Display Device Refractive Index Layers Prevent Color Mixing
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Solution Overview
Problem
Display devices experience color-mixing issues due to light emission from adjacent wavelength conversion parts, leading to compromised image quality, as light from one pixel region can cause unintended light emission from nearby regions.
Innovation Solution
A display device structure is implemented with a first substrate having defined pixel regions and a second substrate with display elements, where a low refractive index layer is placed between the substrates, and specific wavelength conversion layers and color filter layers are used to manage light emission and prevent color-mixing by controlling the total reflection critical angle and incident angles of light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional display structure without refractive index control layers is used, then the device complexity is low, but color-mixing occurs between adjacent pixels reducing image quality
Solution Approach 1:
A first layer with higher refractive index and a second layer with lower refractive index are introduced as intermediary layers between the wavelength conversion layers and the common light guide. These layers act as optical mediators that control light propagation through total internal reflection, preventing light from leaking into adjacent pixel regions and causing color-mixing, while maintaining the overall display structure.
Solution Approach 2:
The refractive indices of the layers are specifically designed with distinct values (first refractive index higher than second refractive index) to create the necessary optical contrast for total internal reflection. This parameter change enables precise control over light propagation paths, ensuring light remains confined to its designated pixel region while passing through the common light guide.
2Productivity
If light is allowed to pass through all wavelength conversion layers to the common light guide, then light utilization is high, but color-mixing increases due to light emission from adjacent regions
Solution Approach 1:
The first and second layers are positioned specifically between the wavelength conversion layers of adjacent pixels, creating localized optical control zones. Each layer pair is configured to control light propagation in its specific region, allowing light to pass through the common light guide while preventing horizontal light leakage into adjacent pixel areas through total internal reflection at the interface between layers of different refractive indices.
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 effectively reduces color-mixing between adjacent pixels, enhancing the image quality by ensuring that light is emitted only from the intended pixel region, thereby improving the display's color purity and viewing angle properties.
Implementation Method 1
A total reflection critical angle at an interface between the first layer and the second layer is smaller than an incident angle of light which is emitted from the first display element and is towards the second wavelength conversion layer
Data Source
Figure 1~2
Figure 3
Figure 4A~4B
AI summary
The present disclosure provides a display device including a first substrate in which a first pixel region and a second pixel region are defined, a second substrate including a first display element and a second display element, a first layer having a first refractive index, and a second layer having a second refractive index. The first substrate includes a first wavelength conversion layer disposed in the first pixel region and a second wavelength conversion layer disposed in the second pixel region. A total reflection critical angle between the first layer and the second layer is smaller than an incident angle of light which is emitted from the first display element and is incident into the second wavelength conversion layer.