KR100505715B1 - Method for controlling focus servo beginning and optical disk drive using the same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for controlling an optical disk drive, and more particularly, to an optical disk drive using the same, and a focus input control method for performing stable focus input control regardless of deflection of a disk.

In the disk drive control method according to the first embodiment of the present invention, (a) generating a focus actuator driving voltage for moving the lens up and down, (b) while moving the lens up and down Monitoring the number and level of pulses of a signal used for signal processing generated from the light reflected from the disk; and (c) as a result of the monitoring of step (b), the level of the signal used for the signal processing is a predetermined threshold level. If the above condition and the number of pulses is even, the focus servo control is started at a point where zero crossing occurs in the linear section of the S curve of the focus error signal.

Description

Method for controlling focus inlet and optical disk drive using the same {Method for controlling focus servo beginning and optical disk drive using the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for controlling an optical disk drive, and more particularly, to an optical disk drive using the same, and a focus input control method for performing stable focus input control regardless of deflection of a disk.

In general, an optical disc is a read-only optical disc such as a CD-ROM (Compact Disc Read Only Memory), a write-once optical disc such as a CD-R (Compact Disc Recordable), or a CD-RW (Compact Disc). -Rewritable optical discs. Such various types of discs have their respective specific uses, and are widely used in recent years. Also, with the development of large-capacity discs such as DVDs, PC data as computer peripherals have been developed as a medium for recording various video or audio data with water.

In general, the optical disk drive sequentially executes a process (①) of determining the type of the disc loaded at the initial stage of operation, a focus insertion preparation process (②), and a focus servo ON start process (③) as shown in FIG. 2. do. FIG. 3 is an enlarged view illustrating a focus drawing preparation process ② and a focus servo ON start process ③ of FIG. 2.

2 In FIG. 5, FE represents a focus error signal, FOD represents a focus actuator driving signal, and RFBS represents an RF SUM signal.

In FIG. 3, the process of preparing for focusing in and starting the focus servo ON is performed by lifting the pickup lens to the uppermost position allowed by the design (①) and lowering (②) while the focus error signal FE is zero. When the point is reached (③), it means the process of turning on the focus servo.

FIG. 4 is an enlarged view of the waveform of the focus error signal FE at the point of focus in which the focus servo of FIG. 3 is turned on.

In a normal disk, the S curve of the focus error signal FE is generated once in the process of lifting the lens of the pickup upward and once in the process of lowering the pickup lens. As shown in FIG. 8, the focus error signal is generated by inverting the phases by 180 ^O continuously.

Therefore, in designing the focus servo, the polarity of the S-curve of the focus error signal at the time of focus in is set in advance, and the focus servo control value is determined to suit the set polarity.

However, in a disc having a deflection component larger than the moving speed of the lens, as shown in P2 of FIG. The S-curve of the focus error signal at the position of turning ON has a problem in that the phase control is reversed by 180 ^O compared to the design value and the focus control is reversed, thereby failing to pull in the focus.

The technical problem to be solved by the present invention is to deflect by measuring the magnitude of the RF SUM signal and the number of pulse generation (odd or even) of the RF SUM signal (or the focus error signal) in the focus-in control process in order to solve the above problems. The present invention provides a focus input control method and an optical disk drive using the same for stably performing focus input control even on a relatively large disk.

In order to achieve the above technical problem, in the focus drive control method according to the first embodiment of the present invention, (a) generating a focus actuator driving voltage for moving the lens up and down, (b) Monitoring the number and level of pulses of a signal used for signal processing generated from the light reflected from the disk while moving the lens up and down; and (c) as a result of the monitoring in step (b), the signal used for the signal processing. If the condition that the level of is greater than the predetermined threshold level and the number of pulses is even, the focus servo control is started at a point where zero crossing occurs in the linear section of the S curve of the focus error signal.

