WO2007125666A1 - Apparatus and method for controlling track jumping scanning, and optical disc device - Google Patents

Abstract

A track jumping scanning control section (300) in an optical disc device is provided with a header cycle calculating circuit (341A), which calculates a header cycle from a time when an optical beam is applied on a header region in a certain sector in an optical recording medium to a time when the optical beam is applied to a header region in a subsequent sector. The control section is also provided with a comparing circuit (342), which compares the length of the header cycle calculated by the header cycle calculating circuit with a time required for track jumping scanning, and a delay control circuit (343), which controls delay of starting timing of the track jumping scanning, based on the comparison results obtained from the comparing circuit.

Description

 Specification

 Technical field of track jittering scanning control device and method and optical disc apparatus

 TECHNICAL FIELD [0001] The present invention relates to an optical disc apparatus, and more particularly to a technique for controlling track jittering scanning of a light beam irradiated on an optical disc.

 Background art

 [0002] There are optical disc formats in which tracks in the circumferential direction of the disc are physically divided into a plurality of sectors, and DVD-RAM is a typical example. Furthermore, the DVD-RAM uses a land / gnoleve system, in which convex land tracks and concave groove tracks whose tracking control polarities are alternately reversed in the disk radial direction are arranged. Address information in DVD—RAM is stored in CAPA (Complementary Allocated Pit Address), which is a pit string formed between land and group, and the light beam is applied to either land or gnoleve. Can also detect the address.

 In general, in an optical disc apparatus, tracking control, which is feedback control for following the irradiation position of the light beam to the track, and a track for moving the irradiation position of the light beam to an arbitrary track of the optical disc. Track jumping control is performed in which jumping is performed one by one (see, for example, Patent Document 1). In track jumping of DVD—RAM, tracking control is stopped when CAPA is detected, acceleration control of the light beam is performed, and when a zero-cross point or extreme point of the tracking error signal is detected, the optical beacon is detected. Performs deceleration control of the system. When deceleration control is performed at the zero crossing point of the tracking error signal, the irradiation position of the light beam moves from a certain land track or gnove track to the next land track or groove track (full track jumping scan). On the other hand, when the deceleration control is performed at the extreme point of the tracking error signal, the irradiation position of the light beam moves from a certain land track or groove track to the adjacent groove track or land track (norf track tracking scanning).

Patent Document 1: Japanese Patent Laid-Open No. 7-296394 Disclosure of the invention

 Problems to be solved by the invention

 [0004] The full or half track jumping strike detects the zero crossing point or extreme point of the tracking error signal, and starts the deceleration driving of the light beam and ends. Then, tracking control is resumed when the track jittering scanning is completed. As a result, the irradiation position of the light beam is feedback controlled so as to follow the destination track, and the light beam is drawn into the target track. However, if the light beam irradiation position reaches CAPA during track jumping and when tracking control is restarted, the tracking error signal is disturbed, and the zero-cross point or extreme point of the tracking error signal cannot be detected correctly. Or, tracking control may become unstable. In this way, the zero-cross point or extreme point of the tracking error signal cannot be detected correctly and the timing of the light beam deceleration control is incorrect, or the tracking control is in a transitional state immediately after the tracking control is resumed, so that the control remaining. At this time, if the disturbance due to CAPA is superimposed, the light beam cannot be stably drawn into the target track. As a result, it may take time to pull in the track, and in some cases, the track pull-in may fail.

[0005] In view of the above problems, the present invention relates to an apparatus for performing track jumping striking control of a light beam irradiated to an optical recording medium having a plurality of sectors physically separated in one track. Therefore, it is an object to realize a track jumping strike that can perform decelerating control of the light beam at the end of the track jumping strike at an appropriate timing and that can stably perform tracking control. Another object of the present invention is to provide an optical disk device provided with such a track jittering scanning control device.

 Means for solving the problem

[0006] In order to solve the above-mentioned problems, the means taken by the present invention is to perform track jumping of a light beam applied to an optical recording medium having a plurality of sectors physically separated in one track. As a control device, a header period calculation circuit that calculates a header period from when a light beam is applied to the header area of a certain sector in the optical recording medium until it is applied to the header area of the next sector, and a header period calculation circuit Comparison between the comparison circuit that compares the calculated header period and the time required for track jumping scanning, and the comparison circuit Based on the result, it is assumed that a delay control circuit that performs delay control of the start timing of track jittering scanning is provided.

