JPH05274694A - Disk device - Google Patents

Abstract

PURPOSE:To accurately position an optical head in a characteristic data area by using the detector for detecting an innermost circumferential position of the optical head on a disk without using an exclusive detector. CONSTITUTION:This device is constituted so that by using the detector 36 detecting a fact that the moving position of the optical head 3 is placed on the innermost circumference of the disk 1, and further, by correcting the output of the detector 36 so as to detect it in a stable state, a fact that a laser beam from the optical head 3 irradiates the central part of the radial position of a characteristic data recording area 1b is detected and the movement of the optical head 3 is stopped by the detected result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk device for recording or reproducing information on, for example, an optical disk.

[0002]

2. Description of the Related Art As is well known, various disk devices have been developed for recording information on an optical disk or reading information recorded on an optical disk by laser light output from a semiconductor laser in an optical head. There is.

A characteristic data recording area is provided outside the recording area (inner peripheral portion) on the optical disc, and the mode information, which is commonly assigned to the optical discs of all manufacturers as characteristic data, is provided in the area in the form of a bar code. What is recorded is considered.

In this characteristic data recording area, reading,
In order to determine the writing mode, information such as the reflectance, the laser power at the time of writing and reading, the number of sectors in one round, etc. is recorded. Thus, the information in the characteristic data recording area is read to maintain the compatibility between the optical disc and the device.

Such a characteristic data recording area is read by using a scale sensor and fixing the optical head at that position. However, recently, since a position detecting method of the optical head which does not use the scale sensor is adopted, the characteristic is recorded. It was necessary to prepare a dedicated detector for detecting the data recording area.

Therefore, instead of using a dedicated detector for positioning the characteristic data recording area, a detector for detecting the innermost circumferential position of the optical head with respect to the disk is used.
A method of performing positioning with respect to the characteristic data recording area has been proposed. However, with such a detector,
However, there is a drawback in that there is a great deal of variation with respect to the external environment such as dust adhesion and temperature change, and reliability is lacking.

[0007]

As described above, the detector for detecting the innermost circumferential position of the optical head on the disc is used without using a detector dedicated to the positioning of the characteristic data recording area of the optical disc. The detector that positions the characteristic data recording area has a problem in that it has large variations with respect to the external environment such as dust adhesion and temperature change, and lacks reliability.

Therefore, according to the present invention, a detector for detecting the innermost circumferential position of the optical head with respect to the disk is used for positioning the highly reliable characteristic data recording area without using a dedicated detector. It is an object of the present invention to provide a disk device that can be used.

[0009]

According to the present invention, there is provided a light collecting means for collecting light on a disk having a characteristic data recording area in which characteristic data as mode information is recorded.
Moving means for moving the light collecting means in the radial direction of the disk, and whether the position of the light collecting means is positioned at the innermost or outermost start position of the disk according to the movement of the moving means. Light detection means for detecting whether or not there is light, correction means for correcting the output value of the light detection signal to a constant value by the light detection means when the light collection means is not in the characteristic data recording area, and the correction means Determining means for determining whether the light collecting position by the light collecting means is the characteristic data recording area on the disc using the light detection signal,
When the characteristic data recording area is accessed, the focusing means is moved in the radial direction of the disc by the moving means, and when the judgment result from the judging means is supplied, the movement by the moving means is stopped. Therefore, the light from the light collecting means is condensed on the characteristic data recording area.

[0010]

According to the present invention, the light is condensed by the light collecting means on the disk having the characteristic data recording area in which the characteristic data as the mode information is recorded, and the light collecting means is moved in the radial direction of the disk. In accordance with the above, the light detecting means detects whether or not the position of the light collecting means is located at the start position of the innermost circumference or the outermost circumference of the disk. When it is not in the area, the output value of the light detection signal is corrected to a constant value by the correction means, and the light collection position by the light collection means becomes the characteristic data recording area on the disc using the corrected light detection signal. When the characteristic data recording area is accessed, the focusing means is moved in the radial direction of the disc,
When the judgment result from the judgment means is supplied, the movement by the movement means is stopped so that the light by the condensing means is condensed on the characteristic data recording area.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows a disk device.
That is, a groove (recording track) is spirally formed on the surface of a disc (recording medium) 1 including an optical disc, and the disc 1 is rotated at a constant speed by a motor 2, for example. This motor 2
Are controlled by the motor control circuit 18.

