JP2002245620A - Disk player and discriminating method of kind of disk using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disk player and a discriminating method of the kind of disk using this player, by which the kind of disk is exactly discriminated without improving the performance of a pickup. SOLUTION: The disk 232 such as a DVD or a CD is played back by the disk player 10. In the disk player 10, when the disk 22 is mounted, a DVD mode is set, and a switch SW1 and a switch SW2 are respectively changed over to the side of a decoder 36a and the side of a VCO(voltage control oscillator) 58a. Then, the disk 22 is started in the on-focus state. By an MCU 62, the number of rotation of the disk 22 detected by a DSP(digital signal processor) 40 is monitored, and when the specified number of rotation is attained, the voltage value of the VCO 58a is compared with the prescribed value, then the disk 22 is discriminated as the DVD when the voltage value is higher than the prescribed value, and the disk 22 is discriminated as the CD when the voltage value is equal to or lower than the prescribed value. Consequently, the kind of disk is exactly discriminated without improving the performance of the pickup since the kind of disk is discriminated in accordance with the voltage value of the VCO.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc player and a disc type discriminating method using the disc player, and more particularly to a disc player having a PLL for reproducing a clock based on an RF signal from a pickup, the PLL having a VCO, V
The present invention relates to a disc player that decodes an RF signal using a CO output as a clock and a disc type discriminating method using the same.

[0002]

2. Description of the Related Art An example of a conventional disk player of this type is disclosed in Japanese Patent Application Laid-Open No.
No. 3303053 [G11B 19/12, G11
B 7/09]. This information recording medium discriminating device discriminates at least two types of information recording media having different distances from the surface of the information recording medium to the information recording surface on which the recording information is recorded. In particular,
The objective lens is moved from a predetermined position with respect to the recording medium (disk), and the voltage value of the focus drive when the first focus error signal or the like obtained by the movement appears is detected. Then, the detected focus drive voltage value and the clock time required until the detection are compared with a preset reference voltage and a reference clock time, respectively, and the disc is discriminated as a DVD or a CD from the comparison result. The focus was on the S-shaped signal.

[0003]

However, in this prior art, the voltage value of the focus drive when the first focus error signal or the like appears and the time required for detection are measured, and the disc is DVD or CD. Since the change (S curve) of the voltage value of the focus drive is relatively similar between DVD (single layer) and CD, when the accuracy of the optical pickup is low, the disc The type could not be determined accurately. In order to avoid this, it is conceivable to use a high-performance optical pickup.However, using a high-performance optical pickup only for discriminating the type of the disc is excessive in quality and increases cost only. there were.

[0004] Therefore, a main object of the present invention is to provide a disc player and a disc type discriminating method using the disc player, which can accurately discriminate the disc type without increasing the performance of the pickup. .

[0005]

A first aspect of the present invention is a PL that reproduces a clock based on an RF signal from a pickup.
L is a disk player that has a VCO and decodes an RF signal using a VCO output as a clock, and focus control means for controlling the focus of the pickup, and starts rotation of the disk in a focus-on state A rotation starting unit, a comparing unit for comparing the voltage level of the VCO with a predetermined level when the number of rotations of the disk reaches a certain number of rotations from the start of the disk until the pickup turns on the track, and when the voltage level is larger than the predetermined level. The disc player includes a discriminating means for discriminating the disc as a DVD and discriminating the disc as a CD when the voltage level is equal to or lower than a predetermined level.

The second invention has a PLL for reproducing a clock based on an RF signal from a pickup,
LL has a VCO and uses the VCO output as a clock for RF
A disk player for decoding a signal, focus control means for controlling the focus of the pickup, rotation start means for starting rotation of the disk in a focus on state, and a VCO when the rotation number of the disk reaches a certain rotation number. Is a disc player provided with a discriminating means for discriminating a disc type according to the voltage level of the disc player.

A third invention has a PLL for reproducing a clock based on an RF signal from a pickup,
LL has a VCO and uses the VCO output as a clock for RF
A disc type discriminating method in a disc player for decoding a signal, comprising: (a) focusing on, (b) starting rotation of the disc, and (c) the voltage level of the VCO when the disc reaches a certain number of revolutions. This is a disc type discriminating method for discriminating the disc type according to the type of the disc.

