Dynamic Viewing Angle Control via Liquid Crystal Layer
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Solution Overview
Problem
Existing OLED display devices lack user control over viewing angles, making it difficult to limit unauthorized observation, and existing solutions with polarizing plates or electrically controllable liquid crystal layers are either fixed or inefficient.
Innovation Solution
A display device with a liquid crystal layer between the organic light emitting elements and a substrate, driven by sub-electrodes made of indium tin oxide, indium zinc oxide, or magnesium-silver alloy, allowing for selective control of viewing angles by applying voltage to generate an electric field that aligns or randomizes liquid crystal molecules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a polarizing plate or polarizing film is provided on the upper substrate to limit the viewing angle, then the viewing angle is limited, but the user cannot control the viewing angle and it is fixed
Solution Approach 1:
The patent applies a liquid crystal layer that can dynamically change its molecular alignment based on applied voltage. When voltage is applied, the liquid crystal molecules align in a specific direction to limit the viewing angle; when voltage is removed, the molecules return to a random state allowing wide viewing angles. This dynamic switching capability enables user-controlled adaptability of the viewing angle.
Solution Approach 2:
The patent changes the physical state of the liquid crystal layer by applying or removing voltage. The liquid crystal molecules transition between aligned and random states based on the electrical parameter (voltage), thereby controlling the viewing angle. This parameter-based control allows flexible adjustment of viewing angle without physical modification of the display structure.
2Adaptability or versatility
If liquid crystal is placed between the substrate and transparent substrate to enable viewing angle control, then viewing angle can be controlled, but the device thickness increases
Solution Approach 1:
The patent uses a thin liquid crystal layer as a flexible optical control element. The liquid crystal layer is deposited as a thin film between the upper substrate and the transparent substrate, providing viewing angle control functionality while minimizing thickness increase. The thin film structure allows the device to maintain a relatively compact profile while achieving the desired optical control capability.
3Illumination intensity
If sub-electrodes are made of transparent or semi-transparent materials like ITO, IZO, or MgAg alloy, then light transmission is maintained, but manufacturing complexity increases
Solution Approach 1:
The patent changes the material parameter of the sub-electrodes from traditional opaque conductive materials to transparent or semi-transparent materials such as ITO (indium tin oxide), IZO (indium zinc oxide), or MgAg (magnesium-silver) alloy. This material parameter change enables light transmission through the electrode structure while maintaining electrical functionality, resolving the contradiction between light transmission and manufacturing ease.
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
Enables user-controlled selective limitation of viewing angles, maintaining high performance and reducing device thickness by allowing light emission at either wide or narrow angles depending on the electric field applied, thus enhancing privacy and efficiency.
Implementation Method 1
a liquid crystal layer between a second pixel electrode and a second substrate... when a voltage difference is applied between the sub-electrode and the second pixel electrode an electric field is generated in the liquid crystal layer. This electric field preferably causes the liquid crystal molecules in the liquid crystal layer to become randomly aligned... if no electric field is applied between the sub-electrode and the second pixel electrode, the liquid crystal molecules between a sub-electrode and an opposite second pixel electrode are substantially aligned with each other
Data Source
AI summary
A display device having first and second substrates arranged opposite to each other, a semiconductor device on the first substrate, an organic light emitting element on the first substrate and an optical unit between the organic light emitting element and the second substrate. The display device configured to adjust angle viewing modes, e.g., a narrow angle viewing mode and a wide angle viewing mode, by selectively applying a voltage to the organic light emitting element and the optical unit.