JP3870130B2 - Optical disc apparatus and optical disc rotation control method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical disc apparatus for reproducing data recorded on a track of an optical disc or recording data on the track, and an optical disc rotation control method applied to the optical disc apparatus.
[0002]
[Prior art]
Data recorded on the optical disc track by moving the optical spot spirally from the inside to the outside or from the outside to the inside with the optical spot formed on the optical disc by the optical pickup device. In an optical disc apparatus that reproduces or records data on the same track, the circumferential relative velocity (ie, linear velocity) of the optical spot with respect to the optical disc is made constant regardless of the radial position of the optical spot on the optical disc. Yes.
[0003]
In order to achieve a constant linear velocity of the light spot, generally, the wobble signal or pit signal recorded on the optical disk is reproduced, and the rotation speed of the spindle motor, that is, the optical disk, so that the reproduction signal becomes a predetermined frequency. Is controlling. However, if the above method cannot be adopted because the wobble signal or pit signal is not recorded on the optical disk, the radial relative position of the light spot on the optical disk (that is, the radius of the light spot formation position) is detected. Based on the detected radius, the rotation speed of the spindle motor is calculated so that the linear velocity of the light spot on the optical disk is always constant, and the spindle motor rotates at the calculated rotation speed. The rotation of the motor is controlled.
[0004]
In this type of optical disk apparatus, a track actuator provided in the optical pickup apparatus for minutely displacing the objective lens in the radial direction of the optical disk is driven and controlled using a control signal (track servo signal) based on the track error signal. Thus, in addition to track servo control for controlling the light spot to follow the track of the optical disk, thread servo control is performed. In this thread servo control, a moving device such as an optical motor for moving an optical pickup device or a spindle motor is driven and controlled using a DC component of a track servo signal (more precisely, a DC component including an AC component having a large frequency). Thus, the optical spot is displaced in the radial direction over a wide range with respect to the optical disc, and the objective lens is always changed in the radial direction of the optical disc in the vicinity of the neutral position.
[0005]
However, the displacement of the light spot by the sled servo control advances from the radially inner side to the outer side or from the radially outer side to the inner side with a slight fluctuation due to the eccentricity of the optical disk. Accordingly, the radius of the formation position of the light spot used for the rotation control of the spindle motor also fluctuates slightly. As a result, the rotation speed of the spindle motor (optical disc) also decreases or increases while fluctuating slightly. Conventionally, this has been dealt with by ignoring minute fluctuations in the rotational speed of the spindle motor (optical disk) or by increasing the resolution of the rotational speed of the spindle motor.
[0006]
[Problems to be solved by the invention]
However, conventional methods are not an essential solution. In other words, ignoring minute fluctuations in the optical disk or coarsening the resolution of the rotation speed of the spindle motor deteriorates the jitter of the reproduction signal of the optical disk, and the spindle motor cannot be rotationally controlled with high accuracy. There is a problem that accurate recording and reproduction cannot be performed. In particular, it becomes a problem when the recording density of data on the optical disc is increased or the rotational speed of the optical disc is increased.
[0007]
SUMMARY OF THE INVENTION
The present invention has been made to cope with the above-mentioned problems, and its object is to improve the jitter of the reproduction signal of the optical disk and to control the rotation of the spindle motor with high precision so that high-precision recording on the optical disk is possible. An object of the present invention is to provide an optical disc apparatus that realizes reproduction and an optical disc rotation control method.
[0008]
In order to achieve the above object, the constitutional feature of the present invention is that an optical pickup device that forms a light spot by a laser beam on the optical disc and receives reflected light from the light spot, a spindle motor that rotates the optical disc, and Spindle motor that inputs rotational speed data representing the rotational speed of the spindle motor and controls the spindle motor according to the input rotational speed data to rotate the spindle motor at the rotational speed represented by the rotational speed data. A rotation control circuit and a moving device that drives an optical pickup device or a spindle motor to move the light spot relative to the optical disk in the radial direction, and reproduces data recorded on the track of the optical disk or data on the track Optical disk device or the same optical disk In the rotation control method of the optical disc applied to the apparatus, the radial relative position of the optical spot with respect to the optical disc by relative movement of the moving device is detected, and the circumferential relative of the optical spot with respect to the optical disc is detected based on the detected radial relative position. The spindle motor target rotational speed is repeatedly calculated so that the speed is constant, and the smaller of the rotational speed represented by the rotational speed data that was previously output to the spindle motor rotational control circuit and the calculated target rotational speed. Rotation speed data representing the selected rotation speed is repeatedly selected depending on whether the track on the optical disk is wound from the inside to the outside or from the outside to the inside. Is repeatedly output to the spindle motor rotation control circuit.
