JP2001209943A - Optical disk recording/reproducing device and information reading method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the read-out of the preformat address and the recording information with satisfied reproducibility from an optical disk even in the case adjacent information recording layers are irradiated by a light beam across over them due to the increase of the recording density of the optical disk and also to attain the prevention of the crosstalk between adjacent pregrooves. SOLUTION: This optical disk recording/reproducing device 100 is arranged for reading out the recording information from the optical disk 10 whereon the information is recorded based on the preformat address, and it is furnished with a light output means 6 for irradiating the optical disk 10 with the light beam L, and a photodetecting means 7 for making the detection by separating to the preformat address and recording information and the interference information according to the preformat address at the inner/outer peripheral sides adjacent to the preformat address in regard to a return light L' caused by the light beam L forming so as to reflect the information read out from this optical disk 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk recording / reproducing apparatus suitable for being applied to a writable optical disk such as a recordable optical disk (CD-R) or a rewritable optical disk (CD-RW). It relates to an information reading method.

More specifically, with respect to light detection means for detecting return light due to a light beam applied to an optical disk, detection is performed by dividing the address and recorded information and interference information by inner and outer addresses adjacent to the address. Even when the recording density of the optical disc is increased and the adjacent information recording layer is irradiated with a light beam over the optical disc, the address and the recorded information can be read from the optical disc with good reproducibility, and the cross between adjacent pregrooves can be obtained. This is to prevent talk.

[0003]

2. Description of the Related Art In recent years, writable optical disks, for example, ISO / IEC13490-, have been used as information media for editing and recording audio information and the like according to listeners' preferences.
Recordable optical disc (CD-
R) or rewritable optical disk (CD-RW)
Is often used. In these optical disks 10, as shown in FIG. 10A, a groove (hereinafter referred to as a pre-groove) 1 for guiding a light beam is formed.
A positioning method called tracking servo is adopted. The tracking servo is a mechanism for detecting the unevenness of the slopes of the lands 2 on both sides of the pre-groove 1 and positioning the optical pickup so as to properly irradiate a laser beam to a desired pre-format address.

The land slopes at both ends of the pregroove 1
As shown in FIG. 10B, it is wobbling (meandering) in a slightly sinusoidal shape in phase. The wobble signal indicating the wobble component has been subjected to FM modulation processing, and time axis information indicating a position on the optical disc 10, a recommended value of the optimum recording power of the laser light, and the like are encoded.

[0005] The time axis information and the like are stored in ATIP (Absolute
It is called Time In Pregroove information and is written as absolute time information on the disk from the start position on the inner circumference side of the signal recording area (program area) of the optical disk 10 toward the outer circumference side. This ATIP information is written at the process stage of CD-R or CD-RW. ATIP information on CD-R
Or when writing to an optical disc 10 such as a CD-RW,
A modulation method called biphase is adopted. According to this method, a pre-formed address (hereinafter, referred to as a pre-format address) depends on whether the end of the error correction information of the immediately preceding pre-format address ends at a high level or a low level, and the pre-format of the next frame is performed. The baseband modulation is performed such that the connection is performed with the format address non-inverted or the preformat address is inverted and connected.

The ATIP information includes, for example, both sides Us and Ut of the pregroove 1 between the two lands 2a and 2b shown in FIG. 10B, that is, the land 2a located on the inner peripheral side of the pregroove 1 for recording data. Are written in synchronization with the side surface Us of the land 2b and the side surface Ut of the land 2b located on the outer peripheral side thereof.

[0007] Therefore, this ATIP information is stored in land 2
A wobble signal can be read as a wobble signal by detecting the wobble formed on the a and 2b with the two light receiving elements divided in the track direction by the reflected light from the main spot 4. The wavy circle shown in FIG. 10B indicates the spot diameter of the light beam on the standard density optical disk. Part 2
The dashed-dotted circle indicates a light beam whose irradiation diameter has become relatively large due to the proportional reduction of the pre-groove accompanying the increase in the recording density of the optical disc 10. This is because there is a limit in reducing the spot diameter of the light beam without limit.

[0008] The wobble signal is transmitted from the optical disc 10 to the CD.
The center frequency is, for example, 22.05 kHz when rotated at the standard speed (CLV).
One sector of the ATIP information matches one data sector after signal recording. At the time of recording information, if a preformat address is specified, ATIP
While synchronizing the information sector and the data sector, the pregroove 1 is irradiated with a light beam having a predetermined intensity, and the information is written.

According to the conventional method, when a signal is recorded on the optical disk 10, for example, as shown by a broken line in FIG.
The return light of the main spot 4 is shown in FIG.
The light is divided and received by the photodetector 71 shown in FIG. Light detector 71
In addition, an addition signal A + D is generated by adding the light receiving signal A from the light receiving element PD1 such as a photodiode constituting the quadrant photodetector 711 and the light receiving signal D from the light receiving element PD4 in the same manner, An addition signal B + C is generated by adding the light receiving signal B from the light receiving element PD2 and the light receiving signal C from the light receiving element PD3. The light detection unit 71 extracts the wobble component by subtracting the latter addition signal B + C from the former addition signal A + D.

In this system, an RF signal (A + B + C + D) can be obtained by adding the light receiving signals A to D of the four light receiving elements PD1 to PD4 of the photodetector 711, and a two-segment photodetector can be obtained. Tracking servo control is performed using the light receiving signal E of the light receiving element PD5 712, the light receiving signal F of the light receiving element PD6, the light receiving signal G of the light receiving element PD7 of the two-divided photodetector 713, and the light receiving signal H of the light receiving element PD8.

