Method and system for acoustic cleavage

Abstract

A method and system for acoustic cleavage are provided. [Solution] An acoustic system is described, which includes a piezoelectric device, an AC power supply for supplying alternating current (AC) voltage, an AC-DC converter coupled to the AC power supply for converting the AC voltage supplied by the AC power supply to a direct current (DC) voltage, a function generator for generating an input signal at the resonant frequency of the piezoelectric device, and an amplifier coupled to the AC-DC converter, the function generator, and the piezoelectric device, wherein the amplifier generates an output signal by amplifying the input signal according to the DC voltage, and uses the output signal to drive the piezoelectric device.

Description

Technical Field

[0001] (Related Applications) This application claims the benefit of priority of U.S. Provisional Patent Application No. 63 / 513,536, filed on July 13, 2023, which is incorporated herein by reference.

[0002] (Statement Regarding Federally Sponsored Research or Development) This invention was made with government support under Contract No. 80NSSC23CA191 awarded by the NASA SBIR Ignite program. The government has certain rights in this invention.

[0003] (Field of the Invention) The embodiments described herein relate to semiconductor manufacturing and equipment, and more specifically to layer transfer.

Background Art

[0004] As the solar power and various power electronics industries move toward non-silicon materials, there is a relevant driving force for growing semiconductor devices on the same or different substrates, including silicon (Si), gallium arsenide (GaAs), indium phosphide (InP), gallium nitride (GaN), silicon carbide (SiC), aluminum nitride (AlN), diamond, etc. In traditional fabrication techniques, the substrate can be removed by back-side grinding after the formation of the semiconductor device layer. However, the substrate accounts for a significant portion of the overall device cost. To recoup some of these costs, it has been proposed to regenerate the growth substrate for multiple uses. Removal techniques such as laser lift-off generally involve an intermediate layer that can affect the quality of the device layer growth. Other techniques such as spalling are generally performed at high temperatures and can have significant variability in the cleaved surface condition. Recently, U.S. Patent No. 10,828,800 proposes the use of sound-assisted crack propagation for semiconductor wafer manufacturing. In such a configuration, a pre-formed crack is created in the substrate, a first stress below the critical point of the material is applied to the material, which is insufficient to initiate the crack, and then ultrasonic waves are applied to the material, controlled so that the total stress applied to the crack tip of the material exceeds the critical point. The ultrasonic waves can then be controlled to propagate the crack in the material. [Overview of the project]

[0005] Acoustic cleaving devices, acoustic systems, acoustic circuits, and methods of use are described in relation to cleaving a workpiece. In one embodiment, the acoustic cleaving device includes a crack initiator system for creating a depression in the workpiece, a base stress system for inducing base stress on the workpiece, and an acoustic system for emitting sound waves into the workpiece to maintain controlled crack propagation through the material of the workpiece. Thus, the acoustic cleaving device may include an assembly of systems for preparing and cleaving a workpiece.

[0006] According to one embodiment of the present disclosure, the acoustic system includes a piezoelectric device, an AC power supply for supplying an alternating current (AC) voltage, an AC-DC converter coupled to the AC power supply for converting the AC voltage supplied by the AC power supply into a direct current (DC) voltage, a function generator for generating an input signal at the resonant frequency of the piezoelectric device, and an amplifier coupled to the AC-DC converter, the function generator, and the piezoelectric device, wherein the amplifier generates an output signal by amplifying the input signal according to the DC voltage, and uses the output signal to drive the piezoelectric device.

[0007] In one embodiment, the acoustic system is coupled to an AC power supply and further includes a power factor correction (PFC) circuit for correcting the power factor of the AC voltage supplied by the AC power supply. In another embodiment, the PFC circuit maintains a power factor of 0.9. In some embodiments, the acoustic system further includes a power converter coupled between an AC-DC converter and an amplifier, the power converter for converting a DC voltage into a drive voltage for a piezoelectric device. In another embodiment, the drive voltage is a first DC voltage, and a function generator is coupled to a power converter that provides a second DC voltage to the function generator.

[0008] In one embodiment, the function generator is coupled to an AC power supply and is powered using an AC voltage. In another embodiment, the piezoelectric device is a first piezoelectric device, and the acoustic system further includes a second piezoelectric device coupled to an amplifier, a first switch coupled between the first piezoelectric device and the amplifier, a second switch coupled between the second piezoelectric device and the amplifier, and a controller configured to close the first or second switch, allowing the amplifier to drive the first or second piezoelectric device, respectively. In another embodiment, the input signal is a first input signal, the resonant frequency is a first resonant frequency, and the output signal is a first output signal, and in response to the controller closing the second switch, the function generator provides the amplifier with a second input signal at a second resonant frequency of the second piezoelectric device, and the amplifier generates a second output signal based on the second input signal to drive the second piezoelectric device.

