Bent Tail Flexible Circuit Board for Display Touch Sensor Dead Space Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Flat panel displays face challenges in minimizing dead space occupied by flexible printed circuit boards for touch sensors, which limits the compactness and robustness of the display device structure.
Innovation Solution
The design incorporates a second flexible printed circuit board with a bent tail portion that is more flexible and thinner than the rest, connected via a zero insertion force (ZIF) connector and anisotropic conductive film, allowing for reduced protrusion and overlap with the first flexible printed circuit board, thereby minimizing dead space and enabling a more compact structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flexible printed circuit boards are used for touch sensor connectivity, then electrical connection is achieved, but dead space increases and compactness deteriorates
Solution Approach 1:
The second flexible printed circuit board is positioned and configured to nest within or alongside the first flexible printed circuit board structure. The tail portion of the second FPCB is routed to overlap with the body portion, allowing the second FPCB to connect to the touch sensing layer while sharing space with the first FPCB that connects to the display layer, thereby reducing overall dead space occupation.
Solution Approach 2:
The second flexible printed circuit board incorporates a bent tail portion that extends in a different spatial dimension or direction compared to the first FPCB. This dimensional variation allows the second FPCB to achieve electrical connection to the touch sensing layer while minimizing its projection area and reducing overlap with other components, thus reducing dead space.
2Area of stationary object
If flexible printed circuit boards are made thinner and more flexible, then compactness improves, but structural strength deteriorates
Solution Approach 1:
The second flexible printed circuit board features a differentiated structure where the tail portion is made thinner and more flexible than the body portion. The body part maintains sufficient thickness and rigidity for structural strength and electrical connection, while the tail part is locally optimized to be thinner and more flexible to reduce dead space and improve compactness. This local quality variation resolves the contradiction between compactness and structural strength.
Data Source
AI summary
A display device including a touch sensor is disclosed. In one aspect, the display device includes a lower substrate and a display layer formed over the lower substrate. An upper substrate is formed over the display layer and a touch sensing layer is formed over the upper substrate. The display device also includes a first flexible printed circuit board electrically connected to the display layer and attached to a surface of the lower substrate and a second flexible printed circuit board electrically connected to the touch sensing layer and attached to the surface of the lower substrate. The second flexible printed circuit board includes a body having a first end connected to the touch sensing layer and a tail extending from a second end. The tail includes a connection portion electrically connected to the first flexible printed circuit board and at least a portion of the tail is bent.