Electrophoretic Display Driving Method Correcting Gamma Blurring
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Solution Overview
Problem
Electrophoretic display devices face issues with blurring (blotting) due to oblique electric fields, which affect the display of gradation levels, especially when transitioning between black and white image data, leading to inaccurate representation of original image data.
Innovation Solution
A method of driving electrophoretic display devices that involves changing gradation levels based on correction data, converting image data into dithering patterns for each predetermined region, and driving electrophoretic particles accordingly, taking into account the gamma characteristic of the display section to correct for blurring and improve display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If dithering is performed without considering blotting, then the first color or second color is displayed densely (highlighted), but the gradation level becomes inaccurate compared to original image data
Solution Approach 1:
The patent applies parameter changes by modifying the gradation level of image data based on correction data that accounts for blotting characteristics. The correction data includes a correction value derived from measuring the relationship between original image data and displayed image data, allowing the gradation levels to be adjusted so that colors are displayed with appropriate density while maintaining accuracy in representing the original image data.
2Manufacturing precision
If correction data is applied to change gradation level, then display quality is improved by correcting gamma characteristic, but device complexity increases due to additional processing steps
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing correction data that characterizes the blotting and gamma characteristics of the display section before actual image display. This correction data, including correction values derived from measuring original versus displayed image data relationships, is prepared in advance and stored as lookup tables, allowing the display device to simply retrieve and apply pre-computed corrections during operation without complex real-time calculations.
3Ease of operation
If oblique electric field is applied to drive electrophoretic particles, then particles can be moved to display images, but particles from adjacent pixels are electrophoresed causing blurring
Solution Approach 1:
The patent converts the harmful effect of oblique electric field spread into a beneficial correction mechanism. By measuring the actual blurring effect (gamma characteristic) caused by the oblique electric field and incorporating this correction into the image data processing, the system compensates for the inherent particle spread. The correction data, derived from measuring the relationship between original and displayed image data, allows the system to counteract the oblique field's blurring effect and achieve sharp pixel boundaries.
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 approach allows for accurate representation of original image data by correcting the gamma characteristic of the display section, reducing blurring and enhancing display quality by ensuring that gradation levels are maintained accurately, even when transitioning between black and white.
Implementation Method 1
an electric field which is applied to the electrophoretic particles tends to spread obliquely. For this reason, the electrophoretic particles of adjacent pixels are electrophoresed
Implementation Method 2
an electrophoretic dispersion liquid contains inorganic particles and resin particles, which are colored in a color different from the color of the inorganic particles and have a charging polarity opposite to the charging polarity of the inorganic particles
Data Source
AI summary
A method of driving an electrophoretic display device includes changing the gradation level of image data on the basis of correction data corresponding to the gradation level, converting image data with the changed gradation level to a dithering pattern, in which the first color and the second color are combined, corresponding to the changed gradation level for each predetermined region of image data, and driving the electrophoretic particles of the first color and the electrophoretic particles of the second color on the basis of image data converted to the dithering pattern for the plurality of pixels in the display section.