Search

Displays have revolutionized the way we work and learn, and thus, the development of display technologies is of paramount importance. The possibility of a free-space display in which 3D graphics can be viewed from 360° without obstructions is an active area of research - holograms or lightfield displays can realize such a display, but they suffer from clipping and a limited field of view. Here, we use a phased array of ultrasonic emitters to realize a volumetric acoustophoretic display in which a millimetric particle is held in midair using acoustic radiation forces and moved rapidly along a 3D path. Synchronously, a light source illuminates the particle with the target color at each 3D position. We show that it is possible to render simple figures in real time (10 frames per second) as well as raster images at a lower frame rate. Additionally, we explore the dynamics of a fast-moving particle inside a phased-array levitator and identify potential sources of degradation in image quality. The dynamics are nonlinear and lead to distortion in the displayed images, and this distortion increases with drawing speed. The created acoustophoretic display shows promise as a future form of display technology. T.F. was funded through the Japan Student Services Organization (JASSO) Student Exchange Support Program (Graduate Scholarship for Degree Seeking Students). This project was funded by the UK Engineering and Physical Science Research Council (No. EP/N014197/1).

We present a continuous surface-potential-based compact model for molybdenum disulfide (MoS2) field effect transistors based on the multiple trapping release theory and the variable-range hopping theory. We also built contact resistance and velocity saturation models based on the analytical surface potential. This model is verified with experimental data and is able to accurately predict the temperature dependent behavior of the MoS2 field effect transistor. Our compact model is coded in Verilog-A, which can be implemented in a computer-aided design environment. Finally, we carried out an active matrix display simulation, which suggested that the proposed model can be successfully applied to circuit design.

Two in-plane-switching (IPS) super-twisted nematic (STN) cells are proposed for reflective liquid-crystal displays. The IPS 180°-STN cell exhibits a normally black display with a relatively low-operating voltage, fast response time, and wide viewing angle. Potential applications for large screen reflective displays are foreseeable.

Hybrid Poincare beams (HPBs) are a kind of structure field with anisotropic polarizations. Here, we demonstrate an approach to tailor HPBs with arbitrary states, through encoding a single hologram on a liquid-crystal display device along with a stable optical system. The state of the obtained HPB is determined only by the encoded holograms with special design, which means it is not necessary to adjust any optical elements or hardware when generating various HPB states. Moreover, perfect HPBs can also be generated through the proposed scheme. In the experiment, the obtained HPBs are analyzed through a polarizer and a special parameter S3/S0, showing good agreement with prediction. This work opens an insight in encoding single holograms for tailoring arbitrary HPBs and inspires various applications.

Most optoelectronic components and consumer display devices require glass or plastic covers for protection against the environment. Optical reflections from these encapsulation layers can degrade the device performance or lessen the user experience. Here, we use a highly scalable self-assembly based approach to texture glass surfaces at the nanoscale, reducing reflections by such an extent so as to make the glass essentially invisible. Our nanotextures provide broadband antireflection spanning visible and infrared wavelengths (450–2500 nm) that is effective even at large angles of incidence. This technology can be used to improve the performance of photovoltaic devices by eliminating reflection losses, which can be as much as 8% for glass encapsulated cells. In contrast, solar cells encapsulated with nanotextured glass generate the same photocurrent as when operated without a cover. Ultra-transparent windows having surface nanotextures on both sides can withstand three times more optical fluence than comm...

In Appl. Phys. Lett. 67, 1990 (1995), we proposed a particularly simple four‐domain (4‐D) twisted nematic(TN) liquid crystal display(LCD) device, which is composed of two left‐handed and two right‐handed TN subpixels. The two members of each pair of same handedness subpixels are rotated 180° with respect to each other, resulting in four domains that spatially average one another optically to provide a wide angle of viewing with no gray scale inversion. The optical performance of the 4‐D TN LCD was confirmed by studies of a test cell fabricated by a two‐step SiOx oblique evaporation technique. In this article, we report the realization of our four‐domain TN display by a reverse rubbing technique that should be suitable for mass production in the display industry. The optical simulation of our 4‐D TN cell was performed and the effect of disclinations at subpixel boundaries on display contrast investigated. A simple model was developed to evaluate the stability of our 4‐D structure.

