JPH0917106A - Disk discriminating apparatus - Google Patents

Abstract

PURPOSE: To discriminate the kind of a disk aunomatically. CONSTITUTION: Detected signals SA1-SF1 outputted from the optical pickup (not shown in the figure) of a disk player are synthesized and amplified in a broad-band amplifier 91. The output is converted into the DC by an envelope detector 92. The output of the envelope detector 92 is compared with a reference level in a level comparator 93, and the 'high' and 'low' pulses are formed. Then, in a track-pitch detector 94, the moving distance per unit time of the optical pickup moving at a constant speed is divided by the number of the 'highs' per unit time. Thus, the track pitch or the disk is computed. In a disk- kind discriminating device 95, the kind of the disk is discriminated based on the computed track pitch. That is, when the track pitch is, e.g. 1.2μm, it is judged that this disk is CD, and when the track pitch is 0.6μm, it is judged that the disk is DVD.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc discriminating apparatus capable of discriminating discs having different recording formats. More specifically, the present invention relates to a disc discriminating apparatus that discriminates the type of disc based on the track pitch of the disc.

[0002]

2. Description of the Related Art Compact discs (CD, CD-
Compact) for playing G) and video CDs (V-CDs)
As is well known, a disc player optically reads a digital audio signal recorded on a compact disc (hereinafter referred to as a CD) or a video or audio digital signal compressed by digital processing to obtain a high quality audio signal. Signals and video signals can be reproduced.

On the other hand, the recently developed digital video disc (hereinafter referred to as DVD) is a step ahead of the video CD, and the storage capacity at present is about 6 to 8 times that of the video CD. CD and DVD have an outer diameter of 12 cm
However, the recording format is different. For example, C
The track pitch of D is 1.2 μm, but the track pitch of DVD is 0.6 μm. This is due to the difference in storage capacity.

Therefore, it is not possible to use the same optical pickup for reproducing a CD and an optical pickup for reproducing a DVD. Therefore, a DVD player can reproduce a DVD or, conversely, a DVD player. At C
You cannot play D. Therefore, when using both a CD and a DVD, conventionally, both a CD player and a DVD player had to be prepared, which increased costs and required a large installation space.

Therefore, it is considered that such a problem can be solved to some extent by making it possible to reproduce both the CD and the DVD with one disc player. In order to make both CD and DVD reproducible in this way, a disc player 200 as shown in FIG. 12 is usually considered. The disc player 200 includes a CD reproducing section 20 for reproducing a CD 202 on the main chassis 201.
3 and a DVD reproducing section 20 for reproducing the DVD 204
5 are provided.

Subchassis 206 and 207 are provided in each of the reproducing sections 203 and 205, and they are fixed on the chassis 201. The sub chassis 206 and 207 are
Disk drives 208 and 209 are provided for rotating the CD 202 or the DVD 204. In addition, the sub chassis 206 and 207 have a CD 202 or a DVD.
To read the information recorded on 204, each CD
Optical pickup 210 and DVD optical pickup 21
1 is provided. Each optical pickup 210, 211
In order to irradiate the laser beam onto the track of the CD 202 or the DVD 204, objective lenses 212 and 213 are provided.

Each of the optical pickups 210 and 211 includes a guide rod 21 fixed to the sub chassis 206 and 207.
4, moveable along with the CD202 or D
During reproduction of the VD 204, the objective lenses 212 and 213 move along the radius of the CD 202 or the DVD 204.

Racks 216 and 217 are formed on the left end surfaces of the optical pickups 210 and 211 in the figure.
Then, the pinion 22 fixed to the rotation shafts of the motors 218 and 219 attached to the sub chassis 206 and 207, respectively.
0 and 221 are intermediate gears 222, 223, 224 and 22.
It is meshed with the racks 216 and 217 via the No. 5. During reproduction, the rotation of the motors 218 and 219 controls the rotation of the intermediate gears 222, 223, 224, and 225, and the optical pickups 210 and 211 move along the radius of the CD 202 or the DVD 204.

[0009]

However, the above-mentioned disc player 200 judges whether the disc to be reproduced by the user is the CD 202 or the DVD 204, and further, the disc drive unit 208 having two discs, Since it is necessary to determine which of the two, 209, the operability is deteriorated. Depending on the case, it may happen that the CD 202 is mounted on the disk drive unit 209 for DVD, or conversely, the DVD 204 is mounted on the disk drive unit 208 for CD. In this case, since normal reproduction cannot be performed, there is a possibility that it may be judged as a failure.

Such a problem similarly occurs in the disc player dedicated to the CD 202 and the disc player dedicated to the DVD. For example, even if the DVD 204 is mounted on the disc player dedicated to the CD 202, it cannot be normally played back. That is, is the disc the user wants to use is the CD202 or the DVD20?
Since it is necessary to determine whether the number is 4 and mount it on each disc player, the handling becomes troublesome.