 [0007] According to this, the header period from when the light beam is applied to the header area of a certain sector in the optical recording medium until it is applied to the header area of the next sector is calculated by the header period calculation circuit, and is compared by the comparison circuit. The calculated header period is compared with the time required for track jumping scanning, and the delay control circuit performs delay control of the start timing of track jumping scanning based on the comparison result. Therefore, the start timing of the track jumping scan is delayed as appropriate so that the tracking error control during tracking jumping can detect the zero-cross point or extreme point of the tracking error signal, or the track can be tracked by tracking control after tracking jumping. During the pull-in, the light beam irradiation position can be prevented from reaching the header boundary, and the light beam decelerating control at the end of track jumping can be performed at a precise timing. In addition, tracking control after track jumping can be performed stably.

 [0008] Specifically, the delay control circuit delays the start timing of the track jumping run when the comparison result of the comparison circuit indicates that the header period is smaller than the time required for the track jumping scan. . Here, preferably, the delay control circuit delays the start timing of the track jittering scan by a delay amount corresponding to the header period, and more preferably, when the header period is within a predetermined range, the header period The delay amount is changed according to Preferably, the delay control circuit delays the start timing of track jittering scanning by a delay amount corresponding to the zone irradiated with the light beam in the optical recording medium, and more preferably, the zone is within a predetermined range. The delay amount is changed according to the zone.

[0009] More specifically, the header period calculation circuit confirms that the light beam is applied to the header area of the sector in the optical recording medium based on the reflected light of the light beam from the optical recording medium. It has a header detection circuit to detect, and a timer that outputs a timer value and initializes timer operation when the header detection circuit detects light beam irradiation on the header area. Alternatively, the header period calculation circuit detects that the light beam is applied to the header area of the sector in the optical recording medium based on the reflected light of the light beam from the optical recording medium. Required for counting a predetermined number of FG signals output from a motor that rotates the optical recording medium, and a counter that counts the number of times the header detection circuit detects the light beam irradiation to the header area. It has a timer that measures time and a divider that divides the timer value by the count value of the counter. Alternatively, the header period calculating circuit detects a zone in the optical recording medium that is irradiated with the optical beam from a transfer control signal of the optical head that irradiates the optical beam, and a motor that rotationally drives the optical recording medium. A timer that measures the time required to count a predetermined number of FG signals output from the data, and a divider that divides the timer value by the number of sectors per track in the zone detected by the zone detection circuit. Have.

 On the other hand, the means taken by the present invention is an optical disk device that reads or writes information by irradiating an optical recording medium having a plurality of sectors physically separated in one track with a light beam. The track jumping control unit for controlling the track jumping of the light beam and the tracking control unit for controlling the tracking of the light beam according to the control by the track jumping scanning control unit are provided. The scissor control unit includes a header period calculation circuit that calculates a header period from when the optical beam is applied to the header area of a certain sector in the optical recording medium to the header area of the next sector; A comparison circuit that compares the header period calculated by the header period calculation circuit with a predetermined value, and a track based on the comparison result of the comparison circuit. It shall have a delay control circuit for performing delay control of the start timing of Yanbingu scan.

[0011] According to this, in the track jumping carriage control unit, the header period from when the light beam is applied to the header area of a certain sector on the optical recording medium to when the header area of the next sector is applied is determined by the header. The period is calculated by the period calculation circuit, and the comparison circuit compares the calculated header period with the time required for track jittering scanning. Based on the comparison result, the delay control circuit performs track jittering scanning. Delay control of the start timing is performed, and after track jumping, tracking control of the light beam is performed by the tracking control unit. Therefore, the start timing of the track jumping scan is delayed as appropriate to detect the zero crossing point or extreme point of the tracking error signal during the track jumping run, or after the track jumping run. The beam irradiation position does not reach the header boundary, and the light beam deceleration control at the end of the track jittering scan can be performed at an accurate timing. Tracking control can be performed stably.

 [0012] Further, in order to solve the above-mentioned problem, the means taken by the present invention is a track jumping scan of a light beam irradiated on an optical recording medium having a plurality of sectors physically separated in one track. A first step of calculating a header period from when the light beam is applied to the header area of a certain sector in the optical recording medium until it is applied to the header area of the next sector; Based on the comparison result in the second step, which compares the header period calculated in step 1 and the time required for track jumping scan, and the comparison result in the second step, the start timing of the track jumping scan And a third step for delay control.

