JP5397395B2 - Optical disk device - Google Patents

Description

  The present invention relates to an optical disc apparatus that performs reproduction or recording of an optical disc, and more particularly to an optical disc apparatus that can suppress servo detachment during seek processing.

  In recent years, optical discs such as CD (Compact Disc) and DVD (Digital Versatile Disc) have become widespread and are generally used. As an apparatus for reading and recording / reproducing information recorded on an optical disk, such as audio information and image information, there is an optical disk apparatus. As a widely known optical disk device, for example, a CD player, a DVD player, a CD-ROM drive connected to a personal computer, and the like can be cited.

  The optical disc apparatus includes an optical pickup for reading information by irradiating the optical disc with a light beam. The optical pickup irradiates a light beam onto an information recording surface of an optical disk fixed on a turntable and rotating.

  The reflected light from the information recording surface is received by a photodetector such as a photodiode provided in the optical pickup. Then, the light is converted into an electrical signal by the photodetector, and information recorded on the optical disk is output based on the obtained electrical signal.

  In the mounting process for making the optical disc playable, it is necessary to first acquire the focus pull-in position by focus search, focus pull-in, and turn on the focus servo. In order to achieve this, an optical pickup is provided with an actuator for driving the objective lens in the optical axis direction and a focus servo for controlling the actuator.

  In relation to the above, Japanese Patent Application Laid-Open No. H10-228707 detects the amount of received light deviation in the disc radial direction of the optical pickup photodetector during the search operation by the optical pickup, and moves the objective lens of the optical pickup in a direction to cancel the deviation amount. Thus, an optical disc reproducing apparatus that alleviates detracking is disclosed.

  Patent Document 2 discloses an intermediate balance adjustment between a focus error signal balance adjustment value when the RF signal level reaches a maximum value and a focus error signal balance adjustment value when jitter reaches a minimum value. There has been disclosed an optical disc reproducing apparatus that improves the balance adjustment of a focus error signal and improves the accuracy of the focus servo by adjusting the focus balance according to the value.

  Patent Document 3 discloses an automatic adjustment method for optimizing a servo and an equalizer so that a pickup head with poor lens shift characteristics can be used effectively by grasping the lens shift characteristics of an optical pickup during adjustment. Yes.

JP 2008-123636 A JP 2006-134447 A JP 2002-92914 A

  In any of the optical disk apparatuses disclosed in Patent Documents 1 to 3, the balance adjustment (hereinafter referred to as “S-shaped balance adjustment”) that minimizes the focus error balance of the FE signal is first performed during the optical disk mounting process. ) Adjusts the optical pickup to a position where servo stability is good. Thereafter, the optical pickup is adjusted to a position with good reproduction performance by balance adjustment (hereinafter referred to as “focus balance adjustment”) that maximizes the level of the RF signal. Thereby, the balance of the FE signal is adjusted appropriately.

  However, in an optical pickup having a large defocus, the difference between the S-shaped balance adjustment value and the focus balance adjustment value becomes large. For this reason, when the seek process is performed using the focus balance adjustment value, there is a problem in that the servo is frequently lost during the seek and the reproduction cannot be performed.

  An object of the present invention is an optical disc apparatus that performs S-shaped balance adjustment and focus balance adjustment during mounting processing, and performs stable seek processing even when the difference between the S-shaped balance adjustment value and the focus balance adjustment value is large. An object of the present invention is to provide an optical disc device that can be used.

  In order to achieve the above object, an optical disc apparatus according to the present invention includes a light source that irradiates a recording surface of an optical disc with a light beam, an optical pickup that includes a photodetector that photoelectrically converts reflected light from the recording surface, and the photoelectric pickup. A signal generation unit that generates a total reflection signal indicating the amount of reflected light and a focus error signal from the electrical signal obtained by the conversion, and controls the optical pickup based on the total reflection signal and the focus error signal. In an optical disc apparatus including a servo control unit for performing, a first adjustment value that is an adjustment value for adjusting the optical pickup so that an error balance of the focus error signal is minimized, and the total reflection signal is maximized. A difference value with a second adjustment value that is an adjustment value for adjusting the optical pickup is calculated, and the difference value is determined in advance. It is determined whether or not the threshold value is exceeded, and when the difference value exceeds the threshold value, the servo control unit is configured to adjust the optical pickup using the first adjustment value in a predetermined type of processing. The main control part to control is provided.

