Micro LED Light Pipe for Fill Factor and Color Tuning
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Solution Overview
Problem
Current micro LED devices face challenges in achieving high fill factor and tunable color emission spectrum, particularly in integrating micro LED devices on a substrate with increased efficiency and precise color control for lighting and display applications.
Innovation Solution
The integration of micro LED devices on a substrate involves a light pipe structure around each device, accompanied by a wavelength conversion layer comprising phosphor particles, which allows for refraction, internal reflection, and lateral spreading of light, enabling increased fill factor and tunable color emission spectra through careful configuration of light pipes and wavelength conversion layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If micro LED devices are integrated on a substrate without light pipes, then the device structure is simpler, but the fill factor is reduced and color emission control is less precise
Solution Approach 1:
A light pipe structure is introduced as an intermediary component between the micro LED device and the substrate. The light pipe has a lateral dimension greater than the micro LED device, allowing it to collect and guide light over a larger area, thereby increasing the fill factor without complicating the overall device integration process
Solution Approach 2:
The light pipe extends in the lateral dimension beyond the micro LED device footprint. By increasing the lateral dimension of the light pipe relative to the micro LED device, the effective light emission area is expanded, achieving higher fill factor while maintaining device simplicity
2Ease of manufacture
If micro LED devices are integrated on a substrate without wavelength conversion layers, then the device structure is simpler, but the color emission spectrum is not tunable
Solution Approach 1:
Wavelength conversion layers with different phosphor compositions and particle size distributions are applied to the light pipe. By changing the phosphor parameters (composition, size, distribution), the color emission spectrum can be tuned across different regions of the device, achieving versatility while maintaining a relatively simple device structure
Solution Approach 2:
Different wavelength conversion layers with specific phosphor properties are applied to different regions of the light pipe. This allows each region to emit different colors by controlling the phosphor composition and particle size distribution locally, enabling spectrum tunability without requiring complex device structures
3Productivity
If light pipes with large lateral dimensions are used, then the fill factor is increased, but the device complexity increases
Solution Approach 1:
The light pipe structure serves multiple functions simultaneously: it increases the fill factor by extending laterally, guides and refraction light toward the wavelength conversion layer, and provides a platform for applying different wavelength conversion layers. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity
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 fill factor and color gamut of micro LED devices, allowing for efficient light emission with improved color accuracy and reduced power consumption, while preventing secondary absorption and unintended color shifts.
Implementation Method 1
The light pipe in accordance with embodiments of the invention is designed to allow refraction of incident light form the micro LED device out of the light pipe toward the wavelength conversion layer
Implementation Method 2
The light pipe in accordance with embodiments of the invention is designed to allow refraction of incident light form the micro LED device out of the light pipe toward the wavelength conversion layer, as well as to cause internal reflection and lateral spreading of incident light from the micro LED device within the light pipe
Implementation Method 3
A light pipe is formed around the micro LED device, and a wavelength conversion layer comprising phosphor particles is formed over the light pipe
Data Source
AI summary
A light emitting device and method of manufacture are described. In an embodiment, the light emitting device includes a micro LED device, a light pipe around the micro LED device to cause internal reflection of incident light from the micro LED device within the light pipe, and a wavelength conversion layer comprising phosphor particles over the light pipe. Exemplary phosphor particles include quantum dots that exhibit luminescence due to their size, or particles that exhibit luminescence due to their composition.