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WO1997015516A1 - Suivi et mise au point dynamique pour systemes de bande optique - Google Patents

Suivi et mise au point dynamique pour systemes de bande optique Download PDF

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Publication number
WO1997015516A1
WO1997015516A1 PCT/US1995/013733 US9513733W WO9715516A1 WO 1997015516 A1 WO1997015516 A1 WO 1997015516A1 US 9513733 W US9513733 W US 9513733W WO 9715516 A1 WO9715516 A1 WO 9715516A1
Authority
WO
WIPO (PCT)
Prior art keywords
memory tape
memory
tape
roller
tension
Prior art date
Application number
PCT/US1995/013733
Other languages
English (en)
Inventor
William S. Oakley
Original Assignee
Lots Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Lots Technology filed Critical Lots Technology
Priority to PCT/US1995/013733 priority Critical patent/WO1997015516A1/fr
Priority to AU40096/95A priority patent/AU4009695A/en
Publication of WO1997015516A1 publication Critical patent/WO1997015516A1/fr

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/002—Recording, reproducing or erasing systems characterised by the shape or form of the carrier
    • G11B7/003—Recording, reproducing or erasing systems characterised by the shape or form of the carrier with webs, filaments or wires, e.g. belts, spooled tapes or films of quasi-infinite extent
    • G11B7/0031—Recording, reproducing or erasing systems characterised by the shape or form of the carrier with webs, filaments or wires, e.g. belts, spooled tapes or films of quasi-infinite extent using a rotating head, e.g. helicoidal recording
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B15/00—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function
    • G11B15/60—Guiding record carrier
    • G11B15/602—Guiding record carrier for track selection, acquisition or following

