Integrated VCSEL Array Diffuser for Directed Beam Steering
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Solution Overview
Problem
Conventional external diffusers for VCSEL arrays suffer from inefficiencies due to divergence issues, reflection problems, and difficulty in integration with VCSEL arrays, leading to sub-optimal performance in applications like 3D sensing.
Innovation Solution
A bottom-emitting VCSEL array with an integrated optical element featuring a plurality of lens segments that steer beams to specific angles, creating a diffusion pattern without spreading light over the entire field-of-view, thereby mimicking the output of a conventional diffuser but with improved efficiency and compact integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an external diffuser is used with a VCSEL array, then light is spread over the entire field-of-view, but the system suffers from divergence issues and reflection problems leading to sub-optimal performance
Solution Approach 1:
The patent merges the VCSEL array and diffuser into a single integrated device where the diffuser is formed directly on the VCSEL array substrate. This integration eliminates the external diffuser arrangement, reducing reflection problems and divergence issues while improving overall optical system performance and reliability.
Solution Approach 2:
The diffuser is nested within the VCSEL array structure itself, formed as a layer on the substrate. This nested configuration allows the diffuser to be embedded within the device architecture rather than being an external component, thereby improving integration and reducing optical losses.
2Ease of operation
If a conventional external diffuser is used, then light diffusion is achieved, but the diffuser spreads light from a given VCSEL over the entire FOV without emitter-to-emitter differentiation
Solution Approach 1:
The diffuser is segmented into multiple regions corresponding to different VCSEL emitters. Each segment diffuses light from its associated VCSEL into a specific angular range rather than spreading it over the entire FOV. This segmentation enables independent illumination of different regions and improves FOV efficiency by directing light more precisely.
Solution Approach 2:
Different segments of the diffuser have different optical properties tailored to their specific VCSEL emitters. Each segment is designed with specific characteristics to control the diffusion pattern of its corresponding emitter, enabling localized optimization of light distribution and improving overall system efficiency.
3Productivity
If an integrated optical element with lens segments is used, then beam steering to specific angles is achieved, but the device structure becomes more complex
Solution Approach 1:
The lens segments are merged with the diffuser structure, forming an integrated optical element where focusing and diffusion functions are combined in a single component. This integration achieves efficient beam steering to specific angles while avoiding the complexity of separate lens and diffuser components.
Solution Approach 2:
The integrated optical element performs multiple functions simultaneously: it acts as both a diffuser to spread light and a lens to steer beams to specific angles. This multi-functionality improves illumination efficiency while reducing the number of separate components needed in the system.
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 integrated optical element enhances the efficiency of the optical system, allows independent illumination of different regions, and achieves a 'bat-wing' profile with higher intensity at larger angles, improving FOV efficiency and reducing the appearance of speckle patterns.
Implementation Method 1
a surface of a first lens segment of the plurality of lens segments is sloped to cause a beam from a first VCSEL of the plurality of VCSELs to be steered at a first angle
Data Source
AI summary
A bottom-emitting vertical-cavity surface-emitting laser (VCSEL) chip may include a VCSEL array including plurality of VCSELs and an integrated optical element including a plurality of lens segments. The integrated optical element may direct beams provided by the plurality of VCSELs to a particular range of angles to create a diffusion pattern using the beams provided by the plurality of VCSELs. A surface of a first lens segment may be sloped to cause a beam from a first VCSEL to be steered at a first angle and a surface of a second (adjacent) lens segment may be sloped to cause a beam from a second VCSEL to be steered at a second angle. A direction of the second angle with respect to a surface of the VCSEL array may be opposite to a direction of the first angle with respect to the surface of the VCSEL array.