Tape head with thermal tape-head distance sensor
View Patent ↗Tape head with thermal tape-head distance sensor to reduce the distance between the tape and the head to allow an increase in areal density. A tape head designed for reading and/or writing to a tape, including: a tape bearing surface shaped to form an air bearing when moving the tape with respect to the tape bearing surface; a thermal tape-head distance sensor circuit adapted to sense heat dissipated at the level of the tape bearing surface by the tape and thereby sense a distance between the tape bearing surface and the tape; and tape-head distance control means connected to the thermal tape-head distance sensor circuit to receive a signal provided by the tape-head distance sensor circuit and configured to alter the distance according to a signal received from the tape-head distance sensor circuit. This invention is further directed to a method of tape-head distance control for the above tape head.
1. A tape head for reading and/or writing to a tape, comprising:
a thermal tape-head distance sensor circuit configured to sense a distance between a tape bearing surface and the tape based on heat dissipated at the tape bearing surface; and
a tape-head distance control means configured to alter the distance.
2. The tape head according to claim 1 , wherein the tape-head distance control means is configured to keep the distance substantially constant.
3. The tape head according to claim 1 , wherein the tape-head distance control means comprises a closed-loop feedback control circuit configured to provide closed-loop feedback control of the distance according to the signal received from the tape-head distance sensor circuit.
4. The tape head according to claim 1 , wherein the tape-head distance control means comprises a plurality of electrostatic attractors coupled in the control means to alter the distance according to a signal received from the tape-head distance sensor circuit.
5. The tape head according to claim 1 , wherein the thermal tape-head distance sensor circuit comprises:
a heater element arranged at the tape bearing surface such as to be in thermal communication with the tape in operation; and
a heating circuit connected to the heater element, such as to be able to provide power to and heat the heater element.
6. The tape head according to claim 5 , wherein the thermal tape-head distance sensor circuit further comprises a temperature measurement circuit coupled in the thermal tape-head distance sensor circuit to sense the temperature of the heater element.
7. The tape head according to claim 6 , wherein the temperature measurement circuit comprises an electrical resistance measurement circuit connected to the heater element to sense its resistance.
8. The tape head according to claim 7 , wherein the temperature measurement circuit comprises:
the electrical resistance measurement circuit; and
a non-linear resistive electronic component, wherein the electrical resistance measurement circuit is connected to the non-linear resistive electronic component to sense the temperature of the heater element.
9. The tape head according to claim 7 , wherein the temperature measurement circuit comprises the electrical resistance measurement circuit, wherein the electrical resistance measurement circuit comprises:
a constant current source and a voltage meter, whereby the signal provided by the tape-head distance sensor circuit depends on changes in a voltage measured by the voltage meter; or
a constant voltage source and a current meter, whereby the signal provided by the tape-head distance sensor circuit depends on changes in a current measured by the current meter.
10. The tape head according to claim 1 , wherein the thermal tape-head distance sensor circuit further comprises at least one reference temperature sensor, wherein the at least one reference temperature sensor is connected in the sensor circuit to provide a signal corrected according to a reference signal provided by the at least one reference temperature sensor.
11. A method of tape-head distance control for a tape head, the method comprising:
sensing via a thermal tape-head distance sensor circuit a distance between a tape bearing surface and a tape based on heat dissipated at the tape bearing surface; and
altering said distance between the tape bearing surface and the tape based on a signal received from the tape-head distance sensor.
12. The method according to claim 11 , further comprising circulating the tape across the tape head to form an air bearing between the tape and the tape bearing surface.
13. The method according to claim 11 , further comprising generating a signal at the tape-head distance sensor circuit to alter the distance.
14. The method according to claim 11 , further comprising heating a heater element, the heater element being arranged at the tape bearing surface.
15. The method according to claim 14 , wherein sensing the distance between the tape bearing surface and the tape includes monitoring a temperature of the heater element.
16. The method according to claim 15 , wherein monitoring the temperature of the heater element includes measuring an electrical resistance of the heater element.
17. The method according to claim 14 , wherein sensing the distance between the tape bearing surface and the tape includes monitoring changes in voltage at the heater element measured by a voltage meter.
18. The method according to claim 14 , wherein sensing the distance between the tape bearing surface and the tape includes monitoring changes in current at the heater element measured by a current meter.
19. The method according to claim 13 , wherein altering said distance comprises applying a voltage to a plurality of electrostatic attractors to alter the distance according to the signal received from the tape-head distance sensor circuit.
20. The method according to claim 11 , further comprising keeping the distance substantially constant by providing a closed-loop feedback control of the distance.