A data acquisition and display system has been developed for the study of electron impact ionization of atoms. Parallel data recording permits simultaneous but independent acquisition, analysis, and display of electron energy‐loss spectra from two 180° electron energy spectrometers at single‐detector count rates up to 100 kHz as well as their time coincidence spectra for coincidence rates of up to 1 kHz. The system has sufficient energy resolution to clearly observe the post‐collision interaction energy shift of argon L23M23M23 Auger transition lines for low excess energy. It can acquire data at excess energies simultaneously from threshold to 30 eV for more than one transition, representing an improvement in experimental efficiency of at least an order of magnitude. Real‐time data processing allows for faster experimental optimization and better statistical accuracy of accumulated data. Object‐oriented programming in Windows with an IBM 486 computer was used.

A scanning light pulse technique (SLPT) for the generation of selective chemical images is demonstrated, using a broadly available programmable light source provided by a standard cathode-rays tube computer screen, which supplies two-dimensional micropositioning and intensity modulation. The concept is tested with a metal–oxide–semiconductor capacitor with catalytic gates of platinum and palladium spatially distributed in transversal directions, which produce distinctive response patterns upon hydrogen or ammonia exposures. The nonlaterally resolved images formed by the weighted contribution of the chemically sensitive areas of the gate, subsequently highlighted by the exciting light along its scanning path, retains the ability of SLPT to generate distinctive chemical images.

A general purpose data acquisition and control system for scanning tunneling microscopy (STM) using Visual Basic is presented. This Windows hosted Visual Basic environment is highly desirable for use in STM image manipulation, storage, and printing, but in its standard form is not suitable for most data acquisition and display applications. Many of the inherent limitations in the Visual Basic language have been overcome by the use of direct calls to the Windows Application Program Interface. In this paper, we describe a general Visual Basic STM user interface and control system, and the extensions to the language using the Windows API needed to implement this system.

Double parallel‐aligned nematic liquid crystal cells with crossed directors: one serves as a tunable phase compensator and another as a master cell, exhibits a fast response time, improved viewing angle, reasonably high white‐to‐black contrast ratio, and low operation voltage. The flexibility in choosing an appropriate operation voltage enables the device to be operated at its optimal condition. This operational mode can be used for both color‐sequential projection and direct view displays.

Prototype blue microdisplays have been fabricated from InGaN/GaN quantum wells. The device has a dimension of 0.5×0.5 mm2 and consists of 10×10 pixels 12 μm in diameter. Emission properties such as electroluminescence spectra, output power versus forward current (L–I) characteristic, viewing angle, and uniformity have been measured. Due to the unique properties of III-nitride wide-band-gap semiconductors, microdisplays fabricated from III nitrides can potentially provide unsurpassed performance, including high-brightness/resolution/contrast, high-temperature/high-power operation, high shock resistance, wide viewing angles, full-color spectrum capability, long life, high speed, and low-power consumption, thus providing an enhancement and benefit to the present capabilities of miniature display systems.

A new data‐acquisition and display system has been developed for magnetic domain observation using spin‐polarized scanning electron microscopy. The system is composed of 32 frame memories (512×512×16 bit), an image processor with two high‐speed digital signal processors, and a 1280×1024 pixel color monitor. It has the following capabilities: electron probe scanning control; high‐speed (21 s/512×512 pixel image) computing and recording of two components (Px, Py) of secondary‐electron spin polarization; computing and displaying the averaged Px and Py obtained with repetitive scanning; domain image formation for an arbitrary component from (Px,Py) data (8 s/512×512 pixel image); variable speed scanning to obtain a homogeneous quality image in minimum time, even when secondary‐electron intensity varies due to surface inclination; two‐dimensional display of polarization vector distribution; and angle image of the magnetization direction in both black and white and color representation.

