Optical Filter with Copper Phosphate Ester Near-Infrared Absorption Layer
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Solution Overview
Problem
Conventional optical filters with plastic substrates suffer from flare phenomena, such as wifi-type and petal-type flare, when used in electronic devices with image sensors, due to their inability to effectively absorb near-infrared rays, leading to optical distortion.
Innovation Solution
An optical filter comprising a polymer film with a near-infrared absorption layer made of a copper phosphate ester compound and organic dyes, which selectively absorbs near-infrared light while maintaining high transmittance in the visible region, reducing optical distortion and allowing for a thin film design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a plastic substrate is used to replace glass substrate for thinning the optical filter, then the optical filter thickness is reduced, but flare phenomenon occurs causing optical distortion
Solution Approach 1:
The patent uses a composite structure consisting of a plastic substrate combined with a near-infrared absorption layer containing copper phosphate ester and organic dyes. This composite material approach allows the optical filter to maintain the thinness advantage of plastic substrates while adding the infrared absorption capability needed to prevent flare phenomena, thus resolving the contradiction between thickness reduction and optical distortion prevention.
Solution Approach 2:
The patent applies local quality by adding a specialized near-infrared absorption layer only where needed on the plastic substrate. This layer contains specific materials (copper phosphate ester and organic dyes with maximum absorption wavelengths of 650-1200 nm) that selectively absorb near-infrared light without affecting visible light transmission, thereby preventing flare at critical locations while maintaining overall filter thinness.
2Adaptability or versatility
If a plastic substrate is used instead of glass substrate, then down-sizing and higher integration are achieved, but near-infrared absorption capability is insufficient
Solution Approach 1:
The patent combines plastic substrate material with near-infrared absorption materials (copper phosphate ester compound and organic dyes) to create a composite optical filter. This composite structure provides both the size reduction benefits of plastic and the reliable near-infrared absorption capability, achieving down-sizing without sacrificing optical performance.
Solution Approach 2:
The patent changes the optical parameters of the plastic substrate by incorporating near-infrared absorption materials that have maximum absorption wavelengths in the 650-1200 nm range. This parameter modification enables the plastic substrate to achieve sufficient near-infrared absorption capability while maintaining its inherent advantages of small size and high integration potential.
3Reliability
If conventional near-infrared absorption materials are used, then infrared absorption is achieved, but visible light transmittance is reduced
Solution Approach 1:
The patent uses local quality by selecting materials with specific optical properties: copper phosphate ester and organic dyes that have maximum absorption wavelengths in the 650-1200 nm near-infrared range. These materials selectively absorb only near-infrared light while allowing visible light to pass through, thus achieving reliable infrared absorption without reducing visible light transmittance.
Solution Approach 2:
The patent changes the absorption wavelength parameters of the filter materials to target specifically the near-infrared region (650-1200 nm) while maintaining transparency in the visible region. This parameter optimization ensures that the optical filter reliably absorbs near-infrared radiation for preventing flare while preserving excellent visible light transmission for image quality.
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 significantly reduces optical distortion in image sensors, enabling a thinner design suitable for downsized camera modules and electronic devices while maintaining excellent visible light transmittance and near-infrared absorption.
Implementation Method 1
The near infrared absorption layer is configured to transmit light in a visible region and to selectively absorb at least one part of light in a near infrared region
Data Source
AI summary
Disclosed are an optical filter including a near infrared absorption layer on a polymer film. The polymer film has a* of about −5.0 to about +5.0 and b* of about −5.0 to about +5.0 in a color coordinate expressed by a CIE Lab color space. The near infrared absorption layer may be configured to transmit light in a visible region and to selectively absorb at least one part of light in a near infrared region. The near infrared absorption layer includes a first near infrared absorption material including a copper phosphate ester compound and a second near infrared absorption material including at least two different organic dyes. The second near infrared absorption material has a maximum absorption wavelength (λmax) in a wavelength region of about 650 nm to about 1200 nm. An electronic device may include the optical filter.