JP4483859B2 - Information recording / reproducing device - Google Patents

Description

  The present invention relates to an information recording / reproducing apparatus using an optical disk, and more particularly to an information recording / reproducing apparatus provided with means for discriminating the type of an optical disk and controlling the reproduction laser power.

  In recent years, many information recording / reproducing apparatuses using an optical disk as a recording medium can use various types of optical disks in one apparatus. As the types of optical discs, for example, DVDs (Digital Versatile Discs) include one-layer and two-layer discs for reproduction only, DVD-R (DVD-Recordable) one-layer and two-layer discs that can be recorded only once, There are DVD-RW (DVD-Rewritable) single-layer and double-layer discs that can be rewritten many times, DVD-RAM (Random Access Memory) in another rewritable format, and the like. Furthermore, there are DVD + R that can be recorded only once and DVD + RW that can be rewritten, which have different specifications. Recently, a multilayer disc having three or more reflective layers as well as the above two layers has been proposed.

Other optical discs include CD (Compact Disc), BD (Blu-Ray), HD DVD (High Definition DVD), etc., whose recording capacity is significantly different from DVD, and these optical discs can also be used. There are multifunctional recording and playback devices.
In an information recording / reproducing apparatus that performs recording / reproduction using such various optical discs, it is possible to determine in a short time what type of optical disc is newly loaded on the disc tray and to determine the specifications of the disc It is desired that the setting can be quickly switched to the setting according to the condition.

  Immediately after the optical disc is loaded in the disc tray, the setting is not suitable for the disc, so that the optical pickup cannot reproduce the signal recorded from the optical disc and read the disc type. Therefore, as a method of discriminating the type of the optical disk at this point, a light beam is irradiated on the reflection layer of the optical disk, and the reflected return light is detected as an electric signal by a photodetector, and the characteristics of the detected signal Many methods for discriminating types have been conventionally employed (see, for example, Patent Document 1).

First, a conventional method for discriminating optical disks will be briefly described.
Optical discs have a reflective layer on which information is recorded and a transparent substrate formed on the reflective layer, and are classified into various types depending on the thickness of the transparent substrate and the physical characteristics of the reflective layer. Therefore, a method of discriminating the disc by detecting the difference between the thickness of the transparent substrate and the physical characteristics of the reflective layer is used. Specifically, the objective lens for condensing the light beam is moved in the optical axis direction toward the surface of the optical disc, and the level of the detection signal of the reflected light obtained at that time is discriminated.

First, in order to determine the thickness of the transparent substrate, the objective lens is moved toward the optical disc at a predetermined constant speed in the direction of the optical axis, and the reflected light generated at the position where the light beam is focused on the transparent substrate surface. Discriminate the detection signal that increases the intensity, further advance the objective lens, then discriminate the detection signal that increases the intensity of the reflected light generated at the position where the light beam is focused on the reflective layer. The thickness of the transparent layer is determined from the travel time of the objective lens. At this time, the objective lens is further advanced, and when a reflective layer is detected at two locations, it is determined that the disc is a double-layer disc. Further, physical characteristics such as reflectance of the reflective layer are discriminated from the detection signal level of the reflected light when the light beam is focused on the reflective layer, and the type of the optical disc is specified from these discrimination results.
By making various settings according to the type of optical disc specified in this way, it becomes possible to read out signals from the optical disc. Therefore, in the next stage, the disc information recorded on the disc is reproduced to determine the exact disc type. Can be confirmed.

On the other hand, a semiconductor laser that generates a light beam that irradiates an optical disk is a so-called scoop that generates abnormal noise in the emitted light beam when reflected light from the optical disk returns to the semiconductor laser that is the light source during signal readout. There is a phenomenon called noise, which causes a problem that noise enters the reproduction signal and causes a read error.
As means for reducing the scoop noise, a method of emitting light in a state where a high frequency signal is superimposed on a driving signal for emitting a semiconductor laser and a light beam is superimposed on a high frequency is widely used (for example, Patent Document 2). reference).
JP-A-11-283319 JP 2002-335041 A

  In the conventional method of discriminating the disc using the return light reflected by the optical disc, the return light detection signal is caused by various factors such as disc scratches, dirt, surface blurring, eccentricity, power fluctuation of the semiconductor laser, temperature characteristic change, etc. Has deteriorated and often has a drawback of erroneous disc identification.

