In-cell Touch Screen Barrier and Electrode Segmentation
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Solution Overview
Problem
Existing OLED-based touch-control display apparatuses face challenges in integrating touch functionality within the display panel due to stringent requirements for organic materials, particularly with the vacuum evaporation process making perforation and pattern segmentation difficult and costly, leading to increased thickness and complexity.
Innovation Solution
An in-cell touch screen design where a pixel region is surrounded by a first barrier with different height portions, allowing a second electrode to expand and connect externally, and utilizing inkjet printing for electrode formation to reduce parasitic capacitance and enhance touch-control capability, with a double-wall structure and varying barrier heights for precise layer formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum evaporation process is used for OLED fabrication, then OLED performance is improved, but perforation and pattern segmentation become difficult and expensive
Solution Approach 1:
The pixel electrode is divided into multiple segments (first pixel electrode segment, second pixel electrode segment, third pixel electrode segment) that are electrically connected through conductive bridges. This segmentation allows the electrode to extend across barrier structures and achieve the desired pattern without requiring complex vacuum evaporation processes for perforation.
Solution Approach 2:
Conductive bridges serve as intermediary structures that electrically connect the segmented pixel electrode portions. These bridges enable current flow between electrode segments while maintaining insulation from adjacent pixels through the barrier structures, solving the connectivity problem without complex fabrication.
2Ease of manufacture
If on-cell structure with separate bonding is used, then OLED and touch panel can be manufactured separately, but overall thickness increases and encapsulation complexity increases
Solution Approach 1:
The touch control electrode and pixel electrode are merged into a single integrated electrode structure. The pixel electrode segments and their connections form both the OLED pixel structure and the touch control electrode, eliminating the need for separate touch panel bonding and reducing overall device thickness.
3Adaptability or versatility
If in-cell touch control is implemented with traditional fabrication, then touch function is integrated in OLED, but manufacturing complexity and cost increase
Solution Approach 1:
The pixel electrode is segmented into multiple portions connected by conductive bridges, allowing the electrode to navigate around barrier structures and achieve both pixel definition and touch control functionality using standard fabrication techniques rather than complex vacuum evaporation processes.
Solution Approach 2:
Different portions of the electrode structure have different functions: the main electrode segments provide pixel control, while the conductive bridges provide both electrical connection and touch control electrode functionality. This local differentiation enables dual functionality from a single structure.
Data Source
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Figure 3A
AI summary
An in-cell touch screen, a manufacturing method thereof and a display apparatus are provided. The touch screen comprises a pixel region (100) disposed over a base substrate (001). The pixel region (100) is surrounded by a first barrier (007), which is configured to insulate the pixel region (100). The pixel region (100) includes a first electrode (002), a light-emitting layer (003) disposed over the first electrode (002), and a second electrode (004) disposed over the light-emitting layer (003). The second electrode (004) expands over an opening of the first barrier (007) so as to be able to electrically connect with a third electrode outside the pixel region (100).