JPH0622059B2 - Optical recording / reproducing device - Google Patents

Description

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 and a magneto-optical disk. In particular, the present invention relates to an improvement of an optical recording / reproducing device capable of surely performing accurate seek and tracking control.

[Prior Art] As an optical recording / reproducing apparatus of this type, as shown in the schematic configuration diagram of FIG.
A collimator lens (b) for converting the diffused laser light from the semiconductor laser (a) into parallel laser light; and a beam shaping prism (c) for converting the spot shape of the laser light from an elliptical shape to a substantially circular shape. , A beam splitter (e) for separating incident laser light incident on the optical recording medium (d) and reflected laser light reflected from the optical recording medium (d)
And a quarter-wave plate (f) that passes the beam splitter (e) and converts the linearly polarized laser light into circularly polarized light,
An objective lens (g) that is movably provided to converge the laser light that has passed through the quarter-wave plate (f) onto the converging surface of the optical recording medium (d), and reflection that is separated by the beam splitter (e). There is known a device that constitutes a main part of a cylindrical lens (j) that causes a laser beam to enter a four-division PIN photodiode (h) for obtaining a tracking error signal, a focus error signal, and a reproduction RF signal.

Then, 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 tracking error signal obtained by the four-division PIN photodiode (h) is obtained. It is necessary to perform tracking control or focus control of the optical head on the basis of a focus error signal or seek control for moving the optical head from one track to another track for reading recorded information. A drive system as described in JP-A-63-50927 is incorporated.

That is, this drive system, as shown in FIGS.
A bobbin (m) in which a yoke (k) is inserted into the cylindrical portion and a focus coil (fc) and a seek coil (sc) are wound around the outer peripheral surface, and a holding member (n) is interposed on the bobbin (m). A focus adjustable part (p) including an objective lens (g) attached to the optical recording medium and a rail (q) mounted with the focus adjustable movable part (p) along the radial direction of the optical recording medium (d). ) A carriage part (s) movably provided above the bearing (r), one end of the focus adjustment movable part (p), and the other end of the carriage part (s).
The main part is constituted by a leaf spring (t) which is fixed to the above and supports the focus adjustment movable portion (p) so as to be movable in a direction substantially perpendicular to the surface of the optical recording medium (d). With the energization of the coil (sc), this seek coil (s
The electromagnetic force acting on c), that is, the seek driving force is transmitted to the carriage section (s) via the leaf spring (t), and the carriage section (s) is moved in the radial direction of the optical recording medium (d). While performing seek control and tracking control by operating, the focus adjustment movable part (p) is optically driven by the electromagnetic force acting on the focus coil (fc) when the focus coil (fc) is energized, that is, the focus driving force. The focus control is performed by moving the recording medium (d) in a substantially vertical direction.

In the figure, (u) is a permanent magnet that forms magnetic lines of force toward the seek coil (sc) and the focus coil (fc). Further, FIG. 19 is a mechanical equivalent diagram of a drive system in the optical recording / reproducing apparatus shown in FIGS. 17 to 18, and in the figure,
(F _s ) shows the seek drive force acting on the focus adjustment movable part (p), and (f _f ) shows the focus drive force acting on the focus adjustment movable part (p).

By the way, as described above, in the drive system of the conventional optical recording / reproducing apparatus, the electromagnetic force acting on the seek coil (sc) of the focus adjustment movable portion (p) is applied to the carriage portion (s) via the leaf spring (t). ), The focus adjustment movable part (p) and the carriage part (s) are integrally moved along the radial direction of the optical recording medium (d) to perform seek control tracking control. Seek coil (sc)
If the frequency of the current flowing in
That is, when tracking control is performed by finely vibrating the focus adjustment movable part (p) and the carriage part (s), the seek coil (sc) is passed through the leaf spring (t).
The electromagnetic force acting on the carriage may not be transmitted to the carriage section (s).

Therefore, the focus adjustment movable part (p) and the carriage part (s) do not move integrally and a relative displacement occurs, and resonance occurs, so that the tracking control cannot be performed accurately.

20 to 21 show certain frequency values (several 100 to several kHZ)
FIG. 4 is a graph showing that resonance occurs in
FIG. 20 is a graph showing the relationship between the amplitude and frequency in the focus direction of the focus adjustment movable part (p) when the focus adjustment movable part (p) and the carriage part (s) are vibrating, FIG. 21. Is the focus adjustment movable part (p)
6 is a graph showing the relationship between the phase of the focus adjustment movable part (p) and the frequency when the carriage part (s) is vibrating.

Therefore, in order to eliminate such drawbacks, as shown in FIGS. 22 to 23, the first seek coil (s1) and the second seek coil (s1) and the second seek coil (s1) are provided in the focus adjustment movable part (p) and the carriage part (s). Optical recording / reproducing devices have been proposed that incorporate s2).

That is, in this optical recording / reproducing apparatus, as shown in FIG. 24, the first seek driving force (f _s1 ) acts on the focus adjustment movable portion (p), while the second seek portion moves on the carriage portion (s). Since the seek driving force (f _s2 ) directly acts, it is not necessary to transmit the seek driving force to the carriage portion (s) via the leaf spring (t), and thus the seek driving force (s1) is not required. Second seek coil (s2)
The above-mentioned resonance phenomenon can be prevented regardless of the frequency value of the electric current flowing through.

