Thermally Responsive Sensor Contact Detection
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Solution Overview
Problem
Current data storage devices rely on horizontal displacement measurements to detect contact events between a transducer and a rotating data storage medium, which is reactive and less precise, especially at higher track densities, leading to increased burnishing and deleterious effects.
Innovation Solution
A transducer system with a writer, reader, heater, and thermally responsive sensor, where a control circuit applies power to the heater and supplies a bias current to the sensor to detect contact events based on root mean square (RMS) voltage thresholds, enabling in-situ vertical displacement detection and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If horizontal displacement measurements are used to detect contact events, then the detection method is simple to implement, but the measurement precision is insufficient especially at higher track densities
Solution Approach 1:
The patent replaces the mechanical measurement system (horizontal displacement sensors) with a thermal sensing system. A thermally responsive sensor detects contact events by measuring temperature changes caused by friction when the transducer contacts the medium, substituting mechanical measurement with thermal measurement to achieve higher precision.
Solution Approach 2:
The patent introduces temperature as an intermediary parameter to detect contact events. Instead of directly measuring horizontal displacement or contact force, the system uses temperature change as an intermediate indicator that correlates with contact events, enabling more precise detection through thermal effects.
2Object-affected harmful factors
If reactive contact detection is used, then the system structure is simple, but burnishing and deleterious effects increase
Solution Approach 1:
The patent implements a feedback mechanism where the thermally responsive sensor continuously monitors temperature changes and provides real-time feedback about contact events. This feedback loop enables the control system to respond immediately to contact conditions, allowing proactive adjustment of transducer position or operating parameters to prevent burnishing before it occurs.
Solution Approach 2:
The system performs preliminary detection of contact conditions through thermal sensing before significant burnishing can occur. By detecting early signs of contact through temperature changes, the system can take preventive action before the harmful effects of burnishing accumulate, transitioning from reactive to proactive protection.
3Stability of the object's composition
If heater power is increased to maintain fly height, then fly height stability improves, but energy consumption increases
Solution Approach 1:
The patent implements dynamic control of heater power based on real-time thermal sensor feedback. Instead of applying constant high power to maintain fly height, the system dynamically adjusts heater power levels according to actual contact conditions detected by the thermal sensor, reducing energy consumption during normal operation while maintaining stability when needed.
Solution Approach 2:
The system changes the operating parameter (heater power) based on detected conditions. By monitoring temperature changes and correlating them with contact events, the system adjusts heater power dynamically, using higher power only when fly height stability is compromised and lower power when conditions are stable, thereby optimizing energy consumption.
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 allows for direct detection of vertical contact events, reducing burnishing and increasing system reliability by stabilizing fly height and reducing calibration time, while maintaining accurate contact detection across various operational conditions.
Implementation Method 1
the sensor output signal may be attributed to contact events between the transducer and the medium
Implementation Method 2
a thermally responsive sensor... measuring a root mean square (RMS) voltage VRMS of the thermally responsive sensor
Data Source
AI summary
A method for detecting a contact event between a transducer and a recording medium is disclosed. The method includes positioning a transducer with respect to a recording medium, where the transducer includes a writer, a reader, a heater, and a thermally responsive sensor. The method further includes applying power to the heater to establish a fly height of the transducer; supplying a bias current through the thermally responsive sensor to generate a bias signal; measuring a root mean square (RMS) voltage VRMS of the thermally responsive sensor based on the bias signal; determining a threshold voltage VT; and detecting a contact event between the transducer and the medium based on VRMS being greater than VT.