JPH02227878A - Information recorder and information recording medium - Google Patents

Abstract

PURPOSE:To enlarge a recording capacity, to speed up an access time, and simultaneously, to stably record management information by forming a recording pit at a specific interval, respectively, at an internal side and an external side from a sertain prescribed radius position, recording storage information at the internal side, and recording the management information at the external side. CONSTITUTION:The pit is formed at the same interval so as to fix a linear density at the internal side from a certain prescribed radius position of a disk information recording medium, and the information is recorded in gradually widening the pit interval according to the radius position according as the radius position goes to the external side at the external side from the prescribed radius position. The storage information is recorded at the internal side from the prescribed radius position, and the management information to manage the storage information is recorded at the external side from the prescribed radius position. Thus, the recording capacity is held large, simultaneously, the high-speed access can be executed, simultaneously, the stable recording can be executed even in an outer circumferential part, and the outer circumferential part can be used as the recording area of the management information to require a higher reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an information recording device that records information optically, for example, and an information recording medium used in this information recording device.

(Prior Art) Conventionally, in an information recording/reproducing apparatus such as an optical disk device that records or reproduces information on an information recording medium such as a recordable or erasable optical disk, a linear motor is used in the radial direction of the optical disk. By irradiating the optical head, which moves linearly, with more light, information is recorded or reproduced.

In such optical disk devices, in order to stabilize information recording and reproduction and further shorten access time, the CAV method (CAV method) in which the rotational speed of the optical disk is constant is generally used.
Constant A ngularVeloclLy
The recording method (method) is adopted.

In the case of this CAV system, the recording or reproduction clock, that is, the frequency of information modulation and demodulation, is constant. Therefore,
The recording density of information decreases toward the outer circumference of the optical disc.

On the other hand, in order to achieve high recording density, the number of revolutions of the optical disc is changed as the optical head moves from the inside to the outside of the optical disc, and the linear velocity of the optical disc relative to the optical head is kept constant, thereby keeping the recording density constant. The CLV method (Constant L 1near
There are some that adopt the Veloc1ty method). This recording method has the advantage of increasing the recording capacity per optical disk, but since the rotational speed of the optical disk is varied, a waiting time is required until the rotational speed reaches the target value, and the access time is becomes longer.

Therefore, a system has been developed that uses a constant linear density method in which the rotational speed of the optical disk is kept constant and the data transfer frequency during recording and reproduction is varied to keep the linear density on the optical disk constant. .

(Problem 8 to be solved by the invention) However, in the constant linear density method, which is a recording method that eliminates the drawbacks of the conventional CAV method and CLV method, the line density increases toward the outer periphery of the information recording medium. As the speed increases, it is necessary to increase the frequency of the information transfer lock accordingly, and for this reason, when accessing the outer periphery of the information recording medium, the operating margin of the control circuit that controls the information recording operation is small. In addition, since the recording laser power margin becomes smaller and the information recording conditions become stricter, there is a problem that it is not suitable for recording management information that requires higher reliability. Another problem is that when information recording media employing various recording methods coexist, it is not possible to identify which type of method is used for recording and reproduction. The present invention was made to solve the above problems, and the CAV
The recording capacity is larger than that of the CLV recording method, the access time is sufficiently faster than that of the CLV recording method, and stable recording is possible on the outer periphery of the information recording medium, making it suitable for recording management information. It is an object of the present invention to provide an information recording device and an information recording medium that employ a recording method that can be used as an area, and that can further identify the type of the information recording medium.

[Structure of the Invention] (Means for Solving the Problems) The information recording device of the present invention includes a rotating means for rotating a disc-shaped information recording medium at a constant speed, and a rotating means for rotating a disc-shaped information recording medium at a constant speed. a recording means for recording information by forming recording pits on an information recording medium; a detection means for detecting a radial position at which the recording means faces the information recording medium; When it is detected that the information recording medium is facing inward from a certain predetermined radial position, recording pits are formed at a certain predetermined interval, and the recording means control means for controlling the recording means to form recording pits while gradually increasing the predetermined interval as the radial position of the information recording medium moves outward; Equipped with
The information storage medium is characterized in that storage information is recorded inside the predetermined radial position of the information recording medium, and management information for managing the storage information is recorded outside the predetermined radial position.

