Organic EL Display Light Emitting Elements Curved Surfaces
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Solution Overview
Problem
Organic EL displays suffer from unwanted rainbow-colored light interference due to the sterical shape of light emitting elements, which is caused by the presence of signal lines and driving transistors, leading to reduced image recognition and increased device thickness.
Innovation Solution
The display device incorporates light emitting elements with different thin film transistor structures and metal layers, each having distinct layer surfaces, arranged in a specific order to suppress reflected light interference while maintaining a thin form factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the protective layer or planarization layer covering the pixel driving circuit is made sufficiently thick to achieve a planarized surface, then the planarity of the light emitting portion is improved, but the thickness of the entire device increases
Solution Approach 1:
The patent applies asymmetric curvature to the layer surfaces of light emitting elements. Specifically, different light emitting elements (e.g., red, green, blue sub-pixels) are given different undulating surface profiles. This curvature variation causes reflected light from different elements to diverge in different directions, preventing constructive interference and eliminating rainbow-colored artifacts. The solution achieves planarity improvement without increasing overall device thickness by using controlled surface curvature rather than uniform thick planarization layers.
Solution Approach 2:
The patent employs asymmetric design by giving different layer surface profiles to different light emitting elements within the same pixel array. The undulating surfaces are intentionally made non-uniform and element-specific, creating asymmetric light reflection patterns. This asymmetry ensures that reflected light from adjacent pixels does not interfere constructively, thereby suppressing rainbow-colored interference while maintaining thin device structure.
2Object-affected harmful factors
If a thick planarization layer is used to achieve high accuracy planarized surface, then unwanted rainbow colored light interference is suppressed, but the device thickness increases and the thinness advantage of organic EL display is lost
Solution Approach 1:
Instead of using thick planarization layers, the patent introduces controlled undulating curvatures on the layer surfaces of light emitting elements. These curved surfaces cause reflected light to scatter in multiple directions rather than reflecting uniformly, which suppresses constructive interference and eliminates rainbow-colored artifacts. This approach achieves interference suppression while maintaining the inherent thinness of organic EL displays.
Solution Approach 2:
The patent changes the surface geometry parameter of light emitting elements from flat to undulating with specific curvature characteristics. By controlling the curvature radius and undulation amplitude of layer surfaces, the patent optimizes light reflection angles to prevent interference. This parameter modification effectively suppresses rainbow-colored light without requiring increased device thickness.
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 reduces the intensity of reflected light, enhancing image display performance without increasing the device thickness, thereby preserving the thinness advantage of organic EL displays.
Implementation Method 1
the reflected light LR other than specular light causes diffraction phenomenon
Implementation Method 2
light is multiply reflected from the organic layer Z14 between the anode electrode Z13 and the cathode electrode Z16
Data Source
AI summary
In one example embodiment, a display device for suppressing reflected light includes a driving circuit and a display region which includes a plurality of pixels. In one example embodiment, the plurality of pixels includes a first pixel having a first light emitting element which includes a first light emitting portion having a first layer surface. In one example embodiment, first pixel includes a second light emitting element which includes a second light emitting portion having a second, different layer surface. In one example embodiment, the first pixel includes a third light emitting element which includes a third light emitting portion having a third, different layer surface.