A sound focusing device for voiceprint monitoring and preparation method thereof

Abstract

The present invention discloses a sound focusing device for voiceprint monitoring and a preparation method thereof. The sound focusing device is a cone structure, including a front end and a rear end. The front end is horn-shaped, and the inner wall surface of the front end is a microstructure presenting a pattern array, and the microstructure of the pattern array is formed by laser etching; the monitored sound wave frequency is 50Hz to 10kHz, and the sound wave enters the sound focusing device from the entrance of the front end, is reflected by the microstructure of the pattern array on the inner wall surface, and is transmitted from the exit of the rear end. The sound pressure at the outlet of the rear end is 4 to 8 times that of the sound pressure at the entrance of the front end. The sound focusing device provided by the present invention expands the receiving range of sound waves of power equipment, especially plays a sound focusing effect on weak sound waves, and realizes intelligent diagnosis of power equipment based on voiceprint monitoring.

Description

Technical Field

[0001] The present invention relates to the technical field of voiceprint monitoring, and in particular to a sound focusing device for voiceprint monitoring and a preparation method thereof. Background Art

[0002] During operation, power equipment will generate weak acoustic signals due to loose cores or partial discharge. Experienced maintenance personnel can qualitatively judge whether the equipment has faults based on the abnormal sounds emitted by the power equipment. However, this manual identification method is inefficient, time-consuming, labor-intensive, subjective, and relies on the engineering experience of the inspectors. It is limited to the audible frequency band and has a narrow sound wave frequency band. It cannot achieve real-time ultrasonic frequency band monitoring of power equipment and cannot meet the requirements of power equipment monitoring.

[0003] At present, in order to judge the operating status of power equipment by using sound parameters and reflect the different operating status of different power equipment, it is necessary to use equipment to collect voiceprints and conduct patrol monitoring of power equipment. A typical example is the low-frequency ultrasonic detection technology used in the insulation diagnosis of high-voltage equipment. Since the use of sound to monitor the operating status of power equipment can achieve contactless and lossless measurement, acoustic voiceprint detection technology has been vigorously promoted. With the several innovations in signal transmission technology and the advent of the big data era, acoustic voiceprint monitoring technology has gradually developed towards intelligence and networking.

[0004] For example, patent CN114280436A provides an FP ultrasonic sensor array implantation device for monitoring partial discharge of power equipment, which is composed of an FP ultrasonic sensor support, an FP ultrasonic sensor array, and an optical fiber terminal. The array can be implanted inside a power equipment with a coaxial structure of a bushing and a current transformer, and can sensitively and quickly detect ultrasonic signals generated by partial discharge in various parts of the power equipment such as the bushing, body, lead wire, coil, etc. The detection range can cover an ultrasonic frequency band of 20kHz to 300kHz. However, this technical solution still has certain limitations. The monitored sound wave frequency band is narrow, and weak acoustic signals cannot be monitored, and the intelligent standard of voiceprint monitoring of power equipment cannot be fully realized.

[0005] The sound focusing device used in voiceprint monitoring technology is a key component of voiceprint monitoring. Existing technologies mostly focus on the design and improvement of its mechanical structure. However, the problem of large monitoring sound loss has always existed, which seriously affects the monitoring effect of the voiceprint of power equipment.

[0006] Therefore, providing a sound focusing device with high sound wave reflectivity and low loss rate to achieve the effect of improving voiceprint monitoring is an urgent problem to be solved by those skilled in the art. Summary of the invention

[0007] In view of the defects existing in the above-mentioned prior art, the present invention provides a sound focusing device and preparation method for voiceprint monitoring, adopts the idea of ​​material surface micro-processing, and uses ultrafast laser micro-nano processing technology to control the size and morphology of the acoustic microstructure on the inner surface of the sound focusing device, and etches a microstructure of a pattern array on the inner wall surface of the trumpet-shaped front end of the sound focusing device to achieve customized processing, increase the control of sound waves on the inner surface of the sound focusing device, and enhance the directivity of sound. In particular, the pattern array is set as a U-shaped groove array, the corresponding groove width and depth are set, and the inclination angle of the trumpet-shaped front end is adjusted accordingly, so that the loss rate of the collected sound waves is reduced and the reflectivity is increased.