When the return light of the main spot 4 is used, the reflectivity changes in the process of forming the pits 61 and the amount of the return light of the main spot 4 fluctuates. Light reception signal A from detection unit 71
To H to prevent the influence of light quantity fluctuations, or to use a division circuit to add the light receiving signal A of the light receiving element PD1 and the light receiving signal D of the light receiving element PD4 and the light receiving element PD2. Light receiving signal B and light receiving element PD3
By calculating the ratio of the light receiving signal C to the added value of the light receiving signal C, the influence of the fluctuation of the light amount is prevented, wobble components are extracted, and time axis information and the like are obtained. Further, in the information reading method according to the conventional example, by sampling and holding the RF signal, time axis information or the like is obtained when the power of the laser beam is reduced from the signal writing level to the signal reading level. .

[0012]

However, as the recording pitch of the lands 2a, 2b (hereinafter, also referred to as track pitch) P becomes narrower with the increase in the recording density of the optical disk 10, by-passes without any contrivance. When information is read based on the preformat address written by the phase modulation method, a light beam whose irradiation diameter becomes relatively large due to the proportional reduction of the pregroove 1 is irradiated across the adjacent pregroove 1. (Figure 1
OB).

In other words, even if the main spot 4 is a perfect circle, if the spot diameter is larger than the track pitch P, there is leakage from an adjacent track. In such a case, the possibility of occurrence of crosstalk increases. Crosstalk causes phase modulation and the like, causing jitter, and lowering the signal-to-noise ratio (S / N).

Thus, when the bi-phase signal forming the pre-format address of the read point and the bi-phase signal of another adjacent pre-format address are superimposed, the phase difference between them is large, and the There is a problem that the shorter the period, the larger the jitter.

Further, in order to obtain time axis information and the like using the return light of the main spot 4 while forming the pits 61 in the main spot 4, a high-speed AGC, a division circuit and the like are required, and the configuration becomes complicated. Would. Even when the sample and hold operation is performed, when the signal writing is performed at a speed higher than the standard speed, the amount of the return light does not cause pit formation even if the power of the laser light is changed from the signal writing level to the signal reading level. Therefore, there is a possibility that time axis information or the like cannot be read correctly.

Therefore, the present invention has solved such a conventional problem. Even if the recording density of the optical disk is increased and the adjacent information recording layer is irradiated with a light beam over the optical disk, the present invention can solve the problem. It is an object of the present invention to provide an optical disk recording / reproducing apparatus and an information reading method capable of reading out the address and the record information with good reproducibility and preventing crosstalk between adjacent pregrooves.

[0017]

An object of the present invention is to provide an optical disk recording / reproducing apparatus for recording or reproducing recording information on or from an optical disk on which information is to be recorded, based on the address formed in advance. The optical output means for irradiating the optical disk with a light beam, and the return light including the read information from the optical disk are detected separately by the address and recording information and the interference information by the inner and outer peripheral addresses adjacent to the address. The problem is solved by an optical disk recording / reproducing apparatus comprising: a light detecting unit.

According to the optical disk recording / reproducing apparatus of the present invention, when reading the recorded information from the optical disk on which the information is recorded based on the address, when the optical output means irradiates the optical disk with the light beam, The return light by the light beam which reflects the read information is detected by the light detection means separately into the address and the record information and the interference information by the inner and outer addresses adjacent to the address.

For example, return light components reflecting the preformat address and the recorded information are detected by four light receiving elements arranged vertically and horizontally at the center of the light receiving axis of the light detecting means, and each of the light receiving elements is arranged vertically in the light receiving element. Return light components reflecting interference information based on the inner and outer peripheral preformat addresses adjacent to the preformat address are detected by the other light receiving elements arranged side by side.

The output of the light detecting means is input to the signal generating means. In the signal generating means, R is determined based on the outputs of four light receiving elements arranged vertically and horizontally at the center of the light receiving axis of the light detecting means.
An F signal and a wobble signal are created, and a tracking error signal or a focus error signal is created based on the outputs of the eight light receiving elements.

Therefore, it is possible to extract only the recording information of the preformat address from which the interference information by the preformat addresses on the inner and outer sides has been removed from the read information read from the optical disk. As a result, even when the recording density of the optical disk is increased and the adjacent information recording layer is irradiated with the light beam over the optical disk, crosstalk can be prevented without impairing the tracking error detection function and the focus detection function.

An information reading method according to the present invention is a method of reading recorded information from an optical disk on which information is recorded based on the address, wherein the optical disk is irradiated with a light beam. With respect to the return light reflected from the device, the return light component reflecting the address and the recording information and the return light component reflecting the interference information by the inner and outer peripheral addresses adjacent to the address are detected separately. Is what you do.

According to the information reading method of the present invention, it is possible to extract only the recording information of the address from which the interference information by the inner and outer peripheral addresses has been removed from the read information read from the optical disk. Even when the density increases and the adjacent information recording layer is irradiated with a light beam straddling, crosstalk can be prevented without impairing the tracking error detection function and the focus detection function.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of an optical disk recording / reproducing apparatus and an information reading method according to the present invention will be described with reference to the drawings.

(1) Embodiment FIG. 1 is a perspective view showing a configuration example of an optical disc recording / reproducing apparatus 100 as an embodiment of the present invention. FIG. 2 is a block diagram showing a configuration example of the light detection means 7 and the signal generation means 9.

In this embodiment, the light detecting means for detecting the return light by the light beam applied to the optical disk is detected separately by the address and the recorded information and the interference information by the inner and outer addresses adjacent to the address. However, even when the recording density of the optical disc is increased and the adjacent information recording layer is irradiated with a light beam straddling, it is possible to read out the address and the recorded information from the optical disc with good reproducibility. This prevents crosstalk.

An optical disk recording / reproducing apparatus 100 shown in FIG.
Is an optical disk 1 based on at least a pre-formed address (hereinafter referred to as a preformat address).
It reads the recording information from 0. Of course, the recording information is recorded on the optical disk 10 in advance based on the preformat address. For example, CD-R and CD-
In the case of an optical disc 10 such as an RW, the disc-shaped substrate has a concave pre-groove 1 and a convex land 2. The recording information is written in the groove of the pre-groove 1,
The preformat address is frequency-modulated and written on the side surface of the land 2 which is also on both sides of the pregroove 1 so as to wobble.