 [0013] According to this, the header period from when the light beam is applied to the header area of a certain sector in the optical recording medium until it is applied to the header area of the next sector is calculated, and the calculated header period and A comparison is made with the time required for the track jittering scan, and the delay control of the start timing of the track jittering scan is performed based on the comparison result. Therefore, the start timing of the track jumping scan is appropriately delayed to detect the zero cross point or extreme point of the tracking error signal during track jumping, or when the track is pulled in by tracking control after the track jumping scan. The beam irradiation position can be prevented from reaching the header boundary, the light beam decelerating control at the end of the track jittering scan can be performed at an accurate timing, and the track jittering scan can be performed. Later tracking control can be performed stably.

[0014] Specifically, in the third step, when the comparison result in the second step shows that the header period is smaller than the time required for the track jumping scan, the track jumping scan Delay the start timing. Here, preferably, in the third step, the start timing of the track jittering scan is delayed by a delay amount corresponding to the header period. More preferably, when the header period is within a predetermined range, the header period is set to the header period. The delay amount is changed accordingly. Preferably, in the third step, when the zone is within a predetermined range, the delay amount is changed according to the zone, and more preferably, the zone is changed. When within the predetermined range, the delay amount is changed according to the zone.

 [0015] More specifically, in the first step, based on the reflected light of the light beam from the optical recording medium, it is detected that the light beam is applied to the header area of the sector in the optical recording medium. And a fifth step for outputting a time measurement value and initializing the time measurement operation when the irradiation of the light beam to the header area is detected in the fourth step. . Alternatively, the first step is based on the reflected light of the light beam from the optical recording medium. The fourth step detects that the light beam has been applied to the header area of the sector in the optical recording medium. The fifth step of counting the number of times of detection of light beam irradiation to the header area in this step and the time required to count a predetermined number of FG signals output from the motor that rotates the optical recording medium are measured A sixth step and a seventh step of dividing the time measurement value in the sixth step by the count value in the fifth step. Alternatively, the first step includes a fourth step of detecting a zone where the light beam is irradiated on the optical recording medium from a transfer control signal of the optical head that irradiates the light beam, and a motor that rotationally drives the optical recording medium. The fifth step for measuring the time required to count a predetermined number of FG signals output from the FG signal and the time measurement value in the fifth step are the sectors per track in the zone detected in the fourth step. And a sixth step of dividing by a number.

 The invention's effect

 As described above, according to the present invention, the zero crossing point or the extreme point of the tracking error signal during track jumping can be detected with high accuracy, and the light beam deceleration control at the end of the track jumping can be performed. Can be performed at an accurate timing. In addition, tracking control after track jumping is stably performed, and jumping and pulling into a target track is performed more quickly and reliably.

 Brief Description of Drawings

 FIG. 1 is a configuration diagram of an optical disc device according to a first embodiment.

 FIG. 2 is a diagram showing the surface structure of an optical disc.

 FIG. 3 is a flowchart of track jittering scanning.

[Fig. 4] Fig. 4 shows various signals when the start timing of track jittering scanning is delayed. It is a waveform diagram.

 FIG. 5 is a graph showing the relationship between the light beam irradiation position in the disk radial direction and the rotation control characteristics.

 FIG. 6 is a configuration diagram of an optical disc device according to a second embodiment.

 FIG. 7 is a graph showing the relationship between various signals in the header cycle calculation circuit in FIG.

 FIG. 8 is a configuration diagram of an optical disc device according to a third embodiment.

 Explanation of symbols

[0018] 200 tracking controller

 300 Track-jumping scanning control unit (track-jumping scanning control device)

 341A, 341B, 341C Header period calculation circuit

 3411 Header detection circuit

 3412, 3414 timer

 3413 counter

 3415 Divider

 3416 Zone detection circuit

 342 Comparison circuit

 343 Delay control circuit

 BEST MODE FOR CARRYING OUT THE INVENTION

The best mode for carrying out the present invention will be described below with reference to the drawings.

 [0020] (First embodiment)

FIG. 1 shows the configuration of the optical disc apparatus according to the first embodiment. This optical disc apparatus irradiates the optical beam to the optical disc and receives the reflected light or transmitted light. The disc / head unit 100, a circuit for realizing tracking control by digital control, and an address for reading The tracking control unit 200 is composed of a circuit, and the track jumping strike control unit 300 (corresponding to the track jumping strike control device) for performing track jumping scanning for each track is composed of three main components. Become. Below, each component A detailed configuration and operation will be described.