[0008] In a first aspect, the present invention provides a sound focusing device for voiceprint monitoring, characterized in that the sound focusing device is a cone structure, including a front end and a rear end, the front end is horn-shaped, and the inner wall surface of the front end is a microstructure presenting a pattern array, and the microstructure of the pattern array is formed by laser etching;

[0009] The monitored sound wave frequency is 50Hz~10kHz. The sound wave enters the sound focusing device from the front end entrance, is reflected by the microstructure of the pattern array on the inner wall surface, and is transmitted from the rear end outlet. The sound pressure at the rear end outlet is 4~8 times that of the front end entrance.

[0010] The sound focusing device used for soundprint monitoring of power equipment adopts the idea of ​​material surface micro-processing. The size and morphology of the acoustic microstructure on the inner surface of the sound focusing device are regulated by ultrafast laser micro-nano processing technology. A pattern array microstructure is etched on the inner wall surface of the horn-shaped front end of the sound focusing device, thereby increasing the control of sound waves by the inner surface of the sound focusing device and enhancing the directivity of the sound.

[0011] Furthermore, the sound focusing device is made of metal or plastic, the length of the front end is 5-30 cm, the length of the rear end is 2-10 cm, and the surface roughness of the inner wall of the rear end is 0.1-1 μm.

[0012] By setting the dimensions of the front and rear ends of the sound focusing device, the sound waves can be reflected on the inner wall surface of the front end and then reflected by the relatively smooth surface of the rear end, so as to realize the collection and monitoring of weak acoustic signals generated by power equipment, which not only prolongs the path of sound wave reflection, but also does not increase the number of reflections, and reduces the loss of weak sound waves during the collection process of the sound focusing device. At the same time, it is more convenient to perform micro-structure processing on the inner wall surface of the horn-shaped structure at the front end, while ensuring the processing accuracy.

[0013] Furthermore, the pattern array is a U-shaped groove array structure, and the U-shaped groove array is a rectangle;

[0014] The U-shaped groove array includes a plurality of U-shaped grooves arranged in parallel, each U-shaped groove has the same size, the width of each U-shaped groove is 200-400 μm, and the spacing between two adjacent U-shaped grooves is 18-22 μm;

[0015] Each U-shaped groove includes a central groove and at least two layers of edge steps. The depth of the central groove is 40-50 μm, and the width of each layer of edge steps is 20-30 μm.

[0016] The inner wall surface of the front end is set as a U-shaped groove array. By setting the deep and shallow layers on the inner wall surface, the reflection path of weak sound waves in the entire internal space of the sound collecting device is extended, and the edge steps set in the U-shaped grooves can play a transitional role in the reflection of the sound waves, reducing the loss of weak sound waves in the reflection process.

[0017] Furthermore, the relationship between the inclination angle of the front end and the center groove depth, edge step width and monitored acoustic wave parameters of each U-shaped groove is as follows:

[0018]

[0019] in, is the phase change of the sound wave after it is reflected by the U-shaped groove, φ is the additional phase of the sound wave incident on the U-shaped groove interface, is the difference compared to the smooth inner wall surface, λ is the wavelength of the sound wave, l is the width of each U-shaped groove, d is the total width of the single-side edge step of each U-shaped groove, H is the absolute value of the height difference between the sound wave reflection and the sound wave incident, h is the depth of the central groove, α is the inclination angle of the front end, β is the reflection angle of the sound wave through the U-shaped groove interface, γ is the incident angle of the sound wave incident on the U-shaped groove interface, x is the lateral coordinate value of the point where the sound wave is incident on the U-shaped groove interface, is the derivative value of the changing phase of the sound wave at the point with the transverse coordinate value x and x.

[0020] Based on the width of the U-shaped groove, the depth of the center groove and the width of the edge step, and the corresponding setting of the inclination angle of the front end speaker, the phase of the sound wave after reflection through the U-shaped groove is increased, thereby increasing the reflectivity of the sound wave. On the basis of increasing the reflectivity of the sound wave, based on the values ​​of the width of the U-shaped groove, the depth of the center groove and the width of the edge step, combined with the inclination angle of the front end speaker, the reflection angle of the sound wave through the U-shaped groove interface is increased, and the number of reflections is small, thereby reducing the loss of the sound wave in the collection and propagation of the sound focusing device.