[0009]
In the present invention configured as described above, the rotation speed represented by the rotation speed data output to the spindle motor rotation control circuit last time, the target rotation speed calculated based on the radial relative position of the light spot with respect to the optical disc, Among them, the rotational speed data representing the smaller rotational speed or the larger rotational speed selected depending on whether the track on the optical disk is wound from the inside to the outside or from the outside to the inside, In order to control the rotation speed of the spindle motor, it is output to the spindle motor rotation control circuit. More specifically, when a track on the optical disk is wound from the inside to the outside (in the case of a forward spiral), rotation speed data representing the smaller rotation speed is output to the spindle motor rotation control circuit. The Further, when the track on the optical disk is wound from the outside to the inside (that is, in the case of the reverse spiral), the rotation speed data representing the larger rotation speed is output to the spindle motor rotation control circuit.
[0010]
In this case, since the rotation speed represented by the rotation speed data output to the spindle motor rotation control circuit last time represents the current rotation speed of the spindle motor, it is based on the radial relative position of the light spot with respect to the spindle motor. Even if the calculated target rotational speed of the spindle motor (optical disk) varies, fluctuations in the rotational speed of the spindle motor (optical disk) can be suppressed. In addition, when the track on the optical disc is a forward spiral, rotation speed data representing the smaller rotation speed can be output to the spindle motor rotation control circuit. In addition, when the track on the optical disk is a reverse spiral, rotation speed data representing the larger rotation speed can be output to the spindle motor rotation control circuit. The selection of the smaller or larger rotational speed corresponds to the direction of change of the rotational speed of the optical disk for constant linear speed control. Therefore, the rotational speed output to the spindle motor rotation control circuit is The rotational speed of the optical disk calculated according to the radial relative position of the light spot with respect to is accurately expressed. As a result, according to the present invention, the jitter of the reproduction signal of the optical disk becomes good, and the spindle motor can be controlled to rotate with high precision, so that high-precision recording / reproduction with respect to the optical disk can be realized. become.
[0011]
In selecting the smaller rotational speed or the larger rotational speed, if the optical disk recorded and reproduced by the optical disk apparatus according to the present invention is only a forward spiral, the smaller rotational speed is selected in the selection. May be set in advance so that is always selected. On the contrary, if the optical disk to be recorded and reproduced by the optical disk apparatus according to the present invention is only a reverse spiral, it may be set in advance so that the larger rotational speed is always selected in the selection. On the other hand, when the optical disc recorded and reproduced by the optical disc apparatus according to the present invention has both the forward spiral and the reverse spiral, the smaller rotational speed or the larger rotational speed is selected before recording and reproduction. Just do it.
[0012]
[Embodiment]
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram schematically showing an optical disk inspection apparatus for inspecting an optical disk DK such as a CD or a DVD by applying the optical disk apparatus and the optical disk rotation control method according to the present invention.
[0013]
The optical disk DK inspection device includes an optical pickup device 10. The optical pickup device 10 includes a laser light source 11, a collimating lens 12, a polarization beam splitter 13, a quarter wavelength plate 14, an objective lens 15, a cylindrical lens 16, and a photodetector 17.
[0014]
In this optical pickup device 10, the optical disk DK is irradiated with the laser light from the laser light source 11 via the collimating lens 12, the polarization beam splitter 13, the quarter wavelength plate 14 and the objective lens 15. A light spot is formed on the DK. The reflected light from the light spot formed on the optical disk DK is guided to the photodetector 17 through the objective lens 15, the quarter wavelength plate 14, the polarization beam splitter 13, and the cylindrical lens 16, and is received. The photodetector 17 is composed of four divided light receiving elements that are four identical square light receiving elements divided by a dividing line, and outputs a voltage signal proportional to the amount of laser light received by each divided light receiving element.
