JPS62229532A - Write/read tracking system for optical recording medium - Google Patents

Abstract

PURPOSE:To easily and inexpensively realize an increase in the recording capacity without specifically high accuracy by setting plural data tracks in one data recording area remarkably increase the recording capacity. CONSTITUTION:A recording area 2 of a recording medium is provided on a card base of an optical recording medium 1, plural tracking lines 4 of strip shape are arranged to the region 2 at a prescribed interval, the strip area clipped by the lines 4 is used as a data recording area 3 and two data tracks Da, Db are provided at each area 3. The tracks Da, Db are set at a position (e) from the center of tracking lines 4a, 4b. Further, tracking line tracing detection areas Ta, Tb are provided at a prescribed interval in the broadwise direction of the area 3 and a write/read work area WR is arranged in between. Then plural data tracks are set to the area 3 to increase inexpensively and easily the recording capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application J] The present invention is directed to recording data tracks along the tracking lines in a band-shaped data recording area that is set between tracking lines that are arranged in parallel at regular intervals of 1 m. This invention relates to a JI-inclusive/read tracking method for optical recording media that sets

[Prior Art] Optical recording media developed in recent years are characterized by extremely large recording capacities compared to conventional magnetic recording media. This is only because data can be recorded at high 'ff: degrees on the micro-surface implant. In order to record and reproduce data at high density in such a small area, it is necessary for the write/read element to accurately track the data track on which data is to be recorded.

Conventionally, as an L stage for this purpose, a band-shaped data recording area is set between tracking lines arranged in parallel at regular intervals, and two tracking lines sandwiching the recording area are used as tracking line tracking sensors. There is a method of setting a data track in the center of the data recording area while tracking the data.

This method has a configuration in which data is written or read while tracking two tracking lines that sandwich a recording area, so that highly accurate writing and reading is possible.

[Problems to be Solved by the Invention] By the way, in the conventional method described above, one data track is provided in one strip-shaped data recording area, so the entire recording area of the optical recording medium is divided into two data trunks and one data track. The tracking lines are arranged alternately. Therefore, in this conventional method, the data recording capacity (IQ) is determined by the interval between the tracking lines. Therefore, in order to increase the data recording capacity, it is necessary to narrow the spacing between the tracking lines.

However, when the spacing between the tracking lines is narrowed, it becomes necessary to arrange the tracking line tracking sensor and the writing/reading element f therebetween with high precision in a smaller range. Although this is not technically impossible, it has the disadvantage that it requires particularly high precision, is not suitable for large HH production, and is therefore expensive.

The present invention was made in order to solve the above-mentioned drawbacks, and it is possible to set a plurality of data tracks in one data recording area, to record data at high density, and to significantly increase the recording capacity. Moreover, it is an object of the present invention to provide a tracking method for writing/reading an optical recording medium that can be realized without particularly requiring high viscosity and can increase the recording capacity tt at low cost and easily.

[Means for Solving the Problems] The present invention provides an optical recording system in which data tracks are set along tracking lines in a band-shaped data recording area set between tracking lines arranged in parallel at regular intervals. This is a tracking method for writing/reading media, and includes at least two detection areas for tracking line tracking, which are optical areas for detecting the displacement of the tracking line in the field of view, in the width direction of the data recording area. At the same time, write or read action areas, which are optical areas for writing or reading, are placed at appropriate positions from these tracking line tracking detection areas, and each tracking line The positional relationship between the tracking detection area and the writing or reading area is such that when the tracking detection area is tracking the tracking line at any location, the writing or reading area is used for data recording. When the writing or reading area is located on any corresponding data track L in the area and another tracking line tracking detection area is tracking the tracking line, the writing or reading area is located on any other data track L in the data recording area. It is characterized in that it is set to be located on track L.

The present invention provides means for setting a plurality of data tracks in one data recording area to enable high-density recording. The present invention allows various types of fB, but the most typical one is two types of fB in one data recording area.
It is of double density format forming a tree data track.