 [0021] <Disk / head unit 100>

 The disc / head unit 100 includes an optical disc 103 that is an information recording medium, a disc motor 104 that rotationally drives the optical disc 103, an optical head 109 that irradiates the optical disc 103 with a light beam, and a transfer motor 113 that transports the optical head 109. Is done. The optical disk 103 is, for example, a DVD-RAM. The optical head 109 can apply a force S to move the light beam in the radial direction of the disk 103. Further, from the position of the optical head 109, the zone where the optical beam is irradiated on the optical disc 103 can be obtained.

 FIG. 2 shows an example of the surface structure of the optical disc 103. The optical disk 103 is divided into a plurality of zones from the inner periphery side toward the outer periphery side in a concentric or spiral shape with respect to the center of the disk. Each zone is composed of a plurality of tracks, and the gnollets and land tracks are alternately arranged in the disk radial direction. Each track is divided into a plurality of sectors in the disk circumferential direction. Each sector is composed of a header area followed by a groove or land track which is a recording area. In the header area, CAPA consisting of pre-pits in physical sector units is formed in advance. The CAPA is composed of first and second header parts PID1, 2 and third and fourth header parts PID3, 4. FIG. 2 representatively shows the (m−2) th sector, the (m−l) th sector, the (m−th) sector, and the (N + 2) th to (N−4th) th tracks in each sector. The optical disk 103 shown in FIG. 2 has a spiral track, and the polarity of tracking control is reversed at the boundary between the m-l sector and the m-th sector when the disk rotates.

Returning to FIG. 1, the optical head 109 includes a light source 105 such as a semiconductor laser, a coupling lens 106 into which a light beam output from the light source 105 is incident, a polarization beam splitter 107, a quarter-wave plate 108, A focusing lens 110, a tracking actuator 111, and a two-divided photodetector 112 on which the reflected light of the optical disk 103 is incident are provided. The tracking actuator 111 includes a movable part having a tracking coil and a fixed part (both not shown) having a permanent magnet. The focusing lens 110 is attached to the movable part of the tracking actuator 111. The two-divided photodetector 112 has a light receiving region divided into two, and the direction of the dividing line is opposed to the track direction on the light receiving surface. In addition, The optical head 109 may not include all the above-described components.

The optical disk 103 is driven to rotate at a predetermined rotational speed by a disk motor 104. The light beam output from the light source 105 is collimated by the coupling lens 106, passes through the deflecting beam splitter 107 and the 1Z4 wavelength plate 108 in this order, and is focused and irradiated onto the optical disk 103 by the focusing lens 110. The The reflected light of the optical beam irradiated on the optical disk 103 passes through the focusing lens 110 and the quarter-wave plate 108 in order, is reflected by the deflecting beam splitter 107, and is then irradiated on the two-split photodetector 112. The two light receiving areas of the two-split photodetector 112 each output the irradiation light converted into an electrical signal to the tracking control unit 200. The irradiation position of the light beam on the optical disk 103 can be adjusted by the transfer motor 113 and the tracking actuator 111. The transfer motor 113 can move the entire optical head 109 in the radial direction of the optical disk 103. The tracking inductor 111 uses the electromagnetic force generated according to the current flowing in the coil of the moving part to change the relative position of the fixed part with respect to the permanent magnet, thereby changing the radial direction of the optical disc 103, that is, across the track. It is possible to move the light beam in the direction of the movement. The transfer motor 113 is used for transferring the entire optical head 109 in the radial direction of the disk, and the tracking actuator 111 is used for moving the light beam for each track.

[0025] <Tracking control unit 200>

 The tracking control unit 200 includes a circuit for tracking control and a circuit for address reading. Circuits for tracking control include differential circuit 214, sample / hold circuit 215, A / D converter 216, tracking polarity inversion circuit 217, phase compensation circuit 218, pulse width modulation circuit 219, low-pass filter 220, And switch 221 for on / off control of tracking control.

The differential circuit 214 receives the respective output signals corresponding to the two light receiving regions of the two-split photodetector 112, and generates a signal S1 representing a tracking error by a push-pull method. The sample Z hold circuit 215 samples the signal S1 only for the time required for A / D conversion by the AZD converter 216, and holds the sampled signal. The A / D converter 216 converts the held signal into a digital signal. Tracking polarity reversal times The path 217 inverts the output signal of the A / D converter 216 in accordance with a signal S6 output from the jittering control circuit 328 described later. The phase compensation circuit 218 performs phase compensation of the output signal of the tracking polarity inversion circuit 217 that stabilizes the tracking control. The pulse width modulation circuit 219 receives the output of the phase compensation circuit 218, performs pulse width modulation with a period equal to the A / D conversion period (T1) of the AZD converter 216, and outputs the result. The low-pass filter 220 plays the role of converting the output of the pulse width modulation circuit 219 into an analog signal, and its cutoff frequency (f 1) is the A / D conversion frequency (1 ZT 1) of the AZD converter 216. Is set to be smaller than (fl <l / Tl). The switch 221 opens and closes according to a signal S5 output from a search circuit 327 described later. When the switch 221 is in the conductive state, the tracking control is effective, and the output of the low-pass filter 220 is given to the tracking actuator 111 through the adder circuit 222. Therefore, when the switch 221 is in the conductive state, the light beam is feedback-controlled so that it is always located at the approximate center of the track.

