JP5185782B2 - Vibration noise adjustment method for microphone unit - Google Patents

Description

  The present invention relates to a method for adjusting vibration noise of a microphone unit, and more particularly, to a technique for adjusting vibration noise of a microphone unit that can effectively reduce vibration noise of a dynamic microphone.

  The dynamic microphone has a relatively heavy overall mass because the voice coil is attached to the diaphragm. As a result, when vibration is applied, a relative speed difference is generated between the voice coil having inertia and the magnetic circuit unit, which becomes vibration noise.

  FIG. 3 is an explanatory view showing a microphone structure disclosed in the following Patent Document 1 proposed to reduce such vibration noise. The dynamic microphone includes a diaphragm 1, and the periphery of the diaphragm 1. The part 8 is fixed on the end surface of the unit case 3.

  In this case, the voice coil 2 attached to the back side of the diaphragm 1 is disposed in a gap of a magnetic circuit unit constituted by the permanent magnet 4, the cup-shaped yoke 5, and the electrode plate 6.

Further, the unit case 3 and the magnetic circuit unit side are connected via an elastic element 7 so that they can move relative to each other, thereby making it difficult for a relative speed difference to occur and suppressing the generation of vibration noise. I can do it.
Japanese Patent Publication No.57-9279

  On the other hand, some dynamic microphones have unidirectional characteristics that have both characteristics, in addition to bidirectional characteristics and omnidirectional characteristics. Among these, the bidirectional dynamic microphone, also called a ribbon microphone, is designed to control the mass, and the resonance frequency of the diaphragm is designed at the lower limit of the required frequency response. Further, since the omnidirectional dynamic microphone is controlled by resistance control, the resonance frequency of the diaphragm is designed to be near the center of the required frequency response.

  However, in the case of a unidirectional dynamic microphone, since it has both bi-directional and non-directional properties, the low-frequency response is limited by the resonance frequency of the diaphragm, and is about 100 Hz to 300 Hz. The resonance frequency of the diaphragm will be designed. For this reason, the low frequency component of the vibration noise has a problem that the amplitude becomes large during loudspeaking. In order to reduce such low-frequency component vibration noise, the frequency response of the diaphragm and the frequency response due to the acceleration of the magnetic circuit unit must be the same, that is, the resonance frequency between the diaphragm and the magnetic circuit unit can be reduced. Must match.

  However, in the case of the dynamic microphone shown in FIG. 3, there is no structure for matching the resonance frequencies of the diaphragm 1 and the magnetic circuit unit, so that the magnetic circuit unit has a frequency different from the vibration of the diaphragm 1. When it vibrates, there was a disadvantage that a larger vibration noise was generated than when the magnetic circuit unit was not vibrated.

  The present invention provides a vibration noise adjusting method for a microphone unit that can prevent the generation of large vibration noise by matching the resonance frequencies of a diaphragm and a magnetic circuit unit in a dynamic microphone in view of the above-described problems of the prior art. For the purpose.

The present invention has been made to achieve the above object, and uses a unit case partitioned into a one-side space portion having a front opening and a second-side space portion having a rear opening through a partition wall. A first step of interposing a first piezoelectric element between the partition wall and the weight in the other side space, and a second piezoelectric element interposed between the partition wall. with the magnetic circuit unit disposed in the one side space portion, a second step of tensioning the diaphragm to the front opening side to position the voice coil to the magnetic circuit unit comprises the void, said A voltage generated by the first piezoelectric element under a driving force proportional to the weight of the weight by vibrating the unit case that has undergone step 2 so that the magnetic circuit unit and the diaphragm are in the same direction. To the second piezoelectric element Pressure to be the most important feature that at least a third step of driving the magnetic circuit unit in the vibration direction in the same direction of the vibration plate.

  In this case, in the third step, the weight applied to the magnetic circuit unit can be varied by changing the weight of the weight. The weight is adjusted so that the output of the voice coil is minimized when the unit case is vibrated, and the UV curable resin is cured when the output of the voice coil is minimized. The weight may be fixed.