  According to this configuration, the optical disc apparatus of the present invention includes an optical pickup including a light source that irradiates a recording surface of an optical disc with a light beam and a photodetector that photoelectrically converts reflected light from the recording surface. In addition, a signal generation unit that generates a total reflection signal indicating the amount of reflected light and a focus error signal from an electrical signal obtained by photoelectric conversion is provided. In addition, a servo control unit that controls the optical pickup based on the total reflection signal and the focus error signal is provided. Furthermore, a first adjustment value that is an adjustment value for adjusting the optical pickup so that the error balance of the focus error signal is minimized, and an adjustment value that is an adjustment value for adjusting the optical pickup so that the total reflection signal is maximized. A main control unit that calculates a difference value from the two adjustment values is provided. The main control unit determines whether or not the difference value exceeds a predetermined threshold value. If the predetermined value is exceeded, the servo control unit is controlled to adjust the optical pickup using the first adjustment value.

  In order to achieve the above object, the optical disc apparatus of the present invention includes a recording unit for recording information, and the main control unit is configured to execute the first adjustment value and the first adjustment value during the mounting process of the optical disc mounted on the optical disc device. The second adjustment value is acquired and recorded in the recording unit, the difference value is calculated from the first adjustment value and the second adjustment value, and when the difference value exceeds a predetermined threshold, seek is performed. The servo control unit is controlled to adjust the optical pickup using the first adjustment value at the time of processing.

  According to this configuration, the optical disc apparatus includes the recording unit that records information. The main control unit acquires and records the first adjustment value and the second adjustment value in the recording unit during the optical disc mounting process. Further, the main control unit controls the servo control unit to adjust the optical pickup using the first adjustment value during the seek process when the difference value exceeds a predetermined threshold value.

  Further, in order to achieve the above object, the main control unit provided in the optical disc apparatus of the present invention, when the adjustment of the optical pickup at the time of seek processing is performed by the first adjustment value, and when the seek processing is completed, The servo control unit is controlled so that the optical pickup is adjusted by the second adjustment value after the seek process.

  According to this configuration, the main control unit adjusts the optical pickup with the first adjustment value during the seek process, and adjusts the optical pickup after the seek process with the second adjustment value when the seek process is completed. Control the servo controller to do so.

  In order to achieve the above object, the main controller provided in the optical disc apparatus of the present invention uses the second adjustment value during the seek process when the difference value does not exceed a predetermined threshold value. The servo control unit is controlled to adjust the pickup.

  According to this configuration, the main control unit controls the servo control unit to adjust the optical pickup using the second adjustment value during the seek process when the difference value does not exceed the predetermined threshold value.

  According to the present invention, when the difference between the first adjustment value based on the focus error signal and the adjustment value based on the total reflection signal is large, the seek process is performed using the first adjustment value. This increases the servo stability during seeking. Therefore, even when the defocus of the optical pickup is large, it is possible to suppress the servo deviation at the time of seek.

1 is a block diagram showing a configuration of an optical disc device according to an embodiment of the present invention. It is a schematic diagram which shows the optical system of the optical pick-up concerning one Embodiment of this invention. It is a flowchart which shows the processing flow of the mount process which concerns on one Embodiment of this invention. It is a flowchart which shows the process flow of the seek process which concerns on one Embodiment of this invention. It is a graph which shows the relationship between a focus error signal and a total reflection signal.

Embodiments of the present invention will be described below with reference to the drawings. In addition, embodiment shown here is an example and this invention is not limited to embodiment shown here.
<1. Internal configuration>

  FIG. 1 is a configuration diagram showing a disc player 100 (= optical disc apparatus) according to an embodiment of the present invention. The disc player 100 includes an optical pickup 1, a signal generation circuit 21 (= signal generation unit), a DSP (Digital Signal Processor) 31 (= servo control unit), a reproduction processing circuit 32, an output circuit 33, and a system controller 41 (= main control). A driver 42, a display unit 43, an operation unit 44, a recording unit 45, a feed motor 51, and a spindle motor 52.

  The optical pickup 1 irradiates the optical disc 2 with a light beam and reads various information such as audio information and image information recorded on the optical disc 2. The optical pickup 1 is provided with a CD light beam, a DVD light beam, and a BD (Blu-ray Disc, registered trademark) light beam. Details of the inside of the optical pickup 1 will be described later.

  The signal generation circuit 21 performs arithmetic processing based on the signal obtained by the photodetector 19 (FIG. 2) included in the optical pickup 1, and performs RF signal, FE signal (= focus error signal), tracking error signal, and AS. Various signals such as a signal (= total reflection signal) are generated. The generated various signals are output to the DSP 31. The AS signal is a signal indicating the sum of electric signals corresponding to the total amount of light received by the photodetector 19. The AS signal is a signal of a low frequency component of the RF signal and indicates the reflectance of the optical disc.

  The DSP 31 generates an image signal by performing image processing based on the RF signal input from the signal generation circuit 21 and supplies the image signal to the reproduction processing circuit 32. The reproduction processing circuit performs D / A conversion processing to output an image signal to a monitor (not shown). A signal obtained by the conversion process is output to an external device by the output circuit 33.

  The DSP 31 generates a servo signal based on the FE signal or tracking error signal input from the signal generation circuit 21. For example, a tracking servo signal for performing tracking servo and a focus servo signal for performing focus servo are generated. The generated servo signal is given to the driver 42. Thereby, for example, tracking control and focus control of the objective lens 17 (FIG. 2) included in the optical pickup 1 are performed.

  The system controller 41 controls operations of the optical pickup 1, the feed motor 51, the spindle motor 52, and the like via the DSP 31. The system controller 41 is realized by executing a predetermined program on an arithmetic processing unit such as a plurality of microprocessors.

  The system controller 41 receives information from the operation unit 44 and transmits the information to the DSP 31, and transmits information received from the DSP 31 to the display unit 43. Further, the system controller 41 records information used for various calculations in a recording unit 45 including a semiconductor storage element or the like.

The driver 42 controls driving of the optical pickup 1, the feed motor 51, and the spindle motor 52 based on a servo signal or the like given from the DSP 31. The feed motor 51 drives the optical pickup 1 in the radial direction of the optical disc 2. The spindle motor 52 drives the optical disc 2 in the rotation direction.
<2. About optical pickup configuration>

  FIG. 2 is a schematic diagram showing an optical system of the optical pickup 1 according to the embodiment of the present invention. The optical pickup 1 irradiates the optical disc 2 with a light beam and receives reflected light. Thereby, the information recorded on the recording surface of the optical disc 2 is read.

  The optical pickup 1 includes a first light source 11 a (= light source), a second light source 11 b (= light source), a dichroic prism 12, a collimator lens 13, a beam splitter 14, a rising mirror 15, and a liquid crystal element 16. , Objective lens 17, detection lens 18, photodetector 19, and actuator 20.

  The first light source 11a is a laser diode that can emit a light beam of 650 nm band corresponding to DVD and a light beam of 780 nm band corresponding to CD. The second light source 11b is a laser diode capable of emitting a 405 nm band light beam corresponding to BD.

  In the present embodiment, a two-wavelength integrated laser diode having two light emitting points that can emit light beams of two types of wavelengths is used as the first light source 11a. However, the present invention is not limited to this. For example, a laser diode that emits only a light beam having a single wavelength may be used.

  The dichroic prism 12 transmits the light beam emitted from the first light source 11a that emits the DVD light beam, and reflects the light beam emitted from the second light source 11b that emits the BD light beam. Then, the optical axes of the light beams emitted from the first light source 11a and the second light source 11b are matched. The light beam transmitted or reflected by the dichroic prism 12 is sent to the collimating lens 13.

