Pivotable Tunnel Reflector for Line Scan Camera Illumination

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Solution Overview

Problem

Existing line camera illumination systems face challenges in achieving high contrast images when dealing with glossy or reflective substrates, as bright field lighting can be impaired by direct light reflection, necessitating a switch to dark field illumination to avoid this issue.

Innovation Solution

A tunable illumination system featuring a reflector in the form of a tunnel with a diffusely scattering inner surface that can pivot between bright field and dark field configurations, allowing for adaptable lighting by altering the orientation of its absorptive surface to control light direction and minimize direct reflection onto the camera.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If bright field lighting is used to illuminate the observation field, then uniform illumination is achieved, but direct light reflection from glossy or reflective areas impairs image contrast

Engineering Contradiction:
Improveuniform illuminationVSAvoiddirect light reflection
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The reflector is designed with a pivotable section that can be rotated between a first position for bright field illumination and a second position for dark field illumination. This dynamic reconfiguration allows the system to adapt its illumination mode based on the substrate characteristics, resolving the contradiction between uniform illumination and direct reflection interference.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the illumination parameters by rotating the reflector section, which alters the light path geometry. In the first position, light is directed uniformly onto the observation field; in the second position, the light path is modified to prevent direct reflection into the camera, thus changing the illumination mode to resolve the contradiction.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If dark field illumination is used to avoid direct light reflection, then image contrast is improved, but light output is reduced

Engineering Contradiction:
Improvedirect light reflectionVSAvoidlight output
Core Design Contradiction:
Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The reflector is divided into a stationary section and a pivotable section with different surface properties. The pivotable section can be positioned to either block direct reflection paths (dark field mode) or allow diffuse reflection (bright field mode). This local differentiation of reflector functionality enables the system to maintain adequate light output while preventing direct reflection when in dark field mode.

Inventive Principle:
Principle #3Local quality

3Device complexity

If a fixed illumination system is used, then device complexity is reduced, but adaptability to different applications is limited

Engineering Contradiction:
Improvesystem structureVSAvoidillumination mode adaptability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The reflector incorporates a pivotable section that can be rotated between two positions, enabling the system to switch between bright field and dark field illumination modes. This dynamic element adds minimal complexity while significantly enhancing adaptability to different substrate types and inspection requirements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The single reflector structure serves multiple functions by being configurable in two positions: it can provide uniform illumination for matte surfaces (bright field mode) or prevent direct reflection for glossy surfaces (dark field mode). This multi-functionality within a single device structure resolves the contradiction between simplicity and adaptability.

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

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

Enables easy adaptation between bright field and dark field lighting modes, ensuring high contrast images are captured by diffusely scattering light uniformly in bright field configurations and effectively blocking reflective areas in dark field configurations, maintaining high light output and image quality.

Implementation Method 1

a reflector (10) in the form of a tunnel, which has an inner surface that diffusely scatters the light

Methodology Applied
Scientific EffectDiffuse scattering: Scattering

Implementation Method 2

the second part of the reflector is pivoted to the position where the light-absorbing surface faces the interior of the tunnel

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentEP2843396B1Illumination system for a line scan camera
Publication Date: 2016.03.02 BST ELTROMAT INT LEOPOLDSHOHE
  • EP2843396B1 patent drawingFigure 1~2

AI summary

Illumination system for a line scan camera (24), with a reflector (10) in the form of a tunnel, which has an inner surface (16, 18) that diffusely scatters the light and directs the light from a light source (14) onto a line-shaped observation field (20) which is visible from the line scan camera (24) through a light exit slot (22) of the reflector, characterized in that the light exit slot (22) divides the reflector into a stationary part (30) and a pivotable part (32) which has a light-absorbing surface (42) and can be pivoted about an axis (34) extending in the longitudinal direction of the observation field (20) into a position in which the light-absorbing surface (42) faces the interior of the tunnel.