Pen Type Coordinate Indicator Pressure Detection Mechanism
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Solution Overview
Problem
Conventional pen type coordinate indicators have a narrow detection range for pressing pressure due to the limited deformation of the O ring, leading to erroneous detection when the pen is tilted or held upright, and the phase change of the electric wave is not accurately representative of the applied pressure.
Innovation Solution
Incorporating a coil spring and a silicon rubber as elastic bodies between the first and second ferrite cores, allowing for gradual and precise changes in the distance between their end surfaces, thereby adjusting the inductance value and phase of the electric wave in response to varying pressures, preventing erroneous detection and widening the detection range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an O ring is used as the elastic body between the first and second ferrite cores, then the structure is simple and easy to manufacture, but the detection range for pressing pressure is narrow due to limited deformation
Solution Approach 1:
The single O ring elastic body is segmented into multiple elastic bodies (first elastic body and second elastic body) with different deformation characteristics. The first elastic body has a first modulus of elasticity and the second elastic body has a second modulus of elasticity, creating distinct detection ranges for different pressing pressure levels.
Solution Approach 2:
Different regions of the elastic body system are assigned different local qualities through the use of elastic bodies with different moduli of elasticity. The first elastic body responds to lighter pressing pressures while the second elastic body responds to heavier pressing pressures, optimizing the detection sensitivity for each pressure range.
2Measurement precision
If the O ring is crushed to detect pressing pressure, then the phase change of the electric wave can be detected, but erroneous detection occurs when the pen is tilted or held upright due to limited deformation range
Solution Approach 1:
The elastic body system is designed to dynamically adapt its response characteristics based on the magnitude of the applied pressing pressure. The system transitions from the first elastic body responding to lighter pressures to the second elastic body responding to heavier pressures, maintaining reliable detection across the full range of pressing pressures without erroneous detection from tilting or upright positioning.
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 solution enables precise detection of pressing pressure over a broader range, preventing false positives when the pen is held upright and allowing for sensitive phase changes in response to applied pressure, enhancing the accuracy of position and pressure detection.
Implementation Method 1
at least the first elastic body is elastically deformed by a pressing pressure to cause the end surface of the first magnetic body or the end surface of the second magnetic body to come in contact with the second elastic body
Implementation Method 2
the second ferrite core 102 comes close to the first ferrite core 104, and in response to this action, an inductance value of the coil 105 is changed and thus a phase (resonance frequency) of an electric wave transmitted from the coil 105 of the resonance circuit 116 is changed
Data Source
AI summary
A pen type coordinate indicator for a position input device is provided, which is capable of widening a detection range of a pressing pressure (pen pressure) while preventing erroneous (false) detection. A coil spring (i.e., a first elastic body) and a silicon rubber (i.e., a second elastic body) are interposed between an end surface of a first ferrite core, around which a coil connected to a resonance circuit is wound, and an end surface of a second ferrite core, within the pen. The first and second elastic bodies operate to controllably change (narrow) the distance between the two end faces in accordance with the pressure applied to the pen tip. As a result, an inductance value of the coil wound around the first ferrite core is controllably changed and thus a phase (frequency) of an electric wave transmitted from the resonance circuit to a position detector is controllably changed.