Viewing Angle Switchable Device Using Liquid Crystal and Polarizers
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Solution Overview
Problem
Conventional display devices with wide viewing angles can inadvertently reveal private information to others, and existing solutions like light control films are inconvenient to use for switching between wide and narrow viewing angles.
Innovation Solution
A viewing angle switchable device comprising an absorptive polarizer, a reflective polarizer, and an electrically controlled viewing angle switching element with liquid crystal molecules, which can be controlled to adjust the viewing angle by applying a voltage, allowing the device to switch between a general display mode and a peep-avoiding mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light control film is placed in front of a display to filter out wide-angled beams, then privacy protection is improved, but ease of operation deteriorates due to manual placement and removal requirements
Solution Approach 1:
The patent replaces the mechanical system of manually placing and removing light control films with an electrically controlled liquid crystal layer system. The liquid crystal layer can be switched between transparent and opaque states through voltage control, automatically adjusting the viewing angle without manual intervention. This substitution of mechanical operation with electrical control resolves the contradiction by maintaining privacy protection while dramatically improving ease of operation.
Solution Approach 2:
The patent implements a dynamic viewing angle control system using liquid crystal technology. The liquid crystal layer can dynamically change its optical properties (from transparent to opaque) in response to electrical signals, allowing the display to adapt its viewing angle characteristics in real-time. This dynamic capability enables automatic privacy protection without requiring manual film replacement, thus resolving the operational convenience issue.
2Adaptability or versatility
If the viewing angle of a display is made wide, then adaptability is improved, but privacy protection worsens due to information leakage
Solution Approach 1:
The patent employs a dynamic liquid crystal layer that can change its optical state based on electrical control signals. When voltage is applied, the liquid crystal molecules reorient to either allow light passage (wide viewing angle mode) or block light (narrow viewing angle/privacy mode). This dynamic switching capability enables the display to adapt between wide viewing angle and privacy protection modes as needed, resolving the contradiction between adaptability and privacy protection.
Solution Approach 2:
The patent changes the optical parameters of the liquid crystal layer through electrical control. By adjusting the voltage applied to the liquid crystal layer, the optical properties (transparency, viewing angle) are changed. This allows the display to switch between different viewing angle states, enabling both wide viewing angle operation and privacy-protected operation, thus resolving the contradiction between adaptability and privacy protection.
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 device effectively narrows the viewing angle range, reducing light leakage and preventing unauthorized viewing by reflecting or absorbing light beams at large angles, thus enhancing privacy while allowing convenient electrical control of the viewing mode.
Implementation Method 1
The electrically controlled viewing angle switching element includes two transparent substrates, two transparent conductive layers disposed between the two transparent substrates, and a liquid crystal layer disposed between the two transparent conductive layers. The liquid crystal layer includes a plurality of liquid crystal molecules. When there is a difference in the potentials of the two transparent conductive layers, an orthogonal projection of an optical axis of each of the plurality of liquid crystal molecules on the absorptive polarizer is parallel to or perpendicular to the transmission axis of the absorptive polarizer and the transmission axis of the reflective polarizer.
Implementation Method 2
A phase delay is caused in an environmental light beam which enters the viewing angle switchable device by a large angle, causing the environmental light beam to be reflected by the reflective polarizer.
Implementation Method 3
A phase delay is caused in a display light beam which enters the viewing angle switchable device by a large angle may not pass through the absorptive polarizer (i.e. may be absorbed by the absorptive polarizer).
Data Source
AI summary
A viewing angle switchable device including an absorptive polarizer, a reflective polarizer and an electrically controlled viewing angle switching element is provided. A transmission axis of the reflective polarizer is parallel to a transmission axis of the absorptive polarizer. The electrically controlled viewing angle switching element is disposed between the absorptive polarizer and the reflective polarizer and includes two transparent substrates, two transparent conductive layers and a liquid crystal layer including a plurality of liquid crystal molecules. When there is a potential difference between the two transparent conductive layers, an orthogonal projection of an optical axis of each of the plurality of liquid crystal molecules on the absorptive polarizer is parallel to or perpendicular to the transmission axis of the absorptive polarizer and the transmission axis of the reflective polarizer. A viewing angle switchable display module including the viewing angle switchable device is also provided.