Near-Infrared Cut Filter Composition for Heat-Resistant Imaging Pixels
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Solution Overview
Problem
Existing solid-state imaging devices face challenges with near-infrared cut filters that suffer from void generation and reduced heat resistance when exposed to high-temperature environments, affecting their spectral characteristics and color resolution.
Innovation Solution
A structure comprising first pixels with a laminate of a color filter and a near-infrared cut filter, where the near-infrared cut filter includes a near-infrared absorbing colorant, a resin with a glass transition temperature of 100°C or higher, and a surfactant, specifically using squarylium or croconium compounds, and a cyclic olefin resin, which enhances heat resistance and suppresses void formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a near-infrared cut filter is used in a solid-state imaging device, then luminosity correction is achieved, but voids are generated on the filter surface when exposed to high-temperature and high-humidity environments
Solution Approach 1:
The patent uses a composite material consisting of a near-infrared absorptive dye dispersed in a transparent resin matrix to form the near-infrared cut filter. This composite structure allows the filter to block near-infrared light while maintaining visible light transmission and improving resistance to void formation in high-temperature environments
Solution Approach 2:
The patent changes the physical and chemical parameters of the filter by selecting specific resins with appropriate glass transition temperatures and viscosities, and by controlling the concentration of the near-infrared absorptive dye. These parameter adjustments optimize the filter's performance in preventing void formation while maintaining its spectral characteristics
2Reliability
If a near-infrared absorptive material is used in the near-infrared cut filter, then near-infrared blocking is achieved, but visible transparency is reduced due to discoloration from high-temperature heating
Solution Approach 1:
The patent carefully selects and adjusts parameters including the type of near-infrared absorptive dye, its concentration in the resin, and the resin's glass transition temperature. These parameter optimizations ensure the filter blocks near-infrared light effectively while minimizing visible light absorption and preventing discoloration during high-temperature processing
Solution Approach 2:
The patent achieves different optical properties in different regions of the spectrum by designing the composite material to have selective absorption characteristics. The near-infrared absorptive dye is formulated to absorb specifically in the near-infrared range while the resin matrix maintains high transparency in the visible range, creating a filter with spatially selective optical properties
3Ease of manufacture
If the near-infrared cut filter is subjected to high-temperature heating treatment during production, then pixel formation is completed, but the filter's heat resistance is insufficient causing discoloration
Solution Approach 1:
The patent addresses the heat resistance issue by selecting resins with glass transition temperatures of 80°C or higher, and preferably 100°C or higher. This parameter selection ensures the filter material remains stable during high-temperature heating treatment processes such as solder reflow, preventing discoloration and degradation of the near-infrared absorptive dye
Solution Approach 2:
The patent provides beforehand cushioning against thermal damage by pre-selecting heat-resistant resin materials and optimizing the dye-resin composition before the high-temperature processing step. This preparatory material selection creates a buffer that protects the near-infrared absorptive properties during subsequent high-temperature manufacturing operations
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 cut filter with improved heat resistance and spectral characteristics, reducing void generation and maintaining color resolution even in high-temperature conditions.
Implementation Method 1
the near-infrared cut filter includes a near-infrared absorbing colorant
Implementation Method 2
a resin having a glass transition temperature of 100° C. or higher
Data Source
AI summary
A structure has first pixels constituted of a laminate including a light-receiving element, a color filter, and a near-infrared cut filter, and second pixels including a near-infrared transmitting filter. The near-infrared cut filter includes a predetermined near-infrared absorbing colorant, a resin having a glass transition temperature of 100° C. or higher, and a surfactant.