Proximity Sensor Signal Switching for Interference Avoidance

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Solution Overview

Problem

Proximity sensor devices face challenges in effectively distinguishing between background interference and input object coupled interference, which affects their accuracy and usability in electronic systems.

Innovation Solution

The method involves determining a relative ranking of transmitter signals based on background interference and shifting to a different transmitter signal when input object coupled interference exceeds a threshold, using a processing system to select and transmit signals with sensor electrodes, optimizing interference avoidance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a proximity sensor device uses a single transmitter signal, then the device complexity is low, but the measurement precision deteriorates due to inability to distinguish between background interference and input object coupled interference

Engineering Contradiction:
Improvedistinguishing interference typesVSAvoidtransmitter signal management
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the transmitter signals into multiple distinct signals with different waveform characteristics (sine, square, triangular waves at different frequencies). This segmentation allows the system to differentiate between background interference and input object coupled interference by analyzing which signal types are affected, thereby resolving the contradiction between measurement precision and device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the parameters of transmitter signals by using multiple waveform types (sine, square, triangular) and different frequencies. This parameter variation enables the system to identify interference patterns and distinguish between background interference and input object coupled interference, improving measurement precision without excessive complexity increase.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the device transmits multiple transmitter signals with different waveform characteristics, then the measurement precision improves for distinguishing interference types, but the device complexity increases

Engineering Contradiction:
Improveinterference classification accuracyVSAvoidsignal processing system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements periodic transmission of different transmitter signals in a cyclic manner. The processing system periodically switches between sine, square, and triangular wave signals at different frequencies, allowing interference classification to be performed in discrete time intervals. This periodic approach improves measurement precision while managing device complexity by using structured, predictable signal sequences rather than continuous complex processing.

Inventive Principle:
Principle #19Periodic action

3Reliability

If the processing system continuously monitors and shifts between multiple transmitter signals, then the reliability of interference avoidance improves, but the loss of time increases due to signal switching

Engineering Contradiction:
Improveinterference avoidance performanceVSAvoidsignal switching time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-ranking the multiple transmitter signals based on their expected effectiveness for different interference conditions. The processing system maintains a predetermined ranking of signals (e.g., sine wave first, square wave second, triangular wave third) and switches between them based on detected interference patterns. This pre-established ranking reduces the time needed for real-time decision-making, thereby improving reliability without excessive time loss.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by continuously monitoring the received signals and using this information to dynamically select and switch between transmitter signals. The processing system analyzes the characteristics of received signals, compares them against the pre-ranked signal list, and switches to the most appropriate signal for current conditions. This feedback mechanism ensures high reliability of interference avoidance while minimizing time loss through intelligent, adaptive signal selection rather than continuous switching.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS9965104B2Device and method for interference avoidance in an input device
Publication Date: 2018.05.08 SYNAPTICS INC

AI summary

Devices and methods are provided that facilitate improved interference avoidance performance. The devices and methods determine a relative ranking for a plurality of transmitter signals based on a first class of interference for each transmitter signal of the plurality of transmitter signals. The devices and methods transmit a first transmitter signal of the plurality of transmitter signals with a sensor electrode of the plurality of sensor electrodes. The first transmitter signal is selected based on the relative ranking for the plurality of transmitter signals. The devices and methods shift from transmitting the first transmitter signal to transmitting a second transmitter signal of the plurality of transmitter signals with the sensor electrode is based on an amount of a second class of interference in the first transmitter signal. The second transmitter signal is selected based on the relative ranking for the plurality of transmitter signals.