Stacked Pad Configuration for Narrow Bezel Display Devices
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Solution Overview
Problem
Conventional display devices have a significant non-display area that limits their ability to achieve a narrow bezel design, which is essential for reducing the overall size and improving aesthetics.
Innovation Solution
The display device employs a stacked configuration of signal and dummy pads on the sides of the display substrate, along with an anisotropic conductive film to bond the substrates and circuit film, reducing the non-display area and enhancing durability by stabilizing the bonding force between the substrates and the circuit film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional pad configurations are used, then the display device can be manufactured with standard bezel width, but the non-display area becomes large, limiting narrow bezel design
Solution Approach 1:
The patent applies dimensionality change by arranging pads in a stacked configuration along the side surface of the substrate rather than spreading them out in the planar non-display area. This transitions the pad layout from a two-dimensional planar arrangement to a three-dimensional stacked arrangement, effectively reducing the occupied area in the non-display region while maintaining all necessary electrical connections.
2Area of stationary object
If the non-display area is reduced to achieve narrow bezel, then the bezel width decreases, but the bonding stability between substrates and circuit film may be compromised
Solution Approach 1:
The patent segments the bonding function by introducing dummy pads specifically dedicated to bonding purposes, separate from the signal transmission pads. This segmentation allows the circuit film to be stably bonded to the substrate through multiple dummy pad locations distributed along the side surface, ensuring bonding reliability even when the overall non-display area is minimized.
Solution Approach 2:
The patent uses an anisotropic conductive film as an intermediary material between the circuit film and the substrate pads (both signal and dummy pads). This intermediary enables electrical connection and mechanical bonding while accommodating thermal expansion differences and ensuring stable attachment in the reduced bezel configuration.
3Length of stationary object
If pads are arranged in stacked configuration, then the bezel width is reduced, but the electrical connection complexity increases
Solution Approach 1:
The patent applies universality by designing the anisotropic conductive film to perform multiple functions simultaneously: it provides electrical connection between signal pads, enables mechanical bonding through dummy pads, and accommodates thermal expansion. This multi-functionality simplifies the overall structure despite the stacked pad arrangement, as a single material system handles multiple requirements.
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 allows for a display device with a narrower bezel and improved durability, effectively minimizing the non-display area while maintaining stable electrical connections and structural integrity.
Implementation Method 1
coupling not only substrate signal pads and the circuit signal pads CSP, but also the circuit dummy pads and the substrate dummy pads, e.g., using an anisotropic conductive film, the first and second substrates and the circuit film can be stably bonded together
Data Source
AI summary
A display device includes: a first substrate having a top surface and a first side surface extending from the top surface; a second substrate facing the first substrate and having a second side surface aligned with the first side surface; substrate signal pads disposed on the first side surface; substrate dummy pads disposed on the second side surface; a circuit film facing the first and second side surfaces; circuit dummy pads disposed on the circuit film and electrically connected to the substrate dummy pads; and circuit signal pads disposed on the circuit film and electrically connected to the substrate signal pads.