According to a second aspect of the present invention, there is provided a focus drive control method in a disk drive control method, the method comprising: (a) generating a focus actuator driving voltage for moving a lens up and down, (b) Monitoring the level of the signal and the number of focus error signals used for signal processing generated from the light reflected from the disk while moving the lens up and down; and (c) as a result of the monitoring of step (b), Starting a focus servo control at a point where zero crossing occurs in a linear section of the S curve of the focus error signal when a condition in which the level of the signal used is greater than or equal to a predetermined threshold level and the number of the focus error signals is an even number occurs; Characterized by including.

In accordance with another aspect of the present invention, an optical disk drive includes a lens for forming an optical spot on a surface of a disk, and a plurality of light detections for detecting light reflected from the disk. Means, a signal processing circuit which combines the signals detected by the plurality of light detecting means to generate a focus error signal and a signal processing signal, and a focus actuator for moving the lens up and down when the lens is transitioned to a focus inlet mode. Generating a signal and monitoring the number and level of pulse generation of the signal processing signal to generate an S-curve of the focus error signal when a condition is generated in which the level of the signal processing signal is greater than or equal to a predetermined threshold level and the number of pulses is even. Starts focus servo control at the point of zero crossing in the linear section of And this is the equivalent of the lens corresponding to the servo control and the focus actuator drive signal to generate the focus actuator drive signal, it characterized in that it comprises a driving unit for generating a driving current for moving up and down.

In accordance with another aspect of the present invention, an optical disk drive includes a lens for forming an optical spot on a surface of a disk, and a plurality of light detections for detecting light reflected from the disk. Means, a signal processing circuit which combines the signals detected by the plurality of light detecting means to generate a focus error signal and a signal processing signal, and a focus actuator for moving the lens up and down when the lens is transitioned to a focus inlet mode. Generating a signal and monitoring the level of the signal processing signal and the number of occurrences of the focus error signal to generate a condition in which the level of the signal processing signal is greater than or equal to a predetermined threshold level and the number of the focus error signals is even; Zero crossing in the linear section of the S curve of the focus error signal A servo control unit which starts the focus servo control at the point where it is generated and generates a corresponding focus actuator driving signal and a driving unit which generates a driving current for moving the lens in the vertical direction in accordance with the focus actuator driving signal; It is done.

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

As shown in FIG. 1, an optical disk drive to which the present invention is applied includes a disk 10, a pickup 20, an R / F signal processor 30, an optical driver 40, an encoder 50, and a digital signal processor. (DSP) 60, an interface circuit (I / F) 70, a system control unit 80, a servo control unit 90, a drive unit 100, a spindle motor 110, and a sled motor 120.

In the present invention, a circuit block including an R / F signal processor 30, an encoder 50, a digital signal processor (DSP) 60, and an interface circuit (I / F) 70 will be referred to as a signal processing circuit.

First, the operation of each component is as follows.

The pickup 20 is composed of a laser diode, a plurality of photodiodes, a lens and a focus / tracking actuator for moving the lens in the vertical / horizontal direction to project the optical signal onto the disk and to detect the optical signal reflected from the disk. Run the role.

The R / F signal processing unit 30 generates a focus error signal FE and a tracking error signal TE for servo control by combining and calculating the optical signals detected by the plurality of photodiodes of the pickup 20, and also the signal. It also generates a signal used for processing. After filtering the signal used for signal processing, the signal is converted into a binary signal and output to the digital signal processing unit 60.

The optical driver 40 outputs a light quantity driving signal according to the input signal in the recording mode, and outputs a driving signal for generating a constant level of laser power in the reproducing mode.

The encoder 50 reconverts the data converted into the recording format by the digital signal processing unit 60 into a bit stream and outputs the data to the optical driver 40.

The digital signal processing unit 60 executes signal processing for restoring the binary signal input from the R / F signal processing unit 30 to the original data with its clock synchronized with phase.

