Antenna Switching for SAR Compliance in Tablet Displays
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Solution Overview
Problem
Information processing apparatuses with antennas for wireless communication, such as tablet PCs, face challenges in conforming to radio wave absorption standards when used in tablet mode, as the antenna can be close to the user's body, potentially exceeding specific absorption rate (SAR) limits.
Innovation Solution
The apparatus includes an antenna switching unit that switches the roles of antennas when in tablet mode, ensuring the antenna closer to the user's body functions as a receiving antenna, while the other antenna handles transmission, thereby reducing radio wave absorption by the user's body and maintaining effective wireless communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the antenna is provided in the display unit for wireless communication, then wireless communication functionality is achieved, but the specific absorption rate (SAR) may exceed regulatory standards when the tablet is used in tablet mode
Solution Approach 1:
The patent divides the single antenna system into two separate antennas: a first antenna and a second antenna. This segmentation allows the system to switch between different antenna configurations based on usage mode, enabling compliance with SAR regulations in tablet mode while maintaining wireless communication functionality.
Solution Approach 2:
The patent implements dynamic antenna role assignment where the roles of transmitting and receiving antennas are switched based on the detected usage mode. In notebook mode, the first antenna transmits and the second receives; in tablet mode, this is reversed. This dynamic adaptation allows the system to maintain wireless functionality while complying with SAR regulations.
2Volume of moving object
If the antenna is located close to the user's body in tablet mode, then the device maintains compact form factor, but radio wave absorption by the user's body increases
Solution Approach 1:
The patent inverts the typical antenna role assignment based on usage mode. Instead of keeping the same transmitting antenna regardless of mode, the system reverses which antenna transmits and which receives when switching from notebook mode to tablet mode. This inversion ensures that when the tablet is held close to the body in tablet mode, the transmitting antenna is positioned to minimize exposure to the user's body.
3Object-affected harmful factors
If the antenna roles are switched based on usage mode, then SAR compliance is achieved, but antenna switching complexity increases
Solution Approach 1:
The patent implements a self-service mechanism where the usage mode detection and antenna role switching are automatically performed by the system without requiring manual user intervention. The system detects whether it is in notebook mode or tablet mode and automatically assigns antenna roles accordingly, simplifying the user experience while maintaining SAR compliance.
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 solution allows for compliant wireless communication by minimizing radio wave absorption and preventing a decrease in radiation efficiency, ensuring the apparatus meets regulatory standards and maintains effective communication.
Implementation Method 1
an antenna for radiating radio waves
Implementation Method 2
a first antenna which serves as a transmitting antenna and a second antenna which serves as a receiving antenna
Data Source
AI summary
According to one embodiment, an information processing apparatus includes a display unit. A display portion is provided in the display unit. Antennas are provided in the display unit. The antennas include a first antenna which serves as a transmitting antenna and a second antenna which serves as a receiving antenna. An antenna switching unit makes, when the display unit is used in a state where the first antenna is located in a side of the display unit which side is closest to a user, the first antenna serve as the receiving antenna, and the second antenna serve as the transmitting antenna.