JP3403575B2 - TOC position detecting device for disk device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc device for reproducing discs of different types, and more particularly to a CD (compact disc) and a DVD (digital video disc).
The outer dimensions are the same, but the TOC (Table of
The present invention relates to a TOC position detecting device in a disc device in which discs having different contents area forming positions are used and the positions of the TOC areas of the both discs can be detected with high accuracy.

[0002]

2. Description of the Related Art FIG.
It is called "CD". 3) is a partial plan view of FIG. The CD has a diameter of 120 mm, the center hole 1 for clamping has an inner diameter of 15 mm, and information such as a music program has a radius of 2 mm.
It is standardized that recording may be performed within a range of 33 mm from 5 mm to 58 mm (hereinafter referred to as "information recording area 2"). A read (lead-in) area called a TOC (Table of Contents) (hereinafter referred to as "TOC area 3") is formed on the inner circumference of the information recording area 2 from a radius of 23 mm to 25 mm from the center.
It is formed within a range of 2 mm of mm.

The information recording area 2 is provided with one track spirally continuing from the inner circumference side to the outer circumference side. Recessed pits are formed on this track, and reproduction is performed by reading this pit information from the inner circumference side to the outer circumference side. Also TOC area 3
In the case of a music CD, the song number, index, time data, etc. are recorded. Therefore, when playing back with a normal CD player, it is necessary to detect the TOC area 3 first, and this detection is performed. After that, the information in the information recording area 2 is read.

Conventionally, as the means for detecting the TOC area 3, there are the following methods, for example. FIG. 4 is a plan view showing the structure of a conventional CD player. The rotary table 7 driven by the spindle motor is provided with a centering protrusion 7a, and the center hole 1 of the CD is fitted in the centering protrusion 7a and clamped by a clamper (not shown). The pickup 4 is guided by a pair of guide shafts 6 and 6 and is movable in the radial direction of the CD (X direction), and is moved in the X direction by a pickup moving means (not shown) using a stepping motor or the like. . The pickup 4 is provided with an objective lens 5 facing the recording surface of the CD, and the detection light (laser light) emitted from the light emitting means provided in the pickup 4 is
The signal recording surface of the CD is irradiated from the objective lens 5. Further, inside the pickup 4, a light receiving means such as a photodiode for detecting the return light reflected from the signal recording surface is provided. With the light output of the light receiving means, the signal recorded in the pit on the signal recording surface can be detected, and the focus error signal and the tracking error signal can also be detected.

Further, a contact type limit switch 8 for detecting that the pickup 4 has reached the innermost peripheral position of the CD is provided, and the detector 9 of the limit switch 8 is pushed by the side portion 4a of the pickup 4. At this point, the movement of the pickup 4 in the inner circumferential direction is stopped. At this stop position, the optical axis of the objective lens 5 is set so as to coincide with or be near the reading start position E of the TOC area 3.

[0006]

At present, as a recording medium for the next generation, for example, a digital video disk (hereinafter, referred to as
It is called "DVD". ) Is under development. DVD
Has a diameter of 120 mm and the center hole has an inner diameter of 15 m.
m and the appearance is the same as the CD. Further, both recording methods are pit-based light modulation methods, and both rotation control methods are CLV (constant linear velocity). Therefore, it is possible to develop an upward compatible reproducing apparatus capable of reproducing both discs. However, the appearance of a DVD is the same as that of a CD, but the TOC area has a radius of 22.6 m from the center.
It is formed within a range of only 1.4 mm from m to 24 mm, and both the reading start position of the TOC and the width dimension of the TOC area in the radial direction are different from the CD. Further, the track pitch, linear velocity, recording format, etc. are also different from those of the CD.

Therefore, the following problems occur when an attempt is made to construct a disk device having upward compatibility of CD and DVD. A CD or a DVD is loaded in the playback device, and the determination is performed by the user's selection operation or automatically. Next, when the information recording area 2 is read, the objective lens mounted on the pickup 4 is used. It is necessary to move the optical axis of 5 to the reading start position of the TOC area 3.