Further, the information recording medium of the present invention is rotated at a constant speed,
In a disc-shaped information recording medium on which information is recorded, an area inside a certain predetermined radial position and in which recording pits are formed at a certain predetermined interval is defined as a storage information area, and It is characterized in that an area on the outside where recording pits are formed with the predetermined interval gradually increasing as the radial position moves outward is set as a management information area for managing the stored information.

Furthermore, the information recording medium of the present invention is a disc-shaped information recording medium that is rotated at a constant speed and on which information is recorded, and recording pits are formed at a predetermined interval inside a certain predetermined radial position. , recording pits are formed outside the predetermined radial position while gradually increasing the predetermined interval as the radial position moves outward, and identification information of the information recording medium is recorded at a specific position on the information recording medium. It is characterized by being

(Function) The present invention forms pits at the same intervals so that the linear density is constant inside a certain radial position of a disk-shaped information recording medium, and at radial positions outside of the above-mentioned prescribed radial position. Information is recorded while gradually widening the pit interval according to the radial position as the radial position moves outward, and the stored information is stored inside the predetermined radial position and the information is stored outside the predetermined radial position. Management information for managing the above storage information is recorded. This allows high-speed access while maintaining a large recording capacity, and allows stable recording even on the outer periphery of the information recording medium.
This outer peripheral portion can be used as a recording area for management information that requires higher reliability.

In addition, by referring to the identification information provided at a predetermined position on the information recording medium, it is possible to determine the recording method used in the information recording medium, thereby making it possible to perform recording and playback that is compatible with the information recording medium. It can be done automatically. It has become a thing.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration of an optical disk device as an information recording device according to the present invention. The optical disc 1, which serves as an information recording medium used in this optical disc device, is made of a circular substrate made of glass or plastic, for example, and coated with a donut-shaped metal coating layer such as tellurium or bismuth on the surface of the substrate. can be,
A notch, that is, a reference mark 11, is provided near the center of the metal coating layer.

A concentric or spiral track for recording information is formed on the optical disk 1, and this track is divided into 256 sectors from 0 to 255 with the reference mark 11 as 0. . As described above, this optical disc 1 is formatted by any one of the recording methods, such as the CAV method, the CLV method, the constant linear density method, or the method according to the present invention (details will be described later). Also, a predetermined position (
identification information recording area), the optical disc 1 is CAV
Identification information indicating which recording method is used for formatting, the CLV method, the constant linear density method, or the method according to the present invention, that is, the method to be used for recording or reproduction is recorded. The reason why the identification information recording area is provided at a predetermined position on the innermost circumference side is to eliminate the influence of the recording density of the recording pits due to the differences in each recording method mentioned above.
This is to make it possible to read out identification information recorded using any recording method. In addition, examples of identification information include Eva,
"00" for CAV method, ro for CLv method
IJ, rlOJ in the case of the constant linear density method, and "11" in the case of the method according to the present invention are recorded.

Further, on the optical disc 1, as shown in FIG. 11, variable length information is recorded over a plurality of blocks. A block header (header information) A consisting of a block number, track number, etc. is recorded at the start position of the block. Furthermore, if each block does not end at the sector switching position, a block gap is provided so that each block always starts at the sector switching position.

Such an optical disk 1 is attached to a spindle motor (rotating means) 2 and rotated at a predetermined number of rotations, and the rotation is controlled by a control signal S1 output from a spindle motor control circuit 3. Starting, stopping, etc. are controlled.

The spindle motor control circuit 3 receives a reference frequency Fg output from a frequency oscillator (not shown) and a rotation pulse signal S output from the spindle motor 2 and corresponding to its rotation speed.
A phase comparator 31 that inputs 2 and performs phase comparison, a low-pass filter 32 that removes high frequency components of the output signal of this phase comparator 31, and a low-pass filter 32 that amplifies the output signal of this low-pass filter 32 and transmits it to the spindle motor 2. and a motor driver 33 that rotationally drives the spindle motor 2 by supplying the motor. Then, in accordance with the control signal S3 from the control circuit 4, a control signal S1 accurately synchronized with the reference frequency Fs is output. This control signal S
1 allows the spindle motor 2 to rotate at an accurately constant rotation speed.

