JP2016012379A - Optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk device such that the rotation speed of a motor is controlled and consumption power is reduced without depending on operation on a host controller side.SOLUTION: An optical disk device includes: data output control means that outputs a second request of causing an optical pickup to read data recorded on an optical disk and outputs data recorded in a buffer memory in response to a first request; proportion calculation means that calculates the proportion of a standby time in which the second request is not outputted in a predetermined time; and rotation control means that controls a motor driver to decrease the rotation speed of a motor.

Description

  The present invention relates to an optical disc apparatus for reproducing an optical disc, and more particularly to an optical disc apparatus capable of reducing power consumption by controlling rotation of an optical disc.

  In an optical disk device, an optical disk is rotated by a motor, and data recorded on the rotating optical disk is read by an optical pickup. In addition, the optical disc apparatus includes a drive controller that controls the optical pickup, a host controller that requests the drive controller to read data, and a buffer memory.

  The drive controller records the data read by the optical pickup in advance in the buffer memory in preparation for the data request from the host controller. When the drive controller receives a request for data from the host controller, if the requested data is recorded in the buffer memory, the drive controller outputs this data to the host controller. Therefore, the drive controller can stably output data to the host controller by storing a sufficient amount of data in the buffer memory regardless of the data request from the host controller.

  The amount of data that can be stored in the buffer memory per time is determined by the amount of data that can be read from the optical disc by the optical pickup (also described as data transfer amount and transfer rate). Since the amount of data transferred in the optical pickup is proportional to the rotation speed (rpm) of the optical disk, the higher the rotation speed of the optical disk, the larger the amount of data stored in the buffer memory per hour than when the rotation speed is low. can do.

  Cited Documents 1 and 2 disclose a technique for optimizing the rotation speed of an optical disc according to the amount of data recorded in a buffer memory (see, for example, Patent Documents 1 and 2). For example, Patent Document 1 discloses that the data volume recorded in the buffer memory is monitored by a buffer manager, and the rotation speed of the optical disk is varied when the data volume falls below a threshold value.

JP 2002-367286 A JP 2009-020977 A

  In the method of monitoring the data capacity recorded in the buffer memory in order to control the rotation speed of the optical disc, the rotation speed cannot be controlled independently on the device controller side because it depends on the state on the host controller side.

  The present invention has been made in view of the above problems, and an object of the present invention is to reduce the power consumption by controlling the rotation speed of the motor without depending on the operation on the host controller side.

・ Application example 1
In order to solve the above problems, according to one aspect of the present invention, a motor driver that drives a motor that rotates an optical disc, an optical pickup that reads data recorded on the optical disc, and data that the optical pickup reads are recorded. A buffer memory, a host controller that outputs a first request for requesting the data, a second request for causing the optical pickup to read data recorded on the optical disc, and the first request A data output control means for outputting the data recorded in the buffer memory in response, a ratio calculation means for calculating a ratio of the waiting time during which the second request occupies a predetermined time, and a calculation If the ratio is equal to or greater than a threshold value, the motor driver is given a rotational speed of the motor. Having a rotation control unit for dropping.

In the invention configured as described above, the output control means outputs a second request for causing the optical pickup to read data recorded on the optical disk into the buffer memory. The output control means outputs the data recorded in the buffer memory by the second request in response to the first request from the host controller. In addition, the ratio calculation unit calculates a ratio of the standby time during which the output control unit does not output the second request in a predetermined time. Then, the rotation control means causes the motor driver to reduce the rotation speed of the motor when the ratio calculated by the ratio calculation means is equal to or greater than the threshold value.
Therefore, the motor speed can be adjusted without monitoring the data capacity of the buffer memory in order to adjust the motor speed in accordance with the ratio of the standby time when the output control means does not make the second request. it can.

-Application example 2
In one aspect of the present invention, the ratio calculation unit acquires the waiting time by counting a period in which the second request is not generated.
In the invention configured as described above, the standby time can be obtained by a simpler method.

-Application example 3
In one aspect of the present invention, the rotation control means decreases the rotation speed of the motor stepwise in accordance with the ratio.
In the invention configured as described above, since the rotational speed is changed stepwise, it is possible to achieve a reduction in power consumption and the reproduction performance of the apparatus in a balanced manner.

Application example 4
In one aspect of the present invention, the rotation control means performs CLV rotation control, and when the optical pickup refers to an address on the inner peripheral side of the optical disc, refers to an address on the outer peripheral side of the optical disc. Compared to the case, the predetermined time is lengthened.
In the invention configured as described above, power consumption can be reduced even in CLV rotation control.

-Application example 5
In one aspect of the present invention, the rotation control means does not apply a brake voltage when the rotation speed of the motor is decreased.
In the invention configured as described above, power consumption can be reduced.

Application example 6
In one aspect of the present invention, the rotation control unit causes the motor driver to return the rotation speed of the motor to an initial value when the calculated ratio is low.
In the invention configured as described above, reduction in power consumption and reproduction performance of the apparatus can be realized in a balanced manner.

Application example 7
In one aspect of the present invention, the ratio calculation means calculates the ratio at a first time that is the predetermined time and a second time that is longer than the first time, The rotation control unit increases the rotation speed of the motor when the ratio at the first time is low, and decreases the rotation speed of the motor when the ratio at the second time is high.
In the invention configured as described above, by changing the rotation speed of the motor in accordance with the change in the transfer speed in a short time and the change in the transfer speed in a long time, it is more suitable for the data transfer speed. Power consumption can be reduced optimally.

1 is an overall configuration diagram of an information processing system including an optical disk device. FIG. 4 is a sequence diagram for explaining output control processing executed by the drive controller 30. The figure which shows the frequency which the drive controller 30 produces | generates a 2nd request | requirement, when reproducing | regenerating DVD. The figure which shows the conversion table which the rotation control means 33 refers. 6 is a flowchart for explaining rotation control executed by the drive controller 30. The flowchart explaining the process performed in FIG.5 S1. The flowchart explaining the rotation control process performed by step S2. The figure explaining CLV rotation control. The flowchart explaining the ratio calculation process which the ratio calculation means 32 performs. The figure which shows the ratio of the wait time Twait which occupies for each calculation time Tall. 5 is a flowchart for explaining processing executed by the drive controller 30.

Hereinafter, embodiments of the present invention will be described in the following order.
1. First embodiment:
(1) Configuration of optical disc apparatus (2) Motor rotation speed control method Second embodiment:
3. Third embodiment:
4). Fourth embodiment:
5. Other embodiments:

1. First embodiment:
(1) Configuration of optical disk device
FIG. 1 is an overall configuration diagram of an information processing system including an optical disk device.
The optical disc device 10 can rotate an optical disc M such as a CD, a DVD, an HD-DVD, or a BD to read data recorded on the optical disc M and write data to the optical disc M.
An optical disk apparatus 10 shown in FIG. 1 includes a spindle motor 11, a motor driver 12, an optical pickup unit 13, an RF circuit 14, an address decoding circuit 15, an encoding / decoding circuit 16, a first buffer memory 20, a second buffer memory 21, and a drive. A controller 30, a host controller 40, and a playback unit 50.

  The spindle motor 11 rotates a turntable (not shown) on which the optical disk M is set. The spindle motor 11 is driven by a motor driver 12. The motor driver 12 is servo-controlled by the drive controller 30 so that the spindle motor 11 has a desired rotational speed.

  The optical pickup unit 13 includes a laser diode (LD) for irradiating the optical disk M with laser light, a photodetector (PD) that receives reflected light from the optical disk M and converts it into an electrical signal, and a driver. Opposed. The optical pickup unit 13 is driven in the radial direction of the optical disc M by a thread motor (not shown). A driver (not shown) of the optical pickup unit 13 is servo-controlled by the drive controller 30 in the same manner as the motor driver 12.

