JPH05298698A - Method for recording optical information - Google Patents

Abstract

PURPOSE:To effectively improve recording density by revising the recording interval or the recording length of a pit according to recording density selecting data and recording the data by the fixed number of bytes per sector. CONSTITUTION:By a controller 30, a sector format selection signal 36 and a recording density selection signal 38 are outputted to a sector position detection circuit 27 and a sector format and recording density are selected. Then an optical head 21 is sought to a required track and the write beam of a high power is modulated according to the data to be recorded and outputted from a laser diode 21a through a modulation/laser drive circuit 31 and the data is recorded on the required sector. In such a manner, since the recording interval or the recording length of the pit are revised according to the recording density selecting the data and the fixed number of bytes per sector is recorded, the recording density is improved effectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording method for optically recording information on an optical recording medium such as an optical card or an optical disk.

[0002]

2. Description of the Related Art Generally, an optical recording medium has an extremely high recording density as compared with a magnetic recording medium, and therefore, its application has been started for recording a large amount of information. Among them, an optical card has a storage capacity several thousand times to 10,000 times larger than a magnetic card and cannot be rewritten like a WORM type optical disk, but its storage capacity is as large as 1 to 2 MB. , Application to applications such as personal health management cards that store historical data, prepaid cards,
Application to customer management is also considered, and some have started experiments. Further, the use of WORM type optical discs has begun to be expanded for document files and the like, and magneto-optical discs that are built into personal computers have begun to appear on the market.

On the other hand, there has been conventionally proposed a method of recording information on the optical recording medium as described above at a higher density. Figure 7
FIG. 8 and FIG. 8 are views for explaining the high-density information recording method and the reproducing method thereof, which are disclosed in JP-A No. 2-172020. In FIGS. 7 and 8, 4
0 is a guide track, 41a to 41d are recording pits, 4
2a indicates a first laser beam spot, 42b indicates a second laser beam spot, and 43 indicates a center line of the track. At the time of recording, as shown in FIG. 7, tracking is performed so that the two laser beam spots 42a and 42b are symmetrical with respect to the track center line 43, and pits are recorded in a staggered manner on the track. As shown in FIG. 8, the laser beam spot 42b is turned off, and tracking is performed so that the laser beam spot 42a is located at the center of the track, and the recording pits recorded in a staggered pattern are reproduced. Here, the interval W of the recording pits that are recorded in a staggered manner is an interval that allows reproduction with one laser beam spot, that is, 1 / the track pitch.
It is set to 2 or less.

As another method for increasing the recording density of an optical recording medium, it is known that the track pitch is reduced to increase the number of tracks and the light beam spot is reduced.

[0005]

However, in the recording / reproducing method disclosed in Japanese Unexamined Patent Application Publication No. Hei 2-172020, two lasers are required at the time of recording, resulting in an increase in cost. In addition, there is a problem that the servo circuit becomes complicated because the laser spots must be accurately tracked so that they are positioned in a staggered manner on the track. In addition, since the pits are read by one laser spot during reproduction, a tracking servo circuit different from that used during recording is required, which causes a problem that the device is complicated and the cost is high.

Further, in the method of decreasing the track pitch to increase the number of tracks and decreasing the light beam spot to increase the recording density, it is necessary to increase the tracking accuracy as compared with the conventional track pitch. Therefore, there is a problem that the tracking servo circuit becomes complicated, and compatibility with a medium having a conventional track pitch cannot be maintained, which causes inconvenience to a user who uses the recording medium.

The present invention solves the above-mentioned conventional problems, can effectively improve the recording density with a simple circuit structure, and can maintain compatibility with conventional optical recording media. The purpose is to provide.

[0008]

In order to achieve the above object, according to the present invention, one recording density is selected from a plurality of preset recording densities, and an optical density is selected according to the selected recording density. The recording interval of pits or the recording length of pits in the direction in which the beam scans the track of the optical recording medium is changed to record data on the optical recording medium with a constant number of bytes per sector.

