Parametric array loudspeaker and low frequency compensation sound field moving system

Abstract

The parametric array loudspeaker comprises an ultrasonic transducer array, the ultrasonic transducer array comprises a plurality of sound production channels which are arranged at intervals along a first direction, each sound production channel comprises at least one ultrasonic transducer, each sound production channel is independently controlled, and the ultrasonic transducers are arranged at intervals along the first direction. During operation, part of the sounding channels are controlled to normally send audio signals, and part of the sounding channels are controlled to send low-frequency signals. According to the utility model, sound field movement and low-frequency compensation of the parametric array loudspeaker can be realized.

Description

Technical Field

[0001] The utility model relates to the technical field of directional sound generation, in particular to a parametric array loudspeaker and a sound field mobile system for compensating low frequencies. Background Art

[0002] A parametric array loudspeaker is an acoustic system that uses the nonlinear acoustic effect of a medium to generate directional sound waves. The difference frequency audible sound (frequency f1~f2) is generated by the nonlinear self-demodulation of finite amplitude ultrasound (frequency f1 and f2) through air.

[0003] During the forward transmission process, the ultrasonic frequencies f1 and f2 will be demodulated differently to produce virtual audible sound sources of frequencies f1 to f2 with a cumulative effect, forming a situation similar to an end-fire array speaker, thereby achieving a highly directive audible sound beam and an ultra-long audible sound propagation distance.

[0004] In order to achieve sound field movement or directional deflection, parametric array speakers are used in functions such as head tracking. Signal processing is usually used to adjust the phase of each channel. Phase adjustment is mainly achieved using delay to compensate for the sound path difference from each channel to the directional sound emission position.

[0005] When using multi-channel signal processing to adjust the phase of each channel, the spacing between each channel needs to be controlled to be less than the wavelength corresponding to the ultrasonic frequency, otherwise side lobes will appear in the sound field. For example, if the ultrasonic frequency is 40kHz, the corresponding sound wave wavelength is about 8.6mm, and a 0.2m wide ultrasonic transducer array requires at least 24 channels. If the ultrasonic frequency is 80kHz, the corresponding sound wave wavelength is about 4.3mm, and a 0.2m wide ultrasonic transducer array requires at least 47 channels. Therefore, the method of using multi-channel signal processing to adjust the phase of each channel requires a large number of channels, which will increase the complexity and cost of the system.

[0006] Alternatively, a multi-channel parametric speaker can be used to move the sound field, specifically by controlling the channel signal, including by controlling whether the channel is emitting sound. However, this type of multi-channel parametric array speaker usually only emits sound in some channels, and the radiation energy of these channels is mainly concentrated in the mid-high frequency, so the sound pressure of the low-frequency part of the radiated sound field is relatively small.

[0007] Therefore, it is necessary to improve the prior art to overcome the above defects in the prior art. Utility Model Content

[0008] The utility model aims to provide a parametric array loudspeaker which can realize the movement of the sound field and improve the sound pressure of the low-frequency part of the sound field, and a sound field movement system which compensates for the low frequency.

[0009] In order to solve the above technical problems, in a first aspect, the utility model proposes a parametric array loudspeaker, comprising an ultrasonic transducer array, wherein the ultrasonic transducer array comprises a plurality of sound channels spaced apart along a first direction, each of the sound channels comprises at least one ultrasonic transducer, and each of the sound channels is independently controlled, and the ultrasonic transducer array is divided into a normal sound channel for normally emitting audio signals and a low-frequency compensation channel for emitting low-frequency signals below 1 kHz, wherein the normal sound channel and the low-frequency compensation channel each comprise at least one sound channel, and during operation, the normal sound channel is controlled to emit audio signals and the low-frequency compensation channel is controlled to emit low-frequency signals, so as to perform low-frequency compensation on the sound field while forming a moving sound field.

[0010] Preferably, the normal sound emission channel is composed of a plurality of sound emission channels arranged at any continuous intervals in the ultrasonic transducer array.

[0011] Preferably, the sound waves emitted by the normal sound emission channel at least cover the target object.

[0012] Preferably, the normal sound channel is connected to the audio signal, the low-frequency compensation channel is connected to the audio signal through a low-pass filter, and the audio signal is filtered by the low-pass filter and then the low-frequency signal is output to the low-frequency compensation channel.

