Dual-unit leakproof acoustic structure and eyewear

Abstract

The application discloses a double-unit sound leakage prevention acoustic structure and glasses, the double-unit sound leakage prevention acoustic structure comprises a temple of the glasses, the temple is internally provided with a first loudspeaker and a second loudspeaker which are arranged at intervals along the length direction or the width direction of the temple, and a side of the temple facing a user's ear canal is provided with a first front sound outlet hole which is acoustically coupled with the first loudspeaker and a second front sound outlet hole which is acoustically coupled with the second loudspeaker; the opening areas of the first front sound outlet hole and the second front sound outlet hole are different, and when the temple is worn on the user's head, the distances from the first front sound outlet hole and the second front sound outlet hole to the user's ear canal are different. It can be seen from the above technical scheme that the application has the following advantages: 1. the near-field frequency response curve is smooth, and there is no need to press the peak by EQ; 2. the near-field sound waves are superposed and enhanced in phase; 3. the far-field leakage is relatively attenuated; 4. the structure is compact, and industrial production is easy.

Description

Technical Field

[0001] This application relates to the field of acoustic technology, to open acoustic products, and specifically to a dual-unit sound leakage prevention acoustic structure and eyeglasses. Background Technology

[0002] With the widespread use of open-back acoustic products (such as smart glasses and open-back ear hooks), users' demands for sound quality and privacy protection are constantly increasing. Currently, mainstream open-back products mainly adopt a single speaker and single sound outlet design. However, this type of single speaker solution has obvious technical defects: First, the speaker usually has serious sound leakage above 1000Hz, which can be easily heard by people around in quiet environments, compromising call privacy; second, in noisy environments, the external loudness of a single speaker is insufficient, resulting in a poor listening experience.

[0003] To address volume and sound leakage issues, dual-speaker solutions have emerged in the industry. While typical dual-speaker solutions (such as the co-directional dual-diaphragm technology introduced in Huawei Smart Glasses 2) offer improvements in temple design and overall volume, they merely arrange two diaphragms in the same direction, focusing primarily on enhancing overall loudness. This co-directional dual-diaphragm technology offers little improvement in the difference in far-field leakage, and its sound leakage prevention effect remains poor. It still relies on software methods that automatically lower the volume based on environmental recognition to protect privacy, failing to address far-field sound leakage at the physical structural level.

[0004] Furthermore, most existing dual-speaker designs use a structure where the two front sound holes are of the same size. This structure causes a strong resonance peak at certain frequencies (such as around 6kHz) on the frequency response curve, usually requiring post-processing with an EQ (equalizer) to suppress the peak. This not only increases the burden on the software algorithm but also causes phase changes, affecting the natural listening experience. Therefore, there is an urgent need for a dual-unit acoustic structure that can both enhance loudness and effectively suppress high-frequency leakage at the physical structure level, while simultaneously optimizing the frequency response curve. Summary of the Invention

[0005] The main technical problem addressed by this application is to provide a dual-unit sound leakage prevention acoustic structure and eyeglasses.

[0006] In a first aspect, this application proposes a dual-unit sound leakage prevention acoustic structure, including the temple of an eyeglass, wherein a first speaker and a second speaker are disposed inside the temple; the side of the temple facing the user's ear canal has a first front sound outlet hole acoustically coupled to the first speaker, and a second front sound outlet hole acoustically coupled to the second speaker; the opening areas of the first front sound outlet hole and the second front sound outlet hole are different, and when the temple is worn on the user's head, the distances from the first front sound outlet hole and the second front sound outlet hole to the user's ear canal are different.

[0007] In some alternative implementations, the area difference between the first front sound outlet and the second front sound outlet causes an inherent phase difference between the first sound wave emitted by the first speaker through the first front sound outlet and the second sound wave emitted by the second speaker through the second front sound outlet; the distance difference between the first front sound outlet and the second front sound outlet to the user's ear canal constitutes a physical path difference to compensate for the inherent phase difference, thereby forming a near-field acoustic in-phase superposition region at the user's ear canal.

