JP2010238286A - Optical disk device, and attraction determining means of optical disk - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk device and an attraction determining method of the optical disk by which the attraction state of an optical disk and a stabilizing plate can easily be detected and the stable recording and reproducing of information signals can be performed. <P>SOLUTION: The optical disk device includes a RF circuit part, a focus S character signal detector, and an attraction determining means. The RF circuit part generates a focus error signal based on a reflected signal projected to the optical disk in which wobbling is suppressed by the stabilizing plate. The focus S character signal detector detects a focus S character signal appearing in the focus error signal. The attraction determining means determines whether both of the optical disk and the stabilizing plate are absorbed or not based on at least one side of the number of times of detection or detection interval of the focus S character signal. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical disc apparatus for driving a flexible optical disc and an optical disc adsorption determination method.

  In recent years, there has been an increasing demand for an increase in the capacity of an optical disc accompanying the digitization of information, that is, an increase in the density of information recorded on the optical disc, such as the start of digitization of television broadcasting. A main measure for this requirement is to reduce the spot diameter of light used for recording / reproduction.

  In order to reduce the spot diameter of light, it is effective to shorten the wavelength and increase the numerical aperture (NA) of the objective lens. As for the wavelength of light, near infrared light (for example, light having a wavelength near 780 nm) is used for CD (Compact Disc), and red light (for example, light having a wavelength near 650 nm) is used for DVD (Digital Versatill Disc). . Recently, blue light (light having a wavelength near 400 nm) has been used in BD (Blu-ray Disc) and HDDVD (High Definition DVD). Regarding the objective lens, the NA of the objective lens for CD is less than 0.5, and the NA of the objective lens for DVD and HDDVD is about 0.6. The NA of the objective lens for BD is gradually increased to about 0.85. However, there is a limit to further shortening the wavelength and increasing the NA. It has become difficult to reduce the spot diameter of light beyond this. Therefore, in order to cope with the future increase in capacity, research for increasing the density per volume has begun.

  From such a background, development of a thin optical disk in which a recording surface is formed on a thin film sheet is underway. A thin optical disk has flexibility and is likely to cause surface blurring. There has been proposed an optical disc driving technique in which such a thin optical disc is rotated on a stabilizing plate (stabilizer) so as to suppress surface deflection of the optical disc.

  This thin optical disk is attached to a rotational drive device, and is rotated by the rotational drive device when an information signal is reproduced from the thin optical disk. In order to stabilize the state of the thin optical disk during rotational driving, a stabilization plate is disposed in the vicinity of the thin optical disk.

  The stabilization plate is disposed substantially parallel to the thin optical disk so as to face the surface on the laser light incident side of the surface of the thin optical disk. The stabilizing plate has a flat surface facing the thin optical disk. That is, the thin optical disk rotates in the vicinity of a stabilizing plate having a flat surface facing the thin optical disk.

  As shown in FIG. 1, the stabilizing plate 117 has a disk shape as in the conventional optical disc, and has a fine hole around the center hole. In addition, as shown in FIG. 2, the stabilization plate 117 is disposed at a position where the laser light applied to the thin optical disk is transmitted, and thus is made of glass having a high transmittance of about 500 μm. Yes.

  When reproducing an information signal from the thin optical disk 101, a laser beam is irradiated from a light source to the thin optical disk 101 that is rotationally driven at a position close to the stabilization plate 117. Then, the reflected light is collected on the photodetector. A change in the intensity of light incident on the photodetector is detected, and the information signal recorded on the thin optical disk is reproduced.

  The stabilizing plate 117 and the thin optical disk 101 are separated when rotated. As shown in FIG. 2, air flows between the stabilization plate 117 and the thin optical disc 101, and the distance between the thin optical disc 101 and the stabilization plate 117 is kept uniform over the entire surface. At this time, the distance between the stabilizing plate 117 and the thin optical disk 101 is 100 to 300 μm. By adjusting how to make fine holes around the central hole of the stabilizing plate 117, a predetermined distance within the range can be set with an accuracy of several tens of nanometers.

