Substrate-Emitting SLED With 45-Degree Reflection
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Solution Overview
Problem
Conventional superluminescent light emitting diode (SLED) devices are complex and expensive to manufacture, and they often suffer from optical feedback and poor beam quality, limiting their efficiency and application in compact, cost-effective systems.
Innovation Solution
A substrate-emitting SLED device design that eliminates the need for wafer cleaving, incorporates a reflective element at a 45-degree angle to direct light vertically, and includes a un-pumped lateral beam expansion gap to minimize optical feedback, allowing for compact, cost-effective fabrication and integration with optically pumped lasers for enhanced functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional LD/SLED devices are used to achieve high optical power density, then the device complexity and manufacturing cost increase significantly
Solution Approach 1:
The device is segmented into distinct functional layers: a light source layer, a transparent substrate, and a reflective element layer. This segmentation allows each component to be optimized independently and fabricated using standard semiconductor processes, reducing overall device complexity while maintaining high optical power density.
Solution Approach 2:
The invention transitions from conventional edge-emitting LD/SLED geometry to a vertical cavity geometry where light propagates perpendicular to the substrate. This dimensional change enables the use of transparent substrates and planar reflective elements, simplifying fabrication and reducing device complexity.
2Power
If conventional LD/SLED devices are used to achieve high optical power density, then the manufacturing cost increases
Solution Approach 1:
By dividing the device into separate functional layers that can be fabricated using standard semiconductor processes, the invention enables mass production through wafer-scale fabrication. The transparent substrate and reflective elements can be manufactured independently and assembled, reducing overall manufacturing cost.
Solution Approach 2:
The planar structure of the transparent substrate and reflective elements allows for wafer-scale fabrication and copying of the device structure across multiple units simultaneously, significantly reducing per-unit manufacturing cost compared to conventional LD/SLED fabrication methods.
3Object-affected harmful factors
If conventional SLED devices are used to minimize optical feedback, then the beam quality deteriorates
Solution Approach 1:
The invention extracts and removes the harmful reflective interfaces present in conventional LD/SLED devices by using a transparent substrate that eliminates total internal reflection at the semiconductor-substrate interface. The reflective element is deliberately positioned and oriented to prevent feedback into the active region, thereby suppressing optical feedback while maintaining good beam quality.
Solution Approach 2:
The transparent substrate acts as an intermediary between the light source and the reflective element, controlling the optical path to prevent feedback while maintaining beam quality. The substrate's transparency and specific thickness are designed to optimize light extraction and minimize unwanted reflections.
4Ease of manufacture
If wafer cleaving is used in conventional LD/SLED fabrication, then the manufacturing process becomes complex and expensive
Solution Approach 1:
The device is designed with a transparent substrate that can be fabricated and assembled without requiring precision wafer cleaving. The segmented structure allows the substrate to be processed independently using standard semiconductor fabrication techniques, eliminating the need for precision mechanical cleaving operations.
Solution Approach 2:
The invention replaces the mechanical wafer cleaving process with a fabrication approach using transparent substrates that can be processed using standard semiconductor manufacturing techniques such as photolithography, etching, and deposition, thereby eliminating the need for precision mechanical cleaving.
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 the production of SLED devices with high optical power density and reduced optical feedback, facilitating low-cost fabrication and integration with optically pumped lasers, suitable for applications like compact RGB projectors and high-intensity light sources within limited étendu.
Implementation Method 1
a reflective element on a front surface of the substrate configured to reflect the optical beam and emit light via a back surface of the substrate in a substantially vertical direction to the substrate
Data Source
AI summary
The invention relates to a SLED device emitting light from a substrate side, configured to suppress lasing, and comprising a reflective element (55) on a front surface of a substrate (22) configured to redirect an optical beam (light) onto a back surface of the substrate (22). In one embodiment the device can be used for making a compact RGB (red-green-blue) projector.