27-11-2010, 11:26 AM
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Presented By: PATEL JAYENDRA K
History of touchscreen?
A special thanks goes to Jason Ford of Elo TouchSystems, the company whose founder invented touch screen technology, for providing the following historical information.
In 1971, the first "touch sensor" was developed by Doctor Sam Hurst (founder of Elographics) while he was an instructor at the University of Kentucky. This sensor called the "Elograph" was patented by The University of Kentucky Research Foundation. The "Elograph" was not transparent like modern touch screens, however, it was a significant milestone in touch screen technology.
In 1974, the first true touch screen incorporating a transparent surface came on the scene developed by Sam Hurst and Elographics. In 1977, Elographics developed and patented five-wire resistive technology, the most popular touch screen technology in use today. On February 24, 1994, the company officially changed its name from Elographics to Elo TouchSystems.
What is Touch screen?
A touch screen is a computer display screen that is sensitive to human touch, allowing a user to interact with the computer by touching pictures or words on the screen.
A type of display screen that has a touch-sensitive transparent panel covering the screen. Instead of using a pointing device such as a mouse or light pen, you can use your finger to point directly to objects on the screen.
Touch screens are used with information kiosks, computer-based training devices, and systems designed to help individuals who have difficulty manipulating a mouse or keyboard.
Touch screen technology can be used as an alternative user interface with applications that normally require a mouse, such as a Web browser. Some applications are designed specifically for touch screen technology, often having larger icons and links than the typical PC application.
Monitors are available with built-in touch screen technology or individuals can purchase a touch screen kit. A touch screen kit includes a touch screen panel, a controller, and a software driver.
The touch screen panel is a clear panel attached externally to the monitor that plugs into a serial or Universal Serial Bus (USB) port or a bus card installed inside the computer. The touch screen panel registers touch events and passes these signals to the controller. The controller then processes the signals and sends the data to the processor.
The software driver translates touch events into mouse events. Drivers can be provided for both Windows and Macintosh operating systems.
Internal touch screen kits are available but require professional installation because they must be installed inside the monitor.Although touch screens provide a natural interface for computer novices, they are unsatisfactory for most applications because the finger is such a relatively large object.
It is impossible to point accurately to small areas of the screen. In addition, most users find touch screens tiring to the arms after long use.
How Does a Touchscreen Work?
A basic touchscreen has three main components: a touch sensor, a controller, and a software driver. The touchscreen is an input device, so it needs to be combined with a display and a PC or other device to make a complete touch input system
1. Touch Sensor
A touch screen sensor is a clear glass panel with a touch responsive surface. The touch sensor/panel is placed over a display screen so that the responsive area of the panel covers the viewable area of the video screen. There are several different touch sensor technologies on the market today, each using a different method to detect touch input. The sensor generally has an electrical current or signal going through it and touching the screen causes a voltage or signal change. This voltage change is used to determine the location of the touch to the screen.
2. Controller
The controller is a small PC card that connects between the touch sensor and the PC. It takes information from the touch sensor and translates it into information that PC can understand. The controller is usually installed inside the monitor for integrated monitors or it is housed in a plastic case for external touch add-ons/overlays. The controller determines what type of interface/connection you will need on the PC. Integrated touch monitors will have an extra cable connection on the back for the touchscreen. Controllers are available that can connect to a Serial/COM port (PC) or to a USB port (PC or Macintosh). Specialized controllers are also available that work with DVD players and other devices.
3. Software Driver
The driver is a software update for the PC system that allows the touchscreen and computer to work together. It tells the computer's operating system how to interpret the touch event information that is sent from the controller. Most touch screen drivers today are a mouse-emulation type driver. This makes touching the screen the same as clicking your mouse at the same location on the screen. This allows the touchscreen to work with existing software and allows new applications to be developed without the need for touchscreen specific programming. Some equipment such as thin client terminals, DVD players, and specialized computer systems either do not use software drivers or they have their own built-in touch screen driver.