  In such a thin optical disk recording / reproducing apparatus, since the stabilization plate 117 rotates close to the thin optical disk 101, the air passing through the fine holes around the central hole of the stabilization plate 117 is stabilized by the stabilization plate 117. And the thin optical disk 101. Therefore, due to the Bernoulli effect, the thin optical disk 101 can be stably rotated while maintaining a certain distance from the stabilizing plate 117. Therefore, the surface shake of the thin optical disk during rotation driving can be suppressed to a very small level. As described above, in this thin optical disk recording / reproducing apparatus, surface blurring during rotation driving of the thin optical disk can be suppressed, so that stable information signal recording / reproduction can be performed.

  However, static electricity is generated between the thin optical disc 101 and the stabilization plate 117 due to friction caused by air flowing between the thin optical disc 101 and the stabilization plate 117, contact between the thin optical disc 101 and the stabilization plate 117, and the like. The stabilization plate may attract the thin optical disk 101.

  When recording / reproduction is attempted with the stabilization plate 117 adsorbing the thin optical disk, there is a possibility that track pull-in fails and recording / reproduction of the thin optical disk 101 cannot be performed. Moreover, even if the track pull-in is successful, there is a possibility that the recording / reproducing performance may not be achieved.

  Further, if the thin optical disk 101 is removed while the stabilization plate 117 is attracting the thin optical disk 101, the thin optical disk 101 is forcibly removed from the stabilization plate 117, and the thin optical disk 101 may be damaged. There is.

  Japanese Unexamined Patent Application Publication No. 2003-006903 discloses a technique related to an optical disc apparatus that performs recording or reproduction on a flexible optical disc. This optical disc apparatus includes a rotation driving means, an optical pickup, and a stabilizing plate. The rotation driving means rotates the flexible optical disk. The optical pickup includes a slider that is disposed to face the flexible optical disk and that has a flat surface facing the flexible optical disk. The optical pickup is used for recording or reproducing light on the flexible optical disk. Condensing means for condensing light is provided. The stabilizing plate is disposed opposite to the flexible optical disk on the side opposite to the optical pickup side of the flexible optical disk, and the surface facing the flexible optical disk is a flat surface.

  Japanese Patent Application Laid-Open No. 2003-338165 discloses a technique related to an optical disk drive stabilization device. This optical disk drive stabilization device is an optical disk drive stabilization device that includes a rotation drive means and a stabilization means, and uses a protruding member that protrudes in the direction of the optical disk as the stabilization means. The rotation driving means rotates a flexible sheet-like optical disk. The stabilizing means is installed on the side opposite to the recording surface of the optical disc, and stabilizes at least a vibration in the direction of the rotation axis in a portion where writing or reading is performed on the optical disc by causing a pressure difference of the air flow. The sensing means senses the contact pressure between the projecting member and the optical disk, and the retracting means retracts the projecting member from the optical disk surface when a contact pressure equal to or higher than a preset threshold is sensed by the sensing means.

  An optical disc apparatus using a focus S-shaped signal is described in, for example, Japanese Patent Application Laid-Open No. 2007-141347. This optical disc apparatus has two or more light sources having different wavelengths for optically recording / reproducing plural types of optical disc media having different light wavelengths used for recording / reproducing. This optical disk medium includes a substrate or cover layer having light transmittance and at least one information recording layer for optically recording information on a surface of the substrate or cover layer opposite to the light incident side. This optical disc apparatus includes a focus S-shaped signal detection unit and a layer number determination unit. The focus S-shaped signal detection means performs a focus search using a light source having a predetermined wavelength among the two or more light sources, and detects a focus S-shaped signal. The light source of a predetermined wavelength is the amount of light irradiated to the substrate or cover layer when the light is irradiated to the information recording layer farthest from the light incident surface of the optical disc medium having a plurality of information recording layers, and the farthest information. It is a light source having a wavelength with the highest ratio to the amount of light reflected from the recording layer and emitted from the substrate or the cover layer. The number-of-layers determining unit determines the number of information recording layers based on the number of appearances of the focus S-shaped signal.

