CN221127485U - Parametric array loudspeaker - Google Patents

Abstract

The utility model discloses a parametric array loudspeaker, which comprises a mounting substrate and ultrasonic transducer arrays distributed on the outer side surface of the mounting substrate, wherein the ultrasonic transducer arrays are composed of a plurality of ultrasonic transducers distributed according to the arrays, the mounting substrate is a straight or convex curved substrate, when the mounting substrate is straight, the ultrasonic transducer arrays comprise a plurality of ultrasonic transducer subarrays distributed at intervals, the ultrasonic transducer subarrays are distributed at equal intervals or unequal intervals, and in the arrangement process from the middle of the mounting substrate to the two sides, the number of the ultrasonic transducers in the ultrasonic transducer subarrays is sequentially decreased. The utility model can enlarge the listening range of the parametric array loudspeaker and reduce the ultrasonic hazard.

Description

Parametric array loudspeaker

Technical Field

The utility model relates to the technical field of parametric array loudspeakers, in particular to a parametric array loudspeaker capable of expanding a listening range and reducing ultrasonic harm.

Background

The basic principle of a parametric array loudspeaker is to modulate an acoustic signal to be transmitted on a carrier signal of an ultrasonic frequency (f 1, f 2) and transmit it by means of an ultrasonic transducer. Self-demodulation during propagation produces a difference frequency audible sound (frequencies f1-f 2) due to the nonlinear effect of the medium, as shown in fig. 1.

Conventional parametric array speaker systems typically employ a flat rigid circuit board as a support base and use multiple identical ultrasonic transducers to form an array while transmitting ultrasonic frequencies f1 and f2, as shown in fig. 2. During forward transmission of the ultrasonic waves with frequencies f1 and f2, a virtual sound source with cumulative effect is demodulated to form an end-shooter-like situation, and absorption is approximately proportional to the square of the sound wave frequency according to the principle of sound absorption in the medium, so that the ultrasonic waves f1+f2, f1 and f2 and harmonic signals thereof are attenuated quickly, and finally only the audio signal of the difference frequency audible sound f1-f2 is remained, thereby realizing high-directivity audible sound beams and ultra-long audible sound propagation distances, as shown in fig. 3.

However, the conventional parametric array speaker uses a flat hard circuit board as a bottom board, so that ultrasonic waves propagate along the right front direction, and the formed ultrasonic intersection area is narrow, as shown by a shaded area in fig. 4. Therefore, the conventional parametric array speaker has a certain influence on the listener due to its high directivity, power and intensity in a certain area. Accordingly, there is a need for improvements over existing conventional parametric array speakers to extend the listening range and reduce the ultrasonic hazard.

Disclosure of utility model

The utility model aims to provide a parametric array loudspeaker which can enlarge the listening range and reduce the ultrasonic hazard.

In order to achieve the above object, the present utility model provides a parametric array speaker, which comprises a mounting substrate and an ultrasonic transducer array distributed on an outer side surface of the mounting substrate, wherein the ultrasonic transducer array is composed of a plurality of ultrasonic transducers arranged according to an array, the mounting substrate is a flat or convex curved substrate, when the mounting substrate is flat, the ultrasonic transducer array comprises a plurality of ultrasonic transducer sub-arrays distributed at intervals, the ultrasonic transducer sub-arrays are distributed at equal intervals or unequal intervals, and in the arrangement process from the middle of the mounting substrate to two sides, the number of the ultrasonic transducers in the ultrasonic transducer sub-arrays is sequentially decreased.

In a preferred embodiment, the curved substrate is an arc-shaped substrate, and the radius of the arc-shaped substrate is greater than 0.2m.

In a preferred embodiment, the mounting substrate is a flexible circuit board including a flexible substrate and a conductive layer formed on at least one side of the flexible substrate.

In a preferred embodiment, when the mounting substrate is a curved substrate, the plurality of ultrasonic transducers of the ultrasonic transducer array are uniformly distributed on the mounting substrate at equal intervals.

In a preferred embodiment, when the mounting substrate is a curved substrate, the ultrasonic transducer array includes a plurality of ultrasonic transducer sub-arrays distributed at intervals, and the plurality of ultrasonic transducer sub-arrays are distributed on the curved substrate at equal intervals and symmetrically.

