Light Detection Device Fluorescence Phosphorescence Correction

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Solution Overview

Problem

Existing light detection devices cannot perform correction on both fluorescence and phosphorescence detecting portions due to the absence of a reference member for the phosphorescence detecting portion, as the excitation light does not reach its detection position.

Innovation Solution

A light detection device with a first detecting portion for fluorescence and a second detecting portion for afterglow, each equipped with a reference member emitting reference light that does not interfere with the detection, and a correction controller to adjust sensor gains based on the detected reference light, ensuring accurate detection of both fluorescent and phosphorescent information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a fluorescent reference plate is disposed at the detection position of the phosphorescence detecting portion, then correction can be performed on the fluorescence detecting portion, but the excitation light does not reach the detection position of the phosphorescence detecting portion so correction cannot be performed on the phosphorescence detecting portion

Engineering Contradiction:
Improvecorrection capabilityVSAvoiddetection accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent divides the reference plate into two separate segments: a first fluorescent reference plate for the fluorescence detecting portion and a second phosphorescent reference plate for the phosphorescence detecting portion. This segmentation allows each reference plate to be positioned and excited independently, enabling correction for both detecting portions without interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a light guide as an intermediary component to transfer excitation light from the excitation light source to the second phosphorescent reference plate. This light guide acts as a mediator that delivers the necessary excitation light to the phosphorescence detection area, enabling correction capability for the phosphorescence detecting portion.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the excitation light source illuminates the entire conveyor path, then both fluorescence and phosphorescence can be excited, but the excitation light interferes with the phosphorescence detection

Engineering Contradiction:
Improvedetection coverageVSAvoidlight interference
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the illumination strategy by using the excitation light source only for the fluorescence detecting area and introducing a separate light guide to provide excitation light to the phosphorescent reference plate. This segmentation prevents excitation light from directly interfering with the phosphorescence detection while still enabling excitation of phosphorescent materials.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses a light guide to pre-deliver excitation light to the second phosphorescent reference plate before the sheet reaches the detection position. This preliminary action ensures that the reference plate is properly excited and can provide accurate correction signals without interference from the main excitation light source during detection.

Inventive Principle:
Principle #10Preliminary action

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 accurate correction and detection of both fluorescence and phosphorescence, improving the reliability of the light detection device in identifying and classifying sheets based on printed information.

Implementation Method 1

The fluorescent material is excited by excitation light (e.g., ultraviolet rays) or the like emitted from an excitation light source. The excited fluorescent material emits light (fluorescence).

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 2

The phosphorescent material is excited by excitation light (e.g., ultraviolet rays) or the like emitted from an excitation light source. The excited phosphorescent material emits light.

Methodology Applied
Scientific EffectPhosphorescence: Phosphorescence

Data Source

PatentEP2290622B1Light detection device and sheet processing apparatus including the same
Publication Date: 2015.07.01 KK TOSHIBA
  • EP2290622B1 patent drawingFigure 1~2
  • EP2290622B1 patent drawingFigure 3
  • EP2290622B1 patent drawingFigure 4

AI summary

A light detection device comprising a first detecting portion 4 to detect fluorescence from a first detection position A on a conveyor path 115 along which a sheet P is conveyed; a second detecting portion 5 to detect afterglow from a second detection position B on the conveyor path 115 along which the sheet P is conveyed; a lighting portion 3 to apply excitation light over a range including the first detection position A and not including the second detection position B; a first reference member 10 to emit reference light toward the first detecting portion 4, the first reference member 10 including fluorescent material which emits fluorescence by being excited by the lighting portion 3; a second reference member 11 to emit reference light toward the second detecting portion 5 when the sheet P is present at the second detection position B, the reference light not influencing a result of detection by the second detecting portion 5; and a correction controller 9 to correct a result of detection by the first detecting portion 4 based on the reference light detected by the first detecting portion 4 and to correct a result of detection by the second detecting portion 5 based on the reference light detected by the second detecting portion 5.