WO2007052525A1 - Dispositif d’entraînement d’une lentille d’objectif et procédé d’entraînement - Google Patents

Dispositif d’entraînement d’une lentille d’objectif et procédé d’entraînement Download PDF

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Publication number
WO2007052525A1
WO2007052525A1 PCT/JP2006/321354 JP2006321354W WO2007052525A1 WO 2007052525 A1 WO2007052525 A1 WO 2007052525A1 JP 2006321354 W JP2006321354 W JP 2006321354W WO 2007052525 A1 WO2007052525 A1 WO 2007052525A1
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WIPO (PCT)
Prior art keywords
objective lens
focal point
observed
optical disc
driving
Prior art date
Application number
PCT/JP2006/321354
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English (en)
Japanese (ja)
Inventor
Yoshimichi Nishio
Takaaki Ujiie
Yoshihiro Hashizuka
Original Assignee
Pioneer Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pioneer Corporation filed Critical Pioneer Corporation
Priority to JP2007542643A priority Critical patent/JP4660555B2/ja
Publication of WO2007052525A1 publication Critical patent/WO2007052525A1/fr

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Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
    • G11B7/085—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam into, or out of, its operative position or across tracks, otherwise than during the transducing operation, e.g. for adjustment or preliminary positioning or track change or selection
    • G11B7/08505—Methods for track change, selection or preliminary positioning by moving the head
    • G11B7/08511—Methods for track change, selection or preliminary positioning by moving the head with focus pull-in only
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B2007/0003—Recording, reproducing or erasing systems characterised by the structure or type of the carrier
    • G11B2007/0009—Recording, reproducing or erasing systems characterised by the structure or type of the carrier for carriers having data stored in three dimensions, e.g. volume storage
    • G11B2007/0013—Recording, reproducing or erasing systems characterised by the structure or type of the carrier for carriers having data stored in three dimensions, e.g. volume storage for carriers having multiple discrete layers