  When reading the data recorded on the optical disk M, a laser beam of reproduction power is irradiated from the LD of the optical pickup unit 13, and the reflected light is converted into an electric signal and output. A reproduction signal from the optical pickup unit 13 is supplied to the RF circuit 14. The RF circuit 14 generates a focus error signal and a tracking error signal from the reproduction signal and supplies them to the drive controller 30. The drive controller 30 servo-controls the optical pickup unit 13 based on these error signals, and maintains the optical pickup unit 13 in an on-focus state and an on-track state. Further, the RF circuit 14 supplies an address signal included in the reproduction signal to the address decoding circuit 15. The address decoding circuit 15 demodulates the address data of the optical disc M from the address signal and supplies it to the drive controller 30 and the host controller 40. The RF circuit 14 binarizes the reproduction signal and supplies the obtained signal to the encode / decode circuit 16. The encode / decode circuit 16 demodulates the binary signal and corrects errors to obtain reproduction data, and records the reproduction data in the first buffer memory 20.

  In the first buffer memory 20, the pre-read data block is stored as cache data. If the data requested by the host controller 40 is recorded in the first buffer memory 20, the optical pickup unit 13 does not read data from the optical disk M, but only needs to read it from the first buffer memory 20. Turn into.

  The second buffer memory 21 records data used by the host controller 40 and output from the first buffer memory 20. In addition, a playback unit 50 is connected to the second buffer memory 21 and plays back data recorded in the second buffer memory 21. The playback unit 50 is, for example, a display device, an audio output device, or a communication device.

  The host controller 40 controls the driving of the optical disc apparatus 10 in an integrated manner. The host controller 40 includes a CPU, a ROM, and a RAM (not shown). When the host controller 40 reads data, it makes a data read request (first request) to the drive controller 30. In response to a first request issued from the host controller 40 to the drive controller 30, predetermined data recorded in the first buffer memory 20 is transferred (recorded) to the second buffer memory 21.

  The drive controller 30 controls the motor driver 12 and the optical pickup unit 13 to read data recorded on the optical disc M and write data to the optical disc M. The drive controller 30 includes a CPU, ROM, RAM, timer, interrupt controller, and I / OIF (not shown).

  FIG. 2 is a sequence diagram for explaining an output control process executed by the drive controller 30. FIG. 2 shows respective timings of the first request made from the host controller 40 to the drive controller 30 and the second request made from the drive controller 30 to the optical pickup unit 13.

The drive controller 30 functionally implements the output control means 31, the ratio calculation means 32, and the rotation control means 33 shown in FIG. 1 by executing a program recorded in the ROM.
As shown in FIG. 2, the output control unit 31 outputs a second request for causing the optical pickup unit 13 to read data recorded on the optical disc M. In the data reading performed by the second request, the data read by the optical pickup unit 13 is recorded in the first buffer memory 20 in a predetermined block unit. The block unit recorded in the first buffer memory 20 has a constant data capacity regardless of the content of the first request from the host controller 40.

  When a first request is made from the host controller 40, the drive controller 30 (output control means 31) causes the corresponding data recorded in the first buffer memory 20 to be output to the second buffer memory 21. Here, the amount of data requested by the first request is smaller than the total amount of data recorded in the first buffer memory 20, and the data requested by the first request is recorded in the first buffer memory 20. Then, only relevant data is read out. That is, during the period of reading the data recorded in the first buffer memory 20, as shown in FIG. 2, an idle time Twait (standby time) in which the drive controller 30 does not make a second request to the optical pickup unit 13 occurs. Yes. Of course, if the data requested by the first request does not exist in the first buffer memory 20, the drive controller 30 causes the optical pickup unit 13 to record the requested data in the first buffer memory 20. Since the second request is made, the idle time Twait is shortened.

  The ratio calculating means 32 calculates the ratio Rate of the idle time Twait that does not output the second request in the predetermined calculation time Tall. Here, the time Tall is a constant determined in advance by the drive controller 30.

FIG. 3 is a diagram showing the frequency with which the drive controller 30 generates the second request when playing a DVD. FIG. 3 is a graph showing the frequency of occurrence of the second request when the rotation speed is 1.6 times. The vertical axis represents the frequency of generating the second request, and the horizontal axis represents the DVD reference address. The address set on the horizontal axis is selected at random. FIG. 3 shows the data transfer rate bps at each address in addition to the frequency of the second request. As shown in FIG. 3, the drive controller 30 issues the second request at a rate of 40% to 60%.
Here, when the rotation speed of the spindle motor 11 is decreased, the data capacity recorded in the first buffer memory 20 per time is decreased.
However, as shown in FIG. 3, since the frequency of the second request has a surplus power of 40% to 60%, there is no problem in the operation of the optical disc apparatus 10 even if the rotation speed of the spindle motor 11 is decreased. Recognize.