Definitions

  • the present invention relates to the field of memory tape drive and transport systems. More particularly, the present invention relates to the design of tape positioning mechanisms and tension measuring devices.
  • Data can be stored in a variety of different mediums.
  • One popular medium entails storing data onto a tape of a tape drive system.
  • the memory tape drive system transports memory tape 101 across a head 102 (also known as a transducer) for reading or recording.
  • many memory tape drive systems incorporate positioning mechanisms to position the memory tape in the proper location for reading or recording.
  • the positioning mechanism acts as an alternative to moving the head to track transverse tape motion.
  • One prior positioning mechanism utilized a tape edge guide to position the memory tape as shown in Figure 1.
  • the tape edge guide operates by spring fingers 103 applying a force on one edge of the memory tape against a ceramic base.
  • the recorded bit size is in the sub ⁇ micron range and the transverse tape motion caused by tape edge imperfections will cause recording of information in an unpredictable location on the memory tape.
  • One prior technique to compensate for transverse tape motion involves the use of a tracking actuator servo system where the optical recording lens follows the transverse tape motion.
  • the transverse tape motions contain high frequency components making it difficult for a tracking actuator servo system to follow the transverse tape motions.
  • the tracking actuator servo mechanism could not fully compensate for high frequency transverse tape movement.
  • the inability to compensate for transverse tape motion results in read out bit and tracking errors when using small bit sizes. This leads to the necessity of having to use larger bit sizes.
  • the disadvantage to using larger bit sizes is that the memory capacity diminishes.
  • a memory tape drive system incorporating a positioning mechanism which reduces high frequency components of transverse tape movement so that smaller bit sizes can be utilized to increase memory capacity of the memory tape.
  • the tape drive system transports memory tape by releasing the memory tape, positioning the memory tape in a predetermined position by applying differential stresses to the memory tape, and receiving the memory tape.
  • the tape drive system can include a device for adjusting the position of the memory tape. The device adjusts the position of the memory tape by tilting a roller about an axis perpendicular to the surface of the memory tape or by tilting a roller about an axis along the length of the memory tape.
  • the tape drive system can include a device to measure the tension of the memory tape and a device to cause a motor to change torque in response to the tension level.
  • the tape drive system can include a device to measure tension comprising a flexible mount which responds to tension levels by bending and a strain gage coupled to the flexible mount for measuring strain caused by the bending.
  • Figure 1 illustrates a prior art tape positioning mechanism
  • Figure 2 illustrates the tape positioning mechanism of one embodiment of the present invention.
  • Figure 3 illustrates the crowned roller of the tape positioning mechanism of Figure 2.
  • Figure 4 illustrates the tilt adjustment device of an alternative embodiment of the present invention.
  • Figure 5 illustrates the memory tape drive system of an alternative embodiment of the present invention.
  • Figure 6 illustrates a device for measuring tension of a tape drive system.
  • Figure 2 illustrates a positioning mechanism of one embodiment of the present invention.
  • the positioning mechanism comprises of crowned roller 201.
  • Memory tape 202 travels over crowned roller 201 and contacts crowned roller 201 causing crowned roller 201 to spin in the direction of travel of memory tape 202.
  • memory tape 202 travels underneath recording lens 203 and recording lens 203 then records information on memory tape 202.
  • While memory tape 202 travels over crowned roller 201 it may move slightly up or down in the transverse direction along the crowned roller.
  • crowned roller 201 applies differential stresses to memory tape 202.
  • the portion of memory tape 202 in contact with the center of crowned roller 201 experiences the most stress because it has the greatest contact with crowned roller 201.
  • the portions of memory tape 202 away from the center of crowned roller 201 experiences progressively less stress because it has progressively less contact with crowned roller 201.
  • the difference in stress translates to differences in stretching across the width of memory tape 202. Greater stress causes greater amounts of stretching.
  • This difference in stretching causes memory tape 202 to bow away from the center of crowned roller 201.
  • the bowing in turn causes memory tape 202 traveling towards crowned roller 201 to be slanted towards the center.
  • the slanting causes memory tape 202 to reposition itself on crowned roller 201.
  • the differential stresses causes memory tape 202 to move back to its original proper position. In this manner, crowned roller 201 keeps memory tape 202 in the correct position for recording of information by recording lens 203.
  • the transverse motion of memory tape 202 has lower frequency components.
  • the lower frequency components makes it easier for a tracking actuator servo system to follow the transverse motions of memory tape 202.
  • the tracking actuator servo system can more fully compensate for transverse motions in memory tape 202.
  • the compensation in turn provides improved data tracking and allows for optical recording with smaller bit sizes leading to increased memory tape capacity.
  • FIG. 3 illustrates in further detail crowned roller 201.
  • Crowned roller 201 has a crown height of 0.076mm (0.003") and a length of 13.00 ⁇ 0.02mm. The radius of curvature is 280.00mm (1 1.024").