Definitions

  • the present invention relates to a driving apparatus and a driving method for driving an objective lens used in an optical disk reproducing apparatus or the like.
  • Optical disc playback devices and the like require an operation to focus the objective lens on the signal surface of the optical disc (focus pull-in) before playback of the optical disc. Changes in the operating environment of the playback device, warping of optical discs and signals In consideration of changes in the relative speed between the optical disc and the objective lens due to surface deflection caused by surface distortion, etc., the drive speed of the objective lens is fixed at a constant speed so that the focus bow I can be inserted even under the worst conditions. And then.
  • Patent Document 1 Japanese Patent Application Laid-Open No. 2004-14091
  • the amount of surface blur is It is an object of the present invention to provide an objective lens driving device and a driving method capable of shortening the force pull-in time when there is little blurring by setting the driving speed of the objective lens according to the above.
  • the invention according to claim 1 is directed to a light source, an objective lens for irradiating light from the light source with focusing on the optical disc, and the objective lens to the optical disc.
  • an objective lens driving device comprising a driving means for moving in a substantially vertical direction
  • the observation means is caused to observe the focal point on the optical disc by moving the objective lens to a certain range by the driving means.
  • a control means for changing the speed at which the driving means moves the objective lens in order to perform the force pull-in according to the result! / Speak.
  • the invention according to claim 9 is directed to an objective lens driving method for moving an objective lens for irradiating light of light source power while focusing on the optical disc in a substantially vertical direction with respect to the optical disc.
  • the objective lens is moved by a certain amount, the focal point on the optical disc is observed, and the speed at which the objective lens is driven is changed according to the observation result in order to perform focus pull-in.
  • FIG. 2 is an explanatory diagram of a light receiver of the optical pickup in the optical disc player shown in FIG.
  • FIG. 3 is an explanatory diagram of a waveform of a focus error signal.
  • FIG. 4 is a flowchart showing an objective lens driving speed determining operation in the first embodiment of the optical disc player shown in FIG. 1.
  • FIG. 4 is a flowchart showing an objective lens driving speed determining operation in the first embodiment of the optical disc player shown in FIG. 1.
  • FIG. 5 (a), (b) and (c) are explanatory diagrams of the relationship between the objective lens when the objective lens is driven, the focal point of the light emitted from the objective lens, and the signal surface of the optical disc.
  • FIG. 6 is a flowchart showing an objective lens drive speed determination operation in the second embodiment of the optical disc player shown in FIG. 1.
  • FIGS. 7A and 7B are explanatory diagrams of a method for determining the driving speed of the objective lens in the second embodiment.
  • FIG. 8 is a flowchart showing an objective lens driving speed determination operation in the third embodiment of the optical disk player shown in FIG. 1.
  • FIG. 8 is a flowchart showing an objective lens driving speed determination operation in the third embodiment of the optical disk player shown in FIG. 1.
  • FIG. 9 is an explanatory diagram of a method for determining a driving speed and a driving range of an objective lens according to a third embodiment.
  • the control means increases the speed at which the objective lens is driven when the number of times of crossing the focal point on the optical disk is less than a predetermined value.
  • the speed which drives an objective lens may be made slow. That is, when the surface blur is large, the number of times of crossing the focal point is large. When the surface blur is small, the number of times of crossing the focal point is small. Therefore, the driving speed of the objective lens can be changed depending on the amount of surface blur.
  • control means causes the position acquisition means to acquire the position of the objective lens when the observation means observes the focal point on the optical disc, and first adjusts the objective lens when the objective lens is moved within a certain range.
  • the driving range for focusing the objective lens may be changed. By doing so, the range in which the objective lens is driven can be limited, so that the focus pull-in time can be shortened.
  • control unit divides the fixed range in which the objective lens is moved into a plurality of ranges, and moves the driving range of the objective lens at the time of focus pull-in according to the range where the focal point exists in the plurality of ranges. You may do it. By doing this, the focus pull-in time can be shortened because the range where the in-focus point exists can be limited during focus pull-in. It can be done.
  • the control unit performs a plurality of the above observations observed within the second predetermined time.
  • the focal point may be counted as one.
  • the observation unit may set a position where any one or more of the focus error signal, the RF signal, and the return light total signal are observed as a focal point.
  • These signals are signals that are generated when the amount of reflected light from the optical disc exceeds a predetermined amount, so that it is easy to observe the focal point.
  • the position of the objective lens when the focal point on the optical disk is observed is acquired, and the focal point is first observed when the objective lens is moved within a certain range, and finally the focal point is determined.
  • the driving range for focusing the objective lens may be changed according to the observed position. By doing so, the range in which the objective lens is driven can be limited, so that the focus pull-in time can be shortened.
  • optical disc player 1 as an objective lens driving device that is effective in the first embodiment of the present invention will be described with reference to Figs.
  • the optical disc player 1 has multiple optical discs such as a DVD (Digital Versatile Disc), CD (Compact Disc), and BD (Blu-ray Disc), and multiple DVDs. It is a device that can reproduce multi-layer discs such as laminated optical discs and optical discs with DVD layers and BD layers.