Touch screen monitors — where you can use your finger on the computer screen to navigate through the contents — have become more and more commonplace over the past decade, particularly at public information kiosks. A basic touch screen has three main components: a touch sensor, a controller, and a software driver. The touch screen is an input device, so it needs to be combined with a display and a PC to make a complete touch input system.
The Touch Sensor has a textured coating across the glass face. This coating is sensitive to pressure and registers the location of the user's finger when it touches the screen. The controller is a small PC card that connects the touch sensor to the PC. It takes information from the touch sensor and translates it into information that PC can understand. The Software Driver is a software update for the PC system that allows the touchscreen and computer to work together. It tells the computer's operating system how to interpret the touch event information that is sent from the controller.
There are three basic systems that are used to recognise a person's touch — Resistive, Capacitive and Surface acoustic wave.
The resistive system consists of a normal glass panel that is covered with a conductive and a resistive metallic layer. These layers are held apart by spacers, and a scratch-resistant layer is placed on top of the whole set up. An electrical current runs through the two layers while the monitor is operational. When a user touches the screen, the two layers make contact in that spot. The change in electrical field is noted and coordinates of the point of contact are calculated. Once the coordinates are known, a special driver translates the touch into something that the operating system can understand, much as a computer mouse driver translates a mouse's movements into a click or drag.
In the capacitive system, a layer that stores electrical charge is placed on the glass panel of the monitor. When a user touches the monitor with his or her finger, some of the charge is transferred to the user, so the charge on the capacitive layer decreases. This decrease is measured in circuits located at each corner of the monitor. The computer calculates, from the relative differences in charge at each corner, exactly where the touch event took place and then relays that information to the touch screen driver software. One advantage of the capacitive system is that it transmits almost 90 per cent of the light from the monitor, whereas the resistive system only transmits about 75 per cent. This gives the capacitive system a much clearer picture than the resistive system.
The surface acoustic wave system uses two transducers (one receiving and one sending) placed along the x and y axes of the monitor's glass plate. Also placed on the glass are reflectors — they reflect an electrical signal sent from one transducer to the other. The receiving transducer is able to tell if the wave has been disturbed by a touch event at any instant, and can locate it accordingly. The wave setup has no metallic layers on the screen, allowing for 100-percent light throughput and perfect image clarity. This makes the surface acoustic wave system best for displaying detailed graphics (both other systems have significant degradation in clarity).
Another area in which the systems differ is which stimuli will register as a touch event. A resistive system registers a touch as long as the two layers make contact, which means that it doesn't matter if you touch it with your finger or a rubber ball. A capacitive system, on the other hand, must have a conductive input, usually your finger, in order to register a touch. The surface acoustic wave system works much like the resistive system, allowing a touch with almost any object — except hard and small objects like a pen tip.
Technologies
There are a number of types of touch screen technology
1. Resistive
A resistive touch screen panel is composed of several layers. The most important are two thin metallic electrically conductive and resistive layers separated by thin space. When some object touches this kind of touch panel, the layers are connected at certain point; the panel then electrically acts similar to two voltage dividers with connected outputs. This causes a change in the electrical current which is registered as a touch event and sent to the controller for processing. When measuring press force, it is useful to add resistor dependent on force in this model -- between the dividers.
A resistive touch panel output can consist of between four and eight wires. The positions of the conductive contacts in resistive layers differ depending on how many wires are used.
When four wires are used, the contacts are placed on the left, right, top, and bottom sides.
When five wires are used, the contacts are placed in the corners and on one plate.
4 wire 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.
5-wire resistive touch screens are very accurate and reliable. Everyone can use them for whatever purpose he or she wants.
