Linear Light Source UV-Visible LED Crosstalk Mitigation

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Solution Overview

Problem

The existing automatic transaction apparatuses face issues with ultraviolet light LEDs causing unwanted excitation of visible light LEDs, leading to unnecessary light emission due to lattice imperfections or impurities, which affects the accuracy of bank note differentiation.

Innovation Solution

A linear light source design that includes ultraviolet and visible light LEDs disposed at least at one end of an optical axis with a level difference, and a cross-sectional T-shaped heat sink with a convex part on a metal flat plate to shield ultraviolet rays from reaching the visible light LEDs, preventing excitation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If ultraviolet light LED and visible light LED are adjacently arranged without level difference, then device complexity is reduced, but ultraviolet light excites visible light LED causing measurement precision degradation

Engineering Contradiction:

Improvestructure complexityVSAvoiddetection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces a vertical dimension (level difference) to the arrangement of UV and visible light LEDs. Instead of only horizontal adjacency, the UV LED is positioned at a different vertical level, causing its optical axis to be shifted relative to the visible light LED. This dimensional change prevents UV light from directly exciting the visible light LED while maintaining horizontal compactness.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent introduces a light shielding member (intermediary element) positioned between the UV LED and visible light LED. This intermediary component blocks the harmful UV light from reaching the visible light LED, preventing unwanted excitation and fluorescence while allowing both LEDs to function in their intended positions.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Illumination intensity

If ultraviolet light LED irradiates visible light LED, then light intensity is increased, but unnecessary light emission occurs due to fluorescence

Engineering Contradiction:

Improvelight intensityVSAvoidfluorescent emission

Core Design Contradiction:

Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts or removes the harmful interaction between UV and visible light LEDs by introducing a light shielding member. This member selectively blocks UV light from reaching the visible light LED, preventing the fluorescence effect while maintaining the intended light emission functions of both LEDs independently.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the potentially harmful UV irradiation effect into a beneficial spatial separation solution. By positioning the UV LED at a different level and using shielding, the design ensures that UV light only performs its intended function (illuminating the object from above) without causing harmful fluorescence in the visible light LED, thus separating the functions cleanly.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 design effectively reduces the influence of ultraviolet light on visible light LEDs, minimizing unnecessary light emission and improving the accuracy of bank note differentiation in automatic transaction systems.

Implementation Method 1

since lattice imperfections or impurities sometimes exist, a visible light LED will sometimes emit weak visible light, by having ultraviolet light applied by an ultraviolet light LED excite the visible light LED

Methodology Applied

Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

a light guide plate

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentUS10290166B2Linear light source, optical sensor, differentiation unit, and automatic transaction apparatus using the same

Publication Date: 2019.05.14 OKI ELECTRIC INDUSTRY CO LTD

AI summary

[Object] To reduce the influence on a visible light LED exerted by ultraviolet light applied by an ultraviolet light LED.[Solution] A linear light source including an ultraviolet light emitting diode (1a), a visible light emitting diode (3a), and a light guide (5). The ultraviolet light emitting diode (1a) and the visible light emitting diode (3a) are disposed at least at one end in an optical axis direction of the light guide (5), and are disposed with an optical axis shifted and by providing a level difference in the optical axis direction. Here, the ultraviolet light emitting diode (1a) and the visible light emitting diode (3a) are mounted on an inverted L-shaped heat sink (6a), and an ultraviolet light blocking filter (2) is disposed in front of the visible light emitting diode (3a).