[0015]
The optical pickup device 10 also includes a track actuator 18. The track actuator 18 displaces the objective lens 15 in the radial direction of the optical disc DK in accordance with the track servo signal to cause the objective lens 15 to follow the track. The optical pickup device 10 also includes a focus actuator that displaces the objective lens 15 in the optical axis direction for focus servo control. However, since this focus actuator is not directly related to the present invention, the explanation will be simplified. Therefore, the description is omitted in this specification.
[0016]
Such an inspection apparatus includes a spindle motor 21 having a built-in encoder 21a. The spindle motor 21 rotationally drives the turntable 22 on which the optical disk DK is assembled. The encoder 21a detects the rotation of the spindle motor 21, that is, the rotation of the turntable 22 (optical disk DK), and outputs a rotation detection signal indicating the rotation. This rotation detection signal is based on a reference signal φo generated every time the rotation position of the turntable 22 (optical disk DK) reaches the reference rotation position, and a pulse train signal that repeats a high level and a low level by a predetermined minute rotation angle. Rotation signal φ _A , Φ _B It consists of. These rotation signals φ _A , Φ _B Are shifted from each other by π / 2.
[0017]
These rotation detection signals φo, φ _A , Φ _B Is supplied to the spindle motor rotation control circuit 23. The spindle motor rotation control circuit 23 generates rotation detection signals φo, φ _A , Φ _B The linear velocity of the optical disk DK at the laser irradiation position (corresponding to the relative speed in the circumferential direction of the light spot on the optical disk DK) is a standardized constant value using data representing the rotational speed SP input from the computer device 30. Thus, the spindle motor 21 is rotated. The spindle motor rotation control circuit 23 has rotation detection signals φo and φ _A , Φ _B Based on the above, a rotation speed detection circuit for detecting the actual rotation speed of the spindle motor 21 is also incorporated.
[0018]
The spindle motor 21 is driven in the radial direction of the optical disk DK by a feed mechanism. The feed mechanism includes a support plate 24, a feed motor 25 and a screw rod 26. The support plate 24 fixes the spindle motor 21 and the like, and only the radial movement of the optical disk DK is allowed. The feed motor 25 rotates the screw rod 26 around its axis by the rotation. The screw rod 26 is screwed into a nut 27 fixed to the support plate 24, and the support plate 24 is moved together with the spindle motor 21 in the radial direction of the optical disk DK by the rotation thereof.
[0019]
In the feed motor 25, an encoder 25a configured similarly to the encoder 21a of the spindle motor 21 is incorporated. The encoder 25a repeats a reference signal φo generated every time the rotation position of the screw rod 26 reaches the reference rotation position, and a high level and a low level by a predetermined minute rotation angle, and is shifted in phase by π / 2. Rotation signal φ consisting of a pulse train signal _A , Φ _B A rotation detection signal consisting of
[0020]
The rotation detection signals φo, φ detected by the encoder 25a _A , Φ _B Is supplied to the radial position detection circuit 28. The radial position detection circuit 28 has rotation detection signals φo, φ from the encoder 25a. _A , Φ _B Thus, the radial position (that is, the radius) of the optical spot formed by the optical pickup device 10 with respect to the optical disc DK is detected, and the radial position data representing the same radial direction position is output to the computer device 30.
[0021]
If a little explanation is added about the detection of the radial direction position, the state in which the support plate 24, the spindle motor 21 and the optical disk DK are in a predetermined reference position with respect to the optical pickup device 10 is referred to as a reference rotation position of the screw rod 26. Then, the position of the support plate 24, the spindle motor 21 and the optical disk DK with respect to the optical pickup device 10 (distance from the reference position) is proportional to the rotation angle of the screw rod 26 from the reference rotation position, and the proportionality constant is the screw. This constant is determined by the pitch of the rod 26 and the nut 27. Further, since the light spot formed by the optical pickup device 10 is stationary, the radial position of the support plate 24, the spindle motor 21 and the optical disk DK with respect to the optical pickup device 10 is the relative position of the light spot to the optical disk DK. It will also represent. Then, if the relative position of the light spot with respect to the optical disk DK is converted into the distance from the center position of the optical disk DK, the radial position of the light spot with respect to the optical disk DK is calculated.