 On the other hand, a circuit for reading an address includes an adding circuit 225 and an address reading circuit 226. The adder circuit 225 receives the respective output signals corresponding to the two light receiving regions of the two-split photodetector 112, adds them, and outputs a signal representing the reflected light amount sum. The address reading circuit 226 reads address information provided in each track of the optical disc 103 from the output signal of the adder circuit 225 and outputs a signal indicating the address to a search circuit 327 described later.

 [0028] <Track Jeanning Scanning Control Unit 300>

 The track jumping scanning control unit 300 includes a difference circuit 323, a trigger signal output circuit 324, a search circuit 327, a jumping stir control circuit 328, an acceleration drive pulse generation circuit 329, a deceleration drive pulse generation circuit 330, a differential circuit 331, and a jumping circuit. It consists of a direction inversion circuit 332, a header period calculation circuit 341A, a comparison circuit 342, a delay control circuit 343, and a switch 350 for switching between half-track jumping and full-track jumping scanning. The header cycle calculation circuit 341A includes a header detection circuit 3411 and a timer 3412.

[0029] The header detection circuit 3411 detects that the light beam has been applied to the header area of the sector in the optical disc 103 from the output signal of the addition circuit 225, and outputs a signal S30. Thailand When the ma 3412 detects the rising edge of the signal S30, it outputs the timer value at that time, initializes the timer operation, and resets the time. That is, the timer value output from the timer 3412 corresponds to the header period from when the light beam is applied to the header area of a certain sector on the optical disc 103 until the header area of the next sector is applied. The comparison circuit 342 compares the timer value output from the timer 3412 with the time required for track jumping running (for example, full track jumping running). Based on the comparison result of the comparison circuit 342, the delay control circuit 343 outputs a signal indicating the amount of delay of the start timing of track jittering scanning. This delay amount may be a fixed value or a variable value that changes according to the header period. In the case of the variable value, the delay control circuit 343 receives the timer value from the timer 3412 and changes the delay amount according to the timer value.

 [0030] The search circuit 327 is based on the relative positional relationship between the address of the target track input from the microcomputer 400 and the address of the current track input from the address reading circuit 226. Select one of Bing Scan and Half Track Jumping Scan. Then, the search circuit 327 sends a signal S4 for instructing the start of the jumping scan to the jumping scan control circuit 328, a signal S32 for controlling the switching between the full track jumping scan and the half track jumping scan to the switch 350, and turns on / off tracking control. The signal S5 for controlling off is output to the switch 221 and the signal S3 for controlling the track jittering direction is output to the jumping direction inversion circuit 332, respectively.

 The difference circuit 323 outputs the difference between the outputs of the A / D converter 216. The switch 350 inputs the output of either the A / D converter 216 or the difference circuit 323 to the trigger signal output circuit 324 in accordance with the signal S32. Based on the input signal, the trigger signal output circuit 324 detects a tracking error as a zero-cross point or an extreme point, and outputs a signal S8.

[0032] Upon receiving the signal S4, the jumping carriage control circuit 328 sends the signal S11 instructing the start of acceleration driving of the light beam to the acceleration driving node generation circuit 329, and switches between land tracks and group tracks (with tracking polarity Switching signal) S6 is output to the tracking polarity inversion circuit 217. Upon receiving the signal S11 1, the acceleration drive pulse generation circuit 329 drives the pulse signal S7 for accelerating the light beam to the non-reverse input terminal of the differential circuit 331, and decelerates the signal S12 indicating the end of acceleration drive. In the pulse generation circuit 330, Output each. When the deceleration drive pulse generation circuit 30 receives the signal S8 in a state where the acceleration drive is completed, that is, in a state where the signal S12 is received, the delay drive pulse generation circuit 30 generates a differential signal S9 for driving the light beam at a reduced speed. Output to the inverting input terminal of. The jamming direction inversion circuit 332 inverts the output of the differential circuit 331 in accordance with the signal S3 and outputs the result to the addition circuit 222. The deceleration drive pulse generation circuit 330 outputs a signal S13 indicating the end of deceleration drive to the jumping running control circuit 328. The light beam is moved to the next track by the no-less output by the acceleration drive pulse generation circuit 329 and the deceleration drive panel generation circuit 330. When receiving the signal S13, the jumping running control circuit 328 outputs a signal S10 indicating the end of the jumping scan to the search circuit 327.

