LED Collimation Walls for AR/VR Displays
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Solution Overview
Problem
LEDs emit light in a Lambertian-like distribution with significant divergence, making them unsuitable for imaging applications in electronic display devices such as virtual reality and augmented reality systems, where improved collimation is needed to enhance image quality.
Innovation Solution
The use of walls surrounding LEDs, coated with a metal layer and potentially incorporating color converting materials like semiconductor quantum dots, to collimate light by absorption and reflection, combined with an array of optical lenses to further reduce divergence, ensuring the light is focused along the focal axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LEDs are used as light sources in electronic display devices, then energy efficiency and longevity are improved, but light divergence becomes too significant for imaging applications
Solution Approach 1:
The patent introduces an intermediary collimating structure between the LED light source and the imaging system. This structure includes a first portion within the semiconductor layer and a second portion extending beyond the surface, acting as a mediator to reshape the light distribution from Lambertian to a more collimated pattern suitable for imaging applications.
Solution Approach 2:
The collimating structure utilizes the vertical dimension by extending from within the semiconductor layer to above the surface, creating a three-dimensional light manipulation approach. This dimensional transition allows the structure to intercept and redirect light rays traveling at various angles, converting divergent light into a more parallel beam.
2Shape
If walls are added to collimate light by absorption and reflection, then light divergence is reduced, but device complexity increases
Solution Approach 1:
The patent merges multiple functions into the collimating walls: light collimation through geometric structure, electrical power delivery through metal layer coating, and color conversion through quantum dot integration. This consolidation reduces the need for separate components and simplifies the overall device architecture despite the advanced functionality.
Solution Approach 2:
The collimating walls are designed as multi-functional elements that simultaneously perform light collimation, electrical power delivery to the LED, and color conversion. This universal design approach allows a single structure to fulfill multiple roles, reducing device complexity by eliminating the need for separate components for each function.
3Shape
If optical lenses are added to further collimate light, then divergence angle is reduced, but manufacturing complexity increases
Solution Approach 1:
The collimating system is segmented into multiple functional portions: the first portion within the semiconductor layer for initial light interaction, the second portion extending beyond the surface for further collimation, and the metal layer coating for electrical connection. This segmentation allows each portion to be optimized independently while simplifying the overall manufacturing process.
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 solution effectively reduces the divergence angle of light emitted by LEDs, improving image quality and enabling more precise light control in display devices, particularly in near-eye displays for augmented and virtual reality systems.
Implementation Method 1
The wall absorbs and/or reflects at least part of the light beam to reduce in the divergence of the light beam
Implementation Method 2
The wall absorbs and/or reflects at least part of the light beam to reduce in the divergence of the light beam
Implementation Method 3
Each optical lens faces a LED and focuses the light emitted by the LED in a direction along the focal axis of the optical lens to further reduce the divergence angle of the light
Data Source
AI summary
A display device includes a plurality of light emitting diodes (LEDs) having walls that extend through a transparent semiconductor layer and beyond the surface of the transparent semiconductor layer. Each of the walls surrounds at least part of each of the plurality of LEDs to collimate the light emitted by the plurality of LEDs. In some embodiments, the walls collimate the light emitted by the LEDs by reflecting the light or absorbing a portion of the light. The display device may further include an array of optical lenses that faces the surface of the transparent semiconductor layer to further collimate the light emitted from the LEDs.