The control circuit (detection means, control means) 4 is constituted by, for example, a microcomputer, and controls the rotation of the spindle motor 2 as well as various other controls to be described later.

An optical head (recording means) 5 is provided on the bottom side of the optical disc 1.
is installed. This optical head 5 records or reproduces information on the optical disc 1, and is a well-known astigmatic head consisting of a semiconductor laser oscillator 6, a collimator lens 7, a beam splitter 8, an objective lens 9, a cylindrical lens 10, and a convex lens 11. It is composed of an aberrational optical system 12, photodetectors 13, 14, lens actuators 15, 16, and the like. This optical head 5 has a moving mechanism (not shown) configured by, for example, a linear motor or the like.
It is disposed so as to be movable in the radial direction of the optical disc 1, and is moved to a target track for recording or reproduction according to instructions from the control circuit 4.

The semiconductor laser oscillator 6 generates a diverging laser beam according to the drive signal S4 from the optical output control circuit 2°. A laser beam whose light intensity is modulated is generated, and when reading and reproducing information from the optical disc 1, a laser beam having a constant light intensity is generated.

A diverging laser beam generated from a semiconductor laser oscillator 6 is converted into a parallel beam by a collimator lens 7 and guided to a beam splitter 8 .

The laser light guided to the beam splitter 8 passes through the beam splitter 8 and enters an objective lens 9, and is focused by the objective lens 9 toward the film 8 of the optical disc 1.

The objective lens 9 is supported movably in its forward axis direction by a lens actuator 15 as a lens drive mechanism. The focused laser beam that has passed through the objective lens 9 is then moved in the optical axis direction by a focus servo signal S5 from a focus servo circuit (not shown) inside the signal processing circuit 17, and is directed onto the surface of the optical disk 1. The beam is projected so that the minimum beam spot is formed on the surface of the recording film of the optical disc 1. In this state, the objective lens 9 is in a focused state.

The objective lens 9 is also movable in a direction perpendicular to the optical axis by a lens actuator 16.
The objective lens 9 is moved in a direction perpendicular to the optical axis by a tracking servo signal S6 from a tracking servo circuit (not shown) inside the signal processing circuit 17. Then, the focused laser beam that passes through the objective lens 9 is projected onto the surface of the recording film of the optical disc 1, and is irradiated onto the recording tracks formed on the surface of the recording film of the optical disc 1. There is. In this state, the objective lens 9 is in a matching track state. In the focused point and focused track state, information can be written and read.

By the way, the diverging laser beam reflected from the optical disk 1 is converted into a parallel beam by the objective lens 9 when it is focused, and is returned to the beam splitter 8 again. and,
The beam is reflected by the beam splitter 8, and an astigmatism optical system 12 consisting of a cylindrical lens lO and a convex lens 11
is guided onto the photodetector 13 to form an image, and a focus shift appears as a change in shape, and a tracking shift appears as a shift in the imaging position.

The photodetector 13 includes four photodetection cells (not shown) that convert the light imaged by the astigmatism optical system 12 into electrical signals. The signal output from this photodetector 13 is supplied to a signal processing circuit 17. In the signal processing circuit 17, a focus servo circuit (not shown) inputs a signal from the photodetector 13, generates a focus servo signal S5, and supplies it to the actuator 15, thereby forming a focus servo circuit. There is. Further, in a tracking servo circuit (not shown), a tracking servo signal S6 is generated by inputting a signal from the photodetector 13, and is supplied to the actuator 16, thereby forming a tracking servo loop. Furthermore, the reproduction signal S7 outputted by the signal processing circuit 17 indicates information recorded on the optical disc 1, and is transmitted to the data demodulation circuit 40.
It is now sent to .

The data demodulation circuit 40 demodulates the reproduced signal S7 from the signal processing circuit 17 and outputs it to the control signal decoding and removal circuit 41. The control signal decoding and removing circuit 41 detects and removes synchronization codes and the like added during recording, so that only the recorded data can be retrieved. The extracted data is then supplied to a deinterleaving circuit 42. The deinterleaving circuit 42 performs interleaving to improve the possibility of error correction during recording and restores rearranged data to its original state. The output of this deinterleaving circuit 42 is supplied to an error correction circuit 43. The error correction circuit 43 corrects errors of one or more bits in the deinterleaved data. The reproduced data free of errors due to the correction in the error correction circuit 43 is supplied to the buffer memory 44, and is further outputted to the outside as a reproduced signal S8 via an interface circuit 45 that transfers data.

