JPH0386935A - Method for recording and reading for optical disk - Google Patents

Abstract

PURPOSE:To record/reproduce continuous signals as they are and to increase a data area where information is recorded besides by making a light spot access a prescribed address position and recording (or reading) the information while the light spot is made to follow up a pregroup (or a land) based on an inversion control signal thereafter. CONSTITUTION:Address information which is read by an address read circuit 8 is fetched and the beam spot S is made to access the specified address. Thereafter, a kick pulse is generated by controlling the driving of a kick pulse generation circuit 17 and the beam spot S is moved to the adjacent pregroup 21 on a side which is decided by the polarity of the kick pulse from the land 22. Simultaneously, the polarity of a tracking error signal is inverted by controlling the switching of a signal switching circuit 12. Continuously, a tracking servo is closed by executing the leading-in of the tracking servo. Thus, the continuous signals such as the format signal of a compact disk (CD) are recorded as they are and read. Besides, the data area is increased by as much as the address area which does not exist.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a recording/reading method for an optical disc, and in particular to a DR
Optical disks such as AW (write once) and EDRAW (erase/rewrite) (including magneto-optical and phase change disks)
related to a record reading method.

BACKGROUND ART As shown in FIG. 3, this type of optical disc has a pregroove 21 that guides a light spot for recording/reproducing information.
In the land 22 between the pregrooves 21, a preformat pattern (hereinafter referred to as an address area) such as address information is recorded in advance as fixed window information.

In such an optical disc, information is recorded in a data area that exists with a gap in relation to the address area, so there is no problem when using the disc as a data file, for example.・When used as an editing machine for CD format signals, the format of the CD format signal must be changed and recorded.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a recording/reading method for an optical disc that can record/reproduce continuous signals such as CD format signals as they are, and can increase the data area in which information can be recorded.

A recording/reading method for an optical disc according to the present invention is a method for recording/reproducing information on an optical disc that has a pregroove for guiding a light spot and address information is recorded in advance on lands (or pregrooves) between the pregrooves. , generates control signals of polarity and level according to the direction and amount of deviation of the light spot with respect to the land (or pregroove), and generates address information while making the light spot follow the land (or pregroove) based on this control signal. The optical spot is accessed to a predetermined address position by reading the information, and then the polarity of the control signal is reversed, and the optical spot is made to follow the pregroove (or land) based on an inverted control signal obtained by recording information. (or reading).

Example Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

In FIG. 1, a beam spot S obtained by converging a laser beam is transmitted from an optical head (not shown) to a land 22 (or pregroove 2) of an optical disk.
1) is irradiated.

The light beam reflected from the disk surface by the beam spot S is incident on a photoelectric conversion element 1.degree.2 built into the optical head, and is converted into an electric signal. In addition to the optical system including the objective lens, the optical head includes a focus actuator that controls the position of the objective lens in the optical axis direction with respect to the disk surface, and a focus actuator that controls the position of the objective lens in the optical axis direction with respect to the disk surface, and a focus actuator that controls the position of the beam spot S in the disk radial direction with respect to the land 22 (or pregroove 21). It has a built-in tracking actuator that controls the position of the This optical head is mounted on a carriage (not shown) that is movable in the radial direction of the disk.

The photoelectric conversion element 1 includes, for example, four light-receiving elements that are arranged so as to divide the light-receiving surface into four and are independent of each other. Then, the output sum of the elements facing each other with respect to the center of the light receiving surface is supplied to the adder 4, and a sum signal of both output sums, that is, a sum signal of each light receiving element is derived, and this sum signal becomes the read RF multiplied signal. . Note that the focus error signal can be derived by obtaining the difference between the above respective output sums. The read RF multiplied signal is supplied to the demodulation circuit 6 via the RF amplifier 5. This demodulated output is subjected to predetermined signal processing in a signal processing circuit 7 to become a reproduced output, and is also supplied to an address reading circuit 8 to read address information. Address reading circuit 8
The address information read in is supplied to the controller 9.

On the other hand, the output of the pair of photoelectric conversion elements 2 is output from the amplifier 10.11.
After being amplified, the signal is supplied to the differential amplifier 13 via the signal switching circuit 12 to derive a re-output difference signal, and this difference signal becomes a tracking error signal. Signal switching circuit 12
switches to supply the output of the amplifier 10 to the non-inverting input terminal or inverting input terminal of the differential amplifier 13, and the output of the amplifier 11 to the inverting input terminal or non-inverting input terminal of the differential amplifier 13, and by this switching, the tracking Inverts the polarity of the error signal. Switching control of the signal switching circuit 12 is performed by a controller 9. The difference signal of the differential amplifier 13, that is, the tracking error signal, is sent to an equalizer (EQ
) After the frequency and phase characteristics are compensated in the circuit 14, the signal passes through the loop switch 15 and the drive circuit 16 and becomes a drive signal for a tracking actuator (not shown).

As described above, a tracking servo loop is formed, and when the loop switch 15 is on (closed), it is in a loop closed state, and in this loop closed state, the tracking actuator is activated based on the polarity and level of the tracking error signal. By driving
This allows the beam spot S to accurately follow the land or pregroove.