Therefore, the present invention solves the above-mentioned problems and proposes a disc discriminating apparatus capable of discriminating the disc type easily.

[0012]

In order to solve the above problems, in the disc discriminating apparatus of the present invention, the information recorded on the disc is mounted on the disc player which is read by the optical pickup means, and the track of the disc is read. A disc discriminating apparatus for discriminating the type of the disc based on a pitch, the disc constant speed rotating means for rotating the disc at a constant rotation speed, and a pickup constant velocity moving means for moving the optical pickup means at a constant speed. An envelope detecting means for converting the detection signal of the optical pickup means into a direct current; a level comparing means for comparing the output of the envelope detecting means with a reference level to convert into high level and low level pulses; Track pitch detecting means for detecting the track pitch of a disc And it is characterized by comprising a disc type discriminating means for discriminating the type of the disc based on the track pitch detected by the track pitch detection means.

[0013]

In the disk discriminating apparatus of the present invention, the disk is rotated at a constant speed by the disk constant speed rotating means, and the optical pickup means is moved at a constant speed along the radial direction of the disk by the pickup constant speed moving means. Here, by appropriately setting the rotation speed of the disc and the moving speed of the optical pickup means, it is possible to surely detect one or more pits recorded in each track of the disc.

In this way, the detection signal detected by the optical pickup means is converted into "high" and "low" pulses through the envelope detection means and the level comparison means. That is, the track portion is, for example, "high", and in this case, the guard portion is "low". The track pitch detecting means calculates the track pitch by dividing the moving distance of the optical pickup means per unit time by the number of tracks per unit time.

The disc discriminating means discriminates the disc type based on the track pitch. For example, if the track pitch is 1.2 μm, it is determined to be a compact disc, and if the track pitch is 0.6 μm, it is determined to be a digital video disc.

[0016]

EXAMPLE Next, an example in which the disc discriminating apparatus according to the present invention is applied to a disc player will be described.
A detailed description will be given with reference to the drawings. For convenience of explanation,
First, a disc player to which the disc discriminating apparatus of the present invention is applied will be described with reference to FIGS.
The details of the disc discriminating apparatus will be described with reference to FIG.

FIG. 5 shows the structure of a disc player 1 to which the disc discriminating apparatus according to the present invention is applied. The disc player 1 can selectively reproduce a compact disc (hereinafter referred to as a CD) 202 which is a first disc or a digital video disc (hereinafter referred to as a DVD) 204 which is a second disc. is there. The disc player 1 is provided with a rectangular chassis 11 for supporting the entire apparatus. A disc drive motor 12, which is a disc rotating means, is arranged on the upper side of the center of the chassis 11, and a CD 202 or a DV is mounted on a rotation shaft 13 of the disc drive motor 12.
Turntable 14 for mounting and fixing D204
Is attached.

Two laterally long openings 25, 26 are formed at predetermined intervals on the left and right sides of the turntable 14 in the figure at target positions with respect to the vertical center line. Opening 25,
The guide rods 27, 2
8 are arranged. Both sides of the guide rods 27 and 28 are rotatably attached to the chassis 11 by supporting portions 29. The guide rod 27 on the left side of the drawing has a first
CD optical pickup 30 which is the optical pickup means of
One end of is slidably fitted. The CD optical pickup 30 is arranged at the reproduction position of the CD 202.

A holding portion 49 is formed on the upper end surface of the CD optical pickup 30 in the drawing so as to hold the upper edge of the opening 25, thereby restricting the rotational position of the CD optical pickup 30 with respect to the guide rod 27. Are doing As a result, during reproduction of the CD 202, the optical pickup 30 for CD accurately moves along a radius of the CD 202 along a predetermined locus. A rack 31 is provided on the lower end surface of the optical pickup 30 for CD.

The rotation shaft 1 of the chassis 11 is attached to the rack 31.
The first gear 102, which is rotatably attached to 01, is meshed with the first gear 102. The second gear 10 is provided on the upper side of the first gear 102.
3 is integrally molded, and the second gear 103 has a chassis 11
Third gear 1 rotatably mounted on the rotary shaft 104 of
05 is meshed. By rotating the third gear 105, the CD optical pickup 30 can be moved along the radius of the CD 202. That is, the third
The gear 105, the second gear 103, the first gear 102, and the rack 31 constitute a first moving unit that moves the CD optical pickup 30.

On the other guide rod 28, a DVD optical pickup 39 serving as a second optical pickup means.
Is slidably fitted. The DVD optical pickup 39 is placed at a position that is in symmetry with the CD optical pickup 30 with respect to the center of rotation of the turntable 14, and the DVD 20
It is arranged at the playback position of 4.

