A new and simple light-pen position-detection technique for interactive plasma-display systems

The plasma panel is a 2-level type of display possessing local memory, high luminance, and selective write-erase capability. There are, however, no convenient inexpensive methods for interacting graphically with material displayed on a panel by means of a hand-held stylus. A simple and potentially low-cost technique has been developed in which a light pen can be used to point at any part, dark or light, of a plasma panel, thus making an economical interactive plasma-display system possible. The technique is based on the ability to selectively address one cell of the panel with a sequence of two interrogating pulses. Therefore, depending on the state of the addressed cell, one or the other interrogating pulse will cause the addressed cell to flash at a time different from all other cells, without altering the state of the addressed cell or disturbing the unselected cells. The light pen is gated to look for these light pulses and their individual Phase in order to establish the location of the light pen and the state of the cell. The operating margins for the interrogating pulses exceed the panel's own write-erase margins, and the additional hardware required beyond the normal panel sustain and select circuitry is negligible.     

Multiple states and variable intensity in the plasma display panel

The plasma display panel, in its usual mode, retains information in the form of wall charges that determine whether or not a sequence of discharges will be maintained at a given cell. These discharges are stable in the sense that a perturbation in wall voltage at a particular discharge will damp out over the succeeding discharges. Recent work has shown that a cell in a plasma display panel can exist in one of several states, each with a unique set of wall voltages and each with a unique average intensity. As with the bistable case, each state is stable in the sense that perturbations damp out. Three states have been achieved simultaneously, with brightnesses that can be characterized as bright, medium, and dim. Within the constraints of a simple theoretical model, the conditions for stability can be stated in terms of the products of the slopes of charge transfer curves. This technique for achieving variable intensity retains the advantage, inherent in the plasma display technique, that the information, once imparted to the display, is retained as long as the sustaining signal is applied to the entire panel.     

A real-time curve tracer for the AC plasma display panel

A minicomputer-controlled system is used to automatically measure the wall charge transfer curve of a single cell in an ac plasma display panel. Curves can be plotted on a graphics display as fast as 5/s which allows real-time interaction with the user. The measurement technique is based on the ability to directly measure the wall charge from a single cell. The minicomputer controls the sustain voltage across the cell and obtains the resulting wall charge. It then does the tedious algebra needed to complete the transfer curve. The measured curves show numerous interesting effects. The influence of the state of the neighboring cells can clearly be seen. The duty factor of the sustain waveform has a strong influence on the transfer curve. An effect dependent on sustain frequency is presented that shows a transfer curve region with negative slope. The most interesting effect measured is a hysteresis in the transfer curve, in that a different curve is traced out as the cell goes from off to on than when it goes from on to off.     

A solid-state matrix-addressed display

Cadmium selenide (CdSe) switches have been devised to control the luminous emittance of electroluminescent cells in a solid-state display. The technique employed makes use of the hysteresis in CdSe to change the resistance of the material to some low value when a switching voltage is applied. In its low-resistance state, the CdSe switch can energize an electroluminescent cell connected in series with it. By wiring the cells in rows and the switches in columns, a display panel results in which each cell-switch combination can be individually addressed by energizing the appropriate row and column. This paper describes the principles of operation and outlines the construction techniques for this display. Performance characteristics of a 100-unit display panel are discussed. This panel, with 20 lines per inch resolution, has been operated with addressing pulses of 25 microseconds duration, providing an output brightness of 20 footlamberts. The construction process is adaptable to mass production, resulting ultimately in low cost. The display has memory thus allowing random access, and operates on very little power. Demonstration of this display represents a significant advancement in the state of the art. This small display possesses the characteristics necessary for development of practical large-area displays.     

An advanced sustaining technology for plasma display panel using voltage-balancing method

A cost-effective plasma display panel (PDP) sustainer employing current injection method (CIM) for energy recovery is proposed. Using a voltage-balancing technique, driver cost can be reduced by about 20%-30% compared with that of the conventional H-bridge driver by using low-voltage switches. The energy recovery performance can be improved by the current that is built up before the energy recovery operation. This buildup current is utilized to change the polarity of the panel electrode and provides additional variable to determine pulse slopes. Experimental results show that the voltage stress of switches connected in series is identically clamped to sustain voltage during sustain operation and that light is emitted more stably by independent control of the rising and falling slopes using CIM. Therefore, the proposed sustainer is expected to be suitable for a low-cost PDP sustaining driver requiring stable discharge characteristics.     

LSI-Direct-controlled plasma display panel

A plasma display panel with auxiliary discharge cells to control the display cells has been developed. The panel can be directly controlled by low-voltage MOS-LSI switching circuits.     

Ternary operation of the plasma display cell

The plasma display cell, in the normal mode, operates as a bistable ON-OFF element. Under certain conditions, by applying the appropriate sustaining signal, the cell can be maintained in one of several possible ON states that can be distinguished from each other by the light or current output of each state. Conditions on a class of sustaining signals that can sustain the cell in two ON states and an OFF state are described.     