[Function] The present invention improves the arrangement interval between the write or read operation area, which is an optical area for writing or reading data, and the tracking line tracking detection area, which is an optical area for tracking each tracking line. By setting as described above, when any tracking line tracking detection area tracks any tracking line, data is written at a specific position in the width direction of the data recording area with this tracking line as a reference. A write or read action area is placed, and a data track is set here. Therefore, by providing tracking line tracking detection areas at multiple locations, one tracking line adjacent to the data recording area to be written or read, or in combination with other tracking lines installed in parallel with these, can be detected at one location. A plurality of data tracks can be set at positions in the width direction of the data recording area of the book.

[Example] Embodiments of the present invention will be described with reference to the drawings.

Structure of First Embodiment> FIGS. 1 and 2 show a first embodiment of a tracking system for writing and reading an optical recording medium of the present invention.

This embodiment is applied to an optical recording medium l of the form shown in FIG. This optical recording medium 1 has a recording area 2 provided with a recording medium on a card-shaped substrate, and a large number of belt-shaped tracking lines 4 are arranged at regular intervals in this recording area 2, and these trunking lines In this embodiment, two data tracks Da and ob are set for each data recording area 3 to perform double-density recording.

In FIGS. 1 and 2, a data recording area 3 in which data is written or read by the tracking method of this embodiment is formed into a band shape sandwiched between band-shaped tracking lines 4a and 4b.

In this embodiment, two data tracks Db and Da are arranged in parallel in this data recording area 3, and the data track Db is located at a position e from the center of the tracking line 4d, and the data track Da is located at a position e from the center of the tracking line 4d. Each is set at a position e from the center of the tracking line 4b. Note that here, for convenience of explanation, tracking line 4 is
Although subscripts a and b are given, the relationships with the two data tracks Db and Da are all the same for the other tracking lines 4 without subscripts.

As shown in these figures, the tracking method of this embodiment has two trunking line tracking detection areas rd,
rb are arranged at predetermined intervals in the width direction of the data recording area 3, and a write or read action area WR is arranged at an appropriate position between these tracking line tracking detection areas Ta and Tb.

In addition, in this embodiment, the write or read operation area WR
and the two tracking line tracking detection areas Ta and Tb sandwiching this. 4b), the write or read action area WR is located on one data track (Db in FIG. 1) h in the data recording area 3, and the tracking line tracking detection area T a .

The other side of Tb (Ta in Figure 2) is the tracking line (
In FIG. 2, when tracking 4a), the writing or reading area WR is the other data in the data recording area 3!・Set to be located at the rank (pa in FIG. 2).

For example, the detection areas Ta and Tb for tracking line L and the reading action area WR include the fourth
It is formed using an optical system as shown in the figure.

That is, the optical system shown in the figure uses a light source 6 such as a semiconductor laser.
, a collimating lens 7 that converts the light emitted from the light source into an f-row beam, a diffraction grating 8 that divides the light beam into three beams, and a beam splitter 7 that separates transmitted light and reflected light.
9, a quarter-wave plate lO which makes the polarization planes of the incident light on the optical recording medium and the reflected light perpendicular to each other, and a plate objective lens 11.

This optical system can be used for both writing and reading. In this case, when writing, the output energy of the light source 6 is increased to irradiate the data recording area with a high-energy light beam spot to locally melt or blacken the area. By changing reflection, 8 pieces of data can be stored. During reading, the light energy irradiated to the data recording area is weakened so that each part of the data recording area does not change. The data is converted into digital information and expressed as, for example, the presence or absence of a point 5, and then written.

Of the three light beams separated by the diffraction grating 8, the beam in the center is a beam for writing or reading, and the light beams on both sides are beams for tracking the tracking line. The arrangement of these beams corresponds to the writing or reading action area WR and the tracking line tracking detection areas T3 and Tb described above. That is, in this embodiment, these beams form the writing or reading action area 11R and the tracking line tracking detection areas "ra," rb.

