VCSEL Electrode Layout for Uniform LIDAR Emission
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Solution Overview
Problem
Conventional laser emitters in LIDAR systems suffer from nonuniform luminous intensity due to parasitic resistance and inductance caused by the location of electrode units within the light emission path, leading to reduced drive signal transmission and brightness variation across light-emitting points.
Innovation Solution
The electrode units are positioned on a side of the reflector away from the active region, allowing for a larger effective width and reducing parasitic parameters, with drive signals transmitted through multiple drive ends and solder balls to improve uniformity, and the use of a microlens structure for enhanced light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrode units are located within the light emission path, then the light emitting unit can be driven, but parasitic resistance and inductance increase causing nonuniform luminous intensity
Solution Approach 1:
The electrode units are extracted from the light emission path and relocated to the side of the first reflector away from the active region. This separation removes the source of parasitic resistance and inductance from the optical path, eliminating the cause of nonuniform luminous intensity while preserving the drive signal transmission function through alternative routing via bonding pads and interconnect structures.
2Illumination intensity
If electrode units are moved to the side of the first reflector, then luminous intensity uniformity improves, but drive signal transmission path becomes more complex
Solution Approach 1:
The electrode units are relocated from the vertical light emission dimension to the lateral dimension on the reflector side. This dimensional shift allows the drive signal transmission path to extend laterally through bonding pads and interconnect structures rather than vertically through the light path, resolving the conflict between uniformity improvement and transmission complexity by utilizing spatial reconfiguration.
3Illumination intensity
If multiple drive ends are used to load drive signals, then uniformity of luminous intensity improves, but manufacturing precision requirements increase
Solution Approach 1:
Multiple drive ends are implemented at different locations on the electrode units, with each drive end having bonding pads positioned to optimize local signal distribution. This local quality approach ensures that drive signals are loaded uniformly across different regions of the light-emitting stack, compensating for variations in parasitic parameters at different locations and achieving overall luminous intensity uniformity.
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 the transmission capacity of drive signals and achieves improved uniformity of luminous intensity across the laser emitter, leading to more accurate and consistent light detection in LIDAR applications.
Implementation Method 1
a vertical-cavity surface-emitting laser (VCSEL)... including a first reflector, an active region, and a second reflector sequentially arranged in a light emission direction
Data Source
AI summary
A laser device, a light source module and a laser radar. The laser device comprises: a light-emitting lamination, comprising a first reflector (105), an active region (104) and a second reflector (102), which are sequentially arranged in a light emergence direction, wherein the light-emitting lamination comprises one or more light-emitting units (200), and each of the light-emitting units (200) comprises a plurality of regularly arranged light-emitting points (203); and electrode units (107) located on the side of the first reflector (105) that is away from the active region (104), wherein each of the electrode units (107) corresponds to one light-emitting unit (200) and is used for loading a driving signal to the light-emitting unit (200). The laser device can improve the uniformity of luminous intensity.