JP2008176863A - Optical disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk device which can stably perform short jumping of an optical disk even when the optical disk is a relatively largely eccentric optical disk. <P>SOLUTION: A disk driving mechanism 102 drives an optical disk 101, pickup conveyance mechanisms (110, 111 and 112) move a pickup 105 including an objective lens 10 and a light receiving part 107. When a control section 130 controls the disk driving mechanism, the position of the objective lens and the pickup conveyance mechanisms, the control section measures the position of the objective lens displaced according to tracking control for each rotational phase, obtains a value for relating the displacement amount of the objective lens with the moving amounts of the pickup conveyance mechanisms, and corrects the moving target values of the pickup conveyance mechanisms based on the stored displacement amount and the relating value so that the neutral position of the objective lens comes to a control start position when track jumping to a tracing target track is started. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical disc apparatus for recording / reproducing information on / from an optical disc.

  In general, an optical disc apparatus records and reproduces information on an optical disc by moving an objective lens to a predetermined position on the optical disc and irradiating a light beam through the objective lens. When moving the objective lens to a specified position on the optical disk, the track jump with a small displacement is controlled by moving the movable part in the pickup to move the objective lens in the radial direction of the optical disk, and the track jump with a large displacement is picked up. Move itself in the radial direction of the optical disc. Thereby, an accurate track jump can be performed.

  As the structure of the movable part, the objective lens and its driving coil are often supported by a spring material, and from a neutral position where no external force acts on the spring material (hereinafter also referred to as the neutral position of the objective lens). It is possible to control movement in a predetermined range in the radial direction of the optical disc and in the direction orthogonal to the information surface.

  By the way, the optical axis of the objective lens may not coincide with the center of the light beam of the light source at the neutral position of the objective lens due to variations in the attachment position of the spring material that supports the objective lens. In this case, since it is necessary to make the optical axis of the objective lens coincide with the center of the light beam of the light source, the servo system controls the displacement amount to be zero during tracking in order to cancel the displacement amount. Therefore, a biasing force is applied to the spring material on the inner side or the outer side in the radial direction of the optical disk.

  When the spring force is applied to the spring material, when tracking control is removed and step jumping is performed, the speed differs depending on whether jumping inward or jumping outward, which may hinder step jumping.

In order to solve such a problem, when the objective lens is at the neutral position, the displacement between the optical axis of the objective lens and the center of the light beam of the light source is obtained and stored in advance, and the displacement amount is calculated. An optical disc apparatus is disclosed in which a driving amount for canceling is directly given to a driver that drives an objective lens (see Patent Document 1 below).
JP 7-21576 A (summary)

  However, in the above-described conventional optical disc apparatus, when the track trajectory that is displaced in the radial direction due to the eccentricity of the optical disc is tracked, the step jump is hindered or the tracking control is easily lost due to the biasing force acting on the spring material. It was not possible to solve the problem. This will be described below.

  In the seek operation of the optical disc apparatus, first, the track address is read in the tracking control state, and the number of tracks to be jumped is calculated based on the track address. Next, when the number of tracks is large, the pickup transfer mechanism is long-jumped with the tracking control stopped, and the pickup transfer mechanism is stopped before the target track. Next, tracking control is started to read the track address, and then a short jump is performed to reach the target track.

  On the other hand, since the optical disk has eccentricity, when the track address is read by stopping the pickup transport mechanism, the actual pull-in to the track is limited to the track whose eccentric speed is near zero. That is, in the state where the objective lens is in the neutral position, the track address of the track address is drawn into the position of the spot formed by the objective lens in the track where the outermost side or the innermost side of the track locus changing in a sinusoidal shape due to the eccentricity is located. Reading is done. Then, tracking control by the movable part is started from that position. For this reason, the spring material that supports the objective lens is biased to one of the radial directions of the optical disc within the range corresponding to the peak peak value from the outermost or innermost side of the tracking locus that changes in a sinusoidal shape with time. . At this time, a biasing force acts on either the inner side or the outer side of the optical disk in the radial direction of the spring material. As a result, in addition to hindering step jumps, tracking tends to be lost at the end of the movable range of the lens at the start of tracking control.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an optical disc apparatus capable of stably performing a short jump even if the optical disc is relatively large and eccentric.
Another object of the present invention is to provide an optical disc apparatus capable of reducing the seek time by controlling the pickup transport mechanism in a feed-forward manner.

