Specular Surface Measurement With Orthogonal Point-Source Diffusion

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Solution Overview

Problem

Existing measurement technologies, such as those used for inspecting painted vehicle surfaces, often lack sufficient accuracy due to difficulties in capturing specular reflection light from surfaces with varying normal directions and curvatures.

Innovation Solution

A measurement apparatus with an illumination unit comprising a plurality of point light sources arranged in orthogonal directions and diffusion plates with specific diffusion angles, ensuring a relationship of Ax < Ay, to enhance the accuracy of specular reflection light capture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional illumination methods are used for measuring painted surfaces, then the measurement can be performed, but the measurement accuracy is insufficient due to difficulty in capturing specular reflection light

Engineering Contradiction:
Improvemeasurement accuracyVSAvoiddifficulty in capturing specular reflection light
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The illumination unit is divided into multiple point light sources arranged in orthogonal directions, with each source contributing to different aspects of the illumination pattern. This segmentation allows precise control over the light distribution to capture specular reflection from surfaces with varying normal directions and curvatures

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the illumination pattern provide different quality characteristics - the orthogonal arrangement of point light sources creates localized illumination zones that adapt to local surface geometry, enabling accurate capture of specular reflection light from areas with different normal directions and curvatures

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If the diffusion angle Ax in the arrangement direction is increased to widen the measurable range, then more surfaces can be measured, but the brightness uniformity deteriorates

Engineering Contradiction:
Improvemeasurable rangeVSAvoidbrightness uniformity
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The diffusion plate is designed with asymmetric diffusion characteristics where the diffusion angle Ay in the orthogonal direction is larger than the diffusion angle Ax in the arrangement direction (Ay > Ax). This asymmetric design allows the illumination pattern to maintain brightness uniformity along the arrangement direction while achieving wide coverage in the orthogonal direction, thus widening the measurable range without sacrificing uniformity

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The diffusion plate is designed with asymmetric diffusion characteristics where the diffusion angle Ay in the orthogonal direction is larger than the diffusion angle Ax in the arrangement direction (Ay > Ax). This asymmetric design allows the illumination pattern to maintain brightness uniformity along the arrangement direction while achieving wide coverage in the orthogonal direction, thus widening the measurable range without sacrificing uniformity

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

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 apparatus achieves highly accurate measurement of painted surfaces by ensuring uniform brightness distribution and wide measurable range, enabling effective detection of defects like scratches and unevenness.

Implementation Method 1

a first diffusion plate 14, the light source 13 and the first diffusion plate 14 and the second diffusion plate 15 are arranged in parallel with each other

Methodology Applied
Scientific EffectLight diffusion: Scattering

Implementation Method 2

a light receiving unit configured to receive specular reflection light from the measurement target object illuminated by the illuminating unit

Methodology Applied
Scientific EffectSpecular reflection: Reflection

Data Source

PatentEP4610632A1Measurement apparatus and measurement method
Publication Date: 2025.09.03 RICOH CO LTD
  • EP4610632A1 patent drawingFigure 1
  • EP4610632A1 patent drawingFigure 2
  • EP4610632A1 patent drawingFigure 3A

AI summary

A measurement apparatus for measuring a measurement target object conveyed in a conveying direction, the measurement apparatus including an illuminating unit configured to illuminate the measurement target object; and a light receiving unit configured to receive specular reflection light from the measurement target object illuminated by the illuminating unit. The illuminating unit includes a light source and a first diffusion plate, the light source including a plurality of point light sources, a plurality of the light sources are arranged in a predetermined arrangement direction, the plurality of point light sources are arranged in an orthogonal direction that is orthogonal to the predetermined arrangement direction, and when a diffusion angle relative to the predetermined arrangement direction of the first diffusion plate is given as Ax and a diffusion angle relative to the orthogonal direction is given as Ay, a relationship of Ax &lt; Ay is satisfied.