JP2007310938A - Optical disk unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk unit which can readily and quickly detect the position of an optical pick up device, trim weight, and to reduce the thickness. <P>SOLUTION: The optical disk unit comprises the optical pick up device 70 for reproducing or recording information to an optical disk 4 which is an information recording/reproducing medium, a spindle motor 40 for rotating the optical disk, a pick up driving device 90 for moving the optical pick up device across inner and outer peripheries of the optical disk, a light-emitting element 104 for emitting a light to the spindle motor, a light-receiving element 102 for receiving the light emitted by the light-emitting element and reflected from the spindle motor, a reflection type sensor 100 installed in the optical pick up device, and a determining section for determining the position of the optical pick up device, by detecting the distance between the optical pick up device and the spindle motor, based on the output of the reflection type sensor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical disc apparatus.

  An optical disk device is a drive device for an optical disk that is an information recording / reproducing medium such as a CD or a DVD, and is a device that records information on the optical disk and reproduces the information recorded on the optical disk. The optical disc apparatus has an optical pickup device that reproduces information recorded on the optical disc and records information on the optical disc, and a pickup drive device that drives the optical pickup device. The optical pickup unit is moved by driving a pickup driving device. There are various methods for detecting the position of the optical pickup unit, such as a method using a mechanical detector and a method using a photo interrupter.

  For example, in Patent Document 1, in an optical disc apparatus having a detection unit provided on a flexible substrate connected to an optical pickup and a detection unit provided on a main substrate, the detection unit detects the detection unit. Discloses a method for detecting the position of an optical pickup. Further, in Patent Document 2, in an optical disc apparatus including a reflection type photosensor provided in a mechanical chassis and a reflection mechanism provided in an optical pickup, output light of a light emitting element of the reflection type photosensor is reflected by the reflection mechanism. Then, a method for detecting that the optical pickup is located at the innermost circumference by being incident on the light receiving element of the reflective photosensor is disclosed.

JP 11-238329 A Japanese Unexamined Patent Publication No. 2000-67437

  On the other hand, when a detection unit having a mechanical mechanism is used as a position detection method of the optical pickup, a projection is formed on the optical pickup, and the detection unit is provided on the main substrate of the optical disc apparatus. Then, when the optical pickup approaches the inner periphery, the projection provided on the optical pickup comes into contact with the detection unit to detect the position of the optical pickup. However, when using a detection unit having such a mechanical mechanism, there is a problem that it is easily broken because it involves physical contact.

  Further, as in Patent Document 1 and Patent Document 2 described above, when the position of the optical pickup is detected using a photo interrupter, in order to shield the light output from the light emitting element, the reflectance is reduced on the detected side. It is necessary to provide a low shielding plate and the like, and there is a problem that the number of parts increases in the manufacture of the optical disc apparatus, and the number of steps in the manufacturing process increases.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to easily detect the position of the optical pickup device, and to reduce the weight and thickness. Another object of the present invention is to provide a new and improved optical disk apparatus.

  In order to solve the above problems, according to an aspect of the present invention, there is provided an optical pickup device that reproduces or records information on an optical disc that is an information recording / reproducing medium, a spindle motor that rotationally drives the optical disc, and an optical pickup device. A pickup driving device that moves to the inner and outer circumferences of the optical disc, a light emitting element that emits light toward the spindle motor, and a light receiving element that receives the light emitted from the light emitting element and reflected by the spindle motor. A detection unit provided in the pickup device, and a determination unit that detects the distance between the optical pickup device and the spindle motor based on the output of the detection unit and determines the position of the optical pickup device. An optical disc device is provided.

  With this configuration, the optical pickup device reproduces or records information on an optical disc that is an information recording / reproducing medium, the spindle motor rotates the optical disc, and the pickup driving device moves the optical pickup device to the inner and outer circumferences of the optical disc. Let In the detection unit, the light emitting element emits light toward the spindle motor, and the light receiving element receives the light reflected by the spindle motor. The determination unit detects the distance between the optical pickup device and the spindle motor, and determines the position of the optical pickup device.