[0009]

In such a recording method, when the recording density is low, the data has a pit interval or pits n times (n is a real number) the pit interval or the pit length formed on the optical recording medium when the recording density is the highest. It is long and is recorded with a fixed number of bytes per sector.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of an optical recording medium used in the optical information recording method of the present invention. This example shows a write-once type optical card 1, in which an optical recording section 3 having a plurality of tracks 2 which are parallel to each other and an ID section 4 in which track information is recorded at both ends thereof corresponding to each track.
A and 4B, and a data section 5 is provided between the ID sections 4A and 4B. Here, the ID sections 4A and 4B are pre-recorded in advance when the optical card 1 is manufactured.

2A and 2B are enlarged views of the track 2 shown in FIG. 1. FIG. 2A shows the case of one track and one sector.
FIG. 2B shows the case of one track and three sectors. 2A and 2B, reference numerals 201a to 201
d is the sector data recorded on track 2
a and 202c perform a gap between the ID portion 4A and sector data, 202b and 202d perform a gap between the ID portion 4B and sector data, 203a and 203b perform a gap between sector data, and 204 performs tracking. For each of the gaps 202a-
202d and 203a, 203b are provided to absorb speed fluctuations when the optical card 1 is driven at a constant speed.

2A and 2B, in the conventional recording method, assuming that one sector is 1024 bytes in FIG. 2A, data is recorded as one sector 256 bytes in the case of FIG. 2B. Therefore, the recording density becomes low. In the embodiment of the present invention, data is recorded in the data section 5 at one recording density of a plurality of predetermined recording densities and one sector format of a plurality of predetermined sector formats. .. Below, 1 sector, 2 sectors, and 3 sectors can be recorded in one track in sectors of 1024 bytes.
A case will be described in which the same recording density is selected and data is recorded.

3A to 3C show a recording format in a track on the optical card according to this embodiment.
A has 1 sector per track, and FIG. 3B has 2 sectors per track.
Sectors, and FIG. 3C shows a case where three sectors are recorded on one track. 3A to 3C, reference numeral 1
0 indicates a guide track, 11a and 11b indicate an ID part in which a track number is recorded, and 12a to 12f indicate recorded sectors. Each sector includes an error correction code and has a capacity of 1024 bytes as user data. have. Further, a portion (gap) in which nothing is recorded is provided between each of the ID parts 11a and 11b and the sector and between the sectors. The dimensions shown in FIGS. 3A to 3C indicate the positions where sectors are actually recorded on the optical card.

4A to 4C show a part of the pits recorded in each sector shown in FIG. 3, and FIG. 4A shows sector 1
2a, FIG. 4B corresponds to sector 12b, and FIG.
Corresponds to sector 12d. In this embodiment, the data modulation rule is MFM and pit position recording (recording between marks) is shown. 4A to 4C, reference numeral 1
3a to 13d indicate pits recorded on the track. Here, the MFM is provided between the pits 13a and 13b.
The minimum recording interval is 1τ, the distance between pits 13b and 13c is 1.5τ, and the distance between pits 13c and 13d is 2τ.

In FIG. 4A, if 1τ corresponds to 6 μm, 1.5τ becomes 9 μm and 2τ becomes 12 μm,
In the case of FIG. 4B, the recording density is twice that of the case of FIG. 4A, so 1τ is 3 μm and 1.5τ is 4.5 μm, 2
τ is 6 μm, and in the case of FIG. 4C, the recording density is
Since it is three times as large as in the case of A, 1τ is 2 μm, 1.5τ is 3 μm, and 2τ is 4 μm. In this example, FIG.
In this case, the maximum recording density is the case, and the minimum pit interval in that case is 2 μm. Therefore, considering the resolution of the optical system, the recorded pit size needs to be about 1 μm in the track direction. In addition, regarding the length of the recording pit in the tracking direction (the direction crossing the track), the length in FIG.
The same applies in each case of C, and about 2.5 μm is selected. Therefore, the pit recorded on the track has a shape of approximately 2.5 μm width × 1 μm length. With such a pit shape, the numerical aperture (N / A) of the objective lens of the optical pickup is increased, and the output of the semiconductor laser as the light source is narrowed down to spread the light beam in the direction perpendicular to the track direction. It can be realized.

