Electromagnetic Induction Sensor Edge Detection with Variable Loop Coil Width
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Solution Overview
Problem
Electromagnetic induction position input devices face challenges in accurately detecting the position of a pen-shaped position indicator near the edge portions of the sensor, leading to erroneous detection due to the use of the two-point detection method, which results in a disabled area that extends into the display area when trying to downsize the bezel without increasing costs.
Innovation Solution
The electromagnetic induction position detection sensor is designed with N-turn loop coils where each coil turn has long side portions separated by a predetermined width and arranged at specific intervals, with at least one turn's width larger than the others near the edge, optimizing signal distributions to prevent erroneous detection and reduce the disabled area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the two-point detection method is used to detect position near edge portions, then the detection area can be enlarged, but erroneous detection occurs due to insufficient reception signals
Solution Approach 1:
The patent applies local quality by making the Mth loop coil from the edge portion have different characteristics (larger width) compared to other loop coils. This localized modification allows the edge portion to generate sufficient reception signals for accurate two-point detection, while other areas maintain their original design. The unequal width configuration specifically addresses the signal insufficiency problem at edge portions without affecting the overall sensor structure.
Solution Approach 2:
The patent changes the physical parameter of the loop coil width at the edge portion. By making the Mth loop coil wider than the predetermined width, the reception signal level is enhanced in the edge area. This parameter change allows the two-point detection method to be applied successfully near edges, expanding the detection area while maintaining measurement precision through improved signal quality.
2Area of stationary object
If the bezel width is reduced to downsize the device, then the detection area can be enlarged, but the disabled area extends into the display area
Solution Approach 1:
The patent applies local quality by modifying only the Mth loop coil from the edge portion to have a larger width, while other loop coils maintain their standard dimensions. This localized adjustment creates reliable position detection capability in the edge region without requiring an increased bezel width, thus preventing the disabled area from extending into the display area while maintaining detection reliability.
3Ease of manufacture
If uniform width loop coils are used, then the manufacturing process is simplified, but erroneous detection occurs at edge portions
Solution Approach 1:
The patent applies local quality by making the Mth loop coil from the edge portion have a larger width than other loop coils. This localized modification improves reception signal levels specifically at edge portions where signal insufficiency causes erroneous detection, while maintaining uniform width in other areas for manufacturing simplicity. The unequal width configuration is applied only where needed to correct the edge detection problem.
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 effectively eliminates erroneous detection and enlarges the detection area without increasing costs, allowing for a slim border and reduced bezel width, while maintaining accurate position detection.
Implementation Method 1
one loop coil is selected in a predetermined sequence from among the plurality of loop coils arranged in the position detection sensor area, after which a transmission signal is transmitted from the selected loop coil to the pen-shaped position indicator, thus allowing the capacitor of the pen-shaped position indicator to be charged
Implementation Method 2
The position detection sensor includes X- and Y-axis direction loop coil groups that overlap one another... a transmission signal is transmitted from the selected loop coil to the pen-shaped position indicator... receiving a signal from the resonance circuit of the pen-shaped position indicator
Data Source
AI summary
An electromagnetic induction position detection sensor includes a plurality of loop coils, each being an N-turn loop coil formed by winding a conductor N times (N is an integer equal to or greater than 2), and each coil turn having long side portions that are separated by a predetermined width and that are parallel to each other. The loop coils are arranged at predetermined intervals in a predetermined direction intersecting the long side portions of the loop coils. The width of at least one of the N turns of the Mth loop coil from the edge portion of the sensor in the predetermined direction (M is an integer equal to or greater than 2) is larger than the predetermined width, with the long side portion of this turn of the Mth loop coil arranged more outward than the long side portions of the other turns of the Mth loop coil.