JPS5813449Y2 - regenerated needle - Google Patents

Description

[Detailed description of the invention] The present invention relates to a playback stylus that plays back a disc in which information signals are recorded in a spiral or concentric manner as a change in geometrical shape, and particularly relates to a disc scanning surface of the main body of the playback stylus and this scanning surface. The apex corner formed by the ridge line formed by a pair of side surfaces adjacent to the surface and the ridge line formed by the other two pairs of side surfaces has a rounded shape at least within the range that does not touch the electrode. Therefore, it is an object of the present invention to provide a disc playback needle configured to eliminate damage to the disc during playback and to smoothly transport the playback needle in the radial direction of the disc.

The present applicant previously proposed in Japanese Patent Application No. 51-38809 ``Video Signal Recording and Reproducing System,'' etc., in which a video disk is made flat without a guide groove, and trunking control is performed adjacent to a spiral information signal recording trunk. A system in which the reproducing needle is regenerated during relative scanning by the reproducing needle, and while trunking is controlled according to the pilot signal, the information trunk is accurately scanned to detect and reproduce the information signal. proposed.

In this system, since a grooveless disc is used, the playback needle can be freely moved upward in the radial direction of the disc, thereby enabling random access of signals and link play at double speed.

As a regenerated needle applicable to the above method, the present applicant previously proposed a regenerated needle 1 shown in FIG. 1 in Japanese Patent Application No. 52-34106 ``Information Regeneration Needle and Manufacturing Method Therefor''.

This regenerated needle 1 has a needle main body 2, an electrode surface 3 on the back side, a polished surface 4.5 and 6,1 symmetrically formed on the tip side, and a substantially diamond-shaped disk scanning surface at the tip end. It forms 8.

Both the polishing surface and the disk scanning surface are flat mirror surfaces, and the disk scanning surface 8 forms the outline of the disk scanning surface 8.
and each ridgeline portion 2a where the adjacent surfaces 2 to 7 intersect
-7a both have a sharp shape.

Further, the intersection between the disk scanning surface 8 and the pair of polished surfaces 4 and 6 forms a sharp wedge-shaped portion 9, and the intersection between the disk scanning surface 8 and another pair of polished surfaces 5 and 1 is also sharp. A wedge-shaped portion 10 is formed.

The regenerated needle 1 has a cantilever 1 as shown in FIG.
The disc scanning surface 8 relatively scans an information trunk 13 of a grooveless video disc 12 rotating at high speed in the direction of arrow A.

At this time, the information signal is detected and reproduced as a change in capacitance by the electrode on the back side.

At this time, the playback needle 1 is in contact with the grooveless video disc 12, as shown in an enlarged view in FIG.
is slightly deformed due to the applied load and the unevenness of the disk surface including the signal.

Here, since the regenerating needle 1 has sharp ridgeline portions 2a to 7a and wedge-shaped portions 9 and 10, the regenerating needle 1 is transferred at a relatively high speed in the disk radial direction indicated by the arrow B by the transfer mechanism groove. In particular, the wedge-shaped portion 9 or 10 often bites into the disk surface 12a.

When this biting phenomenon occurs, torsional stress is generated in the cantilever 11 due to the resistance of the needle tip, and a rotational force in the direction shown by arrow C acts on the regenerated needle 1 as a repulsive force of this torsional stress, causing the biting to occur further. As a result, the smooth movement described above becomes impossible, and random access etc. in the reproduction method cannot be performed smoothly.

Furthermore, due to the biting, a moderate amount of stress is concentrated on the biting part, damaging the disk surface and causing the playback needle to break.

Furthermore, scratches on the disk surface and chips in the playback stylus are caused by debris, resulting in serious problems such as failure to perform normal re-drinking in the event of drop-out.

The present invention solves the above problems, and one embodiment thereof will be described below with reference to the drawings.

FIG. 4 is a perspective view showing the vicinity of the needle tip of one embodiment of the disc reproducing needle according to the present invention, and FIG. 5 is a diagram showing the state in which the reproducing needle of FIG. 4 is attached to a video disc.

In both figures, the same components as those shown in FIGS. 1 and 3 are given the same reference numerals.

