Bistable Optical Element Attenuates Laser Light

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Solution Overview

Problem

Existing laser-based lighting devices face safety concerns due to the potential for high-intensity laser light to escape in case of component failure, particularly with the damage or disappearance of the remote phosphor, leading to unsafe exposure and increased hazard classification, which complicates market acceptance and reliability.

Innovation Solution

A laser-based lighting device incorporating a bistable optical element that changes from a transmissive to an attenuative state based on a threshold light output value, preventing unsafe levels of laser light from escaping without the need for additional electrical circuitry or sensors, utilizing materials like photochromic, thermochromic, or optical phase change materials to absorb or scatter excessive light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a laser-based lighting device uses a remote phosphor for wavelength conversion, then high brightness light can be produced, but unsafe high-intensity laser light may escape in case of phosphor damage or disappearance

Engineering Contradiction:

ImprovebrightnessVSAvoidlaser light exposure hazard

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

A safety optic element is introduced as an intermediary component between the laser light source and the output. This element selectively attenuates high-intensity laser light while allowing normal operation light to pass through, thereby mediating between the bright light requirement and the safety hazard prevention

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the potentially harmful high-intensity laser light into a useful safety signal. When the phosphor is damaged and high-intensity laser light escapes, it triggers the safety optic element to activate and attenuate the light, transforming the harmful condition into a beneficial safety response

Inventive Principle:

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

2Object-affected harmful factors

If additional electrical circuitry and sensors are added to detect and prevent unsafe laser light exposure, then safety can be improved, but device complexity and cost increase

Engineering Contradiction:

Improvelaser light exposure hazardVSAvoidelectrical components

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The safety optic element is designed to automatically respond to high-intensity laser light without requiring external detection or control systems. The element self-activates when exposed to unsafe light levels, eliminating the need for sensors, circuitry, and power sources that would otherwise be required

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces an electrical control system (sensors, circuitry, power management) with a passive optical system. The safety function is achieved through optical properties of the safety optic element rather than through electrical measurement and control mechanisms

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 enhances safety by ensuring that the lighting device attenuates high-intensity laser light to a safe level, reducing the risk of eye exposure and lowering hazard classification, while also enabling miniaturization and potentially lowering costs by eliminating the need for complex electrical components.

Implementation Method 1

The optical element comprises a bistable optical material that can change from an optical transmissive state to an optical attenuative state depending on a threshold value of the first light output

Methodology Applied

Scientific EffectPhotochromism: Photochromism

Implementation Method 2

utilizing materials like photochromic, thermochromic, or optical phase change materials to absorb or scatter excessive light

Methodology Applied

Scientific EffectThermochromism: Thermochromism

Implementation Method 3

The optical element comprises a bistable optical material that can change from an optical transmissive state to an optical attenuative state

Methodology Applied

Scientific EffectPhase change: Phase Change

Data Source

PatentUS12181147B2Laser-based lighting device

Publication Date: 2024.12.31 SIGNIFY HOLDING BV

AI summary

This invention relates to a safety measure taken against unsafe exposure of high-intensity laser light that is relevant for the reliable and safer operation of laser-based lighting devices. According to this invention, a lighting device comprises a first light-emitting semiconductor device and a light-conversion device. The first light-emitting semiconductor device is a laser device configured to generate a first light output and the 5light-conversion device is configured to receive the first light output and convert at least part of the first light output into a converted light output. The lighting device further comprises an optical element configured to receive the converted light output from the light-conversion device. The optical element is configured to transmit the converted light output and the first light output, and attenuate the first light output above a threshold value of the first light output.