Stylus Pressure Sensing Signal Transmission Using Flexible Printed Circuit

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Solution Overview

Problem

Existing stylus technologies face challenges due to complex structures and high costs associated with pressure sensing signal transmission.

Innovation Solution

The stylus incorporates a main circuit board with a pressure sensing chip, a pressure sensing module with a strain gauge, and a first flexible printed circuit for signal transmission, eliminating the need for a rigid-flexible board.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rigid-flexible board is used to transmit pressure sensing signals, then signal transmission is achieved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvepressure sensing signal transmissionVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the pressure sensing system into separate functional modules: a pressure sensing module with strain gauge, a conducting holder for mechanical support, and a main circuit board with pressure sensing chip. This segmentation eliminates the need for a complex rigid-flexible board while maintaining signal transmission functionality through dedicated components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines the pressure sensing chip directly with the main circuit board, integrating the signal processing function into the existing board structure. This merging eliminates the need for separate rigid-flexible board assemblies, reducing overall structural complexity while maintaining reliable signal transmission.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If a rigid-flexible board is used to transmit pressure sensing signals, then signal transmission is achieved, but manufacturing cost increases

Engineering Contradiction:
Improvepressure sensing signal transmissionVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

By segmenting the pressure sensing system into independent modules (strain gauge, conducting holder, main circuit board), the patent enables standardized mass production of each component, reducing manufacturing costs compared to custom rigid-flexible board assemblies.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces expensive rigid-flexible board assemblies with more economical components: a standard main circuit board, a simple conducting holder, and a strain gauge. These cheaper components achieve the same functional result, significantly reducing manufacturing costs.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Measurement precision

If a strain gauge and conducting holder are used, then pressure sensing is enabled, but device complexity increases

Engineering Contradiction:
Improvepressure sensing capabilityVSAvoidpressure sensing module structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the conducting holder's mechanical support function with the strain gauge's sensing function into a unified pressure sensing module. This integration reduces the number of separate components and simplifies the overall structure while maintaining precise pressure sensing capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The conducting holder serves multiple functions: providing mechanical support for the strain gauge, transmitting applied pressure to the sensing element, and structurally integrating the pressure sensing module with the main circuit board. This multi-functionality reduces the need for additional components, simplifying the overall structure.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 simplifies the structure, reduces costs, and effectively transmits pressure sensing signals, enhancing the stylus's functionality and competitiveness.

Implementation Method 1

a pressure sensing module with a strain gauge, and a first flexible printed circuit for signal transmission

Methodology Applied
Scientific EffectStrain gauge detection: Piezoresistive Effect

Data Source

PatentEP4300271B1Stylus and electronic device component
Publication Date: 2025.06.04 HONOR DEVICE CO LTD
  • EP4300271B1 patent drawingFigure 1
  • EP4300271B1 patent drawingFigure 2
  • EP4300271B1 patent drawingFigure 3

AI summary

This application relates to the stylus field, intends to resolve a problem that a pressure sensing signal transferring part of a stylus in a known technology has a complex structure and relatively high costs, and provides a stylus and an electronic device assembly. The stylus includes a main circuit board, a pressure sensing module, and a first flexible printed circuit. The main circuit board includes a pressure sensing chip; the pressure sensing module includes a pressure strain collection element; one end of the first flexible printed circuit is electrically connected to the pressure strain collection element, and the other end of the first flexible printed circuit is electrically connected to the main circuit board for communication between the pressure sensing chip and the pressure strain collection element. The stylus may be further configured to transmit a first coded signal and a second coded signal. The second coded signal of a coding chip is transmitted by using a second flexible printed circuit. Beneficial effects of this application are as follows: The pressure sensing signal can be transmitted by using the flexible printed circuit, and a relatively high-cost rigid-flexible board does not need to be disposed. Therefore, overall costs of the stylus are relatively low.