In the regeneration needle 14 shown in FIG. 4, the ridgeline 16 between the disk scanning surface 15 and the polishing surface 4, and the ridgeline 17 between the disk scanning surface 15 and the polishing surface 6 are both rounded by the contour of the circumferential side of the cylinder. It is formed as a curved surface.

The ridgeline portion 16 begins to become rounded near the introduction side point a, and as it moves toward the side point C, an arrow S indicates a curved surface.
1. S2. As shown in S3, the curved surface gradually becomes wider,
The ridgeline portion 17 begins to become rounded near the back side point C, and as it moves toward the side side point C, arrows S42 and S5
As shown by js6, the curved surface gradually becomes wider.

The intersection of the pair of curved edge portions 16 and 17 is formed as a curved portion 18 where the wedge-shaped portion 9 disappears.

The radius of the curved ridgeline portions 16 and 17 is 2 to 4μ.
It is m.

Note that the ridgeline portion 19 between the disk scanning surface 15 and the polishing surface 5,
And the ridgeline portion 20 between the disk scanning surface 15 and the polishing surface 7 is
Each of them is formed into a curved shape similar to the above-mentioned ridgeline portions 16 and 17,
At the intersection of each of the ridgeline parts 19 and 20, the wedge-shaped part 10 disappears and a curved part 21 is formed.

As a result, in the disk scanning surface 15 of the reproducing needle 14, all the ridgeline portions that become the polished side surface on the transfer direction side become curved ridgeline portions 16, 17, 19, 20, and a pair of wedge-shaped portions in the transfer direction. 9 and 10 disappear and that part becomes the curved surface part 18
, 21.

Therefore, the disk radial direction of the regeneration needle 14 (direction of arrow B)
When the disk is transferred to the disk, the phenomenon in which the tip of the playback needle bites into the disk surface will no longer occur.

As a result, the playback stylus 14 is smoothly transferred in the radial direction of the disk, and the random access and trick play described above are performed without any trouble, and no damage to the disk surface or loss of the playback stylus occurs.

Further, the disk scanning surface 15 has a relatively large area, with an electrode width W of 2 μm, a length t of about 15 μm, and @W2 of about 10 μm.

Therefore, wear of the disk scanning surface 15 due to the playback operation is difficult to occur, and almost no progress of wear on the surface 15 was observed experimentally, and the curved ridgeline portion 1
6, 17, 19, and 20 will never disappear.

Therefore, the above-mentioned smooth regenerated needle transfer operation can be performed for a considerably long time (the life of the regenerated needle).

Next, a method for manufacturing the regenerated needle 14 is shown in FIGS. 6 to 8.
To explain with reference to the figures, in each figure, the same components as those shown in FIGS. 1 to 5 are denoted by the same reference numerals.

FIG. 6 shows a recycled needle in the middle of the manufacturing process.

This unfinished recycled needle 25 is made by rubbing the tip of the rod-shaped needle material using a tin-lead alloy lamp or plastic clamp and a diamond compound with a diameter of 1/4 μm to form polished surfaces 4, 5, 6, and 7. The structure is such that the back surface is the electrode surface 3.

The apex 26 where each polishing surface 4°5.6.7 intersects has a sharp shape with no defects.

When processing the tip of the unfinished recycled needle 25, the unfinished recycled needle 25 is accurately positioned and fixed to the cantilever 28 with an adhesive 27, as shown in FIG.

The cantilever elastic support part 29 is a cartridge outer part (
(not shown).

In this state, the cantilever 28 is fixed to a transfer mechanism (not shown) of a polishing machine, and the top of the unfinished recycled needle 25 is polished.

In FIG. 7, the rotary table 30 of the polishing machine has a shaft 30a.
It rotates at high speed in the direction of the arrow with the polishing disk 31 mounted and fixed on the top surface.

As shown in FIG. 8, the polishing disk 31 is formed with a spiral groove 32 having a substantially dish-shaped cross section.

On the surface of the groove 32, an abrasive layer 33 is formed by coating several hundred OA of a high hardness material, such as 5i02, by vapor deposition or sputtering.

Further, the spiral groove 32 has a width W3 of the flat bottom portion 34 of 6
~8 μm, and the curved surface portions 35 and 360 radius on both sides are approximately 2 ~
4 .mu.m, and the pinch P is formed to be about 20 .mu.m, leaving a land portion 31 with a width of 5 to 10 .mu.m.

Further, the transfer mechanism (not shown) moves in the direction of arrow E in synchronization with the rotation of the rotary table 300.

As a result, the polishing machine is started, and the unfinished regenerated needle 25 is
By attaching the top of the recycle needle 25 to the spiral groove 32, the recycle needle 25 relatively scans the spiral groove 32, and the abrasive layer 33 in the groove polishes the top 26 of the unfinished recycle needle 250. be done.

This polishing process is carried out to the position shown by the line X--X in FIGS. 6 and 8, that is, to the position where both side surfaces of the unfinished regenerated needle 25 abut against the curved surfaces 35 and 36 of the groove 32.

Through this processing, a regenerated needle 14 shown in FIG. 4 whose needle tip has a shape in which the cross-sectional shape of the groove 32 is transferred is obtained in a state fixed to the cantilever 28.

Note that grooves having the same shape as the grooves 32 of the polishing disk 31 are cut on the lacquer disk by a mechanical canting technique.

If a record duplication technique is used using this as a master, the abrasive disc 31 can be easily reproduced and mass-produced, and even if different abrasive discs 31 are used, recycled needles of the same quality with no variation in shape can be manufactured.

As mentioned above, according to the reproducing needle according to the present invention, the scanning surface of the reproducing needle main body faces the information recording disk and scans the same;
The apex corner is formed by a ridgeline formed by a pair of side surfaces adjacent to this scanning surface and a ridgeline formed by another pair of side surfaces. It has the following features.

- The playback stylus can be moved smoothly in the radial direction of the disc at high speed while keeping it in contact with the disc surface, and the characteristics of the grooveless video disc can be fully utilized.

(2) Since the digging phenomenon does not occur during the above-mentioned movement, damage to the disk surface and loss of the playback needle can be avoided.

(2) Since the above-mentioned biting phenomenon does not occur, unnecessary torsional vibration is not generated in the cantilever during reproduction, and tracking characteristics can be improved.

(2) Since the roundness provided at the apex corner is within a range that does not touch the electrode, the effective width of the electrode does not change even if the roundness is formed, and reproduction can be performed satisfactorily.

[Brief explanation of drawings]

Figure 1 is a perspective view of an example of a conventional regenerated needle as seen from the needle tip;
Fig. 2 is a diagram showing the disk reproducing state of the reproducing needle in Fig. 1;
FIG. 3 is a diagram showing the state in which the reproducing needle shown in FIG. 1 is attached to the disk surface, and FIG. 4 is an enlarged view of the needle tip portion of an embodiment of the disc reproducing needle according to the present invention as seen from the needle tip surface. FIG. 5 is a perspective view showing the state in which the regeneration needle of FIG. 4 is attached to the disk surface;
6 is a perspective view showing the unfinished recycled needle at a processing stage before the recycled needle in FIG. 4; FIG. 1 is a view showing the tip of the unfinished recycled needle in FIG. 6 being polished; Figure 8 shows Vat in Figure 7.
It is an enlarged sectional view along the -■ line. 12...Video disc, 12a...
Disk surface, 13...Information trunk, 14...
... Regeneration needle, 15 ... Tisf scanning surface, 16
, 17 , 19 , 20 ...... curved ridge line part,
18, 21...Curved surface part, 25...Unfinished recycled needle, 26...Top part, 31...Abrasive disc, 32... Spiral groove, 33...
Abrasive layer, 34...Flat bottom, 35, 36...
...Curved surface part.

Claims (1)

[Scope of utility model registration request] The above-mentioned information recording device provided at the tip of a playback needle that plays back the above-mentioned information signal by relatively scanning the recording trunk of an information recording disk in which the information signal is recorded in a spiral or concentric shape as a change in geometrical shape. A scanning surface that slides into at least one trunk of the disc, an electrode forming surface that extends from the scanning surface in connection with this, and a length of the connecting portion between the scanning surface and the electrode forming surface at least near the tip. a regenerating needle main body having a pair of side surfaces for regulating the length of the needle, and another pair of side surfaces connected at an angle to the pair of side surfaces; an electrode that reproduces the information signal as an easy change according to a change in the geometrical shape; and a ridgeline formed by a pair of side surfaces of the regenerated needle, the apex corner being rounded at least within a range that does not touch the electrode.