A sandwiching portion 50 is formed on the upper end surface of the DVD optical pickup 39 in the figure so as to sandwich the upper edge of the opening 26 and regulate the rotational position of the DVD optical pickup 39 with respect to the guide rod 28. There is. With this, DV
When reproducing D204, DVD optical pickup 39
Accurately moves along a predetermined trajectory along the radius of the DVD 204. A rack 40 is formed on the lower end surface of the DVD optical pickup 39.

On the rack 40, the rotating shaft 1 of the chassis 11 is
A fourth gear 107, which is rotatably attached to the gear 06, meshes with the gear. The fifth gear 10 is provided on the upper side of the fourth gear 107.
8 is integrally molded, and the fifth gear 108 has a chassis 11
Sixth gear 1 rotatably mounted on the rotary shaft 109 of
10 is meshed. By rotating the sixth gear 110, the DVD optical pickup 39 is moved to the DVD 20.
It can be moved along a radius of 4. That is,
The sixth gear 109, the fifth gear 108, the fourth gear 107, and the rack 40 constitute second moving means for moving the DVD optical pickup 39.

Track pitch of CD202 and DVD20
Since the ratio of the track pitch of 4 is 2: 1, the moving speed of the CD optical pickup 30 and the DVD optical pickup 39
It is necessary to make the ratio to the moving speed of 2: 1. Therefore, in the present example, the second gear 103 of the first moving means for moving the CD optical pickup 30 and the fourth gear 10 of the second moving means for moving the DVD optical pickup 39.
The ratio of the number of teeth to 8 is set to 1: 2. As a result, the number of rotations of the pickup driving means 115 in the CD reproduction mode and the DVD reproduction mode can be made the same, and the control becomes easy.

Two pickup detection sensors 111 and 112 are arranged above the turntable 14 at a predetermined interval. Left pickup detection sensor 111
Is the objective lens 30A of the optical pickup 30 for CD is C
When it is arranged at a position facing the innermost track of D202, the pusher lever 113 is pressed by the holding portion 49 and turned on. As a result, the objective lens 30A of the CD optical pickup 30 is at the reference position, that is, the CD in this example.
It can be detected that it is arranged on the innermost track 202.

Similarly, the pickup detection sensor 1 on the right side
12 is an objective lens 39 of the DVD optical pickup 39.
When A is located at the reference position, which is the position facing the innermost track of the DVD 204 in this example, the holding portion 50 pushes the push lever 114 to turn it on.

A pickup drive motor 115, which is a pickup drive means, is arranged on the lower side of the center of the chassis 11, and a pinion 117 is attached to its rotation shaft 116. In addition, the rotary shaft 116 has a mounting plate 118.
One end is attached. A rotary shaft 119 is provided at the center of the mounting plate 118, and a connecting gear 120 is rotatably mounted on the rotary shaft 119. Connecting gear 12
0 is meshed with the pinion 117.

When the pickup driving motor 115 rotates, a rotational force acts on the connecting gear 120 via the pinion 117, and the connecting gear 120 rotates. At this time, since the position of the connecting gear 120 is not fixed, the pinion 11
It is urged in the same direction as the rotation direction of the pinion 117 by the rotating force of 7, and turns around the pinion 117. Therefore, when the pickup driving motor 115 rotates counterclockwise, the connecting gear 120 rotates counterclockwise around the pinion 117 while rotating clockwise in the clockwise direction.

At the position meshed with the third gear 105, the turning of the connecting gear 120 is stopped, and thereafter, the rotational force of the pickup driving motor 115 is passed through the pinion 117 and the connecting gear 120 to the third gear. 105 is transmitted. That is, the pinion 117 and the connecting gear 120 form a connecting unit that connects the pickup drive motor 115 and the third gear 105 of the first moving unit.

When the pickup drive motor 115 rotates clockwise, the connecting gear 120 rotates clockwise around the pinion 117 while rotating in the counterclockwise direction. Then, the connecting gear 120 stops turning at the position meshed with the sixth gear 110. After that, the rotational force of the pickup drive motor 115 is transmitted to the sixth gear 110 via the pinion 117 and the coupling gear 120. That is, the pinion 117 and the connecting gear 120 form a connecting unit that connects the pickup drive motor 115 and the sixth gear 110 of the second moving unit.

The plunger 12 is located above the connecting gear 120.
1 is disposed, and a laterally long stopper 12 is provided at the tip of the telescopic rod 122 to regulate the position of the mounting plate 118.
3 is fixed. When the plunger 121 is off,
The telescopic rod 122 is constantly extended by the compression spring 124. When the plunger 121 is turned on, the telescopic rod 122 is retracted against the biasing force of the compression spring 124.

The chassis 11 has a disk drive motor 1
2 and the pickup drive motor 115, and a control unit 48 is attached to control the CD optical pickup 30 and the DVD optical pickup 39. Control unit 4
In 8, the reproduction signal processing and the servo control of the disk drive motor 12 and the pickup drive motor 115 are performed as described later.