  The determination unit may digitally determine whether or not the optical pickup device and the spindle motor are close to each other based on whether or not the output from the detection unit exceeds a predetermined threshold.

  When it is determined that the distance between the optical pickup device and the spindle motor is within a predetermined value, the determination unit determines whether the output from the detection unit has reached a predetermined threshold. The distance between the pickup device and the spindle motor may be determined in an analog manner.

  According to the present invention, the position of the optical pickup device can be easily detected, and the weight and thickness can be reduced.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

  First, the configuration of the optical disc apparatus according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing a notebook personal computer equipped with an optical disk device according to the first embodiment of the present invention. FIG. 2 is an exploded perspective view showing the optical disc apparatus according to the present embodiment. FIG. 3 is a plan view showing the optical pickup device according to the present embodiment.

  An optical disk device 1 is a device for recording and / or reproducing information on an optical disk which is an information recording / reproducing medium such as a CD (compact disc), a DVD (digital versatile disc), etc. As shown in FIG. Installed in 2nd class equipment. As shown in FIG. 2, the optical disc apparatus 1 includes a disc tray 6 that accommodates an optical disc 4 for recording / reproducing information, a housing 8 that supports the disc tray 6 so as to be able to enter and exit, and a reproduction of information recorded on the optical disc 4. And an optical pickup unit 10 for recording information on the optical disc 4. Below, each component of the optical disk apparatus 1 is demonstrated.

  The disk tray 6 includes a storage recess 12 that stores the optical disk 4, an opening 14 formed in the storage recess 12, and guide protrusions 16 formed on the side of the disk tray 6. The storage recess 12 is a substantially circular recess that is recessed from the main surface 6 b of the disc tray 6. The opening 14 is formed from the approximate center of the storage recess 12 to the front surface 6a side of the disc tray. The opening 14 exposes the disk table 54 and the objective lens 56 on the main surface 6b side of the disk tray 6 on which the optical disk 4 is installed. The guide protrusion 16 is formed in a groove shape on the side of the disk tray 6 from the front surface 6a to the back surface 6d of the disk tray.

  As described above, a substantially circular storage recess 12 is formed on the main surface 6 b of the disc tray 6, and a storage portion (not shown) for storing the optical pickup unit 10 is provided on the back side of the disc tray 6. It is formed. The storage portion is provided with a plurality of engaging protrusions (not shown). The engagement protrusion has a substantially cylindrical shape, and is engaged with a plurality of engagement holes (not shown) provided in the base chassis of the optical pickup unit 10. The disc tray 6 and the optical pickup unit 10 are connected by engaging the engaging protrusion of the storage portion and the engaging hole of the optical pickup unit 10.

  The housing 8 includes a main body portion 8b that holds the disc tray 6 in a removable manner, and a cover portion 8a that covers the main body portion 8b. The housing 8 is formed by combining the cover portion 8a and the main body portion 8b. One end side of the main body 8b of the housing 8 is opened, and a back wall 28a is formed on the other end facing the opened one end. Further, side walls 28b and 28c are formed at the edge portion connecting the open end side and the back wall 28a.

  Guide rails 30 are disposed on the side walls 28b and 28c. The guide rail 30 has a substantially U-shaped cross section from the back wall 28a to the open end side. The guide rail 30 is disposed with the U-shaped recess 30 a facing the inside of the housing 8. A guide member 20 is engaged with the guide rail 30 so as to be slidable. The guide member 20 is engaged by sandwiching the side portion of the disc tray 6. A stopper piece 22 is formed on the guide rail 30. The stopper piece 22 restricts the sliding area of the guide member 20 and prevents the disc tray 6 from being pulled out of the housing 8 beyond a predetermined length.

