Improvement of protection process using observer for soild imersion lens-based near-field recording

Hyunwoo Hwang, Sang Hoon Kim, Jung Gon Kim, Tae Wook Kwon, Hyunseok Yang, No Cheol Park, Young Pil Park

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

In the near field recording (NFR) system, there always exists the possibility of collision between solid imersion lens (SIL) and media owing to dust, scratches on the media, and external shock because of the extremely small gap distance. The kinetic energy associated with damage from shock is directly proportional to the square of velocity, and the phase of velocity is faster than the phase of displacement with 90°. Thus, it is effective to prevent a collision on the basis of velocity information. The velocity of the actuator in the NFR system should be estimated by an observer without using a velocity sensor. In this paper, we propose an improved protection process with a mode switching servo method using a Luenberger observer. The gap distance state can be estimated earlier by detecting the velocity state yielded by external shock. Through simulations and experiments, we confirm that the protection process based on velocity and gap distance is more powerful than the protection process based only on the gap distance.

Original languageEnglish
Article number03A046
JournalJapanese journal of applied physics
Volume48
Issue number3 PART 2
DOIs
Publication statusPublished - 2009 Mar 1

Fingerprint

Lenses
near fields
recording
lenses
shock
collisions
Kinetic energy
Dust
Actuators
actuators
dust
kinetic energy
damage
sensors
Sensors
simulation
Experiments

All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Physics and Astronomy(all)

Cite this

Hwang, Hyunwoo ; Kim, Sang Hoon ; Kim, Jung Gon ; Kwon, Tae Wook ; Yang, Hyunseok ; Park, No Cheol ; Park, Young Pil. / Improvement of protection process using observer for soild imersion lens-based near-field recording. In: Japanese journal of applied physics. 2009 ; Vol. 48, No. 3 PART 2.
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Improvement of protection process using observer for soild imersion lens-based near-field recording. / Hwang, Hyunwoo; Kim, Sang Hoon; Kim, Jung Gon; Kwon, Tae Wook; Yang, Hyunseok; Park, No Cheol; Park, Young Pil.

In: Japanese journal of applied physics, Vol. 48, No. 3 PART 2, 03A046, 01.03.2009.

Research output: Contribution to journalArticle

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