The construction and functioning of a portable alt‐azimuth solar simulator and demonstration model is described. The instrument was designed to be used with a slide projector as its light source, as this is readily available in most labs. An arrangement of movable mirrors and a pivoting window allow the user to simulate a wide range of altitude and azimuth combinations of the sun. Upon insertion of a daylighting device in the window, the intensity, position, and coloration of the redistributed simulated sunlight on the ceiling and walls, as well as the presence and intensity of glare, can be visually inspected. Instrumentation consisting of a photovoltaic cell and a 20 segment bar graph display allow direct read out (in lux) of the illumination levels in the model. The scaling up from the simulator model to a full size room is simple and straightforward.

Two configurations of the phase compensation method are presented to measure the cell gap of a filled twisted nematic liquid crystal display (TN‐LCD). The twist angle of the TN‐LCD can be any value between 0° and 360° and the pretilt angle can be any practical value. The cell gap measured by this method is the true TN cell gap, namely the thickness of the LC layer which is primarily responsible for the TN optics. Due to this reason, the phase compensation method can also be applied to measure the cell gap of a color TN cell. The measurement uncertainty of this method is within ±1%.

A type of light modulator using light-absorbing magnetic fluid has been studied experimentally. The basic operation principle and design of the modulator are addressed. It is shown that the luminance of the device can be modulated by applying a moderate level of electric current to a light-reflecting metal electrode. A high contrast ratio comparable to that of printed material was obtained using a kerosene-base magnetite magnetic fluid with a saturation magnetization of 196 G and a thickness of around 20 μm. Doubling of the luminance from a minimum level takes about 200 ms for a driving current of 80 mA. The operation speed of the cell was found to increase almost exponentially with driving current, suggesting the possibility of motion picture applications.

A television compatible display controller is described which forms the image acquisition and display section of a portable infrared camera. The system is capable of accepting a CCD output signal, digitizing it, performing a digital subtraction of a stored reference frame, and increasing each pixel in size so as to ‘‘fill’’ the display area of a TV monitor.

We demonstrate an integrated, two‐color organic light‐emitting device for flat‐panel display applications. The device utilizes a unique stacked pixel architecture which allows for independent tuning of color and intensity. Each of the two addressable colors is sufficiently bright for video display applications, so that the compact stacked pixel, which maximizes display resolution, may form the basis of a new type of full‐color display.

Ferroelectric electron emission observed under periodic spontaneous polarization switching is the basis for the development of a new type of flat panel display. Electron emission occurs from individually operated ferroelectric domains. It is shown that ferroelectric displays may be fabricated in ‘‘plane‐to‐plane’’ geometry which is not possible for field emission displays.

A particularly simple four‐domain (4‐D) twisted nematic (TN) liquid crystal display (LCD) device is proposed, which is composed of two left‐handed TN and two right‐handed TN subpixels. One of each pair of same handedness subpixels is rotated 180° with respect to the other, resulting in four domains that spatially average one another optically to provide a wide angle of viewing with no gray scale inversion. The detailed fabrication process is presented for a two step SiOx oblique evaporation technique used to realize this 4‐D TN LCD. A reverse rubbed polyamide fabrication process has also been successfully used and will be presented in the full length article. Here we present the complete viewing angle and contrast ratio data for a simple and successful 4‐D TN LCD cell.

Optical properties of stretched Mylar films [poly(ethylene terephthalate)] were evaluated. Similar birefringence dispersion to liquid crystals over a wide spectral range makes Mylar an attractive phase retardation plate for display applications. Two display modes employing an antiparallel (or π) and a parallel‐aligned cell with a Mylar phase compensator were demonstrated. The film‐compensated π cell shows an 80:1 black‐to‐white contrast ratio, 60 Hz frame rate and ±45° viewing angle, and is attractive for direct view display. The film‐compensated parallel cell shows an 85:1 black‐to‐white contrast ratio, 180 Hz frame rate, and ±10° viewing angle, and is suitable for projection display.

We studied the electro‐optical response of a bistable cholesteric texture (BCT) display to ac voltage pulses. The material can be driven into states where planar and focal conic textures coexist at zero field and gray scale memory is achieved. According to the properties of the BCT display we designed two drive schemes; one for binary operation and the other for gray scale operation. We made a 320×320 pixel reflective display with a resolution of 80 lines/in. on a passive matrix. Measurement in an integration chamber showed that the display has higher contrast and better viewing angle than a reflective super twisted nematic display.