In a preferred embodiment, when the mounting substrate is a curved substrate, the ultrasonic transducer array includes a plurality of ultrasonic transducer sub-arrays distributed at intervals, and the plurality of ultrasonic transducer sub-arrays are distributed on the curved substrate at equal intervals or unequal intervals, and in a process of arranging the ultrasonic transducer sub-arrays from the middle of the mounting substrate to two sides, the number of the ultrasonic transducers in the ultrasonic transducer sub-arrays decreases sequentially or increases sequentially.

In a preferred embodiment, the plurality of the acoustic transducer subarrays are distributed on the curved substrate at unequal intervals, and the intervals are sequentially decreased or increased from the middle of the mounting substrate to the two sides.

In a preferred embodiment, the spacing between adjacent two of the sub-arrays of ultrasound transducers is greater than 10 times the wavelength of the ultrasound waves that are the carrier wavelengths of the ultrasound waves that are loaded into the array of ultrasound transducers.

In a preferred embodiment, the rate of change of the number of ultrasound transducers of adjacent two of said sub-arrays of ultrasound transducers is less than 50%.

In a preferred embodiment, when the mounting substrate is flat, the mounting substrate is a rigid circuit board or a flexible circuit board.

Compared with the prior art, the utility model has the following beneficial effects:

The utility model designs the bottom plate of the parametric array loudspeaker into a convex curved surface shape, thereby structurally expanding an ultrasonic intersection area formed by an ultrasonic transducer array on the bottom plate compared with the existing flat bottom plate design, and further achieving the technical effects of expanding the listening range and reducing the ultrasonic hazard; or the ultrasonic transducer array on the flat bottom plate is divided into a plurality of subarrays which are distributed at intervals, and the technical effects of expanding the listening range and reducing the ultrasonic hazard are also realized by the distribution mode of the subarrays on the bottom plate.

Drawings

Fig. 1 is a schematic diagram of the sounding principle of a conventional parametric array speaker;

fig. 2 is a schematic structural diagram of a conventional parametric array speaker;

FIG. 3 is a schematic diagram of a conventional parametric array speaker forming an end-shooter-like speaker;

FIG. 4 is a schematic view of an ultrasonic intersection area formed by a conventional parametric array speaker;

fig. 5 is a schematic diagram of the parametric array speaker according to embodiment 1 of the present utility model;

Fig. 6 is a schematic structural diagram of a flexible circuit board according to embodiment 1 of the present utility model;

FIG. 7 is a schematic view of an ultrasonic intersection region formed in example 1 of the present utility model;

FIG. 8 is a schematic view of the ultrasonic reflection effect of a conventional parametric array speaker;

Fig. 9 is a schematic view of the ultrasonic reflection effect of the parametric array speaker according to embodiment 1 of the present utility model;

FIG. 10 is a schematic diagram illustrating a structure in which a plurality of sub-arrays of ultrasonic transducers of embodiment 1 of the present utility model are uniformly distributed on a flexible circuit board;

Fig. 11 is a schematic structural diagram of the multiple ultrasound transducer sub-arrays of embodiment 1 of the present utility model, wherein the multiple ultrasound transducer sub-arrays are distributed on the flexible circuit board at equal intervals, and the number of the ultrasound transducers in the ultrasound transducer sub-arrays decreases in sequence in the process of being distributed from the middle of the mounting substrate to the two sides;

Fig. 12 is a schematic structural diagram of the multiple ultrasound transducer sub-arrays of embodiment 1 of the present utility model, wherein the multiple ultrasound transducer sub-arrays are distributed on the flexible circuit board at equal intervals, and the number of the ultrasound transducers in the ultrasound transducer sub-arrays increases gradually in the process of being distributed from the middle of the mounting substrate to the two sides;

Fig. 13 is a schematic structural diagram of a plurality of ultrasound transducer subarrays of embodiment 1 of the present utility model, which are distributed at unequal intervals on a flexible circuit board, and the intervals decrease from the middle of the flexible circuit board to the two sides in sequence;

fig. 14 is a schematic structural diagram of the multiple ultrasound transducer sub-arrays of embodiment 2 of the present utility model, wherein the number of ultrasound transducers in the ultrasound transducer sub-arrays decreases in sequence in the process of being distributed on the flexible circuit board at equal intervals and from the middle of the mounting substrate to two sides;

FIG. 15 is a schematic diagram showing simulated directivity contrast of 1kHz audible sound of a conventional parametric array speaker and a parametric array speaker in an embodiment of the present application;

Fig. 16 is a schematic diagram showing the axial ultrasonic sound pressure level comparison between a conventional parametric array speaker obtained through simulation and a parametric array speaker in the embodiment of the present application.

