Optical Filter Heat Resistance via Light-Absorbing Resin
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Solution Overview
Problem
Existing optical filters used in imaging apparatuses, such as those employing charge coupled devices (CCDs) or complementary metal oxide semiconductors (CMOS), face challenges in maintaining performance and yield due to heat resistance issues during screening tests, particularly when exposed to high temperatures.
Innovation Solution
The development of an optical filter comprising a light-absorbing compound and a resin, which maintains specific transmission spectra before and after a heating test at 125°C for 200 hours, ensuring minimal change in transmittance and absorption characteristics across various wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an optical filter uses a light-reflecting dielectric multilayer film to block infrared or ultraviolet light, then the spectral sensitivity of the solid-state image sensing device can approximate human visual sensitivity, but the transmittance properties become dependent on the incident angle causing color change and color unevenness, and ghosting and flare occur in backlit or nightscape conditions
Solution Approach 1:
The patent changes the fundamental parameter of light interaction from reflection to absorption. The optical filter uses a light-absorbing layer with specific absorption coefficients to block infrared and ultraviolet light, eliminating the incident angle dependency and optical defects associated with reflective films while maintaining spectral sensitivity matching.
Solution Approach 2:
The patent employs a composite structure consisting of a light-absorbing layer (containing UV absorber and infrared absorber) combined with a resin matrix. This composite material approach enables simultaneous achievement of UV and IR blocking with angle-independent transmittance properties, resolving the technical contradiction between spectral matching and image quality consistency.
2Object-generated harmful factors
If an optical filter includes a light-absorbing layer, then ghosting and flare are reduced in backlit or nightscape conditions and the size and thickness are reduced, but the yield of products decreases due to heat resistance issues during screening tests at high temperatures
Solution Approach 1:
The patent modifies the thermal and optical parameters of the light-absorbing layer by selecting materials with appropriate absorption coefficients and thermal stability. The resin and absorber combination is designed to withstand screening test temperatures while maintaining optical performance, thereby resolving the contradiction between harmful factor reduction and productivity.
Solution Approach 2:
The patent uses organic UV absorbers and infrared absorbers that can be readily synthesized and incorporated into the resin matrix. These materials provide the necessary optical filtering without requiring complex or expensive heat-resistant ceramics, thus maintaining high product yield while reducing ghosting and flare.
3Manufacturing precision
If the optical filter uses existing light-absorbing compositions, then the optical properties can be achieved, but the yield of products including the optical filter decreases due to insufficient heat resistance during screening tests
Solution Approach 1:
The patent creates a composite material system combining a resin base with specifically selected UV absorber and infrared absorber components. This composite approach enables simultaneous optimization of optical properties (transmittance control) and thermal reliability (heat resistance), resolving the contradiction between manufacturing precision and reliability.
Solution Approach 2:
The resin acts as an intermediary matrix that binds the UV absorber and infrared absorber particles, providing both optical functionality and thermal stability. This intermediary material enables the light-absorbing layer to maintain structural integrity and optical performance during high-temperature screening tests, thereby improving both manufacturing precision and heat resistance reliability.
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
This optical filter design enhances heat resistance and maintains optimal performance even after rigorous heating tests, thereby increasing the yield of products incorporating the filter and reducing manufacturing costs.
Implementation Method 1
an optical filter including a layer including a light absorbent
Implementation Method 2
a heating test in which the optical filter is heated at 125° C. for 200 hours
Data Source
AI summary
Provided is an optical filter (1a) including a light-absorbing compound and a resin including the light-absorbing compound. The optical filter (1a) has a first transmission spectrum satisfying the following requirements (i), (ii), (iii), and (iv). An absolute value |λ1-UV25° C.−λ2-UV25° C.| is 8 nm or less. (i) An average transmittance in a wavelength range of 300 nm to 380 nm is 1% or less. (ii) An average transmittance in a wavelength range of 450 nm to 600 nm is 80% or more. (iii) An average transmittance in a wavelength range of 700 nm to 725 nm is 10% or less. (iv) An average transmittance in a wavelength range of 950 nm to 1150 nm is 5% or less.