Display Device Light Control Layer Refractive Index Optimization
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Solution Overview
Problem
Conventional display devices face challenges in enhancing light efficiency and luminance, particularly at side surfaces, due to limitations in optical functional layers and refractive index differences, which affect viewing angles and light output.
Innovation Solution
A display device design incorporating a high refractive index pattern and a low refractive index layer, with specific refractive index differences and separation distances, is implemented to optimize light control and increase luminance at side surfaces, including a light control layer with a high refractive index pattern covering emissive regions and a low refractive index layer covering both emissive and non-emissive regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional display device structure is used, then the manufacturing process is simple, but the light efficiency and luminance at side surfaces are insufficient
Solution Approach 1:
The patent applies local quality by creating a high refractive index pattern only in specific regions (emissive regions) rather than uniformly across the entire display. This localized application of high refractive index material optimizes light extraction at side surfaces where it is most needed, while maintaining simpler structures in non-emissive areas, thus improving luminance at side surfaces without proportionally increasing overall device complexity
Solution Approach 2:
The patent uses composite materials by combining regions with different refractive indices (high refractive index pattern material and low refractive index layer) within the same display structure. This composite approach allows optimization of light extraction efficiency through refractive index contrast, enabling improved side surface luminance while managing the complexity through strategic material placement
2Illumination intensity
If the refractive index difference is increased to improve light efficiency, then the light output at side surfaces improves, but the viewing angle control becomes more difficult
Solution Approach 1:
The patent applies parameter changes by precisely controlling the refractive index values of different layers (high refractive index pattern with refractive index of 1.7-1.9 and low refractive index layer with refractive index of 1.3-1.5) and their thicknesses. This systematic adjustment of optical parameters enables optimization of both light efficiency and viewing angle characteristics through controlled refractive index contrast rather than uncontrolled increases
3Illumination intensity
If the separation distance between high refractive index pattern and emissive region is increased to optimize light control, then the light efficiency improves, but the device area increases
Solution Approach 1:
The patent applies partial action by implementing the high refractive index pattern only in emissive regions rather than across the entire display area. The separation distance of 1-5 μm is optimized to provide sufficient light control while minimizing the additional area consumed, applying the light management structure only where it is needed for light emission rather than uniformly across the whole device
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 effectively enhances light efficiency and luminance at side surfaces by managing refractive index differences and separation distances, improving light output and viewing angles, particularly at 45 degrees, thereby increasing the overall light emission efficiency.
Implementation Method 1
The light control layer includes: a high refractive index pattern, which is disposed on the sensing insulation layer and covers each of the plurality of emissive regions in a plan view and has a first refractive index; and a low refractive index layer, which covers the high refractive index pattern and the conductive layer, overlaps the non-emissive region and the emissive region, and has a second refractive index smaller than the first refractive index
Data Source
AI summary
A display device includes: a display panel; an input sensing unit including a sensing insulation layer and a conductive layer, which overlaps the non-emissive region; a light control layer disposed on the input sensing unit; and a window disposed on the light control layer. The light control layer includes: a high refractive index pattern, which covers each of a plurality of emissive regions in a plan view and has a first refractive index; and a low refractive index layer, which covers the high refractive index pattern and the conductive layer, and has a second refractive index smaller than the first refractive index. A separation distance by which one side surface of the high refractive index pattern is spaced apart from one side surface of an emissive region closest to the one side surface of the high refractive index pattern among the emissive regions ranges from 6 μm to 9 μm.