The reference numerals are:

1. The device comprises a mounting substrate 11, a flexible substrate 12, a conductive layer 2, an ultrasonic transducer array 3, an ultrasonic transducer 4 and an ultrasonic transducer sub-array.

Detailed Description

The following detailed description of specific embodiments of the utility model is, but it should be understood that the utility model is not limited to specific embodiments.

Throughout the specification and claims, unless explicitly stated otherwise, the term "comprise" or variations thereof such as "comprises" or "comprising", etc. will be understood to include the stated element or component without excluding other elements or components.

Example 1

As shown in fig. 5, in the parametric array speaker disclosed in embodiment 1 of the present utility model, the parametric array speaker includes a mounting substrate 1 and an ultrasonic transducer array 2, and when the parametric array speaker is implemented, the mounting substrate 1 may be a convex hard circuit board or a convex flexible circuit board, and of course, the present utility model is not limited to the mounting substrate 1, and the present utility model may be applied only if the final mounting substrate 1 is convex, and in this embodiment 1, the conventional flat hard circuit board is replaced by a convex flexible circuit board, so as to be used as the mounting substrate 1 of this embodiment 1. In practice, as shown in fig. 6, the flexible circuit board may specifically include a flexible substrate 11 and a conductive layer 12, wherein the conductive layer 12 is formed on at least one side surface of the flexible substrate 11; in addition, in other alternative embodiments, the flexible circuit board may also specifically include a conductive layer 12 and two layers of flexible substrates 11 respectively covering the upper and lower surfaces of the conductive layer 12. In practice, the material of the flexible substrate 11 may be Polyimide (PI) but not limited thereto, and the conductive layer 12 may be copper. Of course, the hard circuit board and the flexible circuit board may be implemented by using circuit boards which are relatively mature in the existing market, and this embodiment 1 is not particularly limited.

In this embodiment 1, since the mounting substrate 1 is a flexible circuit board that protrudes outward, compared with the existing flat and straight hard circuit board, in this embodiment 1, the ultrasonic transducer array 2 on the mounting substrate 1 can be bent by a certain angle, that is, compared with fig. 4, the protruding flexible circuit board enlarges the ultrasonic intersection area formed by the parametric array speaker, as shown in fig. 7, the sound source radiation range of the ultrasonic transducer array 2 in this embodiment 1, and compared with the conventional parametric array speaker, the ultrasonic intersection area formed by the ultrasonic intersection area is far greater than the ultrasonic intersection area formed by the conventional parametric array speaker, and the audible sound range is correspondingly enlarged. That is, the present application can realize short-distance propagation while also expanding the range of front audible sound. In addition, compared with the existing parametric array speaker, the reflection caused by the propagation of sound waves to environments such as obstacles (such as baffles) is reduced in the embodiment 1, as shown in fig. 8, which is the sound wave reflection intensity of the existing parametric array speaker, and fig. 9, which is the sound wave reflection intensity of the parametric array speaker of the embodiment 1, it is obvious that the reflection intensity of the ultrasonic wave directly in front of the parametric array speaker is reduced in the embodiment 1, and further the ultrasonic sound pressure level directly in front of the parametric array speaker is reduced, and the ultrasonic harm to a listener is reduced.

In practice, the flexible circuit board may preferably be arc-shaped, and the radius of the arc-shaped flexible circuit board is preferably greater than 0.2m. Since the larger the radius of the flexible circuit board is at a fixed length, the smaller the angle at which the ultrasonic transducer array 2 is radiated forward, the overall directivity of the parametric array speaker can be ensured.

The ultrasonic transducer array 2 is mounted on the outer side surface of the flexible circuit board 1, and is composed of a plurality of ultrasonic transducers 3 arranged in an array. In this embodiment, the flexible circuit board is designed to be convex, so the distribution mode of the ultrasonic transducer 3 on the flexible circuit board is not particularly limited, that is, the technical effect of expanding the listening range achieved in embodiment 1 can be achieved as long as the flexible circuit board is convex.

In one embodiment, the plurality of ultrasonic transducers 3 are uniformly distributed directly on the flexible circuit board at equal intervals, and of course, the ultrasonic transducers may be distributed at unequal intervals.