The controller 9 is composed of, for example, a microcomputer, and under the control of the processor controls the switching of the signal switching circuit 12 and turns on/off the loop switch 15.
It performs off control, drive control of the kick pulse generation circuit 17, etc. The kick pulse generation circuit 17 generates a kick pulse having a pulse width and peak value that moves the beam spot S by one-half (p/2) of the land pitch p in the disk radial direction. This kick pulse is the drive circuit 1
6 to the tracking actuator, which causes the beam spot S to move from the land to the pregroove.
Or it will be displaced from the pregroove to the land.

Although the configuration of the recording system is omitted in Figure 1, the recording system is of a well-known configuration using an optical modulator that turns on and off a laser beam depending on the information to be recorded. can be used.

Next, the processing procedure of the record reading method according to the present invention executed by the processor of the controller 9 will be explained according to the flowchart of FIG. In this example, a case will be described in which the present invention is applied to an optical disc in which address information is recorded on a land, but it is of course applicable to an optical disc in which address information is recorded in a pregroove.

First, in step S1, the processor searches for the land in which the specified address is recorded using a well-known search method.
), then the tracking servo is pulled in at that land and the tracking servo is closed (
Step S2). As a result, the beam spot S follows the land. Next, address reading circuit 8
The address information read in step S3 is taken in (step S3
), it is determined whether the read address is a designated address or not (step S4), and by repeating this operation, the designated address of the beam spot S is accessed.

After accessing the specified address, the tracking servo loop is opened (step S5), and then the kick pulse generation circuit 17 is driven and controlled to generate a kick pulse, thereby moving the beam spot S from the land to the adjacent side determined by the polarity of the kick pulse. the signal switching circuit 12 at the same time (step S6).
The polarity of the tracking error signal is inverted by switching control (step S7). Subsequently, the tracking servo is pulled in and the tracking servo is closed (step S8). As a result, the beam spot S follows the pregroove. In this state, the mode shifts to information recording (or reading) mode.

With this processing procedure, in an optical disc in which address information is recorded on the land 22 (or pregroove 21), information is recorded (or read) on the pregroove 21 (or land 22), as shown in FIG. It will be done against. In this way, by recording information in the pregroove 21 (or land 22) where address information is not recorded, there is no interruption in the recorded signal due to the presence of the address area, and continuous signals such as CD format signals can be formatted. The data can be recorded as is without changing it, and since there is no address area in the pregroove 21 (or land 22) to be recorded, the data area can be increased accordingly.

When recording information, be sure to write the following at the end of a series of information.
When recording signals compliant with CD format,
Information rAAJ is recorded as the track number of the end area, and when recording as a general data file, a file called rEOF (end off file) is provided. Therefore, when reading recorded information, track No., rAAJ or rE
By detecting OFJ, it is possible to detect the end of a series of information, so at the time of detection, and when recording information, the beam spot S is returned to the land 22 (or pregroove 21) at the end of the recording. The address information recorded next in the axial direction is read. For example, if there is another designated address, the next designated address is searched based on the current address read by repeating the processing procedure in Figure 4, and then After reading the designated address, move the beam spot S to the pregroove 21 (or land 2).
2), the reading or recording operation is repeated again.

When recording information, pregroove and This means that crosstalk with land can be suppressed.

As described in detail, the optical disc recording/reading method according to the present invention can be applied to an optical disc that has a pregroove and address information is recorded in advance on the lands (or pregrooves) between the pregrooves. information is recorded in the pregroove (or land) where address information is not recorded, and this information is read.
Continuous signals such as format signals can be recorded and read as is without changing the format.
Moreover, the data area can be increased by the absence of an address area.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of the configuration of a disk device according to the present invention, FIG. 2 is an enlarged plan view showing the recording state of an optical disk recorded by the recording method of the present invention, and FIG. 3 is a conventional recording method. FIG. 4 is an enlarged plan view showing the recording state of the optical disc recorded by the above method, and FIG. 4 is a flowchart showing the processing procedure of the optical disc recording/reading method according to the present invention. Explanation of symbols of main parts 1.2...Photoelectric conversion element 8...Address reading circuit 9...Controller 2...Signal switching circuit 5... ...Loop switch 7...Kick pulse generation circuit

Claims (2)

[Claims] (1) A recording/reading method for an optical disc having a pre-groove for guiding a light spot and address information being recorded in advance on lands (or pre-grooves) between the pre-grooves, the land (or pre-groove) generates a control signal of polarity and level according to the direction and amount of deflection of the light spot with respect to the land, and moves the light spot to the land (
or a pre-groove), the light spot is accessed to a predetermined address position by reading the address information, and then the light spot is controlled based on an inverted control signal obtained by reversing the polarity of the control signal. A method for recording and reading an optical disc, characterized in that information is recorded (or read) while following the pregroove (or land). (2) After recording (or reading) information on the pregroove (or land), the light spot is moved to the land (or pregroove) based on a control signal obtained by reversing the polarity of the control signal. 2. The optical disc recording/reading method according to claim 1, wherein the address information recorded next in the time axis direction is read while following the address information.