In this disc player 1, a CD
When reproducing 202, the CD 202 is placed on the turntable 14 as shown in FIG. 5 and clamped by an appropriate clamping means (not shown). Next, the plunger 121 is turned on, the telescopic rod 122 is retracted, and the stopper 123 is arranged in the raised position.

From this state, when the pickup drive motor 115 is rotated counterclockwise as shown in FIG. 6, the connecting gear 120 rotates in the clockwise direction and the pinion 117 rotates.
Turns counterclockwise and stops turning while meshed with the third gear 105. Next, when the plunger 121 is turned off and the telescopic rod 122 is extended, the stopper 1
23 descends and its left end contacts the right side surface of the mounting plate 118. As a result, the connecting gear 120 becomes the third gear 105.
, The pickup drive motor 1
The state in which the CD optical pickup 30 is driven by 15 is maintained.

In this state, the pickup drive motor 1 is further
When 15 is rotated counterclockwise, the optical pickup 30 for CD slides to the right side in the drawing, and stops in a state where the objective lens 30A is arranged facing the innermost track of the CD 202. At this time, the holding portion 49 of the CD optical pickup 30 is detected by the pickup detection sensor 111,
The pickup drive motor 115 is stopped.

In this state, the disk drive motor 12 is rotated to rotate the CD 202 at a predetermined speed, and as shown in FIG.
Rotate 15 clockwise to pick up the CD optical pickup 3
0 is slid along the guide rod 27 to the left side in the figure. Then, the objective lens 30A of the CD optical pickup 30 moves to the outer peripheral side along the radius of the CD 202, and C
The information recorded in D202 is reproduced.

When the DVD 204 is reproduced, the plunger 121 is turned on and the telescopic rod 122 is retracted to raise the stopper 123, as shown in FIG. Then, when the pickup drive motor 115 is rotated clockwise, the connecting gear 120 rotates clockwise around the pinion 117 while rotating counterclockwise as shown in FIG. When the connecting gear 120 meshes with the sixth gear 110, the turning of the connecting gear 120 stops.

When the plunger 121 is turned off in this state, the telescopic rod 122 is extended and the stopper 123 descends, and the right end portion thereof abuts the left side surface of the mounting plate 118. As a result, the state in which the coupling gear 120 is still in mesh with the sixth gear 110, that is, the state in which the rotational force of the pickup drive motor 115 is transmitted to the DVD optical pickup 39 is maintained. At this time, the holding portion 50 of the DVD optical pickup 39 is detected by the pickup detection sensor 112, and the pickup drive motor 1
15 is stopped.

Next, the DVD 20 is placed on the turntable 14.
After 4 is mounted and fixed, the turntable 14 is rotated to rotate the DVD 204 at a predetermined speed as shown in FIG.
The optical pickup 39 for DVD is slid rightward in the figure along the guide rod 28 by rotating 15 in the counterclockwise direction. The objective lens 39A is now the DVD 204
The information recorded on the DVD 204 is reproduced by moving to the outer peripheral side along the radius of.

Now, reproduction signal processing and servo control of the disc player 1 will be described. FIG.
As shown in, the control unit 48 is connected to the above-mentioned CD optical pickup 30 and DVD optical pickup 39. The three-beam method is used for the tracking servo mechanism of each optical pickup 30, 39.

Semiconductor lasers are used as the lasers 51 and 52 of the CD optical pickup 30 and the DVD optical pickup 39, and the laser light emitted from the semiconductor lasers is supplied by APC (overpower control) circuits 53 and 54.
It is controlled so that the temperature is always constant. One of the lasers 51 and 52 of the optical pickups 30 and 39 is selected by the changeover switch 55, and power is supplied to the selected laser 51 or laser 52.

Each of the optical pickups 30 and 39 is provided with photosensors A1 to F1 and A2 to F2, and the CD 20 is provided by these photosensors A1 to F1 and A2 to F2.
2 or the digital signal recorded on the DVD 204 is picked up. Photosensors A1 to F1 and A2
To detection signals SA1 to SF1 and SA2 output from F2
.About.SF2 are supplied to the changeover switch 58 via the wide band amplifiers 56 and 57, respectively, and one of them is selected and supplied to the servo controller 59 as shown in FIG.

In the servo controller 59, the following signals are formed on the basis of the supplied detection signals SA1 to SF1 or the detection signals SA2 to SF2, and the signals are supplied to the subsequent processing system to perform necessary signal processing. . That is, in the servo controller 59, firstly, the detection signal S
A1 to SD1 or detection signals SA2 to SD2 are combined,
This combined output is used as a digital reproduction signal.
The digital reproduction signal is supplied to the error correction circuit 60, where the error is corrected by an error correction code (CIRC code). The output of the error correction circuit 60 is
The data demodulation circuit 61 decodes the data.

When reproducing the CD 202, the output of the data demodulation circuit 61 is converted into an analog signal by the D / A conversion circuit 62, and this is output via a low pass filter (not shown) and the changeover switch 63 as an audio output terminal. It is output from 64.