  • disc motor 2, optical pickup 3, RF amplifier 4, servo signal A processing unit 5, a driver 6, an audio Z video signal processing unit 7, a DA converter 8, an audio signal Z video signal output terminal 9, and a microcomputer 10 are provided.
  • the disc motor 2 is a motor for rotating the optical disc 11 set in the optical disc player 1, and includes a spindle motor or the like.
  • the optical pickup 3 includes a laser diode (not shown) that generates light to be irradiated on the optical disc 11, an objective lens for irradiating the optical disc 11 with laser light from the laser diode, and a servo signal processing unit 5 And a receiver 30 that receives the reflected light reflected from the optical disk 11, and a focus error signal as a focal point is output from the output of the receiver 30. Generate and output.
  • the light receiver 30 includes a four-divided light receiver 31.
  • the quadrant light receiver 31 includes light receiving surfaces 31a, 31b, 31c and 31d.
  • the focus error signal is obtained by adding the outputs of the light receiving surfaces 31b and 31d at the other diagonal position from the sum of the outputs of the light receiving surfaces 3la and 31c at one of the diagonal positions in the quadrant light receiver 31. 3 is subtracted (ie, (31a + 31c)-(31b + 31d)) and the waveform shown in FIG. 3 is obtained, and Vfe in FIG. 3 is the focus error signal level as the intensity of reflected light at the focal point.
  • the RF amplifier 4 amplifies the signal output from the optical pickup 3 to a predetermined value and outputs it to the servo signal processing unit 5.
  • Servo signal processing unit 5 as drive means and observation means is used to observe the presence and level of a focus error signal, which is a signal input from the reflected light from optical disk 11 and input to RF amplifier 4 power,
  • the objective lens of the pickup 3 is driven to control focus and tracking so that the information recorded on the optical disk 11 can be read accurately.
  • a signal including information such as music and video recorded on the optical disc 11 is converted to analog Z digital and output to the audio Z video signal processing unit 7.
  • the driver 6 amplifies the signal input from the servo signal processing unit 5 and outputs the amplified signal to the disk motor 2 and the optical pickup 3.
  • the audio Z video signal processing unit 7 demodulates the signal input from the servo signal processing unit 5 into an audio or video signal, performs error correction, and outputs the signal to the DA converter 8.
  • a microcomputer 10 serving as a control means and a position acquisition means has a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory), and the optical disk 11 is inserted and ejected. Controls the entire optical disc player 1 in each operation such as recording Z playback and stop, and determines the objective lens drive speed and drive range from the focus error signal observed by the servo signal processing unit 5.
  • CPU Central Processing Unit
  • RAM Random Access Memory
  • ROM Read Only Memory
  • the flowchart shown in FIG. 4 is realized by the CPU of the microcomputer 10 executing the control program stored in the ROM of the microcomputer 10.
  • FIG. 5 shows the relationship between the objective lens, the focal point of the light emitted from the objective lens, and the signal surface of the optical disc when the objective lens is moved in a direction in which the positional force far from the optical disc is brought closer to the optical disc.
  • Fig. 5 (a) shows the case where the optical disc surface is shaken, that is, when the optical disc rotates, the signal plane has a large fluctuation in the focus direction.
  • the focal point of the objective lens is separated from the objective lens by a distance h0. If the objective lens moves, the focal point moves while maintaining the distance h0. As shown in Fig.
  • step S 101 the servo signal processing unit 5 is instructed to drive the objective lens in the vertical direction with respect to the optical disc 11 while continuing to irradiate the laser light from the laser diode of the optical pickup 3. Proceed to step S102.
  • the servo signal processing unit 5 outputs, via the driver 6, a signal that drives the objective lens away from the optical pickup 3, for example, in the direction toward the optical disc 11 and close to the positional force optical disc 11.
  • the fixed range is a range in which the objective lens is driven while continuing to irradiate laser light from a laser diode sufficient to determine the amount of surface blurring of the optical disc 11 in step S108 described later. For example, the bottom dead center To top dead center.
  • step S102 the servo signal processing unit 5 observes the focus error signal output from the optical pickup 3 when the signal surface of the optical disc 11 crosses the focal point.
  • the observed focus error signal level as the intensity of the reflected light is output to the microcomputer 10.
  • the focus error signal level observed from the servo signal processing unit 5 and input to the microcomputer 10 and the observation time of the focus error signal observed from the first time on the basis of the focus error signal first observed are used. measure.
  • the observation time of the focus error signal and the level at that time are stored in RAM in the microcomputer 10. Further, the result of counting the total number of observed focus error signals as a result of moving the objective lens is also stored in the RAM in the microcomputer 10, and the process proceeds to step S103.
  • step S103 it is determined whether or not a plurality of focus error signals are observed within a second predetermined time set in advance and stored in the ROM of the microcomputer 10 as a result of moving the objective lens. To do. If a plurality of observations are made within the second predetermined time (in the case of YES), the process proceeds to step S107, and if not (in the case of NO), the process proceeds to step S104.
  • the focal point of one signal surface (focus error signal) and the focal point of the other signal surface four This is a time interval sufficient for observing a cascading error signal).
  • Fig. 5 (c) shows the case where there are two signal surfaces. In the case of two layers, there are two waveforms representing the signal plane that is blurred as shown in Fig. 5 (c). In Fig. 5 (c), the signal plane crosses the focal point in the first and second layers, and there are six locations. Will be misjudged. Therefore, the accurate amount of surface blur can be determined by counting the number of times one signal surface crosses the focal point.
  • the second predetermined time is, for example, twice the time required to move the objective lens by the distance between the two most distant layers among the signal surfaces stacked on the optical disk 11.