To achieve the above object, the present invention provides a disk drive mechanism for driving a rotatably held optical disk, a light source that emits a light beam, and the light beam so as to form a spot on the information surface of the optical disk. An objective lens for focusing the light, an optical system for separating reflected light from the information surface of the optical disc from the light beam, and a light receiving unit for receiving the reflected light, and the objective lens is controlled to move at least in the radial direction of the optical disc A pickup that is supported, a pickup transfer mechanism that moves the pickup in the radial direction of the optical disc, and the disc drive mechanism, and also controls the position of the objective lens based on the output signal of the light receiving unit, In addition, the pickup transport mechanism is arranged so that the light beam reaches the target track of the optical disc. In the optical disk apparatus having a Gosuru controller,
The controller is
Means for measuring the position of the objective lens displaced in the radial direction of the optical disc in response to tracking control for tracking the track of the optical disc for each rotational phase of the optical disc;
Means for obtaining a value associating the amount of displacement of the objective lens with the amount of movement of the pickup transfer mechanism;
Means for converting the amount of displacement of the objective lens from the neutral position into the amount of movement of the pickup transfer mechanism;
Means for calculating a movement target value of the pickup transport mechanism so that the objective lens is positioned near the neutral when the spot of the light beam reaches the target track of the optical disc;
The pickup transfer mechanism is controlled using a calculation result of the calculating means.

The present invention also provides a disk drive mechanism for driving a rotatably held optical disk, a light source that emits a light beam, an objective lens that focuses the light beam so as to form a spot on the information surface of the optical disk, A pickup including an optical system for separating reflected light from the information surface of the optical disc from the light beam and a light receiving unit for receiving the reflected light, the objective lens being supported so as to be movable at least in the radial direction of the optical disc; Controlling the pickup driving mechanism for moving the pickup in the radial direction of the optical disc and the disc driving mechanism, controlling the position of the objective lens based on the output signal of the light receiving unit, and changing the light beam to the optical disc. A control unit for controlling the pickup transfer mechanism so as to reach the target track of the optical disc. In the optical disk apparatus,
The controller is
Means for switching between an initial activation state and a resume activation state;
In the initial activation state, the position of the objective lens displaced in the radial direction of the optical disc in accordance with tracking control for tracking the track of the optical disc is measured for each rotational phase of the optical disc, and the displacement of the objective lens A value for associating the amount of movement with the pickup transfer mechanism is obtained, the amount of displacement of the objective lens from the neutral position is converted into the amount of movement of the pickup transfer mechanism, and the spot of the light beam is used as a target track of the optical disc. Means for calculating a movement target value of the pickup transfer mechanism so that the objective lens is positioned near the neutral when reaching, and using the calculation result to control the pickup transfer mechanism;
When starting the track jump control for the tracking target track in the resume activation state, the objective lens is set at the start position of the track jump control based on the previously measured position for each rotation phase of the objective lens and the associated value. Means for correcting the movement target value of the pickup transfer mechanism so that the neutral position of
The pickup transfer mechanism is controlled according to the corrected movement target value.

  According to the present invention, when the track jump control for the tracking target track is started, the movement target value of the pickup transfer mechanism is corrected so that the control start position is located near the neutral position of the objective lens. Even in the case of the optical disc, the short jump can be stably performed. Further, since the pickup transport mechanism is controlled in a feedforward manner, the seek time can be shortened.

Hereinafter, the present invention will be described in detail based on preferred embodiments shown in the drawings.
<First Embodiment>
FIG. 1 is a block diagram showing a schematic configuration of a first embodiment of an optical disc apparatus according to the present invention. In FIG. 1, a flange 104 is fixed to a shaft 103 of a spindle motor 102 as a disk drive mechanism, and the optical disk 101 is detachably held by the flange 104. The spindle motor 102 is coupled with a frequency generator (not shown) that generates a pulse in accordance with its rotation, and a speed signal FG is input to the microcomputer 130 as a feedback signal for controlling the speed of the spindle motor 102. The The spindle motor 102 is speed controlled so that the linear velocity at the light spot position formed on the information surface of the optical disc 101 becomes a predetermined value. The speed signal FG is also input to the frequency dividing circuit 116, where the frequency is divided so that one pulse is generated every time the spindle motor 102 makes one rotation, and is input to the microcomputer 130 as the reference rotation phase signal REFP. The The reference rotational phase signal REFP serves as a phase reference for measuring the displacement of the objective lens 10 for each rotational phase of the optical disc 101, as will be described later.