Here, as shown in FIG. 1, the writing or reading action area WR and the tracking line tracking detection areas "ra," rb are band-shaped, sandwiching the data recording area 3 located at an arbitrary position on the recording area 2. The distance between the tracking lines 4a and 4b is d, and the detection area for tracking line "ra,"
``The distance between ``rb and the write or read action area WR is f.
Then, there is a relationship f=de between these.

A light receiving element/group P is provided together with the h2 optical system, and functions as a tracking line tracking and reading sensor by receiving a light beam taken out of the optical system at a beam submerger 9.

The group P of the photodetector elements Y consists of an i-conductor photodetector JT- such as a PIN photodiode. In this embodiment, as shown in FIG. configured. Here, two elements P1 and P2 1
A set of two, T-P6 and PI, are used for tracking line tracking, and the former corresponds to the detection area Tb,
The latter corresponds to the detection area Ta. In addition, elements P3 to P5
is used for reading.

The write or read action area WR and tracking line tracking detection areas T a and T b described above are used to align the write or read action area WR with either of the two data tracks D4 or Dh. The objective lens 11 is moved to shift in the direction in which the elementary fnPs are arranged. That is, in this embodiment, by this shift, the element T
- When the boundary line between PI and P2 and the center line of the tracking line 4b coincide, the boundary line between element fPa and P5 is on the center line of data trunk Db, and -.
When the boundary line between ib and Pl and the center line of the tracking line 4a are aligned, the boundary line between the elementary FP3 and P4 is arranged on the center line of the data track Da. FIG. 5 shows the former situation.

A set of two photodetectors TF+ and P2, and photodetector 'f
A pair of Pb and PI functions equally. In other words, the detection areas Ta and Tb are such that when the tracking line 4 is captured with its center not displaced within the field of view, the amount of light received by adjacent elements is large and the brightness distribution is simple. It becomes almost equal between f. On the other hand, when the tracking line is located in the - part of the visual field, the amount of light received is small and the brightness distribution is uneven. In this embodiment, this property is utilized to track the tracking line. conduct.

Figure 6 shows the tracking circuit. The tracking circuit shown in the figure consists of two systems, one for trunking A and one for tracking B, which are selected by a tracking A selection signal or a tracking B selection signal. That is, this tracking circuit includes an amplifier 12 to which E-type photodetectors fPI and P6, which serve as tracking sensors, and P2 and Pl are connected, and each amplifies the photoelectric output.
a.

12b, 12c and 12d and their amplifier 12c
, 12d, a difference circuit 13a that takes out a difference signal A from the outputs of the amplifiers 12a and 1211, an amplifier 15 that amplifies the outputs of the difference circuits 13b and l3a, and a difference circuit An analog switch 14b is connected to the differential circuit 13b and connects the output of the differential circuit 13b to the amplifier 15 in response to the tracking B selection signal; Amplifier 15
and an analog switch l 4 a connected to.

<Operation of the embodiment> Next, regarding the operation of this embodiment, taking data reading as an example,
This will be explained with reference to the drawings. Note that in the case of writing (7), the tracking effect is exactly the same as in the case of reading.

Now, suppose that in the recording area 2, data stored in an arbitrary data recording area 3 is to be read.

In the optical system, light from a light source 6 passes through a collimating lens 7,
3. Through the diffraction grating 8. The beam is divided into t beams and irradiated onto the optical recording medium 1 through the beam splitter 9, the quarter-wave plate 10, and the objective lens 11, respectively. Here, the reflected light returns to the beam splitter 9 via an objective lens 11 and a quarter-wave plate 10. By the way, since each beam passes back and forth through the quarter-wave plate 10, the plane of polarization of the one reflected light is rotated by 90 degrees compared to the light from the light source 6, so the beam splitter 9 It is reflected and emitted to the outside of the optical system.