FIG. 5 is a block diagram showing the configuration of an example of an optical card recording / reproducing apparatus embodying the present invention. In this optical card recording / reproducing apparatus, the optical card 20 is moved in the track direction, and the optical head 21 is moved in a direction orthogonal to the track direction by an optical head drive motor (not shown) to record / reproduce data. Optical card 20
Is mounted at a predetermined position in a shuttle 23 integrated with a movable coil of a voice coil motor (hereinafter referred to as VCM) 25, and is reciprocally driven in the track direction by driving the VCM 25 by a VCM drive circuit 24. Shuttle 2
3, an encoder 22 for detecting the position of the optical card 20 with respect to the optical head 21 is attached to the VCM 3.
25 or the detection output of the linear scale 26 fixed to the apparatus bottom plate is supplied to the sector position detection circuit 27. In addition,
The linear scale 26 has a length of 50 on the optical card.
Select a pulse output that can be obtained at a μm pitch.

The optical head 21 includes a laser diode 21.
The writing or reading light from a is passed through the diaphragm 21d so as to have a width of 2.5 μm × 1 μm on the optical card, and then is irradiated onto the optical card 20 via the optical system 21b.
The reflected light is made incident on the detector 21c. The output of the detector 21c is supplied to the demodulation circuit 28 to obtain the read signal 35, and is also supplied to the focus / track servo circuit 29 to detect the focus error signal and the track error signal, whereby the beam on the optical card 20 is detected. The driving of the optical head 21 in the focusing and tracking directions is controlled so that the spot always follows the track in a focused state. Further, the read signal 35 is supplied to the controller 30 so that the data reproduction signal and the track address information are detected here.

Next, the operation of the controller 30 will be described. Since this optical card recording / reproducing apparatus selects three recording densities, it is necessary for the controller 30 to recognize which recording density is the first in recording / reproducing operation. The method is as follows: (1) A command is given from a host computer (not shown) for recognition.
(2) In a specific area of the optical card (a specific sector of a specific track, for example, the first sector of the first or last track),
Data indicating the recording density used in the optical card is recorded, and the area is read and recognized when the optical card is inserted into the device. (3) A command from the host computer during data recording It is conceivable to recognize the data by the frequency of the preamble area (the synchronization pull-in area of the reproducing PLL circuit) of the recorded data during data reproduction. The controller 30 recognizes the recording density by any one of the above methods (1), (2) and (3) or a combination thereof, and as the recording density selection signal 38, the sector position detection circuit 27, the demodulation circuit 28, and the modulation. -Supply to the laser drive circuit 31 to perform recording / reproducing operation.

The data recording operation will be described below.
First, the controller 30 outputs a format selection signal 36 indicating the type of sector format and a recording density selection signal 38 to the sector position detection circuit 27 to select the sector format and the recording density. Next, after the optical head 21 is sought to a desired track for recording data, a low-output read light is emitted from the laser diode 21a via the modulation / laser drive circuit 31, and
The VCM drive circuit 24 is controlled to drive the shuttle 23 in the track direction, and the ID section 11a or 11b (see FIG. 3) at the end of the optical card 20 is read to confirm that it is the target track. Here, since the ID sections 11a and 11b are pre-recorded at the lowest recording density, the PLL circuit inside the demodulation circuit 28 has the ID section 11a or 11b.
Prior to reading, the free run is performed in the vicinity of the frequency, and the accurate frequency and phase are pulled in the preamble area at the head of the ID section to be read.