JP 2003-006903 A JP 2003-338165 A JP 2007-141347 A

  An object of the present invention is to provide an optical disc apparatus and an optical disc adsorption determination method capable of solving the above-described problems, easily detecting the adsorption state between an optical disc and a stabilizing plate, and recording and reproducing stable information signals. is there.

  In an aspect of the present invention, the optical disc apparatus includes an RF circuit unit, a focus S-shaped signal detector, and a suction determination unit. The RF circuit unit generates a focus error signal based on the reflected light of the light emitted toward the optical disk whose surface vibration is suppressed by the stabilizing plate. The focus S-shaped signal detector detects a focus S-shaped signal that appears in the focus error signal. The adsorption determination unit determines whether or not the optical disc and the stabilization plate are adsorbed based on at least one of the number of detections of the focus S-shaped signal and the detection interval.

  In another aspect of the present invention, an optical disk adsorption determination method includes a generating step, a detecting step, and a determining step. In the generating step, a focus error signal is generated based on the reflected light of the light emitted toward the optical disc whose surface vibration is suppressed by the stabilizing plate. In the detecting step, a focus S-shaped signal appearing in the focus error signal is detected. In the determining step, it is determined whether or not the optical disc and the stabilizing plate are adsorbed based on at least one of the number of detections of the focus S-shaped signal and the detection interval.

  According to the present invention, it is possible to provide an optical disc apparatus and an optical disc adsorption determination method capable of easily detecting the adsorption state between the optical disc and the stabilizing plate and stably recording and reproducing information signals.

It is a figure which shows the shape of the stabilization board used with a thin optical disk apparatus. It is a figure which shows the positional relationship of the thin optical disk in operation | movement and a stabilization board. It is a figure which shows the structure of the thin optical disk apparatus based on embodiment of this invention. It is a figure which shows the change of a focus error signal when an objective lens is moved to a focus direction. It is a figure which shows the change of a focus error signal when an objective lens is moved to a focus direction in the case of attracting | sucking. It is a figure which shows the operation | movement of adsorption | suction determination of a thin optical disk apparatus. It is a figure which shows the change of a focus error signal when an objective lens is moved to a focus direction with the thin optical disk which has two recording layers. It is a figure which shows the operation | movement of adsorption | suction determination of a thin optical disk apparatus.

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

  FIG. 3 shows a schematic configuration of a thin optical disk device 100 according to the embodiment of the present invention. The thin optical disk device 100 rotates the thin optical disk 101 and the stabilizing plate (stabilizer) 117 to be loaded, records information on the thin optical disk 101, and reproduces information from the thin optical disk 101. Here, description regarding the recording / reproducing function is omitted.

  The thin optical disk device 100 includes a rotation drive device 102, a servo drive system 103, a servo controller 104, a system controller 105, an LD drive unit 106, an RF circuit unit 107, a thread motor 108, and an optical head 113. The optical head 113 includes an objective lens actuator 109, a beam splitter 110, a laser diode (LD) 111, and a photodetector 112.

  The laser diode 111 emits laser light having a wavelength of blue light (405 nm). The photodetector 112 detects reflected light incident from the thin optical disk 101. The beam splitter 110 guides the light output from the laser diode 111 to the objective lens 123 and allows the reflected light incident from the thin optical disk 101 to pass toward the photodetector 112.

  The objective lens actuator 109 drives the objective lens 123 in the focus direction and the track direction. The rotation drive device 102 rotates the thin optical disk 101 and the stabilization plate 117. The sled motor 108 moves the optical head 113 in the radial direction of the thin optical disk 101.

  The servo controller 104 generates a control signal for controlling the objective lens actuator 109 based on the servo error signal and supplies it to the servo drive system 103. Further, the servo controller 104 includes a focus S-shaped signal detector 115 corresponding to the focus S-shaped signal detecting means and a distance calculator 114 corresponding to the distance calculating means. The focus S-shaped signal detector 115 determines the presence or absence of a focus S-shaped signal (sometimes referred to as an S-shaped curve, S-shaped signal, or focus S-shaped) based on the focus error signal and the amount of reflected light. The distance detector 114 measures the appearance position of the focus S-shaped signal.

