Laser Processing Head Protector Fouling Detection by Temperature Sensing

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Solution Overview

Problem

Conventional dirt detecting means in laser processing heads, positioned at the same height as the protective glass, suffer from low intensity diffusely reflected light detection and are prone to interference from scattered light, making accurate detection of contaminants challenging.

Innovation Solution

A laser processing head with a detachable transparent protector and a temperature sensor that detects the temperature of the protector, using near-infrared processing laser light to heat contaminants and distinguish between reflected and black-body radiation light, allowing for accurate detection of contaminant adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the dirt detecting means is disposed at the rim of the protective glass, then the device complexity is reduced, but the measurement precision deteriorates due to low intensity of diffusely reflected light and interference from scattered light

Engineering Contradiction:

Improvedirt detecting means arrangementVSAvoidcontaminant detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary substance (contaminant particles) that converts the detection mechanism from direct light reflection measurement to temperature measurement. The contaminants absorb laser energy and convert it to thermal energy, which can be detected by temperature sensors. This intermediary conversion process resolves the contradiction by providing a detection method that is both simple in arrangement and precise in measurement.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the optical detection system (mechanical/optical arrangement of light sources and sensors at the rim) with a thermal detection system (temperature sensors). This substitution eliminates the problems of low light intensity and scattered light interference by using a completely different physical principle (thermal detection instead of optical reflection detection), thereby maintaining simplicity while improving precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If conventional optical detection methods are used, then the device structure is simple, but the reliability deteriorates due to false positives from scattered light and low signal intensity

Engineering Contradiction:

Improvedetection system structureVSAvoiddetection accuracy

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent changes the detection parameter from optical properties (light reflection intensity) to thermal properties (temperature). By measuring the temperature increase of contaminants rather than their optical reflection characteristics, the system eliminates false positives caused by scattered light and low signal intensity, thereby improving reliability without complicating the device structure.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful effect of laser energy absorption by contaminants (which causes heating) into a beneficial detection signal. The very process that degrades the protective glass (contaminant accumulation absorbing laser energy) becomes the detection mechanism itself, as the resulting temperature increase is easily measurable and unambiguous, improving reliability while keeping the system simple.

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 method enables reliable detection of contaminant adhesion on the transparent protector, reducing the risk of false positives and interference, and provides a clear indication for timely replacement, enhancing the accuracy and reliability of the detection process.

Implementation Method 1

using near-infrared processing laser light to heat contaminants

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 2

distinguish between reflected and black-body radiation light

Methodology Applied

Scientific EffectBlack-body radiation: Thermal Radiation

Data Source

PatentUS11904406B2Laser processing head and laser processing system using same

Publication Date: 2024.02.20 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

Laser processing head (20) of the present disclosure includes housing (30), transparent protector (40), and temperature sensor (70). Housing (30) includes an optical path of processing laser light (LB). Transparent protector (40) is detachably fixed to housing (30), passes processing laser light (LB), and suppresses dust of work material (W) entering into housing (30). Here, the dust is generated from the work material (W) irradiated with processing laser light (LB). Temperature sensor (70) detects the temperature of transparent protector (40).