Further, a light emitting port opposite to the light emitting port for recording or reproducing laser light of the semiconductor laser oscillator 6 is provided.
When the photodetector 14 configured with a photoelectric conversion element such as a photodiode is irradiated with monitor light from the semiconductor laser oscillator 6, it converts the monitor light into an electrical signal (photocurrent), and converts the monitor light into an electric signal (photocurrent). The output signal is supplied to the optical output control circuit 20 as an optical output monitor signal s9. The optical output control circuit 20 includes a semiconductor laser oscillator 6
The optical output of the semiconductor laser oscillator 6 is controlled to be kept constant by inputting the optical output monitor signal S9 outputted by the semiconductor laser oscillator 6 and performing feedback control. amplifier 2
1, the photodetector 14 converts the optical signal S9 into an optical signal and outputs the optical output monitor signal S9 as an electrical signal.
The received light intensity is converted into a voltage signal according to the optical output of the semiconductor laser oscillator 6 and amplified.
It is intended to supply

This error amplifier 22 uses the output signal of the amplifier 21 as one input, and uses the reference voltage Vs generated by a constant voltage source (not shown) as the other input, compares these two types of pressure, and amplifies the difference to make an error. It is output as a signal S10. The reference voltage Vs is a constant voltage for obtaining the optical output necessary for reproduction, and the output voltage of the amplifier 21 is set to the reference voltage Vs.
Due to feedback control performed to bring it closer to s,
A constant optical output can be obtained from the semiconductor laser oscillator 6. Error signal 3.10 from error amplifier 22
is supplied to the driver 23.

As shown in FIG. 2, the driver 28 is composed of two transistors Tri and Tr2 and resistors R1, R2, and R3. A data modulation circuit 55 to be described later
, a recording pulse signal S1 corresponding to the data to be recorded.
1 is supplied to the base of the transistor Tr2, so that optical output for recording is output from the semiconductor laser oscillator 6. Furthermore, during playback, the error signal SIO output from the error amplifier °22 is input to the base of the transistor Tri of the driver 23, and during recording, the voltage value manually input during the previous playback is input to a sample-hold circuit (not shown). The voltage signal held by the sensor is input manually.

The interface circuit 50 is for receiving and receiving recording data S12 supplied from the outside, and the output of this interface circuit 50 is supplied to a buffer memory 51. The buffer memory 51 stores recording data from the interface circuit 50. The output of this buffer memory 51 is supplied to a correction code addition circuit 52, a redundancy code for making correction possible is added thereto, and the output is supplied to an interleaving circuit 53. This interleaving circuit 53 rearranges data so that the recording positions of a series of data are scattered in order to improve the possibility of correction when a burst error occurs. The output of this interleaving circuit 53 is supplied to a control signal adding circuit 54. This control signal addition circuit 54. is for adding a control code such as a synchronization code to the recorded data rearranged in the interleave circuit 53, and its output is supplied to the data modulation circuit 55.

The data modulation circuit 55 digitally modulates the recording data into a signal suitable for recording. Digital modulation in the data modulation circuit 55 is performed by referring to a ROM (not shown), and outputs a recording pulse signal Sll as serial data via a register (not shown). This recording pulse signal Sll is supplied to the driver 23, which drives the semiconductor laser oscillator 6 to record information on the optical disc 1, as described above.

The operations of the buffer memory 51, correction code addition circuit 52, interleave circuit 53, control signal addition circuit 54, and data modulation circuit 55 are performed in synchronization with the data transfer lock CKI. This data transfer lock CKI is generated by dividing the output of an oscillator 60, which oscillates at a constant frequency, into a predetermined frequency by a variable frequency dividing circuit 61.