  The collimating lens 13 converts the light beam transmitted through the dichroic prism 12 into parallel light. Here, the parallel light means light in which all optical paths of the light beams emitted from the first light source 11a and the second light source 11b are substantially parallel to the optical axis. The light beam converted into parallel light by the collimator lens 13 is sent to the beam splitter 14.

  The beam splitter 14 functions as a light separation element that separates an incident light beam, transmits the light beam transmitted from the collimating lens 13, guides it to the optical disk 2 side, and reflects the reflected light reflected by the optical disk 2. Is reflected and guided to the photodetector 19 side. The light beam that has passed through the beam splitter 14 is sent to the rising mirror 15.

  The raising mirror 15 reflects the light beam transmitted through the beam splitter 14 and guides it to the optical disc 2. The rising mirror 15 is inclined by 45 ° with respect to the optical axis of the light beam from the beam splitter 14, and the optical axis of the light beam reflected by the rising mirror 15 is the same as the recording surface of the optical disc 2. It is almost orthogonal. The light beam reflected by the rising mirror 15 is sent to the liquid crystal element 16.

  The liquid crystal element 16 controls the change in the refractive index by applying a voltage to a liquid crystal (neither of which is shown) sandwiched between transparent electrodes, utilizing the property that the liquid crystal molecules change the orientation direction thereof, and the liquid crystal element 16 This element enables control of the phase of the light beam that passes through the element 6.

  By disposing the liquid crystal element 16, it is possible to correct spherical aberration caused by a difference in the thickness of the resin layer that protects the recording surface of the optical disc 2. The light beam that has passed through the liquid crystal element 16 is sent to the objective lens 17.

  The objective lens 17 focuses the light beam transmitted through the liquid crystal element 16 on the recording surface of the optical disc 2. The objective lens 17 can be moved, for example, in the vertical and horizontal directions in FIG. 2 by an actuator 20 to be described later, and its position is controlled based on the focus servo signal and the tracking servo signal.

  The reflected light reflected by the optical disk 2 passes through the objective lens 17 and the liquid crystal element 16 in this order, is reflected by the rising mirror 15, is further reflected by the beam splitter 14, and is reflected on the photodetector 19 by the detection lens 18. The light is condensed to a light receiving element provided in the.

  The photodetector 19 converts light received using a light receiving element such as a photodiode into an electrical signal and outputs the electrical signal to the signal generation circuit 21. The photodetector 19 includes, for example, a light receiving region divided into four parts, and can individually perform photoelectric conversion for each region and output an electric signal.

  The actuator 20 moves the objective lens 17 in the radial direction of the optical disc 2 in accordance with the objective lens drive signal generated and output by the driver 42. The actuator 20 is not limited to this, but here the actuator 20 can drive the objective lens 17 with Lorentz force by passing a drive current through a coil (not shown) in a magnetic field formed by a permanent magnet (not shown). It may be.

The actuator 20 tilts the objective lens 17 so that the optical axis of the light beam emitted from the objective lens 17 swings in addition to the tracking operation for moving the objective lens 17 in the direction along the recording surface of the optical disc 2. A tilting operation and a focusing operation for moving the objective lens 17 toward and away from the optical disc 2 can also be performed.
<3. Mounting process>

  Next, an optical disk mounting process according to an embodiment of the present invention will be described with reference to the flowchart of FIG. This process shown in FIG. 3 is started when the system controller 41 detects that the optical disk 2 is attached to the disk player 100 and when an execution instruction for the mount process is detected.

  In step S110, the system controller 41 that has detected the above instruction instructs the DSP 31 to read identification information for identifying the type of the optical disk 2 from the predetermined recording area of the optical disk 2. Then, the type of the optical disc, for example, the type such as CD or DVD, is determined from the acquired identification information.

  Next, in step S120, the system controller 41 adjusts the amplitude of the FE signal. Further, in step S130, the system controller 41 performs S-shaped balance adjustment of the FE signal.

  The S-shaped balance adjustment is performed using FES and V1 shown in FIG. FES indicates the difference between the maximum value and the minimum value of the FE signal. V1 represents the difference between the maximum value of the FE signal minus FES / 2 and the reference voltage (= GND).

