JPS5812654B2 - Record stocking needle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel record stylus suitable for reproducing high-density information recording media such as video records.

October 15, 1974 Patented by Clemens (Jo)
nK. Clemens) U.S. Patent No. 3,842,194
The patent specification discloses various capacitive video playback devices, and in one of the Clemens systems, information representing recorded images and sounds is stored on a relatively fine (for example, wide) disc-shaped record surface. The record substrate is coated with a conductive material and further coated with a dielectric layer.

During playback, when the record is rotated by a support turntable, a pickup storage needle with a thin (for example, about 0.2 μm thick) conductive electrode is engaged in the groove, and the electrode of the storage needle and the conductive coating are connected to each other. The device detects the change in capacitance between the two and plays back the pre-recorded information.

In the above-mentioned type of device, the groove of the record used is relatively thin, and the conditions for engagement between the pickup needle and the groove are severe.
The tip of the storage needle becomes extremely small.

In general, a storage needle point has a point, a substantially flat V-shaped back surface separated from the point, a bottom surface extending from the bottom of the back surface, and a pair of side surfaces extending from the sides of the back surface and mating with the point. defined by.

The intersection lines of the back and side surfaces with the bottom surface form, for example, a triangular bottom mark.

For example, the angle between both sides is 42°, and the length of the base is approximately 2μ.
, the height of the triangular bottom mark is about 4μ, and the angle between the tip and the back surface is about 40°.

The Clemens patent described above describes two types of needle storage structures.

That is, (1) a symmetrical structure in which a conductive storage needle electrode is sandwiched between dielectric support materials extending symmetrically in front and behind it (FIG. 1); and (2) on the back surface of the dielectric support of the storage needle electrode. It is an asymmetric structure (Fig. 5) with a dielectric coating on both sides.

It has been proven that asymmetrical accumulator electrodes are easier to fabricate if the entire back surface is coated with conductive material, whereas V-shaped accumulator electrodes widen as the accumulator wears, and therefore the electrode Pseudo capacitance between the groove and the conductive film of the adjacent groove becomes significant, causing noise to be included in the reproduced signal.

Therefore, if the storage electrode becomes wider than the width of the groove (for example, 3.5μ), it is desirable to replace the storage needle.

Furthermore, when the two types of accumulators described in the Clemens patent become wider with use, they may simultaneously cover several grooves during playback, resulting in accumulator mistracking and composite signal distortion.

The keel-type pointed pickup accumulator described here avoids the above-mentioned problems that occur when reproducing prerecorded signals due to the relative movement between the accumulator and the record.

The pick-up stylus has a dielectric support element having a pointed head defined by a pointed end and a generally flat rear surface spaced from the pointed end.

The terminal end of the back surface is formed by a base, a pair of side edges extending substantially perpendicularly from both ends of the base, and a pair of sides extending laterally from the ends of the sides.

The maximum distance between both sides is smaller than the predetermined groove width.

Further, the point has a bottom surface extending from the base to the point.

Further, a pair of side surfaces extend substantially parallel to each other from both sides toward the tip at a distance smaller than the width of the groove, a pair of surfaces extend from the horizontally extending sides toward the tip, and furthermore, a pair of side surfaces extend in parallel to each other at a distance smaller than the width of the groove. The surfaces extending from the ends of the sides meet at a point.

When the accumulator needle is inserted into the record groove during playback, the base crosses the groove and contacts the groove bottom at the meeting point, and the parallel sides follow the direction of the groove, and the record moves from the tip to the bottom. It is supposed to move.

Further, the dimensions of the storage needle are such that when the storage needle is inserted into the groove, the horizontally extending surface is separated from the record surface.

To produce this keel-shaped pointed accumulator, the tapered point of the support element is fitted into the polishing groove.

This groove has a bottom surface, substantially parallel side surfaces having an interval smaller than the predetermined width, and a top surface extending from the side surfaces.

The operation is carried out by holding the tapered support element in a fixed direction with respect to the polishing groove while performing a relative movement therebetween along a straight line in a plane approximately perpendicular to the V-shaped back surface.

The sides of the polishing groove form the sides of the longitudinally restricted end of the tapered support element, and the top surface forms a shoulder connecting this restricted end to the remainder of the tapered support element. be done.

When the distal end reaches a predetermined height, the relative movement is stopped.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an example of a variable capacity type video record playback system 20 shown in the above-mentioned Clemens patent. The turntable 22 rotates at a speed (for example, 450 rpm).

The turntable 22 centers and supports a video record 26 having recorded information representing images and sounds in the spiral grooves on its surface.

The spiral grooves of the video record 26 are relatively close together (e.g., groove pitch 3.5μ) to ensure proper playback time.
.

As mentioned above, the video record 26 has a conductive coating on its substrate and a dielectric coating thereon.

The needle storage support arm 28 holds a storage needle 30 that engages with the vortex groove at its free end, and is supported by a transfer frame 32 at the other end.