In another specific embodiment, the plurality of ultrasonic transducers 3 may be divided into a plurality of ultrasonic transducer sub-arrays 4 distributed at intervals on the flexible circuit board, and the plurality of ultrasonic transducer sub-arrays 4 may be uniformly distributed or distributed at unequal intervals on the flexible circuit board. As shown in fig. 10, three ultrasonic transducer sub-arrays 4 (an array 1, an array 2 and an array 3 respectively) are distributed on the flexible circuit board, the three ultrasonic transducer sub-arrays 4 are uniformly and symmetrically distributed at intervals, and the number of the ultrasonic transducers 3 contained in the three ultrasonic transducer sub-arrays 4 and the arrangement mode of the ultrasonic transducers 3 are the same, that is, the three ultrasonic transducer sub-arrays 4 are completely the same and are uniformly distributed on the flexible circuit board at equal intervals. In the scheme, the curved arc-shaped structure can enable ultrasonic beams of the ultrasonic transducer arrays 2 with high directivity to diffuse leftwards and rightwards, on one hand, the ultrasonic intensity right in front of the ultrasonic transducer arrays 2 can be weakened, and the ultrasonic sound pressure level is reduced; on the other hand, the sound pressure level of the front audible sound can be ensured, and the audible sound ranges on the left side and the right side can be enlarged.

In yet another embodiment, the number of the ultrasonic transducers 3 in the ultrasonic transducer sub-array 4 decreases sequentially during the process of distributing the plurality of ultrasonic transducer sub-arrays 4 from the middle of the flexible circuit board to the two sides on the flexible circuit board. As shown in fig. 11, there are 5 ultrasound transducer sub-arrays 4 (array 1, array 2, array 3, array 4 and array 5 respectively) on the flexible circuit board, and the 5 ultrasound transducer sub-arrays 4 are uniformly and symmetrically distributed on the flexible circuit board at equal intervals, but preferably, in the process of distributing the 5 ultrasound transducer sub-arrays 4 from the middle to the two sides of the flexible circuit board on the flexible circuit board, the number of the ultrasound transducers 3 in the ultrasound transducer sub-arrays 4 is sequentially decreased, that is, the number of the ultrasound transducers 3 contained in the array 1 positioned at the most middle of the flexible circuit board is the largest, and secondly, the number of the ultrasound transducers 3 contained in the two ultrasound transducer sub-arrays 4 which are close to the array 1 from the left to the right, that is, the number of the ultrasound transducers 3 contained in the array 2 and the array 3 is smaller than the number of the ultrasound transducers 3 in the array 1, and secondly, the number of the two ultrasound transducer sub-arrays 4 which are close to the array 2 and the array 3 from the left to the right, that is the number of the ultrasound transducers 3 contained in the array 4 and the array 5 respectively is smaller than the number of the ultrasound transducers 3 in the array 2 and the array 3. In the scheme, the convex flexible circuit board expands the radiation range of the sound source of the parametric array loudspeaker, and the distribution mode of the ultrasonic transducers 3 on the flexible circuit board can also form a convex curved surface sound source radiation area, so that the scheme further expands the radiation range of the sound source of the parametric array loudspeaker on the basis of the scheme of the convex flexible circuit board.

Of course, as described above, the distribution of the ultrasonic transducers 3 on the flexible circuit board is not particularly limited in this embodiment, and other arrangements are also applicable to this embodiment 1. For example, the number of the ultrasonic transducers 3 in the ultrasonic transducer sub-array 4 is sequentially increased in the process that the plurality of ultrasonic transducer sub-arrays 4 are arranged on the flexible circuit board and can be distributed from the middle of the flexible circuit board to two sides, as shown in fig. 12. Or the plurality of ultrasonic transducer subarrays 4 are distributed on the flexible circuit board at unequal intervals, and the intervals are gradually decreased or increased from the middle of the flexible circuit board to two sides, as shown in fig. 13, the intervals among the plurality of ultrasonic transducer subarrays 4 are gradually decreased from the middle of the flexible circuit board to two sides.

Preferably, in this embodiment 1, the interval between two adjacent ultrasonic transducer sub-arrays 4 is greater than 10 times the wavelength of the ultrasonic wave, where the ultrasonic wave is the carrier wavelength of the ultrasonic wave loaded to the ultrasonic transducer array 2. If the ultrasonic wave wavelength is the ultrasonic wave carrier wave wavelength with the frequency of 40KHz, the ultrasonic wave wavelength is approximately 8.5cm (namely 340 m/40 kHz multiplied by 10). Because each group of ultrasonic transducer subarrays 4 has a certain radiation angle, if adjacent subarrays are close, sound waves radiated by the two subarrays are overlapped with each other, so that the sound pressure level is overlarge and discomfort is caused.