[0009] In one embodiment, the piezoelectric device is one of several piezoelectric devices in an acoustic system, and the function generator is one of several function generators that are part of a frequency selector circuit coupled to an amplifier, each function generator being configured to produce a specific input signal for driving a particular piezoelectric device among the several piezoelectric devices at the resonant frequency of that particular piezoelectric device. In another embodiment, the acoustic system further includes a controller that causes the frequency selector circuit to output a single input signal generated by one of the several function generators at any given time. In yet another embodiment, the frequency selector circuit includes several switches, each switch coupled between at least one of the several function generators and an amplifier, and the controller causes the frequency selector circuit to output a single input signal by closing the switch coupled between one function generator and the amplifier, and simultaneously opening the remaining switches among the several switches. In some embodiments, some switches are first some switches, and the acoustic system further includes second some switches, each of which is coupled between an amplifier and a different piezoelectric device from among some piezoelectric devices, and the controller is configured to close one of the second some switches and open the remaining switches of the second some switches based on one input signal output by a frequency selector circuit. In another embodiment, some of the first some switches are low-power switches, and some of the second some switches are high-power switches. In one embodiment, the amplifier is a single operational amplifier.

[0010] According to another embodiment of the present disclosure, the acoustic system includes a piezoelectric device having a resonant frequency, an AC power supply for supplying an alternating current (AC) voltage, a radio frequency (RF) amplifier coupled to the AC power supply and the piezoelectric device, and a function generator coupled to the RF amplifier, which causes the RF amplifier to generate an output signal based on the AC voltage for driving the piezoelectric device, the output signal having a frequency at the resonant frequency of the piezoelectric device.

[0011] In one embodiment, the acoustic system is coupled between an RF amplifier and a piezoelectric device and further includes a matching circuit for matching the input impedance of the piezoelectric device to the output impedance of the RF amplifier. In another embodiment, the input impedance is 47 ohms to 50 ohms. In some embodiments, a function generator includes a sweep generator for performing a frequency sweep within a frequency range that includes the expected resonant frequency of the piezoelectric device and determining the resonant frequency of the piezoelectric device within the frequency range based on the frequency sweep.

[0012] In one embodiment, the piezoelectric device is a first piezoelectric device, the RF amplifier is a first RF amplifier, the function generator is a first function generator, the resonant frequency is a first resonant frequency, and the acoustic system further includes a second piezoelectric device having a second resonant frequency, a second RF amplifier coupled between an AC supply unit and the second piezoelectric device, and a second function generator coupled to the RF amplifier, which causes the RF amplifier to generate another output signal based on an AC voltage for driving the second piezoelectric device and at the second resonant frequency. In another embodiment, the first and second function generators simultaneously drive their own respective piezoelectric devices. [Brief explanation of the drawing]