  The pickup 105 includes a laser diode 106 as a light source that emits a light beam, an objective lens 10 that focuses the light beam so as to form a spot on the information surface of the optical disc 101, and a reflected light beam from the information surface of the optical disc 101. And an optical system 13 that separates the light from the optical system 13 and a light receiving unit 107 that receives the reflected light. The pickup 105 is connected to a female screw portion 112 mounted on the bottom thereof, a lead screw 111 screwed to the female screw portion 112, and a pickup transfer mechanism by a sled motor 110, and thereby controlled to move in the radial direction of the optical disc. It has become. The objective lens 10 and the coils 108 and 109 are integrated as a movable part, and are supported by a spring material (not shown) so as to be movable in a radial direction of the optical disc 101 and a direction orthogonal to the information surface. Then, tracking control for moving the objective lens 10 in the radial direction of the optical disk 101 by controlling the current of the coil 108 and movement of the objective lens 10 in a direction orthogonal to the information surface of the optical disk 101 by controlling the current of the coil 109 are performed. Focus control is performed.

  The light emitted from the laser diode 106 is shaped into three light beams by an optical system such as a diffraction grating (not shown). These light beams are irradiated onto the optical disc 101 through the objective lens 10 and are modulated and reflected by the recording signal and the guide groove. The reflected light is separated by the optical system 13 and enters the light receiving unit 107. As will be described in detail later, the light receiving unit 107 includes a plurality of photodiodes, and each output signal is input to the analog signal processing circuit 114. The analog signal processing circuit 114 substitutes each input signal into a predetermined arithmetic expression to generate a tracking error signal TE, a focus error signal FE, and a lens error signal LE. These error signals are converted into digital signals by the A-D converters 121, 122, and 123 and input to the microcomputer 130.

  The microcomputer 130 is pre-programmed with programs and fixed values necessary for arithmetic processing, and provided to the microcomputer 130 as needed. A RAM 132 used as a working area for the arithmetic processing of the microcomputer 130 or an input / output buffer. A flash ROM 133 for storing initial setting values and the like is attached, and a tracking error signal TE, a focus error signal FE, and a lens error signal LE converted to digital signals are input. Further, a control signal for controlling the currents of the coils 108 and 109 is output so that the TE and FE error signals are set to zero. Here, the coil 108 is connected to the microcomputer 130 via the DA converter 124 and the driver 126, and the coil 109 is connected via the DA converter 125 and the driver 127. Therefore, a control signal for moving the objective lens 10 in the radial direction of the optical disk 101 is converted into an analog signal by the DA converter 124 and applied to the driver 126. The driver 126 supplies a control current to the coil 108. A control signal for moving the objective lens 10 in a direction orthogonal to the information surface of the optical disk 101 is converted into an analog signal by the DA converter 125 and applied to the driver 127, and the driver 127 supplies a control current to the coil 109. .

  Further, a switch 117 for detecting that the pickup 105 has been moved to the radially innermost part of the optical disk 101 is provided, and the microcomputer 130 indicates that the switch 117 has been turned on. Read and detect moving to the innermost part. Further, the microcomputer 130 is configured to control the sled motor 110 via the drive circuit 113 and to control the spindle motor 102 via the drive circuit 115.

FIG. 2 is a block diagram showing the configuration of the light receiving unit 107 and the signal input / output path of the analog signal processing circuit 114. In FIG. 2, four photodiodes A, B, C, and D are arranged in the center, two photodiodes E and F are arranged on one side of these, and two photodiodes G and H are arranged on the other side. Has been. When the signals output from the photodiodes A, B, C, D, E, F, G, and H are a, b, c, d, e, f, g, and h, respectively, the analog signal processing circuit 114 is The focus error signal FE, tracking error signal TE, and lens error signal LE are generated by performing the above calculation.
FE = (a + c) − (b + d) (1)
TE = ((a + d) − (b + c)) + ((e−f) + (g−h)) (2)
LE = ((a + d) − (b + c)) − ((e−f) + (g−h)) (3)
Among these error signals, the lens error signal LE has a value proportional to the amount of movement of the objective lens 10 in the radial direction.

