JP2002109789A - Optical recording medium and optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical recording medium which can easily detect a read-in part on the optical recording medium even when the control of tracking is not in operation, and an optical disk device. SOLUTION: This is the optical recording medium in which servo areas 205 having pits which can be optically read and data areas 206 which record or reproduce the data are alternately arranged in the direction of the circumference, and the read-in part 104 is arranged at the inner radius of the medium. In addition, read-in information is recorded in the data areas of the read-in part by the pits which can be optically read, and the location of the pits at least in one servo area among the servo areas existing in the direction of the circumference is different only in the boundary of the read-in part. The optical disk device comprises a pit detector, which detects the pits on the optical recording medium, and a read-in detector which detects the read-in part from a pit- detecting signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium for optically recording and reproducing data and an optical disk apparatus.

[0002]

2. Description of the Related Art In recent years, an optical disk device used for recording / reproducing information has been increased in capacity and speed, and its application range has been greatly expanded. Hereinafter, an example of a conventional optical recording medium used in an optical disk device will be described with reference to the drawings.

FIG. 8 shows a configuration diagram of a conventional optical recording medium.
In FIG. 8, a virtual track 802 and a segment 803 obtained by dividing the track 802 into n equal parts are formed on an optical recording medium 801. Although FIG. 8 illustrates a diagram divided into twelve for the sake of simplicity, it is actually divided into 1,000 to 2,000. In the following description, 1
It is assumed that it is equally divided into 280.

FIG. 9 shows a specific configuration of the segment 803. In the segment 803, a clock pit 901 for generating a clock at the head, a first wobble pit 902 and a second wobble pit 903 for obtaining a tracking signal, and then a segment number and a track number Are distributively arranged for each bit, and address bits 904 are arranged.

[0005] As a tracking method, a sample servo method for performing tracking control so that the amount of reflected light from the first wobble pit 902 and the second wobble pit 903 becomes equal is used.

As described above, by dispersing the segment number and the track number and arranging them in the segment 803, there is a time margin from the reproduction of one address bit 904 to the reproduction of the next address pit 904. I do. During this time, the error detector can operate,
The configuration of the system becomes easy. In addition, since all the segments 803 have the same physical structure, format flexibility can be greatly increased.

[0007] Information on the address pits 904 is collected in the circumferential direction to form segment / track number data. FIG. 10 shows the structure of the segment / track number data in detail. Sixteen sets of segment / track number data are configured for one track, and one set of segment / track
The track number data is composed of data of 80 address pits 904.

[0008] Segment numbers 1001, 100 in FIG.
2 is composed of 8-bit data, and the track numbers 1005 and 1006 are each composed of 16-bit data. Also, segment numbers 1001, 1
002 error codes 1003 and 1004 are 8
Track data 1005, 1
Each of the 006 error codes 1007 and 1008 is composed of 14-bit data.

The same data is recorded in the adjacent track for the segment number 1001 and the segment number 1002, and for the error code 1003 and the error code 1004. By arranging the pits in this way, it is possible to detect the segment number even when the tracking control is not performed (the light spot is scanning the track 802).

On the other hand, a zero code 100 is located at a track position adjacent to the track number 1005 and the error code 1007.
9 (without pits) is recorded. A zero code 1010 is also recorded at a track position adjacent to the track number 1006 and the error code 1008. As a result, leakage of signals from other tracks in the tracking control state is reduced.

Further, the first bits of the segment numbers 1001 and 1002 can be easily detected by using the error codes 1003 and 1004.

As such an optical recording medium, Japanese Patent Application No. Hei.
In the optical disk in which a track is divided into one or more areas and addresses are arranged in the divided areas, an error detection code is assigned to data common between adjacent tracks in the address data. An optical disk characterized by being added. ] Is described.

[0013]

However, in the above configuration, the segment number can be read without depending on the tracking control state, but the track number cannot be read without the tracking control state. Therefore,
In the state where the tracking control is not operating, the position in the radial direction on the optical recording medium cannot be detected, and the lead-in portion formed in a part of the optical recording medium in the radial direction cannot be detected. Therefore, a mechanism for mechanically detecting the lead-in portion is required.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide an optical recording medium and an optical disk apparatus which can easily detect a lead-in portion on an optical recording medium even when tracking control is not operating.