[0022]
The computer device 30 includes a CPU, ROM, RAM, hard disk, and the like, and controls the rotation speed of the spindle motor 21 based on the radial position data from the radial position detection circuit 28 by executing the rotation control program of FIG. . This rotation control program is supplied from the outside and stored in the RAM or hard disk, or stored in advance in the ROM.
[0023]
Further, the inspection apparatus uses a track error signal generated by the track error signal generation circuit 41 to perform a track servo control of the track actuator 18 and a thread servo control (feed servo control) of the feed motor 25. A sled servo circuit 43 (feed servo control circuit 43). The track error signal generation circuit 41 generates and outputs a track error signal indicating the radial deviation amount of the light spot from the track on the optical disk DK based on the light reception signal from the photodetector 17.
[0024]
The track servo circuit 42 controls the track actuator 18 via the drive circuit 44 in accordance with a control signal (track servo signal) based on the track error signal and displaces the objective lens 15 in the radial direction, so that the light spot is changed. Try to follow the track. The sled servo circuit 43 extracts a component that is included in the track servo signal and changes in a DC manner (more precisely, a DC component that includes an alternating current component having a large frequency), that is, a sled servo control signal, and supplies it to the feed motor rotation control circuit 45. Output. The feed motor rotation control circuit 45 controls the rotation of the feed motor 25 using the sled servo control signal so that the light spot follows the track. In this case, the track servo control shares track following in a minute range of the light spot, and the thread servo control performs a large range of the light spot from the inner diameter to the outer diameter (or from the outer diameter to the inner diameter) of the recording phase of the optical disc DK. The optical spot functions in such a manner that the objective lens 15 always varies in the radial direction of the optical disc DK in the vicinity of the neutral position.
[0025]
The inspection apparatus also includes a sum signal generation circuit 51, a binarization circuit 52, and a reproduction signal evaluation apparatus 53. The sum signal generation circuit 51 is connected to the photo detector 17 and generates a sum signal using the light reception signal from the photo detector 17. A binarization circuit 52 binarizes the sum signal. The reproduction signal evaluation device 53 evaluates the reproduction signal reproduced by the optical pickup device 10 using the binarized sum signal. The evaluation of the reproduction signal includes, for example, jitter measurement.
[0026]
The operation of the embodiment configured as described above will be described. First, the inspector attaches the optical disc DK to be inspected to the turntable 22 and instructs the start of the operation of the inspection apparatus according to the embodiment. In response to this operation start instruction, the optical pickup device 10 forms a light spot by the laser light on the optical disc DK and receives reflected light by the light spot by the photodetector 17. The spindle motor 21 starts rotation and rotates the optical disk DK on the turntable 22 at a rotational speed that makes the linear speed constant under the control of the computer device 30 described in detail later. The feed motor 25 also starts to rotate, and the spindle motor 21, the support plate 24, the turntable 22 and the optical disk DK are moved from the initial position to the left or right in the figure via a screw mechanism including a screw rod 26 and a nut 27. Let
[0027]
In this case, if the track of the optical disk DK is spirally wound from the inside to the outside, that is, if the track of the optical disk DK is a forward spiral, the initial position is that the light spot by the laser beam is in the radial direction of the optical disk DK. In this case, the optical disk DK or the like moves in the left direction in the figure by the rotation of the feed motor 25. On the other hand, if the track of the optical disk DK is spirally wound from the outside to the inside, that is, if the track of the optical disk DK is a spiral in the reverse direction, the light spot by the laser beam is in the radial direction of the optical disk DK. The position is set so as to be formed at the outermost peripheral position. In this case, the optical disk DK or the like moves in the right direction in the figure by the rotation of the feed motor 25.
[0028]
Whether the track of the optical disc DK is a forward spiral or a reverse spiral is determined by an operator operating an operation switch (not shown) according to the type of the optical disc DK mounted on the turntable 22. input. Also, instead of directly inputting the direction of the spiral, a table storing data indicating whether the spiral is a forward spiral or a reverse spiral is prepared for each type of the optical disk DK in the inspection apparatus. Alternatively, when the inspector inputs the type of the optical disk DK, the inspection apparatus may automatically determine the spiral direction with reference to the table. Further, the optical disc DK itself may have an identification mark representing a forward spiral or a reverse spiral, and the inspection device may read the identification mark and automatically determine the direction of the spiral.
