Position Detection Circuit With Dynamic Stylus Thresholding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional position detection systems using capacitance-type touch sensors falsely detect the touch position of a user's hand or finger as the pen position due to the downlink signal from an electronic pen passing through the human body, leading to incorrect position detection.
Innovation Solution
A position detection circuit that includes a first detection circuit for detecting a touch, a second detection circuit for detecting a first indicator's proximity, and a changing circuit that adjusts the threshold for detecting the first indicator based on touch detection, reducing the likelihood of false detection by increasing the threshold when a touch is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a capacitance-type touch sensor is used to detect both pen position and touch position, then both positions can be detected using the same sensor, but false detection occurs where the touch position is incorrectly identified as the pen position
Solution Approach 1:
The patent applies local quality by differentiating the detection method based on the detected object. When a touch is detected, the system switches to a second detection method that uses a different threshold criterion for pen detection. This local adaptation of detection quality ensures accurate pen position detection only when no touch is present, while allowing touch detection to function independently, thereby resolving the false detection issue while maintaining overall detection versatility.
Solution Approach 2:
The patent implements dynamics by making the pen detection threshold dynamic rather than static. The threshold for detecting the pen's downlink signal changes based on whether a touch is detected. When a touch is detected, the threshold is adjusted to prevent false positive pen detections. This dynamic adjustment allows the system to adapt its detection sensitivity to the current operational state, eliminating false detections while preserving the ability to detect both touches and pens accurately.
2Measurement precision
If the threshold for detecting the first indicator is kept low to ensure detection sensitivity, then the first indicator can be detected even when far from the touch sensor, but false detection of the second indicator as the first indicator increases
Solution Approach 1:
The patent applies dynamics by making the detection threshold variable rather than fixed. The threshold for detecting the first indicator's downlink signal is adjusted based on whether a touch of the second indicator is detected. When no touch is detected, a lower threshold maintains high detection sensitivity for the first indicator. When a touch is detected, the threshold is raised to prevent false detection, thus dynamically balancing sensitivity and reliability based on the operational context.
Solution Approach 2:
The patent implements parameter changes by modifying the detection threshold parameter based on the presence of a touch. The system changes the threshold parameter from a low value (for high sensitivity) to a high value (for high reliability) depending on whether a touch is detected. This parameter adaptation allows the system to optimize detection performance for different operational states, preventing false detections while maintaining detection capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively suppresses false detection of the touch position as the pen position by adjusting the detection threshold, ensuring accurate position detection of both the electronic pen and user's touch.
Implementation Method 1
The touch position is detected by detection of capacitive coupling between the hand or finger of the user and the touch sensor
Implementation Method 2
the downlink signal from the electronic pen goes through the human body
Data Source
AI summary
An integrated circuit that is connected to a sensor to detect a position of a stylus that communicates with the sensor and a position of a touch. The integrated circuit includes at least one processor and at least one memory storing firmware that, when executed by the at least one processor, causes the integrated circuit to: detect a touch to an input surface arranged on the sensor; and detect the stylus based on proximity information that indicates proximity of the stylus to the sensor. The integrated circuit, in operation, detects the stylus if the proximity information is greater than or equal to a threshold, and changes the threshold based on a detection result of the touch.