KR910008501B1 - Optical recording medium and tracking method therefor - Google Patents

Abstract

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Description

Optical recording medium and its tracking method

1 is a diagram showing the first embodiment of the optical recording medium of the present invention and an explanatory diagram showing the tracking method of the second embodiment of the present invention.

2 is a plan view showing a first embodiment of an optical recording medium of the present invention.

3 is an explanatory diagram showing an example of an optical system used for carrying out the tracking method of the optical recording medium of the present invention.

4 is an explanatory diagram showing an example of a light receiving element group of the present invention.

5 is a circuit diagram showing an example of a tracking circuit used in the embodiment of the second embodiment of the present invention.

6 to 9 are explanatory views showing the third to fifth embodiments of the present invention, respectively.

10 and 11 are explanatory views showing a sixth embodiment of the tracking method for writing / reading by the optical recording medium of the present invention.

12 is an explanatory diagram showing an example of a light receiving element group of the present invention.

FIG. 13 is a circuit diagram showing an example of a tracking circuit used in the sixth embodiment of the present invention. FIG.

14 is an explanatory diagram showing a seventh embodiment of the present invention.

15 and 16 are explanatory views showing the eighth embodiment of the present invention.

FIG. 17 is an explanatory diagram showing a ninth embodiment of the optical recording medium of the present invention; FIG.

18 is an explanatory diagram showing an example of a light receiving element used in the ninth embodiment.

19 is a circuit diagram showing an example of a tracking circuit used in the embodiment of the ninth embodiment.

* Explanation of symbols for the main parts of the drawings

1: optical recording medium 2: recording area

3: data recording area 4: tracking line

4a, 4b: Edge 5: Each point

6: light source 7: collimated rent

8 diffraction grating 9 beam splitter

10 wavelength wave 11: objective lens

12a, 12b, 12c, 12d: amplifier 13: differential circuit

13a, 13b: differential circuit 15: amplifier

14a, 14b: analog switch 16: switch

17: comparison circuit 18a, 18b: reference power

D _a , D _b : Data track O: Centerline

e: shift d: pitch

D _a1 , D _a2 , D _a3 , D _b1 , D _b2 , D _b3 : Attachment number T: Tracking detection spot

T _a , T _b : Tracking detection spot WR: Write / Read spot

WR _a , WR _b , WR _c : write / read molten spot

P: light receiving element group f: distance

P ₁ , P ₆ : a plurality of light receiving elements g: distance from the center

M: Write / Read Spot S: Track Detection Spot

The present invention relates to an optical recording medium in which a track is set along a tracking line in a data recording area formed in a band shape across a tracking line, and data for each of a plurality of these data tracks. It is about tracking method when writing or reading.

The optical recording medium that has been developed in recent years is characterized by a very large recording capacity as compared with the conventional magnetic recording medium.

This can only record data at a high density in a small area.

When recording and reproducing data with high density for such a small area, it is necessary to accurately track the data recording or writing / reading element in which data tracks are recorded.

Conventionally, as a means for this, there is a method of setting a data track in the center of a band-shaped data recording area set between the tracking lines formed side by side at regular intervals.

This method is a structure that writes or reads data while tracking two tracking lines between recording areas, so that high density write / read is possible.

By the way, in the conventional method described above, one data track is formed in one band-shaped data recording area, so that the entire recording area of the optical recording medium is alternately arranged with the data track and tracking line. Therefore, in such a conventional system, there is a problem that the data recording capacity decreases as much as the tracking line exists.

In contrast, it is conceivable to increase the data recording capacity and to narrow the interval of the tracking lines.

However, in narrowing the space | interval of a tracking line, there exist technical limitations, such as refinement | miniaturization of the pattern line of a tracking line at the time of a medium manufacture, and it is difficult to implement | achieve.

It is an object of the present invention to provide an optical recording medium capable of recording data at a high density by setting a plurality of data tracks in one data recording area, and greatly increasing the recording capacity. Another object of the present invention is to provide a tracking method in which an optical recording medium having a plurality of data tracks set in one data recording area can write or read data with high accuracy for each data track. It's there.

The present invention provides an optical recording medium in which data tracks are set along a tracking line in a data recording area on an optical recording medium to write or read data, and the band-shaped data interposed between the tracking lines. The data track is set in the recording area at a position shifted from the center of the width direction of the data recording area.

In addition, the present invention provides an optical recording medium as a tracking method when writing or reading data to and from an optical recording medium having a format for setting a data track along a tracking line in one data recording area as described above. An optical area for tracking the tracking line by moving the position relative to the medium, and an optical area for writing or reading by moving in association with the optical area for tracking the tracking line, on the optical recording medium. Setting the positional relationship between these areas on a data track where the optical area for writing / reading is shifted from the center of the width direction of the data recording area when the tracking optical area tracks the tracking line. It is characterized by setting to move.

In the optical recording medium of the present invention, at least one data track is formed at a position shifted from the center of the width direction of the data recording area. The positions at which the data tracks are formed are determined so as not to overlap each other when there are a plurality of data tracks to be set. This position is set in consideration of conditions such as the width of the data recording area, the width of the data track, and the number of data tracks to be set. In the case of forming a plurality of data tracks, one of them may be arranged at the center of the width direction of the data area.

Further, in the tracking method of the present invention, the optical region for tracking the tracking line is made of an optical spot formed by projecting onto a optical recording medium through an optical system a light beam such as a laser beam. The reflected light of the tracking optical area is incident on an element that tracks and detects through an optical system to detect a tracking control signal and use it for tracking control.

The optical area for writing or reading out is also made of an optical spot formed by projecting a light beam such as a laser beam onto an optical recording medium through an optical system, similarly to the tracking optical area.

In the case of writing, the optical change pattern is formed at the data track setting position of the data recording area by the optical energy supplied to this optical spot.

In addition, in the case of reading, the reflection intensity of the optical spot by the optical change pattern formed at the data track setting position is detected and the written signal is read out.

When the data recording area is illuminated as a whole, the tracking optical area and the optical area for reading out may be set as the field of view on the data recording area of the detection element without irradiating light beams.

In the tracking method according to the present invention, the distance between the optical area for tracking the tracking line and the optical area for writing or reading is set in a predetermined positional relationship.

That is, in the present invention, since a plurality of data tracks are set in one data recording area, it is necessary to selectively position the optical area for writing or reading out on another data track in the same data recording area.

Various forms are possible as a form for this.

For example, by forming a plurality of tracking optical areas having different positional relations with respect to the optical area for writing or reading out, and selecting either of them to track the tracking line, It is conceivable to selectively position the region on the corresponding data track.

Further, for example, the two optical regions can be configured to be used in either the tracking optical region or the writing or reading optical region, and the positions of the two positions can be changed by changing the functions of both sides, so that the different positions can be used. It is conceivable to correspond to the data tracks in the system.

Depending on the tracking line, various forms are conceivable. That is, the tracking of the tracking line is considered to be based on the center of the width direction of the tracking line and on the basis of the edge of the tracking line.

The tracking method of the present invention can be applied in either case.

In addition, as a preferable aspect in this invention, although the tracking line which adjoins to the data recording area | region where the data track which should be written or read-out is located is referred, it is also possible to refer to the tracking line which is not adjacent. According to the present invention, the data track is set in one data recording area at a position shifted from the center of the width direction of the data recording area, so that a plurality of data tracks can be set in one data recording area, so that high density recording can be achieved. It becomes possible.

In the tracking method of the present invention, the optical area for tracking line tracking and the optical area for writing / reading move in association.

In addition, when the optical area for tracking and the optical area for writing / reading have a constant positional relationship, that is, when the optical area for tracking is tracking the tracking line, the optical area for writing / reading is the width direction of the data recording area. Since it is arranged to move on the line at a position shifted from the center of, the data track to be written or read is selected by setting the tracking line to be tracked. For this reason, for example, by tracking the optical area for tracking line tracking with respect to the center or edge of the tracking line, the optical area for writing / reading tracks the data track according to the positional relationship.