  An engaging convex portion 36 is provided on the main body portion 8 b of the housing 8. The engaging convex portion 36 is formed in a substantially cylindrical shape, and is engaged with a disc tray holding mechanism (not shown) that holds the disc tray 6 inside the housing 8. Moreover, the wiring board 34 is provided in the main-body part 8b so that the back wall 28a and the side wall 28b may be contact | connected. On the wiring board 34, a drive circuit is formed, and an electronic component such as a connector for connecting to an external device is mounted. An FPC (flexible printed circuit) 38 connected to the optical pickup unit 10 is attached to the wiring board 34.

  As described above, the optical pickup unit 10 is provided in the storage portion on the back side of the disc tray 6. The optical pickup unit 10 is sandwiched between a cover member 50 that covers the upper surface side of the optical pickup unit 10 and a bottom plate 52 that covers the lower surface side.

  As shown in FIG. 3, the optical pickup unit 10 includes a base chassis 60 that constitutes a unit body, a disk table 54 that is formed integrally with the base chassis 60 and on which the optical disk 4 is placed, and a disk table 54. An optical pickup device 70 that records or reproduces information signals on the optical disc 4 placed thereon, a pickup drive device 90 that moves the optical pickup device 70 in the radial direction of the optical disc 4, and a pickup drive device 90 of the optical pickup device 70. A pair of guide shafts 82 and 83 for guiding the movement of the optical axis, and the relative inclination between the objective lens 56 provided in the optical pickup device 70 and the signal recording surface of the optical disc 4 by adjusting the inclination of the guide shafts 82 and 83. And a skew adjusting mechanism 84 for adjusting.

  As shown in FIG. 3, the base chassis 60 is connected to a wiring board 35 on which a drive circuit is formed. The wiring board 35 is a so-called rigid board. A wiring pattern is formed, and various electronic components such as a connector 37 connected to an FPC 38 attached to the wiring board 34 disposed in the main body 8b of the housing 8 are provided. Is implemented.

  The base chassis 60 has an iron frame 62, and the frame 62 is formed in a rectangular shape. An opening 64 is formed in the frame 62 in a substantially rectangular shape, and the objective lens 56 of the optical pickup device 70 is formed from the opening 64 so as to be exposed on the reproduction recording surface side of the optical disc 4. In the opening 64, a pickup driving device 90 that moves the optical pickup device 70 in the longitudinal direction, a pair of guide shafts 82 and 83, and an optical pickup device 70 supported by the guide shafts 82 and 83 are disposed. The opening 64 is formed with a substantially arc-shaped notch 67 on one end side in the longitudinal direction. Inside the arc of the notch 67, a circular disc table 54 on which the optical disc 4 is placed and a disc table A spindle motor 40 that rotationally drives 54 is disposed. The spindle motor 40 is disposed below the disk table 54 and has a cylindrical shape.

  An optical pickup device 70 that records or reproduces an information signal with respect to the optical disc 4 placed on the disc table 54 includes a pickup base 74 having a substantially rectangular casing. The pickup base 74 includes at least a light source (not shown) such as a semiconductor laser, an objective lens 56 that converges and irradiates a light beam emitted from the light source on the signal recording surface of the optical disc 4, and a recording surface of the optical disc 4. The distance between the optical pickup device 70 and the spindle motor 40 is determined by a photodetector (not shown) that detects return light reflected from the optical pickup 4, a drive system that drives the objective lens 56 in the focusing direction and tracking direction of the optical disk 4. A reflective sensor 100 for detection is provided.

  Further, in the optical pickup device 70, an insertion hole 76 through which a guide shaft 82 (described later) is inserted is formed on one end side 72a in the longitudinal direction of the pickup base 74, and the other end 72b is engaged with a guide shaft 83 (described later). A joining piece 78 is formed. Connected to the pickup base 74 is a flexible wiring board (not shown) on which a drive circuit for controlling the drive system of the objective lens 56 is formed. In the optical pickup device 70, a lead screw is formed in the pickup driving device 90 that moves the pickup base 74, and an engaging member 80 that is engaged with the lead screw is formed adjacent to the guide shaft 82.