[0013] [Figure 1]This is an example flowchart of a sequence for cleaving a workpiece according to one embodiment. [Figure 2] This is a schematic top view example of an acoustic cleaning device according to one embodiment. [Figure 3] This is an illustrative schematic side cross-sectional view of a workpiece fixed within an acoustic system according to one embodiment. [Figure 4] This is a system-level diagram of an acoustic system according to one embodiment. [Figure 5] This is a schematic perspective view example of a workpiece including a device layer that is lifted off from a growth substrate, according to one embodiment. [Figure 6A] This is a schematic perspective view illustrating a recess formed on a workpiece according to an embodiment. [Figure 6B] This is a schematic perspective view illustrating a recess formed on a workpiece according to an embodiment. [Figure 6C] This is a schematic perspective view illustrating a recess formed on a workpiece according to an embodiment. [Figure 6D] This is a schematic perspective view illustrating a recess formed on a workpiece according to an embodiment. [Figure 6E] This is a schematic perspective view illustrating a recess formed on a workpiece according to an embodiment. [Figure 7A] This is an example of a recess pattern according to the embodiment. [Figure 7B] This is an example of a recess pattern according to the embodiment. [Figure 7C] This is an example of a recess pattern according to the embodiment. [Figure 8A] This is an example of a schematic perspective view of the base stressor layer according to an embodiment. [Figure 8B] This is an example of a schematic perspective view of the base stressor layer according to an embodiment. [Figure 9] This is an example of a schematic side cross-sectional view of a base stress system according to an embodiment. [Figure 10] This is a schematic perspective view example of a base stress system according to an embodiment. [Figure 11A]This is a schematic perspective diagram illustrating various arrangements of an acoustic generator according to the embodiment. [Figure 11B] This is a schematic perspective diagram illustrating various arrangements of an acoustic generator according to the embodiment. [Figure 11C] This is a schematic perspective diagram illustrating various arrangements of an acoustic generator according to the embodiment. [Figure 11D] This is a schematic perspective diagram illustrating various arrangements of an acoustic generator according to the embodiment. [Figure 11E] This is a schematic perspective diagram illustrating various arrangements of an acoustic generator according to the embodiment. [Figure 12A] This is a schematic perspective diagram illustrating an optional coupling agent used to couple one or more acoustic generators or acoustic enclosures to a workpiece, according to an embodiment. [Figure 12B] This is a schematic perspective diagram illustrating an optional coupling agent used to couple one or more acoustic generators or acoustic enclosures to a workpiece, according to an embodiment. [Figure 12C] This is a schematic perspective diagram illustrating an optional coupling agent used to couple one or more acoustic generators or acoustic enclosures to a workpiece, according to an embodiment. [Figure 12D] This is a schematic perspective diagram illustrating an optional coupling agent used to couple one or more acoustic generators or acoustic enclosures to a workpiece, according to an embodiment. [Figure 13] This is an illustrative schematic side cross-sectional view of an acoustic enclosure that functions as an acoustic absorber, according to one embodiment. [Figure 14] This is an illustrative schematic side cross-sectional view of an acoustic enclosure functioning as a diffuser, according to one embodiment. [Figure 15] This is an illustrative schematic side cross-sectional view of an acoustic enclosure functioning as a scattering material according to one embodiment. [Figure 16] This is an illustrative schematic side cross-sectional view of an acoustic enclosure and transducer that function to provide canceling interference according to one embodiment. [Figure 17]This is a block diagram of an acoustic system according to one embodiment. [Figure 18] This is another block diagram of an acoustic system according to one embodiment. [Figure 19] This is a block diagram of an acoustic system for driving multiple piezoelectric devices according to one embodiment. [Figure 20] This is another block diagram of an acoustic system for driving multiple piezoelectric devices according to one embodiment. [Figure 21] This is a block diagram of an acoustic system for driving several piezoelectric devices according to one embodiment. [Figure 22] This is a block diagram of an acoustic system according to one embodiment. [Figure 23] This is another block diagram of an acoustic system according to one embodiment. [Figure 24] This is a block diagram of a frequency selector according to one embodiment. [Figure 25] This is a block diagram of an acoustic system including a radio frequency (RF) amplifier according to one embodiment. [Modes for carrying out the invention]

[0014] Embodiments describe acoustic cleaving apparatuses and methods of use for cleaving workpieces such as semiconductor growth substrates having non-uniform or uniformly grown device layers. In one embodiment, the acoustic cleaving apparatus according to the embodiment may include an assembly of systems for preparing and cleaving the workpiece. For example, the acoustic cleaving apparatus may include a crack initiator system for creating depressions to facilitate fracture, a base stress system for approaching a critical stress to initiate crack propagation, and an acoustic system for controlled crack propagation. The crack initiator system may create depressions or patterns of depressions that function as nucleating sites for crack propagation, or alternatively, as part of a stressor for crack initiation at alternative locations. The base stress system may be configured to induce initial stress in the workpiece through thermal, mechanical, and / or acoustic sources such as an acoustic system. The acoustic system may include further subsystems such as an electronic system that generates electrical signals via an energy (voltage) source and energy output control, an acoustic generator that is activated by the electronic system to emit sound waves that increase stress within the workpiece, and an optional acoustic enclosure near one, some, or all sides of the workpiece to influence the interaction between the sound waves and the workpiece.

[0015] Another aspect of the present disclosure includes an acoustic system designed to drive one or more piezoelectric devices of an acoustic generator at a voltage relatively higher or lower than the operating voltage that may be used to operate at least a portion of the system. In particular, the system includes an acoustic cleavage circuit having a power amplifier which may be configured to power the piezoelectric devices from a high-voltage power supply. For example, the power amplifier may include a push-pull amplifier circuit that includes a pair of switches driven at high frequencies with a phase difference (e.g., by 180°) to alternately supply current from the high-voltage power supply to the piezoelectric device and draw current from the device to the power supply. As a result, the power amplifier provides the piezoelectric device with a high-voltage output signal as a series of high-voltage pulses to cause the device to vibrate according to (or based on) the frequency at which the pair of switches are driven. As a result, the amplifier drives the piezoelectric device by generating an output signal by amplifying the input signal using the power supplied by the power supply.

[0016] In addition, the acoustic cleavage circuit may include one or more capacitors, which may be in parallel with the push-pull circuit, as a capacitor bank. In particular, the capacitor bank may be coupled to the positive and negative rails of a high-voltage power supply to provide additional energy when the circuit alternates current from the power supply. As described herein, the push-pull circuit may be driven at high frequencies to vibrate a piezoelectric device. When current is drawn from the high-voltage power supply and then returned from the piezoelectric device to the power supply, the supplied voltage may drop. In particular, the system may have a significant amount of transient current due to the high-voltage swing caused by the high-frequency push-pull circuit switching. Also, the high-voltage power supply may not have sufficient stored voltage to drive the piezoelectric device at full power (e.g., because the current supplied by the power supply lags the applied voltage). As a result, the capacitor bank may be arranged to maintain a constant voltage across the piezoelectric device when the current alternates, providing an improved power factor.

