JPH06113397A - Dual-drive speaker provided with diffusion resonance attenuation - Google Patents

Abstract

PURPOSE: To obtain a more uniform, that is, more constant output reply by configuring a speaker with 1st and 2nd piezoelectric drive elements and a means that couples an electric signal with the 1st and 2nd piezoelectric drive elements. CONSTITUTION: A loudspeaker phone 14 of a loudspeaker 10 has a throat end, a 1st piezoelectric drive element, and a cone diaphragm 22 is provided with two wires in a diverter 20 fitted nearly adjacent to the throat and used to couple an electric signal to the 1st piezoelectric drive element 22-1. Furthermore, the 2nd piezoelectric drive element 24-1 coupled with a 2nd diaphragm is arranged substantially in a diverter 16-2, and a 2nd wire pair is coupled with the 2nd piezoelectric drive element 24-1 to couple an electric signal with the 2nd piezoelectric drive element 24-1. Furthermore, an adhesive layer made of a 1st prescribed material and coupled with a 1st buffer is provided adjacent to an upper side to the piezoelectric drive elements, and a 2nd buffer on the 2nd piezoelectric drive element 24-1 is configured by an elastomer layer coupled with the piezoelectric drive elements.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker. More particularly, the present invention relates to piezoelectric driven speakers.

[0002]

BACKGROUND OF THE INVENTION In speaker technology, it is known that the sensitivity of piezoelectric speakers is not constant but varies with frequency. These variations in speaker output in response to a constant voltage input signal are due to various factors.
One reason piezoelectric speakers do not have a constant output over a range of frequencies is because of the speaker's driving element.
ent) and the natural resonance frequency of the diaphragm structure. The sensitivity of the speaker increases when the input frequency corresponds to the resonant frequency of the drive element and the diaphragm structure.

[0003]

In a so-called dual drive audio speaker, a single horn is coupled to two or more separate drive elements and the drive elements and diaphragm structure have a common resonant frequency. , The peaks and valleys of the frequency response will be similar to those of a single drive element speaker. Therefore, the prior art could be improved by having a dual drive speaker with a more uniform or more constant output response.

[0004]

To solve the above problems, a dual drive (horn tweeter) audio speaker according to the present invention comprises a horn having a throat capable of receiving at least two drive elements and an output. A first piezoelectric drive element coupled to a first conical diaphragm disposed substantially adjacent the throat, the first piezoelectric drive element being coupled to a first shock absorber of a first layer of predetermined material. An element and a second piezoelectric drive element coupled to a second conical diaphragm disposed substantially adjacent the throat, the second piezoelectric drive element being coupled to a second shock absorber of a second predetermined layer of material. A dual drive audio speaker comprising two piezoelectric drive elements and means for coupling an electrical signal to said first and second piezoelectric drive elements for improved frequency response.

[0005]

DETAILED DESCRIPTION FIG. 1 shows a perspective view of a dual drive piezoelectric audio speaker (10). The speaker (10) shown in FIG.
Uses piezoelectric drive elements, which are well known in the art for use in so-called horn tweeters and other high frequency speakers, and speaker systems. The dual drive audio speaker (10) shown in FIG. 1 clearly shows the output opening of a mouse or horn (12) from which audio sound waves diverge. (The selection of drive elements in a piezoelectric speaker is bi-morph, or lead zirconate titanate or PZT mono-morph.
A (mono-morph) layer in combination with a central vane or back plate layer made of metal. ) FIG. 2 shows an exploded view of the speaker (10) shown in FIG. The speaker horn (14)
It has two separate throat openings or orifices, each having a throat end and, as shown in FIG. 2, identified by reference numbers (16-1, 16-2) respectively. The horn mouse has the reference number (12) in FIG.
Are identified by. Two phasing flags (18-1, 18-2) match the impedance between the air and the diaphragm and prevent out-of-phase pressure waves from canceling each other out.

The diverter (20) is sized and shaped to receive the diaphragm and the piezoelectric drive element (22, 24) to efficiently transmit acoustic waves from the diaphragm and drive element. An opening having a predetermined size and shape is provided for coupling to the throat of the horn (14).

A first piezoelectric drive element and a conical diaphragm (22) are mounted within the diverter (20) substantially adjacent the throat and couple an electrical signal to the first piezoelectric drive element (22-1). It is equipped with two wires used for this purpose. The second piezoelectric drive element (24-1) coupled to the second diaphragm is also located substantially within the diverter (16-2) as shown. Second
The wire pair also sends an electrical signal to the second piezoelectric drive element (24-1).
Coupled to a second piezoelectric drive element for coupling to.

