JPS5834610Y2 - Cantilever device for signal tracking in rotating recording medium playback device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a cantilever device for signal tracking in a rotating recording medium reproducing device, in which lines of magnetic force from a magnetic member disposed opposite to the cantilever pass perpendicularly to the cantilever regardless of the displacement position of the cantilever. It is an object of the present invention to provide a cantilever device for signal tracking which can improve tracking linearity and has good tracking accuracy by making the magnetic surface of the magnetic member arc-shaped.

Figures 1 and 2 were previously filed by the applicant in Japanese Patent Application No. 51-1.
23285 (Japanese Unexamined Patent Publication No. 53-48501) shows a perspective view of a main part of a "signal tracking side force/tilever device for a rotary recording medium reproducing device" and a view taken in the direction of the arrow X.

In the figure, reference numeral 1 denotes a cantilever, whose base side is attached to a holder 3 via a damper 2, and a signal reproducing scanner 5 attached to a video disk 4 is fixed to its tip side.

6 is a permanent magnet piece, which is fixed to the lower side of the holder 3;
It is provided slightly above the force/tilever 1 and extends in the same direction as the cantilever 1, and magnetic lines of force 7 are formed around the force/tilever 1.

As shown in FIG. 2, the magnet piece 6 is magnetized with S and N poles in the thickness direction, and its magnetic pole faces 6a and 6b are both formed in a straight line.

Reference numeral 8 denotes a conductive wire, which is fixed to the top of the force/tilt lever 1 and extends in the axial direction thereof, and lead wires 9a and 9b drawn out from both ends thereof are connected to terminals 10a and 10b on the holder 3. There is.

A lead wire 11 is connected between the scanning element 5 and the terminal 12.

The reproduction section of the apparatus shown in FIG.
This is similar to the reproducing apparatus in the "Video Signal Recording and Reproducing System" proposed in No. 38808 (Japanese Unexamined Patent Publication No. 52-122416).

During playback, the cantilever 1 is moved at a predetermined speed in the radial direction of the video disc 4 (in the direction of arrow E), and when the scanner 5 scans a position on the video disc 4 that is off the main information signal track 13, the scanner 5 The pilot signal is reproduced, and as a result, the error output voltage output from the servo circuit described in Japanese Patent Application No. 51-38808 "Video Signal Recording and Reproducing System" is applied to the terminals 10a and 10b.

As a result, a direct current flows through the conducting wire 8, and a horizontal force indicated by an arrow F acts on the conducting wire according to Fleming's left-hand rule.

Therefore, the cantilever 1 is rotated in the direction of arrow F using the damper 2 as a fulcrum depending on the magnitude and direction of the DC current, and when the scanning element 5 scans a position out of the signal track 13, a tracking control operation is performed. , the scanner 5 faithfully scans a predetermined track 13.

However, according to this device, the magnetic pole face 6 of the magnet piece 6
a and 6b are linear as shown in FIG.
Since it does not pass perpendicularly to the upper conducting wire 8, electromagnetic force is not reliably generated, leading to problems such as poor tracking linearity and decreased tracking accuracy.

The present invention solves the above-mentioned problems, and each embodiment thereof will be described with reference to FIG. 3 and subsequent figures.

FIG. 3 is a diagram showing the relationship between the magnet piece and the force/tilever of the first embodiment of the signal tracking cantilever device used in the rotary recording medium reproducing apparatus according to the present invention.

In the same figure, 14 is a permanent magnet piece that constitutes the main part of the present invention, and the first
Like the device shown in the figure, it is fixed to the lower side of the holder 3, and is provided slightly above the cantilever 1 so as to extend in the same direction as the cantilever 1.

The magnet piece 14 has an S pole and an N pole magnetized in the thickness direction, and the eight magnetic pole surfaces 14a are formed in a straight line, and the N magnetic pole surface 14b is formed in an arc shape and has a concave surface. There is.

The rest of the configuration is the same as that of the device shown in FIG. 1, so a description thereof will be omitted.

According to the first embodiment, as is clear from FIG. 3, the lines of magnetic force 15 from the N magnetic pole face 14b are perpendicular to the conducting wire 8 on the cantilever 1 at any position in the operating direction of the cantilever 1 (direction of arrow F). pass through.

Therefore, no matter where the cantilever 1 is located in the direction of the arrow F, electromagnetic force can be generated reliably and efficiently, the linearity of tracking can be improved, and the tracking accuracy can be improved.

FIG. 4 is a diagram showing the relationship between the magnet piece and the cantilever of the second embodiment of the device of the present invention.

In the figure, reference numeral 16 denotes a magnet piece, the S magnetic pole surface 16a is formed in an arc shape and has a convex surface, and the N magnetic pole surface 16b is formed in an arc shape and has a concave surface.

Other configurations and operations are the same as in the first embodiment, so
The explanation will be omitted.

FIG. 5 is a diagram showing the relationship between the magnet section and the cantilever of the third embodiment of the device of the present invention.

In the figure, 17 is a permanent magnet piece, and both the S magnetic pole surface 17a and the N magnetic pole surface 17b are formed in a linear shape.

18 is a ferromagnetic material, the surface 18a is formed in a straight line and the surface 18b is formed in an arc shape and is a concave surface.
It is fixed to 7.

The magnetic part 19 is constituted by the magnet piece 17 and the ferromagnetic body 18, and the first. As in the second embodiment, it is fixed to the lower side of the holder 3.

In the third embodiment, the surface 18a of the magnetic body 18.

18b is magnetized to the S pole and the N pole, respectively, and the lines of magnetic force 15 from the surface 18b are the first. It is emitted in exactly the same way as in the second embodiment.

In this case, since the magnet piece 17 does not require any force, a commercially available one can be used, and the magnet piece 17 can be small.

Other configurations and principles are the same as in the first embodiment, so
The explanation will be omitted.

In the third embodiment, instead of the ferromagnetic material 18, a material with high magnetic permeability may be used.

Note that the operating range of a cantilever decreases as it approaches the base, so if the radius of curvature of the arc-shaped magnetic pole surface is made smaller as it approaches the base of the cantilever and the magnetic pole surface is brought closer to the force/tilever, the lines of magnetic force can be reduced. The density can become even denser, further improving efficiency.

As mentioned above, the signal tracking force/tilever device applied to the rotary recording medium reproducing device of the present invention consists of a cantilever with an information signal reproducing scanner attached to the tip and supported at the base, and an extension to apply a magnetic field to the cantilever. The magnetic members are arranged to be spaced apart from each other in the track width direction and have an arcuate magnetic surface on at least the surface facing the cantilever, and when the tracking control power is applied, the cantilever is displaced and the signal reproducing scanner is moved in the track width direction. Since the magnetic force lines from the magnetic member are configured to pass perpendicularly to the cantilever regardless of the displacement position of the force/tilever, the electromagnetic force is reliably and efficiently applied regardless of the position of the force/tilever. can be generated, therefore, the linearity of tracking can be improved, the tracking accuracy can be improved,
Furthermore, in the magnetic member, the radius of curvature of the arcuate magnetic surface becomes smaller as it approaches the base of the cantilever, so the magnetic surface can be brought closer to the cantilever, thereby making the density of magnetic lines of force even denser. The efficiency can be further improved.Furthermore, since the magnetic member is made by bonding a permanent magnet piece and a ferromagnetic material or a high permeability material, commercially available permanent magnets can be used, and the magnet It has the advantage of being small and can be constructed at low cost.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the main parts of an example of a signal tracking force/tilever device previously proposed by the present applicant, FIG. 2 is a view taken in the direction of arrow X in FIG. 1, and FIGS. 3 to 5 2A and 2B are views in the direction of arrows when the first to third embodiments of the cantilever device for signal tracking according to the present invention are applied to the device shown in FIG. 1, respectively. 1... Cantilever, 2... Damper, 4... Video disk drive 5... Signal reproducing scanner, 6, 14, 16
゜17...Permanent magnet, 6a, 6b, 14a, 1
4b. 16a, 16b, 17a, 17b...Magnetic pole surface, 7°1
5... Lines of magnetic force, 8... Conductive wire, 13... Main information signal transmission 18... Ferromagnetic material, 19... Magnetic part.

Claims (3)

[Scope of utility model registration request] (1) The base is designed such that the distal end on which the signal reproducing scanner for scanning the recording track of the rotating recording medium on which the information signal is recorded in a spiral or concentric track and reproducing the information signal is movable. A force/tilever supported via a buffer member and spaced apart from each other in the direction in which the cantilever itself or the conductor extends in order to apply a magnetic field to the cantilever itself or a conductor attached to the force/tilever. At least the cantilever itself or a magnetic member having an arcuate magnetic surface on a surface facing the conductor is arranged, and the force/tilever is directly applied by applying the truck blow control power to the cantilever itself or the conductor. The signal reproducing scanner is displaced in the width direction of the track by being displaced using the buffer member as a fulcrum, and the lines of magnetic force from the magnetic member are applied to the force/tilever itself or the conductor regardless of the displacement position of the force/tilever. A cantilever device for signal tracking in a rotating recording medium reproducing device configured to pass vertically. (2) Signal tracking in the rotating recording medium reproducing device according to claim 1, wherein the magnetic member is formed so that the radius of curvature of the arcuate magnetic surface becomes smaller as it approaches the base of the cantilever. Cantilever device for use. (3) The cantilever device for signal tracking in a rotary recording medium reproducing device according to claim 1, wherein the magnetic member is a utility model registration in which the magnetic member is formed by bonding a permanent magnet piece and a ferromagnetic material or a high magnetic permeability material.