Flexible Circuit Board Alignment for Narrow Display Frames
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Solution Overview
Problem
Existing display devices, particularly wearable devices, face limitations in narrowing the lower frame due to the minimum recognizable distance constraints of flexible circuit board bonding machines, which restrict the alignment of marks and hinder the achievement of a narrow frame design.
Innovation Solution
The display device incorporates a first substrate with a step region and alignment marks, and a flexible circuit board with corresponding alignment marks, allowing for precise alignment and bonding without overlapping projections, enabling the flexible circuit board to be positioned with a preset coordinate difference, thus overcoming the distance limitations and allowing for a narrower frame design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the distance between alignment marks is reduced to narrow the frame, then the frame width is reduced, but the bonding machine cannot recognize the alignment marks due to minimum recognizable distance constraints
Solution Approach 1:
The patent introduces a coordinate difference (dx, dy) between the first alignment marks on the substrate and second alignment marks on the flexible circuit board. This dimensional offset allows the alignment marks to be positioned such that they do not overlap, enabling the bonding machine to recognize both sets of marks simultaneously while maintaining narrow frame dimensions. The coordinate transformation (X2-X1=dx, Y2-Y1=dy) creates a non-overlapping spatial relationship that resolves the recognition constraint.
Solution Approach 2:
The alignment system is divided into two separate sets of alignment marks: first alignment marks on the substrate and second alignment marks on the flexible circuit board. These segmented marks are positioned at different locations with a preset coordinate difference, allowing the bonding machine to recognize them independently without the overlap constraint that would exist if a single set of marks were used.
2Area of stationary object
If the alignment marks are positioned close together to reduce frame size, then the frame is narrower, but the orthographic projections of the alignment marks overlap, preventing proper recognition
Solution Approach 1:
By introducing a preset coordinate difference (dx, dy) between the two sets of alignment marks, the patent creates a spatial separation in the projection plane. This dimensional offset ensures that the orthographic projections of the first alignment marks and second alignment marks do not overlap, making both sets detectable by the bonding machine's imaging system while maintaining a compact bonding region.
3Length of stationary object
If traditional alignment mark positioning is used, then the process is simple, but the lower step region cannot be narrowed in the lateral direction
Solution Approach 1:
The patent pre-establishes a coordinate difference (dx, dy) between the first and second alignment marks during the design and fabrication stages. This preliminary positioning allows the bonding machine to automatically recognize both sets of marks without requiring complex real-time adjustment mechanisms, thus narrowing the lower step region while keeping the alignment process relatively simple.
Data Source
AI summary
Display device and fabrication method are provided. The display device includes a first substrate and a flexible circuit board. The first substrate includes a step region, first alignment marks, and a base substrate. The step region includes a bonding region and the bonding region includes a plurality of first pads arranged in at least one row along a first direction. The flexible circuit board is bonded in the bonding region and includes second alignment marks. Orthographic projections of the first alignment marks on a plane of the base substrate do not overlap an orthographic projection of the flexible circuit board on the plane of the base substrate, and do not overlap orthographic projections of the second alignment marks on the plane of the base substrate.