Capacitive touchscreens are widely used in a variety of industrial and commercial applications due to their sensitivity and multi-touch capabilities, but they are not without their drawbacks. It is vital to understand these common capacitive touch screen faults.
1. capacitive touch screen can not respond to touch
-Foreign objects on the touch screen
When using a capacitive touch screen, the sensing of finger charge is the key to triggering touch control. If there is a foreign object such as dust or grease on the touch screen, it may interfere with the charge transfer from the finger and cause the touch to be unresponsive. In this case, simply wiping the screen gently with a clean, soft cloth is sufficient.
-Damaged or worn touch screen
If the capacitive sensor panel of the touch screen is damaged or worn out, it may also result in unresponsive touch. In this case, the touchscreen needs to be replaced.
-Capacitive touch chip failure
A capacitive touch chip failure can also result in unresponsive touch when there is no problem with the touchscreen itself. In this case, it is necessary to replace the capacitive touch chip.
2. Capacitive touch screen accidental touch or drift
-Capacitive touch chip failure
The main reason for accidental touch or drift of capacitive touch screen is capacitive touch chip failure. In this case, it is necessary to replace the chip.
-Influence of touch screen frame and surrounding environment
Sometimes, the influence of the touch screen bezel or the surrounding environment (e.g., strong backlight conditions) can cause false touches or drift. In this case, adjusting the screen brightness or screen angle can help mitigate the effects.
3. Lack of sensitivity of capacitive touch screen
-The touch cover glass is too thick
If the touch cover glass is too thick, it will reduce the sensitivity of the screen and may even lead to a complete lack of response. In this case it will be necessary to recalibrate the touch firmware to accommodate this thickness of cover glass, which will allow for a more sensitive touch.
-Wearing gloves or hand straps
When gloves or hand straps are worn on the fingers, the capacitive sensing effect of the fingers is affected, resulting in a less sensitive touch screen. The touch screen firmware can also be adjusted to match the glove touch to make the touch more sensitive.
4. Capacitive Touch Screen Skipping
Capacitive touch screen often appear jump point, especially in the sample testing stage. The main reasons include electrostatic interference, unstable voltage, driver error, CTP (capacitive touch screen) short circuit.
Electrostatic interference must be considered during the product design phase. Specifically, the FPC design must include proper grounding. If the customer's environment has significant interference, it is critical to use an electromagnetic film to combat this interference. Additionally, improper connections between the CTP and the main control board can lead to skipping points. It is important to ensure that the program is fine-tuned to be optimal during the sample testing phase. A more serious problem is a short circuit within the CTP itself, usually caused by a short in the sensor or FPC (Flexible Printed Circuit). In this case, if it is a serious defect, the CTP needs to be replaced.
5. Ghost touch
Ghost touch refers to the phenomenon that even if no physical touch occurs on the display, the touch screen device will trigger the command. Ghost touch is usually caused by electromagnetic interference or static electricity, which can lead to cause false inputs and affect the accuracy of touch-based operations.
Ensure proper grounding, use a well-insulated, high-quality shield, and avoid high-static environments. New firmware based on complete device debugging will help.
6. Water Ripple Effect in Capacitive Touch Screens
The water ripple effect in capacitive touch screens is similar to the Newton's ring phenomenon in resistive screens. This effect in capacitive touch screen is actually caused by the gap between the LCM (Liquid Crystal Module) and the CTP (Capacitive Touch Panel). It is also related to the POL (Polarizer) of the LCD module.
If the LCM does not have a metal frame and there is no significant gap between the POL and the frame, then considering full lamination may be a solution. For cases where full lamination is not suitable, choosing a matte POL or increasing the distance between the LCM and CTP may be effective alternatives.
In summary, capacitive touchscreens, while very effective and versatile in a variety of applications, are susceptible to a number of common problems. These include unresponsiveness, accidental touch or drift, sensitivity issues, skipping dots, ghosting touch and water ripple effects. Industry professionals who are aware of common touchscreen problems will not only help to troubleshoot them quickly and effectively, but will also be able to guide them in making informed decisions when selecting and maintaining capacitive touchscreen products.