What Is The Response Time Of Touchscreen?

The response time is defined as the time between the finger touch event on the touch screen and the interrupt signal generated by the touch screen controller. The measurement method is to electronically touch the environment of the simulated finger touch screen, or move a simulated finger on the panel. Response time of touchscreen is especially important. Because it directly affects the speed at which users move their fingers on the screen, perform panning or flicking operations, and use their fingers or pens to write on the screen. A touch screen with a slow response time will have a short pause and no movement can be detected.

The response time of  touchscreen is part of the system response time:

1. X, y axis scan.

The time it takes for the touch screen controller to scan and measure changes in capacitance on the sensor.

2. Finger detection.

Compare the change of the panel capacitance with the pre-defined default value of the finger. If the change range exceeds the default value of the finger, the finger touch will be detected.

3. Finger position.

Calculate based on the result data obtained by multiple sensors to determine the actual position of the finger.

4.Finger tracking.

When there are multiple fingers on the sensor, it can identify and assigne each finger a unique identification symbol.

5. Interrupt delay.

Refers to the delay between indication and service on the host. In most systems, this delay does not exceed 10 (Vs).

6. Communication.

Generally, the system uses I2C at 400kHz, or SPI at 1MHz to communicate with the host.

Technology Shortens Response Time

On the market, some people will use many technologies to shorten the response time. Therefore,the key lies in the intelligence of the touch screen chip. The more creative method only needs to scan part of the screen to detect the finger position. When it detect the finger , it can quickly scan and calculate the actual position of the finger, thereby saving power consumption and time. Another technique is parallel processing, which uses different hardware components for scanning, finger processing, and communication. Synchronize these tasks. Using highly optimized algorithms for finger detection, finger positioning and finger identification (ID) can shorten processing and response time.