Position Detection Device With Variable Magnetic Field Angle
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Solution Overview
Problem
Position detection devices using magnetic sensors have low sensitivity due to a low ratio of composite vector angle variation to lens position variation, limiting their effectiveness in precise position detection.
Innovation Solution
A position detection device is designed with a first and second magnetic field generation unit, where the relative position of the second magnetic field generation unit is variable, creating a composite magnetic field with a relative angle greater than 90° and less than 180°, enhancing sensitivity by varying the strength of the second magnetic field and thus the detection signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic sensor detects a composite vector generated by interaction between a first magnetic field and a second magnetic field, then the lens position can be detected, but the sensitivity for position detection is low due to low ratio of composite vector angle variation to lens position variation
Solution Approach 1:
The patent changes the geometric parameter (relative angle) between the first and second magnetic field generation units from the conventional 90° to a range of 105° to 165°. This parameter change optimizes the relationship between lens position variation and composite magnetic field direction variation, thereby improving position detection sensitivity without requiring additional sensors or complex structures.
2Measurement precision
If the relative position of the second magnetic field generation unit is variable to enhance sensitivity, then the detection signal variation increases, but the device complexity increases
Solution Approach 1:
The patent applies local quality by making only the second magnetic field generation unit's relative position variable, while keeping the first magnetic field generation unit fixed. This localized adjustment optimizes sensitivity without requiring the entire system to be reconfigurable, thereby limiting the increase in device complexity to a specific component rather than the whole system.
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
The device achieves higher sensitivity for position detection, as demonstrated by increased variation in the detection signal with respect to the relative position, improving the accuracy of lens position detection in camera modules.
Implementation Method 1
a first magnetic field generation unit for generating a first magnetic field
Implementation Method 2
a second magnetic field generation unit for generating a second magnetic field, the second magnetic field generation unit being provided such that its relative position with respect to the first magnetic field generation unit is variable
Implementation Method 3
a magnetic sensor for detecting a magnetic field to be detected at a predetermined detection position and generating a detection signal corresponding to the direction of the magnetic field detected
Data Source
AI summary
A position detection device includes a first magnetic field generation unit for generating a first magnetic field, a second magnetic field generation unit for generating a second magnetic field, and a magnetic sensor. The relative position of the second magnetic field generation unit with respect to the first magnetic field generation unit is variable. The magnetic sensor detects a composite magnetic field of the first and second magnetic fields, and generates a detection signal corresponding to the direction of the detected magnetic field. Varying the relative position of the second magnetic field generation unit with respect to the first magnetic field generation unit varies the strength of the second magnetic field at the detection position. At the detection position, a relative angle formed by the direction of the second magnetic field with the direction of the first magnetic field is greater than 90° and smaller than 180°.