  The servo drive system 103 drives the objective lens actuator 109 based on the control signal supplied from the servo controller 104. The LD driving unit 106 drives the laser diode 111. The RF circuit unit 107 generates a servo error signal and a BCA (Burst Cutting Area) signal based on the signal output from the photodetector 112. The system controller 105 controls the entire apparatus. Further, the system controller 105 includes a suction determination unit 116 corresponding to a suction determination unit. The adsorption determination unit 116 determines whether the stabilization plate 117 and the thin optical disk 101 are adsorbed based on information measured by the focus S-shaped signal detector 115 and the distance calculator 114. When it is determined that the suction is performed, the system controller 105 notifies the display function (not shown) in the thin optical disk device that the suction is performed, and the suction state is indicated to the outside.

  The focus S-shaped signal detector 115 determines whether or not there is a focus S-shaped signal as will be described below. In the focus S-shaped signal detector 115, two thresholds for the focus error signal and one threshold for the sum signal indicating the amount of reflected light are set in order to determine the presence or absence of the focus S-shaped signal. As the former two threshold values, threshold values are set to predetermined voltages above and below the electrical neutral position of the focus error signal. The upper threshold value is set lower than the maximum value of the focus error signal, and the lower threshold value is set higher than the minimum value of the focus error signal. As the latter threshold value, a sum signal threshold value is set between the maximum value and the minimum value for the sum signal obtained by summing the reflected light amounts. The presence or absence of the focus S-shaped signal can be determined by the lowering after the focus error signal exceeds the upper threshold, the upper after the lower threshold, and the sum signal exceeding the sum signal threshold. That is, when the amplitude of the focus error signal fluctuates beyond the upper and lower threshold ranges and the reflected light amount sum signal exceeds the sum signal threshold value, it is determined that there is a focus S-shaped signal.

  The focus S-shaped signal detector 115 counts the number of times the focus S-shaped signal has appeared, and stores the amplitude of the sum signal at that time. FIG. 4 shows how the focus error signal changes when the objective lens 123 is moved in the focus direction. Here, a case where the objective lens 123 is driven in a direction approaching the thin optical disc 101 from a position far from the stabilization plate 117, that is, a state where the focal position of the laser beam does not reach the stabilization plate 117 will be described. To do.

  Here, in order to simplify the description, the surface on the side close to the objective lens 123 of the stabilization plate 117 that is the incident surface of the laser light is defined as A surface, and the surface on the side away from the objective lens 123 of the stabilization plate 117. Is B side. Further, the disk surface near the stabilization plate 117 of the thin optical disk 101, here, the surface near the stabilization plate 117 of the cover layer 12 is defined as a C surface, and the recording layer 14 of the thin optical disk 101 is defined as a D surface. Therefore, the B surface of the stabilizing plate 117 and the C surface of the thin optical disk 101 face each other with an air layer interposed therebetween. Here, the C surface of the thin optical disk 101 facing the B surface is the surface of the cover layer 12, but in the case of the thin optical disk 101, the cover layer 12 may be a substrate. A focus S-shaped signal appears corresponding to these surfaces.

  The thickness of the stabilizing plate 117 (the distance between the A plane and the B plane) is 500 μm. The thickness from the C surface indicating the disk surface of the thin optical disk 101 to the D surface indicating the recording layer 14 is 100 μm. The gap between the B surface and the C surface is set to 200 μm.

  When the thin optical disk 101 is not attracted to the stabilization plate 117, the focus of the laser beam is focused on the A surface that is the surface facing the objective lens 123 of the stabilization plate 117, as shown in FIG. A focus S-shaped signal A is observed at the position. Thereafter, the focus of the laser beam is focused on the B surface which is the surface facing the thin optical disk 101 of the stabilizing plate 117, and the focus S-shaped signal B is observed. Next, the focus S of the laser beam is focused on the C-plane which is the substrate surface of the thin optical disc 101, and the corresponding focus S-shaped signal C is observed. Thereafter, the focus of the laser beam is focused on the D surface, which is the recording layer 14 of the thin optical disc 101, and the focus S-shaped signal D is observed. Therefore, when the thin optical disk 101 is not attracted to the stabilizing plate 117, focus S-shaped signals are observed at four positions.