Next, the controller 30 outputs the recording density selection signal 38 and the sector position detection signal 3 from the sector position detection circuit 27 according to the sector format and the recording density.
7, the high power writing light is modulated from the laser diode 21a through the modulation / laser driving circuit 31 according to the data to be recorded, and the modulated light is output, thereby recording the data in the desired sector. At this time, the controller 30 rearranges the data to be recorded and switches the modulation rule according to the carrying direction of the optical card 20, and outputs the data to be recorded to the modulation / laser drive circuit 31.

When reproducing data, first,
Similarly to the above, the controller 30 outputs the format selection signal 36 and the recording density selection signal 38 indicating the type of the sector format to the sector position detection circuit 27 to select the sector format and the recording density. Note that the recording density selection signal 38 is output from the controller 30 immediately after the read operation is started in the case of the recognition method of (3) described above. Next, after the optical head 21 is sought to a desired track for reproducing data, modulation /
The laser diode 21a emits low-output read light via the laser drive circuit 31, and the VCM drive circuit 24 is controlled to drive the shuttle 23 in the track direction. ID part 1
Read 1a or 11b to confirm that it is the target track. Next, the controller 30 outputs the recording density selection signal 38 and the sector position detection signal 3 from the sector position detection circuit 27 according to the sector format and the recording density.
The sector data at the desired sector position is reproduced on the basis of 7. At this time, the demodulation circuit 28 rearranges the data and switches the modulation rule according to the carrying direction of the optical card 20.

In such an optical card recording / reproducing apparatus, the sector position detection circuit 27 corresponds to a sector division according to the sector format and recording density selected by the format selection signal 36 and the recording density selection signal 38 from the controller 30. When the optical head 21 approaches the position on the optical card, the sector position detection signal 27 is output. FIG. 6 shows such a sector position detection circuit 2
7 is a circuit diagram showing an example of the structure of an optical card according to a format selection signal 36 for selecting the number of bytes in one sector and a recording density selection signal 38 for selecting the number of minimum pit intervals. A format selector 32 that outputs a predetermined value corresponding to a sector delimiter position, and a counter 34 that counts output signals from the encoder 22.
And a comparator 33 that compares the predetermined value output from the format selector 32 with the output count value from the counter 34, and outputs a sector position detection signal 37 indicating the start position of the sector when the two match. Have.

In FIG. 6, assuming that the output pitch of the encoder 22 is 50 μm, for example, each sector 1 shown in FIG.
The left ends of 2d, 12e, and 12f are 4.95 mm and 23.65 mm, respectively, based on the left end of the left ID unit 11a.
Since it is at the position of 42.35 mm, ID the counter 34
If reset at the left end of the section 11a, the sector position detection signal 37 will be output when the outputs of the counter 34 become 99, 473 and 847, respectively. The resetting of the counter 34 is not limited to the above-described position, but a position on the optical card that serves as a reference with respect to the optical head 21, for example, a predetermined position in the edge of the optical card 20 or the prerecorded ID portion, etc. If so, it can be set arbitrarily. The sector position detection signal 37 from the sector position detection circuit 27 is supplied to the controller 30, and the controller 30 counts this signal to recognize the desired sector.

The modulation / laser driving circuit 31 drives the laser diode 21a in accordance with the modulated signal output from the controller 30 at the time of data recording, and the fundamental frequency at the time of modulation is predetermined by the recording density selection signal 38. Select the frequency of. For example, assuming that the modulation frequency is 160 KHz in the case of FIG. 3A, the recording density is 320 KHz in the case of FIG.
In this case, since the recording density is three times, each modulation is performed at 480 KHz.

