JPS5910878Y2 - ultrasonic ceramic microphone - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an ultrasonic ceramic microphone that is used outdoors and can be applied to a rear detection device of a car.

A conventional microphone of this type will be explained with reference to FIG.

As shown in the figure, a vibrating part is constructed by bonding a piezoelectric ceramic vibrator 1 to the inside of the bottom surface of a cylindrical case 2. The thickness of the vibrating part of the case 2 is reduced from the side part in order to reduce the influence of side support. The structure is thinner than the thickness of .

Reference numeral 3 denotes a terminal plate, which is attached to the opening of the case 2 via an elastic adhesive 4.

In this case, the case has a cylindrical shape and the thickness of the side part is thicker than the thickness of the vibrating part, so the actual mass of the vibrating part increases and at the same time the Q of the vibration increases. .

Therefore, the Q of acoustic resonance was high and the band was narrow.

Furthermore, since the case shape is not structured to have a constant thickness, there is a drawback that processing costs are high.

The present invention aims to improve the conventional drawbacks and provide an ultrasonic ceramic microphone with a highly sensitive and broadband sealed structure.

An embodiment of the present invention will be described with reference to FIG.

5 is a piezoelectric ceramic vibrator, which is attached to the bottom surface 6' of the truncated conical case 6.
The piezoelectric ceramic vibrator 5 is bonded to the vibrating section.

A terminal plate 7 is attached to the opening at the other end of the truncated conical case 6 via an elastic ring 8 and an elastic adhesive 9.

Lead wires 10 and 10' are connected to the electrode surface of the piezoelectric ceramic vibrator 5 and the inner surface of the truncated conical case 6, and the other end is connected to the terminal 1.
1 and 11'.

This lead wire 10. 10' is the terminal 11. 11'
Electrical signals are input and output through the lead wire 10.
10' may be used for direct output by an external person.

In this case, the shape of the terminal board 7 needs to be such that it can be easily attached to the set.

As described above, according to the present invention, by setting the truncated conical case 6, the side part is perpendicular to the vibration surface like a cylindrical case, so that the vibration is transmitted to the side part in the vertical direction. In contrast to the case where vibration damping occurs and the Q of resonance increases due to this, the vibration transmission to the side part of the truncated conical case 6 approximates the vibration direction of the vibrating part and has a certain slope with respect to the vibration surface. The vibration reaction force does not decrease.

Therefore, there is no vibration damping, and on the contrary, the vibration amplitude can be increased by resonating with the side vibration.

In addition, since the thickness of the side part of the case 6 and the vibrating part are constant, vibrations are easily transmitted to the side part and it is easy to obtain wall sensitivity, but by supporting the side part, vibration damping is be.

Therefore, the truncated conical case 6 is connected to the terminal plate 7 via the elastic adhesive 9, and the terminal plate 7 and the terminal 1
It has a structure that can be supported by 1 and 11'.

Therefore, since the structure supports the terminal plate 7 without supporting the truncated conical case 6 including the vibrating part, there is no change in characteristics due to the supporting means, and vibration distortion caused by variations in the shape of the case 6 and the lead wires 10, 10' is avoided. Since this material is absorbed by the elastic adhesive, it exhibits stable acoustic characteristics.

As described above, the present invention can provide an ultrasonic ceramic microphone exhibiting high sensitivity and wide band by setting the shape of the truncated conical case to have an excellent electrical-mechanical-acoustic conversion efficiency.

FIG. 3 shows a comparison between the frequency characteristic a of the product of the present invention and the frequency characteristic b of the conventional product.

Since the present invention has a sealed structure, it can be applied to sets used outdoors, and at the same time, it has great practicality and is expected to be applied as a detection sensor for automobiles.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a conventional ultrasonic ceramic microphone, Fig. 2 is a cross-sectional view showing an example of the ultrasonic ceramic microphone according to the present invention, and Fig. 3 is a comparison of the frequency characteristics of the inventive product and the conventional product. This is a diagram. 5...Piezoelectric ceramic vibrator, 6...Truncated conical case, 6a...Bottom surface, 7...Terminal plate, 9... Elastic adhesive.

Claims (1)

[Scope of utility model registration request] A piezoelectric ceramic vibrator is bonded to the inside of the bottom surface of one end of the truncated conical case, and the other end of the truncated conical case has an opening;
An ultrasonic ceramic microphone comprising a terminal plate attached to the opening of the case via an elastic adhesive.