VCSEL Array Parallel Wiring for Voltage and Heat Management
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Solution Overview
Problem
Existing vertical cavity surface emitting laser arrays face challenges in achieving efficient heat dissipation and uniform light emission due to series connection of light emitting portions, which increases driving voltage and may result in voltage drops and reduced light uniformity.
Innovation Solution
The design includes a double mesa structure with a metal film-insulating film-metal structure for parallel connection of light emitting portions, allowing for low wiring resistance and efficient heat dissipation, and the use of a buffer layer to apply a negative potential for uniform light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If light emitting portions are connected in series, then the driving voltage increases, but the voltage drops and light uniformity deteriorate
Solution Approach 1:
The patent divides the light emitting portions into multiple independent units (first VCSEL array and second VCSEL array) that can be connected in parallel. Each array has its own electrode pads and metal layers, allowing independent current paths that prevent voltage drops and maintain uniform light emission across all portions.
2Power
If series connection is used, then the driving voltage increases, but the heat dissipation efficiency decreases
Solution Approach 1:
The patent segments the electrode structure into separate metal layers (first metal layer and second metal layer) that can be independently optimized for heat dissipation. The insulating film between layers allows thermal management while maintaining electrical isolation, enabling efficient heat dissipation in parallel-connected arrays.
Solution Approach 2:
The insulating film acts as an intermediary between the first and second metal layers, allowing thermal conduction while maintaining electrical isolation. This enables the metal layers to work together for heat dissipation without causing electrical short circuits.
3Power
If parallel connection with low wiring resistance is implemented, then the driving voltage decreases and heat dissipation improves, but the device structure becomes more complex
Solution Approach 1:
The patent merges multiple metal layers (first metal layer and second metal layer) to create a comprehensive wiring network that provides both low resistance current paths and heat dissipation channels. The electrode pads of different conductivity types are strategically positioned and connected through multiple layers, achieving low wiring resistance while managing the increased structural complexity through systematic integration.
Data Source
AI summary
A vertical cavity surface emitting laser array includes a contact layer formed on a substrate; mesa structures formed on the contact layer, each mesa structure including a first semiconductor multilayer reflector of a first conductivity type, an active region on the first semiconductor multilayer reflector, and a second semiconductor multilayer reflector of a second conductivity type on the active region; a first metal layer formed on the contact layer around the mesa structures, a portion of the first metal layer serving as an electrode pad of the first conductivity type; an insulating film formed on the first metal layer; and a second metal layer formed on the insulating film, a portion of the second metal layer serving as an electrode pad of the second conductivity type. The mesa structures are electrically connected in parallel.