[0029]
While the optical disk DK rotates and moves to the left and right, the photodetector 17 in the optical pickup device 10 receives the reflected light from the light spot, and the received light signal from the received light is sent to the track error signal generation circuit 41. Supplied. The track error signal generation circuit 41 generates a track error signal based on the received light signal and outputs it to the track servo circuit 42.
[0030]
The track servo circuit 42 drives and controls the track actuator 18 via the drive circuit 44 by a control signal (track servo signal) based on the track error signal, thereby causing the objective lens 15 to be slightly displaced in the radial direction of the optical disk DK. The track servo control is performed so that the light spot follows the track of the optical disk DK.
[0031]
The track error signal is also supplied to the thread servo circuit 43 via the track servo circuit 42. The sled servo circuit 43 takes out a component that changes in a direct current (accurately, a direct current component including an alternating current component having a large frequency) included in the track servo signal, that is, a sled servo control signal, and feeds motor rotation control circuit 45. By controlling the feed motor 25 via the optical disk DK, the optical disk DK or the like is moved leftward or rightward so that the light spot has a diameter from the innermost circumference to the outermost circumference or from the outermost circumference to the innermost circumference. Displace over a wide range in the direction. Also, by this thread servo control, the objective lens 15 is always track servo controlled near the neutral position, so the accuracy of the track servo control is improved.
[0032]
On the other hand, the light reception signal from the photodetector 17 is also supplied to the sum signal generation circuit 51. This received light signal is generated into a sum signal by the sum signal generation circuit 51, and the generated sum signal is binarized by the binarization circuit 52 and supplied to the reproduction signal evaluation device 53. The reproduction signal evaluation device evaluates the reproduction signal reproduced by the optical pickup device 10 using the binarized sum signal, for example, measures the jitter of the reproduction signal. By this measurement, the optical disk DK is inspected.
[0033]
On the other hand, during the inspection of the optical disc DK, the radial position detection circuit 28 detects the rotation detection signals φo and φ from the encoder 25a in the feed motor 25. _A , Φ _B The radial position of the optical spot formed by the optical pickup device 10 with respect to the optical disk DK (ie, the radius) is detected, and the radial position data representing the same radial direction position is continuously output to the computer device 30. . The computer device 30 repeatedly executes the rotation control program of FIG. 2 every predetermined short time, and continues to control the rotation of the spindle motor 21.
[0034]
Execution of the rotation control program is started in step S10. In step S12, radial position data is input from the radial position detection circuit 28, and in step S14, the target rotational speed SPnew of the spindle motor 21 is calculated. . In the calculation of the target rotational speed SPnew, a predetermined position in which the linear velocity of the light spot at the same radial position is defined using the radial position (radius) of the optical spot on the optical disk DK represented by the radial position data. The target rotational speed SPnew of the spindle motor 21 is calculated so as to be a value (a constant value).
[0035]
Next, in step S16, the calculated target rotation speed SPnew and the processing of steps S26 and S28 described later are output to the spindle motor rotation control circuit 23 during the previous program execution and stored in the computer device 30. It is determined whether or not the absolute value | SPnew−SPold | of the difference from the old rotational speed SPold represented by the rotational speed data is equal to or smaller than a predetermined value ΔSPo. This predetermined value ΔSPo is the maximum value that may change when the radius of the light spot slightly fluctuates due to the eccentricity of the optical disc DK or the like under the track servo control and thread servo control. Is preset to a value approximately equal to.
[0036]
If the normal track servo control and sled servo control are performed, the absolute value | SPnew-SPold | is equal to or less than the predetermined value ΔSPo. Therefore, “Yes” is determined in step S16, and the process proceeds to step S18. move on. In step S18, it is determined whether the optical disk DK mounted on the turntable 22 is a forward spiral or a reverse spiral. For this determination, the spiral direction input or automatically determined by the inspector described above is used.
