Contents Section 1. A Glance at Touch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 An introduction to touch technology: what it is, why and when it is used, and the reasons for touch technology’s expansion into mainstream computer applications. Why Touch Technology? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 The Benefits of Touch Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Copyright © 1998 Carroll Touch All rights reserved. No part of this book may be reproduced in any form without prior written permission from Carroll Touch. Making copies of any part of this book for any purpose other than your own personal use is a violation of United States copyright laws. For information, contact Carroll Touch, 2800 Oakmont Drive, Round Rock, Texas 78664.
Section 1. A Glance at Touch Why Touch Technology? them by the general public as well. From what started as a widespread fear of computers has now emerged widespread computer savvy - a world of employers, consumers, and students that consider computers to be a normal part of daily life and expect them to be fast and easy to use. It is this trend that has made touch technology more popular than ever.
The Benefits of Touch Technology There are many benefits to touch technology that include design advantages as well as advantages to the user. n Increased Design Opportunities Outer space or under water - the limitations of traditional input devices no longer apply when using touch technology. Touch screens fit directly onto the surface of a display or around the perimeter of it, so there is no need for concern about enough space or surface area to accommodate a peripheral device.
n Simplifies Complex Systems fused by too much information at a time. Because only valid selections are offered on the screen, the user is not confused by options that do not correspond to the task at hand. Where an extensive database is involved, touch systems simplify information by limiting the number of options or amount of data displayed at any one time. Touch targets provide step-by-step, fail-safe sequences to guide the user through a complex set of procedures.
n Graphical User Interfaces Graphical user interfaces support the use of graphics, color, and sound to capture and sustain a user’s interest. They are also intuitively easy to understand, allowing designers to create systems that can be operated easily by users with all different levels of computer experience or literacy. Graphical touch targets can be displayed on much smaller displays than what is needed to display written instructions.
Do I Need Touch Technology? n Touch technology is especially beneficial if... n Touch technology is ideally suited for creating a simple interface to an otherwise complex system. One example is an automobile diagnostics computer. This type of computer, with a traditional interface, may be frustrating to mechanics with no prior computer experience and costly to their employers during the learning curve.
Section 2. Where is Touch Being Used? Touch technology is widely used around the world. The most popular applications include point-of-sale/point of purchase, public information, medical instrumentation, mobile and hand-held systems, process control, office automation, test systems, training and simulation, industrial automation, and gaming. Point-of-Sale/Point-of Purchase Point-of-sale (POS) merchandising has been revolutionized by new technology such as automated accounting and inventory control.
Medical Instrumentation Process Control Touch input allows the integration of many functions into a single piece of equipment, thus saving valuable lab or surgery space. Plus, several touch technologies can be completely sealed, operated with gloved fingers, and are unaffected by substances that may be present on a surgical glove (such as ultrasound gel). Traditionally, the operator interface for process control systems consisted of banks of discrete controls, switches and indicators.
Computer-Based Training/Simulation Touch technology is used in everything from reading programs to flight simulators. It’s the interface of choice in such applications, because it simplifies computer use. Remember, with touch technology, you can limit the number of options or the amount of data displayed at any one time. Touch technology also allows the trainees to be given a more realistic reproduction of the operator interface they’re being trained to operate.
Industrial Automation Gaming By eliminating the keyboard in a distracting and often harsh environment, touch simplifies the human/machine interface for large, complex equipment. Interactive gaming systems designers have found that touch allows the user to concentrate on the activity presented on the screen without having to coordinate handeye movements of the input device. The intuitive nature of touch complements the selection-based activity required by interactive gaming systems.
Section 3. Types of Touch Technologies In order to select the touch technology that best fits your needs, it is important to take a brief look at how each technology functions. There are six basic types of touch technology: capacitive overlay, guided acoustic wave, resistive overlay, scanning infrared, near field imaging, and surface acoustic wave. Each type of touch technology has attributes that are desirable for specific applications.
Guided Acoustic Wave Resistive Overlay Guided acoustic wave is based on transmitting acoustic waves through a glass overlay placed over the display surface. A transducer mounted on the edge of the glass emits an acoustic wave. The wave packet travels along the reflector array, is redirected across the overlay to the reflecting edge, and returns to the array where it is reflected back to the transducer. The first reflector will send a signal back first, then the second, and so on.