[0021] Furthermore, the relationship between the depth of the central groove, the width of each U-shaped groove, and the total width of the single-side edge step of each U-shaped groove is:

[0022]

[0023] Wherein, l is the width of each U-shaped groove, d is the total width of the single-side edge step of each U-shaped groove, h is the depth of the central groove, α is the inclination angle of the front end, which is 15° to 60°, and the value range of R is 0.1 to 0.65.

[0024] When the numerical range of the inclination angle of the front end portion is set, which conforms to the relationship between the inclination angle of the front end portion and the central groove depth, edge step width and monitored sound wave parameters of each U-shaped groove of the U-shaped groove array, the reflectivity of the weak sound waves collected by the sound focusing device is increased by about 15 to 25% compared with the weak sound waves collected on the smooth inner wall surface, and the loss rate of the sound waves is reduced by about 15 to 25%.

[0025] In a second aspect, the present invention further provides a method for preparing the above-mentioned sound focusing device, comprising the following steps:

[0026] A sound focusing device prefabricated into a cone structure, the sound focusing device comprising a front end portion and a rear end portion;

[0027] Planning the path of the laser beam based on the pattern array on the inner wall surface of the front end of the sound focusing device;

[0028] Setting the parameter values ​​of the laser, wherein the parameter categories of the laser include laser pulse width, laser wavelength, power range and scanning speed;

[0029] According to the laser focusing method, a laser focusing device is built to focus the laser beam emitted by the laser;

[0030] The laser is started to perform laser etching on the inner wall surface of the front end portion to prepare a microstructure of the inner surface of the sound focusing device.

[0031] An ultrafast laser processing method is used for the inner wall surface of the front end of the sound focusing device to form a microstructure presenting a pattern array. The laser processing has high precision and can also realize customized processing of complex patterns on the inner wall surface of the front end of the sound focusing device. It is suitable for weak sound wave monitoring and diagnosis of power equipment in different scenarios.

[0032] Furthermore, the path of the laser beam is planned, including:

[0033] Set the scanning mode to grid in the laser and input the path node information of the beam during the scanning process;

[0034] The gap between parallel lines in laser scanning was set to 18-22 μm, and the spot diameter of the laser was set to 13-17 μm.

[0035] Furthermore, the parameter values ​​of the laser are set, specifically including: laser pulse width of 0.001 to 1 fs, laser wavelength of 355 to 1064 nm, power range of 50 mW to 15 W, and scanning speed of 200 to 800 mm / s.

[0036] By limiting the parameters of the specific laser power of the laser and adapting to the pattern array microstructure on the inner wall surface of the front end portion 1 of the sound focusing device, it is possible to adjust the processing depth and width of the inner wall surface material, thereby preparing the pattern array microstructure of the corresponding scene.

[0037] Further, the laser focusing device includes a reflector group, a beam expander, a scanning galvanometer and an F-Theta lens, and the reflector group is used to adjust the scanning movement of the laser beam;

[0038] The beam expansion multiple of the beam expander is 2 to 4 times, the range of the scanning galvanometer is ≥ (100×100) mm, and the focal range of the F-Theta lens is ≥ (-30 to 30) mm.

[0039] Furthermore, the laser beam is focused in a positive defocusing manner, and the defocusing amount is 1 to 5 μm.

[0040] Setting the appropriate defocus can ensure the accuracy of laser processing. If the defocus is too small, the laser will cause serious damage to the inner wall surface, resulting in a rough surface, the processing accuracy of the pattern array cannot be guaranteed, and the U-shaped groove will appear conical; if the defocus is too large, the laser energy cannot be fully transmitted to the inner wall surface, and the expected pattern array microstructure cannot be formed.

[0041] The present invention provides a sound focusing device for voiceprint monitoring and a preparation method thereof, which at least have the following beneficial effects:

[0042] (1) The inner wall surface of the front end presents a pattern array microstructure, which can expand the frequency range of acoustic wave monitoring, improve the acoustic wave reflectivity, and reduce acoustic wave loss.

[0043] (2) The pattern array is designed as a U-shaped groove array structure to extend the transmission path of the sound wave in the space of the sound focusing device, reduce the number of reflections of the sound wave, improve the reflectivity of the sound wave, and reduce the loss of the sound wave; and under the conditions of the set center groove depth, groove width, edge step width and inclination angle of the trumpet-shaped front end of the U-shaped groove, compared with the smooth inner wall surface, the sound wave reflectivity is increased by 15 to 25%, and the sound wave loss rate is reduced by 15 to 25%.

