JPH02162537A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain an optical information recording and reproducing device capable of correcting always accurately an eccentricity by specifying an address from a value of a counter and sending out a data automatically even when a CPU is under interruption inhibition. CONSTITUTION:The data Xi corresponding to an eccentric amt. is A/D-converted and supplied to the CPU 5. The CPU 5 is interrupted by a clock signal 3 at each prescribed angle of a motor 1 so that the data Xi is fetched, and the counter 6 is counted up, and then the data is written to a dual port RAM 7a by the counter 6. At the time of writing, an arithmetic processing with prescribed conditions is carried out on the data to be stored as an error data by the CPU 5. The address error data specified by the counter 6 is read out from the RAM 7a by the clock signal 3 and latched by a latch circuit 8, and then via a D/A converter 9 the data becomes an error data Xo for correcting the eccentric amount to be injected into a servoloop. Consequently, even when the CPU is under interruption inhibition, the address is specified from the value of the counter to send out the error data of the eccentric amt. synchronized with the rotation, thus correcting accurately the eccentricity.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an optical information recording medium in which information is recorded, reproduced, and/or erased by optically irradiating a light beam onto an information recording medium. Regarding a playback device.

(Prior Art) Optical information recording and reproducing devices that record or reproduce signals using Raded light have been put into practical use. An example of this recording medium is a CD (compact disc).
, LD (LD disk), etc. Also, spiral,
Information signals are optically recorded by projecting a light beam onto a disk-shaped recording medium (hereinafter referred to as a disk) that can be recorded, reproduced, and erased using magneto-optical signals on predetermined tracks such as concentric circles.
Magneto-optical disk devices for reproducing and erasing information have also been developed.

Signals in these devices are recorded on the disk 2 by bits (not shown) (see FIG. 3).

To read information signals from the disk 2, a light beam is projected onto the disk 2 and the bits are optically scanned. That is, when a track formed in a pit is scanned by a light beam, the intensity of reflected light changes depending on the presence or absence of a pit, and information bits are optically read. In this case, it is desirable that each track on the disk 2 rotates concentrically with respect to its rotation center, but in reality, due to the eccentricity of the disk 2 itself and the eccentricity of the rotational drive system, the tracks rotate concentrically. It is common that this is not done correctly. This amount of eccentricity is about 50 to 100 μm, and as the amount of eccentricity increases, the relative speed between the head and the track increases, making it difficult to pull in the track. Alternatively, there is a problem that the residual deviation from the target track increases when surging is applied.

Therefore, in conventional devices, the following measures are taken. That is, in general, once the disk is set, the eccentricity does not vary greatly and has a certain periodicity due to rotation. From this, the amount of eccentricity is captured in synchronization with a predetermined position in one rotation, and this captured error data is added to the tracking error signal as an eccentricity correction amount in synchronization with the predetermined position from next time onward, and the apparent eccentricity is calculated. is made smaller.

In FIG. 3, xl is a point at which an amount commensurate with eccentricity is monitored, and here a value similar to the drive current t is determined.

An interrupt is applied to the central processing unit (hereinafter referred to as CPU) 5 by the spindle clock signal 3 outputted from the spindle motor 1 at every predetermined rotation angle.
The value is A/D converted by A/D converter 4 and CPU 5
The data is taken in, arithmetic processed, and stored in the RAM 7-b as error data corresponding to the rotational position of the disk 2. At this time,
At the same time, the counter 6 is activated by the spindle clock signal 3. The counter 6 is cleared every revolution, and the CPU 5 uses the value of the counter 6 to designate an address corresponding to the rotational position of the disk in the RAM 7-b.

Note that if the value of the imported Xi is significantly different from the previous data, the CPU S assumes that a noise component has been included and stops the data acquisition.

Or, to prevent sudden data fluctuations, perform arithmetic processing such as taking an arithmetic average with previous data, and then store the data in RAM.
7-b. At the same time, the CPU 5 outputs the value of the previously captured data to the D/A converter 9 via the latch 8 and applies a bias to the actuator so as to correct the amount of eccentricity. Note that at the input of the A/D converter 4 or the output of the D/A converter 9,
When adding a low or arm filter for waveform shaping, etc., in order to correct the phase delay, advance the address specified by the counter 6 by a predetermined value and output the data at that address from gAM 7-b. It is also possible to do so.

