Touch Signal Timing for Finger and Stylus Position Detection
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Solution Overview
Problem
Conventional touch sensors struggle to accurately distinguish and calculate the positions of different touch objects, such as fingers and stylus pens, when they come into contact simultaneously due to indistinguishable received signals.
Innovation Solution
A touch apparatus and method that applies distinct driving signals during different periods to differentiate between touch objects, using a first driving signal to identify touch objects like fingers and palms, and a second driving signal to identify stylus pens, with threshold settings to filter and calculate touch coordinates accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single driving signal is applied to touch electrodes, then the touch sensor can detect touch input, but different types of touch objects (e.g., finger and stylus pen) cannot be distinguished when they contact simultaneously
Solution Approach 1:
The patent divides the detection period into multiple time slots (first period and second period) and applies different driving signals in each period. This temporal segmentation allows the system to distinguish between different touch objects by detecting which driving signal produces which detection signal, thereby resolving the ambiguity when multiple objects contact simultaneously.
Solution Approach 2:
The patent employs periodic driving signals with different characteristics (first driving signal and second driving signal) applied in alternating periods. This periodic action enables the system to differentiate touch objects based on the periodicity and characteristics of the received detection signals, improving both differentiation capability and position calculation accuracy.
2Measurement precision
If threshold is set to filter detection signals, then signal strength differentiation is achieved, but false filtering may occur when multiple objects are present
Solution Approach 1:
The patent performs preliminary signal filtering by setting a threshold to identify valid touch signals before processing the touch coordinates. This preliminary action ensures that only signals with sufficient strength (indicating actual touch objects rather than noise) are processed further, improving both signal differentiation accuracy and touch signal validation reliability.
Data Source
AI summary
An exemplary embodiment of the present invention provides a touch apparatus including: a touch panel configured to include a plurality of touch electrodes; a touch driver configured to apply a first driving signal to a first touch electrode of the touch electrodes during a first period, and a second driving signal to the touch electrodes during a second period subsequent to the first period; and a touch controller configured to determine a detection signal as a valid touch signal based on whether a signal strength of the detection signal received in response to the first driving signal exceeds a first threshold during the first period, wherein the detection signal include at least one of a first detection signal generated by a first touch object and a second detection signal generated by a second touch object, and the first detection signal is determined as a valid touch signal, while the first threshold is set to filter the second detection signal.