Optical Module Magnet Temperature Compensation
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Solution Overview
Problem
The accuracy of deflection angle measurement in optical modules, particularly in in-vehicle distance measurement devices, is compromised due to temperature changes affecting the magnetic flux density of the magnet, leading to inaccurate data acquisition.
Innovation Solution
An optical module design that includes a support thermally connected to the magnet, featuring a temperature monitoring element to accurately reflect the magnet's temperature, allowing for precise consideration of magnetic flux density changes, along with drive coils and electromotive force monitoring coils to determine the mirror's deflection angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the temperature monitoring element is provided to the movable part together with the drive coil, then the temperature can be monitored, but the temperature monitoring element is affected by heat generated from the drive coil and the space between the movable part and magnet serves as a thermal resistor, causing inaccurate temperature measurement of the magnet
Solution Approach 1:
The support structure serves as a thermal intermediary, conducting heat from the magnet to the temperature monitoring element. By positioning the temperature monitoring element on the support rather than directly on the movable part, the support acts as a thermal bridge that bypasses the thermal resistance of the air gap between the movable part and magnet, enabling accurate temperature measurement of the magnet while isolating the sensor from direct heat interference of the drive coil.
Solution Approach 2:
The system is segmented into distinct thermal zones: the magnet generates magnetic field and heat, the support structure serves as a thermal conduction path, and the temperature monitoring element is positioned on the support to measure magnet temperature. This segmentation separates the temperature monitoring function from the electromagnetic actuation function, allowing independent optimization of each subsystem's thermal characteristics.
2Adaptability or versatility
If the optical module is applied to an in-vehicle distance measurement device, then the device can be used in practical applications, but the operating environment temperature changes significantly cause the magnet temperature to change, leading to inaccurate deflection angle information
Solution Approach 1:
The temperature monitoring element provides continuous feedback on the magnet temperature to the control system. Based on this temperature information, the control system adjusts the drive coil current to compensate for changes in magnetic flux density. This feedback mechanism enables the optical module to maintain accurate deflection angle control across varying operating temperatures, making it suitable for in-vehicle applications where temperature fluctuations are significant.
Solution Approach 2:
The system dynamically changes the drive parameters (coil current) based on the measured magnet temperature. As temperature changes affect the magnetic flux density, the control system adjusts the electrical parameters of the drive coil to maintain the desired mechanical output (deflection angle). This parameter adaptation allows the device to function accurately across the wide temperature range encountered in automotive environments.
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 design enables accurate and reliable acquisition of the mirror's deflection angle, even in varying temperature environments, enhancing the precision of distance measurements in in-vehicle applications.
Implementation Method 1
a magnet that generates a magnetic field acting on the drive coil
Implementation Method 2
The support is thermally connected to the magnet
Implementation Method 3
an electromotive force monitoring coil provided to the movable part... an electromotive force is generated on the electromotive force monitoring coil
Data Source
AI summary
An optical module includes a support, a movable part supported by the support so as to be swingable about an axis, a mirror provided to the movable part, a drive coil provided to the movable part, a temperature monitoring element provided to the support, and a magnet that generates a magnetic field acting on the drive coil. The support is thermally connected to the magnet.