The variable frequency divider circuit (control means) 61 determines the frequency division ratio of the constant frequency clock signal outputted by the oscillator 60 based on the setting data S13 outputted by the control circuit 4, and outputs it as a data transfer lock CKI. It looks like this. This setting data S13 is stored in advance in a conversion table configured in a ROM (not shown) provided inside the control circuit 4 in correspondence with the track number, block number, etc. as address information of the optical disc 1. There is.

In the above conversion table, for example, as shown in FIG. 3, the frequency of the data transfer lock CKI changes in a stepped manner in proportion to the radial position of the optical disc 1 toward the outer circumference, that is, in proportion to the increase in track number. , and at a certain radial position n'
Setting data S13 is stored from which a characteristic line G3 having a constant frequency can be obtained.

Incidentally, the characteristic line G1 shown in FIG. 3 shows the characteristics of the data transfer lock in the CAV system. As shown in the figure, data is recorded at a constant frequency f regardless of the radial position of the optical disc 1.

Therefore, as shown in FIG. 4, on a track with radius r, pits are formed in the order of agsal, a2, etc. at a constant pit interval g (a certain predetermined interval), and with a radius of 2
On the track ", the rotational speed of the optical disc 1, that is, the angular velocity, is constant, so pits are formed in the order of bo%b1%b2... with a pit interval of 2g. Therefore,
The recording capacity per track is the same whether at radial position r or 2r.

Further, a characteristic line G2 shows the characteristics of data transfer lock in the constant linear density method. The frequency of this data transfer lock increases linearly in proportion to the radial position of the optical disc 1. In other words, the data transfer lock frequency is f at the radius of the optical disc 1, but it becomes 2f, which is twice the frequency, at the position where the radius is 2'. On the track with the radius ", aOSal, al・
..., pits are formed in the order of pit spacing g, but on a track with a radius of 2'', the data transfer lock frequency is doubled to 2f, and boScl, bl c2, b2
. . . Pits are formed at a pit interval g in this order. Therefore, the recording density (pit interval) is constant regardless of whether the optical disc 1 is on the inner or outer circumference side. However, as mentioned above, this constant recording density recording method has the disadvantage that the recording conditions become stricter at the outer periphery of the optical disc 1, and the reliability of the recorded data is lower than at the inner periphery. be.

On the other hand, a characteristic line G3 shows the characteristics of the data transfer lock according to the present invention, and the frequency of this data transfer lock is such that the optical disc 1
The frequency increases stepwise in proportion to the radial position, and the frequency nf is constant at radial positions outside the predetermined radial position nr. Therefore, as shown in FIG. 4, on a track with radius ", pits are formed in the order of aOs al , al . . . with pit spacing g in the same way as above, and on a track with radius nr, do s ct , , d2, . . . , pits are formed in the order of pit spacing g.In other words, the range from this radius to 2” is recorded by the constant linear density method, and the recording density is constant.

Note that since the data transfer lock changes in a stepwise manner, strictly speaking, the recording density on each track cannot be said to be constant, but as will be explained later, the amount of change in frequency in one step is minute. Therefore, it can be said that the route density is constant.

On the other hand, at a radius position larger than the radius nr, a pit is formed due to the data transfer lock of the constant frequency port f.

Therefore, on a track with radius nr, (10% d
Pit is formed in the order of l '2..., but
On a track with a radius of 2'', pits are formed in the order bO, el, e2, etc., and the recording density decreases as the radial position moves outward.In other words, a range larger than this radius nr is recorded using the CAV method. Since pits are formed, the recording capacity per track becomes constant.

By controlling the data transfer lock as shown in the above characteristic line G3, the recording capacity of the first disk 1 becomes as shown in FIG. 5. In other words, the storage capacity when the radius r to 2'' of the optical disk 1 rotated at a constant rotation speed is recorded using the C'' AVAV method at the data transfer lock frequency f1, is expressed by the area S1 surrounded by the rectangle tuvw. Can be done. On the other hand, when recording is performed using the constant linear density method, the data transfer lock changes from fl to 2f as the radial position changes from "to 2". Therefore, the area of the triangle twz (S2+93) is In other words, the recording capacity of half of the surface 81S1 increases, and the total recording capacity increases by 1.5 times.However, as mentioned above, the recording conditions become stricter when the radial position is on the outer circumferential side. Constant frequency 1.5f on the outer circumferential side from the position of radius 1.5r,
When recording is performed using the CAV method, the area of the trapezoid twyx is S? compared to when recording using the CAV method. The recording capacity will increase by that amount. That is, when using the data transfer lock of the characteristic line G3 according to the present invention, the recording capacity is 1.375 times that of the CAV method.

