Copper Phosphonate Optical Filter for Thin UV–IR Absorption
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Solution Overview
Problem
Existing optical filters for solid-state imaging sensors face challenges in achieving desired transmittance properties with thinner layers and simplified production processes, particularly in UV-IR absorption, and there is uncertainty about the transmittance properties of certain absorber materials.
Innovation Solution
An optical filter with a light-absorbing layer having a thickness of 120 μm or less, composed of copper phosphonate and an organic dye, achieving specific transmittance requirements and using a composition with controlled by-product concentration to enhance absorption performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a light-absorbing layer is made thinner to reduce imaging apparatus size, then the size and thickness are reduced, but achieving desired transmittance properties becomes more difficult
Solution Approach 1:
The patent changes the chemical composition parameters of the light-absorbing layer by using copper phosphonate compounds with specific molecular structures and controlled concentrations. This allows achieving the desired transmittance properties (70-90% in visible range, <5% in NIR range) with a reduced layer thickness of 120 μm or less, resolving the contradiction between thinness and optical performance.
2Object-affected harmful factors
If conventional UV-IR absorbers are used, then infrared and ultraviolet light can be absorbed, but the production process becomes complex and productivity decreases
Solution Approach 1:
The patent merges UV absorption, visible light transmission, and NIR absorption functions into a single light-absorbing layer using copper phosphonate compounds. This eliminates the need for separate UV-IR absorbing layers and infrared-absorbing glass substrates required by conventional methods, significantly simplifying the production process and improving productivity while maintaining effective broad-spectrum absorption.
3Manufacturing precision
If multiple layers are used to achieve desired transmittance properties, then optical performance is improved, but device complexity increases
Solution Approach 1:
The copper phosphonate-containing light-absorbing layer is designed to perform multiple functions simultaneously: UV absorption, visible light transmission, and NIR absorption. This multi-functional layer replaces multiple separate layers required by conventional approaches, reducing device complexity from multi-layer structures to a single effective layer while maintaining or improving transmittance properties.
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 filter achieves high visible light transmittance, effective near-infrared shielding, and simplified production, conforming to human visual sensitivity with improved light absorption performance.
Implementation Method 1
an optical filter including a light-absorbing layer including a light absorber... The transmittance properties of optical filters including a light-absorbing layer are unlikely to be dependent on the incident angle
Data Source
AI summary
An optical filter (1a) has a thickness of 120 μm or less and satisfies the following requirements (i), (ii), (iii), and (iv): (i) an average transmittance in a wavelength range of 450 nm to 600 nm is 74% or more; (ii) a maximum transmittance in a wavelength range of 750 nm to 1080 nm is 1% or less; (iii) an infrared cut-off wavelength being a wavelength which lies in a wavelength range of 550 nm to 700 nm and at which a spectral transmittance is 50% is in a range of 600 nm to 680 nm; and (iv) an ultraviolet cut-off wavelength being a wavelength which lies in a wavelength range of 350 nm to 500 nm and at which a spectral transmittance is 50% is in a range of 350 nm to 420 nm.