Micro-LED Display Optics for Higher Light Efficiency and Color Purity
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Solution Overview
Problem
Existing display devices face challenges in improving luminous efficiency and preventing color mixture of lights, particularly in micro-LED display panels used in head-mounted displays.
Innovation Solution
The display device incorporates a substrate with partition walls, a wavelength conversion layer, scatterers, a light-blocking member, and optical patterns with specific refractive indices and shapes to enhance light focusing and reduce color mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a wavelength conversion layer is used to convert light wavelengths for different colors, then color representation is improved, but luminous efficiency deteriorates due to energy loss in conversion
Solution Approach 1:
The patent extracts the wavelength conversion function from a single layer and distributes it across multiple specialized layers (blue conversion layer, green conversion layer, red conversion layer), each containing scatterers with specific refractive indices optimized for their respective wavelength ranges. This separation reduces energy loss by matching scatterer properties to specific wavelengths rather than using a general-purpose conversion layer.
Solution Approach 2:
Different regions of the display device have locally optimized properties: the blue conversion layer has scatterers with refractive index 1.3-1.5, the green conversion layer has scatterers with refractive index 1.6-1.8, and the red conversion layer has scatterers with refractive index 1.9-2.1. This local optimization of scatterer refractive indices to match specific wavelength requirements improves conversion efficiency while maintaining color accuracy.
2Illumination intensity
If light-blocking members are added to prevent color mixing between adjacent emission areas, then color purity is improved, but device complexity increases
Solution Approach 1:
The patent merges the light-blocking function with the partition wall structure. The partition walls are configured to extend between adjacent emission areas and include light-blocking members integrated within them, eliminating the need for separate light-blocking structures. This integration maintains color purity while reducing overall device complexity.
Solution Approach 2:
The partition walls serve multiple functions simultaneously: they provide structural separation between emission areas, contain light-blocking members to prevent color mixing, and support the wavelength conversion layers. This multi-functionality reduces the number of separate components needed while achieving both color purity and structural integrity.
3Loss of energy
If optical patterns with high refractive index are used to focus light, then luminous efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes the refractive index parameters of scatterers within specific ranges (blue: 1.3-1.5, green: 1.6-1.8, red: 1.9-2.1) rather than requiring exact values. This parameter optimization within ranges allows for manufacturing tolerance while maintaining effective light focusing and conversion efficiency.
Solution Approach 2:
The optical patterns utilize scattered light paths through curved interfaces created by the scatterer distribution rather than requiring precise geometric lens shapes. This approach to light focusing is more tolerant of manufacturing variations while still achieving improved luminous efficiency through controlled light scattering and redirection.
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 improves light efficiency and suppresses color mixing, resulting in enhanced display performance.
Implementation Method 1
a wavelength conversion layer over the light-emitting element in the emission area, and including a base resin, and a scatterer dispersed in the base resin and that converts a wavelength of light emitted from the light-emitting element
Implementation Method 2
at least one optical pattern on the wavelength conversion layer in the emission area, and having an upwardly protruding shape... A refractive index of the optical pattern may be greater than a refractive index of the color filter
Data Source
AI summary
A display device includes a substrate, a partition wall on the substrate, a light-emitting element in an emission area partitioned by the partition wall on the substrate, and extending in a thickness direction of the substrate, a wavelength conversion layer over the light-emitting element in the emission area, and including a base resin, and a scatterer dispersed in the base resin and that converts a wavelength of light emitted from the light-emitting element, a light-blocking member on the partition wall, and at least one optical pattern on the wavelength conversion layer in the emission area, and having an upwardly protruding shape.