JPS63103472A - Rotation controller for optical disk - Google Patents

Abstract

PURPOSE:To control the rotation of an optical disk with good responsiveness in a real time, by controlling a rotating means, based on the count value of a count means, even when an optical pickup has been moved so as to cross a track. CONSTITUTION:When an optical pickup moves from the inside periphery of an optical disk to the outside periphery, a sum signal corresponding to a reflected light is outputted, and shaped to a pulse by a waveform shaping circuit 68. Also, a tracking error signal is shaped to a pulse by a waveform shaping circuit 76, and by its fall, a monostable multivibrator 78 is triggered, and when this output and the sum signal pulse are L, the number of tracks which have crossed a track address data is added by an up-down counter 70, and in accordance with a count value, a rotating speed of a motor 64 decreases. On the other hand, when said optical pickup has moved from the outside periphery to the inside peripheral direction, a monostable multivibrator 80 is triggered by a rise of an error signal pulse, and when this output and the sum signal pulse are L, the number of tracks which have crossed is subtracted by the counter 70, and the rotating speed of the motor 64 increases.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a rotation control device for an optical disk, and in particular to a CLV (Constant Linear) optical disk such as a so-called compact disk or a magneto-optical disk.
The present invention relates to a rotation control device that is controlled using the r Velocity method.

(Background Art) The applicant of the present invention has previously proposed an optical disc rotation control device based on the CLV method in Japanese Patent Application No. 151941/1982. This proposed device uses an optical disc on which a track address area has been formed in advance for each track so that the optical pickup can be read during recording or playback. The rotation of the optical disk is controlled by, for example, changing the pulse frequency.

(Problems to be Solved by the Invention) In the above-mentioned device, it is possible to accurately control the rotation of the disk when the optical pickup reads the recorded address signal in the trunk address area while tracing the guide groove. For example, when the optical pickup moves significantly during access, there is a problem that the address signal cannot be read and therefore the rotation of the disk cannot be controlled in real time. The main purpose is to enable responsive control even when the optical pickup moves significantly.
An object of the present invention is to provide a rotation control device for an optical disc.

(Means for Solving the Problems) This invention provides an optical disc in which a track address area is formed for each track, a rotating means for rotating the optical disc, an optical pick amplifier for reading the optical disc, and a signal from an optical big amplifier. address detection means for detecting track address data based on the optical pickup; pulse generation means for generating a pulse for each track based on a signal from the optical pickup when the optical pickup amplifier moves across the track; and a detected trunk. A counting means for counting the track address to which the optical big amplifier has moved in response to the pulse from the address pulse generating means, and based on the count value of the counting means,
This is a rotation control device for an optical disc, including a rotation control means for controlling a rotation means.

(Function) The optical disc is rotated by a rotating means. An optical pickup reads data recorded on an optical disk and converts it into electrical signals. The address detection means detects the track address data of the track where the optical pickup is located at that time from this electrical signal. When the optical pick amplifier moves across the trunks, the pulse generating means generates pulses corresponding to the number of trunks it has crossed, based on the signal from the optical pick amplifier.

The counting means counts, for example, increments or decrements the track address data before the optical pickup crosses the track, in accordance with the pulses from the pulse generating means, thereby counting the address of the track after the optical pickup has moved. . The count value of the counting means is therefore the exact current position of the optical pickup at that time, and the rotation control means controls the rotation means based on the count value. For example, when the optical pickup is moved from the outer circumference of the optical disc toward the inner circumference, the rotating means is controlled to rotate the optical disc faster. On the other hand, when the optical pink amplifier is moved from the inner circumference of the optical disc toward the outer circumference, it rotates the optical disc more slowly.

(Effects of the Invention) According to the present invention, even when the optical big amplifier is moved across the track, the rotation means is controlled based on the count value of the counting means, so the rotation of the optical disk is responsive. Controlled in real time. Therefore, compared to the previously proposed device, access time can be significantly reduced as a result.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

(Embodiment) FIG. 2 is a plan view showing a magneto-optical disk used in an embodiment of the present invention. The magneto-optical disk 10 includes a transparent plastic substrate 12.
2 is made of polycarbonate, acrylic (PMMA) resin, or the like. A hole 14 is bored in the center of the transparent plastic substrate 12 to serve as a positioning hole when the magneto-optical disk 10 is mounted. Then, in the donut-shaped area A,
The guide groove 16 is formed spirally or concentrically.

An enlarged cross-sectional view of the transparent plastic substrate 12 is shown in FIG. 3(A).
As shown in FIG. 1, a land is formed between the guide grooves 16 described above, and this land portion becomes a recording track 18.

