Switchable Viewing Angle Liquid Crystal Display with Dynamic Refresh
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Solution Overview
Problem
Conventional liquid crystal display devices with single viewing angle modes fail to meet user needs for both wide and narrow viewing angles, particularly in scenarios requiring privacy protection, leading to issues like uneven display, image sticking, and flicker when switching between modes.
Innovation Solution
A liquid crystal display device with a switchable viewing angle capability, utilizing a viewing angle control electrode and a display control module that adjusts image refresh frequency and voltage output to switch between wide and narrow viewing angles, applying a direct current voltage in wide mode and a periodic alternating voltage in narrow mode, with the image refresh frequency being twice or four times the data input frequency in narrow mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a vertical electric field is applied to switch to narrow viewing angle mode, then privacy protection is improved, but display uniformity deteriorates due to mura and image sticking
Solution Approach 1:
The patent applies periodic alternating voltage to the viewing angle control electrode instead of constant DC voltage. The voltage alternates between positive and negative polarity at frequencies of 50Hz, 60Hz, 70Hz, 80Hz, 90Hz, or 100Hz, which prevents liquid crystal molecules from maintaining a fixed tilted state that causes mura and image sticking, while still achieving narrow viewing angle effect during the charged intervals
Solution Approach 2:
The patent changes the voltage type from DC to AC with specific frequency parameters (50-100Hz range). This parameter change allows the liquid crystal molecules to dynamically respond to alternating fields, achieving privacy protection through periodic reorientation while avoiding the harmful effects of static high-voltage states that cause display non-uniformity
2Device complexity
If conventional timing controller with fixed 60Hz refresh rate is used, then device complexity is reduced, but display quality deteriorates with flicker and image sticking
Solution Approach 1:
The patent introduces dynamic frequency adjustment capability to the timing controller, allowing it to switch between 60Hz and higher refresh rates (120Hz, 144Hz, 165Hz, 180Hz, 200Hz, 240Hz) based on the selected viewing angle mode. This dynamic adaptation enables high-quality display in narrow viewing angle mode while maintaining simple operation
Solution Approach 2:
The patent changes the image refresh frequency parameter from fixed 60Hz to variable frequencies (120Hz, 144Hz, 165Hz, 180Hz, 200Hz, 240Hz) when narrow viewing angle mode is activated. This parameter adjustment synchronizes with the AC voltage frequency applied to the viewing angle control electrode, eliminating flicker and image sticking artifacts
3Ease of operation
If DC voltage is applied to viewing angle control electrode, then ease of operation is improved with simple voltage output, but display stability deteriorates causing image sticking
Solution Approach 1:
The patent replaces simple DC voltage with periodic AC voltage that alternates polarity at 50-100Hz. This periodic action maintains ease of operation through automated controller implementation while preventing display instability by continuously refreshing the liquid crystal molecule orientation, eliminating image sticking caused by static DC fields
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
This solution effectively alleviates issues like uneven display, image sticking, and flicker by rapidly changing the electric field applied to liquid crystal molecules, allowing seamless switching between wide and narrow viewing angles, enhancing operational flexibility and providing privacy protection.
Implementation Method 1
the viewing angle control electrode 111 on the first substrate 11 is applied with a voltage, which causes a large potential difference between the viewing angle control electrode 111 and the common electrode on the second substrate 12, so that the liquid crystal molecules in the liquid crystal layer 13 are tilted due to a vertical electric field
Implementation Method 2
liquid crystal molecules in the liquid crystal layer 13 are tilted due to a vertical electric field (as indicated by the arrows E) while rotating horizontally
Data Source
AI summary
A liquid crystal display device includes a display panel, a display control module and a voltage output module. The display panel includes a first substrate, a second substrate, and a liquid crystal layer between the first substrate and the second substrate. The first substrate is provided with a viewing angle control electrode. In a wide viewing angle mode, the image refresh frequency of the display panel is the same as the data input frequency of the image data inputted to the display control module, and the voltage output module outputs a direct current voltage to the viewing angle control electrode. In a narrow viewing angle mode, the image refresh frequency of the display panel is twice or four times the data input frequency of the image data inputted to the display control module, and the voltage output module outputs a periodic alternating voltage to the viewing angle control electrode.