In-Cell Touchscreen Wiring via Edge Contact Structure
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Solution Overview
Problem
The organic electroluminescent display device's upper electrode extending over the entire display area makes it difficult to create a contact structure connecting wiring layers above and below the OLED, limiting the configuration of touchscreens to the on-cell type, which hinders component reduction and flexibility.
Innovation Solution
A touchscreen design incorporating a substrate with light-emitting elements, upper and lower inorganic films, and a touch sensor with sensor wiring connected through an inorganic film joining portion, allowing for an in-cell type configuration by electrically connecting the sensor wiring with the lower-layer wiring in the outer edge area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a contact structure is provided to connect wiring layers above and below the OLED, then wiring sharing and component reduction are enabled, but the upper electrode extending over the entire display area prevents this connection
Solution Approach 1:
The patent moves the contact structure from the display area to the outer edge area, utilizing the spatial dimension outside the OLED region. This allows vertical wiring connection through the inorganic films without interfering with the upper electrode's continuous coverage over the display area, thus enabling wiring sharing while maintaining OLED structure integrity.
Solution Approach 2:
The patent introduces an intermediary contact structure consisting of contact holes through the inorganic films and conductive plugs, which mediates the electrical connection between sensor wiring and display wiring. This intermediary pathway enables wiring sharing without requiring direct access to the upper electrode over the display area.
2Stability of the object's composition
If an on-cell type touchscreen configuration is used, then the upper electrode can extend over the entire display area, but the number of components increases and flexibility is reduced
Solution Approach 1:
The patent merges the sensor wiring and display wiring into a single shared wiring layer by establishing electrical connection through the contact structure in the outer edge area. This allows both the touch sensor and display to share common FPC connections, reducing the total number of FPCs from two to one, while the upper electrode maintains its continuous coverage over the display area.
3Ease of manufacture
If connection terminals are provided in the display area, then wiring connection is simplified, but the display area is occupied and effective display space is reduced
Solution Approach 1:
The patent extracts the contact structure from the display area and relocates it to the outer edge area. This separation removes the connection terminals from the active display region, preventing occupation of display area, while still providing simplified wiring connection through the contact holes and conductive plugs in the peripheral region.
Data Source
AI summary
A touchscreen includes an OLED, upper-layer inorganic films on the OLED, a lower-layer inorganic film stacked between the OLED and a substrate, and a touch sensor on the upper-layer inorganic film. The upper-layer inorganic films and the lower-layer inorganic film extend over a display area and a picture-frame area. A lower-layer wiring is formed of a conductive film stacked between the OLED and the substrate. A sensor wiring is formed of a conductive film on the upper-layer inorganic film. An inorganic film joining portion where the upper-layer inorganic films and the lower-layer inorganic film are directly joined together or joined together with another inorganic material interposed therebetween is provided in the picture-frame area. A contact portion that electrically connects the sensor wiring with the lower-layer wiring is provided, in a plan view, in the inorganic film joining portion or an area on the outside thereof.