[0015]

In order to solve the above-mentioned problems, an optical recording medium according to the present invention comprises: a servo area having a plurality of optically readable pits; and a data area for recording or reproducing data. Are arranged alternately in the circumferential direction, and a lead-in portion is arranged on the inner peripheral portion. The data area of the lead-in portion is read by optically readable pits. In information is recorded, and only at the boundary of the lead-in portion, the arrangement of pits in at least one of the plurality of servo areas in the circumferential direction is different.

In the above configuration, preferably, the lead-in portion is divided in the radial direction to form a plurality of divided lead-in portions, and the data area of the plurality of divided lead-in portions includes:
A configuration in which at least one common lead-in information is recorded, and the arrangement of pits in at least one servo area of at least one servo area in the circumferential direction is different between two adjacent divided lead-in parts. And

Preferably, in the above configuration, the pit arrangement in at least one of the plurality of servo areas in the circumferential direction is different between the inner peripheral part and the lead-in part from the lead-in part. Configuration.

In the above configuration, preferably, in each divided lead-in area, the arrangement of at least one pit in at least one servo area is the same as the arrangement where pits are present substantially continuously in the radial direction. At the boundary between the divided lead-in portions, the arrangement of pits in at least one servo area is substantially different in the radial direction.

An optical disc apparatus according to the present invention comprises: a photodetector for detecting reflected light from an optical recording medium having the above-described configuration and outputting a photodetection signal; Means, and lead-in detecting means for detecting a lead-in portion by detecting the presence or absence of a predetermined pit from a pit detection signal of the pit detecting means.

Further, the optical disk apparatus of the present invention detects a reflected light from the optical recording medium having the above-described configuration, and outputs a light detection signal, and detects a pit on the optical recording medium from the light detection signal. Pit detection means, lead-in detection means for detecting a lead-in portion by detecting a predetermined pit from a pit detection signal of the pit detection means, an optical pickup equipped with a photodetector, and an optical pickup medium Transfer means for transferring the optical pickup to the inner or outer circumference by the transfer means, and stopping the transfer in accordance with the detection signal of the lead-in detection means.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 In Embodiment 1, an example of an optical recording medium of the present invention will be described. FIG. 1 shows the configuration of the optical recording medium according to the first embodiment. On the optical recording medium 101, a virtual track center line 102 and a segment 103 obtained by dividing the track center line 102 into n equal parts in the circumferential direction of the optical recording medium 101 are formed. In addition,
Although FIG. 1 shows a state of being equally divided into 12 for the sake of simplicity of the drawing, in practice, it is preferable that the distance be equal to 500 to 2000. A lead-in section 104 is formed near the inner periphery of the optical recording medium 101.

FIG. 2 shows a detailed configuration diagram of the segment 103. The segment 103 is divided into a servo area 205 and a data area 206. In the servo area 205,
At the beginning, a clock pit 201 for generating a reproduction clock signal is arranged. Next, a first wobble pit 202 and a second wobble pit 203 for obtaining a tracking signal are arranged. Next, address bits 204 in which a segment number, a track number, and a lead-in identifier are dispersedly arranged for each bit are arranged. In the following description, the segment number, the track number, and the lead-in identifier are collectively referred to as address information. The data area 206 is used for recording and reproducing data. In the data area of the lead-in unit 104, lead-in information and the like regarding the optical recording medium 101 are recorded as pits.

The optical recording medium 101 is configured to use a sample servo method for performing tracking so that the amount of light reflected from the first wobble pit 202 and the amount of light reflected from the second wobble pit 203 are equal. .

As described above, by dispersing the address information and arranging it in the segment 103, one bit of the address bit 204 is reproduced and then the next address pit 2 is read.
There is a time margin before the 04 is reproduced. Since the error detector can operate during this time, the configuration of the system is simplified. In addition, since all the segments 103 have the same physical structure, format flexibility can be greatly increased.

