Optocoupler Optical Cavity Reflective Layer High Voltage
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Solution Overview
Problem
State-of-the-art optocouplers experience a significant drop in current transfer ratio (CTR) at high voltage ratings above 10 KV due to inefficient optical coupling and packaging, leading to unacceptable performance.
Innovation Solution
The design includes a light source and detector enclosed in an optical cavity with a reflective layer, optimizing the placement of LEDs and photo-diodes to maintain high optical efficiency and axial uniformity, ensuring adequate CTR even at high voltages through the use of optically transparent and reflective materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the voltage rating of the optocoupler is increased, then the high voltage control capability is improved, but the current transfer ratio decreases
Solution Approach 1:
The patent applies local quality by creating a specialized optical cavity environment with controlled optical properties. The cavity includes a reflective layer at the bottom and optically transparent material, creating localized optical enhancement zones around the light source and light detector. This local optical optimization ensures sufficient light coupling efficiency even when the components are positioned far apart to achieve high voltage rating.
Solution Approach 2:
The patent implements nesting by placing the light source and light detector inside an enclosed optical cavity. The cavity structure contains and directs light between these nested components, with the reflective layer at the bottom creating multiple internal reflections. This nested configuration maximizes light utilization within the constrained space while maintaining the physical separation needed for high voltage isolation.
2Strength
If the distance between light source and light detector is increased, then the high voltage isolation is improved, but the optical coupling efficiency decreases
Solution Approach 1:
The patent transitions from one-dimensional direct light transmission to three-dimensional light propagation within the optical cavity. The reflective layer at the bottom of the cavity creates multiple reflection paths, allowing light to travel through multiple dimensions before reaching the light detector. This dimensional change enables effective light coupling even when the straight-line distance between components is large.
Solution Approach 2:
The patent ensures continuity of useful action by creating multiple light transmission paths through the reflective layer. Instead of relying on a single direct path that would be insufficient at large distances, the reflective layer continuously redirects light throughout the cavity, maintaining ongoing light interaction between the source and detector despite the increased separation distance.
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 enhances optical efficiency and axial uniformity, maintaining an adequate current transfer ratio at high voltages, preventing hot spots and ensuring sufficient current flow through the high voltage circuit.
Implementation Method 1
a reflective layer including optically reflective material surrounding the optical cavity
Implementation Method 2
an optical cavity including optically transparent material at least partially covering the body of the light source and the diode stack of the light detector
Implementation Method 3
a light detector having a diode stack
Data Source
AI summary
The present invention relates to an optocoupler including a light source having a body and electrical leads, a light detector having a diode stack a metal end cap and electrical leads, and an optical cavity including optically transparent material at least partially covering the body of the light source and the diode stack of the light detector. Also included is a reflective layer including optically reflective material surrounding the optical cavity. The electrical leads of the light source, the metal end cap and the electrical leads of the light detector protrude from the optical cavity and the reflective layer.