The rotation control unit 33 causes the motor driver 12 to reduce the rotation speed of the spindle motor 11 when the calculated rate Rate is equal to or greater than the threshold value. As the rotation speed of the spindle motor 11 decreases, the power consumption of the optical disc apparatus 10 is reduced.
FIG. 4 is a diagram showing a conversion table referred to by the rotation control means 33. In FIG. 4, “1.6 times speed”, “1.8 times speed”, and “2.0 times speed” are set as the rotation speed. As the rotation speed changes from “2.0 times speed” to “1.6 times speed”, the data capacity per time recorded in the first buffer memory 20 also decreases. In this embodiment, the minimum value of the rotation speed set by the rotation control means 33 is “1.6 times speed” and the maximum value is “2.0 times speed”, but the present invention is not limited to this. Theoretically, the minimum value rotation speed can be lowered to “1.0 times speed”. It is also possible to increase the maximum value to “2.2 times speed”.

(2) Motor Rotation Speed Control Method Control of the rotation speed of the spindle motor 11 executed by the optical disc apparatus 10 will be described. FIG. 5 is a flowchart for explaining the rotation control executed by the drive controller 30.

  In step S1, the drive controller 30 (ratio calculation means 32) performs a ratio calculation process. By this ratio calculation process, the ratio of the wait time Twait to the calculation time Tall is calculated.

FIG. 6 is a flowchart illustrating the process executed in step S1 of FIG.
In step S11, the drive controller 30 starts counting the period during which the second request is made (that is, the idle time Twait).

  If the second request is not generated (step S12: NO), the drive controller 30 repeats the loop and continues counting the idle time Twait started in step S11.

  When the second request is generated (step S12: YES), in step S13, the drive controller 30 records the count value Count (i). Here, (i) is an identifier for identifying each count value Count. In the first embodiment, since the idle time Twait is calculated by the sum of a plurality of counts (i) included in the calculation time Tall, each count value Count (i) is identified by i. In step S <b> 14, the drive controller 30 stands by until the time required to record data in the first buffer memory 20 (data recording time).

In step S15, if the time Time from the start of counting (step S11) to the present time has not reached the predetermined time Tall, the drive controller 30 proceeds to step S16.
In step S16, the drive controller 30 changes the identifier i by adding 1 to the identifier i.

  And the drive controller 30 repeats the process of step S11-S14.

When the time Time from the start of counting (step S11) to the current time reaches a predetermined time Tall (step S15: YES), the drive controller 30 proceeds to step S17.
In step S17, the drive controller 30 calculates the idle time Twait based on the following formula (1).
Idle time Twait = ΣCount (i) (1)
Here, ΣCount (i) indicates the total sum of the count values Count (i) for each identifier i recorded in step S13.

In step S18, the drive controller 30 calculates the rate Rate based on the following equation (2) from the idle time Twait calculated in step S17.
Rate Rate = Twait / Tall (2)
As described above, the time Tall is a constant determined in advance by the drive controller 30.

  Returning to FIG. 5, in step S2, the drive controller 30 (rotation control means 33) performs a rotation control process. In this rotation control process, the rotation speed of the spindle motor 11 is set based on the rate Rate calculated in step S1.

FIG. 7 is a flowchart for explaining the rotation control process executed in step S2.
In step S21, the drive controller 30 acquires the rate Rate.

  If the rate Rate is less than the threshold value T1 (step S22: NO), in step S24, the drive controller 30 refers to the double speed table and sets the rotational speed RPM to RPM0. Here, the rotational speed RPM is a parameter for the motor driver 12 to set the rotational speed of the spindle motor 11. RPM0 is the default rotation speed of the spindle motor 11. For example, RPM0 is the rotation speed of the spindle motor 11 corresponding to the data transfer amount (bps) of the optical disc M of “2.0 times speed”.

  For example, when random access occurs to the optical disc M, the second request frequently occurs. That is, new data is read without using all the data recorded in the first buffer memory 20. For example, by calculating the threshold value T1 based on the rate Rate when random access occurs, if random access occurs, the rotation speed of the spindle motor 11 is maintained at the default, and the reproduction performance of the optical disc apparatus 10 is reduced I won't let you.

If the rate Rate is greater than the threshold value T1 (step S22: YES), the drive controller 30 proceeds to step S23.
In step S23, if the rate Rate is less than the threshold value T2 (step S23: NO), the drive controller 30 proceeds to step S26.
In step S26, the drive controller 30 sets the rotation speed RPM to RPM1. Here, RPM1 is a rotational speed that is one step lower than the default rotational speed of the spindle motor 11. For example, “1.8 times speed”.

In step S23, if the rate Rate is larger than the threshold value T2 (step S23: YES), the drive controller 30 proceeds to step S25.
In step S25, the drive controller 30 sets the rotation speed RPM to RPM2. Here, RPM2 is the lowest rotation speed that the spindle motor 11 can set. For example, RPM0 is the rotation speed of the spindle motor 11 corresponding to the data transfer amount (bps) of the optical disc M of “1.6 times speed”.

  In step S <b> 27, the drive controller 30 transmits the set rotation speed RPM to the motor driver 12. When the motor driver 12 receives the rotation speed RPM, the motor driver 12 changes the rotation speed of the spindle motor 11 based on the rotation speed RPM.

  Returning to FIG. 5, in step S3, the drive controller 30 returns to step S1 and repeats the process unless the condition (end condition) for ending the process is satisfied (step S3: NO). Here, the termination condition is, for example, when the main power supply of the optical disc apparatus 10 is turned off.

  As described above, in the first embodiment, the data in the buffer memory is used to adjust the rotation speed of the spindle motor 11 in accordance with the ratio of the wait time Twait when the output control means 31 does not make the second request. The rotational speed of the motor can be adjusted without monitoring the capacity.

Moreover, the ratio calculation means 32 can implement | achieve acquisition of idle time Twait by a simpler method by counting the period when the 2nd request | requirement has not generate | occur | produced.
And since the rotation control means 33 reduces the rotational speed of the motor stepwise in accordance with the ratio Rate, it is possible to achieve a reduction in power consumption and the reproduction performance of the apparatus in a balanced manner.
Further, when the ratio Rate is low, the rotation control unit 33 causes the motor driver 12 to return the rotation speed of the motor to the initial value, so that reduction in power consumption and reproduction performance of the apparatus can be realized in a balanced manner.

2. Second embodiment:
In the second embodiment, when the output control means 31 performs CLV rotation control according to the reproduction position of the optical disc M, the calculation time (when calculating the rate Rate according to the address of the optical disc M from which data is read) The configuration in which (Tall) changes is different from that of the first embodiment.

  FIG. 8 is a diagram illustrating CLV rotation control. The circumference of the optical disc M decreases as it goes to the inner peripheral side In, and conversely increases as it goes to the outer peripheral side Out. Further, since the intervals of data (pits) recorded on the optical disc M are uniform, the amount of information read per rotation when the reference address is the inner circumference side In is 1 when the reference address is the outer circumference side Out. Compared to the amount of information read per rotation. Therefore, in the CLV rotation control performed by the output control means 31, when the data reference address is on the inner circumference side In of the optical disc, the rotation speed of the optical disc M is increased, while the data reference address is on the outer circumference side of the optical disc M. In the case of Out, the rotation speed of the optical disk is slowed down. Therefore, the data transfer rate bps read by the optical pickup unit 13 is kept constant.

FIG. 9 is a flowchart illustrating a ratio calculation process executed by the ratio calculation unit 32 in the second embodiment. As described above, in the CLV rotation control, when the reference address is the inner peripheral side In, the rotation speed of the spindle motor 11 is increased. As a result, power consumption increases. Therefore, in the flowchart shown in FIG. 9, when the data reference address is the inner circumference side In of the optical disc M, the ratio calculation means 32 calculates the calculation time (Tall) for calculating the ratio Rate compared to the case of the outer circumference side Out. It is long. As a result, on the inner peripheral side, the rapid change in the rotation speed of the spindle motor 11 is suppressed, and an increase in power consumption is reduced.
In the second embodiment, the address of the optical disc M is divided into two by the inner circumference In and the outer circumference Out, and calculation times (Tall1, Tall2) when the reference address corresponds to each area are set. . Of course, the present invention is not limited to this, and the number of divisions of the optical disk M may be increased to two or more, and the respective calculation times may be set.

In step S111, the drive controller 30 starts counting.
If the second request has not been generated (step S112: NO), the drive controller 30 repeats the loop.

  When the second request is generated (step S112: YES), in step S113, the drive controller 30 records the count value Count (i). Here, (i) is an identifier for identifying each count value Count. In step S114, the drive controller 30 stands by until the data recording time.

If the address of the reference destination of the optical disc M is the inner circumference side (step S115: YES), the drive controller 30 proceeds to step S116. The address acquisition method is determined based on, for example, an instruction output from the host controller 40.
In step S116, the drive controller 30 proceeds to step S118 if the time Time from the start of counting to the present time has not reached the predetermined time Tall1 (NO in step S116). Here, the time Tall1 is longer than the time Tall2 described later.

In step S118, the drive controller 30 changes the identifier i by adding 1 to the identifier i.
Then, the drive controller 30 returns to step S111 and repeats the process.

On the other hand, if the reference destination address of the optical disc M is not on the inner circumference side (step S115: NO), the drive controller 30 proceeds to step S117.
In step S117, if the time Time from the start of counting to the present time has not reached the predetermined time Tall2 (step S117: NO), the drive controller 30 proceeds to step S118.

When the reference destination address is on the inner circumference side (step S115: YES) and the time Time from the start of counting until the present time reaches a predetermined time Tall1 (step S116: YES), the drive controller 30 performs step The process proceeds to S119.
In step S119, the drive controller 30 calculates the idle time Twait based on the above (1).

In step S120, the drive controller 30 calculates the rate Rate from the idle time Twait calculated in step S119 based on the following equation (3).
Rate Rate = Twait / Tall1 (3)
As described above, the time Tall1 is a time (constant) predetermined by the drive controller 30 when the reference address of the optical disc M belongs to the inner circumference side.

When the reference destination address is not on the inner circumference side (step S115: NO) and the time Time from the start of counting until the present time reaches a predetermined time Tall2 (step S117: YES), the drive controller 30 performs step The process proceeds to S121.
In step S121, the drive controller 30 calculates the idle time Twait based on the above (1).

In step S122, the drive controller 30 calculates the rate Rate based on the following equation (4) from the idle time Twait calculated in step S121.
Rate Rate = Twait / Tall2 (4)
As described above, the time Tall2 is a time (constant) predetermined by the drive controller 30 when the reference address of the optical disc M belongs to the outer peripheral side.

  Then, the process proceeds to step S2 in FIG. 5, and the rotation speed of the spindle motor 11 is set based on the calculated rate Rate.

  As described above, in the second embodiment, when the CLV rotation control is performed, the ratio calculation is performed when the reference address of the data is the inner peripheral side In of the optical disc M compared to the outer peripheral side Out. The means 32 increases the calculation time (Tall) for calculating the rate Rate. As a result, on the inner peripheral side In, it is possible to suppress a rapid change in the rotation speed of the spindle motor 11 and to reduce an increase in power consumption.

3. Third embodiment:
When the spindle motor 11 is configured to reduce the rotational speed by applying a brake voltage to the speed reducer, the rotational speed may be decreased by inertia instead of decreasing the rotational speed by applying the brake voltage. For example, when the rotation of the spindle motor 11 is reduced in step S27 of FIG. 5, the drive controller 30 outputs a command to the motor driver 12 so as not to generate a brake voltage. When receiving a command from the drive controller 30, the motor driver 12 does not generate a brake voltage and decreases the rotation speed of the spindle motor 11.

  As described above, in the third embodiment, since no brake voltage is generated when the spindle motor is decelerated, the power consumption can be further reduced.

4). Fourth embodiment:
Two or more calculation times Tall that are times for measuring the idle period may be prepared, and the rotation speed of the spindle motor 11 may be controlled according to each calculation time Tall.

  FIG. 10 is a diagram illustrating a ratio of the wait time Twait to each calculation time Tall in the fourth embodiment. In FIG. 4, the vertical axis is the rate, and the horizontal axis is a diagram showing the change of the rate when the time is changed. FIG. 10 shows the change in the rate Rate corresponding to Tall1 and Tall2, which is longer than Tall1, as the calculation time Tall.

Tall1 is used to calculate the change (rate Rate) of the transfer rate in a short time. As shown in FIG. 10, when the transfer rate increases in a short time, the rotation control means 33 increases the rotation speed of the spindle motor 11. Tall1 can be set to 5 seconds, for example.
Tall2 is used to calculate the change (rate Rate) of the transfer rate over a long time. When the rate Rate at Tall 2 is less than or equal to the threshold value, the rotation control means 33 decreases the rotation speed of the spindle motor 11. Tall can be set to, for example, 50 seconds.

  FIG. 11 is a flowchart for explaining processing executed by the drive controller 30.

  In step S31, if the end condition is not satisfied (step S31: NO), the drive controller 30 proceeds to step S32.

  In step S32, the drive controller 30 (ratio calculation means 32) performs a ratio calculation process. In the ratio calculation process of step S32, the drive controller 30 calculates the ratio Rate of the wait time Twait occupying the calculation time Tall1 in the process shown in FIG.

  In step S33, the drive controller 30 adds the calculation time Tall1 to the integration time CountSum and updates the integration time CountSum. The accumulated time CountSum is a value for calculating the calculation time Tall2, and indicates the current cumulative time.

  In step S34, if the rate Rate acquired in step S32 is greater than or equal to the threshold T3 (step S34: YES), the drive controller 30 proceeds to step S35. The threshold value T3 is a value indicating a change in transfer rate during the calculation time Tall1. In step S35, the drive controller 30 sets the rotation speed of the stepping motor 11 to the default (RPM1) rotation speed. In the fourth embodiment, the rotation speed of the stepping motor 11 is decreased in the order of the rotation speeds RPM0, RPM1, and RPM2, and the rotation speed for setting the rotation speed of the stepping motor 11 in the normal time (default) is set to RPM1. And In step S36, the drive controller 30 updates RatePre based on RatePre indicating the ratio in the accumulated time CountSum and the ratio Rate calculated in step S32.

  On the other hand, if the rate Rate acquired in step S32 is less than the threshold T3 (step S34: NO), the drive controller 30 proceeds to step S37. In step S37, the drive controller 30 sets the rotational speed RPM for setting the rotational speed of the stepping motor 11 to a value (RPM0) that is slower than normal.

  In step S38, the drive controller 30 clears the accumulated time CountSum and the current rate RatePre. Then, the drive controller 30 returns to step S31. That is, in the fourth embodiment, when the rate Rate is low at the calculation time Tall1, the count of the calculation time Tall2 is initialized.

In step S39, the drive controller 30 compares the integration time CountSum with Tall2. Here, since the current time CountSum is smaller than the calculation time Tall2 (step S38: NO), the process returns to step S31.
Hereinafter, the drive controller 30 repeats the processes of steps S31 to S38.

In step S39, when the accumulated time CountSum is the calculation time Tall2 (step S39: YES), the drive controller 30 proceeds to step S40. If the rate RatePre in the accumulated time CountSum acquired in step S36 is greater than or equal to the threshold T4 (step S40; YES), the drive controller 30 proceeds to step S41. In step S41, the drive controller 30 sets the rotation speed RPM of the stepping motor 11 to a lower value (RPM2) than normal.
In step S42, the drive controller 30 clears the accumulated time CountSum and the current rate RatePre.

In step S40, if the rate RatePre acquired in step S36 is less than the threshold T4 (step S40; NO), the drive controller 30 proceeds to step S43. In step S43, the drive controller 30 sets the rotation speed RPM of the stepping motor 11 to a normal value (default) (RPM1).

  Returning to step S31, if the end condition is satisfied (step S31: YES), the drive controller 30 ends the process.

  As described above, in the fourth embodiment, the drive controller 30 changes the rotation speed of the motor according to the change in the transfer speed in the short time (Tall 1) and the long time (Tall 2) as the calculation time. Therefore, power consumption can be controlled more flexibly.

5. Other Embodiments Changing the rotation speed of the spindle motor 11 to “1.6 times speed”, “1.8 times speed”, and “2.0 times speed” is merely an example. For example, the maximum speed may be “1.6 times speed” and the minimum speed may be 1.0 times speed. In this case, when the rate Rate is less than the threshold value T1 in step S22 of FIG. 5, the reproduction performance of the optical disc apparatus 10 can be prevented from being lowered by returning to “1.6 × speed”.

  The use of separate memories of the first buffer memory 20 and the second buffer memory 21 as the buffer memory is merely an example. For example, the function of the first buffer memory 20 and the second buffer memory 21 may be realized by dividing one buffer memory area into two.

Needless to say, the present invention is not limited to the above embodiments. It goes without saying for those skilled in the art,
・ Applying mutually interchangeable members and configurations disclosed in the above embodiments by appropriately changing the combination thereof.− Although not disclosed in the above embodiments, it is a publicly known technique and the above embodiments. The members and configurations that can be mutually replaced with the members and configurations disclosed in the above are appropriately replaced, and the combination is changed and applied. It is an embodiment of the present invention that a person skilled in the art can appropriately replace the members and configurations that can be assumed as substitutes for the members and configurations disclosed in the above-described embodiments, and change the combinations and apply them. It is disclosed as.

  DESCRIPTION OF SYMBOLS 10 ... Optical disk apparatus, 11 ... Spindle motor, 12 ... Motor driver, 13 ... Optical pick-up unit, 14 ... RF circuit, 15 ... Address decoding circuit, 16 ... Encoding / decoding circuit, 20 ... 1st buffer memory, 21 ... 2nd Buffer memory 30 ... Drive controller 31 ... Output control means 32 ... Ratio calculation means 33 ... Rotation control means 40 ... Host controller 50 ... Reproducing unit

Claims (7)

A motor driver that drives a motor that rotates the optical disc;
An optical pickup for reading data recorded on the optical disc;
A buffer memory for recording data read by the optical pickup;
A host controller that outputs a first request for the data;
An output control means for outputting a second request for causing the optical pickup to read data recorded on the optical disc, and outputting the data recorded in the buffer memory in response to the first request;
A ratio calculating means for calculating a ratio of a waiting time during which the second request is not output in a predetermined time;
An optical disc apparatus comprising: a rotation control unit that causes the motor driver to reduce the rotation speed of the motor when the calculated ratio is equal to or greater than a threshold value.   2. The optical disc apparatus according to claim 1, wherein the ratio calculating unit acquires the waiting time by counting a period in which the second request is not generated.   The optical disk apparatus according to claim 1, wherein the rotation control unit decreases the rotation speed of the motor in a stepwise manner in accordance with the ratio. The rotation control means performs CLV rotation control,
When the optical pickup refers to the address on the inner peripheral side of the optical disc, the predetermined time is lengthened compared to the case of referring to the address on the outer peripheral side of the optical disc. The optical disc device according to any one of claims 1 to 3.   5. The optical disc apparatus according to claim 1, wherein the rotation control unit does not apply a brake voltage when the rotational speed of the motor is decreased. 6.   The said rotation control means makes the said motor driver return the rotational speed of the said motor to the initial value, when the calculated said ratio is low, The any one of Claims 1-5 characterized by the above-mentioned. The optical disk device described. The ratio calculating means calculates the ratio at a first time that is the predetermined time and a second time that is longer than the first time,
The rotation control means increases the rotation speed of the motor when the ratio at the first time is low, and decreases the rotation speed of the motor when the ratio at the second time is high. The optical disc apparatus according to any one of claims 1 to 5, wherein

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