When this emitted light enters the light-receiving element group P, the three light beams form an active area WR for M-containing or reading and a detection area TJ, Tb for tracking line tracking, as shown in FIG. As shown in FIG. 2, images of these areas are formed on the four groups of light receiving elements PL.

Each of the photodetecting elements f'PI, P6.8, U, P, +, and P+ receives the 1-th beam and outputs a photocurrent approximately proportional to the incident light beam. The upstream outputs of these lights are transmitted to the amplifier 12a,
12b, 12c and 12d each amplify the voltage, the first two are sent to the differential circuit 13°, and the latter two are sent to the differential circuit 13b.
, and the difference signals s5A and s5B are respectively detected.

Here, a set of two light receiving elements 7'P1. If the light intensity distribution of the image of the light beam of the tracking line tracking detection area Tb irradiated over P2 is equal to both, one light receiving element P1. The photoelectric output of P7 will be equal. Therefore, this difference signal B becomes O.

This means that within the tracking line tracking detection area Tb,
This is a case where the tracking line 4b is expected by aligning their center positions. The center of the tracking line tracking detection area Tb and the center of the toner/king line 4b are -
- If not, the photoelectric output of the photodetector 'fP+, P2 will not be 7, and a difference signal B corresponding to the difference will be output.

On the other hand, the image of the light beam of the trunking line tracking detection area T is projected onto the light receiving elements rPb and Pr. However, in the state shown in FIG. 5 of L2, the image of this light beam is significantly displaced and does not enter the light receiving element 7-P6. Therefore, the difference signal A corresponding to the displacement is output from the difference circuit j3a.

These difference signals A and B are sent to analog switches 14a and 1
46 and amplified by the amplifier 15. The amplified signal is output as a tracking error signal and can be used as a tracking error warning signal,
Used as a tracking error correction signal. For example, if the center of the tracking line tracking detection area Tb and the center of the tracking line 4b do not match, the difference between the output signals of the light receiving elements FP+ and P2 becomes large, and the difference signal B becomes large. A control mechanism that does not
The tracking error is corrected by moving the objective lens 11 so as to reduce this difference signal B.

Incidentally, which of the two data tracks Dd and Db in the same data recording area 3 is to read data from is determined according to a command from a control device (not shown). This command is a tracking A selection signal, tracking BI,!
! Output as selection signal.

Assuming that the tracking B selection signal is now being output, as shown in FIG. Reading is performed using the photodetector T-P3. P4 and P5 share the responsibility, but in this case, the photodetectors T-P4. P
It will be held at 5. However, if only reading is to be performed, one light receiving element f is sufficient, but in this embodiment, focusing control can also be performed.
Two elementary ts are used as one set. In addition, light reception, Nicho/P3. A configuration may also be adopted in which P4 and P5 are used exclusively for focusing, and reading is performed by another read-only light receiving element Y-.

On the other hand, when the trunking A selection signal 1) is output, the ]2 differential circuit 13. The difference Gj from Gj is outputted via amplifier l5. Here, when the optical system is in the state shown in FIG. 5, in the light receiving elements P6 and P+, since the image of the tracking line tracking detection area Ta is incident only on the light receiving element PI, a large A difference signal A is output. Therefore, a control mechanism (not shown) corrects the tracking error by moving the objective lens 11 of the optical system in accordance with this difference signal A. However, if the correction error is large, the optical system and the optical recording Correct by moving relative to the medium.

In this embodiment, when reading data from the data track Da, the light receiving elements are set to P3 and P4.

Second Embodiment> The tracking method of the second embodiment of the present invention shown in FIG.
L2 Similar to the first embodiment, this is an example of double-density recording, and is applied to S-number reading on the same optical recording medium as in the first embodiment.

In the tracking method of the second embodiment, the writing or reading action area WR is arranged at the center of the tracking line tracking detection areas Td, Tb, and the distance f is set between each data track and the nearest tracking line. The distance is set to be equal to the distance e. That is, f=e. Of course, the arrangement of each light-receiving element r in the light-receiving element f group for detecting these optical regions is also done accordingly.