  In general, a multi-layer disk such as a DVD-RW double-layer disk has a low light beam reflectivity in the reflective layer. Therefore, when a recorded signal is read out, the reproduction laser power is increased and a strong light beam is applied. For this reason, for example, when a rewritable single-layer disc is mistakenly identified as a rewritable double-layer disc, a single-layer disc is irradiated with a light beam having a high reproduction laser power. Will occur. At this time, if a high frequency signal is superimposed on the driving signal of the semiconductor laser for the purpose of reducing the scoop noise, a light beam with higher power is generated at the waveform peak point of the superimposed high frequency signal. In the rewritable single-layer disc irradiated with, there is a problem that the recorded part is erroneously erased.

  The present invention has been made in view of the above-described problems of the related art, and a rewritable single-layer disc can be rewritable by discriminating the type of the optical disc by detecting return light reflected by the optical disc. An information recording / reproducing apparatus that does not cause erroneous erasure of an already recorded portion even when it is erroneously determined as an optical disc that requires a high setting of the reproducing laser power as described above. And

The present invention includes the following configurations (1) and (2) as means for solving the above-described problems. That is,
(1) In an information recording / reproducing apparatus capable of recording / reproducing plural types of optical discs,
A semiconductor laser that emits a laser beam that irradiates the optical disc; and an objective lens that condenses the laser beam on the optical disc. The return light reflected by the optical disc is detected, and an information signal and a servo are detected from the detection result. An optical pickup to get the signal,
Disc discriminating means for discriminating the type of the optical disc from the servo signal detected by the return light of the optical disc by moving the objective lens along its optical axis;
The semiconductor laser is driven with a high-frequency signal superimposed thereon, and the reproduction laser power of the semiconductor laser is controlled to an intensity corresponding to the disc type of the discrimination result of the disc discriminating means, and then the disc type data read from the optical disc Power control means for controlling the intensity of the reproduction laser power of the semiconductor laser according to
In the case of a rewritable multilayer disc in which both the type of the optical disc recorded in the lead-in area of the optical disc and the discrimination result of the disc discrimination means are the same, without controlling the intensity of the reproduction laser power in the power control means performs control for the superposition of the high frequency signal to the on-when the determination result of the type and the disc discrimination means of the optical disk recorded in the lead-in area of the optical disc is not the same rewritable multilayer disks, the optical disk in response to the disc type of the data recorded in the re Doin'eria, the control to decrease the intensity of the reproducing laser power in the power control unit, at the same time, the high-frequency superposition control means for controlling to turn on the superposition of the high frequency signal When,
An information recording / reproducing apparatus is provided.
(2) In an information recording / reproducing apparatus capable of recording / reproducing plural types of optical discs,
A semiconductor laser that emits a laser beam that irradiates the optical disc; and an objective lens that focuses the laser beam on the optical disc. The return light reflected by the optical disc is detected, and an information signal and a servo are detected from the detection result. An optical pickup to get the signal,
Disc discriminating means for discriminating the type of the optical disc from the servo signal detected by the return light of the optical disc by moving the objective lens along its optical axis;
The semiconductor laser is driven with a high-frequency signal superimposed thereon, and the reproduction laser power of the semiconductor laser is controlled to an intensity corresponding to the disc type of the discrimination result of the disc discriminating means, and then the disc type data read from the optical disc Power control means for controlling the intensity of the reproduction laser power of the semiconductor laser according to
In the case of a rewritable multilayer disc in which the discriminating result of the disc discriminating means is rewritable, the rotational speed of the optical disc is set to a rotational speed higher than a predetermined rotational speed, and then the power control means changes the reproduction laser power of the semiconductor laser to the optical disc. A rotational speed control means for returning the rotational speed of the optical disk to a predetermined rotational speed after controlling the intensity according to the disc type data read from the lead-in area;
An information recording / reproducing apparatus is provided.