Next, the structure of the address information will be described in detail with reference to FIG. In FIG. 3, track (n) is
The n-th track (where n is an integer) represents the track, and the track (n + 1) represents the (n + 1) -th track. The optical recording medium 101 has 16 pieces of address information per track. Since there is one address pit in one segment, 80 segments 103 constitute one piece of address information.

As the contents of the address information, three bits are assigned to the lead-in identifiers 301a and 301b,
Five bits are assigned to the segment numbers 302a and 302b, and error codes 303a and 30
10 bits are allocated to 3b, and track number 304 is assigned.
16 bits are assigned to a and 304b, and 15 bits are assigned to error codes 305a and 305b of the track number.

Here, referring to FIG.
4 will be described. In FIG. 4, the optical recording medium 10
1 is shown such that the inner peripheral side is upward. The horizontal direction indicates the circumferential direction of the optical recording medium 101. The innermost peripheral portion 401, the lead-in portion 104, and the lead-in portion 10, which are regions on the inner periphery than the lead-in portion 104, are sequentially arranged from the inner periphery side
4, a data portion 402 on the outer peripheral side is arranged. The lead-in section 104 is divided in the radial direction and is composed of two divided lead-in sections. The inner lead-in section is referred to as a first lead-in section 104a, and the outer lead-in section is referred to as a second lead-in section 104b. The first
Lead-in part 104a and second lead-in part 104b
In the data area 206, at least one type of common lead-in information is recorded.

The lead-in identifier 301a shown in FIG.
As 301b, the same data is recorded in adjacent tracks over a predetermined range. For example, in each area of the first lead-in section 104a and the second lead-in section 104b, at least one pit in at least one servo area has an arrangement of pits that are substantially continuous in the radial direction. It is configured so as to be arranged.
By arranging the pits of the lead-in identifiers 301a and 301b in this manner, a tracking control state (a state in which the light spot is scanning on the track center line 102).
However, the lead-in identifiers 301a and 301b can be determined.

The same data is recorded in the adjacent track for the segment number 302a and the segment number 302b, and for the error code 303a and the error code 303b. By arranging the pits of the segments 302a and 302b in this manner, it is possible to determine the segment information 302a and 302b even when the tracking control is not performed.

On the other hand, a zero code 306a is located at a track position adjacent to the track number 304a and the error code 305a.
(Without pits) is recorded. Also, a zero code 306b is recorded at a track position adjacent to the track number 304b and the error code 305b. This is to prevent crosstalk, which is leakage of a signal from an adjacent track during the tracking control state.

The first bits of the segment numbers 302a and 302b are error codes 303a and 30b.
Detection can be easily performed by using 3b.

The three-bit data constituting the lead-in identifiers 301a and 301b are distributed into three segments 103 and arranged as address pits 204.
In the following description, the lead-in identifiers 301a and 301b
Are called lead-in pits.

The arrangement of the lead-in pit is shown in FIG. Address pits 204a, 204b, and 20
4c constitutes a 3-bit lead-in pit, and thus represents 3-bit information of the lead-in identifiers 301a and 301b.

In the innermost peripheral portion 401, the address pit 20
4a, 204b, and 204c. The first lead-in section 104a includes address pits 204a and 2
04b, and no address pit 204c. The second lead-in section 104b has an address pit 204a, and does not have 204b and 204c. The data section 402 includes address pits 204a,
The configuration is such that none of 04b and 204c exists.

Accordingly, the lead-in identifiers 301a and 301b in the innermost peripheral portion 401 are as follows. 1
The lead-in identifiers 301a and 301b of the bit have "H"("H") because the address pit 204a exists.
Represents a state in which there is a pit), and the lead-in identifiers 301a and 301b of the second bit correspond to the address pit 2
04b is present, and becomes "H". The third bit lead-in identifiers 301a and 301b become "H" because the address pit 204c is present. That is, a 3-bit lead-in identifier 301a of the innermost peripheral portion 401,
301b is "H" data for all three bits. This state is represented as [HHH].

