JPS6338449Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an improvement in the pickup section of a capacitive disc player for audio or video.

2. Description of the Related Art Conventionally, a pickup section for a disk player as shown in FIG. 1 has been known. In FIG. 1, 1 is a pick-up needle, 2 is a fly lead connected to the pick-up needle 1, and 3 is a cantilever, at the base of which a permanent magnet 15 for electromagnetic driving is attached. Reference numeral 4 represents a tracking correction electromagnet for performing tracking correction, and 5 represents a jitter direction correction electromagnet for performing correction in the jitter direction. 6 is a rod-shaped rubber elastic body that supports the cantilever 3. What Figure 1 shows is that
A diamond pick-up needle 1 with an electrode film 7 (shown in Figure 2) is attached to a straight cantilever 3, and a fly lead 2 guides changes in capacitance due to the pick-up signal to a signal detection circuit consisting of a resonator and a UHF oscillator. It is something. The pick-up needle 1 makes plane contact with the disk, and performs tracking and jitter correction in the radial direction of the disk and in the tangential direction of the signal track on the disk via the tracking correction electromagnet 4 and the jitter direction correction electromagnet 5. multiply. The cantilever 3 is supported by a rod-shaped rubber elastic body 6 at a fulcrum in the tracking direction and supported in both directions in the jitter direction. FIG. 2 is an enlarged perspective view of the pick-up needle 1, with reference numeral 7 indicating an electrode film. FIG. 3 is a side view of the conventional example shown in FIG. 1, and H indicates the height from the disk surface to the support point of the rod-shaped rubber elastic body 6.

Since the pickup section of a conventional disk player is constructed as described above, it has the following drawbacks. Hereinafter, the drawbacks of the above-mentioned conventional example will be described using drawings as necessary.

First, FIG. 4 shows a case where the fulcrum supporting rubber elastic body 6 is set at a position _H1 higher than the disk surface.
In the following figures, members similar to those shown in FIGS. 1, 2, and 3 are designated by the same reference numerals. FIG. 4 is a side view showing that an error of ±δ in the jitter direction occurs with respect to the disk surface runout ±d.

Next, similarly set the fulcrum supporting rubber elastic body 6 at a high position _H1 from the disk surface, and set the cantilever 3
When the angle θ between the pick-up needle 1 and the disk surface is increased, the value of the component Fsinθ in the direction perpendicular to the cantilever 3 of the frictional force F between the pick-up needle 1 and the disk increases, and as a result, the pick-up needle 1 becomes stuck to the disk. FIG. 5 shows that there is a risk that the pick-up needle 1 may fly off when the needle is turned.

Furthermore, in the double-sided fulcrum support of the cantilever 3 shown in the plan view of the pickup section in FIG. 6, the tracking control and jitter servo drive are not independent. For example, when tracking is performed in the direction of arrow A at 6-2 in FIG. 6, for the drive in the jitter direction, 6-3,
As shown in 6-4, surplus force acts in the tracking direction and affects tracking.

Further, the angle of the electrode film 7 of the pick-up needle 1 is shifted according to the tracking control. For example, as shown in FIG. 7, if the thickness of the electrode film 7 is t and the width is w, then θ ₁
If the electrode film 7 is located at a shifted position, the eighth
As shown in the figure, the thickness of the electrode film 7 is wsinθ ₁ +tcosθ ₁ . Here w is usually longer than t (w is about
1.35μ, t is approximately 0.2μ), so the value of wsinθ ₁ + tcosθ ₁ is t
(0<θ ₁ <90°). Therefore, if the angle is shifted as described above, the thickness of the electrode film 7 becomes thicker, and when picking up the signal on the disk track, adjacent signals will be picked up in addition to the target signal, and the resolution when picking up the signal will decrease. There was a risk that it would decline.