Therefore, in the present invention, when data tracks are set at positions substantially symmetrically shifted on both sides of the center line through the center in the width direction of the data recording area, an even number of even data tracks are formed in one data recording area. A double density optical recording medium can be realized.

The most representative one is a double density format in which two data tracks are formed in one data recording area.

However, at least one data track may be set in one data recording area.

Further, the present invention can form data tracks even in the center of the width direction of the data recording area, and even in this case, it is possible to realize odd-density recording in which three or more odd data tracks are formed.

The most representative one is a triple density format in which three data tracks are formed in one data recording area.

As described above, according to the present invention, an optical recording medium capable of setting a plurality of data tracks in one data recording area, recording data at a high density, and significantly increasing the recording capacity, and a tracking method thereof. Can be realized.

In addition, the present invention can be realized without requiring particularly high precision, and the recording capacity can be increased easily and at low cost.

EXAMPLE

An embodiment of the present invention will be described in detail with reference to the accompanying drawings. First, in the drawing, the tracking detection spots T are the respective tracking detection spots T _a , (T _b ). Bet to the accompanying Souza that need to be identified as representative represents sseoneotgi / reading, such as a spot (WR) is bet sseoneotgi / read spot, respectively _{(WE a), (WR b} ) ... Representative numbers of attachments that need to be identified as In addition, although the tracking method shown in the following Example is an example applied to the apparatus provided with both functions of writing and reading, it can also apply to the apparatus of writing only or reading only.

Example 1

1 and 2 show the structure of an optical recording medium which is the first embodiment of the present invention. The optical recording medium 1 forms a recording area 2 on which a recording medium is formed on a card-shaped substrate, and in this recording area 2, a band-shaped tracking line 4 is defined. A plurality of bands are arranged at intervals and interposed between these tracking lines 4 as the data recording area 3. The embodiment of the present invention is an example of performing double density recording by setting two data tracks (D _a ) and (D _b ) for each data recording area 3. The data tracks (D _a ) and (D _b ) are formed at positions substantially symmetrically shifted on both sides of the center line O through the center of the width direction of the data recording area 3 together. That is, it is arrange | positioned at the position shifted by (e) from the center O of the width direction of the data recording area 3.

In the case of the embodiment of the present invention, this shift (e) is set such that 2e becomes slightly smaller than d / 3 when the pitch of the tracking line 4 is taken as (d).

In the embodiment of the present invention, the configuration is as described above, and the data tracks (D _a ) and (D _b ) are arranged at intervals of 2e.

Further, it is placed in the data track (D _a) and (D _b), based on the center line of the track (4) which are adjacent respectively, (d / 2) is spaced apart by -e position. In addition, the formation positions of the data tracks (D _a ) and (D _b ) can be set even with reference to both energy 4a and 4b of the tracking line 4, respectively.

Incidentally, in FIG. 1 (hereinafter also the same in other drawings), the data tracks D _a and D _b are formed for each data recording area 3, and for convenience of explanation, either of them is a data recording area. When it is necessary to identify whether or not the data track is a data track, the number of appended numbers should be given as in (D _a1 ), (D _b1 ), (D _a1 ) and (D _b1 ).

Therefore, at least one data track is set in a band-shaped data recording area 3 sandwiched between the tracking lines 4 at a position shifted from the center of the width direction of the data recording area 3, It is also possible to form at least two data tracks (D _a ) and (D _b ) in one data recording area 3. At this time, the data tracks are formed (D _a), (D _b) sets the data tracks (D _a), (D _b) in a symmetrically shifted from the center in the width direction of the data recording area 3 position.

In addition, the black and rounded columns of each data track indicate a state in which data is written, while for the data tracks in which data is not written, the position is indicated by a virtual line for convenience of explanation.

Thus, an optical area formed to track the tracking line 4 by moving on the optical recording medium 1 relative to the medium 1, and moving and writing in association with the optical area for tracking line tracking. An optical area for reading out is formed on the optical recording medium 1. Then, when the tracking optical area tracks the tracking line 4, the positional relationship of the area is upward from the position where the optical area for writing / reading is shifted from the center of the width direction of the data recording area 3. Data tracks (D _a ) and (D _b ) are formed to move to.

1 and 2 show the configuration of the tracking method of the optical recording medium which is the first embodiment of the present invention.

The embodiment of the present invention is an example of a tracking method applied to the optical recording medium having the form shown in the first embodiment. According to an embodiment of the present invention, an optical spot (hereinafter referred to as a tracking detection spot) T corresponding to an optical region for tracking a tracking line and an optical spot corresponding to an optical region for writing or reading out (hereinafter referred to as writing / When the former tracks the tracking line 4, the latter is located at a position shifted from the center O in the width direction of the data recording area 3 by (e). It is arrange | positioned so that it may be located on track D _a or D _b . As a result, the tracking detection spot T and the write / read spot WR in FIG. 1 are arranged at intervals of (d / 2) -e.

1 shows two modes at the time of tracking. The numerals in the sign indicate the mode.

The above interval corresponds to the distance at the center of each of the adjacent tracking lines 4 of the data tracks (D _a ) and (D _b ) described in FIG. 2, and therefore, the optical recording of the present invention. The tracking method of the medium is a process of tracking optical domains arranged in parallel at a predetermined interval in at least two places in the width direction of the data recording area 3, and an optical area for writing / reading in the tracking optical area tracking process. And a process of tracing the tracking line 4 by the tracking optical area at either place in consideration of the positional relationship between the optical area for writing / reading and each tracking optical area. and corresponding to any one of the data tracks (D _a), (D _b) to be located above the optical zone for different track to the track of the tracking line 4 in the optical area, the data recording area 3 And this takes place in sseoneotgi / readout optical zone is a data recording area (3) in the process of any one of the other data tracks so as to be positioned over _(a D), (D _b).

And a step of projecting a light beam onto the optical recording medium 1 formed as a light spot through the optical system, respectively, for the tracking optical region and the writing / reading optical region, wherein the tracking line 4 The process of tracking the data tracks (D _a ), (D _b ) with respect to the slightly inner side of the edges 4a (4b) along the data tracks (D _a ), (D _b ), is included.

That is, when the tracking detection spots Ta, Tb, the writing / reading spot WR, and the data recording area 3 are parallel to the width direction, and the former is positioned on the tracking line 4, The line through the point where the latter is located is coincident with the data track D _a or D _b .

In the case of the embodiment of the present invention, two light spots are allocated to the tracking detection spot T and the write / read spot WR. This assignment is fixed, and the positional relationship between the optical spots for tracking detection and writing / reading is reversed and used for tracking other data tracks.

The tracking detection spot T and the write / read spot WR are formed, for example, as light domains as shown in FIG.

That is, the optical system shown in FIG. 3 includes a light source 6 such as a semiconductor laser, a collimating lens 7 having light emitted from the light source as a parallel beam, and a diffraction grating 8 that divides the light beam into a plurality of beams. ), A beam splitter 9 for separating transmitted light and reflected light, a quarter wave plate 10 for orthogonalizing the polarization plane of incident light and reflected light to the optical recording medium, and an objective lens 11 do.

This optical system can be used for both writing and reading. At the time of writing, by increasing the output energy of the light source 6, by irradiating the light beam spot of strong energy to the data recording area, and applying the part locally or by changing the reflectance by blackening the data, You can write

On the other hand, at the time of 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, for example, formed by the presence or absence of the point 5, and written.

The diffraction grating 8 diffracts the light beam to form a light beam consisting of a plurality of beams separated at predetermined intervals.

That is, by using the optical system common to tracking, the data can be written by forming a pattern of optical change at the data track setting position of the data recording area 3 by the light energy supplied to the writing optical area. .

At this time, by using the optical system common to tracking, the signal which detects the reflection intensity by the pattern language of the optical change formed in the data track setting position from the reflected light of the optical area for reading out is read out, and the signal which is written is read out, When the area tracks the tracking line 4, a corresponding data track of data tracks (D _a ) and (D _b ) in which _a plurality of write / read optical areas are set in the data recording area (3). You can move up.