When reproducing a V-CD (not shown), the output of the data demodulation circuit 61 is the V-CD decoder 6
5 and is converted into an audio signal and a video signal. The audio signal is a low pass filter and changeover switch 6
3 is output from the audio output terminal 64. The video signal is demodulated into a composite video signal and output from the video output terminal 67 via the changeover switch 66.

When the DVD 204 is reproduced, the output of the data demodulation circuit 61 is supplied to the DVD decoder 68, where it is converted into an audio signal and a video signal. The audio signal is output from the audio output terminal 64 via the low pass filter and the changeover switch 63. The video signal is demodulated into a composite video signal and output from the video output terminal 67 via the changeover switch 66.

When reproducing a CD-G (not shown),
The output of the data demodulation circuit 61 is supplied to the CD-G decoder 69, where it is demodulated into a composite video signal,
The image is output from the video output terminal 67 via the changeover switch 66.

In the servo controller 59, secondly, from the detection signals SA1 to SD1 or the detection signals SA2 to SD2, the focus error signal SG1 = (SA1 + SC1).
-(SB1 + SD1) or focus error signal SG
2 = (SA2 + SC2) − (SB2 + SD2) is formed.

When reproducing the CD 202, the focus error signal SG1 formed here is supplied to the focus coil 72 of the CD optical pickup 30 via the dry-per amplifier 70 and the changeover switch 71. Then, focus servo is performed so that the focus error signal SG1 = 0. Further, when reproducing the DVD 204, the focus error signal SG2 is supplied to the focus coil 73 of the DVD optical pickup 39 via the driver amplifier 70 and the changeover switch 71. Then, focus servo is performed so that the focus error signal SG2 = 0.

In the servo controller 59, thirdly, the tracking error signal SH1 = (SE1-SF) from the detection signals SE1, SF1 or the detection signals SE2, SF2.
1) or tracking error signal SH2 = (SE2-S
F2) is formed. When playing the CD202,
The tracking error signal SH1 is transferred to the changeover switch 96,
Via driver amplifier 74 and changeover switch 75,
The tracking servo loop is formed so that the tracking error signal SH1 = 0 is supplied to the tracking coil 76 of the CD optical pickup 30.

When the DVD 204 is reproduced, the tracking error signal SH2 is transferred to the DV via the changeover switch 96, the driver amplifier 74 and the changeover switch 75.
The tracking servo loop is formed so that the tracking error signal SH2 = 0 is supplied to the tracking coil 77 of the D optical pickup 39.

In the servo controller 59, fourthly, the CD 202 or the DVD 2 mounted on the turntable 14 is placed.
Servo signals SJ1 and SJ2 for controlling the disk drive motor 12 are formed so that the linear velocity 04 is constant. Servo signals SJ1 and SJ2 are changed over by a changeover switch 78.
Also, it is supplied to the disk drive motor 12 via the driver amplifier 79. As a result, the rotation speed of the disk drive motor 12 is controlled, and the CD 202 or DVD 2
04 is rotationally driven at a constant linear velocity.

The changeover switch 78 is provided to switch between the case where the disk drive motor 12 is rotated at a constant linear velocity and the case where the disk drive motor 12 is rotated at a constant number of rotations. That is, when the changeover switch 78 is set to the terminal a side, the servo signal SJ1 or the servo signal SJ2 is supplied to the disk drive motor 12, and the disk drive motor 1
2 is rotated at a constant linear velocity. When the selector switch 78 is switched to the terminal b side, the disk drive motor 12
A constant voltage is supplied to the motor to keep the rotation speed constant. The number of revolutions of the disc drive motor 12 is kept constant when disc discrimination processing is performed as described later.

When reproducing the CD 202, the controller 121 is turned on and the stopper 123 is raised. Next, from the controller 84 to the pickup drive motor 11
A mode setting signal SQ indicating the CD reproduction mode is supplied to 5. As a result, the pickup drive motor 115 rotates counterclockwise, the coupling gear 120 meshes with the third gear 105, and the CD optical pickup 30 is placed at the reference position. Next, the plunger 121 is controlled by the controller 84.
Is turned off and the stopper 123 descends. With this, the connecting gear 120 is held in a state of being meshed with the third gear 105.

Next, the above-mentioned servo signal SJ1 output from the servo controller 59 is supplied to the pickup drive motor 115 via the changeover switch 80 and the driver amplifier 81. As a result, the CD optical pickup 30 is moved at a predetermined speed along the radius of the CD 202, and the CD 202 is reproduced.

When the DVD 204 is reproduced, the controller 121 turns on the plunger 121 and raises the stopper 123. Next, from the controller 84 to DV
A mode setting signal SQ indicating the D reproduction mode is output and supplied to the pickup drive motor 115. Now, the pickup drive motor 115 is rotated clockwise this time, and the connecting gear 120 meshes with the sixth gear 110, so that D
The VD optical pickup 39 is arranged at the reference position. Next, the controller 121 turns off the plunger 121, lowers the stopper 123, and the connecting gear 120 moves to the sixth position.
The gear 110 is held in a meshed state.