The focus error balance (hereinafter referred to as “FEB”) is calculated by the following calculation formula.
FEB = V1 / FES × 100

  The system controller 41 instructs the DSP 31 to perform a balance adjustment that brings the FEB calculated above close to 0, that is, a balance adjustment that equalizes the waveform of the FE signal vertically. Then, an S-shaped balance adjustment value (= first adjustment value) indicating the content of the balance adjustment performed is recorded in the recording unit 45. The S-shaped balance adjustment value is, for example, a value indicating the number of steps for moving the objective lens 17 to the reference position after balance adjustment.

  Next, in step S140, the system controller 41 instructs the DSP 31 to focus on the recording surface of the optical disc 2 by using the S-shaped balance adjustment value obtained above. Receiving this, the DSP 31 instructs the driver 42 to drive the actuator 20 to control the focus of the objective lens 17.

  Next, in step S150, the system controller 41 performs focus balance adjustment of the FE signal. The focus balance adjustment is performed using the AS signal shown in FIG.

  The system controller 41 instructs the DSP 31 to adjust the optical pickup 1 so that the value of the AS signal is maximized. Then, a focus balance adjustment value (= second adjustment value) indicating the content of the adjustment that has been performed is recorded in the recording unit 45.

In step S150, the system controller 41 performs an adjustment that maximizes the AS regardless of the size of defocus (hereinafter referred to as “DEF”) of the optical pickup 1. The DEF of the optical pickup 1 can be calculated by the following calculation formula.
DEF = V2 / FES × 100
V2 in the above equation (shown in FIG. 5A) shows the difference between the value of the FE signal and the reference voltage that occurs when adjustment is performed to maximize the AS signal shown in FIG. 5B. Yes.

  Next, in step S160, the system controller 41 instructs the DSP 31 to perform the TE system adjustment. Further, in step S170, the DSP 31 is instructed to perform track-on. Further, in step S180, the DSP 31 is instructed to perform various adjustments after the track is turned on, for example, focus gain adjustment and track gain adjustment.

  Next, in step S190, the system controller 41 performs the focus balance adjustment of the FE signal again. Thereby, adjustment accuracy is improved. However, since the processing content itself is the same as that in step S150, the description is omitted here.

In step S200, the system controller 41 instructs the DSP 31 to perform other various adjustments. The various adjustments include, for example, spherical aberration adjustment, RF amplitude adjustment, tilt adjustment, RF equalizer adjustment, focus gain adjustment, track gain adjustment, and the like. When these various adjustments are completed, the mounting is completed and the present process is terminated.
<4. About seek processing>

  Next, an optical disk seek process according to an embodiment of the present invention will be described with reference to the flowchart of FIG. This process shown in FIG. 4 is started when the mounting process of the disc player 100 is completed and a seek process execution instruction is detected.

  In step S310, the system controller 41 that has detected the above instruction in step S310 preliminarily records the S-shaped balance adjustment value (= value acquired in step S130) and the focus balance adjustment value (= obtained in step S190). Value) is read from the recording unit 45, and an adjustment value difference (= difference value) indicating a difference between the two values is calculated.

  In step S320, it is determined whether or not the adjustment value difference exceeds a predetermined threshold value α. It is assumed that the value of α is determined from the average value of the optical disc or the set based on experimental data performed at the time of manufacture of the disc player 100, and is recorded in advance in the recording unit 45 or the like. The system controller 41 reads this threshold value α from the recording unit 45 and performs the above determination.

  When the adjustment value difference does not exceed the threshold value α, the process proceeds to step S340 described later. When the adjustment value difference exceeds the threshold value α, the system controller 41 performs setting in step S330 so that the S-shaped balance adjustment value is used as the adjustment value used during seek.

  Next, in step S340, the system controller 41 instructs the DSP 31 to perform seek processing using the S-shaped balance adjustment value or the focus balance adjustment value. The details of the seek process are the same as those of the prior art, and the description thereof is omitted here.

