Optical Touch Panel Interference Signal Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing touch systems face challenges in distinguishing optical touch signals from interference signals, leading to recognition errors, especially when external or internal light interferes with the optical sensors.
Innovation Solution
The implementation of an optical touch panel device and touch pen system that includes a pattern analyzer to detect and compare optical signal patterns, an interference controller to determine if the signal is an interference signal, and a wireless transmitter to adjust the signal pattern and operation clock, allowing the touch pen to change its optical signal pattern to prevent misrecognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical signals are used for touch recognition, then touch sensitivity is improved, but interference signals from external or internal light sources cause recognition errors
Solution Approach 1:
The patent applies periodic action by using operation clocks to generate time-periodic optical signals from the touch pen and corresponding scanning periods in the optical touch panel. The touch pen emits optical signals at regular intervals synchronized with the panel's scanning cycles, creating distinct temporal patterns that differentiate valid touch signals from continuous interference light. This periodic modulation allows the system to recognize touches based on timing patterns rather than continuous light presence.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting the operation clock frequency and optical signal patterns based on detected interference conditions. When interference is detected, the system changes the temporal parameters (scanning period, operation clock frequency) and spatial parameters (optical signal distribution patterns) to avoid the interference frequency and improve signal differentiation. This adaptive parameter adjustment enables the system to maintain accuracy under varying interference conditions.
2Speed
If the optical touch panel scans continuously to detect touches, then touch detection speed is improved, but interference signals are more frequently detected causing errors
Solution Approach 1:
The patent implements feedback mechanisms where the optical touch panel continuously monitors detected optical signals and provides feedback about interference conditions to the touch pen and control system. The system analyzes the detected signal patterns, identifies interference based on mismatched temporal patterns or excessive intensity, and adjusts subsequent scanning and signal generation accordingly. This closed-loop feedback enables the system to maintain high detection speed while dynamically adapting to interference conditions to preserve reliability.
Solution Approach 2:
The patent applies dynamics by making the scanning period and operation clock frequency adjustable rather than fixed. The system dynamically modifies the scanning rate and signal generation timing based on real-time interference detection. When interference is present, the system can slow down scanning or change temporal patterns to avoid interference frequencies; when no interference is detected, it operates at maximum speed. This dynamic adaptation resolves the contradiction between speed and reliability.
3Device complexity
If the touch pen uses a fixed optical signal pattern for button functions, then system simplicity is improved, but interference signals with similar patterns cause misrecognition
Solution Approach 1:
The patent makes the optical signal patterns dynamic rather than fixed. The touch pen can change its optical signal patterns based on feedback from the optical touch panel about detected interference. When interference matching a particular pattern is detected, the system switches to alternative patterns with different temporal or spatial characteristics. This dynamic pattern selection maintains system simplicity by using a limited set of predefined patterns while achieving high reliability through adaptive pattern switching.
Solution Approach 2:
The patent employs parameter changes in the optical signal patterns, varying temporal parameters (pulse width, frequency, duty cycle) and spatial parameters (light distribution pattern) to create distinguishable signal characteristics. By changing these parameters based on detected interference conditions, the system can differentiate between valid button presses and interference signals even when using a relatively simple set of base patterns. This parameter variation enables reliable function recognition without requiring an exhaustive number of distinct patterns.
Data Source
AI summary
A touch system including an optical touch panel and a touch pen, and a method of controlling an interference optical signal in the touch system. The optical touch panel device includes: a pattern analyzer detecting a pattern of an optical signal by scanning an optical touch panel, and comparing a detected pattern with patterns designated to button functions of a touch pen; a touch location detector recognizing a detected location of the optical signal as a touch location, if the detected pattern corresponds to a first pattern designated to a button function; an interference controller determining the optical signal as an interference signal, if a detected region of the optical signal exceeds a critical range; and a wireless transmitter outputting a control signal to the touch pen so that the touch pen may change the first pattern designated to the button function to a second pattern.