A perpendicularly magnetized film 20 is formed on the surfaces of these guide grooves 16 and recording tracks 18 by sputtering, vapor deposition, or the like. This perpendicular magnetization film 20 is made of, for example, an amorphous alloy of a rare earth metal and a transition metal such as GdTbFe or TbFeCo. Further, as will be described later, when the perpendicularly magnetized film 2o is irradiated with a spot light of a laser beam, the direction of magnetization of the irradiated portion is reversed, and data is recorded by this reversal of magnetization.

Reproduction of recorded data utilizes the fact that when a laser beam is irradiated, reflected light is deflected according to the direction of magnetization.

A dielectric film 22 is coated on the perpendicular magnetization film 20 for the purpose of protecting the perpendicular magnetization film 20. The dielectric film 22 is formed to fill in the irregularities on the perpendicularly magnetized film 20, and therefore, as shown in FIG. 3(A), both surfaces of the magneto-optical disk 10 are formed as flat surfaces. During recording and reproduction, a laser beam is irradiated from the transparent plastic substrate 12 side.

In FIG. 2, an address area 24 is provided in a part of the donut-shaped area A. In this address area 24, information indicating the position of the trunk is recorded by pits. That is, in the address area 24, a series of pits 26 are provided in the guide groove 16, as shown in an enlarged view in FIG. 3(B).

An example of the format of the address data formed by the focus 26 is shown in FIG. In the address area 24, a set of the same synchronizing signal pattern 28 and track address data 30 is repeatedly recorded.

If the same track address data 30 is recorded in this manner, even if a dropout occurs at one location, the track address data will not become unplayable. As the synchronization signal pattern 28, for example, a 12-bit combination "11111111010" is recorded. Trunk address data 30 is recorded as a 5-digit BCD code, so this data is 20-bit data.

In this embodiment, biphase modulation is used to modulate the track address data recorded by the pits 26 on the guide grooves 16. According to biphase modulation, as shown in FIG. 5(b), clock reproduction becomes easy and errors can be easily detected without using an error correction code.

FIG. 6 is an illustrative diagram showing an example of an optical pickup used in an embodiment of the present invention. The optical pickup 32 is
Data recorded on the magneto-optical disk 10 described in detail with reference to FIGS. 2 and 3 is read.

During recording, the laser beam irradiated from the laser diode array 34 is first focused through the collimator lens 36, the polarizing beam splitter 38, and the collimator lens 40, and is focused as a beam spot on the magneto-optical disk 10.
irradiated on top.

The reflected light from the magneto-optical disk 10, that is, the reflected light that is deflected by the magnetization state of the perpendicularly magnetized film 20 on the recording track 18 or by the pits 26 provided in the guide groove 16, is vertically reflected and redirected to the collimator lens 40 and polarized light. passes through the beam splitter 38 and enters the 1/2 wavelength plate 42,
After further passing through the 1/2 wavelength plate 42 and being condensed by the reflected light condensing lens 44, the polarized beam splitter 46
is incident on the

A portion of the light irradiated onto the polarizing beam splitter 46 passes through the polarizing beam splitter 46 and becomes incident light on the two-split photosensor 48 . This two-split photosensor 48 is
By detecting the output difference between the divided elements, the degree to which the tracking error signal, that is, the optical pickup 32 is deviated from the guide groove 16, is detected. To that end, the outputs from the split elements of the two-split photosensor 48 are provided as re-inputs of the differential amplifier 50. Therefore, the differential amplifier 50 obtains a tracking error signal.

On the other hand, the reflected light from the polarizing beam splinter 46 passes through the cylindrical lens 52 and is then received by the 4-split photosensor 54. The output of the four-division photosensor 54 is given to the plus input (+) of the differential amplifier 56. The negative input (-) of this differential amplifier 56 has 2
The output of an amplifier 58 for amplifying the output of the split photosensor 48 as it is is provided. Therefore, the output from the differential amplifier 56 is a magneto-optical signal determined by the state of magnetization of the perpendicularly magnetized film 20.

The output terminal of the 4-split photosensor 54 is also connected to the amplifier 6.
Also given to one input of 0. And this amplifier 60
The output of the amplifier 58 is applied to the other power source. Therefore, the output of the amplifier 60 is a sum signal corresponding to the reflected light from the focus provided on the guide groove 16, that is, C
A D signal is output.

FIG. 1 is a block diagram showing one embodiment of the present invention.

The rotation control device 62 includes a frequency motor (FG motor) 64, and the rotation of the magneto-optical disk 10 is controlled by the frequency motor 64 according to the frequency of a drive signal applied thereto.

The CD signal output from the optical pickup 32 shown in FIG. 6 is applied to a demodulation circuit 66 and a waveform shaping circuit 68. When the CD signal is given to the demodulation circuit 66, the guide groove 1
The track address data recorded by the pits 26 at 6 is demodulated.

