Near Infrared Cutoff Filter Glass Cu Valence Control
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Solution Overview
Problem
Miniaturization of cameras with solid state imaging sensors requires a near infrared cutoff filter glass that maintains high visible light transmittance while reducing near infrared transmittance, which is challenging due to the need for increased Cu concentration in the glass, leading to deteriorated optical properties.
Innovation Solution
A near infrared cutoff filter glass composition with specific ratios of P, F, Al, R, R', and Cu, where the Cu+/total Cu ratio is controlled between 0.01% and 4.0%, ensuring high visible light transmittance and low near infrared transmittance, achieved by precise control of Cu valence and glass thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the glass is made thin to accommodate miniaturization, then the device size is reduced, but the Cu concentration must be increased which deteriorates visible light transmittance
Solution Approach 1:
The patent changes the chemical composition parameters of the glass by strictly controlling the Cu+ content to within 0.01 to 4.0% of total Cu, and optimizing the ratios of P, F, Al, R, and R' components. This parameter optimization allows the glass to maintain high visible light transmittance while achieving sufficient NIR cutoff performance in thin configurations.
2Object-affected harmful factors
If the Cu concentration is increased to achieve low near infrared transmittance, then the NIR cutoff performance is improved, but the visible light transmittance deteriorates
Solution Approach 1:
The patent optimizes the Cu concentration parameter to a specific range (0.01 to 4.0% of total Cu as Cu+) and adjusts the ratios of other glass components (P: 30-50%, F: 10-70%, Al: 5-20%, R: 20-40%, R': 5-30%). This balanced parameter set achieves effective NIR absorption while preserving visible light transmittance.
Solution Approach 2:
The patent creates a composite glass material incorporating multiple components (P, F, Al, R, R', and Cu) with optimized ratios. This composite formulation synergistically combines the NIR-absorbing properties of Cu with the optical transparency provided by the fluorophosphate glass matrix, achieving both NIR cutoff and visible light transmittance.
3Object-affected harmful factors
If the Cu concentration is increased to maintain optical properties in thin glass, then the NIR absorption is enhanced, but the overall optical quality deteriorates
Solution Approach 1:
The patent precisely controls the Cu+ concentration parameter within 0.01 to 4.0% of total Cu and optimizes the overall glass composition ratios. This controlled parameter adjustment ensures sufficient NIR absorption while maintaining excellent optical quality, weather resistance, and manufacturing stability.
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 solution provides a near infrared cutoff filter glass with superior optical properties, maintaining high visible light transmittance and low near infrared transmittance, suitable for miniaturized imaging devices, while avoiding the need for excessive Cu concentration that degrades visible light transmittance.
Implementation Method 1
an optical glass having Cu added to fluorophosphate glass, in order to selectively absorb wavelengths in the near infrared region
Data Source
AI summary
To provide a near infrared cutoff filter glass which is excellent in optical properties such that the transmittance of visible light is high, and the transmittance of near infrared light is low. A near infrared cutoff filter glass comprising components of P, F, Al, R (R is at least one member selected from Li, Na and K), R′ (R′ is at least one member selected from Mg, Ca, Sr, Ba and Zn) and Cu, wherein (Cu+/the total amount of Cu)×100[%] is within a range of from 0.01 to 4.0%.