A pair of metal terminals (26, 28) are coupled to the wires coupled to the piezoelectric drive elements and extend through the rear cover (30). Rear cover (30)
Is attached to the diverter (20) by a plurality of attachment screws (32).

FIG. 3 shows a cross-sectional view of the first piezoelectric drive element and diaphragm, identified by the reference numeral (22) in FIG. In FIG. 3, the first piezo drive element comprises a bi-morph piezo drive, which consists of two piezoceramic disks mounted on opposite sides of a thin metal disk. (The structure and operation of mono-morph and bi-morph piezoelectric drive elements are known in the art.) The invention disclosed herein, for that purpose, is either a bi-morph or mono-morph drive element. It works together with. Only the bi-morph drive element is depicted in this figure for simplicity and clarity. Those skilled in the art will recognize that the mono-morph element lacks one of the piezoceramic discs (220) depicted as reference numeral (240) in FIGS. 3 and 4.

The piezoelectric drive element (consisting of layers 220, 222) is bonded to the speaker cone (230) using any suitable method, including, for example, a suitable adhesive. Adjacent to the upper surface of the piezoelectric drive element is an adhesive layer (226) that joins a first dampener or buffer element (228) of a first predetermined material. In the preferred embodiment, this adhesive layer (226) is an aluminum stiffener.
ffener) (228) when used with the buffer itself.

The preferred embodiment had a first shock absorber, which was essentially an adhesive layer (226) supported by an aluminum stiffener. In this first shock absorber, the adhesive itself became a shock absorber. The second shock absorber on the second drive element consisted of an elastomer layer bonded to the piezoelectric drive element.

In an alternative embodiment of the invention, first and second shock absorbers of the same or nearly the same material but having different masses could be included. A first shock absorber, which is coupled to the first drive and comprises a first material having a first mass, shifts the frequency response of the speaker by a first amount.
A second shock absorber made of the first material and coupled to the second drive, but having a second mass different from the first mass, shifts the frequency response of the speaker by a second amount. If one were to implement an example using the same material with different masses, one would have used elastomer-based shock absorbers of different thickness. As a further example, it is possible to add lead to an elastomer shock absorber of virtually the same thickness, which
Their mass can be changed with little change in thickness.

Still another embodiment of the present invention is conceivable in which first and second shock absorbers having the same mass but different elastic moduli are provided. When a rigid support plate is bonded to the piezoelectric drive element, for example by a suitable adhesive, the stiffness of the support plate affects the frequency response of the drive element. Changing the stiffness of the drive can change the frequency response of the speaker. Thus, a damper having first and second moduli of elasticity, respectively coupled to the first and second drive elements, can be used to alter the characteristics of the speaker.

In the preferred embodiment, the first bumper on the first piezoelectric drive element comprises an adhesive layer supported by a layer of aluminum, preferably between 0.05 and 0.25 mm. The second piezoelectric drive element, identified by the reference numeral (24) in FIG. 2, is shown in cross section in FIG. The second piezoelectric drive element consists of a piezoelectric layer (240) sandwiched on either side of the central vane layer (242). As mentioned above, the structure and operation of a piezoelectric drive element for a speaker is known in the art and will not be described in detail here.

An adhesive layer (246) is used to couple a second shock absorber (248) of a second predetermined material to the drive element. This second shock absorber, like the first shock absorber, is used to change the resonance frequency of the second drive element (24) from the resonance frequency of the first drive element shown in FIG. In the preferred embodiment, the second shock absorber is an elastomer layer, preferably about 0.50 to 1.5 mm neoprene.
It is made of rubber. By using different types of buffers on each piezoelectric drive element, the resonant frequency of each of the drive elements can be varied, resulting in an output signal when their individual outputs are applied to a single horn. The frequency response of is even more constant than that obtained by only one of the drive elements or the combination of the outputs of two drive elements with the same type of buffer on both sides. In the case of the drive element shown in FIG. 3, the shock absorber is an adhesive supported by aluminum, but the combination of the low mass, relatively stiff aluminum layer and the adhesive reduces the resonant frequency of the drive (22). Acts to increase. For example, another metal such as brass or copper could work as well. Other shock absorbers include
Some would include layers of the same material but different masses. Such materials can include, for example, lead-containing elastomers. The combination of the higher mass elastomeric shock absorber with its own adhesive will reduce the resonant frequency of the drive element shown in FIG. It is therefore clear that the output frequency response obtained by the combination of the drivers with different damping elements is somewhat flat in the frequency range of interest, ie 3 KHz and 25 KHz.