In the disk 1, a metal coating layer of tellurium or bismuth, that is, a recording film is coated in a donut shape on the surface of a circular substrate made of glass or plastics, and the center of the metal coating layer is formed. A notch, that is, a reference position mark is provided near the portion.

On the disk 1, as shown in FIGS. 1A and 3, a data recording area 1a in which guide grooves (recording tracks) are formed, and an inner circumference of the data recording area 1a are formed. And a characteristic data recording area 1b having no guide groove provided on the side.

In the characteristic data recording area 1b, the same characteristic data is recorded in advance in the form of a bar code in the circumferential direction three times per rotation at the time of manufacture. As the characteristic data, the characteristics of the film of the disk 1 (reflectance), the power of recording and reproducing of the semiconductor laser, the format format (the number of sectors in one rotation), etc. are recorded.
The characteristic data recording area 1b, as shown in FIG.
Information is indicated by continuous or discontinuous pit rows and is recorded radially in the radial direction of the disc 1. The recording position is defined by the distance (radial position) from the center of the disc 1 (see FIG. 3). ..

As shown in FIG. 4, the characteristic data recording area 1b is composed of three sectors, and each sector has a gap, a preamble, a synchronizing signal, characteristic data,
It is composed of sectors, track address data, CRC check data, and the like.

As shown in FIG. 5, one bit of data in the characteristic data recording area 1b has a pit string of 82 bits.
When the pits are consecutive in the first half, it is determined as "0", and in the latter half, it is determined as "1".

Further, one bit of data in the characteristic data recording area 1b has 3 bits in the first half as shown in FIG.
When there are a plurality of pit strings in 28 channel bits, it is judged as "0", and when there are a plurality of pit strings in the latter half of 328 channel bits, it is judged as "1".

The data recording area 1a is divided into a plurality of sectors with the reference mark as a reference. Variable length information is recorded on a plurality of blocks on the disc 1, and 300,000 blocks are formed on the disc 1 in 36000 tracks. Recording and reproduction of information with respect to the disc 1 is performed by an optical head (moving body) 3 provided below the disc 1.

The disc 1 uses a recording film for forming pits by punching holes.
A recording film using a phase change or a multilayer recording film may be used, or a magneto-optical disk or the like may be used as the disk. In the above case, the configurations of the optical head and the like are similarly changed.

An objective lens 6 is held on the optical head 3 by a wire or a leaf spring (not shown). The objective lens 6 is moved by a driving coil 5 in the focusing direction (optical axis direction of the lens) and driven. The coil 4 allows movement in the tracking direction (direction orthogonal to the optical axis of the lens).

A shield plate 3a is provided below the optical head 3 as shown in FIG. 1 (a), and the detector 36 is shielded from light by the shield plate 3a. The detector 36 detects that the moving position of the optical head 3 is located at the innermost circumference (inner circumference end) of the disk 1 when the shield plate 3a shields the light, and the laser light from the optical head 3 is emitted. It is provided at a position where it is detected that the characteristic data recording area 1b is irradiated.

The laser light generated from the semiconductor laser oscillator 9 driven by the laser control circuit 14 is
The disc 1 is irradiated through the collimator lens 11 a, the half prism 11 b, and the objective lens 6, and the reflected light from the disc 1 is the objective lens 6 and the half prism 1.
The light is guided to the photodetector 8 via the lens 1b, the condenser lens 10a, and the cylindrical lens 10b. The photodetector 8
Is composed of four divided photodetection cells 8a, 8b, 8c and 8d.

The output signal of the photodetector cell 8a of the photodetector 8 is supplied to one end of the adders 30a and 30c via the amplifier 12a, and the output signal of the photodetector cell 8b is supplied to the amplifier 1a.
2b is supplied to one end of the adders 30b and 30d,
The output signal of the photodetection cell 8c is supplied to the other ends of the adders 30b and 30c via the amplifier 12c, and the photodetection cell 8d
Of the output signal of the adder 30a, 3a through the amplifier 12d.
It is supplied to the other end of 0d.

