Display Substrate Edge Notches for Narrow-Bezel Backside Routing

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Solution Overview

Problem

Conventional display technologies require a large border area for electrical connections, limiting the active display area and causing space inefficiencies, especially when using flexible circuits to connect to a backside control circuit.

Innovation Solution

The method involves patterning the display substrate with notches along its edge to route signal lines over the edge, allowing for backside bonding of the control circuit without the need for a large border, using photolithography and a conductive adhesive layer for secure connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a large border area is used for electrical connections, then reliable electrical connection between control circuit and display substrate is achieved, but the active display area is reduced and space efficiency deteriorates

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidactive display area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent moves electrical connections from the traditional planar arrangement (on the front surface border) to a three-dimensional configuration by routing signal lines through notches cut into the substrate edge, allowing connections to be made on the backside of the display substrate. This dimensional transition enables the active display area to extend to the very edge of the substrate while maintaining reliable electrical connections through the notch structures.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If flexible circuits are used to wrap around the edge for backside control circuit connection, then electrical connection is achieved, but the border area requirement increases and space efficiency decreases

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidborder area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent extracts the electrical connection function from the traditional flexible circuit wrapper and integrates it directly into the substrate structure itself. By forming notches in the substrate edge and routing signal lines through these notches to the backside, the invention eliminates the need for separate flexible circuit components, thereby reducing border area requirements while maintaining connection reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Area of stationary object

If the entire substrate width is used for signal lines, then space efficiency and active area are improved, but trace line routing limitations arise without edge notches

Engineering Contradiction:
Improveactive display areaVSAvoidtrace line routing complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent segments the substrate edge by creating multiple notches along the perimeter, allowing signal lines to be routed through these discrete segments. This segmentation enables trace lines to traverse the entire substrate width by passing through the notched edges, eliminating routing limitations while maintaining a simple and systematic trace line configuration.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3698211B1Display substrate edge patterning and metallization
Publication Date: 2024.08.14 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3698211B1 patent drawingFigure 1~2
  • EP3698211B1 patent drawingFigure 3
  • EP3698211B1 patent drawingFigure 4

AI summary

A display includes a display substrate having a patterned edge, the patterned edge including a plurality of notches. The display further includes a plurality of display signal lines supported by the display substrate on a first side of the display substrate, and a display control circuit disposed along a second side of the display substrate, the second side being opposite the first side. The display control circuit includes a plurality of contacts. Each display signal line of the plurality of display signal lines is disposed in a respective notch of the plurality of notches to traverse the patterned edge to establish an electrical connection between each display signal line of the plurality of display signal lines and a respective contact of the plurality of contacts.