It goes without saying that the recording capacity changes depending on the radial position at which the frequency of the data transfer lock is kept constant. Table 1 shows the calculation results of the change in recording capacity with respect to the radial position where the data transfer lock is constant, and FIG. 6 shows the relationship between the recording capacity and the radial position where the data transfer lock is constant.

In addition, as shown in Figure 3, in the radius range from r to n, the data transfer lock does not change linearly depending on the radial position, but changes stepwise. This configuration has the advantage of facilitating the design of the variable frequency divider circuit 61.In order to change the data transfer lock stepwise, the data transfer lock is changed for each predetermined track number. The setting data 813 in which the
It is prepared in a conversion table formed in OM. The change in frequency per step in this stepwise change is determined as follows.

Generally, the reproduction signal from the optical disc 1 is not synchronized with the pig transfer lock CKI, and therefore, the data demodulation circuit 40, control signal decoding and removal circuit 41, data demodulation circuit 42, error correction circuit 43, buffer The clock CK2 supplied to the memory 44 is generated by separating the clock from the self-clock included in the reproduced digital modulation signal. This clock separation is performed by a PL as a clock separation circuit included in the data demodulation circuit 40.
L (phase locked loop) control circuit.

The basic configuration of this PLL control circuit, as shown in FIG. is starting to form.

Generally, the binary signal of the reproduced signal from the optical disc 1 is
The digitally modulated signal is digitally modulated, and the binary signal is input to a phase comparator 71 in order to separate the self-clock signal included in this digitally modulated signal. For this reason, only when an input pulse is input, the input phase θi and the output phase θ
The phase comparison characteristic in this case is as shown in FIG.

In this way, since the phase with the output is compared only when the edge of the input pulse arrives, the frequency at which the phase is locked is the 8th
As shown in the figure, there are multiple locations. Therefore, in practice, as shown in FIG. 9, the PLL control circuit is configured using a frequency abnormality detection circuit 86 so that correct clock separation from the digital modulation signal is performed during reproduction.

In FIG. 9, when accessing address parts at different radial positions, a phase loop is activated by inputting the transfer lock frequency θi' according to the address to perform a comparison at the frequency of fo, and the access When this is done, the output switching circuit 83 switches from the phase comparator 82 to the phase comparator 81 to perform phase locking, thereby separating the clocks correctly and making it possible to perform address decoding, etc. ing.

At this time, since recording is performed while changing the data transfer lock CKI in a stepwise manner, the frequency differs at the switching portion. For this reason, if the difference in frequency of one of the stairs is large, if a track is accessed that is different from the predetermined data transfer lock frequency at the time of access, correct phase lock will not be performed and the address will not be decoded. become unable to do so. Therefore, by keeping the frequency difference smaller than the data decoding limit of digital modulation using adjacent data transfer lock frequencies, addresses can be correctly decoded even when accessing an adjacent data transfer lock area that is different from the specified one. This makes it possible to access the target address again.

As an example, the data decoding limit in 2-7 code modulation, which is one of the digital modulation methods, is ±6.25%. Therefore, in this case, there will be no problem if the frequency abnormality detection is set to 6% or less and the change in one step of the data transfer lock is smaller than this.

Therefore, it is sufficient to change the data transfer lock by about 1% per step, which makes it easy to specify the data transfer lock and also solves access problems. It has become a thing.

Next, the margin of the recording laser power with respect to the radial position of the optical disc 1 will be explained. In heat mode recording, in which recording pits are formed using the thermal energy of a focused laser beam, the recording conditions are such that the energy density of the focused spot is constant regardless of the radial position of the optical disc 1, and the laser beam is The product of the optical output P (Vl; watts) and the pulse width Tp (S: seconds), that is, the energy J-PX
It is determined from Tp and the sensitivity of the optical disc 1.

