Resistive Touch Panel Circuit for Adjacent Region Discrimination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Resistive touch panels struggle to accurately differentiate between inputs on adjacent regions with narrow spacing, leading to erroneous operations due to noise interference and coordinate reciprocity, especially in multi-functional devices like touch input devices with buttons and sliders.
Innovation Solution
Implementing a control circuit for resistive touch panels with distinct resistance per unit length in adjacent regions, utilizing measurement units to determine touch coordinates based on impedance or voltage ranges, and incorporating two-point touch detectors to prevent erroneous outputs in cases of simultaneous touches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If adjacent regions are placed close together to increase functional density, then device functionality is improved, but coordinate detection accuracy deteriorates due to noise interference and coordinate reciprocity
Solution Approach 1:
The patent applies local quality by assigning different resistance per unit length characteristics to different regions of the touch panel. Specifically, the first region has a first resistance per unit length while the second region has a second resistance per unit length, creating distinct electrical signatures for each functional region. This allows the control circuit to differentiate between touches in adjacent regions even when they are closely spaced, thereby maintaining measurement precision while enabling high functional density.
2Adaptability or versatility
If different functions are allocated to adjacent regions to widen application scope, then adaptability is improved, but input discrimination accuracy deteriorates due to narrow spacing
Solution Approach 1:
The patent implements local quality by creating regions with distinct resistance characteristics. The first region allocated for one function has a different resistance per unit length than the second region allocated for another function. This enables the control circuit to reliably determine which region was touched based on impedance measurements, thereby maintaining input discrimination accuracy while expanding application scope through multi-functional regions.
Solution Approach 2:
The patent applies parameter changes by varying the resistance per unit length parameter across different regions. By controlling the resistance characteristics during manufacturing, each functional region develops a unique electrical parameter profile. The control circuit utilizes these parameter differences to accurately discriminate between inputs on different functions, even when regions are adjacent with narrow spacing.
3Difficulty of detecting and measuring
If impedance measurement is used to detect touch coordinates, then measurement capability is improved, but susceptibility to noise and coordinate reciprocity worsens
Solution Approach 1:
The patent mitigates noise interference by combining impedance measurement with knowledge of local resistance characteristics. Each region's known resistance per unit length serves as a reference that helps the control circuit distinguish genuine touch signals from noise. The distinct electrical signatures of different regions create a more robust measurement system that is less susceptible to random fluctuations and interference.
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
Enhances the accuracy of coordinate detection and input discrimination between adjacent regions, even in narrow spacing scenarios, by expanding voltage ranges and preventing erroneous operations due to two-simultaneous touches.
Implementation Method 1
a measurement unit that measures an electric signal having a correlation with impedance between two wires which are lead out from the resistive touch panel
Implementation Method 2
a measurement unit that measures a voltage of a sensing wire in a state of applying a predetermine the voltage to the resistive touch panel
Data Source
AI summary
A control circuit controls a two-wire resistive touch panel. The two-wire resistive touch panel includes a first region and a second region which are adjacent to each other in a coordinate axis direction (X direction), and the first region has resistance per unit length lower than resistance per unit length of the second region. A measurement unit measures an electric signal having a correlation with impedance between two wires which are lead out from the resistive touch panel. A processing unit (i) determines that the first region is touched when the electric signal or the impedance obtained from the electric signal is included in a predetermined first range, (ii) determines that the second region is touched when the electric signal or the impedance obtained from the electric signal is included in a predetermined second range, and generates a touched coordinate.