[0008]

[Operation] This disc player is a DVD or CD.
Such a recording medium (disk) can be reproduced. This disk player has a PLL, and uses a VCO output (oscillation frequency signal) included in the PLL as a clock to decode (demodulate) an RF signal read from a recording surface of the disk by a pickup with a decoder. . Here, since the length of the pit is different between the DVD and the CD, when the disk is rotated at the same rotation speed, the data frequency is also different. Therefore, a difference also occurs in the voltage value (voltage level) of the VCO. By utilizing this fact, the type of disc is determined in advance, and DVD and CD
Can be reproduced by an appropriate reproduction circuit. Specifically, when the disc is mounted (replaced), the focus is turned on by the focus control means, and subsequently, the rotation of the disc is started (started) while the focus is turned on by the rotation start means. Then, when the number of rotations of the disk reaches a certain number of rotations from the start of the disk until the pickup is turned on, the comparing means compares the voltage level of the VCO with a predetermined level. When the voltage level is higher than the predetermined level, the discriminating means determines that the disk
D, and when the voltage level is lower than the predetermined level, it is determined that the disk is a CD. in this way,
When the type of the disc is determined, a reproduction mode for the type of disc indicated by the discrimination result is set, and a predetermined process can be performed on the RF signal demodulated by the decoder by an appropriate reproducing circuit.

[0009]

According to the present invention, the disc type is determined based on the voltage value of the VCO, so that the disc type can be accurately determined without improving the performance of the pickup.

Further, since the type of the disc is determined from the start of the disc until the pickup is turned on, there is no need to provide a separate time for the discrimination, and the time until the start of reproduction can be reduced. it can.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a disk player 10 of this embodiment can reproduce a recording medium (disk) 22 such as a DVD or a CD, and
including. The pickup 12 is provided with an objective lens 14. The objective lens 14 is, for example, a bifocal lens type lens.
And the focus actuator 18. The pickup 12 is a laser diode (L
D) The laser light emitted from the LD 20 is converged by the objective lens 14 and irradiated onto the recording surface of the disk 22.

More specifically, when the disk 22 is a DVD, the transmitted light (zero-order light) transmitted through the objective lens 14 is D
When the recording surface of the VD is irradiated and the disk 22 is a CD, the diffracted light (primary light) diffracted by the objective lens 14 is emitted from the CD
The recording surface is irradiated. Therefore, the signal recorded on the disk 22 is read (reproduced).

The disk 22 is mounted on a turntable 26 fixedly provided on a rotation shaft 24 a of a spindle motor 24, and is rotated according to the rotation of the spindle motor 24. In this embodiment, the disk 22 is a CL
This is a V (constant linear velocity) type disk.
(Spindle motor 24)
Decreases from the inner circumference to the outer circumference of the disk 22.

The light reflected from the recording surface passes through the above-described objective lens 14 and irradiates a photodetector 28. The output of the photodetector 28 is output from the RF amplifier 30 to the focus error (F
E) The signal detection circuit 32 and the tracking error (T
E) The signal is input to the signal detection circuit 34.

In the RF amplifier 30, a signal read from the disk 22, that is, an RF signal (reproduction signal) is amplified, and the amplified reproduction signal is supplied to the DV amplifier via the switch SW1.
It is input to the decoders 36a and 36b for D or CD.

Further, the FE signal detection circuit 32 detects the FE signal, the TE signal detection circuit 34 detects the TE signal, and the FE signal and the TE signal are converted into an A / D converter 38a and an A / D converter, respectively. DSP via 38b
Input to 40.

The DSP 40 is a microcomputer unit (MC) that functions as a system control microcomputer.
U) controlling each circuit component under the instruction of 62;
For example, focus servo processing is executed based on the FE signal, and tracking servo processing is executed based on the TE signal.

Specifically, a focus actuator control voltage is generated by the focus servo process, and the generated focus actuator control voltage is applied to the focus actuator 18 via the D / A converter 42a. Further, a tracking actuator control voltage is generated by the tracking servo process, and the generated tracking actuator control voltage is supplied to the tracking actuator 16 via the D / A converter 42b.

