Capacitive Input Device Merging Detection Circuits
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Solution Overview
Problem
Existing input devices for electronic devices, such as mobile phones, require complex internal configurations due to the need for separate circuits to detect capacitance changes and electrical connections, leading to increased costs, manufacturing difficulties, and size constraints.
Innovation Solution
A simplified input device design that uses a single detection portion to detect both position changes and pressing operations through capacitance changes, eliminating the need for separate circuits and reducing internal complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate circuits are used to detect capacitance changes and electrical connections, then detection accuracy is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the capacitance change detection circuit and the electrical connection detection circuit into a single integrated detection circuit. This unified circuit uses a common electrode structure to detect both types of inputs through capacitance changes, thereby reducing device complexity and manufacturing cost while maintaining detection accuracy for both touch and press operations
Solution Approach 2:
The detection circuit is designed with multi-functionality to handle both capacitance change detection (for touch position) and electrical connection detection (for press operation) using the same circuit architecture. This universal approach allows a single circuit to perform multiple detection functions, simplifying the overall device structure
2Reliability
If multiple detection circuits are employed, then detection reliability is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent merges multiple detection circuits into one integrated circuit that can reliably detect both touch position and press operations. This consolidation maintains detection reliability by ensuring both functions operate within a unified, controlled circuit environment while significantly improving ease of manufacture through reduced component count and assembly steps
3Measurement precision
If separate detection circuits are used, then detection precision is improved, but device size increases
Solution Approach 1:
The patent combines position detection and press operation detection into a single detection circuit, which maintains position detection precision while reducing the space required for multiple separate circuits. This integration is particularly beneficial for mobile devices where space is constrained, allowing precise input detection without increasing overall device size
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 design reduces costs, simplifies manufacturing, and downsizes the device while preventing rapid current increases and contamination-related failures, maintaining detection sensitivity and reliability.
Implementation Method 1
a detection portion that detects a capacitance change at the switch element
Implementation Method 2
detects a capacitance change when the movable electrode portion is displaced due to pressing operation of the switch element
Data Source
Figure 1~2
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Figure 6~7
AI summary
An input device includes an insulation substrate, a switch element provided on the substrate, and a detection portion that detects a capacitance change at the switch element. The switch element includes a fixed electrode portion that is provided on the substrate, and a movable electrode portion that is provided on a main surface side of the substrate, at least part of the movable electrode portion being elastically displaceable toward a direction approaching and leaving the fixed electrode portion. The movable electrode portion is displaceable toward a direction approaching the fixed electrode portion due to pressure from an object to be detected that is an electric conductor. The detection portion is capable of detecting a capacitance change caused by the object to be detected approaching and leaving the movable electrode portion and a capacitance change between the movable electrode portion and the fixed electrode portion produced by displacement of the movable electrode portion due to pressing. The fixed electrode portion is electrically insulated with respect to the movable electrode portion and is connected to ground.