In this way, the value xl proportional to the amount of eccentricity at the rotational position is extracted and the value xl is the same as xl! . is used as a correction value to compensate for the apparent eccentricity.

(Means to be Solved by the Invention) As described above, in the conventional optical information recording/reproducing device, an interrupt is applied to the zero value at the same time as the spindle clock signal 3 is input, the A/D converter 4 captures the data, and the D/A converter Since the output is performed in 9, 1 For example, when the CPU 5 disables interrupts and wants to concentrate on processing, such as during a track jump, the error data is not updated and xg simply continues to output the previous value. Therefore, there is a drawback that accurate correction cannot be made, or in other words, output information from a corresponding address at the rotational position of the disk cannot be used. In particular, in a track jump, it is necessary to bring the relative speed close to zero just before pulling in, so although it is essential to correct the amount of eccentricity as described above, this correction is not done, causing track slippage, etc. There are some inconveniences.

Therefore, as shown in FIG. 4, the CPU is not used.

RA directly using the address of counter 6
M? Although there is a method of accessing -a to update and output data, it is not possible to correct or correct data or correct phase. Also, suppose these corrections are C
If an attempt is made to do this without using the PU, the circuit configuration will become large and it is not practical.

(Purpose of the invention) The present invention has been made based on the above circumstances.

We provide an optical information recording and reproducing device that is configured to automatically output data by specifying an address from the counter value even when interrupts are prohibited by the CPU, and that enables accurate eccentricity correction at all times. The purpose is to

(Means for Solving the Problems) Therefore, in the present invention, an information signal is optically recorded on a disc-shaped recording medium, and when the information signal is optically reproduced from the disc-shaped recording medium, The tracking error signal is taken into a central processing unit in synchronization with the rotation of the medium, and is calculated, and the calculated value is stored in a storage circuit as error data, and the error data is read out in synchronization with the rotation of the recording medium. and add it to the current tracking error signal.

In an optical information recording and reproducing apparatus that performs tracking surge control using this signal, the error data is read directly from the storage circuit using the signal from the counting means that counts the rotational position of the recording medium, and the current tracking error is measured. It is configured to be added to the signal.

(Function) Therefore, even if the CPU disables interrupts due to track jumps, etc., the address of the storage circuit is designated by the signal from the counting means, and the error data of the center quantity synchronized with the rotation of the recording medium is written out. be able to. Therefore, the eccentricity can always be corrected accurately, so that the relative speed between the head and the track can be maintained within a range where the track can be retracted without causing track slip.

(Example) Hereinafter, an example of the present invention will be specifically described with reference to the drawings. FIG. 2 shows the tracking system of the optical information recording/reproducing apparatus according to the present invention.
The detector 10 uses radar light to detect the amount of deviation of the disk (recording medium) 2 from the track guide groove as a tracking error signal.

The tracking error signal is amplified to the target r-in by the amplifier circuit 11, and compensated by the phase compensation circuit 13 so that the target phase margin is obtained. The loop switch 12 is a switch that opens or closes the tracking serge, and is opened during a track jump or the like.

The drive circuit 14 is for driving the actuator 16 in a direction that reduces the target deviation using the tracking error signal, and operates as a server when the loop switch 12 is closed.

Is CPU 17 the aforementioned tracking server? This is a processor that controls the system, and is in charge of controlling the on/off of the loop switch 12 and controlling the intake and output of error data based on the amount of eccentricity.

Moreover, xl is a point at which the drive signal is monitored, and is taken in as error data while the loop switch 12 is closed. X.

is the point at which the amount of eccentricity is injected into the tracking error signal, and is a signal almost equivalent to Xl, which can cancel out the apparent amount of eccentricity.

Figure 1 shows the process from taking in xl to outputting xo. In the A/D converter 4,
Analog data corresponding to the eccentricity of l is converted into digital data that is easy to handle by the CPU 5. Also.