The output signal of the adder 30a is supplied to the inverting input terminal of the differential amplifier OP1.
The output signal of the adder 30b is supplied to the non-inverting input terminal of. As a result, the differential amplifier OP1 supplies the track difference signal to the tracking control circuit 16 according to the difference between the adders 30a and 30b. The tracking control circuit 16 creates a track drive signal according to the track difference signal supplied from the differential amplifier OP1.

The track drive signal output from the tracking control circuit 16 is supplied to the drive coil 4 in the tracking direction. Further, the track difference signal used in the tracking control circuit 16 is supplied to the linear motor control circuit 17.

The linear motor control circuit 17 responds to the track difference signal from the tracking control circuit 16 and the movement control signal from the CPU 24 to apply a voltage corresponding to the moving speed to a drive coil (conductor) 13 in a linear motor 31 described later. Is applied.

The linear motor control circuit 17 uses an electrical change inside the drive coil 13 at the moment when the drive coil 13 in the linear motor 31 described later crosses a magnetic flux generated by a magnetic member (not shown). , Drive coil 1
A speed detection circuit (not shown) for detecting the relative speed between the magnetic member 3 and the magnetic member, that is, the moving speed of the linear motor 31 is provided.

The output signal of the adder 30c is supplied to the inverting input terminal of the differential amplifier OP2, and the output signal of the adder 30d is supplied to the non-inverting input terminal of the differential amplifier OP2. As a result, the differential amplifier OP2 supplies a signal regarding the focus point to the focusing control circuit 15 according to the difference between the adders 30c and 30d. The output signal of the focusing control circuit 15 is supplied to the focusing drive coil 5 and is controlled so that the laser beam is always in perfect focus on the disc 1.

Each photodetecting cell 8a of the photodetector 8 in the state where focusing and tracking are performed as described above ,.
The sum signal of the outputs of 8d, that is, the output signals from the adders 30a and 30b, reflect the change in the reflectance from the pits (recording information) formed on the track. This signal is supplied to the signal processing circuit 19, and this signal processing circuit 1
At 9, recorded information and address information (track number, sector number, etc.) are reproduced. In addition, the laser control circuit 14
A recording signal generation circuit 34 as a modulation circuit for modulating the recording signal is provided in the preceding stage.

The reproduction signal (reproduction information) reproduced by the signal processing circuit 19 is output to the disk control device 33 as an external device through the interface circuit 32.

The video signal of the signal processing circuit 19 is supplied to the reading circuit 35. The reading circuit 35 uses the video signal from the signal processing circuit 19 to generate an envelope 2 corresponding to the recording data in the characteristic data recording area 1b.
It outputs a binarization signal, and is composed of an envelope detection circuit and an envelope binarization circuit (not shown).

Further, in this disk device, a focusing control circuit 15, a tracking control circuit 16,
A D / A converter 22 used for exchanging information between the linear motor control circuit 17 and the CPU 23 is provided.

Further, the tracking control circuit 16 is
The objective lens 6 is moved in accordance with the track jump signal supplied from the CPU 23 via the D / A converter 22, and the beam light is moved by one track.

The above laser control circuit 14, focusing control circuit 15, tracking control circuit 16, linear motor control circuit 17, motor control circuit 18, signal processing circuit 1
9. The recording signal generating circuit 44 and the like are controlled by the CPU 23 via the bus line 20, and the CPU 23 is adapted to perform a predetermined operation by a program stored in the memory 24.

When the characteristic data recording area 1b is accessed, the CPU 23 moves the optical head 3 from the innermost movable side of the optical head 3 to the outer side, and thereafter, the detector 3
When a detection signal is supplied from 6, it is determined that the moving position of the optical head 3 is located at the innermost circumference (inner end) of the disk 1. Further, the CPU 23 moves the laser light from the optical head 3 from the innermost circumference of the disk 1, and when the detection signal from the detector 36 has an intermediate value, the laser light from the optical head 3 changes the characteristic data recording area. The movement of the optical head 3 is stopped when it is determined that the light is being irradiated near the center of the radial position of 1b.