  • the distance between each layer is very small compared to the surface blur width of the optical disk. Such a judgment is effective for counting the number of times the signal surface of the optical disk crosses the focal point by moving the optical disk.
  • step S104 when the focus error signal level first observed is within a range of levels that can be taken in the case of a predetermined type of optical disc stored in the ROM of the microcomputer 10, for example, a DVD. Then, it is determined whether or not all the focus error signal levels observed after the second are within the range of levels that can be taken by the DVD that is a predetermined range stored in the ROM of the microcomputer 10. If all observed focus error signal levels are within the range of levels that can be taken by the DVD (in the case of YES), the process proceeds to step S105, and if a level outside the predetermined range exists (in the case of NO), the step is performed. Proceed to S106. That is, it is determined whether or not the focus error signal level is within a predetermined range.
  • the predetermined range means that when a focus error signal as the focal point is observed from multiple layers on an optical disc 11 in which multiple media (for example, BD and DVD) are stacked, the number of actual surface blurs is counted more than the actual range. Therefore, it refers to the range of levels that the media can take in order to count only the focus error signals from a particular media layer.
  • the position of the recording surface (depth from the optical disk surface) on the optical disc is determined for each type of media, different types of media are stacked. In some cases, the distance between layers may be increased depending on the combination of media.
  • the range that the focus error signal level can take varies depending on the type of the medium of the optical disk. Therefore, it is effective to use the focus error signal level in order to count only the focus error signal of a specific medium layer force on an optical disc in which different types of media are stacked.
  • step S105 the total number of observations of the focus error signal counted in step S102 is read from the RAM, and the process proceeds to step S108.
  • step S106 an optical disc on which different types of media are stacked (for example, BD and D
  • step S108 only the focus error signal within a predetermined range is counted.
  • step S107 it is determined that the same type of media such as DVDs is stacked, and a plurality of focus error signals observed within the second predetermined time are counted as one time. Then go to step S108. For example, if the second predetermined time is t in Fig. 5 (c), the time from the point j where the signal plane of the first layer crosses the focal point to the point where the signal plane of the second layer crosses the focal point is 5 Because it is within t as shown in (c); ⁇ is not counted. Similarly, other points where the signal plane of the second layer crosses the focal point in Fig. 5 (c) are not counted because they are within t from the point where the signal plane of the first layer crosses the focal point.
  • step S108 it is determined whether or not the counted number of focus error signals is equal to or greater than a predetermined value that is preset and stored in the ROM of the microcomputer 10. If YES, the process proceeds to step S110. If less than the predetermined value (NO), the process proceeds to step S109.
  • the predetermined value is a value with which the amount of surface blur can be determined.
  • step S109 the number of times the focus error signal has been observed is small, that is, the number of times that the signal surface of the optical disk has crossed the focal point is less than the predetermined value, so it is determined that the surface blur is small! / Then, the servo signal processing unit 5 is instructed to drive the object lens at a speed (high speed) that is faster than the speed at the predetermined worst condition.
  • step SI10 if the focus error signal is observed many times, that is, if the signal surface of the optical disc crosses the focal point is more than a predetermined value, The servo signal processing unit 5 is instructed to drive the objective lens at a slow V and speed (low speed) so that the focus can be pulled in even under the worst condition determined in advance.
  • the number of times of crossing the signal surface of the optical disk and the focal point is counted, and if the result is equal to or greater than a predetermined value set in advance, it is determined that the surface blur is large and the objective lens is moved at a low speed. Since the objective lens is driven at high speed because it is judged that the surface blur is small if it is less than the predetermined value, the drive speed of the objective lens can be changed according to the amount of surface blur. When the amount is small, the focus pull-in time is shortened.
  • the configuration is the same as that of the first embodiment. Instead of counting the number of times that the signal surface of the optical disk crosses the focal point in determining the magnitude of the amount of shake on the surface of the optical disk, The difference is that the time span is measured from the time the surface first crosses the focal point to the last time it crosses the focal point. Therefore, a part of the control program of the microcomputer 10 has been changed.
  • FIG. 6 shows a flow of operations for determining the driving speed of the objective lens in the present invention.
  • FIG. 7 shows the same distance h0 to the focal point and the amount of surface blur as in Figure 5.
  • Fig. 7 (a) shows the case where the optical disc surface shake is large! /.
  • Fig. 7 (a) when the objective lens is moved in a certain range up to h2 in the focus direction, the time when the signal surface of the optical disc first crosses the focal point The time when the tl force also crosses last There is a time span of T1 by t2.
  • Figure 7 (b) shows the case where the surface shake is small! /.
  • Time t3 force when the signal surface of the optical disc first crosses the focal point for the first time t3 force time T4 is the time width by t4 when it last crosses. That is, as shown in FIG. 7, when the objective lens is moved, the time width that the signal surface of the optical disc crosses the focal point is smaller when the surface blur is small than when the surface blur is large (T1> T2). Therefore, as in the first embodiment, the focus error signal is observed, It is possible to distinguish the magnitude of the surface shake by measuring the observation result force time width.
