Switchable Viewing Angle LCD With Dual Pretilt Angles
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Solution Overview
Problem
Conventional liquid crystal displays (LCDs) lack a mechanism to dynamically switch between wide and narrow viewing angles without increasing thickness or cost, posing challenges for user privacy in public settings.
Innovation Solution
An LCD design featuring a first and second substrate with a liquid crystal layer, where the liquid crystal molecules are tilted at specific pretilt angles, allowing the viewing angle to be controlled by applying a bias voltage to the first electrode, enabling switching between narrow and wide viewing angles without the need for a louver shielding film or dual light source backlight system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a louver shielding film is used to narrow the viewing angle, then privacy protection is improved, but device complexity and cost increase due to additional components
Solution Approach 1:
The patent extracts the viewing angle control function from external components (louver films) and integrates it into the liquid crystal display's core structure by utilizing the liquid crystal layer's inherent properties and electrode configurations, thereby eliminating the need for additional shielding components
Solution Approach 2:
The patent replaces the mechanical/optical shielding approach (louver films) with an electrical control mechanism that uses voltage application to dynamically adjust liquid crystal molecule orientation, thereby achieving viewing angle control through electrical fields rather than physical barriers
2Adaptability or versatility
If a dual light source backlight system is used to adjust viewing angle, then viewing angle control is improved, but thickness and cost increase remarkably
Solution Approach 1:
The patent makes the liquid crystal layer and electrode system multi-functional by enabling them to perform both the primary display function and the viewing angle control function through a single integrated structure, eliminating the need for separate backlight systems
Solution Approach 2:
The patent merges the viewing angle control mechanism with the existing liquid crystal display structure by using the same liquid crystal layer and electrode system that are already present for display operations, thereby combining multiple functions into a unified structure without adding thickness
3Adaptability or versatility
If a dual light source backlight system is used to adjust viewing angle, then viewing angle control is improved, but cost increases due to additional components
Solution Approach 1:
The patent enables the liquid crystal layer and electrode system to serve multiple purposes - both display generation and viewing angle control - thereby eliminating the need for separate dual light source systems and reducing overall manufacturing cost
Solution Approach 2:
The patent extracts the viewing angle control capability from expensive additional components (dual light source systems) and implements it through the existing liquid crystal and electrode structures that are already part of the display assembly
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 easy switching between narrow and wide viewing angles by adjusting the liquid crystal molecule tilt, improving contrast and reducing light leakage, thus enhancing user privacy without increasing the LCD's thickness or cost.
Implementation Method 1
The liquid crystal molecules adjacent to the first alignment film are tilted at a first pretilt angle. The liquid crystal molecules adjacent to the second alignment film are tilted at a second pretilt angle.
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 to cause the liquid crystal molecules of the liquid crystal layer to rotate.
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. The second substrate is provided with a second electrode, a third electrode and a second alignment film. The liquid crystal molecules adjacent to the first alignment film are tilted at a first pretilt angle. The liquid crystal molecules adjacent to the second alignment film are tilted at a second pretilt angle. The second pretilt angle is in the range of 30° to 50°, and the first pretilt angle is in the range of 0° to 5°. When no bias voltage is applied to the first electrode, the LCD is displayed with a narrow viewing angle; and when a bias voltage is applied to the first electrode, the LCD is displayed with a wide viewing angle.