  The pair of guide shafts 82 and 83 that guide the movement of the optical pickup device 70 are disposed opposite to each other in the opening 64 of the base chassis 60. The optical pickup device 70 is guided to the inner and outer circumferences of the optical disc 4 by being supported by a pair of guide shafts 82 and 83. Both ends of the guide shafts 82 and 83 are thinner than the body portion, for example, about 1.2 mm, and both ends are supported by the skew adjusting mechanism 84. The inclinations of the guide shafts 82 and 83 are adjusted by the skew adjusting mechanism 84. As shown in FIG. 3, the skew adjusting mechanism 84 is provided at four locations corresponding to both end portions of the pair of guide shafts 82 and 83.

  Next, the reflective sensor 100 according to the present embodiment will be described with reference to FIGS. 3 and 4. FIG. 4A is a perspective view showing the reflective sensor 100 according to this embodiment. The reflective sensor 100 that detects the distance between the optical pickup device 70 and the spindle motor 40 is installed on the pickup base 74. As shown in FIG. 4A, the reflective sensor 100 has a light receiving surface 102 including a light receiving element and a light emitting surface 104 including a light emitting element. The reflective sensor 100 is installed so that the light receiving surface 102 and the light emitting surface 104 face the side surface of the spindle motor 40 when the optical pickup device 70 moves to the innermost peripheral position of the optical disc 4. Since the side surface of the spindle motor 40 is often made of metal, the light from the light emitting surface 104 is reliably reflected by the side surface of the spindle motor 40. The reflective sensor 100 is installed on the end portion 72b side of the pickup base 74, for example, as shown in FIG. FIG. 4B is a characteristic diagram showing the relationship between the distance between the reflective sensor 100 and the side surface of the spindle motor and the output of the reflective sensor 100. FIG. 4B will be described later.

  Next, control of the optical disc device 1 according to the present embodiment will be described with reference to FIG. FIG. 5 is a block diagram showing a configuration of the optical disc apparatus according to the present embodiment. The spindle motor 40 rotationally drives a disk table 54 (see FIG. 3) on which the optical disk 4 is placed. The spindle motor 40 is driven by a spindle motor driver 42.

  The optical pickup device 70 that reproduces information recorded on the optical disc 4 and records information on the optical disc 4 has the objective lens 56 as described above. The objective lens 56 is driven by the biaxial driver or the triaxial driver 114. Driven. The biaxial driver or the triaxial driver 114 is a driving device for causing the objective lens 56 to follow the optical disk 4 that rotates at high speed. The biaxial driver can drive the objective lens in the biaxial direction of the focus direction and the tracking direction, and the triaxial driver drives the objective lens in the triaxial direction of the focus direction, the tracking direction, and the radial tilt direction. Is possible. In this embodiment, either a 2-axis driver or a 3-axis driver can be applied. The laser driver 116 generates a laser drive signal that drives the laser light source of the optical pickup device 70.

  The RF amplifier 130 amplifies the signal output from the optical pickup device 70 that has read the reflected light of the laser light, and outputs the amplified signal to the signal processing unit 112 and the control unit 110. A tracking king error signal and a focus error signal are generated from the output of the RF amplifier 130, and tracking servo and focusing servo are performed. Further, a spindle motor drive signal is generated from the output signal of the RF amplifier 130, and the spindle motor 40 is rotated at a predetermined speed.

  The control unit 110 performs input / output of signals with the external interface 120, and receives the signal output from the RF amplifier 130. Then, control is performed to drive the spindle motor driver 42, the laser driver 116, and the 2-axis / 3-axis driver 114 described above.

  The optical pickup device 70 is provided with a reflective sensor 100. When the optical pickup device 70 moves to the innermost peripheral position of the optical disc 4, the reflective sensor 100 and the side surface of the spindle motor 40 face each other. Then, the light emitting element of the reflective sensor 100 emits light toward the side surface of the spindle motor 40, and the light receiving element of the reflective sensor 100 receives the reflected light reflected from the side surface of the spindle motor. The positional relationship between the pickup device 70 and the spindle motor 40 is detected. Then, the reflective sensor 100 outputs a signal 106 related to the positional relationship to the control unit 110. The control unit 110 determines whether the optical pickup device 70 and the reflective sensor 100 are close to each other according to the output from the reflective sensor 100. Then, according to the determination, control is performed to drive the spindle motor driver 42, the laser driver 116, and the 2-axis / 3-axis driver 114.