According to the first aspect of the present invention, in disc discrimination using return light reflected from the optical disc, a rewritable single-layer disc is erroneously discriminated as a multi-layer disc, and the emission power of the reproduction laser beam for signal reading is increased. Even if the setting is made, the superposition of the high frequency signal applied to the semiconductor laser is turned off until the disc type data recorded in the lead-in area of the optical disc can be subsequently read. It is possible to avoid the problem of erroneously erasing already recorded data due to the fact that the superimposition of is turned on.
Further, in the configuration of claim 2, the rewritable single-layer disc is erroneously discriminated as a multi-layer disc in the same manner as described above, the reproduction laser power is set high, and even when a high frequency signal is superimposed, the optical disc is subsequently Until the data of the disc type recorded in the lead-in area can be read, the irradiation time per unit area of the emission power of the reproduction laser beam on which the high-frequency signal is superimposed by increasing the number of revolutions of the optical disc Therefore, the recorded data is not erased and the conventional problem of erroneously erasing the recorded data can be avoided. Furthermore, since the scoop noise is reduced by superimposing the high-frequency signal on the reproduction laser beam, it is easy to read the data in the lead-in area.

An information recording / reproducing apparatus according to an embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing an embodiment of an information recording / reproducing apparatus according to the present invention. FIG. 2 is a flowchart for explaining the operation of the first embodiment of the information recording / reproducing apparatus shown in FIG. FIG. 3 is a flowchart for explaining the operation of the second embodiment of the information recording / reproducing apparatus shown in FIG.

First, the configuration of the information recording / reproducing apparatus according to the present invention will be described with reference to FIG.
The optical disk used below is a rewritable single-layer or multi-layer optical disk, and has a lead-in area in which data indicating the type of the disk is recorded.
The information recording / reproducing apparatus 1 records or records information on a spindle motor 5 that rotates a detachable optical disk 4 loaded on a disk tray (not shown), a rotation speed control unit 14 that controls the rotation of the spindle motor 5, and an optical disk 4. An optical pickup 6 for reproducing an optical disc 4 to obtain information signals and servo signals (tracking error signal and focus error signal), an amplifier 10 for amplifying information signals and servo signals obtained by reproducing with the optical pickup 6, and an amplifier 10 includes a signal processing unit 11 that binarizes the information signal amplified in 10 and a decoder 12 that decodes each signal binarized by the signal processing unit 11.

  Furthermore, the information recording / reproducing apparatus 1 temporarily stores the signal decoded by the decoder 12 or temporarily stores data for recording on the optical disk 4 and the servo signal amplified by the amplifier 10. Based on the servo unit 15 that controls the optical pickup 6, the disc determination unit 16 that discriminates the type of the disc of the optical disc 4 based on the information signal and the servo signal amplified by the amplifier 10, and the whole of the above-described units. It is comprised from CPU17 which performs control.

Furthermore, the information recording / reproducing apparatus 1 includes an encoder 9 for encoding data for recording on the optical disk 4 temporarily stored in the data buffer 13, and an optical pickup 6 based on the encoded signal encoded by the encoder 9. A power control unit 8 that controls the power of laser light emitted from the semiconductor laser (not shown) and generates a high-frequency signal to be superimposed on the laser light, and a semiconductor laser (not shown) that generates the high-frequency signal generated by the power control unit 8 ) And a high frequency superimposing control unit 7 for outputting a selection signal as to whether or not to superimpose on the laser light emitted from.
The input / output signal of the information recording / reproducing apparatus 1 is connected to an external device through the input / output control unit 2 through the input / output terminal 3.

Next, a first embodiment of the information recording / reproducing apparatus 1 according to the present invention will be described with reference to FIG.
FIG. 2 shows the steps of the operation necessary from when the optical disc 4 is newly loaded into the disc tray until the disc discrimination and activation processing is completed.
First, when the optical disk 4 is newly loaded on the disk tray, the rotational speed control unit 14, the servo unit 15, the amplifier 10, the signal processing unit 11, the data buffer 13, the power control unit 8, the disk determination unit 16, and the CPU 17 are set in advance. A predetermined initial value is set (step S1).

  Next, the spindle motor 5 is rotated at a predetermined rotation speed under the control of the rotation speed control unit 14, and at the same time, a control signal is output from the power control unit 8 to emit laser light from a semiconductor laser (not shown) in the optical pickup 6. Is emitted. Next, a control signal is output from the servo unit 15 to the optical pickup 6, and an objective lens (not shown) in the optical pickup 6 is moved toward the optical disk 4.