Further, the demodulation circuit 28 phase-locks the PLL circuit in the demodulation circuit by the preamble portion recorded at the end of the sector for a certain period at the time of reading the sector data, but before the synchronization is pulled in by the preamble portion. Must be free run at the desired frequency. Therefore, by the recording density selection signal 38, the free-running frequency is set to 1 in correspondence with the above modulation frequency.
Switch to 60KHz / 320KHz / 480KHz. Since the information in the ID sections 11a and 11b is recorded at the lowest recording density, the recording density is read from the controller 30 before the data section is read by free-running at 160 KHz when reading the information. It switches according to the selection signal 38.

With the above-mentioned structure, desired information can be recorded with a simple circuit structure without reducing the track pitch and using a single laser beam, and thus without increasing tracking accuracy. The density can be recorded.

It should be noted that the present invention is not limited to the above-described embodiments, but many modifications and variations are possible. For example, in the above-described embodiment, one sector is 102
4 bytes, change the recording density to 1 track and
Although three sectors are recorded, the number of bytes in one sector and the number of sectors in one track can be arbitrarily changed. Further, in the optical card recording / reproducing apparatus shown in FIG. 5, the sector position detection circuit 27 outputs a sector position detection signal 38 indicating the start position of the sector, and the controller 30 counts the signal to recognize the desired sector. However, a counter for counting the sector position detection signal 38 may be provided in the sector position detection circuit 27, and its output may be supplied to the controller 30 as a sector number.

Further, in the above-mentioned embodiment, the data is recorded by pit position recording (recording between marks), but the present invention is effectively applied to the case of pit edge recording (mark length recording). be able to. Further, the optical card is not limited to the VCM, but may be configured to be driven by a combination of a rotary motor and a pulley or a conveyor belt. Further, in the above-described embodiment, the optical card having the ID parts at both ends of the track is used, but the present invention can be effectively applied to the case where the ID part is only on one side, and the data is recorded. The modulation rule of is not limited to MFM, but 1-7 modulation, 2-7 modulation, and 8/1
The present invention can be effectively applied to other modulation rules such as 0 conversion.

[0029]

As described above, according to the present invention, data is recorded in a constant number of bytes per sector by changing the recording interval of pits or the recording length of pits according to the selected recording density. The recording density can be effectively improved. Also, the width of the light beam in the tracking direction can be the same as the conventional one, and therefore recording can be performed with a single light beam without narrowing the track pitch at all, so it is easy to perform without changing the tracking servo circuit or improving the tracking accuracy. It can be implemented with various circuit configurations and can maintain compatibility with conventional optical recording media.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an optical recording medium used in an optical information recording method of the present invention.

FIG. 2 is a diagram for explaining a conventional recording method for the track of FIG.

FIG. 3 is a diagram showing an embodiment of a recording method according to the present invention.

FIG. 4 is a diagram showing a part of a pit recorded according to the present invention.

FIG. 5 is a diagram showing a configuration of an example of an optical card recording / reproducing apparatus embodying the present invention.

6 is a diagram showing a configuration of an example of a sector position detection circuit shown in FIG.

FIG. 7 is a diagram for explaining a conventional recording method for increasing recording density.

FIG. 8 is a diagram for explaining a method for reproducing the data recorded in FIG.

[Explanation of symbols]

 10 guide track 11a, 11b ID part 12a-12f sector 13a-13d pit 20 optical card 21 optical head 21a laser diode 21b optical system 21c detector 21d diaphragm 22 encoder 23 shuttle 24 VCM drive circuit 25 voice coil motor (VCM) 26 linear scale 27 sector position detection circuit 28 demodulation circuit 29 focus / track servo circuit 30 controller 31 modulation / laser drive circuit 32 format selector 33 comparator 34 counter

Claims (2)

[Claims] 1. A recording density is selected from a plurality of preset recording densities, and pit recording is performed in a direction in which a light beam scans a track of an optical recording medium according to the selected recording density. An optical information recording method, characterized in that an interval or a pit recording length is changed to record data on the optical recording medium with a constant number of bytes per sector. 2. The optical information recording method according to claim 1, wherein different data are recorded on a common recording medium with different recording densities.