Switchable Viewing Angle LCD via Bias Voltage Control
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Solution Overview
Problem
Conventional liquid crystal displays (LCDs) with wide viewing angles lack privacy protection, as images can be easily viewed from different angles, and existing solutions like louver shielding films or dual light source backlight systems increase thickness and cost, or require additional components.
Innovation Solution
An LCD with switchable viewing angles is achieved by using a liquid crystal layer with negative liquid crystal molecules tilted at a pretilt angle, where applying a bias voltage to the first electrode controls the viewing angle, allowing switching between narrow and wide viewing modes without additional films or dual backlight systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a louver shielding film is used to cover the screen, then privacy protection is improved, but device complexity and ease of operation deteriorate due to additional components and fixed viewing angle
Solution Approach 1:
The patent applies the dynamics principle by making the viewing angle adjustable rather than fixed. The liquid crystal display can dynamically switch between narrow viewing angle mode (for privacy protection) and wide viewing angle mode (for normal display) through voltage control, eliminating the need for separate louver films and fixed-angle structures.
Solution Approach 2:
The patent applies the universality principle by making the liquid crystal display perform multiple functions: it can provide both privacy protection mode and normal wide viewing mode through a single device, without requiring additional louver shielding films or complex dual light source systems.
2Adaptability or versatility
If a dual light source backlight system is used, then viewing angle adjustability is improved, but thickness and weight increase remarkably
Solution Approach 1:
The patent applies the parameter changes principle by using voltage as the control parameter to adjust the liquid crystal molecule orientation, which in turn changes the viewing angle. This electrical parameter control avoids the need for mechanical or optical additions like dual light source systems, maintaining thin display structure.
Solution Approach 2:
The patent replaces the mechanical/optical approach of dual light source backlight systems with an electrical field-based liquid crystal molecule orientation control system. This substitution achieves viewing angle adjustability without adding physical thickness or weight.
3Adaptability or versatility
If a dual light source backlight system is used, then viewing angle adjustability is improved, but cost increases remarkably
Solution Approach 1:
The patent uses voltage parameter changes to control liquid crystal molecule orientation, achieving viewing angle adjustment through electrical control rather than expensive dual light source hardware. This reduces manufacturing complexity and cost while maintaining functionality.
Solution Approach 2:
The patent extracts and eliminates the need for expensive dual light source backlight components by using liquid crystal molecule orientation control. This simplification reduces material costs, manufacturing complexity, and assembly requirements while achieving the same viewing angle adjustability.
4Object-affected harmful factors
If liquid crystal molecules are tilted at pretilt angle, then narrow viewing angle is achieved, but light leakage in dark state occurs and contrast decreases
Solution Approach 1:
The patent applies dynamics by making the liquid crystal molecule orientation dynamic rather than static. Through voltage control, the molecules can switch between tilted (narrow viewing angle) and aligned (wide viewing angle) states, allowing the display to adapt between privacy mode and high-contrast mode as needed.
Solution Approach 2:
The patent uses voltage as a parameter to control the liquid crystal molecule tilt angle. By adjusting the voltage, the system can change the molecular orientation to balance between privacy protection and contrast performance, eliminating fixed trade-offs.
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 enables easy switching between narrow and wide viewing angles, improving privacy protection without increasing the LCD's thickness or cost, while maintaining good contrast and flexibility, comparable to conventional FFS type LCDs.
Implementation Method 1
When a bias voltage is applied to the first electrode, a vertical electric field is generated between the first substrate and the second substrate to cause the liquid crystal molecules in the liquid crystal layer to rotate
Implementation Method 2
When a bias voltage is applied to the first electrode, a vertical electric field is generated between the first substrate and the second substrate
Data Source
AI summary
An LCD with switchable viewing angle includes a first substrate, second substrate, and a liquid crystal layer. The first substrate is provided with a first electrode and a first alignment film thereon. The second substrate is provided with a second electrode, a third electrode and a second alignment film thereon. The liquid crystal layer is disposed between the first alignment film and the second alignment film, and includes a plurality of liquid crystal molecules. All of the liquid crystal molecules in the liquid crystal layer are tilted at the same pretilt angle relative to the alignment films. When no bias voltage is applied to the first electrode, the LCD shows a narrow viewing angle; and when a bias voltage is applied to the first electrode, the LCD shows a wide viewing angle.