Proximity Sensor Fault Detection for Antenna Power Limiting

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Solution Overview

Problem

Mobile terminals' radiation levels, monitored by proximity sensors like SAR sensors, can exceed safe limits when these sensors fail to detect human proximity, leading to potential harm to users due to unadjusted antenna transmitting power.

Innovation Solution

A method and apparatus for detecting the state of a proximity sensor by sending predetermined instructions to determine abnormal conditions, such as capacitance value deviations or communication failures, and adjusting antenna transmitting power to maintain low power levels when the sensor is abnormal, ensuring user safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the proximity sensor is not monitored for abnormality, then the terminal can operate with normal antenna transmitting power, but radiation exposure exceeds safe limits when the sensor fails

Engineering Contradiction:
Improveradiation exposureVSAvoidsensor functionality
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The system performs preliminary detection by sending a detection instruction to the proximity sensor before normal operation proceeds. The detection unit checks whether the sensor is functioning properly by analyzing its response. If the sensor is found to be abnormal before radiation exposure occurs, the system proactively limits antenna transmitting power to prevent harmful radiation, thus applying preliminary action to avoid the harmful effect.

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If the antenna transmitting power is continuously monitored and adjusted, then radiation safety is improved, but device complexity increases due to additional detection and control mechanisms

Engineering Contradiction:
Improveradiation safetyVSAvoiddetection and control system
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The detection unit leverages the existing communication interface between the processor and proximity sensor, using the same instruction sending and response receiving mechanisms already present in the terminal. By making the existing communication system multi-functional (serving both normal control and safety detection purposes), the patent avoids adding separate dedicated detection hardware, thus reducing the increase in device complexity while still achieving radiation safety monitoring.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If the proximity sensor detection function is added, then radiation safety is improved, but manufacturing cost increases due to additional components

Engineering Contradiction:
Improveradiation safetyVSAvoidmanufacturing cost
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The proximity sensor performs self-detection by responding to detection instructions sent by the processor. The sensor's own communication capability is utilized to report its operational status back to the processor. This self-service approach eliminates the need for separate external detection sensors or additional hardware components, thereby avoiding increased manufacturing costs while still achieving the goal of radiation safety through sensor functionality monitoring.

Inventive Principle:
Principle #25Self-service

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 radiation exposure by maintaining antenna power at the lowest level when the proximity sensor is not functioning correctly, ensuring both safe operation and user safety while allowing for real-time power adjustments when the sensor is operational.

Implementation Method 1

the predetermined instruction comprises a capacitance value detection instruction for enabling the proximity sensor to detect a background capacitance value of a background circuit

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3945680A1Method and apparatus for detecting state of proximity sensor, terminal and non-transitory computer-readable storage medium
Publication Date: 2022.02.02 BEIJING XIAOMI MOBILE SOFTWARE CO LTD
  • EP3945680A1 patent drawingFigure 1~2
  • EP3945680A1 patent drawingFigure 3~4
  • EP3945680A1 patent drawingFigure 5~7

AI summary

A method for detecting the state of the proximity sensor, applied to a terminal including the proximity sensor and an antenna, includes: sending a predetermined instruction to the proximity sensor; determining whether the proximity sensor is abnormal based on a feedback result of the proximity sensor to the predetermined instruction; and maintaining the antenna transmitting power at a low power if the proximity sensor is abnormal. Through the feedback of the proximity sensor to the request to obtain the capacitance value, it is determined whether the proximity sensor can work normally, and in a case that the proximity sensor cannot work normally, the antenna transmitting power is reduced to avoid the continuous higher antenna transmitting power due to the inability of the proximity sensor to work normally, which reduces the radiation to the human body.