Slider Thermal Sensor for Laser Power Monitoring in HAMR
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Solution Overview
Problem
In heat-assisted magnetic recording, there is a need to monitor and control laser power effectively once the recording head is assembled in a drive, as existing methods lack a reliable means to measure or adjust optical power during operation.
Innovation Solution
A thermal sensing element is integrated into the slider of a heat-assisted magnetic recording system, which is heated by a portion of the laser light and changes its resistance or voltage, allowing a controller to adjust the laser power based on these changes, thereby compensating for aging or thermal effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a thermal sensor is integrated into the slider to monitor laser power, then laser power control precision is improved, but device complexity increases
Solution Approach 1:
The thermal sensor is integrated directly into the slider structure, merging the sensing function with the existing mechanical component. This combines the laser heating function and temperature sensing function into a single unified structure, enabling laser power monitoring without adding separate external sensing devices.
Solution Approach 2:
The slider serves multiple functions: it acts as both the mechanical carrier for the recording head and as the thermal sensor for laser power monitoring. The thermal sensor element within the slider detects temperature changes caused by laser heating, providing feedback for power control while the slider itself performs its traditional mechanical functions.
2Reliability
If a thermal sensor is mounted to be heated by laser light, then laser power monitoring capability is improved, but the sensor must withstand thermal conditions
Solution Approach 1:
The thermal sensor acts as an intermediary element that converts optical energy (laser light) into thermal energy and then into electrical signals (resistance or voltage changes). The sensor material absorbs a portion of the laser light and converts it to heat, which then produces measurable electrical properties for monitoring.
Solution Approach 2:
The sensor operates by detecting changes in its electrical parameters (resistance or voltage) in response to temperature changes caused by laser heating. The thermal sensor material exhibits predictable parameter changes with temperature, allowing the system to monitor laser power by measuring these parameter variations.
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 enables precise monitoring and control of laser power, optimizing recording performance by adjusting for changes in laser power due to aging or thermal effects, thereby improving bit error rate, track width, and channel quality.
Implementation Method 1
the sensor being mounted to be heated by a portion of light emitted by the light source
Implementation Method 2
a sensor having a resistance or voltage that varies with the temperature of the sensor
Data Source
AI summary
An apparatus includes a light source, a slider including a sensor having a resistance or voltage that varies with the temperature of the sensor, the sensor being mounted to be heated by a portion of light emitted by the light source, and a controller controlling the light source power in response to the resistance or voltage of the sensor.