That is, the movement (position) of the objective lens 14 in the optical axis direction (focus direction) is controlled by the focus actuator control voltage, and the movement (position) of the objective lens 14 in the radial direction (radial direction of the disk 22) is controlled. , And is controlled by a tracking actuator control voltage.

The DSP 40 generates a sled control voltage by a sled servo process. The sled control voltage is converted into a PWM signal by a drive voltage generation circuit 44 and supplied to a sled motor 46. The rotation speed and the rotation direction of the thread motor 46 are controlled by the PWM signal, and the pickup 12 connected to the rotation shaft (not shown) of the thread motor 46 by a rack and pinion method or a ball screw mechanism is moved in the radial direction (radial direction) of the disk 22. Direction).

The pulse width of the PWM signal output from the drive voltage generation circuit 44 changes according to the sled control voltage.

Further, the DSP 40 generates a rotation control voltage by a rotation servo process, and the rotation control voltage is converted into a PWM signal by a drive voltage generation circuit 48 and supplied to the spindle motor 24. With this PWM signal,
The rotation speed of the spindle motor 24 is controlled.

Note that the pulse width of the PWM signal output from the drive voltage generation circuit 48 changes according to the rotation control voltage.

On the other hand, near the spindle motor 24,
A frequency tachometer (FG) 50 is provided, and generates a rotation pulse (FG pulse) related to the rotation speed of the spindle motor 24. F generated by FG50
The G pulse is input to the DSP 40. That is, DSP
When the spindle motor 24 starts (starts) the rotation, the rotation speed of the spindle motor 24 is detected based on the FG pulse given from the FG 50, and the detected rotation speed is given to the MCU 62. A rotation control voltage is generated so that the motor 24 rotates. Therefore, the CLV type disk 22 can be normally rotated.

In this embodiment, the rotation of the spindle motor 24, that is, the rotation of the disk 22, is controlled based on the FG pulse output from the FG 50.
The rotation of the spindle motor 24 can also be controlled using the output (oscillation frequency signal) of a voltage controlled oscillator (VCO) 58a or VCO 58b provided in a PLL circuit 52 described later.

The reproduced signal output from the RF amplifier 30 is also input to the PLL circuit 52. Specifically, P
The signal is input to one input terminal of a phase comparator 54 included in the LL circuit 52. On the other hand, the other input terminal of the phase comparator 54
VCO 58a, VCO 58b for DVD or CD
The oscillation frequency signal output from the controller is input.

The phase comparator 54 detects a phase difference between the reproduction signal and the oscillation frequency signal, and outputs an output corresponding to the phase difference to the LPF.
Give to 56. The LPF 56 generates a control voltage according to the output from the phase comparator 54. This control voltage is
VCO 58a or VCO 5 via switch SW2
8b and to the MCU 62 via the A / D converter 60.

By such a PLL circuit 52, the phases of the reproduction signal and the oscillation frequency signal are synchronized (locked).

The VCO 58a or VCO 58b
The oscillation frequency signals output from the
VD or CD decoder 36a, decoder 36
b. That is, the decoder 36a demodulates (decodes) the reproduction signal using the oscillation frequency signal supplied from the corresponding VCO 58a as a clock, and the decoder 36b uses the oscillation frequency signal supplied from the corresponding VCO 58b as a clock to reproduce the reproduction signal. To decode.

Since the length of a pit (not shown), that is, the signal recording density differs between a DVD and a CD, the frequency at which a reproduced signal is read also differs. Therefore, VCO
The self-oscillation frequency of 58a becomes higher than the self-oscillation frequency of VCO 58b.

The reproduced signal demodulated by the decoder 36a is subjected to predetermined processing by a DVD reproducing circuit (not shown) at the subsequent stage, and the reproduced signal demodulated by the decoder 36b is subjected to predetermined processing by a CD reproducing circuit (not shown) at the subsequent stage. Is performed.

