3D Knob Touch Display Rotation Sensing with Multi-Finger Tracking

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Solution Overview

Problem

Existing three-dimensional input devices struggle with inaccurate determination of rotation operations due to variations in the number of fingers sensing and distance from the sensor during knob operations, leading to errors in rotation sensing.

Innovation Solution

An input display device with a capacitive touch panel and a sensing unit that measures electrostatic capacitance to determine rotation operations by considering the rotation amounts of all fingers touching the operation unit, updating rotation amounts when a finger is lost and reallocating them to remaining fingers, and resetting counts after determining a rotation operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional rotation sensing algorithms are used that determine rotation from single-finger circumferential movement, then the sensing algorithm is simple, but the rotation determination accuracy deteriorates when the number of sensed fingers varies

Engineering Contradiction:
Improverotation determination accuracyVSAvoidsensing algorithm complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the rotation sensing task by independently tracking each finger's rotation amount and then synthesizing the results. Each finger's rotation is calculated separately based on its circumferential movement on the knob, and then these individual measurements are combined to determine the overall rotation operation, improving accuracy without excessive complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges the rotation sensing capabilities of multiple fingers into a unified rotation determination system. By combining the rotation amounts from all sensed fingers and applying a threshold to the total, the system achieves more reliable rotation detection that is not dependent on any single finger's position or sensing stability

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If the system relies on continuous sensing of fingers during rotation operation, then rotation determination can be made, but the system becomes unstable when fingers are referred to or when distance from sensor varies

Engineering Contradiction:
Improverotation operation determination stabilityVSAvoidfinger position sensitivity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent applies beforehand cushioning by accumulating rotation amounts from multiple fingers and using a threshold value to confirm rotation operations. This accumulation buffer compensates for temporary sensing losses when fingers are referred to or move away from optimal sensing positions, maintaining stable operation determination

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The system continuously monitors the number of sensed fingers and their rotation amounts, providing feedback to adjust the rotation determination. When fingers are added or removed from sensing, the system adapts by redistributing rotation amounts among remaining fingers, ensuring continuous and stable rotation operation detection

Inventive Principle:
Principle #23Feedback

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

Stably determines rotation operations on three-dimensional operation units by continuously monitoring finger movements and adjusting for changes in the number of sensed fingers, enhancing accuracy and reducing errors.

Implementation Method 1

a capacitive touch panel attached to the display and including at least one three-dimensional operation unit on a front face of the touch panel, and a sensing unit configured to measure an electrostatic capacitance of the touch panel

Methodology Applied
Scientific EffectElectrostatic capacitance: Capacitance

Data Source

PatentEP4394564B1Input display device
Publication Date: 2026.04.22 ALPS ALPINE CO LTD
  • EP4394564B1 patent drawingFigure 1A~1C
  • EP4394564B1 patent drawingFigure 2A~4
  • EP4394564B1 patent drawingFigure 5A~5C

AI summary

Provided is an input display device (100) capable of improving determination accuracy of a rotation operation on a three-dimensional operation unit. An input display device (100) of the present invention includes a display (110) configured to display an image, a capacitive touch panel (120) attached to the display (110) and including a knob (130) that is at least one three-dimensional operation unit on the front face, and a sensing unit (150) configured to measure an electrostatic capacitance of the touch panel (120) and senses an operation on the touch panel (120) based on the measured electrostatic capacitance. The sensing unit (150) senses the rotation amounts of all the fingers touching the knob (130), and determines that the rotation operation on knob (130) has been performed when a sensed rotation amount of any of the fingers reaches a threshold value.