JPS5827412Y2 - Tone arm position detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tone arm position detecting device, and more particularly, to a tone arm position detecting device that can be easily attached to a record player or the like that does not have a negative habit of the tone arm position detecting device.

It is known that when playing records, tracing distortion occurs because the playback needle has a radius of curvature.

In order to remove this, it is sufficient to add the opposite distortion.

Also, the high frequency characteristics are attenuated due to the radius of curvature of the needle tip.

These differ depending on the inner and outer circumferences of the record, and naturally increase as the inner circumference increases.

In order to compensate for these, the amount of correction must be changed depending on the playback radius of the record, and for this purpose it is necessary to detect the position of the tone arm.

However, even if a correction device is added to a general record player to improve distortion and frequency characteristics, there is no output of the tone arm position, and it is impossible to correct it correctly.

In addition to these, when monitoring the playback position of a record from a remote location, the tone arm position may be detected and displayed on a meter or the like.

The present invention aims to easily detect the position of the tone arm from a general record player when these correction devices are added to the record player.

For this reason, a reflector is attached to a part of an ordinary tone arm, and this is detected by a detector provided on the player board side, so that the rotational state of the tone arm can be detected.

The present invention will be described in detail below with reference to FIGS. 1 to 3.

FIG. 1 shows an embodiment in which a reflector is attached to the tone arm of a record player.

A reflector 3 is attached to the pipe portion 2 of the tone arm 1 with screws 4 as shown in the figure.

On the other hand, a detector 5 is disposed below it.
A player board 6 is placed thereon.

The reflector and detectors 3 and 5 are arranged as shown in FIG. 2, and the reflector 3 consists of a reflecting plate 3-1 and a polarizing plate 3-2.

The detector 5 is composed of a light emitting body 7 and a light receiving body 8, and is composed of a polarizing body 8, so that light enters the light receiving body 8 through a polarizing plate 9.

Here, an explanatory diagram of the operating principle is shown in Fig. 3A.
The light passes through the polarizing plate 3-2, is reflected by the reflecting plate 31, passes through the polarizing plate 3-2 again, then passes through the polarizing plate 9, and reaches the photoreceptor 8.
receives light.

Here, light passes through the polarizing plates 3-2 and 9, and the transmitted light changes depending on the shift in the polarization axes of the polarizing plates.

This can be expressed equivalently to what is shown at the beginning of Figure 3.

As a result, the light to the photoreceptor 8 changes as the tone arm rotates, as shown in FIG. 3C.

When playing a record now, the rotation angle of the tone arm is usually around 2θ, and it is possible to obtain an output corresponding to the angle with sufficient linearity within the angular range of the inner and outer circumferences of the record.

In this case, the position of the twister 5 can be anywhere as long as it is under the object to be detected, that is, the reflector, like 5 or 5' in Figure 1. This becomes the output.

For this reason, the gap 1 for arranging the detector 5 on the player board can be relatively freely searched, making it easy to install it later on a general record player.
It is easy to install with only the lower part).

It goes without saying that the light from the light emitter can be pulse modulated to distinguish it from surrounding light.

With this invention, as described above, a position detector can be freely attached to the tone arm of an ordinary record player even after the fact, and it is now possible to use distortion correction devices, playback position display meters, etc. The effect is great.

Of course, it is clear that the rotational speed of the tone arm can be detected by differentiating the position detection output.

[Brief explanation of drawings]

Fig. 1 is a plan view of a tone arm showing one embodiment of the present invention, Fig. 2 is a side sectional view of the main part of Fig. 1, and Fig. 3 A to C are lines for explaining the principle of the present invention. It is a figure and its explanatory drawing. 1 is a tone arm, 2 is a pipe, 3 is a reflector, 5 is a detector 3-2.9 is a polarizing plate, 7 is a light emitter, and 8 is a light receiver.

Claims (1)

[Scope of utility model registration request] A tone arm having a cartridge at one end and a counter eight at the other end is rotatably pivoted to the player board, and a reflector and a first deflector are attached to the pipe section of the tone arm.
A deflection plate is removably arranged to face the player board, and a detector incorporating a light emitting element, a light receiving element, and a second deflection plate on the player board is arranged to face the first deflection plate. The tone arm position detector is configured to detect light reflected from the reflector of the tone arm via the first and second deflection plates.