The pivot device of the needle storage support arm 28 is made by B.K.
or) as disclosed in US Pat. No. 3,917,903.

During playback, the transfer frame 32 traverses the video record 26 in its radial direction at a speed suitably synchronized with its rotation, so that the accumulator 30 can maintain a predetermined constant posture within the groove of the video record.

The moving device of this transfer frame is a stave (F.R.Stav).
e) etc. may be of the type disclosed in US Pat. No. 3,870,835.

As mentioned above, the storage needle 30 is relatively thin (for example, with a thickness of 0
．． The pickup circuit 34 detects the change in capacitance between the storage electrode and the conductive coating of the video record during playback.

The output of the pickup circuit 34 is converted by a signal processing circuit 36 into a form suitable for use in a television receiver.

This pickup circuit 34 is designed by Kawamoto (H.Kawamoto).
The signal processing circuit 36 is of the type described in U.S. Patent Application No. 743144 of U.S. Pat.
3,969,757.

FIG. 2 shows a conventional storage needle having a V-shaped point.

The V-point accumulator 38 comprises a dielectric support element 40 having a V-point 42 .

The ends of the V-shaped point 42 include a point 44, a substantially flat back surface 46 remote from the point, a bottom surface 48 extending from a base 50 of the back surface, and extending from sides 56 and 58 of the back surface. It is defined by a pair of side surfaces 52 and 54 that meet at the apex.

The intersection of the back surface 46, the side surfaces 52 and 54, and the bottom surface 48 defines, for example, a triangular accumulator bottom trace.

The entire surface of the back surface 46 of the needle storage support element 40 is coated with a conductive material to form an electrode 60.

3, 4 and 5 show the life course of the V-shaped point storage needle 38 as it travels along the groove on the surface of the video record 72.

Video record 72 has a conductive coating 76 on a substrate 78 and a dielectric coating 74 thereon.

When the storage needle 38 is worn to the shape shown in FIG. 4, the width of the storage needle electrode 60 becomes equal to the distance between adjacent grooves (for example, 3.5μ).

As the width of the storage needle electrode 60 increases, interference in the pickup output increases, making it necessary to replace the storage needle.

If the storage needle 38 is left to wear out to the state shown in FIG. 5, the storage needle will cover several grooves and cause derailment (mistracking).

This problem is solved by the bone-shaped point storage needle according to the present invention.

6 and 7 are perspective views of the keel-shaped pointed storage needle 80, and FIGS. 8, 10, and 11 are front, side, and bottom views of modifications of the bone-shaped pointed storage needle 80. be.

FIG. 9 shows a worn state of the keel-shaped point storage needle 80 shown in FIGS. 8, 10, and 11.

As shown in the figures, the bone-shaped point storage needle 80 has a dielectric support element 82 that includes a base body 84 having sloped surfaces 86 and 88 and a narrow anteroposterior edge 90. , shoulders 92 and 94 joining the ramp to the edge 90.

The narrow edge 90 has a point 96, a substantially flat back surface 98 spaced from the point, a pair of generally parallel side surfaces 100 and 102 extending from the sides of the back surface, and a pair of generally parallel sides 100 and 102 extending from the bottom of the back surface. It is defined by a bottom surface 104 and a pair of additional surfaces 106 and 108 extending from the tip and intersecting the bottom surface and the sides.

The intersection lines of the back, side and additional surfaces with the bottom surface define a pentagonal accumulator bottom trace in this embodiment.

This keel-shaped point storage needle has a structure in which the apex of the pentagonal bottom mark is on the tip 96.

In the embodiment of FIGS. 6 and 7, shoulders 92 and 94
are parallel to the bottom surface 104 of the narrow edge 90, but may be inclined outwardly relative to the bottom surface 104, as shown in FIGS. 8-11.

8 and 9 show that a keel-shaped point storage needle 80 with inclined shoulders 92 and 94 is attached to a predetermined width of the surface of a video record 110 having a conductive coating 112 and a dielectric adhesive layer 114 thereon. This shows the life process when moving along the groove.

It is understood that this storage needle has a large amount of wear before it becomes unusable, so its lifespan is extended by that much.However, as the storage needle wears out, its electrode width does not widen, and both ends of the electrode are V-shaped. The performance of the stylus is significantly improved because it is far away from the conductive coating of the adjacent groove of the video record compared to the electrodes of .

An example of the shape and dimensions of the keel-shaped point storage needle 80 is as follows.

Angle between slopes 86 and 88: 42°, narrow edge 9
Height of 0...5μ, interval between the nearly parallel side surfaces of the narrow edge...3μ, length of the narrow edge...8μ, angle between the tip 96 and the bottom surface 104...35 It is ゜.

The life of the keel-shaped pointed needle storage having the above dimensions and shape is approximately twice that of the V-shaped pointed needle storage, and the increase in signal-to-noise ratio (SN ratio) is about 3 dB (on average).

The keel-shaped pointed storage needle not only has excellent performance and service life, but also can be manufactured relatively easily by modifying the ■-shaped pointed storage needle (for example, as shown in FIG. 2).

As shown in FIG. 12, the keel-shaped pointed accumulator is formed by running a V-shaped pointed accumulator 116 on a polishing disk 118 having deep, coarsely pitched grooves 120.

As shown in FIG. 13, the top surface 122 of the polishing disk 118
and 124 polish shoulders 92 and 94, polishing groove 1
side 1 in which walls 126 and 128 of 20 are substantially parallel;
Polish 00 and 102.

The polishing groove 120 can be made deeper than the height of the keel-shaped end 90 and the bottom mark of the storage needle can be polished later, but as shown in FIG. It can also be placed at a location where the material is being polished.

The polishing disk 118 shown in FIGS. 12 and 13 is the sixth
A keel-shaped pointed storage needle having the shape shown in the figure and FIG. 7 is produced.

As shown by the broken lines in FIGS. 12 and 13, by appropriately deforming this polishing disk, the polishing disks shown in FIGS.
It is also possible to make a keel-shaped point storage needle having the shape shown in Figure 1.

Next, a method of manufacturing the polishing disk 118 will be explained.

A sufficiently flat and smooth copper clad plate is coated with a thick film (e.g. a few microns) of photoresist, which is then exposed to a highly energetic beam (e.g. electron beam or light beam) of a predetermined width (e.g. 3.5 microns) with coarsely pitched vortices. After exposing along the line trajectory and developing the exposed photoresist coated substrate,
The exposed areas of the photoresist are removed to form coarse spiral grooves on the substrate.

From now on, a metal press mold will be manufactured using electroless plating, etc.
A plastic disc is pressed using this metal press mold.

This plastic disc can also be made from the same material as a video record.

An abrasive material such as Sio2 is deposited thereon to form an abrasive layer 132 as shown in FIGS. 12 and 13.

Keel point accumulators according to embodiments of the invention have been successfully made from diamond or sapphire support elements.

The above keel type point polishing method is not only used for factory production, but also for home use,
This can be done at a retail store or repair shop, or it can be used in factories to recycle worn out needles.

Although the present invention has been described with reference to a capacitive pickup accumulator, the principles are equally applicable to, for example, a pressure pickup accumulator.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a video record reproducing apparatus for reproducing a signal prerecorded in a record groove of a predetermined width using a keel-type pointed storage needle constructed according to the present invention. FIG. 2 is a perspective view of a conventional storage needle having a V-shaped point. FIGS. 3, 4, and 5 are diagrams showing the process of the V-shaped point storage needle shown in FIG. 2 until it reaches the end of its life as it moves through the record groove. FIGS. 6 and 7 are perspective views of a keel-shaped pointed needle storage device used in the device of FIG. 1. FIG. FIGS. 8 and 9 are diagrams showing the process by which one modification of the keel-shaped point storage needle shown in FIGS. 6 and 7 reaches the end of its life while traveling in a record groove. FIGS. 10 and 11 are a side view and a bottom view of the modified keel type pointed needle storage shown in FIGS. 8 and 9. FIG. FIGS. 12 and 13 are views showing a portion of a polishing disk suitable for forming the keel-shaped pointed needle accumulator shown in FIGS. 6 and 7. FIG. 82... Dielectric support element, 92, 94...
...Pair cross section, 96...Tip, 98...
... Rear, 100, 102... Side, 104.
... Bottom surface, 106, 108 ... Surface extending from the edge of the side surface, 114, 117 ... Groove.

Claims (1)

[Claims] 1. In order to reproduce the pre-recorded signals by relative movement with the record in a playback device that includes a turntable that rotates a disc-shaped record on which a signal is pre-recorded at the bottom of a spiral groove of a predetermined width provided on the surface. a point, a base, and a pair of laterals extending substantially perpendicularly from both ends of the base with a maximum distance equal to or less than the predetermined vortex groove width on the side remote from the point; a dielectric having a pointed head defined by a pair of sides extending laterally from the ends of the sides remote from the base; and a substantially flat back surface having a distal end formed by the sides. The point further includes a support element, the point further comprising a bottom surface extending from the base and terminating in the point, and a bottom surface extending from the side toward the point substantially parallel to each other and spaced apart by a width less than or equal to the vortex groove width. a pair of extending side surfaces, a pair of surfaces extending from the horizontally extending sides toward the tip, and a surface extending from the end of the parallel side surfaces away from the back surface and meeting at the tip. At the meeting point with the vortex groove during playback, the bottom side crosses the groove and the bottom surface contacts the bottom of the groove, and at the same time, the parallel side surfaces move along the direction of the groove so that the record is The tape moves from the tip toward the bottom, and is dimensioned and shaped so that when the tip is fitted into the groove, the surface facing the tip is separated from the surface of the record. A storage needle for records.