Surface Mount Reflector Redirects Top-Emitting LED Radiation
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Solution Overview
Problem
Side-emitting LEDs are complex, expensive, and difficult to mount, with thermal limitations that prevent them from achieving the output levels of top-emitting diodes, and they have a taller package profile, making them less suitable for cost-effective and high-output applications.
Innovation Solution
A top-emitting diode assembly with a surface mountable reflector that redirects radiation emitted from the top and side surfaces of the diode towards an open end of the reflector in a direction parallel to the circuit substrate, simulating side-emission at a lower cost and higher output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If side-emitting LEDs are used to achieve higher collimating property and better modulation bandwidth, then optical communication performance is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent creates an optical copy of side-emitting LED performance using a top-emitting LED combined with a reflector structure. The reflector redirects light from the top-emitting LED to simulate the emission pattern of a side-emitting LED, achieving similar optical communication performance without the complexity of actual side-emitting diode structures
Solution Approach 2:
The reflector acts as an intermediary element that transforms the emission pattern of a top-emitting LED into a side-emitting pattern. By introducing this intermediate component, the system achieves side-emitting characteristics through a different physical mechanism, avoiding the need to manufacture complex side-emitting LED structures
2Reliability
If side-emitting LEDs are used to achieve higher collimating property, then coupling efficiency with optical waveguides is improved, but manufacturing cost increases
Solution Approach 1:
The reflector structure creates a simulated side-emitting pattern from a top-emitting LED, copying the functional characteristics of side-emitting LEDs that provide better coupling efficiency, while using standard top-emitting LED components that are cheaper and easier to manufacture
Solution Approach 2:
Instead of making the LED emit from the side directly, the patent inverts the approach by having the LED emit from the top and then using a reflector to redirect the light sideways. This inversion allows use of simpler, cheaper top-emitting LED technology while achieving the desired side-emission pattern for better waveguide coupling
3Ease of manufacture
If top-emitting diodes are used to reduce manufacturing cost, then ease of manufacture is improved, but output level is limited by thermal constraints
Solution Approach 1:
The reflector structure changes the spatial dimension of light emission by redirecting vertically emitted light from the top-emitting LED into a horizontal emission pattern. This dimensional transformation allows the LED to operate in a more favorable thermal regime while still achieving the side-emission pattern needed for high output performance
4Reliability
If side-emitting diodes are used to achieve focused directional emission, then beam directionality is improved, but package profile height increases
Solution Approach 1:
The patent separates the light generation function (top-emitting LED) from the light direction control function (reflector). This segmentation allows each component to be optimized independently, with the reflector providing the focused directional emission pattern while keeping the overall package profile compact
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 provides a cost-effective and high-output alternative to side-emitting diodes by redirecting radiation, achieving performance suitable for lighting and optical communications applications while being more compact and easier to mount than traditional side-emitting diodes.
Implementation Method 1
a surface mountable reflector affixed to the circuit substrate... The reflector can include at least one side wall and a reflective roof. Radiation emitted from the top and side surfaces of the diode are redirected toward an open end of the surface mountable reflector
Data Source
AI summary
A surface mountable reflector for use with a surface-emitting diode (e.g., LED) includes at least one side wall, a roof, and a mounting pad extending from at least one side wall to facilitate mounting of the surface mountable reflector to a circuit substrate, with the roof of the surface mountable reflector disposed over a diode mounted on the circuit substrate, whereby simulation of an edge-emitting diode is achieved.