JPH06119640A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain a device by which a smooth linear movement is carried out even if a fitting looseness is caused between the bearing part and a tracking lever in an optical information recording and reproducing device in which the movement of an optical pickup body is carried out by means of a linear motor. CONSTITUTION:In the optical information recording and reproducing device, a leakage magnetic flux 55 is generated from a magnet 50b for driving the linear motor and a yoke 51, a magnetic attraction is generated between the bearing part 53 and the tracking lever 52, and the fitting looseness is absorbed. In addition, by the movement of a speed detection coil 54 through the leakage magnetic flux 55, an electromagnetic speed output is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording / reproducing apparatus for driving an optical reproducing apparatus body.

[0002]

2. Description of the Related Art FIGS. 3 to 11 show a conventional optical information recording / reproducing apparatus, and FIG. 3 schematically shows a structure of an optical recording / reproducing apparatus main body (hereinafter referred to as an optical pickup main body). FIG. 4, FIG. 4 is an explanatory view of a structure in which a light beam is irradiated onto a disc, FIG. 5 is an explanatory view showing a waveform obtained by converting reflected light from the disc into an electric signal, and FIG. 6 is a bottom view of the entire conventional device. 6 is a plan view from the direction of arrow C in FIG. 6, FIG. 8 is a side view from the direction of arrow D in FIG. 6, FIG. 9 is an enlarged view of the speed detecting portion of the moving body 20, and FIG. FIG. 11A is a circuit block diagram for driving the optical pickup main body of the conventional device, FIG. 11A is a characteristic diagram of speed sensor signal vs. speed output from the speed signal detector of FIG.
FIG. 11B is a characteristic diagram of the tracking signal output from the tracking signal detector of FIG. 10 versus time.

In FIGS. 3 to 5, reference numeral 15 is an optical pickup body, and a light beam 5 emitted from a light source 1 is focused on a disk 7 through a diffraction grating 2, a half mirror 3, a collimating lens 4 and an objective lens 6. And then illuminated, Figure 4
, The light spots 18a, 1 on the disk 7
8b and 18c are formed. On the other hand, on the disk 7, information pits 9 representing information communication contents, for example, in length, are concentric,
Alternatively, the information tracks are formed by being sequentially arranged in a spiral shape. The disk 7 is rotatably held by a turntable 16 and a pressing means 17 provided on the motor 8.

Reflected light 13 from the disk 7 travels backward in the incident path, passes through the half mirror 3, and passes through the sensor lens 11.
Then, the light is incident on the photodetector 12 and is converted into an electric signal by the photodetector 12. Then, by processing the output signal of the photodetector 12, the information recorded on the disk 7 can be reproduced. Further, based on the output signal of the photodetector 12, the light spots 18a, 18b on the disk 7,
The shift signals of the focus direction (arrows A and A'directions) and the track direction (arrows B and B'directions) of 18c can be taken out.

FIG. 5 shows a tracking signal output showing an example of the converted electric signal. When the disk 7 rotates, vertical vibrations in the directions of arrows A and A'and eccentric movements in the directions of arrows B and B'are generated. Therefore, the focus drive device 6b moves the objective lens 6 in the directions of the arrows A and A'to focus on the vertical vibration by the focus shift signal obtained from the output signal of the photodetector 12, and also performs the decentering operation. On the other hand, the track driving device 6a corrects the deviation from the track position by moving the objective lens 6 in the arrow directions B and B'according to the track deviation signal (FIG. 5). Reference numeral 14 denotes an actuator section on which the focus drive device 6b and the track drive device 6a are mounted.

In FIGS. 6 to 9, reference numeral 20 denotes a movable body 20a on which an optical pickup main body 15 is mounted and which controls linear movement.
Reference numeral 20b is a bearing portion provided on the moving body 20 and has a through hole. Reference numerals 21a and 21b are rail rods penetrating the bearing portions 20a and 20b, respectively.
The moving body 20 slides with 1b as a guide.

Reference numerals 22a, 22b, 23a and 23b are holders for indicating the rail rods 21a and 21b, and 24 is a drive coil, which is fixed to the moving body 20. Reference numeral 25 is a yoke, and the drive coil 24 is installed so as to penetrate a part of the yoke 25.

Reference numerals 26a and 26b are single pole magnetized magnets, which are fixed to the yoke 25. Reference numeral 27 is a speed detection coil, which is fixed to the moving body 20. 28
Is a yoke, and the speed detection coil 27 penetrates a part of the yoke 28. Reference numeral 29 denotes a plate thickness direction unipolar magnetized magnet, which is fixed to the yoke 28. Three
Reference numeral 0 is a base for fixing the holders 22a, 22b, 23a, 23b and the yokes 25, 28.

In FIG. 10, reference numeral 31 is a tracking signal detector, which converts the signal from the photodetector 12 into a tracking signal. Reference numeral 32 denotes a tracking control device, which processes a signal from the tracking signal detector 31 and operates the lens driving device 6a via a tracking actuator driving circuit 33, and also operates a position error amplifier 34 and a changeover switch 39 described later. And the drive coil 24 is excited via the linear motor drive circuit 35.

A velocity signal detector 36 detects the signal from the velocity detecting coil 27. Reference numeral 37 is a linear motor control device, which processes signals from the speed signal detector 36 and the tracking control device 32, and drives the drive coil 24 via a speed error amplifier 38, a changeover switch 39 described later, and a linear motor drive circuit 35. Get excited. 39
Is a switch for switching the output from the position error amplifier 34 and the speed error amplifier 38.

Next, the operation of the conventional device will be described.
In FIG. 3, the reflected light 13 is incident on the photodetector 12, where it is converted into an electric signal. And this photodetector 12
The information recorded on the disc 7 is reproduced by electrically processing the output signal from the disc 7
The focus position shift signal of the upper light spots 18a, 18b, 18c and the shift signal from the track are extracted. Figure 10
The output from the tracking signal detector 31 in is the track shift signal, and has the waveforms shown in FIGS. 5 and 11B.

In the above operation, the focus driving device 6b and the track driving device 6a vertically vibrate in the directions of arrows A and A'which are perpendicular to the disk 7 when the disk 7 rotates and the arrows B and B'parallel to the disk 7. For the eccentricity in the direction, the deviation is corrected. Then, the tracking signal detector 31, the tracking control device 32 shown in FIG.
The tracking actuator drive circuit 33 controls the operation of the condenser lens 6 in the directions of arrows B and B '.

When reproducing the entire area of the information on the disk 7, the moving body 20 equipped with the optical pickup body 15 is mounted.
Is linearly moved on the rail rods 21a and 21b in FIGS. 6, 7 and 8 in the directions of arrows L and L'in the figures. The yoke 2 in which the drive coil 24 is fixed to the moving body 20 and the single-pole magnetized magnets 26a and 26b are fixed to both ends.
Since a part of 5 penetrates the inside of the drive coil 24, when a current is applied to the drive coil 24 from the linear motor drive circuit 35 in FIG. Move in the L and L'directions. In this case, when the applied current is constant, the moving body 20 makes an acceleration motion, and therefore it is necessary to control the speed of the moving body 20 using the speed detecting coil 27.

The speed detecting coil 27 is fixed to the moving body 20, a part of the yoke 28 penetrates the content thereof, and a magnet 29 magnetized in the plate thickness direction to a single pole is fixed to one end of the yoke 28. Therefore, when the moving body 20 moves in the direction of the arrow L ′, the speed detecting coil 27 also moves,
A known electromagnetic induction current outputs a speed sensor signal proportional to the moving speed shown in FIG. 11A, and this speed sensor signal is supplied to speed control.

Usually, a light beam 18 is emitted from a pit 9 on one track on the disk 7 to a pit 9 on another track.
When moving a, 18b, and 18c, the number of tracks from the current pit 9 to the pit 9 on the target track is first calculated using the tracking control device 37 in FIG. The position of the moving body 20 is detected by counting the tracking signal W, and the speed error amplifier 38 and the linear motor drive circuit 3 are detected.
5 is used to move the moving body 20 to the vicinity of the target track.

The linear motor controller 37 detects the speed sensor signal V from the speed signal detector 36, and controls the speed of the moving body 20 within a range in which the tracking signal W can be counted. After the moving body 20 has moved to the vicinity of the target track, the changeover switch 3
9 is switched, the tracking control device 32 uses the tracking signal W to finely move the moving body 20 via the position error amplifier 34 and the linear motor drive circuit 35, and the tracking drive device 6a via the tracking actuator drive circuit 33. Move slightly. This mobile 2
The light beams 18a, 18b, and 18c are positioned on the target pit 9 by minute movement of the track drive device 6a and 0.

[0017]

Since the conventional optical information recording / reproducing apparatus is constructed as described above, the moving body 2 is moved when the light beam moves from the pit 9 to another pit 9.
The bearing portion 20a and the rail rod 21a that serve as a reference for the positioning of 0.
If an initial fitting gap between the moving body 20 and the fitting gap due to wear of the bearing portion 20a occurs, rattling occurs in the linear sliding of the moving body 20 in the directions of the arrows L and L ', and the light beam 18
It becomes difficult to position a, 18b, and 18c in the pit 9 on the target track on the disk 7, and in some cases, the amount of movement of the speed detection coil 27 becomes larger than the amount of movement of the drive coil 24 due to rattling, so that accurate speed There was a problem that it could not be detected.

The present invention has been made to solve the above problems, and it is an initial fitting gap between a bearing and a rail that serves as a reference for positioning a moving body and a fitting gap due to wear of the bearing. It is an object of the present invention to obtain an optical information recording / reproducing apparatus capable of ensuring accurate linear sliding of a moving body even if the above occurs.
Another object of the present invention is to obtain an optical information recording / reproducing device in which the rail rod can be used as a speed detecting means.

[0019]

In the optical information recording / reproducing apparatus according to the present invention, a linear motion of a moving body is positioned, a bearing portion made of a magnetic material is provided on the moving body, and the bearing portion is allowed to pass therethrough. By providing a rail rod composed of the above in the fixed portion, a positioning means for positioning the moving body is constituted, and the positioning means is magnetized by the leakage magnetic flux from the magnetic circuit composed of the magnet and the yoke, and the rail rod and the bearing portion. Is magnetically adsorbed.

Further, a speed detecting coil fixed to the bearing portion of the positioning means and penetrating a rail rod is provided, and the speed detecting coil moves in the leakage magnetic flux to detect the speed information of the moving body. It is a thing.

[0021]

The optical information recording / reproducing apparatus according to the present invention is
Even if the bearing part and the rail rod magnetized by the leakage magnetic force from the magnet and the yoke are magnetically attracted and the initial fitting between the bearing part and the rail rod and the fitting gap due to the bearing wear occur, the moving body is moved by the magnetic preload. Smoothly slides straight.

Further, the velocity detection coil, which is fixed to the bearing portion and positioned so that the rail rod passes through, moves in the leakage magnetic flux between the magnet, the yoke and the rail rod. Detect the electromotive voltage.

[0023]

【Example】

Example 1. 1 is a plan view of the entire optical information recording / reproducing apparatus showing an embodiment of the present invention, and FIG. 2 is an arrow M in FIG.
It is a partial cross-sectional enlarged view of the drive coil periphery seen from the direction.
In the figure, the same or corresponding parts as those of the conventional example are designated by the same reference numerals, and the description thereof will be omitted.

50a and 50b are magnets for driving a linear motor, and 51 is a yoke. In the magnetic circuit composed of the magnet 50b and the yoke 51, a leakage magnetic flux 55
Occurs. 52 is a rail rod formed of a magnetic material;
Is a bearing portion that serves as a reference for positioning the moving body 20, 53a is a magnetic ball bearing formed in the bearing portion 53,
Is a speed detection coil fixed between the bearings 53. Further, R ₁ is the outer diameter of the rail rod 52, and R ₂ is the inner diameter of the bearing 53.

Next, the operation will be described. Here, the operation of each part in the optical pickup main body 15 and the normal movement operation control means on the rail rods 21b and 52 of the optical pickup main body 15 and the moving body 20 are the same as those in the conventional example, and therefore the description thereof is omitted. 1, in FIG. 2, due to the initial fitting gap between the rail rod 52 and the bearing portion 53 and wear of the bearing portion 53, R ₂ −
Moving body 20 when the fitting gap calculated by R ₁ occurs
The operation of the linear sliding will be described.

In the conventional example, accurate linear sliding of the optical pickup body 15 and the moving body 20 in the directions of the arrows L and L'has been hindered. However, in the present invention, the magnetic force of the magnet 50b and the yoke 5 are set so that the magnetic flux density in the yoke 51 is saturated.
A thickness of 1 is set, and a magnetic circuit is formed by the magnet 50b and the yoke 51. Further, the bearing portion 53 and the rail rod 52, which are made of a magnetic material, are attached to the magnet 50b and the yoke 5
Close to 1. As a result, the leakage magnetic flux 5 from the magnetic circuit
When the rail rod 52 and the ball bearing 53a are magnetized by 5 and a magnetic preload is applied in the direction of arrow X in FIG. As a result, the optical pickup body 15 and the moving body 20 can be accurately linearly slid even if there is some fitting gap.

Example 2. Further, the speed detecting coil 54 fixedly held between the bearing portions 53 and arranged so that the rail rod 52 penetrates the speed detecting coil 54 across the leakage magnetic flux 55 when the optical pickup body 15 and the moving body 20 slide linearly. By flowing the counter electromotive current in the speed detection coil 54, the speed sensor signal shown in FIG. 11A of the conventional example can be obtained. After that, the moving body 20 is controlled by using this speed sensor signal for speed control as in the conventional example.

[0028]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, accurate linear movement is possible even if an initial fitting gap during manufacture or a fitting gap due to bearing wear during long-term use occurs. It is possible to obtain an optical information recording / reproducing device having a moving body, and the speed detection coil makes it unnecessary to install a large-scale magnetic circuit exclusively for speed detection, which simplifies and downsizes the device and is inexpensive. The effect is that a device can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view of the entire optical information recording / reproducing apparatus showing an embodiment of the present invention.

FIG. 2 is a partial enlarged cross-sectional view of an optical information recording / reproducing apparatus showing an embodiment of the present invention.

FIG. 3 is a configuration diagram showing a conventional optical information recording / reproducing apparatus.

FIG. 4 is an explanatory diagram of a configuration in which a conventional light beam is irradiated onto a disc.

FIG. 5 is a waveform explanatory diagram obtained by converting reflected light from a conventional disc into an electric signal.

FIG. 6 is a perspective view of the entire conventional optical information recording / reproducing device as viewed from below.

7 is a plan view from the direction of arrow C in FIG.

FIG. 8 is a side view from the direction of arrow D in FIG.

9 is an enlarged view of a speed detection unit in FIG.

FIG. 10 is a circuit block diagram for driving an optical pickup body of a conventional optical information recording / reproducing apparatus.

11A is a characteristic diagram of a speed sensor signal output from the speed signal detector of FIG. 10 with respect to speed. FIG. FIG. 11B is a characteristic diagram of the tracking signal output from the tracking signal detector of FIG. 10 versus time.

[Explanation of symbols]

 15 Optical pickup main body 20 Moving body 24 Drive coil 50a Linear motor drive magnet 50b Linear motor drive magnet 51 Yoke 52 Rail rod 53 Bearing 54 Speed detection coil 55 Leakage magnetic flux

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[Procedure amendment]

[Submission date] November 24, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

In FIGS. 6 to 9, reference numeral 20 denotes a movable body 20a on which an optical pickup main body 15 is mounted and which controls linear movement.
Reference numeral 20b is a bearing portion provided on the moving body 20 and has a through hole. 21a and 21b are the bearing portions 20a and 20b.
Rail rods penetrating each of these rail rods 21a,
The moving body 20 slides with the guide 21b as a guide.

Claims (2)

[Claims] 1. An optical information recording / reproducing apparatus main body for irradiating an information beam of an optical information recording unit with a light beam and receiving reflected light, and a moving body for mounting the information recording / reproducing apparatus main body to perform linear motion. A base supporting the moving body, a driving coil provided on one of the moving body or the fixed portion, and a yoke and a single-pole magnetized magnet on the other side.
In an optical information recording device including a linear motor driving means for moving the moving body, a linear motion of the moving body is positioned, a bearing portion made of a magnetic material is provided on the moving body, and the bearing portion is passed. By providing a rail rod made of a magnetic body on the fixed portion, a positioning means for positioning the moving body is configured, and the positioning means is magnetized by a leakage magnetic flux from a magnetic circuit composed of the magnet and the yoke. An optical information recording / reproducing device is characterized in that the rail rod and the bearing portion are magnetically attracted. 2. A bearing fixed to the positioning means,
2. An optical information recording / reproducing apparatus according to claim 1, further comprising a speed detecting coil penetrating a rail rod, wherein the speed detecting coil moves in the leakage magnetic flux to detect speed information of the moving body. apparatus.