Optical Information Reader Marker Light Alignment

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Solution Overview

Problem

Existing optical information readers face misalignment issues between the center of the marker light and the imaging area, particularly at closer distances, due to the separation requirements of light receiving sensors and marker light sources, which complicates size reduction and increases manufacturing costs.

Innovation Solution

The optical information reader positions the marker light irradiating unit farther away from the reading opening than the reflective mirror, with its optical axis parallel to the imaging area's optical axis, allowing the marker light to be close to the reflective mirror's edge, thereby reducing misalignment without hindering size reduction. This configuration eliminates the need for multiple marker optical systems, allowing for a more compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a light receiving sensor and marker light source are separated to reduce misalignment, then alignment accuracy between marker light center and imaging area center is improved, but device size increases and manufacturing cost increases

Engineering Contradiction:
Improvealignment accuracyVSAvoiddevice size
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent positions the marker light source in the lateral direction (X-axis) relative to the optical axis, rather than separating it axially. The marker light source is located at a position where its optical axis intersects the optical axis of the light receiving sensor, allowing both components to be compactly arranged without compromising alignment accuracy. This lateral positioning resolves the contradiction by achieving precise alignment without increasing device volume.

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

2Measurement precision

If multiple marker optical systems are provided on both sides of the light receiving sensor, then alignment accuracy is improved, but device complexity increases and manufacturing cost increases

Engineering Contradiction:
Improvealignment accuracyVSAvoidnumber of components
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the essential marker light source function from the complex dual-marker system. Instead of providing marker optical systems on both sides of the light receiving sensor, the invention uses a single marker light source positioned laterally, whose optical axis intersects with the sensor's optical axis. This simplified configuration achieves the same alignment accuracy without the complexity and cost of multiple marker systems.

Inventive Principle:
Principle #2Taking out (Extraction)

3Volume of moving object

If the marker light source is positioned close to the reading opening, then device size is reduced, but misalignment between marker light center and imaging area center increases

Engineering Contradiction:
Improvedevice sizeVSAvoidalignment accuracy
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent resolves this contradiction by changing the positional relationship from axial separation to lateral positioning. The marker light source is placed laterally offset from the optical axis, and its optical axis is oriented to intersect with the sensor's optical axis at the reading opening. This allows the marker light source to be positioned close to the reading opening for compactness while maintaining precise alignment through the intersecting optical axes configuration.

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

This solution effectively reduces misalignment between the marker light and imaging area centers, enabling size reduction of the optical information reader while maintaining accurate reading capabilities, and improves visibility by making the marker light brighter through a smaller spot diameter.

Implementation Method 1

a reflective mirror 24, an imaging lens 25

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

a reflective mirror 24, an imaging lens 25

Methodology Applied
Scientific EffectLens focusing: Lens

Data Source

PatentEP3139302B1Optical information reader
Publication Date: 2019.11.06 DENSO WAVE INC
  • EP3139302B1 patent drawingFigure 1
  • EP3139302B1 patent drawingFigure 2
  • EP3139302B1 patent drawingFigure 3

AI summary

An information code reader is provided to read an information code, such as a QR code (registered trademark). In this reader, a marker light irradiating unit (22) is provided in a position farther away from a reading opening (13) than a reflective mirror (24) is, and disposed such that an optical axis (Lgm) of a marker light (Lm) is parallel to an optical axis (Lgr) that is a center of an imaging area of a light receiving sensor (23) and the marker light (Lm) is close to (or in proximity to) an upper edge (outer edge) of the reflective mirror (24).