Electrophoretic Display Double-Side Control Substrate for Refresh
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Solution Overview
Problem
Existing electrophoretic displays suffer from low aperture ratios, slow refresh speeds, and image sticking issues due to particle diffusion and voltage kickback, particularly in color displays, which affect contrast, color accuracy, and display longevity.
Innovation Solution
The electrophoretic display employs a double-side control circuit substrate with transparent conductive materials for the storage capacitor electrodes and a micro-partition structure, enhancing the aperture ratio and controlling particle movement for improved image stability and refresh speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If traditional single-side control circuit substrate is used, then manufacturing process is simpler, but aperture ratio is low and refresh speed is slow
Solution Approach 1:
The control circuit substrate is divided into two separate substrates (first control substrate and second control substrate) positioned on opposite sides of the electrophoresis layer. Each substrate independently controls one side of the display, allowing both substrates to contribute to the aperture ratio without interfering with each other's circuit layout. This segmentation resolves the contradiction by enabling higher aperture ratio while maintaining manageable complexity through modular design.
Solution Approach 2:
The control circuit substrate transitions from a single-side (2D planar) configuration to a double-side (3D spatial) configuration. By placing control circuits on both sides of the electrophoresis layer, the design utilizes the third dimension (depth/thickness) to increase the effective aperture area without increasing the planar footprint, thus resolving the contradiction between aperture ratio and structural complexity.
2Speed
If conventional driving circuit layer with amorphous silicon is used, then manufacturing cost is low, but refresh speed is slow due to low electron mobility
Solution Approach 1:
The patent changes the material parameter of the thin film transistor from amorphous silicon to polysilicon. Polysilicon has higher electron mobility (10-100 times higher than amorphous silicon), which directly improves the refresh speed of the electrophoresis display. This parameter change resolves the contradiction by achieving faster refresh speeds while still using a compatible semiconductor manufacturing process.
3Reliability
If control electrode layer is positioned far from viewing surface, then manufacturing is easier, but particle diffusion causes image sticking and reduced contrast
Solution Approach 1:
Instead of placing the control electrode layer on the traditional single side, the patent inverts the approach by positioning control electrode layers on both sides of the electrophoresis layer. This allows the control electrodes to be closer to the viewing surface on each side, reducing the distance over which particles can diffuse laterally. The inverted/double-sided configuration resolves the contradiction by improving image stability while managing layer structure complexity through symmetric design.
4Reliability
If hollow cavity structure is used for electrophoresis material, then particle containment is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent uses a flexible encapsulation layer (encapsulation film) to contain the electrophoresis material instead of rigid hollow cavities. This flexible film approach is more tolerant to manufacturing variations and does not require the high precision cavity formation processes. The flexible shell resolves the contradiction by providing adequate particle containment while reducing manufacturing precision requirements.
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 solution achieves an aperture ratio of at least 70%, significantly reducing particle diffusion and image sticking, enabling faster refresh rates and improved color accuracy and display longevity.
Implementation Method 1
an electrophoresis layer 20, a control electrode layer PEL
Implementation Method 2
a storage capacitor, one end of the storage capacitor is connected to the control electrode
Implementation Method 3
the thin film transistor made by the amorphous silicon (a-Si) process
Data Source
AI summary
An electrophoresis display double-side control circuit substrate includes a first control substrate having a first face and a second face, a first driving circuit layer and a first control electrode layer sequentially arranged on the second face, a second control substrate having a third face and a fourth face, a second driving circuit layer and a second control electrode layer sequentially arranged on the third face. The electrophoresis display includes a micro partition structure arranged between the first control substrate and the second control substrate and made from polymer material. The micro partition structure includes a plurality of partition walls to define chambers for accommodating a colloidal solution.