The servo control unit 90 generates a tracking / focus actuator driving voltage for controlling the lens built in the pickup 20 in the horizontal or vertical direction by using the tracking error signal and the focus error signal, and moves from the seek mode to the target track. The driving voltage of the sled motor 130 for moving the pickup 20 is generated. Then, the spindle motor driving voltage for driving the spindle motor 110 is generated corresponding to the spindle motor target rotational speed determined by the system controller 80. In particular, the servo controller 90 has two methods in detail to perform the following focus in control.

The first method is to generate a focus actuator drive signal for moving the lens of the pickup 20 up and down in case of transition to the focus in mode, and monitor the number and level of pulse generation of the signal for signal processing to When a condition occurs where the level is above a predetermined threshold level and the number of pulses is even, a focus servo control is started at a point where zero crossing is performed in the linear section of the S curve of the focus error signal, and the corresponding focus actuator driving signal is generated. How to design.

The second method generates a focus actuator driving signal for moving the lens of the pickup 20 up and down when the camera moves to the focus in mode, and monitors the level of the signal processing signal and the number of occurrences of the focus error signal. When the condition of the signal processing signal level is greater than or equal to the predetermined threshold level and the number of focus error signals is even occurs, the focus servo control starts at the point where zero crossing is made during the linear section of the S curve of the focus error signal. This method is designed to generate the focus actuator driving signal.

The driving unit 100 generates driving currents for driving the spindle motor 110 and the sled motor 120 according to the driving voltage generated by the servo controller 90, and the pickup 20 focuses on the built-in lens and Generates focus / tracking actuator drive current to control tracking.

The interface circuit 70 performs a data interfacing role for data transmission / reception with the host computer 130.

The system controller 80 collectively controls the optical disk drive to suit the mode set in accordance with the key input.

Next, the focus inflow control method according to the first and second embodiments of the present invention will be described in detail with reference to the flowcharts of FIGS. 6 and 7.

First, a focus input control method of an optical disk drive according to a first embodiment of the present invention will be described with reference to the flowchart of FIG. 6.

First, it is determined whether the optical disk drive is shifted to the focus lead-in mode (S601). The focus retracting mode is a mode for executing a preparation process for starting focus servo control after determining the loaded disc at the beginning of the optical disc drive operation.

In the case where the determination result in step 601 (S601) is changed to the focus lead-in mode, the RF SUM signal pulse counter C1 (not shown in the figure) built in the servo controller 90 is turned on (S602). The RF SUM signal pulse counter C1 is a counter for counting the number of pulses of the RF SUM signal in the focus in mode. In this case, the RF SUM signal means a signal obtained by adding all optical signals detected by the plurality of photodiodes included in the pickup 20.

Then, the focus actuator is controlled to raise the lens incorporated in the pickup 20 to the highest position which is allowed in the vertical direction in the vertical direction (S603).

The focus actuator is controlled to move the lens downward after raising the lens to the highest position (S604).

It is determined whether the level of the RF SUM signal RFBS generated by the R / F signal processor 30 is equal to or greater than the threshold level value Vth while the lens is lowered (S605).

As a result of the determination in step 605 (S605), when the level of the RF SUM signal RFBS is equal to or greater than the threshold level value Vth, it is determined whether the value of the RF SUM signal pulse counter C1 corresponds to an even value (S606). This is to determine whether the focus servo is applied to the S curve of the focus error signal whose phase is inverted by the disk eccentricity. When the S-curve of the focus error signal is generated twice in the lens rising section as shown in FIG. 5 due to the disc eccentricity in the focus insertion mode, the third design phase and the inverted focus error signal generated in the lens falling section are generated. This is to prevent the focus servo from being caught at the zero crossing point (L1 in Fig. 8) of the S-curve.

As a result of the determination in step 606 (S606), when the value of the RF SUM signal pulse counter C1 corresponds to an even value, it is determined whether a zero crossing point is detected in the linear section of the S curve of the focus error signal (S607). ). This is because when the disc eccentricity is generated and the S-curve of the focus error signal is generated twice in the lens rising section, the zero crossing point of the S-curve of the focus error signal which is the same as the design phase generated fourth in the lens falling section (Fig. This is for the focus servo to be applied at L2).