[0017] In various embodiments, the description is made with reference to the drawings. However, certain embodiments may be carried out without one or more of these specific details, or in combination with other known methods and configurations. In the following description, numerous specific details, such as specific configurations, dimensions, and processes, are described in order to provide a full understanding of the embodiments. In other examples, well-known processes and manufacturing techniques are not described in particular detail so as not to unnecessarily obscure the embodiments. Throughout this specification, references to “one embodiment” mean that a particular feature, structure, configuration, or characteristic described in relation to that embodiment is included in at least one embodiment. Thus, when the phrase “in one embodiment” appears in various places throughout this specification, it does not necessarily refer to the same embodiment. Furthermore, certain features, structures, configurations, or characteristics may be combined in any preferred manner in one or more embodiments.

[0018] As used herein, the terms “above,” “on top of,” “towards,” “between,” “spanning,” and “on top” may refer to the relative position of one layer to another layer. A layer that is “above,” “on top of,” “spanning,” or “on top of” another layer, or that is “bonded to” another layer or “in contact” with another layer, may be in direct contact with the other layer or may have one or more intervening layers. A layer “between” layers may be in direct contact with the layer or may have one or more intervening layers.

[0019] Referring here to Figure 1, a flowchart of a sequence for cleaving a workpiece according to one embodiment is provided. In operation 1010, a crack initiator system 110 can be used to create a depression in the workpiece. The depression can cause cracks to form on one or more surfaces of the workpiece or provide irregularity to facilitate fracture of the workpiece at the depression or elsewhere within the workpiece. For example, in some embodiments, a pattern of depressions can be formed on the back surface of the growth substrate, while crack propagation proceeds orthogonally across the workpiece between the growth substrate and the device layer. The crack initiator can be mechanical, chemical, or optical methods (such as a laser) can be used to create the depressions. According to embodiments, the crack initiator system 110 can form a pattern of depressions, including lines, dots, etc., which can be on one or more sides of the workpiece to create weak points at one or more locations for crack formation and propagation (either at the depression locations or elsewhere). For example, the shape can be one or more continuous or discontinuous lines or dots in a straight or non-linear pattern. The location of the recess can be on one or all edges / sides of the workpiece at a predetermined height, near the edge, far from the edge, or on the top and / or bottom surface of the center of the workpiece. The location can follow one, several, or all edges / sides. The length of the recess pattern / shape can be from 1 μm to the entire length or width of the workpiece, while the depth can be from 1 μm to 500 μm, and the tip radius can be, for example, from 10 nm to 500 μm.

[0020] In operation 1020, a base stress is generated in the workpiece 102 using the base stress system 120. The base stress can reach a critical stress at which crack propagation begins within the workpiece, or it can be below that value so that crack propagation does not begin.

[0021] In a thermal system, one or more stressors (e.g., stressor layers) made of metal, polymer, ceramic, semiconductor, etc., having a different coefficient of thermal expansion (CTE) than the workpiece, can be attached to one or both (bottom / top) sides of the workpiece (and the device layer being cleaved) to form a composite with a stressor applicator. During operation, temperature changes from room temperature in the growing substrate, device layer, and stressor system generate loads and moments in the workpiece due to the difference in CTE. This stress generated in the workpiece is the base stress. In an exemplary embodiment, the base stress is introduced into the workpiece via the stressor layer by a substrate holder, which can be a cold plate or, alternatively, a hot plate.

[0022] In a mechanical system, the base stress can be introduced from any or a combination of tensile stress, compressive stress, bending stress, fatigue stress, and / or shear stress directly generated by one or more mechanical devices. In an acoustic system, the base stress can be introduced by the acoustic system 130, or a part thereof such as a dedicated piezoelectric material.

[0023] Next, in operation 1030, acoustic energy can be applied to the workpiece simultaneously and / or thereafter using the acoustic system 130 to maintain controlled crack propagation through the workpiece material. Then, in operation 1040, the cleaved device layer can be lifted off from the growing substrate (and vice versa).