[0008] In some alternative implementations, the area difference between the first and second front sound holes causes their combined frequency response curves to form a main peak near 4.5 kHz and a secondary peak near 6 kHz, wherein the sound pressure level of the secondary peak is lower than that of the main peak.

[0009] In some optional embodiments, the temple of the glasses is provided with a first rear sound outlet that is acoustically coupled to the first speaker and a second rear sound outlet that is acoustically coupled to the second speaker on the side opposite to the user's ear canal.

[0010] In some optional embodiments, a first front acoustic cavity is provided between the first loudspeaker and the first front sound outlet, and the first front acoustic cavity, the first loudspeaker, and the first front sound outlet constitute a first acoustic resonant system; a second front acoustic cavity is provided between the second loudspeaker and the second front sound outlet, and the second front acoustic cavity, the second loudspeaker, and the second front sound outlet constitute a second acoustic resonant system; the difference in the opening area between the first front sound outlet and the second front sound outlet causes the acoustic resonant frequencies of the first acoustic resonant system and the second acoustic resonant system to be different, so as to achieve natural physical frequency division between the first front sound outlet and the second front sound outlet.

[0011] In some alternative implementations, the area of ​​the first front sound outlet is larger than that of the second front sound outlet; in the frequency band above 5000 Hz, the loudness contribution of the first front sound outlet is greater than that of the second front sound outlet; in the frequency band from 3000 Hz to 5000 Hz, the loudness contribution of the second front sound outlet is greater than that of the first front sound outlet.

[0012] In some alternative implementations, the distance difference between the first front sound outlet and the second front sound outlet to the user's ear canal is between 0.8 and 1.2 cm; the area ratio of the first front sound outlet to the second front sound outlet is between 1.5 and 2.5.

[0013] In some alternative implementations, an acoustic isolation partition is provided between the first speaker and the second speaker.

[0014] In some alternative embodiments, the first speaker and the second speaker are arranged at intervals along the length of the temple; or, the first speaker and the second speaker are arranged in a staggered manner relative to the user's ear canal, one inside and one outside.

[0015] Secondly, this application proposes a pair of eyeglasses including a dual-unit sound leakage prevention acoustic structure as described in the first aspect.

[0016] As can be seen from the above technical solutions, the embodiments of this application have the following advantages: 1. Smooth near-field frequency response curve, no need for EQ peak suppression. This application achieves a natural frequency crossover effect by designing the first and second front sound outlets facing the user's ear canal as asymmetrical outlets with different opening areas. This is achieved by utilizing the acoustic impedance difference generated by the first (larger area) and second (smaller area) front sound outlets in different frequency bands. Because the area of ​​the first front sound outlet is larger than that of the second, the loudness contribution of the first outlet is mainly concentrated above 5000Hz, while the loudness contribution of the second outlet is mainly concentrated below 5000Hz to 3000Hz. Based on this physical frequency crossover structure, the combined frequency response curve of the two outlets forms a main peak near 4.5kHz and a secondary peak near 6kHz, with the sound pressure level of the secondary peak being lower than that of the main peak. Compared with existing technologies, this physical structure cleverly integrates peak-valley adjustment into the structural design, achieving a smooth, natural, and broad frequency response curve without the need for additional electronic EQ software algorithms, greatly reducing the complexity and hardware cost of product acoustic tuning.

[0017] 2. Near-field acoustic wave in-phase superposition enhancement By utilizing the "distance difference" between the physical positions of the two speakers and the human ear, and in conjunction with the inherent phase difference caused by the different aperture diameters of the sound outlets, this application achieves better sound field control. Specifically, in the near field (the user's ear canal), the center distance difference between the two front sound outlets is approximately 1 cm. The phase delay of the sound waves caused by this physical distance difference can precisely compensate for the inherent phase difference between the two front sound outlets, ensuring that the sound waves reaching the ear canal are essentially in phase and superimposed. This achieves near-field sound wave enhancement, ensuring that the user obtains greater in-ear loudness without increasing the driving power.

