JPS5927989B2 - Regeneration needle drive device for information signal regeneration element - Google Patents

Description

[Detailed Description of the Invention] In recent years, high-density recording and reproduction of various information signals have been performed using information recording media disks (hereinafter sometimes abbreviated as disks).
It is well known that research and development efforts have been actively conducted to improve the recording and reproduction of information signals using disks, and many proposals have been made to date for high-density recording and reproduction of information signals using disks. The company has also been conducting research into high-density recording and reproducing methods for information signals using various types of disks.

As a result of considering the results of previous research, the applicant company found that the disc must be of a grooveless format so that the playback mode can be changed freely during playback, and that the information signal from the disc must be of a grooveless type. reading (detection)
Considering the fact that the capacitance change detection method is the best method and other conditions, we developed a high-density recording and reproducing method for information signals using non-groove disks (hereinafter referred to as non-groove disks). We promoted practical research on
The original form was proposed in Japanese Patent Application No. 52-13322 (see Japanese Patent Publication No. 57-32415) and many other proposals as a result of subsequent practical research.

As clarified in the above-mentioned information signal recording, reproduction method, etc. proposed by the applicant company, the applicant company &. By arranging pits corresponding to the main information signals in a spiral or concentric pattern on a flat surface,
Spiral or concentric recording marks (tracks) are formed on a flat surface at predetermined intervals (track pitches) and by an arrangement of pits corresponding to the above-mentioned main information signals. A region (space) is formed between adjacent tracks (hereinafter sometimes referred to as main information signal tracks) in which pits corresponding to the main information signal do not exist. At the same time, pits corresponding to tracking control signals are arranged continuously or intermittently in the spiral or concentric space formed between the adjacent tracks in each phase, and the tracking control signal is arranged in the space in a continuous or intermittently manner. Forming a spiral or concentric track (hereinafter sometimes abbreviated as a tracking control signal track) by an arrangement of pits corresponding to the control signal, and pits corresponding to the above-mentioned main information signals; The tracking control signal and the corresponding pit are arranged so that the recording pattern is such that they overlap each other to some extent in the width direction of the pit, and the frequency values of the tracking control signal and the corresponding pit are mutually overlapped. 1 of the disk using two different signals.
The two signals are alternately switched at a specific position (rotational phase) of the disk every rotation, and one of the two signals is used to continuously or intermittently track the pits corresponding to the control signal. This constitutes a disk on which a track is formed, and the reproduction of the main information signal from the disk is performed using the pit width of the pit corresponding to the main information signal (corresponding to the main information signal) in the disk. The electrode 4a has an electrode width (regenerated width) that is approximately the same as the track width (same as the track width of the track formed by the pit), and is in contact with the surface of the disk with a contact width wider than the track pitch in the width direction of the track. For example, a plurality of information signals recorded on a disk using a reproducing needle (scanning needle) as shown in Japanese Patent Application No. 52-22764 (see Japanese Patent Application Laid-Open No. 53108413). This is done by detecting changes in the capacitance between each information signal formed on the electrode and the disk and the corresponding pit. The signal obtained from the tracking control signal tracks formed on both sides of the signal track is used as the tracking control signal, and the operation of the tracking servo system aligns the center of the electrode in the reproducing needle with the center of the main information signal track. I proposed something that would always match.

When reproducing information signals from the above-mentioned grooveless disc, tracking is performed by the operation of a tracking servo system so that the reproduction needle always accurately tracks the recording trace to be reproduced. Needless to say, the regenerating needle is required to be controlled, and the regenerating needle is driven and displaced by a tracking control drive device in a tracking servo system.

Furthermore, although disks are designed to be rotated accurately at a predetermined number of rotations when reproducing information signals, disks are inevitably subject to mechanical deformation due to various other causes during manufacturing. Even if it is rotated at a constant number of rotations during playback, the relative speed between the recording trace and the playback needle will change due to the presence of the mechanical deformation described above. This causes a so-called time axis error (jitter) to be included in the reproduced signal.

For this reason, conventionally, a time axis error correction signal obtained by comparing a reference signal in the reproduction signal with a standard signal is applied to one drive device of the time axis error correction control circuit of the reproduction needle, and thereby the reproduction needle is driven and displaced in the direction of extension of the recorded trace to prevent time axis errors from occurring in the reproduced signal.

Therefore, when reproducing information signals from a grooveless disc, there are two types of control: time axis error correction control and tracking control.
It is necessary to drive and displace the reproducing needle two-dimensionally in both the extending direction of the recorded trace and the direction orthogonal thereto by one control.

