Light Curtain Housing With Integrated Indicator Lamp Visibility

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Solution Overview

Problem

Light curtains with metal housings face challenges in maintaining high visibility of indicator lamps while preserving rigidity, especially when exposed to harsh environments or when bumper portions are present, leading to restricted visibility and potential interference with optical axes.

Innovation Solution

The design incorporates an indicator lamp disposed along the longitudinal direction of the housing, using a translucent front cover and a light diffusing member made of transparent resin with added fine particles, and integrates the bumper portion with the indicator lamp function to ensure high visibility without compromising rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the indicator lamp is disposed on the outer surface of the extruded metal case, then the visibility of the indicator lamp is improved, but additional processing is required and the arrangement position is restricted by the extruded shape

Engineering Contradiction:
Improvevisibility of indicator lampVSAvoidadditional processing and arrangement restriction
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The indicator lamp housing is merged with the front cover of the light curtain housing, forming an integrated structure. The indicator lamp is disposed on the outer surface of the front cover, which is part of the extruded metal case, but the integration eliminates the need for separate indicator lamp housings and reduces arrangement restrictions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The front cover serves multiple functions: it protects the detection window, provides mounting for the indicator lamp, and maintains the structural integrity of the housing. This multi-functionality reduces the need for additional components and processing steps.

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

2Device complexity

If the indicator lamp is incorporated in the detection window of the optical axis, then the arrangement is simplified, but the visibility of the indicator lamp is impaired and it may interfere with the optical axis

Engineering Contradiction:
Improvearrangement simplicityVSAvoidvisibility of indicator lamp
Core Design Contradiction:
Device complexityVSIllumination intensity

Solution Approach 1:

The indicator lamp is moved from the detection window area to the outer surface of the front cover, changing its spatial dimension. This relocation allows the indicator lamp to be visible from the side without interfering with the optical axis that passes through the detection window.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If a bumper portion is provided to protect the detection window, then the robustness of the light curtain is improved, but the visibility of the indicator lamp is further restricted

Engineering Contradiction:
Improverobustness of light curtainVSAvoidvisibility of indicator lamp
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The front cover is segmented into different functional areas: the detection window area for optical detection and the outer surface area for indicator lamp display. The bumper portion protects the detection window area while the indicator lamp is disposed on the outer surface, allowing both functions to coexist without interfering with each other.

Inventive Principle:
Principle #1Segmentation

4Strength

If an extruded metal case is used for the housing, then the rigidity of the housing is improved, but the arrangement position of the indicator lamp is restricted by the extruded shape

Engineering Contradiction:
Improverigidity of housingVSAvoidarrangement restriction of indicator lamp
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The indicator lamp housing is merged with the front cover of the extruded metal case, allowing the indicator lamp to be disposed on the outer surface of the extruded structure without requiring modifications to the basic extruded shape. This integration maintains the rigidity benefits of the extruded metal case while providing flexibility for indicator lamp placement.

Inventive Principle:
Principle #5Merging (Combining)

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

The solution allows for clear visual indication of operation states and instructions without impairing the structural integrity of the light curtain, even in harsh conditions, and reduces interference with optical axis detection.

Implementation Method 1

a light diffusing member made of transparent resin with added fine particles

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP4339654B1Light curtain
Publication Date: 2025.11.05 KEYENCE CORP
  • EP4339654B1 patent drawingFigure 1
  • EP4339654B1 patent drawingFigure 2
  • EP4339654B1 patent drawingFigure 3

AI summary

Display with high visibility without impairing rigidity of a housing is performed. A light curtain includes: a housing in which one element (for example, a light projecting element) of a pair of a light projecting element and a light receiving element forming a plurality of optical axes is disposed inside along a longitudinal direction in order to form the plurality of optical axes at intervals, the housing including a metal case extending in the longitudinal direction and end members connected to both ends of the metal case; a cover that transmits light from the light projecting element and is attached to the housing so as to cross the plurality of optical axes; an indicator lamp that is a light diffusing member disposed outside an outer surface of at least one of the cover and the housing along the longitudinal direction or formed in series with the cover; and an indicator lamp light source (not illustrated) that is accommodated in the housing and supplies light for displaying toward the indicator lamp.