  However, as shown in FIG. 5, when the thin optical disk 101 is adsorbed to the stabilization plate 117, the focus S observed at two places, the B surface of the stabilization plate 117 and the C surface of the thin optical disk 101. Character signal is observed only at one place. Therefore, in the case of the suction state, the focus S-shaped signal A corresponding to the A plane, the focus S-shaped signal B corresponding to the B plane / C plane, and the focus S-shaped signal D corresponding to the D plane are three places. A focus S-shaped signal is observed.

  Even when the thin optical disk 101 has two recording layers 14, there are A, B, and C surfaces between the objective lens 123 and the recording layer 14. Therefore, as in the case where the recording layer 14 is a single layer, when the recording layer 14 is not attracted, the focus S-shaped signal including the focus S-shaped signal corresponding to the recording layer 14 close to the objective lens 123 has four locations. If it is adsorbed, it is observed at three locations.

  Therefore, as shown in FIG. 6, the adsorption state between the stabilizing plate 117 and the thin optical disk 101 can be confirmed by observing the number of appearances of the focus S-shaped signal. That is, first, when the stabilization plate 117 and the thin optical disk 101 are set in the thin optical disk device 100, the rotation driving device 102 rotates the thin optical disk 101 and the stabilization plate 117 (step S12).

  The LD driving unit 106 drives the laser diode 111 to irradiate the thin optical disc 101 with a blue light beam (step S14).

  The servo drive system 103 drives the objective actuator 109 based on the control signal supplied from the servo controller 104 to move the objective lens 123 toward the thin optical disc 101 in the focus direction (step S16). The servo controller 104 controls the servo drive system 103 so that the position where the laser beam is focused by the objective lens 123 moves toward the thin optical disk 101 at a constant speed. Accordingly, the distance can be calculated based on the time for detecting the focus S-shaped signal. For example, the servo controller 104 detects the focus S-shaped signal A corresponding to the A surface of the stabilizing plate 117 by a timer (not shown) and then focuses the S-shaped signal D on the recording layer 14 (D surface) of the thin optical disk 101. Measure the time until is observed. Based on the time, the distance from the A plane to the D plane is calculated.

  The RF circuit unit 107 generates a focus error signal from the signal detected by the photodetector 112 based on the reflected light. The focus S-shaped signal detector 115 observes the focus S-shaped signal based on the focus error signal (step S18). That is, the focus S-shaped signal detector 115 determines the presence or absence of a focus S-shaped signal based on the focus error signal and the amount of reflected light, and counts the number of detections.

  Further, the focus S-shaped signal detector 115 determines whether or not a focus S-shaped signal corresponding to the recording layer 14 is detected (step S22). The focus S-shaped signal corresponding to the recording layer 14 has a larger amplitude than the focus S-shaped signal corresponding to the other surface, and the amplitude of the sum signal when the focus S-shaped signal is detected is also large. Can do.

  If the detected focus S-shaped signal is not the focus S-shaped signal D corresponding to the recording layer 14 (step S22-No), the observation of the focus S-shaped signal is continued while the objective lens 123 is further moved. When the detected focus S-shaped signal is the focus S-shaped signal D corresponding to the recording layer 14 (step S22—Yes), the focus S-shaped signal detector 115 detects the focus S-shaped signal detected so far. The number is notified to the suction determination unit 116 of the system controller 105. At this time, it is preferable that the distance calculator 114 notifies the suction determination unit 116 of information regarding the position where each focus S-shaped signal is detected.

