Foldable Touchscreen Hinge Angle Sensing Without Hall Sensors

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Solution Overview

Problem

Foldable displays require additional components like hall sensors to detect the folding angle, leading to increased power consumption and manufacturing costs.

Innovation Solution

Determine the folding angle of a flexible touchscreen based on self-capacitances sensed by the touchscreen without additional electronic components, using a self-sensing scan to analyze touch sensing data and convert it to the strength domain for angle calculation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If hall sensors are added to detect folding angle, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvefolding angle detection accuracyVSAvoidnumber of additional components
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The flexible touchscreen serves itself to detect folding angle by monitoring changes in its own self-capacitance values across different folding regions, eliminating the need for external hall sensors or additional detection components

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The self-capacitance sensing mechanism, originally designed for touch detection, is extended to simultaneously perform folding angle detection, allowing one component to fulfill multiple functions

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

2Measurement precision

If hall sensors are added to detect folding angle, then measurement precision is improved, but use of energy increases

Engineering Contradiction:
Improvefolding angle detection accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system uses the existing self-capacitance sensing circuitry to detect folding angle, avoiding the need for separate powered sensors like hall sensors that would consume additional energy

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The folding angle detection function is merged with the existing touch sensing mechanism by analyzing self-capacitance variations, consolidating detection functions into a single low-power system

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If hall sensors are added to detect folding angle, then measurement precision is improved, but manufacturing cost increases

Engineering Contradiction:
Improvefolding angle detection accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The flexible touchscreen utilizes its inherent self-capacitance properties for folding angle detection, eliminating the need to manufacture and assemble additional hall sensor components

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The folding angle detection capability is extracted from the touch sensing data itself by analyzing self-capacitance patterns, removing the need for separate detection hardware

Inventive Principle:
Principle #2Taking out (Extraction)

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

Accurately determines the folding angle of a flexible touchscreen without additional components, reducing power consumption and manufacturing costs while maintaining functionality.

Implementation Method 1

detecting, by a touchscreen controller, self-capacitances sensed in a folding area of the flexible touchscreen using a self-sensing scan

Methodology Applied
Scientific EffectSelf-capacitance sensing: Capacitance

Data Source

PatentEP4216043B1Open close detection of foldable phone lid angle calculation
Publication Date: 2025.12.03 STMICROELECTRONICS ASIA PACIFIC PTE
  • EP4216043B1 patent drawingFigure 1A~1C
  • EP4216043B1 patent drawingFigure 1D~1E
  • EP4216043B1 patent drawingFigure 1F

AI summary

A method for operating an electronic device includes rotating a first portion of a flexible touchscreen with respect to a second portion of the flexible touchscreen around a folding axis; detecting, self-capacitances sensed in a folding area of the flexible touchscreen using a self-sensing scan, where a first side of the folding area is on the first portion of the flexible touchscreen and a second side of the folding area is on the second portion of the flexible touchscreen, and the first side and the second side are separated by a folding axis; determining, a current strength sensed by the flexible touchscreen in the folding area based on the self-capacitances in the folding area; and determining, a folding angle of the first portion of the flexible touchscreen with the second portion of the flexible touchscreen around the folding axis based on the current strength in the folding area.