  When the seek process is completed, in step S350, the system controller 41 performs setting so that the focus balance adjustment value is used as an adjustment value used for the subsequent processes. Thereby, the S-shaped balance adjustment value temporarily set is returned to the focus balance adjustment value. When the setting is completed, this process is terminated.

According to the present embodiment described above, when the difference between the S-shaped balance adjustment value and the focus balance adjustment value is large, the setting is changed so that seek processing is performed using the S-shaped balance adjustment value. The setting has been changed to return to the focus balance adjustment value. This increases the stability of the servo during seeking. Therefore, even when the defocus is large due to the characteristics of the optical pickup 1 and the optical disc 2, it is possible to suppress the servo detachment at the time of seek.
[Other embodiments]

  The present invention has been described with reference to the preferred embodiments and examples. However, the present invention is not necessarily limited to the above embodiments and examples, and various modifications may be made within the scope of the technical idea. Can be implemented.

  Therefore, the present invention can also be applied to the following embodiments.

  (A) In the above embodiment, each function related to the mount processing and seek processing of the present invention is realized by executing a program on an arithmetic processing unit such as a microprocessor. It may be a form realized by.

  (B) In the above embodiment, the disk player 100 is exemplified as the optical disk apparatus that performs the mounting process and the seek process of the present invention, but the present invention may be implemented in other optical disk apparatuses. For example, it may be implemented in a DVD recorder that records on an optical disk.

  (C) In the above embodiment, the adjustment value difference is calculated and the adjustment value difference is compared with the threshold value α every time a seek process execution instruction is detected. For example, when the mount process is completed, The calculation and comparison may be performed in advance, and the determination result may be recorded in the recording unit 45 or the like.

100 disc player (optical disc device)
1 Optical pickup 2 Optical disc 11a First light source (light source)
11b Second light source (light source)
17 Objective Lens 19 Photodetector 20 Actuator 21 Signal Generation Circuit (Signal Generation Unit)
31 DSP (servo control unit)
41 System controller (main control unit)
45 Recording section

Claims (3)

An optical pickup including a light source for irradiating a recording surface of an optical disc with a light beam, and a photodetector for photoelectrically converting reflected light from the recording surface;
From the electrical signal obtained by the photoelectric conversion, a total reflection signal indicating the amount of the reflected light, and a signal generation unit that generates a focus error signal;
In an optical disc apparatus comprising a servo control unit that controls the optical pickup based on the total reflection signal and the focus error signal,
A first adjustment value that is an adjustment value for adjusting the optical pickup so that an error balance of the focus error signal is minimized, and an adjustment value for adjusting the optical pickup so that the total reflection signal is maximized. In a process of a predetermined type when a difference value with a certain second adjustment value is calculated, it is determined whether the difference value exceeds a predetermined threshold value, and the difference value exceeds the threshold value. A main control unit that controls the servo control unit to adjust the optical pickup using the first adjustment value ;
A recording unit for recording information;
The main control unit acquires the first adjustment value and the second adjustment value during the mounting process of the optical disc mounted on the optical disc apparatus, records the first adjustment value and the second adjustment value, and records the first adjustment value and the second adjustment value. Calculating the difference value from an adjustment value, and controlling the servo control unit to adjust the optical pickup using the first adjustment value during a seek process when the difference value exceeds a predetermined threshold value And
The main control unit adjusts the optical pickup after the seek process when the adjustment of the optical pickup during the seek process is performed based on the first adjustment value and the seek process is completed. An optical disc apparatus, wherein the servo control unit is controlled so as to be performed according to a value . The main control unit controls the servo control unit to adjust the optical pickup using the second adjustment value during a seek process when the difference value does not exceed a predetermined threshold value.
The optical disc apparatus according to claim 1. In the adjustment of the optical pickup so that the error balance of the focus error signal is minimized, the difference between the maximum value and the minimum value of the focus error signal is subtracted from the maximum value of the focus error signal. Done using the difference between the value and the reference voltage,
The adjustment of the optical pickup so that the total reflection signal is maximized is performed using a difference between a value of the focus error signal and a reference voltage at which the total reflection signal is maximized,
The optical disc apparatus according to claim 1 or 2.

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