Backlight Printed Circuit Wiring Layer Segmentation for Rework
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Solution Overview
Problem
The existing manufacturing processes for display devices face difficulties in efficiently mounting light sources on printed circuits and performing rework due to defects, leading to challenges in replacing the printed circuit and maintaining manufacturing efficiency.
Innovation Solution
A printed circuit design featuring multiple wiring layers, including a main metal layer, a sub-metal layer, and a bonding metal layer, where the bonding metal layer is partially removed over light sources, allowing for efficient mounting and rework by enabling electrical connection through the sub-metal layer even if the main metal layer is removed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If a light source is mounted on a printed circuit using conventional single-layer wiring, then the mounting process is simple, but rework becomes difficult and requires complete printed circuit replacement
Solution Approach 1:
The wiring layer is divided into multiple segments (main metal layer, sub-metal layer, bonding metal layer) with different functions. The bonding metal layer provides initial bonding, the main metal layer provides primary electrical connection, and the sub-metal layer provides backup connection, enabling segmented functionality that improves rework capability.
Solution Approach 2:
The sub-metal layer is prepared in advance as a backup connection path. When the main metal layer is removed during rework, the sub-metal layer already exists to provide continuous electrical connection, cushioning against the loss of the main connection path and enabling easy rework.
2Ease of repair
If the bonding metal layer is completely removed in the light source mounting area, then rework is easier, but electrical connection reliability deteriorates
Solution Approach 1:
The bonding metal layer is selectively removed only in specific areas where light sources are mounted, while being retained in other areas. This local removal approach provides easy rework at mounting positions while maintaining connection reliability in other regions where the bonding metal layer remains intact.
Solution Approach 2:
The structure changes the presence/absence parameter of the bonding metal layer spatially - it is removed in light source mounting areas to facilitate rework, while retained in other areas to maintain reliability, creating a spatially varying parameter distribution that balances both requirements.
3Ease of repair
If multiple wiring layers are used with partial bonding metal layer removal, then rework capability improves, but manufacturing complexity increases
Solution Approach 1:
The multi-layer wiring structure with selective bonding metal layer removal is established during the initial manufacturing process. This preliminary action creates the rework-friendly structure in advance, so that subsequent light source mounting and potential rework operations become simpler, even though the initial manufacturing is more complex.
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 design facilitates the efficient mounting of light sources on printed circuits and allows for easy rework, improving manufacturing efficiency and reducing the complexity of replacing defective light sources, thereby enhancing the production yield and image quality of display devices.
Implementation Method 1
A portion of the sub-metal layer located in the area overlapping the bonding metal layer in the area overlapping at least one light source of the plurality of light sources may be in an alloy state.
Data Source
AI summary
Embodiments of the present disclosure relate to a printed circuit, a backlight unit, and a display device. The printed circuit on which a light source is mounted can be easily manufactured in a single form, by depositing and arranging a wiring layer on a substrate and mounting the light source on the wiring layer. Further, the printed circuit is arranged so that the wiring layer includes a plurality of bonding metal layers and a plurality of wiring metal layers, and a part of the bonding metal layer positioned between the plurality of wiring metal layers and disposed in an area overlapping a pad portion of the light source is removed. Therefore, even though the main metal layer of the wiring layer is removed during reworking, it is possible to provide the printed circuit capable of electrically connecting to the light source by the sub-metal layer of the wiring layer.