Integrated Optical Coupler for Signal Switching
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Solution Overview
Problem
The use of multiple photorelays in measuring instruments increases the total installation area, and current leakage between high-frequency and low-frequency signal photorelays through external wiring affects their characteristics, particularly due to capacitive coupling between terminals.
Innovation Solution
An optical coupling device with integrated photorelays on a single substrate, where a common terminal connects the drains of MOS transistors, reducing unnecessary space and minimizing capacitive coupling between terminals, thereby reducing high-frequency leakage currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple photorelays are used for signal switching in measuring instruments, then the signal switching capability is improved, but the total installation area increases
Solution Approach 1:
The patent combines multiple photorelays (first photorelay for high-frequency signals and second photorelay for low-frequency signals) into a single integrated device mounted on one substrate. The light-receiving elements, transistors, and terminals are integrated on the same substrate, eliminating the need for separate devices and reducing total installation area while maintaining multiple signal switching capabilities.
2Device complexity
If photorelays are electrically connected by external wiring, then the device complexity is reduced, but current leakage occurs between high-frequency and low-frequency signal paths
Solution Approach 1:
The patent integrates all electrical connections within a single substrate, eliminating external wiring between photorelays. The common terminal and internally connected transistor drains remove the need for external wiring, thereby eliminating the capacitive coupling and current leakage issues that would occur with external connections.
Solution Approach 2:
The patent introduces a common terminal as an intermediary element that properly connects the drain of the first transistor to the drain of the second transistor within the substrate. This internal common terminal structure serves as a controlled intermediary that prevents unwanted capacitive coupling while maintaining necessary electrical connections, unlike external wiring which creates uncontrolled coupling.
3Area of stationary object
If photorelays are integrated on a single substrate, then the installation area is reduced, but the manufacturing complexity increases
Solution Approach 1:
The patent integrates multiple functional elements (light-receiving elements, MOS transistors, terminals, and interconnections) onto a single substrate using standard semiconductor fabrication techniques. This unified structure, while integrating multiple functions, uses conventional manufacturing processes that balance manufacturing complexity with the benefit of reduced installation area.
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 configuration allows for size reduction of photorelays without increasing high-frequency leakage currents, enhancing the reliability and performance of signal switching in measuring instruments by eliminating unnecessary space and reducing capacitive coupling.
Implementation Method 1
a light-emitting element (11), a light-receiving element (12) facing the light-emitting element (11)
Implementation Method 2
a light-emitting element (11), a light-receiving element (12) facing the light-emitting element (11)
Data Source
AI summary
An optical coupler device includes, on a substrate, a first light-receiving element coupled to a first light-emitting element and a second light-receiving element coupled to a second light-emitting element. First, second, and third terminals are disposed on the first substrate. A first transistor pair and a second transistor pair are disposed on the first substrate. The first transistor pair is configured to electrically connect and disconnect the first and second terminals in response to a first light signal received by the first light-receiving element. The second transistor pair is configured to electrically connect and disconnect the second and third terminals in response to a second light signal received by the second light-receiving element.