at the solder glass fritting seal section between the front and rear pieces of glass. The lamp consists of tetrode. The glass vessel is made of Barium-Strontium glass, so that a high voltage can be applied to the anode and so that a high luminous efficiency can be obtained. As we adopt an interference filter and a liquid-cooling system to add high power to the phosphor layer, this lamp can produce an intensity of 70, 000 cd/m² (Green). Moreover, excellent results concerning brightness uniformity, brightness control and temrperature stability are also obtained.
This lamp is expected to be used for LCD backlighting of LC projectors and for head-up displays of cars and planes.

View full abstract

Usually we place three kinds of monochromatic cells side-by-side to create a multicolored panel, because we cannot change the luminous color of a discharge using conventional methods. However, our technique involving color-controlled discharge can change it into three colors. In this paper we describe the results of the trial manufacturing of three-color panels using our new technique. We use neon spectra as the red color, visible spectra of mercury as the blue, and fluorescence excited by 253.7 nm HgI as the green. These colors are controlled by pulse rise time, width, and frequency. We made a panel with 5×7 dots capable of displaying alphabets and Arabic numerals in three colors The color difference between blue and green is not distinct enough and its maximum brightness is about 500 cd/m² for each color. The electric power source voltage required was about 500 volts

View full abstract

This paper discusses a newly developed 4 7-inch diagonal white light emitting TFEL display panel with 320×240 dots and a SrS Ce, Eu phosphor layer Luminance of 520cd/m² and luminous efficiency of 025 lm/W at V_th+60V were obtained using a 1-kHz pulse drive, with V_th being the threshold voltage The estimated response time is 30 ms, which is almost the same as that of a ZnS : Mn TFEL device Therefore, this response time is fast enough for matrix display application Multi color display encompassing eight colors is possible by combining this device with color filters.

View full abstract

A highly sensitive x-ray image pickup device has been developed based on the gadolinium phosphor and phthalocyanine organic photoreceptor conversion method for radiation images. As compared with the screen-film combination used routinely in medical and industrial fields, sensitivity is nearly 10 times higher.
The prototypr camera has a 10x10-cm image plate that consists of gadolinium phosphor and phthalocyanine photoreceptor laminated layers together with a corotron charger and a toner developer. This portable camera is capable of taking series of x-ray photographs at various energies in a short time.

View full abstract

Although originally developed for aircraft use, head-up displays (HUDs) have recently found application in automobiles.
Studies of HUDs in aircraft shows that HUDs are superior to head-down displays in terms of aircraft operation and that this superiority stems from reducing pilot eye accommodation and eye movement.
Focusing on the driver's peripheral vision, we have done two kinds of experiments to examine what makes automotive HUDs superior. One examines how the recognizability of HUD images declines when peripheral vision is not available ; the other evaluates how much displayed image information can be obtained through peripheral vision.
We have concluded that peripheral vision plays an important role in recognizing of HUD images presented at a small depression angle and a long distance. The contribution by peripheral vision to the recognition of displayed images can be of equal importance to that of reduction of eye accommodation and eye movement.

View full abstract

Analyzing eye movements facilitates objective evaluation of the interest an image evokes. Moreover, how viewers areas of individual interest and attention differ can be clarified by simultaneously displaying multiple viewers' eye movements. To date, however, there has been no experimental system that enables us to do this. This paper introduces a binocular eye-movement analyzer for use with multiple viewers which measures and displays four viewers' eye movements simultaneously in real time. A 3D Hi-Vision display unit, developed for vision experiments which uses this new analyzer is also discussed. Furthermore, we compare eye-movement data which is collected when viewers are shown 3D and 2D images. As a result, we show that fixation position, duration, and speed of the left and right eyes differs for both 2D and 3D images. We also show that these differences are qualitative and that vergence distribution is wider in 3D images than in 2D images.

View full abstract

We have developed a 2000-line TV camera which use a 1-inch SATICON as a real-time digital radiography (DR) system
We record a 60% amplitude response when 1000 TV lines are at the center of the image, and a 46 dB signal-to-noise ratio using the 2100 line scanning mode at a signal current of 550 nA

View full abstract

Superposition of complex fields generated by a hologram and its intensity detections facilitate parallel optical logic operations Coherent lights must be used for inputs, since this holographic logic operation is based on coherent optical processes Therefore, coherent input devices are required for parallel optical computing Three important properties of these coherent input devices are contrast, amplitude deviation, and phase deviation. In this paper, we discuss the tolerance limits of these three properties Experiments using a liquid crystal display as a coherent input device are studied.

View full abstract

[in Japanese]

View full abstract