At this time, while there is a limit to the size of the laser light output,
Recording as fast as possible is required. In this case, if the recording range is twice as large in radial position, the linear velocity will be twice as high on the outer circumference as on the inner circumference under a constant rotational speed, and if the recording conditions are the same on the inner and outer circumferences, then The recording energy is constant, and in order to remove the influence of linear velocity, the inner circumference Jl-plxT
pl, J2- (2P1)X (T
Although it is desirable to set the value to pl/2)-Jl, it is difficult in reality due to laser power limitations. For this reason, the recording conditions for a constant linear density method with a constant rotational speed have become extremely difficult.

FIG. 10 shows the characteristics of the recording laser power margin in the recording method according to the present invention. That is, optical disc 1
The recording laser power margin for the radial position is the range surrounded by straight line a and polygonal line C. In the figure, the recording pulse width Tp is assumed to be constant regardless of the radial position of the optical disc 1. Also, at the innermost radius of the optical disc 1, determine the recording pulse width Tp, optimize the recording pit interval, etc., perform recording by changing the recording laser power, and then perform playback. The lower limit of possible recording laser power is p2, and the upper limit is I)I.

Also, the lower limit of the recording laser power at each radial position is M!
il a, the radius r of the inner circumference is p2, and the radius of the outer circumference is 2.
", and p4, and p-i > p2. This is because the linear velocity is high (twice as much) at the outer periphery, and a large recording laser power is required due to the influence of this linear velocity.

Further, the upper limit of the recording laser power at each radial position is indicated by a polygonal line C. Note that the point vab in the figure indicates the upper limit of the recording laser power in the case of the constant recording density method. The constant recording density method and the recording method according to the present invention will be explained below in comparison. In the case of the constant recording density method, the upper limit of the recording laser power is I)1 for the inner radius r, and p3 for the outer radius 2.
1) 3<p+. The reason for this is that under a constant recording pulse width Tp, as the recording laser power is increased, the recording pits that are formed will become larger toward the outer periphery. Margins are getting smaller. From the viewpoint of long-term stability and reliability of the device, it is desirable that the margin of this recording laser power be as wide as possible. Further, it is desirable that it be constant without being affected by the radial position of the optical disc 1.

Therefore, as mentioned above, by recording with the CAV method on the outer circumferential side from a radius of 1.5r, for example, the upper limit of the recording laser power indicated by the dotted line changes as shown by the bend 11c, and the recording laser power on the outer circumference changes. The power margin is much wider. That is, as the optical head 5 moves from the inner circumferential side to the outer circumferential side of the optical disc 1, the relative linear velocity between the optical head 5 and the optical disc 1 increases, but the recording pit interval also increases accordingly. This is because even if the recording pit becomes larger by increasing the recording laser power, it will not be affected easily during reproduction.

As described above, by applying the present invention, the margin of the recording laser power at the outer peripheral portion of the optical disc 1 becomes larger, so that stable recording and reproduction can be performed.
Management data such as search information that requires higher reliability (
It is suitable as a recording area for management information).

Furthermore, the optical disc 1 used in an optical disc device that employs the above recording method is formatted so that the recording density is constant on the inner circumferential side of the above-mentioned predetermined radial position, and the recording density is constant on the outer circumferential side. It is created by duplicating a recording master (not shown) that is formatted to have a constant capacity. At this time, the radial position of the optical disk 1 at which the data transfer lock should be kept constant is determined between the side that formats the optical disk 1 and the optical disk device that uses it, based on the track number. .

As explained above, according to the recording method according to the present invention,
Inside a predetermined radial position of the optical disc 1, pits are formed at the same intervals so that the linear density is constant, and outside the predetermined radial position, pits are formed according to the radial position as the radial position moves outward. Since information is recorded while gradually widening the interval (recording using the CAV method), information can be recorded at high speed without significantly reducing the recording capacity per optical disc 1 compared to the constant linear density method. It is possible to record on the optical disc 1 as well as the outside 11 of the optical disc 1.
Since it is possible to have a large margin for the recording laser power in the area, and the recording conditions are significantly relaxed, it is possible to use the outer peripheral part of the optical disc 1 as a recording area for management data that requires higher reliability. can.

