KR20230165895A - Air-Pulse Generating Device with Efficient Propagation - Google Patents

Abstract

The air pulse generating device includes a film structure. The film structure is operated such that the air pulse generating device generates a plurality of air pulses. A horn-shaped outlet is formed inside the air pulse generating device, and a plurality of air pulses are propagated through the horn-shaped outlet.

Description

Air-Pulse Generating Device with Efficient Propagation}

The present invention relates to an air-pulse generator, and more specifically to an air-pulse generator that can efficiently propagate waves.

Speaker drivers and rear enclosures are two major design challenges in the speaker industry. It is difficult for existing speakers to cover the entire audio frequency band, for example from 20Hz to 20KHz. To produce high-fidelity sound at sufficiently high sound pressure levels (SPL), both the radiating/moving surface for the existing speaker and the volume/size of the rear enclosure must be sufficiently large.

Therefore, how to design compact sound generating devices while overcoming the design challenges faced by conventional speakers is an important goal in this field.

Therefore, the main purpose of the present invention is to provide an air pulse generating device to improve the shortcomings of the prior art.

One embodiment of the present disclosure provides an air pulse generating device including a film structure; The film structure is actuated so that the air pulse generating device generates a plurality of air pulses; A horn-shaped outlet is formed in the air pulse generating device, and a plurality of air pulses are propagated through the horn-shaped outlet.

One embodiment of the present disclosure includes a subassembly disposed or to be disposed within an air pulse generating device, the subassembly including a conduit formed within the subassembly, and the conduit including a passageway and a horn-shaped outlet. and the subassembly is or will be assembled with a device comprising the film structure.

These and other objects of the present invention will no doubt become apparent to those skilled in the art after reading the following detailed description of the preferred embodiments illustrated in the various drawings and figures.

1 is a schematic diagram of an air pulse generator according to an embodiment of the present invention.
Figure 2 illustrates the waveforms of a demodulation drive signal and a modulation drive signal according to an embodiment of the present invention.
Figure 3 illustrates simulated results corresponding to the device of Figure 1.
Figure 4 plots the simulated frequency response of the sound pressure level of the APG device of Figure 1.
Figure 5 illustrates simulated results corresponding to the device of Figure 1.
Figure 6 illustrates simulated results corresponding to the device of Figure 1.
Figure 7 is a schematic diagram of an air pulse generator according to an embodiment of the present invention.
Figure 8 is a schematic diagram of an air pulse generating device according to an embodiment of the present invention.
Figure 9 illustrates the frequency response of the energy transfer rate of the device of Figure 1.
Figure 10 illustrates the frequency response of the energy transfer rate of the device of Figure 8.
Figure 11 shows the process of the manufacturing method for the device of Figure 8.
Figure 12 is a schematic diagram of an air pulse generating device according to an embodiment of the present invention.
Figure 13 illustrates a driving signal wiring method according to embodiments of the present invention.
Figure 14 illustrates SPL measurement results for the frequencies of the device of Figure 12.
Figure 15 illustrates SPL measurement results for peak-to-peak voltage for the device of Figure 12.
Figure 16 is a schematic diagram of an air pulse generator according to an embodiment of the present invention.
Figure 17 is a schematic diagram of an air pulse generator according to an embodiment of the present invention.
Figure 18 illustrates a snapshot of a finite element method (FEM) simulated pressure profile of a device similar to that of Figure 17.
Figure 19 illustrates the ear coupler SPL measurement results for the frequencies of the device of Figure 17.
Figure 20 is a schematic diagram of an air pulse generating device according to an embodiment of the present invention.
Figure 21 is a schematic diagram of an air pulse generating device according to an embodiment of the present invention.
Figure 22 is a schematic diagram of an air pulse generating device according to an embodiment of the present invention.
Figure 23 is a schematic diagram of an air pulse generating device according to an embodiment of the present invention.
Figure 24 is a schematic diagram of an air pulse generator according to an embodiment of the present invention.
Figure 25 demonstrates an example of timing alignment of virtual valve opening according to an embodiment of the present invention.
Figure 26 is a schematic diagram of an air pulse generating device according to an embodiment of the present invention.
Figure 27 shows an example of timing alignment of virtual valve opening according to an embodiment of the present invention.
Figure 28 illustrates full cycle pulses within one operating cycle with different degrees of asymmetry.
Figure 29 is a schematic top view of an air pulse generating device according to an embodiment of the present invention.
Figure 30 is a schematic top view of the air pulse generating device of Figure 29.
Figure 31 is a plan view of an air pulse generator according to an embodiment of the present invention.
FIG. 32 illustrates waveforms of two sets of (demodulated) modulated drive signals for the air pulse generator of FIG. 31.
Figure 33 is a plan view of an air pulse generator according to an embodiment of the present invention.
Figure 34 illustrates a system view of the functionality of each component and the corresponding frequency domain effects.

A fundamental aspect of the present invention relates to an air pulse generating device, and more particularly to an air pulse generating device comprising a modulating means and a demodulating means, the modulating means being an ultrasonic air pressure wave/change having a frequency f _UC . pressure wave/variation (UAW), and the amplitude of UAW is modulated according to the input audio signal (S _IN ), which is an electrical (analog or digital) representation of a sound signal (SS). This amplitude modulated ultrasonic air pressure wave/variation (AMUAW) is then synchronously demodulated by demodulating means such that the spectral components embedded in the AMUAW are shifted by ± n · f _UC , where n is a positive is the integer of As a result of this synchronous demodulation, the spectral components of the AMUAW corresponding to the sound signal (SS) are partially transmitted to the baseband and the resulting audible sound signal (SS) is reproduced. Here, the amplitude modulated ultrasonic barometric pressure wave/variation (AMUAW) may correspond to a carrier component having an ultrasonic carrier frequency f _UC and a modulation component corresponding to the input audio signal (S _IN ).

1 shows a schematic diagram of an air-pulse generator (APG) device 100 according to one embodiment of the present invention. The device 100 may be applied as a sound generating device that generates acoustic sound according to the input (audio) signal (S _IN ), but is not limited to this.

Device 100 includes a device layer 12 and a chamber definition layer 11. Device layer 12 includes support structures 123R, 123L that support thin film layers etched into walls 124L, 124R and flaps 101, 103, 105, 107. In one embodiment, device layer 12 may be fabricated by a Micro Electro Mechanical Systems (MEMS) manufacturing process using, for example, a 250-500 μM thick Si substrate, which is etched to produce 123L/R and 124R/L. can be formed. In one embodiment, on top of this Si substrate, a thin layer, typically 3-6 μM thick, made of silicon on insulator (SOI) or POLY on insulator (POI) layer is etched to form flaps 101, 103. , 105, 107).

The chamber defining layer 11 (which may also be considered/named a “cap” structure) includes a pair of chamber sidewalls 110R, 110L and a chamber ceiling 117. In one embodiment, chamber defining layer (or cap structure) 11 may be manufactured using MEMS manufacturing techniques. A resonance chamber 115 is defined between the chamber defining layer 11 and the device layer 12.

In other words, the device 100 can be viewed as comprising a film structure 10 and a cap structure 11 with a chamber 115 formed therebetween. Film structure 10 can be viewed as including a modulation portion 104 and a demodulation portion 102. The modulation portion 104 including the (modulation) flaps 105 and 107 is configured to be actuated to form an ultrasonic air/acoustic wave within the chamber 115, and is configured to actuate the air/acoustic wave. Waves can be viewed as a type of change in air pressure that changes both temporally and spatially. In one embodiment, the ultrasonic air/acoustic wave or air pressure change may be an amplitude double-sideband suppress carrier (DSB-SC) modulated air/acoustic wave with an ultrasonic carrier frequency f _UC . The ultrasonic carrier frequency f _UC may for example range from 160 KHz to 192 KHz, which is much greater than the maximum frequency of sound audible to humans.

The terms air wave and acoustic wave will be used interchangeably below.

The demodulation section 102, comprising (demodulation) flaps 101, 103, is configured to operate synchronously with the modulation section 102, so that the spectrum of the DSB-SC modulated acoustic wave generated by the modulation section 104 The component is shifted _by ± n The baseband frequency component of the plurality of air pulses (generated by the demodulation portion 102 according to the wave) is or corresponds/related to the input (audio) signal (S _IN ), wherein the low frequency component of the plurality of air pulses is in the audible spectrum. Refers to the frequency component of a plurality of air pulses (e.g., below 20 or 30 KHz). Here, baseband may generally refer to the audible spectrum, but is not limited thereto.

In other words, in a sound generation application, the modulation section 104 may be operated to form air waves modulated according to the input audio signal S _IN , and the demodulation section 102 may operate in synchronization with the modulation section 104. and generate a plurality of air pulses having a low-frequency component as (or corresponding to/related to) the input audio signal (S _IN ). For sound generation applications, f _UC is f _UC ≥ 96KHz Much higher than the highest frequencies normally audible to humans, such as 5 and the human ear system such as the external auditory canal, eardrum, malleus, incus, stapes, etc.), all that the listener perceives is the audible sound or music represented by the input audio signal (S _IN ).

Illustratively, Figure 34 conceptually/schematically shows the effect of the (de)modulation operation by showing the frequency spectrum of the signal before and after the (de)modulation operation. In Figure 34, the modulation operation is an amplitude modulated ultrasonic acoustic/air wave (UAW) with a spectrum shown as W( f ) depending on the input audio signal (S _IN ), which is an electrical (analog or digital) representation of the sound signal (SS). ) is created. The spectrum of S _IN /SS is expressed as S( f ) in Figure 34. Synchronous demodulation operation to generate an ultrasonic pulse array (UPA) (containing multiple pulses) with the spectrum illustrated by Z ( f ) is a method of generating an ultrasonic acoustic/air wave (UAW). It can be viewed as shifting (including steps) the spectral component by ± n × f _UC (n is an integer), and the spectral component of the ultrasonic air wave (UAW) corresponding to the sound signal (SS) is partially is transmitted to the baseband. Therefore, as can be seen from Z( f ), the baseband component of the ultrasonic pulse array (UPA) is significant compared to the amplitude modulated UAW W( f ). Ultrasonic pulse array (UPA) propagates toward the surroundings. Through the natural/physical environment and the inherent low-pass filtering effect of the human auditory system, the spectrum Y( f ) corresponding to the resulting sound signal (SS) can be reproduced.

