JPS58105699A - Piezo-electric loudspeaker - Google Patents

Abstract

PURPOSE:To prevent occurrence of abnormal phenomena, such as resonance phnomenon, etc., by stretching a flexible damping film between the peripheral part of the diaphragm and a frame and fixing the central part of the diaphragm to the top of a supporting projected piece united with the frame in one body. CONSTITUTION:A piezo-electric body 2 is glued on the surface of a diaphragm 1 of a metallic thin plate of a loudspeaker, with a conductive bonding agent, and the diaphragm 1 is also used as the electrode of the piezo-electric body 2. An electrode 3 is formed on the surface of the piezo-electric body 2 and a flexible damping film 7 is stretched between the peripheral part of the diaphragm 1 and a frame 8. Moreover, the central part 4 of the diaphragm 1 is fixed to the top of a supporting projected piece 9 formed together with the frame 8 in one body. The central part 4 of the diaphragm 1 is connected to one end of a lead wire 5 and the other end of the wire 5 is connected to a signal source 6, and then, the signal source 6 is connected with the frame 8 through a lead 11. According to such a constitution, occurrence of abnormal modes, such as resonance phenomenon, etc., can be inhibited, because the central part 4 is firmly fixed and the damping film 7 is installed. In addition to the above, an opening 12 which increases the effect is formed in the frame 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a support piece of a piezoelectric speaker that supports the center of a diaphragm.

A diaphragm in which a piezoelectric material that vibrates in the radial direction is laminated to a flat metal plate in the vibration direction causes bending vibration. A piezoelectric speaker that utilizes this vibration generally has the periphery of the diaphragm fixed to a frame, and only the middle part vibrates. This method has a simple structure and is widely used, but since the periphery of the diaphragm is fixed, its vibrations are concentrated in the center, making it impossible to obtain effective sound pressure. In order to effectively increase this sound pressure, it may be possible to consider a structure in which the center of the diaphragm is fixed and the peripheral portion vibrates.The present invention relates to a method for fixing the center of the diaphragm in this structure.

In order for the periphery of the diaphragm to maintain a normal vibration mode, the center must be firmly fixed.

The present invention is based on this idea, and nine embodiments will be described in detail below with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention, and in the figure, 1
is a speaker diaphragm made of a thin metal plate. 2 is a piezoelectric material which causes deformation in the radial direction when a voltage is applied to both halves thereof. Its negative side is pasted to a diaphragm 1 with a conductive adhesive, and the diaphragm 1 also serves as one electrode of the piezoelectric body 2. 3 is another electrode plate of the piezoelectric body 2, the center 4 of which is connected to one end of the lead wire 5 with solder or conductive adhesive, and the other end of the lead #J5 is connected to one pole of the signal source 6. ing. Reference numeral 7 denotes a damping membrane, which is made of a flexible material such as paper, and is stretched between the periphery of the diaphragm 1 and a frame to be described later, forming a waveform as shown in the figure. Although it does not interfere with normal vibrations in the surrounding area, it has the role of suppressing abnormal phenomena such as resonance phenomena.

Reference numeral 8 denotes a frame, and by integrating a support protrusion 9 at the center of the frame, the diaphragm 1 obtains electrical continuity with the frame 8, and its center portion is fixed, while its circumferential portion can vibrate.

2 and 3 show other embodiments of the invention. In this embodiment, the frame 8 is made of sheet metal, and an approximately semicircular opening 12 is provided at the bottom thereof concentrically with the frame, and a support protrusion 9 is provided extending from the center of the diameter of the semicircle. It is bent as clearly shown in FIG. 3, and the center of the diaphragm 1 is fixed at the point with a half-inch or conductive adhesive in the same way as in FIG. 1. In this case, the fixing work can be performed using the opening 12.

FIG. 4 shows yet another embodiment of the invention. In this embodiment, the frame 8 is made of resin molding and has an opening 12 at the bottom.
In addition, the support protrusion 9 is fixed by embedding a metal support.

The present invention described above has the effect that the support protrusion can be firmly attached to the frame.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of one embodiment of the present invention, FIG. 2 is a perspective view of a wall portion of another embodiment of the present invention, FIG. 3 is a partially enlarged sectional view of the same embodiment, and FIG. Figure 3 is a perspective view of another embodiment wall to the east; 1... Vibration plate, 2... Piezoelectric body, 7... Braking membrane, 8
... Frame, 9... Support protrusion, 12... Opening. Patent applicant Matsushita Electric Industrial Co., Ltd. Figure 1

Claims (2)

[Claims] (1) In a piezoelectric subica in which a piezoelectric material that vibrates in the radial direction is attached to a diaphragm made of a thin metal plate parallel to the vibration direction, a flexible damping film is stretched between the periphery of the diaphragm and the frame. The central part of the vibrating plate is fixed with solder or conductive adhesive to the apex of a supporting protrusion made integrally with the frame, and power is supplied to one electrode of the piezoelectric body through this supporting protrusion. Features a piezoelectric subica. (2) The support protrusion extends from the edge of the opening at the center of the bottom plate having an opening in the sheet metal frame;
A piezoelectric subica according to item (1) of the patent application, characterized in that the piezoelectric subica is bent at a right angle and made to stand upright. (3) The piezoelectric subica according to claim 1, wherein the support protrusion is molded from resin and has a base of a metal protruding boss embedded in the center of a frame bottom plate having an opening.