In the embodiment of the present invention, the main beam is subtracted from the plurality of separated optical beams by a mask (not shown), and the main beam is written or read as the subbeam beam for tracking line tracking. We use bet beam. The arrangement relationship of these beams corresponds to the above-described writing / reading spot WR and the mainline detection spot T. FIG. That is, in the embodiment of the present invention, their beams form a write / read spot WR and a tracking detection spot T.

In addition, the same is true for the following embodiments, but by changing the diffraction grating 8, the interval between the beams can be changed, and correspondingly, the writing / reading spot WR and the tracking detection spot T are correspondingly made. You can change your relationship with In the embodiment of the present invention, behind the diffraction grating 8 is placed a beam position rotating element (not shown) which rotates the spatial arrangement of the main beam and the sub-beam 180 degrees around the sub-beam. Subtraction is placed freely.

This element is formed, for example, as optical irradiation of a lens system, a prism, or the like. In the state where the element is not inserted into the optical path, the main beam and the sub beam are projected onto the optical recording medium in the positional relationship as they are, for example, in the form of the B mode shown in FIG. Form a reading spot (WRb) (main frame) and a tracking detection spot (T _b ) (subframe).

On the other hand, when the rotating element of the beam position is inserted into the optical path, the main beam and the sub beam are projected onto the optical recording medium in a state where the positional relationship is rotated by 180 degrees around the latter, for example, the first Each spot WR _a , T _a is formed in the form of the A mode shown in the figure.

The light-receiving element group P is formed together with the optical system, and receives the beam of light drawn out of the scientific system as the beam splitter 9 to track and read the tracking line and perform a function as a sensor. The light receiving element group R is formed of a semiconductor light receiving element such as a pin (PIN) photodiode. For example, as illustrated in FIG. 4, the plurality of elements P _{1 to} P ₆ are arrayed. Are arranged in a shape.

In the embodiment of the present invention, two sets of elements P ₁ and P and two sets of elements P ₅ and P ₆ are read out, and the elements P ₃ and ( P ₄ ) is for tracking line tracking.

In addition, even though there is only one write / read spot WR, two sets of read-out light receiving elements are prepared when the data is written to the data tracks above and below the tracking line 4. The purpose is to insert the beam position rotating element into the optical path so as to rotate the positional relationship between the writing / reading spot WR and the tracking detection port T by 180 degrees.

Therefore, when the positional relationship of the light beams is not rotated by 180 degrees by this element, the light receiving element for reading is good as one set. For this reason, in the embodiment of the present invention, the light receiving element for tracking line tracking is used as the tracking tracking circuit at the output of the light receiving elements P ₃ and P ₄ as the tracking tracking circuit, respectively. And 12b are connected to the differential circuit 13.

On the other hand, two sets of elements P ₁ and P ₂ and one set of elements P ₅ and P ₆ are connected to a readout circuit (not shown). In addition, when the mode is changed by changing the positional relationship between the sub-beam and the main beam by the method described later, two sets of light-receiving elements can be employed.

In this case, one side is configured to switch alternately for tracking and the other for reading.

As described above, in the embodiment of the present invention, since there are two light spots, data writing becomes two modes, A and B.

For example, in the mode A, in FIG. 1, when the tracking detection spot T _a is on the tracking line 4, the other write / read spot WR _a is located in the data recording area 3. It corresponds to the data track (D _a).

In addition, in the B mode, when one light spot has the tracking detection spot T _b on the tracking line 4, the other writing / reading spot W _b shows the data of the data recording area 3 ( D _b ).

The relationship between the A mode and the B mode is that the write / read spot WR is rotated 180 degrees around the tracking detection spot T.

That is, as shown in FIG. 1, the arrangement of the spots T and WR is inverted up and down. In the embodiment of the present invention, the B mode is a normal arrangement, and the A mode is a rotating image.

As described above, the write / read spot WR and the tracking detection spot T match the positions of the data tracks to which the write / read spot WR is to be written. Or the entire optical system, including the light-receiving element group, so that the reflected light moves on the element group P in the side-by-side direction.

That is, in the invention example, by a moving element (P ₃₎ and (P ₄₎ perimeter and, in this element (P ₃₎ and (P ₄₎ on the tracking line formed by the reflection images (像) ( in 4) a modal on this when coincident center lines of elements (P ₁₎ and the target data track formed by the reflection images on the boundary line and a device (P ₁₎ and (P ₂₎ with (P ₂₎ (D _a) The center lines are arranged to approximately coincide with each other.

On the other hand, B Modal in is arranged the central line of the element (P ₅₎ and the boundary line and a device (P ₅₎ and (P ₆₎ the data track (D _b) formed by the reflected image over the (P ₆₎ so as to substantially coincide .

When the light receiving elements P ₃ and P ₄ are captured in a state where the center of the tracking line 4 is not shifted in the field of view, the amount of light received by the adjacent elements is large and the distribution of brightness is increased. Is approximately equal between the elements.

On the other hand, when the tracking line is biased to a part of the visual field, the light receiving amount is small and the tracking line is tracked using this property.

Next, the tracking operation according to the embodiment of the present invention will be described with reference to the respective drawings described above, taking the case of writing data as an example. Also in the case of reading, the tracking action is the same as in the case of writing. Now, in the recording area 2, it is assumed that data is written into an arbitrary data recording area 3. In the optical system, the light from the light source 6 is divided into four beams through the collimating lens 7 and the diffraction grating 8, respectively, the beam splitter 9, the quarter wave plate 10, and The optical recording medium 1 is irradiated through the objective lens 11.

At this time, the two light beams form a tracking detection spot T and a write / read spot WR on the optical recording medium 1. Here, the reflected light is returned to the beam splitter 9 via the objective lens 11 and the quarter wave plate 10.

By the way, each beam transmits reciprocally through the quarter wave plate 10, and since the polarization plane rotates 90 degrees compared with the light from the light source 6, the beam splitter 9 ) Is reflected and emitted to the outside of the optical system.

The emitted light from the tracking detection spot T and the write / read spot WR is input to the light receiving element group P, and as shown in FIG. 4, these spots are placed on the light receiving element group P. As shown in FIG. Form the phase of. That is, in the case of the A mode, the spots T _a and (WR _a ) are formed, and in the case of the B mode, the spots T _b and (WR _b ) are formed. Each of the light receiving elements P ₄ and P ₃ and P ₆ and P ₅ receives the beam and outputs a photocurrent approximately proportional to the amount of incident light. Each of the light receiving elements P ₄ , P ₃ and (P ₆ , P ₅ ) or (P ₂ , P ₁ ) receives the beam and outputs a photocurrent approximately proportional to the amount of incident light. The photocurrent outputs of the light receiving elements P ₄ and P ₃ are voltage amplified as the amplifiers 12a and 12b, respectively, and input to the differential circuit 13 so that a difference signal is detected. Here, the light non-critical light quantity distribution of the tracking detection spot T irradiated over two light receiving elements P ₃ and P ₄ which are two sets is on both sides.

As a result, this difference signal becomes zero. This is a case where the tracking line 4 is expected by matching the center position thereof in the tracking detection spot T. In the case where the center of the tracking detection spot T and the center of the tracking line 4 do not coincide, the photoelectric outputs of the light receiving elements P ₃ and P ₄ are not the same, but the difference signal according to the difference Is output.

The difference signal is amplified as an amplifier (not shown), output as a tracking error signal, used as a tracking error warning signal, or used as a tracking error correction signal. For example, when the center of the tracking detection spot T does not coincide with the center of the tracking line 4, the difference between the output signals of the light receiving elements P ₃ and P ₄ becomes large, and the difference signal Is increased so that the tracking line is corrected by moving the objective lens 11 so as to reduce this difference signal by a control function (not shown).

However, when the amount of correction is large, the optical recording medium of the optical system is moved in a square direction and corrected. By the way, if writing is performed by the mode B now, if the tracking is normal, the writing / reading spot WR (hereinafter referred to as WR _b in this mode) is the target date tracking (D _6). ) In this case, when the output of the light beam is increased, the specific position of the data track is checked as the light beam writing / reading spot WR _b . As a result, this beam irradiation portion is locally formed to be melted or blackened, and the optical state of the reflectances is formed as a shape of the writing / reading spot WR _{b in which} the optical state is different from other portions. This optical state becomes point 5, and records data as a digital value.