Our touch screens enlarge the active area to the entire screen, and advance an excellent quality as compared to common displays because of improved flatness and durability of the touché+d surface
8-Wire Resistive Technology
Resistive touchscreen technology exists in 4-wire, 5-wire, or 8-wire forms. FastPoint LCD touchscreens specifically employ 8-wire resistive technology because of its benefits over its counterparts. Whereas 8-wire FastPoint touchscreens are available in all sizes, 4-wire resistive technology is restricted to small flatpanels (<10.4"). Additionally, 8-wire resistive touchscreens are not susceptible to problems caused by high-level short-term variances and axis linearity and drift.
1.Polyester Flim
2.Uper Resistive circuit Layer
3.condutive ITO(Transparent metal)
4. Lower Resitive Circuit Layer
5.Insulating Dots
6.Glass/Acrlic Substrate
7.Touching the overlay surface causes the (2) Upper Resistive circuit Layer to contact the (4) Lower Resistive circuit Layer ,producing a circuit switch from the activated area.
8.The touchscreen controller gets the alternating voltages between the (7) two circuit Layer and converts them into the digital X and Y coordinates of the activated area.
2. Surface acoustic wave
Surface Acoustic Wave (SAW) 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.
3.Capacitive
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.
A capacitive touch screen consists of a glass panel with a capacitive (charge storing) material coating its surface. Circuits located at corners of the screen measure the capacitance of a person touching the overlay. Frequency changes are measured to determine the X and Y coordinates of the touch event.
Capacitive type touch screens are very durable, and have a high clarity. They are used in a wide range of applications, from restaurant and POS use to industrial controls and information kiosks.
Advantages
High touch resolution
High image clarity
Not affected by dirt, grease, moisture.
Disadvantages
Must be touched by finger, will not work with any non-conductive input
4.Infrared
An infrared touch screen panel employs one of two very different methods. 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.
5. Strain gauge
In a strain gauge configuration the screen is spring mounted on the four corners and strain gauges are used to determine deflection when the screen is touched. This technology can also measure the Z-axis. Typically used in exposed public systems such as ticket machines due to their resistance to vandalism.
6.Optical imaging
A relatively-modern development in touch screen technology, two or more image sensors are placed around the edges (mostly 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.
7. 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. A downside is that after the initial touch the system cannot detect a motionless finger.
8.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. As with the Dispersive Signal Technology system, after the initial touch this system cannot detect a motionless finger.
9. Frustrated total internal reflection
This optical system works by using the principle of total internal reflection to fill a refractive medium with light. When a finger or other soft object is pressed against the surface, the internal reflection light path is interrupted, making the light reflect outside of the medium and thus visible to a camera behind the medium.
10. IntelliTouch surface wave
IntelliTouch surface wave is the optical standard of touch. Its pure glass construction provides superior optical performance and makes it the most scratch-resistant technology available. It's nearly impossible to physically "wear out" this touchscreen. IntelliTouch is widely used in kiosk, gaming, and office automation applications and is available for both flat panel and CRT solutions.
Benefits
• Surface wave (also known as surface acoustic wave, or SAW) technology
• Pure-glass touchscreens for superior image clarity, resolution, and light transmission
• Durable, scratch-resistant glass surface—continues to work if scratched
• Stable "drift-free" operation—for touch response that's always accurate
• Finger, gloved hand, and soft stylus activation
• Fast touch response
• Sensitive touch response—recognizes location and amount of pressure applied
11. SecureTouch Surface Wave Touchscreens
Flat-screen SecureTouch products are made of extra-tough glass substrates that resist vandalism. These touchscreens incorporate the solid-glass and coating-free construction of Elo's proven IntelliTouch products.
How to connect touchscreen on your own computer?
The Add-On Kit can be easily mounted on ANY monitor / Laptops/POS systems and used for ANY mouse driven application.
It also help childrens to start learning how to use computer without the difficulty of using the mouse.
Easily mounts on ANY standard computer monitor with simple attachments.
Touchscreens Add-ons and Integrated Touchscreen Monitors
There is main two types of touchscreen products, touchscreen add-ons and integrated touchscreen monitors. Touchscreen add-ons are touchscreen panels that hang over an existing computer monitor. Integrated touchscreen monitors are computer displays that have the touchscreen built-in. Both product types work in the same way, basically as an input device like a mouse or trackpad.
Touchscreens As Input Device
All of the touchscreens that basically work like a mouse. Once the software driver for the touchscreen is installed, the touchscreen emulates mouse functions. Touching the screen is basically the same as clicking your mouse at the same point at the screen. When you touch the touchscreen, the mouse cursor will move to that point and make a mouse click. You can tap the screen twice to perform a double-click, and you can also drag your finger across the touchscreen to perform drag-and-drops. The touchscreens will normally emulate left mouse clicks. Through software, you can also switch the touchscreen to perform right mouse clicks instead.
Development in Touchscreen
Virtually all of the significant touchscreen technology patents were filed during the 1970s and 1980s and have expired. Touchscreen component manufacturing and product design are no longer encumbered by royalties or legalities with regard to patents and the manufacturing of touchscreen-enabled displays on all kinds of devices is widespread.
The development of multipoint touchscreens facilitated the tracking of more than one finger on the screen, thus operations that require more than one finger are possible. These devices also allow multiple users to interact with the touchscreen simultaneously.
With the growing acceptance of many kinds of products with an integral touchscreen interface the marginal cost of touchscreen technology is routinely absorbed into the products that incorporate it and is effectively eliminated. As typically occurs with any technology, touchscreen hardware and software has sufficiently matured and been perfected over more than three decades to the point where its reliability is unassailable. As such, touchscreen displays are found today in airplanes, automobiles, gaming consoles, machine control systems, appliances and handheld display devices of every kind.
The ability to accurately point on the screen itself is taking yet another step with the emerging graphics tablet/screen hybrids.
Ergonomics and usage
An ergonomic problem of touchscreens is their stress on human fingers when used for more than a few minutes at a time, since significant pressure can be required and the screen is non-flexible. This can be alleviated with the use of a pen or other device to add leverage, but the introduction of such items can sometimes be problematic depending on the desired use case (for example, public kiosks such as ATMs). Also, fine motor control is better achieved with a stylus, a finger being a rather broad and ambiguous point of contact with the screen.
Yet all of these ergonomic issues can be bypassed simply by using a different technique, provided that the user's fingernails are either short or sufficiently long. Rather than pressing with the soft skin of an outstretched fingertip, the finger is curled over, so that the top of the forward edge of a fingernail can be used instead. (The thumb is optionally used to provide support for the finger or for a long fingernail, from underneath.) The fingernail's hard, curved surface contacts the touchscreen at a single very small point. Therefore, much less finger pressure is needed, much greater precision is possible (approaching that of a stylus, with a little experience), much less skin oil is smeared onto the screen, and the fingernail can be silently moved across the screen with very little resistance, allowing for selecting text, moving windows, or drawing lines. (The human fingernail consists of keratin which has a hardness and smoothness similar to the tip of a stylus, and so will not typically scratch a touchscreen.) Alternately, very short stylus tips are available, which slip right onto the end of a finger; this increases visibility of the contact point with the screen. Oddly, with capacitive touch screens, the reverse problem applies in that individuals with long nails have reported problems getting adequate skin contact with the screen to register keystrokes (note that styluses do not work on capacitive touch screens nor do gloved fingers).
Future Of Multi-Input Touch Screen
We might heard of touch screen and often use in atm’s,mobile etc but that a standard touch screen allows one input at a time.Can you imagine what if this allows multiple people to use it and allows for Minority Report like features.This sort of screens are are recently demonstrate by Jefferson .Y.Han.Its really awesome have a look on this video
The display of these screen are really super cool as we use now a day’s on TFT display.
Whenever it launches on market, i wish to get one through Loyalty Cards,Well this experiments of multi-input touch screen is revolutionary in the market as it can create many platform for various instruments that needs multi-manpower.
