An in‐cell capacitive touch sensor integrated in an LTPS WSVGA TFT‐LCD

This paper discusses an In‐cell capacitive touch sensor and its integration in an LTPS TFT‐LCD with 7‐inch screen size and WSVGA resolution. The operation of the newly developed sensor is based on capacitive coupling between user's finger and the detection electrode on the TFT substrate, and is purely capacitive. The sensors and the sensor driver circuits have been integrated in the TFT substrate of the prototype TFT‐LCD using LTPS technology. The prototype having 256x150 sensors shows advantages such as smooth operation with no touch force, high position accuracy, multi‐touch (10 or more), a thin and light LCD module, high display quality, and thus is suitable for various applications such as cell‐phones, smart‐phones, mobile‐PCs, and automotive‐use displays.     

Development of a high‐resolution RGBW flexible display using a white organic light‐emitting diode with microcavity structure and that of a side‐roll touch panel

In this study, white organic electroluminescent devices with microcavity structures were developed. A flexible high‐resolution active‐matrix organic light‐emitting diode display with low power consumption using red, green, blue, and white sub‐pixels formed by a color‐filter method was fabricated. In addition, a side‐roll touch display was developed in combination with a capacitive flexible touch screen.     

A 23‐in. full‐panel‐resolution autostereoscopic LCD with a novel directional backlight system

Abstract— An autostereoscopic display that shows stereoscopic images with full‐panel resolution has been developed,¹ but it has a problem in terms of unit size. To resolve this problem, a new directional backlight system was developed, and it was applied to a prototype autostereoscopic LCD. The backlight system has two light sources — one for the right eye and the another for the left eye — and an elliptically shaped mirror that controls the direction of light from the light sources. The LCD uses a field‐sequential method which re‐writes an image for one eye and one for the other eye at a frame rate of 120 Hz, and the light sources alternately blink in synchronization with each frame so that the LCD shows full‐panel‐resolution stereoscopic images without flicker. In this paper, the new backlight system is described. The backlight system is effective for large screen such as 23 in. on the diagonal. By using this backlight system, the prototype LCD achieved practible unit size, brightness over the entire screen, and cross‐talk.     

A 470 × 235‐ppi poly‐Si TFT‐LCD for high‐resolution 2‐D and 3‐D autostereoscopic displays

Abstract— We have developed a 470 × 235‐ppi poly‐Si TFT‐LCD with a novel pixel arrangement, called HDDP (horizontally double‐density pixels), for high‐resolution 2‐D and 3‐D autostereoscopic displays. 3‐D image quality is especially high in a lenticular‐lens‐equipped 3‐D mode because both the horizontal and vertical resolutions are high, and because these resolutions are equal. 3‐D and 2‐D images can be displayed simultaneously in the same picture. In addition, 3‐D images can be displayed anywhere and 2‐D characters can be made to appear at different depths with perfect legibility. No switching of 2‐D/3‐D modes is necessary, and the design's thin and uncomplicated structure makes it especially suitable for mobile terminals.     

A field‐sequential‐color display with a local‐primary‐desaturation backlight scheme

Abstract— Field‐sequential‐color technology eliminates the need for color filters in liquid‐crystal displays (LCDs) and results in significant power savings and higher resolution. But the LCD suffers from color breakup, which degrades image quality and limits practical applications. By controlling the backlight temporally and spatially, a so‐called local‐primary‐desaturation (LPD) backlight scheme was developed and implemented in a 180‐Hz optically compensated bend (OCB) mode LCD equipped with a backlight consisting of a matrix of light‐emitting diodes (LEDs). It restores image quality by suppressing color breakup and saves power because it has no color filter and uses local dimming. A perceptual experiment was implemented for verification, and the results showed that a field‐sequential‐color display with a local‐primary‐desaturation backlight reduced the color breakup from very annoying to not annoying and even invisible.     

An on‐line grid‐gaps inspection system for electron‐gun manufacturing

An on‐line grid gaps inspection system (GGIS) for color‐CRT electron‐gun manufacturing has been developed. The measuring principle is based on the digital‐image‐processing technique and incorporates a design of stepping motor motion control. By utilizing the arrangement of stepping path image processing, the measurements for different types of guns and for different gaps on a gun can be effectively executed with higher resolution, and are easily implemented for the purposes of on‐line inspection and statistical quality control. Experimental results show that the system resolution is about 8.5–10 μm and the on‐line inspection index has been improved to about 120 pieces/hour.     

New approaches to process simplification for large‐area high‐resolution TFT‐LCDs

Abstract— Novel process architectures are proposed for fabricating large‐area high‐resolution TFT‐LCDs with a minimal number of process steps. A low contact resistance between Al bus lines and the transparent conductive oxide layer, necessary for large‐area panels, is obtained by inducing a self‐formed inter‐metallic compound layer at the interface without using any additional buffer or capping layers. For enhanced brightness and resolution, a new TFT array structure integrated on a color‐filter substrate, referred to as an Array on Color Filter (AOC) structure, has been developed. Good‐quality TFTs were successfully constructed on the newly developed color filter for AOC within a sufficiently wide process margin. By adopting these novel technologies, a 15.0‐in. XGA prototype panel was fabricated and shows good display performance. Thus, these novel technologies have improved cost efficiency and productivity for TFT‐LCD manufacturing, and can be applied to the development of TFT‐LCDs of extended display area and enhanced resolution, benefiting from the low resistance bus lines, the high aperture ratio, and reduction in total process steps.     

