Optical medium reproduction device and optical medium reproduction method

Patent metadata

Field	Value
Publication number	US-9843389-B2
Application number	US-201414910396-A
Country	US
Kind code	B2
Filing date	Jun 26, 2014
Priority date	Aug 14, 2013
Publication date	Dec 12, 2017
Grant date	Dec 12, 2017

Abstract

There is provided an optical medium reproduction device that optically reproduces an optical medium in which a plurality of tracks are provided, the optical medium reproduction device including: a detection unit configured to divide a cross-section of a beam returning from the optical medium into at least one channel corresponding to an outer region in a radial direction, at least one channel corresponding to a region that is different in position in a tangential direction, and a channel corresponding to the other region, and form detection signals of the channels; a multi-input equalizer unit including a plurality of equalizer units to which the detection signals of the plurality of channels are supplied, respectively, the multi-input equalizer unit being configured to calculate outputs of the plurality of equalizer units and output the outputs as an equalized signal in a manner that a phase difference between two of the regions is set to be a predetermined phase difference; and a binarization unit configured to perform a binarization process on the equalized signal to obtain binary data.

First claim

The invention claimed is:

1. An optical medium reproduction device that optically reproduces an optical medium in which a plurality of tracks are provided, the optical medium reproduction device comprising:
a detection unit configured to:
divide a cross-section of a beam returning from the optical medium into a plurality of channels, the plurality of channels comprising a channel corresponding to a central region, at least one channel corresponding to an outer region in a radial direction, and at least one channel corresponding to a region that is different in position from the central region in a tangential direction, and
form a plurality of detection signals, wherein each detection signal of the plurality of detection signals is formed from one or more of the plurality of channels;

a multi-input equalizer unit including a plurality of equalizer units, wherein each equalizer unit of the plurality of equalizer units is configured to:
receive one of the plurality of detection signals; and
calculate an output of the equalizer unit by applying an equalizer filter to the received detection signal,
wherein the multi-input equalizer unit is configured to sum the outputs of the plurality of equalizer units to generate an equalized signal, and
wherein one or more of the equalizer filters is configured to generate a target phase difference between the outputs of two of the equalizer units corresponding to two respective regions; and

a binarization unit configured to receive the equalized signal from the multi-input equalizer unit and perform a binarization process on the equalized signal to obtain binary data.

2. The optical medium reproduction device according to claim 1 ,
wherein the multi-input equalizer unit is configured as a multi-input adaptive equalizer unit, and
wherein the optical medium reproduction device includes an equalization error calculation unit configured to calculate an equalization error by using an equalization target signal obtained on the basis of a binarization detection result of the binarization unit and the equalized signal output from the multi-input adaptive equalizer unit and supply the equalization error to the multi-input adaptive equalizer unit as a control signal for adaptive equalization.

3. The optical medium reproduction device according to claim 2 ,
wherein the multi-input adaptive equalizer unit performs a partial response equalization process on the plurality of detection signals,
wherein the binarization unit performs a maximum likelihood decoding process as the binarization process performed on the equalized signal of the multi-input adaptive equalizer unit, and
wherein the equalization error calculation unit is configured to calculate an equalization error using 1) the equalization target signal obtained by performing a convolution process with the binarization detection result obtained by the maximum likelihood decoding process and 2) the equalized signal output from the multi-input adaptive equalizer unit.

4. The optical medium reproduction device according to claim 1 ,
wherein the detection unit includes divided detectors corresponding to the plurality of regions, and
wherein the plurality of detection signals are extracted from the detection unit.

5. The optical medium reproduction device according to claim 1 ,
wherein an optical path conversion element that separates the plurality of regions is provided in an optical path leading to the detectors through an objective lens, and
wherein a plurality of beams separated by the optical path conversion element are input to the different detectors.

6. The optical medium reproduction device according to claim 1 ,
wherein lands and grooves are alternately provided in the optical medium, and
wherein information is recorded on both the lands and the grooves.

7. The optical medium reproduction device according to claim 1 , wherein each equalizer filter is a finite impulse response filter.

8. The optical medium reproduction device according to claim 1 , wherein the region that is different in position from the central region in the tangential direction is a first tangential region, and further wherein the detection unit is further configured to divide the cross-section of the beam returning from the optical medium into at least one channel corresponding to a second tangential region that is different in position from the central region in the tangential direction.

9. The optical medium reproduction device according to claim 1 , wherein the equalizer unit corresponding to the outer region in the radial direction is configured to output a signal with a phase shifted by 180 degrees from the output of the equalizer unit corresponding to the central region.

10. The optical medium reproduction device according to claim 1 , wherein the equalizer unit corresponding to the region that is different in position from the central region in the tangential direction is configured to output a signal with a phase shifted by 180 degrees from the output of the equalizer unit corresponding to the central region.

11. The optical medium reproduction device according to claim 1 , wherein the target phase difference between the outputs of two of the equalizer units corresponding to two respective regions is determined based on frequency components of the respective outputs.

12. An optical medium reproduction method for optically reproducing an optical medium in which a plurality of tracks are provided, the optical medium reproduction method comprising:
dividing a cross-section of a beam returning from the optical medium into a plurality of channels, the plurality of channels comprising a channel corresponding to a central region, at least one channel corresponding to an outer region in a radial direction, and at least one channel corresponding to a region that is different in position from the central region in a tangential direction;
forming a plurality of detection signals, wherein each detection signal of the plurality of detection signals is formed from one or more of the plurality of channels;
receiving, by each equalizer unit of a plurality of equalizer units included in a multi-input equalizer input, one of the plurality of detection signals;
calculating, by each equalizer unit, an output of the equalizer unit by applying an equalizer filter to the received detection signal; and
outputting, by the multi-input equalizer unit, the sum of the outputs of each of the plurality of equalizer units as an equalized signal,
wherein one or more of the equalizer filters are configured to generate a target phase difference between the outputs of two of the equalizer units corresponding to two respective regions; and
performing, using a binarization unit, a binarization process on the equalized signal output by the multi-input equalizer unit to obtain binary data.

13. An optical medium reproduction device that optically reproduces an optical medium in which a plurality of tracks are provided, the tracks encoding data using a plurality of marks on the optical medium, the optical medium reproduction device comprising:
a detection unit configured to:
divide a cross-section of a beam returning from the optical medium into a plurality of channels, the plurality of channels comprising a channel corresponding to a central region, at least one channel corresponding to an outer region in a radial direction, and at least one channel corresponding to a region that is different in position from the central region in a tangential direction;
form a plurality of detection signals, wherein each detection signal is formed from one or more of the plurality of channels;

a multi-input equalize

Assignees

• Sony Corp

Inventors

• Nishi Noriaki
• Saito Kimihiro
• Shiraishi Junya

Classifications

• H04L25/03006

  Arrangements for removing intersymbol interference · CPC title

• G11B7/131

  Arrangement of detectors in a multiple array · CPC title

• H04B10/0795

  Performance monitoring; Measurement of transmission parameters · CPC title

• G11B20/10046

  filtering or equalising, e.g. setting the tap weights of an FIR filter · CPC title

• G11B20/10009 Primary

  Improvement or modification of read or write signals · CPC title