Similarly, the first lead-in section 104a
Then, the lead-in identifiers 301a and 301b are [HH
L] (“L” indicates a state without pits), and the second
In the lead-in unit 104b, the lead-in identifier 301
a and 301b become [HLL], and in the data section 402, the lead-in identifiers 301a and 301b become [LLL].
Becomes

As described above, the lead-in identifier 301a,
301b is the innermost peripheral portion 401, the first lead-in portion 10
4a, the second lead-in unit 104b, and the data unit 402 have different patterns.

With this configuration, it is possible to detect the lead-in section 104 on the optical recording medium even when the tracking control is not operating. The reason will be described below. Similarly to the conventional optical recording medium, the segment numbers 302a and 302b can be detected using the segment number error codes 303a and 303b. When the segment number is detected, three address pits 204 preceding the first address pit 204 forming the segment numbers 302a and 302b
a, 204b, and 204c can also be detected. Thus, the above-described pattern in the lead-in identifiers 301a and 301b can be detected.

As described above, the segment number 302
Since the detection of a and 302b can be performed even when the tracking control is not operating, the detection of the three-pit address pits 204a, 204b and 204c, which are the lead-in identifiers, is also performed when the tracking control is not operating. But it is possible.

[0042] Lead-in identifiers 301a, 301a, and 3a represented by address pits 204a, 204b, and 204c.
01b is the innermost peripheral portion 401, the first lead-in portion 104
a, the second lead-in unit 104b, and the data unit 402
Are distinguishable because each has a unique data pattern. This makes it possible to determine a desired portion on the optical recording medium, and as a result, the lead-in section 1
04 can be detected.

As described above, the optical recording medium according to the first embodiment has a configuration in which the pits of at least one of the plurality of servo areas in the circumferential direction are different only at the boundary of the lead-in portion. Having.

In the split lead-in portion of the optical recording medium according to the first embodiment, the arrangement of at least one pit in at least one servo area is substantially continuous in the radial direction. At the boundary, the arrangement of pits in at least one servo area is configured to differ substantially in the radial direction.

As a result, as described above, the address pits 204 in the servo area 205 constituting the lead-in identifier 301 are different between the lead-in section 104 and other areas. This constitutes an optical recording medium that can easily detect the lead-in section 104 using the lead-in identifiers 301a and 301b.

Further, since the predetermined pits are continuously arranged in the radial direction of the optical recording medium, the pits indicating the lead-in identifier in the servo area can be easily detected even when the tracking control is not operated. An optical recording medium having an extremely easy access operation to the lead-in section can be configured.

Furthermore, in the first embodiment, since different lead-in identifiers are assigned to the first lead-in section 104a and the second lead-in section 104b, only the first lead-in section 104a is used. It is possible to detect, and the reading operation of the common lead-in information can be speeded up.

In the first embodiment, no error code is added to the lead-in identifier. However, an error code such as a segment number or a tracking number is added to improve the reliability of the lead-in identifier. Is also possible. These are included in the concept of the present invention since they are added to the contents of the address pits and do not require any substantial change of the above configuration.

In the first embodiment, a clock pit is provided to generate a reproduced clock signal. However, a reproduced clock signal can be generated with other mark information such as a groove edge and a wobble pit. . Even in such a case, the above configuration does not require an essential change, and thus is included in the concept of the present invention.

Further, in the first embodiment, the position of the clock pit is provided at the head of the servo area. However, the position of the clock pit may be provided between the first wobble pit and the second wobble pit, or provided before the address pit. Is also possible. Also in this case, since the above configuration does not require any substantial change, it is included in the concept of the present invention.

Further, in the first embodiment, the position of the address pit is provided behind the servo area. However, the address pit can be provided at an arbitrary position in the segment, and a plurality of addresses can be provided in one segment. It is also possible to provide pits. Also in this case, since the above configuration does not require any substantial change, it is included in the concept of the present invention.

Further, in the present embodiment, the lead-in bit is set to 3 bits. However, the present invention is not limited to 3 bits, and the same effect can be obtained with other bits.

Further, the pattern of the lead-in identifier is
A first lead-in part, a second lead-in part, an innermost peripheral part,
It is only necessary to be able to identify the data part and the like, and it is not limited to the pattern described in the first embodiment.

