Display Device Refractive Index Gradient for Light Extraction
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Solution Overview
Problem
Display devices suffer from reduced light emitting efficiency and display quality due to light loss at interlayer interfaces within their multi-layered structures.
Innovation Solution
A display device structure is implemented with a substrate, transistor, light emitting element, encapsulation layer, sensing electrode, and multiple insulating layers, where the refractive index of the third insulating layer is higher than that of the second insulating layer, optimizing light transmission and reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If light passes through multiple layers in a display device, then light can be emitted to outside, but some light is lost by reflection at interlayer interfaces
Solution Approach 1:
An intermediate layer with refractive index between 1.30 and 1.45 is introduced between the encapsulation layer (refractive index 1.50-1.70) and the pixel electrode or organic light-emitting layer. This intermediate layer acts as a refractive index bridge, gradually transitioning the light from the high refractive index encapsulation layer to the lower refractive index layer, thereby reducing reflection at the interface and improving light extraction efficiency.
Solution Approach 2:
The patent changes the refractive index parameter of the intermediate layer to optimize light transmission. By selecting materials with specific refractive indices (1.30-1.45) that are lower than the encapsulation layer but higher than the underlying layer, the patent creates an optimal refractive index gradient that minimizes reflection losses at interfaces while maintaining the necessary multi-layered structure for device functionality.
2Reliability
If a multi-layered structure is used, then device functionality is achieved, but light emitting efficiency deteriorates
Solution Approach 1:
The intermediate layer with optimized refractive index (1.30-1.45) serves as a mediator that enables both device functionality and improved light emitting efficiency. It maintains the multi-layered structure necessary for device operation while simultaneously reducing interfacial reflection losses, thus resolving the contradiction between structural requirements and optical performance.
Solution Approach 2:
By adjusting the refractive index parameter of the intermediate layer to fall within 1.30-1.45, the patent optimizes the optical properties of the multi-layered structure without compromising its functional integrity. This parameter optimization allows light to pass through the necessary layers more efficiently while maintaining the structural complexity required for device functionality.
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 enhances light emitting efficiency and display quality by ensuring that some of the light emitted from the light emitting element is totally reflected and emitted forward, thereby improving frontal visibility.
Implementation Method 1
some of light emitted from the light emitting element may be totally reflected on an interface between the third portion of the second insulating layer and the third insulating layer to be emitted
Data Source
AI summary
The present disclosure relates to a display device, and a display device according to an embodiment includes a substrate, a transistor disposed on the substrate, a light emitting element connected to the transistor, an encapsulation layer disposed on the light emitting element, a sensing electrode disposed on the encapsulation layer, a first insulating layer disposed on the sensing electrode and including an opening, a second insulating layer disposed on the first insulating layer, and a third insulating layer disposed on the second insulating layer, wherein a refractive index of the third insulating layer is higher than that of the second insulating layer.