[0013] Preferably, the distance between the centers of two adjacent sound emission channels is 1 mm to 100 mm.

[0014] Preferably, the plurality of sound channels spaced apart along the first direction form a sound channel group, and the ultrasonic transducer array includes one or more sound channel groups arranged along one or more second directions.

[0015] Preferably, the distance between the centers of two adjacent sound channel groups is 1 mm to 100 mm.

[0016] Preferably, the first direction is arranged perpendicular to the second direction.

[0017] Preferably, the number of sound channels in each group of the sound channels is equal to the size of the ultrasonic transducer array in that direction divided by the distance between the centers of two adjacent sound channels.

[0018] Preferably, the size of the ultrasonic transducer array is 0.1m to 0.5m.

[0019] In a second aspect, the utility model also proposes a sound field movement system for compensating low frequencies, comprising:

[0020] A position acquisition module is used to acquire the position information of the target object;

[0021] A control module is connected to the position acquisition module and the parametric array speaker, and is used to control the normal sound channel corresponding to the position information in the ultrasonic transducer array to emit an audio signal according to the position information of the target object, and to control the remaining low-frequency compensation channels to emit low-frequency signals, so as to form a moving sound field and aim at the target object while performing low-frequency compensation on the sound field.

[0022] Compared with the prior art, the utility model has the following advantages:

[0023] The parametric array loudspeaker of the utility model divides the ultrasonic transducer array into a plurality of sound channels arranged at intervals, each sound channel includes at least one ultrasonic transducer, and each sound channel is controlled independently of each other. The sound field is moved by controlling the normal sound channel corresponding to the position of the target object to normally emit an audio signal. The number of channels does not need to consider the phase and spacing of each channel, so fewer channels can be used to achieve sound field movement, which is applied to functions such as head tracking. At the same time, the remaining sound channels are controlled to radiate low-frequency waves, which can achieve the effect of increasing the sound pressure of the low-frequency part of the sound field while achieving the movement of the sound field. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are only for explanation purposes and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the components in the drawings are only for illustration purposes and are used to help understand the present invention. They do not specifically limit the shapes and proportional dimensions of the components of the present invention. Under the guidance of the present invention, those skilled in the art can select various possible shapes and proportional dimensions to implement the present invention according to specific circumstances. In the drawings:

[0025] Figure 1 It is a technical principle diagram of a parametric array loudspeaker in the prior art;

[0026] Figure 2 It is a principle diagram of high directivity directional propagation of parametric array loudspeakers in the prior art;

[0027] Figure 3 It is a structural schematic diagram of a parametric array loudspeaker in the utility model;

[0028] Figure 4 It is a schematic diagram that any one ultrasonic transducer in the utility model belongs to only one channel;

[0029] Figure 5 It is another structural schematic diagram of the parametric array loudspeaker in the utility model;

[0030] Figure 6 It is a schematic diagram of the sound generation of the sound field mobile system in the utility model in one state;

[0031] Figure 7 It is a schematic diagram of the sound generation of the sound field mobile system in the utility model in another state;

[0032] Figure 8 It is another structural schematic diagram of the parametric array loudspeaker in the utility model;

[0033] Fig. 9 It is a structural schematic diagram of the sound field moving system in the utility model;

[0034] Fig.10 It is a schematic diagram of the frequency response curve of the parametric array loudspeaker before and after low-frequency compensation of the utility model. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0036] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only embodiment.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0038] like Figure 3 and Figure 4 , corresponding to a preferred embodiment of the parametric array speaker of the utility model, it includes an ultrasonic transducer array, the ultrasonic transducer array includes a plurality of sound channels 1 spaced apart along a first direction, each sound channel 1 includes at least one ultrasonic transducer 2, the ultrasonic transducer 2 is used to emit directional sound, and each sound channel 1 independently controls the sound. Figure 5As shown, the part of the sound channels corresponding to the position of the target object in the ultrasonic transducer array is defined as the normal sound channels, and the remaining sound channels are defined as the low-frequency compensation channels. During operation, the normal sound channels are controlled to emit audio signals and the low-frequency compensation channels are controlled to emit low-frequency signals, so as to form a moving sound field and perform low-frequency compensation on the sound field.