Scanning Infrared Surface Acoustic Wave Scanning infrared (IR) technology relies on the interruption of an IR light grid in front of the display screen. The touch frame or opto-matrix frame contains a row of IR-light emitting diodes (LEDs) and photo transistors, each mounted on two opposite sides to create a grid of invisible infrared light. The frame assembly is comprised of printed wiring boards on which the optoelectronics are mounted and is concealed behind an IR-transparent bezel.
Near Field Imaging (NFI) NFI is based on a proprietary topology/ imaging technology. The sensor layout is a piece of glass coated with an Indium Tin Oxide (ITO) pattern on the front side and complete ITO coating on the back side. The front of the sensor is optically laminated to a layer of passive glass, typically .043” thick. An excitation waveform is supplied to the conductive sensor and generates an electrostatic field which becomes the baseline.
Section 4. Evaluating Touch Technologies Each touch input technology has both advantages and disadvantages. These advantages and disadvantages consist of physical factors associated with the technology, and with each technology’s ability to withstand the impact of factors occurring in the application’s environment. Transmissivity Another variable to consider is image clarity. The display image can be affected by placement of any material between the display image and the viewer’s eye.
Stylus Type Integration A stylus is an object or instrument used to activate a touch system, such as a finger, pen, gloved hand, etc. Integration is the process of attaching the touch system to the display. Invasive integration requires the disassembly of the display to attach the touch system. Typically, this type of integration results in voiding the manufacturer’s warranties and FCC certification. This type of integration requires a skilled technician and usually takes from 15 to 90 minutes.
Environmental Factors Dust and Dirt The ability of the touch system to withstand environmental conditions is an important factor when evaluating touch technologies. An excessive buildup of dust, dirt, or other contaminants can adversely affect the performance of some touch technologies. n Capacitive overlay, scanning infrared, and surface acoustic wave technologies will operate with low to moderate accumulations of dust, dirt, and other contaminants. Excessive levels will affect performance.
Vibration and Shock Temperature, Humidity and Altitude Vibration and shock affect each touch technology differently, ranging from no effect to severe equipment damage. This is an important consideration if the application is in an aircraft, train, ship, or other moving device. Equipment used in industrial applications can also be exposed to significant vibration or shock.
22 1024 x 1024 physical, no z-axis 21,904 points/ square inch physical, plus z-axis 256 x 256 to 4096 x 4096 physical, no z-axis 0.25” physical, 0.125” logical, no z-axis 0.030” physical, plus z-axis Near Field Imaging Guided Acoustic Wave Resistive Overlay Scanning Infrared Surface Acoustic Wave * Manufacturer’s published data.
23 NEMA 12 NEMA 4 Sensor is vulnerable to scratches and abrasions, glass overlay can be broken Not susceptible to scratching, no overlay to break, completely solidstate, no exposed parts Difficult to scratch, glass overlay is breakable Resistive Overlay Scanning Infrared Surface Acoustic Wave * Manufacturer’s published data.
Section 5. Comparison of the Touch Technologies n Sensor Drift/Calibration Capacitive overlay touch systems are subject to drift, where the touch-active zones move from the graphic targets representing them. Periodic calibration is required. Having shared an overview of the various touch technologies and the factors that can affect their suitability for use in various application environments, let us compare each technology’s advantages and disadvantages.
Guided Acoustic Wave Advantages Guided Acoustic Wave Disadvantages n Resolution - The resolution of guided acoustic wave technology is determined by how quickly the controller can interpret signals sent by the touch sensor. Typical resolution is 148 touch points per linear inch (or 21,904 points per square inch). n Stylus Requirements - Guided acoustic wave touch systems require a soft, energy absorbing stylus to operate.
Resistive Overlay Advantages Resistive Overlay Disadvantages n Resolution - Resistive overlay touch systems can deliver resolution of up to 4096 x 4096 touch points. n Transmissivity - Resistive overlay touch systems have a transmissivity of 55% to 78% due to multiple layers of different materials found in the resistive overlay sensor. They are also more susceptible to glare and reflection than any other touch technology.
Scanning Infrared Advantages Scanning Infrared Disadvantages n Transmissivity - Because there is no overlay covering the display, the transmissivity of infrared touch systems is 100%. n Resolution - Scanning infrared touch systems typically provide a resolution of eight touch points per inch. This does not usually pose a problem when using a stylus larger than 5/16” in diameter and touch targets larger than 1/2” square.
Near Field Imaging Advantages Near Field Imaging Disadvantages n Resolution - Near field imaging touch systems can deliver a resolution of up to 1024 x 1024 touch points. n Transmissivity - Near field imaging touch systems typically have a transmissivity of 85%, resulting in some degradation of image color and optical quality. n Calibration - Near field imaging systems are not subject to sensor drift. The touch system needs only to be aligned with its corresponding display.
Surface Acoustic Wave Advantages Surface Acoustic Wave Disadvantages n Resolution - The resolution of surface acoustic wave technology is determined by the physical placement of the reflector arrays. Typical resolution is 33 touch points per inch. n Stylus Requirements - Surface acoustic wave touch systems require a soft, energy-absorbing stylus to operate. A hard stylus, such as a pen, will not absorb the acoustic energy and will not be recognized as a touch.
Section 6. T o u c h P r o d u c t s D e s i g n To achieve the benefits of human factors in product design, the systems integrator must realize that the full potential and advantages of touch input require attention to many interrelated considerations. Such considerations are mechanical and physical attributes, and programming considerations. Mechanical Considerations Display Selection Selecting the computer display is one of the major decisions affecting the cost of the complete touch system.
Space Constraints Sealing Many touch systems will be located in areas where space is limited. Flat panels require very little space, while CRTs tend to be bulky. The amount of physical space required for the touch system varies for the different touch technologies. The type of integration selected can also affect the amount of space required to hold the system. Invasive integrations tend to use less space than noninvasive integrations.
Physical Attributes Most touch systems provide features such as multiple operating and reporting modes, improved software resolution, fault tolerance and diagnostics. The number and type of features required by a technology depend on the amount of control needed by the designer’s application.
Section 7. Programming Considerations Of prime consideration to the applications programmer is the interaction or communication between system hardware units, the system software packages, and the vital interface between the touch application and the user. Touch vendors have proprietary software interface protocols unique to their touch systems. All of the touch vendors’ software protocols report an x and y coordinate; some technologies permit the reporting of a z coordinate as well.
Authoring System Graphical User Interfaces An authoring system is a program that the application developer can use to create a touch application without writing programming code. Authoring systems either include direct support for the touch system, or run under a graphical user interface (GUI), which provides support for the touch system. HypercardTM for the Macintosh and Asymetrix ToolbookTM for the IBM PCTM are examples of such authoring systems.
n Touch User Interface The application program is the interface between the user and the computer system. The application program presents displays, accepts user input, and takes action based on that input. The design and organization of the program is critical to the successful use of the touch system, especially when the end users are likely to be novices. The number of targets per screen should be limited to as few as possible, balanced by the difficulty of switching screens.
Touch Activation Modes Touch Feedback Activation mode refers to the behavior of the target when it is touched. Slides, switches and buttons are typical variations of touch targets. A typical button target has three states: unarmed, armed, and activated. Feedback is an integral part of most well designed activation modes. The user must receive immediate feedback to know for certain when a target has been armed and/or activated.
Section 8. Glossary - The process of setting the spatial relationship of the display’s coordinate system to the touch coordinate system. This facilitates the translation of touch coordinates into display video coordinates. component or a system is expected to perform before a failure occurs. Alignment - National Equipment Manufacturers Association. NEMA 4 compliance indicates that a device can withstand hose-directed water and still operate.
- A finger, digital pen, or any device used to activate the touch system. Stylus - The positions on the x-axis and the y-axis where a touch is detected. Touch Coordinates Touch Event - A response that is programmed to occur when a touch target is touched, such as activating a new display screen or menu. In GUI applications, touch events are usually mapped to mouse button click events.
For More Information, Call Toll-Free (800) 386-8241 Modular Flat Panel Mounting and Environments Guide - This guide offers an overview of the integration of our modular touch systems with flat panel displays. Issues such as mounting, sealing and coating techniques, as well as environmental factors are discussed. For more information about touch technology and Carroll Touch products, refer to the list of Carroll Touch publications on this page.