Realization of Flexible Plasma Display Panels on PET Substrates

DC plasma display panels are fabricated on flexible polyethylene terephtalate (PET) substrates. Each pixel consists of laterally placed anode and cathode electrodes. All electrical elements are formed on a single PET substrate, whereas a second substrate is needed to encapsulate the panel. Silver is used as the metal for each electrode and standard photolithography is used to form each cell. A 150-/spl mu/m-thick layer of a UV-curable polymeric adhesive was used to form barrier ribs to both electrically isolate neighboring cells and to encapsulate the plasma. Conversion of vacuum UV into visible light is possible by blast-embedding of proper phosphor grains into the top substrate. The current-voltage and turn-on voltage versus pressure characteristics are examined. Effect of curvature on turn-on voltage is addressed.     

适合产业化的显示屏化学减薄工艺的研究

超薄显示技术已成为市场的一种主流趋势。本文利用刻蚀后清洗的间歇式工艺研究了显示屏半成品的化学减薄。在光刻胶和边框胶保护下,调整氢氟酸浓度,加入一定量的硝酸、浓硫酸和盐酸,并添加超声辅助条件,刻蚀速率明显提高。通过交替的清洗工艺有效地降低了表面粗糙度,并减少了表面白色附着物的沉淀。显示屏厚度从0.8mm减薄到0.3mm,基板表面粗糙度为11.32nm,厚度均匀性为4.76%。设计的间歇式减薄工艺可以应用到现有的显示屏生产工艺中,为制作超薄液晶显示屏和超薄有机发光显示屏提供了一条可行的方案。     

The effect of the discharge aging process on the surface state of MgO film in AC PDPs

This paper reports on the change in the surface condition of the MgO thin film in an ac plasma display panel during the discharge aging process. The superficial layer on the MgO thin film was created during the discharge aging process, which was related to the minimum sustain voltage and the light intensity emitted from the Neon+Xenon gas mixture discharge. The superficial layer on the MgO thin film was observed using a transmission electron microscope. The X-ray diffractometer pattern of the MgO thin film after the discharge aging process was different from the pattern at the beginning of the discharge aging process.     

A driving method for high-speed addressing in an AC PDP using priming effect

A novel driving method is proposed to reduce the addressing time in an ac plasma display panel. In this method, priming discharges are used to achieve high-speed addressing without adding an auxiliary electrode. Some of the scan lines were used to provide the priming particles for the reduction of the address discharge time lag (t/sub d/) in the adjacent scan lines. The number of priming electrodes was optimized and two different types of priming discharge were tested in order to reduce the inherent light output caused by the priming discharges. In the panel experiment, the t/sub d/ was reduced to one half of that of the conventional method when the priming particles were provided and the background luminance was reduced from 4.97 to 2.94 cd/m/sup 2/ through the reduction of the number of priming electrodes, and further, by changing the type of the priming discharge while the peak luminance could be improved more than twice by allocating the saved-time-to-display period, which in turn, resulted in a higher contrast ratio.     

The current injection method for AC plasma display panel (PDP) sustainer

A new concept of energy recovery for a plasma display panel (PDP) is proposed. Different from conventional LC resonant sustaining drivers, the current built up before inverting the polarity of the panel electrodes is utilized to change the panel polarity together with energy previously charged in panel capacitance. This operation provides zero-voltage switching of switches and reduction of electromagnetic interference by rejecting the surge current when the sustain switches are turned on. The buildup current helps to reduce the transition time of the panel polarity and may produce more stable light waveforms. This method is suitable for a PDP sustaining driver requiring stable light emission characteristic while it maintains low circuit loss like the series-resonant-type energy recovery circuit which is known to be a very effective method.     

Improved 40-inch plasma display for wall-hanging HDTV receiver

A new 40-inch-diagonal color dc plasma display panel (cell pitch: 0.65 mm, 800×1340 cells) with both a resistor-in-cell structure and a phosphor screen on the side wall and bottom of the cell has been developed through the improvement on the large-area panel fabrication technologies. Stable HDTV pictures have been experimentally reproduced on a compact display using the new panel and pulse memory drive circuits. The peak white luminance is 150 cd/m². The lifetime of the 40-inch panel is expected to be over 30,000 hours, judging from the results obtained using a medium-sized panel under the same conditions     

Cost-Effective Zero-Voltage and Zero-Current Switching Current-Fed Energy-Recovery Display Driver for ac Plasma Display Panel

A new cost-effective zero-voltage and zero-current switching (ZVZCS) current-fed energy-recovery display driver for a plasma display panel (PDP) is proposed. It features a simpler structure, less mass, and lower cost of production. Furthermore, since all power switches are turned on or off under zero-voltage or zero-current switching, it has several favorable advantages such as an improved electromagnetic interference (EMI), low switching losses, and reduced burden on the cooling system. Particularly, since the current source built in the inductor can compensate the large gas-discharge current, main inverter switches have the reduced current stress and turn-on timing margin. Therefore, the undesirable voltage notch problem caused by the improperly controlled gate signal can be solved, which enables the panel to light at lower voltage such as 143 V compared with about 165 V of the prior circuit. To confirm the operation, validity, and features of the proposed circuit, experimental results from a prototype built with 6-in test PDP are presented.     