 A process flow of track jittering scanning in the optical disc apparatus will be described with reference to FIG. When a search command is issued from the microcomputer 400 to the search circuit 327, the number N of track jumping tracks is calculated (step S101). The number N of jumping runs can be calculated from the difference between the current address and the target address, for example. When the number of jumping scans N is even (NO in step S102), that is, when jumping from one land track or groove track to another land track or groove track, the number of full track jumping scans Nf is N / 2. The number Nh of half track jumping runs is set to 0 (step S103). On the other hand, when the number of jumping scans N is an odd number (YES in step S102), that is, when jumping from one land track or gnolling track to another gnolling track or land track, the number of full track jumping scans Nf is (N —L) The number of half track jumping runs Nh is set to 1 at / 2 (step S104). After that, the full track jumping run is executed as many times as the number of full jumping runs Nf set in step S103 or S104, and then the number of half jumping runs is run as many times as Nh. A track jumping run is executed (step S105), and the track jumping run ends. Note that while the track jittering scan is being executed in step S105, the delay control circuit 343 appropriately controls the delay of the track jittering scan.

Returning to FIG. 1, the delay control of the start timing of the track jumping scan by the track jumping carriage control unit 300 will be described. The search circuit 327 is a delay control circuit 343. The start of the track jittering scan is delayed by the delay amount indicated by this signal. For example, if 200 μsec is required for full-track jittering scanning, the delay amount may be set to zero if the header period is greater than 200 / sec. If the amount of delay is zero, track jumping starts at the normal timing, ie without any delay. On the other hand, when the header period is 200 μs or less, the delay amount is set to 80 μs, for example. As a result, when light beam deceleration control is started at the end of track jumping (when the light beam reaches the center of the land track shown in Fig. 4) or after track jumping, The irradiation position does not reach the sector boundary. Therefore, the light beam decelerating control at the end of track jumping can be performed at the correct timing, and stable pull-in to the target track becomes possible (see Fig. 4).

 [0035] The delay amount may be variable according to the header period. FIG. 5 is a graph showing the relationship between the irradiation position of the light beam in the disc radial direction and the rotation control characteristics. Figure 5 (a) shows the relationship between the irradiation position of the optical beam and the disc rotation speed. Figure 5 (b) shows the relationship between the irradiation position of the light beam and the linear velocity. Figure 5 (c) shows the relationship between the irradiation position of the light beam and the header period. Figure 5 (d) shows the relationship between the irradiation position of the light beam and the amount of delay in the start timing of track jittering scanning. According to the rotation control example shown in FIG. 5, the rotation speed is constant RPM1 from the first zone to the tenth zone, gradually decreases after the tenth zone, and becomes RPM2 in the fifteenth zone. Correspondingly, the linear velocity gradually increases from LV1 of the first zone to the tenth zone, and becomes a constant Lv2 after the tenth zone. The header period gradually decreases from the 300 μs force in the 1st zone to 100 μs in the 10th zone, and is constant after the 10th zone. Thus, in the example of rotation control shown in FIG. 5, the rotation speed is constant control (CAV control) from the first zone on the inner circumference side to the tenth zone on the outer circumference side, and the inner circumference from the 10th zone onwards. This is a control (CLV control) for gradually decreasing the rotational speed from the outer circumference to the outer circumference. Since this rotation control is partly CAV control, it is called the CAV (Partial Constant Angular Velocity) method.

In the case of the rotation control example shown in FIG. 5, if 200 μsec is required for full track jumping scanning in this optical disc apparatus, the first to fifth zones where the header period is longer than 200 μsec Set the delay amount to zero. On the other hand, after the 10th zone where the linear velocity is constant and the header period is constant 100 μs, the delay amount is set to the maximum value of 80 μs. The From the 5th zone to the 10th zone, the delay amount may be increased according to the header period. In this way, by making the delay amount variable, it is possible to perform track jittering scan delay control with an appropriate delay amount according to the header period.