Presented By: PATEL JAYENDRA K
touch screen technology
History of touchscreen?
A special thanks goes to Jason Ford of Elo TouchSystems, the company whose founder invented touch screen technology, for providing the following historical information.
In 1971, the first "touch sensor" was developed by Doctor Sam Hurst (founder of Elographics) while he was an instructor at the University of Kentucky. This sensor called the "Elograph" was patented by The University of Kentucky Research Foundation. The "Elograph" was not transparent like modern touch screens, however, it was a significant milestone in touch screen technology.
In 1974, the first true touch screen incorporating a transparent surface came on the scene developed by Sam Hurst and Elographics. In 1977, Elographics developed and patented five-wire resistive technology, the most popular touch screen technology in use today. On February 24, 1994, the company officially changed its name from Elographics to Elo TouchSystems.
What is Touch screen?
A touch screen is a computer display screen that is sensitive to human touch, allowing a user to interact with the computer by touching pictures or words on the screen.
A type of display screen that has a touch-sensitive transparent panel covering the screen. Instead of using a pointing device such as a mouse or light pen, you can use your finger to point directly to objects on the screen.
Touch screens are used with information kiosks, computer-based training devices, and systems designed to help individuals who have difficulty manipulating a mouse or keyboard.
Touch screen technology can be used as an alternative user interface with applications that normally require a mouse, such as a Web browser. Some applications are designed specifically for touch screen technology, often having larger icons and links than the typical PC application.
Monitors are available with built-in touch screen technology or individuals can purchase a touch screen kit. A touch screen kit includes a touch screen panel, a controller, and a software driver.
The touch screen panel is a clear panel attached externally to the monitor that plugs into a serial or Universal Serial Bus (USB) port or a bus card installed inside the computer. The touch screen panel registers touch events and passes these signals to the controller. The controller then processes the signals and sends the data to the processor.
The software driver translates touch events into mouse events. Drivers can be provided for both Windows and Macintosh operating systems.
Internal touch screen kits are available but require professional installation because they must be installed inside the monitor.Although touch screens provide a natural interface for computer novices, they are unsatisfactory for most applications because the finger is such a relatively large object.
It is impossible to point accurately to small areas of the screen. In addition, most users find touch screens tiring to the arms after long use.
How Does a Touchscreen Work?
A basic touchscreen has three main components: a touch sensor, a controller, and a software driver. The touchscreen is an input device, so it needs to be combined with a display and a PC or other device to make a complete touch input system
1. Touch Sensor
A touch screen sensor is a clear glass panel with a touch responsive surface. The touch sensor/panel is placed over a display screen so that the responsive area of the panel covers the viewable area of the video screen. There are several different touch sensor technologies on the market today, each using a different method to detect touch input. The sensor generally has an electrical current or signal going through it and touching the screen causes a voltage or signal change. This voltage change is used to determine the location of the touch to the screen.
2. Controller
The controller is a small PC card that connects between the touch sensor and the PC. It takes information from the touch sensor and translates it into information that PC can understand. The controller is usually installed inside the monitor for integrated monitors or it is housed in a plastic case for external touch add-ons/overlays. The controller determines what type of interface/connection you will need on the PC. Integrated touch monitors will have an extra cable connection on the back for the touchscreen. Controllers are available that can connect to a Serial/COM port (PC) or to a USB port (PC or Macintosh). Specialized controllers are also available that work with DVD players and other devices.
3. Software Driver
The driver is a software update for the PC system that allows the touchscreen and computer to work together. It tells the computer's operating system how to interpret the touch event information that is sent from the controller. Most touch screen drivers today are a mouse-emulation type driver. This makes touching the screen the same as clicking your mouse at the same location on the screen. This allows the touchscreen to work with existing software and allows new applications to be developed without the need for touchscreen specific programming. Some equipment such as thin client terminals, DVD players, and specialized computer systems either do not use software drivers or they have their own built-in touch screen driver.
