Switchable Viewing Angle LCD via Third Electrode Bias Voltage
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Solution Overview
Problem
Conventional LCDs with wide viewing angles fail to protect user privacy in public settings, 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 are inconvenient.
Innovation Solution
An LCD with a switchable viewing angle is achieved by applying different bias voltages to a third electrode, allowing the liquid crystal molecules to rotate and control the viewing angle between wide and narrow settings without the need for additional films or dual light sources, using a first substrate, a second substrate, and a liquid crystal layer with positive liquid crystal molecules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a louver shielding film is used to cover the screen, then the viewing angle is reduced to protect privacy, but the device complexity and cost increase due to additional components
Solution Approach 1:
The patent merges the privacy protection function with the existing liquid crystal display structure by adding a third electrode to the substrate, eliminating the need for separate louver shielding films. The liquid crystal molecules themselves perform both display and privacy protection functions through voltage-controlled orientation changes.
Solution Approach 2:
The liquid crystal molecules serve themselves by automatically adjusting their orientation based on applied voltage to provide both wide viewing angle for display and narrow viewing angle for privacy protection, without requiring external mechanical shutters or additional optical films.
2Adaptability or versatility
If a dual light source backlight system is used to adjust viewing angle, then the viewing angle can be switched between wide and narrow, but the thickness and cost of the LCD increase remarkably
Solution Approach 1:
The patent changes the electrical parameter (bias voltage) applied to the liquid crystal layer to switch between wide and narrow viewing angles. By varying the voltage magnitude, the liquid crystal molecules reorient themselves, dynamically adjusting the viewing angle without adding physical layers or components that would increase thickness.
Solution Approach 2:
The patent replaces the mechanical dual light source backlight system with an electrical control mechanism. Instead of physically switching between different optical paths using mechanical components, the system uses electrical voltage to control liquid crystal molecule orientation, achieving viewing angle adjustment without mechanical movement or additional optical layers.
3Adaptability or versatility
If a dual light source backlight system is used to adjust viewing angle, then the viewing angle can be switched between wide and narrow, but the cost of the LCD increases
Solution Approach 1:
The patent combines multiple functions (display, wide viewing angle, narrow viewing angle for privacy) into a single integrated liquid crystal display structure with a third electrode, eliminating the need for separate dual backlight systems and reducing manufacturing complexity and cost.
Solution Approach 2:
The liquid crystal layer with the third electrode performs multiple functions: it provides the display function, enables wide viewing angle when low voltage is applied, and enables narrow viewing angle for privacy protection when high voltage is applied. This multi-functionality eliminates the need for separate dedicated components for each function, reducing overall system cost.
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 LCD can easily switch between wide and narrow viewing angles by adjusting bias voltages, maintaining flexibility and reducing thickness and cost, while effectively protecting privacy by reducing light leakage and contrast when viewed from different angles.
Implementation Method 1
Liquid crystal molecules in the liquid crystal layer are positive liquid crystal molecules. When a second bias voltage having a relatively large magnitude is applied to the third electrode, a vertical electric field along the vertical direction is generated between the substrates, the positive liquid crystal molecules will rotate in a plane orthogonal to the substrates
Implementation Method 2
When a second bias voltage having a relatively large magnitude is applied to the third electrode, a vertical electric field along the vertical direction is generated between the substrates, the positive liquid crystal molecules will rotate in a plane orthogonal to the substrates to possess a relatively large tilt angle relative to the substrates
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 second electrode. In an embodiment, the first electrode is a pixel electrode, and the second electrode is a common electrode. The second substrate is provided with a third electrode. Liquid crystal molecules in the liquid crystal layer are positive liquid crystal molecules. When a first bias voltage is applied to the third electrode, the LCD is displayed with a wide viewing angle; and when a second bias voltage greater than the first bias voltage is applied to the third electrode, the LCD is displayed with a narrow viewing angle.