  The suction determination unit 116 determines the suction state between the stabilization plate 117 and the thin optical disk 101 based on the number of appearances of the focus S-shaped signal (step S24). As shown in FIG. 4, when four signals of the focus S-shaped signals A to D including the focus S-shaped signal D corresponding to the recording layer 14 have appeared so far, the suction determination unit 116 is stable. It is determined that the chemical conversion plate 117 and the thin optical disk 101 are not adsorbed. As shown in FIG. 5, when only three signals of the focus S-shaped signals A, B, D including the focus S-shaped signal D corresponding to the recording layer 14 have been detected so far, the suction determination unit 116 Then, it is determined that the stabilization plate 117 and the thin optical disk 101 are adsorbed.

  Further, the suction state can be determined by referring to the distance between the A surface or B surface of the stabilizing plate 117 and the D surface of the recording layer 14. The thickness of the stabilizing plate 117 is 500 μm, the distance between the B surface and the C surface is 100 μm at the shortest, and the distance between the C surface and the D surface is 100 μm. The distance between them is 700 μm at the shortest, and 600 μm in the adsorption state. Therefore, when the appropriate value of 600 to 700 μm is set as a threshold value and the measured distance between the A plane and the D plane is equal to or less than the threshold value, it can be determined that the stabilizing plate 117 and the thin optical disk are adsorbed. That is, the suction determination unit 116 can determine the suction state by comparing the measured distance between the A plane and the D plane and the threshold value. Further, the suction state can be determined with high accuracy by combining the number of appearance of the focus S-shaped signal and the distance to the recording layer 14. In addition to the distance between the A plane and the D plane, the determination may be made based on the distance between the B plane and the D plane, the distance between the A plane and the C plane, and the distance between the B plane and the C plane. And the distance between the A plane and the D plane is easy as a criterion for determination.

  When the number of recording layers 14 of the thin optical disk 101 is known, it is possible to determine whether or not the suction state is established only by the number of appearance of the focus S-shaped signal. For example, as shown in FIG. 7, in the case of a thin optical disc 101 having two recording layers 14, focus S-shaped signals appear at five locations. That is, when the focal point of the laser beam is moved from the objective lens 123 side toward the thin optical disc 101 side, first, a focus S-shaped signal A corresponding to the A surface that is the surface of the stabilization plate 117 on the objective lens 123 side is obtained. Appear. Next, a focus S-shaped signal B corresponding to the B surface which is the surface of the stabilizing plate 117 on the thin optical disk 101 side appears. Further, a focus S-shaped signal C appears corresponding to the C surface which is the disk surface of the thin optical disk 101. Then, focus S-shaped signals D and E appear corresponding to the two recording layers 14 (the recording layer closer to the light source is the D surface and the far recording layer is the E surface).

  Among them, the focus S-shaped signal A, the focus S-shaped signal D, and the focus S-shaped signal E are detected regardless of the suction state, and the focus S-shaped signal B and the focus S-shaped signal C are thin with the stabilization plate 117. When the optical disk 101 is adsorbed, it cannot be distinguished and is detected as one focus S-shaped signal. That is, assuming that the number of recording layers 14 is N, N + 3 focus S-shaped signals appear when the thin optical disk 101 is not attracted to the stabilizing plate 117, and N + 2 appear when it is attracted. To do. Note that when the focal point is moved to a surface far from the light source of the thin optical disk 101, a focus S-shaped signal is further detected, but here, the detection of the focus S-shaped signal is stopped before that.

  Therefore, as shown in FIG. 8, the adsorption state can be determined if the number of recording layers 14 is known without determining whether or not the focus S-shaped signal corresponds to the recording layer 14. . Steps S12 to S18 shown in FIG. 8 are the same as steps S12 to S18 shown in FIG. 6, but will be described again.

  First, when the stabilization plate 117 and the thin optical disk 101 are set in the thin optical disk device 100, the rotation driving device 102 rotates the thin optical disk 101 and the stabilization plate 117 (step S12).

  The LD driving unit 106 drives the laser diode 111 to irradiate the thin optical disc 101 with a blue light beam (step S14).