  FIG. 3 is an explanatory diagram of a general seek operation. As shown in FIG. 3, the seek operation first reads a track address in a normal tracking control state (abbreviated as TRON in the figure). Next, the distance to the track at the target address is calculated, and if this distance is long, a long jump is performed. In the long jump, the tracking control is stopped, the lead screw 111 is rotated so that the amount of movement of the pickup transfer mechanism obtained by calculation is reached, and the pickup 105 is moved at high speed just before the target track. Next, in the tracking control state, the track address is read, the remaining number of tracks is calculated, and a short jump is started. In the case of an optical disk with large eccentricity, speed control is easily lost when performing a short jump outside the lens position.

  FIG. 4 is an explanatory diagram for explaining the displacement state of the objective lens 10 in comparison with the present embodiment and the conventional example, together with the waveform diagram showing the timing of the track reading operation. 4A is a waveform diagram of the tracking error signal TE when tracking control is stopped, and FIG. 4B is a curve showing the displacement of the objective lens 10 when tracking control is started at time t0. It is. In FIG. 4B, the vertical axis indicates the relative value when the neutral position of the objective lens 10 is 0, the curve A indicates the displacement of a conventional general optical disk device, and the curve B indicates the present embodiment. The displacement is shown.

  Here, when using an optical disk with large eccentricity, the tracking operation is actually started after the tracking control is started, that is, when the frequency of the tracking error signal TE shown in FIG. The timings t0, t8, t16, and t24 shown in FIG. When this timing is made to correspond to the eccentricity of the optical disk, as shown in FIG. 4B, the objective lens 10 is in the vicinity of the extreme value when it is displaced to the innermost or outermost track. At this time, assuming that the objective lens 10 is in the neutral position and the track is pulled in near this extreme value, the objective lens 10 has a peak-peak value of the track as shown by a curve A in FIG. It will be displaced in the range of 0 to -2. Then, in the vicinity of -2 where the displacement is large, a large biasing force acts on the spring material as described above. Therefore, tracking becomes easy to come off, and even when a short jump occurs, the speed control is lost or a good stop is made. This is not possible and the track flow tends to occur.

  Here, the relationship between the present embodiment and the conventional apparatus will be further described with reference to FIGS. A portion generally referred to as an actuator of the pickup 105 (see FIG. 1) that moves in the radial direction of the optical disc 101 can be represented by a fixed portion 11 and a movable portion 12 as shown in FIG. If the initial positions of the fixed portion 11 and the movable portion 12 that follow the sinusoidal track locus caused by the eccentricity of the optical disc 101 are at the center position M of the track locus L as shown in FIG. Is displaced only within the range of the extreme value P1 and the extreme value P2 with the central position M as the center, so the biasing force generated in the spring material is small and has little effect on the tracking control. On the other hand, if the initial position following the track trajectory of the optical disc 101 is the extreme value P1 as shown in FIG. 7, it is generated in the spring material when the movable portion 12 is displaced to the center position M. Even if the urging force is small, it is likely to become unstable because it constantly receives the urging force of the spring material, and in particular, when trying to jump further to the inner circumference such as the extreme value P2, the probability of failing to pull into the track Becomes higher.

  In the present embodiment, the neutral position of the objective lens 10 is moved by moving the fixed portion 11 to the center position M shown in FIG. 6 before performing the short jump by the movable portion 12 at the stage of reading the track address. A displacement as shown by a curve B in FIG. 4B is made in accordance with the central position M of the track locus, and the control function thereof is provided to the microcomputer 130 associated with the ROM 131, the RAM 132, and the flash ROM 133.

  FIG. 8 is a flowchart showing a specific processing procedure of the microcomputer 130 executed at the time of activation such as after disk loading. Here, backlash of the pickup transfer mechanism is measured in step S801. This process is for improving the accuracy of the pickup movement control, and may be ignored when the backlash is small, or a fixed value may be used when it is known. Next, focus control is executed in step S802, and in a state where tracking control is stopped, the lens error signal LE is converted by the AD converter 123 and read as the position of the objective lens 10. As shown in FIG. 5, the value obtained by the A / D conversion is the neutral position of the movable portion 12 with respect to the fixed portion 11, that is, the neutral position of the objective lens 10. Next, in step S803, the eccentricity for each rotational phase of the optical disc 101 is measured. Here, the output of the AD converter 123 to which the lens error signal LE is input is sampled with respect to an arbitrary track in a tracking control state. At this time, the count value of the speed signal FG of the spindle motor 102 is taken together as rotation phase data with reference to the reference rotation phase signal REFP generated as one pulse every time the spindle motor 102 makes one rotation. For example, if the sampling values measured for each rotation phase are added over one rotation of the optical disc 101, and the value obtained by the addition is divided by the number of samplings, the displacement amount displaced in the radial direction of the optical disc 101 is calculated. An average value can be obtained.