  Next, with reference to FIGS. 6 to 10, the operation of the optical disc apparatus according to the first embodiment of the present invention will be described. 6 to 8 are flowcharts showing a process of moving the optical pickup device according to this embodiment to the innermost circumference. 9A to 9C are plan views showing a state in which the optical pickup device according to the present embodiment has moved. 10 is a cross-sectional view taken along line II in FIG. 9A, line II-II in FIG. 9A, and line III-III in FIG. 9A.

  First, the operation of moving the optical pickup device 70 to the innermost periphery will be described with reference to FIG. First, it is determined whether to move the optical pickup device 70 to the innermost circumference (step S10). When the optical pickup device 70 is not moved to the innermost periphery, the optical pickup device 70 performs a normal operation. In the normal operation, for example, the optical pickup device 70 is moved to a position as shown in FIGS. 9A and 10A. When moving the optical pickup device 70 to the innermost circumference, it is next determined whether or not the tracking servo is disengaged (step S12). The tracking servo operation means that the laser beam is controlled so as to trace a track on the optical disk 4 (track by a pit row or a groove (groove)). If the tracking servo is not removed, a process for removing the tracking servo is performed (step S14).

  Next, the inner circumference detection mode is started in a state where the tracking servo is off (step S100). The inner circumference detection mode is a mode in which the positional relationship between the optical pickup device 70 and the spindle motor 40 is detected by the reflective sensor 100, and is started when a current starts to flow through the light emitting element of the reflective sensor 100. As described above, the power supply to the reflective sensor 100 is not always performed, but is limited to the state in which the tracking servo and the focusing servo are disconnected, so that the power consumption in the operation of the optical disc apparatus 1 can be suppressed.

  When the inner circumference detection mode is started, it is determined whether or not the optical pickup device 70 is already in the inner circumference position (step S102). That is, it is determined whether the inner circumference is detected by the reflective sensor 100. If the inner circumference has been detected, the inner circumference detection mode is terminated (step S108). The case where the inner circumference is detected means that, for example, it is detected that the optical pickup device 70 is closest to the spindle motor 40 as shown in FIGS. 9C and 10C.

  On the other hand, when the inner circumference is not detected, the pickup driving device 90 is driven to move the optical pickup device (OPU) 70 toward the inner circumference side of the optical disc 4 at a constant speed (step S104). Then, it is determined whether or not the reflective sensor 100 detects the inner circumference (step S106). If the inner circumference is not detected, the optical pickup device 70 is continuously moved to the inner circumference side of the optical disc 4 at a constant speed (step S104). When the reflective sensor 100 detects that the optical pickup device 70 has reached the innermost peripheral position by moving the optical pickup device 70 to the inner circumference side, the movement of the optical pickup device 70 is stopped, and the inner circumference The detection mode is terminated (step S108). The above operation is determined only by whether or not the inner circumference has been detected, and is digitally determined. For example, this threshold value for digital determination is assumed to be a predetermined threshold value A (see FIG. 4B).

  Next, a case where the sensor output reaches a predetermined threshold C will be described with reference to FIG. When the distance between the reflective sensor 100 and the detected portion (side surface of the spindle motor 40) is reduced, the light from the light emitting surface 104 is reflected by the side surface of the spindle motor 40 and detected by the light receiving surface 102. As shown in FIG. 4B, the output current at the time of light reception by the reflective sensor 100 has a characteristic of increasing until the current value reaches the maximum value as the distance between the reflective sensor 100 and the detected part approaches. . When the distance approaches a certain value, the current value decreases beyond the maximum value. A state in which the optical pickup device 70 is at the innermost peripheral position and the current value is maximized or just before the maximum is set as a predetermined threshold C of the sensor output. In the digital determination described with reference to FIG. 6, when the current value reaches the predetermined threshold A, it is determined that the inner circumference is detected by the reflective sensor 100. On the other hand, in the inner determination mode of analog determination, it is determined step by step how much the current value has reached the predetermined threshold C as the optical pickup device 70 approaches the spindle motor 40 to be detected. . Then, the movement of the optical pickup device 70 is performed by comparing the predetermined threshold C and the current current value to determine the distance between the optical pickup device 70 and the spindle motor 40 or by calculating the time change of the current value. Determine the speed.

