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Positioning Apparatus for Hard Disk Servowriter

Summary

By using an auto focus encoder, the present invention, positioning apparatus for hard disk servowriter, provides the precise positioning of the servo pattern writing heads required for successful servowriting. The new apparatus also relates to a track position sensor for providing track position of read/write (R/W) heads of hard disk assembly (HDA) instead of conventional servo pattern. This new invention introduces the device and method for sensing the position of servowriter heads, which is accurate, compact, and economic to manufacture.

As the capacity and performance of hard disks continue to advance, the ability to provide higher resolution track position signal for R/W head of HDA is becoming more and more important. In recent years, the requirement for head position accuracy when servowriting has already reached 1% per track pitch. With such stringent position accuracy requirements, a precise position sensing scheme is imperative. Existing sensing methods and systems are usually of high resolution and accuracy but are also expensive, very complicated, time-consuming, bulky, and sensitive to vibration, contamination and electromagnetic interference.

Related patent: "Auto Focus Laser Encoder Having Three Light Beams and a Reflective Grating" (US patent no. 5,835,023, HKUST ref.: TTC.PA.049)

Technology Benefits

1. Low cost
2. Compact in size
3. Better resolution (better than 0.1?Ym even without interpolation)
4. Accuracy close to that of laser interferometers
5. High ability of anti-turbulence
6. Ready for mass production using existing CD, DVD and photolithography technologies

Technology Application

- Hard disk and hard disk drive servowriter

Supplementary Information

Patent Number: US6191911B1
Application Number: US199896177A
Inventor: Cai, Lilong | Zhou, Weidong
Priority Date: 12 Jun 1998
Priority Number: US6191911B1
Application Date: 12 Jun 1998
Publication Date: 20 Feb 2001
IPC Current: G11B0005596
US Class: 36007703 | 250237G | 360075 | 36007811 | G9B005223 | G9B005226 | G9B005228
Assignee Applicant: The Hong Kong University of Science & Technology
Title: Positioning apparatus for hard disk servowriter
Usefulness: Positioning apparatus for hard disk servowriter
Summary: For servo writer of hard disk drive.
Novelty: Servo write head position and movement sensing apparatus has actuator for driving the grating with two parallel reflection grating sections and servo write head together

Industry

Electronics

Sub Group

Computer System

Application Date

12 Jun 1998

Application No.

US 09/096177

Patent Information

US 6191911

ID No.

TTC.PA.078

Country/Region

Hong Kong

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