Fingerprint Detection Filter Layer With Integrated IR Cutoff
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Solution Overview
Problem
Conventional detection devices using external IR cut filters are not suitable for thinness and cost-effectiveness, and color filters in LCD panels fail to achieve sensor characteristics equivalent to external IR cut filters, making it difficult to detect fingerprints under natural light.
Innovation Solution
A detection device with a filter layer made of green-colored resin material, having a peak transmittance of 90% or more at 550 nm, 80% or more at 600 nm, and 10% or less at 680-700 nm, which allows for effective fingerprint detection under natural light by using the same deposition process as color filters in LCD panels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an external IR cut filter is used to improve authentication accuracy, then the device thickness increases and manufacturing complexity increases
Solution Approach 1:
The patent merges the IR cut filter function with the color filter layer by integrating the IR cut resin material into the existing color filter structure. This allows the filter layer to simultaneously perform both color filtering and IR cutoff functions, eliminating the need for a separate external IR cut filter and thereby reducing device thickness while maintaining authentication accuracy
Solution Approach 2:
The filter layer is designed to serve multiple functions: it acts as both a color filter for display purposes and an IR cut filter for authentication. By using a resin material with specific spectral characteristics that blocks IR light while allowing visible light transmission, the single filter layer achieves both functions, improving authentication accuracy without adding device thickness
2Measurement precision
If an external IR cut filter is used to improve authentication accuracy, then manufacturing cost and process complexity increase
Solution Approach 1:
The patent combines the IR cut filter function with the color filter layer, allowing both functions to be achieved in a single manufacturing process. The filter layer is formed using conventional LCD color filter deposition techniques, eliminating the need for separate IR cut filter manufacturing steps and reducing overall manufacturing cost and complexity while maintaining authentication accuracy
Solution Approach 2:
The patent uses a resin material that replicates the spectral characteristics of traditional inorganic IR cut filters but can be manufactured using organic resin deposition processes. This allows the benefits of IR cut filtering to be copied through a more cost-effective and simpler manufacturing process that leverages existing color filter production capabilities
3Measurement precision
If inorganic film deposition process is used to achieve IR cut characteristics, then manufacturing cost increases
Solution Approach 1:
The patent changes the material parameter from inorganic film to organic resin while maintaining the desired spectral characteristics. The resin material is formulated to have peak transmittance of 90% or more at 550 nm, 80% or more at 600 nm, and 10% or less at 680-700 nm, replicating the optical performance of inorganic IR cut filters but enabling use of cheaper organic resin deposition processes
Solution Approach 2:
The patent copies the functional characteristics of inorganic IR cut filters using organic resin materials. By carefully selecting and formulating the resin composition, the patent achieves equivalent IR cutoff performance and visible light transmission properties without requiring expensive inorganic film deposition processes, thereby reducing manufacturing cost while maintaining sensor characteristics
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 enables accurate fingerprint detection under natural light conditions and improves the mass-productivity of the detection device by using a green-colored resin filter layer, satisfying the required spectral characteristics for fingerprint detection.
Implementation Method 1
the filter layer has a peak transmittance of 90% or more, a transmittance of 80% or more at a wavelength of 550 nm, a transmittance of 10% or more at a wavelength of 600 nm, and a transmittance of 10% or less at a wavelength of 680 nm to 700 nm
Data Source
AI summary
A detection device includes a photodetector, a filter layer overlapped on the photodetector and including a first color material having a peak transmittance for light in a first wavelength band, and a display panel arranged over the filter layer, wherein the filter layer has a peak transmittance of 90% or more, a transmittance of 80% or more at a wavelength of 550 nm, a transmittance of 10% is more at a wavelength of 600 nm, and a transmittance of 10% or less at a wavelength of 680 nm to 700 nm.