Further, when the power is cut off, such as during a power outage, the pick-up needle 1 needs to be in a lifted state. This is because if the pickup needle 1 comes into contact with the disk when the power is turned on and the disk begins to rotate, the electrode film will be damaged. Now, an electromagnet 8 for lifting up the pick-up needle 1 is separately provided. Naturally, this lift-up electromagnet 8 is also turned off during a power outage, so
At this time, the pick-up needle 1 must be lifted up by the fulcrum supporting rubber elastic body 6. The state in which the pick-up needle 1 is lifted up at the time of a power outage is shown in FIG. 9-9-1.
Furthermore, when energized, as shown in 9-2 in Figure 9,
The lift-up electromagnet 8 is turned on, and the pick-up needle 1 is pressed against the disk by this force. However, at this time, pressure is applied to the fulcrum supporting rubber elastic body 6, and if this condition continues, this fulcrum supporting rubber elastic body 6 will be adversely affected.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and the support position of the cantilever 3 is set low with respect to the disk to reduce errors in the jitter direction and prevent the pick-up needle 1 from jumping. On the premise that the cantilever 3 is prevented from bouncing, the cantilever 3 is suspended and supported via a plurality of rubber elastic bodies so as to be able to move in parallel two-dimensionally, and tracking control is performed by separately providing support for a lift system. The purpose is to remove surplus force in the tracking direction relative to the jitter drive inside, improve the resolution of the electrode film 7 during signal pickup, and reduce the pressure applied to the fulcrum supporting rubber elastic body 6.

The technical idea behind this invention is shown in Figures 10 and 11 below.
One example is shown in FIGS. 12, 13, and 14.
It is shown and explained in Fig. 15.

First, as shown in FIG. 10, if the fulcrum supporting rubber elastic body 6 is set at a position _H2 lower than the disk surface, the error in the jitter direction due to the surface runout of the disk is reduced, and the disk of the pick-up needle 1 and the error in the jitter direction are reduced. The value of the component F sin θ of the frictional force F in the direction perpendicular to the cantilever 3 becomes small, and even when the pick-up needle 1 gets stuck on the disk, there is no fear that the pick-up needle 1 will fly off. Then the first
As shown in Fig. 1, by supporting the cantilever part at three or more points so that the pick-up needle 1 can move two-dimensionally in parallel, tracking control and jitter drive become independent, and tracking against jitter drive during the tracking control is achieved. The residual force in the direction can be removed, and the tip of the pick-up needle 1 always remains parallel even in the tracking control direction.
It is possible to prevent the electrode film 7 of the pick-up needle 1 from being tilted and becoming thicker, thereby preventing a decrease in resolution during signal pick-up. Furthermore, in order to reduce the pressure applied to the support rubber elastic body 6, a lift system support may be provided separately.

Next, one embodiment of the present invention will be described with reference to the drawings. FIG. 12 is a side view showing one embodiment of the present invention. In this figure, 9 is a needle base on which a cantilever 3 including a permanent magnet 15 for electromagnetic drive is attached with three rubber elastic bodies 6;
1 is a needle holder which has an electromagnetic driving permanent magnet 16 at its end and holds the needle base 9, and 11 is an arm gauge. 12 is a hinge that connects the needle holder 10 and the arm gauge 11;
3 is a resonator having a contact portion 14 with the fly lead 2; What is shown in FIG. 12 above is a side view at the time of signal pickup.
The figure shows a state in which the needle holder 10 is lifted up by the lift-up electromagnet 8, and as a result, the pick-up needle 1 is lifted up. 1st
In the state shown in FIG. 2, the signal on the disk is picked up by the pick-up needle 1 and input to the resonator 13 via the fly lead 2 and the contact portion 14. However, in the lifted up state shown in FIG. 13, the fly lead 2 and the contact portion 14 are separated. Figure 14 is the 12th
FIG. 15 is a plan view of the cantilever portion shown in the figure, and FIG. 15 is a perspective view of the cantilever portion shown in FIG. 14. A combination of a T-shaped permanent magnet 15 for electromagnetic drive and a cantilever 3 (hereinafter referred to as the cantilever part) is attached to the needle base 9 so as to be supported at three points by three rubber elastic bodies 6, and this is further attached to the needle holder. Attach it to 10. This needle holder 10 is attached via an arm gauge 11 and a hinge 12, and is raised and lowered by a lift-up permanent magnet 16 and a lift-up electromagnet 8. Electromagnetic driving of the pickup needle 1 in the tracking direction and the jitter direction is performed by an electromagnetic driving permanent magnet 15 of the cantilever portion, a tracking correction electromagnet 4, and a jitter direction correction electromagnet 5. The tracking correction electromagnet 4 is arranged in the short side direction of the cantilever part with a gap between both ends of the cantilever part, and the jitter direction correction electromagnet 5 is arranged in the longitudinal direction of the cantilever part with a gap between it and one end of the cantilever part. It is located with. Magnetic poles are shown in each of the figures above.