Therefore, the applicant company first completed a regeneration stylus drive device that can drive and displace the regeneration stylus two-dimensionally during regeneration of grooveless discs, and achieved the expected results by implementing the device. However, subsequent research revealed that it was necessary to complete a regenerated needle drive device with even more excellent characteristics.

That is, in the above-mentioned reproducing needle drive device of the information signal reproducing element manufactured by the applicant company, a permanent magnet is attached to a movable member including a cantilever to which a reproducing needle is fixed, and the current flowing through the permanent magnet and the excitation coil is Since the movable member is driven by the electromagnetic force generated between the In some cases, the larger the magnetic force of the permanent magnet is, the greater the magnetic force becomes. On the other hand, in order to perform tracking control and time axis error correction control for the reproduction needle well, it is necessary to Since the reproducing needle must have good follow-up characteristics, one drive system for driving the reproduction needle must exhibit a high resonant frequency.

However, when a cantilever is used to perform a tracking operation, it causes transverse resonance in a high frequency range, and the limit of tracking performance is determined at this point, so it is necessary to improve tracking performance up to even higher frequencies. In order to achieve this, it is necessary to increase the stiffness of the cantilever, but an increase in stiffness necessarily results in an increase in the moment of inertia of the cantilever.

In order to obtain the same amount of drive displacement of the cantilever whose moment of inertia has increased as described above with the same driving power as when performing tracking control without increasing the moment of inertia, it is necessary to The permanent magnet that should be installed on the other hand has a large magnetic force, that is, a large volumetric shape, and as a result, the moment of inertia of the cantilever increases slightly. This has caused a problem in that the surface runout tracking characteristics of the disk deteriorate due to this, and in some cases, the desired tracking control cannot be performed.

In order to solve this problem, the applicant company first decided to
The reproduction needle that reads information signals from the recording traces on the information recording medium disk is driven and displaced in the direction of extension of the recording traces in accordance with the time axis error correction signal, and the reproduction needle is driven in the direction of extension of the recording traces in accordance with the correction signals for tracking control. A reproducing needle driving device for an information signal reproducing element configured to displace the information signal reproducing element by one drive in a direction perpendicular to the reproducing needle includes a movable member supported by a support body so as to be able to be freely displaced integrally with the reproducing needle, and a hollow member, respectively. In a state where two coils are wound into a cylindrical shape and the two coils are arranged side by side and fixed to the support body, each of the two coils is fixed to the support body. A first space portion into which a portion on one side of the coil is to be inserted, and a second space portion into which a portion on the other side of each of the two coils is to be inserted. The first space is a space where a strong magnetic field is formed by arranging pairs of magnetic poles of different polarities in the direct current magnetic field forming member to face each other. In addition, the above-mentioned second space portion is made up of a DC magnetic field forming member in which magnetic poles of only one polarity are arranged opposite each other in the DC magnetic field forming member. However, in this existing proposal, when two coils are driven by a correction signal for tracking control and a correction signal for time axis error, , a problem arises in that it is necessary to perform arithmetic processing on both of the above-mentioned correction signals.

The present invention drives and displaces a playback needle that reads information signals from a recording trace on an information recording medium disc in the direction of extension of the recording trace in accordance with a time axis error correction signal, and also drives and displaces a reproduction needle that reads an information signal from a recording trace on an information recording medium disc in a recording trace extension direction in accordance with a correction signal for tracking control. In a playback needle drive device for an information signal playback element that is driven and displaced in a direction perpendicular to the direction in which the trace extends, the device is connected and fixed to a movable member that is supported so as to be freely displaceable integrally with the playback needle. At least three or more coils are provided, and the at least three or more coils are a first coil set made up of two specific coils among them, and a second coil set made up of the remaining coils. Each of the coils belonging to the first coil group is made stronger by arranging each pair of magnetic poles of different polarity in the DC magnetic field forming member so that one side of each coil faces each other. The other side portion of each coil in each coil belonging to the first coil set is disposed in the first space where a magnetic field is formed, and the other side portion of each coil is disposed in the first space where a magnetic field is formed. A strong magnetic field is formed by arranging each pair of magnetic poles of different polarity in the forming member to face each other.
Further, all the coils belonging to the second coil group are arranged in the first space of the DC magnetic field forming member. , the above-mentioned first coil set of coils, and
A reproduction stylus drive device for an information signal reproducing element in which the coils of the second coil group described above and the DC magnetic field forming member described above are disposed, and a reproduction stylus that reads information signals from recording traces on an information recording medium disk. is driven to be displaced in the direction of extension of the recorded trace in response to a correction signal for the time axis error, and also displaced by one drive in a direction perpendicular to the direction of extension of the recorded trace in response to a correction signal for tracking control. A reproducing needle driving device for an information signal reproducing element, comprising at least three or more coils connected and fixed to a movable member supported so as to be freely displaceable integrally with the reproducing needle,
The above-mentioned at least three or more coils are divided into a first coil group consisting of two specific coils among them and a second coil group consisting of the remaining coils, and the above-mentioned first coil group is divided into Each coil belongs to a first space in which a strong magnetic field is formed by arranging each pair of magnetic poles of different polarity in the direct current magnetic field forming member so that one side part of each coil faces each other. As shown in FIG. The coils belonging to the second coil group are placed in the second space where a strong magnetic field is formed by arranging the coils facing each other, and each coil belonging to the second coil group is connected to the first coil group. The present invention provides a regeneration needle drive device for an information signal regeneration element that is integrally provided with a coil, thereby solving the above-mentioned problems. do.

FIG. 1 is a partially fragmented perspective view of an embodiment of the reproducing needle drive device for an information signal reproducing element of the present invention;
The figure is a plan sectional view of the same as the above, FIG. 3 is an exploded perspective view of the same as the above, and FIGS. This is a diagram.

First, in one embodiment of the reproducing needle drive device for the information signal reproducing element of the present invention shown in FIGS. 1 to 3, reference numeral 1 shows a pole piece 1a having a notch 1b protruding therefrom. The magnetic path bottom plate 2a and 2b are permanent magnets, and 3 is a magnetic path front plate.The magnetic path bottom plate 1, pole piece 1a, permanent magnets 2a and 2b, magnetic path front plate 3, etc. It constitutes a forming member. A magnetic gap 20 is formed as a first space 20 between the hole 3a bored in the magnetic path front plate 3 and the outer periphery of the pole piece 1a {see FIGS. 2 and 6 a-c}. The coils 4, 5 in three coils 4, 5, 6 are fixed to a mounting body 7 made of a non-magnetic material such as aluminum.
The semi-cylindrical surface portions forming one side portions 4h, 5h {see FIG. 2 and FIGS. 6 a-c} and the coil 6 are movably positioned, and the coils 4 and 5 described above are also movably positioned. The plane portions forming the side portions 4n, 5n {see FIG. 2 and FIGS. 6 a to c} are the second space portions 21 formed in the cutout portion 1b between the pole pieces 1a, 1a (FIG. 2). and Figure 6 a-c}
movably positioned in the magnetic field inside.

Furthermore, the mounting body 7 is integrally provided with two protrusions 7b, 7b each having a V-shaped notch for engagement, and is also provided with a screw hole 7a, as described above. A permanent magnet 11, which is a component of the magnetic coupler, is fixed to a portion of the mounting body 7 between the protrusions 7b, 7b and the screw holes 7a, 7a.

It goes without saying that the coils 4 to 6 are designed so that they do not come into sliding contact with the constituent members of the magnetic gap even when they are movable. Screw hole 7a of the mounting body 7 described above
, 7a are screwed together with mounting screws 9a, 9a which are inserted into through holes 8a, 8a of a plate spring 8 whose cross section in the plate thickness direction is a frame structure (rigid frame structure). It is integrally fixed to the three coils 4 to 6.

The plate spring 8 has through holes 8b bored on both sides thereof,
The screws 10, 10 inserted into the magnetic path front plate 3
The screw holes 3b and 3b provided on the side surface of the
It is designed so that rotation about the line connecting a and 8a as the rotation axis can be performed smoothly. Further, TT is a turntable, D is a disk, and 12 is a playback needle provided with a sliding surface that comes into sliding contact with the surface of the disk D, and this playback needle 12 is fixed to a cantilever 13.

14 is a damper, and 15 is a guide pin made of ferromagnetic material (for example, made of piano wire). By being guided by the V-shaped notches 7b and 7b, the guide pin 15 is attracted to the permanent magnet 11, and the cantilever 13 and the mounting body 7 are
are integrally connected and fixed.

The regeneration needle drive device shown in FIG. 1 (through FIG. 3) configured as described above has two coils 4 and 5 connected as a first and second coil set with appropriate connection polarities. , the coil 6 is used as a second coil set, and by passing current through the coils of the first and second coil sets, the first and second coil sets are connected to the permanent magnets 2a, 2a in the DC magnetic field forming member. The regenerating needle 1 is displaced in a direction determined depending on the magnetization method in 2b.
2 is driven and displaced both in the direction of extension of the recorded trace and in the direction perpendicular to the direction of extension of the recorded trace.

FIG. 4a is a diagram illustrating and explaining the construction principle and operating principle of the regeneration needle drive device of the embodiment shown in FIG. 1 (through FIG. 3). {In FIG. 4a, even if the polarity of the permanent magnets 2a and 2b is reversed from the illustrated state, the direction of the driving force applied from each coil set to the cantilever 1 does not change, so such Illustrations and explanations of the drive device in this case are omitted. This point is the same in the cases of FIG. 4b and FIG. 4c. In addition, in FIGS. 4a to 4c, only the coil, the DC magnetic field forming member, etc. are shown. Now, the reproducing needle driving device for the information signal reproducing element of the present invention is provided with at least three or more coils connected and fixed to a movable member supported so as to be freely displaceable integrally with the reproducing needle. At least three or more coils are divided into a first coil group consisting of two specific coils and a second coil group consisting of the remaining coils.
Each coil belonging to the coil group has one side portion of each coil (the portion of the coil indicated by a drawing code with a subscript h in the figure) that is connected to each pair of coils in the DC magnetic field forming member. A first space 20 in which a strong magnetic field is formed by arranging magnetic poles of different polarities to face each other.
As shown in FIG. The coil portion) is arranged in the second space 21 in which a strong magnetic field is formed by arranging each pair of magnetic poles of different polarity in the DC magnetic field forming member to face each other. Furthermore, all the coils belonging to the second coil group are arranged in the first space 20 of the DC magnetic field forming member. , the coils of the second coil group described above, and the DC magnetic field forming member described above, so in FIG. 4a, each coil 4 to 6 is placed. If the magnetic fields of the respective parts are as shown in the figure, and if the connection polarities of the coils 4 and 5 forming the first coil group are as shown in the figure, then the coils forming the first coil group The first coil set is driven and displaced toward the coil axis by the electromagnetic force generated between the current flowing through the coils 4 and 5 and the magnetic field, and the second coil set is When a current flows through the coils 6 that make up the set, the second coil set is moved perpendicular to a plane that includes the coil axis of the coil 6 and is parallel to the magnetic field due to the electromagnetic force generated between the current flowing through the coil 6 and the magnetic field. It will rotate around the axis.

Therefore, by supplying a time axis error correction signal to the coils constituting the coil set that is driven and displaced in the direction of the coil axis by passing a current, and by passing a current, A coil in a coil set that is driven and displaced so as to rotate around an axis that includes the coil axis of each coil that constitutes the coil set and is perpendicular to a plane that is parallel to the magnetic field.
If a correction signal for tracking control is supplied, the first
The regeneration needle driving device shown in the figures (FIG. 3) can simultaneously perform both a time axis error correction operation and a tracking control operation on the regeneration needle 1 two-dimensionally.

FIGS. 4B and 4C show that the coil 6 in the embodiment shown in FIGS.
Separate coils 6a,
This is a modified embodiment of the embodiment shown in the first figure, in which a coil 6b is added and wound, and in FIGS. 4B and 4C, the coil 4 and the coil 5 constitute a first coil set, Further, the coil 6a and the coil 6b constitute a second coil set.

The coil 4 and the coil 6a are wound integrally on the same coil bobbin in an appropriate manner such as overlapping winding, bifilar winding, or side-by-side winding while being insulated from each other. Yes, also coil 5
The coils 6b and 6b are wound integrally on the same coil bobbin in an appropriate manner such as overlapping windings, bifilar winding, or juxtaposed windings while being insulated from each other.

In the regeneration needle drive device shown in the configuration example shown in FIGS. 4B and 4C, the state of the magnetic pole in the DC magnetic field forming member and the direction of the current flowing through each coil 4, 5, 6a, 6b, etc. Assuming that the example shown in the figure is the same, the first coil set consisting of coils 4 and 5 is driven in the direction of the coil axis in the case shown in Fig. 4b, and in the case shown in Fig. 4c. In the illustrated case, the first coil set rotates around an axis perpendicular to a plane parallel to the magnetic coil including each coil axis,
Furthermore, in the case shown in FIG. 4b, the second coil set composed of the coils 6a and 6b rotates around an axis perpendicular to a plane parallel to the magnetic field including each coil axis, and furthermore, , the second coil set in the case shown in FIG. 4c is driven in the direction of the coil axis, so that the coil 4
, 5 and a second coil set consisting of coils 6a and 6b are integrally provided as shown in FIGS. If a correction signal for tracking control is supplied to one of the required ones, and a correction signal for time axis error is supplied to the other one, the results shown in FIGS. 1 (through 3) can be achieved. As in the case of the regenerating needle drive device having the above configuration, two-dimensional drive control can be performed on the regenerating needle.