Note that the other configurations and operations of this embodiment are the same as those of the L2 first embodiment.

Third Embodiment> The third embodiment of the present invention shown in FIGS. 8 and 9, respectively, is a modification of the L2 first and second embodiments, and has a write or read action area WR and a tracking line. Tracking detection area “ra”
, ``rb'' are set by dramatically extending the distance between them.The example shown in the 8th @ has the relationship f=2d-e, while the example shown in the 91st has the relationship f=d+e. Of course, there is a relationship.

The arrangement of each light-receiving element in the light-receiving element f group for detecting these optical regions is also done accordingly.

Note that the other configurations and functions of this embodiment are the same as the L2 first embodiment.

<Modifications of Embodiments> F2 In each of the embodiments, an example of double-density recording in which two data tracks are set in one data recording area is shown. It also enables high-density recording such as setting four data tracks in the data recording area of a book.

In addition, in each of the embodiments described above, an example was shown in which the detection areas for tracking line tracking were arranged at two locations, but for example, in order to cope with high-density recording, a configuration may be adopted in which the detection areas are arranged at an even larger number of locations. You can also do that.

Further, in each of the E2 embodiments, the write or read operation area is placed at an intermediate position equidistant from the two tracking line detection areas, but it is needless to say that this is not restrictive.

The relationship between f, d and e in each L2 example is as follows:
By converting this into a - film and including all the above examples, f=
It can be written as nd+e. Therefore, various features different from those of the L2 embodiments are available.

[Effects of the Invention] As explained above, the present invention can set a plurality of data tracks in one data recording area, can record data at high density, and can significantly increase recording capacity. Moreover, it can be realized without particularly requiring high precision, and has the effect of increasing the recording capacity easily and inexpensively.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams showing a first embodiment of the tracking method for writing and reading an optical recording medium of the present invention, and FIG. 3 shows an example of an optical recording medium to which the present invention is applied. FIG. 4 is an explanatory diagram showing an example of the optical system used to implement the tracking method of the present invention, and FIG. 5 is a photodetector T.
FIG. 6 is a circuit diagram showing an example of a tracking circuit used to implement the present invention, and FIGS. 7 to 9 are explanatory diagrams showing other embodiments of the present invention. . l... Optical recording medium 2... Recording area 3...
Data recording area 4... Tracking line 6... Light source 7... Collimating lens 8... Diffraction grating 9... Beam splitter 1) Ivy 10... Quarter wavelength plate 11... Objective lens 1
3a, 13b...Differential circuits 14a, 14b...Analog switch WR...Writing or reading action areas Td, Tb...Detection areas for tracking line tracking Da, Db...Data Track Applicant Computer Service Agent Co., Ltd. Patent Attorney Iwao Mishina Figure 1 Figure 2/D Figure 3 Figure 4! Fig. 6 Fig. 8 n Fig. 9 Teitokanshaso I (self-produced)

Claims (1)

[Claims] An optical recording medium for writing data in which a data track is set along the tracking lines in a band-shaped data recording area set between tracking lines arranged in parallel at regular intervals.
In the reading tracking method, at least two tracking line tracking detection areas, which are optical areas for detecting the tracking line and detecting its displacement, are lined up at a predetermined interval in the width direction of the data recording area. At the same time, a write or read action area, which is an optical area for writing or reading, is placed at an appropriate position from these tracking line tracking detection areas, and each tracking line tracking detection area and The positional relationship with the writing or reading area is such that when the tracking line tracking detection area located at any location is tracking the tracking line, the writing or reading area is located at the corresponding location in the data recording area. When the writing or reading area is located on one data track and another tracking line tracking detection area is tracking the tracking line, the writing or reading area is located on any other data track in the data recording area. A write/read tracking method for an optical recording medium characterized by setting as follows.