Touch Screen Testing
Automatic production test and calibration for touch screen, touch displays, press-sensible actuators
Touch displays are the standard interface between the user and any kind of electronics – in consumer devices such as smartphones, tablets, TV screens and wearables, but also in industrial equipment control panels, automotive infotainment, and monitoring systems. Their correct working can be guaranteed only by complete touch screen testing and calibration procedures, performed on each and every device at the end of the manufacturing process.
While display and touch screen testing is often carried out manually, SPEA equipment is able to perform a fully automatic touch performance test and calibration on resistive and capacitive displays, microLED displays, as well as on any touch-enabled smart devices with press-sensible and touch-sensible surfaces. This brings the advantages of higher throughput, lower cost of test, full traceability and repeatability of test results.
Accurate human gesture simulation for testing your touch screens
A reliable functional test is carried out by accurately simulating the pressure of human fingers on the device under test. High-speed, high-accuracy robotic actuators act as real human fingers, perfectly simulating the different pressing forces to verify the correct display working. They are able to simulate all real operations on the displays, for both touch-sensible and press-sensible surfaces, thanks to programmable force actuators, featuring programmable controlled force ranging from grams to kilograms, programmable speed, and real-time feedback on the applied force.
Many functions of the touch screen can be simulated and tested:
- Single-finger gestures: tap, press, swipe, drag, double tap, multi tap, circle and path, fingerprint identification
- Multi-finger gestures: tap, swipe, zoom in/out, rotate
Additional Multi-Function Tests
In addition to the robotic touch testing, the test system is also able to carry out a variety of different tests, so to verify all the product characteristics within a single test stage:
Surface planarity test. The tester can measure any surface deflection with extremely accurate, laser-based micrometers.
Optical inspection. Pattern matching test, dead pixel recognition, backlight brightness and color test can be performed to ensure the display is defect-free, with an accuracy able to verify the goodness of every pixel also on the newest microLED technologies.
Electrical test. The test system can house all the resources to contact and test electrical and electronic parts of the device, recognizing defective parts and detecting process defects (such as open pins and short circuits)
Acoustic test. Correct sound emission from the device (e.g. when a buzzer is present) can be verified via dedicated, robotic units. Extreme accuracy can be guaranteed by anechoic chambers.
NFC test. In case the device includes an NFC antenna, the test system can verify the correct protocol communication.
Performance and robustness for automated touch screen testing
All equipment components are based on state-of-the-art technology for the purpose of robustness, durability, reliability through time, and minimized maintenance.
The robotic architecture is based on full linear motion technology with absolute linear encoders, which ensures:
- Extreme precision and accuracy of the finger positioning
- No need for homing procedures, since the system is able to self-monitoring the actual finger position at any moment, with sub-micron resolution
- No performance drift over time, no influence brought by thermal expansion.
- Automatic calibration, thanks to built-in axes calibrators.
SPEA systems run standard test sequences on all kinds of devices. This brings reliable, repeatable, consistent test results, exactly replicated on every machine. The system software is able to record and analyze the test results, giving a powerful tool to monitor product quality and process quality.