How to Test a Touchscreen

By Kent Tukeli

Test a touchscreen to determine its quality.
i Smartphone image by Dominator from

As the popularity of smart phones rises, more manufacturers are entering the mobile marketplace in an attempt to profit from a red-hot market. Touchscreens are a vital component of smart phones, providing users with an easy method of controlling the user interface. Testing a touchscreen on a smart phone is essential to confirming the quality and usefulness of the phone. Using a simple drawing program can test the quality of a touchscreen. Android users can download applications specifically designed to determine screen issues that may exist.

Open an application on the smart phone that enables the user to draw freely. Download a program if it is not already available.

Draw a series of diagonal lines across the screen using a single finger. Make the lines parallel to each other, about a half-inch apart.

Draw an intersecting set of parallel, diagonal lines across the screen, creating a diamond pattern on the touchscreen. Take a close look at the results. Wavy lines suggest difficultly tracking finger movement, which could be a result of software, hardware or calibration issues. The lines should be straight all the way to the limits of the touchscreen. Lines that start curving at the edges of the screen indicate a lack of sensitivity in those regions.

Use different finger pressure to test the sensitivity of the touchscreen. Some screens have difficulty reading light touches and require heavier screen contact.

Android-specific Touchscreen Tests

Download "Screen Test" onto your smart phone and run the application.

Tap the screen to cycle through the various solid color images displayed by "Screen Test," looking for pixels that retain only one color. Look for light pixels in dark backgrounds and vice versa. These indicate dead pixels on the touchscreen.

Check to make sure the white lines are clearly drawn inside the gray boxes displayed when testing the touchscreen with the application. Blurred white lines or pixels that bleed off the edge of the screen suggest crosstalk, resulting in pixel smudging.

Download "Multi-touch Visible Test." Open the application. Put two fingers on the opposing corners of the touchscreen and move them towards each other, passing through the center of the screen. Observe the dots to see if they lag behind or switch fingers, indicating a potential defect in the touchscreen.

Test the amount of different input points available on the touchscreen by placing multiple fingers on the screen. Sensor issues may exist when fewer dots are detected than normally available.