Segmented Loop Coil Position Measurement Device
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Solution Overview
Problem
Existing electromagnetic induction (EI) type touch screens face challenges with high power consumption and increased mounting area and cost due to the need to supply electrical current to all loop coils for position measurement, which is inconvenient for portable devices.
Innovation Solution
A position measurement device utilizing a first sub-loop unit for transmitting and receiving electromagnetic signals and a second sub-loop unit for sensing, where only specific loops are used for transmission and others for reception, reducing power consumption and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrical current is supplied to all loop coils for electromagnetic induction, then position measurement capability is achieved, but power consumption increases
Solution Approach 1:
The loop coils are divided into two distinct groups: transmitting/receiving loops (first sub-loop unit) and receiving loops (second sub-loop unit). Only the first sub-loop unit is supplied with electrical current, while the second sub-loop unit operates passively. This segmentation reduces the number of active loops, thereby decreasing power consumption while maintaining position measurement functionality through the coordinated operation of both groups.
2Reliability
If electrical current is supplied to all loop coils, then electromagnetic field coverage is improved, but mounting area and cost increase
Solution Approach 1:
The loop coil array is segmented into transmitting/receiving loops and receiving loops. The transmitting/receiving loops generate and detect electromagnetic signals, while the receiving loops enhance signal detection capability without requiring active power supply. This segmentation achieves comprehensive electromagnetic field coverage through coordinated operation of both sub-loop units while reducing the number of active components, thereby decreasing mounting area and associated costs.
3Power
If high voltage capability devices are used to apply strong electrical current to all loop coils, then signal intensity is improved, but device complexity and cost increase
Solution Approach 1:
The system segments the loop coil functionality into active transmitting/receiving loops and passive receiving loops. This segmentation allows the use of lower voltage capability devices since only a subset of loops requires high current supply, rather than powering all loops. The passive receiving loops contribute to signal detection without requiring power supply infrastructure, thereby reducing device complexity and cost while maintaining adequate signal intensity for position measurement.
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 approach reduces power consumption by applying current to only necessary loops, decreases the number of required switches, and enhances signal processing efficiency, allowing for precise position measurement with lower voltage capabilities and reduced mounting area.
Implementation Method 1
a loop coil, which is disposed in a circuit board, is applied with a voltage to thereby generate an electromagnetic field, and the electromagnetic field is controlled to be transferred to an EI pen
Implementation Method 2
the EI pen includes a condenser and a loop and emits an electromagnetic field having a predetermined frequency in response to the transferred electromagnetic field
Implementation Method 3
The electromagnetic field emitted by the EI pen is transferred to the loop coil of the circuit board, so the position of where the EI pen approaches the touch screen can be determined
Data Source
AI summary
A position measurement device for measuring a position of a pen is provided. The position measurement device includes a first sub-loop unit that includes at least one loop configured to apply an electrical current or measuring an electromagnetic field change; a second sub-loop unit having at least one loop configured to measure the electromagnetic field change; and a control unit configured to determine at least one loop of the first sub-loop unit as a transmission signal transmitting loop to thereby apply the electrical current to the transmission signal transmitting loop, and measure the position of the pen based on the electromagnetic field change measured by each of the at least one loop of the first sub-loop unit and each of the at least one loop of the second sub-loop unit.