KR0150979B1 - Control method and the device of focusing search for disk system - Google Patents

Abstract

The present invention relates to a method and apparatus for controlling a focusing search of a disc system. The method of controlling a focusing search according to the present invention includes controlling a disk to be rotated before starting a focusing search and then starting a focusing search. The focusing search control apparatus of the present invention is characterized in that it comprises means for measuring the rotational speed of the disk, and means for determining whether the measured rotational speed of the disk is within the standard linear speed range.

According to the present invention, the spindle control and the focusing control can be performed to minimize the focusing error due to the shaking of the disk generated by the spindle kick and to make the fast focusing OK.

Description

Method and apparatus for controlling focusing search of disk system

1 is a block diagram of a disk system.

2 is a flowchart of a focusing search control method according to the present invention;

3 is a focusing search control waveform diagram.

4 is a block diagram of a focusing search control device according to the present invention.

5 is a front view and a cross-sectional view of the spindle motor shaft according to the present invention.

6 is a pulse waveform diagram according to the rotation of the motor.

* Explanation of symbols for main parts of the drawings

41: Disc 42: Spindle Motor

43: detector 44: encoder

45: pulse counter 46: calculator

47: focusing control unit 48: system control unit

49: servo unit

The present invention relates to a disk system, and more particularly to a method and apparatus for controlling a focusing search (FOCUSING SEARCH).

In disc systems such as CD-DA, CD-I, and CD-ROM, the diameter of the disc is generally 12 cm. In these systems, when a focusing error occurs due to an impact during initial focusing and playback, the focusing search is performed by first focusing. Then, the spindle servo starts to rotate the motor to control the rotation speed of the disk to be 1.2m / sec ~ 1.4 m / sec, the system standard linear speed.

But. Since the spindle kick is performed to rotate the spindle motor after the focusing servo is turned on, focusing may become unstable due to the phenomenon that the disc surface is shaken due to the influence of the eccentricity and deflection of the disc. In particular, in a mini-disk system having a diameter of 62 mm, the focusing operation may become more unstable when the same impact is applied as in a general CD series disk having a diameter of 12 cm.

According to the related art, since the focusing search is performed and the focusing is OK, the focusing servo lube is opened, and the spindle kick is performed to rotate the spindle motor. Servo may become unstable. In addition, due to the surface vibration component of the disc itself, the vibration component of the deck, the disc mounting error, or the scratch, dust, or external impact of the disc, the focusing is not immediately performed. As a result, the focusing search is continuously performed, which makes it difficult to read data from the disc.

Furthermore, if an external shock is continuously applied to the disk system, the shock response memory unit is controlled to allow the sound to be reproduced to some extent without the audio output being interrupted, but it is usually shocked depending on the memory capacity of 1 or 4 megabytes. There was a problem that the time to respond to is limited.

Accordingly, an object of the present invention is to provide a control method for minimizing the influence of the disk shake caused by the spindle kick on the focusing search and for performing the fast focusing search.

It is another object of the present invention to provide an apparatus for controlling the start of the focusing search by finding the optimal time suitable for the focusing search by measuring the rotational speed of the disk.

The focusing search control method of the present invention for achieving the above object is characterized in that it comprises the step of controlling to start the focusing search after rotating the disk first before the focusing search.

The focusing search control apparatus of the present invention for achieving the above another object is characterized in that it comprises means for measuring the rotational speed of the disk, and means for determining whether the rotational speed of the measured disk is within the standard line speed range .

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an example of a disc system capable of recording or reproducing data on a disc. The configuration of the servo unit 18 includes a focus servo 181 which always maintains a constant distance between the signal surface of the disk and the objective lens, and a tracking servo 182 for tracking the track by moving the objective lens to perform microscopic tracking. And a feeding servo 183 for tracking the track by moving the pickup, and a spindle 184 for driving the spindle motor at a constant linear speed. Then, for recording and reproducing the disc, a spindle motor 12 for directly rotating the disc, a pickup (PICK UP) 13 for picking up the reflected light by projecting a laser to a predetermined position of the disc, and And an RF amplifier 14 for controlling the servo by amplifying the weak signal.