The optical disc recording / reproducing apparatus 100 is provided with a light output means 6 for irradiating the optical disc 10 with a light beam L having a predetermined intensity. The light output means 6 is passed through an optical system 8 so that the light receiving axes thereof coincide with each other.
The return light L ′ (reflected light) from the optical disc 10 is detected separately for the address and the recorded information and the interference information based on the inner and outer addresses adjacent to the address. The read information is reflected on the return light L 'from the optical disk 10.

In this embodiment, the light detecting means 7 shown in FIG.
In order to detect a main spot of the three-beam method, at least eight light receiving elements PD1 to PD1 are divided into four parts in a radial direction and two parts in a direction perpendicular to the light receiving area.
It has PD8. These light receiving elements PD1 to PD8
Is a photodiode. The circular shape shown in FIG. 1 is the spot diameter of the return light (incident light) L ′ straddling the eight light receiving elements PD1 to PD8. Light receiving elements PD1 to PD8
Are arranged in a matrix of 2 rows × 4 columns based on the light receiving axis (incident optical axis). At the center of the light receiving axis of the light detecting means 7, four light receiving elements PD1 to PD4 shown in FIG. 2 are arranged lengthwise and crosswise, for example, in the shape of a "", and a return light component reflecting the address and the record information is detected. Is done.

That is, in FIG. 2, the light receiving signal A1 is detected by the light receiving element PD1 of the light detecting means 7, the light receiving signal B1 is detected by the light receiving element PD2,
The light receiving signal C1 is detected by D3 and the light receiving element PD4
As a result, the light receiving signal D1 is detected. Of the spot diameter of the perfectly circular return light L 'shown in FIG. 1, return light of a flat elliptical portion excluding the upper and lower portions (crescent portion) is detected.

Two light receiving elements PD5 and PD8 are arranged side by side above the light receiving elements PD1 to PD4, and a return light component reflecting interference information based on the preformat address on the outer peripheral side adjacent to the preformat address is detected. Is done. For example, the light receiving signal A is generated by the light receiving element PD5.
2 is detected, and the light receiving signal D2 is detected by the light receiving element PD8. Among the spot diameters of the perfectly circular return light L ′ shown in FIG. 1, return light of a crescent-shaped portion on the outer peripheral side is detected.

Further, two light receiving elements PD6 and PD7 are arranged side by side below the light receiving elements PD1 to PD4, and a return light component reflecting interference information by an inner preformat address adjacent to the preformat address is generated. Is detected. For example, the light receiving signal B is generated by the light receiving element PD6.
2 is detected, and the light receiving signal C2 is detected by the light receiving element PD7. Among the spot diameters of the perfectly circular return light L ′ shown in FIG. 1, the return light of the crescent-shaped portion on the inner peripheral side is detected.

In this example, a signal generating means 9 is connected to the light detecting means (hereinafter also referred to as an eight-division light detector) 9, and various signals are generated based on the outputs of the eight light receiving elements PD1 to PD8. . For example, the signal generating means 9 includes eleven adders 301 to 310, 321 constituting a matrix amplifier or the like.
And three differential amplifiers 322 to 324. One terminal of each of the adders 301 and 303 is connected to the output of the light receiving element PD1, and the light receiving signal A1 is input. The output of the light receiving element PD5 is connected to the other + of the adder 301.
The terminals are connected, and a light receiving signal A2 is input.

Similarly, the + terminal of one of the adders 304 and 306 is connected to the output of the light receiving element PD2, and the light receiving signal B1 is input. The other + terminal of the adder 306 is connected to the output of the light receiving element PD6, and the light receiving signal B2 is input. Further, an adder 3 is added to the output of the light receiving element PD3.
The other + terminal of 04 and one + terminal of adder 305 are connected, and light receiving signal C1 is input. Light receiving element PD7
Is connected to the other + terminal of the adder 305, and the light receiving signal C2 is input. Further, the other + terminal of the adder 303 and one + terminal of the adder 302 are connected to the output of the light receiving element PD4, and the light receiving signal D1 is input. The other + terminal of the adder 302 is connected to the output of the light receiving element PD8, and the light receiving signal D2 is input.

Further, the output of the adder 301 is
7, 310 are connected to one another, and the addition signal A1 +
A2 is input. The output of the adder 302 is
8 and the other + terminal of the adder 310 are connected, and an addition signal A1 + A2 is input. Adder 30
The output of 3 is connected to one + terminal of the adder 321 and the + terminal of the differential amplifier 322, and receives the addition signal A1 + D1. The output of the adder 304 is connected to the other + terminal of the adder 321 and the − terminal of the differential amplifier 322, and receives the addition signal B1 + C1. The adder 321 operates to output the information read signal SRF = A1 + C1 + C1 + D1, and the differential amplifier 322 outputs the wobble signal SWB = (A
1 + D1)-(B1 + C1).

The output of the adder 305 is
7, the other + terminal of the adder 309 is connected, and the addition signal C1 + C2 is input. Adder 30
6 and the other + terminal of the adder 308 and the adder 3
09 is connected to the other + terminal, and an addition signal B1 + B2 is input. The output of the adder 307 includes a differential amplifier 32
3+ terminals are connected, and the addition signal A1 + A2 + C1 + C
2 is input. The minus terminal of the differential amplifier 323 is connected to the output of the adder 308, and the addition signal B1 + B2 + D1
+ D2 is input.

The differential amplifier 323 calculates the focus error signal SFE = (A1 + A2 + C1 + C2)-(B1 + C1 + D
1 + D2). The minus terminal of the differential amplifier 324 is connected to the output of the adder 309, and the addition signal B1 + B2 + C1 + C2 is input. Adder 31
0 is connected to the negative terminal of the differential amplifier 324,
Addition signal A1 + A2 + D1 + D2 is input. The differential amplifier 324 calculates the tracking error signal STE = (A1 + A
2 + D1 + D2)-(B1 + C1 + C1 + C2).