The three‐dimensional simulation of the liquid crystal director deformation profile and the electric field distribution for the twisted nematic liquid crystal display has been carried out for the first time. The result gives us a complete understanding about liquid crystal deformation profile inside a pixel and the locus of the disclination line pair across the entire pixel area. This would not be possible in the case of the two‐dimensional (2D) simulation [A. Lien, Proceedings of the 10th International Display Research Conference (vde‐verlag gmbh, Berlin und Offenbach, 1990), p. 248; G. Haas, H. Wohler, M. W. Fritsch, and D. A. Mlynski, ibid., p. 252; A. Lien and R. A. John, IBM J. Res. Devel. 36, 51 (1992)], since the 2D simulation result is accurate only for the region which is far away from the corner area of a pixel.

We propose a photonic switch employing a blend of host banana-shaped liquid crystalline molecules and guest photoisomerizable calamitic molecules. The material exhibits a change in the sign of the dielectric anisotropy switching from positive to negative, at a certain crossover frequency of the probing field. The consequent change in electric torque can be used to alter the orientation of the molecules between surface-determined and field-driven optical states resulting in a large change in the optical transmission characteristics. Here, we demonstrate the realization of this feature by an unpolarized UV beam, the first of its kind for banana-shaped molecules. The underlying principle of photoisomerization eliminates the need for a second driving frequency. The device also acts as a reversible conductance switch with an order of magnitude increase of conductivity brought about by light. Possible usage of this for optically driven display devices and image storage applications is suggested.

Viewing angle characteristics of a twisted nematic (TN) liquid‐crystal display (LCD) have been improved by inserting a planar aligned cholesteric liquid crystal compensating layer between the TN cell and a polarizer. Dependencies of the electro‐optical characteristics of the novel LCD on the retardation, ratio of thickness to the pitch (dc/p) and twist‐sense in the cholesteric layer are discussed. A thin‐film transistor addressed LCD with a wide viewing angle has been developed based on this novel cell construction and its display performance is reported.

We describe a new type of color display consisting of polymer‐dispersed droplets of chiralliquid crystal having negative dielectricanisotropy. In the field‐off state, the dropletsscatter light randomly. In the field‐on state the droplets selectively reflect a bright color. Measurements of reflectivities and switching times are presented and we discuss possible applications.

The capacitance‐voltage (C‐V) technique is proposed as a method for characterization of the electrical properties of alternating‐current thin‐film electroluminescent (ACTFEL) display devices. Analysis of the C‐V and aging characteristics of ZnS:Mn ACTFEL devices indicates that the C‐V technique is complementary to the charge‐voltage technique in the extraction of device physics information.

We report solution-processed low-voltage zinc-tin-oxide (ZTO)/zirconium-oxide thin-film transistors (TFTs) possessing a field-effect mobility of ∼10 cm2/Vs, a threshold voltage of 0.1 V, and an on-off current ratio of ∼1 × 109. These TFTs exhibit very small hysteresis windows in both dark and illuminated conditions. We also investigate the photo stability combined with prolong negative bias in these devices. Large threshold voltage shifts and sub-threshold swing degradation typically observed in ZTO TFTs are not present in our devices. We believe that these device characteristics, which stem from the electronically clean semiconductor-dielectric interface, satisfy the requirement for high quality and low power-consuming transparent displays.

We report high performance reflective color filters based on one-dimensional metal-dielectric multilayer. Wide viewing angle of ±50°, far beyond that with conventional all-dielectric multilayers, is achieved while maintaining approximately 100% peak reflectance and color reproducibility. Reflectance of 40% in white mode and color gamut of 47% to the United States National Television Systems Committee (NTSC) standard is demonstrated. The proposed color filter is integrated into 3.5-in. color reflective display and shows 30% increase in brightness than conventional dye color filters.

