摘要 |
The microwaviness (i.e., surface waviness for wavelengths on the order of the length of the transducing head) of a recording disk surface is measured during manufacture as a quality control process. Preferably, the disk is measured using an actuator-mounted thermal sensor, comprising an electrical resistance element driven with a constant current. At small distances, the disk surface acts as a heat sink and variation in this distance will be detected as a change in resistance of the sensor. Preferably the sensor is initially used to characterize the gross waviness of the surface, and the actuator then follows this gross waviness to measure surface variations in the microwaviness range.
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