Copper Phosphonic Acid Light Absorber for Infrared Blocking
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Solution Overview
Problem
Existing optical filters struggle to achieve high transmittance in the visible light region, particularly in the red band, while effectively blocking near-infrared light without the need for a reflective layer.
Innovation Solution
A light absorber with a transmission spectrum that satisfies specific requirements, including high average transmittance in the visible range and effective blocking of near-infrared light, achieved without a reflective layer by using a composition including a phosphonic acid and a copper component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light-absorbing layer with copper ion and phosphonic acid is used to block infrared light, then infrared blocking performance is improved, but transmittance in the red band increases (worsening)
Solution Approach 1:
The patent changes the chemical composition parameters of the light-absorbing layer by specifying particular phosphonic acids (aromatic phosphonic acid with 6-12 carbon atoms, aliphatic phosphonic acid with 2-6 carbon atoms) and controlling their molar ratios relative to copper ions (0.8-2.0), thereby adjusting the absorption spectrum to block infrared light while maintaining red band transmittance
Solution Approach 2:
The patent creates a composite light-absorbing layer combining copper ions with specific phosphonic acid compounds, where the synergistic interaction between these components achieves selective infrared absorption while preserving visible light transmission properties
2Object-affected harmful factors
If the cut-off wavelength is adjusted to 600-680 nm to block infrared light, then infrared blocking is improved, but red band transmittance decreases (worsening)
Solution Approach 1:
The patent optimizes the cut-off wavelength parameter within the 600-680 nm range while compensating through specific phosphonic acid selection and concentration ratios, thereby achieving infrared blocking without excessive red band absorption
3Object-affected harmful factors
If a reflective layer is added to improve infrared blocking, then infrared blocking performance is improved, but device complexity increases
Solution Approach 1:
The patent extracts the infrared blocking function from a separate reflective layer and integrates it directly into the light-absorbing layer through copper-phosphonic acid complex formation, thereby eliminating the need for additional reflective layers and simplifying the overall optical filter structure
Solution Approach 2:
The patent merges the infrared blocking function with the existing light-absorbing layer by incorporating copper ions and phosphonic acids, combining multiple functions (visible light transmission, infrared blocking) into a single layer rather than requiring separate reflective and absorbing layers
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 light absorber achieves high transmittance in the visible light region, particularly in the red band, while satisfactorily blocking near-infrared light, thus improving image quality and reducing ghosting and flare in imaging apparatuses.
Implementation Method 1
Light absorbents formed from a phosphonic acid and a copper ion are known for such use... an optical filter including a film including a light absorbent
Data Source
AI summary
A transmission spectrum of a light absorber 10 at an incident angle of 0° satisfies the following requirements: (I) an average transmittance in a wavelength range of 450 nm to 600 nm is 75% or more; (II) a first wavelength that lies in a wavelength range of 350 nm to 450 nm and at which a transmittance is 50% is 380 nm or more and 440 nm or less; (III) a second wavelength that lies in a wavelength range of 650 nm to 750 nm and at which a transmittance is 50% is 680 nm or more and 740 nm or less; (IV) a maximum transmittance in a wavelength range of 350 nm to 370 nm is 1% or less; (V) a maximum transmittance in a wavelength range of 800 nm to 900 nm is 5% or less; and (VI) a maximum transmittance in a wavelength range of 1100 nm to 1200 nm is 5% or less.