Input Sensing Layer Layout for OLED Light Extraction
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Solution Overview
Problem
Display devices, particularly organic light-emitting display devices, suffer from reduced light efficiency due to light emitted in lateral directions, and there are challenges in process reliability during manufacturing.
Innovation Solution
The display device incorporates a display panel with a first insulating layer having openings, a second insulating layer with corresponding openings, and a third insulating layer with a higher refractive index, along with conductive layers and interlayer insulating layers, to refract and reflect light, improving light output efficiency and reducing patterning inaccuracies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional organic light-emitting display device is used, then the device can emit light, but light is emitted in lateral directions causing decreased light efficiency
Solution Approach 1:
The patent converts the harmful lateral light emission into beneficial front-direction light by using high refractive index materials in the insulating layers. These materials refract and reflect lateral light rays, redirecting them toward the front emission direction, thereby transforming energy loss into useful light output.
Solution Approach 2:
The patent changes the refractive index parameter of the insulating layers by selecting materials with higher refractive indices (e.g., ITO with refractive index around 1.9-2.0). This parameter change alters the light propagation characteristics, causing total internal reflection and refraction that redirects lateral light toward the front direction.
2Loss of energy
If multiple insulating layers with different refractive indices are added to improve light efficiency, then light output is enhanced, but the device structure becomes more complex
Solution Approach 1:
The patent makes the insulating layers serve multiple functions: they provide electrical insulation between conductive layers and simultaneously act as optical elements for light redirection. By selecting materials like ITO that have both insulating properties and high refractive indices, the same layer performs both electrical and optical functions, reducing the need for additional dedicated optical components.
3Manufacturing precision
If conventional manufacturing processes are used, then the manufacturing process is simpler, but patterning inaccuracies occur reducing process reliability
Solution Approach 1:
The patent specifies precise refractive index parameters for the insulating layer materials (e.g., ITO with refractive index of 1.9-2.0) and controls layer thicknesses within specific ranges. These parameter controls ensure consistent optical performance and reliable patterning across manufacturing batches, improving both precision and reliability.
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 enhances light output efficiency by changing the path of light emission and improves manufacturing precision, resulting in higher display quality and reliability.
Implementation Method 1
a third insulating layer covering the display panel, the first insulating layer, and the second insulating layer, and having a second refractive index higher than the first refractive index
Implementation Method 2
Light generated in a light-emitting layer of the organic light-emitting display device may be emitted not only in a front direction but also in a lateral direction
Data Source
AI summary
Provided is a display device including a display panel having a plurality of pixel regions, and an input sensing layer on the display panel, wherein the input sensing layer includes: first sensing electrodes spaced from each other; second sensing electrodes spaced from each other, a first insulating layer on the display panel, having a first refractive index, and having a plurality of first openings defined in regions which overlap the plurality of pixel regions, a second insulating layer directly on the first insulating layer and having a plurality of second openings defined in regions which correspond to the plurality of first openings, and a third insulating layer covering the display panel, the first insulating layer, and the second insulating layer and having a second refractive index higher than the first refractive index, wherein the third insulating layer may overlap the plurality of pixel regions on a plane.