Preferably, in this embodiment 1, the rate of change of the number of ultrasound transducers 3 between adjacent two of the ultrasound transducer sub-arrays 4 is less than 50%. If the number of the ultrasonic transducers 3 in the middle ultrasonic transducer subarray 4 is 100, the number of the ultrasonic transducers 3 of the ultrasonic transducer subarrays 4 on the two sides adjacent to the middle ultrasonic transducer subarray is not less than 50%, namely 50, of the number of the ultrasonic transducers 3 in the middle ultrasonic transducer subarray 4, so that the sound pressure level between the two adjacent ultrasonic transducer subarrays 4 is ensured not to be suddenly changed, namely the sound pressure level distribution is ensured to be uniform.

Example 2

As shown in fig. 14, in embodiment 2 of the present utility model, a parametric array speaker includes a mounting substrate 1 and an ultrasonic transducer array 2, and in this embodiment 2, unlike in embodiment 1, the mounting substrate 1 is still flat, and in the implementation, the mounting substrate 1 may be a flat hard circuit board or a flat flexible circuit board, and of course, the present utility model is not limited to the mounting substrate 1 being necessarily a circuit board, and the present utility model may be applied as long as the final mounting substrate 1 is flat. In this embodiment 2, too, both the hard circuit board and the flexible circuit board can be implemented by using the circuit boards which are relatively mature in the existing market, and this embodiment 2 is not particularly limited.

Unlike embodiment 1, in embodiment 2, since the mounting substrate 1 is also flat, the embodiment specifically designs the distribution of the ultrasonic transducers 3 on the mounting substrate 1 so that an outwardly convex curved sound source radiation area can be formed. The ultrasonic transducer array 2 on the mounting substrate 1 is divided into a plurality of ultrasonic transducer sub-arrays 4 which are distributed at intervals, the plurality of ultrasonic transducer sub-arrays 4 are distributed at equal intervals or unequal intervals, and the number of the ultrasonic transducers 3 in the ultrasonic transducer sub-arrays 4 is gradually decreased in the process of being distributed from the middle of the mounting substrate 1 to two sides on the mounting substrate 1.

As shown in fig. 14, 5 ultrasonic transducer sub-arrays 4 (array 1, array 2, array 3, array 4, and array 5, respectively) are distributed on the mounting substrate 1, and in the process that the 5 ultrasonic transducer sub-arrays 4 are distributed on the mounting substrate 1 from the middle of the mounting substrate 1 to the two sides, the number of the ultrasonic transducers 3 in the ultrasonic transducer sub-arrays 4 decreases in sequence, that is, the number of the ultrasonic transducers 3 contained in the array 1 located at the middle of the mounting substrate 1 is the largest, and secondly, the number of the ultrasonic transducers 3 contained in the two ultrasonic transducer sub-arrays 4 near the array 1 on the left and right, that is, the number of the ultrasonic transducers 3 contained in the array 2 and the array 3 is smaller than the number of the ultrasonic transducers 3 in the array 1, and secondly, the number of the ultrasonic transducers 3 contained in the two ultrasonic transducer sub-arrays 4 near the array 2 and the array 3 on the left and right, that is the number of the ultrasonic transducers 3 contained in the array 4 and the array 5, respectively, is smaller than the number of the ultrasonic transducers 3 in the array 2 and the array 3. In this scheme, due to the distribution of the ultrasonic transducers 3 on the mounting substrate 1, a convex curved sound source radiation area can be formed, so that the technical effect of expanding the radiation range of the sound source of the parametric array loudspeaker can be achieved.

In addition, as in the above embodiment 1, the interval between two adjacent ultrasonic transducer sub-arrays 4 in the embodiment 2 is also greater than 10 times of the ultrasonic wavelength, and the rate of change of the number of the ultrasonic transducers 3 between the two adjacent ultrasonic transducer sub-arrays 4 is also less than 50%, which is described in the above embodiment 1, and details are not repeated here.

