JPH054400Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a microphone suitable for use in direct electrical and mechanical connection to a video camera.

BACKGROUND ART AND PROBLEMS The microphone shown in FIG. 1 has been provided as a microphone (plug-in microphone) that is directly electrically and mechanically connected to a video camera.
To briefly explain this, 10 is the lock ring, 9 is the bottom plate (board) installed inside the lock ring.
, and the plug 2 is attached thereto by penetrating it. A frame cushion 6 is made of a viscoelastic material and has a cylindrical shape. One end of the frame cushion is in contact with the bottom plate 9, and a cylindrical shield member 7 is attached to the other end. A microphone unit 3 is attached to the open end (tip) of the microphone. A printed wiring board 23 is provided behind the unit 3 within the shield member 7, and an impedance conversion circuit 21 is formed on this. If a so-called condenser microphone is configured as the unit 3, its output impedance is extremely high, so it is converted to a low impedance by the impedance conversion circuit 21 described above. A shielded wire 4 is housed within the frame cushion 6, one end of which is connected to the impedance conversion circuit 21 described above, and the other end connected to the plug 2. Therefore, the output from the unit 3 is supplied to the plug 2 through the shielded wire 4. A plug shield member 5 is provided on the inner surface of the frame cushion 6 at a position corresponding to the connection between the plug 2 and the shield wire 4.
connected to the outer conductor of This shield wire 4
Although the impedance at the connection part of the plug 2 is lowered by the impedance conversion circuit 21 described above, it is still about several kilohms, so it is easy to detect induced hum etc.
Therefore, this portion is shielded by the plug shield member 5.

Such a microphone is used by inserting the plug 2 into a jack provided in the video camera, electrically and mechanically connecting it to the video camera. The frame cushion 6 absorbs the vibration caused by the microphone so that it is not transmitted to the microphone unit 3.

As described above, conventional microphones of this type require the use of separate parts for vibration isolation and shielding, which has the disadvantage of increasing the number of parts and the number of man-hours required to manufacture them. Moreover, since the frame cushion 6 has a metal shield member on its inner surface, there is a possibility that the vibration-proofing effect of the frame cushion 6 may be impaired.

Purpose of the invention It is an object of the present invention to provide a microphone that avoids the above-mentioned drawbacks, reduces the number of parts, has a simple structure, and is easy to manufacture.

Summary of the invention The microphone of the invention includes an electrically shielded microphone unit, a plug that is electrically and mechanically connected to an electronic device, and a lead wire that supplies the output of the microphone unit to the plug. By integrally shielding the wire and the connecting portion between the lead wire and the plug with a conductive vibration isolator, the structure is simplified, the number of parts is reduced, and manufacturing is possible easily and inexpensively.

Embodiment An embodiment of the microphone according to the present invention will be described below with reference to FIGS. 2 to 5.

Note that in FIGS. 2 to 5, parts corresponding to those in FIG. 1 are given the same reference numerals, and detailed explanation thereof will be omitted.

FIG. 2 is a side view of the entire structure, and FIG. 3 is a longitudinal sectional view thereof.

In the microphone according to the present invention, the shield member 5 of the plug part is omitted from the microphone having the structure explained in FIG. 1, and the frame cushion 6 is structured as follows.

That is, it is possible to use rubber, especially a rubber with a large internal loss, such as butyl rubber, and mix it with a conductive material such as carbon powder or aluminum powder, and construct it as shown in FIGS. 4 and 5. Fourth
The figure is a side view with a part of the frame cushion 6 in cross section, and FIG. 5 is a front view.As shown in FIG. first and second step portions 6b and 6c into which the holding mold member is inserted;
A cylindrical portion 6d surrounding the lead wire 4a connecting the microphone unit 3 and the plug 2, and a third stepped portion 6 that is fitted into the inner periphery of the shield member 7.
Consists of e. Generally, the specific resistance of rubber is
The resistance is about 10 ¹⁷ Ω·cm, but this can be reduced to about 10 ³ Ω·cm by mixing carbon powder. By connecting this frame cushion 6 to the outer conductor of the plug 2 or, as in this example, to the shield member 7, it can be brought to earth potential. In this case, since almost no current flows through the frame cushion 6, the above-mentioned specific resistance of 10 ³ Ω・cm is sufficient.
A reliable ground potential area can be formed.

In addition, in the embodiment shown in FIG.
A plug 13 for power supply connection is further provided in parallel with this, through which operating current is supplied from the video camera side to the impedance conversion circuit 21 described above.

Effects of the invention According to the invention described above, the portion of the bottom plate 9 to which the plug 2 is attached, that is, the portion that directly contacts the video camera, and the microphone unit 3 are connected by the vibration-proofing material, ie, the frame cushion 6. Moreover, as shown in FIG. 1 of the conventional system, since there is no hard shielding member on the inner surface of the frame cushion 6, vibrations transmitted from the video camera to the microphone unit 3 can be largely avoided compared to the conventional system. I can do it.

In addition, since the entire frame cushion 6 is conductive, reliable shielding can be performed even at the connecting portion of the shield wire 4 and the plug 2, and the possibility of picking up induced hum etc. can be avoided. .

Furthermore, since the shield member 5 shown in FIG. 1 can be omitted, the overall structure is simplified, and the manufacturing process is also simplified.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an example of a conventional plug-in microphone, and FIG. 2 is an overall side view showing a plug-in microphone that is an example of the microphone of the present invention.
FIG. 3 is a longitudinal sectional view thereof, FIG. 4 is a partially sectional side view of a frame cushion used in this plug-in microphone, and FIG. 5 is a front view thereof. 2 is a plug, 3 is a microphone unit, 6 is a frame cushion, and 13 is a power supply plug.

Claims (1)

[Claims for Utility Model Registration] An electrically shielded microphone unit, a plug that is electrically and mechanically connected to an electronic device, and a lead wire and microphone unit that supplies the output from the microphone unit to the plug. and a conductive vibration isolator that elastically connects the conductive vibration isolator and the plug, and the lead wire and the connecting portion between the lead wire and the plug are integrally shielded with the conductive vibration isolator. A microphone characterized by: