Photodetector Module Impedance Matching via Dielectric Plate
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Solution Overview
Problem
Conventional photodetector modules achieve impedance matching but fail to consider power saving, necessitating a solution that balances impedance matching with low power consumption.
Innovation Solution
A photodetector module with a high impedance amplifier and a dielectric plate between the amplifier and substrate, where the dielectric plate cancels the capacitance component of the amplifier's output to achieve impedance matching and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional amplifier with matched impedance is used, then impedance matching with the substrate is achieved, but power consumption increases
Solution Approach 1:
The invention changes the output impedance parameter of the amplifier from conventional matched impedance to high impedance (higher than matched impedance). This parameter change enables the amplifier to consume less power while the dielectric layer compensates for the impedance mismatch through its specific thickness and dielectric constant, ultimately achieving both low power consumption and impedance matching with the substrate.
Solution Approach 2:
The dielectric layer acts as an intermediary between the high-impedance amplifier and the substrate. It mediates the impedance transformation by introducing a capacitance effect that cancels the amplifier's output capacitance, enabling the high-impedance amplifier to interface properly with the substrate without requiring conventional low-impedance design.
2Use of energy by moving object
If the output impedance of the amplifier is increased to reduce power consumption, then power saving is achieved, but impedance matching with the substrate is lost
Solution Approach 1:
The invention changes the output impedance parameter of the amplifier from conventional matched impedance to high impedance (higher than matched impedance). This parameter change enables the amplifier to consume less power while the dielectric layer compensates for the impedance mismatch through its specific thickness and dielectric constant, ultimately achieving both low power consumption and impedance matching with the substrate.
Solution Approach 2:
The dielectric layer acts as an intermediary between the high-impedance amplifier and the substrate. It mediates the impedance transformation by introducing a capacitance effect that cancels the amplifier's output capacitance, enabling the high-impedance amplifier to interface properly with the substrate without requiring conventional low-impedance design.
3Speed
If a metal sleeve is added to form a coaxial line to improve high-frequency response, then inductance component is reduced, but device complexity increases
Solution Approach 1:
The dielectric layer serves multiple functions simultaneously: it provides electrical insulation between the amplifier and substrate, introduces capacitance to cancel the amplifier's output capacitance for impedance matching, and maintains a compact structure without requiring additional metal sleeves or coaxial configurations. This multi-functionality achieves high-frequency response improvement without increasing structural complexity.
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 impedance matching with the substrate while reducing power consumption by using a high impedance amplifier and a dielectric plate to cancel capacitance, effectively addressing the power-saving requirement.
Implementation Method 1
thickness of the dielectric in a direction from the board to the substrate is such that an inductance component of the lead pin includes an inductance component canceling the capacitance component of the amplifier
Implementation Method 2
an inductance component of the lead pin includes an inductance component canceling the capacitance component of the amplifier
Data Source
Figure 1
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AI summary
A photodetector module that can achieve impedance matching and power saving. A photodetector (11) and an amplifier (12) for amplifying an electric signal from the photodetector (11) are mounted on a stem (14). A dielectric plate (18) is arranged between the stem (14) and a flexible substrate (20). To transfer an electric signal from the amplifier (12) to the substrate (20), a lead pin (15d) is provided to pass through the stem (14) and the dielectric plate (18). The output of the amplifier (12) includes a capacitance component, and the output impedance of the amplifier (12) is higher than the impedance that matches with the substrate (20). Further, the thickness d of the dielectric plate (18) is such that the inductance component of the lead pin (15d) includes an inductance component that is inductive, which cancels the capacitance component of the amplifier, and impedance matching with the substrate (20) can be achieved.