In the case of the embodiment of the present invention, writing of data is performed by moving the optical recording medium relatively in the direction indicated by the arrow in FIG. 1 by a driving device (not shown).

When it reaches to the next writing position of the point 5 by such a movement, the irradiation intensity of a light beam is strengthened and it writes in the part. In this manner, as shown in FIG. 1, data is written sequentially in accordance with the write data.

However, it is good also as a structure which moves to the next writing point after stopping and writing once at the time of writing. Immediately after this writing, as shown in FIG. 4, the data written to the data track D _b by the light receiving elements P ₅ and P ₆ is read out, and the data is written with the writing data. It can be used for comparison checking to check for errors during writing.

Next, when the beam position rotating element (not shown) is inserted between the diffraction grating 8 and the beam splitter 9 and moved from the mode B to the mode A, as shown in FIG. The positions of the writing and reading spots WR are inverted up and down with respect to the tracking detection spots T.

As a result, the write / read spot WR (hereinafter, denoted as WR _a in both cases) is the data track D _a of the data recording area 3 located next to the data recording area 3. )

Further, so taking the light-receiving element (P _1), to read the data in the data tracks (D _a) by (P ₂₎ as described above, is used to check for errors in sseoneotgi.

Here, in the light receiving element group, two elements are used in pairs for the light receiving elements P ₁ , P ₂ , P ₅ , and P ₆ . Although it is satisfied that there is one light receiving element, in the embodiment of the present invention, the focusing control can also be performed.

The light receiving elements P ₁ , P ₂ , P ₅ , and P ₆ may be dedicated to focusing, and the reading may be performed by a separate read-only light receiving element. When writing to the data track is finished, the optical system and the optical recording medium are moved relatively in the width direction of the data recording area, and the tracking detection spot T (T _b / T _a ) is moved to the next tracking line 4. Set to the position of.

Further, in the embodiment of the present invention, the mode A and the mode B write data from one mode to the entire data recording area, and then write data of the other mode, one data recording area. It is possible to write data in both modes alternately every time, and to write data in both modes alternately at each point 5 of one data recording area.

In this way, data of all data tracks can be written by sequentially writing data along the tracking line.

In this case, it is also possible to perform random access by means such as counting the number of tracking lines. In the embodiment of the present invention, when reading data, the irradiation is performed by irradiating light beams with reduced output so that the beam irradiating portion is not locally melted.

In the embodiment of the present invention, the positional relationship between the main beam and the sub-beam is limited by setting the position of the main beam rotated by 180 degrees around the sub-beam, but the change of the positional relationship between the two beams is different means. You may carry out as.

As another example of the changing means, for example, it is conceivable to use an inverter element which inverts the intensity ratio of the light energy of the main beam and the sub beam.

In this case, two light receiving elements are sufficient.

In addition, as other changing means, it is conceivable to use the same beam position rotating element as in the above embodiment to rotate the main and sub-beams by 180 degrees around the intermediate position on both sides, thereby changing their positions. . In this case, the light receiving element is sufficient as two sets.

Example 2

6 and 7 show a second embodiment of the data tracking method of the optical recording medium of the present invention. In the present embodiment, as in the first embodiment, double density recording is performed on an optical recording medium having two data tracks (D _a ) and (D _b ) set for each data recording area 3. Is an example of a tracking method.

In the present embodiment, the tracking detection spot T and the write / read spot WR are the centers of the width direction O of the data recording area 3 when the former tracks the tracking 4. ) To place the data in a position shifted by (e).

Here, two write / read spots, WR _a and WR _b , are formed symmetrically around the tracking detection spot T. The write / read spots WR _a and WR _b need not be formed at the same time. One tracking detection spot T and two writing / reading spots WR _a and WR _b interposed therebetween are spaced at a distance f.

In the case of this embodiment, the two write / read spots WR _a and WR _b are not in the data track adjacent to the tracking line 4 tracked by the tracking detection spot T.

로 된다.It is arranged to be located on the outer data track thereof. Here, the distance f is the above positional relation when the distance at the center of the trekking lines 4 and 4 sandwiching the data recording area 3 is d.

It becomes

These tracking detection spots T and the write / read spots WR _a and WR _b are configured as optical systems in which a light source made of a semiconductor laser is added to the optical system shown in FIG. That is, the light spot is formed by superimposing the light beams from the added light source on the plurality of light beams on which the diffraction grating 8 is formed, forming two main beams and one sub-beam.

In the three light beams configured as described above, the center beam is the tracking line tracking beam, and the main beams on both sides are the beam for writing or reading. The arrangement of these beams corresponds to the above-described write / read spots WR _a and WR _b and tracking detection spots T.

In other words, in this embodiment, these beams form the writing / reading spots WR _a and WR _b and the tracking detection spot T on the optical recording medium.

In addition, the light-receiving element group P formed attached to the optical system of this embodiment is comprised as an array as shown in FIG. The arrangement pitches of the light receiving element bands P _1, P ₂ , P ₃ , P ₄ , and P ₅ , P ₆ are set in accordance with the positions of the reflection images of the respective spots. Two sets of elements P ₁ and (P ₂ ) and two sets of elements P ₅ and ( _, P ₆ ) are for reading, and elements P ₃ and (P ₄ ) Two sets of are used for tracking line tracking.

The write / read spots (WR _a ), (WR _b ) and the trace detection spot (T) correspond to two data tracks (D _a ) and (D _b ) for the write / read spots (WR _a ) and (WR _b ). ), The objective lens 11 is moved to move in the side-by-side direction of the element group P.

That is, in the present embodiment, when the boundary lines of the elements P ₃ and P ₄ coincide with the center line of the tracking line ₄ by this movement, the elements P ₁ and ( _, P ₂ ) between the boundary line and on the center line of the track date (D _b), in addition, the element (P ₅₎ and _(, it is arranged so that over the center line of the boundary track data (D _a) of the P _6).

Next, the operation of data writing according to the present embodiment will be described with reference to the respective drawings, centering on points that differ from the first embodiment.

Also, in the case of readout, all of the write operations are the same as in the case of writing. Now, in the recording area 2, it is assumed that data is written into an arbitrary data recording area 3. In the light system, the light from the light source 6 is divided into three beams via the collimating lens 7 and the diffraction grating 8, and the light beams from the added light source are superimposed, respectively. 9), the quarter wave plate 10 and the objective lens 11 are irradiated to the optical recording medium 1. At this time, the three light beams form the tracking detection spot T and the write / read spots WR _a and WR _{b on the} optical recording medium 1. Here, the reflected light is returned to the beam splitter 9 via the objective lens 11 and the wave plate 10 for four minutes.

The emitted light at the tracking detection spot T and the write / read spots WR _a and WR _b is incident on the light receiving element group P, and is the same as in the case of the first embodiment. As shown in the figure, the image of these spots is formed on the light receiving element group P. As shown in FIG. Each of the light receiving elements P ₆ , P ₅ , P ₄ , P ₃ , and P ₂ , P ₁ receives the beam and outputs a photoelectric source approximately in proportion to the incident light egg. The photocurrent outputs of the light receiving elements P ₃ and P ₄ are used for tracking detection in the same manner as in the case of the second embodiment. By the way, whether data is written by two write / read spots WR _a or WR _b depends on a command from a control device (not shown). If the selection signal for selecting the write / read spot WR _b on the data track D _a1 is outputted now, the data track D _a2 write / read spot is provided by light blocking means (not shown). The light beams forming WR _b are cut off, the light beams with increased output are irradiated, and the beam irradiation part is locally melted and data is written.

In the case of this embodiment, the data is written one by one, but in this case, the optical recording medium moves relatively in the direction indicated by the arrow in FIG. 6, and as shown in FIG. The data is written sequentially. At this time, as shown in FIG. 4, the data written to the data track D _a1 is read out by the light receiving elements P ₅ and P ₆ and compared with the write data. This can be used to check for errors in writing.

On the other hand, when the selection signal for selecting the data track D ₆ is outputted, the write beam is cut off by blocking the light beam forming the write / read spot WR _b on the data track D _a1 .

In the above, similarly, the data of the data track D _b2 is read by the light-receiving receivers P ₁ and P ₂ and used for checking an error during writing.

The writing of the data to the data tracks D _a1 and D _b2 is performed after the writing of one data is completed and the method of writing the data on the other side, while also writing on both sides of the data tracks D _b1 and (D _b2 ). _b2 ) may be any of the methods using the above.

In this manner, writing to the data tracks D _a1 and D _b2 is performed on the write / read spot WR _b . (Refer to the state of FIG. 6) When writing is completed as the data track, the optical system and the optical The recording medium is moved relative to the width direction of the data recording area, and as shown in FIG. 7, the tracking detection spot T is set at the position of the next tracking line 4.

Here, if tracking is checked in the same manner as above, data is written. This writes data to the data tracks D _a2 and D _b3 .

In this way, data of all data tracks can be written by sequentially writing data along the tracking line.

In this embodiment, it is also possible to write data simultaneously on both sides of the data tracks D _a and D _b .

In addition, in the present embodiment, the write / read spots WR ₂ and WR ₆ are formed in bell, but the tracking detection spot T and the write / read spot WR are set one by one. As in the case of the first embodiment, a configuration in which the light beam is tilted and written by the objective lens may be used.

Example 3

로 되도록 설정한 예이다. 이에 따라서, 본 실시예는, 수광소자군(P)의 각 소자의 배치 간격이 변경된다.The data writing method of the third embodiment of the present invention shown in FIG. 8 is applied to the optical recording medium shown in the first embodiment as an example of performing double density recording in the same manner as in the second embodiment. The data writing method of this fourth embodiment is such that the write / read spots WR _a and WR _b correspond to data tracks immediately adjacent to the tracking line 4, so that the write detection spot T and the write-in spot are written. / Spacing (f) with reading spot (WR _a ), (WR _b ),

This example is set to Accordingly, in the present embodiment, the arrangement intervals of the elements of the light receiving element group P are changed.

In addition, other components and functions are the same as those of the second embodiment.

Example 4

The fourth embodiment of the present invention shown in FIG. 9 is an example in which three data tracks (D _a ), (D _b ) and (D _c ) are set in the data recording area unlike the respective embodiments described above. . In other words, the optical recording medium of this embodiment, three data tracks _{(D a), (D b} ) , and (D _c) in the,, (D _a) to (D _d) at the center in the width direction of the data recording area, And (D _c ) in a position symmetrically shifted from the center by (e).

Writing and reading out of the optical recording medium configured as described above are performed by forming a tracking detection spot T and three writing / reading spots WR _a , WR _b , and WR _c .

In this case, of the three writing light spots, the position where (WR _b ) is symmetrically shifted (e) from the center by (WR _a ) and (WR _c ) from the center of the width direction of the data recording area. To put the data in.

In this embodiment, the optical system is the same as that of the second embodiment except that the four light beams are formed and four sets of light receiving elements are arranged correspondingly. The three writing light spots WR _a , WR _b , and WR _c are selectively formed corresponding to the data tracks to be written. This selection is made by writing data in one write spot for the entire data recording area, and then sequentially writing data in another write spot for the same data, alternating three data in each data recording area. sseoneotgi light spot for (WR _a), (WR _b), (WR _c) betting method for performing sseoneotgi of data, three sseoneotgi / read alternately for each of the point 5 of the first data recording area on the spot (WR _a ), (WR _b ) and (WR _c ) can be used to write data.

The write / read spots WR _a , WR _b , and WR _c can be easily realized as a predetermined positional relationship by changing the diffraction gratings by changing the diffraction gratings.

The write / read spots WR _b and WR _c may be superimposed with a plurality of light sources.

Example 5

10 and 11 show a fifth embodiment of the tracking method of the optical recording medium of the present invention.

This embodiment is applied to the optical recording medium 1 of the type shown in FIG. That is, for each data recording area 3, the tracking method for the optical recording medium 1 in which two data tracks D _a and D _b are set at positions shifted from the center in the width direction thereof. Is an example. In the tracking method of this embodiment, as shown in these figures, two tracking line tracking detection spots T _a and T _b are arranged so as to be parallel to each other in the width direction of the data recording area 3 at predetermined intervals. At the same time, _a write / read spot WR _b is disposed at an appropriate position (intermediate in this embodiment) between these tracking detection spots T _a and T _b .

In the present embodiment, the interval between the write / read spot WR and two tracking detection spots T _a and T _b sandwiching them is determined by the tracking detection spots T _a and T. _b ), when one of the tracks (T _{a in} FIG. 10) tracks the tracking line 4, this write / read spot WR is located on one data track (FIG. 10 in the data recording area 3). Is located above D _a ) and when this tracking detection spot (WR) on the other side is tracking the tracking line 4 (see FIG. 11), this write / read spot (WR) is the data recording area (3). It is set so as to be positioned on the other data track (D _{b in} FIG. 11).

Than the tracking detection spot _{(T a), (T b} ) and, sseoneotgi / readout spot (WR), for example, it is formed as an optical system as shown in the third degree.

In this embodiment, a plurality of beams separated as the diffraction gratings 8 are beams for writing or reading out a central beam, and beams for tracking line tracking are provided on both sides thereof. The arrangement of the beam corresponds with the above-mentioned figure sseoneotgi / read spot (WR) and a tracking detection spot _{(T a), (T b} ).

Here, the write / read spot WR and the trace detection spots T _a and T _b are adjacent to the data tracks D _a and D _b , as shown in FIG. 10. The distance from the center of the tracking line 4 to g, and the interval of the tracking line 4 is d, and the distance between the tracking detection spots T _a and T _b and the write / read spot WR. When f is each, there is a relationship of f = dg between them.

The light receiving element group P is formed together with the optical system, and serves as a beam splitter 9 as a sensor for tracking and reading out of the optical system.

The light receiving element group (P) is made of a semiconductor light-receiving element such as a pin photodiode, in the present embodiment, as shown in the Figure 12, by placing a plurality of elements (P ₁ ~P ₆₎ in an array-like It is composed. Here, _{one pair} of two elements P ₁ and P ₂ and _{one pair} of two elements P ₅ and P ₆ are used for tracking line tracking, and electrons are detected from the detection area T _a . The latter corresponds to the detection area T _b .

In addition, the elements P ₃ and P ₄ are for reading.

The above-described write / read spot (WR) and tracking detection support (T _a ) and (T _b ) have either a write / read spot (WR) of two data tracks (D _a ) or (D _b ). In this case, either the elements P ₁ and P ₂ or the elements P ₅ and P ₆ are selected to accumulate tracking lines.

In other words, in the present embodiment, when the boundary line of the elements P ₁ and P ₂ selected by this selection coincides with the center line of the tracking line 4, the boundary line between the elements P ₃ and P ₄ is formed. It is on the center line of the data tracks (D _a), on the other hand, when the center line of the element (P ₅₎ element (P ₆₎ border and track line (4a) of it coincides, the element (P ₃₎ and (P ₄₎ The boundary line between the and lines is disposed above the center line of the data track D ₆ . 12 shows the state of the former. The two sets of the light receiving elements P ₁ and P ₂ and the two sets of the light receiving elements P ₅ and P ₆ simultaneously perform functions. That is, when the spots T _a and T _b capture the tracking lines 4 in a state where the center is not displaced in the field of view, respectively, the amounts of light received by the elements adjacent to each other are large, and The distribution of brightness is approximately even between the elements. On the other hand, when the tracking line is in a part of the field of view, the light reception amount is small and the distribution of brightness is nonuniform.