[0024] Figure 2 is a schematic top view example of an acoustic cleavage apparatus 100 according to one embodiment. The cleavage apparatus 100 may include all systems and subsystems used to initiate crack propagation and lift off the cleaved layer (e.g., a device layer) from the workpiece. According to the embodiment, various components of the acoustic cleavage apparatus form a crack initiator system 110, a base stress system 120, and an acoustic system 130. The crack initiator system 110 may include a mechanical, chemical, or optical indenter that creates a depression in the workpiece to facilitate fracture of the workpiece in that depression or elsewhere. The base stress system 120 (which may be mechanical, thermal, and / or acoustic / electrical) can be used to reach a critical stress for initiating crack propagation, or a stress below this value where crack propagation does not proceed. The acoustic system 130 may be configured to emit sound waves into the workpiece to maintain controlled crack propagation through the material of the workpiece. The acoustic system may include an electronic system, an acoustic generator, and an optional acoustic enclosure. The crack initiator system, the base stress system, and the acoustic system may be located in the same or separate locations. The crack initiator system and the base stress system may also be applied in an interchangeable order before the acoustic system.

[0025] In a particular embodiment illustrated in Figure 2, the crack initiator system 110 includes a laser 112 that can be positioned above, below, or laterally adjacent to the side of a workpiece 102. The workpiece 102 may be supported in the crack initiator system 110 by the same or different substrate holders as those in the base stress system 120 and the acoustic system 130. For example, the workpiece 102 may be supported by a substrate holder 111 in the crack initiator system 110 and then transferred to a substrate holder 114 for processing in the base stress system 120 and the acoustic system 130. For example, a wand 101, a robotic arm 109, and a translation track 113 may be used to move the workpiece 102 between systems. For example, the wand 101 may be vacuum operated, but other forms of holding the workpiece 102 are envisioned, including finger clamps. In another embodiment, the workpiece 102 does not need to be supported by the substrate holder 111 when processed by the crack initiator system 110. For example, when processed by mechanical, chemical, or optical methods (e.g., laser 112) to form a depression, it may be sufficient to simply hold the workpiece with a wand 101 or a mechanical gripper.

[0026] In a particular embodiment illustrated in Figure 2, the base stress system 120 is a thermal system in which thermal stress is introduced into a workpiece 102 having a substrate holder via an optional bonding agent (e.g., adhesive, gel, etc.). For example, the thermal stress can be applied using substrate holders 111 and / or 114, which may be a cold plate (held below room temperature) or a hot plate (held above room temperature).

[0027] The workpiece 102 can be fixed together to both the base stress system 120 and the acoustic system 130, as shown in Figure 3. A high-level system diagram of the acoustic system 130 according to an embodiment is shown in Figure 4.

[0028] Referring to Figures 2 to 4, the acoustic system 130 according to the embodiment may comprise several subsystems, including an electronic system 140, an acoustic generator 132, and an optional acoustic enclosure 134. The acoustic generator 132 and / or the acoustic enclosure 134 may each be in direct contact with the workpiece 102 or may be separated from the workpiece and coupled to the workpiece by a coupling agent 135. In one embodiment, the acoustic enclosure 134 includes an (annular) opening 133 for receiving the workpiece 102. The electronic system may generate electrical signals via an energy source 142 (e.g., a low-voltage power supply and a high-voltage power supply), a signal generator 143, and an acoustic cleavage circuit 144, control the energy output, and activate the acoustic generator 132 (e.g., a piezoelectric material). As will become apparent in the following description, the acoustic system and acoustic generator can be utilized across a variety of systems. For example, the acoustic generator 132 (e.g., a piezoelectric material) can be used for crack propagation by the acoustic system 130 and for generating base stress in the base stress system 120.

[0029] The electronic system 140 can be any combination of energy storage components (including, but not limited to, batteries, capacitors, and supercapacitors), switches, voltage sources, amplifiers, relays, pulsers, etc. The electronic system may also have other circuit components, including optical oscillators, Schmitt triggers, etc., designed to reduce or increase the system's inductance, voltage overshoot, current overshoot, ringing, and flyback voltage.

[0030] The electrical signal generated by the electronic system 140 according to the embodiment can be a combination of pulses having a voltage amplitude of 0kV to 20kV, or greater than 20kV. The width of each pulse can be varied between 10ns and 10s, while the time t between pulses can be in the range of 20ns to 1s. The total number of pulses "n" can be 1, 2, or greater than 2. Each electrical pulse can have the same or different characteristics and can be sent to the same or different acoustic generators, or more specifically, piezoelectric materials. The signal can be one or more chirps, and the shape of the signal can be square, rectangular, triangular, sawtooth, sine wave, ramp, or any combination of shapes. The voltage amplitude can be 0kV to 20kV, or greater than (>20kV). The frequency of the signal frequency can be defined as 1Hz to 100MHz, and the number of repetitions "n" can be 1, 2, or greater than 2. The electronic system 140 can be connected to the acoustic generator 132 by lead wires 146, for example, wires.

