Adjustable Irradiance Illuminant with Reflected Light Feedback

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Solution Overview

Problem

Machine vision applications face challenges in maintaining constant radiant power from light sources, particularly LEDs, due to fluctuations caused by aging, temperature changes, and contamination, which affect irradiance and overall system performance.

Innovation Solution

An arrangement with an optical cover that detects the intensity of reflected light and adjusts the radiant power of the light source using a control unit, ensuring consistent irradiance by regulating the electric current or power based on reflection intensity, without the need for additional sensors on the light source side, and incorporating temperature sensors to account for ambient temperature influences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If LEDs are used as light sources in machine vision applications, then energy efficiency and lifespan are improved, but radiant power fluctuates due to aging and temperature changes

Engineering Contradiction:
Improveenergy efficiencyVSAvoidradiant power stability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent implements a feedback control system where a light sensor detects the intensity of reflected light from the optical cover, and a control unit adjusts the radiant power of the LED light source based on this detection to maintain constant irradiance in the luminous area, thereby compensating for fluctuations caused by aging and temperature changes

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically changes the operating parameters of the LED light source by adjusting the control variable (electric current or power) based on detected reflected light intensity and temperature sensor readings, allowing the radiant power to be regulated in response to environmental conditions and aging effects

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If the radiant power is increased to compensate for contamination, then illuminance is maintained, but energy consumption increases

Engineering Contradiction:
ImproveilluminanceVSAvoidenergy consumption
Core Design Contradiction:
Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The feedback control system continuously monitors the reflected light intensity and adjusts the radiant power only to the extent necessary to maintain constant illuminance in the luminous area, preventing excessive energy consumption while compensating for contamination effects on the optical cover

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system applies partial action by regulating radiant power based on actual contamination levels detected through reflected light intensity, rather than continuously operating at maximum power to ensure illuminance, thus avoiding excessive energy consumption

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If a light sensor is placed on the light source side to detect reflected light, then irradiance control is achieved, but the light source area is occupied and shadows are cast

Engineering Contradiction:
Improveirradiance controlVSAvoidlight source area
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The light sensor is extracted from the light source side and relocated to detect reflected light from the optical cover, separating the measurement function from the illumination function to avoid occupying light source area and casting shadows on the luminous area

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The optical cover serves as an intermediary element that enables indirect measurement - the light sensor detects reflected light from the optical cover surface, which provides information about the radiant power reaching the luminous area without requiring direct placement near the light source

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution maintains precise control over irradiance in machine vision applications, reducing the impact of fluctuations and contamination, thereby enhancing the reliability and accuracy of automated image processing.

Implementation Method 1

a reflection part of the incident light is reflected in the optical cover

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

an intensity of the reflection part being detected

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 3

LEDs are gradually becoming state-of-the-art as a light source in lamps

Methodology Applied
Scientific EffectLight Emitting Diode: Light Emitting Diode

Data Source

PatentEP3244699B1Illuminant with adjustable irradiance
Publication Date: 2020.09.23 B&R IND AUTOMATION GMBH
  • EP3244699B1 patent drawingFigure 1~2
  • EP3244699B1 patent drawingFigure 3~5

AI summary

To specify a light source for a machine vision application whose resulting irradiance (P') in a lighting area (5) at a working distance (d) can be adjusted as precisely as possible, an optical cover (2) of the light source (1) is provided, which is designed such that a transmission part (t2) of the incident light (L) passes through the optical cover (2) (1) and a reflection part (r2) of the incident light (L) is reflected in the optical cover (2), wherein a light sensor (3) is provided that detects the intensity (Ir2) of the reflection part (r2) in the optical cover (2). Furthermore, a method is specified according to which the intensity (Ir2) of the reflection part (r2) is detected and, based on the intensity (Ir2), the radiant power (P) of the light source (1) is controlled in order to adjust the irradiance (P') of the transmission part (t2).