Laser light emitted from a semiconductor laser (not shown) in the optical pickup 6 is applied to the reflective layer of the optical disc 4, and the return light reflected here is detected by a photodetector (not shown) in the optical pickup 6. Here, a focus signal is obtained from the detection signal photoelectrically converted and amplified by the amplifier 10. Based on the focus signal amplified by the amplifier 10, the disc discriminating unit 16 calculates the thickness of the transparent substrate of the optical disc 4, the number of reflecting layers, and physical characteristics using the conventional disc discriminating method described above. The type is determined (step S2).
Next, the CPU 17 determines whether or not the disk determination result of the disk determination unit 16 is a rewritable multilayer disk (step S3).

  When it is determined in step S3 that the disc discrimination result is a rewritable multilayer disc, the high frequency superimposing control unit 7 outputs a control signal for turning off the high frequency signal superimposed on the laser light to the power control unit 8. To do. The power control unit 8 turns off the superposition of the high-frequency signal of the laser beam by the control signal from the high-frequency superposition control unit 7, and at the same time, the laser beam emission power reaches a predetermined intensity determined by the recordable multilayer disk. A semiconductor laser (not shown) in the optical pickup 6 is controlled to rise. (Step S4).

  Next, under the control of the servo unit 15, servo adjustment is performed so that the optical pickup 6 is set to a predetermined setting according to the rewritable multilayer disk (step S6).

  Next, the control data or the prepit physical data in the lead-in area of the optical disk 4 is reproduced by the optical pickup 6, and the disk type data recorded in this data and the above-mentioned disk discriminating section 16 are used to reproduce the optical disk by the CPU 17. The disc type is compared with the result of discriminating the rewritable multi-layer disc to determine whether or not the disc types match (step S7).

  Next, when the disc type data recorded in the lead-in area matches the disc type as a result of disc discrimination in the determination in step S7, the high frequency superimposing control unit 7 outputs a high frequency signal to be superimposed on the laser beam. A control signal to turn on is output to the power control unit 8, and the power control unit 8 emits a laser beam from a semiconductor laser (not shown) so that the high frequency signal is superimposed by the control signal from the high frequency superposition control unit 7. The light is controlled (step S8).

  Next, the signal processing unit 11 performs signal adjustment so as to obtain a predetermined setting corresponding to the disc type, and further reads defect management information from the lead-in area of the optical disc 4 and stores it in the data buffer 13. In this way, the start-up process including discriminating the type of the optical disc is ended, and the optical disc 4 is set in a recording / reproducing standby state (step S11).

On the other hand, if the disc type data recorded in the lead-in area and the disc type according to the disc discrimination result do not match in the determination in step S7, the power control unit 8 switches to a semiconductor laser (not shown). A control signal is output, the emission power of the semiconductor laser is lowered to the reproduction power corresponding to the disc type data recorded in the lead-in area, and at the same time, the laser beam is emitted from the semiconductor laser by the control signal from the high-frequency superposition control unit 7 The high frequency signal superimposition of the laser beam to be performed is turned on (step S9).
Next, servo adjustment is performed by the servo unit 15 so that the optical pickup 6 has a predetermined setting corresponding to the disc type recorded in the lead-in area (step S10).
Next, the same operation as the above-described step S11 is performed, and the optical disk 4 is set in a recording / reproducing standby state.

If the disc discrimination result in step S3 is not a rewritable multilayer disc, the high frequency superimposing control unit 7 sends a control signal for turning on the high frequency signal superimposed on the laser light to the power control unit 8. The power control unit 8 turns on the superposition of the high-frequency signal of the laser beam by the control signal from the high-frequency superposition control unit 7 and determines a predetermined value corresponding to the disc determined as other than the multi-layer disc that can rewrite the light emission power. The semiconductor laser (not shown) in the optical pickup 6 is controlled so as to emit light with the reproduction power of (step S5).
Next, in step S6, a predetermined servo adjustment is performed according to the disc determined as other than the rewritable multilayer disc by the servo unit 15.

