A touch screen or multi touch screen is an integrated unit consisting of an input and output component. The touch screen is generally layered above an ordinary computer visual display of some sort. The screen is most often the LCD or LED screen while the device is most often a cell phone, laptop, or tablet. These devices are capable of computing via resistive, capacitive, infrared, digital or optical signals. The multi touch screen can be implemented in a variety of display configurations such as a text display, a graphics display, a touch screen, or as a monitor for monitoring input events. It is widely used in business and consumer applications.
Touch screen technologies evolved from the use of the stylus or point-and-click systems to the present day multitouch interfaces using finger pressure or other finger gestures. The first multitouch devices were designed for the UNIX console. Modern versions are available for Windows CE, Windows Mobile, and Symbian operating systems. The multi touch screen interface allows interactive input devices such as a mouse, keyboard, pointing devices, touch screen displays and digital cameras to interact with the computer.
Multi touch screen technology constitutes multi-touch sensing technologies that use surface acoustic wave transducers to detect the touch. The signal is then amplified by a pair of electrodes driven by an electric charge. The electrical charge makes the pressure change which causes the relative pressure between the two active points on the screen. These changes are translated by the CPU based on the frequency of the electrical signal and the position and orientation of the cursor in the touch screen. These signals are transformed into pixel data that form a virtual image of the touch screen.
There are some advantages of using a touch screen. In fact there are many, but I will highlight only three here. First, users can increase their finger sensitivity to achieve greater accuracy when inputting data. Second, the image clarity achieved is improved over existing LCD touch screen displays. And third, the cost of implementing a touch screen and hardware changes to support it are lower than those associated with existing liquid crystal displays (LLCD). However, these advantages are offset by the need to provide power and an electrical interface for the device and for the possible disadvantages of implementing it.
The major disadvantages of using touch screens relate to the finger’s movement and the possibility of damage to the electronic components when touching the screen. It has been shown that people can inadvertently scratch the monitor screen if they hold the pen or stylus close to it. Touching the screen can also result in a minor electric current leak. This leakage current is typically not enough to damage your electronic components. The problem however, is that touch screens do not insulate the glass from heat. The heat generated causes the solder to melt which can lead to shorting or even burning of the glass.
The other major disadvantage of a touch screen display is related to the use of capacitive touch screen technology. Capacitive touch screen technology uses a combination of surface acoustic wave technology and capacitance to detect finger pressure and movement. These signals are then translated into graphical user interface controls such as on/off light and volume controls. Unfortunately, the advantage of using this type of technology comes at a price. The rapid fluctuations in capacitance levels produce an inconsistent signal which can result in annoying “jitter” when using the touch screen.
The third type of technologies used in modern touch screen monitors is resistive and optical. A resistive controller operates between two conductors, usually long pins like resistive flex and ribbon cables. One polarity of the signal controls the brightness of the display, while a different polarity of the signal controls the response time of the display. The resistive controller works well for displaying simple patterns or images such as text. However, the lack of direct contact with the screen can limit the ability to show fine gradation of details or to display motion. Also, if one of the two connections connecting the display to the logic unit falls off, the display will still respond, but the response time will be extremely slow.
Touch screen protectors are a versatile solution that can prevent damage from accidental falls and also allow for a high level of comfort for the user. Available in a variety of materials, including polycarbonate and tempered glass, touch screen protectors help maintain the integrity of the touch screen without hindering the ergonomic functions of the monitor. Prices for touch screen protectors vary according to the type of materials used in their construction and the amount of protection offered. In general, the higher the quality of the protector, the more expensive it will be.