Touch Pad Layout for Laser-Sealed Display Substrates

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Solution Overview

Problem

The challenge in existing display devices is that laser sealing is not smoothly performed on substrates with a touch signal pad due to its overlap with the sealing region, leading to bonding failures between the upper and lower substrates.

Innovation Solution

The touch signal pad is positioned in a non-display region, away from the sealing region, with a conductive layer made of opaque metal, and a sealing member is placed in the non-display region to ensure proper bonding between the substrates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a touch signal pad is formed on the upper substrate to enable touch screen functionality, then the device achieves integrated touch screen panel display capability, but the laser sealing process cannot be smoothly performed due to overlap with the sealing region

Engineering Contradiction:
Improvetouch screen functionalityVSAvoidbonding properties
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The touch signal pad terminal is extended in the planar dimension to position its distal end beyond the sealing member, allowing the pad to reach the touch flexible printed circuit board while keeping the bonding region clear for laser sealing. This dimensional extension resolves the spatial conflict between touch functionality and sealing reliability.

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

2Ease of operation

If the touch signal pad terminal is positioned to reach the touch flexible printed circuit board, then electrical connection is achieved, but the terminal overlaps with the sealing member causing laser sealing failure

Engineering Contradiction:
Improveelectrical connectionVSAvoidsealing precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The upper substrate is divided into distinct functional regions: a sealing region for laser bonding, a touch electrode region for touch sensing, and a touch signal pad terminal region for electrical connection. This segmentation allows each region to perform its function without interference, with the pad terminal extending beyond the sealing member to connect to the touch FPC board.

Inventive Principle:
Principle #1Segmentation

3Strength

If laser sealing is performed through the upper substrate to bond substrates, then bonding between substrates is achieved, but the presence of opaque metal in the touch signal pad blocks laser transmission

Engineering Contradiction:
Improvebonding strengthVSAvoidlaser blocking
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The touch signal pad terminal is extracted from the sealing region and positioned to extend beyond the sealing member. This extraction removes the opaque metal pad from the laser transmission path, allowing laser sealing to proceed smoothly through the upper substrate while the pad terminal remains available for electrical connection to the touch FPC board.

Inventive Principle:
Principle #2Taking out (Extraction)

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 configuration improves bonding properties between the upper and lower substrates by preventing interference from the touch signal pad during laser sealing, enhancing the structural integrity of the display device.

Implementation Method 1

laser sealing may be used to irradiate a laser with a frit interposed between the upper and lower substrates in order to bond the glass members

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

the touch pad may be ultrasonically bonded to an external device, for example, a touch flexible printed circuit board

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Data Source

PatentEP3855502B1Display device
Publication Date: 2025.08.27 SAMSUNG DISPLAY CO LTD
  • EP3855502B1 patent drawingFigure 1
  • EP3855502B1 patent drawingFigure 2
  • EP3855502B1 patent drawingFigure 3

AI summary

A display device is provided. A display device according to an exemplary embodiment, which includes a display region and a non-display region surrounding the display region, comprises: a first substrate; a second substrate facing the first substrate, and including a first surface that faces the first substrate and a second surface that is the opposite surface of the first surface of the second substrate; a touch electrode disposed on the second surface of the second substrate, and positioned in the display region; a touch pad terminal disposed on the second surface of the second substrate, positioned in the non-display region, and electrically connected to the touch electrode; and a sealing member interposed between the first substrate and the second substrate, and coupling the first substrate and the second substrate, wherein the sealing member is positioned in the non-display region, and the touch pad terminal is disposed more inwardly than the sealing member.