  Next, in step S7, the lead-in area of the optical disc 4 is reproduced by the optical pickup 6 servo-adjusted based on the disc discrimination result, the disc type data recorded in the lead-in area and the disc discrimination result. Are matched, and if they match, in the same manner as described above, in step S8, the control signal from the high frequency superimposing control unit 7 is output to the power control unit 8 to superimpose the high frequency signal of the laser beam. Is turned on, and the optical disk 4 is set in a recording / reproducing standby state through step S11.

If it is determined in step S7 that the disc determination result does not match the disc type data recorded in the lead-in area of the optical disc 4, in step S9, the power control unit 8 A control signal is output to a semiconductor laser (not shown), and the emission power corresponding to the disc type data recorded in the lead-in area of the optical disc 4 is output from the semiconductor laser. A signal is output to the power control unit 8 to turn on high-frequency signal superimposition of the laser beam.
Subsequently, in step S10, the servo unit 15 again adjusts the servo so that the optical pickup 6 has a predetermined setting corresponding to the data of the disk type recorded in the lead-in area, and then passes the optical disk through step S11. 4 is set to the recording / reproducing standby state.

  As described above in detail, according to the first embodiment of the information recording / reproducing apparatus of the present invention, when the optical disc type discrimination is rewritable with a multi-layer disc, the error and the emission power output from the semiconductor laser are set high. However, the high-frequency signal to be applied to the semiconductor laser is not processed until the reading of the disc type data recorded in the lead-in area of the optical disc 4 is completed and the light emission power is set according to the read disc type data. Is turned off, so that erroneous erasure of recorded data due to the superposition of the conventional high-frequency signal can be prevented.

Next, a second embodiment of the information recording / reproducing apparatus 1 according to the present invention will be described with reference to FIG.
FIG. 3 shows the operation steps in the second embodiment which are necessary from the time when the optical disk 4 is newly loaded into the disk tray until the disk discrimination and activation processing is completed.
The second embodiment is the same as the configuration of the information recording / reproducing apparatus of the first embodiment, but the operation method is different. That is, the rotation speed of the optical disk 4 is increased until reading of the disc type data recorded in the lead-in area of the optical disk 4 and the unit area of the laser beam on which the high-frequency signal irradiated to the optical disk 4 is superimposed is increased. This is the same as the rest.
Similar to the first embodiment, when the optical disk 4 is newly loaded in the disk tray, the rotation speed control unit 14, the servo unit 15, the amplifier 10, the signal processing unit 11, the data buffer 13, the power control unit 8, and the disk The determination unit 16 and the CPU 17 are set to predetermined initial values (step S21).

  Next, the spindle motor 5 is rotated at a predetermined rotation speed under the control of the rotation speed control unit 14, and at the same time, a control signal is output from the power control unit 8 to emit laser light from a semiconductor laser (not shown) in the optical pickup 6. Is emitted. Next, a control signal is output from the servo unit 15 to the optical pickup 6, and an objective lens (not shown) in the optical pickup 6 is moved toward the optical disk 4.

Laser light emitted from a semiconductor laser (not shown) in the optical pickup 6 is applied to the reflective layer of the optical disc 4, and the return light reflected here is detected by a photodetector (not shown) in the optical pickup 6. Here, a focus signal is obtained from the detection signal photoelectrically converted and amplified by the amplifier 10. Based on the focus signal amplified by the amplifier 10, the disc discriminating unit 16 calculates the thickness of the transparent substrate of the optical disc 4, the number of reflecting layers, and physical characteristics using the conventional disc discriminating method described above. The type is determined (step S22).
Next, the CPU 17 determines whether or not the disk determination result of the disk determination unit 16 is a rewritable multilayer disk (step S23).

  If it is determined in step S23 that the disc discrimination result is a rewritable multilayer disc, the power control unit 8 outputs a high-frequency signal to be superimposed on the laser beam emitted from the semiconductor laser (not shown). The light emission power of the laser light is increased to a predetermined intensity determined by the rewritable multilayer disk, and the rotation speed of the spindle motor 5 is increased to a predetermined high rotation speed by the control of the rotation speed control unit 14. (Step S24).

  Next, under the control of the servo unit 15, servo adjustment is performed so that the optical pickup 6 has a predetermined setting corresponding to the rewritable multilayer disk (step S25).