[0018] 3. Relative attenuation of far-field leakage In the far field (e.g., at 0 degrees directly in front of the head or 90 degrees to the side, approximately 20cm from the ear canal), the distance difference between the first and second front sound outlets and the far field measurement point is extremely small, making it impossible to form a physical path difference to compensate for the inherent phase difference as in the near field. Therefore, the first and second sound waves cannot form a near-field acoustic in-phase superposition region in the far field, meaning they fail to achieve in-phase superposition gain. Under the same driving power, the near-field position experiences in-phase superposition, causing sound energy to be directionally concentrated towards the ear canal; however, the far-field sound waves, lacking equal enhancement, fail to form an equal concentration of sound energy. This further amplifies the sound pressure difference between the near and far fields, resulting in a significant relative attenuation of far-field leakage compared to the near-field perceived sound, greatly improving the privacy protection of users during calls in quiet environments.

[0019] 4. Compact structure, easy for industrial production This dual-unit sound leakage prevention acoustic structure is based entirely on improvements in physical shape and construction. The overall solution has high internal space utilization, a compact structure, and can perfectly adapt to the slim design requirements of existing smart glasses temples without thickening the temples. It also has stable manufacturing process, is easy to mass-produce and assemble, and combines high performance and high reliability. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments and the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a cross-sectional schematic diagram of the dual-unit sound leakage prevention acoustic structure of Embodiment 1 of this application; Figure 2 This is a bottom view schematic diagram of the dual-unit sound leakage prevention acoustic structure of Embodiment 1 of this application; Figure 3 This is a schematic diagram comparing the frequency response curves of this application with those of a traditional dual-aperture design; Figure 4 This is a schematic diagram comparing the leakage of this application with that of a traditional dual-sound-inlet port at a 90-degree position; Figure 5 This is a schematic diagram comparing the leakage of this application with that of a traditional dual-sound-inlet port at the 0-degree position; Figure 6 Frequency response curves of the two front sound holes when they are working independently for this application were tested separately. Figure 7 This is a phase difference test curve of the sound waves emitted from the two front sound holes of this application; Figure 8 This is a side view of the dual-unit sound leakage prevention acoustic structure of Embodiment 2 of this application; Figure 9 This is a cross-sectional schematic diagram of the dual-unit sound leakage prevention acoustic structure of Embodiment 1 of this application.

[0022] The reference numerals in the attached drawings are explained as follows: 10-temple; 1-first speaker; 2-second speaker; 3-first front sound outlet; 4-second front sound outlet; 5-first rear sound outlet; 6-second rear sound outlet. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present application.

[0024] The terms "first," "second," "third," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0025] The following detailed descriptions will be provided through specific embodiments.

[0026] Example 1 refer to Figure 1 and Figure 2 Embodiment 1 of this application provides a dual-unit sound leakage prevention acoustic structure, which is mainly used in head-mounted devices such as eyeglasses. Figure 1 and Figure 2 As shown, the dual-unit sound leakage prevention acoustic structure of this application includes a temple 10 of eyeglasses. A first speaker 1 and a second speaker 2 are disposed within the cavity space inside the temple 10. A first front sound outlet 3, acoustically coupled to the first speaker 1, and a second front sound outlet 4, acoustically coupled to the second speaker 2, are provided on the side of the temple 10 facing the user's ear canal (i.e., the inner wall). The opening areas of the first front sound outlet 3 and the second front sound outlet 4 are different, and when the temple 10 is worn on the user's head, the distances from the first front sound outlet 3 and the second front sound outlet 4 to the user's ear canal are different.

[0027] Here, the glasses 10 refers to a wearable device with temples, which may take the form of smart audio glasses, AR / VR glasses, or conventional audiovisual aids. The first speaker 1 and the second speaker 2 refer to miniature electroacoustic transducers used to convert electrical signals into acoustic signals, and their specific types include, but are not limited to, dynamic loudspeakers or microelectromechanical system (MEMS) loudspeakers.

