Distributed Bragg Reflector Micro-LED Display Structure
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Solution Overview
Problem
Micro-LED displays face challenges in manufacturing complexity and cost-effectiveness while striving to enhance brightness and color performance, with existing technologies not adequately addressing these issues.
Innovation Solution
A display device design incorporating a backplane with light-emitting devices sandwiched between two distributed Bragg reflector structures, where the reflector structures have larger projected areas than the devices, allowing for improved light reflection and color purity, and are manufactured as whole layers for ease and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If distributed Bragg reflector structures are added to enhance color purity and light reflection, then color purity and brightness are improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The distributed Bragg reflector is segmented into multiple alternating layers of materials with different refractive indices (e.g., SiO2 and TiO2). Each layer is thin and has a specific optical thickness of λ/4n, where λ is the target wavelength and n is the refractive index. This segmentation allows the reflector to selectively reflect specific wavelengths while transmitting others, thereby enhancing color purity and brightness without requiring a single complex component.
Solution Approach 2:
The optical properties of the Bragg reflector are controlled by changing parameters such as layer thickness, refractive index, and number of periods. By adjusting these parameters, the reflector can be optimized for specific color wavelengths. For example, varying the thickness of alternating layers allows tuning of the reflected wavelength, enabling precise control over color purity and brightness while managing structural complexity.
2Manufacturing precision
If distributed Bragg reflector structures are added to enhance color purity and light reflection, then color purity is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The Bragg reflector is divided into multiple alternating layers of materials with different refractive indices. Each layer has a precise optical thickness of λ/4n, which is critical for achieving high color purity. This segmentation enables selective reflection of specific wavelengths while transmitting others, thereby enhancing color purity. The repetitive structure allows standardization in manufacturing, reducing complexity despite the multiple layers.
Solution Approach 2:
Color purity is controlled by changing parameters such as layer thickness, refractive index, and number of periods. By adjusting these parameters, the reflector can be optimized for specific color wavelengths. For example, varying the thickness of alternating layers allows tuning of the reflected wavelength, enabling precise control over color purity while managing structural complexity through parameter optimization.
3Loss of energy
If larger projected area Bragg reflector structures are used to improve light reflection, then light reflection efficiency is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The Bragg reflector structure is merged with the substrate or integrated into the existing device architecture. By combining the reflector function with the substrate, the overall device structure is simplified, and manufacturing processes are reduced. This integration maintains high light reflection efficiency while improving ease of manufacture and reducing costs.
Solution Approach 2:
The Bragg reflector is designed to serve multiple functions: enhancing light reflection efficiency, improving color purity, and potentially serving as a structural component of the device. This multi-functionality reduces the need for separate components, simplifying manufacturing and reducing costs while maintaining high reflection efficiency.
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 design achieves higher color purity and reduced manufacturing complexity, enhancing the display's image quality and cost-effectiveness by reflecting light between the Bragg reflector layers, thereby narrowing the light spectrum and increasing straight light intensity.
Implementation Method 1
a first distributed Bragg reflector structure disposed between the backplane and the light-emitting devices, and a second distributed Bragg reflector structure disposed between the light-emitting devices and the front surface
Implementation Method 2
The light emitted by the light-emitting devices is reflected between the first distributed Bragg reflector layer and the second distributed Bragg reflector layer, and the full width at half maximum of the spectrum of the light is reduced
Data Source
AI summary
A display device including a backplane, a plurality of light-emitting devices, a first distributed Bragg reflector layer and a second distributed Bragg reflector layer is provided. The light-emitting devices are disposed on the backplane. The first distributed Bragg reflector layer is disposed between the backplane and the light-emitting devices. The light-emitting devices are disposed between the first distributed Bragg reflector layer and the second distributed Bragg reflector layer. A projected area of the first distributed Bragg reflector layer on the backplane is larger than a projected area of one of the light-emitting devices on the backplane or a projected area of the second distributed Bragg reflector layer on the backplane is larger than a projected area of one light-emitting device on the backplane.