Infrared Touch Screen Phase Management for Ambient Light Interference

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Solution Overview

Problem

Infrared touch screens face precision issues due to light interference from ambient light changes, particularly sunlight, which affects the detection accuracy.

Innovation Solution

The implementation of a phase managing mechanism in an infrared touch screen that alternates phases based on ambient light intensity, adjusting the roles of infrared emitters and receivers between edges to maintain optimal detection precision by switching between different scanning configurations in response to changing light conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If infrared emitters and receivers continuously scan the touch detecting region, then the response speed is improved, but the detection precision deteriorates due to light interference from ambient light changes

Engineering Contradiction:
Improveresponse speedVSAvoiddetection precision
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent implements periodic action by dividing the scanning operation into alternating phases (first phase and second phase). In the first phase, infrared emitters on the first edge and receivers on the second edge scan the touch detecting region. In the second phase, the roles are reversed with receivers on the first edge and emitters on the second edge scanning. This periodic alternation allows the system to maintain continuous scanning capability while periodically switching configurations to resist ambient light interference, thereby preserving both response speed and detection precision.

Inventive Principle:
Principle #19Periodic action

2Device complexity

If the infrared touch screen uses a fixed scanning configuration, then the device complexity is reduced, but the adaptability to varying ambient light conditions deteriorates

Engineering Contradiction:
Improvedevice complexityVSAvoidadaptability to ambient light
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by making the scanning configuration changeable rather than fixed. The phase managing mechanism dynamically switches between the first phase configuration (emitters on first edge, receivers on second edge) and the second phase configuration (receivers on first edge, emitters on second edge). This dynamic switching capability enables the infrared touch screen to adapt to varying ambient light conditions without significantly increasing device complexity, as the same hardware components are reused in different configurations.

Inventive Principle:
Principle #15Dynamics

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

Effectively reduces or eliminates light interference, enhancing the detection precision and accuracy of the infrared touch screen by dynamically adapting to varying ambient light conditions.

Implementation Method 1

there are infrared emitters and infrared receivers fixed on the first edge, and there are infrared emitters and infrared receivers fixed on the second edge

Methodology Applied
Scientific EffectInfrared emission: Infrared Radiation

Implementation Method 2

a phase managing mechanism, configured to control the phase alternation in said infrared touch screen which has a plurality of phases containing at least a first phase and a second phase

Methodology Applied
Scientific EffectPhase alternation control: Phase Modulation

Data Source

PatentEP2515216B1Infrared touch screen
Publication Date: 2019.06.05 BEIJING IRTOUCH SYST CO LTD
  • EP2515216B1 patent drawingFigure 1
  • EP2515216B1 patent drawingFigure 2
  • EP2515216B1 patent drawingFigure 3

AI summary

This invention provides an infrared touch screen, comprising: a touch detecting region; a plurality of edges containing at least to first edge and a second edge, wherein the first, edge and the second edge are opposite to each other, there are infrared emitters and infrared receivers fixed on the first edge and there are infrared emitters and infrared receivers fixed of the second edge; and a phase managing mechanism configured to control the phase alternation of the infrared touch screen which has a plurality of phases containing at least a first phase and a second phase. With the structure change and phase managing mechanism application in this infrared touch screen, the light interference caused by varying ambient light can be reduced or eliminated effectively.