[Problems to be Solved by the Invention] By the way, in this optical recording / reproducing apparatus, as shown in FIGS. 22 to 23, a first coil supporting portion (m1) for supporting the first seek coil (s1) is provided. And the second seek coil (s
Insertion part (m3) of the second coil support part (m2) that supports 2)
The plate-shaped permanent magnets (u) are arranged along the length direction of the center magnetic yoke (kc) inserted in (m4), and the first seek coil (s1) and the second seek coil (s2) are provided. Is adjusted so that a uniform magnetic field is formed toward
Further, the center magnetic yoke (kc), the back magnetic yoke (kb) wired along the length direction of the center magnetic yoke (kc), the center magnetic yoke (kc) and the back magnetic yoke (kc). kb) and a pair of side magnetic yokes (ks) (ks) connecting the center magnetic yoke (kc) and the back magnetic yoke (kb) provided on both ends of the end magnetic yoke (k). The permanent magnet (u) prevents the magnetic field from being dispersed by the endless magnetic yoke (k).
The structure is such that the magnetic field formation rate from the can be increased.

However, in the case of such a structure, the first seek coil (s1) and the second seek coil (s1) are connected to the first seek coil (s1) and the second seek coil (s2) by energization.
The center magnetic yoke (kc) is magnetized by the coil magnetic field generated from the 2) side, and the uniform magnetic field of the permanent magnet (u) is easily disturbed by the magnetizing magnetic field on the yoke side from the magnetized center magnetic yoke (kc) side. Therefore, there is a problem that tracking control and seek control cannot be performed accurately.

That is, the yoke side energizing magnetic field from the side of the center magnetic yoke (kc) forms a magnetic circuit (α) as shown in FIG. 25, and the side magnetic yoke (ks) (k) of this magnetic circuit (α) In the region close to ks), the magnetic field lines pass through the side magnetic yokes (ks) (ks), so the uniform magnetic field of the permanent magnet (u) is less affected, while the side magnetic yokes (ks) ) (Ks), the magnetic field lines pass through the air gap between the center magnetic yoke (kc) and the back magnetic yoke (kb) in the region away from (ks), which has a great effect on the uniform magnetic field of the permanent magnet (u). Therefore, there is a drawback that the uniform magnetic field of the permanent magnet (u) is disturbed in the central region of the center magnetic yoke (kc) and the region on the side magnetic yoke (ks) (ks) side. The direction of the magnetic field of One seek coil (s1)
Since it constantly changes with the reversal of the energization direction of the second seek coil (s2), there is a drawback that the disturbance of the uniform magnetic field of the permanent magnet (u) becomes further large.

Therefore, the electromagnetic force strength acting on the central region of the center magnetic yoke (kc), the side magnetic yoke (ks) (ks) side region, the first seek coil (s1) and the second seek coil (s2) varies. Since it becomes easy, it becomes difficult to obtain the required mechanical vibration characteristics, and there is a problem that seek and tracking control cannot be performed accurately as before.

The lengths of the center magnetic yoke (kc) and the back magnetic yoke (kb) in the endless magnetic yoke (k) are set to be large, and the moving range of the carriage portion (s) is set to the central portion of the center magnetic yoke (kc). A method of preventing the above-mentioned adverse effect by specifying the area can be considered, but when such a method is adopted, the space for disposing the endless magnetic yoke (k) becomes large correspondingly, and it becomes unsuitable for downsizing of the recording apparatus. , Could not be a realistic solution.

[Means for Solving the Problem] The present invention has been made in view of the above problems, and the problem is to provide an optical recording / reproducing apparatus capable of surely performing accurate seek and tracking control. Especially.

That is, the invention according to claim 1 is an objective lens arranged in the vicinity of an optical recording medium for converging the converged light from a light source to a converging surface of the optical recording medium, and an optical force generated by energizing the objective lens. A focus coil for driving in a substantially vertical direction, and a first seek coil for driving the objective lens in a radial direction of an optical recording medium by an electromagnetic force accompanying energization,
A main part of the focus coil and a first coil support part supporting the first seek coil is formed, and these objective lens, focus coil, first seek coil, and first coil support part are integrally formed. A fixed focus adjustment movable part, a carriage main body on which the focus adjustment movable part is mounted and is provided so as to be movable in the radial direction of the optical recording medium, and an electromagnetic field associated with conduction provided on the second coil support part of the carriage main body. A carriage part whose main part is a second seek coil that drives the carriage body in the radial direction of the optical recording medium by force, and one end is fixed to the focus adjustment movable part and the other end is fixed to the carriage part. A leaf spring that supports the movable portion in a state of being movable in a direction substantially perpendicular to the surface of the optical recording medium, and a first coil support of the focus adjustment movable portion. Magnetic yoke inserted through an insertion portion formed in the second coil support portion of the carriage portion and the carriage portion and arranged in the radial direction of the optical recording medium, and arranged along the length direction of the center magnetic yoke. A back magnetic yoke, an endless magnetic yoke composed of a pair of side magnetic yokes provided at both ends of the center magnetic yoke and the back magnetic yoke and connecting the center magnetic yoke and the back magnetic yoke, and the center magnetic yoke. Assuming an optical recording / reproducing apparatus provided with a magnet that is arranged along the length direction and that forms a magnetic force line toward the center magnetic yoke side, the center magnetic yoke in the endless magnetic yoke is provided with a first seek coil and a first seek coil. Two-seek coil The energizing magnetic field low that reduces the yoke-side energizing magnetic field generated from the center magnetic yoke side with energizing It is characterized in that a means.

