Optical Information Reading Device with Dual Polarization Illumination

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Solution Overview

Problem

Existing optical information reading devices face challenges in reducing user installation load and achieving accurate code reading on various workpieces, particularly due to the need for adjusting installation angles and handling different surface types and code markings.

Innovation Solution

The device incorporates a dual illumination system with a first section using a polarization filter and a second section without, allowing the user to switch between modes based on the workpiece, thereby reducing the need for angle adjustments and optimizing reading accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a polarization filter is provided in the illumination optical system to reduce regular reflected light, then reading accuracy on planar surfaces is improved, but the ability to read codes on casting surfaces by direct part marking is disabled

Engineering Contradiction:

Improvereading accuracyVSAvoidcompatibility with different workpiece types

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The illumination optical system is segmented into multiple independent illumination units, each with its own polarization filter. This allows selective activation of polarization filtering for specific workpiece types, enabling the system to maintain both high reading accuracy on planar surfaces and compatibility with casting surfaces through direct part marking.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The polarization filter is made detachable, allowing dynamic reconfiguration of the illumination optical system. Users can attach the polarization filter when reading codes on planar surfaces and remove it when reading codes on casting surfaces, adapting the system behavior to match the specific workpiece requirements.

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If the optical axis is inclined to the normal line (oblique attachment) to reduce regular reflected light, then reading accuracy is improved, but image distortion occurs causing reading errors

Engineering Contradiction:

Improvereading accuracyVSAvoidimage accuracy

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The polarization filter is extracted from the illumination optical system and placed in the imaging optical system. This extraction allows the illumination optical system to maintain a parallel optical axis configuration for accurate imaging, while the polarization filtering function is preserved through the filter in the imaging path, eliminating image distortion.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The polarization filter acts as an intermediary element in the imaging optical system, mediating between the illumination light and the imaging element. This allows the system to benefit from polarization-based rejection of reflected light while maintaining a parallel optical axis configuration, thus avoiding image distortion.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If the polarization filter is made detachable to enable adaptation to different workpieces, then versatility is improved, but additional labor for detachment and attachment is required

Engineering Contradiction:

Improvecompatibility with different workpiece typesVSAvoidinstallation load

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The system incorporates an automatic polarization filter attachment mechanism that enables the polarization filter to attach and detach automatically based on the detected workpiece type or user selection, eliminating manual attachment labor while maintaining versatility for different workpiece types.

Inventive Principle:

Principle #25Self-service

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 approach reduces user labor and ensures accurate code reading across different workpieces by selectively using polarization and non-polarization modes, enhancing reading success rates and power efficiency.

Implementation Method 1

a first illumination section that illuminates a workpiece and irradiates the workpiece with illumination light through a polarization filter

Methodology Applied

Scientific EffectPolarization: Polarisation

Implementation Method 2

an imaging section provided with a polarization filter having a polarization direction different from a polarization direction of the polarization filter of the first illumination section, the imaging section for receiving light through the polarization filter

Methodology Applied

Scientific EffectPolarization: Polarisation

Data Source

PatentUS10747976B2Optical information reading device

Publication Date: 2020.08.18 KEYENCE CORP

AI summary

Provided is an optical information reading device that can reduce an installation load on a user, and can accurately read a code provided to each of various workpieces. A polarized illumination light source includes light emitters that irradiate the workpiece with illumination light through a polarization filter. A non-polarized illumination light source includes light emitters that irradiate the workpiece with illumination light without through a polarization filter. An imaging element is provided with a polarization filter having a polarization direction different from a polarization direction of the polarization filter of the light emitters. Either of the polarized illumination light source and the non-polarized illumination light source is used in accordance with the workpiece.