In the preferred embodiment, the piezoelectric drive element is a
It was a morph or a two layer bender. (These piezoelectric layers are typically lead zirconate titanate,
Other materials can work as well). One of ordinary skill in the art will appreciate that mono-morph drive elements are equally acceptable.

The aluminum buffer layer in the preferred embodiment had a thickness of between approximately 005 mm and 025 mm. The thickness of the elastomeric layer is approximately equal to 0.05 mm.

[Brief description of drawings]

FIG. 1 is a perspective view showing a dual drive piezoelectric audio speaker with improved frequency response.

FIG. 2 is an exploded perspective view of elements of the speaker shown in FIG.

3 is a cross-sectional view of the piezoelectric drive element and diaphragm structure shown in FIG.

4 is another cross-sectional view of the piezoelectric drive element and diaphragm structure, also shown in FIG.

[Explanation of symbols]

 10 Double Drive (Horn Tweeter) Audio Speaker 14 Horn 22-1 First Piezoelectric Drive Element 24-1 Second Piezoelectric Drive Element 228 First Buffer 230 First Cone Diaphragm 248 Second Buffer 250 Second Cone Diaphragm

Claims (10)

[Claims] 1. A dual drive (horn tweeter) audio speaker (10) with improved frequency response: a horn (14) having a throat and an output capable of receiving at least two drive elements; A first piezoelectric drive element (22-1) coupled to an adjacently disposed first conical diaphragm (230), the first piezoelectric drive element (22-1) coupled to a first shock absorber (228) of a first predetermined material layer. The first piezoelectric drive element (22-1); a second conical diaphragm (250) disposed substantially adjacent to the throat.
A second piezoelectric drive element (24-1) coupled to
The second piezoelectric drive element (24-1) coupled to a second shock absorber (248) of a second layer of predetermined material; means for coupling electrical signals to the first and second piezoelectric drive elements;
A dual drive audio speaker characterized by comprising. 2. The dual drive audio speaker (10) according to claim 1, wherein the first shock absorber (228) comprises a metal layer and a predetermined adhesive layer. Driving audio speaker. 3. The dual drive audio speaker (10) of claim 1, wherein the second shock absorber (248) is bonded to the second piezoelectric drive element by an adhesive layer. A dual drive audio speaker characterized by comprising. 4. The dual drive audio speaker (10) according to claim 1, wherein said first piezoelectric drive element (22-).
1) is a dual-driving audio speaker, which is a mono-morph piezoelectric driving unit. 5. The dual drive audio speaker (10) according to claim 1, wherein said second piezoelectric drive element (24-
1) is a dual-driving audio speaker, which is a mono-morph piezoelectric driving unit. 6. The dual drive audio speaker (10) according to claim 1, wherein said first piezoelectric drive element (22-).
1) A double-driving audio speaker, which is a bi-morph piezoelectric driving unit. 7. The dual drive audio speaker (10) of claim 1, wherein the second piezoelectric drive element (24-
1) A double-driving audio speaker, which is a bi-morph piezoelectric driving unit. 8. The dual drive audio speaker (10) of claim 3, wherein the elastomer layer is approximately 0.5.
A dual drive audio speaker having a thickness between 0 mm and 1.50 mm. 9. A dual drive (horn tweeter) audio speaker (10) with improved frequency response: a horn (14) having a throat and an output capable of receiving at least two drive elements; A first piezoelectric drive element (22-1) coupled to an adjacently disposed first conical diaphragm (230) and coupled to a first shock absorber (228) having a first mass, The first
Piezoelectric drive element (22-1); a second piezoelectric drive element (24-1) coupled to a second conical diaphragm (250) located substantially adjacent the throat and having a second mass. Said second piezoelectric drive element (24-1) coupled to a second shock absorber (248);
And a means for coupling to a second piezoelectric drive element; a dual drive audio speaker. 10. A dual drive (horn tweeter) audio speaker (10) with improved frequency response: a horn (14) having a throat and an output capable of receiving at least two drive elements; substantially adjacent to said throat. A first piezoelectric actuating element (22-1) coupled to a first conical diaphragm (230) arranged in parallel with the first shock absorber (228) having a first elastic modulus, A first piezoelectric drive element (22-1); a second piezoelectric drive element (24-1) coupled to a second conical diaphragm (250) located substantially adjacent to the throat,
A second piezoelectric drive element (24-1) coupled to a second shock absorber (248) having a modulus of elasticity; means for coupling an electrical signal to the first and second piezoelectric drive elements. Characteristic dual drive audio speaker.