In the above embodiment, the T-shaped permanent magnet 15 and the needle base 9 are supported at three points by the three rubber elastic bodies 6, and the coil 5 is used to drive the T-shaped permanent magnet 15 in the jitter direction.
As shown in FIG. 16, the cantilever part is supported at three points by rubber elastic bodies 6, contrary to the above embodiment, and the drive in the jitter direction is controlled by a U-shaped electromagnet 1.
This may be performed by repulsion or suction as described in No. 7, and the same effect as in the above embodiment can be obtained. In addition, Fig. 17 shows the first
The cantilever part shown in FIG. 6 is shown in a perspective view.

In addition, in the above embodiment, the three-point support was symmetrical with respect to the cantilever part, but the first
It is also effective even if the three-point support is asymmetrical with respect to the cantilever portion, as shown in FIG.

Further, in the above embodiment, only three-point support was explained, but four or more points of support may be used, and FIG. 19 shows a plan view of four-point support.

As mentioned above, this device is hinged to an arm cage in which a lift-up electromagnet is attached in the pick-up portion of a capacitive disk player, and is held by a needle holder to which a lift-up permanent magnet is attached. A cantilever part, in which a permanent magnet for electromagnetic driving and a cantilever are combined, is suspended and supported on a needle base via a rubber elastic body, and the cantilever part is attached with a gap from one end of the cantilever part in the longitudinal direction of the cantilever part. By arranging the jitter direction correction electromagnet, and arranging the tracking correction electromagnet in the short side direction of the cantilever part with a gap between both ends of the cantilever part, the tracking direction of the jitter drive during tracking control can be improved. The residual force can be removed, the resolution of the electrode film 7 during signal pickup can be improved, and the pressure applied to the fulcrum supporting rubber elastic body 6 can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the pickup section of a conventional disc player, Fig. 2 is an enlarged perspective view of the tip of the pick-up needle shown in Fig. 1, Fig. 3 is a side view of the pick-up needle shown in Fig. 1, and Fig. 4. FIG. 5 is a side view of a conventional example illustrating an error in the jitter direction due to surface runout of the disk, and FIG. , FIG. 6 is a plan view of a conventional example illustrating the disadvantages of tracking and jitter drive independence of the rubber elastic body supported on both sides, and FIGS. 7 and 8 are conventional examples illustrating the disadvantages of signal pickup using fulcrum support. FIG. 9 is a side view of a conventional example to explain the distortion of the supporting rubber when the cantilever part is lifted down, FIGS. 10 and 11 are diagrams to explain the technical idea of this invention, and FIG. 12 13 is a side view of an embodiment of this invention when a signal is picked up, FIG. 13 is a side view of an embodiment of this invention when the cantilever section is lifted up, and FIG. 14 is a plan view of the cantilever section of this embodiment. , FIG. 15 is a perspective view of what is shown in FIG. 14, and FIG. 16 is a plan view showing an embodiment of the invention which is supported at three points, contrary to the above-mentioned embodiment.
Fig. 17 is a perspective view of the same cantilever section, Fig. 18 is a plan view showing an embodiment with asymmetrical three-point support,
FIG. 9 is a plan view showing an example of four-point support. 1...Pick-up needle, 3...Cantilever,
6... Rubber elastic body, 8... Lift-up electromagnet, 9... Needle base, 10... Needle holder, 11
... Arm gauge, 12 ... Hinge, 15 ... Permanent magnet for electromagnetic drive, 16 ... Permanent magnet for lift-up.

Claims (1)

[Scope of utility model registration request] A pickup section of a capacitance type disk player, characterized in that a cantilever section, which is connected to a permanent magnet for electromagnetic drive and a cantilever, is suspended and supported via a rubber elastic body on a needle base which is hinged to an arm cage on which a lift-up electromagnet is attached and which is held by a needle holder on which a lift-up permanent magnet is attached, a jitter direction correcting electromagnet is arranged in the longitudinal direction of the cantilever section, with a gap between it and one end of the cantilever section, and a tracking correcting electromagnet is arranged in the short side direction of the cantilever section, with a gap between it and both ends of the cantilever section.