Optical Sensor Light Guide for Compact Phosphorescence Detection

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Solution Overview

Problem

Conventional apparatuses for detecting radiation light, such as phosphorescence, face challenges in miniaturization and simultaneously achieving a large light reception surface, and are unable to accurately distinguish between phosphorescent materials with different decay time constants, leading to difficulties in identifying the authenticity of security marks.

Innovation Solution

An optical sensor system utilizing a single light guide unit to guide excitation light to the detection target and radiation light to the photodetector, allowing for miniaturization while enlarging the light reception surface, and employing multiple detection times to determine the decay time constant of phosphorescent materials, thereby distinguishing between materials with different decay times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If conventional optical systems using lenses are used to detect radiation light, then the detection function is achieved, but the apparatus size cannot be miniaturized and the light reception area is limited by lens diameter

Engineering Contradiction:
Improvesensor sizeVSAvoidlight reception area
Core Design Contradiction:
Volume of moving objectVSArea of stationary object

Solution Approach 1:

A light guide is introduced as an intermediary component between the light source and the detection target, and between the detection target and the photodetector. The light guide transmits excitation light to the target and collects radiation light from the target, enabling compact sensor design while maintaining a large light reception area through the light guide's input surface

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The light guide serves multiple functions: it acts as both an excitation light transmission path and a radiation light collection path. This multi-functionality eliminates the need for separate optical components, enabling miniaturization while maintaining effective light reception

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

2Area of stationary object

If multiple photodetectors are arranged along the radiation light path to increase light reception area, then the light reception area is enlarged, but the device becomes complicated and large

Engineering Contradiction:
Improvelight reception areaVSAvoidsensor structure complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

Multiple detection functions are merged into a single photodetector by using a light guide to collect radiation light from a large area and concentrate it onto the photodetector's active surface. This eliminates the need for multiple photodetectors arranged along the light path, simplifying the device structure while maintaining a large effective light reception area

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If conventional detection methods are used, then radiation light detection is achieved, but the system cannot rapidly distinguish between phosphorescent materials with different decay time constants

Engineering Contradiction:
Improvedetection speedVSAvoiddecay time constant discrimination accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The light source is driven to emit excitation light in periodic pulses rather than continuously. By controlling the pulse width and repetition frequency, the system can excite phosphorescent materials and measure their decay characteristics at multiple time points, enabling rapid discrimination between materials with different decay time constants while maintaining high detection speed

Inventive Principle:
Principle #19Periodic action

4Measurement precision

If the light source is continuously irradiated to detect phosphorescence, then sufficient light signal is obtained, but the decay time constant cannot be accurately determined

Engineering Contradiction:
Improvedecay time constant measurement accuracyVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The continuous light source is replaced with periodic pulsed excitation. The pulse width is controlled to be shorter than the decay time constant of the phosphorescent material, allowing the excitation to be turned off during the measurement phase. This enables accurate measurement of the decay curve and determination of the decay time constant while reducing overall energy consumption compared to continuous irradiation

Inventive Principle:
Principle #19Periodic 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

The system effectively miniaturizes the sensor while enhancing the light reception area and enables rapid recognition of phosphorescence, accurately determining the authenticity of security marks by distinguishing between phosphorescent materials with different decay time constants.

Implementation Method 1

a light guide unit that guides excitation light from a light source to a detection target and that guides radiation light from the detection target to a photodetector

Methodology Applied
Scientific EffectLight guidance: Optical Fibre

Implementation Method 2

detecting radiation light such as phosphorescence emitted from a detection target excited by excitation light

Methodology Applied
Scientific EffectPhosphorescence: Phosphorescence

Implementation Method 3

radiation light such as phosphorescence emitted from a detection target excited by excitation light

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP3605067B1Optical sensor, light detecting device, paper sheet processing device, light detecting method, and phosphorescence detecting device
Publication Date: 2024.10.02 GLORY LTD
  • EP3605067B1 patent drawingFigure 1
  • EP3605067B1 patent drawingFigure 2
  • EP3605067B1 patent drawingFigure 3

AI summary

The objective of the present invention is to reduce the size of an optical sensor which detects radiated light such as phosphorescence radiated from a detection target excited by means of exciting light, and to increase a radiated light receiving surface of the optical sensor. An optical sensor (10) is configured to be provided with: a light source (30) which irradiates excitation light; a light detector (40) which detects radiation light emitted from a detection target (T) excited by the excitation light; and a single light guide unit (50) which guides the excitation light to the detection target T and guides the radiation light to the light detector (40).