Embodiment 2 In Embodiment 2, an example of the optical disk device of the present invention will be described. FIG.
7 shows a configuration of an optical disk device according to Embodiment 2. In FIG. 5, reference numeral 101 denotes an optical recording medium according to the first embodiment.
Has the configuration shown in FIG. Reference numeral 510 denotes an optical pickup on which an objective lens 501 and a photodetector 502 are mounted. The photodetector 502 detects reflected light from the optical recording medium 101 and outputs a reproduction signal s.

The reproduced signal s is input to the pit detector 505. The pit detector 505 is an address pit detector 5
03 and a lead-in bit detector 504. The address pit detector 503 outputs address pit reproduction information based on the input reproduction signal s. That is,
A detection signal AB indicating the presence or absence of an address pit on the optical recording medium 101 and a signal LP for latching the detection signal AB.
The lead-in bit detector 504 generates and outputs a 3-bit lead-in identifier LB. The lead-in identifier LB output from the lead-in bit detector 504 is
It is input to the lead-in detector 506. The lead-in detector 506 specifies the position of the light spot on the optical recording medium 101 based on the lead-in identifier LB, and outputs a position specifying signal LI.

The position specifying signal LI is input to the transfer controller 507. Further, an operation command signal md for sending an optical pickup to the first lead-in unit 104a is input from the command unit 508 to the transfer controller 507. Transfer controller 50
At 7, a rotation command TD is sent to the transfer motor 509 based on the position specifying signal LI and the operation command signal md. As a result, the transfer motor 509 causes the optical pickup 510
Is transported in the radial direction of the optical recording medium 101.

As described above, the optical disk device according to the present embodiment includes the photodetector 502 and the pit detector 505.
(Pit detecting means) and a lead-in detector 506 (lead-in detecting means).

Next, a specific operation of the address bit detector 503 will be described with reference to FIG. In FIG. 6, the horizontal axis represents time. Reproduction signal s of photodetector 502
Is a waveform obtained by reproducing the clock pit, the first wobble pit, the second wobble pit, and the address pit on the optical recording medium 101. When the light spot passes through the place where the pit exists, the reflected light is scattered by the pit and the amount of light received by the photodetector 502 decreases, so that the reproduced signal s has a downwardly convex waveform at the place of the pit. This is shown in the reproduction signal s in FIG.

First, the position of the clock pit in the reproduced signal s is detected. This is because no pits are arranged in a predetermined section on the optical recording medium 101 in a predetermined section ahead of the clock pit (an area where the clock pit is reproduced before the clock pit is reproduced based on the scanning direction of the light spot). And using known methods. Thereby,
The reproduction timing T1 of the clock pit can be easily detected. As a result of detecting T1, a timing signal CG is generated.

Next, a reproduced clock signal CLK synchronized with the reproduced signal s is generated. This can be easily generated by using a PLL circuit or the like that operates in synchronization with the reproduced signal s of the clock pit. Next, the reproduction timing signal AG indicating the reproduction timing T2 of the address pit 204 is converted into the reproduction timing signal CG of the clock pit and the reproduction clock signal C.
Generated based on LK.

Next, the reproduction signal s is converted to the reproduction timing signal A.
By detecting at the timing of G, the reproduction signal AB is generated. When the pit of the address pit 204 exists, the reproduction signal AB is in the “H” state, and when the pit of the address pit 204 does not exist, the reproduction signal AB
Becomes "L" state.

Finally, the latch signal LP is the reproduction signal A
B is a signal indicating that B is determined, and is generated as a signal delayed by a predetermined time (T3-T2) from the timing signal AG.

Thus, the address pit detector 5
03, a detection signal AB indicating the presence or absence of an address pit on the optical recording medium 101 and a latch signal L of the detection signal AB
Outputs P.

Next, a specific configuration of the lead-in bit detector 504 will be described. FIG. 7 shows a specific configuration of the lead-in bit detector 504.

The 3-bit shift register 7 in FIG.
01 captures the state of the detection signal AB of the address bit detector 503 at the timing of the latch signal LP. In the 15-bit shift register 702, the information of the third bit of the shift register 701 is stored in the latch signal LP.
Capture at the timing. The error detector 703 performs an error check on the 15-bit data captured by the shift register 702. As a result, when there is no error, the latch signal L is output. The latch signal L is
The signal is input to the latch circuit 704. The latch circuit 704 takes in the contents of the shift register 701 according to the latch signal L and outputs it as a 3-bit lead-in identifier LB.