Unlike conventional DSB-SC amplitude modulation, which uses a sinusoidal carrier, W ( f ) is measured at ±3× f _UC , ±5× f _UC and the higher order harmonics of f _UC (not shown in Figure 34) Note that it has components of This is because the carrier wave of the modulation of the present invention is not a pure sine wave.

Referring back to FIG. 1 , in an embodiment of a synchronous demodulation operation, the demodulation portion 102 may be actuated to form an opening 112 at a time and location corresponding to/aligned with the peak(s) of the modulated air wave. . In other words, when the modulated air wave reaches a peak at the location of the aperture 112, the demodulation portion 102 may be activated so that the aperture 112 also reaches the peak.

In the embodiment shown in Figure 1, demodulating portion 102 defines an opening 112 at a surface-to-surface, or central location between sidewalls 110L and 110R having 111L to 111R, with (substantially) between them. There is a spacing of λ _UC , meaning that the flaps 101, 103 are (substantially) λ _UC /2 away from the sidewalls 110L, 110R or from the sidewall surfaces 111L, 111R, where λ _UC is the ultrasound It represents the wavelength corresponding to the carrier frequency f _UC , that is, using C, the speed of sound, λ _UC = C/ f _UC .

In one embodiment, demodulation portion 102 may be actuated to form opening 112 with a valve opening rate synchronized to/with the ultrasonic carrier frequency f _UC . In the present invention, the valve opening rate synchronized to/with the ultrasonic carrier frequency f _UC generally refers to the valve opening rate being the ultrasonic carrier frequency f _UC multiplied by a rational number, i.e. f _UC ×( N / M ), where N and M represents an integer. In one embodiment, the valve opening rate (of opening 112) may be the ultrasonic carrier frequency f _UC . For example, the valve/opening 112 may be opened per operating cycle T _CY , where the operating cycle T _CY is the reciprocal of the ultrasonic carrier frequency f _UC , i.e. T _CY =1/ f _UC .

In the present invention, the (demodulation) modulation section 102/104 is also used to denote a pair of (demodulation) modulation flaps. Additionally, the demodulation portion (or flap pair) 102 forming the opening 112 performs (periodically) an open-and-close movement in accordance with a specific valve/demodulation drive signal and forms the opening 112. It can be considered a virtual valve.

λ_UC = C/f _UC이다. 또한 도 1에 도시된 실시예에서, 변조 플랩(105/107)의 자유 단부는 측벽(110L/110R)에 의해 배치된다.In one embodiment, the modulation portion 104 is configured to achieve mode-2 (or second harmonic) resonance within the resonant chamber 115, such as pressure profile P104 and airflow profile U104 illustrated in FIG. Alternatively, a standing wave may be substantially generated. In this regard, the spacing between the sidewall surfaces 111L, 111R essentially defines the total wavelength λ _UC corresponding to the ultrasonic carrier frequency f _UC , i.e. W115

λ _UC = C/ f _UC . Also in the embodiment shown in Figure 1, the free ends of the modulating flaps 105/107 are disposed by side walls 110L/110R.

Mutual modulation (or cross-coupling) may occur between the modulation that generates the modulated air wave and the demodulation that forms the opening 112, which may result in deterioration of sound quality. In order to improve sound quality, it is desirable to minimize intermodulation (or cross-coupling). To achieve this (i.e. to minimize cross-coupling between modulation and demodulation), the modulation flaps 105, 107 are driven with common mode movement and the demodulation flaps 101, 103 are driven with differential mode movement. It is driven to have differential-mode movement. Modulating flaps 105, 107 with common mode movement means that flaps 105, 107 are actuated/driven simultaneously such that they move towards the same direction. Demodulating flaps 101 and 103 with differential mode movement means that the flaps 101 and 103 are actuated simultaneously to move towards opposite directions. Also in one embodiment, the flaps 101 and 103 may be actuated to move in opposite directions with (substantially) the same displacement/magnitude.

λ_{D_V}/2가 되도록 밸브 작동/구동 주파수 f _{D_V}(밸브/복조-구동 신호에 대응)에서 작동해야 하며, 여기서 λ_{D_V} = C/f _{D_V}이고, 밸브 작동/구동 주파수는 초음파 반송파 주파수 f _UC의 절반이어야 하며 즉, f _{D_V} = f _UC/2이다.The demodulating portion 102 may generate mode-1 (or first harmonic) signals within the resonant chamber 115, such as the pressure profile P102 and the airflow profile U102 formed by the demodulating portion 102 illustrated in FIG. Resonance (or standing waves) can be substantially generated. Therefore, the demodulation section 102 is W115

It must be operated at a valve operating/driving frequency f _{D_V} (corresponding to the valve/demodulation-actuating signal) such that λ _{D_V} /2, where λ _{D_V} = C/ f _{D_V} , and the valve operating/driving frequency is equal to the ultrasonic carrier frequency f _UC. It should be half, that is, f _{D_V} = f _UC /2.

Common mode shift and differential mode shift can be driven by a (demodulated) modulation drive signal. Figure 2 illustrates the waveforms of the demodulation drive signals (S101, S103) and the modulation drive signal (SM). The modulation drive signal (SM) is used to drive the modulation flaps (105, 107). The demodulation drive signals (or valve drive signals) S101 and S103 are used to drive the demodulation flaps 101 and 103, respectively.

In one embodiment, the modulation driving signal (SM) can be viewed as a pulse amplitude modulation (PAM) signal modulated according to the input audio signal (S _IN ). Additionally, unlike conventional PAM signals, the polarity (relative to constant voltage) of signal SM is toggled within one operating cycle T _CY . Typically, the modulation-drive signal (SM) contains pulses with alternating polarities (relative to a constant voltage), and the envelope/amplitude of the pulses is determined by the alternative current (AC) of the input audio signal (S _IN ). ) is (substantially) identical to or corresponds to/proportional to the component. In other words, the modulation drive signal SM can be viewed as including a pulse amplitude modulated signal or PAM modulated pulses with alternating polarity with respect to a constant voltage. In the embodiment shown in Figure 2, the toggling rate of the modulation drive signal SM is 2× f _UC , which means that the polarity of the pulses in the modulation drive signal SM is _two It means that the number is alternated/toggled.

The demodulated drive signals (S101, S103) include two drive pulses of equal amplitude (for constant/average voltage) but opposite polarity. In other words, at a certain time, S101 includes a first pulse with a first polarity (for a constant/average voltage), S103 includes a second pulse with a second polarity (for a constant/average voltage), and , the first polarity is opposite to the second polarity. As shown in Figure 2, the toggling ratio of the demodulation drive signal (S101/S103) is f _UC , which means that the polarity of the pulses in the demodulation drive signal (S101/S103) alternates once in one operation cycle T _CY . It means toggled. Therefore, the toggling ratio of the modulation drive signal (SM) is twice that of the demodulation drive signal (S101/S103).

The slopes (and associated shaded areas) of S101/S103 are simplified diagrams representing energy recycling during transitions between voltage levels. Note that the transition periods of signals S101 and S103 overlap. If the piezoelectric actuator of the flap 101/R is mostly a capacitive load, energy recycling can be realized using the characteristics of the LC oscillator. Details of the energy recycling concept may be referred to U.S. Patent No. 11,057,692, incorporated herein by reference. Note that the piezoelectric actuator serves as an example and is not a limitation.

To emphasize that the flap pairs 102 are driven differently, the signals S101 and S103 can also be denoted as -SV and +SV, meaning that these drive signal pairs have the same waveform but different polarities. For illustration, as shown in FIG. 2, -SV is for S101 and +SV is for S103, but is not limited thereto. In one embodiment, S101 may be +SV and S103 may be -SV.

In another embodiment, under these circumstances driving signals S101 = V _BIAS - SV, S103 = V _BIAS + SV, there may be DC bias voltages (V _BIAS and V _BIAS ≠0). Such modifications should be considered within the scope of this disclosure.

Figure 2 also shows the difference in toggling rates between the modulation drive signal (SM) and the demodulation drive signal (±SV). The relative phase delay, which means timing alignment between the modulation drive signal (SM) and the demodulation drive signal (±SV), can be adjusted according to actual requirements.

In one embodiment, the drive circuit for generating the signals (SM, ±SV) may include a sub-circuit configured to generate a (relative) delay between the modulation drive signal (SM) and the demodulation drive signal (±SV). there is. The details of the subcircuit that generates the delay are not limited. Known techniques can be incorporated into the subcircuit. As long as the subcircuit can generate a delay to meet the timing alignment requirements (described in detail later), the requirements of the present invention are met and will be within the scope of the present invention.

Note that the tips of the flaps 101 and 103 are at substantially the same location (centered between the side walls 111L and 111R) and experience substantially the same air pressure at that location. Additionally, the flaps 101 and 103 move differently. Therefore, the movement of the tips of the flaps 101, 103 possesses a common mode rejection behavior similar to the common mode rejection known in the field of analog differential op-amplifier circuits, which means that the movement of the tips of the demodulating flaps 101, 103 This means that the displacement difference or |d ₁₀₁ - d ₁₀₃ | is hardly affected by the air pressure formed by the modulation flaps 105 and 107.