Next, the servo signal SJ2 output from the servo controller 59 is transferred to the pickup drive motor 11
5, the DVD optical pickup 39 is supplied to the DVD 2
Moved at a predetermined speed along the radius of 04, DV
D204 is reproduced.

The disc player 1 is provided with a disc discriminating circuit 83 as disc discriminating means in order to discriminate automatically the type of the disc mounted on the turntable 14 as described below. There is. here,
By automatically discriminating the type of disc, a DVD decoder 68 used for audio output and D
A / A converter 62 or V-CD decoder 65 is automatically switched, and a DVD used for video output
Switching between the decoder 68 and the other V-CD decoder 65 or CD-G decoder 69 is automatically performed.

The D / A converter 62 for audio output is used.
And V-CD decoder 65 and V for video output
In order to switch between the CD decoder 65 and the CD-G decoder 69, the header information output from the data demodulation circuit 61 is analyzed by the controller 84, and the changeover switch 6 is output by the changeover signal SP output from the controller 84 according to the result.
This is performed by switching 3, 66.

The disc discriminating circuit 83 includes a CD 202 and a D
This is because the difference in the track pitch of the VD 204 is used. That is, as described above, the track pitch of the CD 202 is 1.2 μm, and the track pitch of the DVD 204 is 0.6 μm.
3 is configured to determine the type of disc by detecting this.

[0061] In the disk discrimination process, it is possible to use any towards CD optical pickup 30 and the DVD optical pickup 39 are determined whether to use previously. Here, C is used for disc discrimination processing.
The case of using the D optical pickup 30 will be described, but the same applies to the case of using the DVD optical pickup 39.

In the case of disc discrimination processing, first, the controller 121 turns on the plunger 121 and the stopper 123 rises. Next, the controller 84 sends a mode setting signal SQ indicating the disc discrimination mode.
Is output, and this is supplied to the pickup drive motor 115. Therefore, the pickup drive motor 11
5 rotates, and the connecting gear 120 turns to the side of the optical pickup used in the disc discrimination processing, in this example, the optical pickup 30 for CD, and meshes with the third gear 105. In this state, the plunger 121 is turned off and the stopper 12
3 is lowered and the connecting gear 120 is held in a state of meshing with the third gear 105.

Next, the controller 84 supplies the changeover switches 78, 80 and 96 with the discrimination / reproduction changeover signal SL to change over the changeover switches 78, 80 and 96 to the terminal b. As a result, a constant voltage is supplied to the disk drive motor 12 and the pickup drive motor 115, and these motors 12 and 115 rotate at a constant rotation speed. That is, the disc mounted on the turntable 14 rotates at a constant rotation speed, and the CD optical pickup 30 moves at a constant speed along the radius of the disc. Also CD
The tracking servo of the optical pickup 30 is stopped.

Further, at this time, the controller 84 outputs the switch switching signal SM, which is supplied to the switching switches 55, 58, 71 and 75 for switching between the CD optical pickup 30 and the DVD optical pickup 39. Here, since the CD optical pickup 30 is used for the disc discriminating process, the changeover switches 55, 5
8, 71 and 75 are switched to the terminal a. As a result, the CD optical pickup 30 operates in the same manner as during reproduction, except for the tracking operation. DV for disc discrimination processing
When the D optical pickup 39 is used, the changeover switches 55, 58, 71 and 75 are changed over to the terminal b.

In the case of the disc discrimination processing, the detection signals SA1 to SF1 output from the optical pickup 30 for CD are used.
Are supplied to the disc discrimination circuit 83. In the disc discrimination circuit 83, the detection signals SA1 to SF1 input as shown in FIG. 1 are combined and amplified by the wide band amplifier 91. The output of the wide band amplifier 91 is converted into a direct current by the envelope detector 92, and then this signal is supplied to the level comparator 93 and compared with the reference level. When the combined output is higher than the reference level, a "high" signal is output, and when the combined output is lower than the reference level, a "low" signal is output. Here, as described later, the "high" signal is 1 for one track of the disc.
Is set to be output.

The output of the level comparator 93 is supplied to the track pitch detector 94. Here, the number of "highs" within a predetermined time is counted, and the pitch of the track is detected based on this. The output of the track pitch detector 94 is supplied to the disc type discriminator 95, and whether the disc currently being played is the CD 202 or the DVD 2
The determination of 04 is made based on the track pitch. That is, if the track pitch is 1.2 μm, it is determined to be the CD 202, and if the track pitch is 0.6 μm, it is determined to be the DVD 204.