[0031] Each acoustic generator 132 in the embodiment emits "sound waves" to increase the stress on the workpiece 102 and the device layer cleaved from the workpiece 102. Each acoustic generator 132 can be located on one side, several sides, or all sides of the workpiece. The type of sound wave generated can be planar or focused. The resonant frequency of the acoustic generator 132 can be 1 kHz to 100 MHz. The acoustic generator can be composed of one or more layers of piezoelectric material. Some acoustic generator assemblies can form different patterns, including but not limited to circular, square, or rectangular shapes.

[0032] The acoustic generator 132 can be in direct contact with the workpiece 102 (or its device layer), or it can be separated and coupled via a coupling agent 135 (as shown in Figure 3). The separation from the workpiece can be up to 50 mm and can be controlled by a robotic arm, spacer, or any other means. The coupling agent 135 may be located only between the workpiece 102 and the acoustic generator 132, or the entire system may be immersed in the coupling agent. In one embodiment, the acoustic generator 132 is used as part of a base stress system 120. Thus, acoustic generators 132, including separate groups of them, can be used for crack propagation and / or base stress.

[0033] The acoustic system 130 may further include an acoustic enclosure 134 that can be located adjacent to or surrounding one, some, or all sides of the workpiece. The acoustic enclosure 134 may influence (through reflection, absorption, etc.) the sound waves emitted by the cracks propagating during fracture.

[0034] Referring here to Figure 5, a schematic perspective example of a workpiece 102 including a lift-off device layer 106 according to one embodiment is provided. As shown, the workpiece 102 processed according to the embodiment may include a growth substrate 104, followed by a buffer layer 504 for absorbing stress and defects from lattice mismatch, followed by various additional functional layers 506, 508, 510, 512 (e.g., charge transport layer, active layer, blocking layer, confinement layer, etc.) depending on the device to be formed, a current diffusion layer 514, and an electrode layer 516. The device layer may be utilized for various electronic and optoelectronic functions and may be based, for example, on a III-V and / or II-VI semiconductor structure. For illustrative purposes only, one exemplary application of the growth substrate 104 may be GaAs, having a GaInP buffer layer, followed by device layers 506, 508, 510, 512 formed of materials such as GaAs, InAlP, and GaInP, a GaAlAs current diffusion layer 514, and a metal (e.g., Au) electrode layer 516. Such a laminate is provided for illustrative purposes only for cleaving the device layer 106 from the growth substrate 104, and it should be understood that embodiments are not limited to such exemplary laminates. As illustrated, the cleaved surface 105 may occur at the location of the buffer layer 504, or immediately below the buffer layer 504, or within the buffer layer 504, so that the growth substrate 104 can be regenerated and reused multiple times for subsequent growth of the device layer 106. According to embodiments, various depressions can be formed on the front / back and side surfaces of the workpiece. In particular, the depressions can be formed on the back surface 107 and the side surface 108 of the growth substrate 104, but embodiments are not limited in this way, and the depressions can also be formed on the device layer 106, such as the top surface 103 (of the electrode layer 516). In yet another embodiment, the depressions can be formed on the growth surface of the growth substrate 104 before the device layer 106 is formed.

[0035] Referring here to Figures 6A to 6E, schematic perspective view examples of recesses 402 formed on a workpiece 102 according to embodiments are provided. For example, the pattern of the recesses 402 can be formed by a laser 112, but embodiments are not limited in this way. As shown in Figure 6A, the recesses 402 can be along the side surfaces 108 of the workpiece 102, more specifically of the growth substrate 104. The recesses 402 can be along one side surface 108 or several side surfaces 108. As shown in Figure 6B, the recesses 402 can be along all side surfaces 108, and can be, for example, a continuous pattern around the workpiece 102 or the growth substrate 104. In the embodiment illustrated in Figure 6C, the recesses 402 are formed along the back surface 107 of the growth substrate 104, or the top surface 103 of the device layer 106. More specifically, the recesses 402 can be formed near an edge or side surface 108. The depressions 402 may be centrally located as shown in Figure 6D, or around all edges / sides 108 of the back surface 107 or top surface 103 as shown in Figure 6E. Various options are available. Depending on the embodiment, the depressions 402 may be single or in a pattern. For example, as shown in Figure 7A, the depressions may be continuous, for example, linear or other continuous patterns. As shown in Figure 7B, the depressions may be linear or nonlinear patterns, discontinuous or dashed. As shown in Figure 7C, the depressions may be a pattern of dots in a linear or nonlinear pattern. Various configurations, as well as combinations of shape and pattern, can be used to control crack formation and propagation.

[0036] In certain configurations, a pattern of dash or dot indentations 402 is formed along the back surface 107 and / or side surface 108 of the growth substrate 104. Indentations along the back surface 107 have been observed to increase stress by as much as 20% in the growth substrate 104 near the regrowth interface with the device layer 106. When a base stressor (e.g., heating / cooling) is applied, the additional stress generated across the non-uniform or uniform system of the growth substrate 104 and the device layer 106 can exceed a critical stress sufficient to lift off the device layer 106.