  Next, the target lens position for each rotation phase is calculated so that the center of the track locus decentered in step S804 is the neutral position of the objective lens 10. The eccentricity measurement in step S803 described above is in the tracking control state and the pickup transfer mechanism also follows the tracking operation. This tracking operation is performed in a predetermined direction when the value of the tracking error signal TE after passing through the low-pass filter exceeds a predetermined value. The tracking error signal TE constantly includes a DC deviation. For this reason, the position of the objective lens 10 is slightly deviated from the neutral position. Therefore, in step S804, first, the sampling value for each rotational phase obtained in step S803 is averaged to calculate the center position of the objective lens 10 that is tracking the eccentric track. Next, using the difference from the lens error signal LE at the neutral position of the objective lens 10 obtained in step S802 as a position difference, the average value obtained in step S803 is corrected. A value obtained by correcting this average value is the target center lens position at the time of tracking an eccentric track.

In step S805, the relationship between the amount of displacement of the objective lens 10 and the amount of movement of the pickup transfer mechanism is determined. Here, the follow-up control by the pickup transfer mechanism is stopped, and the distance beyond the backlash is moved to the inner periphery or the outer periphery in the follow-up control state with respect to the track. That is, the screw surface in the traveling direction of the lead screw 111 is brought into a state of being pressed against the screw surface of the female screw portion 112. At this time, since the track is in a follow-up control state, the position of the objective lens 10 is moved by the amount of movement of the pickup transfer mechanism. At this stage, the lens error signal LE corresponding to the position of the objective lens 10 is measured. The measurement of the lens error signal LE may be an average value of sampling values for each rotation phase, or may be a maximum value or a minimum value of eccentricity. Next, the pickup transfer mechanism is moved in a direction opposite to that described above by a distance equal to or longer than the backlash, and the lens error signal LE is measured again. Here, the difference in the lens error signal LE measured twice is ΔLE, the number of pulses applied to the sled motor 110 when the pickup transfer mechanism is moved the second time is Pp, and the pickup transfer mechanism is moved by the amount of the backlash. If the number of pulses applied to the sled motor 110 is Pb and the amount of lens movement per pulse applied to the sled motor 110 is K, the following relationship is established.
K = ΔLE / (Pp−Pb) (4)
From this equation (4), the relationship between the measured value of the lens error signal LE and the amount of movement of the pickup transfer mechanism is obtained.

  FIG. 9 is a flowchart showing a detailed processing procedure for measuring backlash in step S801 in FIG. In this process, first, in step S901, the pickup transfer mechanism starts to move from the outside in the radial direction to the inside (from the outer periphery to the inner periphery). In step S902, the number of pulses applied to the sled motor 110 is counted (added) after the pickup transfer mechanism starts moving. Next, in step S903, it is checked whether or not the switch 117 for detecting that it has been moved to the radially innermost portion is in an off state, and if it is in an off state, the process returns to step S901. If it is further moved inward and is not in the off state, that is, if it is in the on state, the pickup transport mechanism is stopped in step S904. In step S905, counting (adding) of the number of pulses applied to the sled motor 110 is stopped. Next, in step 906, the pickup transfer mechanism starts to move from the inside in the radial direction to the outside (from the inner periphery to the outer periphery). In step S907, the number of pulses applied to the sled motor 110 is counted (subtracted) after the pickup transfer mechanism starts moving. Next, in step S908, it is checked whether or not the switch 117 is in the on state. If the switch 117 is in the on state, the process returns to step S906 to move further outward. If it is not in the on state, that is, in the off state. In step S909, the pickup transfer mechanism is stopped. In step S910, counting (subtraction) of the number of pulses applied to the sled motor 110 is stopped. Then, a value obtained by subtracting the count value of the number of pulses when the switch 117 is not in the off state from the count value of the number of pulses when the switch 117 is not in the on state is converted into the number of pulses applied to the sled motor 110. The backlash of the pick-up transfer mechanism.