Here, a specific example of the disc discriminating process will be described. Now, as shown in FIG. 2, turntable 1
Each track T1, T2, T3 of the disk mounted on the No. 4 disc
Are provided with pits P1, P2, P3, .... The disk rotates at a constant rotation speed, C
Since the D optical pickup 30 moves at a constant speed along the radius of the disc, the beam spot B emitted from the CD optical pickup 30 onto the disc is oblique across the tracks T1, T2, T3 as shown in FIG. Draw a locus of movement X that crosses.

At this time, the beam spot B has pits P1, P2, P3 on the tracks T1, T2, T3 ...
... or a guard part without a pit. By increasing the rotation speed of the disk, the beam spot B can be made to always pass over the pit.
In this example, the pit P1 on the track T1 and the track P2
The case where the beam spot B passes through the upper pits P6, P7, P8 and the pits P13, P14 on the track P3 is shown. In this case, the pits P1, P6, P7, ... Through which the beam spot B has passed are detected by the photosensors A1 to D1 of the CD optical pickup 30, and the detection signals SA1 to SD1 are the wide band amplifiers of the disc discriminating circuit 83. It is input to 91. Then, the wide band amplifier 91 outputs a combined signal as shown in FIG.

The combined signal output from the wide band amplifier 91 is supplied to the envelope detector 92, where a detection signal as shown in FIG. 7B is generated and supplied to the level comparator 93. In the level comparator 93, the input detection signal and the reference level are compared, and as shown in FIG. 7C, a pulse higher than the reference level is “high” and a range lower than the reference level is “low”. Is output. This pulse can be set so that approximately one pulse is output for one track by appropriately setting the moving speed of the CD optical pickup 30 and the rotational speed of the disc.

In FIG. 2, the diameter of the beam spot B is 1
μm, width of pits P1, P2, P3 ... 0.5μ
m, and the length is assumed to be 0.9 μm to 3.6 μm in steps of 0.3 μm. Further, it is assumed that when the beam spot B moves by 1 μm of the diameter, the disc moves by the longest two pits, that is, by 7.2 (= 3.6 × 2) μm. .

On the other hand, during reproduction, the optical pickup 30 for CD uses a constant linear velocity (CLV, Constant Linear Vein).
Loss), the moving speed is about 12μm / sec on the inner circumference side,
Although it is 5 μm / sec on the outer peripheral side and there is a difference of more than double, the moving speed of the CD optical pickup 30 is kept constant when the disc discrimination process is performed. This moving speed is, for example, 8 to 9 μm, taking the average of the inner circumference side and the outer circumference side during reproduction.
It is good to set it to m / sec.

Now, the radius of the track T1 is 24 mm,
When the moving speed of the beam spot B is 8 μm / sec, FIG.
To create such a state, the rotation angle of the disk should be (8 × 7.2 ÷ 1000 × 360) / (2 × 24 × π)
The speed must be extremely low, 0.14 ° / sec.

In practice, it is very difficult to rotate the disc at such a low speed because of the reduction ratio and the like.
The disk is rotated at a certain number of rotations.
When the disc is rotated at a high speed, track displacement occurs due to eccentricity. Therefore, it is desirable to rotate the disc at a slower rotational speed than the rotational speed used during reproduction. Normally, the number of rotations of the disk is about 200 rpm when reproducing on the outer peripheral side, and about 550 when reproducing on the inner peripheral side.
Since the speed is up to 600 rpm, it is preferable to rotate the disk at a rotation speed of 200 rpm or less in the disk determination process.

The respective tracks T1, T2 of the disk are
T3 ... has a guard part without pits P1, P2, P3 ...
The track pitch cannot be accurately detected by a method in which only the optical pickup 30 is moved. Therefore, in the disc discrimination process, the disc must be rotated.

When the disc is rotated at, for example, about 200 rpm, the wide band amplifier 91 of the disc discriminating circuit 83 outputs a composite signal as shown in FIG. 4A, and the envelope detector 92 produces the signal shown in FIG. A detection signal as shown is output. Then, the level comparator 93 outputs a pulse as shown in FIG.

This pulse is a track pitch detector 94.
(FIG. 1). The track pitch detector 94 counts the number of pulses per predetermined time and calculates the track pitch from the count value. That is, here, one pulse is generated for one track, and the CD
Since the moving speed of the optical pickup 30 and therefore the beam spot B is constant, the moving distance of the CD optical pickup 30 within a predetermined time is divided by the number of pulses counted within the predetermined time to obtain tracks T1, T2, T3.
・ ・ The pitch of can be obtained.

It is possible to increase the accuracy of detecting the track pitch by gating the output of the wide band amplifier 91 with a gate pulse synchronized with the rotational speed of the disk. In this case, the rotational speed of the disc is the rotational speed at the time of reproducing the inner circumference side, and the optical pickup 3 for CD is used.
It is better to slow down the feed rate of 0.

