VCSEL Electrode Layout for High-Speed Independent Emitter Switching
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Solution Overview
Problem
The existing configuration of light emitting elements, such as VCSELs, requires multiple integrated circuits for controlling light emission switching, leading to increased size and cost, and limits switching speed due to IC performance constraints.
Innovation Solution
A light emitting element with a conductive substrate, DBR layers, and tunnel junction layers, where light emission units are separated and each has a distinct electrode configuration, allowing for independent control and high-speed switching without the need for additional switching ICs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple integrated circuits are used to control light emission switching, then light emission switching can be achieved, but device size and cost increase
Solution Approach 1:
The patent merges the control function for multiple light emission units into a single integrated circuit. The IC includes a plurality of emitter control circuits that can independently control multiple emitters, eliminating the need for separate ICs for each emitter or emitter group. This consolidation reduces device size and component count while maintaining independent control capability.
Solution Approach 2:
The integrated circuit is designed with multi-functional emitter control circuits that can control different groups of emitters with different duty cycles. Each control circuit within the IC can independently modulate light emission for its assigned emitters, providing universal control functionality across multiple light emission units without requiring multiple dedicated ICs.
2Ease of operation
If multiple integrated circuits are used to control light emission switching, then light emission switching can be achieved, but device cost increases
Solution Approach 1:
The patent merges the control function for multiple light emission units into a single integrated circuit. The IC includes a plurality of emitter control circuits that can independently control multiple emitters, eliminating the need for separate ICs for each emitter or emitter group. This consolidation reduces device size and component count while maintaining independent control capability.
3Ease of manufacture
If conventional electrode configuration is used with anode and cathode on the same plane, then manufacturing is simplified, but switching speed is limited by IC performance
Solution Approach 1:
The patent transitions from a planar electrode configuration to a three-dimensional stacked configuration. The anode and cathode electrodes are positioned on opposite sides of the semiconductor layer, utilizing the vertical dimension. This spatial rearrangement enables direct current injection from substrate to electrode without requiring lateral routing through limiting IC structures, thereby achieving higher switching speeds.
4Quantity of substance
If the number of light emission units is increased, then measurement capability is improved, but emitter interval decreases leading to manufacturing difficulties
Solution Approach 1:
The patent arranges multiple light emission units in a vertical stack along the optical axis rather than spreading them horizontally. This vertical configuration allows numerous emitters to be positioned in close proximity without reducing the horizontal emitter interval, enabling high-density emitter arrays while maintaining manufacturable spacing between adjacent emitters.
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 reduces the complexity and cost of the device, enabling faster switching speeds and reducing the emitter interval, while avoiding the limitations of having anode and cathode electrodes on the same plane.
Implementation Method 1
a tunnel junction layer is provided between the second main surface of the conductive substrate and the first main surface of the first DBR layer
Implementation Method 2
a first DBR layer provided on a side of the second main surface of the conductive substrate... a second DBR layer laminated on the first DBR layer
Data Source
AI summary
For example, a light emitting element capable of increasing a speed at which light emission of light emission units is switched is provided. The light emitting element includes: a conductive substrate having a first main surface and a second main surface opposite to the first main surface; a first electrode provided on the first main surface of the conductive substrate; a first DBR layer provided on a side of the second main surface of the conductive substrate and having a first main surface; at least two light emission units provided on a side opposite to the first main surface of the first DBR layer, in which a tunnel junction layer is provided between the second main surface of the conductive substrate and the first main surface of the first DBR layer, and each of the light emission units is separated from each other; a second DBR layer laminated on the first DBR layer and having a first main surface and a second main surface opposite to the first main surface; and a second electrode provided on a side of the second main surface of the second DBR layer.