CSI KEYBOARDS offers touchscreen products with some of the most widely used touchscreen technologies. Each type of screen has unique characteristics that can make it the best choice for certain applications.
Matrix touch screen is the preferred solution for economic applications requiring little effort on installation.
Resistive: Resistive touchscreen technology is, essentially, two conductive layers of material separated by a small gap. When an area is pressed together by the user, a contact is made. These layers are usually composed of a glass backer, with a conductive coating of ITO on its face, an air gap, and a polyester cover sheet with ITO on the inside, and a clear hard coat on the outside facing the user. When the polyester layer is pressed by the user, the two ITO coatings make contact with one another, and the controller reads it as an activation in a specific part of the grid. When dealing with resistive touchscreens, the most common types are a 4-wire and a 5-wire.
4 wire: The 4-wire resistive touchscreen is the most basic touchscreen technology, using both the ITO on the glass and the ITO coating on the polyester to act as a grid to read activations. Because the ITO is coated on such a flexible material, it is known to wear over time and is also vulnerable to inaccuracies due to varying temperatures in its environment as the polyester can expand and contract. Therefore, the technology is not known for its durability or accuracy since it relies on the weaker polyester layer of material to form the grid. While it is the least expensive touchscreen technology, the polyester is susceptible to scratching, inaccuracy, and reduced light transmission from the display, which takes away from the optical clarity.
5 wire: While 5-wire resistive technology still uses a top layer of polyester, it is not used to form the electronic grid as it was in the 4-wire touchscreen. Instead, the top polyester layer is only used as a voltage probe, which means that the weakest layer of the construction is not used in forming the grid. Because the entire X-Y grid is created using the ITO coating on the glass layer only, it can accept a higher volume of accurate activations from the user making it a much more reliable touchscreen than the 4-wire.
Capacitive: Capacitive touchscreen is different from resistive as it relies on the user's own conductive finger to cause "on" activation, as a field is created on the face of the touchscreen using only one coating of conductive material. When an area of the touchscreen comes into contact with another conductive object, such as a finger, the sensors in the corners of the touchscreen are able to detect what area was activated.
Surface Capacitive: Surface capacitive touchscreens are the most basic form of the technology as layer of glass is coated with a clear ITO, creating an exposed conductive layer of material. When the user comes into contact with the touchscreen, it disrupts the electrostatic field and is read as an activation by the sensors placed in each corner of the touchscreen. Since the technology dismisses the thin conductive polyester layer, which needed to be flexed in order to cause an activation, it is more rugged than the resistive touchscreen. However, it is less accurate than the 5-wire touchscreen, needs to be activated with a bare finger (no gloved applications) and needs to be calibrated.
Projected Capacitive: The projected capacitive touchscreen is essentially a more ruggedized and accurate version of the surface capacitive touchscreen. This is made possible by the etching of the conductive material, forming a grid. This grid not only allows for more accurate activation, but also allows for the ITO to be placed behind another layer of reinforced glass for added protection. This added layer in front of the ITO is only allowed with Projected Capacitive touchscreens.
The Surface Acoustic Wave (SAW) technology is one of the most advanced touch screen types. The technology is based on two transducers (transmitting and receiving) placed for the both of X and Y axis on the touch panel. The other element of SAW is placed on the glass, called reflector. The controller sends electrical signals to the transmitting transducer, and the transducer converts the signal into ultrasonic waves and emits to the reflectors that are lined up along the edge of the panel. After the reflectors refract waves to the receiving transducers, the receiving transducer converts the waves into an electrical signal and sends it back to the controller. When a finger touches the screen, the waves are absorbed, causing a touch event to be detected at that point.
Because the panel is all glass, there are no layers that can be worn, giving this technology the highest durability factor and also the highest clarity. Compared to resistive and capacitive technologies, it provides superior image clarity, resolution, and higher light transmission.
This technology is recommended for ATMs, Amusement Parks, Banking and Financial Applications, public information kiosks, computer based training, or other high traffic indoor environments.