Signal Coupling Device Silicone Gel Encapsulation
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Solution Overview
Problem
Optical coupling devices experience gain variations due to environmental and operational stresses, particularly in high-temperature and high-humidity conditions, as the transmission chip is not adequately protected by encapsulating resins, leading to uneven stress distribution and offset voltages in operational amplifiers.
Innovation Solution
The use of silicone gel encapsulating resins with specific hardness values (10 to 24) to cover the transmission chip, reception chip, and light-emitting element, ensuring uniform stress distribution and maintaining the intended shape, while the outer resin shields external light and has a higher opacity to prevent signal interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the transmission chip is not covered with encapsulating resin, then the device structure is simpler, but the gain varies due to uneven stress distribution under high-temperature and high-humidity conditions
Solution Approach 1:
The encapsulation is divided into multiple segments: first encapsulating resin covering the transmission chip, second encapsulating resin covering the reception chip, and third encapsulating resin covering the light-emitting element. This segmented approach allows each component to be independently protected and stress-distributed, resolving the contradiction by providing comprehensive protection without excessive structural complexity.
Solution Approach 2:
Different regions of the device receive different encapsulation treatments tailored to their specific needs. The transmission chip, reception chip, and light-emitting element each have their own encapsulating resin layers with optimized properties, allowing local stress distribution and protection while maintaining overall device simplicity.
2Reliability
If silicone gel with specific hardness (10 to 24) is used to cover all components, then stress distribution is uniform and gain stability is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent specifies a particular hardness range (10 to 24) for the silicone gel encapsulating resin, which optimizes the balance between stress distribution and manufacturability. This parameter control ensures uniform stress distribution for gain stability while keeping the material properties within a manufacturable range.
3Object-affected harmful factors
If the outer resin is made opaque to shield external light, then signal interference is prevented, but the aesthetic appearance and light transmission for inspection are reduced
Solution Approach 1:
The outer resin is made opaque only in the specific region where light shielding is needed to prevent external light from reaching the photodetector. Other regions of the package may remain transparent or translucent, allowing for aesthetic considerations and inspection capabilities while maintaining the necessary light blocking function where critical.
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 approach mitigates stress-induced gain variations in optical coupling devices, maintaining stable operational balance and preventing peeling-off issues, even under accelerated life tests like the pressure cooker test, by dispersing stress uniformly across the silicone gel materials.
Implementation Method 1
a light-emitting element disposed on a first frame portion and configured to emit light
Implementation Method 2
a second semiconductor element disposed on a third frame portion and configured to receive the optical signal from the light-emitting element and to convert the optical signal into an electrical signal
Implementation Method 3
A first silicone gel is disposed on the second frame portion and covers the first semiconductor element
Implementation Method 4
A third silicone gel is disposed on the first frame portion and covers the light-emitting element
Implementation Method 5
the outer resin shields external light and has a higher opacity to prevent signal interference
Data Source
AI summary
A signal coupling device includes a first element to output a signal, and a second element to receive the signal. A first silicone gel covers the first element. A second silicone gel covers the second element. A stacked body comprising at least one of an insulated coil or a capacitor is provided. The first element, the second element, and the stacked body are encapsulated in resin material, which contacts the first and second silicone gels.