  The servo drive system 103 drives the objective actuator 109 based on the control signal supplied from the servo controller 104 to move the objective lens 123 toward the thin optical disc 101 in the focus direction (step S16). Also in this case, the servo controller 104 controls the servo drive system 103 so that the position where the laser beam is focused by the objective lens 123 moves toward the thin optical disk 101 at a constant speed. Thereby, the range in which the focus S-shaped signal is observed can be set according to the movement time.

  The RF circuit unit 107 generates a focus error signal from the signal detected by the photodetector 112 based on the reflected light. The focus S-shaped signal detector 115 observes the focus S-shaped signal based on the focus error signal (step S18). That is, the focus S-shaped signal detector 115 determines the presence or absence of a focus S-shaped signal based on the focus error signal and the amount of reflected light, and counts the number of detections.

  Further, the servo controller 104 determines whether or not the distance calculated by the distance calculator 114 has reached a predetermined distance (step S32). If it has not moved to the predetermined distance (step S32-No), the observation of the focus S-shaped signal is continued while further moving the objective lens 123. When the predetermined distance is reached (step S32—Yes), the focus S-shaped signal detector 115 notifies the suction determination unit 116 of the system controller 105 of the detected number of focus S-shaped signals detected so far. At this time, it is preferable that the distance calculator 114 notifies the suction determination unit 116 of information regarding the position where each focus S-shaped signal is detected.

  The suction determination unit 116 determines the suction state between the stabilization plate 117 and the thin optical disk 101 based on the number of appearances of the focus S-shaped signal (step S34). As described above, when the number of recording layers 14 is N, when N + 3 focus S-shaped signals are detected, there is no adsorption between the stabilizing plate 117 and the thin optical disk 101, and only N + 2 focus S-shaped signals are detected. If the signal cannot be detected, the adsorption determination unit 116 determines that the thin optical disk 101 is adsorbed on the stabilization plate 117.

  Thus, when the number of recording layers is known, the adsorption state between the stabilizing plate 117 and the thin optical disk 101 can be determined only by the number of detected focus S-shaped signals. If the number of recording layers is known, the signal corresponding to the number of layers can be estimated from the last detected focus S-character signal as a focus S-character signal corresponding to the recording layer. The distance between the stabilizing plate 117 and the recording layer can be calculated from the signal appearance timing, and the suction state can be determined with higher accuracy by putting the distance in the determination condition.

  If the thin optical disk 101 is completely adsorbed on the stabilizing plate 117, it can be determined by performing the above procedure once. However, if it is partially adsorbed, it cannot always be determined. Absent. That is, if the observed portion is not adsorbed, it is determined that the adsorbed state is not present even if other portions are adsorbed. Therefore, it is preferable to observe over many places, not just at one place. It is preferable to determine the adsorption state when the measurement is performed at multiple locations and the adsorption state is detected even at one location.

  As described above, according to the present invention, it is possible to provide an optical disc apparatus and an optical disc adsorption determination method that can easily detect the adsorption state between the optical disc and the stabilizing plate and perform stable recording and reproduction.

12 Cover layer 14 Recording layer 16 Substrate 100 Thin optical disk device 101 Thin optical disk 102 Rotation drive device 103 Servo drive system 104 Servo controller 105 System controller 106 LD drive unit 107 RF circuit unit 108 Thread motor 109 Objective lens actuator 110 Beam splitter 111 Laser diode 112 Photodetector 113 Optical head 114 Distance calculator 115 Focus S-shaped signal detector 116 Adsorption determination unit 117 Stabilizing plate 123 Objective lens

Claims (12)