  • crowned roller 201 has slots along the surface to bleed out air. When memory tape speeds reach 2 m/s, air can be trapped between the memory tape and crowned roller 201. The trapped air can cause the memory tape to lose contact with the surface of crowned roller 201. To remove the trapped air, crowned roller 201 includes slots along the surface as illustrated in Figure 3.
  • Moving memory tape 202 positions itself in a location depending on the tilt orientation of crowned roller 201.
  • the tilt orientation of crowned roller 201 can be adjusted.
  • Crowned roller 201 can be tilted about an axis perpendicular to the surface of memory tape 202 as shown in Figure 4 and crowned roller
  • tilt adjustment 201 can also be tilted about an axis along the length of memory tape 202. Either tilt adjustment will cause moving memory tape 202 to occupy a different position on crowned roller 201. However, the tilt adjustment has different effects on the position of moving memory tape 202 depending on the wrap angle of moving memory tape 202.
  • tape 202 has a high wrap angle
  • tape 202 is more sensitive to changes in the tilt orientation about an axis perpendicular to the surface of memory tape 202 than changes in the tilt orientation about an axis along the length of memory tape 202.
  • tape 202 is more sensitive to changes in the tilt orientation about an axis along the length of memory tape 202 than changes in the tilt orientation about an axis perpendicular to the surface of memory tape 202.
  • a one degree tilt about an axis along the length of memory tape 202 produces a 0.001 inch transverse change in the position of memory tape 202.
  • a ten degree tilt about an axis perpendicular to the surface of memory tape 202 is required to produce the same 0.001 inch transverse change in tape position.
  • FIG. 4 also illustrates in detail tilt adjustment device 501.
  • the tilt adjustment device comprises of T-plate 502, screw adjustments 503, screw adjustment 504, and complaint mount 505.
  • Screw adjustment 503 has a spring around it and is located at the end of one leg of T-plate 502.
  • Screw adjustment 504 also has a spring around it and is located on the other leg of T-plate 502, 90 degrees away from screw adjustment 503.
  • Complaint mount 505 is located at the intersection of the three legs of T- plate 502 and is made complaint by the use of Bellville washers.
  • FIG. 5 illustrates a memory tape drive system under an alternative embodiment of the present invention.
  • the memory tape drive system comprises of reel 301 which releases memory tape 202.
  • Memory tape 202 travels to crowned roller 302 causing crowned roller 302 to rotate in the direction of travel of memory tape 202.
  • Crowned roller 302 causes memory tape 202 to position itself at a predetermined location on crowned roller 302.
  • Memory tape 202 then travels to cylindrical roller 303 causing cylindrical roller 303 to rotate.
  • the optical writing zone is located slightly beyond the point where memory tape 202 contacts cylindrical roller 303 as shown in Figure 4.
  • memory tape 202 travels to cylinder roller 306 and then to crowned roller 304 causing crowned roller 304 to rotate in the direction of travel of memory tape 202.
  • Crowned roller 304 causes moving memory tape 202 to occupy a predetermined position on crowned roller 304. Finally, memory tape 202 travels to reel 305 which receives memory tape 202.
  • a motor is coupled to reel 305 providing torque to reel 305. The torque causes reel 305 to rotate and causes memory tape 202 to travel from reel 301 to reel 305.
  • a second motor is coupled to reel 301 providing torque to reel 301 in the opposite direction. In this manner, the torque applied to reel 305 and the opposite torque applied to reel 301 results in tension in memory tape 202.
  • the torque applied to reel 305 is greater than that applied to reel 301 causing memory tape 202 to travels towards reel 305.
  • the memory tape drive system In order to operate the memory tape drive system at higher tape speeds, tape tension control is required to minimize tape dynamic motion and tape velocity variations.
  • Prior memory tape drive systems controlled tape tension by first measuring tape tension utilizing air bearings and air pressure sensors. Then the control system adjusts accordingly.
  • the use of crowned rollers does not facilitate the use of air pressure sensors and air bearings because the crowned rollers require frictional forces to properly position the memory tape, and thus, require contact between it and the memory tape.
  • the memory tape drive system utilizes an alternative mechanism for measuring tape tension. As shown in Figure 6, the crowned roller is mounted on flexible mount 401. Tension on memory tape 202 causes a force to be generated on the crowned roller.
  • flexible mount 401 has parallel legs as shown in Figure 6.
  • the parallel legs allow flexible mount 401 to bend in response to the force generated by tape tension but at the same time maintains the same tilt orientation under varying tension levels.
  • the bending of flexible mount 401 in turn causes strain in flexible mount 401.
  • Strain gauge 402 is coupled to flexible mount 401 at the point of bending and measures the amount of the strain as shown in Figure 6. In this manner, tension on memory tape 202 is translated into strain appearing on strain gauge 402.
  • Strain gauge 402 is coupled to a control device which monitors strain gauge 402.
  • the control device is coupled to the motor driving reel 305 and causes the motor to change the torque applied to reel 305 in response to strain levels appearing on strain gauge 402.
  • strain gauge 402 indicates greater strain, thus greater tension
  • the control device causes the motor to apply less torque to reel 305.
  • strain gauge 402 senses less strain, thus less tension
  • the control device causes the motor to apply greater torque to reel 305.
  • the control device is also coupled to the second motor driving reel 301 and causes the second motor to change the torque applied to reel 301 in response to strain levels appearing on strain gauge 402.
  • strain gauge 402 indicates greater strain, thus greater tension
  • the control device causes the motor to apply less torque to reel 301. In this manner, tape tension is kept to a predetermined level.

Landscapes

  • Registering, Tensioning, Guiding Webs, And Rollers Therefor (AREA)

Abstract

L'invention porte sur un mécanisme d'entraînement de bande de mémoire. Ce mécanisme transporte une bande de mémoire (202) en relâchant (301) la bande de mémoire (202), en la positionnant sur un emplacement prédéterminé par l'application d'une force (201) sur sa surface et en recevant (305) cette bande de mémoire (202).
PCT/US1995/013733 1995-10-23 1995-10-23 Suivi et mise au point dynamique pour systemes de bande optique WO1997015516A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/US1995/013733 WO1997015516A1 (fr) 1995-10-23 1995-10-23 Suivi et mise au point dynamique pour systemes de bande optique
AU40096/95A AU4009695A (en) 1995-10-23 1995-10-23 Dynamic tracking and focus for optical tape systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US1995/013733 WO1997015516A1 (fr) 1995-10-23 1995-10-23 Suivi et mise au point dynamique pour systemes de bande optique

Publications (1)

Publication Number Publication Date
WO1997015516A1 true WO1997015516A1 (fr) 1997-05-01

Family

ID=22250033

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1995/013733 WO1997015516A1 (fr) 1995-10-23 1995-10-23 Suivi et mise au point dynamique pour systemes de bande optique

Country Status (2)

Country Link
AU (1) AU4009695A (fr)
WO (1) WO1997015516A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0944065A2 (fr) * 1998-03-19 1999-09-22 Matsushita Electric Industrial Co., Ltd. Appareil d'enregistrement/reproduction magnétique
US6137649A (en) * 1998-03-19 2000-10-24 Matsushita Electric Industrial Co., Ltd. Magnetic recording/reproduction apparatus in which one of a reel base pair is rotated to wind a magnetic tape by a predetermined amount when an abnormality is detected
US6198592B1 (en) 1998-03-19 2001-03-06 Matsushita Electric Industrial Co., Ltd. Magnetic recording/reproduction apparatus including a first chassis onto which a tape cassette is received and a second chassis having a rotary head cylinder thereon
US6286775B1 (en) 1998-03-19 2001-09-11 Matsushita Electric Industrial Co. Ltd. Magnetic recording apparatus

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3497154A (en) * 1968-03-29 1970-02-24 Ampex Tape tension means
US3910527A (en) * 1974-03-08 1975-10-07 Ibm Web distribution controlled servomechanism in a reel-to-reel web transport
US4310863A (en) * 1979-05-04 1982-01-12 Enertec Magnetic tape recorders
US4703372A (en) * 1985-03-08 1987-10-27 Spacelabs, Inc. Portable electrocardiographic recorder
US4913328A (en) * 1987-06-05 1990-04-03 Odetics, Inc. Active tape tracking system with crown guide rollers for magnetic recorder/players

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3497154A (en) * 1968-03-29 1970-02-24 Ampex Tape tension means
US3910527A (en) * 1974-03-08 1975-10-07 Ibm Web distribution controlled servomechanism in a reel-to-reel web transport
US4310863A (en) * 1979-05-04 1982-01-12 Enertec Magnetic tape recorders
US4703372A (en) * 1985-03-08 1987-10-27 Spacelabs, Inc. Portable electrocardiographic recorder
US4913328A (en) * 1987-06-05 1990-04-03 Odetics, Inc. Active tape tracking system with crown guide rollers for magnetic recorder/players

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0944065A2 (fr) * 1998-03-19 1999-09-22 Matsushita Electric Industrial Co., Ltd. Appareil d'enregistrement/reproduction magnétique
EP0944065A3 (fr) * 1998-03-19 1999-10-27 Matsushita Electric Industrial Co., Ltd. Appareil d'enregistrement/reproduction magnétique
US6137649A (en) * 1998-03-19 2000-10-24 Matsushita Electric Industrial Co., Ltd. Magnetic recording/reproduction apparatus in which one of a reel base pair is rotated to wind a magnetic tape by a predetermined amount when an abnormality is detected
US6198592B1 (en) 1998-03-19 2001-03-06 Matsushita Electric Industrial Co., Ltd. Magnetic recording/reproduction apparatus including a first chassis onto which a tape cassette is received and a second chassis having a rotary head cylinder thereon
US6282057B1 (en) 1998-03-19 2001-08-28 Matsushita Electric Industrial Co., Ltd Magnetic recording/reproduction apparatus, with inclination adjusting system
US6286775B1 (en) 1998-03-19 2001-09-11 Matsushita Electric Industrial Co. Ltd. Magnetic recording apparatus

Also Published As

Publication number Publication date
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