Patent Translate Powered by EPO and Google Notice This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate, complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or financial decisions, should not be based on machine-translation output. DESCRIPTION JPS4870628 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 are longitudinal sectional views of a condenser microphone according to the present invention. In the figure, 1 is a case, 2 moving plates, 5 is a back electrode, 6 is an insulating material, and 9 is a set screw. DETAILED DESCRIPTION OF THE INVENTION The present invention can freely convert the directivity characteristics of a microphone between omnidirectionality and unidirectionality, and yet has high dust resistance. Condenser microphone-Example 1 of this invention About-If Cf & dA, it will provide the rooster rooster. FIG. 1 shows a first embodiment of the present invention, in which 1 is a case of a cylindrical shape. Above the inside of the case 1 ', the diaphragm 2 has its circumferential concave upper surface vibrating ring 5 (1 48-70628-02 The lower surface is surrounded by the spacer 4 and positioned and fixed for a second. A back electrode 5 is fixed by an insulating material 6 in a place separated by a spacer 4 by a spacer 4 on the back surface of the vibration 2. A weir 7 protrudes from the back surface of the back electrode 5, and the weir 7 penetrates the center of the above-mentioned insulating material 6 located on the back surface of the back electrode 5. The insulating material 6 is backed with porous plastic, and has an electrical insulating effect on the case IK as well as a filtering effect on the back electrode 5. As a material of this insulating material 6, even if it is a thing other than a porous plastic, if it is porous, it can be used. . Between the back electrode 5 and the insulating material 6, a chamber 8 of an appropriate volume is formed. At the lower end portion of the case 10, a female screw is engraved 9, and a II-song-like set screw 9 is screwed into the inside to hold the insulating material 6. In the microphone configured in this way, the insulating material 6 can be easily exchanged 1: if the set screw 9 is collectively removed. If various different ones are prepared, it is possible to select the ratio between the sound pressure sensitivity from the front of the diaphragm 2 and the sound pressure sensitivity from the rear of the diaphragm 2. Therefore, microphones Ij, i can be obtained by freely converting directivity characteristics between omnidirectionality and unidirectionality. The second embodiment shown in FIG. 2 corresponds to 03-05-2019 1 the second embodiment of the present invention, which is a modification of the first embodiment. Therefore, the second embodiment shown in FIG. A common symbol is attached to, and the description of the structure of this part is omitted. The back of the back electrode 5 has a collar 7a provided with a male screw protruding, and this collar 7a is either tl penetrating the insulator 6 as in the example of @ 1 or stacked on the back of the insulation mA The two disks 10.11 provided are also pierced (tightened with a 1 ° nut 12). The odd # 5 [the holes 10a and 11a of the wedges 10a and 11a have a constant interval in the circumferential direction respectively in the first disc 10.11. When the disc 10 ° 11 is relatively rotated, the hole 10m and the hole 11110 change in degree and the acoustic resistance from the back of the slope 2h changes, so that it is more effective than the first embodiment 11 The directional characteristics can be adjusted. Since this device was configured as described above, set screw! By loosening, it is possible to freely replace several different types of insulating materials with different dimensions of W and obtain directivity characteristics according to the application. In addition, since the back of the entire microphone is completely covered with the insulating material 6, the dust resistance can be enhanced. 03-05-2019 2
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