  • the servo signal processing unit is configured to drive the objective lens in a vertical direction with respect to the optical disc 11 while continuing to irradiate laser light from the laser diode of the optical pickup 3. Instruct 5 and go to Step S202.
  • the servo signal processing unit 5 outputs, via the driver 6, a signal that drives the objective lens away from the optical pickup 3, for example, away from the optical disk 11 and closer to the positional force optical disk 11.
  • the fixed range is a range in which the objective lens is driven while continuing to irradiate laser light from a laser diode sufficient to determine the amount of surface blur of the optical disc 11 in step S206, which will be described later. For example, the bottom dead center To top dead center.
  • step S202 the servo signal processing unit 5 observes the focus error signal output from the optical pickup 3 when the signal surface of the optical disc 11 crosses the focal point.
  • the observed focus error signal level as the intensity of the reflected light is output to the microcomputer 10.
  • the microphone computer 10 measures the observed focus error signal level and the time width at which the focus error signal is first observed and the force error signal is finally observed, and stores it in the RAM. Then, the process proceeds to step S203.
  • the focus error signal level first observed is a range of levels that can be taken in the case of a predetermined type of optical disc stored in the ROM of the microcomputer 10, for example, a DVD. If it is determined that all the focus error signal levels observed after the second are within the range of levels that can be taken by the DVD, which is a predetermined range stored in the ROM of the microcomputer 10. If all the observed focus error signal levels are within the range of levels that can be taken by the DVD (in the case of YES), the process proceeds to step S204. If a level outside the predetermined range exists (in the case of NO), the process proceeds to step S205. Proceed to That is, it is determined whether or not the focus error signal level is within a predetermined range.
  • the predetermined range is the same as in step S104, when the focus error signal as the in-focus point is observed from multiple layers on the optical disc 11 on which a plurality of media (for example, BD and DVD) are stacked. More than counted Therefore, in order to count only the focus error signal from a specific media layer, the range of levels that the media can take! Uh.
  • step S204,! / Using the time width measured in step S202 as it is, the process proceeds to step S206.
  • step S205 it is determined that the disc is an optical disc (eg, BD and DVD) on which different types of media are stacked, and the level is within a predetermined range compared to the focus error signal first observed. Remeasure the time width of the difference signal only, and go to Step S206. That is, only the focus error signal within a predetermined range is counted.
  • an optical disc eg, BD and DVD
  • step S206 it is determined whether or not the time width of the measured focus error signal is equal to or longer than a first predetermined time set in advance and stored in the ROM of the microcomputer 10. If it is longer than the predetermined time (in the case of YES), the process proceeds to step S208. If it is less than the predetermined time (in the case of NO), the process proceeds to step S207.
  • the first predetermined time is a time width in which the amount of surface shake can be distinguished.
  • step S207 the time width over which the focus error signal is observed is shorter than the first predetermined time, that is, the time width in which the signal surface of the optical disk crosses the focal point is short, so it is determined that the surface blur is small. Then, the servo signal processing unit 5 is instructed to drive the objective lens at a speed (high speed) faster than the speed at the predetermined worst condition.
  • step S208 the time width over which the focus error signal is observed is longer than the first predetermined time, that is, the time width in which the signal surface of the optical disk crosses the focal point is long, so it is determined that the surface blur is large. Then, the servo signal processing unit 5 is instructed to drive the objective lens at a slow speed (low speed) at which the focus can be pulled in even in the worst case condition.
  • the time width over which the signal surface of the optical disk crosses the focal point is measured, and if the result is equal to or longer than the first predetermined time set in advance, it is determined that the surface blur is large and the speed is low.
  • the driving speed of the objective lens is changed according to the amount of the surface blur. If the surface blur is small, the focus pull-in time is shortened.
  • step S301 the servo signal processing unit 5 is instructed to drive the objective lens in a vertical range with respect to the optical disc 11 while continuing to irradiate laser light from the laser diode of the optical pickup 3 (step S302). Proceed to The servo signal processing unit 5 outputs, via the driver 6, a signal that drives the objective lens away from the optical pickup 3, for example, away from the optical disk 11 and closer to the positional force optical disk 11.
  • the fixed range is a range in which the objective lens is driven while irradiating laser light from the optical pickup 3 sufficient to determine the amount of surface blur of the optical disk 11 in step S306 described later. Desirably, from point to top dead center.
  • step S302 as the observation means and the position acquisition means, the servo signal processing unit 5 converts the focus error signal output from the optical pickup 3 when the signal surface of the optical disk 11 crosses the focal point.
  • the observed focus error signal level is output to the microcomputer 10.
  • the focus error signal level is inputted from the servo signal processing unit 5, the area number as the observation position and the level as the intensity of the reflected light are combined and stored in the RAM.
  • the focus error is Area force where one signal was observed
  • step S303 proceed to step S303.
  • step S303 when the first observed focus error signal level is within a range of levels that can be taken in the case of a predetermined type of optical disk, such as a DVD, stored in advance in the ROM of the microcomputer Determines whether all the focus error signal levels observed after the second are within the range of levels that can be taken by the DVD, which is a predetermined range stored in the ROM of the microcomputer 10. If all of the observed focus error signal levels are within the range of levels that the DVD can take (YES), go to step S305. If there is a level outside the specified range (NO), go to step S304. move on. That is, it is determined whether or not the focus error signal level is within a predetermined range.
