VCSEL Sub-Array Electrode Layout for Compact Low-Current Arrays
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Solution Overview
Problem
Conventional VCSEL arrays lack miniaturization capabilities, which limits their performance and integration in applications such as LiDAR devices.
Innovation Solution
A surface-emitting laser array configuration where sub-arrays of VCSEL devices are electrically connected in parallel and series through electrodes, reducing the drive current and enabling miniaturization by eliminating the need for separate anode and cathode pads, and allowing closer spacing of light-emitting units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If VCSEL devices are electrically connected in series to reduce driving current, then energy consumption is reduced, but device complexity increases due to additional electrode connections
Solution Approach 1:
The patent merges the electrical connection function into the substrate structure itself. The substrate includes conductive regions that automatically electrically connect adjacent VCSEL devices in series, eliminating the need for separate external wiring. This combining of the connection function into the substrate resolves the contradiction by reducing driving current while avoiding additional complexity from external electrode structures.
Solution Approach 2:
The substrate is designed to automatically provide electrical connections between VCSEL devices through its inherent conductive structure. The series connection is achieved self-service through the substrate's conductive regions that naturally connect adjacent devices without requiring external wiring or additional connection components, thus reducing energy consumption without increasing device complexity.
2Ease of manufacture
If separate anode and cathode pads are provided for each VCSEL device, then ease of manufacture is improved, but area of the device increases preventing miniaturization
Solution Approach 1:
The patent merges the pad functions of multiple VCSEL devices into shared conductive regions within the substrate. Instead of providing separate anode and cathode pads for each device, the substrate contains common conductive regions that serve multiple devices simultaneously. This merging approach maintains ease of manufacture through standard fabrication processes while dramatically reducing the total device area by eliminating redundant pad structures.
Solution Approach 2:
The substrate's conductive regions are designed to serve multiple functions: they act as electrical connections for multiple VCSEL devices, provide mechanical support, and serve as common pads for adjacent devices. This multi-functionality allows the same structural elements to fulfill multiple roles, achieving miniaturization without compromising ease of manufacture.
3Area of moving object
If light-emitting units are spaced closer together for miniaturization, then area is reduced, but reliability decreases due to increased risk of short circuits
Solution Approach 1:
The substrate acts as an intermediary structure that provides controlled electrical connections between adjacent VCSEL devices. The conductive regions within the substrate are designed with specific geometries and isolation structures that prevent unintended short circuits while enabling necessary electrical connections. This intermediary substrate structure allows light-emitting units to be spaced closer together for miniaturization while maintaining reliability through controlled electrical pathways.
Solution Approach 2:
The substrate employs local quality variations in its conductive regions, with different areas having different electrical properties. Isolation structures and conductive patterns are locally optimized to prevent short circuits in critical areas while enabling connections where needed. This local differentiation allows close spacing of light-emitting units without compromising reliability, as each local region is designed with appropriate electrical characteristics.
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 solution achieves miniaturization of VCSEL arrays, reducing drive current and preventing uneven light emission, while allowing for efficient heat dissipation and preventing short circuits, thereby enhancing the performance and integration of VCSEL arrays in devices like LiDAR.
Implementation Method 1
a plurality of surface-emitting laser devices electrically connected to each other in parallel to emit light through the substrate
Implementation Method 2
an electrode configured to electrically connect the first semi-conducting layer in the plurality of surface-emitting laser devices included in one of the plurality of sub-arrays and the second semi-conducting layer in the plurality of surface-emitting laser devices included in another one of the plurality of sub-arrays
Data Source
AI summary
A surface-emitting laser array includes a substrate and a sub-arrays disposed on the substrate, the sub-arrays including a surface-emitting laser devices electrically connected to each other in parallel to emit light through the substrate, each of the surface-emitting laser devices having a light-emitting point and including a first semi-conducting layer of first conductivity. The laser array further includes a second semi-conducting layer of second conductivity, and a resonator disposed between the first semi-conducting layer and the second semi-conducting layer. The sub-arrays adjacent to each other include an electrode to electrically connect the first semi-conducting layer in the surface-emitting laser devices included in one of the sub-arrays and the second semi-conducting layer.