[0037]
If the optical disk DK is a forward spiral, “Yes” is determined in step S18, and the process proceeds to step S20. In step S20, the smaller rotational speed SP (= MIN [SPnew, SPnew, between the target rotational speed SPnew of the spindle motor 21 calculated this time and the old rotational speed SPold of the spindle motor 21 previously output is calculated. SPold]) is determined as the control rotational speed of the spindle motor 21. On the other hand, if the optical disk DK is a reverse spiral, “No” is determined in step S18, and the process proceeds to step S22. In step S22, the larger rotational speed SP (= MAX [SPnew, SPnew, among the target rotational speed SPnew of the spindle motor 21 calculated this time and the previous rotational speed SPold of the spindle motor 21 output previously is described. SPold]) is determined as the control rotational speed of the spindle motor 21.
[0038]
After the processing in steps S20 and S22, data representing the rotational speed SP determined as the control rotational speed of the spindle motor 21 by the processing in step S20 or step S22 is output to the spindle motor rotation control circuit 23 in step S26. The spindle motor rotation control circuit 23 uses the rotation detection signal from the encoder 21a provided in the spindle motor 21 to control the rotation speed of the spindle motor 21 to the rotation speed SP represented by the supplied data. Accordingly, the rotation of the optical disk DK is controlled at a constant linear velocity corresponding to the rotational speed SP.
[0039]
After the process of step S26, the rotation speed SP output to the spindle motor rotation control circuit 23 in step S28 is stored as data representing the old rotation speed SPold, and the execution of this rotation control program is terminated in step S30. Then, each time a predetermined short time elapses, the computer device 30 executes the rotation control program described above again to control the rotation of the optical disc DK. By executing such a rotation control program, as long as the absolute value | SPnew−SPold | Is controlled to rotate at a constant linear velocity using the radius of the light spot.
[0040]
In such rotation control of the spindle motor 21, the rotation speed SP represented by the data output to the spindle motor rotation control circuit 23 by the processing in step S26 at the previous program execution is the spindle motor at the time of the current program execution. Therefore, even if the target rotational speed of the spindle motor 21 (optical disk DK) calculated based on the radial relative position of the light spot with respect to the spindle motor 21 fluctuates, the spindle motor 21 (optical disk) The fluctuation in the rotational speed of (DK) can be suppressed. In addition, the selection of the smaller or larger rotational speed SP according to the spiral direction of the optical disk DK in steps S18 to S22 corresponds to the changing direction of the rotational speed of the optical disk DK for constant linear velocity control. Therefore, the rotation speed represented by the data output to the spindle motor rotation control circuit 23 accurately represents the rotation speed of the optical disc DK calculated in accordance with the radial relative position of the light spot with respect to the optical disc DK. . As a result, according to this embodiment, the jitter of the reproduction signal of the optical disc DK becomes good, and the spindle motor 21 can be controlled to rotate with high accuracy, thereby realizing high accuracy reproduction of the optical disc DK. Will be able to.
[0041]
If it is determined in step S16 that "No", that is, the absolute value | SPnew-SPold | of the difference between the target rotational speed SPnew and the old rotational speed SPold is larger than the predetermined value ΔSPo, the rotational speed is determined in step S24. SP is set to the target rotational speed SPnew calculated by the process of step 14. Then, the data representing the set rotational speed SP is output to the spindle motor rotation control circuit 23 and stored and stored as the old rotational speed SPold by the processes in steps S26 and S28 described above. Therefore, the rotation speed of the optical disk DK is controlled to the newly set rotation speed SP (equal to the target rotation speed SPnew).
[0042]
In this case, the predetermined value ΔSPo is set in advance to a value substantially equal to the maximum value at which the radius of the light spot may change under normal track servo control and sled servo control. Therefore, it is possible to cope with a case where the rotational speed of the optical disc DK increases or decreases instantaneously when the inspector intentionally changes the linear velocity or when the radial position of the light spot is changed by track jump.
[0043]
Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the object of the present invention.
[0044]
In the above embodiment, the example in which the present invention is applied to the inspection apparatus corresponding to both the forward direction and the reverse direction of the spiral in the optical disc DK has been described. However, when the present invention is applied to an inspection apparatus that inspects only the forward spiral optical disk DK, the processes of steps S18 and S22 are omitted, and the target rotational speed SPnew and the old rotational speed SPold are processed by the process of step S20. The rotation speed of the smaller one of them should always be selected. Further, when the present invention is applied to an inspection apparatus that inspects only the spiral optical disk DK, the processing of steps S18 and S20 is omitted, and the target rotational speed SPnew and the old rotational speed SPold are processed by the processing of step S22. It is sufficient that the larger one of the rotation speeds is always selected.
