JPH0594629A - Optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To enable an accurate seek and tracking control by controlling a ratio of currents to flow into 1st and 2nd seek coils in accordance with positions of a carriage part and focus adjustment movable part in the radial direction. CONSTITUTION:A relationship between a radially directional position of an optical recording medium and magnetic fields generated by conducting the coils is measured and a relationship between radially directional positions of the seek coils 41 and 42 to be electrified and a current ratio are stored in advance in a current ratio setting table ROM 83. Then, address information detected by an address detecting circuit 84 from a signal to be outputted from a disk reproducing circuit 85 is inputted to a microcomputer 80, where current amts. to flow into the coils 41 and 42 are instructed to current drivers 81 and 82 respectively with reference to the ROM 83. By this method, even when magnetic fields working the coils 41 and 42 respectively are uneven, a ratio of driving force for working the focus adjustment movable part (p) to driving force for working the carriage part (s) is conformed with a mass ratio of (p) to (s) so that resonance can be prevented, and the accurate control can thus be carried out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording / reproducing apparatus for recording / reproducing information or recording / reproducing / erasing information by using an optical recording medium such as an optical disk or a magneto-optical disk, and more particularly, to an accurate recording / reproducing apparatus. The present invention relates to an improvement of an optical recording / reproducing device capable of performing various tracking controls.

[0002]

2. Description of the Related Art Conventionally, as an optical recording / reproducing apparatus of this type, a semiconductor laser (a) as a light source and a diffused laser beam from this semiconductor laser (a) are shown as shown in the schematic diagram of FIG. Collimator lens (b) for converting the laser light into parallel laser light, a beam shaping prism (c) for converting the spot shape of the laser light from an elliptical shape to a substantially circular shape, and an incident laser light incident on the optical recording medium (d). And a beam splitter (e) for separating the reflected laser light reflected from the optical recording medium (d) and a laser light that is linearly polarized light and passes through the beam splitter (e) to be circularly polarized light 1
/ 4 wavelength plate (f), an objective lens (g) that is movably provided and that converges the laser light that has passed through the ¼ wavelength plate (f) onto the convergence surface of the optical recording medium (d), and the beam A cylindrical lens (j) which is incident on a four-division PIN photodiode (h) for obtaining a tracking error signal, a focus error signal, and a reproduction RF signal from the reflected laser light separated by the splitter (e) and its main part The constituent devices are known.

In this optical recording / reproducing apparatus, in order to deal with the eccentricity of the optical recording medium (d) and the waviness and warpage of the surface, the four-division PIN photodiode (h) is used. It is necessary to perform tracking control and focus control of the optical head based on the tracking error signal and the focus error signal, or to perform seek control for moving the optical head from one track to another track for reading recorded information. For example, a drive system as described in Japanese Patent Laid-Open No. 63-50927 is incorporated.

That is, in this drive system, as shown in FIGS. 7 and 8, a yoke (k) is inserted in the cylindrical portion and a focus coil (fc) and a seek coil (sc) are provided on the outer peripheral surface.
And a focus adjustment movable part (p) including a bobbin (m) wound with and an objective lens (g) attached to the bobbin (m) via a holding member (n), and the focus adjustment movable part. A carriage part (s) provided on the rail (q) on which the part (p) is mounted and arranged along the radial direction of the optical recording medium (d) via a bearing (r).
With one end fixed to the focus adjustment movable part (p) and the other end fixed to the carriage part (s), the focus adjustment movable part (p) can be moved in a direction substantially perpendicular to the optical recording medium (d) surface. The leaf spring (t) to be supported constitutes a main part of the leaf spring, and the electromagnetic force acting on the seek coil (sc) upon energization of the seek coil (sc), that is, the seek driving force, is applied to the leaf spring. The focus coil is transmitted to the carriage section (s) through (t), and the carriage section (s) is moved along the radial direction of the optical recording medium (d) to perform seek control and tracking control. With the energization of (fc), this focus coil (fc)
The focus control is performed by moving the focus adjustment movable part (p) in a direction substantially perpendicular to the surface of the optical recording medium (d) by an electromagnetic force acting on the optical disk, that is, a focus driving force.

In the figure, (u) is the seek coil (s).
c) is a permanent magnet that forms a magnetic force line toward the focus coil (fc) side. 9 is a mechanical equivalent diagram of the drive system in the optical recording / reproducing apparatus shown in FIGS. 7 and 8, where (fs) is the seek drive force acting on the focus adjustment movable part (p). Further, (ff) indicates the focus driving force acting on the focus adjustment movable portion (p).

By the way, as described above, the drive system in the conventional optical recording / reproducing apparatus applies the electromagnetic force acting on the seek coil (sc) of the focus adjusting movable portion (p) to the carriage via the leaf spring (t). To the position (s) and integrally move the focus adjustment movable part (p) and the carriage part (s) along the radial direction of the optical recording medium (d) to perform seek control and tracking control. Therefore, when the frequency of the current passed through the seek coil (sc) is set higher than a certain frequency value, that is, the focus adjustment movable part (p) and the carriage part (s) are finely vibrated to perform tracking control. In this case, the electromagnetic force acting on the seek coil (sc) via the leaf spring (t) may not be transmitted to the carriage section (s).

For this reason, there is a drawback that the focus adjustment movable part (p) and the carriage part (s) do not move integrally and a relative displacement occurs, and resonance occurs and the tracking control cannot be performed accurately. It was

Incidentally, FIGS. 10 to 11 show a certain frequency value (equation 1).
FIG. 10 is a graph showing that resonance occurs in the range from 0 to several KHz), and FIG. 10 shows the focus adjustment movable part (p) when the focus adjustment movable part (p) and the carriage part (s) are vibrating. FIG. 11 is a graph showing the relationship between the amplitude and frequency in the focus direction, and FIG. 11 shows the phase of the focus adjustment movable part (p) when the focus adjustment movable part (p) and the carriage part (s) vibrate and the above. It is a graph which showed the relationship with a frequency.

Therefore, in order to eliminate such drawbacks,
As shown in FIGS. 12 to 13, the first seek coil (s) is attached to the focus adjustment movable part (p) and the carriage part (s).
An optical recording / reproducing apparatus has been proposed which incorporates 1) and the second seek coil (s2), respectively.

That is, in this optical recording / reproducing apparatus, as shown in FIGS. 12 to 13, the first seek coil (s) is attached to the focus adjustment movable part (p) and the carriage part (s).
1) and the second seek coil (s2) are respectively incorporated, and a common magnetic circuit, that is, the first seek coil (s2)
1) and a common center yoke (y1) penetrating the inside of the second seek coil (s2), a permanent magnet (m) facing it, a back yoke (y2) and a side yoke (y2) for forming a closed magnetic field. y3).

Then, by the ratio of the common magnetic field and the currents flowing through the first seek coil (s1) and the second seek coil (s2), the drive that acts on the focus adjustment movable part (p) and the carriage part (s). Focus adjustment movable part (p)
And the carriage part (s) are matched with each other in mass ratio to prevent resonance generated by the focus adjusting part (p), the carriage part (s) and the leaf spring (t), and are required for tracking seek, seek control, etc. To obtain the mechanical vibration characteristics.

[0012]

However, the above-mentioned prior art has the following problems. That is, in the above optical recording / reproducing apparatus, as shown in FIG. 14, the magnetic flux generated by the currents flowing through the first seek coil (s1) and the second seek coil (s2) is close to the side yoke (y3). The region passes through the side yoke (y3), whereas the region far from the side yoke (y3) passes through the air gap between the center yoke (y3) and the permanent magnet (m). The magnetic field that should work in common with each of the two seek coils (s2) becomes non-uniform. Therefore, a driving force other than the driving force acting by the magnetic flux originally generated by the permanent magnet (m) is generated by the magnetic flux generated by the currents flowing through the first seek coil (s1) and the second seek coil (s2). However, since the generated magnetic field is non-uniform as described above, the driving force does not match the mass ratio. Therefore, the driving force acting on the focus adjustment movable part (p) and the carriage part (s) is adjusted by the ratio of the currents flowing through the first seek coil (s1) and the second seek coil (s2). And the carriage section (s) cannot be made to match the respective mass ratios, and the resonance generated by the focus adjustment movable section (p), the carriage section (s) and the leaf spring (t) cannot be prevented. There is a problem that it becomes difficult to obtain the required mechanical vibration characteristics.

[0013]

Therefore, the present invention has been made in order to solve the above-mentioned problems of the prior art.
The purpose of this is that even if the common magnetic circuit acting on the first seek coil and the second seek coil is non-uniform along the longitudinal direction, it is applied to each of the first seek coil and the second seek coil. By adjusting the current ratio,
By making the ratio of the driving force acting on the focus adjustment movable part and the carriage part equal to the mass ratio of each of the focus adjustment movable part and the carriage part, the resonance generated by the focus adjustment movable part, the carriage part and the leaf spring can be prevented. Another object of the present invention is to provide an optical recording / reproducing device capable of surely performing accurate seek and tracking control.

That is, the invention described in claim 1 is
An objective lens which is arranged in the vicinity of the optical recording medium and focuses the converged light from the light source on the converging surface of the optical recording medium, and a focus which drives the objective lens in a direction substantially perpendicular to the surface of the optical recording medium by an electromagnetic force accompanying energization. The coil, the first seek coil that drives the objective lens in the radial direction of the optical recording medium surface by the electromagnetic force accompanying energization, and the coil support portion that supports the focus coil and the first seek coil A focus adjustment movable part in which the objective lens, the focus coil, the first seek coil, and the coil supporting part are integrally fixed, and the focus adjustment movable part is mounted and movable in the radial direction of the optical recording medium. And a carriage main body provided on the carriage main body, and the carriage main body is driven in the radial direction of the optical recording medium surface by an electromagnetic force generated by energizing the carriage main body. A carriage part whose main part is constituted by a second seek coil, one end of which is fixed to the focus adjustment movable part and the other end of which is fixed to the carriage part, and the focus adjustment movable part is moved in a direction substantially perpendicular to the optical recording medium surface. An optical system having a leaf spring movably supported, wherein the focus coil of the focus adjustment movable portion and the first seek coil and the magnetic lines of force toward the second seek coil provided in the carriage body are formed by a common magnet. The dynamic recording / reproducing apparatus is provided with a control means for controlling the ratio of the currents flowing through the first seek coil and the second seek coil in accordance with the radial positions of the carriage section and the focus adjustment movable section.

The positions of the carriage section and the focus adjustment movable section in the radial direction may be detected by, for example, the address information included in the information reproduced from the optical recording medium. However, the present invention is not limited to this, and a member that guides the focus adjustment movable unit and the like along the radial direction of the optical recording medium is provided with a unit that detects the radial positions of the carriage unit and the focus adjustment movable unit. The position detecting means may detect the positions of the carriage section and the focus adjustment movable section in the radial direction.

[0016]

According to the first aspect of the present invention, the control means is provided for controlling the ratio of the currents flowing through the first seek coil and the second seek coil according to the radial positions of the carriage section and the focus adjustment movable section. Therefore, even if the common magnetic circuit acting on the first seek coil and the second seek coil is non-uniform along the longitudinal direction, the first seek coil and the second seek coil are made to flow respectively. By adjusting the current ratio, the ratio of the driving force acting on the focus adjustment movable part and the carriage part is made to match the mass ratio of each of the focus adjustment movable part and the carriage part, and the focus adjustment movable part, the carriage part and the leaf spring are adjusted. By preventing the resonance caused by the above, accurate seek and tracking control can be surely performed.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

The optical recording / reproducing apparatus according to this embodiment is
As shown in FIGS. 2 to 3, the focus adjustment movable part (p)
A carriage section (s) carrying the focus adjustment movable section (p), a leaf spring (t) connecting the carriage (s) and the focus adjustment movable section (p), a carriage (s) and a focus. A first seek coil (41) and a second seek coil (4) respectively provided on the adjustable moving part (p).
2) and a magnetic circuit that generates a magnetic field that acts on the first seek coil (41) and the second seek coil (42) constitute a main part thereof.

First, the focus adjustment movable part (p)
Is an objective lens (1), a cylindrical lens holder (2) holding the objective lens (1), and a pair of bobbins (2) fitted and attached to the outer peripheral surface of the lens holder (2). 31) and (31) and the first seek coil (41) (41) wound around the outer peripheral surfaces of these bobbins (31) (31)
And the focus coil (40) (40) pasted on the first seek coil (41) (41) constitute a main part thereof, and these are integrally fixed.

Further, as shown in FIG. 4, a pair of center yokes (5) arranged along the radial direction of the optical recording medium (not shown) in the cylindrical portion of the bobbins (31) (31).
(5) is inserted, and the bobbin (31)
Outside the (31), the first seek coil (41) (41) wound around the outer peripheral surface of these bobbins (31) (31).
And the common permanent magnets (6) and (6) that form magnetic lines of force toward the focus coils (40) and (40) are arranged along the longitudinal direction of the center yokes (5) and (5). (6), the center yokes (5) and (5), the back yokes (9) and (9), and the side yokes (8) and (8) form an endless magnetic circuit.