As is clear from the above detailed explanation, in the reproduction needle drive device for the information signal reproduction element of the present invention, the reproduction needle is moved perpendicularly to the extending direction of the recorded trace for tracking control and time axis error correction. Since the movable parts of the drive mechanism for two-dimensional driving in the direction and the extension direction of the recorded trace are only the coil, the cantilever, and the connecting part, the mass and moment of inertia of the movable parts are small. In addition, since it is possible to use a member with a sufficiently large magnetic flux density in the magnetic gap in the part where the coil moves as the DC magnetic field forming member provided through space with respect to the movable part, the coil Since the electromagnetic force generated between the current flowing through the magnetic field and the magnetic field can be made sufficiently large, the required amount of time axis error correction and required amount of tracking control can be performed with sufficient margin. It is possible to configure a servo system that can perform servo system, and furthermore, in the DC magnetic field forming member, the direction and strength of the magnetic field in the magnetic gap where the coil moves can be set as desired, and tracking control can be performed from among multiple coils. A coil set used for
In addition to being able to select and use the coil set used for time axis error correction as necessary, the present invention also provides various advantages such as being able to select and use the coil set used for time axis error correction. The present invention has the advantage that a regeneration needle driving device that can drive the regeneration needle two-dimensionally without using an arithmetic circuit can be easily constructed.

[Brief explanation of the drawing]

FIG. 1 is a partially fragmented perspective view of an embodiment of the reproducing needle drive device for an information signal reproducing element of the present invention;
The figure is a plan sectional view of the same as the above, FIG. 3 is an exploded perspective view of the same as the above, and FIGS. FIG. 3 is a diagram for illustrating and explaining the configuration principle and operating principle of the device. 1...Magnetic path bottom plate, 1a, 21-23...
・Pole piece, 1b...Notch, 2, 2a,
2b, 11... Permanent magnet, 3... Magnetic path front plate, 4, 5, 6, 16-18... Coil,
4h; 5h... One side part of the coil, 4n, 5
n... Other side part of the coil, 7... Mounting body, 8... Leaf spring, 9... Mounting screw, 10...・Screw, 12... Recycled needle, 1
3...Cantilever.

Claims (1)

[Scope of Claims] 1. A playback needle that reads information signals from a recording trace on an information recording medium disk is driven and displaced in the direction of extension of the recording trace in accordance with a correction signal for a time axis error, and a correction signal for tracking control is In a reproducing needle drive device for an information signal reproducing element, the movable member is supported so as to be freely displaceable integrally with the reproducing needle. At least three or more coils are connected and fixed to each other, and the at least three or more coils are a first coil group consisting of two specific coils, and a second coil group consisting of the remaining coils.
Each coil belonging to the first coil group is arranged such that one side portion of each coil faces each pair of magnetic poles of different polarity in the DC magnetic field forming member. In addition, the other side portion of each coil belonging to the first coil group is arranged in the first space where a strong magnetic field is formed by doing so. Furthermore, the above-described DC magnetic field forming member is arranged in the second space where a strong magnetic field is formed by arranging each pair of magnetic poles of different polarities to face each other. All the coils belonging to the second coil group are arranged in the first space in the DC magnetic field forming member, and the coils of the first coil group and the second coil group are arranged in the first space. A reproducing needle drive device for an information signal reproducing element, comprising a coil set of coils and the above-mentioned DC magnetic field forming member. 2 Drive and displace the playback needle that reads the information signal from the recorded trace on the information recording medium disc in the direction of extending the recorded trace in accordance with the correction signal for the time axis error, and also extend the recorded trace in accordance with the correction signal for tracking control. A reproduction needle drive device for an information signal reproduction element, which is configured to drive and displace an information signal reproduction element in a direction perpendicular to the above direction, and is connected and fixed to a movable member supported so as to be freely displaceable integrally with the reproduction needle. At least three or more coils are provided, and the at least three or more coils are a first coil group consisting of two specific coils among them, and a second coil group consisting of the remaining coils.
Each coil belonging to the first coil group is arranged such that one side portion of each coil faces each pair of magnetic poles of different polarity in the DC magnetic field forming member. In addition, the other side portion of each coil belonging to the first coil group is arranged in the first space where a strong magnetic field is formed by doing so. By arranging each pair of magnetic poles of different polarities in the above-mentioned DC magnetic field forming member to face each other, the member is arranged in the second space where a strong magnetic field is formed, and the second A reproducing needle drive device for an information signal reproducing element, in which each coil belonging to a coil group is integrally provided with a coil of the first coil group.