Coordinate Input Device Shield Sheet Wireless Interference
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Solution Overview
Problem
The downsizing of coordinate input devices makes it difficult to arrange wireless communication circuits at a sufficient distance from the coordinate sensor, leading to interference and noise issues, and there is a need for a compact integration of wireless communication circuits and transmission antennas to simplify manufacturing and reduce costs.
Innovation Solution
A coordinate input device configuration that includes a sensor, a top plate, a shield sheet, a coordinate data formation circuit, and a controller, where the shield sheet with electrical conductivity and magnetic properties covers the sensor to shield it from radio waves and magnetic fluxes, allowing the controller and transmission antenna to be positioned close to the sensor without interfering with coordinate detection, and the transmission antenna is arranged outside the shield sheet to prevent interference with the electronic pen and sensor signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wireless communication circuit is arranged at a sufficient distance from the coordinate sensor to avoid interference, then the coordinate detection reliability is improved, but the device size increases and manufacturing complexity increases
Solution Approach 1:
The device is divided into two distinct regions by the shield sheet: a first region containing the coordinate sensor free from wireless communication interference, and a second region containing the wireless communication circuit. This spatial segmentation allows both components to be placed close together while maintaining functional independence and preventing mutual interference.
Solution Approach 2:
The shield sheet is selectively positioned between the coordinate sensor and wireless communication circuit to create a localized electromagnetic shield. This allows the wireless communication circuit to operate at high power for good transmission range while the sensor region maintains electromagnetic purity for accurate coordinate detection, achieving both reliability and compactness.
2Measurement precision
If the wireless communication circuit is arranged at a sufficient distance from the coordinate sensor to avoid noise interference, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The shield sheet acts as an intermediary element between the coordinate sensor and wireless communication circuit. It selectively blocks electromagnetic noise from the wireless circuit while allowing the compact integration of both components, thereby maintaining measurement precision without increasing device complexity.
3Ease of manufacture
If the wireless communication circuit and transmission antenna are integrated on a compact substrate, then the ease of manufacture is improved, but the harmful factors increase due to proximity to the sensor
Solution Approach 1:
The harmful electromagnetic effects are extracted and contained within the second region by the shield sheet. This allows the wireless communication circuit and transmission antenna to be integrated on a compact substrate for ease of manufacture, while the shield prevents these harmful factors from affecting the coordinate sensor in the first region.
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 enables wireless transmission of coordinate data without affecting the coordinate detection by the sensor, allows for the downsizing of the device, and simplifies the manufacturing process by integrating the wireless communication circuit and transmission antenna on a compact substrate, reducing noise interference and enabling efficient data transmission.
Implementation Method 1
The shield sheet has electrical conductivity and magnetic properties, and is provided to cover a whole of a surface of the sensor opposite to the input surface of the sensor
Implementation Method 2
The shield sheet has electrical conductivity and magnetic properties, and is provided to cover a whole of a surface of the sensor opposite to the input surface of the sensor
Implementation Method 3
A coordinate input device including a coordinate sensor of an electromagnetic induction type or a capacitive coupling type
Implementation Method 4
performs control to hold the coordinate data formed by the coordinate data formation circuit and to wirelessly transmit the coordinate data to an external device
Data Source
AI summary
A coordinate input device including a coordinate sensor and a wireless communication circuit that wirelessly transmits coordinate data, etc. to an external electronic device is realized without affecting coordinate detection by the coordinate sensor and without impeding downsizing of the coordinate input device. A shield sheet (1C) is provided to cover the whole of a surface (back surface) of a sensor (1B) opposite to a sensor input surface (front surface) facing an electronic pen. A controller (200) that controls transmission of the coordinate data detected by the sensor (1B) to the external electronic device is disposed facing the sensor (1B) with the shield sheet (1C) disposed between the sensor and the controller, and a transmission antenna connected with the controller (200) is arranged outside a region covered with the shield sheet (1C).