Capacitive Infrared Touch Sensor Oblique Input Positioning
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Solution Overview
Problem
Existing input detection systems struggle to accurately detect the position of a finger pointed obliquely towards a capacitive touch panel, leading to incorrect input position detection.
Innovation Solution
The system employs a combination of capacitive and infrared sensors to detect the input position. A first position detection processing unit detects the input position at the capacitive sensor, while a second position detection processing unit detects the input position at the infrared sensor. An input position detection processing unit then calculates the accurate input position based on the data from both sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single capacitive sensor is used to detect input position, then the device complexity is low, but the detection precision deteriorates when the user points from an oblique direction
Solution Approach 1:
The patent combines a capacitive touch panel and an infrared sensor into a unified detection system. The capacitive panel detects the X and Y coordinates where the finger makes contact, while the infrared sensor detects the Z-axis position (distance from the panel surface). By merging these two sensor systems, the patent achieves three-dimensional position detection that resolves the oblique pointing accuracy issue while maintaining relatively simple device architecture through integrated sensor mounting and shared processing units.
2Measurement precision
If only capacitive sensor data is processed, then the processing complexity is low, but the detection precision for oblique input directions is insufficient
Solution Approach 1:
The patent transitions from two-dimensional capacitive sensing to three-dimensional position detection by adding the Z-axis component through infrared sensing. The capacitive sensor provides XY coordinates on the panel surface, while the infrared sensor measures the vertical distance from the panel. This dimensional expansion enables accurate detection of oblique pointing directions by considering the three-dimensional spatial relationship between the finger and panel, thereby improving precision without excessive processing complexity through efficient coordinate transformation algorithms.
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
This approach significantly improves the detection accuracy of the input position, even when the user points from an oblique direction, ensuring precise input operations.
Implementation Method 1
a first sensor (22) of capacitive type
Implementation Method 2
a second sensor (23) of infrared type
Data Source
AI summary
A display device includes a first position detection pressing circuit that detects a first position of the input operation at the first sensor, a second position detection pressing circuit that detects a second position of the input operation at the second sensor, and an input position detection pressing circuit that detects the input position with respect to the display panel based on the first position detected by the first position detection pressing circuit and the second position detected by the second position detection pressing circuit.