Optical Filter Light-Absorbing Layer Incident Angle Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical filters fail to effectively block unnecessary light and prevent uneven coloring of images when the incident angle of light is larger than 35°, leading to variations in transmittance characteristics and potential image distortion.
Innovation Solution
An optical filter with a light-absorbing layer that includes a light absorber for the near-infrared region, designed to maintain consistent spectral transmittance characteristics across various incident angles, ensuring that the filter blocks unnecessary light without shifting the boundary between transmitted and blocked wavelengths, even at larger angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional optical filter with dielectric multilayer film is used, then the filter can block near-infrared light at normal incident angles, but the transmittance characteristics shift and uneven coloring occurs when light incident angle exceeds 35°
Solution Approach 1:
The patent changes the material parameter from conventional dielectric multilayer films to a light-absorbing layer containing specific infrared-absorbing dyes (cyanine-based, phthalocyanine-based, squarylium-based, or diimmonium-based dyes). This material parameter change makes the filter's transmittance characteristics insensitive to incident angle variations, maintaining stability across 0° to 65° while blocking near-infrared light effectively.
Solution Approach 2:
The patent uses composite material structure combining transparent resin with specific infrared-absorbing dyes to create a light-absorbing layer. This composite material achieves both high visible light transmittance and effective near-infrared blocking without the incident angle dependence problem of conventional dielectric multilayer films.
2Ease of manufacture
If the filter structure is simplified to reduce complexity, then manufacturing becomes easier, but the ability to maintain consistent transmittance across wide incident angles is compromised
Solution Approach 1:
The patent extracts and eliminates the complex dielectric multilayer film structure from conventional optical filters, retaining only the essential light-absorbing functional layer. This simplification removes the source of incident angle dependence while maintaining effective near-infrared blocking through the use of specific infrared-absorbing dyes in a transparent resin matrix.
3Object-affected harmful factors
If conventional near-infrared cut filters are used, then near-infrared light can be blocked at normal angles, but unnecessary light blocking is insufficient and image coloring occurs at large incident angles
Solution Approach 1:
The patent changes the optical parameter of the filter by using light-absorbing dyes with specific absorption characteristics that target near-infrared wavelengths while maintaining high visible light transmittance. This parameter optimization ensures effective near-infrared blocking without causing uneven image coloring even when light incident angles exceed 35°.
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 blocks unnecessary light and prevents uneven coloring of images, maintaining consistent image quality across different incident angles by ensuring minimal variation in transmittance characteristics, thus preventing image distortion.
Implementation Method 1
a light-absorbing layer that includes a light absorber for absorbing light in at least a portion of the near-infrared region
Data Source
AI summary
An optical (1a) includes a light-absorbing layer (10). The light-absorbing layer absorbs light in at least a portion of the near-infrared region. When light with a wavelength of 300 to 1200 nm is incident on the optical filter (1a) at an incident angle of 0°, the optical filter (1a) satisfies given spectral transmittance requirements. When an average of absolute values of differences each between a value of a normalized spectral transmittance for an incident angle x° and a value of a normalized spectral transmittance for an incident angle y° in the wavelength range of W nm to V nm (W<V) is expressed as ΔTSx/yW-V, the optical filter (1a) satisfies requirements ΔTS0/40380-530≤3%, ΔTS0/40450-650≤3%, and ΔTS0/40530-750≤3%.