[0028] In some optional embodiments, the area difference between the first front sound outlet 3 and the second front sound outlet 4 creates an inherent phase difference between the first sound wave emitted by the first speaker 1 through the first front sound outlet 3 and the second sound wave emitted by the second speaker 2 through the second front sound outlet 4. Simultaneously, the distance difference between the first and second front sound outlets 3 and 4 to the user's ear canal constitutes a physical path difference to compensate for the inherent phase difference, thereby creating a near-field acoustic in-phase superposition zone at the user's ear canal. By rationally designing the area ratio and spacing of the two sound outlets, the sound waves emitted by the two speakers can have approximately the same phase when reaching the user's ear canal, thus achieving a superposition enhancement of sound pressure. This near-field in-phase superposition effect can significantly improve the user's hearing clarity and loudness perception while wearing the device, ensuring sufficient sound energy at the ear canal even with low speaker unit output power, which helps reduce power consumption and extend the device's battery life. In the far field, however, the distance difference between the first and second front sound outlets to the far-field measuring point is extremely small, failing to create a near-field acoustic in-phase superposition zone and thus preventing the acquisition of in-phase superposition gain. This effectively amplifies the sound pressure difference between the near and far fields. In other words, the leakage in the far field is significantly reduced, thereby greatly improving the privacy protection of users during calls in quiet environments.

[0029] In some optional implementations, the area difference between the first front sound outlet 3 and the second front sound outlet 4 causes the synthesized frequency response curve to form a main peak near 4.5kHz and a secondary peak near 6kHz, with the sound pressure level of the secondary peak being lower than that of the main peak. By appropriately setting the area difference between the two front sound outlets, the shape of the synthesized frequency response curve can be effectively controlled. The main peak formed near 4.5kHz corresponds to the frequency band most sensitive to human hearing, effectively improving speech clarity and intelligibility; while the secondary peak formed near 6kHz supplements high-frequency details, and its sound pressure level is lower than that of the main peak, avoiding auditory fatigue caused by excessively bright high frequencies. This dual-peak structure's frequency response characteristics help to obtain a more natural and balanced listening experience while ensuring listening clarity.

[0030] In some optional embodiments, the temple 10, on the side facing away from the user's ear canal (i.e., the outer wall), also has a first rear sound outlet 5 acoustically coupled to the first speaker 1 and a second rear sound outlet 6 acoustically coupled to the second speaker 2. The first and second rear sound outlets 5 and 6 provide an effective acoustic pressure relief channel for the rear cavity of the speaker diaphragm. This arrangement not only improves the low-frequency response characteristics of the speaker and extends the low-frequency depth, but also balances the air pressure on both sides of the diaphragm, preventing nonlinear distortion caused by excessive pressure difference, thus ensuring the purity of sound quality during high-volume playback. Furthermore, since the sound waves on both sides of the speaker diaphragm are physically naturally out of phase (i.e., the sound waves emitted from the front and rear sound outlets are strictly opposite or nearly opposite in phase), the back-facing sound waves emitted from the first and second rear sound outlets 5 and 6 can interfere destructively with the sound waves emitted from the front sound outlet in the far-field region, thus helping to suppress far-field sound leakage and further enhancing the overall sound leakage prevention effect.

[0031] In some optional embodiments, the cavity space between the first loudspeaker 1 and the first front sound outlet 3 forms a first front acoustic cavity, and the first front acoustic cavity, the first loudspeaker 1, and the first front sound outlet 3 constitute a first acoustic resonant system; the cavity space between the second loudspeaker 2 and the second front sound outlet 4 forms a second front acoustic cavity, and the second front acoustic cavity, the second loudspeaker 2, and the second front sound outlet 4 constitute a second acoustic resonant system; the difference in the opening area between the first front sound outlet 3 and the second front sound outlet 4 makes the acoustic resonant frequencies of the first acoustic resonant system and the second acoustic resonant system different, so as to achieve natural physical frequency division between the first front sound outlet and the second front sound outlet.

