Micro-LED Display Reflective Layer for Light Extraction and Color Control
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Solution Overview
Problem
Current display devices with small light emitting elements face challenges in achieving high luminous efficiency and display quality due to limitations in the design and structure of their light emitting elements and reflective layers.
Innovation Solution
A display device design featuring a substrate with thin film transistors, electrodes, and light emitting elements of specific semiconductor layers, where the reflective layer has inclined surfaces and light scattering particles in the insulating layer to enhance light emission efficiency and reduce color deviation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the light emitting element size is reduced to nanometer or micrometer scale, then the display device can achieve higher resolution, but the luminous efficiency and light extraction become insufficient
Solution Approach 1:
The patent introduces a reflective layer with specific local optical properties beneath the light emitting element. This reflective layer has high reflectivity in specific directions and wavelength ranges, creating localized optical enhancement that compensates for the reduced light output from miniaturized elements without affecting the overall device resolution
Solution Approach 2:
The reflective layer is constructed as a composite structure combining multiple materials with different optical characteristics. This composite design enables the layer to reflect light efficiently in specific directions while maintaining compatibility with the nanometer-scale light emitting element structure, thereby improving luminous efficiency without sacrificing resolution
2Device complexity
If a conventional flat reflective layer is used, then the structure is simple, but the light extraction efficiency and viewing angle characteristics are poor
Solution Approach 1:
The reflective layer is designed with a curved or dome-shaped profile rather than a flat surface. This curvature enables broader light extraction angles and improved viewing characteristics by directing light toward the viewer from multiple angles, while the overall structural complexity remains manageable through standardized manufacturing processes
Solution Approach 2:
The reflective layer extends in the vertical dimension with a controlled profile height, creating a three-dimensional optical structure. This vertical dimensionality allows the layer to manipulate light extraction patterns and viewing angles effectively, achieving superior illumination characteristics without requiring complex lateral structural variations
3Ease of manufacture
If the reflective layer has a large area covering multiple pixels, then the manufacturing is simplified, but the color accuracy and pixel independence are compromised
Solution Approach 1:
The reflective layer is segmented into discrete regions corresponding to individual pixels or pixel groups. Each segment can be independently optimized for its specific pixel's color characteristics, allowing precise color control per pixel while maintaining manufacturing efficiency through batch processing of similar segments
Solution Approach 2:
Different regions of the reflective layer are designed with locally optimized properties including varying reflectivity, curvature, and material composition tailored to each pixel's specific color requirements. This local customization enables precise color accuracy for each pixel while the overall segmented structure allows efficient manufacturing through modular fabrication approaches
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 improves luminous efficiency and display quality by optimizing light emission and reducing color deviation through the use of inclined reflective surfaces and light scattering elements, resulting in enhanced performance of the display device.
Implementation Method 1
a reflective layer on the insulating layer
Implementation Method 2
light scattering particles in the insulating layer
Data Source
AI summary
A display device is capable of improving luminous efficiency and display quality and includes: a substrate; a thin film transistor on the substrate; a first electrode on the substrate and connected to the thin film transistor; a second electrode on the substrate and spaced apart from the first electrode; a plurality of light emitting elements between the first and second electrodes and electrically connected to each of the first and second electrodes; an insulating layer on the plurality of light emitting elements; and a reflective layer on the insulating layer. Each of the plurality of light emitting elements includes: a first semiconductor layer, an active layer on the first semiconductor layer, and a second semiconductor layer on the active layer.