 As described above, according to the present embodiment, it is possible to perform the deceleration control of the light beam at the end of the track jumping run at an accurate timing, and the tracking control when the track jumping scan is completed is stable. Therefore, jumping to the target track and subsequent pull-in can be performed quickly and reliably.

 [0038] (Second Embodiment)

 FIG. 6 shows a configuration of the optical disc apparatus according to the second embodiment. This optical disc apparatus includes a header period calculation circuit 341B having a different configuration from the header period calculation circuit 341A in the optical disc apparatus according to the first embodiment. Only the differences from the first embodiment will be described below.

 The header cycle calculation circuit 341B includes a header detection circuit 3411, a counter 3413, a timer 3414, and a divider 3415. The header detection circuit 3411 is as described above. The counter 3413 counts the number of header detections by the header detection circuit 3 411 by detecting the rising edge of the signal S30. The timer 3414 measures the time required to count a predetermined number of FG signals output from the disk motor 104. Divider 3415 divides the timer value of timer 3414 by the count value of counter 3413.

 [0040] For example, when the disk motor 104 outputs six pulses as FG signals per rotation, the timer 3414 measures a time Tfg required to count six FG signals. On the other hand, the counter 3413 counts the number of header detections by the header detection circuit 3411 while the six FG signals are counted. Then, the header period is calculated by dividing the time Tfg by the count value CTh (see Fig. 7).

 [0041] (Third embodiment)

FIG. 8 shows a configuration of an optical disc device according to the third embodiment. This optical disc apparatus includes a header period calculation circuit 341C having a different configuration from the header period calculation circuits 341A and 341B in the optical disc apparatus according to the first and second embodiments. Only differences from the first and second embodiments will be described below. The header cycle calculation circuit 341C includes a zone detection circuit 3416, a timer 3414, and a divider 3415. The timer 3414 is as described above. The zone detection circuit 3416 receives an encode output EN from an encoder (not shown) included in the transfer motor 113 as a phase control signal of the optical head, and detects a zone irradiated with the light beam therefrom. If the zone can be identified, the number of sectors per track in that zone is obtained. Divider 3415 divides the timer value of timer 3414 by the number of sectors output from zone detection circuit 3414. Thereby, the header period is calculated.

 [0043] In each of the above embodiments, the optical disk 103 is not limited to DVD-RAM. Industrial applicability

The track jittering scanning control apparatus according to the present invention can perform the deceleration control of the light beam at the end of the track jittering scan at an accurate timing, and stabilize the tracking control after the track jittering scan. Therefore, it is useful for an optical disk apparatus that requires quick and reliable pull-in to a target track.