The track pitch detected by the track pitch detector 94 (FIG. 1) is supplied to the disc type discriminator 95, where the disc type is discriminated based on the track pitch. That is, the track pitch is 1.2μ
If the track pitch is around 0.6 μm, it is determined that this disc is a CD202, if it is around m.
It is determined to be VD204. A discriminating signal SN corresponding to the result of this judgment is output from the disc type discriminator 95 and supplied to the controller 84 (FIG. 11).

Then, the controller 84 controls the respective parts based on the discrimination signal SN, whereby the reproduction processing as described above is performed. That is, the discrimination signal SN
, Indicates CD, all the selector switches 55 to 96 are switched to the terminal a side, and the reproduction of the CD 202 is performed. When the determination signal SN indicates DVD, the changeover switches 55, 58, 63, 66, 71 and 75 are switched to the terminal b side, and the reproduction processing of the DVD 204 is performed. The controller 84 is provided with a play key 97 as an operation switch, a CD / DVD manual switching key 98 for manually switching between a CD mode and a DVD mode, a stop key 99, and the like.

In the disc player 1, since the CD 202 and the DVD 204 are selectively rotated by the common turntable 14 as described above, the structure can be simplified and the size and cost can be reduced. Also CD
Since the pickup 30 for DVD and the pickup 39 for DVD can be driven by the common pickup drive motor 115, the number of parts can be reduced. Further, the disc discriminating circuit 83 automatically discriminates the disc type, and the respective units are automatically controlled in accordance with the discriminant result, so that the CD 202 or the DVD can be controlled.
Since 204 is played back, it is possible to prevent a user's erroneous operation,
Operability is improved.

In the above embodiment, the CD 202 and D
The case where the present invention is applied to the disc player 1 which selectively reproduces the VD 204 has been described.
It can also be applied to a disc player dedicated to the D202 or DVD204. The present invention can also be applied to the case of discriminating the front and back of a disc. That is, since there is no pit on the back surface of the disc, it is judged that the back surface is the one where the track pitch is indefinite.

[0082]

As described above, the disc discriminating apparatus of the present invention is mounted on the disc player and discriminates the disc type based on the track pitch of the disc. Therefore, according to the present invention, when the present invention is applied to a disc player that selectively reproduces a compact disc and a digital video disc, for example, the user simply puts the disc on the turntable of the disc player and Since the mode is set according to the disc and the disc is played back, it is not necessary for the user to discriminate the disc type one by one and to operate the switch according to the disc type, which improves the operability. Has the effect of.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a disc discriminating circuit 83 to which a disc discriminating apparatus according to the present invention is applied.

FIG. 2 is a diagram showing a movement locus of a beam spot B in the disc discrimination processing.

FIG. 3 is a diagram showing a signal waveform of a disc discrimination process in the state of FIG.

FIG. 4 is a diagram showing a signal waveform in an actual disc discrimination process.

FIG. 5 is a block diagram of a disc player 1 to which a disc discrimination circuit 83 is applied.

FIG. 6 is a diagram showing a reproduction state (1/2) of a CD 202.

FIG. 7 is a diagram showing a reproduction state (2/2) of the CD 202.

FIG. 8 is a diagram showing a reproduction state (1/2) of the DVD 204.

FIG. 9 is a diagram showing a reproduction state (2/2) of the DVD 204.

FIG. 10 is a diagram showing a configuration (1/2) of a control unit 48.

FIG. 11 is a diagram showing a configuration (2/2) of a control unit 48.

FIG. 12: Commonly considered CD 202 and DVD 20
4 is a configuration diagram of a disc player 200 capable of selectively reproducing No. 4 of FIG.

[Explanation of symbols]

 1 Disc Player 11 Chassis 12 Disc Drive Motor 14 Turntable 30 Optical Pickup for CD 39 Optical Pickup for DVD 83 Disc Discrimination Circuit 92 Envelope Detector 93 Level Converter 94 Track Pitch Detector 95 Disc Type Discriminator 115 Pickup Drive Motor 120 Connection Gear 202 CD 204 DVD

Claims (3)

[Claims] 1. A disc discriminating apparatus which is mounted on a disc player for reading information recorded on the disc by an optical pickup means and discriminates the disc type based on the track pitch of the disc. Disk constant speed rotating means for rotating at a constant rotation speed, pickup constant speed moving means for moving the optical pickup means at a constant speed, envelope detecting means for converting a detection signal of the optical pickup means into direct current, and the envelope detecting means. Level comparison means for comparing the output of the means with a high level and low level pulse by comparing with the reference level; track pitch detection means for detecting the track pitch of the disk from the pulse; and track pitch detection means Based on the track pitch A disc discriminating apparatus comprising: disc type discriminating means for discriminating a disc type. 2. The disc discriminating apparatus according to claim 1, wherein the disc player is a player for reproducing a compact disc. 3. The disc discriminating apparatus according to claim 1, wherein the disc player is a player for reproducing a digital video disc.