Next, an example of the operation of the optical disc recording / reproducing apparatus 100 according to the present embodiment will be described. For example, it is assumed that recorded information is read from the optical disk 10. In this case, when the optical beam L is irradiated from the optical output means 6 to the optical disk 10 based on the preformat address, the return light L 'reflecting the read information from the optical disk 10 is reflected by the light detection means 7 by the light detection means 7. The format address and the recording information are detected separately from interference information based on the preformat addresses on the inner and outer circumferences adjacent to the preformat address.

The output of the light detecting means 7 is applied to the signal generating means 9
Is input to For example, the adder 30 of the signal generating means 9
At 1,303, a light receiving signal A1 from the light receiving element PD1 is output. The light receiving signal A2 from the light receiving element PD5 is output to the adder 301, and the light receiving signal B1 from the light receiving element PD2 is output.
Is output to the adders 304 and 306. Light receiving element PD6
Is output to the adder 306, and the light reception signal C1 from the light receiving element PD3 is output to the adders 304 and 305. Light receiving signal C by light receiving element PD7
2 is output to the adder 305.

The light receiving signal D1 from the light receiving element PD4
Is output to the adder 303 and the adder 302, and the light receiving signal D2 from the light receiving element PD8 is output to the adder 302. As a result, the addition signal A1 + A2 by the adder 301
Are output to adders 307 and 310, respectively.
02 is output to the adder 308 and the adder 310. Addition signal A by adder 303
1 + D1 is output to the adder 321 and the differential amplifier 322. The addition signal B1 + C1 from the adder 304 is output to the adder 321 and the differential amplifier 322. As a result,
The adder 321 outputs an information reading signal (hereinafter also referred to as an RF signal) SRF = A1 + B1 + C1 + D1. Wobble signal SWB from differential amplifier 322 = (A1 + D1)
− (B1 + C1) is output.

Further, the addition signal C1 + by the adder 305
C2 is output to the adders 307 and 309, and the addition signal B1 + B2 from the adder 306 is output to the adders 308 and 309, respectively. The addition signal A1 + A2 + C1 + C2 from the adder 307 is output to the differential amplifier 323. Addition signal B1 + B2 + by adder 308
D1 + D2 is output to the differential amplifier 323. As a result, the focus error signal SFE =
(A1 + A2 + C1 + C2)-(B1 + B2 + D1 + D
2) is output.

The addition signal B1 + by the adder 309
B2 + C1 + C2 is output to the differential amplifier 324, and the addition signal A1 + A2 + D1 + D2 from the adder 310 is
The signal is output to the differential amplifier 324. As a result, the tracking error signal STE = (A1 + A2) from the differential amplifier 324
+ D1 + D2)-(B1 + B2 + C1 + C2) is output.

Therefore, from the read information read from the optical disk 10, the interference information by the preformat addresses on the inner and outer circumferences is removed, and only the record information of the preformat address can be taken out from the signal generating means 9. As a result, even when the recording density of the optical disc 10 is increased and the adjacent information recording layer is irradiated with the light beam L straddling, the crosstalk can be prevented without impairing the tracking error detecting function and the focus error detecting function. it can.

(2) Embodiment FIG. 3 is a conceptual diagram showing a configuration example of an optical pickup 30 mounted on an optical disk recording / reproducing apparatus 200 as an embodiment.

The optical pickup 30 shown in FIG. 3 has the laser light source 11 as an example of the light output means. As the laser emission source 11, a GaAs semiconductor laser having a wavelength of about 780 nm is used. The laser light source 11 emits a laser beam L constituting a main spot of the three-beam method. The laser emission source 11 has an optical axis, and on the optical axis, a grating (diffraction grating) 12, a beam splitter 13, and a front monitor light receiving element 14 constituting an optical system are provided. Grating 12
In the laser beam L emitted from the laser emission source 11,
Are separated into one main beam and two side beams, and are monitored by the light receiving element 14 through the beam splitter 13.

A collimator lens 15 and a mirror 16 adjacent to the collimator lens 15 are provided on the optical axis perpendicular to the optical axis of the laser emission source 11 with the beam splitter 13 as the origin and on the right side of the beam splitter 13. A concave lens 17 and a light detecting unit 70 are provided adjacent to the concave lens 17 on the left side. The laser beam L polarized at 90 ° by the beam splitter 13 is formed into a parallel light beam by the collimator lens 15 and then applied to the mirror 16. On the optical axis polarized at 90 ° by the mirror 16, a quarter-wave plate 18 and an objective lens 19 are provided adjacent thereto. The laser beam L passes through the objective lens 19 after the phase shift is compensated by the 波長 wavelength plate 18, and
Irradiate the 0 pre-groove (recording track). The quarter-wave plate 18 may be omitted. The objective lens 19 has a numerical aperture NA that indicates the performance of the lens in the same manner as a microscope.

When the laser beam L is reflected by the optical disk 10, the return light L 'passes through the objective lens 19, the quarter-wave plate 18, the mirror 17, the collimator lens 15, the beam splitter 13, and the concave lens 17, and passes through the light detecting section. 70. The light detection unit 7 for detecting the main spot described in the embodiment is applied to the light detection unit 70. Of course, differential push-pull (hereinafter simply DPP
If the method is adopted, the light detecting means 7
In addition to the two light receiving elements PD1 to PD8, two light receiving elements PD9 and PD10 for the preceding spot and two light receiving elements PD11 and PD12 for the following spot described with reference to FIG. 8 may be added.