The invention according to claim 2 is characterized in that the energizing magnetic field reducing means is constituted by a conductive trough cover provided on the outer peripheral surface of the center magnetic yoke along the length direction thereof. According to a third aspect of the present invention, the current-carrying magnetic field reducing means is one linear conductor wound uniformly on the outer peripheral surface of the center magnetic yoke along the length direction thereof through an electric insulator. The invention according to claim 4 is characterized in that the linear conductor comprises a magnetic field adjustment drive circuit that applies a current in a direction opposite to the direction in which the first seek coil and the second seek coil are energized. A plurality of linear conductors, in which the energizing magnetic field reducing means is divided and wound around the outer peripheral surface of the center magnetic yoke along the length direction through an electric insulator, and the linear conductors provided corresponding to the respective linear conductors. To the conductor The first seek coil and the second seek coil It is characterized in that is constituted by a plurality of magnetic field adjusting drive circuit for energizing the current flowing direction and opposite to Le.

In the technical means as described above, as the constituent materials of the conductive coating and the linear conductor provided on the outer peripheral surface of the center magnetic yoke, copper, silver, platinum, and a copper alloy,
Metallic materials such as iron-based alloys and aluminum-based alloys can be applied.

As a method of forming the above-mentioned covering body, for example, it may be formed directly on the outer peripheral surface of the center magnetic yoke by a film forming means such as a vapor deposition method, or the above-mentioned metallic material is processed into a cylindrical body, and this cylindrical body is processed. May be fitted to the center magnetic yoke, and the method of forming the same may be arbitrary.

Next, when energizing the first seek coil and the second seek coil based on the tracking error signal and the seek control signal, if the phases of the currents flowing in the coils are out of phase, the focus adjustment movable part and the carriage part move. Timing may be easily misaligned, and resonance between the focus adjustment movable portion and the carriage portion may occur. Therefore, in order to prevent this resonance phenomenon, a first drive circuit that energizes the first seek coil and a second drive circuit that energizes the second seek coil are provided, and between the first seek coil and the second seek coil. Either do not form a closed circuit, or provide a common drive circuit that energizes the first seek coil and the second seek coil, and connect the first seek coil and the second seek coil in series to this common drive circuit. It is advisable to connect them so that the phases of the currents do not shift.

In addition, a first driving force (f _s1 ) that acts on the focus adjustment movable part when the first seek coil is energized and a second driving force (f _s2 ) that acts on the carriage part when the second seek coil is energized. In the case of setting, in order to more reliably prevent the resonance phenomenon between the focus adjustment movable portion and the carriage portion, the following conditions may be set.

That is, when the weight of the focus adjustment movable portion is m and the weight of the carriage portion is M, it is preferable to set the relational expression of f _s1 / fs ₂ = m / M.

In this case, in a device that energizes each seek coil with two independent first and second drive circuits, the number of turns of each seek coil, the amplitude value of the current flowing to each seek coil, and each seek adjustment The above relationship can be set by appropriately adjusting the magnetic force strength of the magnets. On the other hand, in the device using one common drive circuit, unlike the former device, the amplitude value of the current flowing to each seek coil can be set. Since they cannot be adjusted separately, the above relationship can be set by appropriately adjusting the number of turns of each seek coil and the magnetic strength of each seek adjustment magnet.

Further, a focus adjustment magnet and a seek adjustment magnet are provided for the focus coil and the first seek coil provided in the focus adjustment movable portion, and the second seek coil provided in the carriage portion, respectively. Although it is necessary to form magnetic force lines toward the coil, these magnetic force lines may be formed by one common magnet. By adopting such a configuration, the number of parts can be reduced and the device can be downsized.

When the focus adjustment movable unit and the carriage unit are assembled to form an optical recording / reproducing apparatus, the focus adjustment movable unit is restricted due to the shape limitation of each focus adjustment movable unit and the carriage unit, the limitation of processing accuracy, and the like. A non-uniform gap may occur between the first seek coil and the second seek coil in the focus adjustment movable part and the carriage part, and the resonance caused by the non-uniform gap occurs. I have something to do.

In such a case, it is preferable to provide a magnetic fluid between the focus adjustment movable portion and the carriage portion so as to fill the gap between the focus adjustment movable portion and the carriage portion. The magnetic fluid is mainly composed of liquid such as alkylnaphthalene, synthetic oil and paraffin, and magnetic powder such as Fe ₃ O ₄ and ferromagnetic metal / alloy mixed in the liquid. Specifically, the product "MARPO Magna" (manufactured by Matsumoto Yushi-Seiyaku Co., Ltd.) or the like can be applied. As a means for holding the magnetic fluid, a method of holding it by a permanent magnet or the like attached to the carriage portion or the focus adjustment movable portion can be used.