[0044] (3) By adopting the laser scanning processing method, the laser beam can be matched with the pattern array microstructure, which ensures the processing speed of the pattern array microstructure on the inner wall surface of the front end and improves the processing accuracy of the microstructure. The reflectivity of the sound waves collected by the pattern array microstructure formed by laser scanning etching is improved, and the loss during the sound wave transmission process is reduced.

[0045] (4) By limiting the parameters of the specific laser power of the laser to adapt to the pattern array microstructure on the inner wall surface of the front end of the sound focusing device, it is possible to adjust the processing depth and width of the inner wall surface material, and then prepare the pattern array microstructure of the corresponding scene. The beam expansion multiple of the beam expander used to focus the laser beam, the range of the scanning galvanometer, and the focal range of the F-Theta lens can ensure the accuracy and efficiency of the pattern array microstructure processing on the inner wall surface. The combination of the scanning galvanometer and the F-Theta lens can realize high-degree-of-freedom scanning processing in three-dimensional space, which is suitable for the processing of pattern array microstructures on the inner wall surface of the horn-shaped sound focusing device. Setting an appropriate defocus amount can ensure the accuracy of laser processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 The overall structure diagram of a sound focusing device for voiceprint monitoring provided by the present invention;

[0047] Figure 2 A partial cross-sectional view of a sound focusing device for voiceprint monitoring provided by the present invention;

[0048] Figure 3 A schematic diagram of the structure of the U-shaped groove array on the inner wall surface of the front end portion in the embodiment provided by the present invention;

[0049] Figure 4 A schematic diagram of the positions of laser etching for preparing the pattern array on the inner wall surface of the sound focusing device provided by the present invention;

[0050] Figure 5 A schematic diagram of the reflection path of the sound wave under the U-shaped groove array on the inner wall surface of the front end portion in the embodiment provided by the present invention;

[0051] Figure 6 A flowchart of a method for preparing a sound focusing device provided by the present invention. DETAILED DESCRIPTION

[0052] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods. 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 are within the scope of protection of the present invention.

[0053] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0054] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0055] like Figure 1 and Figure 2 As shown, the present invention provides a sound focusing device for voiceprint monitoring, the sound focusing device is a cone structure as a whole, including a front end portion 1 and a rear end portion 2, the front end portion 1 is horn-shaped, and the inner wall surface of the front end portion 1 is a microstructure presenting a pattern array, and the microstructure of the pattern array is formed by laser etching;

[0056] The monitored sound wave frequency is 50Hz~10kHz. The sound wave enters the sound focusing device from the entrance of the front end 1, is reflected by the microstructure of the pattern array on the inner wall surface, and is transmitted from the exit of the rear end 2. The sound pressure at the outlet of the rear end is 4~8 times the sound pressure at the entrance of the front end.

[0057] The front section of the front end 1 is the entrance of the sound wave, and the rear section is the exit of the sound wave. After the sound wave is transmitted from the front end 1, it enters the rear end 2, and then enters the subsequent device of voiceprint monitoring from the rear end 2, thereby completing the collection of weak acoustic signals of power equipment.

[0058] The existing sound focusing device has a relatively smooth surface and cannot achieve directional control of reflected sound waves. The improvement of the sound focusing device in the present invention adopts the idea of ​​material surface micro-processing, and controls the size and morphology of the acoustic microstructure on the inner surface of the sound focusing device through ultrafast laser micro-nano processing technology, and etches a pattern array of microstructures on the inner wall surface of the horn-shaped front end 1 of the sound focusing device, thereby increasing the control of the sound waves on the inner surface of the sound focusing device and enhancing the directivity of the sound.

[0059] In a certain embodiment, the sound collecting device used for voiceprint monitoring can be made of metal or plastic. Of course, the front and rear ends can also be made of different materials, which is not particularly limited here. Among them, the length of the front end 1 is controlled to be 5-30cm, and the length of the rear end 2 is controlled to be 2-10cm. The inner wall surface of the front end 1 is laser etched into a microstructure with a pattern, and the inner wall surface of the rear end 2 is a relatively smooth surface with a roughness controlled to 0.1-1μm.