Touch‐screen panel integrated into 12.1‐in. a‐Si:H TFT‐LCD

Abstract— A touch‐screen‐panel (TSP) embedded 12.1‐in. LCD employing a standard existing a‐Si:H TFT‐LCD process has been successfully developed. Compared with conventional external touch‐screen panels, which use additional components to detect touch events, the new internal TSP exhibits a clearer image and improved touch feeling, as well as increased sensing speed using discrete sensing lines to enable higher‐speed sensing functions including handwriting. The new internal digital switching TSP can be fabricated with low cost because it does not require any additional process steps compared to a standard a‐Si:H TFT‐LCD.     

High‐quality direct‐view display combining multiple integral 3D images

This paper proposes a method for combining multiple integral three‐dimensional (3D) images using direct‐view displays to obtain high‐quality results. A multi‐image combining optical system (MICOS) is used to enlarge and combine multiple integral 3D images without gaps. An optical design with a simple lens configuration that does not require a diffuser plate prevents the deterioration in resolution resulting from lens arrangement errors and the diffuser plate. An experiment was performed to compare a previously developed method with the proposed method, and the latter showed a significant improvement in image quality. A method for expanding the effective viewing angle of the proposed optical design was also developed, and its effectiveness was confirmed experimentally. A prototype device of the proposed optical design was constructed using a high‐density organic light‐emitting diode (OLED) panel with 8K resolution and 1058 ppi pixel density to achieve 311 (H) × 175 (V) elemental images, a viewing angle of 20.6° in both the horizontal and vertical directions, and a display size of 9.1 in. In addition, the proposed optical design enabled making device considerably thinner, ie, with a thickness of only 47 mm.     

Recent research and development on 71‐in.‐diagonal color PDPs

Abstract— The World's first 71‐ and 76‐in.‐diagonal ACPDPs with full high‐definition resolution (1920 × 1080), a high luminance of 800 cd/m², and a dark‐room contrast ratio of 1200:1 have been developed using a highly efficient barrier‐rib structure. Also a new MgO protective layer and a film‐type optical filter were developed to improve picture quality. To fabricate large‐sized panels over 70 in. on the diagonal, an improved uniform exposing technology for the patterning of electrodes, a green sheet method for the transparent dielectric layer, and a co‐processed bus and black‐matrix (CPBB) method were used.     

A high‐contrast front‐projection display system optimizing the projected light‐angle range

Abstract— The problem with front‐projection displays is that the screen contrast ratio decreases under bright‐ambient conditions. To overcome this problem, the design of a special screen, composed of the diffuser whose diffusing property shows top‐hat characteristics and a sawtooth reflector, is proposed. The screen diffuses the incident image light arriving at a projection‐angle range that is a lower‐angle range than the viewing‐angle range, and reflects the ambient light out of the viewing‐angle range. In this paper, the projection‐angle range and the viewing‐angle range was optimized to improve the contrast ratio of a front‐projection display. As a result, a special screen with the above‐mentioned diffusing property was realized, and a high‐quality front‐projection display with a high contrast ratio, even in a bright room, was achieved.     

A super‐fine‐pitch screen for rear‐projection TV

Abstract— An advanced screen for use with LCD/LCoS/DMD rear‐projection TV has been developed. A lenticular lens having a pitch of 64 μm has been developed without loss in any other optical property. A 70% black‐stripe ratio was obtained by optimizing the patterning process, which maintains high contrast. As described in this paper, the FC‐Screen manufacturing technology has been further developed.     

A vision system for on‐line inspection of CRT electron‐gun grid gaps

Abstract— A high‐resolution vision system for on‐line measurements of color CRT electron‐gun (E‐gun) grid gaps has been developed. The measurement principle is based on a digital image‐processing technique combined with a multi‐path imaging system. By utilizing the arrangement of multi‐path image processing, the measurements for different types of guns and for different gaps on a gun can be effectively executed with higher resolution. The purposes of on‐line inspection and statistical quality control are also easily implemented. Experiments were executed in the production line of a 15‐in. monitor, and the experimental results show that the system resolution is about 8.5–10 μm and the on‐line inspection index is about 300 pcs/hour.     