At this time, the characteristic data in the characteristic data recording area 1b is read by checking the time interval between the high level and the low level of the envelope binarized signal supplied from the reading circuit 35, and the read characteristic data is read. The control corresponding to is performed. That is, the control corresponding to the disks 1 having different specifications (company) can be performed. Next, the operation of accessing the characteristic data recording area 1b on the disc 1 in such a configuration will be described.

For example, now, the disk controller 33 issues an instruction to access the characteristic data recording area 1b to the CPU 23.
Is supplied to. Then, the CPU 23 controls the linear motor control circuit 17 to move the optical head 3 from the inside to the outside.

When the detector 36 is shielded from light by the shield plate 3a of the optical head 3, a detection signal from the detector 36 is supplied to the CPU 23. Then, the CPU 23 determines that the moving position of the optical head 3 is located at the innermost circumference (inner end portion) of the disk 1.

Further, the CPU 23 moves the laser beam from the optical head 3 from the innermost circumference of the disk 1, and the detection signal of the detector 36 has an intermediate value (between a and b shown in FIG. 1B). When it becomes (a + b) / 2), it is determined that the moving position of the optical head 3 is located at the innermost circumference of the disk 1, and the laser light from the optical head 3 is the center of the radial position of the characteristic data recording area 1b. The movement of the optical head 3 is stopped by determining that the light has been irradiated in the vicinity of the part. Here, the correction of the characteristic variation with respect to the external environment such as dust adhesion and temperature change in the detector 36 according to the disk device of the present invention will be described with reference to FIGS.

FIG. 7 schematically shows a circuit configuration for correcting the output value of the detector 36. The detector 36, the output detection circuit 51, the binarization circuit 52, the control signal generation circuit 53, and the drive circuit. 54 and a servo circuit 61.

First, the detection current 5 generated by the detector 36
5 is current-voltage converted by the output detection circuit 51. This output is the following binarization circuit 52, servo circuit 61,
And the control signal generation circuit 53. The output of the binarization circuit 52 is a binarized signal for determining whether or not the optical head 3 is within the detection range of the detector 36, that is, a head position detection signal 60. This head position detection signal 6
0 is output to the CPU 23, and the CPU 23 determines the position of the optical head 3.

The servo circuit 61 is the output detection circuit 51.
When the output value from is a constant value, the stop signal of the optical head 3 is output to the linear motor control circuit 17. Further, the servo circuit 61 starts its operation according to an instruction from the CPU 23 only when the CPU 23 determines from the head position detection signal 60 input thereto that the optical head 3 is within the innermost circumferential position control area.

The control signal generation circuit 53 is composed of an A / D converter 57 and a D / A converter 58 as shown in FIG. The output value from the output detection circuit 51 is output to the CPU 23 via the A / D converter 57, and the CPU 23 determines whether the output value is an appropriate value. If the output value is too large, the CPU 23 produces an output that lowers the output of the light source of the detector 36 to the drive circuit 54 at the next stage, and if the output value is too small, produces an output that raises it.

As a result, by controlling the light source of the detector 36, the output of the detector 36 is kept constant due to disturbance, dust adhesion, temperature, etc., and stable and reliable detection becomes possible.

Next, when the optical disk is exchanged, the disk device performs a so-called open operation (starts up to a state where information can be recorded and reproduced on the medium, and reads control information of the inserted medium). To do.

At this time, the detector 36 is controlled as follows. The optical head 3 is moved to a position where the head position detection signal 60 indicates that the optical head 3 is not present during the opening operation. At this time, the detector 36 is not shielded by the shield plate 3a of the optical head 3, and the maximum output detection current 55 of the detector 36 is output to the output detection circuit 51.

The output detection circuit 51 outputs a detection voltage 60 from the input detection current 55 to the control signal generation circuit 53. The control signal generation circuit 53 receives the input detection voltage 60.
The control signal 59 is generated so as to match the value of 1 with a predetermined specified value, and is output to the drive circuit 54.

The drive circuit 54 outputs the drive current 56 to the detector 36 in response to the input control signal 59.
The detector 36 is corrected by the input drive current 56. Thus, the next open operation is performed.

Further, the optical head 3 is usually not on the detector 36 while recording / reproducing data on the optical disk 1 or when recording / reproducing is completed, so that the above correction is made. I do.