  According to the present invention, the magnetic circuit unit can equivalently increase the vibration speed as the driving force without changing its mechanical dimensions. Vibration noise can be adjusted without taking into account changes in acoustic characteristics. In other words, the diaphragm and magnetic circuit unit are vibrated in the same direction with the unit case, so that the relative speed difference does not occur between the diaphragm and the magnetic circuit unit so that the respective driving forces are the same. Vibration noise can be canceled.

  In this case, in the third step, the adjustment weight can be put into the recessed portion protruding from the other side space of the unit case to easily change the overall weight on the weight side, so that the driving force applied to the magnetic circuit unit is also simple. Can be varied. Further, the entire weight on the weight side may be fixed by irradiating and curing the filled ultraviolet curable resin with ultraviolet rays when the output of the voice coil is minimized.

  FIG. 1 is an explanatory view showing an example of a microphone unit to which the present invention is applied as a cut end face, and includes a one-side space 13 having a front opening 14 and a rear opening 16 through a partition wall 12. A unit case 11 partitioned from the side space 15 is used.

  The diaphragm 21 stretched on the front opening 14 side of the unit case 11 is formed with a voice coil 23 on the back surface 22 side.

  Furthermore, the magnetic circuit unit 31 accommodated in the one side space 13 of the unit case 11 is composed of a permanent magnet 32, a cup-shaped yoke 33, and an electrode plate 34, and includes a voice coil 23 provided in the diaphragm 21. A gap 35 for placement is provided between the cup-shaped yoke 33 and the electrode plate 34 to form the whole.

  The method of the present invention performed using such a constituent member includes a first step in which the first piezoelectric element 41 and the weight 42 are integrated and disposed in the other-side space portion 15, and the magnetic circuit unit 31 in the second step. A second step of arranging the diaphragm 21 with the piezoelectric element 51 in the one side space 13 and a voltage generated by the first piezoelectric element 41 by vibrating the unit case 11 to the second piezoelectric element 51. It is performed through at least a third step of applying and driving it.

  Here, these steps will be described in more detail. In the first step, the first piezoelectric element 41 whose one side surface 41a is closely disposed on the side of the partition wall 12 and the other ones of the first piezoelectric element 41 are described. The weight 42 is disposed in the other-side space 15 so that the end surface 43a on the one end 43 side is brought into close contact with the side surface 41b. Although the wiring of the first piezoelectric element 41 is not shown, it is wired in a direction in which a voltage is generated when a tensile force is applied.

  In this case, the weight 42 is formed to have a recessed portion 45 whose end surface is opened at the other end portion 44, and the recessed portion 45 side protrudes from the rear surface opening portion 16 of the other-side space portion 15. It arrange | positions in the other side space part 15 under the state.

  In the second step, the second piezoelectric element 51 whose one side surface 51a is closely arranged on the side of the partition wall 12 and the cup-like shape constituting the magnetic circuit unit 31 on the other side surface 51b of the first piezoelectric element 51. The magnetic circuit unit 31 arranged in a state where the outer surface 34 a of the bottom 34 of the yoke 33 is brought into close contact with each other is arranged in the one-side space 13. The wiring of the second piezoelectric element 51 is not shown in the figure, but is connected in a direction that contracts when a voltage is applied.

  The diaphragm 21 is stretched so that the peripheral edge 21 a is fixed to the opening edge 14 a partitioning the front opening 14 of the unit case 11 and the voice coil 23 is positioned in the gap 36. The second step is finished.

  In the third step, the diaphragm 21, the magnetic circuit unit 31, and the second piezoelectric element 51 are placed in one side space of the unit case 11 through the second step, and the first piezoelectric element 41 is placed in the other side space portion 15. First, the unit case 11 itself is vibrated using a vibrator (not shown) so that the magnetic circuit unit 31 and the diaphragm 21 are in the same direction.

  At this time, the first piezoelectric element 41 receives the vibration (tensile force) of the unit case 11 and generates a voltage under a driving force proportional to the weight of the weight 42. The voltage is applied to the second piezoelectric element 51 to drive the magnetic circuit unit 31 in the same direction as the vibration direction of the diaphragm 21.

