JPS5819907Y2 - Vibration pickup microphone - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a vibration pickup type microphone that uses a piezoelectric element to detect bone vibrations during human vocalization.

In a vibration pickup type microphone that detects human vocalizations by inserting it into the ear canal, etc., a piezoelectric element is placed inside a predetermined case, and the end of this container is used as the vibration pickup part and is tightly attached to the wall of the ear canal. The piezoelectric element is configured to detect bone vibrations during vocalization using the piezoelectric element.

In the case of conventional vibration pickup type microphones, all parts of the case are made of hard materials, so vibrations from all parts of the case other than the vibration pickup part tend to be transmitted to the piezoelectric element, which reduces the sensitivity of the microphone. If the noise level is increased, external noise or vibrations of the human body other than vocalizations may enter the system, resulting in a deterioration of the S/N ratio.

In addition, piezoelectric elements usually have a certain resonant frequency that cannot be suppressed, and their sensitivity is high near that resonant frequency (usually 1000 to 3000 Hz), so they have the disadvantage of not being able to sufficiently block external noise around this frequency. there were.

FIG. 1 shows an example of the sensitivity characteristic S and noise cutoff level R of a conventional vibrating pick-up microphone.

As is clear from this figure, in the frequency band where this vibration pickup type microphone is particularly sensitive, that is, around 2 KHz, there is a range (shaded area) where noise cannot be prevented from entering, and the S/N ratio may deteriorate.

An object of the present invention is to provide a vibration pickup type microphone that prevents noise from entering through the case and has sufficient noise isolation performance.

The vibration pickup type microphone according to the present invention prevents the intrusion of noise by applying vibration isolating means to a predetermined part of the case containing the piezoelectric element other than the vibration pickup part.
Furthermore, by matching the vibration isolation characteristics to the resonant frequency of the piezoelectric element, it is possible to effectively block noise and increase the sensitivity of voice detection.

Next, embodiments of the vibration pickup type microphone according to the present invention will be described in detail with reference to the drawings.

FIG. 2 shows a first embodiment of the invention.

In this figure, the flat-shaped piezoelectric element 2 held by the support member 1 is housed in a case 3, and a vibration pickup type microphone similar to the conventional one is formed. By bringing the pickup section 4 into close contact with the wall of the ear canal, it is possible to detect human vocalizations.

In addition, the case 3 of this vibration pickup type microphone is characterized in that the portions of the case 3 other than the vibration pickup portion formed at the tip thereof are made of a vibration isolating member.

As this vibration isolating member, a soft resin, a foamed resin, or the like may be used, and by selecting the material, etc., it is possible to match the vibration absorption characteristics to the resonant frequency of the piezoelectric element.

FIG. 3 shows -fl of the noise isolation characteristic R of the vibration pickup type microphone configured as described above.

In this example, since the piezoelectric element has a resonant frequency centered around 2 KHz, its sensitivity is high in a band centered around this frequency.

Therefore, the vibration absorption characteristics of the vibration isolating member used in case 3 are set around this frequency, and the noise isolation level R of this vibration pickup type microphone has a characteristic curved as shown in the figure.

Therefore, there is no noise intrusion near the resonant frequency of the piezoelectric element, and it is also possible to improve the sensitivity of the piezoelectric element as shown by the curve S'.

When using this vibration pickup type microphone, there is little intrusion of external noise from the back of the case 3, and the piezoelectric element detects vibrations conducted to parts other than the vibration pickup part inserted into the wall of the ear canal of the case 3. Therefore, the S/M ratio does not deteriorate due to vibrations of the human body other than vocal sounds due to exercise or the like.

Further, FIG. 4 shows a second embodiment of the vibration pickup type microphone according to the present invention.

In this embodiment, in addition to the microphone part made up of the piezoelectric element 2, the sounding part made up of the speaker 5 is housed inside the same case 3, and the vibration pickup part 4 is brought into close contact with the wall of the flow hole. The structure is such that it is possible to detect the voice and at the same time listen to the voice from the sound generation section through the sound path 6.

In this embodiment as well, the case 3 is made of a predetermined vibration isolating material except for the vibration pickup section at its tip, so the microphone section formed by the piezoelectric element 2 has the same noise rejection ability as in the above embodiment. At the same time, vibrations generated in parts such as the speaker 5 are effectively blocked, interference between the microphone part and the speaker part is reduced, and it is possible to operate the microphone part as a transmitter and a receiver alternately.

Also shown in FIG. 5 is a third embodiment of the present invention.

In this embodiment, the case 3 made of a hard member is characterized in that the portion other than the vibration pickup section 4 at the tip thereof is covered with a vibration isolating member 7.

In this method, vibrations that cause noise are not transmitted to the case 3 from the outside, and even if vibrations occur in the case 3, the vibrations are absorbed by the vibration isolating member I, so the S/
It is possible to detect voices with an excellent N ratio.

In this method, the vibration pickup section 4 may be covered with a new member having excellent vibration transmission characteristics in correspondence with the vibration isolating member 7.

The vibration pickup type microphone according to the present invention has an improved S/N ratio compared to the conventional one by applying vibration isolation means to the case part, and as a result, it is possible to increase the sensitivity of the vibration detection element. This type of vibration pickup type microphone has advantages such as expanding the scope of use and making it easier to handle.

The part of the broken case 3 to which the vibration isolating means is applied does not necessarily have to be all parts other than the tip part as in the case of the above embodiment, but may be the part that becomes a predetermined partition, the wall part of the part inserted into the ear canal, etc. It is also possible to make it only a part of case 3.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of the sensitivity characteristics and noise isolation level of a conventional vibration pickup type microphone, FIG. 2 is a cross-sectional view of the first embodiment of the vibration pickup type microphone according to the present invention, and FIG. Figure 4 is a sectional view showing the second embodiment of the vibration pickup type microphone according to the present invention, and Figure 5 is a diagram showing the sensitivity characteristics and noise isolation level of the vibration pickup type microphone shown in the figure. FIG. 7 is a cross-sectional view showing a third example of a pickup type microphone. Explanation of symbols of main parts, 1...Supporting member, 2.
...Piezoelectric element, 3...Case, 4...
... Vibration pickup section, 5 ... Speaker, 6 ... Sound path.

Claims (1)

[Scope of utility model registration request] A vibration pickup type microphone including a piezoelectric element supported by a predetermined support member, and a case having a predetermined vibration pickup portion for holding the piezoelectric element, in which at least a portion of the case is provided with vibrations around 2 KHz. A vibration pickup type microphone characterized by being provided with vibration isolating means having vibration absorption characteristics that absorb a relatively large amount of components.