Dynamic refresh‐rate scaling via frame buffer monitoring for power‐aware LCD management

In recent years, there has been wide‐spread use of large and high‐resolution liquid‐crystal displays (LCDs) on handheld devices. The portion of LCD power consumption in the overall system has gradually increased. While most of the previous research on LCD power management has focused on the hardware level, practical mechanisms at the software level are hardly known. This paper presents a power‐aware LCD management mechanism, based on dynamic refresh‐rate scaling and frame buffer monitoring. The proposed mechanism guarantees the display quality of service, which is inherently specified by content types. The mechanism does not require additional hardware or modifications to applications. The experiment results—on a commercial PDA with a resolution—show that the proposed mechanisms effectively reduce the power consumption by up to 10%, while satisfying the display quality requirements for the LCD screen. Copyright © 2006 John Wiley & Sons, Ltd.     

Multi‐view 3‐D display employing a flat‐panel display with slanted pixel arrangement

Abstract— A flat‐panel display with a slanted subpixel arrangement has been developed for a multi‐view three‐dimensional (3‐D) display. A set of 3M × N subpixels (M × N subpixels for each R, G, and B color) corresponds to one of the cylindrical lenses, which constitutes a lenticular lens, to construct each 3‐D pixel of a multi‐view display that offers M × N views. Subpixels of the same color in each 3‐D pixel have different horizontal positions, and the R, G, and B subpixels are repeated in the horizontal direction. In addition, the ray‐emitting areas of the subpixels within a 3‐D pixel are continuous in the horizontal direction for each color. One of the vertical edges of each subpixel has the same horizontal position as the opposite vertical edge of another subpixel of the same color. Cross‐talk among viewing zones is theoretically zero. This structure is suitable for providing a large number of views. A liquid‐crystal panel having this slanted subpixel arrangement was fabricated to construct a mobile 3‐D display with 16 views and a 3‐D resolution of 256 × 192. A 3‐D pixel is comprised of 12 × 4 subpixels (M = 4 and N = 4). The screen size was 2.57 in.     

Wide‐locking range LC‐tank divide‐by‐4 injection‐locked frequency divider using transformer feedback

A wide locking range, injection locked frequency divider (ILFD) circuit topology is explored. The modulus‐four ILFD utilizes a cross‐coupled voltage‐controlled oscillator in conjunction with transformer feedback, parallel‐tuned resonator, and two‐segment, series mixers at the injection point. The transformer feedback and two‐segment mixing circuit topology achieves a locking range of 2.7 GHz (14.1 to 16.8 GHz) at an injection point bias of 0.9 Vdc and 0 dBm injection power. Spectral measurements at the ILFD output demonstrate proper phase‐lock operation and expected phase noise reduction using a high quality signal source at the ILFD input. The ILFD is implemented in the TSMC 0.18 μm 1P6M CMOS process, utilizes a die area of 0.839 × 0.566 mm² and consumes 16.56 mW. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:557–562, 2015.     

High‐resolution autostereoscopic 3‐D projection display with a space‐dividing iris‐plane shutter

Abstract— A high‐resolution autostereoscopic 3‐D projection display with a polarization‐control space dividing the iris‐plane liquid‐crystal shutter is proposed. The polarization‐control iris‐plane shutter can control the direction of stereo images without reducing the image quality of the microdis‐play. This autostereoscopic 3‐D projection display is 2‐D/3‐D switchable and has a high resolution and high luminance. In addition, it has no cross‐talk between the left and right viewing zones, a simple structure, and the capability to show multi‐view images.     

Invited Paper: Super Hi‐Vision projection display for next‐generation TV

Abstract— For future broadcasting, NHK is studying new video services offering very‐high‐picture quality achieved through Super Hi‐Vision. Toward that aim, a projection display that has a resolution equivalent to 7680 × 4320 pixels by using four 4096 × 2160 D‐ILA? panels has been developed. The display requires precise convergence adjustment because it consists of two projection units, so an automatic adjustment system was developed. Although the pixel number of the digital camera used is less than that of the display, a 0.2‐pixel accuracy was obtained. This report introduces theaters that use this display as an example of applying the Super Hi‐Vision video system.     

High‐luminance 1‐m‐long plasma tubes for wall displays

Abstract— The plasma‐tube array is expected to realize a wall‐sized display. This method will realize an emissive‐type display with a flexible screen shape and an expandable screen size. The shape of the plasma tube was investigated to realize high luminance, high luminance efficacy, and high flexural strength. As the result, a cylindroid tube is proposed to satisfy these demands. An experimental display of 1 m × 128 mm has been developed with these cylindroid tubes and it demonstrated a high luminous efficacy of 3.1 lm/W.     

Dual‐lenticular‐lens‐based 2‐D/3‐D convertible autostereoscopic display

Abstract— A 2‐D/3‐D convertible display using two lenticular lenses has been developed. It shows 2‐D pictures in full resolution and 3‐D autostereoscopic pictures in half resolution by moving one lens relative to the other. The lens assembly consists of thin metal frames, two lenticular lenses, and two shape‐memory‐alloy (SMA) wires used as actuators. While this assembly is applicable to flat‐panel displays of any kind, its simple structure and low power consumption make it best suited to mobile terminals, such as PDAs and mobile phones. Here, we describe its structure and present evaluation results.