Light-Shielding Film Composition for Solid-State Image Sensors
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Solution Overview
Problem
Conventional light-shielding films in liquid crystal display devices and solid-state image sensing devices face issues with light-shielding effectiveness, pattern shape deterioration, and peeling due to high transmittance in the visible region, especially when using carbon black or titanium black pigments, and the complexity of vapor deposition methods.
Innovation Solution
A light-shielding film composition incorporating titanium atom-containing black titanium pigments and organic pigments like red, yellow, violet, or orange pigments, which are selectively formulated to achieve low transmittance in the visible region (400-700 nm) while maintaining high light-shielding capability, preventing peeling, and simplifying the film formation process by photopatterning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon black is used as the light-shielding pigment, then high light-shielding concentration across wide wavelength regions is achieved, but optical density in short-wavelength region becomes extremely high causing insufficient exposure and pattern deterioration
Solution Approach 1:
The patent changes the optical parameters of the light-shielding film by replacing carbon black with titanium-containing black pigment, which has different light absorption characteristics. This pigment provides appropriate optical density across the spectrum without excessive absorption in the ultraviolet region, enabling proper exposure while maintaining light-shielding effectiveness.
Solution Approach 2:
The patent uses a composite pigment system combining titanium-containing black pigment with organic pigments (red, yellow, violet, or orange) to achieve balanced light-shielding properties. This composite approach allows optimization of optical density across different wavelength regions, preventing both insufficient exposure and excessive light-shielding that would cause pattern deterioration.
2Manufacturing precision
If titanium-containing black pigment is used, then pattern exposure with ultraviolet light is improved, but light-shielding property in visible region is reduced allowing transmitted light to cause noise
Solution Approach 1:
The patent combines titanium-containing black pigment with specific organic pigments (red, yellow, violet, or orange) to create a composite light-shielding system. The organic pigments compensate for the reduced visible light-shielding capability of titanium pigment alone, achieving comprehensive light-shielding across both ultraviolet and visible regions while maintaining good exposure characteristics.
Solution Approach 2:
The patent optimizes the light-shielding properties at different wavelength regions by selecting specific organic pigments that target particular wavelength ranges. This allows the composition to have appropriate light-shielding characteristics in both the ultraviolet region (for exposure) and visible region (for noise prevention), achieving local optimization of optical properties.
3Reliability
If vapor deposition method is used to form light-shielding section, then light-shielding function is achieved, but film surface warps due to shrinkage causing poor adhesion and complex process steps
Solution Approach 1:
The patent replaces the vapor deposition process (physical vapor transport) with a solution-based coating method followed by drying and curing. This substitution eliminates the shrinkage and warping issues inherent in vapor deposition, simplifying the manufacturing process while maintaining light-shielding functionality through the use of properly formulated pigment compositions.
Solution Approach 2:
The patent changes the formulation parameters of the light-shielding composition by using titanium-containing black pigment and organic pigment combinations that provide adequate light-shielding properties without requiring the complex vapor deposition process. This allows simpler solution-based application methods while achieving the desired optical performance.
4Reliability
If vapor-deposited film is used, then light-shielding section is formed, but light reflecting property causes side effects
Solution Approach 1:
The patent uses a composite pigment system with titanium-containing black pigment and organic pigments that provides superior light absorption compared to vapor-deposited metal films. This composite approach eliminates the light-reflecting properties of vapor-deposited films, reducing optical side effects while maintaining effective light-shielding through comprehensive absorption across relevant wavelength ranges.
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 precise light-shielding pattern with improved adhesion and reduced noise, enhancing color reproducibility and optical density, while avoiding the limitations of traditional pigments and deposition methods.
Implementation Method 1
a light-shielding film which has a maximum value of transmittance of light having a wavelength of 400 to 700 nm of 1.5% or less when a light transmittance of light having a wavelength of 650 nm is 0.2%, has a wavelength exhibiting a maximum transmittance at 400 to 550 nm, and has a light transmittance at a wavelength of 400 nm of 0.1% or more
Data Source
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AI summary
The present invention provides a colored composition for a light-shielding film including at least one selected from titanium atom-containing black titanium pigments and at least one organic pigment selected from the group consisting of a red organic pigment, a yellow organic pigment, a violet organic pigment, and an orange color organic pigment, which has a maximum value of the transmittance of light having a wavelength of 400 to 700 nm of 1.5% or less when a film is formed such that the light transmittance at a wavelength of 650 nm is 0.2%, has a wavelength showing the maximum transmittance at 400 to 550 nm, and has a light transmittance at a wavelength of 400 nm of 0.1% or more.