Dual Illumination Information Code Reader for Screen and Cover Decoding

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Solution Overview

Problem

Information code readers face challenges in decoding codes covered with materials that transmit infrared light but not visible light, especially in bright outdoor environments, and struggle to read codes displayed on liquid crystal screens due to the use of visible light filters that prevent imaging.

Innovation Solution

The information code reader employs a dual illumination system with visible light and infrared light sources, along with a filter that transmits infrared light without visible light, allowing for the decoding of codes covered with infrared-transmitting materials and those displayed on screens by capturing images with separate image acquisition units for each light band.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a filter that transmits infrared light without visible light is used, then codes covered with infrared-transmitting materials can be read, but codes displayed on liquid crystal screens cannot be imaged

Engineering Contradiction:
Improvereading reliabilityVSAvoidimaging adaptability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent divides the imaging system into two separate image acquisition units: one optimized for visible light and another for infrared light. This segmentation allows each unit to be specialized for its respective wavelength band, enabling the system to read both infrared-transmitting codes and liquid crystal screen displays without interference from the other light sources

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a multi-functional imaging system where the first image acquisition unit handles visible light imaging (for LCD screens) and the second image acquisition unit handles infrared light imaging (for infrared-transmitting codes). By combining these two specialized units, the system achieves universal capability to handle both types of codes that would be mutually exclusive in a single-filtered system

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

2Ease of operation

If visible light is used for imaging, then liquid crystal screen codes can be read, but infrared-transmitting material codes cannot be decoded in bright outdoor environments

Engineering Contradiction:
Improveimaging easeVSAvoiddecoding reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent segments the illumination and imaging functions into two independent channels: visible light illumination with visible light imaging for LCD screens, and infrared light illumination with infrared light imaging for infrared-transmitting codes. This segmentation eliminates the interference problem where ambient visible light overwhelms the infrared signal from infrared-transmitting materials

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an infrared light source as an intermediary illumination medium to enable imaging of infrared-transmitting codes. The infrared light penetrates the infrared-transmitting material and reflects off the code, allowing the infrared-sensitive image acquisition unit to capture the code information without being affected by ambient visible light conditions

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If a single image acquisition unit with a filter is used, then device complexity is reduced, but processing load increases and decoding accuracy decreases

Engineering Contradiction:
Improvedevice complexityVSAvoiddecoding productivity
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent segments the imaging function into two dedicated image acquisition units, each optimized for a specific wavelength band. This segmentation actually reduces processing complexity by eliminating the need for complex signal separation algorithms that would be required if a single unit tried to handle both visible and infrared light simultaneously

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts the infrared imaging function from the visible light imaging function by using separate image acquisition units. This extraction simplifies the processing pipeline by allowing each unit to process only its designated wavelength band independently, improving decoding productivity and accuracy without increasing overall device complexity

Inventive Principle:
Principle #2Taking out (Extraction)

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 enables the readable capture and decoding of information codes covered with infrared-transmitting materials and those displayed on screens, even in bright outdoor conditions, by separating the imaging and decoding processes for visible and infrared light bands, reducing processing load and improving decoding accuracy.

Implementation Method 1

a filter that transmits light in the second wavelength band without transmitting visible light

Methodology Applied
Scientific EffectOptical filtering: Filter (optical)

Implementation Method 2

a first illumination unit capable of radiating visible light

Methodology Applied
Scientific EffectVisible light emission: Light

Implementation Method 3

a second illumination unit capable of radiating light in a predetermined second wavelength band different from the visible light wavelength band

Methodology Applied
Scientific EffectInfrared light emission: Infrared Radiation

Implementation Method 4

a first image acquisition unit that captures an information code in a state where visible light is radiated by the first illumination unit

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 5

a second image acquisition unit that captures an information code while the second illumination unit radiates light in the second wavelength band

Methodology Applied
Scientific EffectInfrared light reflection: Reflection

Data Source

PatentEP3872681B1Information-code reading device
Publication Date: 2024.02.14 DENSO WAVE INC
  • EP3872681B1 patent drawingFigure 1
  • EP3872681B1 patent drawingFigure 2
  • EP3872681B1 patent drawingFigure 3

AI summary

There is provided an information code reader capable of readably imaging an information code displayed on a screen, not liming to an information code covered by a cover portion through which visible light cannot be transmitted. In this information code reader, first illumination units (21a to 24a) radiate visible light, in which an information code is subjected to image acquisition by a first image acquisition unit (25a). Second illumination units (21b to 24b) radiate infrared light, in which the information code is subjected to image acquisition by a second image acquisition unit (25b). A visible light cut filter (29), which does not allow the visible light to pass through, but which allows the infrared light pass through, is arranged depending on a spatial imaging range provided by the second image acquisition unit (25b).