However, when the optical pickup 32 moves across the guide groove 16 due to access or the like, the track address data cannot be demodulated. The track address data demodulated by the demodulation circuit 66 is applied to the data input terminal DATA of the up/down counter 70.

On the other hand, the CD signal, ie, the sum signal, is also provided to the waveform shaping circuit 68. The pulse (sum signal pulse) corresponding to the sum signal output from this waveform shaping circuit 68 is
2 and 74, respectively. Similarly, the trunking error signal output from the differential amplifier 50 is pulsed by the waveform shaping circuit 76 and output as a tracking error signal pulse, which is applied to the trigger inputs of the two monostable multi-bi breaks 78 and 80. . The monostable multi-bye break 78 is triggered in response to the falling edge of the input pulse, and therefore, when the tracking error signal falls, a low level is obtained in the monostable multi-bye break 78. On the other hand, the monostable multi-bi break 80 is triggered in response to the rising edge of the input pulse, and therefore,
When the tracking error signal pulse falls, the output of the monostable multi-bi break 80 becomes low level.

The outputs of these monostable multibibreaks 78 and 80 are applied to the other inputs of the aforementioned Nant gates 72 and 78, respectively. Therefore, Nandogame 1 and 7
2, the up pulse as a result of NANDing the sum signal pulse output from the waveform shaping circuit 68 and the output of the monostable multi-bi break 78, that is, the optical
A pulse is obtained for each track when the knob 32 is moved from the outer circumference to the inner circumference of the magneto-optical disk, and this A-knob pulse is applied to the up-count input terminal tJP of the up-down counter 70. From Nantes Gate 74,
A down pulse as a result of NANDing the sum signal pulse output from the waveform shaping circuit 68 and the output of the Hayabusa stable multi-by-break 80, that is, when the optical pickup 32 is moved from the inner circumference to the outer circumference of the magneto-optical disk. A pulse for each track is obtained, and this down pulse is applied to the down count input terminal DOWN of the up/down counter 70.

Note that these amplifier pulses and down pulses are output only when the optical pisocqua knob 32 is moved across the guide groove 16.

The load terminal LOAD of the up/down counter 70 has
An address OK signal is given. This address OK signal, for example, a CRC signal, is provided from the demodulation circuit 66 when the address data is normally demodulated by the demodulation circuit 66. Therefore, when the address data is demodulated, the address O is applied to the load terminal LOAD.
The K signal is applied, and the track address data applied to the data input terminal DATA is loaded into the up/down counter 70 as preset data.

As described above, the amplifier down counter 70 is given an amplifier pulse or a down pulse depending on the direction in which the optical pickup 32 moves.

Therefore, the output terminal 0tJ of the up/down counter 70
Data obtained by adding or subtracting these pulses from the track address data before the optical pink-up 32 is moved is output to T.

The data output from the output terminal OUT of the up/down counter 70 is converted by a conversion circuit 82 into a synchronization signal or a frequency signal for rotating the motor, and the converted frequency signal is sent to the frequency motor 64 via a rotation control circuit 84.
becomes the drive signal.

The rotation speed of the frequency motor 64 rotates the magneto-optical disk 10, as described above. The rotation speed of the frequency motor 64 is detected by the FC coil 86 and fed back to the rotation control circuit 84 described above.

In operation, the optical bifuku asop 32 reads the magneto-optical disk 1.
0 from the inner circumference toward the outer circumference, the sum signal shown in FIG. 7(A), that is, the CD signal, is output from the output terminal of the amplifier 60 shown in FIG. This sum signal is shaped by a waveform shaping circuit 68 into a sum signal pulse as shown in FIG. 7(B).

On the other hand, the output terminal of the amplifier 50 outputs a tracking error signal as shown in FIG. 7(C). This tracking error signal is processed by the waveform shaping circuit 76 at the seventh
The signal is shaped into a trunking error signal pulse as shown in Figure (D). Monostable multi-by-break 78 is triggered in response to the fall of this tracking error signal pulse.

When the output of the monostable multivibrator 78 and the sum signal pulse are both at low level, an amplifier pulse (not shown) is obtained at the output of the Nant gate 72 and is applied to the up/down counter 70. Then, in the up/down counter 70, the track address data before the optical pickup 32 is moved.
The number of tracks crossed by 2 is added up.

As the up/down counter 700 count value increases, the frequency of the frequency signal from the conversion circuit 82 decreases accordingly, and therefore the rotational speed of the frequency motor 64 decreases. That is, when the optical pinocqua 32 is moving toward the outer periphery, the frequency motor 64 is controlled to reduce its rotational speed.

