Touch Screen Systems

We offer a variety of interactive touch screen to meet the needs of any application.

Technologies

There are a number of types of touchscreen technology

• Resistive
• Capacitive
• Capacitive & Resistive
• Surface Acoustic Wave (SAW)
• Infrared
• Optical imaging
• Acoustic pulse recognition

Resistive:

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 touchscreen panels are generally more affordable but offer only 75% clarity[citation needed] (premium films and glass finishes allow transmissivity to approach 85%[citation needed]) and the layer can be damaged by sharp objects. Resistive touchscreen panels are not affected by outside elements such as dust or water and are the type most commonly used today. A Nintendo DS is an example of a product that uses resistive touchscreen technology.

Capacitive:

Capacitive sensors work based on proximity, and do not have to be directly touched to be triggered. In most cases, direct contact to a conductive metal surface does not occur and the conductive sensor is separated from the user's body by an insulating glass or plastic layer. Devices with capacitive buttons intended to be touched by a finger can often be triggered by quickly waving the palm of the hand close to the surface without touching.

Capacitive & Resistive:

Whereas people have long been looking for both restive and capacitive touch panels in precisely the identical dimension, it is Omni displays firm commitment to bring to market a unique 2 in 1 product portfolio. Our 2 in 1 touch panel devices offer the greatest advantages of not only providing the high compatibility and stability of the resistive sensor, but also the capacitive sensors unique characteristics such as being workable in very demanding environments, high anti scratch properties and burn resistance.
Our 2 in 1 product portfolio features touch related product makers with one mechanical design available for both resistive and capacitive sensors, benefiting customers with twice the application field. By merely replacing the resistive sensor with the same size capacitive sensor and controller, while maintaining identical utility and device drivers, customers can use their 2 in 1 sensors to work on multiple operating platforms simultaneously. Currently, Omni Displays is the provider of multifunction touch panels in the market.

Surface Acoustic Wave (SAW):

Surface acoustic wave (SAW) technology uses ultrasonic waves that pass over the touchscreen 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 touchscreen panels can be damaged by outside elements. Contaminants on the surface can also interfere with the functionality of the touchscreen.

Infrared:

An infrared (IR) touchscreen panel employs one of two very different methods. One method uses thermal induced changes of the surface resistance. This method is sometimes slow and requires warm hands. Another method is an array of vertical and horizontal IR sensors that detect the interruption of a modulated light beam near the surface of the screen. IR touchscreens 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 touchscreen 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  optical imaging 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 stylis. A downside is that after the initial touch the system cannot detect a motionless finger.

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 touchscreen itself is actually pure glass, giving it the optics and durability of the glass out of which it is made. (APR - Acoustic Pulse Recognition )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.