In this embodiment, cracking is traced using this property. The tracking circuit is shown in FIG. The tracking circuit shown in FIG. 13 is composed of two systems for tracking A and tracking B, and is selected by the tracking A selection signal or the tracking B selection signal. That is, the tracking circuit, the light-receiving element (P ₁₎ and (P ₂₎ and (P ₅₎ and the amplifier (12 _a) to be (P ₆₎ is connected, an amplification for each photoelectric output comprising a tracking sensor ( 12 _b ), (12 _c ) and (12 _d ), and a differential circuit (13 _b ) which extracts the difference signal B from the outputs of their amplifiers (12 _c ) and (12 _d ), and the amplifiers (12 _a ), (12 _b) be connected to the amplifier 15 and the differential circuit (13 _b) for amplifying the output of taking out a difference signal a at the output differential circuit (13 _a) and the differential circuit (13 _b), and (13 _a) of the tracking B An analog switch 14b for connecting the output of the differential circuit 13b to the heavy amplifier 15 by a selection signal and a differential circuit 13a for connecting the differential circuit 13a by selection of the tracking A selection circuit. And an analog switch 14a for connecting the output of the amplifier to the amplifier 15.

Next, the operation of the present embodiment will be described with reference to the respective drawings as an example of reading data.

In the case of writing, the tracking action is the same as that of the reading. Now, in the recording area (2), it is assumed that data written in the arbitrary data recording area 3 is read. At the time of reading, similarly to the second embodiment, an optical beam is formed by the optical system shown in FIG. When the reflected light from the optical recording medium 1 is reflected by the beam splitter 9 and emitted to the outside of the optical system, the emitted light is incident on the light receiving element group P. At this time, the three light beams form a writing / reading spot WR, a tracking detection spot T _a , and a T _b , and as shown in FIG. 12, above the light receiving element group P. Form an image of the area. Each of the light receiving elements P ₁ and P ₂ and P ₅ and P ₆ receives the beam and outputs a photocurrent approximately proportional to the amount of incident light. These photocurrent outputs are voltage amplified as amplifiers 12a, 12b, 12c, and 12d, respectively, and the second second circuit 13a of the former is connected to the differential circuit 13b. The difference signals A and B are detected, respectively. Here, if the light quantity distribution of the light beam image of the tracking beam spot T _a irradiated across the _two light receiving elements P ₁ and P ₂ is equal to both sides, both light receiving elements P ₁ and ( The photoelectric output of P ₂ ) becomes the same.

For this reason, this difference signal A becomes zero. This is a case where the tracking line 4 is inserted in the tracking detection spot T _a by matching the center position thereof. When the center of the tracking detection spot T _a and the center of the tracking line 4 do not coincide with each other, the photoelectric outputs of the light receiving elements P ₁ and P ₂ O are not the same. Signal A is output. Similarly, the image of the tracking detection spot T _b is projected to the light receiving irradiation P ₅ and P ₆ , and the differential circuit 13a is adapted to the displacement of the tracking line 4 entering the spot T _b . The difference signal B corresponding to the displacement is output. These difference signals A and B are selected by the analog switches 14a and 14b and amplified as the amplifier 15. The amplified signal is output as a tracking error signal and used as a signal of a tracking error warning or as a tracking error correction signal. For example, when the center of the tracking detection spot T _a and the center of the tracking line 4 do not coincide with each other, the difference between the output signals of the light receiving elements P ₁ and P ₂ becomes large. Since the signal A becomes large, the tracking error is corrected by moving the objective lens 11 to reduce this difference signal A by a control mechanism (not shown). By the way, which of the two data tracks (D _a ) and (D _b ) in the same data recording area 3 is read out depends on a command from a control device (not shown). This command is output as a tracking A selection signal and a tracking B selection signal. Assuming that the tracking A selection signal is output now, in the tracking state shown in FIG. 10 described above, the difference signal A is output in the state of 0, and the data of the data track D _a is read out. The reading is performed as the light receiving elements P ₃ and P ₄ . By the way, if only reading is performed, there is one light receiving element. However, in this embodiment, since the focusing control is performed, two elements are used in a set.

The light receiving elements P ₃ and P ₄ may be read by focusing only by a separate read only orphan element. On the other hand, when the tracking B selection signal is outputted, the difference signal in the differential circuit 13b is outputted via the amplifier 15. Here, when the optical system is in the tracking state shown in Fig. 11, the difference signal B is in a state of approximately zero. When the tracking line put on the tracking detection spot T _b in the light receiving elements P ₅ and P ₆ is displaced, the cardan difference signal B is output from the differential circuit 13b.

Therefore, the control mechanism (not shown) moves the objective lens 11 of the optical system in accordance with the difference signal B to correct the tracking error.

However, when the amount of correction is large, correction is made by moving the optical system and the optical recording medium relatively.

Example 6

The tracking method of the sixth embodiment of the present invention shown in FIG. 14 is an example of performing double density recording in the same manner as in the fifth embodiment, and is applied to the writing / reading of the same optical recording medium as the fifth embodiment. do. In the tracking method of the sixth embodiment, the write / read spot WR is placed in the center of the tracking detection spots T _a and T _b , and the interval f is closest to each data track. It is set to be equal to the interval g from the tracking line. In other words, f = g. Of course, arrangement | positioning of each hand element in the light-receiving irradiation group which detects these optical areas is also performed according to this. In addition, the other structure and operation | movement of this embodiment are the same as that of the said 5th embodiment.

Example 7

The seventh embodiment of the present invention shown in Figs. 15 and 16, respectively, is a modification of the fifth and sixth embodiments and includes a write / read spot WR, a tracking detection spot T _a , and a T _b . The intervals between and are equally extended. The example shown in FIG. 15 has a relationship of f = 2d-g, while the example shown in FIG. 16 has a relationship of f = d + g. Of course, arrangement | positioning of each light receiving element in the light receiving element group which detects these optical areas is also performed according to each. In addition, the other structure and operation | movement of this embodiment are the same as that of the said 5th embodiment. By the way, the relationship between (f), (d), and (g) in the fifth to seventh embodiments can be generalized and expressed as f = nd ± g, including all of the above embodiments. .

Accordingly, various forms different from the above embodiments can be realized.

Example 8

17 shows an eighth embodiment of the tracking method of the optical recording medium of the present invention.

Note that in Fig. 17, ① to ⑥ both indicate the tracking detection spot S and the writing / reading spot M, but these are not separate and the same is present at different positions at different times. It is an indication for convenience.

However, it is good also as a structure which exists in multiple numbers.

This embodiment is applied to the optical recording medium 1 of the type as shown in FIG. 2 in which two data tracks are set for each data recording area 3, similarly to the first embodiment.

d/2의 배치간격으로 되도록 배치하고 있다.In this embodiment, among the plurality of light beams formed by the same optical system as described above, one tracking detection spot formed as the sub-beam S and one write / read out formed as the main beam M are described. The spots are arranged side by side in the width direction of the data recording area 3. The tracking detection spot corresponds to the tracking detection spot T in each of the above embodiments, and also corresponds to the writing / reading spot and the writing / reading spot WR in the respective embodiments. In the present embodiment, the former is denoted by the tracking detection spot S, and the latter is denoted by the writing / reading spot M. These spots (S) and (M), in the case of the present embodiment, if the interval of the tracking line 4 is d, f

It is arrange | positioned so that it may become a d2 | interval spacing.

In the plurality of light beams separated as the diffraction gratings 8 of the optical system, one light beam is a beam for writing or reading, and the other light beam is a beam for tracking line tracking. The arrangement relationship between these beams forms the above-described writing / reading spot M and tracking detection spot S. FIG. That is, in the present embodiment, these beams form a write / read spot M and a tracking detection spot S. FIG.

The light-receiving element group P is formed together with the optical system, and receives the light beam drawn out of the optical system as the beam splitter 9, and functions as a tracking line tracking and reading sensor. The light receiving element group (P) is formed of a pin photo diode of a semiconductor light-receiving element such as, for example, the four elements (P ₁ ~P ₄₎ a configuration disposed in array form as shown in Figure 18 do. In this embodiment, two pairs of elements P ₁ and P ₂ are used for reading, and elements P ₃ and P ₄ are for tracking line tracking. For this reason, in this embodiment, the light receiving element for tracking line tracking is fixed to the light receiving elements P ₃ and P ₄ .