[0039] Specifically, when implementing Figure 5 to Figure 7 As shown, the normal sound channel is preferably composed of a plurality of sound channels arranged at arbitrary continuous intervals in the ultrasonic transducer array. In general, when the sound receiver is close to the left side of the ultrasonic transducer array, several sound channels 1 close to its left side in the ultrasonic transducer array are controlled to emit audio signals, and the remaining sound channels 1 emit low-frequency signals; when the sound receiver is close to the middle of the ultrasonic transducer array, several sound channels 1 close to the middle of the ultrasonic transducer array are controlled to emit audio signals, and the sound channels 1 emit low-frequency signals; similarly, when the sound receiver is close to the right side of the ultrasonic transducer array, several sound channels 1 close to its right side in the ultrasonic transducer array are controlled to emit audio signals, and the sound channels 1 emit low-frequency signals. During implementation, there is no restriction on the number of sound channels 1 in the normal sound channels that normally emit audio signals in each case, as long as it can at least cover the target object (such as when the target object is a person, specifically cover both ears of the person). As Figure 6 and Figure 7 , which is a schematic diagram of the sound generation principle of the ultrasonic transducer array at different positions of the target object.

[0040] If Figure 3 For example, the ultrasonic transducer array includes 6 sound channels 1, which are defined as the first sound channel 1 to the sixth sound channel 1 for the convenience of description. When the sound receiver approaches the left side of the ultrasonic transducer array, the first sound channel 1 to the third sound channel 1 arranged at consecutive intervals are controlled to form a normal sound channel to emit an audio signal, and the remaining sound channels 1 (i.e., the fourth sound channel 1 to the sixth sound channel 1) form a low-frequency compensation channel to emit a low-frequency signal. When the position of the sound receiver moves and moves close to the ultrasonic transducer, the sound receiver is automatically compensated for the low-frequency signal. When the middle part of the energy device array is in the middle, for example, the second sound channel 1 to the fourth sound channel 1 which are arranged at a continuous interval are controlled to form a normal sound channel and emit an audio signal, and the remaining sound channels 1 (i.e., the first sound channel 1, the fifth sound channel 1, and the sixth sound channel 1) form a low-frequency compensation channel and emit a low-frequency signal, or the fourth sound channel 1 to the sixth sound channel 1 which are arranged at a continuous interval are controlled to form a low-frequency compensation channel and emit a low-frequency signal, and the remaining sound channels 1 (i.e., the first sound channel 1 to the third sound channel 1) form a low-frequency compensation channel and emit a low-frequency signal.

[0041] When implementing, Figure 6 and Figure 7As shown, the normal sound channel is connected to the audio signal, and the low-frequency compensation channel is connected to the audio signal through a low-pass filter. The audio signal is directly input to the normal sound channel for directional output. At the same time, the audio signal is filtered by the low-pass filter and outputs a low-frequency signal below 1kHz to the low-frequency compensation channel, which is output by the low-frequency compensation channel to perform low-frequency compensation on the sound field while forming a moving sound field. Figure 6 and Figure 7 Specifically, it is a 10-channel parametric array loudspeaker with a size of 640mm×300mm. The loudspeaker transmits signals through two channels ( Figure 6 Specifically, the 5th and 6th sound channels, Figure 7 Specifically, the sixth and seventh sound channels are used to realize the sound field at different positions, and the remaining channels are used to compensate for the low-frequency signals below 1kHz. On the one hand, the audio signal is input into the normal sound channel to realize the movement of the sound field, and on the other hand, it passes through a low-pass filter with a cutoff frequency of 1kHz and is input into the low-frequency compensation channel to realize low-frequency compensation, thereby effectively making up for the low-frequency deficiency of the parametric array speaker.

[0042] like Figure 3 and Figure 4 As shown, there is a certain distance d1 between the centers of two adjacent sound channels 1, and the distance d1 is adapted to the moving accuracy of the moving sound field. For example, if the accuracy is high, the number of sound channels will increase accordingly, thereby reducing the distance between the sound channels, and vice versa. The theoretical basis for setting the distance between the sound channels is that the distance between each sound channel is controlled to be smaller than the wavelength corresponding to the ultrasonic frequency. Preferably, the distance d1 between the centers of two adjacent sound channels 1 is set between 1mm and 100mm. It should be explained that the distance between two adjacent sound channels 1 here is Figure 3 The distance between the longitudinal center axes of the two sound emission channels 1.