Three-color electrowetting (EW) reflective display devices have been achieved using a vertical stack structure with colored oils. Fundamental properties (interface tension and geometry) of the EW process were investigated. Arrays of ∼1000–2000 pixels were constructed with pixel sizes of 200×600 and 300×900 μm2. Each color layer can be switched independently. Open (oil-free) area fraction of ∼80% in each cell is achieved at ∼10–12 V. Switch-on times range from 5 to 15 ms, suitable for video content display. These characteristics demonstrate that the EW vertical structure has the potential to produce attractive video-speed color reflective electronic paper devices.

Meteorological measurements of surface pressure to better than 1 mbar are routinely required in surface pressures of typically 1000 mbar, and detecting small pressure changes is important for forecasting. An inexpensive pressure sensor provides the basis of a barometer suitable for such general meteorological use. Signal-conditioning circuitry has been added to allow typical surface sea-level pressure variations to be resolved to 0.1 mbar using a ±5 V 12-bit analog to digital system. The sensor excitation voltage is shown to track the sensor’s temperature closely, and this is extracted to provide a temperature-compensation signal. When combined with a nonlinearity correction system and a digital display, this gives a portable barometer capable of reading to ±0.5 mbar (over the range of 930–1020 mbar) for temperatures between 0 and 25 °C. The final display reading includes the temperature compensation by using a panel meter in ratio mode.

Interference effects in top-emitting organic light-emitting diodes (OLEDs) containing an air gap of 15 µm are studied over a range of angles in order to obtain information about the spatial coherence properties. The devices display effects similar to a Fabry-Pérot Étalon illuminated by a source with a broad spectral range, but the interference effects diminish rapidly with angle, which is inexplicable with simple thin film optics. The results suggest that this effect is due to the spatial coherence of the OLED. From an analysis of the interference pattern a number of device parameters can also be determined.

Unlike previous high-contrast devices that all involve inserting extra layer(s) with optical purposes (e.g., absorption and interference) into the active region of devices, in this-letter we report a high-contrast top-emitting organic light-emitting device (OLED) that utilizes only optical characteristics of electrodes and anti-reflection coatings deposited outside the active region, thus reducing the complexity of devices. Furthermore, the device has an inherent microcavity which is beneficial to electroluminescence efficiency. The devices are readily compatible with the processing of active-matrix backplanes, and active-matrix OLED displays incorporating such high-contrast top-emitting devices were demonstrated to have improved readability under a strong lighting environment.

We have investigated how bus electrodes affect discharge and luminous characteristics of a discharge cell. Three-dimensional simulations have been performed in a coplanar structured alternating current plasma display panel cell, with phosphor saturation effect taken into account. There exists the optimal position of bus electrodes for high luminance and luminous efficiency. Considering bus electrode thickness, we have found that in-bus structure is a promising candidate for high luminance, high luminous efficiency, and fast operation plasma display panels. Our simulation results would be very useful to understand the influence of bus electrode on characteristics of a plasma display panel cell, and would also provide a general guidance to improve its display performances.

In the split‐beam method, accurate measurement of the liquid crystal display cell gap requires determining the interference fringe order correctly. One method to determine the orders is the so‐called intensity method in which the brightest fringe is determined to be the zeroth order. Using this method, the measurement accuracy may be affected by random noise. The color method in which the order of the fringes is determined according to their colors is presented. It is easy to get much better measurement accuracy by using the new method.

In order to understand the discharge characteristics in an alternating current plasma display panel (ac PDP) and optimize it further, a three-dimensional fluid code (FL3P) has been developed. Using this simulator, various three-dimensional features of discharges are investigated in the sustain mode of PDP. First, the striations of wall charge are observed at both the anode and cathode side. Second, the local efficiency is obtained as a function of position. It is mainly divided into the anode region and the cathode region and highest near the anode center. Finally, the effects of various three-dimensional parameters are studied. As one of the examples showing the effect of electrode shaping, the discharge characteristics of a T-shaped electrode cell are compared with those of a conventional cell. The phosphor on barrier ribs contributes to over 44% of the total luminance, but barrier ribs themselves do not play an important role in the overall discharge efficiency. Address electrode width is not always pr...