Upon initial power-on, the laser diode is turned on for reproducing and recording laser power, and the laser beam from the nip 13 is correctly focused on the disk reflecting surface to accurately read the information recorded on the disk. When the search is performed and the focusing is OK, the disk is forcibly rotated by performing a spindle kick, which is an operation of rotating the disk 11. Then, the tracking loop reads the data by following the disc track while rotating the disc at a constant linear speed of 1.2 m / sec to 1.4 m / sec in a CLV (CONSTANT LINEAR VELOCITY) method. The feeding motor of the feeding servo 183 moves due to the error.

2 is a flow chart of the focusing search control method according to the present invention, in order to prevent the phenomenon of focusing due to the disk shake caused by the spindle kick after the focusing search, the disk is rotated first and then the rotation speed of the disk is in a predetermined range. Try to focus after you reach. That is, when a focusing error occurs due to an impact during the initial focusing and playback (21) and the spindle motor stops, the spindle is kicked first by rotating the disk (22), and then the linear speed of the disk is measured (23). Check if it is within the range (24). Then, when the linear velocity of the disc is within the range of the standard linear velocity, the focusing search is started 25 as a ratio.

3 is a waveform diagram showing the relationship between the output signal FEO of the focusing servo loop and the output signal SPDLO of the spindle servo loop. 3A is a waveform diagram according to the prior art, and FIG. 3B is a waveform diagram according to the control method of the present invention.

Conventionally, prior to the focusing search, the level of the FEO is dropped from high (31) to the objective lens of the pickup to the lowest position, and then the focusing search (32) is started. When the FEO generates a signal of focusing OK 33, the SPDLO sends a spindle kick signal 34 to the spindle motor. That is, after the focusing OK, all the loops of the servo system are operated while rotating the spindle motor. Meanwhile, according to the present invention, the servo unit is controlled to rotate the spindle motor by sending a signal 35 for spindle kicking in SPDLO before the focusing search 37 and then start the focus search 37.

4 is a block diagram of a disk system having a focusing search control device according to the present invention. In order to measure the rotational speed of the disk, a plurality of slits are added to the spindle motor 42 axis, and the detector 43 composed of a light emitting part and a light receiving part senses a reflection amount of light that varies depending on whether the slit is present as the motor shaft rotates. In addition, the encoder 44 codes the detected signals into digital signals '1' and '0' to form continuous pulsed data. Then, the calculating unit 46 calculates the standard one rotation time determined according to the standard line speed with respect to the disc track of the focus searched position, and the pulse counter 45 counts the number of pulses generated by the encoder 44 during the standard one rotation time. Counting, and the focusing control unit 47 calculates the linear velocity of the disk at the focused position by the number of pulses counted from the pulse counter and the number of slits installed on the spindle motor shaft, so that the linear velocity of the disk is within the range of the standard linear velocity. The system controller 48 issues a command to start the focusing search to the servo unit 49 when it is judged to be authorized and the linear velocity at the position where the focusing search is within the standard linear velocity is 1.2 m / sec to 1.4 m / sec. Control it.

The detector 43 and the encoder 44 according to the present invention can be applied to the present invention by using one component such as an ASIC including two functions, and also the pulse counter 45, the calculating unit 46, and the focusing control unit. Reference numeral 47 extends the function of the conventional system control unit and can be applied to the present invention.

Then, the calculation unit 46 according to the present invention applies the present invention by directly calculating the standard one rotation time during the control by the relationship between the standard line speed for the disc track of the focus searched position and the track length of the track. It is possible to apply to the present invention by providing a data section for storing data of standard 1 rotation time for all tracks of the disc so that the data for the track can be referred to at the time of control.

5 is a cross-sectional view 5B showing a front view 5A and a-a 'cross section of a spindle moker shaft with slits for measuring the rotational speed of the disk. The slit has a structure in which at least two or more appropriate numbers are installed at equal intervals with respect to the motor axis, and the pulses can be generated as many as the number of slits in each rotation of the motor in the detector 43 and the encoder 44.

