JPS6040760B2 - Manufacturing method of diaphragm for condenser microphone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a diaphragm for a condenser microphone.

FIG. 1 shows the overall structure of a conventional microphone.

In the figure, the vibrating membrane 3 is fixed to the membrane tensioning ring 1 using an adhesive and is being stretched. A suitable gap is maintained between the vibrating membrane 3 and the fixed electrode 9 which has been smoothed by a smoother 5. The fixed electrode 9 is fixedly supported by an electrode support case 7 made of an insulator, and the terminal 6 of the fixed electrode 9 passes through the center of the electrode support case 7 and is drawn out. Further, the membrane tension ring 1, fixed electrode 9, electrode support case 7, etc. are covered by an outer weight case 8, and are fixed by caulking at the lower end 8'. In the condenser micrometer constructed in this manner, the subordinate vibrating membrane is constructed as shown in FIG.

That is, 10 is a membrane ring made of an insulator such as plastic, ceramic, or glass, 11 is a vibrating membrane made of a film of plastic, etc., 12 is a metal-deposited foil deposited on the vibrating material, and 13 and 14 are membranes. This is the part of the metallized foil that is applied to the side and top surfaces of the tension ring. When manufacturing such a vibrating membrane, a membrane-stretching ring 1 is placed on the plastic film 11 before metal vapor deposition.
0 is used with adhesive, and 0 is fixed by heat fusion etc.
After this, from the top surface, the membrane tensioning ring 10 and the vibrating pus 11 are
Metal vapor deposition is performed on the entire surface including the

Thereafter, each membrane tensioning ring is cut out.
FIG. 3 schematically shows an apparatus for actually performing metal vapor deposition.

Reference numeral 3-1 is a vapor deposition layer body, 3-2 is a bell jar, and 3-3 is a chasobar which is evacuated to a vacuum by a pump or the like.

3-4 are evaporation supply tools, 3-5 are heaters, 3-6 are metals such as nickel, 3-7 are the directions in which metal molecules fly, 3-1 are membrane tension rings, and 3-11 are vibrating membranes. be.

The flying direction 3-7 of the metal molecules is directly upward near the object to be evaporated, and is parallel to the inner surface of the film tensioning ring shown in Fig. 2, and the metal is deposited on this inner surface. '
Unfortunately, conduction between the vapor deposition surfaces 12 and 14 may not be established, and the sensitivity of the microphone may be significantly reduced. Note that the vapor deposition surface 14
The outer crab case 8 is electrically conductive. One possible way to improve the above-mentioned drawbacks is to taper the inner surface of the membrane tensioning ring, as shown in FIG.

The difference from the structure in FIG. 2 is that the taper angle of 15 is smaller than 900, but this angle is preferably 600 to 750 in order to maintain the strength of the acute angle portion. however,
It is impossible to reduce this taper angle when cutting plastic materials, and if press working is used to reduce processing costs, the structure must be the same as that shown in FIG. 2. The present invention aims to improve such manufacturing defects around the vibrating membrane.

An embodiment of the present invention will be described below with reference to FIG. Figure 5 shows an outline of the pupil installation when actually performing metal hollyhose deposition. 5-- is the main body of the vapor-deposited layer, 5-2 is a bell jar, and 5-3 is a chamber that is evacuated to a vacuum by a pump or the like. There is.

5-4 is a vapor deposition jig, 5-5 is a heater, 5-6 is a metal such as nickel, 5-7 is a direction in which metal molecules fly, 5-10 is a membrane tensioning ring, and 5-11 is a vibrating membrane. .

The angle 5-8 of inclining the object to be deposited varies somewhat depending on the size of the chamber 5-3 in order to deposit a uniform thickness.
150-30o is desirable. As a result, metal can be reliably deposited on the hollyhock deposition surfaces 12 and 14 shown in FIG. 2, and electrical continuity can be reliably established in one direction. In the case of a condenser microphone, the capacitance between the diaphragm and the electrode is
Since it is 10 F, IKHZ becomes IMO, and even if the conduction resistance is 10 KO, the sensitivity loss of the microphone can be ignored. In other words, even if the deposition surfaces 12 and 14 in FIG. 2 are electrically connected in only one direction and in only a portion, the conduction resistance is less than several KQ, so there is no loss in sensitivity of the microphone. As described above, according to the present invention, there is a large degree of freedom in selecting the material and processing method for the membrane ring, and sensitivity loss of the microphone can be sufficiently prevented.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the overall structure of a conventional microphone, Fig. 2 is a side sectional view of the main part of a conventional diaphragm, and Fig. 3 is a schematic diagram of a metal vapor-deposited pupil in the above method of manufacturing the diaphragm. FIG. 4 is a sectional side view of a main part showing an example of good matching of a conventional diaphragm, and FIG. 5 is a schematic diagram of a metal vapor-deposited pupil in a method for manufacturing a diaphragm for a condenser microphone according to an embodiment of the present invention. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. A film-stretching ring made of an insulator fixed to a plastic film is provided at an angle with respect to the direction in which metal molecules fly, and metal vapor-deposited foil is provided on one side of the plastic film and on one side of the ring, and the inside of the ring is A metallized foil is provided on at least a portion of the peripheral surface, and the metallized foil on the plastic film and the metallized foil on the ring are electrically connected to each other by the metallized foil on the inner peripheral surface of the ring. A method for manufacturing a diaphragm for a condenser microphone, characterized by: