VCSEL Index-Contrast Grating Lens for Uniform Emission
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Solution Overview
Problem
Existing VCSEL-based light-emitting devices require complex and costly processes for precise positioning of diffusion lenses, which can lead to positioning errors and degrade the emission pattern, especially when aiming for high optical power and uniform angular distribution of light intensity.
Innovation Solution
A light-emitting device featuring a vertical-cavity surface-emitting laser (VCSEL) coupled with a planar diffusion lens formed by an index-contrast grating, which includes separate pads of a high refractive index surrounded by a low refractive index medium, arranged to provide rotational symmetry and minimize astigmatism, allowing for simpler and more precise fabrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a diffusion lens is positioned precisely using a complex six-axis adjustment process, then the emission pattern quality is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the VCSEL and diffusion lens into a single integrated structure where the lens is formed directly within the VCSEL device layer. This eliminates the need for separate lens positioning mechanisms and six-axis adjustment processes, while maintaining precise optical alignment through the integrated design.
Solution Approach 2:
The VCSEL structure itself provides the optical focusing function through its integrated diffusion lens, eliminating the need for external positioning systems. The lens is self-aligned within the VCSEL device, requiring no separate adjustment mechanisms.
2Manufacturing precision
If a diffusion lens is positioned with high precision, then the emission pattern is improved, but the manufacturing cost increases
Solution Approach 1:
The patent combines the VCSEL and diffusion lens into a single integrated device, eliminating the need for separate lens positioning and assembly steps. This integration simplifies the manufacturing process and reduces costs while maintaining precise optical performance.
Solution Approach 2:
The VCSEL structure inherently provides the diffusion lens function through its integrated design, eliminating the need for external lens components and their associated positioning and assembly costs.
3Manufacturing precision
If a diffusion lens is used to shape the light beam, then the emission pattern is improved, but positioning errors can occur degrading the pattern
Solution Approach 1:
The patent merges the VCSEL and diffusion lens into a single integrated structure, eliminating relative positioning errors between separate components. The lens is formed within the VCSEL device layer, ensuring fixed and reliable alignment.
Solution Approach 2:
The VCSEL structure itself provides the optical focusing function through its integrated diffusion lens, eliminating positioning errors that would occur with separate lens components.
4Power
If a VCSEL emits high optical power, then the light beam intensity is improved, but maintaining uniform angular distribution becomes more difficult
Solution Approach 1:
The patent implements a diffusion lens with spatially varying properties - the refractive index and lens curvature are optimized at different locations to achieve uniform angular distribution across the entire high-power light beam, while maintaining high optical power output.
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 enables a high-performance light-emitting device with a uniform angular distribution of light intensity and reduced astigmatism, achieving a desired emission pattern with improved precision and cost-effectiveness in the fabrication process.
Implementation Method 1
an index-contrast grating forming a diffusion lens, said grating being arranged on the emission surface and comprising a plurality of pads that are separate from one another and that are made of at least one material of a first refractive index, said pads being encircled by a medium of a second refractive index different from the first index
Data Source
AI summary
A light-emitting device includes a vertical-cavity surface-emitting laser, the resonant cavity of which is transverse multimode supporting transverse modes having rotational symmetry of order two about a main optical axis, and an index-contrast grating including a plurality of pads. The pads include: a central pad, a plurality of peripheral pads, which are periodically arranged along one or more lines that are concentric with respect to the central pad, and which are arranged so that the grating has, with respect to the main optical axis, a rotational symmetry of uneven order higher than or equal to three.