Common mode isolation, or modulator-to-demodulator isolation, can be demonstrated by FIG. 3. 3 illustrates simulated results resulting from an equivalent circuit model of device 100. The curves d ₁₀₁ and d ₁₀₃ represent the movement/displacement of the tips of the flaps 101 and 103, respectively. As can be observed in Figure 3, d ₁₀₁ and d ₁₀₃ fluctuate quite significantly due to the acoustic pressure (P104) generated by the modulation flaps 105/107, but in Figure 3 d ₁₀₁ -d The differential movement, represented by the curve marked ₁₀₃ , remains (substantially) consistent. That is, the width/gap of the valve opening 112 will remain constant even when the modulating portion 104 is operating. In other words, modulator movement has a negligible effect on the function and performance of the demodulator, which is what is meant by "modulator-to-demodulator isolation."

On the other hand, in the case of demodulator-to-modulator isolation, since the flaps 101/103 generate first-order harmonic resonance or standing waves within the chamber 115, as can be seen from Figure 1, the flaps 105 and Since the pressure applied to the flap 107 has substantially the same magnitude but opposite polarity, the movement of the flap 105 and 107 undergoes a change (due to P102) of equal magnitude but opposite polarity. This creates two ultrasonic waves (one at 105 and the other at 107) with the same magnitude but opposite polarity. When these two ultrasonic waves propagate to a location above the valve opening 112 (indicated by the dashed area in Figure 1), they merge into one pressure. Because the location of this "merge" occurs at the center of device 100 along the Creates a net rest with little interference in operation.

By way of example, Figure 4 shows that S _IN is a 10-tone equal amplitude test signal (within 650 to 22K Hz and has the same log scale interval) of the device 100. Plot the simulated frequency response of the sound pressure level (SPL), measured at 1 meter away from device 100, under the conditions in which the equivalent circuit simulation model is used. In the current simulation, the ultrasonic carrier frequency is set to f _UC = 192KHz and the valve operating frequency is set to f _{D_V} = f _UC /2=96KHz.

Demodulator-to-modulator isolation can be demonstrated by the absence of extraneous spectral components at and around 96 KHz (pointed with block arrows in Figure 4), indicating a high level of isolation.

As a result, the interference of the movements of these two flap pairs (101/103 vs. 105/107) is minimized through common mode (in the modulator) versus differential mode (in the demodulator) orthogonality/alignment.

Additionally, the percentage of time the valve remains open, or duty factor, is an important factor affecting the output of device 100. Increasing the amplitude of the driving voltage (S101, S103) increases the amplitude of movement of the flaps (101, 103), thereby increasing the maximum opening width of the valve opening 112, and increasing the driving voltage increases the duty factor of valve opening. The factor of valve opening also increases. In other words, the duty factor of the valve opening 112 and the maximum opening width/gap of the valve opening 112 may be determined by the driving voltages S101 and S103.

When the opening duty factor of the valve approaches 50% resulting from one of the previously mentioned equivalent circuit simulation models, such as the example shown in Figure 5, each The period of valve opening overlaps with the same half-cycle of the amplitude-modulated ultrasonic standing wave at a location above the valve opening 112 (indicated by the dashed area in Figure 1). By synchronizing and timing the opening-closing of the valve opening 112 to the in-chamber standing wave, illustrated by the curve labeled V(p_vlv) in FIG. 5, to V(ep_vlv). A nicely shaped output pressure pulse is generated, illustrated by the labeled curve.

In Figure 5, the curve labeled V(d2)-V(d3) represents the displacement difference of the flaps 101 and 103, that is, d101-d103, and the curve labeled V(opening) represents the opening of the virtual valve 112. It represents degrees. |V(d2)-V(d3)| When > TH, V(opening) > 0, and TH is a threshold value defined by parameters such as the thickness of the flaps 101 and 103, the slit width between the flaps 101 and 103, and the boundary layer thickness. A well-ordered form of V(ep_vlv) may mean that the pulse exemplified by V(ep_vlv) is highly asymmetric, unlike V(p_vlv), which is highly symmetric. The asymmetry of the output pressure pulse shows a low frequency component (i.e. the frequency component in the audible band) of the air pulse generated by the air pulse generator or simply the APG device, which is a desirable feature for an APG device. The higher the asymmetry, the stronger the baseband frequency component of the air pulse. A zoomed-out view of Figure 5 is illustrated in Figure 6, which shows the asymmetry of V(ep_vlv) corresponding to the envelope of the baseband sound signal at 1.68 KHz. In the present invention, the opening 112 is configured such that the displacement difference between the flap 101 and the flap 103 is greater than a threshold value, for example, |V(d2)-V(d3)| > When TH, it is open/formed or in the open state, otherwise it is closed or in the closed state.

Also, |V(d2)-V(d3)| Maximum output is observed to occur when the duty factor of valve opening, defined as >TH, is equal to or slightly greater than 50%, such as in the 55-60% range, but is not limited to this. However, when the duty factor of valve opening is much higher than 50%, such as 80~85%, more than half a cycle of the ultrasonic standing wave in the chamber will pass through the valve, so that the leading portions of the standing waves with different polarities are separated from each other. This cancels out, lowering the net SPL output from device 100. Therefore, it is generally desirable to keep the duty factor of valve opening close to 50%, generally in the range between 50% and 70% (where duty factors between 45% and 70% are within the scope of the present invention).

In addition to the duty factor, to ensure modulator-to-demodulator isolation, it is proposed that the resonant frequency f _{R_V} of the demodulation flaps 101/103 deviates sufficiently from the ultrasonic carrier frequency f _UC , which is another design factor.

Under the constraint that the valve opening duty factor is equal to 50% for any given thickness of the flaps 101/103, the higher the resonance-to-drive ratio ( f _{R_V} : f _{D_V} or f _{R_V} / f _{D_V} ), the more the valve operates. It can be observed that it can be opened wide. Since the output of device 100 is positively related to the maximum valve opening width, it is desirable for the resonance-to-actuation ratio to be greater than unity.

However, when f _{R_V} is within the range of f _UC ± max( f _SOUND ), the flaps 101/103 start to resonate with the AM ultrasonic standing wave, transferring part of the ultrasonic energy to the common mode deformation of the flaps 101/103 ( deformation), where max( f _SOUND ) may represent the maximum frequency of the input audio signal (S _IN ). This common mode deformation of the flaps 101/R causes the volume above the flaps 101/103 to vary, resulting in pressure variations within the chamber 105 near the valve opening 112 over the affected frequency range. This causes the SPL output to deteriorate.

To avoid frequency response variations due to valve resonance, it is desirable to design the flaps (101/103) with a resonance frequency outside the range of ( f _UC ±max( f _SOUND ))×M, where M is manufacturing tolerance, temperature This is a safety margin that covers factors such as, but not limited to, altitude, altitude, etc. In general, it is desirable for f _{R_V} to be significantly lower than f _UC , such as f _{R_V} ≤( f _UC - 20KHz)×0.9, or significantly higher than f _UC , such as f _{R_V} ≥( f _UC + 20KHz)×1.1. Note that 20 KHz is used here because it is well accepted as the highest frequency that humans can hear. In applications such as HD-/Hi-Res Audio, 30KHz or 40KHz may also be adopted as max( f _SOUND ), so the above formula must be modified accordingly.

It is also assumed that w ( t ) and z ( t ) represent time functions for amplitude modulated ultrasonic acoustic/air waves (UAW) and ultrasonic pulse arrays (UPA) (consisting of multiple pulses). The openings 112 are formed periodically at an opening rate of the ultrasonic carrier frequency f _UC , so that z( t ), denoted as r (t), can be expressed as r ( t ) = z ( t )/ w ( t ) . The rate function of vs. w ( t ) is periodic with the opening rate of the ultrasonic carrier frequency f _UC . In other words, z ( t ) can be viewed as the product of w ( t ) and r ( t ) in the time domain, i.e. z ( t ) = r ( t )· w ( t ), and the synchronous demodulation operation performed in the UAW can be viewed as w ( t ) multiplied by r ( t ) in the time domain. This means that z ( t ) can be viewed as the convolution of W ( f ) and R ( f ) in the frequency domain, that is, Z(f) = R ( f )* W ( f ), where * is the convolution We denote the solution operator, and the synchronous demodulation operation performed in UAW can be viewed as a convolution of W ( f ) and R ( f ) in the frequency domain. Note that when r ( t ) is periodic in the time domain with a rate of frequency f _UC , R ( f ) is discrete in the frequency domain where the frequency/spectral components of R ( f ) are equally spaced by f _UC . do. Therefore, the convolution or synchronous demodulation operation of W ( f ) and R ( f ) involves/consists of shifting W ( f ) (or its spectral component in UAW) by ± n × f _UC , where n is an integer. Here r ( t )/ w ( t )/ z ( t ) and R ( f ) /W ( f )/ Z(f) form a Fourier transform pair.

Figure 7 is a schematic diagram of an APG device 200 according to one embodiment of the present invention. Since device 200 is similar to device 100, the same notation is used. Unlike device 100, device 200 further includes an enclosing structure (enclosure) 14. A chamber 125 is formed between the surrounding structure 14 and the cap structure 11. As indicated by lines 135/137, a vent 113L/R in the ceiling 117 located each λ _UC /4 from the side wall 111L/R at the node of the ultrasonic normal pressure wave P104. ) is formed.

The purpose of vent 113L/R in FIG. 7 is to allow airflow generated during demodulation operation to be vented from chamber 115 (as indicated by the two dashed two-way pointed curves between 112 and 113L/R). By allowing the difference between the average pressure outside the surroundings and inside chamber 115 to be minimized and the functioning of chamber 125 to interfere with the spectral components carried into chamber 125 by airflows, such that these airflows produce additional audible sound signals. is to prevent the formation of. By placing vents 113L/R at the nodes of the steady pressure wave, spectral components around f _UC are prevented from escaping chamber 115, allowing demodulation to form an ultrasonic pulse array (UPA) and achieve the desired air pressure (APPS). A pulse speaker effect can be created.