  FIG. 10 is a flowchart showing a detailed processing procedure for performing thread movement measurement in step S805 of FIG. In this process, first, tracking control is started in step S1001 to start tracking for a track (TR ON). Next, it waits for the time set in the timer to elapse until the tracking control is stabilized in step S1002. Next, the pickup transfer mechanism is stopped (OFF) in step S1003. In step S1004, a predetermined number of pulses are applied to the sled motor 110 so as to move the pickup transport mechanism in the reverse direction by a predetermined distance. The predetermined number of pulses is larger than the number of pulses corresponding to the backlash of the pickup transfer mechanism. Next, in step S1005, the elapse of time set in the timer is waited until tracking control is stabilized. In step S1006, the maximum value of the lens error signal LE is measured. Next, in step S1007, a predetermined number of pulses are applied to the sled motor 110 so as to move the pickup transport mechanism in the positive direction by a predetermined distance. The predetermined number of pulses is larger than the number of pulses corresponding to the backlash of the pickup transfer mechanism. Next, in step S1008, the elapse of time set in the timer is waited until tracking control is stabilized. Next, in step S1009, the maximum value of the lens error signal LE is measured again. Next, in step S1010, a difference between measured values of the lens error signal LE is obtained, and a lens movement amount K per pulse applied to the sled motor 110 is calculated (LE sensitivity calculation) according to the above equation (4).

FIG. 11 is a flowchart showing a processing procedure for correcting the target value of the lens position immediately after starting the tracking control and immediately before shifting to the short jump after the long jump. In this process, first, the lens error signal LE is read as the lens position of the objective lens 10 in step S1101. Next, in step S1102, the step direction necessary for moving the neutral position of the objective lens 10 to approximately the center of the track locus by moving the pickup transfer mechanism and the number of pulses applied to the sled motor 110 are calculated. Specifically, when the lens error signal LE read in step S1101 is LEy and the lens error signal LE in the same rotational phase obtained by measurement in step S803 in FIG. The number of pulses Np of the sled motor 110 corresponding to the amount of movement of the pickup transfer mechanism that corrects the displacement from the center position is calculated by the following equation.
Np = (LEy−LEx) / K (5)
Here, K is a lens movement amount per pulse applied to the sled motor 110. In this case, the backlash is an error, but it is not a big problem. Next, the pickup transfer mechanism is moved according to the number of pulses Np calculated in step S1103.

  In this way, after the long jump, the objective value of the lens 10 is corrected to the neutral position by correcting the target value of the lens position by the number of pulses Np in the equation (5) immediately after the tracking control is started and immediately before the transition to the short jump. It is possible to follow an eccentric track by distributing in the radial direction. The correction of the target value will be described again with reference to FIG.

  The waveform diagram shown in FIG. 4A is a waveform diagram of the tracking error signal TE in a state where the tracking control is stopped. It is assumed that after a long seek, the tracking of the tracking error signal TE becomes a state following the track where the position of the objective lens 10 is an extreme value at time t0. If the displacement of the objective lens 10 is “1” in FIG. 4B at this time t 0, it is possible to follow the eccentric track by allocating from the neutral position in the radial direction. Therefore, if the displacement of the objective lens 10 becomes “1” at the time t16, the pulse number Np of the expression (5) is applied to the sled motor 110 between the time t0 and the time t8 to make the pickup transfer mechanism constant speed. Move with. As a result, the objective lens 10 is moved, and the neutral position is assigned to track the eccentric track. Therefore, if a short jump is performed after time t8, a good seek operation can be realized.

  FIG. 12 is a curve showing the displacement of the objective lens 10 when the tracking of the objective lens 10 is slightly deviated from the extreme value of the eccentric track. In FIG. 12, a curve A indicates the displacement of a conventional general optical disc apparatus, and a curve B indicates the displacement of the present embodiment. As can be seen from this figure, even when the track is tracked at a position slightly deviated from the extreme value of the eccentric track, a good seek operation can be realized.

  As is clear from the above description, according to the first embodiment of the present invention, the position of the objective lens 10 that is displaced in the radial direction of the optical disc 101 according to tracking control is measured for each rotational phase of the optical disc 101. Then, the displacement amount of the objective lens 10 from the neutral position is converted into the movement amount of the pickup transfer mechanism, and the pickup transfer mechanism is controlled so that the objective lens 10 distributes the neutral position and tracks the track. Therefore, even a relatively large eccentricity optical disk can be stably short-jumped, and the pickup transport mechanism is controlled in a feed-forward manner, so that the seek time can be shortened.

