Foldable Digitizer Closed-Loop Routing to Reduce FPCB Pin Count
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Solution Overview
Problem
In foldable electronic devices with multiple housings, the connection of digitizers to a controller via connector-to-connector flexible printed circuits boards (C2C FPCBs) results in reduced digitizer performance and increased pin requirements due to the need for multiple conductive wires and signal connections.
Innovation Solution
A conductive line in one digitizer forms a closed loop with another digitizer and connects to a reference line, reducing the need for multiple connections to the controller, thereby minimizing the number of pins required on the C2C FPCB.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple conductive wires are used to connect digitizers to the controller via C2C FPCBs, then the digitizer performance deteriorates due to signal interference, but the pin requirements increase
Solution Approach 1:
The patent merges the reference potential connections of multiple digitizers into a single shared reference line on the C2C FPCB. Instead of providing separate reference wires for each digitizer, the invention combines these connections into one common reference potential path, thereby reducing the total number of pins required while maintaining proper signal reference for all digitizers
Solution Approach 2:
The reference line on the C2C FPCB serves multiple functions simultaneously: it provides the reference potential for all digitizers connected to the FPCB and establishes a common ground path for signal return. This multi-functional design eliminates the need for separate reference connections for each digitizer, reducing pin count while maintaining system reliability
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 enhances digitizer performance by minimizing signal interference and reducing the number of pins on C2C FPCBs, thereby improving the operational efficiency and connectivity of digitizers in foldable electronic devices.
Implementation Method 1
The digitizer may detect a magnetic field signal including a resonance frequency generated from a stylus pen through a digitizer using an electromagnetic resonance (hereinafter referred to as EMR) method
Implementation Method 2
The digitizer may generate a signal for identifying the location of a stylus pen, based on an induced electromotive force generated by the magnetic field generated from the stylus pen
Data Source
Figure 1
Figure 2A~2B
Figure 2C
AI summary
According to various embodiments, an electronic device comprises: a first housing; a second housing rotatably connected to the first housing with respect to a rotation axis; a first digitizer located within the first housing and including a plurality of first conductive lines; a second digitizer located within the second housing and including a plurality of second conductive lines; and a controller located within the first housing, wherein first ends of the plurality of first conductive lines are connected to a plurality of signal output ends of the controller, respectively, and second ends of the plurality of first conductive lines are connected to first ends of the plurality of second conductive lines, respectively, and second ends of the plurality of second conductive lines may be respectively connected to reference lines extending from reference ends of the controller into the second digitizer. Other various embodiments may be possible.