Sensing apparatus and method based on electromagnetic induction type
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Solution Overview
Problem
Conventional electromagnetic induction (EI) sensing systems require a large number of channels for input and output signals, leading to increased operational complexity and a heavy burden on firmware due to the need for multiple loop coils on the circuit board.
Innovation Solution
A sensing apparatus with a loop unit comprising sub-loops separated by a predetermined distance and an area determination loop unit, which reduces the number of channels required by determining input candidates based on signals from the sensing loop unit and accurately pinpointing the input point using signals from the area determination loop unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple loop coils are arranged on the circuit board to achieve accurate input position detection, then measurement precision is improved, but device complexity increases due to the large number of channels required for input and output signals
Solution Approach 1:
Each loop coil is divided into two sub-loops separated by a predetermined distance. This segmentation allows the system to determine input position by comparing signals from the two sub-loops, thereby reducing the total number of independent channels needed while maintaining detection accuracy through the differential signal comparison approach
2Measurement precision
If many loop coils are used to cover the touchscreen area, then measurement precision is improved, but the number of operations required to process signals increases, placing a huge burden on firmware
Solution Approach 1:
By segmenting each loop into two sub-loops, the system processes fewer independent coil signals while maintaining spatial resolution through the sub-loop differential measurement technique, thereby reducing firmware processing burden
Solution Approach 2:
The two sub-loops within each coil serve multiple functions: they collectively provide area coverage while individually providing position differentiation capability, allowing a single coil structure to perform both coverage and precision detection functions
3Measurement precision
If a large number of channels are assigned for every loop coil, then measurement precision is improved, but ease of operation deteriorates due to increased operational complexity
Solution Approach 1:
The segmentation of loops into sub-loops simplifies the channel assignment scheme by reducing the total number of channels needed, making the system easier to operate while maintaining precision through the sub-loop signal comparison method
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 accurate determination of input positions with fewer channels, reducing operational complexity and firmware burden, while also decreasing the time required for scanning and reducing the number of switches and driving current needed.
Implementation Method 1
an EI type requires a small area to receive an input. For the EI type, a voltage is controlled to be applied to a loop coil arranged on a circuit board to generate an electromagnetic field for propagation to an EI pen
Data Source
AI summary
A sensing apparatus and method are provided for determining an input point of a touch. A sensing loop unit includes at least one loop. Each of the at least one loop includes two sub-loops separated by a predetermined distance. An area determination loop unit determines one of the two sub-loops of each of the at least one loop that corresponds to the input point. A controller determines a plurality of candidates of the input point based on a first input signal from the sensing loop unit, and determines the input point from among the plurality of candidates of the input point based on a second input signal from the area determination loop unit.