  • a predetermined type of optical disk such as a DVD
  • the predetermined range is the same as in steps S104 and S203, when the focus error signal as the focal point is observed from multiple layers on the optical disc 11 on which a plurality of media (for example, BD and DVD) are stacked. Because it counts more than the amount, the range of levels that the media can take to count only the focus error signals from a particular media layer! Uh.
  • step S304 the number of areas counted in step S302 is read from the RAM, and the process proceeds to step S306.
  • step S305 it is determined that the disc is an optical disc on which different types of media are stacked (for example, BD and DVD), and all levels and areas in which the RAM force is also observed are read out and observed first.
  • the number of areas in which a signal with a level difference within a predetermined range is observed compared with the focus error signal is counted, and the process proceeds to step S306. That is, only the focus error signal within a predetermined range is counted.
  • step S306 it is determined whether or not the counted number of areas is greater than or equal to a predetermined value (corresponding to the second predetermined time described above) preset and stored in the ROM of the microcomputer 10. If it is equal to or greater than the predetermined value (in the case of YES), the process proceeds to step S308. If it is less than the predetermined value (in the case of NO), the process proceeds to step S307.
  • a predetermined value corresponding to the second predetermined time described above
  • step S307 the area in which the focus error signal is observed is small, that is, the time width during which the signal surface of the optical disk crosses the focal point is short, so that the surface blur is small.
  • the servo signal processing unit 5 is instructed to drive the objective lens at a speed (high speed) higher than the speed under the worst condition set in advance, and the process proceeds to step S309.
  • step S308 it is determined that there are many areas where the focus error signal is observed, that is, the time of the optical disc signal surface crossing the focal point is long, so that the surface blur is large.
  • the servo signal processing unit 5 is instructed to drive the objective lens at a slow speed (low speed) at which the focus can be drawn, and the process proceeds to step S309.
  • step S309 the area number obtained by subtracting 1 from the smallest area number where the focus error signal was observed (the position where the focus error signal was first observed) is set as the objective lens drive lower limit value. Then go to step S310.
  • step S310 an area number obtained by adding 1 from the largest area number where the focus error signal was observed (the position where the focus error signal was observed last) is set as the objective lens drive upper limit value.
  • the servo signal processing unit 5 is instructed to set the drive range from the set objective lens drive lower limit value to the objective lens drive upper limit value.
  • the driving range is from 4 to 7. That is, the drive range of the objective lens in the focus pull-in operation is changed according to the area where the focus error signal was first observed and the area where the focus error signal was last observed.
  • the objective lens is moved once, the moving time is divided into a plurality of areas, the detection of the area where the signal surface of the optical disc crosses the focal point and the number of areas are counted, and the counted area If the number is equal to or greater than the preset value, the surface blur is judged to be large! /, And the objective lens is driven at a low speed, and if it is less than the predetermined value, the surface blur is judged to be small! Drive.
  • the crossed area force drive range can be detected and set, so the drive speed and drive range of the objective lens can be changed according to the amount of surface shake. It is even shorter than just doing it.
  • the time axis is divided into a plurality of areas in the present embodiment
  • the focus direction may be divided into a plurality of areas.
  • the amount of surface blur was determined by counting the number of areas divided by the time axis.
  • the method of the second embodiment may be applied as it is.
  • the method of dividing the area into the areas to determine the driving range is not changed, and the method of counting the number of crossings in the first embodiment may be combined with the determination of the driving speed.
  • the driving range is a range with a margin for each of the upper and lower limits than the range in which the focus error signal is observed.
  • the driving range is not limited to this, and the range in which the focus error signal is observed is driven. It may be a range or allow more than 2 areas.
  • the drive range of only either the upper limit or the lower limit may be limited.
  • the focus error signal is used as the signal observed when the focal point crosses the signal surface of the optical disc.
  • the return light sum signal and the RF signal are used. Any signal that can be generated by the optical pickup 3 and observed by the servo signal processor 5 when the focal point crosses the signal surface of the optical disk, etc. can be observed. It can be used to judge the amount of quantity.
  • the driving speed is set to two stages of low speed and high speed.
  • the driving speed may be three stages or more instead of two stages. If there are three or more stages, set a predetermined value or first predetermined time in the ROM of the microcomputer 10 according to the number of stages.
  • the signal first detected in determining the level difference of the focus error signal is used as a reference.
  • the present invention is not limited to this.
  • the signal having the highest or lowest signal level is used as a reference.
  • the signal power may be counted or measured within a predetermined level difference.
  • the DVD, CD, and BD can be played back.
  • the present invention is not limited to this, and can be applied to other types of optical disks such as HD-DVD.
  • the following objective lens driving device and driving method can be obtained.
  • the focus pull-in time can be shortened.
  • the focus pull-in is performed at a speed according to the amount of the surface blur. If there is little surface blur, the focus pull-in time can be shortened.