[0032] In some alternative implementations, the area of ​​the first front sound outlet 3 is larger than that of the second front sound outlet 4. The loudness contribution of the first front sound outlet 3 is mainly above 5000Hz, while the loudness contribution of the second front sound outlet 4 is mainly between 3000Hz and 5000Hz. By setting the two front sound outlets to different areas, the two speaker units can undertake different loudness contributions in the high-frequency and low-frequency ranges respectively. The larger first front sound outlet 3 has a higher resonant frequency, which is beneficial for the radiation of high-frequency sound waves, so its loudness contribution is mainly concentrated in the high-frequency range above 5000Hz; while the smaller second front sound outlet 4 has a lower resonant frequency, which has a certain suppression effect on high frequencies, and its loudness contribution is mainly concentrated in the mid-frequency range of 3000Hz to 5000Hz. This configuration of high and mid-frequency division of labor allows the two speakers to work complementaryly, obtaining a flatter composite frequency response curve over a wider frequency range, avoiding the frequency response peaks and valleys that may occur when a single speaker operates across the entire frequency band. It should be noted that the aforementioned 5000Hz dividing frequency is an empirical value based on typical design parameters. In actual product design, this dividing frequency may deviate due to differences in the inherent frequency response characteristics of the speaker unit, the specific shape of the sound hole, and the internal cavity volume of the temple. Those skilled in the art can make adaptive adjustments to the sound hole area ratio and front cavity volume based on actual measurement results to obtain the optimal synthesized frequency response curve.

[0033] Here, the first acoustic resonant system, consisting of the first loudspeaker 1, its first front acoustic cavity, and the first front sound outlet 3, can be expressed by the following formula:

[0034] Where c is the speed of sound in air (usually taken as 340m / s), S is the cross-sectional area of ​​the first front sound hole 3, V is the volume of the first front sound cavity (i.e. the cavity between the front of the diaphragm of the first loudspeaker 1 and the first front sound hole 3), and L is the equivalent length of the first front sound hole 3.

[0035] The equivalent length L of the first front sound outlet 3 is determined by the thickness l of the first sound outlet and its equivalent radius r, and its empirical formula is L = l + 1.5r. When the first front sound outlet 3 is rectangular, its equivalent radius r can be calculated as follows: First, measure the length and width of the first front sound outlet 3, calculate its cross-sectional area S (i.e., length × width), and then convert this area S into a circle of equal area. The radius of this equivalent circle is the equivalent radius r of the first front sound outlet 3, i.e., r = (S / π). 1 / 2 .

[0036] Based on the above formula, it can be deduced that, under the premise that the thickness l of the first front sound outlet 3 and the volume V of the first front acoustic cavity are basically fixed, the larger the cross-sectional area S of the first front sound outlet 3, the larger the equivalent radius r, and thus the larger the equivalent length L. The increase of S has a tendency to increase the resonant frequency at the molecular level. In the actual cavity acoustic coupling model, a larger opening area often causes the main resonant frequency of the acoustic resonant system to shift to the mid-to-high frequency range (corresponding to the fact that the first front sound outlet 3 in this embodiment is mainly responsible for the high frequency range above 5000Hz).

[0037] Similarly, the second acoustic resonant system, consisting of the second loudspeaker 2, its second front acoustic cavity, and the second front sound outlet 4, uses the same formula for calculating its resonant frequency. Since the physical cavity volume V and the sound outlet thickness l of the second front acoustic cavity are essentially the same as those of the first acoustic resonant system, the difference lies in the smaller cross-sectional area S of the second front sound outlet 4. Calculations show that the smaller cross-sectional area S corresponds to a smaller equivalent radius r and a specific acoustic impedance, causing the acoustic resonant frequency of the second acoustic resonant system to primarily fall in the mid-frequency range of 3000Hz to 5000Hz. It is precisely because of the different cross-sectional areas of the first front sound outlet 3 and the second front sound outlet 4 in terms of geometry that the two acoustic resonant systems have different inherent resonant frequencies. Acoustically, they work together to ultimately form a main peak of 4.5kHz and a secondary peak of 6kHz, achieving natural physical crossover without the need for EQ adjustment.