On the other hand, the carriage part (s) has a carriage body (7) whose upper and lower surfaces are substantially open in the center, and bobbins (32) (32) attached to both front and rear ends of the carriage body (7). And these bobbins (32) (32)
The main portion is composed of the second seek coil (42) and (42) wound around, and the center yokes (5) and (5) are inserted into the cylindrical portions of the bobbins (32) and (32). Has been done.

Bearings (71) (71) are attached to the upper and lower ends of the carriage main body (7) at four positions, respectively, and these bearings (71) (71) are attached.
Are engaged with rails (50) (50) arranged in parallel with the center yokes (5) (5) so that the carriage section (s) moves in the radial direction of the optical recording medium. There is.

The leaf spring (t) is made of a spiral metal material, the inside of which is the lens holder (2) in the focus adjustment movable part (p), and the outside of which is the carriage part (s). It is fixedly attached to the upper and lower open portions of the carriage body (7), and the focus adjustment movable portion (p) can be moved in the vertical direction by the action of the leaf spring (t).

Further, the first seek coil (41) in the focus adjusting section (p) and the second seek coil (42) in the carriage section (s) have a first current driver (81) as shown in FIG. And second current driver (82)
Are connected respectively.

That is, these first current drivers (8
1) and the second current driver (82) are connected in parallel to a microcomputer (80) that outputs signals for controlling tracking and seek operations, and this microcomputer (80) An address information detection circuit (84) for detecting address information of an optical recording medium (not shown) from a signal output from the disk reproduction circuit (84) described in Section 7, tracking error signal and focusing from focused light reflected from the optical recording medium. A disk reproduction circuit (8) for detecting an error signal and an RF reproduction signal
5) and are respectively connected. Further, the microcomputer (80) includes a current ratio setting table RO
M (83) is connected.

In the optical recording / reproducing apparatus having such a configuration, the focused light from the light source (not shown) provided on the apparatus main body side is incident on the objective lens (1) through the reflecting prism (72), The focused light is converged by the objective lens (1) on the converging surface of an optical recording medium (not shown) to record, reproduce, and erase information.

In this optical recording / reproducing apparatus, when the first seek coil (41) and the second seek coil (42) are energized from the first current driver (81) and the second current driver (82), Each bobbin (31) (32)
The electromagnetic force of the permanent magnet (6) acts on the first seek coil (41) and the second seek coil (42) wound around
As shown in the mechanical equivalent diagram of FIG. 5, the first drive force (fs1) acts on the focus adjustment movable part (p), and the second drive force (fs2) acts on the carriage part (s). On the other hand, seek control and tracking control are performed, and when the focus coil (40) is energized, the electromagnetic force of the permanent magnet (6) acts on the focus coil (40), as shown in the mechanical equivalent diagram of FIG. The focus driving force (ff) acts on the focus adjustment movable part (p) to perform focus control.

Here, the first seek coil (41) (4
When the 1) and the second seek coil (42) (42) are energized, a magnetic field is generated by energizing the coil, and the permanent magnet (6)
The driving force generated by the magnetic flux formed by (6) is the first seek coil (41) (41) and the second seek coil (4).
2) Acts on (42).

That is, the first seek coil (41) (4
Two types of forces act on the first seek coil (42) and the second seek coil (42): the original electromagnetic force of the permanent magnets (6) and (6) and the magnetic force of the magnetic field generated by the coil energization. Of these, the electromagnetic force generated by the magnetic field generated by the coil energization passes through the side yoke (8) in the region close to the side yoke (8), whereas the electromagnetic force generated by the coil energization in the region far from the side yoke (8) and the permanent magnet (8). Since it passes through the space between (6), the magnetic fields that should work in common to the first seek coils (41) (41) and the second seek coils (42) (42) become non-uniform, and the focus adjustment movable part (P) or the position of the carriage portion (s) in the radial direction of the optical recording medium.

The relationship between the radial position of the optical recording medium and the electromagnetic force due to the magnetic field generated by the coil energization is obtained by measuring the magnetic field at the radial position of the optical recording medium, and the result is calculated as follows. One seek coil (4
1) The relationship between the current position and the radial position at which the (41) and the second seek coil (42) (42) are energized is written in the current ratio setting table ROM (83) in advance.

Therefore, the address information detected by the address information detection circuit (84) from the signal output from the disk reproduction circuit (84) is input to the microcomputer (80) as shown in FIG. (80) is a current ratio setting table ROM (83)
With reference to the first current driver (81) and the second current driver (82), the first seek coil (41) (41)
And the amount of current flowing through the second seek coil (42) (42), respectively.