However, since the reading start position of the TOC area is different between the CD and the DVD, as shown in FIG. 4, the stop position at the inner circumference of the pickup 4 is set according to the detection output of one limit switch. If decided, it becomes impossible to match the optical axis of the objective lens with the reading start position of the TOC area of either one of the discs.
Although it is possible to provide two limit switches, the distance from the center of the disc to the reading start position of the TOC area is 23 mm for CD and 22.6 mm for DVD, and the difference is 0.4 mm, which is very close. ing. Therefore, providing two limit switches for detection within this close range makes the structure in a small area in the reproducing apparatus very complicated.

The present invention has been made to solve the above-mentioned conventional problems. Even when a disc having different TOC areas such as a CD and a DVD is loaded, the TOC reading start position can be set with high accuracy. It is an object of the present invention to provide a TOC position detection device in a disc device that can be detected.

Further, according to the present invention, even when an error occurs in the detection output of the position detecting means, the reading start position of the TOC area of the disc on the side where high accuracy is required can be surely detected. An object of the present invention is to provide a TOC position detecting device for such a disk device.

Further, the present invention uses two types of T discs.
T in a disk device that can detect the type of the disk by using the operation of detecting the read start position of the OC area
An object is to provide an OC position detecting device.

[0012]

The present invention is directed to reading a TOC.
The time when two types of discs with different starting positions can be installed
The rotation drive unit and the recording surface of the disc installed in the rotation drive unit
A disc with a pickup that moves along
In the device, The pickup is at the inner circumference of the disc
When moving to, the first and second
Position detection means capable of obtaining a detection output is provided,
The position detecting means is a light transmitting section for transmitting light of a predetermined width, and
Moves together with the light receiving part that receives light and the pickup
And a shielding member that shields light of a predetermined width.
The light receiving state of the light receiving section is switched by passing through one edge.
The first detection output is obtained when
Second detection output when the light receiving state of the light receiving unit is switched
Is set to obtainThe first detection output is obtained
When the pickup is
It matches the TOC reading start position of the disk,The aboveSecond inspection
When the output is obtained, the pickup detector is
Match the TOC reading start position of the disc of the type
It is characterized by.

[0013]

Further, the distance the pickup moves between when the first detection output is obtained from the position detection means and when the second detection output is obtained, and the TO of two types of discs.
If there is an error with the distance between the C reading start positions,
When the TOC reading start position of a disc having a narrow TOC area of the two types of discs is used as a reference, and the detector of the pickup coincides with the TOC reading start position of the reference disc, the position detecting means makes a first detection. So that the output can be obtained, and the position where the detector of the pickup opposes the TOC reading start position of the other type of disc,
It is preferable that the error be generated between the time when the second detection output is obtained from the position detection means.

Further, according to the present invention, the number of tracks of the disk traversed by the detection portion of the pickup is counted within the time between when one detection output is obtained from the position detection means and when the other detection output is obtained. However, it is possible to identify the type of the disk installed in the rotation drive unit based on the count value within the time.

The TOC position detecting device of the present invention is provided with a single position detecting means capable of obtaining two types of detection outputs, such as a photo interrupter, a magnetic detecting device, or a mechanical switch having two contacts. . When the pickup moves to the inner peripheral side of the disc, the position detecting means obtains two kinds of detection outputs according to the position of the pickup. At the time when either one of these two kinds of detection outputs is obtained. By stopping the movement of the pickup, the optical axis of the detection portion of the pickup, that is, the objective lens can be made to coincide with the reading start position of each TOC area of different types of disks.

For example, a photointerrupter is provided as the position detecting means, a light transmitting section gives light of a predetermined width so that the light receiving section can receive this light, and a shield member that moves together with the pickup has the light transmitting section and the light receiving section. Try to move between. When the pickup moves to the inner circumference side, the light is first blocked by the edge of the shielding member to switch the light receiving state of the light receiving section to the shielding side, and when the pickup moves further to the inner circumference side, the other edge of the shielding member The part is out of the light passage region, and the light receiving state of the light receiving part is switched to the light receiving side, so that two types of detection outputs can be obtained. Further, even when the pickup moves in the outer peripheral direction, the light receiving state of the light receiving section is once in the shielded state, and then switched to the light receiving state again. Two types of detection output when the pickup moves to the inner circumference side,
Alternatively, the pickup can be controlled to have two stop positions based on two types of detection outputs when the pickup moves to the outer peripheral side. Therefore, when one detection output is obtained, the pickup is stopped, at this time, for example, the detection unit of the pickup is aligned with the reading start position of the TOC area of the CD, and when the other detection output is obtained, the pickup is stopped. At this time, for example, the T of a DVD
The detection unit of the pickup can be matched with the reading start position of the OC area.

