Liquid Crystal Driving Method for Ionic Impurity Sweeping
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Solution Overview
Problem
Existing methods for suppressing the effects of ionic impurities in liquid crystal devices, such as those used in projection type display devices, have poor flushing efficiency due to low voltage applied by horizontal electric fields and lack specific methods for varying voltage values across regions.
Innovation Solution
A driving method for electro-optical devices involves applying signals with delayed phases to pixel electrodes, creating a migrating electric field that sweeps ionic impurities from the center towards the outer edges of the effective pixel region, using a combination of first, second, and third signals with specific phase delays and frequencies to efficiently remove both positive and negative ionic impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a horizontal electric field is applied by changing the amplitude for each region to sweep ionic impurities, then ionic impurities can be removed from the effective pixel region, but the voltage of the electric field is small resulting in poor flushing efficiency
Solution Approach 1:
The patent changes the parameter of voltage amplitude across different regions to solve the contradiction. By setting different amplitude values for horizontal electric fields in different regions (with outer regions having larger amplitudes than inner regions), the patent achieves both sufficient flushing efficiency in high-impurity outer regions and adequate display quality in the effective pixel region, resolving the trade-off between reliability and productivity.
2Reliability
If a horizontal electric field is applied to sweep ionic impurities to outer regions, then ionic impurities are removed from the effective pixel region, but no specific method is disclosed for causing voltage values to differ for each region
Solution Approach 1:
The patent divides the display panel into multiple horizontal regions (first region, second region, third region) and applies different amplitude values for electric fields in each region. This segmentation approach provides a specific, implementable method for varying voltage values across regions, making the control method concrete and manageable while achieving effective impurity removal without excessive complexity.
3Illumination intensity
If high luminous flux density is used in projection type display devices, then display brightness is improved, but ionic impurities are generated through photochemical reactions and exhibit harmful effects on display
Solution Approach 1:
The patent converts the harmful effect of ionic impurities into a beneficial outcome by applying horizontal electric fields that actively sweep impurities generated by high-luminosity operation toward outer regions. The high luminous flux density that generates impurities is thus paired with an active removal mechanism, transforming the harmful byproduct into a manageable condition that doesn't degrade display quality.
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 method effectively sweeps ionic impurities to the outer edges, reducing their impact on the display and preventing display defects, while maintaining high display quality by utilizing AC signals with phase delays and appropriate frequencies to align with the migration of impurities.
Implementation Method 1
an electro-optical layer that is disposed between the first substrate and the second substrate
Implementation Method 2
sweep up ionic impurities that are included inside the electro-optical layer in the direction of the second wiring from the first wiring
Data Source
AI summary
Provided are a driving method of an electro-optical device, an electro-optical device and an electronic apparatus in which reductions in display quality are suppressed. The driving method of an electro-optical device that is provided with an element substrate, a facing substrate, and a liquid crystal layer that is disposed between the element substrate and the facing substrate, includes applying an AC signal V1 to a plurality of first pixel electrode that are electrically connected to a first scanning line of the element substrate 10, and applying an AC signal V2 to a plurality of second pixel electrodes that are electrically connected to a second scanning line, which is disposed adjacent to the first scanning line, and the phase of the AC signal V2 is delayed by a predetermined amount with respect to that of the AC signal V1.