Display Device Printed Layer Conceals FPCB Bubbles
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Solution Overview
Problem
The integration of a flexible printed circuit board (FPCB) and a polarizing layer in display devices often results in bubble formation, which affects the visibility and aesthetics of the display, particularly in the non-display areas, as the thickness of the FPCB causes height differences that lead to bubble generation between the polarizing layer and the touch sensor.
Innovation Solution
A printed layer is strategically disposed between the FPCB and the sensing area or between the display panel and the touch sensor to prevent the visibility of bubbles by either covering or reducing the reflection of light on these areas, ensuring a seamless and bubble-free surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flexible printed circuit board is mounted on the peripheral area of the touch sensor, then electrical connection and signal transmission are achieved, but bubbles are generated due to height differences caused by FPCB thickness
Solution Approach 1:
A printed layer is introduced as an intermediary element between the FPCB and the polarizing layer. This printed layer serves as a mediator that absorbs height differences and prevents direct contact between the FPCB thickness and the polarizing layer, thereby eliminating bubble formation while maintaining electrical connectivity through the FPCB.
Solution Approach 2:
The invention converts the harmful effect of FPCB thickness (which causes height differences and bubbles) into a beneficial outcome. By applying a printed layer that specifically targets the bubble-prone areas, the thickness-induced height differences are transformed into an opportunity to enhance display quality by preventing bubble visibility, thus turning a manufacturing defect into a quality improvement feature.
2Area of stationary object
If the non-display area is minimized to enhance display area, then screen real estate is increased, but adequate mounting space for FPCB is reduced
Solution Approach 1:
The printed layer is applied selectively only in specific regions where bubbles are most likely to form (between the FPCB and polarizing layer), rather than uniformly across the entire display. This localized application allows the FPCB to be mounted in the peripheral area without compromising the overall display area, as the printed layer only occupies minimal space at the interface regions.
3Object-affected harmful factors
If FPCB thickness is reduced to minimize height differences, then bubble generation is reduced, but structural integrity and electrical performance may be compromised
Solution Approach 1:
Rather than reducing the FPCB thickness which would compromise its structural and electrical properties, the invention introduces a printed layer as an intermediary that compensates for the height differences caused by the FPCB thickness. This allows the FPCB to maintain its optimal thickness for structural integrity and electrical performance while the printed layer prevents bubble formation at the interface.
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
The printed layer effectively conceals or minimizes the visibility of bubbles, enhancing the visual clarity and uniformity of the display device by eliminating the height differences caused by the FPCB, thereby maintaining a clear and sharp display area.
Implementation Method 1
A printed layer is strategically disposed between the FPCB and the sensing area or between the display panel and the touch sensor to prevent the visibility of bubbles by either covering or reducing the reflection of light on these areas
Data Source
AI summary
A display device including a display panel having a display area and a non-display area disposed around the display area; a touch sensor disposed on the display panel, the touch sensor comprising a sensing area corresponding to the display area, a peripheral area corresponding to the non-display area, and a pad unit disposed on a part of the peripheral area; a flexible printed circuit board disposed on the touch sensor in the peripheral area and connected to the pad unit; a polarization layer disposed on the touch sensor and a part of the flexible printed circuit board; and a printed layer disposed on at least an area between the flexible printed circuit board and the sensing area.