Coaxial Illumination Scanner Eliminates Specular Reflections

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Solution Overview

Problem

Conventional optical scanners often suffer from inefficient illumination and issues with specular reflections, leading to energy loss and user discomfort due to peripheral illumination, which affects the accuracy and efficiency of barcode reading.

Innovation Solution

The optical slot scanner employs a coaxial illumination system where the light source and imaging camera are aligned closely and on-axis within a recessed compartment, ensuring that the illumination field overlaps with the imaging field of view and eliminating specular reflections by positioning the light source in close proximity to the camera, with the illumination axis being coaxial to the imaging axis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If peripheral illumination is used in conventional optical scanners, then the illumination field covers the imaging field of view, but specular reflections occur causing energy loss and user discomfort

Engineering Contradiction:

Improveillumination field coverageVSAvoidenergy loss from specular reflections

Core Design Contradiction:

Illumination intensityVSLoss of energy

Solution Approach 1:

The patent transitions from symmetric peripheral illumination to asymmetric coaxial illumination where the light source is positioned on the optical axis of the imaging camera. This asymmetric positioning eliminates the peripheral illumination that causes specular reflections while maintaining effective coverage of the imaging field of view through the coaxial configuration.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent converts the potentially harmful peripheral illumination that causes specular reflections into beneficial coaxial illumination. By positioning the light source on the optical axis, the system eliminates the harmful reflections while the illumination still effectively covers the imaging field, transforming a harmful configuration into a beneficial one.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Illumination intensity

If peripheral illumination is used, then the imaging field is covered, but user discomfort occurs due to reflections

Engineering Contradiction:

Improveillumination field coverageVSAvoiduser discomfort from reflections

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent uses asymmetric positioning of the light source on the optical axis rather than peripheral illumination. This asymmetric configuration eliminates the reflections that cause user discomfort while maintaining adequate illumination coverage through the coaxial arrangement of the light source and camera.

Inventive Principle:

Principle #4Asymmetry

3Use of energy by moving object

If coaxial illumination is implemented with light source close to camera, then illumination efficiency is enhanced and energy consumption reduced, but device complexity increases

Engineering Contradiction:

Improveenergy consumptionVSAvoidalignment precision required

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent merges the light source and imaging camera into a closely integrated coaxial configuration within a single housing. This merging reduces the overall system complexity by eliminating the need for separate illumination and imaging systems while achieving efficient energy use through the compact coaxial arrangement.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The coaxial configuration serves multiple functions simultaneously: it provides efficient illumination, enables precise alignment of optical axes, reduces energy consumption, and simplifies the overall device structure. The single integrated arrangement performs both illumination and imaging functions with shared optical components.

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

This configuration enhances illumination efficiency, reduces energy consumption, minimizes 'hot spots,' and prevents user discomfort by containing reflections within the scanner, resulting in improved image quality and accurate barcode reading.

Implementation Method 1

The light source defines an illumination field for illuminating indicia located on a target object

Methodology Applied

Scientific EffectLight emission: Light

Implementation Method 2

The imaging camera defines an imaging field of view for reading indicia located on a target object

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 3

eliminating specular reflections by positioning the light source in close proximity to the camera, with the illumination axis being coaxial to the imaging axis

Methodology Applied

Scientific EffectSpecular reflection: Reflection

Data Source

PatentUS8991707B2Optical slot scanner having coaxial illuminaton

Publication Date: 2015.03.31 SYMBOL TECHNOLOGIES LLC

AI summary

An optical slot scanner (10) and method includes a housing (12) supporting a scanning arrangement (22) within an interior region (14) of the housing. The scanning arrangement (22) includes an imaging camera (26) and light source (24) disposed within a recess compartment (80) located in the interior region of the housing. The imaging camera defines an imaging field (40) of view for reading indicia located on a target object. The light source defines an illumination field (42) for illuminating indicia located on a target object, such that the illumination field is substantially coaxial with the imaging field during a reading of indicia located on a target object.