Liquid Crystal Display Viewing Angle Switching via Voltage Waveform Control
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Solution Overview
Problem
Liquid crystal display devices in mobile terminals face challenges in controlling viewing angles, particularly in public spaces where narrow viewing angles are required to prevent peeping, and existing technologies struggle to effectively switch between wide and narrow viewing angles without causing image sticking.
Innovation Solution
A liquid crystal display device with an active matrix substrate, a counter substrate, and a liquid crystal layer, where the control circuit switches the amplitude and waveform of the voltage applied to third electrodes to switch between wide and narrow viewing angles, and differentiates the common voltage applied to first and second electrodes in each mode to prevent image sticking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the viewing angle is widened using techniques such as UV2A, IPS, PSA, and FFS, then the viewing angle is improved, but the ability to prevent peeping in public spaces deteriorates
Solution Approach 1:
The patent implements dynamic switching between wide viewing angle mode and narrow viewing angle mode by controlling the voltage applied to the third electrode. The control circuit changes the voltage amplitude and waveform according to the selected mode, enabling the liquid crystal molecules to reorient dynamically. This resolves the contradiction by making the viewing angle adjustable rather than fixed, allowing the device to adapt to different usage scenarios (public vs. private spaces).
Solution Approach 2:
The patent changes the voltage parameters (amplitude and waveform) applied to the third electrode to switch between viewing angle modes. In wide viewing angle mode, a first voltage amplitude is applied, while in narrow viewing angle mode, a second voltage amplitude different from the first is applied. This parameter change enables the liquid crystal display to transition between different viewing characteristics, resolving the contradiction between wide viewing angle and peeping prevention.
2Adaptability or versatility
If the voltage amplitude and waveform applied to the third electrode are switched to change viewing angles, then the viewing angle control is improved, but image sticking occurs
Solution Approach 1:
The patent applies different voltage characteristics specifically to the third electrode compared to the first and second electrodes. The third electrode receives voltage with different amplitude and waveform characteristics depending on the mode, while the first and second electrodes receive compensation voltages. This localized differential voltage application prevents image sticking by ensuring that the liquid crystal molecules experience appropriate electric field conditions in different regions and modes, resolving the contradiction between viewing angle switching and image quality.
Solution Approach 2:
The patent applies compensation voltages to the first and second electrodes in advance to prevent image sticking before it occurs. When switching between viewing angle modes, the control circuit simultaneously adjusts the voltage on the third electrode and applies compensating voltages to the first and second electrodes. This preliminary compensatory action prevents the accumulation of residual effects that would cause image sticking, while still enabling viewing angle switching.
3Device complexity
If a common voltage is applied to the first electrode or second electrode in both viewing angle modes, then the circuit design is simplified, but image sticking occurs due to insufficient voltage differentiation
Solution Approach 1:
The patent changes the common voltage parameter applied to the first electrode or second electrode depending on the viewing angle mode. In wide viewing angle mode, a first common voltage is applied, while in narrow viewing angle mode, a second common voltage different from the first is applied. This parameter differentiation ensures that the voltage conditions are sufficiently distinct between modes to prevent image sticking, while still maintaining a relatively simple circuit architecture by using a common voltage line.
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 can effectively switch between wide and narrow viewing angles, suppressing image sticking by adjusting the voltage applied to the electrodes, ensuring privacy in public spaces while maintaining image quality.
Implementation Method 1
an active matrix substrate including at least one first electrode and at least one second electrode configured to generate a transverse electrical field
Implementation Method 2
a counter substrate including a plurality of third electrodes disposed at predetermined intervals and having a stripe pattern
Implementation Method 3
A liquid crystal display device displays an image by controlling a transmission amount of light, using the alignment of liquid crystal molecules
Data Source
AI summary
A liquid crystal display device includes: an active matrix substrate including a first electrode and a second electrode configured to generate a transverse electrical field; a counter substrate including a plurality of third electrodes disposed at predetermined intervals and having a stripe pattern; a liquid crystal layer located between the active matrix substrate and the counter substrate; and a control circuit. The liquid crystal display device can display an image in a first viewing angle mode and a second viewing angle mode having a viewing angle narrower than the first viewing angle mode by the control circuit switching an amplitude and a waveform of a voltage applied to the third electrodes. The control circuit applies a common voltage having a different value to the first electrode or the second electrode in each of the first viewing angle mode and the second viewing angle mode.