The male spindle motor 1 is normally a motor that rotates at a constant rotation, and outputs a spindle clock signal 3 at every predetermined angle. For example, if the motor generates 30 clock pulses per rotation, the spindle clock signal 3 will be generated every 12 degrees of disk rotation. This spindle clock signal 3 interrupts the CPU 5, takes in the data from Xl, counts up the 30-decimal counter (counting means) 6, and the counter 6 counts up the RAM 7-a (chieral port). Specify the address. Based on this address designation, data is written into the RAM 7-a. During writing, the CPU 5 performs arithmetic processing under predetermined conditions on the data and stores it as error data. The RAM 7-a is a serial port as described above, and the write address and read address can be physically set separately. Therefore, error data at the address specified by the counter 6 is read out from the RAM 7-a and taken into the latch 8 every time the spindle clock signal 3 is output. The latched data is converted into analog data by the D/A converter 9, becomes error data x0 for correcting the amount of eccentricity, and is injected into the loop.

When writing data with the CPU 5, it is compared with the previous data value at the same address, and if it is significantly different from the current value, it is treated as noise and the previous data is left as is or As in the conventional case, calculations are performed to prevent sudden changes in data. Also.

When the CPU 5 reads the address of the counter 6, the delay of the output x0 with respect to the input Xl can be taken into account, and the phase can be adjusted such that the value of the address is specified with a delay.

As described above, according to the present invention, when the data of the input x1 is taken in and stored in the RAM, it is done through the CPU 5, but when the data is taken out from the RAM and the output x0 is output, the address value of the counter 6 is used. Since it is configured to automatically access RAM 7-a, correction data can continue to be output automatically even when the CPU is busy with processing and interrupts are prohibited, such as during track jumps. , it becomes possible to correct the amount of eccentricity accurately, and track slippage will not occur.

In the above embodiment, the spindle clock signal 3 was explained as having 30 pulses per round, but if the counter is cleared for each round, correction control can be performed in accordance with the number of clocks.

Further, in the above embodiment, the drive signal monitor x1 is used.

Sir? Although the lens was taken out immediately before the drive circuit in the loop, it goes without saying that a separately provided lens position sensor or the like may be used as long as it monitors the amount of eccentricity. In addition, although a dual port RAM is used to store data in the above embodiment, the CPU can read and write to the RAM, and it can also be read using the address of the counter 6 in synchronization with the number of clocks of the spindle clock signal 3. A general RAM may be used as long as the configuration is suitable.

(Effects of the Invention) The present invention has been described in detail above, and the error data regarding the amount of eccentricity stored in the RAM can be easily read and written via the CPU, and the counting means is synchronized with a predetermined rotational position. Since it is possible to directly access and read out RAM K, it is possible to perform calculations to cancel noise, etc., which is the function of the CPU. The amount of eccentricity can be canceled and corrected accurately, and track slippage can be prevented when the light beam is pulled in.

There is no need to increase the circuit size as in the case where a CPU is not used.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, showing the process from capturing to outputting error data regarding eccentricity, Fig. 2 is a block diagram of a tracking serge applied to the present invention, and Fig. 3 and Figure 4 are the first
FIG. 2 is a block diagram showing a conventional process corresponding to that shown in FIG. 1...Spindle motor %2...Disc, 3...
・Spindle clock signal, 4...A/D: 7n,
<-ta, 5...CPU, 6...Quantity, 7-a...
・Dual port) RAM, 8...Latch, 9...
D/A converter agent Patent attorney Johei Yamashita

Claims (1)

[Claims] When optically recording an information signal on a disk-shaped recording medium or optically reproducing an information signal from a disk-shaped recording medium, a tracking error signal is taken into a central processing unit in synchronization with the rotation of the recording medium. The calculated value is stored in the storage circuit as error data, and the error data is read out in synchronization with the rotation of the recording medium and added to the current tracking error signal, and tracking servo control is performed using this signal. In the optical information recording and reproducing apparatus, the error data is read directly from the storage circuit using a signal from a counting means for counting the rotational position of the recording medium, and is added to the current tracking error signal. An optical information recording/reproducing device characterized by: