JP3538131B2 - Disc reproducing apparatus and method of shielding objective lens - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk reproducing apparatus and an objective lens shielding method capable of properly dust-proofing an objective lens even during a reproducing operation.

[0002]

2. Description of the Related Art Music CDs (compact discs) and M
With the spread of D (mini-disc), CD players and M
A disk player represented by a D player has been widely used as one of the most popular music players. These disc reproducing devices use an optical pickup to irradiate a laser beam onto a recording surface of a disc via an objective lens, and to condense reflected light from the disc onto a photodetector or the like via the same objective lens. Reading data recorded on the disc.

[0003] In some of such disc reproducing apparatuses, a shutter for covering the upper part of the objective lens is provided in order to prevent dust or dust from adhering to the objective lens of the optical pickup. Hereinafter, a conventional disk reproducing apparatus having a dustproof shutter will be described with reference to FIG. FIG. 6 shows a conventional disk reproducing apparatus (main part).
It is a top view which shows the structure of.

[0006] The disc reproducing apparatus shown in FIG. 6 includes an optical pickup 101 in which an objective lens 102 is embedded, a shutter 103 for shielding the objective lens 102, and an optical pickup 101 in a radial direction of the disc (outer side in FIG. Or the inner peripheral side) and a sled motor 105 for driving the lead screw 104 to rotate.
And a boss 106 erected at a predetermined position in the chassis. The shutter 103 has a shaft 103
a and rotatably supported by a spring member 103b.
Accordingly, the objective lens 102 is urged in the opening direction (the L direction in the drawing).

[0005] In such a disk reproducing apparatus, for example, when the user gives an instruction to turn off the power, the drive of the thread motor 105 is controlled by a predetermined control unit, and the optical pickup 101 is moved out of the disk information area (the information of the disk is read). (A position that cannot be read). The shutter 103 comes into contact with the boss 106 immediately before the optical pickup 101 reaches the outer peripheral end. When the optical pickup 101 reaches the outer peripheral end, the shutter 103 is pressed by the boss 106 and rotates to shield the objective lens 102. Specifically, when the optical pickup 101 moves to the outer peripheral side in the drawing as the lead screw 104 rotates, the shutter 103 comes into contact with the boss 106. As the optical pickup 101 further moves to the outer peripheral side, the shutter 103 pressed by the boss 106 rotates around the shaft 103a in the R direction in the figure to shield the objective lens 102. In this state, the optical pickup 101 comes into contact with a predetermined stopper and stops.

As described above, the disk reproducing apparatus as shown in FIG.
Is shielded by the shutter 103, so that dust and dirt can be prevented from adhering to the objective lens 102.

[0007]

However, such a conventional disk reproducing apparatus may not be able to provide sufficient dust protection. This is because the shutter 103 blocks the objective lens 102 only when the power is off.

For example, it is expected that a disk reproducing apparatus used for a vehicle is used in an environment where a lot of dust or dust flies during traveling or the like. In such an environment, a large amount of dust or dirt adheres to the objective lens 102 in the disc reproducing apparatus even during the reproducing operation. If dust or dust exceeding the limit amount adheres to the objective lens 102, there is a problem that data reading errors and the like frequently occur, which hinder reproduction of music and the like.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a disk reproducing apparatus and an objective lens shielding method capable of appropriately dust-proofing an objective lens even during a reproducing operation.

[0010]

In order to achieve the above object, a disk reproducing apparatus according to a first aspect of the present invention comprises: an optical reading means having an objective lens for reading compressed data recorded on a disk; Shielding means for movably holding a shielding member disposed near the objective lens of the optical reading means between a position covering the objective lens and a position for opening the objective lens; Storage means for sequentially storing the compressed data, decoding means for sequentially decoding the compressed data stored in the storage means,
Output means for outputting the data decoded by the decoding means as audio, and compressed data read by the optical reading means for a predetermined time and stored in the storage means,
Control means for controlling the shielding means during the decoding by the decoding means to shield the objective lens of the optical reading means.

According to the present invention, the optical reading means comprises an optical pickup or the like, has an objective lens, and reads out, for example, 5-fold compressed data recorded on a disk. The shielding means movably holds the shielding member disposed near the objective lens of the optical reading means between a position for covering the objective lens and a position for opening the objective lens. The storage means is, for example, a DRAM or the like, and sequentially stores the compressed data read by the optical reading means. The decoding means decodes the compressed data stored in the storage means. The output unit includes, for example, a speaker or the like, and outputs data decoded by the decoding unit as audio. The control means controls the shielding means and shields the objective lens of the optical reading means while the decoding means decodes the compressed data read by the optical reading means for a predetermined time and stored in the storage means. As a result, even during the reproducing operation, the objective lens can be properly dust-proofed.

In order to achieve the above object, a disc reproducing apparatus according to a second aspect of the present invention comprises an optical pickup having an objective lens embedded therein and supported movably in a radial direction of the disc by a predetermined guide shaft; A shutter rotatably supported by a rotating shaft erected in contact with the optical pickup, a motor for moving the optical pickup in a radial direction of the disk, and a standby position which is an end of the movement of the optical pickup. A protruding member that is erected, contacts the shutter that has moved with the optical pickup, and rotates the shutter; storage means for demodulating and sequentially storing compressed data read from the disk by the optical pickup;
Output means for outputting digital data as audio; andcompressed data read out by the optical pickup for a predetermined time and stored in the storage means, while the decoding means decodes the data, thereby controlling the motor to operate the optical pickup. And a control means for moving the shutter to the standby position and bringing the shutter into contact with the protruding member so as to shield the objective lens of the optical pickup by the rotated shutter.

According to the present invention, the optical pickup has the objective lens embedded therein and is supported by the guide shaft so as to be movable in the radial direction of the disk. The shutter is rotatably supported by a rotating shaft erected in contact with the optical pickup. The motor includes, for example, a spindle motor, and moves the optical pickup in the radial direction of the disk via a lead screw. The protruding member is erected at a standby position at the end of the movement of the optical pickup, contacts the shutter that has moved together with the optical pickup, and rotates the shutter.
The storage means includes a DRAM or the like, and sequentially stores, for example, five-fold compressed data read from the disk by the optical pickup. The output means includes, for example, a speaker or the like, and outputs digital data as voice. The control means controls the motor to move the optical pickup to the standby position while the decoding means decodes the compressed data read by the optical pickup for a predetermined time and stored in the storage means, and moves the shutter to the projection member. The contact allows the objective lens of the optical pickup to be shielded by the rotated shutter. As a result, even during the reproducing operation, the objective lens can be properly dust-proofed.

In order to achieve the above object, a disk reproducing apparatus according to a third aspect of the present invention comprises: a reading means for intermittently reading compressed data recorded on a disk via an optical pickup having an objective lens; A moving means for moving the pickup in the radial direction of the disc; and a moving member arranged in the vicinity of the objective lens of the optical pickup. A shielding member that is pressed to shield the objective lens, a storage unit that sequentially stores the compressed data read by the reading unit, an output unit that demodulates the compressed data stored in the storage unit, and outputs the data as audio, While the reading means stops reading, the controlling means controls the moving means to move the optical pickup to a standby position, and And control means for shielding the objective lens of the optical pickup Ri, characterized in that it comprises a.

According to the present invention, the reading means intermittently reads, for example, 5-fold compressed data recorded on the disk via the optical pickup having the objective lens. The moving means moves the optical pickup in the radial direction of the disk. The shielding member is arranged near the objective lens included in the optical pickup, and is pressed by a predetermined member to shield the objective lens when the optical pickup is transported to the standby position where the movement ends by the moving means. The storage means is
The compressed data read by the reading means is sequentially stored. The output unit demodulates the compressed data stored in the storage unit and outputs the demodulated data as audio. The control unit controls the moving unit to move the optical pickup to the standby position while the reading unit stops reading, and shields the objective lens of the optical pickup with the shielding member. As a result, even during the reproducing operation, the objective lens can be properly dust-proofed.

To achieve the above object, a method for shielding an objective lens according to a fourth aspect of the present invention includes an optical pickup having an objective lens embedded therein and supported by a guide shaft so as to be movable in a radial direction of a disk, and an optical pickup. A shutter rotatably supported by a rotating shaft erected in contact with the pickup;
It is erected at a standby position at the end of the movement of the optical pickup, contacts the shutter that has moved with the optical pickup,
A method of shielding an objective lens of a disk reproducing apparatus having a projection member for rotating a shutter, the method comprising: reading compressed data recorded on a disk via an optical pickup; and storing the compressed data in a predetermined storage unit. A decoding step of sequentially decoding the compressed data read from the disk and stored in the storage unit in the compressed data reading step; and moving the optical pickup to a standby position while the compressed data is decoded in the decoding step. And controlling the shutter to abut the projecting member so that the objective lens of the optical pickup is shielded by the rotated shutter.

According to the present invention, in the compressed data reading step, the compressed data, for example, compressed five times, which is recorded on the disk via the optical pickup, is read and stored in a predetermined storage unit. The decoding step sequentially decodes the compressed data read from the disk in the compressed data reading step and stored in the storage unit. The control steps are
While the compressed data is decoded in the decoding step, the optical pickup is moved to the standby position, and the shutter is brought into contact with the projection member, so that the objective lens of the optical pickup is shielded by the rotated shutter. As a result, even during the reproducing operation, the objective lens can be properly dust-proofed.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A disk reproducing apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing an example of a disk reproducing apparatus applied to the embodiment of the present invention. As shown in FIG. 1, the disc reproducing apparatus includes an optical pickup 1
, Objective lens 2, shutter 3, boss 4, thread motor 5, lead screw 6, spindle motor 7, turntable 8, RF amplifier 9, DSP 1
0, a driver 11, a DRAM 12, and a decoder 13
, A DAC 14 and a speaker 15,
The disc 20 placed on the turntable 8 is reproduced. The disk 20 is, for example, an MD (mini-disc), and has a TRACK (Adaptive TRansform Acoust).
ic Codindg), audio data that has been compressed five times is recorded.

The optical pickup 1 is driven by a predetermined guide shaft or the like so that data can be appropriately read from the disk 20 mounted on the turntable 8.
It is supported movably in the radial direction of 0. Objective lens 2
Is buried in the surface of the optical pickup 1, irradiates a predetermined laser beam, and receives reflected light.

That is, the optical pickup 1 irradiates a predetermined laser beam to the recording surface of the disk 20 via the embedded objective lens 2 and condenses the reflected light on the photodiode via the objective lens 2. Thus, reading of audio data and the like are performed. The optical pickup 1 controls the FC (focus control) and the TC (tracking control) by the driver 1 according to the focus error signal and the tracking error signal.
1 to control focus servo and tracking servo.

The shutter 3 is made of a thin plate or the like having a predetermined shape, and shields and opens the objective lens 2 with rotation about a rotation axis. Specifically, the shutter 3
Is supported by a shaft 3a and rotates about the shaft 3a, as shown in FIGS. And shutter 3
, A spring member 3b is attached, and is urged in the L direction shown in FIG. 2A by the spring member 3b. Therefore, in the reading state (at the time of reading data from the disk 20), the shutter 3 is opened without covering the objective lens 2.

In a standby state (during standby for reading), when the optical pickup 1 moves to the outer peripheral side and reaches just before the outer peripheral end, the shutter 3 comes into contact with the boss 4. And
As shown in FIG. 2B, as the optical pickup 1 further moves to the standby position, which is the outer peripheral end, the shutter 3 pressed by the boss 4 rotates around the shaft 3a in the R direction in the figure. Then, the objective lens 2 is shielded. The boss 4 is erected near the outer peripheral portion of the disk 20 in the chassis, and comes into contact with the shutter 3 when the optical pickup 1 moves near the outer peripheral end.

Returning to FIG. 1, the sled motor 5 is driven to rotate in accordance with the SL signal supplied from the driver 11. The thread motor 5 rotates the lead screw 6 with its own rotation, and moves the optical pickup 1 in the radial direction of the disk 20. The lead screw 6 is shown in FIG.
As shown in (a) and (b), the optical pickup 1 is moved to the outer peripheral side or the inner peripheral side of the disk 20 with its own rotation. That is, the lead screw 6 is movably supported by a guide shaft (not shown) or the like.
Is appropriately moved in the radial direction of the disk 20 as the thread motor 5 rotates.

Returning to FIG. 1, the spindle motor 7 is driven to rotate in accordance with the SP signal supplied from the driver 11 together with the turntable 8 fitted on the rotating shaft. Specifically, the spindle motor 7 drives the disk 20 placed on the turntable 8 at a constant linear velocity, for example, in accordance with the SP signal. The turntable 8 is fitted on the rotation axis of the spindle motor 7 and rotates with the rotation of the spindle motor 7. On the turntable 8, a disk 20 to be reproduced is placed.

The RF amplifier 9 receives audio data (for example, 5
Is supplied to the DSP 10. Further, the RF amplifier 9 generates a focus error signal and a tracking error signal according to the signal sent from the optical pickup 1, and converts the generated focus error signal and the like into a D signal.
Supply to SP10.

DSP (Digital Signal Processor) 10
Controls the entire disc reproducing apparatus. DSP10 is
The audio data sent from the RF amplifier 9 is transferred to the DRAM
12 sequentially. Also, the DSP 10 has a driver 1
The optical pickup 1, the sled motor 5, the spindle motor 7, and the like are driven and controlled via the control unit 1. For example, DSP
The reference numeral 10 supplies the SL signal to the thread motor 5 via the driver 11 to move the optical pickup 1 to a data reading position and a standby position as appropriate.

The driver 11 is composed of a motor driving IC or the like, and is controlled by the DSP 10 to supply predetermined control signals to the optical pickup 1, the sled motor 5, and the spindle motor 7. For example, the driver 11 generates an SP signal for rotating the disk placed on the turntable 8 at a constant linear speed, and supplies the SP signal to the spindle motor 7.

DRAM (Dynamic Random Access Memor)
y) 12 is, for example, a dual port RAM capable of performing writing and reading independently, and a DSP
The audio data supplied from 10 is sequentially stored.
A predetermined amount of audio data is stored in the DRAM 12 and sequentially read out via the decoder 13. The decoder 13 reads data from the DRAM 12 and decodes the data. That is, the decoder 13 converts the data compressed by a factor of 5 according to the ATRAC method into compressed audio data and outputs the audio data to the speaker 15 via the DAC 14.

DAC (Digital-to-Analog Converter) 1
4 converts the audio data from the decoder 13 into an analog signal (audio signal) and supplies it to the speaker 15. The speaker 15 vibrates the cone paper or the like according to the audio data supplied via the DAC 14 and outputs it as a sound (music sound).

Hereinafter, the operation of the disc reproducing apparatus according to the embodiment of the present invention will be described with reference to the drawings. First, read audio data compressed 5 times,
The relationship with the reproduction will be described with reference to FIG. FIG. 3 is a timing chart for explaining a read time (ta) for reading audio data and a standby time (ts) in which audio data need not be read.

For example, audio data is read out from the disk 20 via the optical pickup 1 for 10 seconds,
When stored in the AM 12, playback for 50 seconds is possible through the decoder 13. Here, even if a margin of 10 seconds is provided so that the sound is not cut off even if a shock such as vibration is received, it is not necessary to read audio data from the disk 20 for 40 seconds. That is, DSP10
Intermittently reads audio data at a 5 × rate (5 × compressed) from the disk 20 via the optical pickup 1 for 10 seconds (ta), stores it in the DRAM 12, and stops reading for 40 seconds (ts). Read operation.

It should be noted that, in parallel, the decoder 13
An operation is performed in which the audio data stored in M12 is decoded into audio data of a 1 × rate and output for 50 seconds. By repeatedly performing these operations, the disc 20 can be reproduced without interruption.
Then, the DSP 10 moves the optical pickup 1 to the standby position at the outer peripheral end using 40 seconds (ts) during which reading from the disk 20 is stopped. In this case, the objective lens 2 can be shielded by the shutter 3 for a predetermined time (40 seconds−moving time × 2).

Next, a specific operation of the disc reproducing apparatus will be described with reference to FIG. FIG. 4A is a flowchart for explaining the data intermittent reading process, and FIG. 4B is a flowchart for explaining the music reproduction process. Note that the data intermittent reading process and the music reproduction process are executed in parallel.

First, the data intermittent reading process shown in FIG. The data intermittent reading process starts when the reproduction of the disc 20 is instructed via a predetermined operation unit, and ends when, for example, all the audio data of the last music piece recorded on the disc 20 is read. .

First, the DSP 10 reads audio data from the disk 20 and writes it to the DRAM 12 (step S11). That is, the DSP 10 controls the optical pickup 1 via the driver 11, reads out audio data compressed five times for a predetermined time (ta), and sequentially stores the audio data in the DRAM 12.

The DSP 10 holds the read position of the audio data (step S12). That is, DSP1
0 holds the read position currently read on the disk 20.

The DSP 10 moves the optical pickup 1 to a standby position at the outer peripheral end (step S13). That is, the DSP 10 controls the thread motor 5 via the driver 11 to move the optical pickup 1 to a standby position at the outer peripheral end. At this time, as the optical pickup 1 further moves to the standby position, the shutter 3 pressed by the boss 4 rotates about the shaft 3a to shield the objective lens 2.

The DSP 10 causes the optical pickup 1 to wait at the standby position until a predetermined time (ts) has elapsed (step S14). That is, during this time, the shutter 3 keeps blocking the objective lens 2.

After the lapse of a predetermined time, the DSP 10 moves the optical pickup 1 to the reading position held in step S12 (step S15). The DSP 10 performs step S
Then, the process returns to step S11, and the processes of steps S11 to S15 are repeatedly executed. That is, the DSP 10 repeats intermittent reading.

Next, the music reproduction processing shown in FIG. 4B will be described. The music reproduction processing is started when a predetermined amount of audio data is stored in the DRAM 12 by the intermittent data reading processing.

First, the decoder 13 reads audio data from the DRAM 12 under the control of the DSP 10 (step S21). That is, the decoder 13 reads the audio data compressed five times.

The decoder 13 decodes the compressed audio data (Step S22). That is, the decoder 13 generates compressed audio data.

The decoder 13 outputs the decoded audio data from the speaker 15 via the DAC 14 (step S23). That is, the music read from the disk 20 is output from the speaker 15. The decoder 13 repeatedly executes the processing of steps S21 to S23 described above. That is, the decoder 13 is connected to the DRAM 12
Is repeated until all the audio data stored in is read out and decoded.

As described above, in the intermittent audio data reading operation performed via the optical pickup 1, at the timing when reading is stopped, the optical pickup 1 is moved to the standby position at the outer peripheral end, and the objective lens 2 is shuttered. 3 for shielding. As a result, even during the reproducing operation, the objective lens 2 can be properly dust-proofed.

In the above embodiment, the optical pickup 1
Is moved to the outer peripheral side, and the shutter 3 is brought into contact with the boss 4 to shield the objective lens 2. However, the position at which the shutter 3 is shielded is arbitrary. For example, the boss 4 is erected at a standby position which is the inner peripheral end of the disk 20, the optical pickup 1 is moved to the inner peripheral side at the timing when reading is stopped, the shutter 3 is brought into contact with the boss 4, and the objective lens is moved. 2 may be shielded.

In the above embodiment, the optical pickup 1
Is moved to the standby position where the boss 4 is erected, so that the objective lens 2 is shielded by the shutter 3. However, the objective lens 2 can be shielded by the shutter 3 without moving the optical pickup 1 to the standby position. May be. For example, by arranging a shutter rotating mechanism as shown in FIG. 5 near the objective lens 2, the objective lens 2 can be shielded by the shutter 3 without moving the optical pickup 1 to the standby position.

The shutter rotating mechanism shown in FIG. 5 includes a magnet 31, a yoke 32, and a coil 33. The shutter 3 is rotated by a magnetic field generated in the coil 33, with the rotating shaft being penetrated into the coil 33. In addition,
The DSP 10 can supply a current in the first direction and a current in the second direction to the electric wire of the coil 33 via a predetermined drive circuit. When reading audio data, the DSP 10 supplies a current in the first direction to the electric wire of the coil 33 and opens the shutter 3. When stopping reading, the DSP 10 supplies a current in the second direction to the electric wire of the coil 33, and the shutter 3 shields the objective lens. In this case as well, even during the reproducing operation, the objective lens 2
Can be properly dust-proofed.

Further, in the above-described embodiment, the disc reproducing apparatus for reproducing the MD has been described. However, the medium to be reproduced is not limited to the MD, but may be a disc for reproducing a CD, a DVD (digital video disc) or the like. It is applicable to a playback device.

[0050]

As described above, according to the present invention,
Even during the reproducing operation, the objective lens can be properly protected from dust.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of a configuration of a disc reproducing apparatus according to an embodiment of the present invention.

FIGS. 2A and 2B are plan views for explaining an operation of a shutter for shielding an objective lens, where FIG. 2A is a diagram illustrating a state where a shutter is opened, and FIG. 2B is a diagram illustrating a state where a shutter is closed. is there.

FIG. 3 is a timing chart for explaining operation timings of a thread motor, a DRAM, a spindle motor, and the like.

FIG. 4A is a flowchart for explaining an intermittent data read process according to the embodiment of the present invention;
(B) is a flowchart for explaining the music reproduction processing according to the embodiment of the present invention.

FIG. 5 is a perspective view showing an example of a shutter rotation mechanism according to another embodiment of the present invention.

FIG. 6 is a plan view showing an example of the configuration of a conventional disk reproducing device (main part).

[Explanation of symbols]

1 Optical pickup 2 Objective lens 3 Shutter 4 Boss 5 Thread motor 6 Lead screw 7 Spindle motor 8 Turntable 9 RF amplifier 10 DSP 11 Driver 12 DRAM 13 Decoder 14 DAC 15 Speaker

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B 7/12 G11B 7/085 G11B 7/135 G11B 19/02 501

Claims (4)

(57) [Claims] 1. An optical reading means having an objective lens for reading compressed data recorded on a disk, and a shielding member disposed near the objective lens of the optical reading means, wherein a position for covering the objective lens and an objective lens are provided. Shielding means for movably holding the compressed data between a position where the optical reading means is opened, storage means for sequentially storing the compressed data read by the optical reading means, and decoding for sequentially decoding the compressed data stored in the storage means. Means, output means for outputting the data decoded by the decoding means as audio, and, while the decoding means decodes the compressed data read by the optical reading means for a predetermined time and stored in the storage means, Control means for controlling the shielding means to shield the objective lens of the optical reading means. Apparatus. 2. An optical pickup having an objective lens embedded therein and supported movably in a radial direction of a disk by a predetermined guide shaft, and rotatably supported by a rotating shaft erected in contact with the optical pickup. And a motor for moving the optical pickup in the radial direction of the disk; and a stand-up position at the end of the movement of the optical pickup, which abuts on the shutter moved with the optical pickup, and A projection member for rotating; a storage unit for demodulating compressed data read from the disk by the optical pickup and sequentially storing the data; an output unit for outputting digital data as audio; Controlling the motor while the decoding means decodes the compressed data stored in the means. Control means for moving the optical pickup to a standby position and bringing the shutter into contact with the projecting member so as to shield the objective lens of the optical pickup with the rotated shutter. Playback device. 3. A reading means for intermittently reading compressed data recorded on a disk via an optical pickup having an objective lens, a moving means for moving the optical pickup in a radial direction of the disk, and an objective lens included in the optical pickup Placed near
When the optical pickup is carried to the standby position at the end of the movement by the moving means, a shielding member pressed by a predetermined member to shield the objective lens, and the compressed data read by the reading means are sequentially stored. Storage means, output means for demodulating the compressed data stored in the storage means and outputting it as audio, and controlling the moving means to set the optical pickup in a standby position while the reading means stops reading. Move to
Control means for shielding the objective lens of the optical pickup with the shielding member. 4. An optical pickup having an objective lens embedded therein and supported by a guide shaft so as to be movable in the radial direction of the disk, and a shutter rotatably supported by a rotating shaft provided upright in contact with the optical pickup. An object lens shielding method for a disc reproducing apparatus, comprising: a projection member that stands upright at a standby position at the end of the movement of the optical pickup, abuts on a shutter moved together with the optical pickup, and rotates the shutter. Reading compressed data recorded on the disk via the pickup and storing it in a predetermined storage unit; and sequentially decoding the compressed data read from the disk and stored in the storage unit in the compressed data reading step And an optical pickup while the compressed data is decoded in the decoding step. Is moved to the machine position, by the shutter into contact with the projecting member, the objective lens shielding method characterized by and a control step of shielding the objective lens of the optical pickup by turning the shutter.