OLED Anode Bending Structure for Light Out-Coupling
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Solution Overview
Problem
Existing OLED display devices suffer from low external quantum efficiency due to energy loss within the device, primarily due to absorption by functional layers and waveguide modes, leading to issues like pixel light leakage and color mixing, which affect display quality.
Innovation Solution
A bending structure is formed in the anode layer of the OLED device corresponding to pixel regions, increasing internal reflection efficiency and light out-coupling efficiency, while preventing pixel light from leaking from side surfaces and reducing the risk of color mixing by reflecting light emitted from the side surfaces back onto the display screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional flat anode layer is used in OLED, then the device structure is simple and easy to manufacture, but the external quantum efficiency is limited due to energy loss from absorption by functional layers and waveguide modes
Solution Approach 1:
The anode layer is designed with a bending structure featuring an inclined surface instead of a flat configuration. This curved geometry modifies light propagation paths, enabling obliquely emitted light to reflect off the inclined surface and exit through the front surface, thereby increasing external quantum efficiency without significantly complicating the manufacturing process
Solution Approach 2:
The invention introduces a dimensional change by creating a three-dimensional bending structure in the anode layer with varying thickness. The inclined surface adds a new geometric dimension that redirects light paths from side emission to front emission, improving light out-coupling efficiency while maintaining structural feasibility
2Ease of manufacture
If light is emitted from side surfaces of pixel regions, then the device structure is simple, but pixel light leaks and causes color mixing which degrades display quality
Solution Approach 1:
The bending structure converts potentially harmful side-emitted light into beneficial front-emitted light. By designing the anode layer with an inclined surface, obliquely emitted light that would otherwise leak from side surfaces is reflected back toward the front, transforming a harmful effect into a useful contribution to display quality
Solution Approach 2:
The inclined surface of the bending structure acts as an intermediary element between the light emitting layer and the external environment. It intercepts obliquely emitted light and redirects it through reflection, serving as a mediating structure that prevents direct side leakage while maintaining optical efficiency
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 internal reflection and light out-coupling efficiencies, improves display quality by preventing color mixing, and maintains high contrast, thereby increasing the overall performance of OLED display devices.
Implementation Method 1
A bending structure is formed in a portion of an anode layer of the organic electroluminescent device corresponding to a pixel region. In this way, it can increase an internal reflection efficiency of the display device, increase a light out-coupling efficiency
Implementation Method 2
preventing pixel light from leaking from side surfaces, reduce a risk of color mixing, and improve display quality
Data Source
AI summary
An organic electroluminescent device, a method for manufacturing the same, and a display device. The organic electroluminescent device includes: a base substrate comprising a plurality of pixel regions thereon; a pixel electrode layer; a planarization layer, formed with a protrusion on a surface of the planarization layer facing away from the base substrate and at a position corresponding to at least one side edge of a periphery of each pixel region; an anode layer, the anode layer being electrically connected to the pixel electrode layer through a via hole, and the anode layer covering the pixel region and covering a side surface of the protrusion facing the pixel region; a light emitting layer, a height of a surface of the light emitting layer being less than a height of the anode layer covering the side surface of the protrusion; a pixel definition layer; and a cathode layer.