By doing so, it is possible to correct the variation due to dust adhesion, temperature, etc., and a uniform output can be obtained from the detector 36. Further, the servo circuit 61 can control the position of the optical head 3 to the substantially central position of the detector 36 through the linear control circuit 17 with high accuracy and high reliability.

Next, the CPU 23 reads the characteristic data in the characteristic data recording area 1b by checking the time interval between the high level and the low level of the envelope binarized signal from the reading circuit 35 at this time. The control corresponding to the read characteristic data is performed. That is, the control corresponding to the disks 1 having different specifications (company) is performed. For example, the characteristics of the film of the disk 1 (reflectance), the power of the semiconductor laser for recording and reproducing, the format format (the number of sectors in one rotation), and the like are controlled by corresponding specifications.

As described above, the characteristic data recording area 1
When accessing b, move the optical head 3 from the inside,
Then, it is determined from the detection signal supplied from the detector 36 that the moving position of the optical head 3 is located at the innermost circumference of the disk 1, and the laser light of the optical head 3 is located at the radial position of the characteristic data recording area 1b. The movement of the optical head 3 is stopped when it is determined that the light has been irradiated to the central portion of the optical head 3.

As a result, by using the detector 36 for detecting the innermost circumference as the movable range of the optical head 3, the irradiation position of the laser light by the optical head 3 is determined by the characteristic data recording area 1.
Since it is aligned with the center of the radial position of b, the center of the radial position of the characteristic data recording area 1b can be accessed by a simple method.

In the above embodiment, the case where the characteristic data recording area is moved from the inside is explained, but the present invention is not limited to this, and the movement may be started from the outside or an arbitrary position.

[0056]

As described in detail above, according to the present invention,
It is possible to provide a disc device capable of performing highly reliable positioning with respect to a characteristic data recording area by using a detector for detecting the innermost circumferential position of a disc of an optical head without using a dedicated detector.

[Brief description of drawings]

FIG. 1 is a diagram showing a grounding position of a detector with respect to a disk and an optical head according to an embodiment of the present invention.

FIG. 2 is a diagram showing the configuration of a disk device according to an embodiment of the present invention.

FIG. 3 is a diagram for explaining a characteristic data recording area on the disc of FIG.

4 is a diagram showing a configuration example of 1 bit in a characteristic data recording area in the disc of FIG.

5 is a diagram showing a configuration example of 1 bit in a characteristic data recording area in the disc of FIG.

FIG. 6 is a diagram for explaining an example of the configuration of a characteristic data recording area on the disc of FIG.

FIG. 7 is a diagram showing a schematic configuration of the detector of FIG. 1 and correction.

8 is a diagram showing an example of the detector and correction circuit configuration of FIG.

[Explanation of symbols]

1 ... Disk (recording medium), 1a ... Data recording area,
1b ... Characteristic data recording area, 3 ... Optical head, 17 ...
Linear motor control circuit, 19 ... Signal processing circuit, 23 ... C
PU, 24 ... Memory, 35 ... Reading circuit, 36 ... Detector,
51 ... Output detection circuit, 52 ... Binarization circuit, 53 ... Control signal generation circuit, 54 ... Drive circuit, 55 ... Detection current, 5
6 ... Drive current, 57 ... A / D converter, 58 ... D
/ A converter, 59 ... Control signal, 60 ... Head position detection signal, 61 ... Servo circuit.

Claims (1)

[Claims] 1. A light collecting means for collecting light on a disk having a characteristic data recording area in which characteristic data as mode information is recorded, and a moving means for moving the light collecting means in a radial direction of the disk. And a light detecting means for detecting whether or not the position of the light collecting means is located at the innermost or outermost start position of the disc according to the movement of the moving means, and the light detecting means. Correction means for correcting the output value of the light detection signal to a constant value when the light collection means is not in the characteristic data recording area, and the light collection position by the light collection means using the light detection signal corrected by the correction means. Is a characteristic data recording area on the disc, and when the characteristic data recording area is accessed, the focusing means is moved by the moving means to move the radius of the disc. And a means for converging the light by the condensing means on the characteristic data recording area by stopping the movement by the moving means when the judgment result from the judging means is supplied. A disk device characterized by the above.