For example, when the user loads the disk 22 into the disk player 10, the disk 22 is mounted on the turntable 26. In the disk player 10 of this embodiment, a DVD or a CD can be reproduced. As described above, a decoder and a PLL circuit are used for reproducing a DVD (DVD mode) and reproducing a CD (CD mode). Since the reproducing circuit and the like are completely different, it is necessary to determine the type of the disk 22 in advance.

As a method of determining the type of the disk 22, the objective lens 14 is moved from the lowermost position (the uppermost position) to the uppermost position (the lowermost position) with the focus servo turned off (disabled). FE signal detection circuit 3 between
Of the focus error signal obtained in step 2 (S curve)
To determine the type of the disc 22.

However, in a DVD (single layer) and a CD, S
Since the curves are almost the same, it is necessary to use a high-performance pickup 12 in order to accurately determine the type of the disk 22. That is, the cost increases.
In addition, since the type of the disk 22 is determined by moving the objective lens 14 in the focus-off state, the time required to determine the type of the disk 22 becomes longer, and therefore, until the reproduction is started. Takes a long time.

In order to avoid these, in this embodiment,
The control voltage of the LPF 56 as shown in FIG.
VCO 58a with respect to the voltage of VCO 58a and VCO 58b
Utilizing the characteristics of the self-oscillation frequency of the VCO 58b and the time when the pickup 22 is turned on (track-on) on the track (not shown) of the disc 22 after starting up the disc 22, the type of the disc 22 can be accurately determined. Can be determined.

That is, since the pit length is different between the DVD and the CD, when the disk 22 is rotated at the same rotation speed, the data frequency is also different. Therefore, VC
A difference also occurs in the voltage of O58a (or 58b), that is, the control voltage output from the LPF 56. Therefore, during the period from the start of the disk 22 to the time when the pickup 12 turns on the track, the control voltage output from the LPF 56 when the rotation speed of the disk 22 reaches a certain value is detected, and the level of the control voltage is detected. According to the disk 22
Is determined.

More specifically, the MCU 62 shown in FIG. 1 processes according to the flowchart shown in FIG.
Is determined. Disc 2 of disc player 10
When 2 is mounted (replaced), the MCU 62 starts the disc discrimination processing, and sets the DVD mode in step S1. Specifically, the MCU 62 outputs a switching signal and switches the switches SW1 and SW2 to the decoder 36a side and the VCO 58a side, respectively.

Next, in step S3, the LD 20 is turned on,
The recording surface of the disk 22 is irradiated with laser light. continue,
In step S5, the focus servo is turned on (activated).
I do. That is, the MCU 62 instructs the DSP 40 to turn on the focus, and accordingly, the DSP 40 validates the output from the A / D converter 38a. And step S
At 7, the rotation of the disk 22 is started (started). That is, the MCU 62 sends the DSP 40 the spindle motor 24
, And the DSP 40 generates a rotation control voltage in response to the instruction.

In the following step S9, it is determined whether or not the number of revolutions of the disk 22 (spindle motor 24) has reached a constant value (2000 rpm in this embodiment). As described above, the FG pulse output from the FG 50 is D
The DSP 40 calculates the number of revolutions of the spindle motor 24 based on the FG pulse,
Give to 2. Therefore, the MCU 62 can monitor the rotation speed of the disk 22 based on the rotation speed given from the DSP 40, and can determine whether or not the rotation speed has become a constant value.

If "NO" in the step S9, that is, if the rotational speed is less than the predetermined value, the same step S9
And waits until the number of revolutions reaches a constant value. on the other hand,
If “YES” in the step S9, that is, if the rotation speed reaches a constant value, in a step S11, the voltage value of the control voltage of the LPF 56 (the voltage value of the VCO 58a) and a predetermined voltage value (in this embodiment, 0.9 V ) And compare.

The constant value (2000 rpm) and the predetermined voltage value (0.9 V) are values obtained from the characteristics shown in FIG. 2, that is, values obtained in advance by the inventor through experiments and the like. Yes, the ROM 62 provided in the MCU 62
is stored in advance in a.