Therefore, as shown in FIG. 19, the differential circuit 13 is connected to the outputs of the light receiving elements P ₃ and P ₄ through the amplifiers 12a and 12b as tracking tracking circuits, respectively.

When two light receiving elements are used and one side is used for tracking and the other side is used for reading, the tracking tracking circuit and the reading circuit are alternately connected to each other. As described above, in this embodiment, the tracking detection spot S and the writing / reading spot M are formed one by one, and in order to perform tracking control corresponding to two sides of the tracking line 4. The tracking detection spot S is configured to write / read data by a mode (hereinafter referred to as A mode) in which one side of the tracking line 4 tracks the edge 4a.

For example, in the A mode, the tracking detection spot S and the write / read spot M are written in the respective data recording areas in the order shown in Figs. / Read. On the other hand, in the B mode, the tracking detection spot S and the write / read spot M in the order shown in ④, ⑤, and ⑧ in FIG. 17 write / read data in each data recording area. Make a bet.

As described above, the writing / reading spot M and the tracking detection spot S are aligned with the objective lens 11 so as to match the position of the data track to which the writing / reading spot M is to be written. It moves so that these reflected light may move on the element group P in the parallel direction.

That is, in the present embodiment, by such a movement, the boundary lines of the irradiation P ₃ and P ₄ are the edges of the tracking line 4 formed as reflection images on the elements P ₃ and P ₄ . When (4a) or (4b) coincide, the absolute value of the output of the differential circuit 13 becomes the maximum, respectively. 17 shows the relationship between these edges and the output waveform of the differential circuit 13.

만큼 편이된 위치에 배치된다. 한편, 추적검출 스포트(S)가 트래킹 라인의 한쪽의 에지(4a)를 추적하고 있을때에, 써넣기/읽어내기 스포트(M)가, 데이터 기록영역(3)의 폭방향의 중심(0)에서 해당 트래킹 라인(4)에 가깝게 되는 방향으로 대략

만큼 편이된 위치에 배치된다.In this embodiment, on the nearest value from the maximum value (the waveform ⓑ points shown in claim 17 degrees) when, the element (P ₁₎ and (P ₂₎ border and, with the element (P ₁₎ and (P ₂₎ It arrange | positions so that the center line of the target data track D _a or D _b formed by the reflection image may substantially correspond. In other words, when the center of the tracking detection spot S is located inward from each of the edges 4a and 4b of the tracking line 4 by Δ, the tracking tracking spot S is brought into a normal tracking state. As a result, if the width of the tracking line 4 is W, when the tracking detection spot S is tracking one edge 4a of the tracking line, the write / read spot M is set to the data recording area ( 3) in the direction from the center (0) in the width direction of the width direction closer to the tracking line (4)

It is arranged in a position shifted by. On the other hand, when the tracking detection spot S tracks one edge 4a of the tracking line, the write / read spot M corresponds to the center 0 in the width direction of the data recording area 3. In a direction close to the tracking line 4

It is arranged in a position shifted by.

Next, the tracking operation of data writing according to the present embodiment will be described with reference to the respective drawings. Also in the case of reading, the tracking action is the same as in the case of writing. Now, in the recording area 2, it is assumed that data is written into an arbitrary data recording area 3. In the same manner as in the second embodiment, the reflected light beam from the optical recording medium 1 irradiated by the light beam from the light source 6 of the optical system is reflected by the beam splitter 9 and is emitted to the outside of the optical system. do. The emitted light by reflection at the tracking detection spot S and the write / read spot M is incident on the light receiving element group P, and as shown in FIG. 18, on the light receiving element group P. As shown in FIG. An image of these spots is formed. Each of the light receiving elements P ₂ and P ₁ and P ₄ and P ₃ receives the beam and outputs a photo current approximately proportional to the amount of incident light. The photocurrent outputs of the light receiving elements P ₃ and P ₄ are voltage amplified as the amplifiers 12a and 12b and input to the differential circuit 13, respectively, so that a difference signal is detected. Here, in the case where the edge of the tracking line is included in the light non-critical light quantity distribution of the tracking detection spot S irradiated over the light receiving elements P ₃ and P ₄ , which are two sets, the light quantity distribution is at this edge portion. Since it changes rapidly, the photoelectric outputs of both light receiving elements P ₃ and P ₄ do not become the same. As a result, this difference signal does not become zero. On the other hand, when the edge of the tracking line is not included in the light non-critical light quantity distribution of the tracking detection spot S irradiated over the light receiving elements P ₃ and P ₄ , the light quantity distribution is equal, so that both light receiving elements The photoelectric outputs of (P ₃ ) and (P ₄ ) become the same. As a result, this difference signal becomes zero. The difference signal is compared in the comparison circuit 17 with one of the reference voltages of the reference power source 18a or 18b.

The reference voltage 18a or 18b sets the reference voltage so that the former corresponds to the edge 4a of the tracking line and the latter corresponds to the edge 4b of the tracking line. Now, assuming that the tracking detection spot S and the write / read spot M are moved in the width direction of the data recording area 3, the differential circuit 13 shows the difference in waveforms as shown in FIG. The signal is output. In FIG. 17, the zero point indicates a state in which the edge of the tracking line does not appear in the tracking detection spot S, that is, the entire width direction of the tracking line is stored in the spot S, or the tracking line spot. It represents one of the states not completely enclosed in (S).

In addition, the minimum value is a state where the center line of the tracking detection spot S and the edge 4a of the tracking line coincide, and the maximum value is the edge line 4b of the tracking line with the center line of the tracking detection spot S. Indicates a matching state.

In the present embodiment, however, the tracking target value is a value slightly deviated from the minimum value or the maximum value as described above.

That is, in Fig. 17, the point indicated by ⓐ and ⓑ is the target value as the intersection point of the waveform and the dotted line.

Therefore, the reference voltage of the reference power source 18a or 18b may be set to be their target value.

In the comparison circuit 17, the difference signal and the reference voltage are compared, and when both sides coincide, a normal signal is output, while when both sides coincide, an error correction signal is output.

Here, in coincidence, not only a perfect match between the difference signal and the reference voltage, but also a certain allowable range may be provided.

The error correction signal may be a warning signal only for indicating a mismatch between the difference signal and the reference voltage. However, in the present embodiment, the control performs tracking control in accordance with the degree of mismatch between the difference signal and the reference voltage. The mechanism (not shown) can be used as a feedback signal.

For example, when the center of the tracking detection spot S and the center of the tracking line 4 do not coincide with each other, the difference between the output signals of the light receiving elements P ₃ and P ₄ becomes large and the difference signal Is turned on, and the tracking mechanism is corrected by moving the objective lens 11 so that the difference signal is made smaller by a control mechanism (not shown).

However, when the amount of correction is large, the correction is made by moving the optical system and the optical recording medium relatively.

By the way, if writing is now performed by the mode A, if the tracking is normal, the write / read spot M is positioned on the target data track D _a .

Here, the specific position of the data track is checked.

Thereby, this beam irradiation part changes locally, such as melting and blackening, and forms the shape of the image of the writing / reading spot M where optical states, such as reflectance, differ from another part.

This optical state becomes point 5, and data is recorded as a digital value.

The order of writing data to the optical recording medium can be in various forms, but in the case of the present embodiment, first, the sequential data is written into each data recording area 3 in the A mode, and then the B mode is used. Sequential data is written into each data recording area 3 in FIG.

That is, when writing to a certain data track is finished, the optical system and the optical recording medium are moved relatively in the width direction of the data recording area, so that the tracking detection spot S is moved to the edge 4a of the next tracking line 4. Set to the position of.

After the writing of the data from the A mode to the entire data recording area 3 is finished, the data is written to the entire data recording area from the B mode.

In Fig. 17, ① to ③ are A mode, and ④ to ⑥ are B mode.

In addition, the light receiving elements P ₁ and P ₂ can be used as a monitor in a writing state during writing.

Here, in the above-mentioned light receiving element group, two elements are used as a set for the light receiving elements P ₁ and P ₂ . In this embodiment, the focusing control is also performed.