[0038] In some optional embodiments, the distance difference between the first front sound outlet 3 and the second front sound outlet 4 and the user's ear canal can be controlled between 0.8 and 1.2 cm, for example, 1.0 cm. Setting the distance difference between the two sound outlets and the ear canal within the range of 0.8-1.2 cm provides a suitable physical path difference for the superposition of the two sound waves at the ear canal position. The sound wave propagation time difference corresponding to this distance difference matches the inherent phase difference between the two speakers due to the difference in the area of ​​the sound outlets, thereby achieving near-field in-phase superposition. If the distance difference is too large, it may lead to over-phase compensation and phase deviation; if the distance difference is too small, it may not be able to fully compensate for the inherent phase difference. Therefore, controlling the distance difference within the above range is beneficial for obtaining the optimal near-field superposition effect.

[0039] In some optional embodiments, an acoustic isolation partition is provided between the first speaker 1 and the second speaker 2. By providing an acoustic isolation partition between the two speakers, acoustic crosstalk between the two speakers in the internal cavity of the temple can be effectively prevented. The isolation partition divides the interior of the temple into two independent acoustic chambers, ensuring that the front and rear sound fields of each speaker do not interfere with each other. This helps maintain the independence and purity of the two channel signals and avoids sound image blurring and positioning inaccuracy caused by cavity coupling.

[0040] In some optional embodiments, the area ratio of the first front sound outlet 3 to the second front sound outlet 4 is between 1.5 and 2.5. Controlling the area ratio of the two front sound outlets within this range ensures sufficient acoustic characteristic difference between the two speaker units while preventing excessive area difference from causing one speaker to have excessively low sound radiation efficiency in a specific frequency band. Within this ratio range, the required inherent phase difference can be generated, while ensuring reasonable sound output efficiency for both speakers in their respective operating frequency bands, which is beneficial for achieving sound pressure level balance across the entire frequency band.

[0041] In some alternative implementations, the first loudspeaker 1 and the second loudspeaker 2 have substantially the same structure and acoustic characteristics. By selecting two loudspeaker units with essentially identical structures and acoustic characteristics, the matching difficulties in the design and production process can be simplified, reducing manufacturing costs. The consistency of the two loudspeaker units also makes the overall acoustic performance more controllable and predictable, which is beneficial for ensuring product consistency and yield. In terms of driving, identical loudspeaker units also facilitate the use of identical power amplification and signal processing circuits, simplifying system design.

[0042] In some alternative embodiments, the first speaker 1 and the second speaker 2 are arranged at intervals along the length of the temple 10. This helps to make full use of the narrow space of the temple and avoids the speakers occupying too much space in the width or thickness direction of the temple. This arrangement also facilitates the opening of front sound holes at different positions on the inner sidewall of the temple, thereby realizing the distance difference between the two sound holes and the ear canal, creating physical conditions for near-field in-phase superposition.

[0043] refer to Figure 3 , Figure 3 This is a schematic diagram comparing the frequency response curves of this application with those of a traditional dual-aperture acoustic chamber. From... Figure 3As can be seen, compared with the traditional dual-port structure (where the opening areas of the two ports are the same, referred to as "same port"), the dual-unit sound leakage prevention acoustic structure of this application (where the opening areas of the two ports are different, referred to as "different port") has better frequency response characteristics across the entire frequency range. Specifically, the traditional structure (same port) has only a single frequency response peak, and this peak is located near the 6kHz frequency band, where the sound pressure level reaches its highest. In contrast, the synthesized frequency response curve of the dual-unit sound leakage prevention acoustic structure (different port) of this application forms a main peak near the 4.5kHz frequency band and a secondary peak near the 6kHz frequency band, with the sound pressure level of the main peak being significantly higher than that of the secondary peak. Specifically, in the mid-to-high frequency range above 5kHz, the sound pressure level of this solution is significantly lower than that of the traditional structure, effectively avoiding the harsh listening experience caused by the high resonance peak at the 6kHz frequency band in the traditional single-peak structure. A comparison of the frequency response characteristics of the two solutions shows that the solution rationally redistributes the high-frequency resonant energy through a physical crossover structure. This not only achieves a smoother and wider frequency response curve, but also significantly improves the loudness of the important 4kHz vocal frequency band while naturally suppressing the high frequencies near 6kHz, thus optimizing the user's mid-to-high frequency listening clarity and sound quality purity.

