Fabry-Perot Filter Ground Path for Low-Crosstalk Light Detection
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Solution Overview
Problem
Existing light detection devices with integrated Fabry-Perot interference filters and light detectors face challenges in effectively curbing crosstalk noise due to proximity, which is exacerbated by current components flowing through support members and mounting substrates.
Innovation Solution
A light detection device design that separates the Fabry-Perot interference filter and light detector using spacers, incorporating a support member and a ground connection with a second current path of lower electrical resistance to divert current components away from the light detector, and includes a conductive connecting member to release current to ground potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the Fabry-Perot interference filter and light detector are integrally formed in proximity, then device compactness is improved, but crosstalk noise in detection signal increases
Solution Approach 1:
The patent introduces a support member (spacer) as an intermediary component between the Fabry-Perot interference filter and the light detector. This spacer physically separates the two components, increasing the distance between them and thereby reducing the crosstalk noise in the detection signal while maintaining a relatively compact overall device structure.
Solution Approach 2:
The patent extracts the light detector from immediate proximity to the Fabry-Perot interference filter by mounting it on a separate support member. This separation removes the harmful electromagnetic interference (crosstalk noise) from the detection signal while preserving the functional integration of the device.
2Object-affected harmful factors
If a support member is used to separate the Fabry-Perot interference filter and light detector, then crosstalk noise from proximity is reduced, but current components may flow through the support member and mounting substrate to the light detector
Solution Approach 1:
The patent converts the potentially harmful current flow through the support member into a beneficial path by providing a dedicated ground connection. The support member, which initially might conduct noise current to the detector, is now intentionally connected to ground, transforming it into a noise sink that actively drains unwanted current away from the detection circuit.
Solution Approach 2:
The patent applies preliminary anti-action by proactively providing a ground connection path before noise current can flow to the detector. The ground connection is established in advance through the support member, creating a preferred low-resistance path that prevents noise current from reaching the light detector in the first place.
3Object-affected harmful factors
If the distance between Fabry-Perot interference filter and light detector is increased, then crosstalk noise is reduced, but device size increases
Solution Approach 1:
The patent utilizes the vertical dimension (z-axis) to increase the separation distance between the Fabry-Perot interference filter and the light detector. By mounting the detector on a support member that extends perpendicular to the filter plane, the design achieves effective noise isolation through increased distance without significantly expanding the device's planar footprint.
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
Effectively reduces crosstalk noise in detection signals by increasing the distance between the Fabry-Perot interference filter and light detector, minimizing current flow to the detector, and reducing parasitic capacitance, thereby improving signal response speed.
Implementation Method 1
a Fabry-Perot interference filter in which a distance between a pair of mirror parts changes due to an electrostatic force
Implementation Method 2
a second current path having a smaller electrical resistance than that of an arbitrary first current path extending from the Fabry-Perot interference filter to the light detector via the support member and the mounting substrate is formed between the Fabry-Perot interference filter and the ground part
Data Source
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AI summary
A spectroscopic sensor includes a wiring substrate having a main surface, a light detector disposed on the main surface of the wiring substrate, a Fabry-Perot interference filter, a spacer which is provided on the main surface of the wiring substrate and supports the Fabry-Perot interference filter so that the Fabry-Perot interference filter and the light detector are separated from each other, and a stem connected to a ground potential. A second current path which has a smaller electric resistance than that of an arbitrary first current path which extends from the Fabry-Perot interference filter to the light detector via the spacer and the wiring substrate is formed between the Fabry-Perot interference filter and the stem.