Selective Microcapsule Dispensing for Electrophoretic Display Substrates
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Solution Overview
Problem
Existing electrophoretic display devices face material waste and reduced display characteristics due to the need to coat microcapsules on entire substrates, including non-display areas, and the inefficiency of microcapsule distribution methods, which also lowers productivity.
Innovation Solution
A display device and manufacturing method where microcapsules are selectively disposed only on the display area between substrates, with the background area colored to serve as a background, eliminating the need for microcapsule removal and simplifying the circuit construction, using a dispenser for precise microcapsule placement and lyophilic/lyophobic processes for accurate positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the microcapsule is coated on the whole surface of the substrate, then the microcapsule is coated on both the display area and the background area, but this causes material waste and requires subsequent removal from non-display areas
Solution Approach 1:
The patent applies local quality by differentiating the treatment of display area versus background area. The display area receives microcapsule coating for active display function, while the background area is colored with background color without microcapsule coating. This selective application eliminates material waste while maintaining display functionality.
Solution Approach 2:
The patent segments the substrate surface into display area and background area, applying different treatments to each. The display area is coated with microcapsule material, while the background area is colored with background color. This segmentation allows independent optimization of each region's properties.
2Ease of manufacture
If the microcapsule is coated on the background area, then the background can be formed, but the microcapsule must be removed later which damages the common electrode and lowers display characteristics
Solution Approach 1:
The patent applies local quality by differentiating the treatment of display area versus background area. The display area receives microcapsule coating for active display function, while the background area is colored with background color without microcapsule coating. This selective application eliminates material waste while maintaining display functionality.
Solution Approach 2:
The patent extracts the microcapsule coating step from the background area processing. Instead of coating microcapsules on the entire substrate and then removing them from the background area, the patent directly applies background color to the background area without microcapsule coating, eliminating the harmful removal step that damages the common electrode.
3Quantity of substance
If the microcapsule is coated on the whole substrate, then complete coverage is achieved, but this increases manufacturing time and reduces productivity
Solution Approach 1:
The patent applies local quality by differentiating the treatment of display area versus background area. The display area receives microcapsule coating for active display function, while the background area is colored with background color without microcapsule coating. This selective application eliminates material waste while maintaining display functionality.
Solution Approach 2:
The patent segments the substrate surface into display area and background area, applying different treatments to each. The display area is coated with microcapsule material, while the background area is colored with background color. This segmentation allows independent optimization of each region's properties.
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 material waste, prevents damage to electrodes, enhances display characteristics, and increases productivity by ensuring microcapsules are only on necessary areas, allowing for uniform film thickness and improved display performance.
Implementation Method 1
an electrophoretic display device which has an electrophoretic dispersion liquid including a liquid dispersion medium and electrophoretic particles is known. When an electric field is applied to the electrophoretic dispersion liquid, a distribution of the electrophoretic particles is changed and an optical characteristic of the electrophoretic dispersion liquid changes
Implementation Method 2
the microcapsule is coated on a whole surface of a substrate on which a common electrode is formed. Then, a substrate on which a pixel electrode is formed is bonded on the coated surface of the microcapsule so as to be laminated
Data Source
AI summary
A display device including: a first substrate having a pixel electrode; a second substrate having a common electrode; a microcapsule sandwiched between the first substrate and the second substrate; and a display material changing its optical characteristic in response to an electrical stimulation, the display material being encapsulated in the microcapsule, the microcapsule being selectively disposed on a display area formed by the pixel electrode in between the first substrate and the second substrate, and a background area of one of the first substrate and the second substrate being colored with a background color, the background area serving as a background with respect to the display area.