In this case, if the vibration speed of the diaphragm 21 is v ₁ , the vibration speed of the magnetic circuit unit 31 is v ₂ , and the vibration speed of the weight 42 is v ₃ , the vibration speed v ₂ of the magnetic circuit unit 31 is The vibration speed v ₃ increases as the vibration speed v ₃ increases, and the vibration plate 21 can be driven in the same direction to match the vibration speed v ₁ of the vibration plate 21.

In other words, the magnetic circuit unit 31, it is possible to increase the vibration velocity v ₂ of equivalently as the driving force without changing its mechanical dimensions, liable to occur magnetic properties and sound when changing the mechanical dimensions The vibration noise can be adjusted without considering the change in characteristics.

  In addition, in the third step, as shown in FIG. 2, the unit case 11 is erected so that the weight 42 side is positioned upward, and is inserted into the recessed portion 45 protruding from the other side space portion 15 of the unit case 11. For example, the driving force applied to the magnetic circuit unit 31 may be easily changed by inserting an adjustment weight 46 composed of an appropriate number of small-diameter spheres and changing the overall weight on the weight 42 side.

  In this case, the overall weight on the weight 42 side is adjusted so that the output of the voice coil 23 is minimized when the unit case 11 is vibrated using a vibrator, and the filled UV curable resin 47 is used as a voice. You may make it fix by irradiating and hardening | curing an ultraviolet-ray when the output of the coil 23 becomes the minimum.

  Therefore, according to the present invention, the vibration plate 21 and the magnetic circuit unit 31 are vibrated in the same direction together with the unit case 11, so that no relative speed difference is generated between the vibration plate 21 and the magnetic circuit unit 31. The vibration noise can be canceled by adjusting the driving forces to be the same.

  In addition, since the mass on the magnetic circuit unit 31 side with respect to the sound wave is extremely larger than the mass of the diaphragm 21, the magnetic circuit unit 31 side does not vibrate due to the sound wave, and only the diaphragm 21 vibrates. As a result, a relative speed difference occurs between the two and an audio output is obtained.

An explanatory view showing an example of a microphone unit to which a method of the present invention is applied as a cut end face. Explanatory drawing which shows the weight adjustment method in the method of this invention. Explanatory drawing which shows the microphone structure currently disclosed by patent document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Unit case 12 Partition wall 13 One side space part 14 Front opening part 14a Opening edge part 15 Other side space part 16 Rear surface opening part 21 Diaphragm 22 Back surface 23 Voice coil 31 Magnetic circuit unit 32 Permanent magnet 33 Cup type yoke 34 Bottom part 34a outer surface 35 electrode plate 36 gap 41 first piezoelectric element 41a one side surface 41b other side surface 42 weight 43 one end portion 43a end surface 44 other end portion 45 recessed portion 46 adjustment weight 47 ultraviolet curable resin 51 second piezoelectric element 51a one side surface 51b Other aspects

Claims (3)

A unit case is used that is partitioned into one side space portion having a front opening and another side space portion having a rear opening through an intermediate partition wall,
A first step of disposing a weight in the other side space with a first piezoelectric element interposed between the partition wall and the first partition;
With disposing the second is interposed piezoelectric element magnetic circuit unit on the one side space portion between the in partition wall, said front opening by positioning the voice coil in the magnetic circuit unit is provided in the gap A second step of stretching a diaphragm on the side;
The unit case that has undergone the second step is vibrated so that the magnetic circuit unit and the diaphragm are in the same direction, and the first piezoelectric element is generated under a driving force proportional to the weight of the weight. And a third step of driving the magnetic circuit unit in the same direction as the vibration direction of the diaphragm by applying a voltage to the second piezoelectric element.   The method for adjusting vibration noise of a microphone unit according to claim 1, wherein in the third step, the weight applied to the magnetic circuit unit is varied by changing the weight of the weight.   The weight is adjusted so that the output of the voice coil is minimized when the unit case is vibrated, and the UV curable resin is cured at the time when the output of the voice coil is minimized. The method for adjusting vibration noise of a microphone unit according to claim 2, wherein the weight is fixed.

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