Touch screen monitors — where you can use your finger on the computer screen to navigate through the contents — have become more and more commonplace over the past decade, particularly at public information kiosks. A basic touch screen has three main components: a touch sensor, a controller, and a software driver. The touch screen is an input device, so it needs to be combined with a display and a PC to make a complete touch input system.
The Touch Sensor has a textured coating across the glass face. This coating is sensitive to pressure and registers the location of the user's finger when it touches the screen. The controller is a small PC card that connects the touch sensor to the PC. It takes information from the touch sensor and translates it into information that PC can understand. The Software Driver is a software update for the PC system that allows the touchscreen and computer to work together. It tells the computer's operating system how to interpret the touch event information that is sent from the controller.
There are three basic systems that are used to recognise a person's touch — Resistive, Capacitive and Surface acoustic wave.
The resistive system consists of a normal glass panel that is covered with a conductive and a resistive metallic layer. These layers are held apart by spacers, and a scratch-resistant layer is placed on top of the whole set up. An electrical current runs through the two layers while the monitor is operational. When a user touches the screen, the two layers make contact in that spot. The change in electrical field is noted and coordinates of the point of contact are calculated. Once the coordinates are known, a special driver translates the touch into something that the operating system can understand, much as a computer mouse driver translates a mouse's movements into a click or drag.
In the capacitive system, a layer that stores electrical charge is placed on the glass panel of the monitor. When a user touches the monitor with his or her finger, some of the charge is transferred to the user, so the charge on the capacitive layer decreases. This decrease is measured in circuits located at each corner of the monitor. The computer calculates, from the relative differences in charge at each corner, exactly where the touch event took place and then relays that information to the touch screen driver software. One advantage of the capacitive system is that it transmits almost 90 per cent of the light from the monitor, whereas the resistive system only transmits about 75 per cent. This gives the capacitive system a much clearer picture than the resistive system.
The surface acoustic wave system uses two transducers (one receiving and one sending) placed along the x and y axes of the monitor's glass plate. Also placed on the glass are reflectors — they reflect an electrical signal sent from one transducer to the other. The receiving transducer is able to tell if the wave has been disturbed by a touch event at any instant, and can locate it accordingly. The wave setup has no metallic layers on the screen, allowing for 100-percent light throughput and perfect image clarity. This makes the surface acoustic wave system best for displaying detailed graphics (both other systems have significant degradation in clarity).
Another area in which the systems differ is which stimuli will register as a touch event. A resistive system registers a touch as long as the two layers make contact, which means that it doesn't matter if you touch it with your finger or a rubber ball. A capacitive system, on the other hand, must have a conductive input, usually your finger, in order to register a touch. The surface acoustic wave system works much like the resistive system, allowing a touch with almost any object — except hard and small objects like a pen tip.
Technologies
There are a number of types of touch screen technology
1. Resistive
A resistive touch screen panel is composed of several layers. The most important are two thin metallic electrically conductive and resistive layers separated by thin space. When some object touches this kind of touch panel, the layers are connected at certain point; the panel then electrically acts similar to two voltage dividers with connected outputs. This causes a change in the electrical current which is registered as a touch event and sent to the controller for processing. When measuring press force, it is useful to add resistor dependent on force in this model -- between the dividers.
A resistive touch panel output can consist of between four and eight wires. The positions of the conductive contacts in resistive layers differ depending on how many wires are used.
When four wires are used, the contacts are placed on the left, right, top, and bottom sides.
When five wires are used, the contacts are placed in the corners and on one plate.
4 wire 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.
5-wire resistive touch screens are very accurate and reliable. Everyone can use them for whatever purpose he or she wants.