  Next, the control data or the prepit physical data in the lead-in area of the optical disk 4 is reproduced by the optical pickup 6, and the disk type data recorded in this data and the above-mentioned disk discriminating section 16 are used to reproduce the optical disk by the CPU 17. The disc type is compared with the result of discriminating the rewritable multi-layer disc to determine whether or not the disc types match (step S26).

  Next, when the disc type data recorded in the lead-in area matches the disc type as a result of disc discrimination in the determination in step S26, the rotation of the spindle motor 5 is controlled by the rotation speed control unit 14. The number is returned from the high-speed rotation to the predetermined rotation number (step S27), and then the servo adjustment is performed again by the control of the servo unit 15 so that the optical pickup 6 becomes a predetermined setting corresponding to the rewritable multilayer disk (step S27). Step S28).

  Next, the signal processing unit 11 performs signal adjustment so as to obtain a predetermined setting according to the disc type, and further reads defect management information from the lead-in area of the optical disc 4 and stores it in the data buffer 13. In this way, the start-up process including discriminating the type of the optical disc is ended, and the optical disc 4 is set in a recording / reproducing standby state (step S29).

  On the other hand, if the disc type data recorded in the lead-in area does not match the disc type as a result of disc discrimination described above in step S26, the power control unit 8 switches to a semiconductor laser (not shown). A control signal is output, and the emission power of the semiconductor laser is lowered to the reproduction power corresponding to the disc type data recorded in the lead-in area (step S30). Next, in the same manner as described above, in step S27, the rotational speed of the optical disk is returned from the high speed to a predetermined rotational speed by the control of the rotational speed control unit 14, and then in step S28, the optical pickup 6 is read by the servo unit 15. Servo adjustment is performed so as to obtain a predetermined setting according to the disc type recorded in the in-area.

  Next, in step S29, the signal processing unit 11 performs signal adjustment so as to obtain a predetermined setting corresponding to the disc type, and further reads defect management information from the lead-in area of the optical disc 4 and stores it in the data buffer 13. In this way, the start-up process including discriminating the type of the optical disc is ended, and the optical disc 4 is put into a recording / reproducing standby state.

If the disc discrimination result in step S23 is not a rewritable multilayer disc, a control signal can be output from the power control unit 8 to the semiconductor laser (not shown) to rewrite the emission power of the semiconductor laser. set to a predetermined reproduction power in accordance with the disk is discriminated as a non-multi-layer disc, the rotational speed of the optical disc 4 at a predetermined rotation number by the control of the rotation speed control unit 14 simultaneously (step S31).

Next, predetermined servo adjustment is performed according to the disc determined as other than the rewritable multilayer disc by the servo unit 15 (step S32).
Next, the lead-in area of the optical disc 4 is reproduced by the optical pickup 6 servo-adjusted based on the disc discrimination result, and the disc type data recorded in the lead-in area matches the disc discrimination result. (Step S33), and if they match, in step S29, the recording / reproduction standby state is set as described above.

If it is determined in step S33 that the disc discrimination result does not match the disc type data recorded in the lead-in area of the optical disc 4, the power control unit 8 sends a control signal to the semiconductor laser (not shown). And the emission power corresponding to the disc type data recorded in the lead-in area of the optical disc 4 is outputted from the semiconductor laser (step S34).
Subsequently, in step S28, the servo unit 15 again adjusts the servo so that the optical pickup 6 has a predetermined setting corresponding to the disc type data recorded in the lead-in area, and then starts through step S29. The processing is terminated, and the optical disk 4 is set in a recording / reproducing standby state.

  As described above in detail, according to the second embodiment of the information recording / reproducing apparatus of the present invention, the rewritable multi-layer disc and the error, the emission power output from the semiconductor laser is set high. Even when the high-frequency signal is superimposed, the reading of the optical disc type data recorded in the lead-in area of the optical disc 4 is completed and the light emission power is set according to the read disc type data. Since the irradiation time per unit area of the reproduction laser power on which the high frequency signal is superimposed is shortened by increasing the number of revolutions of the disk 4, the existing recording due to the superposition of the conventional high frequency signal is performed. Data erasure can be prevented.