Also, as shown in FIG.
Is constant (2000 rpm),
If the disc 22 is a DVD, the VCO 58a (or 5
The self-oscillation frequency of 8b) is about 40 MHz, and the control voltage is about 1.2 V at this time. On the other hand, if the disk 22 is a CD, the self-oscillation frequency of the VCO 58b (or 58a) is about 18 MHz, and at this time, the control voltage is about 0.6V.

If "YES" in the step S13, that is, if the voltage value of the VCO 58a is larger than a predetermined voltage value (a predetermined value), it is determined that the disk 22 is a DVD, and the track is turned on in a step S15, and the processing is performed. To end. On the other hand, if “NO” in the step S13, that is, if the voltage value of the VCO 58a is equal to or less than a predetermined value, it is determined that the disk 22 has a CD, and a CD mode is set in a step S17, and then the process proceeds to a step S15. That is, MC
U62 outputs a switching signal in step S17 to switch the switches SW1 and SW2 to the decoder 36b side and the VCO 58b side.

According to this embodiment, since the disc type is determined based on the voltage of the VCO, the disc type can be accurately determined without improving the performance of the pickup.

Further, since the type of the disk can be determined between the time when the disk is started and the time when the objective lens is turned on, there is no need to provide an additional time for determining the type of the disk, and the reproduction can be started. The time until the time can be shortened.

In this embodiment, the fixed value is set to 2000 rpm in step S9, but the present invention is not limited to this. This is because, in the CLV type disk, the rotational speed of the disk decreases as the pickup moves toward the outer periphery of the disk. That is, the relative position between the disk and the pickup at the time of starting the disk is fixed, and the
May be set to a constant value for the number of rotations from the start of the operation until the objective lens 14 turns on the track.

However, in this embodiment, 2000 rpm
Is the number of revolutions corresponding to about 1.5 times speed in DVD.
In the case of a CD, the rotation speed is equivalent to about 4.2 times speed.

In the above embodiment, the DVD mode is set when the disc type discriminating process is started. However, the CD mode can be set.

That is, the MCU 62 executes the disc type discrimination processing according to the flowchart shown in FIG. The flow chart shown in FIG. 4 is different from the flow chart shown in FIG. 3 except that step S17 is provided between the start and step S3, and step S1 is provided between step S13 and step S15. 3 is substantially the same as the flowchart of FIG.

As shown in FIG. 4, when the disk 22 is mounted (replaced), the MCU 62 starts processing and sets the CD mode in step S17. That is, MCU62
Outputs a switching signal, and switches the switches SW1 and SW2 to the decoder 36b side and the VCO5, respectively.
Switch to 8b side.

Further, the MCU 62 sets V in step S11.
The voltage value of CO58b is compared with a predetermined value, and step S1 is performed.
At 3, it is determined whether the voltage value of the VCO 58b is larger than a predetermined value. If "YES" in the step S13, it is determined that the disk 22 is a DVD, and
After the D mode is set, that is, the switches SW1 and SW2 are switched to the decoder 36a side and the VCO 58a side, respectively, and then the process proceeds to step S15. On the other hand, if “NO” in the step S13, it is determined that the disk 22 is a CD, and the process directly proceeds to a step S15.

Further, in the disk player 10, when the disk 22 is mounted (replaced), the reproduction mode (DVD) corresponding to the type of the disk 22 reproduced immediately before is set.
Mode or the CD mode), the disc determination process can be executed without setting the DVD mode or the CD mode in the first step.

That is, the MCU 62 executes the disc type discriminating process according to the flowchart shown in FIG. Note that the flowchart shown in FIG. 5 is the same as the flowchart of FIG. 3 except that step S1 of the flowchart shown in FIG. 3 is provided between step S13 and step S15. Description is omitted.

Specifically, "YES" in step S13
If it is determined that the disc 22 is a DVD, the DVD mode is set in step S1, that is, the switches SW1 and SW2 are switched to the decoder 36a side and the VCO 58a side, respectively, and then the process proceeds to step S15. On the other hand, “NO” in the step S13
If it is determined that the disc 22 is a CD, the CD mode is set in step S17, that is, the switches SW1 and SW2 are switched to the decoder 36b side and the VCO 58b side, respectively, and then the process proceeds to step S15.