[0060] By setting the dimensions of the front end 1 and the rear end 2 of the sound focusing device, the sound waves can be reflected on the inner wall surface of the front end 1 and then reflected by the relatively smooth surface of the rear end 2, so as to realize the collection and monitoring of weak acoustic signals of power equipment, which not only prolongs the path of sound wave reflection, but also does not increase the number of reflections, and reduces the loss of weak sound wave signals during the collection process of the sound focusing device. At the same time, it is more convenient to perform micro-structure processing on the inner wall surface of the horn-shaped structure of the front end 1, and the processing accuracy can also be guaranteed.

[0061] In one embodiment, if Figure 3 As shown, the pattern array of the microstructure on the inner wall surface of the front end portion 1 is defined as a U-shaped groove array structure, and the shape of the entire U-shaped groove array is a rectangle;

[0062] The U-shaped groove array includes a plurality of U-shaped grooves arranged in parallel, and each U-shaped groove has the same size.

[0063] The width of each U-shaped groove is limited to 200-400 μm, and the spacing between two adjacent U-shaped grooves is limited to 18-22 μm;

[0064] Each U-shaped groove includes a central groove and at least two layers of edge steps. The depth of the central groove is 40 to 50 μm, where the depth of the central groove is the vertical depth relative to the inner wall surface of the front end portion. The width of each layer of edge steps is 20 to 30 μm. The edge steps extend layer by layer from the edge line of the U-shaped groove to the central groove position. No further restrictions are made on the layer-by-layer depth of the edge steps and the specific number of layers of the edge steps. Figure 2 The number of edge step layers given is 2.

[0065] The specific depth value of the central groove, the specific width value of the edge step, the specific number of layers of the edge step, and the specific depth value of each layer of the edge step can be limited in applicability according to different monitored power equipment.

[0066] The inner wall surface of the front end portion 1 is arranged as a U-shaped groove array. By setting the depth and shallowness of the inner wall surface in layers, the reflection path of the weak sound waves in the entire sound focusing device is extended, and the edge steps arranged in the U-shaped grooves can also play a transition role, reducing the loss of weak sound waves in the reflection process.

[0067] like Figure 4 As shown, after a sound wave in a certain direction enters the front end 1 of the sound focusing device, it is incident on the central groove of the U-shaped groove array on the inner wall surface, and is reflected and transmitted to the rear end 2, thereby realizing the collection of the sound wave. The reflection path of sound waves in other directions or angles is similar to Figure 3 Based on the embodiment of acoustic wave acquisition and monitoring for each power equipment, the incoming sound waves in all directions need to consider the relationship between the inclination angle of the front end 1 and the central groove depth, edge step width and monitored acoustic wave parameters of each U-shaped groove array.

[0068] Based on the width of each U-shaped groove, the depth of the central groove and the edge step width, and by correspondingly setting the inclination angle of the front end 1, the phase of the weak sound wave after reflection by the U-shaped groove can be increased, thereby increasing the reflectivity of the collected sound wave.

[0069] The relationship between the inclination angle of the front end portion 1 and the center groove depth, edge step width and monitored acoustic wave parameters of each U-shaped groove array is specifically as follows:

[0070]

[0071] in, is the phase change of the sound wave after it is reflected by the U-shaped groove, φ is the additional phase of the sound wave incident on the U-shaped groove interface, is the difference compared to the smooth inner wall surface, λ is the wavelength of the sound wave, l is the width of each U-shaped groove, d is the total width of the single-sided edge step of each U-shaped groove, H is the absolute value of the height difference between the sound wave reflection and the sound wave incident, h is the depth of the central groove, and α is the inclination angle of the front end.

[0072] Of course, when using the U-shaped groove array to increase the reflectivity of weak sound waves, it is also necessary to consider the loss of weak sound waves.

[0073] When weak sound waves are reflected inside the sound focusing device, in order to reduce the loss, it is necessary to minimize the number of reflections of weak sound waves. Therefore, it is necessary to ensure that the sound waves entering the front end 1 of the sound focusing device from all directions are reflected less times in the U-shaped groove, and then transmitted to the rear end 2, and then enter the sound wave monitoring and processing device at the rear end.

[0074] In order to reduce the effect of sound wave loss, it is necessary to consider increasing the reflection angle of the sound wave through the U-shaped groove interface based on the width of the U-shaped groove, the depth of the center groove and the width of the edge step, combined with the inclination angle of the front speaker, so as to reduce the number of reflections and reduce the loss of weak sound waves in the collection and transmission of the sound focusing equipment.

