Plasmon Pixel Filter Layout for Narrow-Band Imaging Accuracy
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Solution Overview
Problem
Plasmon filters with a hole array structure face reduced detection accuracy for narrow band light due to shifting wavelength bands and widened peak widths as hole pitch changes, leading to decreased sensitivity and increased color mixture.
Innovation Solution
The imaging device incorporates a filter layer with varying thickness and hole or dot arrays to selectively filter light by pixel, adjusting the film thickness and pitch to optimize transmission or absorption bands for improved narrow band light detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the hole pitch is narrowed to achieve short wavelength transmission, then the transmission band shifts to short wavelength, but the sensitivity of the plasmon filter decreases
Solution Approach 1:
The patent applies local quality by varying the film thickness of the metal layer across different regions of the filter. Specifically, the filter includes a first region with a first thickness and a second region with a second thickness greater than the first thickness. This allows each region to be optimized for its specific wavelength range, maintaining sensitivity while achieving the desired short wavelength transmission in the first region.
Solution Approach 2:
The patent utilizes parameter changes by adjusting the film thickness parameter across different regions of the plasmon filter. The first region has a thinner film thickness optimized for short wavelength transmission, while the second region has a greater thickness optimized for maintaining sensitivity. This parameter variation resolves the contradiction between achieving short wavelength transmission and maintaining filter sensitivity.
2Measurement precision
If the hole pitch is widened to achieve long wavelength transmission, then the transmission band shifts to long wavelength, but the peak width and half width widen causing decreased detection accuracy
Solution Approach 1:
The patent applies local quality by creating distinct regions with different film thicknesses optimized for different wavelength ranges. The second region with greater thickness is specifically designed to maintain narrow peak widths and high spectral precision for long wavelength transmission, while the first region handles short wavelength transmission. This regional differentiation resolves the contradiction between achieving long wavelength transmission and maintaining spectral precision.
Solution Approach 2:
The patent utilizes parameter changes by varying the film thickness parameter across regions. The second region employs a greater film thickness parameter that narrows the peak width and half width of the transmission band, thereby improving detection accuracy for long wavelength light while maintaining the desired transmission characteristics.
3Reliability
If the film thickness is increased to improve sensitivity, then the sensitivity increases, but the peak width widens causing color mixture
Solution Approach 1:
The patent applies local quality by dividing the filter into regions with different thicknesses. The second region with greater thickness is optimized for sensitivity where color mixture is less critical, while the first region with thinner film maintains narrow bandwidth precision in regions where spectral separation is most important. This spatial differentiation of thickness resolves the contradiction between sensitivity and spectral precision.
Solution Approach 2:
The patent segments the filter into multiple regions with different thickness characteristics. By segmenting the filter structure into a first region with first thickness and a second region with second thickness, the patent allows each segment to independently optimize for either sensitivity or spectral precision depending on the specific wavelength range and application requirements, thereby resolving the contradiction between these two parameters.
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 approach enhances the detection accuracy of narrow band light by tailoring the filter characteristics to each pixel, reducing sensitivity loss and color mixture, thereby improving the overall performance of the imaging device.
Implementation Method 1
a spectral filter with at least one metal layer structured by a grating of traversing slots is known. Moreover, patent application publication US 2015/0029366 A1 describes a color filter array including a plurality of color filters having different center frequencies. International Patent Application Publication WO 2009/011439 A1 provides an optical filter that uses a localized surface plasmon.
Data Source
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AI summary
According to some aspects, an imaging device is provided comprising a photoelectric conversion layer configured to receive light and to produce an electric charge in response to the received light, including a first filter region corresponding to a first pixel of the imaging device, the first filter region having a first thickness and a plurality of through holes formed therein, wherein the first filter region transmits light incident on the first filter region with a first peak transmission wavelength, and a second filter region corresponding to a second pixel of the imaging device, the second filter region having a second thickness greater than the first thickness and having a plurality of through holes formed therein, wherein the second filter region transmits light incident on the second filter region with a second peak transmission wavelength that is greater than the first peak transmission wavelength.