6 is a waveform diagram for explaining the change in the inner and outer circumferences of the disk with respect to the pulse per disk rotation generated by the slit provided in the spindle motor shaft. In this example, if the number of slits is five, the number of pulses generated per one revolution of the disc is five, and the time taken to generate five pulses is one revolution time in the track. Since the rotational speed of the disk is a linear speed constant method, the rotational speed of the disk is higher in the inner track of the disk, and the rotational speed decreases as the outer track becomes smaller. Therefore, one rotation time of the motor increases from the inner circumference to the outer circumference. Since the time taken to generate five pulses in FIG. 6 is shorter than the waveform A1, it can be seen that the track on which the waveform A1 is measured is the inner circumference than the track on which the waveform A2 is measured.

Therefore, the standard one rotation time for each track, which is calculated directly by the computing unit or stored in the memory unit, becomes longer from the disc inner track to the outer track due to the difference in the number of revolutions per unit time in the inner and outer circumferences of the disc. In addition, by counting the number of pulses generated during the standard rotation time, which differs depending on the position of the track, in the pulse counter, the focusing control unit may calculate the linear speed of the disk by comparing the number of pulses counted with the number of slits installed in the spindle motor.

As described above, the focusing search control method according to the present invention first rotates the disk so that the rotational speed of the disk is a standard line speed, and then checks and starts the focusing search, thereby causing the disk to shake. The spindle control and focusing control can be performed to minimize the focusing error caused by the error and to achieve the fast focusing OK.

In addition, the focusing search control apparatus according to the present invention measures the rotational speed of the disk and determines whether or not the rotational speed of the disk is within the standard line speed range, so that the focusing search can be controlled, whereby the shock corresponding memory is impacted. The focusing search is performed quickly so as not to deviate from the time range corresponding to, so that the data can be read from the disc without sound breaks.

Claims (5)

CLAIMS What is claimed is: 1. A method of controlling a focusing search for maintaining a constant distance between a signal surface of a disc and an objective lens of a pickup in case of a focusing error caused by an impact during initial focusing and playing in a disc system, the method comprising: rotating a disc; A calculation process of calculating a standard one rotation time determined according to the standard line speed for the disc track at the current pickup position; Generating a predetermined number of pulses according to the rotation of the disk, and counting the number of generated pulses during the standard one rotation time; A determination process of determining whether the linear speed of the disk calculated by the counted pulse number is within a range of a predetermined standard linear speed in the disk track; and if the linear speed of the disk is within a range of standard linear speed, focusing search is performed. A method of controlling the focusing search of a disk system, characterized in that the control process to start. In a disc system in which a disc is first rotated and a focusing search is started, a predetermined number of pulse signals are generated every revolution of the disc, and the number of pulses is measured during the standard 1 revolution time for the disc track. Speed measuring means for measuring wire speed; Linear speed determining means for determining whether the rotational linear speed of the disk measured by the speed measuring means is within a predetermined standard speed range; And control means for controlling to start a focusing search if it is determined by the linear velocity determining means that the linear velocity of the disk is within a range of the standard linear velocity. The method of claim 2, wherein the speed measuring means comprises a detector consisting of at least two thin slits at uniform intervals on a motor shaft for rotating the disk, and the amount of light reflected by rotation of the disk depending on the presence or absence of the slit. And a detector for sensing and an encoder for converting a digital signal according to the amount of reflected light to generate a pulse. 3. The linear speed judging means according to claim 2, wherein the linear speed judging means calculates a standard 1 revolution time determined according to the standard linear speed with respect to the disc track at the current pickup position, and a pulse generated by the encoder during the standard 1 revolution time. A focusing control unit that calculates a linear velocity at a position searched by the counted pulse number and the number of slit numbers of the detector, and determines whether the linear velocity of the disc is within the range of the nominal wire velocity. Focusing search control device for a disc system, characterized in that provided. 5. The apparatus of claim 4, wherein the computing unit comprises a memory unit for storing data of standard one rotation time determined according to standard line speeds for all tracks of the disc.