Radial servo device for super-resolution optical disc and servo control method therefor

Patent metadata

Field	Value
Publication number	US-11227632-B2
Application number	US-201917050271-A
Country	US
Kind code	B2
Filing date	Apr 16, 2019
Priority date	Apr 26, 2018
Publication date	Jan 18, 2022
Grant date	Jan 18, 2022

Abstract

A radial servo control device for a super-resolution optical disc includes an excitation light source, a servo light source, an integrated optical path, focusing units, a servo light detecting unit and a drive control unit; the drive control unit presets N detection error reference values with respect to each guide layer trench irradiated by servo light, and controls corresponding positions of the focusing units in N data tracks below each guide layer trench according to a comparison result between a detection result of servo reflected light and the detection error reference values. The device is applicable to a variety of super-resolution optical discs on the basis of stimulated radiation loss microscopy technology, a two-photon absorption technology, and the like, and achieves accurate radial servo control of super-resolution data tracks (<100 nm) without reducing the wavelength of servo light and the width of guide layer trenches.

First claim

The invention claimed is:

1. A servo device for a super-resolution optical disc, comprising an excitation light source, servo light source, integrated optical path, focusing unit, servo light detection unit, and drive control unit;
the excitation light source emits excitation light, and the servo light source emits servo light, and the excitation light and the servo light reach the focusing unit through the integrated optical path, being focused on the disc surface, the servo light passes through the focusing unit again after being reflected on the disc surface, and then the reflected light is detected by the servo light detection unit, and the detection result is transmitted to the drive control unit;
the excitation light source comprises at least one laser light source with a single wavelength or laser light source with different wavelengths;
the integrated optical path at least comprises a collimator lens, which integrates the servo light and the excitation light to form a coaxial circular parallel beam;
the focusing unit at least comprises an optical element capable of focusing and focuses the excitation light and the servo light on the same axis;
the servo light detection unit detects the servo reflected light beam generated by the servo light beam converged by the focusing unit and reflected by a servo guide layer of the super-resolution optical disc;
the drive control unit presets N detection error reference values for the detection signal of the reflected light generated by the servo guide layer of the servo light irradiating optical disc, and controls the radial position of the focusing unit according to a comparison result of the detection result of the servo reflected light and the detection error reference value, wherein N is an integer greater than 1.

2. The servo device for a super-resolution optical disc according to claim 1 , wherein, the servo device is used for a super-resolution optical disc, and the super-resolution optical disc comprises a multi-layer structure, which comprises a servo guide layer containing a spiral groove shape and at least one data recording layer existing thereunder;
data storage units are distributed in a spiral form in the data recording layer, the data storage units on each spiral constituting a data storage track, wherein every N data storage tracks correspond to a groove in the servo guide layer, and N is an integer greater than 1.

3. The servo device for a super-resolution optical disc according to claim 2 , wherein, the smallest size of the data storage units is smaller than the diffraction limit of an excitation light of an excitation light source.

4. The servo device for a super-resolution optical disc according to claim 1 , wherein, the super-resolution optical disc adopts the methods comprising super-resolution fluorescence microscopy, two-photon absorption technology, super-resolution optical filtering technology, and medium super-resolution technology to produce a recording point smaller than the diffraction limit of the excitation light.

5. The servo device for a super-resolution optical disc according to claim 4 , wherein, the super-resolution fluorescence microscopy comprises stimulated radiation loss microscopy.