The technical effects of the present utility model will be described with reference to simulation results of a specific embodiment

In this specific embodiment, the ultrasonic carrier frequency of the parametric array speaker is 40kHz, the entire ultrasonic transducer array on the mounting substrate is 0.2m long, the radius of the mounting substrate is 0.2m, and the directivity pair of 1kHz audible sound is obtained through simulation, as shown in fig. 15. In fig. 15, the gray dotted line indicates the directivity of the conventional parametric array speaker, and the black dotted line indicates the directivity of the parametric array speaker in this embodiment. From the figure, compared with the prior parametric array loudspeaker, the utility model greatly expands the listening range. In addition, fig. 16 is a simulation result of axial ultrasonic sound pressure level comparison. In fig. 16, the gray dotted line is the ultrasonic sound pressure level of the conventional parametric array speaker, and the black dotted line is the ultrasonic sound pressure level of the parametric array speaker in this specific embodiment. Compared with the prior parametric array loudspeaker, the utility model obviously reduces the ultrasonic sound pressure level, thereby reducing the ultrasonic hazard.

The utility model has the advantages that the bottom plate of the parametric array loudspeaker is designed into a convex curved surface shape, so that compared with the existing flat bottom plate design, the ultrasonic intersection area formed by the ultrasonic transducer array on the bottom plate is structurally enlarged, thereby achieving the technical effects of enlarging the listening range and reducing the ultrasonic hazard; or the ultrasonic transducer array on the flat bottom plate is divided into a plurality of subarrays which are distributed at intervals, and the technical effects of expanding the listening range and reducing the ultrasonic hazard are also realized by the distribution mode of the subarrays on the bottom plate.

The foregoing descriptions of specific exemplary embodiments of the present utility model are presented for purposes of illustration and description. It is not intended to limit the utility model to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain the specific principles of the utility model and its practical application to thereby enable one skilled in the art to make and utilize the utility model in various exemplary embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the utility model be defined by the claims and their equivalents.

Claims (10)

1. The parametric array loudspeaker is characterized by comprising a mounting substrate and ultrasonic transducer arrays distributed on the outer side face of the mounting substrate, wherein the ultrasonic transducer arrays are composed of a plurality of ultrasonic transducers distributed according to the arrays, the mounting substrate is a straight or convex curved substrate, when the mounting substrate is straight, the ultrasonic transducer arrays comprise a plurality of ultrasonic transducer subarrays distributed at intervals, the ultrasonic transducer subarrays are distributed at equal intervals or unequal intervals, and in the distribution process from the middle of the mounting substrate to the two sides, the number of the ultrasonic transducers in the ultrasonic transducer subarrays is sequentially decreased.

2. A parametric array speaker as in claim 1, wherein the curved substrate is an arcuate substrate having a radius greater than 0.2m.

3. A parametric array speaker as in claim 1, wherein the mounting substrate is a flexible circuit board comprising a flexible substrate and a conductive layer formed on at least one side of the flexible substrate.

4. A parametric array loudspeaker as in claim 1, wherein when the mounting substrate is a curved substrate, the plurality of ultrasonic transducers of the ultrasonic transducer array are equally spaced apart on the mounting substrate.

5. A parametric array loudspeaker as in claim 1, wherein when the mounting substrate is a curved substrate, the ultrasound transducer array comprises a plurality of spaced apart ultrasound transducer sub-arrays, the plurality of ultrasound transducer sub-arrays being equally spaced and symmetrically disposed on the curved substrate.

6. A parametric array loudspeaker according to claim 1, wherein when the mounting substrate is a curved substrate, the ultrasonic transducer array includes a plurality of ultrasonic transducer sub-arrays distributed at intervals, the plurality of ultrasonic transducer sub-arrays are distributed on the curved substrate at equal intervals or unequal intervals, and in a process of arranging the ultrasonic transducer sub-arrays from the middle of the mounting substrate to two sides, the number of ultrasonic transducers in the ultrasonic transducer sub-arrays decreases sequentially or increases sequentially.

7. A parametric array speaker as in claim 6, wherein a plurality of said sound transducer sub-arrays are distributed at unequal intervals on said curved substrate with the intervals decreasing or increasing sequentially from the middle of the mounting substrate to the two sides.

8. A parametric array loudspeaker as in any one of claims 1-7, wherein the spacing between adjacent ones of the sub-arrays of ultrasonic transducers is greater than 10 times the wavelength of the ultrasonic wave carrier wave applied to the array of ultrasonic transducers.

9. A parametric array loudspeaker as in any one of claims 1-7, wherein the rate of change of the number of ultrasound transducers of adjacent ones of the sub-arrays of ultrasound transducers is less than 50%.

10. A parametric array speaker as in claim 1, wherein when the mounting substrate is flat, the mounting substrate is a rigid circuit board or a flexible circuit board.