In the present invention, an APG device with the APPS effect generally has a baseband frequency component (particularly a frequency component in the audible band) embedded within the air pulse output by the APG device at the ultrasonic carrier frequency, which is not only observable but also has significant intensity. It means to have. For an APG device that produces the APPS effect, the spectrum of the electrical input signal (S _IN ) is acoustically modified within the baseband of the audible spectrum (frequencies lower than the carrier frequency) through the generation of multiple air pulses by the APG device. , making it suitable for use in sound generation applications. The strength of the baseband generated through the APPS effect is related to the degree or amount of asymmetry of the air pulses generated by the APG device, which is discussed later.

The support structures 123L, 123R of the device 100 or 200 have parallel and straight walls (with respect to the X axis), wherein the space/channel between 123L and 123R functions as a sound outlet. Be careful. Simulation results using the finite element method (FEM) show that when the frequency rises above 350 KHz, lateral standing waves along the It shows that This lateral-resonance induced self-nullifying phenomenon reduces the energy transfer ratio (in the Z direction) to the wall height of 123L-123R.

To circumvent this problem, a horn-shaped outlet is proposed. For example, Figure 8 is a schematic diagram of a portion of an APG device 300 according to one embodiment of the present invention. Similar to device 100, device 300 is anchored to support structures 123L" and 123R", respectively, while also having an opening for generating a plurality of air pulses towards the surroundings through outlet 320. It includes flaps 101 and 103 configured to form 112). Unlike the support structures 123L, 123R of device 100, which have straight and parallel walls, the walls of support structures 123L", 123R" of device 300 are curved to form a horn-shaped outlet 320. It is oblique and has an angle θ that is not perpendicular to the X-axis or X-direction. Angles θ that are not right angles can be designed according to actual requirements. In one embodiment, the non-right angle θ may be 54.7°, but is not limited thereto. In the present invention, a horn-shaped outlet generally refers to an outlet having an outlet dimension or tunnel dimension that gradually becomes wider towards the periphery of the film structure.

9 and 10 respectively illustrate the frequency response of the energy transfer rate of devices 100, 300 for eight different displacements of flaps 101, 103, where Dvv=k is the displacement of the tip of each flap in kμ. means M, which produces a differential shift of 2 kμ M. Figures 9 and 10 are simulated using FEM. Comparing Figures 9 and 10, the energy transfer rate of device 100 begins to roll-off above 170 KHz with some jumps and dips as the frequency rises above 170 KHz. generate; Device 300 produces an energy transfer rate that maintains an upward trend above approximately 120 KHz, with a much smoother frequency response for frequencies above 170 KHz. This means that the frequency response of the energy transfer rate (above 170 KHz) of device 300 is much smoother than that of device 100, which is consistent with the ultrasonic pulse rate (i.e. ultrasonic carrier frequency f _UC ) and higher order harmonics (e.g. : n × f _UC ) is an advantage for APG devices operating at Device 300 also produces an energy transfer rate that is approximately 5 times higher than that produced by device 100. Therefore, from Figures 9 and 10, it can be seen that the horn-shaped outlet provides a better energy transfer rate to the APG device.

Figure 11 shows an embodiment of a two-step etching/fabrication method for etching a wall at two different angles. First, the wall of 123R"/123L" was etched at a tapered angle (as shown in (b) of Figure 11), and the tapered wall (as shown in (c) of Figure 11) was etched. Cover with photoresist or spin-on dielectric using a spray coating method. The photoresist or spin-on dielectric (as shown in (d) of Figure 11) is patterned by a photolithography method, and then the walls of 124L and 124R (as shown in (e) of Figure 11) are straightened. Etch at an angle. The provided manufacturing method is for illustrative purposes only and the scope of the present invention is not limited thereto.

Figure 12 is a schematic diagram of an APG device 400 according to one embodiment of the present invention. Device 400 is modified from Figure 7 of US Application No. 17/553,806 and is similar to device 100 shown in Figure 1 of the present invention. Unlike device 100, device 400 includes only flap pair 102 (but no flap pair 104). The flap pair 102 is for demodulating operation (synchronized to an amplitude-modulated ultrasonic carrier wave at frequency f _UC to form an opening 112 to generate air pulses according to the envelope of amplitude-modulated ultrasonic barometric pressure changes). It is configured to perform both modulation operations (to form amplitude-modulated air pressure changes with the ultrasonic carrier frequency f _UC ).

12, U104 and P104 represent the pressure profile and airflow profile formed by the flap pair 102 in response to the modulated drive signal (SM), and U102 and P102 represent the flap pair in response to the demodulated drive signal (±SV). The pressure profile and airflow profile formed by (102) are shown. Here, the demodulation drive signal is expressed as ±SV to emphasize that the flap pair 102 is differentially driven (meaning that the demodulation drive signals +SV and -SV have the same magnitude but opposite polarity) to perform the demodulation operation. For example, S101 and/or S103 can be expressed as -SV and/or +SV.

In other words, the modulator and demodulator are co-located on/as flap pair 102 . Like device 100, the film structure 10 of the flap pair 102 of device 400 is operable to have a common mode shift to perform modulation as well as a differential mode shift to perform demodulation.

In other words, the “ modulation operation ” and “ demodulation operation ” are performed simultaneously by the same pair of flaps 102. This is achieved by a new drive signal wiring scheme, such as the one shown in FIG. 3 , where the colocation of the “modulation operation ” with the “ demodulation operation ” is achieved. Assuming that device 400 may include actuators 101A/103A disposed on flaps 101/103 and that actuators 101A/103A include an upper electrode and a lower electrode, both of the upper and lower electrodes may have A modulation drive signal (SM) and a demodulation drive signal (±SV) can be received.

In one embodiment, one electrode of actuator 101A/103A may receive a common mode modulated drive signal (SM); The other electrode may receive a differential mode demodulation driving signal (S101(-SV)/S103(+SV)). For example, diagrams 431 and 433 shown in Figure 13 illustrate details of area 430 shown in Figure 12. As shown in diagrams 431 and 432, the lower electrode of actuator 101A/103A receives the common mode modulated drive signal SM; The upper electrode of the actuator 101A/103A receives the differential mode demodulation drive signal S101(-SV)/S103(+SV). An appropriate bias voltage (V _BIAS ) may be applied to the lower electrode (as diagram 432 shows) or the top electrode (as diagram 432 shows), wherein the bias voltage (V _BIAS ) is the actual It can be decided depending on the requirements.

In one embodiment (shown in diagram 433), one electrode of actuator 101A/103A is connected to a common mode modulated drive signal (SM) and a differential mode demodulated drive signal (S101(-SV)/S103(+SV)). Can receive all; The other electrode is biased appropriately. In the embodiment shown in diagram 433, the lower electrode receives a common mode modulated drive signal (SM) and a differential mode demodulated drive signal (S101(-SV)/S103(SV)); The top electrode is biased.

The driving signal wiring method shown in FIG. 13 (without considering V _BIAS ) is such that the applied signal of one actuator (e.g., 101A) is or includes -SM-SV, while the applied signal of the other actuator (e.g., 103A) is -SM-SV. The goal is achieved if the signal is or contains -SM+SV. Please note that the driving signal wiring method may be modified or changed depending on the actual situation/requirements. A common mode signal component between the two applied signals applied to the flap pair 102 includes a modulating drive signal (SM(V _BIAS plus)), and a differential mode between the two applied signals applied to the flap pair 102. As long as the signal component includes a demodulated drive signal (SV), the requirements of the present invention are met and are within the scope of the present invention. Here (or in general) the common mode signal component between two arbitrary signals a and b can be expressed as ( a + b )/2; The differential mode signal component between two arbitrary signals a and b can be expressed as ( a - b )/2.

Additionally, to minimize cross-coupling between the modulating operation (resulting from the drive signal SM) and the demodulating operation (resulting from the drive signal ±SV), in one embodiment, the flaps 101, 103 have mechanical configuration, dimensions, and electrical properties. In all, they are made as mirrored/symmetric pairs. For example, the cantilever length of flap 101 should be the same as that of 103; The membrane structure of flap 101 must be the same as that of flap 103; The position of the virtual valve 112 should be centered between or equally spaced between the flap 101 and the two support walls 110 of the flap 103; The actuator pattern deposited on flap 101 should mirror the pattern on flap 103; The metal wiring for the actuators deposited on the flaps 101, 103 must be symmetrical. Here, some items are designations for mirrored/symmetrical pairs (or flaps 101, 103 are mirrored/symmetrical), but are not limited to this.

λ_UC = C / f _UC

2.10 mm임). 도 14에서 알 수 있는 바와 같이, 장치(400)는 낮은 주파수 대역에서 높은 SPL의 사운드(100Hz 보다 작은 주파수에 대해 적어도 99dB)를 생성할 수 있다.14 illustrates a set of frequency response measurements of a physical embodiment of device 400 in an IEC711 occluded ear emulator, where the drive scheme shown in diagram 431 is used to drive device 400. The Vrms for the modulation drive signal (SM) for the lower electrode is 6 Vrms, and the Vpp (peak-to-peak voltage) for the demodulation drive signal (±SV) for the upper electrode is 5Vpp. to 30 Vpp, and a GRAS RA0401 ear simulator is used to measure the acoustic results. The operating frequency of device 400 (i.e. ultrasonic carrier frequency f _UC ) is 160 KHz and the device dimensions are designed accordingly (i.e. W115 for C = 336 m/s

λ _{U C} = C / f _{U C}

is 2.10 mm). As can be seen in Figure 14, device 400 is capable of producing high SPL sound (at least 99 dB for frequencies less than 100 Hz) in the low frequency band.