[0075] The relationship between the inclination angle of the front end portion 1 and the center groove depth, edge step width and monitored acoustic wave parameters of each U-shaped groove array also needs to meet the following conditions:

[0076]

[0077] Among them, β is the reflection angle of the sound wave through the U-shaped groove interface, γ is the incident angle of the sound wave on the U-shaped groove interface, and x is the lateral coordinate value of the point where the sound wave is incident on the U-shaped groove interface. is the derivative value of the changing phase of the sound wave at the point with the transverse coordinate value of x and x, λ is the wavelength of the sound wave, l is the width of each U-shaped groove, d is the total width of the single-sided edge step of each U-shaped groove, h is the depth of the central groove, and α is the inclination angle of the front end.

[0078] The relationship between the depth of the center groove, the width of each U-shaped groove, and the total width of the single-side edge step of each U-shaped groove is:

[0079]

[0080] In the formula, l is the width of each U-shaped groove, d is the total width of the single-side edge step of each U-shaped groove, h is the depth of the central groove, α is the inclination angle of the front end, and in a certain embodiment, the inclination angle of the front end 1 is 15° to 60°, and the value range of R is 0.1 to 0.65.

[0081] When the numerical range of the inclination angle of the front end portion 1 is set, which conforms to the relationship between the inclination angle of the front end portion 1 and the central groove depth, edge step width and monitored sound wave parameters of each U-shaped groove of the U-shaped groove array, the weak sound waves collected by the sound focusing device are compared with the weak sound waves collected by the smooth inner wall surface, especially the sound wave reflectivity in a specific frequency range is improved by about 15 to 25%, and the sound wave loss rate is reduced by about 15 to 25%.

[0082] At the same time, if Figure 5 As shown, the present invention also provides a method for preparing the above-mentioned sound focusing device, comprising the following steps:

[0083] A sound focusing device is prefabricated into a cone structure, the sound focusing device comprising a front end portion 1 and a rear end portion 2;

[0084] Based on the pattern array on the inner wall surface of the front end portion 1 of the sound focusing device, the path of the laser beam is planned;

[0085] Setting the parameter values ​​of the laser, wherein the parameter categories of the laser include laser pulse width, laser wavelength, power range and scanning speed;

[0086] According to the laser focusing method, a laser focusing device 3 is built to focus the laser light emitted by the laser;

[0087] The laser is started to perform laser etching on the inner wall surface of the front end portion 1 to prepare a microstructure of the inner surface of the sound focusing device.

[0088] The front end of the sound focusing device is a trumpet-shaped structure, which cannot be processed in depth by conventional processing methods, and the degree of customization is low. The present invention uses an ultrafast laser processing method for the inner wall surface of the front end 1 of the sound focusing device to form a microstructure presenting a pattern array. The laser processing has high precision and can realize customized processing of complex patterns on the inner wall surface of the front end 1 of the sound focusing device, which is suitable for weak sound wave monitoring and diagnosis of power equipment in different scenarios.

[0089] In one embodiment, planning the path of the laser beam includes the following steps:

[0090] The scanning mode is set to grid in the laser, and the path node information of the light beam during the scanning process is input; the location of the specific path node information is not limited, and it can be set according to different pattern array shapes. At the same time, the number of times the laser beam travels is not limited, so as to ensure that a high-precision and complete customized pattern array can be obtained.

[0091] The gap between parallel lines in laser scanning is set to 18-22 μm, and the spot diameter of the laser is set to 13-17 μm. The gap values ​​between parallel lines and the laser spot diameter values ​​selected here are mainly given based on the overall shape of the microstructure of the pattern array and the numerical range of depth and width. Similarly, there is no limitation on specific values. The gap values ​​between parallel lines and the spot diameter of the laser in a specific laser scan can be limited according to the weak acoustic wave characteristics of the monitored power equipment.

[0092] In a certain embodiment, the parameter values ​​of the laser are set, specifically including: laser pulse width of 0.001 to 1 fs, laser wavelength of 355 to 1064 nm, power range of 50 mW to 15 W, and scanning speed of 200 to 800 mm / s.

[0093] By limiting the parameters of the specific laser power of the laser and adapting to the pattern array microstructure on the inner wall surface of the front end portion 1 of the sound focusing device, it is possible to adjust the processing depth and width of the inner wall surface material, thereby preparing the pattern array microstructure of the corresponding scene.