6. The servo device for a super-resolution optical disc according to claim 5 , further comprising a loss light source ( 103 ), collimator lens ( 211 ), ½ wave plate ( 215 ), and polarization beam splitter ( 216 ), vortex phase plate ( 217 ), the excitation light source ( 101 ), collimator lens ( 201 ), ½ wave plate ( 212 ), polarizing beam splitter ( 213 ), dichroic mirror ( 214 ), relay lens ( 203 ), dichroic mirror ( 206 ), relay lens ( 207 ), reflector ( 210 ), dichroic mirror ( 218 ), ¼ wave plate ( 209 ), objective lens ( 401 ), filter ( 220 ), astigmatic lens ( 221 ), photodetector ( 302 ), the servo laser light source ( 102 ), collimator lens ( 202 ), polarization beam splitter ( 205 ), relay lens ( 204 ), focusing lens ( 208 ), photodetector ( 301 ), two-dimensional translation stage ( 502 ) for the placement of the objective lens ( 401 ), and one-dimensional translation stage ( 503 ) for the placement of the relay lens ( 204 );
the light beam emitted from the loss light source ( 103 ) passes through the collimator lens ( 211 ), the ½ wave plate ( 215 ), the polarization beam splitter ( 216 ) and the vortex phase plate ( 217 ) in sequence, and then incident on the dichroic mirror ( 214 ), and reflected by the dichroic mirror ( 214 ) to form a first reflected light;
the light beam emitted from the excitation light source ( 101 ) passes through the collimator lens ( 201 ), the ½ wave plate ( 212 ) and the polarizing beam splitter ( 213 ) in sequence, and then incident on the dichroic mirror ( 214 ), and transmitted by the dichroic mirror ( 214 ) to form a first transmitted light;
the first reflected light and the first transmitted light are combined by the dichroic mirror ( 214 ), then incident on the dichroic mirror ( 206 ) through the relay lens ( 203 ), and then transmitted by the dichroic mirror ( 206 ) to form a second transmitted light;
the second transmitted light passes through the relay lens ( 207 ) and the reflector ( 210 ) in sequence, and then incident on the dichroic mirror ( 218 ), and transmitted by the dichroic mirror ( 218 ) to form a third transmitted light;
the third transmitted light passes through the ¼ wave plate ( 209 ) and the objective lens ( 401 ) in sequence, and then incident on the Nth recording layer ( 002 ) of the super-resolution optical disc ( 001 ), the fluorescence signal generated is collected by the objective lens ( 401 ), and then incident on the dichroic mirror ( 218 ) through the ¼ wave plate ( 209 ), and reflected by the dichroic mirror ( 218 ) to form a second reflected light;
the second reflected light passes through the filter ( 220 ) and the astigmatic lens ( 221 ) in sequence, and reaches the photodetector ( 302 );
the light beam emitted from the servo laser light source ( 102 ) is incident on the polarization beam splitter ( 205 ) through the collimator lens ( 202 ), and reflected by the polarization beam splitter ( 205 ) to form a third reflected light with a first linear polarization state;
the third reflected light is incident on the dichroic mirror ( 206 ) through the relay lens ( 204 ), and reflected by the dichroic mirror ( 206 ) to form a fourth reflected light;
the fourth reflected light passes through the relay lens ( 207 ), the reflector ( 210 ), the dichroic mirror ( 218 ), the ¼ wave plate ( 209 ) and the objective lens ( 401 ) in sequence, and incident on the servo-guide layer ( 004 ) of the super-resolution optical disc ( 001 ), and reflected by the servo-guide layer ( 004 ) to form a fifth reflected light;
the fifth reflected light is incident on the ¼ wave plate ( 209 ) through the objective lens ( 401 ), and becomes the fifth reflected light with a second linear polarization state through the ¼ ( 209 ) wave plate;
the fifth reflected light with the second linear polarization state passes through the dichroic mirror ( 218 ), the reflector ( 210 ), and the relay lens ( 207 ) in sequence, and incident on the dichroic mirror ( 206 ), and reflected by the dichroic mirror ( 206 ) to form a sixth reflected light;
the sixth reflected light is incident on the polarization beam splitter ( 205 ) through the relay lens ( 204 ), and transmitted by the polarization beam splitter ( 205 ) to form a fourth transmitted light;
the fourth transmitted light reaches the photodetector ( 301 ) through the focusing lens ( 208 );
the photodetector ( 301 ) respectively connected to the two-dimensional translation stage ( 502 ) and the one-dimensional translation stage ( 503 ) via a servo control computing module ( 501 ).

7. The servo device for a super-resolut

Assignees

• Shanghai Inst Optics & Fine Mech Cas

Inventors

• Ruan Hao
• Hu Qiao
• Yuan Xupeng
• Guo Xinjun

Classifications

• G11B7/1395

  Beam splitters or combiners (G11B7/1353, G11B7/1356 take precedence {; beam splitting or combining per se G02B27/10}) · CPC title

• G11B7/08552

  using electro-optical elements · CPC title

• G11B7/0901 Primary

  for track following only (G11B7/0925, G11B7/094, G11B7/0941, G11B7/0943, G11B7/0945, G11B7/0946, G11B7/0948 take precedence) · CPC title

• G11B7/093

  for focusing and tracking (G11B7/0932 - G11B7/0937 take precedence) · CPC title

• G11B7/24065

  Layers assisting in recording or reproduction below the optical diffraction limit, e.g. non-linear optical layers or structures (cover layers for near-field media G11B7/24059) · CPC title