Surface-Wave touch technologies have a glass overlay with
transmitting and receiving piezoelectric transducers for both the X
and Y axes. The touchscreen controller sends a electrical signal to
the transmitting transducer, which converts the signal into
ultrasonic waves within the glass. These waves are directed across
the front surface of the touchscreen by an array of reflectors.
Reflectors on the opposite side gather and direct the waves to the
receiving transducer, which reconverts them into an electrical
signal—a digital map of the touchscreen surface.
When you touch the screen, you absorb a portion of the wave
traveling across it. The received signal is then compared to the
stored digital map, the change recognized, and a coordinate
calculated. This process happens independently for both the X and Y
axes. By measuring the amount of the signal that is absorbed, a
Z-axis is also determined. The digitized coordinates are transmitted
to the computer for processing.
Surface Acoustic wave (SAW)
Glass panel with transducers attached to the front surface of
Standard deviation of error is less than 0.080 in
(2.03 mm). Equates to less than ±1% error on most displays.
More than 100,000 touchpoints/in² (15,500
Typically less than 3 ounces (85 grams).
known wear-out mechanism, as there are no layers, coatings, or
moving parts. SAW technology has been operationally tested to more
than 50 million touches in one location without failure, using a
stylus similar to a finger (Unlimited touch life).
Unit can be sealed to protect against splashed liquids, dirt,
Surface durability is that of glass, Mohs' hardness
rating of 7.
4096x4096, size independent.
up to 92%.
Operating: -20°C to 50°C;
Storage: -40°C to 71°C.
Humidity: 90% RH at 40°C, no
The active area of the touch screen is resistant to
all chemicals that do not affect glass.
Meets Level 4 (15 kV air/8 kV contact
Meets the requirements of UL 94HB.
Tempered SAW only
Construction: Pure 6mm-thickness heat strengthened glass with
to the beveled edge of the
2. Break Resistance
UL-1950 Steel Ball Drop Test
A 1-pound steel ball drops from
height of 130 cm onto the center of the
Protected SAW only
Pure 6mm-thickness heat strengthened glass with
On the edge of the glass surface.
reflectors and transducers are sealed inside the ABS plastic
2. Break Resistance
Steel Ball Drop Test
ABS plastic frame around the panel prevents dust and dirt
accumulating on the reflectors and
is applied to the gap between the ABS plastic frame and
substrate to prevent water infiltration.
Method: Set the touch screen horizontally, and pour water on
panel surface without overflow over the ABS plastic frame.
surface is soaked in water for 1 hour. The panel is in
after water poured out and dried.