Next, an example of the configuration of the optical disk 10 to which the optical pickup 30 is applied and an example of three-beam irradiation will be described. The optical disk 10 shown in FIG. 4A is a write-once optical disk (CD-R) or a rewritable optical disk (CD-RW), and is partially cut and enlarged. Here, a land 2 is defined between two adjacent pregrooves 1. On the optical disc 10, a pregroove 1 serving as a groove for guiding a light beam is spirally formed from an inner peripheral portion to an outer peripheral portion with a chuck hole (not shown) as a center. It is adapted to guide a laser beam L. The pre-groove 1 is defined (partitioned) by a land 2 and is slightly sinusoidal (wobbling). A dye layer serving as a recording layer is formed on the pre-groove 1, and a land or the like and a reflection layer such as gold are formed on the pre-groove 1 so as to cover the dye layer. I have. Thereby, CD-R,
The optical disk 10 such as a CD-RW is configured.

As shown in the example of irradiation of three beams in FIG. 4B, wobble is applied to both sides of the pregroove 1 which is also the slope of the land 2 shown in FIG. The wobble component is based on a control signal for forming a groove when the master of the optical disc 10 is created.
FM modulation processing has been performed. 4B is the spot diameter of the laser beam L, which is the case where the irradiation diameter becomes relatively large due to the proportional reduction of the pre-groove accompanying the increase in the recording density of the optical disk 10.

When producing a master for the optical disk 10, first, a pre-format address is baseband-modulated by a modulation method called bi-phase.
A control signal for forming a groove is created based on the bi-phase signal DBP thus obtained. By this control signal, a light beam of a predetermined intensity is vibrated on the master in the inner and outer peripheral directions, and a groove is dug while rotating the master at a predetermined linear velocity, and a pre-groove 1 and a land 2 are formed on the master. To be defined. As a result, a pre-format address (hereinafter also referred to as time axis information) is written, and a master disc on which the recommended value of the optimum recording power of the laser light and the like are encoded is created. Based on this master disc, an optical disc 10 called a blank disc is created. Is formed.

The above-mentioned time axis information comprises at least one frame of synchronization information, minute information, second information, frame information and error correction information. Hereinafter, time axis information for all frames is also referred to as ATIP (Absolute Time In Pregroove) information. The ATIP information includes, for example, both side surfaces Us of the pregroove 1 between the two lands 2a and 2b shown in FIG. 4B,
Ut, that is, writing is performed in synchronization with the side surface Us of the land 2a located on the inner peripheral side of the pre-groove 1 for recording data and the side surface Ut of the land 2b located on the outer peripheral side thereof. Therefore, the ATIP information can be read as the wobble signal SWB by detecting the wobble shape formed on the land 2b located on the outer peripheral side with the preceding side spot 3.

The preceding side spot 3 is a light beam preceding the main spot 4 which is a laser beam L for recording and reading information. The wobble shape formed on the land 2a located on the inner peripheral side is detected as the wobble signal SWB by the trailing side spot 5. The wobble signal SWB is generated so that the center frequency becomes, for example, 22.05 kHz when the disk is rotated at a standard speed (CLV) of a CD (Compact Disc). One sector of the ATIP information matches one data sector (2352 bytes) after signal recording. Therefore, at the time of information recording, data writing is performed while synchronizing the sector of the ATIP information with the data sector. For example, when a preformat address is designated, a laser beam L having a predetermined intensity is applied to the pregroove 1 to write information.

Here, an example of the relationship among the ATIP information, the biphase signal DBP, and the wobble signal SWB will be described. The ATIP information shown in FIG. 5A is bi-phase modulated, and is adjusted so that the logical levels “1” and “0” are switched at predetermined intervals and the average number of “1” and “0” becomes equal. FIG. 5B obtained by this biphase modulation.
The bi-phase signal DBP shown in (1) is then FM-modulated to be a wobble signal (control signal for forming a groove) SWB. That is, when the logic level of the biphase signal DBP is "1", the frequency is 23.05 kHz, and when the logic level is "0", the frequency is 21.05 kHz.
and the center frequency is 22.05k as described above.
The wobble signal SWB shown in FIG. 5C, in which the carrier signal is FM-modulated so as to become Hz.

Here, an example of a frame structure of ATIP information forming a preformat address will be described. The first four bits of the ATIP information shown in FIG. 6 are synchronization information, and are a synchronization signal SYNC. The next 8 bits are 2Dight
This is minute information indicated by BCD. The next next 8 bits are second information indicated by 2Dight BCD. Next 8
The bit is frame information indicated by 2Dight BCD. The last 14 bits are cyclic code CRC (Cyclic Red).
undacy code), and the preformat address of one frame is composed of 42 bits. The information such as the recommended value of the optimum recording power of the laser beam is multiplexed so as to be included in the time axis information at a certain ratio.

Next, an example of the configuration of an optical disk recording / reproducing apparatus 200 equipped with the optical pickup 30 will be described. The optical disc recording / reproducing apparatus 200 shown in FIG. The optical disk 10 is rotated at a predetermined speed by a spindle motor unit 22. The spindle motor unit 22 is driven by a spindle drive signal SSD from a spindle motor drive unit 23 to be described later so that the rotation speed of the optical disc 10 becomes a predetermined speed.

The optical disk 10 is irradiated with a laser beam L whose light amount is controlled from the optical pickup 30 of the optical disk recording / reproducing apparatus 200. Optical disk 1
The laser beam L reflected by the optical pickup 3
0 is detected by the light detector 70 (see FIG. 3).

As the light detecting section 70, an eight-division light detector 7 for detecting the return light L 'of the main spot 4 as described with reference to FIG. 2 is used. The function is as described in the embodiment. When the DPP method is employed, an eight-segment photodetector 311 shown in FIG. 8, a two-segment photodetector 312 for detecting the return light of the preceding side spot 3, and a return light L 'of the succeeding side spot 5 are detected. Split photodetector 313
Is preferably used. A voltage signal generated by the current-voltage conversion in each of the split photodetectors 311 to 313 is supplied to the RF amplifier unit 32.

In the RF amplifier section 32, the tracking error signal STE is generated by using a differential push-pull method capable of obtaining a tracking error signal containing almost no DC fluctuation.