Landscapes

  • Moving Of The Head For Recording And Reproducing By Optical Means (AREA)
  • Optical Recording Or Reproduction (AREA)

Abstract

La présente invention vise à modifier la vitesse d’entraînement d’une lentille d’objectif en fonction de l’importance des oscillations d’un disque optique dans un dispositif d’entraînement d’une lentille d’objectif disposé dans un dispositif de disque optique et à réduire le temps de mise au point lorsque les oscillations sont faibles. La lentille d’objectif de l’invention dans un enregistreur optique (3) est déplacée à l’intérieur d’une certaine gamme à partir d'une unité de traitement (5) de signal asservi. Un signal d’erreur de mise au point généré lorsque la lentille d’objectif traverse le point focal d’un disque optique (11) est observé par l’unité de traitement (5) de signal asservi. En fonction du résultat observé, un micro-ordinateur (10) modifie la vitesse de déplacement de la lentille d’objectif afin d’effectuer la mise au point.
PCT/JP2006/321354 2005-11-07 2006-10-26 Dispositif d’entraînement d’une lentille d’objectif et procédé d’entraînement WO2007052525A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2007542643A JP4660555B2 (ja) 2005-11-07 2006-10-26 対物レンズ駆動装置および駆動方法

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2005-322126 2005-11-07
JP2005322126 2005-11-07

Publications (1)

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WO2007052525A1 true WO2007052525A1 (fr) 2007-05-10

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PCT/JP2006/321354 WO2007052525A1 (fr) 2005-11-07 2006-10-26 Dispositif d’entraînement d’une lentille d’objectif et procédé d’entraînement

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JP (1) JP4660555B2 (fr)
WO (1) WO2007052525A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014097394A1 (fr) * 2012-12-18 2014-06-26 三菱電機株式会社 Dispositif de reproduction de disques et procédé de tirage d'asservissement de mise au point

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001184670A (ja) * 1999-12-24 2001-07-06 Hitachi Ltd 光ディスク装置
JP2004014091A (ja) * 2002-06-11 2004-01-15 Matsushita Electric Ind Co Ltd フォーカス引き込み制御方法

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001184670A (ja) * 1999-12-24 2001-07-06 Hitachi Ltd 光ディスク装置
JP2004014091A (ja) * 2002-06-11 2004-01-15 Matsushita Electric Ind Co Ltd フォーカス引き込み制御方法

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014097394A1 (fr) * 2012-12-18 2014-06-26 三菱電機株式会社 Dispositif de reproduction de disques et procédé de tirage d'asservissement de mise au point

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JP4660555B2 (ja) 2011-03-30
JPWO2007052525A1 (ja) 2009-04-30

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