<Second Embodiment>
In the first embodiment described above, the average value of the displacement from the target neutral position in each rotational phase of the objective lens 10 and the displacement amount of the objective lens 10 are as follows. The coefficients indicating the relationship with the amount of movement of the pickup transfer mechanism have been calculated. However, if these values are stored in the RAM 132 attached to the microcomputer 130 in advance, the processing for obtaining these values again in the resume activation state is not performed. However, the movement target value of the pickup transfer mechanism can be calculated so that the objective lens 10 is at the neutral position.

  FIG. 13 is based on this idea, and when the activation state is the resume activation state, the average value of the displacement from the neutral position of the objective lens 10 stored in the RAM 132, the displacement amount of the objective lens 10, and the pickup transfer mechanism It is the flowchart which showed the process sequence which correct | amends the movement target value of a pick-up transfer mechanism at the time of a short jump using the coefficient which shows the relationship with a movement amount. Here, first, in step S1301, an activation state check is performed to determine whether the activation state is the initial activation state or the resume activation state. Next, in step S1302, it is determined whether or not it is in the resume activation state. If it is in the resume activation state, the average value of the displacement from the neutral position for each rotation phase stored in the RAM 132 in step S1303 and the objective lens 10 respectively. The process shown in FIG. 11 is executed by using the coefficient indicating the relationship between the displacement and the movement amount of the pickup transfer mechanism, that is, using the stored data and performing the same process as in step S805 in FIG.

  As is apparent from the above description, according to the second embodiment of the present invention, the average value of the displacement of the objective lens 10 from the neutral position, the displacement amount of the objective lens 10 and the movement amount of the pickup transfer mechanism When the track jump for the tracking target track is started in the resume activation state, the neutral position of the objective lens 10 is positioned at the control start position based on the stored average value and the associated value. In order to correct the movement target value of the pickup transfer mechanism, even a relatively large eccentricity optical disk can be stably short-jumped, and the seek time can be shortened faster than when the thread is corrected with TE. In addition, there is an effect that the initial operation is unnecessary and the startup time can be shortened.

  In each of the above embodiments, the movement target value is calculated ignoring the backlash of the pickup transfer mechanism. However, the pickup movement is corrected by correcting the movement target value in consideration of the backlash measurement value. The accuracy of control can be improved.

  The present invention provides a pickup transfer mechanism so that when the objective lens that is tracking a track moves in the radial direction due to the eccentricity of the optical disc, the neutral position of the objective lens is at the center of the displacement width of the tracking target track. Therefore, even a relatively large eccentric optical disk can be stably short-jumped, and the pickup transport mechanism is controlled in a feed-forward manner, so that the seek time can be shortened. Therefore, the present invention can be applied to various optical disk storage / playback apparatuses such as a DVD player / recorder or a BD player / recorder.

1 is a block diagram showing a schematic configuration of a first embodiment of an optical disc apparatus according to the present invention. It is the block diagram which showed the structure of the light-receiving part of 1st Embodiment, and the signal input / output path | route of an analog signal processing circuit. It is explanatory drawing of a general seek operation | movement. It is explanatory drawing for demonstrating the displacement state of an objective lens by contrasting a 1st Embodiment and a prior art example with the timing of a general track reading operation | movement. It is explanatory drawing for demonstrating the relationship with the fixed part of the movable part which tracks the track | truck of the eccentric optical disk. It is explanatory drawing for demonstrating the relationship with the fixed part of the movable part which tracks the track | truck of the eccentric optical disk. It is explanatory drawing for demonstrating the relationship with the fixed part of the movable part which tracks the track | truck of the eccentric optical disk. It is a flowchart which shows the specific process sequence of the microcomputer which comprises 1st Embodiment. It is a flowchart which shows the specific process sequence of the microcomputer which comprises 1st Embodiment. It is a flowchart which shows the specific process sequence of the microcomputer which comprises 1st Embodiment. It is a flowchart which shows the specific process sequence of the microcomputer which comprises 1st Embodiment. It is explanatory drawing for demonstrating the displacement state of an objective lens by contrasting 1st Embodiment and a prior art example. It is a flowchart which shows the specific process sequence of the microcomputer which comprises 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Objective lens 13 Optical system 101 Optical disk 102 Spindle motor (disk drive mechanism)
105 Pickup 106 Laser diode (LD, light source)
107 Light receiver (PD)
110 Thread motor (Pickup transfer mechanism)
111 Lead screw (Pickup transfer mechanism)
112 Nut (Pickup transfer mechanism)
113, 115 Driving circuit 114 Analog signal processing circuit 116 Dividing circuit 121, 122, 123 AD converter 124, 125 DA converter 126, 127 Driver (DRV)
130 Microcomputer A to H Photodiode