As a result of the determination in step 607 (S607), if a zero crossing point is detected in the linear section of the S curve of the focus error signal, the focus servo control is turned on to execute the focus servo control routine (S608).

Therefore, in the first embodiment of the present invention, while the lens is up / down in the focus-in mode, the magnitude of the level of the RF SUM signal RFBS and the number of occurrences (odd or even) of the pulses of the RF SUM signal RFBS are combined together. By judging, it is possible to prevent the focus servo from turning on at the zero crossing point of the focus error signal whose phase is reversed.

Next, a focus in control method of the optical disk drive according to the second embodiment of the present invention will be described with reference to the flowchart of FIG. 7.

First, it is determined whether the optical disk drive is shifted to the focus lead-in mode (S701).

In the case where the determination result in step 701 (S701) is changed to the focus lead-in mode, the FE signal pulse counter C2 (not shown in the figure) built in the servo controller 90 is turned on (S702). The FE signal pulse counter C2 is a counter for counting the number of pulses of the FE signal in the focus in mode.

Then, the focus actuator is controlled to raise the lens incorporated in the pickup 20 to the highest position that is allowed in the vertical direction in the vertical direction (S703).

The focus actuator is controlled to move the lens downward after raising the lens to the highest position (S704).

It is determined whether the level of the RF SUM signal RFBS generated by the R / F signal processor 30 is equal to or greater than the threshold level value Vth while the lens is lowered (S705).

As a result of the determination in step S705 (S705), when the level of the RF SUM signal RFBS is equal to or greater than the threshold level value Vth, it is determined whether the value of the FE signal pulse counter C2 corresponds to an even value (S706).

As a result of the determination in step 706 (S706), if the value of the FE signal pulse counter C2 corresponds to an even value, it is determined whether a zero crossing point is detected in the linear section of the S curve of the focus error signal (S707). .

As a result of the determination in step 707 (S707), if a zero crossing point is detected among the linear sections of the S curve of the focus error signal, the focus servo control is turned on to execute the focus servo control routine (S708).

Accordingly, in the second embodiment of the present invention, the size of the level of the RF SUM signal RFBS and the number of occurrences (odd or even) of the pulses of the focus error signal FE are increased together with the lens up / down in the focus-in mode. By judging, it is possible to prevent the focus servo from turning on at the zero crossing point of the focus error signal whose phase is reversed.

In the first and second embodiments of the present invention, while the lens is raised to the highest position of the design, the focus is attempted while pulling down. On the contrary, the lens may be designed to attempt to enter the focus while the lens is lowered to the lowest position of the design.

The invention can be practiced as a method, apparatus, system, or the like. When implemented in software, the constituent means of the present invention are code segments that necessarily perform the necessary work. The program or code segments may be stored in a processor readable medium or transmitted by a computer data signal coupled with a carrier on a transmission medium or network. Processor readable media includes any medium that can store or transmit information. Examples of processor-readable media include electronic circuits, semiconductor memory devices, ROMs, flash memory, erasable ROM (EROM), floppy disks, optical disks, hard disks, optical fiber media, radio frequency (RF) networks, Etc. Computer data signals include any signal that can propagate over transmission media such as electronic network channels, optical fibers, air, electromagnetic fields, RF networks, and the like.

Specific embodiments shown and described in the accompanying drawings are only to be understood as an example of the present invention, not to limit the scope of the invention, but also within the scope of the technical spirit described in the present invention in the technical field to which the present invention belongs As various other changes may occur, it is obvious that the invention is not limited to the specific constructions and arrangements shown or described.

As described above, according to the present invention, the focus servo ON time is determined by considering the level of the RF SUM signal and the number of occurrences (odd or even) of the RF SUM signal (or the focus error signal) in the focus inlet mode. The deflection of H produces an effect of preventing the focus servo from being caught in the S curve of the focus error signal whose phase is inverted with the servo design specification. That is, the effect that the focus control acts inversely and fails to bring in the focus is generated.