[0043] Further, a plurality of sound channels 1 arranged along the second direction are defined to form a sound channel group 3, such as Figure 5As shown, the ultrasonic transducer array also includes one or more groups of sound channel groups 3 arranged along one or more second directions, and the number and direction of the second direction are not limited. Preferably, the number of the second direction is one, and the second direction is arranged perpendicular to the first direction, so that the sound channels in one or more groups of sound channel groups 3 can be arranged in a square array in the direction of the X-axis and the Y-axis, so that the sound field can move more evenly. Of course, a reference point can also be selected in the first direction, the reference point and the first direction form a first reference line, the reference point and the second direction form a second reference line, and the angle between the first reference line and the second reference line is 0° to 360°, so that an irregular arrangement of sound channels can be formed to adapt to different application scenarios. Correspondingly, the spacing d2 between the centers of two adjacent sound channel groups 3 is also adapted to the moving accuracy of the moving sound field. The reason can be seen from the spacing d1 setting between the centers of two adjacent sound channels 1, which will not be further elaborated here.

[0044] There is no restriction on the arrangement of the ultrasonic transducers 2 in the ultrasonic transducer array. It can be arranged in a conventional square array or a circular array, or it can be arranged in an irregular shape. Different arrangements are suitable for different sound channel 1 arrangement scenarios, making the parametric array speaker more flexible. The number of sound channels 1 in each sound channel group 3 is adapted to the size of the ultrasonic transducer array in that direction and the moving accuracy of the moving sound field. The number of sound channels 1 is equal to the size of the ultrasonic transducer array in that direction divided by the distance between the centers of two adjacent sound channels 1. For example: the ultrasonic frequency is 40kHz, the required moving accuracy of the moving sound field is 20mm, and the width of the ultrasonic transducer array in that direction is 0.2m. Then, the number of sound channels 1 required is at least 10. Compared with the at least 24 channels required by the prior art method of using multi-channel signal processing to adjust the phase of each channel, the number of sound channels is greatly reduced, thereby effectively reducing the system complexity and cost. Accordingly, the size of the ultrasonic transducer array in any direction is adapted to the moving accuracy of the moving sound field and the sound pressure level requirements. Typically, the size of the ultrasonic transducer array is between 0.1 m and 0.5 m.

[0045] like Fig.10 The figure shows a frequency response curve of a parametric array speaker before and after low-frequency compensation in a specific embodiment. In this embodiment, there is an 8-channel parametric array speaker of 640mm×300mm, of which two sound channels are normal sound channels to achieve sound field movement, and the remaining six sound channels are low-frequency compensation channels. Before low-frequency compensation, the parametric array speaker attenuates at a rate of 12dB / oct below 1kHz. Through the low-frequency compensation channel, the sound pressure level below 1kHz can be increased by about 6dB, thereby compensating for the low low-frequency radiation of the parametric array speaker.

[0046] like Fig. 9As shown, the utility model also proposes a sound field movement system for compensating low frequencies, which can be applied in scenes such as head tracking, including:

[0047] Position acquisition module 4, used to acquire the position information of the target object. For example, a camera or ultrasonic positioning technology can be used to identify the position of the target object, and transmit the position information of the target object to the control module;

[0048] The control module 5 is connected to the position acquisition module 4 and the ultrasonic transducer array, and is used to control the normal sound channel corresponding to the position information in the ultrasonic transducer array to emit an audio signal according to the position information of the target object, and to control the remaining low-frequency compensation channels to emit low-frequency signals, so as to form a moving sound field and aim at the target object while performing low-frequency compensation on the sound field.

[0049] During specific implementation, the corresponding control mode may be pre-stored in the control module 5, and the corresponding control mode may be called according to the collected position information of the target object.

[0050] For example, in the above specific embodiment, the ultrasonic transducer array has a total of 6 sound channels, and four modes are pre-stored in the control module 5, namely mode 1: sound channels 1, 2, and 3 send audio signals, and sound channels 4, 5, and 6 send low-frequency signals, mode 2: channels 2, 3, and 4 send audio signals, and channels 1, 5, and 6 send low-frequency signals, mode 3: channels 3, 4, and 5 send audio signals, and sound channels 1, 2, and 6 send low-frequency signals, mode 4: channels 4, 5, and 6 send audio signals, and sound channels 1, 2, and 3 send low-frequency signals. When the target object approaches channels 1, 2, and 3, mode 1 is enabled, and when the target object approaches channels 2, 3, and 4, mode 2 is enabled, and so on.