Next, in the apparatus shown in FIG. 5, the lead-in identifier LB inputted from the lead-in bit detector 504
The operation by which the lead-in detector 506 specifies the position of the light spot on the optical recording medium 101 will now be described.

When the three-bit value of the lead-in identifier LB is [HHH], the optical recording medium 10 shown in FIG.
It is determined that a light spot is present on the innermost peripheral portion 401 on the first position. The 3-bit value of the lead-in identifier LB is [HHL]
When it is determined that there is a light spot in the first lead-in section 104a. When the 3-bit value of the lead-in identifier LB is [HLL], it is determined that a light spot exists in the second lead-in unit 104b. If the 3-bit value of the lead-in identifier LB is [LLL], the outer periphery of the lead-in unit 104, that is, the data unit 4
It is determined that there is a light spot at 02. In this way, the lead-in detector 506 uses the lead-in identifier L
Using B, the position of the light spot on the optical recording medium 101 is specified.

The operation when the lead-in section 104 is detected in the optical disk device configured as described above will be described in detail.

First, consider a case where a light spot on the optical recording medium 101 exists on the data section 402. At this time,
The lead-in identifier LB detected by the lead-in bit detector 504 has a value of [LLL]. In the lead-in detector 506, the state of the lead-in identifier LB is [LL
L], it is determined that the light spot on the optical recording medium 101 exists on the data section 402.

Next, consider a case where a light spot on the optical recording medium 101 exists on the first lead-in portion 104a. At this time, the lead-in identifier LB detected by the lead-in bit detector 504 has a value of [HHL].
Since the state of the lead-in identifier LB is [HHL], the lead-in detector 506 determines that the light spot on the optical recording medium 101 exists on the first lead-in section 104a.

Thus, the lead-in section 104 can be detected. Therefore, by using the above configuration, the optical pickup 5
An optical disk apparatus capable of moving the optical disk 10 can be configured. The operation of such an optical disk device will be described below.

First, when a lead-in detection command is issued from the command unit 508, the transfer controller 507 sends the optical pickup to the inner or outer circumference according to the detection result of the lead-in detector 506. That is, the lead-in detector 506
If the result of the detection is the data section 406, the optical pickup 5
10 is moved to the inner circumference, and stops the transfer when the second lead-in section 104b is detected. When the detection result of the lead-in detector 506 is the innermost peripheral portion 401, the optical pickup 510 is moved to the outer periphery, and stops moving when the first lead-in portion 104a is detected. If the detection result of the lead-in detector 506 is the first or second lead-in section 104a, 104b, the operation is stopped as it is. In this manner, the optical pickup 510 can be accurately moved to the lead-in section 104.

As described above, the optical disk device according to the present embodiment detects the reflected light from the optical recording medium and outputs a detection signal, and the optical recording medium based on the detection signal of the photodetector 502. By detecting a predetermined pit from a pit detector 505 for detecting the upper pit and a pit detection signal of the pit detector 505, the lead-in section 10
4, a lead-in detector 506 for detecting
2 and a transfer motor 509 for transferring the optical pickup 510 to the inner or outer circumference of the optical recording medium. And the transfer motor 509
To move the optical pickup 510 to the inner circumference or the outer circumference, and stop the transport according to the detection signal of the lead-in detection unit 506.

In particular, the lead-in section 1 of the optical recording medium 101
04 is divided into two and has unique lead-in identifiers 301a and 301b, so that access from the outer periphery is transferred to the second lead-in unit 104b and access from the inner periphery is transferred to the first lead-in unit 104a. Can be
Transfer time can be reduced.

In a normal optical recording medium, the lead-in information of the lead-in section is often recorded in a multiplexed manner in order to enhance the reliability, and it is difficult to attach the unique lead-in identifiers 301a and 301b to each of them. This is very effective in accessing the lead-in section.