1 is a block diagram of an optical disk drive to which the present invention is applied.

2 is a waveform diagram of main signals for explaining an initialization process of an optical disk drive.

3 is a waveform diagram of main signals for explaining a focus servo insertion process of an optical disk drive.

4 is an enlarged view of waveforms of a main signal and a focus error signal when a focus servo is applied.

5 is a diagram illustrating a phenomenon in which an S-curve of a focus error signal is generated twice in a lens rising section for focus inflow due to disc deflection.

6 is a flowchart illustrating a focus in control method according to a first embodiment of the present invention.

7 is a flowchart illustrating a focus in control method according to a second embodiment of the present invention.

8 is a diagram for describing a phase of a focus error signal generated in a focus drawing process.

Claims (8)

In the disk drive control method, (a) generating a focus actuator drive voltage for moving the lens up and down; (b) monitoring the number and level of pulses of a signal used for signal processing generated from the light reflected from the disk while moving the lens up and down; And (c) If a condition in which the level of the signal used for the signal processing is equal to or greater than a predetermined threshold level and the number of pulses is even as a result of the monitoring in the step (b) occurs, 0 in the linear section of the S curve of the focus error signal. Starting focus servo control at the point of crossing. The method of claim 1, wherein the signal used for signal processing includes a signal obtained by adding up all optical signals detected by a plurality of photodiodes. In the disk drive control method, (a) generating a focus actuator drive voltage for moving the lens up and down; (b) monitoring the level of the signal and the number of focus error signals used for signal processing generated from the light reflected from the disk while moving the lens up and down; And (c) S-curve of the focus error signal when a condition that the level of the signal used for the signal processing is equal to or greater than a predetermined threshold level and the number of the focus error signals is even as a result of the monitoring in the step (b) occurs And starting the focus servo control at a point at which zero crossing occurs during the linear interval of the focus induction control method. The method of claim 1, wherein the signal used for signal processing includes a signal obtained by adding up all optical signals detected by a plurality of photodiodes. In the disk drive, A lens for forming an optical spot on the disk surface; A plurality of light detecting means for detecting light reflected from the disk; A signal processing circuit which combines the signals detected by the plurality of light detecting means to generate a focus error signal and a signal processing signal; In the case of the transition to the focus-in mode, a focus actuator driving signal for moving the lens up and down is generated, and the number and level of pulse generation of the signal processing signal are monitored so that the level of the signal processing signal is at a predetermined threshold level. A servo control unit which starts a focus servo control at a point where 0 is crossed in the linear section of the S-curve of the focus error signal and generates a corresponding focus actuator driving signal when a condition having an even number of pulses is generated; And And a driving unit for generating a driving current for moving the lens in the vertical direction in response to the focus actuator driving signal. The optical disk drive of claim 5, wherein the signal processing signal includes a signal obtained by adding up all optical signals detected by a plurality of photodiodes. In the disk drive, A lens for forming an optical spot on the disk surface; A plurality of light detecting means for detecting light reflected from the disk; A signal processing circuit which combines the signals detected by the plurality of light detecting means to generate a focus error signal and a signal processing signal; In case of shifting to the focus inlet mode, a focus actuator driving signal for moving the lens up and down is generated, and the level of the signal processing signal and the number of occurrences of the focus error signal are monitored to increase the level of the signal processing signal. When a condition occurs that is equal to or greater than a predetermined threshold level and the number of the focus error signals is an even number, the focus servo control is started at a point where zero crossing occurs in a linear section of the S curve of the focus error signal, and the corresponding focus actuator driving signal is generated. A servo control unit for generating; And And a driving unit for generating a driving current for moving the lens in the vertical direction in response to the focus actuator driving signal. The optical disc drive of claim 7, wherein the signal processing signal includes a signal obtained by adding up all optical signals detected by a plurality of photodiodes.