Multi-source Transillumination for Translucent Product Inspection

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Solution Overview

Problem

Existing devices for contactless detection of translucent products at high conveying speeds suffer from insufficient light intensity and limited illumination area, leading to incomplete inspection of products.

Innovation Solution

The use of at least two independent light sources, one positioned in front of and one behind the receiving unit, with shading elements to shield scattered light and ensure complete illumination of the product across its width, increasing light intensity and area coverage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single light source is used, then the device complexity is reduced, but the light intensity and illumination area become insufficient for high-speed inspection

Engineering Contradiction:
Improvenumber of light sourcesVSAvoidlight intensity
Core Design Contradiction:
Device complexityVSIllumination intensity

Solution Approach 1:

The illumination system is segmented into multiple independent light sources positioned at different locations (front and rear of the receiving unit) to provide comprehensive coverage. Each light source independently illuminates different portions of the product, ensuring complete transillumination during high-speed conveyance.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If a single light source is used, then the device structure is simplified, but the illumination area coverage becomes incomplete

Engineering Contradiction:
Improvearrangement of light sourcesVSAvoidillumination area
Core Design Contradiction:
Device complexityVSArea of stationary object

Solution Approach 1:

The illumination system transitions from a single-point source to a multi-dimensional arrangement with light sources positioned both in front of and behind the receiving unit. This spatial distribution across different dimensions ensures that the entire product width and length are illuminated during conveyance.

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

3Device complexity

If light sources are positioned close to the receiving unit, then the device compactness is improved, but scattered light from lenses impairs the image quality

Engineering Contradiction:
Improvedevice compactnessVSAvoidimage quality
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The harmful scattered light is extracted and separated from the useful illumination path by positioning light sources at strategic distances and using shading elements. This removes the interfering light components while preserving the beneficial transillumination effect on the product.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Shading elements are introduced as intermediary components between the light sources and the receiving unit. These elements selectively block scattered light from lenses that would impair image quality, while allowing the useful illumination to pass through and illuminate the product effectively.

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 configuration ensures reliable and comprehensive illumination of translucent products, preventing partial areas from being missed and enhancing transillumination, thereby enabling effective detection of characteristics at high speeds.

Implementation Method 1

a transmission unit with a light source for generating high-intensity light radiation

Methodology Applied
Scientific EffectLight radiation: Light

Implementation Method 2

a light shaping element for forming a flat light field from the light radiation

Methodology Applied
Scientific EffectLight field formation: Lens

Implementation Method 3

a focusing element for forming a light beam transverse to the conveying direction F from the planar light field

Methodology Applied
Scientific EffectFocusing: Focusing

Implementation Method 4

a receiving unit with a detection means for recording the light radiation transflected by the product

Methodology Applied
Scientific EffectTransflection: Reflection

Implementation Method 5

The light radiation scattered and/or reflected within the translucent product is recorded and evaluated by the detection means

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP2252880B1Apparatus and method for the contactless detection of characteristics of continuously conveyed, translucent products
Publication Date: 2018.11.28 NORDISCHER MASCHINENBAU RUD BAADER GMBH CO KG
  • EP2252880B1 patent drawingFigure 1
  • EP2252880B1 patent drawingFigure 2
  • EP2252880B1 patent drawingFigure 3

AI summary

The invention relates to a device (10) for the detection of characteristics of continuously delivered translucent products (15), comprising a transmission unit (11, 12) having a light source (16, 17) for generating high-intensity light radiation, a light shaping element (18, 19) for forming a planar light field from the light radiation, and a focusing element (20, 21) for forming a line of light from the planar light field extending transversely to the delivery direction F of the products (15), and a receiving unit (13) having a detection means (22) for accommodating light radiation transflected from the product (15), a shading element (23, 24) being disposed between the transmission unit (11, 12) and the receiving unit (13), characterized in that at least two transmission units (11, 12) are provided with a corresponding design such that at least two independent light sources (16, 17) are provided for illuminating the product (15), wherein a transmission unit (12) is disposed in the delivery direction F of the products (15) in front of the receiving unit (13), and the other transmission unit (11) is disposed in the delivery direction F behind the receiving unit (13). The invention further relates to a corresponding method.