[0037] Referring here to Figures 8A and 8B, various configurations are provided in which the base stresser system includes a base stresser layer used to transfer thermal energy to the workpiece 102. In a particular embodiment illustrated in Figure 8A, the base stresser system includes a substrate holder 114, which may be a hot / cold plate, and a lower base stresser layer 122 on the bottom surface of the workpiece 102. For example, the lower base stresser layer 122 may be a polymer adhesive (e.g., epoxy, acrylic, etc.) deposited on the workpiece and then shrinking more than the workpiece 102 when cooled. For example, the material of the base stresser layer may be a thermosetting resin. A mismatch in the coefficient of thermal expansion (CTE) causes base stress. As shown in Figure 8B, an upper base stresser layer 124 is not essential but may also be provided on the top surface of the workpiece 102, or alternatively. Non-polymer materials may also be used. When in use, the base stresser layer may also function as a sacrificial layer, acting as a handle for lift-off of the device layer. Although illustrated as a single layer, it should be understood that the base stresser layers 122 and 124 can each be a single material layer or multiple layers of the same or different materials. Various configurations are possible. The base stresser layers can then be removed. The specific orientation of the workpiece 102 may depend on the specific circumstances; therefore, the top surface shown in Figure 8A may be the back surface 107 of the growth substrate 104, or alternatively, the top surface 103 of the device layer 106.

[0038] In alternative configurations, the base stress system 120 may include mechanical and / or electrical stressors. Referring here to Figures 9 and 10, Figure 9 is an illustrative schematic side section of the base stress system according to an embodiment. Figure 10 is an illustrative schematic perspective view of the base stress system according to an embodiment. In each of the embodiments illustrated in Figures 9 and 10, mechanical stress may be provided by a pneumatic positioning unit 702, and the mechanical stress on the workpiece 102 can be controlled by the pressure within the pneumatic positioning unit 702. Various components of the system can be maintained in precise locations using alignment mechanisms 704 (e.g., frames, plates, etc.) and fasteners 706 (e.g., screws, micrometers, etc.). In certain embodiments, illustrated acoustic generators can be used for both base stress generation in the base stress system 120 and crack propagation in the acoustic system 130. Specifically, an acoustic generator 132A (e.g., a piezoelectric material) can be used to generate base stresses such as tensile stress on the workpiece 102, and an acoustic generator 132B (e.g., a piezoelectric material) can be used for crack propagation such as shear stress on the workpiece 102, which can be fixed within the cavity 710. In the illustrated embodiment, the acoustic generators 132A and 132B may be mounted on one or more base stressor layers 124. The acoustic enclosure 134 may also be fixed within the system. In such a configuration, the opening 133 (see Figure 3) of the acoustic enclosure 134 may define the cavity 710.

[0039] The acoustic generator 132, whether used for base stress generation or crack propagation, can include various shapes and arrangements adjacent to the workpiece (e.g., in direct contact with the workpiece or separated from and coupled to the workpiece), and may be located on one, some, or all sides of the workpiece 102 according to the embodiment.

[0040] Figures 11A to 11E are schematic perspective illustrations of various arrangements of the acoustic generator according to embodiments. In the embodiment illustrated in Figure 11A, the acoustic generator may be similar in shape (e.g., circular) and size to the workpiece 102. The acoustic generator 132 may be located on the back surface 107 or the top surface 103 of the workpiece 102 according to the embodiment, or on both sides as shown in Figure 11B. The acoustic generator 132 may also have a different shape, such as rectangular or square, compared to the workpiece 102, as shown in Figure 11C. The acoustic generator 132 may also be patterned as shown in Figure 11D. For example, a particular pattern may assist in the direction of crack propagation. In the particular embodiment illustrated, the acoustic generator pattern includes a concentric ring surrounding the disk, but this is merely illustrative. If they are separate parts, the acoustic generator 132 may be connected to different acoustic sources. For example, such a concentric pattern may be implemented when the crack begins at the center of the workpiece. Referring to Figure 11E, multiple acoustic generators 132 can be distributed across the workpiece 102 and may be connected to different voltage sources, or to the same voltage source in different ways, to apply acoustic energy at different locations and / or at different times to control crack propagation. According to the embodiment, multiple acoustic generators 132 or arrays of acoustic generators can be used with timing differences, where the acoustic generators are triggered at different times and / or at different voltages. In the particular embodiment illustrated in Figure 11E, a 2x2 array is illustrated, but the arrays may be larger, such as 4x4, 8x8, etc. Such arrangements may be used, according to one embodiment, to control crack propagation from one side to the other across the workpiece 102.

