OLED Display Light Blocking Layer for Contrast
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Solution Overview
Problem
Display devices face challenges in improving external light reflectance without compromising image quality, particularly in organic light-emitting diode (OLED) devices that do not use polarizing films, which can lead to reduced contrast and efficiency.
Innovation Solution
A display device structure is implemented with a via insulating layer, a first electrode, a pixel defining layer, a light emitting layer, an encapsulation layer with multiple stacked layers, and a light blocking layer to reduce external light reflection, while maintaining image quality and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a polarizing film is used to improve external light reflectance, then external light reflection is reduced, but the display device becomes thicker and loses light intensity
Solution Approach 1:
The invention transitions from using a polarizing film (a separate component layer) to forming light blocking portions directly within the encapsulation layers through sequential stacking. This integrates the light blocking function into the existing encapsulation structure, reducing overall device thickness while maintaining the light reflection reduction effect.
Solution Approach 2:
The invention combines the light blocking function with the encapsulation function by forming light blocking portions within the encapsulation layers. The first, second, and third encapsulation layers are sequentially stacked, with light blocking portions integrated into specific layers, merging two functions into one structure.
2Object-affected harmful factors
If a polarizing film is used to reduce external light reflection, then reflectance is improved, but light emission intensity from the display decreases
Solution Approach 1:
The invention applies light blocking properties locally at specific positions within the encapsulation structure rather than using a uniform polarizing film across the entire display. The light blocking portions are formed only in the first, second, and third encapsulation layers at strategic locations, allowing light to pass through other areas while blocking external light reflection at critical interfaces.
3Length of stationary object
If the encapsulation layers are made thinner to reduce device thickness, then device slimness is improved, but protection against external light and environmental factors is reduced
Solution Approach 1:
The invention uses a composite encapsulation structure with three sequentially stacked encapsulation layers, where at least one layer contains light blocking portions. This composite structure provides both environmental protection and light blocking functions while maintaining a thin overall profile, as the light blocking portions are integrated within the layers rather than adding separate thick components.
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 improves external light reflectance, enhancing the display's contrast and efficiency by strategically positioning and materializing the light blocking layers to minimize external light interference without the need for polarizing films.
Implementation Method 1
a first light blocking layer disposed on the third layer of the encapsulation layer to overlap the flat region of the pixel defining layer and form a second opening
Implementation Method 2
in the light emitting display device, since each of pixels of a display panel includes a light emitting element capable of emitting light by itself
Data Source
AI summary
A display device includes a via insulating layer on a substrate; a first electrode on the via insulating layer; a pixel defining layer including an inclined region on the first electrode and including a first opening exposing a portion of the first electrode, and a flat region at a side of the inclined region and in contact with the via insulating layer; a light emitting layer on the portion of the first electrode exposed by the first opening; organic particles on the flat region of the pixel defining layer; an encapsulation layer covering the pixel defining layer, the light emitting layer, and the organic particles, and including a first layer, a second layer, and a third layer; and a first light blocking layer on the third layer of the encapsulation layer to overlap the flat region of the pixel defining layer and form a second opening.