Optical switch and control method thereof

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Solution Overview

Problem

Optical switches in field devices face a trade-off between responsiveness and the lifespan of light emitting elements, where increasing emission frequency improves responsiveness but reduces the lifespan of the light emitting element, leading to increased maintenance and costs.

Innovation Solution

An optical switch configuration with a controller that adjusts the emission frequency of the light emitter based on operation panel usage, setting it to a higher frequency when the panel is operated and a lower frequency when not, to balance responsiveness and lifespan, using a drive waveform generator to output rectangular-shaped pulse signals and a frequency setter to manage emission frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the emission frequency of the light emitter is increased, then the responsiveness of the optical switch is improved, but the lifespan of the light emitting element is decreased

Engineering Contradiction:
ImproveresponsivenessVSAvoidlifespan of light emitting element
Core Design Contradiction:
SpeedVSDuration of action of stationary object

Solution Approach 1:

The optical switch dynamically adjusts the emission frequency of the light emitter based on the operational state of the operation panel. When the panel is being operated, the emission frequency is increased to high frequency for fast response. When the panel is not being operated, the emission frequency is reduced to low frequency to extend the lifespan of the light emitting element. This dynamic adaptation resolves the contradiction between responsiveness and lifespan.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the operational parameter (emission frequency) of the light emitter based on the detected state of the operation panel. The controller switches between high frequency and low frequency modes, thereby adjusting the parameter to optimize both responsiveness during operation and lifespan during idle periods, resolving the technical contradiction.

Inventive Principle:
Principle #35Parameter changes

2Speed

If the emission frequency of the light emitter is increased, then the responsiveness is improved, but the maintenance frequency is increased and costs are increased

Engineering Contradiction:
ImproveresponsivenessVSAvoidmaintenance frequency
Core Design Contradiction:
SpeedVSEase of repair

Solution Approach 1:

The system dynamically adjusts emission frequency based on operational need. During active operation, high frequency provides fast response. During idle periods, low frequency reduces wear on the light emitting element, thereby reducing maintenance frequency and associated costs, while maintaining responsiveness when needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

By changing the emission frequency parameter based on operational state, the system achieves fast response during operation while reducing overall usage intensity during idle periods, thereby extending component life and reducing maintenance requirements and costs.

Inventive Principle:
Principle #35Parameter changes

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 configuration extends the lifespan of the light emitting element while maintaining improved responsiveness by dynamically adjusting emission frequencies based on panel usage and detecting potential abnormalities like foreign substance adhesion.

Implementation Method 1

The optical switch emits light (infrared light or visible light) from the light emitter to the glass plate at a certain frequency (for example, several tens of hertz). The optical switch determines whether the operation panel (switch) is operated or not by determining whether the light receiver receives the reflected light or not.

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2955850B1Optical switch and control method thereof
Publication Date: 2021.06.23 YOKOGAWA ELECTRIC CORP
  • EP2955850B1 patent drawingFigure 1
  • EP2955850B1 patent drawingFigure 2
  • EP2955850B1 patent drawingFigure 3

AI summary

An optical switch includes a light receiver (22) configured to receive a pulsed light (L2) transmitted from an operation panel (10) operated by a user, the light receiver (22) being configured to generate a light receiving signal (R) in response to receipt of the pulsed light (L2), and a controller (30) configured to receive the light receiving signal (R) from the light receiver (22), the controller being configured to generate, in accordance with the light receiving signal (R), a controlling signal (C) for controlling a frequency of a pulsed light (L1) to be emitted toward the operation panel (10).