As a result, the first seek coil (41) (41) and the second seek coil (42) driven by the first current driver (81) and the second current driver (82).
A current flows in (42) in consideration of the electromagnetic force generated by the magnetic field generated by energization of the coil, and the first seek coil (41) (41) and the second seek coil (42) (4).
2) Even if the magnetic fields acting on each are non-uniform, a driving force corresponding to the mass ratio of the focus adjustment movable part (p) and the carriage part (s) is generated regardless of the radial position of the optical recording medium. (P) and the carriage section (s). Therefore, the ratio of the driving force acting on the focus adjustment movable part (p) and the carriage part (s) can be matched to the mass ratio of each of the focus adjustment movable part (p) and the carriage part (s). By preventing the resonance generated by the movable part (p), the carriage part (s), and the leaf spring (t), good mechanical vibration characteristics can be obtained, so that accurate seek and tracking control can be surely performed. Is possible.

[0033]

The present invention has the above-described structure and operation, and even when the common magnetic circuit acting on the first seek coil and the second seek coil is nonuniform along the longitudinal direction, By adjusting the ratio of the currents flowing through the first seek coil and the second seek coil, the ratio of the driving force acting on the focus adjustment movable part and the carriage part matches the mass ratio of the focus adjustment movable part and the carriage part. Let
By preventing the resonance generated by the focus adjustment movable portion, the carriage portion, and the leaf spring, it is possible to provide an optical recording / reproducing apparatus capable of surely performing accurate seek and tracking control.

[Brief description of drawings]

FIG. 1 is a block diagram of a control circuit showing an embodiment of an optical recording / reproducing apparatus according to the present invention.

FIG. 2 is a partially cutaway perspective view showing a drive system of the embodiment.

FIG. 3 is a partially cutaway front view showing a drive system of the embodiment.

FIG. 4 is a perspective view showing a coil of a drive system of the embodiment.

FIG. 5 is an explanatory view showing a mechanically equivalent device of the drive system of the embodiment.

FIG. 6 is a perspective view showing an optical system of the optical recording / reproducing apparatus.

FIG. 7 is a plan view showing a conventional optical recording / reproducing apparatus.

8 is a sectional view taken along the line 〓-〓 of FIG. 7.

FIG. 9 is an explanatory view showing a mechanically equivalent device of a drive system of a conventional device.

FIG. 10 is a graph showing mechanical characteristics of a drive system of a conventional device.

FIG. 11 is a graph showing mechanical characteristics of a drive system of a conventional device.

FIG. 12 is a partially cutaway perspective view showing another conventional optical recording / reproducing apparatus.

FIG. 13 is a partially cutaway front view showing another conventional optical recording / reproducing apparatus.

FIG. 14 is an explanatory diagram showing a magnetic circuit of a conventional optical recording / reproducing apparatus.

[Explanation of symbols]

p ... Focus adjusting movable part, s ... Carriage, t ... Leaf spring, 41 ... First seek coil, 42 ... Second seek coil, 80 ... Microcomputer (control means)

Claims (1)

[Claims] 1. An objective lens which is arranged in the vicinity of an optical recording medium and focuses converged light from a light source on a converging surface of the optical recording medium, and an electromagnetic force generated when the objective lens is energized to make the surface of the optical recording medium substantially vertical. A focus coil that drives in the direction, a first seek coil that drives the objective lens in the radial direction of the optical recording medium surface by an electromagnetic force accompanying energization, and a coil support portion that supports the focus coil and the first seek coil. And a focus adjustment movable part in which the objective lens, focus coil, first seek coil, and coil support part are integrally fixed, and an optical recording medium equipped with the focus adjustment movable part. The carriage body, which is provided so as to be movable in the radial direction, and the carriage body, which is attached to the carriage body by the electromagnetic force associated with energization A carriage part whose main part is composed of a second seek coil that is driven in a direction, one end of which is fixed to the focus adjustment movable part, and the other end of which is fixed to the carriage part. A leaf spring that supports the movable state in the vertical direction is provided, and the focus coil of the focus adjustment movable portion, the first seek coil, and the magnetic force line toward the second seek coil provided in the carriage body are formed by a common magnet. In the formed optical recording / reproducing apparatus, a control means for controlling the ratio of the currents flowing through the first seek coil and the second seek coil according to the radial positions of the carriage section and the focus adjustment movable section is provided. Characteristic optical recording / reproducing device.