Additionally, FIG. 15 illustrates and analyzes measurement results of the device 400 shown in FIG. 14. In Figure 15, the SPL at 100 Hz (bold dashed line) and 19 Hz (bold solid line) in Figure 14 is plotted against Vvtop(Vpp), with Vvtop(Vpp) applied to the top electrode as shown in connection diagram 431. is the peak-to-peak voltage for the demodulated driving signal. From Figures 14 and 15, it can be seen that SPL increases as Vvtop increases. In addition, simulation results of the equivalent lumped-circuit model of the device 100 also showed that the SPL increases as the amplitude of the (valve drive or) demodulation drive signal increases. Therefore, it can be seen that the volume of the sound generated by the air pulse generator of the present invention can be adjusted through the amplitude of the demodulation drive signal.

Based on the results of Figures 14 and 15, it can be concluded that the concept of modulator-demodulator co-location is valid, which means that the modulation (forming amplitude-modulated ultrasonic barometric pressure changes) and demodulation (forming amplitude-modulated ultrasonic pressure changes) performed by the device 400 are valid. This means that it successfully creates an APPS effect (which creates an asymmetric air pulse by miraculously forming an opening). It may therefore be possible to reduce the chamber width (e.g., W115 of device 100).

For example, Figure 16 is a schematic diagram of an APG device 500 according to one embodiment of the present invention. Device 500 is similar to device 400, with flap pair 102 also actuated via one of the actuation methods shown in FIG. 13, but is not limited thereto. Compared to device 400, the chamber width W115' of device 500 is reduced by half. In one embodiment, the chamber width W115' of device 500 may be λ _UC /2.

Additionally, a standing wave in the chamber such as 115 in FIG. 12 or 115' in FIG. 16 may not be required, meaning that the chamber width (W115) does not need to be λ _UC or λ _UC /2, and the side walls (111R/111R' and 111L) may not be required. /111L') means there is no need to form/maintain/reflect a plane wave. It is free/flexible to change the shape of the chamber to optimize different factors, for example by reducing the chamber length, thus improving the sound production efficiency, which can be evaluated as SPL per area of the device (mm ² ).

Figure 17 is a schematic diagram of an APG device 600 according to one embodiment of the present invention. Device 600 may include subassemblies 610 and 640. In one embodiment, subassemblies 610, 640 may be fabricated via known MEMS processes and held together through layers 620 using a bounding or adhesive material such as a dry film or other suitable die attach material/method. Can be bound. The subassembly 610 itself can be viewed as an APG device (as will be described in detail later in FIG. 26 and related paragraphs) that includes a flap pair 102 or film structure 10. The subassembly 640 can be viewed as a cap structure.

Similar to device 500, device 600 includes, but is not limited to, a pair of flaps 102 with flaps 101 and 103 driven via one of the drive schemes shown in Figure 13, including, but not limited to, device ( The flap pair 102 of 600 forms an ultrasonic air pressure change amplitude-modulated with the ultrasonic carrier frequency f _UC , forms an opening 112 at a rate synchronized with the ultrasonic carrier frequency f _UC , and flows through the outlet according to the ultrasonic air pressure change. It is operated to generate multiple air pulses toward the surroundings.

Unlike device 500, a conduit 630 is formed inside device 600. Conduit 630 connects the air volume above virtual valve 112 (slit between flap 101 and flap 103) to the surrounding environment. Conduit 630 includes a chamber 631, a passageway 632, and an outlet 633 (or zone 631-633). Chamber 631 is formed between film structure 10 and cap structure (subassembly) 640. Passageway 632 and outlet 633 are formed within cap structure (subassembly) 640.

The chamber 631 can be viewed as a semi-occluded compression chamber, and the air pressure within the compression chamber 631 can be compressed or rarefied in response to the common mode modulation drive signal (SM), and the ultrasonic air pressure A change/wave is generated and supplied directly to the passage 632 through an orifice 613. The passage 632 acts as a waveguide, and its shape and dimensions must be optimized so that pressure changes/pulses generated in the region/chamber 631 can be efficiently propagated to the outside. The outlet 633 is configured to minimize reflection/refraction and maximize coupling of acoustic energy to the surroundings. To this end, the tunnel dimension (e.g., width in the X direction) of the outlet 633 gradually becomes wider toward the periphery, and the outlet 633 may have a horn shape.

In one embodiment, the length/distance L 630 of conduit 630 between opening 112 (equivalently, flap pair 102 or film structure 10) and surface ₆₅₀ is (substantially) f It may be the quarter wavelength λ _UC /4 corresponding to _UC (e.g. with ±10% tolerance). For example, L ₆₃₀ may be 450㎛ when f _UC = 192KHz, but is not limited thereto. (Referring again to FIG. 16) an air pressure wave (a type of air pressure fluctuation) propagates along the Note that the distance between the virtual valve (opening) 112 and the side wall surface 111L'/111R' is λ _UC /4. 17, device 600 can be viewed as an air wave propagation path that folds/rotates by 90° to align with the Z-direction, such that the air wave or air pressure pulse is emitted directly toward the surroundings through the Z-direction. .

Figure 18 shows a snapshot of a FEM simulated pressure profile of a device similar to device 600 according to one embodiment of the invention. In Figure 18, auxiliary arrows are presented to indicate the polarity/sign of the pressure value. The difference between the device shown in FIG. 18 and device 600 is that a chamfer 635 is added to subassembly 640 at the interface between chamber 631 and passageway 632 to create an obstruction to airflow ( The idea is to minimize disturbance. 18, the pressure in zone 631 is about +500 Pa and the pressure in zone 632, closed to 633, is about -500 Pa. The brightest region represents the pressure nodal plane.

The nodal planes within zone 632 dictate the proper shaping of wave propagation, and the space/distance between nodal planes 632 and nodal planes outside the device is approximately 1.2*λ/2, where λ = 346 ( m/s)/192(KHz)), note that this is close to (and slightly larger than) λ/2. This means that there is uninterrupted pressure wave propagation at the speed of sound. In other words, pressure pulses or air waves generated by the film structure of device 600 are radiated toward the surroundings as shown in FIG. 18.

Figure 19 illustrates the IEC711 occlusion ear coupler SPL measurement results versus the frequencies of the physically implemented device 600, where the results are plotted corresponding to demodulated drive signals (±SV) with 20 Vpp and 15 Vpp. Additionally, the parameters of devices 400 and 600 for generating maximum SPL are compared in Table 1.

device 400 device 600 SV 30 Vpp 20 Vpp SM 6 Vrms (16 Vpp) 5 Vpp S.P.L. 142.39 dB at 19 Hz
131.44 dB at 100 Hz 143.52 dB at 19 Hz
133.44 dB at 100 Hz Die size ^{50mm2 30mm2}

As can be seen in FIGS. 14, 19, and Table 1, device 600 can achieve slightly higher SPL than device 400 with lower input amplitude while simultaneously reducing die size by 40%. This means that device 600 with conduit 630 is much more efficient in terms of power consumption and occupied silicon space/area.

570μM인 반면 λ_UC/2

900μM인 장치(600)의 예에서 λ_UC/2보다 상당히 작다. 구역(631)이 챔버 압축을 수행하기 위해서는 챔버(631)의 치수가 λ_UC보다 훨씬 작아야 한다. 일 실시예에서, 챔버(631)의 높이(H₆₃₁)는 λ_UC/5보다 작을 수 있으며, 즉 H₆₃₁ < λ_UC/5일 수 있다. 챔버(631)의 폭(즉, X 방향의 치수)은 필름 구조물(10)로부터 통로(632)를 향해 계단식 또는 테이퍼된(tapered) 방식으로 점점 좁아질 수 있으며, 여기서 두 경우 모두 본 발명의 범위 내에 있다.Typically, the width W631 of the chamber 631 is, for example W631

570 μM while λ _UC /2

It is significantly less than λ _UC /2 in the example of device 600 which is 900 μM. For zone 631 to perform chamber compression, the dimensions of chamber 631 must be much smaller than λ _UC . In one embodiment, the height H ₆₃₁ of chamber 631 may be less than λ _UC /5, that is, H ₆₃₁ < λ _UC /5. The width (i.e., the dimension in the It is within.

Figure 20 is a schematic diagram of an APG device 700 according to one embodiment of the present invention. Similar to device 600, device 700 includes subassemblies 710, 740 and has a conduit 730 formed therein. The subassembly 710 may be manufactured by a MEMS process and may also be viewed as an APG device. Chamber 705 is formed within subassembly 710. The subassembly 710 may itself be an APG device, which can be viewed as a combination of the squeeze mode operation disclosed in U.S. Patent No. 11,172,310, the virtual valve disclosed in US Patent No. 11,043,197, and the driving method illustrated in FIG. Nos. 11,172,310 and 11,043,197 are incorporated herein by reference.

Conduit 730 includes a chamber 731, a passageway/waveguide 732, and a horn-shaped outlet 733 (or zone 731-733), which directs the air volume below virtual valve 112 outward to the surrounding area. Connect to Unlike device 600, subassembly 740 may be formed/manufactured through techniques such as 3D printing, precision injection molding, stamping, etc. Passageway/waveguide 732 includes a first section that is an orifice 713 etched into the cap of subassembly 710 and a second section formed within subassembly 740, wherein a chamfer 735 is provided to minimize obstruction. may be added in the meantime. Chambers 705 and 731 overlap. The pressure change/wave generated by the flaps 101, 103 will be fed directly into the passageway/waveguide 732.

Figure 21 is a schematic diagram of an APG device 800 according to one embodiment of the present invention. Device 800 includes subassemblies 810 and 840. Subassembly 810 may be manufactured by a MEMS process and may have the same or similar structure to device 500, which can be viewed as an APG device, with flaps 101 driven by one of the schemes shown in Figure 13. 103), where a virtual valve (opening) 112 is formed. The subassembly 840 may be formed/manufactured through technologies such as 3D printing, precision injection molding, precision stamping, etc. Note that through the (demodulation) modulation operation, the subassembly 810 generates a plurality of airflow pulses.