In addition, an identification information recording area is provided at a predetermined position on the innermost circumference side of the optical disc 1, and the recording method in which the optical disc 1 was formatted is recorded as identification information, so that this identification information can be stored in the optical disc device. It is possible to automatically perform reading, recording, or reproduction using a method compatible with the recording method. Therefore, it is possible to prevent the occurrence of a situation where the recording method used for recording on the optical disc 1 and the recording or reproducing method used in the optical disc device do not match and information cannot be recorded or reproduced. .

In the constant recording density method, by increasing the data transfer lock CKI, the buffer memory 51, correction code addition circuit 52, interleave circuit 53, and control signal addition circuit 54 operate in synchronization with the data transfer lock CKI. However, as mentioned above, according to the present invention, the data transfer lock CKI is not increased above a predetermined frequency.
This has the effect that the operation margin of each of the circuits described above can be ensured.

Furthermore, when recording on the inner circumferential side from the predetermined radial position using the constant linear density method, the data transfer lock, which is the recording timing, is changed in a stepwise manner, and the data transfer lock changes per step. By setting the frequency to about 1% of the amount of change in frequency that is changed using the constant linear density method, it is possible to easily generate a lock for data transfer and to access a given track accurately. There is.

[Effects of the Invention] As detailed above, according to the present invention, the recording capacity can be made larger than that of the CAV recording method, the access time can be made sufficiently faster than the CLV recording method, and the information recording medium can be Provided is an information recording device and an information recording medium that employ a recording method that enables stable recording on the outer circumferential portion to provide an area suitable for recording management information, and that also allows identification of the type of information recording medium. can do.

[Brief explanation of the drawing]

The figures show one embodiment of the present invention, in which Fig. 1 is a diagram showing the schematic configuration of an optical disk device, Fig. 2 is a circuit diagram showing the configuration of the driver, and Fig. 3 is a diagram showing changes in the data transfer lock. Figure 4 is a diagram for explaining the pit interval, Figure 5 is a diagram for explaining the recording capacity of each recording method,
Fig. 6 is a diagram for explaining the relationship between the recording capacity and the radial position that keeps the data transfer lock constant, Fig. 7 is a diagram showing the basic configuration of the PLL control circuit, and Fig. 8 is the operation of the PLL control circuit. 9 is a diagram showing the configuration of a PLL control circuit as a clock separation circuit. FIG. 10 is a diagram illustrating the recording laser power margin.
FIG. 1 is a diagram showing the configuration of an optical disc. DESCRIPTION OF SYMBOLS 1... Optical disk, 2... Spindle motor (rotation means), 4... Control circuit (detection means, control means), 5
... optical head (recording means), 6 ... semiconductor laser oscillator, 9 ... objective lens, 20 ... optical output control circuit, 61 ... variable frequency division circuit (control means).

Claims (3)

[Claims] (1) A rotating means for rotating a disc-shaped information recording medium at a constant speed, and a recording means for recording information by forming recording pits on the information recording medium being rotated at a constant speed by the rotating means. , detection means for detecting a radial position where the recording means faces the information recording medium; and the detection means detects that the recording means faces inside a predetermined radial position of the information recording medium. In this case, recording pits are formed at a predetermined interval, and when it is detected that the recording means is facing outward from the predetermined radial position of the information recording medium, control means for controlling the recording means to form recording pits while gradually widening the predetermined intervals as the information recording medium moves outward, and storing information inside the predetermined radial position of the information recording medium. an information recording device, wherein management information for managing the stored information is recorded outside the predetermined radial position. (2) In a disc-shaped information recording medium that rotates at a constant speed and records information, the area inside a certain predetermined radial position and where recording pits are formed at certain predetermined intervals is called storage information. As an area,
An area outside the predetermined radial position, in which recording pits are formed while gradually increasing the predetermined interval as the radial position moves outward, is set as a management information area for managing the stored information. information recording medium. (3) In a disk-shaped information recording medium that is rotated at a constant speed and on which information is recorded, recording pits are formed at a predetermined interval inside a certain predetermined radial position, and The outside is
An information recording characterized in that recording pits are formed while gradually increasing the predetermined interval as the radial position moves outward, and identification information of the information recording medium is recorded at a specific position on the information recording medium. Medium.