Photocoupler with Nested Light Elements for Compact Mounting
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Solution Overview
Problem
Existing photocouplers face challenges in reducing size and mounting surface area, especially in applications like inverter air conditioners and integrated circuit testers, where a large number of devices are required, leading to operational errors due to direct coupling of different power supply systems.
Innovation Solution
A photocoupler design featuring a transparent support substrate with a semiconductor stacked body, a bonding layer that is both transparent and insulative, and a molded resin body covering the light emitting and receiving elements, which reduces the spread of emitted light and increases current efficiency while minimizing the mounting surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the photocoupler size is reduced to decrease mounting surface area, then the number of devices that can be mounted increases, but the light transmission efficiency decreases and current density reduces
Solution Approach 1:
The light receiving element is positioned within the projection area of the light emitting element, creating a nested configuration where the photodiode array is located inside the region where light is emitted. This allows the light receiving element to be efficiently positioned to receive light while minimizing the overall device footprint and mounting surface area.
Solution Approach 2:
The invention transitions from planar lateral arrangement to vertical stacking, with the light receiving element positioned beneath the light emitting element in the thickness direction. This dimensional change allows compact integration while maintaining effective light coupling between elements.
2Length of stationary object
If the photocoupler thickness is reduced, then the device becomes more compact, but the light transmission path is shortened and current density decreases
Solution Approach 1:
The light receiving element is nested within the projection area of the light emitting element, allowing the photodiode active area to be positioned optimally close to the light emitting surface without requiring increased device thickness. This nested configuration maximizes light capture efficiency within a compact thickness profile.
Solution Approach 2:
The invention changes the geometric parameters of the light receiving element, specifically making its area smaller than the light emitting element's projection area. This parameter optimization allows efficient light reception while maintaining compact device dimensions and adequate current density.
3Device complexity
If different power supply systems are directly coupled, then circuit complexity is reduced, but operation errors increase due to lack of insulation
Solution Approach 1:
The photocoupler acts as an intermediary device between different power supply systems, using optical transmission to transfer signals while maintaining electrical insulation. The light emitting element converts electrical signals to optical signals, which are then detected by the light receiving element, providing galvanic isolation while enabling signal transmission between isolated circuits.
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 design enhances current efficiency and reduces misoperations by efficiently transmitting electrical signals with reduced photocoupler thickness and surface area, suitable for applications like inverter air conditioners and integrated circuit testers.
Implementation Method 1
convert an input electrical signal into an optical signal by using a light emitting element
Implementation Method 2
an electrical signal can be output by a light receiving element after receiving the optical signal
Data Source
AI summary
According to one embodiment, a photocoupler includes a light emitting element, a light receiving element, a bonding layer, input terminals, output terminals and a molded resin body. A light emitting element includes a transparent support substrate, a semiconductor stacked body, and first and second electrodes. A light receiving element includes a light reception surface, a first electrode, and a second electrode. A bonding layer is configured to bond the first surface of the support substrate to the light reception surface side of the light receiving element. The bonding layer is transparent and insulative. Input terminals are connected to the first and second electrodes of the light emitting element. Output terminals are connected to the first and second electrodes of the light receiving element. The light reception surface is included in the light emitting surface. An input electrical signal is converted into an output electrical signal.