A conduit 830 is formed within the device 840 to connect the air volume below the virtual valve 112 to the outside and surroundings. Conduit 830 comprises a (compression) chamber 831, a passageway/waveguide 832 and a horn-shaped outlet 833 (or section 631-633). The compression chamber 831 is configured to convert a plurality of airflow pulses into a plurality of air pressure pulses. Specifically, chamber 831 is a pressure pulse (Equation 1), where M _{0_ n} is the air mass inside the chamber 831 before the start of pulse cycle n , and △M _n is the air mass associated with the airflow pulse of pulse cycle n . Equation 1 represents the conversion of an airflow pulse into an air pressure pulse, and the converted air pressure pulse propagates into the passageway/waveguide 832. In one embodiment, subassembly 840 in region 831 may have a brass mouthpiece-like cross section profile.

Passage/waveguide 832 may have an impedance that is close to or matches the compression chamber 831 or is within ±15% of the compression chamber 831 to maximize the propagation efficiency of pressure pulses generated in region 831 out to the surroundings. there is. In one embodiment, propagation efficiency can be optimized by appropriately selecting the cross section area of passageway 832.

In the embodiment shown in FIG. 21 , the tunnel dimension ₍ e.g., width in _the A horn shape is formed. The cone shape of the outlet can be designed according to actual requirements. The tunnel dimensions of the outlet may be expanded to polynomial, purely linear, piecewise linear, parabolic, exponential, hyperbolic, etc., but are not limited thereto. As long as the tunnel dimension of the outlet gradually widens towards the periphery, the requirements of the present invention are satisfied and this is within the scope of the present invention.

In order to perform chamber compression in zone 831, the dimensions of the chamber/zone 831 are proposed to be much smaller than the wavelength λ _UC corresponding to the operating frequency f _UC . For example, in an embodiment where f _UC =160 KHz and λ _UC = (346 /160) = 2.16 mm, the height H ₈₃₁ is in the range λ _UC /10 to λ _UC /60 (e.g., H ₈₃₁ = λ _UC / 35 = 62 μm ), and the width W ₈₁₅ may be in the range λ _UC /5 to λ _UC /30 (e.g., W ₈₁₅ in the range 115 μm to 350 μm ), but is not limited to this. No.

The film structure 10 subdivides the spatial volume into a resonance chamber 805 on one side and a compression chamber 831 on the other side (or the remaining side), and by the characteristics of this subdivision, the chamber 805 and the chamber 831 The displacements due to the common mode movement of flaps 101, 103 as observed in space have exactly the same magnitude but opposite direction/polarity. In other words, a push-pull operation will be created with common mode movement of the flaps 101, 103, which increases the pressure difference across the flaps 101, 103 (e.g. : double), so the airflow will increase when the virtual valve 112 is opened.

Specifically, for compression chamber 831 with volume V1 and resonant chamber 805 with volume V2, the membrane/flap movement resulting in a volume difference DV (assuming DV << V1, V2) is ΔP _V1 = 1 - V1/(V1-DV) = -DV/(V1-DV) -Pressure change at V1 equal to DV/V1 and △P _V2 = 1 - V2/(V2+DV) = DV/(V2+DV) It causes a pressure change in V2 equal to DV/V2. The pressure difference between the two volumes may be ΔP _V2 - ΔP _V1 = DV/(V2+DV) + DV/(V1-DV). V1 V2 When Va, △P _V2 -△P _V1 DV/(Va+DV) + DV/(Va-DV) = DV·2Va/(Va ² - DV ² ) 2·DV/Va 2·ΔP _V2 , which means that the push-pull operation can double the pressure difference between the two subspaces separated by the flaps 101 and 103.

Figure 22 is a schematic diagram of an APG device 900 according to one embodiment of the present invention. Device 900 includes subassemblies 910 and 940. Subassembly 910 can be manufactured by a MEMS process and can be viewed as an APG device. Subassembly 940 may be manufactured by 3D printing. Similar to device 700 or subassembly 710, subassembly 940 can also be viewed as a combination of the squeeze mode operation disclosed in No. 11,172,310, the virtual valve disclosed in No. 11,043,197, and the actuation scheme illustrated in FIG. there is. In device 900, compression mode operation chamber 905 and compression chamber 931 are separate; In device 700, the compression mode operation chamber and the compression chamber are merged into chamber 731.

The effects of subassembly 810 and subassembly 910 are similar in terms of generating airflow pulses, but their operating principles are different. Subassembly 810 utilizes resonance; Assembly 910 utilizes compression and rarefaction of the squeeze mode operating chamber 905 caused by membrane (flap 101, 103) movement. Therefore the chamber width W ₉₀₅ no longer needs to satisfy any relationship with λ _UC , and thus the size of the chamber 905 can be reduced as much as practical/desired.

Figure 23 is a schematic diagram of an APG device A00 according to an embodiment of the present invention. Because resonance is not a requirement, the limitations of a rectangular cross-section of a chamber such as chamber 905 can be removed, and the geometry is more flexible to optimize pressure wave generation or wave propagation to the surroundings. For example, chamber A05 or subassembly A40 may have a brass mouthpiece-like cross-section.

Another aspect of device A00 in Figure 23 is that of “direct pressure coupling”. Instead of first passing through orifice 913 as in device 900, the pressure wave generated in compression chamber A05 of device A00 is coupled directly to conduit A32 and then to the surroundings through outlet A33. I'm going. This direct coupling between the compression chamber and the conduit/outlet eliminates the losses introduced by orifice 913, resulting in significant efficiency gains over device 900.

Figure 24 is a schematic diagram of an APG device B00 according to an embodiment of the present invention. Device B00 is similar to device A00. Unlike device A00, device B00 further includes a (cap) structure B11, and a chamber B05 is formed between the cap structure B11 and the film structure 10. Since a push-pull operation is performed with the chamber A05 formed on one side of the film structure 10 and the chamber B05 formed on the other side of the film structure 10, the airflow pulse can be improved.

Note that the air pulses generated by subassemblies 810 and 910 can be viewed as airflow pulses, and subassemblies 840 and 940 can be viewed as airflow to air pressure transducers with a trumpet-shaped cross-sectional profile. Meanwhile, the air pulses generated by subassemblies 610, 710, A10, and B10 can be viewed as air pressure pulses, which directly generate demodulated/asymmetric air pressure pulses and can be more efficient than devices 800, 900.

Additionally, subassemblies having a conduit formed therein or having a conduit having a trumpet-shaped cross-sectional profile may be an APG device as disclosed in US Pat. It can also be applied, but is not limited to this.

Figure 25 shows an example of timing alignment of virtual valve (VV) 112 opening for the APG device of the present invention. In Figure 25, the solid curve represents the flap common mode shift produced by the modulation-drive signal (SM), and the dark part in the background represents the acoustic resistance corresponding to the virtual valve, where darker means higher resistance. (VV is closed, thereby isolating the volume within the chamber from the surroundings) and brighter means lower resistance (VV is open, resulting in the volume within the chamber being connected to the surroundings).

In Figure 25(a), the timing of the open state of the virtual valve (VV) 112 is the maximum in the chamber (first peak), which is generally placed slightly before the flap reaches the most positive (first peak) common mode displacement. 1 peak) is aligned with the pressure achieved; The timing of the closed state of the virtual valve 112 is aligned with the minimum (second peak) pressure in the chamber being achieved, which typically lies slightly before the flap reaches its most negative (second peak) common mode displacement. The timing alignment shown in (a) of FIG. 25, where the maximum opening of VV 112 is aligned with the first peak pressure in the chamber, is to maximize the pulse amplitude of the airflow pulse, which is used in devices 100-500 (chamber but there is no conduit formed inside).

Meanwhile, in Figure 25(b), inspired by the valve timing of gas/piston engines in the automobile industry, the timing of the open state of the virtual valve 112 is shown in the common mode of the membrane (flap) moving toward the first direction. aligned with the maximum speed of movement; The timing of the closed state of the virtual valve 112 is aligned with the maximum speed of common mode movement of the membrane (flap) moving toward a second direction opposite to the first direction. The first direction is towards the periphery in the film structure. The timing alignment shown in (b) of FIG. 25 is intended to maximize the volume of airflow plus device 600 or devices 700-900, A00, B00 (having a conduit containing a chamber formed therein). It may be suitable for.

Figure 26 is a schematic diagram of an APG device C00 according to an embodiment of the present invention. Device C00 is similar to the previously introduced APG device and includes flaps 101 and 103. The flaps 101 and 103 may also be driven by the driving method shown in FIG. 13.

Unlike these devices, device C00 does not include a cap structure. Compared to the APG device introduced above, device C00 has a much simpler structure, requiring fewer photolithography etching steps, eliminating complex conduit manufacturing steps, and eliminating the need to bind two subcomponents or subassemblies together. The production cost of the device (C00) is greatly reduced.

Since no chamber to be compressed is formed under the cap structure, the acoustic pressure generated by the device C00 is mainly generated by the acceleration of the movement of the flaps 101 and 103. By aligning the opening timing of the virtual valve 112 (responsive to the modulated drive signal ±SV) with the acceleration timing of the common mode movement of the flaps 101, 103 (responsive to the modulated drive signal SM) , the device C00 can generate an asymmetric air (pressure) pulse.

Note that the space surrounding flaps 101, 103 is split into two subspaces, one in the Z>0 or +Z subspace and one in the Z<0 or -Z subspace. For any common mode movement of flaps 101, 103, a pair of acoustic pressure waves will be generated, one in subspace Z and the other in subspace -Z. These two acoustic pressure waves have the same magnitude but opposite polarity. As a result, when the virtual valve 112 is opened, the pressure difference between the two air volumes near the virtual valve 112 will neutralize each other. Therefore, when the timing at which the differential mode shift peaks, i.e. the timing at which VV 112 reaches maximum opening, is aligned with the acceleration timing at which the common mode shift peaks, the acoustic pressure that must be generated by the common mode shift This is suppressed/eliminated by the opening of the virtual valve 112, resulting in automatic neutralization between the two acoustic pressures on the two opposite sides of the flaps 101, 103, wherein the two acoustic pressures are of equal magnitude. But the polarity is opposite. This means that device C00 generates (almost) net-zero air pressure when virtual valve 112 is opened. Therefore, when the period of opening of the virtual valve 112 overlaps with the period of one of the (two) polarities of the acceleration of the common mode flap movement, the device C00 is either single-ended (SE) or SE type ( SE-like) barometric pressure waveforms/pulses, which are highly asymmetric.

