JPS5819750A - Pickup element and its production - Google Patents

Abstract

PURPOSE:To form easily an electrode and a stylus with high accuracy, by forming a conical part at the lower end part of a columnar member, forming a plane part on the side surface of the conical part, and then forming an electrode having a prescribed width at the plane part respectively. CONSTITUTION:First a columnar member 21 of diamond, sapphire, etc. is polished at its lower end part to obtain a conical part 22, and a plane part 23 is formed on the side surface of the part 22. Then an electrically conductive film 24 of titanium, etc. is formed on the surface of the member 21 by a vapor deposition process, etc. An electrode part 25 having a width W of about 1mu is left at the center of the part 23, and both sides of the part 25 are removed by a laser process, etc. Then the film 24 at the part 22 is eliminated by a rotary polishing process excepting the part 23. Thus the part 22 forms a stylus area, and a shank part is secured at the upper part of the stylus area to be supported by a cantilever, etc. The film 24 at the shank part functions as a lead wire.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pickup element used in high density recording disc players such as video disc players and digital audio disc players.

In recent years, a spiral cooling disk has been developed as a recording medium.

Signal recording methods for such high-density recording disks include an optical method in which bits (light transmission holes) are formed using a laser beam along the signal recording line, and an optical method in which bits (small holes) are formed along the signal recording line. There is a method called a capacitance method that provides a capacitance.

Among these methods, in order to reproduce high-density recording disks using the capacitance method, there is a method that detects sequential changes in capacitance-fit as signal information by sliding a pickup element having electrodes along the signal recording line. Be taken.

As shown in Fig. 1, this pickup element has a shank part (not shown) formed with a metal film on a part of the surface of a needle part (1) made of diamond, etc., to constitute a needle-side electrode (2). There is. This electrode (2) is then deposited by vapor deposition or sputtering. In Fig. 1, (3) is the information bit of the video disc, (4) is the pilot bit, and the width W of the electrode (2) of the pickup element is 1 micron (approximately 1 micron).

The manufacturing of such a conventional pickup element involves polishing the lower end of a cylindrical material (Iυ to form an electrode surface 02, as shown in Fig. 1 and Fig. 5). A metal film (13) is formed on the surface of the material (1), and then,
The lower end of the cylindrical material (11) is formed into a pyramid shape through a plurality of polishing steps, and the metal film (13) is left on the electrode surface (12) of the pyramid-shaped part, that is, the needle part (ll). 2).

According to this method, it requires a high degree of skill to finish the width W of the wire +fif2+ to about 1 micron, and it requires only one needle.
Multiple polishing steps are required to form Xl((]'), and the processing time is also long.
It is easy to peel off, and it is easy to make mistakes such as under-polishing or over-polishing, and the edges are also easy to chip, so it is constant 1-1]
It was difficult to obtain the electrode (2) of NV).

Since the needle part (1) of this conventional pickup element is pyramid-shaped, during use, fine dust carried by the high-speed airflow generated by the high-speed rotating disk is likely to collide with the needle part (1). 1) is prone to chipping, and since both edges of the electrode (2) are polished together with the surface adjacent to the electrode surface 02, the bonding force with the material (11) is weakened and it is easy to peel off. Moreover, since this part is located on the ridgeline of the needle part (1), it is easily subjected to external force, and therefore, the 'i:,\ pole (2) is easily damaged.

The present invention was made in view of the above points, and an object of the present invention is to provide a pickup element in which electrodes and needle parts can be easily formed, can be manufactured accurately and quickly, and is not easily damaged. That is.

The 111th invention includes a conical part formed at the lower end of the columnar member, a flat part formed on the side surface of the conical part, and a predetermined width approximately at the center of the flat part. The device is characterized by comprising an electrode extending in the length direction of the member.

In addition, in the manufacturing method of the pickup element, 2-Nori, a columnar shape is formed at the bottom of the member: 'A conical part is formed in the W part, and this circular ζf-shaped part is (Iili'
A conductive film is formed on the surface of the columnar member indicated in -, and the conductive film on the 51'-plane part is heated to approximately medium heat on the 1111 part with a predetermined width. Li, Ii P means removing the electrode portion along the length of the member, removing the electrode portion on both sides, and removing the conductive film on the conical portion other than the flat portion.

Further, the third invention is also a method for manufacturing the above-mentioned pickup element, in which a flat portion inclined by degrees Celsius with respect to the axial direction of the columnar member is formed at the lower end of the columnar member, and the surface of the columnar member is conductive. forming a film, and forming a conductive film on the planar portion with a predetermined width approximately in the center of the planar portion;
Remove the image-side portion of the columnar member, leaving the electrode h7 portion that has slipped in the length direction, and attach a circle to the lower end of the columnar member, leaving part of the flat portion on both sides of the electrode portion. fi'[I
It is characterized by forming a ;-shaped portion.

Next, η(
The RQ will be explained in detail based on the 6th figure of the spear to the 11th figure of the tusk.

(1) A conical part (221) is formed at the lower end of the cylindrical member 0υ made of diamond or sapphire by rotary polishing (Fig. 6 to Fig. 7) (2) Next, - A flat part (shaped part) is formed on the side surface of the conical part (shaped part) by polishing. (From Figures 1 and 7 to Figure 8) (3) Next, a conductive film Qa of titanium or the like is formed on the surface of the cylindrical member eυ by vapor deposition or sputtering.

(Fig. 8 to Fig. 1 and 9) Next, of the conductive film C 1) of the above-mentioned flat part (C), the flat TI5 part e; ◇
A part of the electrode along the length of the columnar member (21) with a width W of about 1 micron (within width W) is left at the approximate center of the columnar member (21), and both sides of the electrode are removed by laser processing or electron beam processing. (Fig. -9 to Fig. 10) (5) Next, the conical part other than the flat part (23) (
Conductivity Ill (24+ is removed by rotary polishing. (Figure eJ-10 to Figure 11) If it is not possible to accurately obtain the diameter ν in the step (1) above, a step of polishing the lower end surface of the cylindrical member Cυ can be performed after the step (5) above to accurately obtain the value of the diameter ■. If possible, at this time, the conductive coating (24) on the lower end surface of the cylindrical member (21) can also be removed at the same time.

The pickup element manufactured in this way was 1.11
As shown in the figure, there is a conical part (221) at the lower end, a flat part (23) on the side surface of this conical part (221, and a flat part (t23)) approximately 1 micron in the center. Electrodes (c) along the length of the cylindrical member 01) with a width W
have.

The conical part @ is a needle part, the upper part of this needle part is a shank part, this shank part is supported by a cantilever, etc., and the conductive film 24) of this shank part functions as a lead wire.

The cylindrical member Cυ may be made of a metal such as titanium and diamond or sapphire bonded to the lower end thereof.

Next, a method of manufacturing the pick-up element 2 of the present invention will be specifically explained based on Figures 12 to 16.

(1) First, at the lower end of a cylindrical member (21) made of diamond or sapphire, a plane part (2 grooves) which is inclined with respect to the axial direction of the cylindrical member eυ is formed by polishing. (From Figure J13 to Figure 14) (2) Next, a conductive film (24) of titanium or the like is formed on the surface of the cylindrical member (2I) by vapor deposition or stamping. (From Figure J13 to Figure 14) (3) Next, , Of the conductive film (24) on the 0th floor of the flat part, an electrode C portion slid in the length direction of the cylindrical member 0υ with a width of about 1 micron (T) approximately on the middle of the 0th floor of the flat part. Laser machining the both sides of the tooth while leaving the tusk 15
(4) Next, at the lower end of the cylindrical member (21), the conical part (2 parts) was polished by rotation, leaving a part of the flat part (23) on both sides of the electrode (29 part). Form.

(Figures 15 to 16) In addition, the conductive coating (24) on the lower end surface of the cylindrical member (21)
The step of removing the diameter (6) of the lower end surface of the cylindrical member (21) is carried out after the step (4) above, if necessary.
) can also be calculated accurately.

The pickup element manufactured in this way was 1.16
As shown in the figure, it has the same structure as the pickup element manufactured by the manufacturing method 1.1.

In each of the inventions described above, a cylindrical member is used as the columnar member, but the present invention is not limited to this, and a prismatic member may also be used.

As mentioned above, since the pickup element of the present invention has a substantially conical needle, it is difficult for minute dust etc. carried by the high-speed airflow generated by the disk rotating at high speed to collide with it during use. , the needle part is less likely to chip,
In addition, since the line parts on both sides of the electrode are separated from the ridgeline of the boundary between the flat part and the conical part, the <<'I+Y pole is less likely to be damaged by external force, and in addition, compared to the conventional pyramid-shaped one, In this case, if the diameter of the lower end surface of the needle portion is made the same, the area of the lower end surface will be increased, so that the wear resistance will be improved and the life will be extended.

In manufacturing, in both the manufacturing method of spear 1 and the manufacturing method of fang 2, the curve of the electrode is not polished to a predetermined width by multiple times, but is finished by a laser or the like, which improves accuracy. The electrodes do not peel off, and the needle portion only needs to be formed in one step of rotary polishing, so the processing time is shortened and the needle portion is not chipped.

[Brief explanation of drawings]

Blade・Figure 1 is a perspective view showing a conventional pickup element, 2.
Figures 2 to 5 are perspective views showing each step of the manufacturing method, and Figures 6 to 5 are perspective views showing each step of the manufacturing method. FIG. 11 is a perspective view showing each step of the method for manufacturing the pickup element spear 1 of the present invention, and FIGS. 1712 to 16 are perspective views showing each step of the manufacturing method of the pickup element spear 2 of the present invention. (21)・Cylindrical member, (22)・φ conical part, C(
To) fist/flat part, (24)... conductive film, (251...
·electrode.

Claims (3)

[Claims] (1) A conical part formed at the lower end of the columnar member,
A pickup comprising a flat portion formed on a side surface of the conical portion, and an electrode formed approximately at the center of the flat portion with a predetermined width along the length direction of the columnar member. element. (2) A conical part is formed at the lower end of the columnar member, a flat part is formed on the side surface of the conical part, a conductive film is formed on the surface of the columnar member, and the conductive film on the flat part includes: removing the electrode portion along the length of the columnar member with a predetermined width approximately at the center of the planar portion, and removing the portions on both sides thereof;
A method of manufacturing a pickup element, characterized in that the conductive film on the conical portion other than the flat portion is removed. (3) Forming a plane part at the lower end of the columnar member that is inclined with respect to the axial direction of the columnar member, forming a conductive film on the surface of the columnar member, Remove the electrode portion along the length direction of the columnar member with a predetermined width from the middle shaft, and remove both sides of the electrode portion, and add a portion of the flat portion to the lower end of the columnar member on both sides of the electrode portion. A method for manufacturing a pickup element, characterized in that a conical portion is formed by leaving a conical portion.