[0044] refer to Figure 4 and Figure 5 , Figure 4 and Figure 5 These are schematic diagrams comparing the leakage of this application with that of a traditional dual-inlet design (where both inlets have the same opening area) at 90 degrees and 0 degrees. It should be noted that the above leakage test uses the difference method: subtracting the leakage sound field at a certain distance (e.g., 20cm) from the in-ear sound field. Under this testing method, the vertical axis in the graph represents this sound pressure level difference. The higher the value of the vertical axis, the smaller the leakage sound pressure level outside the ear relative to the dominant volume inside the ear, meaning a better sound leakage prevention effect. Combined with... Figure 4 (90-degree direction, i.e., perpendicular to the ear canal, taking 20cm as an example) and Figure 5 The curves (at 0 degrees, i.e., directly in front of the user's head) show that, within the test frequency band of 1000Hz to 10000Hz, the difference curves of this patented design (with different apertures) are significantly higher than those of the traditional design with the same aperture in most frequency bands. This comparison fully demonstrates that, because this application cannot obtain near-field in-phase superposition gain in the far field, the sound energy in the far field region is significantly suppressed. Therefore, regardless of whether it is at 0 degrees or 90 degrees, this patented design can achieve lower and less far-field sound leakage, thereby effectively protecting the user's call privacy in practical applications and avoiding sound interference to surrounding people.

[0045] refer to Figure 6 , Figure 6 Frequency response curves for each of the two front sound holes were tested separately when operating independently, for this application. Figure 6It can be seen that when the first front exit hole 3 (with a larger area) operates alone, its frequency response curve has a higher sound pressure level in the high-frequency range (above 5000Hz); while when the second front exit hole 4 (with a smaller area) operates alone, its frequency response curve has a higher sound pressure level in the mid-low frequency range (below 5000Hz). When both front exit holes operate simultaneously, the loudness response above 5000Hz is dominated by the first front exit hole 3, while the loudness response below 5000Hz is dominated by the second front exit hole 4. After the two are combined, a flatter and more balanced frequency response characteristic is obtained across the entire frequency band, verifying the complementary relationship between the two exit holes in terms of frequency response. In this test, operating alone means that only the corresponding speaker is driven, the other speaker is not given an electrical signal, and the other front exit hole remains open (i.e., not blocked) to simulate the acoustic environment under actual use conditions.

[0046] refer to Figure 7 , Figure 7 This is a phase difference test curve of the sound waves emitted from the two front sound holes of this application. From... Figure 7 It can be seen that within the important mid-to-high frequency band of 4kHz to 6kHz, there is a significant inherent phase difference between the sound waves emitted from the two front sound holes. This phase difference arises from the acoustic differences caused by the different resonant frequencies formed by the first and second front sound holes and the front cavity. Combined with the aforementioned physical sound path difference of approximately 1cm from the first and second front sound holes to the user's ear canal, this relatively large inherent phase difference, under the compensation effect of the physical sound path difference, ultimately forms a near-field acoustic in-phase superposition region in the user's ear canal.

[0047] Furthermore, through acoustic theoretical calculations combined with measured data, it can be concluded that in the near field (e.g., the ear canal), the aforementioned 1cm physical path difference results in approximately 53° of phase lag for a 5kHz sound wave in air. This approximately 53° phase lag is precisely what allows the sound wave to... Figure 7 The inherent phase difference between the two front sound holes cancels each other out, achieving a near-phase-deviation-free in-phase superposition effect in the near field, maximizing loudness in the ear canal. However, in the far field, the distance difference from the far-field measuring point to the two front sound holes becomes extremely small, making the near-field compensation effect impossible. Therefore, the inherent phase difference between the two emitted sound waves plays a dominant role in the far field, producing an anti-phase cancellation effect, thus significantly suppressing far-field leakage. Test data also shows that this phase difference compensation and cancellation mechanism is particularly significant below 5kHz; while above 5kHz, due to the shorter wavelength of the sound waves and the difference in sensitivity of phase changes to distance, the leakage rate changes relatively smoothly.