Our touch screens enlarge the active area to the entire screen, and advance an excellent quality as compared to common displays because of improved flatness and durability of the touché+d surface
8-Wire Resistive Technology
Resistive touchscreen technology exists in 4-wire, 5-wire, or 8-wire forms. FastPoint LCD touchscreens specifically employ 8-wire resistive technology because of its benefits over its counterparts. Whereas 8-wire FastPoint touchscreens are available in all sizes, 4-wire resistive technology is restricted to small flatpanels (<10.4"). Additionally, 8-wire resistive touchscreens are not susceptible to problems caused by high-level short-term variances and axis linearity and drift.
1.Polyester Flim
2.Uper Resistive circuit Layer
3.condutive ITO(Transparent metal)
4. Lower Resitive Circuit Layer
5.Insulating Dots
6.Glass/Acrlic Substrate
7.Touching the overlay surface causes the (2) Upper Resistive circuit Layer to contact the (4) Lower Resistive circuit Layer ,producing a circuit switch from the activated area.
8.The touchscreen controller gets the alternating voltages between the (7) two circuit Layer and converts them into the digital X and Y coordinates of the activated area.
2. Surface acoustic wave
Surface Acoustic Wave (SAW) 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.
3.Capacitive
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.
A capacitive touch screen consists of a glass panel with a capacitive (charge storing) material coating its surface. Circuits located at corners of the screen measure the capacitance of a person touching the overlay. Frequency changes are measured to determine the X and Y coordinates of the touch event.
Capacitive type touch screens are very durable, and have a high clarity. They are used in a wide range of applications, from restaurant and POS use to industrial controls and information kiosks.
Advantages
High touch resolution
High image clarity
Not affected by dirt, grease, moisture.
Disadvantages
Must be touched by finger, will not work with any non-conductive input
4.Infrared
An infrared touch screen panel employs one of two very different methods. 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.
5. Strain gauge
In a strain gauge configuration the screen is spring mounted on the four corners and strain gauges are used to determine deflection when the screen is touched. This technology can also measure the Z-axis. Typically used in exposed public systems such as ticket machines due to their resistance to vandalism.
6.Optical imaging
A relatively-modern development in touch screen technology, two or more image sensors are placed around the edges (mostly 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.
7. 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. A downside is that after the initial touch the system cannot detect a motionless finger.
8.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. As with the Dispersive Signal Technology system, after the initial touch this system cannot detect a motionless finger.
9. Frustrated total internal reflection
This optical system works by using the principle of total internal reflection to fill a refractive medium with light. When a finger or other soft object is pressed against the surface, the internal reflection light path is interrupted, making the light reflect outside of the medium and thus visible to a camera behind the medium.
10. IntelliTouch surface wave
IntelliTouch surface wave is the optical standard of touch. Its pure glass construction provides superior optical performance and makes it the most scratch-resistant technology available. It's nearly impossible to physically "wear out" this touchscreen. IntelliTouch is widely used in kiosk, gaming, and office automation applications and is available for both flat panel and CRT solutions.
Benefits
• Surface wave (also known as surface acoustic wave, or SAW) technology
• Pure-glass touchscreens for superior image clarity, resolution, and light transmission
• Durable, scratch-resistant glass surface—continues to work if scratched
• Stable "drift-free" operation—for touch response that's always accurate
• Finger, gloved hand, and soft stylus activation
• Fast touch response
• Sensitive touch response—recognizes location and amount of pressure applied
11. SecureTouch Surface Wave Touchscreens
Flat-screen SecureTouch products are made of extra-tough glass substrates that resist vandalism. These touchscreens incorporate the solid-glass and coating-free construction of Elo's proven IntelliTouch products.
How to connect touchscreen on your own computer?
The Add-On Kit can be easily mounted on ANY monitor / Laptops/POS systems and used for ANY mouse driven application.
It also help childrens to start learning how to use computer without the difficulty of using the mouse.
Easily mounts on ANY standard computer monitor with simple attachments.