The output of the eight-segment photodetector 311 shown in FIG. For example, the light receiving signal A1 from the light receiving element PD1 is output to the adders 301 and 303 of the RF amplifier unit 32. The light receiving signal A2 from the light receiving element PD5 is output to the adder 301, and the light receiving signal B1 from the light receiving element PD2 is output to the adders 304 and 306. The light receiving signal B2 from the light receiving element PD6 is added to the adder 306.
And the light receiving signal C1 from the light receiving element PD3 is output to the adder 304 and the adder 305. Light receiving element PD
7 is output to the adder 305.

The light receiving signal D1 from the light receiving element PD4
Is output to the adder 303 and the adder 302, and the light receiving signal D2 from the light receiving element PD8 is output to the adder 302. As a result, the addition signal A1 + A2 by the adder 301
Are output to adders 307 and 310, respectively.
02 is output to the adder 308 and the adder 310. Addition signal A by adder 303
1 + D1 is output to the adder 321. The addition signal B1 + C1 from the adder 304 is output to the adder 321.
As a result, the adder 321 outputs an RF signal (information read signal).
SRF = A1 + B1 + C1 + D1 is output.

Further, the addition signal C1 +
C2 is output to the adders 307 and 309, and the addition signal B1 + B2 from the adder 306 is output to the adders 308 and 309, respectively. The addition signal A1 + A2 + C1 + C2 from the adder 307 is output to the differential amplifier 323. Addition signal B1 + B2 + by adder 308
D1 + D2 is output to the differential amplifier 323. As a result, the focus error signal SFE =
(A1 + A2 + C1 + C2)-(B1 + B2 + D1 + D
2) is output.

The addition signal B1 + by the adder 309
B2 + C1 + C2 is output to the differential amplifier 324, and the addition signal A1 + A2 + D1 + D2 from the adder 310 is
The signal is output to the differential amplifier 324. As a result, these difference signals (A1 + A2 + D1 + D2) are output from the differential amplifier 324.
− (B1 + B2 + C1 + C2) is output.

Return light (reflected light) of preceding side spot 3
, The light receiving element PD9
, The light receiving signal E from the light receiving element PD10 and the light receiving signal F from the light receiving element PD10 are supplied to the differential amplifier 325 of the RF amplifier unit 32. In the differential amplifier 325, the difference between the received light signal E and the received light signal F is amplified, and the difference signal is supplied to the differential amplifier 331 via the amplifier 329 having a predetermined gain g1.

The light receiving element PD11 of the two-segment photodetector 313
Light receiving signal G from light receiving element H and light receiving signal H from light receiving element PD12
Is supplied to the differential amplifier 326 of the RF amplifier unit 32. The differential amplifier 326 amplifies the difference between the received light signal G and the received light signal H, and the difference signal is amplified by an amplifier 330 having a predetermined gain g2 and an amplifier 329 having a predetermined gain g1.
Is supplied to the differential amplifier 331 via As a result, the tracking error signal STE = (A
1 + A2 + D1 + D2)-(B1 + B2 + C1 + C2)
−g1 {(FE) + g2 (GH)} is output.
The wobble signal SWB is supplied from the differential amplifier 328 to SWB = (A1 + D1)-(B) in the same manner as in the embodiment shown in FIG.
1 + C1) is output.

As described above, the RF signal SRF, tracking error signal STE, and focus error signal SFE generated by the RF amplifier unit 32 are generated by the clock generation / signal shown in FIG.
It is supplied to the servo control unit 33. The wobble signal SWB is supplied to the ATIP decoder 34 shown in FIG.

Returning to FIG. 7, the clock generation / servo control unit 33 sets the focal position of the laser beam L to the position of the recording layer of the optical disk 10 based on the focus error signal SFE supplied from the RF amplifier unit 32. A focus control signal SFC for controlling the objective lens 19 (see FIG. 3) of the optical pickup 30 is generated by the driver 3.
5 is supplied. In the servo control unit 33, RF
The tracking error signal S supplied from the amplifier 32
A tracking control signal S for controlling the objective lens 19 of the optical pickup 30 so that the irradiation position of the laser beam L is located at the center of a desired track based on TE.
TC is generated and supplied to the driver 35.

In the driver 35, a focus drive signal SFD is generated based on the focus control signal SFC, and a tracking drive signal STD is generated based on the tracking control signal STC. The generated focus drive signal SFD and tracking drive signal STD are supplied to an actuator (not shown) of the optical pickup 30, whereby the position of the objective lens 19 is controlled.
The laser beam L is controlled so as to be focused at the center position of the desired track.

The clock generation / servo control unit 33 converts the RF signal SRF supplied from the RF amplifier unit 32 into a digital signal by performing asymmetry correction and binarization, and converts the digital signal into a read data signal DRF. The data is supplied to the data processing unit 40. Further, a clock signal CKRF synchronized with the above-described digital signal is generated, and the generated clock signal CKRF is supplied to the data processing unit 40.

Further, the clock generation / servo control unit 33
Then, a thread control signal SSC for moving the optical pickup 30 in the radial direction of the optical disk 10 is generated and supplied to the thread unit 36. This is to prevent the irradiation position of the laser beam L from exceeding the tracking control range. The sled section 36 drives the sled motor based on the sled control signal SSC to move the optical pickup 30 in the radial direction of the optical disc 10.

Here, a configuration example of the ATIP decoder 34 to which the wobble signal SWB is supplied will be described. In this example, the ATIP decoder 34 shown in FIG. 9 includes a bandpass filter 341, a waveform shaping unit 342, a detecting unit 343, and an address decoding unit 344. The wobble signal SWB1 is supplied to the bandpass filter 341 of the ATIP decoder 34. The wobble signal SWB band-limited so that the wobble component and the wobble component by the following side spot 5 are extracted by the band filter 341 is supplied to the waveform shaping unit 342.