A two-dimensional self-consistent simulation model is used to study the effect of the geometric parameters on the operating voltages and ultraviolet (UV) efficiency of a coplanar-electrode plasma display panel cell. It is found that in the standard coplanar-electrode geometry there is a tradeoff between high UV efficiency and low operating voltages as the electrode gap, or the parameters of the upper dielectric are varied, while variation of the sustain electrode width has no significant effect on either the operating voltages or UV efficiency. It is also found that wider discharge area results in higher efficiency. In addition, the effect of the insertion of floating electrodes in the upper dielectric is investigated. When floating electrodes are used, UV light is emitted in a more confined area, thus limiting cross talk with adjacent cells, while efficiency decreases by ∼8%. Finally, a self-erase discharge sustaining waveform is studied. Use of this waveform results in ∼17% increase in the UV efficiency.

A new method for visualizing data on a globe or unit sphere is described. Information that is distributed over a sphere—global oceanographic or geographic measurements, all‐sky astronomy observations, or any quantities that are best represented in spherical coordinates—can benefit from this technique. Retaining a better sense of the geometry and information content of the data, 3‐D graphics can provide an unobstructed view of the entire sphere, without undo deformation of its surface area. A ‘‘parametrized ray trace’’ produces look‐up tables (LUTs) that can be used for all visualizations. The ray trace result shows one or more spheres with the data as a texture map and three reflecting rectangles that ‘‘mirror’’ the far sides of the sphere(s) into view. The LUTs need only be created once, and a general purpose computer will do. No special purpose hardware is required beyond a PC or workstation that supports color. Examples from astronomical and geophysical datasets, which are commonly displayed with an area deforming (2‐D) projection, are presented.

An operator uses a new video display with separately adjustable magnifications along the x and y axes to assist the measuring of Fermilab 76.2‐cm bubble chamber film by our computer controlled measuring device (PEPR). The differential magnification enlarges angles and curvatures of the many fast‐forward tracks present in events of energy 100 GeV or greater. The display is used by the PEPR operator to view complicated events and guide the computer track measurement and to make manual measurements of obscured tracks which are too difficult for the automatic system to handle. We present results on 2900 events containing neutral strange particles and gamma conversions in π− p collisions at 147 GeV/c.

This paper presents a microprocessor‐controlled apparatus for the measurement of fast fluorescence waveforms. This apparatus features a dual‐time scale for the analysis of multiexponential decays. A sampling oscilloscope is used as the sampling device. The sampling time is externally controlled by means of a staircase reference voltage. The dual‐time scale is obtained by enhancing the density of sampled points in a time window corresponding to the faster portion of the waveform. The slow vertical output of the sampling oscilloscope is digitized, and numerical averaging is performed in order to improve the signal‐to‐noise ratio. An on‐line display of the measured waveform and a connection with a host computer for further data processing are also provided. Details of the hardware and software structure are given, together with applicable examples.

It has been previously reported that a liquid cystal display cell based on bistable boundary layer configurations can be switched between its bistable states by the application of dc. We report here the first experiments in the use of dc to switch an insulated cell. Included also are additional experiments with E7 in the cell of the previous report [R. B. Meyer and R. N. Thurston, Appl. Phys. Lett. 43, 342 (1983)] and a brief description of some observations with other materials. The results with the insulated cell are important because they show that the dc switching effect does not require charge transfer between the metallic electrodes and the liquid crystal.

An electromechanical scanner‐display system is described that as a scanner measures optical density in transparencies and as display device reconstructs the scanned image from digitally recorded optical density data. The instrument can accommodate image sizes up to 20×25 cm with maximum spatial resolution of 20 line pairs/mm. The optical density data are digitized into eight bits (256 levels) covering a range of 0–2.2 OD at a speed of 28 000 samples/sec. The display part of the system receives data digitized into 256 levels; out of these 95–105 can be distinguished at at output with statistical significance.

The steady state electro‐optical behavior of a dichroic type of display cell using a nematic mixture with positive dielectric anisotropy is considered. This study makes use of a mathematical simulation method. Numerical results obtained from this method are in very good agreement with experiment. The effect of physical and technological parameters of the system on the form of the transmission‐voltage characteristic is studied and in particular the slope of this characteristic in the neighborhood of the threshold voltage. The role played by the twist angle is especially considered.

