Input Detection Circuit Layout for Uniform Pen Proximity Sensitivity
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Solution Overview
Problem
The electromagnetic induction method for touch detection in input detection devices experiences variations in detection sensitivity due to position-dependent changes in magnetic field intensity, affecting the accuracy of pen proximity detection.
Innovation Solution
The input detection device employs a configuration with multiple drive electrodes and switches, where the number of switches connected in parallel is adjusted based on the distance from the signal wiring, to maintain consistent detection sensitivity across the detection area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple magnetic field generation coils are arranged at mutually different positions to enable position-dependent detection, then the detection area is expanded, but the signal wiring length increases causing resistance increase and current reduction, resulting in position-dependent magnetic field intensity variations
Solution Approach 1:
The patent applies local quality by making the number of switches connected in parallel position-dependent. Switches closer to the signal wiring have fewer parallel connections, while switches farther away have more parallel connections. This creates a non-uniform distribution that locally compensates for the increased resistance in longer signal wirings, maintaining consistent magnetic field intensity across different positions in the detection area.
Solution Approach 2:
The patent changes the parameter of switch configuration (number of parallel switches) based on position. By varying the number of parallel switches according to distance from the signal wiring, the electrical characteristics of each magnetic field generation coil are adjusted to compensate for positional variations, thereby maintaining uniform detection sensitivity across the entire detection area.
2Measurement precision
If signal wiring length is reduced to minimize resistance and maintain current, then magnetic field intensity becomes more uniform, but the arrangement flexibility of magnetic field generation coils is constrained
Solution Approach 1:
Instead of uniformly reducing all signal wiring lengths, the patent applies local quality by adjusting the number of parallel switches at different positions. This allows the system to accommodate varied coil arrangements with different wiring lengths while maintaining uniform magnetic field intensity through position-dependent switch configuration rather than uniform wiring design.
3Force
If more switches are connected in parallel to increase current to remote coils, then magnetic field intensity increases, but the complexity of the switch control system increases
Solution Approach 1:
The patent applies local quality by making the switch configuration position-dependent rather than uniform. Each position has a specific number of parallel switches tailored to its distance from the signal wiring, creating a graduated complexity profile that matches the actual needs of each location rather than uniformly increasing complexity across the entire system.
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 configuration ensures consistent detection sensitivity regardless of the position, improving the accuracy and reliability of touch detection for both pens and fingers by minimizing variations in magnetic field intensity.
Implementation Method 1
a coil for generating a magnetic field (hereinafter also referred to as a 'magnetic field generation coil') and a coil for detecting the magnetic field
Implementation Method 2
The magnetic field generated by the magnetic field generation coil causes the pen-in coil to create an induced voltage
Implementation Method 3
The magnetic field generated by the pen-in coil according to an amount of charges accumulated in the capacitive element is detected by the magnetic field detection coil
Data Source
AI summary
Provided is an input detection device capable of suppressing a change in detection sensitivity depending on a position. The input detection device includes: signal wirings having end portions, and arranged so as to extend in a first direction; drive electrodes each extending in a second direction crossing the first direction, and arranged in parallel to the first direction; a plurality of first switches arranged between the end portions of the drive electrodes and the signal wirings; a drive signal circuit supplying a drive signal to the end portions; and a selection circuit controlling the first switches in detecting proximity of an external object.