In the waveform shaping section 342, the wobble signal S
A clock signal CKWB synchronized with the carrier component is generated from WB, and the wobble signal SWB is binarized. The generated clock signal CKWB and wobble information DWB obtained by binarizing the preceding wobble component are detected by the detector 343.
Supplied to

In the detection section 343, the wobble information DWB is demodulated using the clock signal CKWB to generate a bi-phase signal DBP, and also generates a clock signal CKBP synchronized with the bi-phase signal DBP. The generated bi-phase signal DBP and clock signal CKBP are supplied to the address decoding unit 344.

The address decoder 344 demodulates the bi-phase signal DBP using the clock signal CKBP to generate a preformat address DAD. The address decoding unit 344 detects a synchronization pattern of the preformat address DAD and generates an ATIP synchronization detection signal FSY. This pre-format address DAD is supplied to the control unit 50 and the ATI
The P synchronization detection signal FSY is supplied to the spindle motor drive unit 23.

Returning to FIG. 7, in the data processing unit 40, the read data signal DRF is EFM-demodulated, and
Deinterleave processing and CIRC (Cross
Error correction processing by Interleave Reed-Solomon Code) is performed. Furthermore, a sync pattern is detected, and descrambling processing, error correction processing by ECC (Error Correcting Code), and the like are also performed. Here, the data signal subjected to the error correction processing is stored in a RAM 42 as a buffer memory, and then supplied as a reproduced data signal RD to an external computer device or the like via an interface 43.

The data processing section 40 detects the frame synchronization signal FSZ from the data signal after the EFM demodulation, and supplies the frame synchronization signal FSZ to the spindle motor driving section 23. This spindle motor drive unit 2
3, the ATIP synchronization detection signal FSY from the ATIP decoder 34 is used when recording a signal on the optical disk 10, and the frame synchronization signal FSZ from the data processing unit 40 or the ATIP synchronization Synchronization detection signal FS
Y is used to generate a spindle drive signal SSD for rotating the optical disc 10 at a desired speed. By supplying the spindle drive signal SSD generated by the spindle motor drive unit 23 to the spindle motor unit 22, the optical disc 10 is rotated at a desired speed.

Further, when the recording data signal WD is supplied from an external computer device via the interface 43, the data processing section 40 temporarily stores the recording data signal WD in the RAM 42, and simultaneously stores the recording data signal WD in the RAM 42. The signal WD is read and encoded into a predetermined sector format, and an error correction ECC addition process is performed. Further, in the data processing unit 40, C
An IRC encoding process, EFM modulation, and the like are also performed to generate a write signal DW. The generated write signal DW is supplied to the write compensator 37.

In the write compensating section 37, the laser drive signal L based on the write signal DW supplied from the data processing section 40 is used.
An AD is generated, and a laser drive signal LAD is supplied to a laser emission source (laser diode) 11 of the optical pickup 30. Here, in the write compensating section 37, the optical disc 1 is controlled based on a power compensation signal PC from the control section 50 described later.
0 recording layer characteristics and the spot shape of the laser beam L,
The signal level of the laser drive signal LAD is corrected according to the recording linear velocity, etc.
The power of the laser beam L output from is optimized to perform a signal recording operation.

A ROM 51 is connected to the control unit 50, and controls the operation of the optical disk recording / reproducing apparatus 200 based on an operation control program stored in the ROM 51. For example, the control unit 50 controls the subcode signal DSQ generated by the data processing unit 40 or the ATIP decoder 34.
The reproduction position and the recording position on the optical disc 10 are determined based on the preformat address DAD from the CPU 10 and the control signal CTA is supplied to the clock generation / servo control unit 33 and the control signal CTB and the like to the data processing unit 40, so that the data Recording / reproducing operation.

The control unit 50 generates a power compensation signal PC based on the setting information of the recording laser power indicated by the preformat address DAD, and
To supply. A control signal CTC is supplied from the control unit 50 to the RF amplifier unit 32 so that the RF amplifier unit 32 controls on / off of the laser emission source 11 of the optical pickup 30 and reduces laser noise and disturbance to the RF signal. Processing for superimposing a high frequency wave on the laser beam L is also performed.

Next, an operation example of the optical disk recording / reproducing apparatus 200 will be described. In this example, it is assumed that the optical disk 10 shown in FIG. 4A is mounted on the optical disk recording / reproducing apparatus 200 to record and reproduce signals. Also,
It is assumed that recorded information is read from the optical disk 10 on which information is recorded based on the preformat address.

At the time of recording information on the optical disk 10 In this case, the wobble shape is read using the main spot 4 shown in FIG. 4B, and the wobble signal SWB is reproduced. Based on the wobble signal SWB, the optical disk 10 is rotated at a predetermined speed, and the preformat address of the track where the main spot 4 is located is determined. Based on the address determination result, the irradiation position of the laser beam L is controlled so that the main spot 4 is at a desired track position, and when the main spot 4 is at a desired track position, data writing is started. You. During the period in which the data writing is not performed, the reading of the time axis information based on the wobble signal SWB is performed in the main spot 4.

At the time of reproducing information from the optical disk 10 In this case, the optical disk 10 is irradiated with the laser beam L based on the preformat address, and the return light L ′ reflected from the optical disk 10 is Return light component (A1 + D1, B1) reflecting the preformat address and recording information
+ C1) and a return light component (A2 + D2, B2 + C2) including an interference signal due to the inner and outer preformat addresses adjacent to the preformat address.

Accordingly, the rotation of the optical disk 10 is controlled based on the RF signal SRF from the optical pickup 30. Further, since the reproduction position can be determined based on the subcode signal DSQ generated based on the RF signal SRF, desired data can be read using the reproduction position information.

As described above, according to the optical disc recording / reproducing apparatus 200 according to the present embodiment, the interference information by the preformat addresses on the inner and outer circumferences is removed from the read information read from the optical disc 10, and the RF of the preformat address is removed. Since only the signal (recording information) SRF can be taken out, even if the recording density of the optical disc 10 is increased and the laser beam L is straddled to the adjacent information recording layer, the tracking error detection function and the focus detection function Crosstalk can be prevented without compromising the performance.

