Blue Laser Beam Guidance Element Solarization Resistance

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Solution Overview

Problem

Modern laser-based projectors face challenges with thermal load and solarization effects due to high luminous fluxes and power densities, leading to reduced transmission and increased thermal lens effects in optical components, which affect projection quality and long-term stability.

Innovation Solution

The development of an imaging system with a beam guidance element made of specific glasses that have a quality factor and induced absorbance properties, allowing for high solarization resistance at high power densities, specifically designed for laser light sources in the blue, green, and red spectral ranges, to mitigate thermal lens effects and maintain image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If laser-based projectors use high luminous fluxes and power densities to improve projection brightness and performance, then projection quality improves, but thermal load on optical components increases causing solarization effects and reduced transmission

Engineering Contradiction:

Improveprojection brightnessVSAvoidoptical component stability

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the glass material by incorporating specific metal oxides (Nb2O5, Ta2O5, TiO2, ZrO2) in controlled amounts to modify the glass network structure. This alters the optical properties including solarization resistance and transmission characteristics, enabling the glass to withstand high power densities without degradation while maintaining projection quality

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite glass material combining multiple oxide components (silica base with added metal oxides) to achieve synergistic effects. The composite structure provides both high transmission in the visible range and exceptional solarization resistance, resolving the contradiction between brightness and reliability

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If traditional optical glasses are used in prism arrangements to guide light channels, then the optical system functions, but absorption losses increase causing temperature gradients and thermal lens effects

Engineering Contradiction:

Improveoptical system functionalityVSAvoidlight absorption losses

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The patent optimizes the glass composition parameters to achieve minimal absorption across the visible spectrum (380-750 nm). By adjusting the ratios of network formers and modifiers, and incorporating high-refractive-index oxides, the glass achieves both functional optical properties and low absorption losses, preventing thermal lens effects while maintaining prism functionality

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If the optical path length is increased to guide light through complex prism arrangements, then color channel mixing and guidance is achieved, but the probability of solarization effects increases

Engineering Contradiction:

Improvecolor channel guidance capabilityVSAvoidsolarization effects

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs a composite glass formulation with multiple protective oxide components that work synergistically to prevent solarization throughout the entire optical path. The extended path length is accommodated by the enhanced solarization resistance of the composite material, allowing complex prism arrangements to function without degradation from prolonged blue light exposure

Inventive Principle:

Principle #40Composite materials

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 imaging system effectively reduces unwanted imaging errors and thermal lens effects, ensuring high-quality image projection and extended component lifespan by utilizing glasses with optimized quality factors and absorbance properties.

Implementation Method 1

Light-guiding rods of this kind exploit the total internal reflection at the glass-air boundary

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

Any light absorption within the prism arrangement results in temperature gradients and thermal lens effects

Methodology Applied

Scientific EffectAbsorption: Absorption (EM radiation)

Implementation Method 3

at least one laser light source B having a wavelength λB in the spectral range from 380 nm to 490 nm

Methodology Applied

Scientific EffectLaser: Laser

Data Source

PatentUS20230090497A1Imaging system including beam guiding element having high solarization resistance in the blue spectral range

Publication Date: 2023.03.23 SCHOTT AG

AI summary

An imaging system, includes: a laser light source having a wavelength from 380 nm to 490 nm; and a beam guidance element, the laser light source configured for generating an average surface power density of more than 10 W/cm2, the beam guidance element including a glass which has a quality factor F(436 nm)=S(436 nm)*(Abs0(436 nm)+Abs1(436 nm))/k, wherein S(436 nm) is a thermality at a wavelength of 436 nm, Abs1(436 nm) is an additional absorbance in comparison to Abs0(436 nm) at a wavelength of 436 nm after an irradiation with a power density of 345 W/cm2 for 72 hours with a laser light having a wavelength of 455 nm, Abs0(436 nm) is an absorbance at a wavelength of 436 nm of a sample having a thickness of 100 mm without the irradiation, k is the thermal conductivity, and the quality factor F(436 nm) is <15 ppm/W.