Spiral Contact LED Induces Electromagnetic Field for Collimated Light
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Solution Overview
Problem
Prior micro-LEDs suffer from sub-optimal radiation patterns due to cavity effects, leading to divergent light emission rather than collimation, which affects extraction efficiency and directionality.
Innovation Solution
A light emitting diode structure with a spiral-shaped contact that induces an electromagnetic field, shaping the emitted light to be collimated by interacting with the light as it passes through the semiconductor body, potentially using a mesa-shaped structure with reflective walls to enhance collimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform p-contact is used at the top of the μLED structure, then the manufacturing is simple, but the radiation pattern is sub-optimal causing light to diverge rather than collimate
Solution Approach 1:
The patent applies asymmetry by replacing the uniform p-contact with an asymmetric contact structure that has different geometries in different regions. This asymmetric contact distribution creates non-uniform current density and electromagnetic field patterns that actively shape the emitted light into a collimated beam, resolving the contradiction between manufacturing simplicity and beam directionality.
Solution Approach 2:
The patent implements local quality by varying the contact properties (geometry, material, or doping) in different regions of the contact structure. This allows different parts of the contact to serve different functions: some regions promote light extraction while others shape the beam, enabling both ease of manufacture and optimal radiation pattern through spatially differentiated contact characteristics.
2Productivity
If the cavity effect guides light straight towards the bottom of the LED, then the light extraction path is direct, but the emitted light diverges instead of being collimated
Solution Approach 1:
The patent introduces an intermediary electromagnetic field generated by the asymmetric contact structure that acts as a mediator between the light emission process and the final light output. This electromagnetic field interacts with the emitted photons to shape and collimate the beam while maintaining efficient extraction, effectively mediating between direct extraction and beam shaping requirements.
Solution Approach 2:
The patent changes key parameters including the electromagnetic field distribution, current density profile, and contact geometry to transform the light emission characteristics. By adjusting these parameters through the asymmetric contact design, the system achieves both high extraction efficiency and collimated output, resolving the contradiction between direct extraction and beam collimation.
3Shape
If a spiral-shaped contact is used to induce electromagnetic field, then the light collimation is improved, but the device complexity increases
Solution Approach 1:
The patent applies self-service by designing the asymmetric contact structure to automatically generate the required electromagnetic field patterns and light shaping effects through its own geometry and electrical properties. The contact structure serves dual purposes: as an electrical contact and as an active beam-shaping element, eliminating the need for separate complex optical components and reducing overall device complexity despite the asymmetric design.
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 induced electromagnetic field directs light towards reflective surfaces, resulting in more collimated output with reduced beam divergence, enhancing brightness and reducing light spread into adjacent devices or detectors.
Implementation Method 1
The first contact is connected to the top surface of the body and has a spiral shape to induce an electromagnetic field
Implementation Method 2
LEDs convert electrical energy into optical energy. In semiconductor LEDs, light is usually generated through recombination of electrons, originating from an n-type doped semiconductor layer, and holes originating from a p-type doped semiconductor layer
Implementation Method 3
The inner walls of the μLED reflect light, and if the LED has a semi-parabolic shape, the walls will direct the reflected light out the bottom of the LED
Data Source
AI summary
Embodiments relate to a light emitting structure including a light emitting diode, a first contact, and a second contact. The light emitting diode includes a body of transparent semiconductor material with a top surface and a light emitting region below the top surface. The light emitting region emits light in response to current passing through the light emitting region; the emitted light passes through the body of the light emitting diode. The first contact is connected to the top surface of the body and has a spiral shape to induce an electromagnetic field. The electromagnetic field shapes the light emitted from the light emitting region and passes through the body of the light emitting diode. The second contact is connected to a surface of the light emitting structure. A voltage difference can be applied across the first contact and second contact to generate the current through the light emitting region.