Planar Optical Filter with Bragg Layers for Compact Spectrometers
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Solution Overview
Problem
Conventional spectrometers are bulky and heavy due to their separate optical components, necessitating a more compact design for integration with semiconductor chips.
Innovation Solution
The development of optical filters with multiple Bragg reflective layers and multi-layers having different refractive indices and thicknesses, allowing for a compact arrangement that reduces the size of spectrometers by filtering specific wavelength bands effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional spectrometers use separate optical components, then spectroscopic performance is maintained, but device size and weight increase
Solution Approach 1:
The patent combines multiple optical components (bandpass filters, multi-layers, and sensors) into a single integrated optical filter assembly. The bandpass filters are positioned in direct contact with or close to the sensor array, eliminating the need for separate mounting structures and reducing overall device volume while maintaining spectroscopic functionality.
Solution Approach 2:
The optical filter assembly serves multiple functions simultaneously: the bandpass filters perform wavelength selection, the multi-layers provide structural support and additional optical filtering, and the entire assembly acts as a compact spectroscopic device. This multi-functionality reduces the number of separate components needed, thereby reducing device complexity.
2Device complexity
If multiple filter elements are arranged on the same plane, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
Multiple filter elements are combined into a single planar array structure where each filter element corresponds to a specific sensor element. This integrated arrangement simplifies the overall device structure compared to stacked or separate component configurations, reducing device complexity despite the precision required for alignment.
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 solution enables a more compact spectrometer design by efficiently filtering specific wavelength bands, enhancing the device's portability and integration capabilities while maintaining effective spectroscopic performance.
Implementation Method 1
a first bandpass filter including a plurality of first Bragg reflective layers and at least one first cavity provided between the plurality of first Bragg reflective layers
Implementation Method 2
the first multi-layer having a different center wavelength than the first center wavelength of the plurality of first Bragg reflective layers to block light of other wavelength bands than the first wavelength band
Data Source
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AI summary
Provided are an optical filter and a spectrometer including the optical filter. The optical filter includes at least one first filter element having a first center wavelength of a first wavelength band, and at least one second filter element arranged on a same plane as the at least one first filter element, the at least one second filter element having a second center wavelength of a second wavelength band. The at least one first filter element includes a first bandpass filter including a plurality of first Bragg reflective layers and at least one first cavity provided between the plurality of first Bragg reflective layers, and a first multi-layer provided on the first bandpass filter, the first multi-layer having a center wavelength different than the first center wavelength of the first Bragg reflective layers in order to block light of a wavelength band other than the first wavelength band.