When a photointerrupter is used as the position detecting means, two detections are made due to an error in the width dimension of the shield member, a limit in the processing dimension of the shield member, or an error in the processing circuit of the output from the light receiving section. The time difference to get the output,
An error may occur between when the detector of the pickup matches the TOC reading start position of the CD and when it coincides with the TOC reading start position of the DVD. This is the same when a magnetic detection device or the like is used as the position detection means.

In such a case, the timing at which the detection output is obtained from the position detecting means is set with reference to the reading start position of the disk such as the DVD on the side where the TOC area is narrow and high reading accuracy is required. For example, by adjusting the position of the position detecting means, adjusting the circuit, or the like, one of the detection outputs is surely obtained when the detector of the pickup coincides with the TOC reading start position of the DVD. Then, the above-mentioned error amount is given to the detection side of the TOC reading start position of a disc, such as a CD, which has a wide TOC area and has a sufficient reading accuracy. As a result, the TOC reading start accuracy can be increased in the entire device.

Further, for example, when the pickup moves to the inner peripheral side at a constant speed, the time between the time when one detection output is obtained from the position detection means and the time when the other detection output is obtained is used as a reference. Or if the movement distance of the pickup from when one detection output is obtained to when the other detection output is obtained is based on this movement distance, based on the detection output from the tracking error detection unit of the pickup. By counting the number of traversing tracks when the pickup traverses the TOC area of the disc, the disc type can be detected based on this count value. Based on the recognition of the type of the loaded disc after the type detection, the pickup may be stopped based on any of the detection outputs.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an example of the structure of the disk device of the present invention. Reference numeral 14 shown in the figure is a pickup, and an objective lens 15 is provided at the center thereof. The optical axis of the objective lens 15 is the detection unit of the pickup according to the present invention. An objective lens driving device (not shown) is housed inside the pickup 14, and its outer periphery is covered with a cover 14a.

The pickup 14 is mounted on the pedestal 11, and the through-holes 11a1 and 11b1 formed in the supporting portions 11a and 11b of the pedestal 11 and the U-shaped groove 11c1 formed in the supporting portion 11c form a guide shaft. 16 and 16 are respectively supported by loose insertion. In this state, the pickup 14
It is slidable in the X-axis direction shown. On the pedestal 11,
The bearing member 17 in which the thread groove 17a is threaded is mounted on the bracket 2
The screw shaft 18 is engaged with the screw groove 17a. The screw shaft 18 has a feed gear 18a integrally fixed to one end thereof.
Meshes with the gear group 19a of the tracking motor 19. The rotation of the tracking motor 19 gives a rotational driving force to the screw shaft 18 in the α or β direction.
For example, when the screw shaft 18 is rotated in the α direction, the pickup 14 can be moved in the X axis (+) direction, and when the screw shaft 18 is rotated in the β direction, the pickup 14 can be moved in the X axis (−) direction. In the above description, the signal recording surface of the disc is located at a position facing the objective lens 15, the X-axis (−) direction is the inner circumference side of the disc, and the (+) direction is the outer circumference side of the disc.

A metal piece 20, for example, is fixed to one end of the pickup 14 by means such as screwing.
The metal piece 20 includes the arm portion 2 that projects and extends in the X-axis (-) direction.
0a, and a shield plate 2 as a shield member at its tip.
0b is integrally formed by bending. The shield plate 20b is
As the pickup 14 moves, it moves in the X-axis direction in the drawing. Within the moving area of the shielding plate 20b,
A photodetector element indicated by reference numeral 21 is fixed to a chassis or the like (not shown). The light detecting element 21 is a photo interrupter, and in the present invention, the light detecting element 21 and the shielding plate 20 are used.
The position detection means for detecting the position of the pickup 14 is constituted by b and b.