Touchscreens Add-ons and Integrated Touchscreen Monitors
There is main two types of touchscreen products, touchscreen add-ons and integrated touchscreen monitors. Touchscreen add-ons are touchscreen panels that hang over an existing computer monitor. Integrated touchscreen monitors are computer displays that have the touchscreen built-in. Both product types work in the same way, basically as an input device like a mouse or trackpad.
Touchscreens As Input Device
All of the touchscreens that basically work like a mouse. Once the software driver for the touchscreen is installed, the touchscreen emulates mouse functions. Touching the screen is basically the same as clicking your mouse at the same point at the screen. When you touch the touchscreen, the mouse cursor will move to that point and make a mouse click. You can tap the screen twice to perform a double-click, and you can also drag your finger across the touchscreen to perform drag-and-drops. The touchscreens will normally emulate left mouse clicks. Through software, you can also switch the touchscreen to perform right mouse clicks instead.
Development in Touchscreen
Virtually all of the significant touchscreen technology patents were filed during the 1970s and 1980s and have expired. Touchscreen component manufacturing and product design are no longer encumbered by royalties or legalities with regard to patents and the manufacturing of touchscreen-enabled displays on all kinds of devices is widespread.
The development of multipoint touchscreens facilitated the tracking of more than one finger on the screen, thus operations that require more than one finger are possible. These devices also allow multiple users to interact with the touchscreen simultaneously.
With the growing acceptance of many kinds of products with an integral touchscreen interface the marginal cost of touchscreen technology is routinely absorbed into the products that incorporate it and is effectively eliminated. As typically occurs with any technology, touchscreen hardware and software has sufficiently matured and been perfected over more than three decades to the point where its reliability is unassailable. As such, touchscreen displays are found today in airplanes, automobiles, gaming consoles, machine control systems, appliances and handheld display devices of every kind.
The ability to accurately point on the screen itself is taking yet another step with the emerging graphics tablet/screen hybrids.
Ergonomics and usage
An ergonomic problem of touchscreens is their stress on human fingers when used for more than a few minutes at a time, since significant pressure can be required and the screen is non-flexible. This can be alleviated with the use of a pen or other device to add leverage, but the introduction of such items can sometimes be problematic depending on the desired use case (for example, public kiosks such as ATMs). Also, fine motor control is better achieved with a stylus, a finger being a rather broad and ambiguous point of contact with the screen.
Yet all of these ergonomic issues can be bypassed simply by using a different technique, provided that the user's fingernails are either short or sufficiently long. Rather than pressing with the soft skin of an outstretched fingertip, the finger is curled over, so that the top of the forward edge of a fingernail can be used instead. (The thumb is optionally used to provide support for the finger or for a long fingernail, from underneath.) The fingernail's hard, curved surface contacts the touchscreen at a single very small point. Therefore, much less finger pressure is needed, much greater precision is possible (approaching that of a stylus, with a little experience), much less skin oil is smeared onto the screen, and the fingernail can be silently moved across the screen with very little resistance, allowing for selecting text, moving windows, or drawing lines. (The human fingernail consists of keratin which has a hardness and smoothness similar to the tip of a stylus, and so will not typically scratch a touchscreen.) Alternately, very short stylus tips are available, which slip right onto the end of a finger; this increases visibility of the contact point with the screen. Oddly, with capacitive touch screens, the reverse problem applies in that individuals with long nails have reported problems getting adequate skin contact with the screen to register keystrokes (note that styluses do not work on capacitive touch screens nor do gloved fingers).
Future Of Multi-Input Touch Screen
We might heard of touch screen and often use in atm’s,mobile etc but that a standard touch screen allows one input at a time.Can you imagine what if this allows multiple people to use it and allows for Minority Report like features.This sort of screens are are recently demonstrate by Jefferson .Y.Han.Its really awesome have a look on this video
The display of these screen are really super cool as we use now a day’s on TFT display.
Whenever it launches on market, i wish to get one through Loyalty Cards,Well this experiments of multi-input touch screen is revolutionary in the market as it can create many platform for various instruments that needs multi-manpower.