Claims

The scope of the claims  [1] An apparatus for controlling track jumping of a light beam irradiated on an optical recording medium having a plurality of sectors physically separated in one track,  A header period calculation circuit that calculates a header period from when the light beam is applied to the header area of a certain sector in the optical recording medium to the header area of the next sector;  A comparison circuit that compares the header cycle calculated by the header cycle calculation circuit with the time required for the track jittering scan;  A delay control circuit that performs a delay control of a start timing of the track jittering scan based on a comparison result of the comparison circuit.  A track jittering scanning control device.  [2] In the track jumping coaster control device according to claim 1,  The delay control circuit delays the start timing of the track jumping scan when the comparison result of the comparison circuit indicates that the header period is smaller than the time required for the track jumping scan.  A truck jumping scissor control device characterized by that. [3] In the track jumping coasting control device according to claim 2,  The delay control circuit delays the start timing of the track jittering scan by a delay amount corresponding to the header period.  A truck jumping scissor control device characterized by that. [4] In the track jumping coasting control device according to claim 3,  The delay control circuit changes the delay amount according to the header period when the header period is within a predetermined range.  A truck jumping scissor control device characterized by that. [5] In the track jumping coasting control device according to claim 2, The track jumping scanning control apparatus, wherein the delay control circuit delays the start timing of the track jumping scan by a delay amount corresponding to a zone irradiated with the light beam on the optical recording medium. [6] In the track jumping coasting control device according to claim 5,  The delay control circuit changes the delay amount according to the zone when the zone is within a predetermined range.  A truck jumping scissor control device characterized by that. [7] In the track jumping coasting control device according to claim 1,  The header period calculation circuit includes:  A header detection circuit for detecting that the light beam is applied to a header area of a sector in the optical recording medium based on reflected light of the light beam from the optical recording medium;  A track jumping stirrer control apparatus comprising: a timer that outputs a timer value and initializes a timer operation when the header detection circuit detects irradiation of the light beam to the header area. [8] In the track jumping coasting control device according to claim 1,  The header period calculation circuit includes:  A header detection circuit for detecting that the light beam is applied to a header area of a sector in the optical recording medium based on reflected light of the light beam from the optical recording medium;  A counter that counts the number of times of detection of irradiation of the light beam to the header region by the header detection circuit;  A timer for measuring the time required to count a predetermined number of FG signals output from a motor that rotationally drives the optical recording medium;  A track jumping scissor control device, comprising: a divider that divides a timer value of the timer by a count value of the counter. [9] In the track jumping coasting control device according to claim 1,  The header period calculation circuit includes:  A zone detection circuit for detecting a zone irradiated with the light beam in the optical recording medium from a transfer control signal of the optical head that irradiates the light beam; A predetermined number of FG signals output from a motor that rotates the optical recording medium are counted. A timer for measuring the time required to  A divider for dividing the timer value of the timer by the number of sectors per track in the zone detected by the zone detection circuit;  A truck jumping scissor control device characterized by that.  [10] An optical disc apparatus that reads or writes information by irradiating an optical beam onto an optical recording medium having a plurality of sectors physically separated in one track,  A track jumping carriage control unit for controlling the track jumping carriage of the light beam;  A tracking control unit that performs tracking control of the light beam in accordance with the control by the track jumping carriage control unit,  The track jumping scissor control unit is  A header period calculation circuit that calculates a header period from when the light beam is applied to the header area of a certain sector in the optical recording medium to the header area of the next sector;  A comparison circuit that compares the header period calculated by the header period calculation circuit with a predetermined value;  A delay control circuit that performs a delay control of a start timing of the track jittering scan based on a comparison result of the comparison circuit.  An optical disc device characterized by the above.  [11] A method for controlling track jittering scanning of a light beam applied to an optical recording medium having a plurality of sectors physically separated in one track,  A first step of calculating a header period from when the light beam is applied to the header area of a certain sector in the optical recording medium to when the light beam is applied to the header area of the next sector is calculated in the first step. A second step of comparing the header period and the time required for the track jittering scan; And a third step of performing delay control of the start timing of the track jittering scan based on the comparison result in the second step. A track jittering scanning control method.  [12] In the track jumping coasting control method according to claim 11,  In the third step, when the comparison result in the second step shows that the header period is smaller than the time required for the track jittering scan, the start timing of the track jumping scan is delayed.  A track jumping running control method characterized by the above. [13] In the track jumping coasting control method according to claim 12,  In the third step, the start timing of the track jittering scan is delayed by a delay amount corresponding to the header period.  A track jumping running control method characterized by the above. [14] The track jumping coasting control method according to claim 13,  In the third step, when the header period is within a predetermined range, the delay amount is changed according to the header period.  A track jittering scanning control method. [15] In the track jumping coasting control method according to claim 12,  In the third step, track start scanning control is characterized in that the start timing of the track jumping scan is delayed by a delay amount corresponding to a zone irradiated with the light beam on the optical recording medium. Method. [16] In the track jumping coasting control method according to claim 15,  In the third step, when the zone is within a predetermined range, the delay amount is changed according to the zone.  A track jumping running control method characterized by the above. [17] The track jumping coasting control method according to claim 11,  The first step includes  A fourth step of detecting, based on the reflected light of the light beam from the optical recording medium, that the light beam is applied to a header area of a sector in the optical recording medium; When irradiation of the light beam to the header area is detected in the fourth step And a fifth step of outputting the time measurement value and initializing the time measurement operation. [18] The track jumping coasting control method according to claim 11,  The first step includes  A fourth step of detecting, based on the reflected light of the light beam from the optical recording medium, that the light beam is applied to a header area of a sector in the optical recording medium;  A fifth step of counting the number of detections of irradiation of the light beam to the header area in the fourth step;  A sixth step of measuring the time required to count a predetermined number of FG signals output from a motor that rotationally drives the optical recording medium;  And a seventh step of dividing the time measurement value in the sixth step by the count value in the fifth step.  A track jittering scanning control method. [19] In the track jumping coasting control method according to claim 11,  The header period calculation circuit includes:  A fourth step of detecting a zone of the optical recording medium irradiated with the light beam from a transfer control signal of the optical head that irradiates the light beam;  A fifth step of measuring the time required to count a predetermined number of FG signals output from a motor that rotationally drives the optical recording medium;  A sixth step of dividing the time measurement value in the fifth step by the number of sectors per track in the zone detected in the step 4  A track jumping running control method characterized by the above.