[0048]

Example 2

[0049]

Example 3

[0050] The technical solution of this application has been described in detail above through specific embodiments. In the above embodiments, the descriptions of each embodiment have their own emphasis, and for parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0051] It should be understood that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some of the technical features; however, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and protection scope of the technical solutions of the embodiments of this application.

Claims

1. A dual-unit sound leakage prevention acoustic structure, including the temples of eyeglasses, characterized in that: The temple of the mirror is equipped with a first speaker and a second speaker. The temple of the glasses has a first front sound outlet that is acoustically coupled to the first speaker and a second front sound outlet that is acoustically coupled to the second speaker on the side facing the user's ear canal. The opening areas of the first front sound outlet and the second front sound outlet are different, and when the temples are worn on the user's head, the distances from the first front sound outlet and the second front sound outlet to the user's ear canal are different.

2. The dual-unit sound leakage prevention acoustic structure according to claim 1, characterized in that: The area difference between the first front sound outlet and the second front sound outlet causes an inherent phase difference between the first sound wave emitted by the first speaker through the first front sound outlet and the second sound wave emitted by the second speaker through the second front sound outlet. The distance difference between the first front sound outlet and the second front sound outlet to the user's ear canal constitutes a physical sound path difference that compensates for the inherent phase difference, thereby forming a near-field acoustic in-phase superposition region at the user's ear canal position.

3. The dual-unit sound leakage prevention acoustic structure according to claim 1, characterized in that: The area difference between the first and second front sound holes causes their combined frequency response curves to form a main peak near the 4.5kHz frequency band and a secondary peak near the 6kHz frequency band, with the sound pressure level of the secondary peak being lower than that of the main peak.

4. The dual-unit sound leakage prevention acoustic structure according to claim 1, characterized in that: The temple of the glasses is provided with a first rear sound outlet that is acoustically coupled to the first speaker and a second rear sound outlet that is acoustically coupled to the second speaker on the side opposite to the user's ear canal.

5. The dual-unit sound leakage prevention acoustic structure according to claim 1, characterized in that: A first front acoustic cavity is provided between the first loudspeaker and the first front sound outlet, and the first front acoustic cavity, the first loudspeaker and the first front sound outlet constitute a first acoustic resonant system. The second speaker and the second front sound hole have a second front acoustic cavity, and the second front acoustic cavity, the second speaker and the second front sound hole constitute a second acoustic resonance system; The difference in opening area between the first front sound outlet and the second front sound outlet results in different acoustic resonant frequencies between the first acoustic resonant system and the second acoustic resonant system, thereby achieving natural physical frequency division between the first front sound outlet and the second front sound outlet.

6. The dual-unit sound leakage prevention acoustic structure according to claim 5, characterized in that: The area of ​​the first front sound outlet is larger than that of the second front sound outlet; in the frequency band above 5000Hz, the loudness contribution of the first front sound outlet is greater than that of the second front sound outlet; in the frequency band from 3000Hz to 5000Hz, the loudness contribution of the second front sound outlet is greater than that of the first front sound outlet.

7. The dual-unit sound leakage prevention acoustic structure according to claim 1, characterized in that: The difference in distance between the first front sound outlet and the second front sound outlet and the user's ear canal is between 0.8 and 1.2 centimeters; The area ratio of the first front sound outlet to the second front sound outlet is between 1.5 and 2.

5.

8. The dual-unit sound leakage prevention acoustic structure according to claim 1, characterized in that: An acoustic isolation partition is provided between the first speaker and the second speaker.

9. The dual-unit sound leakage prevention acoustic structure according to claim 1, characterized in that: The first speaker and the second speaker are arranged at intervals along the length of the temple; or, the first speaker and the second speaker are arranged in a staggered manner relative to the user's ear canal, one inside and one outside.

10. Eyeglasses comprising a dual-unit sound leakage prevention acoustic structure as described in any one of claims 1-9.

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