[0094] In one embodiment, if Figure 6 As shown, the laser focusing device 3 includes a reflector group, a beam expander, a scanning galvanometer and an F-Theta lens, wherein the reflector group is used to adjust the scanning movement of the laser beam, and the scanning movement of the laser beam is used to achieve etching on the inner wall surface of the front end portion 1 to prepare a microstructure forming a pattern array;

[0095] The beam expansion multiple of the beam expander is 2 to 4 times, the range of the scanning galvanometer is ≥ (100×100) mm, and the focal range of the F-Theta lens is ≥ (-30 to 30) mm.

[0096] Among them, the range of the scanning galvanometer is limited to the horizontal (X-axis direction) and vertical (Y-axis direction) of the entire laser focusing plane, that is, the range of the scanning galvanometer is not less than 100×100mm. And, generally speaking, the horizontal and vertical dimensions of the scanning galvanometer are the same. The focal range of the F-Theta lens is limited to the vertical (Z-axis direction) of the entire laser focusing plane, that is, the focal range of the F-Theta lens is not less than 30mm in the vertical direction of the lens.

[0097] The values ​​of the beam expansion multiple of the beam expander used to focus the laser beam, the range of the scanning galvanometer, and the focal range of the F-Theta lens are all related to the process of processing the pattern array on the inner wall surface of the front end 1 of the sound focusing device. Within this numerical range, the accuracy and efficiency of the pattern array microstructure processing on the inner wall surface can be guaranteed. Of course, there is no special limitation on the specific numerical points here, and it can be adjusted according to the size value of the applied pattern array. The combination of the scanning galvanometer and the F-Theta lens can realize scanning processing in a three-dimensional space with a high degree of freedom, which is suitable for the processing of the pattern array microstructure on the inner wall surface of the horn-shaped sound focusing device.

[0098] In one embodiment, the laser beam is focused in a positive defocusing manner, and the defocusing amount is 1-5 μm.

[0099] The defocus is the distance between the laser beam and the inner wall surface of the front end 1 of the sound focusing device. Setting a suitable defocus can ensure the accuracy of laser processing. If the defocus is too small, the laser will cause serious damage to the inner wall surface, resulting in a rough surface, the processing accuracy of the pattern array cannot be guaranteed, and the U-shaped groove will appear conical; if the defocus is too large, the laser energy cannot be fully transmitted to the inner wall surface, and the expected pattern array microstructure cannot be processed.

[0100] The present invention provides a sound focusing device for voiceprint monitoring and a preparation method thereof, which have the following beneficial effects:

[0101] (1) The inner wall surface of the front end presents a pattern array microstructure, which can expand the frequency range of acoustic wave monitoring, improve the acoustic wave reflectivity, and reduce acoustic wave loss.

[0102] (2) The pattern array is designed as a U-shaped groove array structure to extend the transmission path of the sound wave in the space of the sound focusing device, reduce the number of reflections of the sound wave, improve the reflectivity of the sound wave, and reduce the loss of the sound wave; and under the conditions of the set center groove depth, groove width, edge step width and inclination angle of the trumpet-shaped front end of the U-shaped groove, compared with the smooth inner wall surface, the sound wave reflectivity is increased by 15 to 25%, and the sound wave loss rate is reduced by 15 to 25%.

[0103] (3) By adopting the laser scanning processing method, the laser beam can be matched with the pattern array microstructure, which ensures the processing speed of the pattern array microstructure on the inner wall surface of the front end and improves the processing accuracy of the microstructure. The reflectivity of the sound waves collected by the pattern array microstructure formed by laser scanning etching is improved, and the loss during the sound wave transmission process is reduced.

[0104] (4) By limiting the parameters of the specific laser power of the laser to adapt to the pattern array microstructure on the inner wall surface of the front end of the sound focusing device, it is possible to adjust the processing depth and width of the inner wall surface material, and then prepare the pattern array microstructure of the corresponding scene. The beam expansion multiple of the beam expander used to focus the laser beam, the range of the scanning galvanometer, and the focal range of the F-Theta lens can ensure the accuracy and efficiency of the pattern array microstructure processing on the inner wall surface. The combination of the scanning galvanometer and the F-Theta lens can realize high-degree-of-freedom scanning processing in three-dimensional space, which is suitable for the processing of pattern array microstructures on the inner wall surface of the horn-shaped sound focusing device. Setting an appropriate defocus amount can ensure the accuracy of laser processing.