  Specifically, a case where inner circumference detection is performed in an analog manner will be described with reference to FIG. First, after the inner circumference detection mode is started (step S200), it is determined whether or not the distance between the reflective sensor 100 and the spindle motor 40 that is the detected portion is a predetermined value or more (step S202). If this distance is less than the predetermined value, it is determined whether or not the output of the reflective sensor 100 has started to reach the predetermined threshold B (step S206). On the other hand, if the distance between the reflective sensor 100 and the spindle motor 40 is equal to or greater than a predetermined value, the pickup driving device 90 is driven to move the optical pickup device 70 toward the inner circumference side of the optical disc at a constant speed (step). S204). Then, it is determined whether or not the output of the reflective sensor 100 has started to reach a predetermined threshold value B (step S206). The output of the reflective sensor 100 starts to reach a predetermined threshold B when the distance between the reflective sensor 100 and the spindle motor 40 approaches within a predetermined value as shown in FIGS. 9B and 10B, for example.

  If the output of the reflective sensor 100 does not begin to reach the predetermined threshold value B, the pickup driving device 90 is continuously driven to move the optical pickup device 70 to the inner peripheral side at a constant speed (step S204). Then, it is continuously determined whether the sensor output has started to reach a predetermined threshold B (step S206). When the sensor output starts to reach the predetermined threshold B, the distance between the reflective sensor 100 and the spindle motor 40 approaches within a predetermined value as shown in FIGS. 9B and 10B. The speed at which the device 70 is moved is reduced (step S208). Rather than suddenly stopping the movement of the optical pickup device 70, the optical pickup device 70 that has been moving at a constant speed is moved slowly, thereby accurately moving the optical pickup device 70 to the innermost circumferential position of the optical disc 4. be able to. Further, the optical pickup device 70 can be prevented from colliding with other members.

  Next, it is determined whether or not the sensor output has reached the predetermined threshold C while moving the optical pickup device 70 toward the inner periphery at a moderate speed (step S210). If the predetermined threshold value C has not been reached, the pickup driving device 90 is continuously driven to move the optical pickup device 70 to the inner peripheral side while determining the distance between the optical pickup device 70 and the spindle motor 40 ( Step S212). Then, it is further determined whether or not the sensor output has reached a predetermined threshold value C (step S210). When the sensor output reaches the predetermined threshold C, it is the time when the optical pickup device 70 is located at the innermost circumference, so the movement of the optical pickup device 70 is stopped and the inner circumference detection mode is terminated. (Step S214).

  Next, a case where digital judgment and analog judgment are mixed for inner circumference detection will be described with reference to FIG. When the inner circumference detection mode is started (step S300), it is determined whether or not the optical pickup device 70 is already in the inner circumference position (step S302). That is, it is determined whether the inner circumference is detected by the reflective sensor 100. If the inner circumference is detected, the inner circumference detection mode is terminated. On the other hand, if the inner circumference is not detected, the pickup driving device 90 is driven to move the optical pickup device 70 to the inner circumference side of the optical disc 4 at a constant speed (step S304). Then, it is determined whether or not the reflective sensor 100 detects the inner circumference (step S306). If the inner circumference is not detected, the optical pickup device 70 is continuously moved at a constant speed on the inner circumference side of the optical disc 4. (Step S304).

  If it is determined in step S306 that the inner circumference has been detected, and the inner circumference detection mode is terminated as it is, only the digital judgment has been made for inner circumference detection. Therefore, the inner circumference can be detected with higher accuracy by making an analog determination after the inner circumference is detected. That is, when the inner circumference is detected, the pickup driving device 90 is driven to reduce the speed at which the optical pickup device 70 is moved to the inner circumference side (step S308).

