Monday, January 28, 2008

Touch Screen Technology...complete information


Touchscreens, touch screens, touch panels or touchscreen panels are display overlays which have the ability to display and receive information on the same screen. The effect of such overlays allows a display to be used as an input device, removing the keyboard and/or the mouse as the primary input device for interacting with the display's content. Such displays can be attached to computers or, as terminals, to networks.

Touch Screen Technology

1. There are a number of types of touch screen technology:


A resistive touch screen panel is coated with a thin metallic electrically conductive and resistive layer that causes a change in the electrical current which is registered as a touch event and sent to the controller for processing.

Some resistive panels can estimate the area (and hence the pressure) of a touch based on calculations from the resistances.

Resistive touch screen panels are generally more affordable but offer only 75% clarity (premium films and glass finishes allow transmissivity to approach 85% and the layer can be damaged by sharp objects. Resistive touch screen panels are not affected by outside elements such as dust or water and are the type most commonly used today.

Surface Acoustic Wave (SAW)

Surface Acoustic Wave technology uses ultrasonic waves that pass over the touch screen panel. When the panel is touched, a portion of the wave is absorbed. This change in the ultrasonic waves registers the position of the touch event and sends this information to the controller for processing. Surface wave touch screen panels can be damaged by outside elements. Contaminants on the surface can also interfere with the functionality of the touchscreen.


A capacitive touch screen panel is coated with a material, typically indium tin oxide that conducts a continuous electrical current across the sensor. The sensor therefore exhibits a precisely controlled field of stored electrons in both the horizontal and vertical axes - it achieves capacitance. The human body is also an electrical device which has stored electrons and therefore also exhibits capacitance. When the sensor's 'normal' capacitance field (its reference state) is altered by another capacitance field, i.e., someone's finger, electronic circuits located at each corner of the panel measure the resultant 'distortion' in the sine wave characteristics of the reference field and send the information about the event to the controller for mathematical processing. Capacitive sensors can either be touched with a bare finger or with a conductive device being held by a bare hand. Capacitive touch screens are not affected by outside elements and have high clarity, but their complex signal processing electronics increase their cost.


An infrared touch screen panel employs one of two very different methodologies. One method used thermal induced changes of the surface resistance. This method was sometimes slow and required warm hands. Another method is an array of vertical and horizontal IR sensors that detected the interruption of a modulated light beam near the surface of the screen.IR touch screens have the most durable surfaces and are used in many military applications that require a touch panel display.

Optical Imaging

A relatively-modern development in touch screen technology, two or more image sensors are placed around the edges (usually the corners) of the screen. Infrared backlights are placed in the camera's field of view on the other sides of the screen. A touch shows up as a shadow and each pair of cameras can then be triangulated to locate the touch. This technology is growing in popularity, due to its scalability, versatility,and affordability, especially for larger units.

Dispersive Signal Technology

Introduced in 2002, this system uses sensors to detect the mechanical energy in the glass that occur due to a touch. Complex algorithms then interpret this information and provide the actual location of the touch. The technology claims to be unaffected by dust and other outside elements, including scratches. Since there is no need for additional elements on screen, it also claims to provide excellent optical clarity. Also, since mechanical vibrations are used to detect a touch event, any object can be used to generate these events, including fingers and styli.

Acoustic Pulse Recognition

This system uses more than two piezoelectric transducers located at some positions of the screen to turn the mechanical energy of a touch (vibration) into an electronic signal.This signal is then converted into an audio file, and then compared to preexisting audio profile for every position on the screen. This system works without a grid of wires running through the screen, the touch screen itself is actually pure glass, giving it the optics and durability of the glass out of which it is made. It works with scratches and dust on the screen, and accuracy is very good. It does not need a conductive object to activate it. It is a major advantage for larger displays

2. Touchscreens also have assisted in recent changes in the PDA and Cell-Phone Industries, making these devices more usable.

ViP Interactive Interactive overlay for LCD’s and rear projection screens

If you are looking to take advantage of the expanding market for through window and internal interactive touch screen solutions, Then the ViP Interactive foil has been designed for you. By applying our

touch-screen technology onto glass or acrylic, you can create an ideal platform for applying rear projection screens or mounting in front of LCD screens. With this product you can now sell into a whole new market sector and generate new revenue streams for your business

Product features

  • No requirement to have any external wires or devices as all of the touch screen components are situated safely behind the glass
  • Wide range of custom screen sizes available Sizes up to 100 inch 16:9 format
  • Interactivity works even with a gloved hand

Permanent and removable fixing system available

Interactivity specification

Detection Method:

Projected Capacitance technology using horizontal vertical wires

Screen Sizes:

40”- 80” 4:3 40”-100”16:9 as standard, other sizes available on request

Fixing Options:

Removable and permanent options available

Position accuracy:

Approximately 3 mm absolute, 1 mm relative. No drift


Software drivers provide a calibration facility


Can be programmed for different thickness of glass and even use with gloved hands. Standard configuration functions with non-metallised. single construction glass 16mm thick. Double glazing option up to 25mm available*

Speed of response:

Depends upon glass thickness. Typically 50 to 100ms


RS232C communications to a 9 pin D female

Software Compatibility:

Drivers are available for Windows Operating Systems

Temperature range:

Better than -10 to +70°C

Humidity Controller:

0% to 95%. Unaffected by condensation

Light Transmission:

Depend upon glass thickness, typically better than 93%

Stick it and touch it
Interactive foil for through-window touch applications

Our lightweight touch foil can be applied directly to a window or a glass sheet and then a rear projection screen or LCD can be mounted behind the touch foil to create a through-window/glass touch experience.
The ViP Interactive foil can be mounted using either a permanent or a removable fixing method allowing the touch unit to be moved to another location if required.
The touch foil is ideal for upgrading existing through window rear projection or LCD displays to create a through window touch experience.
There are no external components required with the ViP Interactive foil so the installation is completely safe behind the window.

Product features

  • Lightweight foil simple to apply to a window, glass, acrylic and rear projection screens and any other non-metallic material.
  • No requirement to have any external wires or devices as all of the touch screen components are situated safely behind the glass.
  • Interactivity works even with gloved hand.
  • Not affected by external light conditions
  • Wide range of screen sizes available up to 80 inch 4:3 or 100 inch 16:9 format
  • Works with all existing multimedia applications PowerPoint, Macromedia flash, Web sites etc.
  • Simple set-up

Holographic Screens

If you are looking for a large (up to 100" 2.54m diagonal) high quality display that will provide stunning images even in high ambient light conditions such as a shop window, then a holographic screen is your answer. Holographic screens come in two different formats: - Translucent glass construction that can be used as a window display or as a stand-alone presentation unit and translucent foils that can be directly attached to a shop window, effectively turning the window into a display device.

These screens are ideal for shop windows, car dealerships, travel agencies, museums, banks, airports, railway stations and any public place where high impact, high quality images are required.


Touch screen technology has been around for a number of years. In the past POS applications built around Touch screen technology have been limited to hospitality terminals and as the preferred interface on retail kiosk terminals.

Use of touch screen technology on point of sale terminals has proven to be a valuable and cost effective tool in the hospitality industry reducing transaction times, operator errors and training time in an industry with a very high employee turnover rate. Until now the cost of touch screen monitors has prevented this technology from being adopted for use by chain retailers in non hospitality retail segments. This technology is no longer cost prohibitive allowing Retailers in segments to take advantage of the benefits of Touch screen technology.Justifying the Cost of Touch Screen Technology, In the past two years the cost of touch screen monitors has dropped dramatically. These cost reductions have now made it possible for retail chains to take advantage of touch screen technology in conventional retail point of sale applications.

Hardware Cost :

A touch screen monitor replaces the VGA monitor and eliminates the need for a costly

proprietary big-ticket POS keyboard. Today most retailers incorporate debit card support into their POS applications. Pin terminals with magnetic stripe readers have eliminated the need for a MSR included in the POS keyboard or as standalone device. Many POS touch screen applications, including SDI’s new IRIS Touch/POS application, incorporate a large customer price display area on the touch screen eliminating the need for a separate customer display.

The elimination of these costly proprietary POS peripherals and their related maintenance costs typically will offset the extra cost of a touch screen monitor.

Touch screen monitors are here to stay. POS applications designed around MS Windows that support this touch screen and new modern OPOS peripheral interfaces will operate on any industry standard PC hardware and can be ported from one platform to another with change to application software.

Soft Benefits of Touch Screen Technology :

Retail chains are experiencing ever increasing employee turnover rates. The cost of training cashiers and other retail employees continues to escalate and is a major concern to retailers.This is especially true in retail environments that must cater to complex transactions or interact with frequent shopper or other customer database information. As has been demonstrated, lookup facilities significantly reduce new employee training time and efficiency. The intuitive nature of a touch screen application makes it easier for cashiers to learn and increases the overall productivity of both inexperienced and experienced cashiers. A higher level of employee competence means reduced errors, higher throughput and bettercustomer service.These benefits translate into lower training costs, increased employee productivity and an increase in customer shopping satisfaction.

Application Flexibility :

Eliminating the inherent limitations related to development of POS applications that are dependant of\n function keys of a keyboard or custom device interfaces allows the POS application to be more flexible and more intuitive. The use of dynamic touch buttons eliminates the problem of developing around limited function keys and increases the POS developer’s flexibility. This translates into reduced development time and applications that are easier for cashiers to understand.

Applications built around proprietary peripherals like expanded POS keyboards cannot be changed or ported from one platform to another without change unless that platform supports the same proprietary peripherals. Supporting proprietary peripherals increases the application maintenance costs and as technology changes many proprietary peripherals become obsolete or unavailable. These costs are minimized with the use of touch screen technology.

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