Active Capacitive Touch Pen Varistor Pressure Detection
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Solution Overview
Problem
Conventional capacitive touch devices face challenges in precision position detection, particularly in handheld devices, where more precise and efficient detection is required, necessitating the use of pens for improved accuracy.
Innovation Solution
An active capacitive touch pen is designed with a varistor to determine the degree of pressure applied, utilizing a casing unit, circuit unit, power supply unit, and pen head unit, where the varistor is connected to the circuit substrate and an elastic structure transmits pressure, allowing for varying line thickness on a handwritten board based on applied pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a capacitive touch control device uses a finger or simple conductor for input, then the device is easy to operate and has long service life, but the position detection precision is insufficient
Solution Approach 1:
The patent introduces a specialized pen as an intermediary tool between the user and the capacitive touch screen. The pen incorporates a varistor and elastic structure that mediates the pressure detection function, enabling precise position detection without requiring complex sensor arrays or multiple sensors. The pen acts as a pressure-transmitting intermediary that converts mechanical pressure into electrical signal variations for precise detection.
Solution Approach 2:
The patent changes the operational parameter from simple contact detection to pressure-based detection. By incorporating a varistor that changes resistance based on applied pressure, the system transitions from binary touch detection to continuous pressure measurement, enabling precise position detection while maintaining simple capacitive touch hardware.
2Measurement precision
If a resistive touch control device is used, then position detection can be achieved, but significant force must be applied to a very small area causing deformation
Solution Approach 1:
The patent replaces the mechanical deformation-based resistive touch mechanism with an electrical pressure-sensing mechanism. Instead of relying on physical deformation of a resistive layer, the system uses a varistor that detects pressure through electrical resistance changes, eliminating the need for concentrated mechanical force on a small area while maintaining precise position detection.
3Measurement precision
If an electromagnetic touch control device is used, then position detection is achieved, but a special battery-powered pen is required
Solution Approach 1:
The patent enables the pen to be self-powered by utilizing the user's own mechanical action (pressing the pen tip) as the power source. The varistor converts the mechanical pressure applied during normal writing into electrical energy for detection, eliminating the need for separate battery power while maintaining precise position detection capability.
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
The active capacitive touch pen enhances precision in position detection by using a varistor to measure pressure, enabling pens to produce lines of different thicknesses, thereby improving operational smoothness and accuracy in capacitive touch input systems.
Implementation Method 1
at least one varistor disposed inside the pen-shaped casing structure and electrically connected to the circuit substrate, wherein a predetermined pressure generated by pushing the pen head structure is transmitted to the at least one varistor through the elastic structure
Implementation Method 2
an elastic structure disposed between the pen head structure and the at least one varistor, wherein a predetermined pressure generated by pushing the pen head structure is transmitted to the at least one varistor through the elastic structure
Implementation Method 3
the working principle of a capacitive touch control device relies on capacitive coupling, which takes place as soon as the capacitive touch sensor is touched by a conductive object
Data Source
AI summary
An active capacitive touch pen includes a casing unit, a circuit unit, a power supply unit and a pen head unit. The casing unit includes a pen-shaped casing structure. The circuit unit includes a circuit substrate disposed inside the pen-shaped casing structure and at least one varistor disposed inside the pen-shaped casing structure and electrically connected to the circuit substrate. The power supply unit includes at least one power supply component disposed inside the pen-shaped casing structure and electrically connected to the circuit substrate. The pen head unit includes a pen head structure movably disposed inside the pen-shaped casing structure and an elastic structure disposed between the pen head structure and the varistor. The pen head structure has an exposed contacting portion exposed from the pen-shaped casing structure. Whereby, a predetermined pressure generated by pushing the pen head structure is transmitted to the varistor through the elastic structure.