An RF circuit unit that generates a focus error signal based on the reflected light of the light emitted toward the optical disc whose surface vibration is suppressed by the stabilizing plate;
A focus S-shaped signal detector for detecting a focus S-shaped signal appearing in the focus error signal;
An optical disc apparatus comprising: an adsorption determination unit that determines whether or not the optical disc and the stabilization plate are adsorbed based on at least one of the number of detection times and the detection interval of the focus S-shaped signal. The optical disc includes a recording layer,
The adsorption determination unit determines whether the optical disc and the stabilization plate are based on the number of detections of the focus S-shaped signal detected when the focus of the light is between the recording layer and the stabilization plate. The optical disc apparatus according to claim 1, wherein it is determined whether or not the suction is performed. Further comprising a distance calculator for calculating a distance between the reflecting surfaces on which the focus S-shaped signal appears based on the detection interval of the focus S-shaped signal;
The optical disc includes a recording layer,
The distance calculator calculates a distance between the stabilizing plate and the recording layer based on a focus S-shaped signal corresponding to the stabilizing plate and a focus S-shaped signal corresponding to the recording layer;
3. The optical disc apparatus according to claim 1, wherein the adsorption determination unit determines whether or not the optical disc and the stabilization plate are adsorbed based on a distance between the stabilization plate and the recording layer. . A light source that emits the light;
An objective lens that collects the light while moving along the optical axis of the light;
A photodetector for detecting the reflected light, and
The focus S-shaped signal detector is configured such that the focus of the light is from a position closer to the light source than a surface on the light source side of the stabilizing plate to a time when the focus of the light is at the position of the recording layer. Detect S-shaped signal,
The adsorption determination unit determines whether the optical disc and the stabilization plate are adsorbed when the focus S-shaped signal detector detects a focus S-shaped signal corresponding to the recording layer. Alternatively, the optical disk device according to claim 3. When the number of recording layers of the optical disc is known to be N,
The focus S-shaped signal detector detects the focus S-shaped signal appearing in a predetermined range;
The optical disc apparatus according to claim 1, wherein the adsorption determination unit determines that the optical disc and the stabilization plate are adsorbed when the number of detection times of the focus S-shaped signal is N + 2. The optical disc apparatus according to claim 1, further comprising a display unit that indicates to the outside that the optical disc and the stabilization plate are adsorbed. Generating a focus error signal based on the reflected light of the light emitted toward the optical disc whose surface vibration is suppressed by the stabilizing plate;
Detecting a focus S-shaped signal appearing in the focus error signal;
Determining whether or not the optical disc and the stabilization plate are adsorbed based on at least one of the number of detection times and the detection interval of the focus S-shaped signal. The optical disc includes a recording layer,
In the determining step, the optical disc and the stabilization plate are based on the number of detections of the focus S-shaped signal detected when the focus of the light is between the recording layer and the stabilization plate. The optical disk adsorption determination method according to claim 7, further comprising a step of determining whether or not the optical disk is adsorbed. Further comprising the step of calculating a distance between the reflecting surfaces on which the focus S-shaped signal appears based on the detection interval of the focus S-shaped signal;
The optical disc includes a recording layer,
The calculating step includes a step of calculating a distance between the stabilizing plate and the recording layer based on a focus S-shaped signal corresponding to the stabilizing plate and a focus S-shaped signal corresponding to the recording layer. ,
The determination step includes a step of determining whether or not the optical disc and the stabilization plate are adsorbed based on a distance between the stabilization plate and the recording layer. Method for determining adsorption of optical discs. Emitting the light from a light source;
Collecting the light while moving along the optical axis of the light;
Detecting the reflected light; and
The detecting step includes the focus S-shaped signal from when the focus of the light is at a position closer to the light source than the surface of the stabilization plate on the light source side to when the focus of the light is at the position of the recording layer. The step of detecting
The step of determining includes a step of determining whether or not the optical disc and the stabilization plate are adsorbed when a focus S-shaped signal corresponding to the recording layer is detected. The method for determining adsorption of an optical disk as described in 1. When the number of recording layers of the optical disc is known to be N,
The detecting step includes a step of detecting the focus S-shaped signal appearing in a predetermined range,
The optical disc adsorption determination method according to claim 7, wherein the determining step includes a step of determining that the optical disc and the stabilization plate are adsorbed when the number of detection times of the focus S-shaped signal is N + 2. The method for determining whether or not the optical disk is sucked according to claim 7, further comprising a step of displaying to the outside that the optical disk and the stabilizing plate are sucked.

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