Further, in the above embodiment, the LPF 5
6 is supplied to the MCU 62 via the A / D converter 60, and the MCU 62 compares the voltage value of the control voltage, that is, the voltage value of the VCO 58a or VCO 58b with a predetermined value. A comparator 64 may be provided instead of the converter 60, and the result of the comparison may be provided to the MCU 62.

That is, the disc player 10 is configured as shown in FIG. The disc player 10 of FIG. 6 is substantially the same as the disc player 10 shown in the embodiment of FIG.

In the disc player 10 shown in FIG. 6, the comparator 64 compares the control voltage output from the LPF 56 with a constant voltage _Vref corresponding to the predetermined value in the above-described embodiment. When the control voltage is higher than the predetermined value (V _ref ), a high-level signal is output. When the control voltage is lower than the predetermined value (V _ref ), a low-level signal is output.

Therefore, when the comparator 64 is provided, the MCU 62 determines the type of the disk 22 in step S13 according to whether the level of the signal output from the comparator 64 is high or not. I just need.

[Brief description of the drawings]

FIG. 1 is an illustrative view showing a configuration of an embodiment of the present invention;

FIG. 2 shows V with respect to the control voltage of the LPF shown in FIG. 1 embodiment.
FIG. 4 is an illustrative view showing characteristics of a self-oscillation frequency of CO;

FIG. 3 is a flowchart showing disc type discrimination processing of the MCU shown in FIG. 1 embodiment.

FIG. 4 is a flowchart showing a disc type discrimination process of an MCU according to another embodiment.

FIG. 5 is a flowchart showing a disc type discrimination process of an MCU according to another embodiment.

FIG. 6 is an illustrative view showing a configuration of one embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Disc player 12 ... Pickup 14 ... Objective lens 22 ... Disk 24 ... Spindle motor 30 ... RF amplifier 32 ... FE signal detection circuit 34 ... TE signal detection circuit 36a, 36b ... Decoder 40 ... DSP 52 ... PLL circuit 54 ... Phase comparison Containers 58a, 58b ... VCO 62 ... MCU

Claims (6)

[Claims] 1. A disk player having a PLL for reproducing a clock based on an RF signal from a pickup, the PLL having a VCO, and decoding an RF signal using a VCO output as a clock. Focus control means for controlling the rotation of the disk in a focus-on state, when the rotation speed of the disk reaches a certain rotation speed from the start of the disk until the pickup turns on the track, Comparing means for comparing the voltage level of the VCO with a predetermined level; and discriminating the disc as a DVD when the voltage level is higher than the predetermined level, and discriminating the disc as a CD when the voltage level is lower than the predetermined level. A disc player, comprising: 2. A disk player having a PLL for reproducing a clock based on an RF signal from a pickup, the PLL having a VCO, and decoding an RF signal using a VCO output as a clock. A focus control unit for controlling the rotation of the disk in a focus-on state, and a type of the disk according to the voltage level of the VCO when the rotation speed of the disk reaches a certain rotation speed. A disc player comprising a discriminating means for discriminating. 3. The disk player according to claim 2, wherein said constant rotation speed is set to a rotation speed from the start of said disk until said pickup is turned on. 4. A comparison means for comparing the voltage level with a predetermined level, wherein the determination means determines that the disk is a DVD when the voltage level is higher than the predetermined level, and determines that the voltage level is equal to the predetermined level. When the level is below the level,
The disc player according to claim 2, wherein the disc player determines that the disc is D. 5. 5. A disc type discriminating method for a disc player which has a PLL for reproducing a clock based on an RF signal from a pickup, has a VCO, and decodes an RF signal using a VCO output as a clock. (A) focus on, (b) start rotation of the disk, and (c) determine the type of the disk according to the voltage level of the VCO when the disk reaches a certain number of rotations. Method. 6. The step (c) includes a step (c-1) of comparing the voltage level with a predetermined level. If the result of the comparison is that the voltage level is higher than the predetermined level, the disc is set to a DVD. 6. The disc type discriminating method according to claim 5, wherein the disc is discriminated as a CD when the voltage level is equal to or lower than the predetermined level.