VCSEL Light Source With Integrated Diffuser Feedback Control
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Solution Overview
Problem
Existing light sources with integrated diffusers, such as those using vertical cavity surface emitting lasers (VCSELs), face challenges in package-level integration and cost due to the separate inclusion of diffusers away from the optical source, which can affect uniformity and reliability.
Innovation Solution
An integrated light source configuration that includes a VCSEL with a diffuser and monitor photodetector on the same substrate, where the diffuser is positioned on the bottom surface and the monitor photodetector receives reflected light to monitor and control the optical signal, allowing for real-time feedback and automatic adjustment of the light source operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the diffuser is included in a package at some distance away from the optical source, then the light source can be simpler to manufacture, but the uniformity and reliability of the light source deteriorates
Solution Approach 1:
The patent integrates the diffuser and monitor photodetector directly with the VCSEL on the same substrate, eliminating the need for separate package-level integration. This merging of components improves reliability and uniformity while maintaining manufacturability through monolithic fabrication processes.
2Device complexity
If the diffuser is included in a package at some distance away from the optical source, then the device complexity is reduced, but the uniformity of the light profile deteriorates
Solution Approach 1:
By integrating the diffuser directly with the VCSEL on the same substrate, the patent ensures precise alignment and uniform light distribution. The monolithic integration eliminates misalignment issues that would occur with separate package-level components, thereby improving uniformity without significantly increasing device complexity.
Solution Approach 2:
The diffuser is positioned specifically on the substrate near the VCSEL to optimize light distribution in the critical region where uniformity is most needed. This localized approach ensures high manufacturing precision in the active area while keeping the overall device structure relatively simple.
3Reliability
If the monitor photodetector is integrated with the VCSEL on the same substrate, then the reliability and uniformity are improved, but the device complexity increases
Solution Approach 1:
The monitor photodetector is integrated with the VCSEL on the same substrate, allowing for real-time monitoring of the light output. This integration improves reliability by enabling feedback control while the monolithic fabrication process keeps the manufacturing process relatively simple, offsetting the increased device complexity.
Solution Approach 2:
The integrated monitor photodetector provides real-time feedback on the light output from the VCSEL, enabling automatic power control and alignment monitoring. This feedback mechanism improves reliability by allowing the system to self-correct for drift or malfunction, justifying the increased device complexity through enhanced performance and safety.
4Object-affected harmful factors
If real-time monitoring and automatic power control are implemented, then eye safety is improved, but the device complexity and cost increase
Solution Approach 1:
The integrated monitor photodetector provides real-time feedback on the light output, enabling automatic power control to prevent eye damage. This feedback system continuously monitors the VCSEL output and adjusts power levels to maintain safe operation, significantly improving eye safety despite the increased device complexity.
Solution Approach 2:
The system uses the integrated monitor photodetector to self-monitor and self-regulate the VCSEL output power, automatically adjusting to maintain safe operating levels. This self-service capability improves eye safety without requiring external monitoring equipment, partially offsetting the increased device complexity through integrated functionality.
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 reliability and uniformity of the light source by integrating the diffuser and monitor photodetector with the VCSEL, reducing costs and improving eye safety by enabling real-time monitoring and automatic power control to prevent potential eye damage from misalignment or malfunction.
Implementation Method 1
a light generator in the epitaxial layer positioned such that an optical signal transmitted is directed toward the substrate
Implementation Method 2
The diffuser may control divergence of the profile of the light source
Implementation Method 3
at least one monitor photodetector in the epitaxial layer is positioned to receive a portion of the optical signal which is reflected by the diffuser
Implementation Method 4
at least one monitor photodetector in the epitaxial layer is positioned to receive a portion of the optical signal which is reflected by the diffuser
Data Source
AI summary
A light source includes a substrate with a first surface and an opposite second surface. An epitaxial layer is positioned on the first surface of the substrate. The light source also includes at least one light generator in the epitaxial layer positioned such that an optical signal transmitted thereby is directed toward the substrate. A diffuser is positioned on the second surface of the substrate, and at least one monitor photodetector is positioned in the epitaxial layer in an arrangement configured to receive a portion of the optical signal which is reflected by the diffuser. In one form, the light generator may include a vertical cavity surface emitting laser (VCSEL).