[0045]
In the above embodiment, the spindle motor 21, the turntable 22, and the optical disk DK are moved in the radial direction of the optical disk DK with respect to the optical pickup device 10. However, instead of this, the optical pickup device 10 may be moved in the radial direction of the optical disk DK with respect to the optical disk DK.
[0046]
Furthermore, in the above-described embodiment, the present invention is applied to the optical disk DK inspection apparatus. However, the present invention may be applied to a reproducing apparatus that simply reproduces data recorded on the optical disk DK, or data on the optical disk DK. The present invention may be applied to a recording apparatus that simply records. Further, the present invention may be applied to a recording / reproducing apparatus that enables both recording and reproduction.
[Brief description of the drawings]
FIG. 1 is a block diagram schematically showing an entire optical disk inspection apparatus according to an embodiment of the present invention.
FIG. 2 is a flowchart of a rotation control program executed by the computer apparatus of FIG.
[Explanation of symbols]
DK: optical disk, 10: optical pickup device, 11: laser light source, 15: objective lens, 17: photo detector, 18: track actuator, 21: spindle motor, 21a: encoder, 23: spindle motor rotation control circuit, 25: feed motor 25a ... encoder, 26 ... screw rod, 28 ... radial position detection circuit, 30 ... computer device, 41 ... track error signal generation circuit, 42 ... track servo circuit, 43 ... thread servo circuit, 45 ... feed motor rotation control circuit .

Claims (2)

An optical pickup device for forming a light spot by a laser beam on an optical disk and receiving reflected light from the light spot;
A spindle motor that rotates the optical disc;
Rotational speed data representing the rotational speed of the spindle motor is input, and the spindle motor is controlled in accordance with the input rotational speed data to rotate the spindle motor at the rotational speed represented by the rotational speed data. A spindle motor rotation control circuit;
A moving device that drives the optical pickup device or the spindle motor to move the optical spot in a radial direction relative to the optical disc, and reproduces data recorded on the track of the optical disc or records data on the track In the optical disk device
A radial position detecting means for detecting a radial relative position of the light spot with respect to the optical disc by relative movement of the moving device;
Target rotational speed calculation means for repeatedly calculating the target rotational speed of the spindle motor so that the circumferential relative speed of the light spot with respect to the optical disc is constant based on the detected radial relative position;
The track on the optical disc shows the smaller or greater of the rotation speed represented by the rotation speed data output to the spindle motor rotation control circuit and the calculated target rotation speed. A rotational speed selecting means for repeatedly selecting whether to wind from the outside to the outside or from the outside to the inside, and repeatedly outputting rotational speed data representing the selected rotational speed to the spindle motor rotation control circuit; An optical disc apparatus comprising: An optical pickup device for forming a light spot by a laser beam on an optical disk and receiving reflected light from the light spot;
A spindle motor that rotates the optical disc;
Rotational speed data representing the rotational speed of the spindle motor is input, and the spindle motor is controlled in accordance with the input rotational speed data to rotate the spindle motor at the rotational speed represented by the rotational speed data. A spindle motor rotation control circuit;
A moving device that drives the optical pickup device or the spindle motor to move the optical spot in a radial direction relative to the optical disc, and reproduces data recorded on the track of the optical disc or records data on the track Applied to the optical disk device
Detecting the relative position in the radial direction of the light spot with respect to the optical disc by relative movement of the moving device;
Based on the detected radial relative position, repeatedly calculate the target rotational speed of the spindle motor so that the circumferential relative speed of the light spot with respect to the optical disc is constant,
The track on the optical disc shows the smaller or greater of the rotation speed represented by the rotation speed data output to the spindle motor rotation control circuit and the calculated target rotation speed. It is selected repeatedly depending on whether it is wound from the outside to the outside or from the outside to the inside, and rotation speed data representing the selected rotation speed is repeatedly output to the spindle motor rotation control circuit. An optical disk rotation control method characterized by the following.

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