[0051] like Figure 6 and Figure 7As shown, taking the head tracking scene as an example, a camera or ultrasonic positioning technology is usually used to identify the position of the head, and the position of the head is transmitted to the control module 5. By controlling the corresponding normal sound channel to send an audio signal, the corresponding low-frequency compensation channel sends a low-frequency signal. When the head moves, the position acquisition module 4 updates the target position in real time, and the control module 5 controls the corresponding normal sound channel to send an audio signal in real time, and other low-frequency compensation channels send low-frequency signals to achieve the movement of the sound field and aim at the target object and perform low-frequency compensation on the sound field. During implementation, the distance between the parametric array speaker and the head is preferably between 0.5m and 3m, so that the sound emitted by the parametric array speaker can be better received by people, and the width of the sound channel 1 is preferably 15cm to 30cm, which is compatible with the width of the head, so that interference with other areas can be reduced and point-to-point reminders can be performed. Furthermore, preferably, the width of the entire parametric array speaker is 300 mm, the total number of sound channels 1 is 16, and the distance between two adjacent sound channels 1 is between 10 mm and 100 mm, which can better control the cost, obtain a better sound pressure level, and have better sound field movement accuracy.

[0052] It should be understood that the above description is for illustration and not for limitation. Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present teachings should not be determined with reference to the above description, but rather with reference to the foregoing claims and the full scope of equivalents to which such claims are entitled. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended to be a waiver of the subject matter, nor should it be considered that the applicant has not considered the subject matter as part of the disclosed utility model subject matter.

Claims

1. A parametric array loudspeaker, characterized in that: It includes an ultrasonic transducer array, which includes a plurality of sound channels spaced apart along a first direction, each of the sound channels includes at least one ultrasonic transducer, and each of the sound channels is independently controlled. The ultrasonic transducer array is divided into a normal sound channel for normally emitting audio signals and a low-frequency compensation channel for emitting low-frequency signals below 1 kHz, and both the normal sound channel and the low-frequency compensation channel include at least one sound channel. During operation, the normal sound channel is controlled to emit audio signals and the low-frequency compensation channel is controlled to emit low-frequency signals, so as to perform low-frequency compensation on the sound field while forming a moving sound field.

2. The parametric array loudspeaker according to claim 1, characterized in that: The normal sound emission channel is composed of a plurality of sound emission channels arranged at random continuous intervals in the ultrasonic transducer array.

3. The parametric array loudspeaker according to claim 1, characterized in that: The sound waves emitted by the normal sound emission channel at least cover the target object.

4. The parametric array loudspeaker according to claim 1, characterized in that: The normal sound channel is connected to the audio signal, and the low-frequency compensation channel is connected to the audio signal through a low-pass filter. After the audio signal is filtered by the low-pass filter, the low-frequency signal is output to the low-frequency compensation channel.

5. The parametric array loudspeaker according to claim 1, characterized in that: The distance between the centers of two adjacent sound-emitting channels is 1 mm to 100 mm.

6. The parametric array loudspeaker according to claim 1, characterized in that: The plurality of sound emission channels spaced apart along the first direction form a sound emission channel group, and the ultrasonic transducer array includes one or more sound emission channel groups arranged along one or more second directions.

7. The parametric array loudspeaker according to claim 6, characterized in that: The distance between the centers of two adjacent sound channel groups is 1 mm to 100 mm.

8. The parametric array loudspeaker according to claim 6, characterized in that: The first direction is arranged perpendicular to the second direction.

9. The parametric array loudspeaker according to claim 1, characterized in that: The size of the ultrasonic transducer array is 0.1m to 0.5m.

10. A sound field moving system for compensating low frequency, characterized in that: include: A position acquisition module is used to acquire the position information of the target object; A control module is connected to the position acquisition module and the parametric array speaker according to any one of claims 1 to 9, and is used to control the normal sound channel corresponding to the position information in the ultrasonic transducer array to emit an audio signal according to the position information of the target object, and to control the remaining low-frequency compensation channels to emit low-frequency signals, so as to form a moving sound field and aim at the target object while performing low-frequency compensation on the sound field.

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