[0105] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A sound focusing device for voiceprint monitoring, characterized in that: The sound focusing device is a cone structure, including a front end and a rear end, the front end is horn-shaped, and the inner wall surface of the front end is a microstructure presenting a pattern array, and the microstructure of the pattern array is formed by laser etching; The pattern array is a U-shaped groove array structure, and the U-shaped groove array is a rectangle; The U-shaped groove array includes a plurality of U-shaped grooves arranged in parallel, each U-shaped groove has the same size, the width of each U-shaped groove is 200-400µm, and the spacing between two adjacent U-shaped grooves is 18-22µm; Each U-shaped groove includes a central groove and at least two layers of edge steps, the depth of the central groove is 40-50µm, and the width of each layer of edge steps is 20-30µm; The monitored sound wave frequency is 50Hz~10kHz. The sound wave enters the sound focusing device from the front end entrance, is reflected by the microstructure of the pattern array on the inner wall surface, and is transmitted from the rear end outlet. The sound pressure at the rear end outlet is 4~8 times that of the front end entrance.

2. The sound collecting device according to claim 1, characterized in that: The sound collecting device is made of metal or plastic, the length of the front end is 5-30cm, the length of the rear end is 2-10cm, and the surface roughness of the inner wall of the rear end is 0.1-1µm.

3. The sound collecting device according to claim 1, characterized in that: The relationship between the inclination angle of the front end and the center groove depth, edge step width and monitored acoustic wave parameters of each U-shaped groove is: ； in, is the phase change of the sound wave after it is reflected by the U-shaped groove. is the additional phase of the acoustic wave incident on the U-shaped groove interface, is the difference compared to the smooth inner wall surface, is the wavelength of the sound wave, For the width of each U-shaped groove, The total width of the single-side edge step of each U-shaped groove, is the absolute value of the height difference between the sound wave reflection and the sound wave incident, is the center groove depth, is the inclination angle of the front end; is the reflection angle of the sound wave through the U-shaped groove interface, is the incident angle of the sound wave incident on the U-shaped groove interface, is the lateral coordinate value of the point where the sound wave is incident on the U-shaped groove interface, The transverse coordinate value of the sound wave is The phase change of the point The derivative value of .

4. The sound collecting device according to claim 3, characterized in that: The relationship between the depth of the center groove, the width of each U-shaped groove, and the total width of the single-side edge step of each U-shaped groove is: ； In the formula, For the width of each U-shaped groove, The total width of the single-side edge step of each U-shaped groove, is the center groove depth, is the inclination angle of the front end, ranging from 15° to 60°, and the value range of R is 0.1 to 0.

65.

5. A method for preparing a sound collecting device as claimed in any one of claims 1 to 4, characterized in that: The steps include: A sound focusing device prefabricated into a cone structure, the sound focusing device comprising a front end portion and a rear end portion; Planning the path of the laser beam based on the pattern array on the inner wall surface of the front end of the sound focusing device; Setting the parameter values ​​of the laser, wherein the parameter categories of the laser include laser pulse width, laser wavelength, power range and scanning speed; According to the laser beam focusing method, a laser focusing device is built to focus the laser beam emitted by the laser; The laser is started to perform laser etching on the inner wall surface of the front end portion to prepare a microstructure of the inner surface of the sound focusing device.

6. The method according to claim 5, characterized in that Plan the path of the laser beam, including: Set the scanning mode to grid in the laser and input the path node information of the beam during the scanning process; The gap between parallel lines in laser scanning was set to 18-22µm, and the spot diameter of the laser was set to 13-17µm.

7. The method according to claim 5, characterized in that The parameter values ​​of the laser are set, including: laser pulse width is 0.001~1fs, laser wavelength is 355~1064nm, power range is 50mW~15W, and scanning speed is 200~800mm / s.

8. The method according to claim 5, characterized in that The laser focusing device includes a reflector group, a beam expander, a scanning galvanometer and an F-Theta lens, and the reflector group is used to adjust the scanning movement of the laser beam; The beam expansion ratio of the beam expander is 2~4 times, the range of the scanning galvanometer is ≥ (100×100) mm, and the focal range of the F-Theta lens is ≥ (-30~30) mm.

9. The method according to claim 8, characterized in that The laser beam is focused with positive defocus, and the defocus amount is 1~5µm.

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