In the present invention, a SE(shaped) waveform can mean that the waveform is (substantially) unipolar for a particular level. SE acoustic pressure wave can refer to a waveform that is (practically) unipolar with respect to the ambient pressure (e.g. 1 ATM).

Figure 27 shows an example of timing alignment of virtual valve (VV) opening according to one embodiment of the present invention. The timing alignment method shown in FIG. 27 can be applied to device C00. The solid/dashed/dotted curves in (a) of FIG. 27 represent the displacement/velocity/acceleration of the common mode movement of the membrane (flaps 101 and 103) in response to the modulation drive signal SM, and FIG. 25 Similarly, the background darkness represents the acoustic resistance due to the opening and closing action of VV 112. For illustration purposes, the waveform of membrane/flap movement in Figure 27(a) is assumed (or approximately plotted) to be a sinusoid with constant amplitude, where the velocity/acceleration waveforms are the first/second derivatives of the displacement waveforms. . As shown in Figure 27(a), the timing of peak VV opening is aligned with the timing of the first peak acceleration of common mode membrane/flap movement toward the first direction, and as discussed above, this timing alignment is Resulting in automatic neutralization between the two acoustic pressure waves generated in subspace +Z and -Z, causing the net acoustic pressure to be suppressed, as illustrated by the flat part of the SE barometric pressure waveform in Figure 27(b). .

Also, as shown in Figure 27(a), the timing of VV closing is aligned with the timing of the second peak acceleration of the common mode membrane/flap movement toward the second direction, with the second direction being opposite to the first direction. . Because the VV closes during/near the second peak acceleration, the acoustic pressure generated by the second peak acceleration of the flaps 101, 103 can radiate away from the flaps 101, 103, resulting in (in Figure 27) Highly asymmetric acoustic pressure waves occur, as illustrated by the half-sine portion of the SE barometric pressure waveform in b).

Note that the opening of the virtual valve 112 does not determine the strength/amplitude of the acoustic pressure pulse, but determines how strong the “near net zero pressure” (or automatic neutralization) effect is. When the virtual valve 112 opening is wide, the “net zero pressure” effect is strong, automatic neutralization is completed, the asymmetry will be strong/apparent, and consequently the baseband signal or APPS effect will be strong/significant. Conversely, when the virtual valve 112 opening is narrow, the “net zero pressure” effect is weak, automatic neutralization is incomplete, asymmetry is lowered, and the baseband signal or APPS effect is weakened.

In FEM simulations, device C00 is capable of producing 145 dB SPL at 20 Hz. From the FEM simulation, it can be seen that under the same operating conditions, the total harmonic distortion (THD) of device C00 is approximately 12 dB lower than that produced by device 600 (about 157 dB SPL at 20 Hz). ) is 10 to 20 dB lower than that of device 600. The simulation therefore verifies the efficacy of device C00, which is an APG device without a cap structure or chamber formed therein.

The statement that the timing of VV opening is aligned to the maximum pressure timing in the chamber or the maximum speed/acceleration of common mode membrane movement implicitly means that a tolerance of ± e % is allowed. That is, it is also within the scope of the present invention if the timing of VV opening is aligned to (1 ± e %) of the peak pressure in the chamber or the peak speed/acceleration of common mode membrane movement, where e % is 1% depending on actual requirements. , may be 5% or 10%.

For pulse asymmetry, Figure 28 shows full-cycle pulses (within one operating cycle T _CY ) with different degrees of asymmetry. In the present invention, the asymmetry can be evaluated as the ratio of p ₂ to p ₁ , where p ₁ > p ₂ and p ₁ is the first half-cycle pulse with a first polarity with respect to the level. represents the peak value of , and p ₂ represents the peak value of the second half-cycle pulse having the second polarity with respect to the level. In the acoustic domain, the level may correspond to ambient conditions such as ambient pressure (zero acoustic pressure) or zero acoustic airflow, where air pulses in the present invention may refer to airflow pulses or air pressure pulses.

1인 전체 사이클 펄스는 비대칭도가 낮다. 도 28의 (b)는 40% ≤ r = p ₂/p ₁ ≤ 60%인 전체 사이클 펄스를 예시한다. 도 28의 (b)에 도시되거나 r = p ₂/p ₁

50%인 전체 사이클 펄스는 중간 정도의 비대칭도를 가진다. 도 28의 (c)는 r = p ₂/p ₁ < 30%인 풀 사이클 펄스를 예시한다. 도 28의 (c)에 도시되거나 r = p ₂/p ₁ → 0인 풀 사이클 펄스는 비대칭도가 높다.Figure 28(a) illustrates a full cycle pulse with r = p ₂ / p ₁ > 80%. As shown in (a) of Figure 28 or r = p ₂ / p ₁

A full cycle pulse of 1 has low asymmetry. (b) of FIG. 28 illustrates a full cycle pulse with 40% ≤ r = p ₂ / p ₁ ≤ 60%. As shown in (b) of Figure 28 or r = p ₂ / p ₁

A full cycle pulse of 50% has a moderate degree of asymmetry. Figure 28(c) illustrates a full cycle pulse with r = p ₂ / p ₁ < 30%. The full cycle pulse shown in (c) of Figure 28 or where r = p ₂ / p ₁ → 0 has a high degree of asymmetry.

As discussed above, the higher the asymmetry, the stronger the APPS effect and baseband spectral component of the ultrasonic air pulse. In the present invention, an asymmetric air pulse refers to an air pulse with at least a moderate degree of asymmetry, meaning r = p ₂ / p ₁ ≤ 60%.

Note that the demodulation operation of the APG device of the present invention generates asymmetric air pulses according to the amplitude of the ultrasonic air pressure change generated through the modulation operation. In one respect, the demodulation operation of the present invention is similar to the rectifier of an amplitude modulation (AM) envelope detector in a wireless communications system.

In wireless communication systems known in the art, an envelope detector, which is a type of wireless AM (non-coherent) demodulator, includes a rectifier and a low-pass filter. The envelope detector generates an envelope corresponding to the input amplitude modulated signal. The input amplitude-modulated signal of the envelope detector is highly symmetrical, typically r = p ₂ / p ₁ →1. One goal of the rectifier is to transform a symmetric amplitude modulated signal such that the rectified amplitude modulated signal is highly asymmetric, with r = p ₂ / p ₁ → 0. After low-pass filtering the highly asymmetric rectified AM signal, the envelope corresponding to the amplitude-modulated signal is recovered.

The demodulation operation of the present invention, which converts symmetrical ultrasonic air pressure changes ( r = p ₂ / p ₁ → 1) into asymmetric air pulses ( r = p ₂ / p ₁ → 0), is performed using the rectifier of an envelope detector such as an AM demodulator. Similar to, where a low-pass filtering operation is used to recover the sound/music corresponding to the input audio signal ( _SIN ) or to be perceived by the listener or measured by sound detection equipment, the natural environment and the human auditory system (or microphone It is left to a sound detection device such as

Creating asymmetry is very important for the demodulation operation of APG devices. In the present invention, pulse asymmetry relies on proper timing of opening aligned with membrane (flap) movement that generates ultrasonic barometric pressure changes. Different APG configurations will have different timing alignment methodologies as shown in FIGS. 25 and 27. In other words, the timing of forming the opening 112 is specified so that the plurality of air pulses generated by the APG device are asymmetric.

APG devices that generate asymmetric air pulses can also be applied in air pump/mobility applications that may have cooling, drying, or other functions.

Additionally, power consumption can be reduced through appropriate cell and signal path placement. For example, Figure 29 illustrates a top view of an APG device D00 according to one embodiment of the present invention, and Figure 30 illustrates a cross-sectional view of device D00 along line AA' shown in Figure 29. Device D00 includes cells D01 to D08 arranged in an array. Each cell (D0x) may be one of the APG devices described above (e.g., 400 to C00). In Figure 30, conduitized subassemblies and cap structures have been omitted for brevity. Assume that all flaps of the device D00 are driven by the drive signal method 431, the upper electrode receives the signal +SV or the signal -SV, and the lower electrode receives SM-V _BIAS .

In Figure 29, a long rectangle extending along the Y direction represents the upper electrode of the flap or an actuator disposed on the flap. Shading in the background may indicate the lower electrode of the actuator or may indicate that the lower electrode of the actuator is electronically connected.

In device D00, the flap (eg 101) receiving the signal -SV and the flap (eg 103) receiving the signal +SV are spatially interleaved. For example, when flap 103 of cell D01 receives signal +SV, flap 101 of cell D02 is proposed to receive signal -SV. When the signals +SV, -SV toggle their polarity or during the transition period of the signals +SV, -SV, a capacitive load (discharge) charging current flows through the lower electrode in the X direction, and the effective resistance of the lower electrode, R _{BT ,P} (where _P refers to parallel current flow) will be low, which means that L/W 1 and due to the low power consumption of the device D00, where L/W represents the channel length/width in terms of (dis)charge current.

Meanwhile, the driving signals -SV, +SV are {+SV, -SV}, {-SV, +SV}, {+SV, -SV}, {-SV, +SV}, {+SV, -SV}, In the case of wiring in the pattern of {-SV, +SV}, {+SV, -SV}, {-SV, +SV} (not shown in Figure 29) - where {...,...} is Specifies the differential drive signal pair for one cell (D0x) -, the load (discharge) charge current will be in the Y direction, and the effective resistance of the lower electrode R _BT,S (where _S refers to the series current flow) is will be much higher (i.e. L/W 1, so R _BT,S R _BT,P ), the power consumption in this way will be higher.

