UV-IR Absorbing Layer Optical Filter Spectral Control
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Solution Overview
Problem
Existing optical filters, such as those described in Patent Literature 1, do not have desirable light absorption properties in the wavelength ranges of 350 nm to 400 nm and 650 nm to 800 nm, making it difficult to achieve the desired optical characteristics with a simple structure.
Innovation Solution
An optical filter with a UV-IR-absorbing layer that absorbs infrared and ultraviolet light, exhibiting an average transmittance of 78% or more in the 450 nm to 600 nm range, spectral transmittance of 1% or less in the 750 nm to 1080 nm range, and specific cut-off wavelengths to match human visual sensitivity, achieved without additional layers beyond the UV-IR-absorbing layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a near-infrared-absorbing filter is used to absorb light with wavelengths of 800 nm to 1200 nm, then the filter effectively blocks near-infrared light, but the filter has poor light absorption properties in the wavelength ranges of 350 nm to 400 nm and 650 nm to 800 nm
Solution Approach 1:
The patent combines a near-infrared absorber and a UV absorber into a single UV-IR absorbing layer. The near-infrared absorber (e.g., copper phthalocyanine) absorbs light in the 650-1100 nm range, while the UV absorber (e.g., benzotriazole derivative) absorbs light in the 300-400 nm range. This merging of multiple absorption functions into one layer resolves the contradiction by achieving broad spectral coverage while maintaining simple structure.
Solution Approach 2:
The patent uses composite materials by combining different absorber substances with complementary absorption characteristics. The UV-IR absorbing layer contains both near-infrared absorbing compounds (like copper phthalocyanine) and UV absorbing compounds (like benzotriazole derivatives), creating a composite material that simultaneously addresses multiple wavelength ranges with enhanced reliability across the spectrum.
2Reliability
If additional layers or dielectric multilayer films are added to improve light absorption in specific wavelength ranges, then the optical characteristics can be enhanced, but the device complexity increases
Solution Approach 1:
The UV-IR absorbing layer serves multiple functions simultaneously: it absorbs ultraviolet light (300-400 nm), transmits visible light (450-600 nm with 78% or more transmittance), and absorbs near-infrared light (650-1100 nm). This multi-functionality in a single layer eliminates the need for separate UV filter layers and IR cut layers, reducing device complexity while maintaining excellent optical characteristics.
Solution Approach 2:
The patent merges the functions of UV blocking and IR cutting into one UV-IR absorbing layer. By combining the UV absorber and near-infrared absorber in the same layer, the patent achieves the optical performance of multiple layers with a single layer, thereby simplifying the overall filter structure and reducing the number of components.
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 effectively transmits light in the 450 nm to 600 nm range while cutting off light in the 300 nm to 400 nm and 650 nm to 1100 nm ranges, conforming better to human visual sensitivity and reducing the need for additional layers or dielectric multilayer films, thus improving image quality and reducing color tone issues.
Implementation Method 1
a UV-IR-absorbing layer capable of absorbing infrared light and ultraviolet light
Data Source
AI summary
An optical filter (1a) includes a UV-IR-absorbing layer and has the following characteristics (i) to (v) when light with wavelengths of 300 nm to 1200 nm is incident at an incident angle of 0°: (i) an average transmittance of 78% or more in the wavelength range of 450 nm to 600 nm; (ii) a spectral transmittance of 1% or less in the wavelength range of 750 nm to 1080 nm; (iii) a spectral transmittance of 1% or less in the wavelength range of 300 nm to 350 nm; (iv) a decreasing spectral transmittance with increasing wavelength in the wavelength range of 600 nm to 750 nm and a first IR cut-off wavelength in the wavelength range of 620 nm to 680 nm; and (v) an increasing spectral transmittance with increasing wavelength in the wavelength range of 350 nm to 450 nm and a first UV cut-off wavelength in the wavelength range of 380 nm to 430 nm.