On the other hand, when the optical pickup 32 moves from the outer periphery to the inner periphery of the magneto-optical disk 10, the waveform shaping circuit 68 receives the same signal as shown in FIG. A sum signal pulse as shown in (B) is output. However, the tracking error signal output from the differential amplifier 50 has a waveform as shown in FIG. 7(C'). That is, the waveform shown in FIG. 7(C) is reversed in polarity. This tracking error signal is converted by the waveform shaping circuit 16 into a tracking error signal pulse as shown in FIG. 7(D'). The monostable multi-by-break 80 is triggered in response to the rising edge of this tracking error signal pulse. When the output of the monostable multi-by-break 80 and the sum signal pulse are both at low level, a down pulse (not shown) is obtained at the output of the Nant gate 74, and the up/down counter 70
given to. Then, the up/down counter 70
Then, the number of tracks traversed by the optical pink-up 32 is subtracted from the track address data of the track along which the optical pink-up 32 moves.

As the count value of the up/down counter 70 decreases, the frequency of the frequency signal from the conversion circuit 82 increases accordingly, and therefore the rotational speed of the frequency motor 64 increases. That is, when the optical pickup 32 is moving toward the inner circumference, the frequency motor 64 is controlled to increase its rotational speed.

Thus, according to this embodiment, the optical pink-up 32
Even when the magneto-optical disk 100 is moved across the track, the circumferential speed of the magneto-optical disk 100 follows and is controlled to be constant.

Note that the above description has been made assuming that the present invention is applied to a magneto-optical disk. However, it goes without saying that the present invention can also be applied to other so-called CD devices and other optical disk devices.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention. FIG. 2 is a plan view showing a magneto-optical disk used in this embodiment. FIG. 3 is a cross-sectional view and an enlarged view of essential parts of the magneto-optical disk shown in FIG. 2. FIG. 4 is a diagram showing an example of the data format of the track address formed in the guide groove. FIG. 5 is a timing diagram showing the principle of biphase modulation. FIG. 6 is a block diagram showing the optical pickup used in this embodiment. FIG. 7 is a waveform diagram of various parts showing the operation when the optical pickup moves across the guide groove. In the figure, 10 is a magneto-optical disk, 16 is a guide groove, 1
8 is a recording track, 26 is a pit, 32 is an optical pickup, 62 is a rotation control device, 64 is a frequency motor, 78.
80 is a monostable multi-by-break, 70 is an up/down counter, and 82 is a conversion circuit. Patent Applicant Sanyo Electric Co., Ltd. Agent Patent Attorney Yama 1) Yoshihito (and 1 other person) Mika Techi Figure 3 (A) (B) 4th LJ (a) hl+hlozioloIol (b) (C)

Claims (1)

[Scope of Claims] An optical disc in which a track address area is formed for each track, a rotation means for rotating the optical disc, an optical pickup for reading the optical disc, and a track address based on a signal from the optical pickup. address detection means for detecting data; pulse generation means for generating a pulse for each track based on a signal from the optical pickup when the optical pickup moves across the track; and the detected track. Counting means for counting track addresses to which the optical pickup has moved in response to addresses and pulses from the pulse generation means; and rotation control means for controlling the rotation means based on the count value of the counting means. An optical disc rotation control device comprising: 2. The optical pickup includes a semiconductor light emitting element, a reflected light detection means for detecting reflected light of light irradiated onto the track address area from the semiconductor light emitting element, and converting the detected reflected light into an electrical signal. 2. The optical disk rotation control device according to claim 1, further comprising an electric signal converting means for controlling the rotation of an optical disk. 3. The optical disk rotation control device according to claim 2, wherein the address detection means includes a demodulator that demodulates the track address data based on the signal from the electrical signal conversion means. 4. The pulse generating means is a first means for generating a first pulse indicating that the optical pickup is crossing a track from an inner circumference to an outer circumference of the optical disk based on two signals from the electric signal converting means. , a second means for generating a second pulse indicating that the optical pickup is crossing a track from an outer circumference to an inner circumference of the optical disk according to the two signals. Optical disk rotation control device. 5. The optical disc rotation control device according to claim 4, wherein the first and second means each include a logic gate means. 6 The counting means is configured to count the first pulse or the second pulse.
6. The optical disk rotation control device according to claim 4, further comprising a reversible counter that is incremented or decremented in accordance with the pulses of the optical disc. 7. The optical disk rotation control device according to any one of claims 1 to 6, wherein the rotation means includes a pulse motor. 8. The optical disk rotation control device according to claim 7, wherein the control means includes means for applying a pulse with a repetition frequency corresponding to the count value to the pulse motor.