19-04-2011, 04:40 PM
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Introduction
A touchscreen is an easy to use input device that allows users to control PC software and DVD video by touching the display screen.
A touch system consists of a touch Sensor that receives the touch input, a Controller, and a Driver. The touch screen sensor is a clear panel that is designed to fit over a PC. When a screen is touched, the sensor detects the voltage change and passes the signal to the touch screen controller. The controller that reads & translates the sensor input into a conventional bus protocol (Serial, USB) and a software driver which converts the bus information to cursor action as well as providing systems utilities
As the touch sensor resides between the user and the display while receiving frequent physical input from the user vacuum deposited transparent conductors serve as primary sensing element. Vacuum coated layers can account for a significant fraction of touch system cost. Cost & application parameters are chief criteria for determining the appropriate type determining the system selection. Primarily, the touch system integrator must determine with what implement the user will touch the sensor with & what price the application will support.
Applications requiring activation by a gloved finger or arbitrary stylus such as a plastic pen will specify either a low cost resistive based sensor or a higher cost infra-red (IR) or surface acoustic wave (SAW) system. Applications anticipating bare finger input or amenable to a tethered pen comprises of the durable & fast capacitive touch systems. A higher price tag generally leads to increased durability better optical performance & larger price.
The most commonly used systems are generally the capacitive & resistive systems. The other technologies used in this field are Infrared technology & SAW (surface acoustic wave technology) these technologies are latest in this field but are very much expensive.
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.
TouchSensor
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.
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 Tor 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.
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.
Comparing Touch Technologies
Each type of screen has unique characteristics that can make it a better choice for certain applications.The most widely used touchscreen technologies are the following:
Resistive Wire Technology:
Resistive touch screens consist of a glass or acrylic panel that is coated with electrically conductive and resistive layers made with indium tin oxide (ITO) .The thin layers are separated by invisible spacers.
4-Wire Resistive Touchscreens
4-Wire Resistive touch technology consists of a glass or acrylic panel that is coated with electrically conductive and resistive layers. The thin layers are separated by invisible separator dots. When operating, an electrical current moves through the screen. When pressure is applied to the screen the layers are pressed together, causing a change in the electrical current and a touch event to be registered
4-Wire Resistive type touch screens are generally the most affordable. Although clarity is less than with other touch screen types, resistive screens are very durable and can be used in a variety of environments. This type of screen is recommended for individual, home, school, or office use, or less demanding point-of-sale systems, restaurant systems, etc.
Advantages
High touch resolution
Pressure sensitive, works with any object
Not affected by dirt, dust, water, or Affordable touchscreen technology
Disadvantages
75 % clarity
Resistive layers can be damaged by stylus
Less durble then 5-Wire Resistive technology
Introduction
A touchscreen is an easy to use input device that allows users to control PC software and DVD video by touching the display screen.
A touch system consists of a touch Sensor that receives the touch input, a Controller, and a Driver. The touch screen sensor is a clear panel that is designed to fit over a PC. When a screen is touched, the sensor detects the voltage change and passes the signal to the touch screen controller. The controller that reads & translates the sensor input into a conventional bus protocol (Serial, USB) and a software driver which converts the bus information to cursor action as well as providing systems utilities
As the touch sensor resides between the user and the display while receiving frequent physical input from the user vacuum deposited transparent conductors serve as primary sensing element. Vacuum coated layers can account for a significant fraction of touch system cost. Cost & application parameters are chief criteria for determining the appropriate type determining the system selection. Primarily, the touch system integrator must determine with what implement the user will touch the sensor with & what price the application will support.
Applications requiring activation by a gloved finger or arbitrary stylus such as a plastic pen will specify either a low cost resistive based sensor or a higher cost infra-red (IR) or surface acoustic wave (SAW) system. Applications anticipating bare finger input or amenable to a tethered pen comprises of the durable & fast capacitive touch systems. A higher price tag generally leads to increased durability better optical performance & larger price.
The most commonly used systems are generally the capacitive & resistive systems. The other technologies used in this field are Infrared technology & SAW (surface acoustic wave technology) these technologies are latest in this field but are very much expensive.
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.
TouchSensor
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.
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 Tor 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.
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.
Comparing Touch Technologies
Each type of screen has unique characteristics that can make it a better choice for certain applications.The most widely used touchscreen technologies are the following:
Resistive Wire Technology:
Resistive touch screens consist of a glass or acrylic panel that is coated with electrically conductive and resistive layers made with indium tin oxide (ITO) .The thin layers are separated by invisible spacers.
4-Wire Resistive Touchscreens
4-Wire Resistive touch technology consists of a glass or acrylic panel that is coated with electrically conductive and resistive layers. The thin layers are separated by invisible separator dots. When operating, an electrical current moves through the screen. When pressure is applied to the screen the layers are pressed together, causing a change in the electrical current and a touch event to be registered
4-Wire Resistive type touch screens are generally the most affordable. Although clarity is less than with other touch screen types, resistive screens are very durable and can be used in a variety of environments. This type of screen is recommended for individual, home, school, or office use, or less demanding point-of-sale systems, restaurant systems, etc.
Advantages
High touch resolution
Pressure sensitive, works with any object
Not affected by dirt, dust, water, or Affordable touchscreen technology
Disadvantages
75 % clarity
Resistive layers can be damaged by stylus
Less durble then 5-Wire Resistive technology
