Technologies of Touch Screen

Infrared Optical Imaging technology

Structure

Infrared optical imaging technology makes use of infrared lights. How is it different from the basic infrared technology?

Let's see the structure of optical imaging technology. Two infrared imaging sensors are located on the both ends of top side. These infrared imaging sensors function as emitters of infrared light as well as imaging sensors. Retro-reflective tapes are located on the three sides (right, left and bottom sides). The sensing method of infrared optical imaging technology will be explained in the next section.

Sensing Method

The infrared lights are emitted from the infrared imaging sensors. These lights are reflected by the retro-reflective tapes on the sides and come back to the infrared imaging sensors from the same angles as emitted. If the touch screen is touched, the infrared light will be blocked and not come back to the infrared imaging sensors.
Naturally, a shadow will appear on the blocked point. The angles between the two infrared imaging sensors and the shadow will be measured.

So, the touched point will be calculated by triangulation?

Yes, that's right.

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