[Operation] According to the invention of claim 1, the center magnetic yoke in the endless magnetic yoke is provided with the energizing magnetic field reducing means, and the energization of the first seek coil and the second seek coil occurs from the center magnetic yoke side. Since the yoke-side energizing magnetic field is reduced, the influence of the yoke-side energizing magnetic field is reduced, and the magnetic field distribution from the magnet acting on the first seek coil and the second seek coil is distributed to the first seek coil and the second seek coil. It is possible to hold the coil evenly regardless of whether or not the coil is energized.

According to the second aspect of the invention, the energizing magnetic field reducing means is formed of a conductive coating provided on the outer peripheral surface of the center magnetic yoke along the length direction thereof.

That is, a coil magnetic field is generated from each seek coil side along with the energization of the first seek coil and the second seek coil, and the movement of the carriage part on which the first seek coil and the second seek coil are mounted is moved. Due to the accompanying electromagnetic induction action, a current flows in a direction opposite to the energization direction of each seek coil on the surface of the coating body. Generated, and as a result, the yoke-side energizing magnetic field is reduced, and the magnetic field distribution from the magnets acting on the first seek coil and the second seek coil is determined by whether or not the first seek coil and the second seek coil are energized. It is possible to hold them evenly.

On the other hand, according to the third aspect of the present invention, the current-carrying magnetic field reducing means is one linear conductor wound uniformly along the length direction on the outer peripheral surface of the center magnetic yoke via the electric insulator. And a magnetic field adjustment drive circuit that applies a current to the linear conductor in a direction opposite to the direction of current flow to the first seek coil and the second seek coil. An energizing magnetic field in the opposite direction to that of the magnet is generated, and as a result, the energizing magnetic field on the yoke side is reduced and the magnetic field distribution from the magnets acting on the first seek coil and the second seek coil is distributed to the first seek coil and the second seek coil. It is possible to hold the coil evenly regardless of whether or not the coil is energized. According to the invention of claim 4, the energizing magnetic field reducing means is provided on the outer peripheral surface of the center magnetic yoke via an electric insulator. Along the length A plurality of linear conductors wound in a divided manner, and to each linear conductor provided corresponding to each linear conductor, an electric current in the direction opposite to the energizing direction to the first seek coil and the second seek coil is applied. Since it is composed of a plurality of magnetic field adjusting drive circuits that conduct electricity, a conducting magnetic field in the direction opposite to the yoke-side conducting magnetic field is generated from the linear conductor, and as a result, the yoke-side conducting magnetic field is reduced and the first seek The magnetic field distribution from the magnet acting on the coil and the second seek coil can be maintained evenly regardless of whether or not the first seek coil and the second seek coil are energized.

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

◎ First Embodiment An optical recording / reproducing apparatus according to this embodiment is shown in FIGS.
As shown in the figure, the focus adjustment movable part (p), the carriage part (s) on which the focus adjustment movable part (p) is mounted, and the carriage part (s) and the focus adjustment movable part (p) are connected. The leaf spring (t) and a pair of endless magnetic yokes (5) and permanent magnets (6) arranged in the radial direction of the optical recording medium (not shown) constitute the main part.

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

Further, the endless magnetic yoke (5) includes the bobbin (31).
A center magnetic yoke (51) which is inserted in the cylindrical portion of the center magnetic yoke (51) with a gap ensuring a focus movement amount, and a back magnetic yoke (51) arranged along the length direction of the center magnetic yoke (51). 52) and a pair of side magnetic yokes (53) provided on both ends of the center magnetic yoke (51) and the back magnetic yoke (52) to connect the center magnetic yoke (51) and the back magnetic yoke (52). (54) and a uniform magnetic field toward the first seek coil (41) and the second seek coil (42) on the side of the center magnetic yoke (51) of the back magnetic yoke (52). And a permanent magnet (6) for forming a magnet, and a cylinder as an energizing magnetic field reducing means formed on the outer peripheral surface of the center magnetic yoke (51) in a copper-based metal along its length direction. -Shaped short ring (55) is fitted To have.

On the other hand, the carriage portion (s) has a carriage main body (7) whose upper and lower surfaces are substantially open, bobbins (32) attached to front and rear ends of the carriage main body (7), and bobbins (32). ) Second seek coil (42)
The main portion is constituted by and the center magnetic yoke (51) is inserted into the cylindrical portion of the bobbin (32). Bearings (71) are attached to the upper and lower ends of the carriage body (7) at four positions respectively, and the bearings (71) are arranged in parallel with the center magnetic yoke (51) on a rail (50). ), The carriage portion (s) moves along the radial direction of the optical recording medium.

The leaf spring (t) is made of a spiral metal material, the inside of which is the lens holder (d) in the focus adjustment movable portion (p), and the outside of which is the carriage portion (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 adjustment section (p) and the second seek coil (42) in the carriage section (s) have a first drive circuit (81) and a second drive coil (81) as shown in FIG. Two drive circuits (82) are provided respectively.

That is, the first drive circuit (81) and the second drive circuit (82) are connected in parallel to the control signal generation circuit (80) that outputs a tracking error signal and a seek control signal, and These first drive circuit (81) is provided between the first drive circuit (81) and the first seek coil (41) and between the second drive circuit (82) and the second seek coil (42). A gain adjustment first circuit (91) and a gain adjustment second circuit (92) that increase or decrease the amplitude value of the current supplied from the second drive circuit (82) are provided. These gain adjustment first circuit (91) ) And a gain adjustment second circuit (92) to appropriately adjust the values of the first drive force (f _s1 ) and the second drive force (f _s2 ) acting on the focus adjustment movable part (p) and the carriage part (s). You can do it.

In the optical recording / reproducing apparatus configured as described above,
Focused light from a light source (not shown) provided on the apparatus main body side is incident on the objective lens (1) via a reflection prism (72), and the focused light is converted into an optical recording medium (not shown) by the objective lens (1). The information is recorded, reproduced, and erased by being converged on the convergence surface of (1).

In this optical recording / reproducing apparatus, when the first drive circuit (81) and the second drive circuit (82) are electrically connected to the first seek coil (41) and the second seek coil (42), the bobbins (31) (1) Seek coil (41) wound around (32)
And the electromagnetic force of the permanent magnet (6) acts on the second seek coil (42), and as shown in the mechanical equivalent diagram of FIG. 7, the first drive force (f _{s1 is} applied to the focus adjustment movable part (p). )But,
Further, while the second driving force (f _s2 ) acts on the carriage portion (s) to perform seek control and tracking control,
When the focus coil (40) is energized, the electromagnetic force of the permanent magnet (6) acts on the focus coil (40), and the focus adjustment movable part (p) is driven to focus as shown in the mechanical equivalent diagram of FIG. The force (f _f ) acts to perform focus control.

Here, in this optical recording / reproducing apparatus, the center magnetic yoke (51) is provided with the short ring (55) as an energizing magnetic field reducing means on the outer peripheral surface thereof. 6) It has an advantage that the disturbance phenomenon of the uniform magnetic field from 6) can be prevented.

That is, during seek control and tracking control,
When electricity is applied to the first seek coil (41) and the second seek coil (42) from the first drive circuit (81) and the second drive circuit (82), respectively, the seek coils (41) (4)
2) The coil magnetic field is generated from the side. Then, the center magnetic yoke (51) is magnetized by this coil magnetic field, and a yoke side energizing magnetic field is generated from the center magnetic yoke (51) side. Therefore, a uniform magnetic field from the permanent magnet (6) is generated by the yoke side energizing magnetic field. It is easily disturbed.

However, in the optical recording / reproducing apparatus according to this embodiment, since the center magnetic yoke (51) is provided with the short ring (55) as described above, the first magnetic field is generated under the condition where the coil magnetic field is formed. When the carriage part (s) carrying the seek coil (41) and the second seek coil (42) is moved, the electromagnetic induction causes the movement of the carriage part (s) to move the short rig (55) as shown in FIG. ) On the surface, an electric current flows in the direction opposite to the current flowing direction of each seek coil (41) (42), and the current flowing in the opposite direction generates a current flowing field in the short ring (55) that is opposite to the current flowing in the yoke side. To do. Then, since the energizing magnetic field from the short ring (55) and the yoke-side energizing magnetic field cancel each other,
As shown in the figure, since the yoke side energizing magnetic field can be reduced, the first seek coil (41) and the second seek coil (42)
This has the advantage that the magnetic field distribution from the permanent magnet (6) that acts on the first seek coil (41) and the second seek coil (42) can be maintained evenly regardless of the presence or absence of energization. is doing.

Therefore, the gain adjustment first circuit (91) and the gain provided between the first seek coil (41) and the second seek coil (42) and the first drive circuit (81) and the second drive circuit (82) The adjustment second circuit (92) is adjusted as appropriate to adjust the ratio (f _s1 ) of the driving force between the first driving force (f _s1 ) and the second driving force (f _s2 ).
/ F _s2 ) is set to be f _s1 / f _s2 = m / M (where m is the mass of the focus adjustment movable part and M is the mass of the carriage part),
Since the above relationship is always maintained in the central region of the center magnetic yoke (51) and also in the regions of the side magnetic yokes (53) and (54), the focus adjustment movable portion (p) and the carriage portion (s). ) And leaf spring (t)
It is possible to prevent the resonance phenomenon caused by
It has the advantage that the mechanical vibration characteristics required for tracking, seek control, etc. can be obtained.

Moreover, in the optical recording / reproducing apparatus according to this embodiment, the first drive circuit (81) for energizing the first seek coil (41) and the second drive circuit (82) for energizing the second seek coil (42). Is provided so that a closed circuit is not formed between the first seek coil (41) and the second seek coil (42), and the phase of the current flowing through each seek coil (41) (42) does not shift. Therefore, there is an advantage that the resonance phenomenon between the focus adjustment movable part (p) and the carriage part (s) can be more surely prevented.

Therefore, the focus adjustment movable part (p) and the carriage part (s) can always be integrally moved regardless of the frequency value of the current flowing through the seek coils (41) and (42), so that it is possible to perform accurate operation. This has the advantage that reliable seek and tracking control can be performed reliably.

FIG. 8 is a graph showing the relationship between the vibration in the seek direction of the focus adjustment movable part (p) and the frequency when the focus adjustment movable part (p) and the carriage part (s) are vibrating. FIG. 9 is a graph showing the relationship between the phase of the focus adjustment movable part (p) and the frequency when the focus adjustment movable part (p) and the carriage part (s) are vibrating. It can be confirmed from these graphs that the resonance phenomenon does not occur.

◎ Second Embodiment An optical recording / reproducing apparatus according to this embodiment is shown in FIGS.
As shown in the figure, a line conductor (56) is provided on the outer peripheral surface of the center magnetic yoke (51) in place of the short ring (55) as a means for reducing the applied magnetic field, and the line conductor (56) is energized. The optical recording and reproducing apparatus according to the first embodiment is substantially the same as the optical recording and reproducing apparatus according to the first embodiment except that a magnetic field adjustment drive circuit (85) is provided.

That is, the linear conductor (56) is made of a copper-based linear metal, and is uniformly wound on the outer peripheral surface of the center magnetic yoke (51) over the lengthwise direction thereof through an electric insulating layer (not shown). The magnetic field adjustment drive circuit (85) is provided in parallel with the control signal generation circuit (80), like the first drive circuit (81) and the second drive circuit (82). A signal inversion circuit (84) connected to invert an output signal from the control signal generation circuit (80) and the linear conductor (5).
6) First seek coil (41) and second seek coil (4)
2) A linear conductor drive circuit (83) for passing a current in the direction opposite to the current-carrying direction, and a gain adjustment third circuit () for increasing or decreasing the amplitude value of the current supplied from this linear conductor drive circuit (83). 9
3) is composed of and.

In the optical recording / reproducing apparatus according to this embodiment, the linear conductor (56) wound around the outer peripheral surface of the center magnetic yoke (51) and the seek coil (56) for the linear conductor (56). 41) Since the magnetic field adjustment drive circuit (85) for supplying a current in the opposite direction to the current supply direction to (42) is provided, seek control and tracking are performed as in the optical recording / reproducing apparatus according to the first embodiment. It has an advantage that the disturbance phenomenon of the uniform magnetic field from the permanent magnet (6) at the time of control can be prevented.

That is, during seek control and tracking control,
Even if the center magnetic yoke (51) is magnetized by the energization of the first seek coil (41) and the second seek coil (42) and a yoke side energizing magnetic field is generated from the center magnetic yoke (51) side, Synchronously, as shown in FIG. 12, the magnetic field adjustment drive circuit (85) supplies a current to the linear conductor (56) in the opposite direction to the current flowing to each seek coil (41) (42). As a result, a current-carrying magnetic field in the direction opposite to the yoke-side current-carrying magnetic field is generated from the linear conductor (56), so that the current-carrying magnetic field and the yoke-side current-carrying magnetic field can be canceled out to reduce the yoke-side current-carrying magnetic field. The magnetic field distribution from the permanent magnet (6) acting on the seek coil (41) and the second seek coil (42) is determined by whether or not the first seek coil (41) and the second seek coil (42) are energized. It has the advantage that it can be held evenly.

Moreover, in the optical recording / reproducing apparatus according to the present embodiment, the yoke side energizing magnetic field can be set to the minimum by appropriately adjusting the energizing amount to the linear conductor (56), and thus the first seek coil (41) And the magnetic field distribution from the permanent magnet (6) acting on the second seek coil (42) can be maintained more evenly.

Therefore, in both the central region of the center magnetic yoke (51) and the regions on the side magnetic yokes (53) (54) side, the driving force ratio, that is, f _s1 / f
_Since the relationship of _s2 = m / M is maintained, it is possible to prevent the resonance phenomenon generated by the focus adjustment movable part (p), the carriage part (s), and the leaf spring (t), and seek and track. It has the advantage that the mechanical vibration characteristics required for control and the like can be obtained.

◎ Third Embodiment An optical recording / reproducing apparatus according to this embodiment is shown in FIGS.
As shown in the figure, a plurality of linear conductors (56) are provided on the outer peripheral surface of the center magnetic yoke (51) in place of the short ring (55) as the energizing magnetic field reducing means, and the linear conductor (56). ) Is substantially the same as the optical recording / reproducing apparatus according to the first embodiment except that a plurality of magnetic field adjustment drive circuits (85) for energizing the magnetic field are provided.

That is, each of the linear conductors (56) is made of a copper-based linear metal, and is arranged in a predetermined area of the outer peripheral surface of the center magnetic yoke (51) in the length direction thereof through an electric insulating layer (not shown). The magnetic adjustment drive circuit (85) is wound around the control signal generation circuit (80) like the first drive circuit (81) and the second drive circuit (82).
A signal inverting circuit (84) connected in parallel with respect to the control signal generating circuit (80) for inverting an output signal from the control signal generating circuit (80), and a first seek coil (41) and a second seek coil (41) to the linear conductor (56). 42) A linear conductor drive circuit (83) for passing a current in a direction opposite to the current-carrying direction, and this linear conductor drive circuit (83)
And a gain adjustment third circuit (93) for increasing / decreasing the amplitude value of the current supplied by.

Further, in the optical recording / reproducing apparatus according to this embodiment, a plurality of linear conductors (56) divided and wound around the outer peripheral surface of the center magnetic yoke (51) and each linear conductor (56).
Since the first seek coil (41) and the second seek coil (42) are provided with a plurality of magnetic field adjustment drive circuits (85) for passing a current in the opposite direction to the current-carrying direction, the first embodiment and the Similar to the optical recording / reproducing apparatus according to the second embodiment, the disturbance phenomenon of the uniform magnetic field from the permanent magnet (6) at the time of seek control or tracking control can be prevented, and therefore the mechanical required for seek, tracking control, etc. It has an advantage that vibration characteristics can be obtained.

In particular, the optical recording / reproducing apparatus according to this embodiment is provided with a plurality of linear conductors (56) independent of each other and a plurality of magnetic field adjustment drive circuits (85) for energizing the linear conductors (56). Since the drive circuit (85) can energize only the linear conductor (56) at a required portion, there is an advantage that power consumption can be reduced.

[Effects of the Invention] According to the inventions according to claims 1 to 4, the influence of the energizing magnetic field on the yoke side is reduced, and the magnetic field distribution from the magnets acting on the first seek coil and the second seek coil is determined by the first seek. It is possible to hold the coil and the second seek coil evenly regardless of the presence or absence of energization.

Therefore, the strength of the electromagnetic force acting on the first seek coil and the strength of the electromagnetic force acting on the second seek coil can be controlled to a desired set value at all times, so that accurate seek and tracking control can be reliably performed. ing.

Further, according to the invention of claim 2, the energizing magnetic field reducing means is constituted by a conductive coating provided on the outer peripheral surface of the center magnetic yoke along the length direction thereof. The present invention has an effect that accurate seek and tracking control can be performed without complicating the structure as compared with the device. On the other hand, according to the invention of claim 3, the energizing magnetic field reducing means is provided with a center magnetic field through an electric insulator. One linear conductor uniformly wound around the outer peripheral surface of the yoke along its length, and a current flowing in the linear conductor in a direction opposite to the direction of current flow to the first seek coil and the second seek coil. It is possible to control the strength of the energizing magnetic field in the opposite direction to the yoke-side energizing magnetic field by adjusting the amount of energization to the linear conductor. To further reduce According to the invention of claim 4, the seek and tracking control can be performed more accurately, and the outer peripheral surface of the center magnetic yoke is provided on the outer peripheral surface of the center magnetic yoke via the electrical insulator of the energizing magnetic field reducing means. A plurality of linear conductors that are divided and wound along the length direction, and the direction of energization of the first seek coil and the second seek coil to each linear conductor that is provided corresponding to each linear conductor It is composed of a plurality of magnetic field adjustment drive circuits that pass a current in the opposite direction, and by adjusting the amount of current to each linear conductor, the strength of the current flowing in the direction opposite to that of the yoke side can be controlled as appropriate. Since the influence of the magnetic field can be further reduced, the seek and tracking control can be performed more accurately, and a plurality of magnetic field adjustment drive circuits are provided, which are required by these magnetic field adjustment drive circuits. Since only it is possible to energize the linear conductor of a site, it has the effect of reducing power consumption can be reduced.

[Brief description of drawings]