Further, in the second embodiment, since the high frequency signal is superimposed on the laser beam when reading the disc type data recorded in the lead-in area, the scoop noise is reduced and the data can be read with less errors. Has characteristics.
However, in the second embodiment, since an operation for changing the rotational speed of the optical disk 4 is performed, there is a drawback that the time until the recording / reproducing standby state is reached is delayed. For this reason, the operation of the first embodiment is normally performed, and the operation of switching to the second embodiment is performed when an optical disc is loaded so that the lead-in area cannot be read even after a predetermined time has elapsed in the first embodiment. This increases the possibility of reading the data in the lead-in area and improves the reliability of disc discrimination.

It is a block diagram which shows one Example of the information recording / reproducing apparatus which concerns on this invention. 3 is a flowchart for explaining the operation of the first embodiment of the information recording / reproducing apparatus shown in FIG. It is a flowchart explaining the operation | movement of 2nd Example of the information recording / reproducing apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Information recording / reproducing apparatus 2 ... Input / output control part 3 ... Input / output terminal 4 ... Optical disk 5 ... Spindle motor 6 ... Optical pick-up 7 ... High frequency superimposition control part (high frequency superimposition control means)
8. Power control unit (power control means)
DESCRIPTION OF SYMBOLS 9 ... Encoder 10 ... Amplifier 11 ... Signal processing part 12 ... Decoder 13 ... Data buffer 14 ... Revolution speed control part (revolution speed control means)
15 ... Servo unit 16 ... Disc discriminating unit (disc discriminating means)
17 ... CPU

Claims (2)

In an information recording / reproducing apparatus capable of recording / reproducing plural types of optical discs,
A semiconductor laser that emits a laser beam that irradiates the optical disc; and an objective lens that condenses the laser beam on the optical disc. The return light reflected by the optical disc is detected, and an information signal and a servo are detected from the detection result. An optical pickup to get the signal,
Disc discriminating means for discriminating the type of the optical disc from the servo signal detected by the return light of the optical disc by moving the objective lens along its optical axis;
The semiconductor laser is driven with a high-frequency signal superimposed thereon, and the reproduction laser power of the semiconductor laser is controlled to an intensity corresponding to the disc type of the discrimination result of the disc discriminating means, and then the disc type data read from the optical disc Power control means for controlling the intensity of the reproduction laser power of the semiconductor laser according to
In the case of a rewritable multilayer disc in which both the type of the optical disc recorded in the lead-in area of the optical disc and the discrimination result of the disc discrimination means are the same, without controlling the intensity of the reproduction laser power in the power control means performs control for the superposition of the high frequency signal to the on-when the determination result of the type and the disc discrimination means of the optical disk recorded in the lead-in area of the optical disc is not the same rewritable multilayer disks, the optical disk in response to the disc type of the data recorded in the re Doin'eria, the control to decrease the intensity of the reproducing laser power in the power control unit, at the same time, the high-frequency superposition control means for controlling to turn on the superposition of the high frequency signal When,
An information recording / reproducing apparatus comprising: In an information recording / reproducing apparatus capable of recording / reproducing plural types of optical discs,
A semiconductor laser that emits a laser beam that irradiates the optical disc; and an objective lens that condenses the laser beam on the optical disc. The return light reflected by the optical disc is detected, and an information signal and a servo are detected from the detection result. An optical pickup to get the signal,
Disc discriminating means for discriminating the type of the optical disc from the servo signal detected by the return light of the optical disc by moving the objective lens along its optical axis;
The semiconductor laser is driven with a high-frequency signal superimposed thereon, and the reproduction laser power of the semiconductor laser is controlled to an intensity corresponding to the disc type of the discrimination result of the disc discriminating means, and then the disc type data read from the optical disc Power control means for controlling the intensity of the reproduction laser power of the semiconductor laser according to
In the case of a rewritable multilayer disc in which the discriminating result of the disc discriminating means is rewritable, the rotational speed of the optical disc is set to a rotational speed higher than a predetermined rotational speed, and then the power control means sets the reproduction laser power of the semiconductor laser to the optical disc. A rotational speed control means for returning the rotational speed of the optical disk to a predetermined rotational speed after controlling the intensity according to the data of the disk type read from the lead-in area;
An information recording / reproducing apparatus comprising:

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