Lead-Free Optical Glass for X-Ray Resistant Light Transmission
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Solution Overview
Problem
Optical glasses used in light guides and industrial endoscopes experience decreased light transmittance when irradiated with X-rays, especially when lead is present, leading to environmental pollution concerns and difficulty in recovering transmittance without lead.
Innovation Solution
An optical glass composition with specific ranges of components such as SiO2, La2O3, ZrO2, TiO2, and Na2O, which enhances refractive index and light intensity recovery after X-ray irradiation, while avoiding lead and minimizing environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lead is added to optical glass to maintain high refractive index, then light transmittance decreases after X-ray irradiation and environmental pollution occurs, but if lead is removed to improve environmental sustainability, then refractive index decreases and light transmission becomes difficult
Solution Approach 1:
The patent changes the chemical composition parameters of the optical glass by replacing lead oxide with a specific combination of bismuth oxide (0.1-10 wt%), zinc oxide (5-20 wt%), and boron oxide (10-30 wt%). This parameter substitution maintains the refractive index while eliminating the harmful lead component and improving resistance to X-ray induced transmittance degradation.
Solution Approach 2:
The patent creates a composite glass system combining multiple oxide components (silica, bismuth oxide, zinc oxide, boron oxide, and other metal oxides) in specific proportions. This composite formulation achieves the desired optical properties and X-ray resistance without relying on lead, thus resolving the contradiction between environmental sustainability and optical performance.
2Object-generated harmful factors
If lead-free glass composition is used to eliminate environmental pollution, then refractive index is reduced making light transmission difficult, but if lead is used to maintain high refractive index, then environmental pollution occurs
Solution Approach 1:
The patent adjusts the composition parameters by incorporating bismuth oxide (0.1-10 wt%) and zinc oxide (5-20 wt%) as alternative high-refractive-index contributors. These components compensate for the removal of lead oxide while maintaining the necessary refractive index for effective light transmission in optical fibers.
Solution Approach 2:
The patent introduces zinc oxide and boron oxide as intermediary substances that mediate between the conflicting requirements of lead-free composition and high refractive index. These intermediaries contribute to both the optical properties and the overall glass matrix stability, enabling lead-free glass to achieve the required refractive index.
3Reliability
If optical glass is irradiated with X-rays for application in light guides, then light transmittance decreases making transmission difficult, but if source light is irradiated to recover transmittance, then recovery is incomplete without lead
Solution Approach 1:
The patent modifies the glass composition parameters by adding specific metal oxides (bismuth oxide, zinc oxide, boron oxide) that enhance the glass matrix's resistance to X-ray induced damage. This compositional adjustment reduces the formation of color centers and minimizes transmittance loss after X-ray irradiation, maintaining reliable light transmission.
Solution Approach 2:
The patent incorporates protective oxide components (particularly boron oxide and zinc oxide) in advance into the glass composition to cushion against the harmful effects of X-ray irradiation. These components preemptively protect the glass structure from X-ray induced degradation, reducing transmittance loss before it occurs.
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 optical glass achieves a high light intensity recovery rate and maintains high refractive index, ensuring effective light transmission even after X-ray exposure, with improved environmental sustainability by excluding lead.
Implementation Method 1
a recovery rate of transmitted light intensity increases when source light is irradiated after X-ray irradiation
Implementation Method 2
a refractive index (n d ) is raised by means of the glass composition
Data Source
AI summary
Provided is optical glass that does not contain lead, which is an environmental pollutant. The optical glass is ideal for the transmission of light even after being exposed to X-rays, and has a high refractive index. The optical glass comprises, by mass% in terms of oxide versus the glass total mass, 1.0% to 60.0% of an SiO2 component, and one or more selected from the group consisting of an La2O3 component, ZrO2 component, TiO2 component, Nb2O5 component, and Ta2O5 as essential components. The optical glass has a refractive index (nd) of 1.50 or greater, and has a light intensity recovery rate of 45% or greater when the glass having been irradiated with X-rays with a dose of 2.5 Gy is irradiated with light of a xenon lamp for 11 hours.