The photo-detecting element 21 has a U-shaped case, and a portion indicated by reference numeral 21a is a light transmitting portion, and a portion opposite to the portion indicated by reference numeral 21b is a light receiving portion. In the light transmitting section 21a, a slit 21c having a predetermined width dimension is formed in the X-axis direction which is the moving direction of the pickup 14, and in the light transmitting section 21a, a light beam corresponding to the width dimension of this slit 21c is received by the light receiving section. It is given toward 21b. When the pickup 14 moves in the X-axis (-) direction, that is, toward the inner peripheral side of the disc, the shield plate 20b enters between the light-transmitting portion 21a and the light-receiving portion 21b of the photodetecting element 21, and the shield plate 20b.
The light receiving portion 21b is in the non-light receiving state only while the is inserted. Therefore, two types of detection outputs can be obtained from the light receiving unit 21b by passing through the edge portion (a) on the X-axis (−) side and the edge portion (b) on the X-axis (+) side of the shielding plate 20b.

As shown in FIG. 1, the received light detection output from the light receiving section 21b is waveform shaped by the waveform shaping section 32,
The rectangular wave whose waveform has been shaped is provided to the control unit 31. Further, the control unit 31 gives a command to the motor drive unit 33, which controls the driving and stopping of the tracking motor 19. Further, the tracking error signal in the detection output of the pickup 14 is the tracking error detection unit 3
4 and is supplied to the control unit 31.

Next, the TOC in the above disk device
A method of detecting the TOC reading start positions of two types of disks using the position detection device will be described. In this disc device, two types of discs can be loaded into the rotary drive unit having a turntable, and in FIG. 2, CD and DVD are shown as these two types of discs. As described above, the reading (recording) start position Ec of the TOC area 3 of the CD is located at a position with a radius of 23.0 mm from the center of the disc, and the width of the TOC area 3 in the radial direction is 2 mm. Further, the reading (recording) start position Ed of the TOC area 3 of the DVD is located at a position with a radius of 22.6 mm from the disc center, and the width dimension of the TOC area 3 in the radial direction is 1.4 mm.
Is.

2A, 2B, and 2C, the pickup 14 moves in the X-axis (-) direction, and the shield plate 20b is
The state in which the slit 21c of the light transmitting unit 21a of the photodetecting element 21 is shielded is shown in order. FIG. 2D shows the light reception output of the light receiving unit 21b in a waveform-shaped state. In the actual output from the light receiving section 21b, the shielding plate 20b
The amount of received light gradually decreases as the slit 21c is gradually closed by the movement of the shield plate 20b.
Due to this, the amount of received light gradually increases as the slit 21c is opened, so that the photoelectric conversion output from the light receiving unit 21b is accompanied by a change in waveform. By detecting the change in the waveform with a predetermined threshold value by the waveform shaping section 32, the rectangular output shown in FIG. 2D is obtained.
Therefore, in FIG. 2, the slit 21c is formed by the shield plate 20b.
When the opening amount increases from the half-closed state, the output from the photo-detecting element 21 is linearly increased from L (low level) to H (high level) and switched, and the slit 21c becomes half. It is assumed that the output from the photo-detecting element 21 is switched from H to L when the opening amount decreases from the closed state.

In FIG. 2A, the edge portion (a) on the inner peripheral side of the shield plate 20b which moves in the X-axis (-) direction approaches the one end on the outer peripheral side of the slit 21c in front of the light transmitting portion 21a. 2D, the slit 21c is fully open at this time, and the output signal of the light receiving unit 21b is (a) in FIG.
Is H (high level). Pickup 1
FIG. 2B shows a state in which 4 further moves in the inner peripheral direction and the edge portion (a) of the shielding plate 20b shields the half position of the slit 21c in the width direction. At this time, the output signal from the photodetector element 21 is switched from H (high level) to L (low level) as shown in FIG. Further, the pickup 14 moves in the inner peripheral direction of the disc, and as shown in FIG. 2C, the outer peripheral edge (b) of the shielding plate 20b is slightly inner peripheral side from the center of the slit 21c in the width direction. 2D, the output signal from the photodetector 21 is switched from L in the region (b) to H in the region (c) as shown in FIG.