  Next, it is determined whether or not the output of the reflective sensor 100 has reached the predetermined threshold C while moving the optical pickup device 70 toward the inner periphery at a moderate speed (step S310). If the predetermined threshold C has not been reached, the pickup driving device 90 is continuously driven to move the optical pickup device 70 to the inner peripheral side while determining the distance between the optical pickup device 70 and the spindle motor 40 ( Step S312), it is determined whether or not the sensor output has reached a predetermined threshold value C (Step S310). When the sensor output reaches the predetermined threshold C, it is the time when the optical pickup device 70 is located at the innermost circumference, so the movement of the optical pickup device 70 is stopped and the inner circumference detection mode is terminated. (Step S314).

  In the process shown in FIG. 8, whether or not the inner circumference has been detected as an operation before entering the stage shown in the enclosure A, that is, before the movement speed of the optical pickup device 70 (OPU) is reduced (step S308). Digital judgment is made. As a result, it is possible to determine whether or not the optical pickup device 70 has reached the vicinity of the innermost circumference earlier than the case where the determination is made only by analog determination. The inner circumference is detected with higher accuracy by further making an analog judgment after the inner circumference is detected.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this example. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

1 is a perspective view showing a notebook personal computer equipped with an optical disk device according to a first embodiment of the present invention. It is a disassembled perspective view which shows the optical disk apparatus based on the embodiment. It is a top view which shows the optical pick-up apparatus concerning the embodiment. (A) is a perspective view which shows the reflection type sensor which concerns on this embodiment. (B) is the schematic of the graph which shows the relationship between the distance of the to-be-detected object of a reflective sensor, and an electric current value. It is a block diagram which shows the structure of the optical disk apparatus based on the embodiment. 6 is a flowchart showing a process of moving the optical pickup device according to the embodiment to the innermost periphery. 6 is a flowchart showing a process of moving the optical pickup device according to the embodiment to the innermost periphery. 6 is a flowchart showing a process of moving the optical pickup device according to the embodiment to the innermost periphery. It is a top view which shows the state which the optical pick-up apparatus concerning the embodiment moved. It is a top view which shows the state which the optical pick-up apparatus concerning the embodiment moved. It is a top view which shows the state which the optical pick-up apparatus concerning the embodiment moved. (A) is sectional drawing cut | disconnected by the II line | wire of FIG. 9A. (B) is sectional drawing cut | disconnected by the II-II line | wire of FIG. 9B. (C) is sectional drawing cut | disconnected by the III-III line | wire of FIG. 9C.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk apparatus 4 Optical disk 6 Disk tray 8 Case 10 Optical pick-up unit 40 Spindle motor 54 Disc table 56 Objective lens 70 Optical pick-up apparatus 74 Pickup base 82, 83 Guide shaft 90 Pickup drive apparatus 100 Reflective sensor

Claims (3)

An optical pickup device for reproducing or recording information on an optical disc as an information recording / reproducing medium;
A spindle motor that rotationally drives the optical disc;
A pickup driving device for moving the optical pickup device to the inner and outer circumferences of the optical disc;
A light-emitting element that emits light toward the spindle motor; and a light-receiving element that receives the light emitted from the light-emitting element and reflected by the spindle motor, and is provided in the optical pickup device. When;
A determination unit that detects a distance between the optical pickup device and the spindle motor based on an output of the detection unit and determines a position of the optical pickup device;
An optical disc apparatus comprising:   The determination unit digitally determines whether or not the optical pickup device and the spindle motor are close to each other based on whether or not an output from the detection unit exceeds a predetermined threshold value. The optical disc apparatus according to claim 1. When the determination unit determines that the distance between the optical pickup device and the spindle motor is within a predetermined value, it is based on whether the output from the detection unit has reached a predetermined threshold value. 3. The optical disk apparatus according to claim 2, wherein the distance between the optical pickup device and the spindle motor is determined in an analog manner.

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