In other words, by using the wiring scheme shown in FIG. 29 (taking cells D01 and D02 as examples), the flap 103 of cell D01 receiving signal +SV is connected to the cell receiving signal -SV ( D02) is spatially placed next to the flap 101 and the transition period of the signal ±SV temporarily overlaps, so that one flap ( The current from the lower electrode (e.g. 103 in D01) moves directly to the neighboring flap (e.g. 101 in D02). Therefore, the effective resistance of the lower electrode is greatly reduced, which also reduces power consumption.

Additionally, the operating frequency can be improved by integrating multiple cells (e.g. two). Specifically, the APPS (Air Pressure Pulse Speaker) sound generation method using the APG device of the present invention is a type of discrete time sampled system. On the other hand, it is generally desirable to increase the sampling rate in such sampled systems to achieve high fidelity. Meanwhile, in order to lower the required driving voltage and power consumption, it is desirable to lower the operating frequency of the device.

Instead of increasing the operating frequency with the sampling rate for one APG device, it is efficient to achieve high pulse/acting rates by temporally and spatially interleaving (at least) two groups of (subsystems) with low pulse/acting rates. am.

Figure 31 (showing spatial arrangement) is a top view of the APG device (E00) according to an embodiment of the present invention. Device E00 includes two cells E11 and E12 placed next to/adjacent to each other. Cell E11/E12 may be one of the APG devices of the present invention.

Figure 32 (illustrating time relationships) illustrates the waveforms of two sets A and B of (demodulated) modulated drive signals for cells E11 and E12. Set A includes a demodulation drive signal (±SV) and a modulation drive signal (SM); Set B includes a demodulation drive signal (±SV') and a modulation drive signal (SM'). In the embodiment shown in Figure 32, the demodulation drive signal of signal set B (+SV'/-SV') is a delayed version of the demodulation drive signal of signal set A (+SV/-SV). Additionally, the signals of signal set B (SV'/-SV') are the signals of signal set A (SV/-SV) delayed by T _CY /2, which is half the operating cycle, where T _CY = 1/ f _UC and f _UC represents the operating frequency for the cells (E11/E12). The modulation drive signal (SM') of set B can be viewed as an inverted or polarity inverted version of the modulation drive signal (SM) of set A. Signals (SM, SM') may have the relationship SM' = -SM or SM + SM' = C, where C is some constant or bias. For example, when the modulation drive signal (SM) of set A has a pulse (shown as a dashed line in Figure 32) with a negative polarity with respect to the voltage level within the period T ₂₂ , the modulation drive signal (SM') of set B ) will have a pulse (shown as a dashed line in Figure 32) with positive polarity for the voltage level within the period T ₂₂ .

By providing one set of set A and set B to cell E11 and the other set of set A and set B to cell E12, device E00 has a pulse/sampling rate equal to 2× f _UC . An array of pulses can be generated, where f _UC is the operating frequency for each cell.

Figure 33 is a plan view of the APG device (F00) according to an embodiment of the present invention. Device F00 includes cells F11, F12, F21, F22 arranged in a 2x2 array. The cell of device F00 may be one of the APG devices of the present invention. Two of the cells (F11, F12, F21, F22) can receive signal set A, and the remaining two cells can receive signal set B.

In one embodiment, cells F11 and F12 receive signal set A and cells F21 and F22 receive signal set B. In one embodiment, cells F11 and F22 receive signal set A and cells F12 and F21 receive signal set B. In one embodiment, cells F11 and F21 receive signal set A and cells F12 and F22 receive signal set B. Similar to device E00, this device also generates a pulse array with a pulse/sampling rate equal to 2× f _UC .

Conventional speakers that use physical surface movements to generate acoustic waves (e.g. dynamic drivers) face the problem of front/rear radiated wave cancellation. When a physical surface moves, causing air mass movement, a pair of sound waves is generated: a front-radiating wave and a back-radiating wave. The two sound waves cancel most of each other, so the net SPL is much lower than if only the front/back radiated waves were measured.

A commonly adopted solution to the front/rear radiated wave cancellation problem is to utilize a rear enclosure or open baffle. Both solutions require physical size/dimensions comparable to the lowest frequency wavelength of interest, for example a 1.5 meter wavelength at a frequency of 230 Hz.

Compared to conventional speakers, the APG device of the present invention occupies only a few tens of square millimeters (much smaller than conventional speakers) and produces tremendous SPL, especially at low frequencies.

This is achieved by generating asymmetric amplitude modulated air pulses, where the demodulating portion generates symmetric amplitude modulated air pressure changes through membrane movement and the demodulating portion generates asymmetric amplitude modulated air pulses through virtual valves. The modulation and demodulation sections are implemented by flap pair(s) fabricated in the same fabrication layer, reducing fabrication/production complexity. The modulation operation is performed via common mode movement of a pair of flaps and the demodulation operation is performed via differential mode movement of a pair of flaps, where the modulation operation (via common mode movement) and the demodulation operation (via differential mode movement) are performed by a single flap. Can be performed in pairs. Proper timing alignment between differential mode movement and common mode movement improves the asymmetry of the output air pulse. Additionally, the horn-shaped outlet and trumpet-shaped conduit help increase propagation efficiency.

In summary, the air pulse generating device of the present invention includes modulation means and demodulation means. The modulation means, which can be implemented by applying a modulation drive signal to the flap pair 102 or 104, generate ultrasonic sound/air waves amplitude-modulated at the ultrasonic carrier frequency in accordance with the sound signal. The demodulation means, which can be implemented by applying a pair of demodulation drive signals (+SV, -SV) to the flap pair 102 or periodically driving the flap pair 102 to form the opening 112, is ultrasonic waves. A synchronous demodulation operation is performed to shift the spectral component of an ultrasonic acoustic/air wave (UAW) by ± n × f _UC . As a result, the spectral component of the ultrasonic air wave corresponding to the sound signal is shifted to the audible baseband and the sound signal is reproduced.

Those skilled in the art will readily observe that numerous modifications and variations of the apparatus and methods may be made while retaining the teachings of the present invention. Accordingly, the above disclosure should be construed as limited only by the scope of the appended claims.

Claims (29)

An air pulse generator, comprising:
film structures
Including,
The film structure is operated such that the air pulse generating device generates a plurality of air pulses,
A horn-shaped outlet is formed in the air pulse generator, and the plurality of air pulses propagate through the horn-shaped outlet. According to paragraph 1,
The dimensions of the horn-shaped outlet gradually widen from the film structure toward the periphery. According to paragraph 1,
support structure
It further includes,
The horn-shaped outlet is formed between the support structures. According to paragraph 3,
The film structure includes a pair of flaps,
The flap pair is secured to the support structure. According to paragraph 1,
A conduit is formed within the air pulse generating device,
wherein the conduit includes a first chamber, a passageway, and the horn-shaped outlet. According to clause 5,
The dimensions of the first chamber taper from the film structure toward the passageway. According to clause 5,
The first chamber is formed by a first side of the film structure. In clause 7,
An air pulse generating device, wherein a second chamber is formed by a second side of the film structure. According to clause 8,
The film structure includes a pair of flaps,
wherein the flap pair is operative to perform differential mode movement. According to clause 5,
a third chamber is formed by the film structure,
The first chamber and the third chamber are connected through an orifice. According to clause 5,
The first chamber is semi-occluded, an air pulse generator. According to clause 5,
The height of the first chamber is less than 1/5 of the wavelength corresponding to the operating frequency of the air pulse generating device. According to clause 5,
The width of the first chamber is less than half the wavelength corresponding to the operating frequency of the air pulse generating device. According to clause 5,
subassembly
Including,
An air pulse generating device, wherein the passage and the horn-shaped outlet are formed within the subassembly. According to clause 14,
The first chamber is formed between the film structure and the subassembly. According to clause 5,
cap structure
Including,
The passage and the horn-shaped outlet are formed within the cap structure,
The first chamber is formed between the film structure and the cap structure. According to clause 5,
The length of the conduit is 1/4 of the wavelength corresponding to the operating frequency of the air pulse generator. A subassembly disposed or to be disposed within an air pulse generating device, comprising:
Conduit formed within the subassembly
Including,
The conduit includes a passageway and a horn-shaped outlet,
A subassembly, wherein the subassembly is or will be assembled with a device comprising a film structure. According to clause 18,
A subassembly, wherein the dimensions of the horn-shaped outlet widen toward the periphery. According to clause 18,
The subassembly of claim 1, wherein the conduit includes a first chamber. According to clause 20,
A subassembly wherein a dimension of the first chamber narrows toward the passageway. According to clause 20,
The subassembly is,
Comprising an area having a brass mouthpiece-like cross section profile,
The subassembly of claim 1 , wherein the first chamber is formed between the film structure and the region having the brass mouthpiece-like cross-sectional shape. According to clause 20,
The subassembly wherein the first chamber is semi-occluded. According to clause 20,
A subassembly, wherein the first chamber is formed between the subassembly and the device. According to clause 18,
A subassembly, wherein a chamfer is formed in the subassembly. According to clause 18,
The subassembly is formed through 3D printing technology or precision injection molding. According to clause 18,
The subassembly is formed by a MEMS (Micro Electro Mechanical Systems) manufacturing process. According to clause 18,
The device is a subassembly formed by a MEMS (Micro Electro Mechanical Systems) manufacturing process. According to clause 18,
the film structure is actuated to create an ultrasonic pressure gradient,
The air pulse generator generates a plurality of air pulses according to the ultrasonic air pressure change,
The subassembly wherein the plurality of air pulses propagate toward the surroundings through the horn-shaped outlet.