Further, the light receiving elements P ₁ and P ₂ may be dedicated to focusing, and the reading may be performed by a separate read only light receiving element.

In this way, the data of all data tracks can be written by writing sequential data according to the tracking.

In this case, random access can also be performed by difficulty such as counting the number of tracking lines.

In the present embodiment, when reading out data, light beams having reduced outputs are irradiated so as not to locally melt the beam irradiating portion.

Modification of Example

The present invention relates to an optical recording medium and a tracking method thereof, and can be of various forms.

Accordingly, each of the above embodiments is not limited to some of them, and more various modifications are possible.

Next, some of these modifications are shown.

(1) In the above embodiment, an example in which a plurality of light beams are formed by one light source is shown. However, the light beams may be formed by a plurality of light sources, respectively.

(2) In the above embodiment, an example in which two or three data tracks are arranged in a data writing area is shown, but more data tracks can be arranged.

However, the arrangement relationship of the data tracks is not necessarily limited to the same interval.

In each of the above embodiments, an example in which a plurality of data tracks are set in the data recording area is shown, but only one may be configured. In this case, in the present invention, one formed is the width of the data recording area. Being at a position shifted from the center of the direction, at a position shifted in the opposite direction, further recording is possible.

(4) The above embodiment performs tracking on the basis of a tracking line continuously formed in a band shape, but can also be applied to a tracking line formed by forming a dotted line.

(5) In the ninth embodiment, the tracking is performed based on the slightly inside of the edge of the tracking line, but the edge may be used as the reference.

(6) In each of the above embodiments, the distance between the tracking detection spot and the writing / reading spot is defined as the interval between the optical beams formed by the optical system, and also the tracking line width, data recording area width, and data track width of the optical recording medium. The number can be set in various ways.

Claims (20)

Data recording area 3 on the optical recording medium 1, along the tracking line 4, data tracks D _a and D _b are set to write or read data. In the band-shaped data recording area 3 interposed between the tracking lines 4, at least two data tracks formed at positions symmetrically shifted from the center of the width direction of the data recording area 3 ( An optical recording medium comprising D _a ) and (D _b ). The optical area according to claim 1, wherein the optical area is formed to move the optical recording medium 1 relative to the medium 1 to track the tracking line 4, and in association with the optical area for tracking line tracking. An optical area for moving, writing or reading, and formed on the optical recording medium 1, wherein the positional relationship of the area is written / read when the tracking optical area tracks the tracking line 4 And a data track (D _a ) and (D _b ) so that the betting optical area moves upward at a position shifted from the center of the width direction of the data recording area (3). The optical recording medium according to claim 2, wherein the reflected light of the tracking optical region is incident on an element for tracking detection through an optical system and configured to track the tracking line (4) by detecting a tracking control signal. 4. The writing of data according to claim 3, wherein a pattern of optical change is formed at a data track setting position of the data recording area 3 by optical energy supplied to the writing optical area using an optical system common to tracking. An optical recording medium configured to carry out. 4. The apparatus according to claim 3, wherein the optical signal in common with the tracking is used to detect a signal written by detecting the reflection intensity of the optical change pattern formed at the data track setting position from the reflected light of the optical area for reading. Optical recording medium. The data track (D _a ) according to claim 2, wherein a plurality of write / read optical areas are set in the data recording area (3) when the tracking optical area tracks the tracking line (4). And (D _b ) configured to be movable over the corresponding data track. Tracing the optical areas arranged in parallel to at least two places at predetermined intervals in the width of the data recording area 3; and the writing / reading optical area and each tracking optical area in the tracking process. In consideration of the optical area for writing / reading and the positional relationship, the process of tracking the tracking line 4 by the tracking optical area in either place and the data area for writing / reading ) corresponding to any one of the data tracks (D _a), (D _b) to be located above and to the process for tracking the other tracking optical zone is the tracking area (4), the optical zone for the bet is sseoneotgi / read in And a step of positioning the data track (D _a ) or (D _b ) on the other of the data recording areas (3). 8. The optical recording medium according to claim 7, further comprising projecting a light beam onto the optical recording medium 1 formed as an optical spot through the optical system, respectively, for the tracking optical area and the writing / reading optical area. Tracking method. 8. The data tracks (D _a ) and (D _b ) of claim 7 based on the edges (4a) and (4b) along the data (D _a ), (D _b ) of the tracking line (4). The tracking method of the optical recording medium, characterized in that it further comprises the step of tracking. The method of claim 9 wherein the said tracking line 4, data track (D _a), (D _b) to follow the edge (4a), to the data tracks on the basis of slightly inside of (4b) (D _a), ( D _b) a tracking system for an optical recording medium characterized in that the track further comprises a process for. The edge of the tracking line 4 according to claim 9 or 10, wherein the two light receivers P ₁ , P ₂ , P ₃ , P ₄ , and P ₅ , P ₆ are one set. The upper part of 4a) and 4b is hidden, and the difference or ratio of the output of these light receiving elements P ₁ , P ₂ , P ₃ , P ₄ , and P ₅ , P ₆ is previously known. A tracking method of an optical recording medium further comprising the step of tracking to correspond to the set reference value. 12. The method of claim 11, of the tracking line 4, data track (D _a), (D _b) to follow the edge (4a), to the data tracks on the basis of slightly inside of (4b) (D _a), ( A method of tracking an optical recording medium, comprising the step of tracking D _b ). The light reflected elements P ₁ , P ₂ , P ₃ , P ₄ , and P ₅ , P ₆ according to claim 12, wherein the reflected light of the tracking optical region is a pair of two units for tracking detection through an optical system. The edges 4a and 4b of the tracking line 4 are formed by the incident process and the light receiving elements P ₁ , P ₂ , P ₃ , P ₄ , and P ₅ , P ₆ . The difference or ratio of the process of detecting the slightly inside of the light source and the outputs of the light receiving elements P ₁ , P ₂ , P ₃ , P ₄ , and P ₅ , P ₆ so as to correspond to a preset reference value. Tracking method of an optical recording medium which consists of a process of tracking. 15. The patterning device according to claim 13, wherein a patterned pattern of mechanical change is formed at the data track setting position of the data recording area 3 by the optical energy supplied to the writing optical area using an optical system common to tracking. The tracking method of an optical recording medium which includes the process of writing. 13. A signal according to claim 12, wherein the reflection intensity of the patternion by the patternion of the optical change formed at the data track setting position from the reflected light of the reading optical area is detected and written using an optical system common to tracking. The tracking method of the optical recording medium including the process of reading the. 16. The optical recording medium (1) according to any one of claims 10 or 12 to 15, wherein the tracking optical area and the writing / reading optical area are respectively optical beams on the optical recording medium (1) as optical spots through an optical system. Tracking method of the optical recording medium further comprises a projection process. 11. The process according to claim 9 or 10, wherein the tracking optical area and the writing / reading optical area are projected onto the optical recording medium 1 as an optical spot through an optical system, respectively, and for the tracking. The light reflected in the optical spot of the optical region is received by the light receiving elements P ₁ , P ₂ , P ₃ , P ₄ , and P ₅ , P ₆ , which are two sets, and the edge of the tracking line 4 is received. While detecting slightly inside of (4a) and (4b), the difference or ratio of the outputs of these light receiving elements P ₁ , P ₂ , P ₃ , P ₄ , and P ₅ , P ₆ , A tracking method of an optical recording medium comprising a process of tracking to correspond to a preset reference value. The method of claim 7, further comprising the step of tracking the data tracks (D _a ), (D _b ) of the tracking line (14) with respect to the center line (0) along the longitudinal direction. Tracking method of recording medium. 8. The optical recording medium according to claim 7, comprising the step of changing the distance between the optical area for writing / reading and the optical area for tracking, changing the positional relationship between the two sides, and tracking the other data track. Tracking method. The optical area for writing / reading and the optical area for tracking are changed in order on the optical recording medium 1 to change the positional relationship between the two sides, and to perform tracking on another data track. The tracking method of the optical recording medium to further include the process.

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