基于LabVIEW的光敏电阻自动测试系统

基于LabVIEW的光敏电阻自动测试系统是由555定时器和光敏电阻构成的多谐振荡电路,把对光敏电阻阻值的测量归结为频率的测量,结合LabVIEW采集电路实现电阻对频率的测量,并自动完成测量值转换成电阻值以及显示而制作的一套完整的自动测试系统。系统通过外置LED灯作为光源,控制其电压的变化使输出光强发生改变,从而使电路中光敏电阻阻值发生变化,继而引起输出信号频率发生改变,通过LabVIEW采集卡采集,自动测试、记录并处理分析得出某个频率下对应的光敏电阻阻值,并对这些器件的性能进行研究并以曲线显示出来。     

Characteristics of discharge pattern in surface-discharge AC plasma display panels

A two-dimensional computer simulation for the surface-discharge ac plasma display panel shows that the suppression electrodes perform the function of confining the discharge area within a unit cell. This is due to the effect of the suppression on the surface potential caused by the ion or electron accumulation on the dielectric protecting layer rather than the pinch effect on the electric field. The investigation of the effects of various panel dimensions on the discharge pattern resulted in discovery of an analytical relationship that can be used to determine whether the discharge pattern is a criss-cross or single-sided one for given panel dimensions. The formation mechanism of the crisscross discharge pattern was clarified from the consideration of the computer simulation and the computer-aided image processing of the discharge pattern from an experimental surface-discharge ac plasma display panel.     

A new method to reduce addressing time in a large AC plasma displaypanel

To replace the dual scan system by single scan in large ac plasma display panel (PDP), the addressing time should be reduced by modifying cell structure and/or driving circuits. Moreover, the luminance of the PDP can also be increased with the decrease in the addressing time. In this paper, we suggest the bus and address electrodes with triangular protruding tips in order to reduce the addressing time. Moreover, the addressing time of the ac PDP with these electrodes was investigated experimentally with address and display period separated (ADS) driving method. The experimental results show that the addressing time can be reduced more than 30% compared with the conventional type by modifying the electrodes without reducing the luminance of the PDP     

液晶显示屏与电容式触摸屏间的信号串扰抑制

随着显示技术的不断发展,集成触摸屏的液晶显示(LCD)在日常生产与生活中得到了广泛的应用。良好的触屏显示在人机交互方式上扮演着重要角色。然而,外挂式触摸屏在薄化后,触控感测部件和LCD驱动部件之间的距离减小,造成两者之间更紧密的耦合,导致LCD对触摸屏的噪声干扰更加严重,造成误触摸情况发生。为此,我们通过本文研究发现,调节源极数据驱动IC的内置功能及数据信号的驱动方式,可有效改善噪声干扰问题。首先,根据TFT面板阵列的排布,针对性调节源极数据驱动信号,观察噪声干扰的程度。实验结果表明:降低源极数据驱动能力,或更改数据信号的驱动方式为H2Dot时,噪声最大的sub V-stripe画面下的噪声干扰峰值可下降75%。基于上述解决方案,达到了降低噪声干扰的目的,提供给用户更精准、灵敏的触控体验。     

智能型植物工厂光谱监测中的光学膜设计

介绍了一种设施农业中用于光谱监测的光学膜设计,主要利用截止滤波器的组合得到了三种设施农业用光学膜——红光膜、蓝光膜及红蓝滤光膜,红、蓝光中心波长分别在 460nm和660nm,透光带宽约50nm。红、蓝光透光波段根据植物对光谱的需求设定,在实际应用中可根据需要设定其透光的中心波长及带宽。该滤光片可用于制作设施农业及农业研究中的光谱监测单元,该光谱监测单元是将特定的光学膜片置于晶硅光伏芯片上,通过测定光伏芯片的发电量来监测光学膜片预设波段的光强度。     

Measurement of wall charge and capacitance variation for a single cell in the AC plasma display panel

Real-time dynamic measurements are performed on a single cell in a standard commercially available large plasma panel. The measurements determine cell response to variations in address pulses, sustain waveforms, or priming from neighboring cells. The wall-charge measurement indicates the internal dielectric surface charge and the capacitance measurement indicates the existence of a plasma in the gas volume. These measurements have shown that neighboring on cells can cause a large wall-charge transfer in off cells that results in reduced write and sustain voltage margins. Direct wall-charge measurements allows use of a simple technique for determination of the voltage transfer curve of the plasma cell which greatly aids device characterization. The capacitance measurement has shown that a plasma exists in commercial MgO panels for 10-15 µs after the discharge-current peak. The capacitance and wall-charge measurements can be combined to give simultaneous real-time results.