On the contrary, when the shielding plate 20b is moved to the outer peripheral side from the state in which it is located slightly on the inner peripheral side of FIG. 2C, the output from the photo-detecting element 21 comes first, Next is In the present invention, is the first detection output from the position detecting means, and is the second detection output.
In the present invention, when the first detection output is obtained,
When the tracking motor 19 is stopped and the movement of the pickup 14 is stopped by a command from the control unit 31, the objective lens 15
The optical axis (detection unit of the pickup) O of the optical disc coincides with the reading start position Ed of the TOC area of the DVD, and when the pickup 14 is stopped when the second detection output is obtained, the optical axis O is the TOC area of the CD. The width W of the shielding plate 20b and the arm 20a are aligned with the reading start position Ec of
The length L0 and so on are determined.

In the above, the slit width Ws is 0.2 m
m and the width W of the shielding plate 20b is 0.4 mm, the amount of movement of the shielding plate 20b from the time when the first detection output is obtained to the time when the second detection output is obtained (from FIG. 2C). The moving amount up to FIG. 2B) is 0.4 mm. This 0.4 mm dimension is equal to the distance between the read start positions Ec and Ed of the TOC areas of the CD and the DVD. Therefore,
If the width W of the shielding plate 20b is set to 0.4 mm and L0 is set appropriately, if the pickup 14 is stopped when the first detection output is obtained, the optical axis O is the read start position Ed of the TOC area of the DVD. When the pickup 14 is stopped when the second detection output is obtained, the optical axis O comes to coincide with the reading start position Ec of the TOC area of the CD. Therefore, based on the type of the loaded disc, the control unit 31 issues a stop command to the tracking motor 19 when the first detection output is obtained or when the second detection output is obtained. This allows
Whether the CD is loaded or the DVD is loaded, the TOC can be immediately read from the stop position of the pickup 14.

It is practically possible to set the width W of the shield plate 20b to 0.4 mm with high accuracy. For example, the shield plate 20b is formed of an extremely thin plate material or a resin film material, and laser processing is performed. By applying,
The setting of 4 mm is possible. However, when the shielding plate 20b is a relatively thick metal plate, the shielding plate 20b is processed by sheet metal processing.
It is difficult to accurately set the width dimension W of b to 0.4 mm. Therefore, a case where the width W of the shielding plate 20b is set to 1.0 mm which can be set by sheet metal working will be described.

In this case, the shield plate 20b from the time when the first detection output is obtained to the time when the second detection output is obtained.
Is 1.0 mm. On the other hand, T of CD and DVD
Since the difference in distance between the reading start positions in the OC area is 0.4 mm, an error of 0.6 mm is generated between the OC area and the moving distance. In this case, by determining the detection output with reference to the disk on the side where the accuracy of the reading start position of the TOC area is required, the above error can be made to have no influence in the actual disk drive.

As shown in FIG. 2, the radial width of the TOC area of the CD is 2 mm, which is relatively large, whereas the radial width of the TOC area of the CD is 1.
It is 4 mm and has little margin. Therefore, the error is 0.6 m
m is given to the TOC detection of the CD. That is, the first
The positions of the respective members are adjusted so that the optical axis O of the objective lens 15 always coincides with the reading start position Ed of the TOC area of the DVD when the detection output is obtained. In this case, when the second detection output is obtained, the objective lens 1
The optical axis O of 5 is located at a position with a radius of 23.6 mm from the center of the disc, and an error is given to the CD detection side.
However, at this time, the TOC of the CD is picked up by the pickup 14.
It is possible to read the remaining area of 1.4 mm, and since information is repeatedly recorded in this TOC area toward the outer peripheral side of the disk, it does not affect the actual data processing.

Even if the width W of the shield plate 20b is set to 0.4 mm with high accuracy, the CD and the DVD may be different from each other due to the tolerance of other parts, the accuracy error of the photo interrupter, or the error in the circuit. The distance of the TOC reading start position,
An error may occur between the detection output and the position where the detection output is obtained. Also in this case, the detection output may be determined with reference to the reading start position of the TOC area of a disk such as a DVD having a short width of the TOC area.