Claims (5)

From a disk drive mechanism that drives an optical disk held rotatably, a light source that emits a light beam, an objective lens that focuses the light beam so as to form a spot on the information surface of the optical disk, and an information surface of the optical disk A pickup including an optical system that separates the reflected light from the light beam and a light receiving unit that receives the reflected light, the objective lens being supported so as to be movable at least in a radial direction of the optical disc, and the pickup to the optical disc A pickup transfer mechanism for moving the optical disk in the radial direction of the optical disk, and the disk drive mechanism, the position of the objective lens based on the output signal of the light receiving unit, and the light beam reaching the target track of the optical disk And an optical disc apparatus including a control unit for controlling the pickup transfer mechanism. Oite,
The controller is
Means for measuring the position of the objective lens displaced in the radial direction of the optical disc in response to tracking control for tracking the track of the optical disc for each rotational phase of the optical disc;
Means for obtaining a value associating the amount of displacement of the objective lens with the amount of movement of the pickup transfer mechanism;
Means for converting the amount of displacement of the objective lens from the neutral position into the amount of movement of the pickup transfer mechanism;
Means for calculating a movement target value of the pickup transport mechanism so that the objective lens is positioned near the neutral when the spot of the light beam reaches the target track of the optical disc;
An optical disk apparatus, wherein the pickup transport mechanism is controlled using a calculation result of the calculating means. From a disk drive mechanism that drives an optical disk held rotatably, a light source that emits a light beam, an objective lens that focuses the light beam so as to form a spot on the information surface of the optical disk, and an information surface of the optical disk A pickup including an optical system that separates the reflected light from the light beam and a light receiving unit that receives the reflected light, the objective lens being supported so as to be movable at least in a radial direction of the optical disc, and the pickup to the optical disc A pickup transfer mechanism for moving the optical disk in the radial direction of the optical disk, and the disk drive mechanism, the position of the objective lens based on the output signal of the light receiving unit, and the light beam reaching the target track of the optical disk And an optical disc apparatus including a control unit for controlling the pickup transfer mechanism. Oite,
The controller is
Means for switching between an initial activation state and a resume activation state;
In the initial activation state, the position of the objective lens displaced in the radial direction of the optical disc in accordance with tracking control for tracking the track of the optical disc is measured for each rotational phase of the optical disc, and the displacement of the objective lens A value for associating the amount of movement with the pickup transfer mechanism is obtained, the amount of displacement of the objective lens from the neutral position is converted into the amount of movement of the pickup transfer mechanism, and the spot of the light beam is used as a target track of the optical disc. Means for calculating a movement target value of the pickup transfer mechanism so that the objective lens is positioned near the neutral when reaching, and using the calculation result to control the pickup transfer mechanism;
When starting the track jump control for the tracking target track in the resume activation state, the objective lens is set at the start position of the track jump control based on the previously measured position for each rotation phase of the objective lens and the associated value. Means for correcting the movement target value of the pickup transfer mechanism so that the neutral position of
An optical disc apparatus that controls the pickup transport mechanism according to the corrected movement target value.   When starting the track jump control for the tracking target track, the control unit uses the calculated movement target value after moving the pickup transfer mechanism and before starting the movement of the objective lens. The optical disk apparatus according to claim 1, wherein a pickup transport mechanism is controlled. The controller is
Means for measuring backlash of the pickup transfer mechanism;
Means for correcting the movement target value by the measured value of the backlash;
The optical disk apparatus according to claim 1, further comprising: an optical disk apparatus according to claim 1. The controller is
Means for measuring a position signal corresponding to the position of the objective lens based on an output signal of the light receiving unit in a state where the objective lens is unconstrained in a radial direction of the optical disc;
Means for correcting the movement target value by a position signal corresponding to the measured position;
The optical disk apparatus according to claim 1, further comprising: an optical disk apparatus according to claim 1.

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