We present a new, highly efficient dc electroluminescent display. A variably spaced superlattice scheme is suggested herein which can produce high‐energy injection of electrons into a ZnSe:Mn active layer in which impact excitation of the Mn centers can occur. The device is predicted to operate at an applied external bias an order of magnitude less than the best dc electroluminescent device to date. The device is predicted to have comparable brightness, since it operates in the saturation regime. The improved efficiency stems from avoiding significant energy loss to phonons. The electrons sequentially tunnel through a multilayer stack under bias and emerge into the active layer at an energy equal to the conduction‐band bending. The injection energy is chosen to coincide with the impact excitation energy of the Mn centers. Different device designs are presented and their performance is predicted.

In this paper we analyze the dynamics of a model electrowetting display (EWD) system, derive the operating parameters, and discuss the device performance. To discuss the problem we generalize the Washburn‐Yarnold treatment for the motion of a liquid slug in a capillary tube. It is shown that EWD’s have both memory and voltage threshold, and thus intrinsic matrix addressability. These properties are intimately related to the frictional surface tension forces developed between the metal and the electrolyte. Finally we present a model voltage‐driving scheme for matrix‐addressable EWD’s.

An improved display has been developed for use on our computer controlled measuring device (RIPPLE). The device features a television image of the film and a digital presentation on the same X, Y display. The television image is formed using a modified left and right raster scan which can cover 50% more area in the same time as the traditional raster.

The photographic characteristics of photoactive pigment electrographic imaging systems are investigated by analysis of two model configurations. The results establish which physical parameters control the photographic characteristics. An analysis of electrophoretic display devices is also presented. The models give estimates for the ultimate performance of these systems and make it possible to correlate photographic measurements with related physical phenomena.

A digital thickness monitor which measures the thickness of a film deposited on a quartz crystal by measuring the change of frequency of a single oscillator controlled by the resonance of the crystal is described. Conventional beat‐frequency techniques involving two precision oscillators are avoided by means of circuits including a presettable memory and an up‐down counter. The monitor is easily reset at the start of a deposition, can display either frequency change or frequency, and can be easily modified to display film thickness directly. Film thickness determined by the monitor is compared favorably to thickness values determined interferometrically.

The thermal characteristics of matrix‐addressed smectic liquid‐crystal cells are studied using the temperature dependence of the resistance of the heater and detector lines and compared to analytic solutions. The cell behavior is most strongly affected by the thermal properties of the substrate near the liquid crystal if the heater is at that interface. Cell features further away from the heater have a smaller influence. The cell power efficiency improves if the thermal flow through the substrate is reduced relative to the liquid crystal. The cell addressing speed can be increased if the substrate has two layers composed of a thin insulator on a conducting layer. Increasing the insulator thickness improves efficiency but reduces speed.

This paper describes a high resolution scanning transmission electron microscope data collection, storage, and display system. Included are a novel analog‐to‐digital converter, a digital hardware divider, a direct memory access interface to a PDP 11/20, a flicker‐free gray scale TV display, two new gray scale hardcopy devices, and a software description of the system. The system described here accepts three 8‐bit channels of image data from a single picture element every 30 μs. Each picture element intensity is measured simultaneously by three detectors. Scans of 64, 128, 256, or 512 lines of picture elements are provided. All the data are stored on one of eight disk files, and one of the three simultaneous data channels is displayed on a digitally refreshed TV screen in real time. Production of hard‐copy images and magnetic tape images, and other manipulations of the data are provided after data accumulation is terminated.

This paper describes a technique for the continuous ’’on line’’ measurement of the spatial distribution of implanted ions. The method employs a multichannel analyzer to record the digitized integrated ion current and beam position and to generate a three‐dimensional topographic display. The technique is applicable to apertured beams on mechanically rastered targets or to swept beams on stationary targets. The implant uniformity can be examined from either an isometric or a contour‐type display on the multichannel analyzer or the data can be transferred to a digital computer for more sophisticated analysis. The uniformity can be examined prior to removal of the sample from the target chamber and ’’fill in’’ techniques employed to improve the uniformity.