The output signal of the photodetector may be converted into a digital signal by an AD (analog-digital) converter, and the same operation as that of the pit detector or lead-in detector may be performed by a microprocessor or the like. In this case, needless to say, the same effect can be obtained.

[0076]

According to the optical recording medium of the present invention, the pits of at least one servo area among the plurality of servo areas existing in the circumferential direction are different only at the boundary of the lead-in portion. Even when the control is not operating, it is possible to easily detect the lead-in portion on the optical recording medium.

Further, the optical disk apparatus of the present invention is configured to use the optical recording medium having the above configuration, and includes a pit detector for detecting pits on the optical recording medium, and a lead-in section from a pit detection signal of the pit detector. Is provided, a lead-in portion on the optical recording medium can be easily detected.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an optical recording medium according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a segment of the optical recording medium according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of address information of an optical recording medium according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of an address pit near a lead-in portion of the optical recording medium according to the first embodiment of the present invention;

FIG. 5 is a block diagram illustrating a configuration of an optical disk device according to a second embodiment of the present invention.

FIG. 6 is a waveform chart for explaining the operation of the optical disc device according to the second embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a lead-in bit detector of the optical disc device according to the second embodiment of the present invention.

FIG. 8 is a diagram showing a configuration of a conventional optical recording medium.

FIG. 9 is a diagram showing the configuration of a segment of a conventional optical recording medium.

FIG. 10 is a diagram showing a configuration of address information of a conventional optical recording medium.

[Explanation of symbols]

 101 optical recording medium 102 track center line 103 segment 104 lead-in part 104a first lead-in part 104b second lead-in part 104 lead-in part 205 servo area 206 data area 301a, 301b lead-in identifier 401 innermost peripheral part 402 Data part 501 Objective lens 502 Photodetector 503 Address bit detector 504 Lead-in bit detector 505 Pit detector 506 Lead-in detector 507 Transfer controller 508 Commander 509 Transfer motor

Claims (6)

[Claims] 1. A servo area having a plurality of optically readable pits and a plurality of data areas for recording or reproducing data are alternately arranged in a circumferential direction, and a read area is provided on an inner peripheral portion. In the optical recording medium in which the lead-in part is arranged, in the data area of the lead-in part, lead-in information is recorded by optically readable pits; An optical recording medium, wherein the arrangement of pits in at least one of the plurality of servo areas is different. 2. The lead-in section is divided in a radial direction to form a plurality of divided lead-in sections, and at least one piece of common lead-in information is stored in a data area of each of the plurality of divided lead-in sections. The pit arrangement in at least one of the plurality of servo areas present in the circumferential direction is different from each other in two adjacent divided lead-in sections which are recorded and adjacent to each other. The optical recording medium according to the above. 3. The arrangement of pits in at least one servo area of at least one of the plurality of servo areas in a circumferential direction is different from each other between an inner peripheral part of the lead-in part and the lead-in part. The optical recording medium according to claim 1, wherein 4. In each divided lead-in area, at least one pit in at least one servo area is arranged such that pits are present substantially continuously in the radial direction. 4. The optical recording medium according to claim 2, wherein the pit arrangement of the at least one servo area differs substantially in the radial direction at the boundary of the in-portion. 5. A photodetector for detecting a reflected light from the optical recording medium according to claim 1 and outputting a photodetection signal, and a pit detection for detecting a pit on the optical recording medium from the photodetection signal. An optical disc device comprising: means for detecting a lead-in portion by detecting presence or absence of a predetermined pit from a pit detection signal of the pit detection means. 6. A photodetector for detecting reflected light from the optical recording medium according to claim 1 and outputting a photodetection signal, and a pit for detecting a pit on the optical recording medium from the photodetection signal. Detection means, lead-in detection means for detecting a lead-in portion by detecting a predetermined pit from a pit detection signal of the pit detection means, an optical pickup equipped with the photodetector, and the optical pickup Transport means for transporting to the inner circumference or outer circumference of the optical recording medium,
An optical disc apparatus, wherein the optical pickup is transferred to the inner or outer circumference by the transfer means, and the transfer is stopped according to a detection signal of the lead-in detection means.