1 to 15 show an embodiment of the present invention. FIG. 1 is a partially cutaway perspective view of an optical recording / reproducing apparatus according to the first embodiment, and FIG. 2 is II- of FIG. II plane sectional view, FIG. 3 is a partial perspective view showing the positional relationship between the first seek coil and the focus coil provided in the focus adjustment movable portion, the second seek coil provided in the carriage portion, and the endless magnetic yoke. FIG. 4 is a circuit diagram showing a method of energizing the first seek coil and the second seek coil, and FIG. 5 is a partially enlarged perspective view of the center magnetic yoke, the short ring, and the first seek coil or the second seek coil. FIG. 6 is a schematic plan view of FIG. 3, FIG. 7 is a mechanical equivalent view of this apparatus, and FIG. 8 is a graph showing the relationship between the amplitude and frequency of the focus adjustment movable part in the seek direction in this apparatus. Fig. 9 and Fig. 9 show the system of the focus adjustment movable part. It is a graph showing the relationship between the phase and the frequency of the direction of the square, also, FIG. 10 is a partially cutaway perspective view of the optical recording and reproducing apparatus according to the second embodiment, FIG. 11 is a first seek coil, A circuit diagram showing a method of energizing the second seek coil and the linear conductor, and FIG. 12 is a schematic diagram showing a relationship between the first seek coil, the second seek coil, the endless magnetic yoke, and the linear conductor. FIG. 13 is a plan view, and FIG. 13 is a partially cutaway perspective view of the optical recording / reproducing apparatus according to the third embodiment.
FIG. 14 is a schematic plan view showing the relationship between the first seek coil, the second seek coil, the endless magnetic yoke, and the linear conductor, and FIG. 15 is the first seek coil, the second seek coil, And, it is a circuit diagram showing a method of energizing the linear conductor, also, FIGS. 16 to 25 show a conventional example,
FIG. 16 is a schematic view of the configuration of the optical recording / reproducing apparatus, FIG. 17 is a plan view of the optical recording / reproducing apparatus incorporating a drive system, FIG. 18 is a sectional view taken along the line XVIII-XVIII of FIG. 17, and FIG. Is a mechanical equivalent diagram of this device, FIG. 20 is a graph showing the relationship between the amplitude and frequency in the seek direction of the focus adjustment movable part in this device, and FIG. 21 is the phase in the seek direction of the focus adjustment movable part. FIG. 22 is a graph showing the relationship with frequency, FIG. 22 is a partially cutaway perspective view of a conventional optical recording / reproducing apparatus having a first seek coil and a second seek coil, and FIG. 23 shows a focus adjustment movable part. Partial perspective view showing the positional relationship between the first seek coil and focus coil provided, and the second sequel provided in the carriage section, and the endless magnetic yoke, FIG. 24 is a mechanical equivalent diagram of this device, FIG. 25 shows a schematic plan view of FIG. 23, respectively. To have. [Explanation of symbols] (1) …… Objective lens (2) …… Lens holder (5) …… Endless magnetic yoke (6) …… Permanent magnet (7) …… Carriage body (31) (32) …… Bobbin (40) …… Focus coil (41) …… First seek coil (42) …… Second seek coil (51) …… Center magnetic yoke (52) …… Back magnetic yoke (53) (54) …… Side Magnetic yoke (55) ...... Short ring (56) ...... Linear conductor (85) ...... Magnetic field adjustment drive circuit (p) ...... Focus adjustment movable part (s) ...... Carriage part (t) ...... Leaf spring

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kaoru Yasukawa 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.Ebina Business Office (72) Inventor Daisuke Iguchi 2274 Hongo, Ebina City, Kanagawa Fuji Xerox Co., Ltd.Ebina Business In-house

Claims (4)

[Claims] 1. An objective lens arranged near an optical recording medium for converging focused light from a light source to a converging surface of the optical recording medium,
A focus coil for driving the objective lens in a direction substantially perpendicular to the surface of the optical recording medium by an electromagnetic force accompanying energization, and a first seek coil for driving the objective lens in a radial direction of the optical recording medium by an electromagnetic force accompanying energization. A main part of the focus coil and a first coil support part that supports the first seek coil are formed, and these objective lens, focus coil, first seek coil, and first coil support part are integrated. A focus adjustment movable part fixed to the carriage, a carriage main body on which the focus adjustment movable part is mounted so as to be movable in the radial direction of the optical recording medium, and a second coil support part of the carriage main body, which is provided with energization. A carriage part, the main part of which is composed of a second seek coil that drives the carriage body in the radial direction of the optical recording medium by electromagnetic force, and one end The other end of the focus adjustment movable portion is fixed to the carriage portion, and a leaf spring that supports the focus adjustment movable portion in a state of being movable in a direction substantially perpendicular to the surface of the optical recording medium; A center magnetic yoke, which is inserted through the insertion portion formed in the coil support portion and the second coil support portion of the carriage portion and is arranged in the radial direction of the optical recording medium, and along the length direction of the center magnetic yoke. A back magnetic yoke provided, an endless magnetic yoke composed of a center magnetic yoke and a pair of side magnetic yokes provided at both ends of the back magnetic yoke and connecting the center magnetic yoke and the back magnetic yoke; An optical recording / reproducing apparatus including a magnet which is arranged along the length direction of the yoke and forms a magnetic force line toward the center magnetic yoke side. In the endless magnetic yoke, the center magnetic yoke is provided with an energizing magnetic field reducing means for reducing the yoke-side energizing magnetic field generated from the center magnetic yoke side with the energization of the first seek coil and the second seek coil. An optical recording / reproducing apparatus characterized by. 2. The energizing magnetic field reducing means is constituted by a conductive coating provided on the outer peripheral surface of the center magnetic yoke along the length direction thereof. An optical recording / reproducing apparatus according to the item. 3. A linear conductor, wherein the energizing magnetic field reducing means is uniformly wound around an outer peripheral surface of a center magnetic yoke in the length direction of the center magnetic yoke via an electric insulator, and to the linear conductor. The optical recording / reproducing apparatus according to claim 1, wherein the optical recording / reproducing apparatus comprises a magnetic field adjustment drive circuit that applies a current in a direction opposite to the direction of current application to the first seek coil and the second seek coil. 4. A plurality of linear conductors, in which the energizing magnetic field reducing means is divided and wound around an outer peripheral surface of a center magnetic yoke in the lengthwise direction through an electric insulator, and each linear conductor is supported. And a plurality of magnetic field adjustment drive circuits for supplying a current in a direction opposite to the direction of current flow to the first seek coil and the second seek coil to each linear conductor. 1. The optical recording / reproducing apparatus according to item 1.