Dual Viewing-Angle LCD Panels With Polarization Rotation
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Solution Overview
Problem
Display devices, particularly those in vehicles, face challenges in controlling the viewing angle to ensure that the display image is not visible from the driver's seat while driving, while being visible from the passenger seat, with existing techniques using twisted nematic liquid crystal elements being insufficient in achieving the desired contrast ratio across different viewing angles.
Innovation Solution
A display device configuration that includes a display panel, a first viewing angle control panel with a twisted liquid crystal layer, a second viewing angle control panel with a twisted liquid crystal layer, and a polarization axis rotation element, where the alignment states of the liquid crystal layers differ, and the polarization axis rotation element rotates the polarization axis to control the viewing angle by modulating the polarization components, ensuring low transmittance on the driver's side and high transmittance on the passenger's side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single twisted nematic liquid crystal element is used for viewing angle control, then the device complexity is reduced, but the contrast ratio across different viewing angles is insufficient
Solution Approach 1:
The viewing angle control function is divided into multiple independent liquid crystal panels (first, second, third, and fourth panels) with different alignment states. Each panel controls light transmission in specific directions, and their combined effect achieves superior contrast ratio across all viewing angles compared to a single panel.
Solution Approach 2:
The system combines multiple liquid crystal panels with different molecular alignment configurations (different twist directions and angles) to create a composite optical system. This composite structure leverages the complementary strengths of each panel to achieve broad-spectrum viewing angle control with high contrast ratio.
2Measurement precision
If the alignment states of liquid crystal layers are made different to control viewing angles, then the viewing angle control precision is improved, but the device complexity increases
Solution Approach 1:
Each liquid crystal panel is configured with a specific local alignment state optimized for controlling light in particular directions. The first panel controls front viewing angles, the second controls side angles, the third controls rear angles, and the fourth controls opposite side angles, with each panel's alignment tailored to its specific functional requirement.
Solution Approach 2:
The solution extends viewing angle control from a single-dimensional approach (one panel) to a multi-dimensional approach by arranging four panels in different spatial orientations and alignment configurations, thereby achieving comprehensive three-dimensional viewing angle control.
3Manufacturing precision
If multiple viewing angle control panels are used to achieve high contrast ratio, then the viewing angle control precision is improved, but the loss of energy increases
Solution Approach 1:
The system dynamically controls the transmission state of each liquid crystal panel independently through separate electrode configurations. By selectively activating or deactivating specific panels based on the desired viewing direction, the system minimizes unnecessary light blocking and reduces energy loss while maintaining high contrast ratio when needed.
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
Effectively controls the viewing angle to prevent the display image from being seen by the driver while allowing it to be visible to the passenger, maintaining high transmittance and preventing image reflection on the windshield, thus enhancing visibility and safety.
Implementation Method 1
a first viewing angle control panel (1) comprising a first liquid crystal layer (LC1) including twisted liquid crystal molecules, a second viewing angle control panel (2) comprising a second liquid crystal layer (LC2) including twisted liquid crystal molecules
Implementation Method 2
a polarization axis rotation element (100) provided between the first viewing angle control panel (1) and the display panel (PNL)... The polarization axis rotation element (100) is configured to rotate the second polarization axis
Implementation Method 3
some techniques using a twisted nematic liquid crystal element have been suggested
Data Source
AI summary
According to one embodiment, a display device includes a display panel configured to modulate a first polarization component, a first viewing angle control panel including a first liquid crystal layer containing twisted liquid crystal molecules, a second viewing angle control panel including a second liquid crystal layer containing twisted liquid crystal molecules, and a polarization axis rotation element provided between the first viewing angle control panel and the display panel. A second polarization axis of a second polarization component which passed through the first viewing angle control panel is different from a first polarization axis of the first polarization component. The polarization axis rotation element is configured to rotate the second polarization axis.