Switchable Viewing Angle LCD with VAC Sub-pixels
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Solution Overview
Problem
Conventional viewing angle switchable display technologies compromise on display quality, thickness, weight, or convenience in switching between wide and narrow viewing angle modes, failing to effectively prevent information leakage to side viewers.
Innovation Solution
A liquid crystal display panel with twisted nematic liquid crystal molecules and a unique electrode structure that allows switching between wide and narrow viewing angle modes by controlling electric fields within the liquid crystal layer, using viewing angle control sub-pixels to enhance luminance in wide mode and create side light leakage in narrow mode for anti-peeking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If anti-peeking films are added to displays, then side viewing luminance is suppressed, but display quality and optical properties are degraded
Solution Approach 1:
The display panel is segmented into different pixel types: normal color sub-pixels for front viewing and viewing angle control (VAC) sub-pixels for controlling side viewing luminance. This segmentation allows independent optimization of front display quality and side viewing suppression without mutual interference.
Solution Approach 2:
Different regions of the display have different optical properties. The VAC sub-pixels are designed with specific liquid crystal alignment and electrode configurations that create different light emission characteristics compared to normal sub-pixels, enabling localized control of viewing angle properties.
2Adaptability or versatility
If voltage-controllable diffusion films are used to control backlight, then switching between wide and narrow viewing angles is enabled, but side viewing luminance cannot be completely suppressed
Solution Approach 1:
The liquid crystal molecules in VAC sub-pixels change their orientation state based on applied voltage, transitioning between different alignment configurations. This parameter change enables dynamic control of light emission angle and intensity, achieving both wide and narrow viewing angle modes with effective side viewing suppression.
3Adaptability or versatility
If an extra viewing angle control module is added, then viewing angle switching is achieved, but device thickness and weight are doubled
Solution Approach 1:
The viewing angle control functionality is merged into the existing display panel structure by integrating VAC sub-pixels within the same liquid crystal layer and electrode system. This eliminates the need for separate control modules, maintaining thin profile while achieving dual-mode viewing angle control.
Solution Approach 2:
The liquid crystal layer serves multiple functions simultaneously: it provides the primary display function through color sub-pixels and the viewing angle control function through VAC sub-pixels. This multi-functionality is achieved by using the same liquid crystal material and electrode structure for both purposes.
4Object-affected harmful factors
If viewing angle control sub-pixels provide side light leakage in narrow mode, then anti-peeking effect is achieved, but front viewing luminance may be affected
Solution Approach 1:
Instead of suppressing side viewing luminance by blocking light paths (conventional approach), the invention inverts the approach by using VAC sub-pixels to emit light specifically in side viewing directions through controlled liquid crystal alignment. This creates the anti-peeking effect by active side light emission rather than passive suppression, while normal sub-pixels maintain front viewing luminance.
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 seamless switching between wide and narrow viewing angle modes without compromising display quality or increasing weight/thickness, effectively preventing information leakage to side viewers while maintaining luminance and image quality.
Implementation Method 1
The liquid crystal molecules of each color sub-pixel include twisted nematic (TN) liquid crystal molecules
Implementation Method 2
switching between wide and narrow viewing angle modes by controlling electric fields within the liquid crystal layer
Implementation Method 3
Each of the color sub-pixels includes a first electrode disposed on an inner side of the first substrate facing the second substrate, and a second electrode disposed on an inner side of the second substrate facing the first substrate
Data Source
AI summary
A viewing angle switchable liquid crystal display panel includes a first substrate, a second substrate, a liquid crystal layer disposed between the first substrate and the second substrate, a plurality of color sub-pixels and a plurality of viewing angle control (VAC) pixels. The liquid crystal layer includes liquid crystal molecules sandwiched between the first substrate and the second substrate. The liquid crystal molecules of each color sub-pixel include twisted nematic liquid crystal molecules. Each of the color sub-pixels includes a first pixel electrode disposed on an inner surface of the first substrate, and a second pixel electrode disposed on an inner surface of the second substrate. Each of the viewing angle control pixels includes a first electrode and a second electrode disposed on the inner surface of the first substrate, and a third electrode disposed on the inner surface of the second substrate.