By the way, even if the laser wavelength is shortened or the numerical aperture (NA) of the objective lens 19 is increased due to the demand for high recording density of the optical disc 10, there is a limit in reducing the beam spot diameter. Thus, crosstalk from adjacent tracks can be prevented, and the information reading performance of the optical disc recording / reproducing apparatus 200 can be improved.

In the above-described embodiment, the preformat address is read using only the main spot 4 to generate the tracking error signal STE by the differential push-pull method. May be read out using the side spot 3 for generating the tracking error signal STE.

[0087]

As described above, according to the optical disk recording / reproducing apparatus according to the present invention, when reading recorded information from an optical disk on which information is recorded based on a pre-formed address, the read information from the optical disk is read. A light detecting means is provided for detecting the return light including the address and recording information and the interference information based on the inner and outer peripheral addresses adjacent to the address.

With this configuration, it is possible to extract only the recorded information of the address from which the interference information by the inner and outer addresses has been removed from the read information read from the optical disk. Therefore, even when the recording density of the optical disk is increased and the adjacent information recording layer is irradiated with the light beam straddling, crosstalk can be prevented without impairing the tracking error detecting function and the focus detecting function.

According to the information reading method of the present invention, when reading out recorded information from an optical disk on which information is recorded based on a pre-formed address, the optical disk is irradiated with a light beam and reflected from the optical disk. The incoming return light is detected separately in a return light component reflecting the address and the record information and a return light component reflecting interference information by the inner and outer addresses adjacent to the address.

With this configuration, it is possible to extract only the record information of the address from which the interference information by the inner and outer addresses has been removed from the read information read from the optical disk. The present invention relates to a write-once optical disc (CD-
R) or rewritable optical disk (CD-RW)
It is very suitable for application to writable optical disks such as.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration example of an optical disc recording / reproducing apparatus 100 as an embodiment of the present invention.

FIG. 2 shows a light detecting means 7 of the optical disk recording / reproducing apparatus 100.
FIG. 2 is a block diagram illustrating a configuration example of a signal generation unit 9.

FIG. 3 is an optical disc recording / reproducing apparatus 200 as an embodiment.
FIG. 2 is a conceptual diagram showing a configuration example of an optical pickup 30 mounted on the optical pickup.

FIGS. 4A and 4B are diagrams showing a configuration example of an optical disc 10 to which the optical pickup 30 is applied and an irradiation example of three beams.

5A to 5C are ATIP information and a bi-phase signal DBP.
FIG. 7 is a waveform chart showing an example of the relationship between the wobbled signal and a wobble signal SWB.

FIG. 6 is a data format showing an example of a frame structure of ATIP information forming a preformat address.

FIG. 7 is a block diagram showing a configuration example of an optical disk recording / reproducing apparatus 200 as an embodiment equipped with an optical pickup 30.

8 is a block diagram showing a configuration example of an eight-segment photodetector 311, two-segment photodetectors 312, 313, and an RF amplifier unit 32 applied to the optical pickup 30. FIG.

9 is a block diagram illustrating a configuration example of an ATIP decoder 34. FIG.

FIG. 10A is a configuration example of an optical disc 10 according to a conventional example,
7A and 7B are diagrams showing examples of light beam irradiation.

FIG. 11 is a diagram for explaining a method of reproducing a wobble signal in a photodetector 71 according to a conventional example.

[Explanation of symbols]

6 ... light output means, 7 ... light detection means, 9 ... signal generation means, 10 ... optical disc, 22 ... spindle motor section, 23 ... spindle motor drive section, 3
0 ... optical pickup, 70, 71 ... light detection unit (light detection means), 32 ... RF amplifier unit (signal generation means), 33 ... clock generation / servo control unit, 34 ...
..ATIP decoder, 37... Write compensator, 40.
..Data processing section, 43... Interface, 50.
..Control units, 100, 200: optical disk recording / reproducing devices, 311-313, 711-713, divided light detectors, 301-310, 321: adders, 322
326, 331... Differential amplifiers, 329, 330.
.Amplifier, 341, band-pass filter, 342, waveform shaping section, 343, detection section, 344, address decoding section, PD1 to PD12, light receiving element

Claims (5)

[Claims] 1. An optical disk recording / reproducing apparatus which records or reproduces recorded information on or from an optical disk on which information is to be recorded based on the address, wherein the optical disk is irradiated with a light beam. Light output means, and return light including read information from the optical disc,
An optical disc recording / reproducing apparatus, comprising: a light detecting unit for detecting the address and the recording information separately from the interference information based on the inner and outer peripheral addresses adjacent to the address. 2. The light detecting means has at least eight light receiving elements, and the light receiving elements are arranged in a matrix of 2 rows × 4 columns based on a light receiving axis. An optical disk recording / reproducing apparatus according to claim 1. 3. The eight light receiving elements of the light detecting means are arranged vertically and horizontally at the center of the light receiving axis, and detect a return light component reflecting the preformat address and the recorded information.
Light receiving elements, and two light receiving elements on each of two opposing sides of the four light receiving elements.
3. The device according to claim 2, further comprising: another four light receiving elements that are arranged side by side and detect return light components including interference information based on inner and outer peripheral preformat addresses adjacent to the preformat address. An optical disk recording / reproducing apparatus according to claim 1. 4. A signal generating means for generating various signals based on an output of the light detecting means, the signal generating means comprising: four light receiving elements arranged vertically and horizontally at the center of a light receiving axis of the light detecting means. An RF signal and a wobble signal representing the address are created based on an output of an element, and a tracking error signal or a focus error signal is created based on outputs of eight light receiving elements of the photodetector. Item 3. An optical disk recording / reproducing apparatus according to item 2. 5. A method for reading recorded information from an optical disc on which information is recorded based on the address, wherein the optical disc is irradiated with a light beam and reflected from the optical disc. An information reading method, wherein a return light component reflecting the address and the record information and a return light component reflecting interference information by an inner and outer address adjacent to the address are detected separately for the return light. .