Electrophoretic Display Driving Method for DC Balance and Image Consistency
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Solution Overview
Problem
The partial-screen drive method for electrophoretic display apparatuses can result in variations in image size and color tone due to the spreading of electrophoretic particles, leading to smeared or contracted images, and may cause a decrease in local contrast ratio and afterimages, affecting long-term reliability and display quality.
Innovation Solution
The method involves adding image adjustment steps to the partial-screen drive process, where the background of an image is displayed in a different color, and the image is redrawn in its original color, ensuring DC balance by adjusting the voltage-time product in each step, and incorporating single-color display steps to minimize pattern boundary lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the partial-screen drive method is used to shorten the drive period, then the productivity is improved, but the manufacturing precision deteriorates due to variations in image size and color tone
Solution Approach 1:
The patent applies preliminary action by performing a background display step before the main image display step. This background step pre-positions particles in the background region, preventing them from spreading during the subsequent image display. By preparing the background state in advance, the method eliminates the need for lengthy full-screen rewriting while maintaining image precision.
Solution Approach 2:
The patent segments the display update process into distinct regions: background regions that require only background color particles and image regions that require image color particles. This segmentation allows different parts of the screen to be updated with appropriate particle sets, preventing cross-contamination and maintaining both speed and precision.
2Productivity
If the partial-screen drive method is used, then the productivity is improved, but the reliability deteriorates due to DC imbalance
Solution Approach 1:
The patent changes the voltage application parameters by introducing a background display step with specific voltage polarity opposite to the main image display step. This parameter change ensures that the total voltage-time product over one frame period equals zero, achieving DC balance while maintaining the benefits of partial-screen driving.
3Manufacturing precision
If the full-screen drive method is used to maintain image quality, then the manufacturing precision is improved, but the productivity deteriorates due to longer update time
Solution Approach 1:
The patent applies partial action by rewriting only the necessary portions of the display: background regions receive background color particles and image regions receive image color particles. This selective partial updating achieves full image quality without the overhead of rewriting the entire screen, thus improving productivity while maintaining precision.
4Productivity
If the partial-screen drive method is used, then the productivity is improved, but the object-generated harmful factors increase due to particle spreading causing smeared images
Solution Approach 1:
The patent applies preliminary anti-action by first displaying the background color across the entire screen before displaying the image. This preliminary background display creates an anti-action that counterbalances the particle spreading that would otherwise occur during image display. The background particles prevent image particles from spreading into background regions, eliminating the smeared image effect.
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 reduces variations in image size and color tone, maintains DC balance, and improves display quality by preventing decreases in local contrast ratio and afterimages, ensuring long-term reliability and enhanced visual fidelity.
Implementation Method 1
an electrophoretic display apparatus including a display section configured to have the following components: a pair of substrates that sandwich an electrophoretic device containing electrophoretic particles; pixels capable of displaying at least a first color and a second color; a pixel electrode corresponding to each of the pixels and formed between one of the substrates and the electrophoretic device; and a common electrode facing the plurality of pixel electrodes and formed between the other substrate and the electrophoretic device
Data Source
AI summary
An electrophoretic display apparatus driving method that allows DC balance to be achieved and reduces variations in size and color tone of a displayed image that may occur in a partial-screen drive method and related apparatus are provided. The drive method includes a first image display step (S2) of displaying a first image in a first color on a display section, a first image adjustment step (S3) of displaying a background of the first image in a second color, a first image deletion step (S4) of displaying the background of the first image in the first color, a second image display step (S12) of displaying a background of a second image in the second color, a second image adjustment step (S13) of displaying the second image in the first color, and a second image deletion step (S14) of displaying the second image in the second color.