Further, in the above configuration example, the detected output can be used for disc type determination. Figure 2
When the position detecting means shown in FIG. 2 is used, the pickup 14 from when the detection output is obtained to when the detection output is obtained
The moving speed of is constant. That is, when the pickup 14 moves to the inner peripheral side, the controller 31 determines the distance from the time point of FIG. 2B (time point when output is obtained) to the time point of FIG. 2C (time point when output is obtained). Can be recognized at. Therefore, the pickup 14 is moved to the inner peripheral side at a constant speed while applying light from the objective lens 15 to the recording surface of the disc, and from the time when the output is obtained in FIG.
Until the output is obtained in FIG. 2C, the number of track crossings obtained by the tracking error detection unit 34 is counted to identify two types of discs having different track densities, for example, CD and DVD. be able to. After this identification is performed, the control unit 31 can determine whether the tracking motor 19 should be stopped at the time of the output of or the tracking motor 19 should be stopped at the time of the output of. In the above configuration example, the shield plate 20b may be integrally provided with the cover 14a of the pickup 14 or the bracket 22 for mounting the bearing member 17 by extending the same.
In this case, the number of parts can be further reduced.

[0036]

According to the present invention described in detail above, it is possible to accurately detect the reading start position of the TOC position of different types of disks. Further, since only one position detecting means is required, the number of parts can be reduced and the complicated structure in a narrow area in the reproducing device can be simplified.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration example of a TOC position detection device for a disk device according to the present invention,

2A, 2B, and 2C are side views showing the positional relationship between the shielding member and the detection element when the pickup is moved to the inner peripheral side, and FIG. 2D is the detection output accompanying the movement. Diagram showing changes in

FIG. 3 is a plan view showing a recording surface of a CD,

FIG. 4 is a plan view showing the structure of a conventional CD player,

[Explanation of symbols]

2 Information recording area 3 TOC area 14 Pickup 15 Objective lens 20b Shield plate (shield member) 21 Photodetector 21a Light transmitter 21b Light receiving part 21c slit CD compact disc DVD digital video disc Ec CD TOC reading start position Ed DVD TOC reading start position W Shield plate width

─────────────────────────────────────────────────── ─── Continued Front Page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G11B ^7/ 08-7/085 G11B 19/00-19/18 G11B 21/08 G11B 27/34

Claims (3)

(57) [Claims] 1. Two kinds of TOC reading start positions are different.
A rotary drive unit that can install discs of the same kind, and
A picker that moves along the recording surface of the installed disc.
In the disk device provided with When the pickup moves to the inner circumference of the disc
To obtain the first and second detection outputs according to the moving position
Is provided with a position detection means capable ofThe position detecting means is a light transmitting section for transmitting light of a predetermined width, and
Moves together with the light receiving part that receives light and the pickup
And a shielding member that shields light of a predetermined width.
The light receiving state of the light receiving section is switched by passing through one edge.
When the first detection output is obtained, the other edge passes
When the light receiving state of the light receiving section is switched by the
It is set to obtain the detection output, The above When the first detection output is obtained, the pickup
TOC reading start position for one type of disc
MatchesThe abovePick when the second detection output is obtained
-Up detector reads TOC of the other type of disc
For disk devices characterized by matching the start position
TOC position detection device. 2. The distance that the pickup moves between the time when the first detection output is obtained from the position detection means and the time when the second detection output is obtained, and the TOC reading start position of the two types of disks. If there is an error with the distance between the two, the TOC of the disc with the narrow TOC area of the two types of discs
The first detection output is obtained from the position detecting means when the detection unit of the pickup coincides with the TOC reading start position of the reference disk, with the reading start position as a reference, and the TOC of the other type of disk is obtained. Between the position where the detection unit of the pickup faces the reading start position and the time when the second detection output is obtained from the position detection means,
TOC position detection device in the disk drive according to claim 1 Symbol placement was set to the error. 3. The number of disc tracks traversed by the detection unit of the pickup is counted within the time between when one detection output is obtained from the position detection means and when the other detection output is obtained, The TOC position detecting device in the disk device according to claim 1 or 2, wherein the type of the disk installed in the rotation drive unit is identified based on the counted value within the time.