Rollable Display Device Roller Mechanism for Film Protection

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Solution Overview

Problem

Rollable display devices face issues with damage to flexible films and printed circuit boards due to repetitive winding and unwinding, stress on the display panel, delamination between the flexible film and panel, and heat management in driver ICs.

Innovation Solution

The design incorporates a roller with flat and curved portions to maintain a flat pad area, reducing contact failure and stress, and includes a film cover and buffer pad to absorb shock and manage heat efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the display device is wound and unwound repeatedly, then the rollable display function is achieved, but damage to the flexible film and printed circuit board increases

Engineering Contradiction:
Improverollable display functionVSAvoiddamage to flexible film and printed circuit board
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces a buffer pad positioned between the pad area and the flexible film that absorbs shock and stress before they can damage the flexible film and printed circuit board. This cushioning element is pre-installed to protect against repetitive winding and unwinding damage, directly resolving the contradiction between achieving rollable function and preventing component damage.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Volume of moving object

If the display device is wound around a roller, then compact storage is achieved, but stress on the display panel increases

Engineering Contradiction:
Improvestorage volumeVSAvoidstress on display panel
Core Design Contradiction:
Volume of moving objectVSStress or pressure

Solution Approach 1:

The patent applies different structural qualities to different regions of the display device. The pad area is designed with a buffer pad for shock absorption, while the display panel area maintains its structural integrity. This localized quality differentiation allows the device to be wound compactly while protecting the display panel from excessive stress.

Inventive Principle:
Principle #3Local quality

3Reliability

If the flexible film is bonded to the display panel, then electrical connection is achieved, but delamination occurs when wound around a roller

Engineering Contradiction:
Improveelectrical connectionVSAvoidbonding stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The buffer pad serves as an intermediary element between the pad area and the flexible film. It mediates the mechanical stress and tension that would otherwise cause delamination, allowing the flexible film to remain bonded to the display panel while accommodating the stresses of winding and unwinding through its shock-absorbing properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Extent of automation

If the driver IC is mounted on the flexible film, then display control is achieved, but heat generation causes performance degradation

Engineering Contradiction:
Improvedisplay control functionVSAvoidheat from driver IC
Core Design Contradiction:
Extent of automationVSTemperature

Solution Approach 1:

The patent utilizes the flexible film as a thermal management medium. The flexible film with its large surface area acts as a heat dissipation pathway for the driver IC, allowing heat to be distributed and dissipated across the flexible structure, thereby preventing localized overheating and performance degradation while maintaining the automated display control function.

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP3819743B1Flexible display device
Publication Date: 2022.04.27 LG DISPLAY CO LTD
  • EP3819743B1 patent drawingFigure 1A
  • EP3819743B1 patent drawingFigure 1B
  • EP3819743B1 patent drawingFigure 2

AI summary

There is provided a display device (100, 1000, 1100, 1200, 1300, 1400) including: a display panel (120); a back cover (110) supporting the display panel (120) on a rear surface of the display panel (120); one or more flexible films (130) electrically connected to one end of the display panel (120) and disposed on a surface of the back cover (110); a film cover covering the one or more flexible films (130) and the end of the display panel (120); a printed circuit board (140) electrically connected to the one or more flexible films (130) and disposed on the surface of the back cover (110); and a roller (171) comprising a first flat portion (171Fa), a second flat portion (171Fb) and a curved portion (171R). The display panel (120) and the back cover (110) are wound around or unwound from the roller (171). The end of the display panel (120) is disposed in line with the first flat portion (171Fa) while the printed circuit board (140) is disposed in line with the second flat portion (171Fb) when the display panel (120) and the back cover (110) are fully wound around the roller (171). Accordingly, the end of the display panel (120) to which at least one flexible film (130) is bonded remains flat all the time, so that damage to the at least one flexible film (130) and the display panel (120) can be reduced while the display device (100, 1000, 1100, 1200, 1300, 1400) is wound or unwound.