[0041] In one embodiment, one or more acoustic generators 132 (or an array thereof) may optionally be held by a robotic arm 109 having an actuator and be lowered, for example, over a workpiece 102 to make direct contact with the workpiece, or to make contact with an optional bonding agent 135, such as a backing (e.g., adhesive layer) or ultrasonic gel applied to the workpiece 102 and / or the acoustic generators 132. The acoustic system 130 according to the embodiment may further include an optional acoustic enclosure 134 that may be positioned adjacent to or surrounding one, some, or all sides of the workpiece 102. The acoustic enclosure 134 may influence (through reflection, absorption, scattering, sound emission, etc.) the sound waves emitted by the crack propagating during fracture.

[0042] Referring here to Figures 12A to 12D, various exemplary configurations are illustrated in which, according to the embodiment, one or more acoustic generators 132 or acoustic enclosures 134 are coupled to a workpiece 102 using an optional bonding agent 135. In the embodiment illustrated in Figure 12A, for example, a bonding agent 135 such as an adhesive backing or gel can be applied to the back surface 107 and / or top surface 103 of the workpiece 102 and / or acoustic generator 132 or acoustic enclosure 134. The bonding agent 135 can assist in the transmission of sound waves between the acoustic generator 132 and the workpiece 102, or between the workpiece 102 and the acoustic enclosure 134. As shown in Figure 12B, the workpiece 102 may be immersed in the bonding agent 135 such as a gel, or completely covered with the bonding agent 122. In the schematic top view example of Figure 12C, the coupling agent 135 may be applied to an acoustic enclosure 134 or acoustic generator 132 that laterally surrounds the workpiece 102. Figure 12D illustrates, according to one embodiment, a workpiece 102 immersed in the coupling agent 135 and a top acoustic generator 132 on the coupling agent 135. In one embodiment, the configurations of Figures 12C and 12D are combined with the examples of Figures 2 and 3, etc. In such a configuration, the acoustic enclosure 134 may function as a reservoir for housing the coupling agent 135.

[0043] Referring now to Figure 13, in one embodiment, the acoustic enclosure 134 functions as an acoustic absorber that absorbs waves emitted at the boundary of the workpiece 102. For example, the acoustic enclosure can be formed from or contain materials such as acoustic foam, vinyl sound barrier, damping compound, or acoustic putty.

[0044] In the embodiment illustrated in Figure 14, the acoustic enclosure 134 may be a diffuser material that transmits emitted waves and prevents reflection as a boundary of the workpiece 102. In such a configuration, the crack can propagate throughout the workpiece 102 before waves reflected off the outer surface 139 of the diffuser material reach the crack tip. This can be facilitated by the material selection of the diffuser material and the depth (D) of the diffuser material between the inner surface 137 and outer surface 139 (e.g., surrounding the workpiece 102 laterally) that are laterally adjacent to the workpiece 102 in the direction of crack propagation. Such a diffuser material may have an acoustic impedance that matches the workpiece in order to transmit waves rather than reflect them. The acoustic impedance of the materials can define the transmission of sound waves from material to material. If the acoustic impedances of both materials match, the sound waves can propagate completely within the diffuser material. If the mismatch is large, a large portion of the acoustic waves may be reflected. According to the embodiment, the acoustic impedance of the diffuser material may be in the range of 0.0001 MRayl to 200 MRayl or higher. In some embodiments, the difference in acoustic impedance between the workpiece and the diffuser material may be less than 100 MRayls.

[0045] In one embodiment illustrated in Figure 15, the acoustic enclosure 134 functions as a scattering material capable of scattering waves emitted by the crack tip. As shown in Figure 15, the inner surface 137 and / or outer surface 139 of the acoustic enclosure can be roughened and may include irregularity or an irregular array of cavities 138 that can scatter waves emitted by the crack tip in alternating directions. The surface roughness (e.g., mean surface roughness, Ra), irregularity, or irregular array of cavities can be matched to the wavelength of the applied sound wave, which can be in the range of 1 nm to 1 mm, or more specifically, 10 nm to 500 μm. During operation, these scattered waves may have sufficiently low energy so as not to affect the crack tip. Waves can be absorbed during the scattering event before they can reach the crack tip.

[0046] In one embodiment illustrated in Figure 16, the acoustic enclosure 134 can be an acoustic generator 132 that emits a characteristic wave that destructively interacts with the wave emitted by the crack tip (i.e., noise cancellation). The frequency, shape, and amplitude of the applied sound wave can remain constant over time or be modified as the crack tip propagates.

[0047] As used herein, “coupling” of at least two components may mean electrically coupling the leads or connectors of one electronic component to the leads or connectors of another electronic component. For example, two electronic components may be electrically coupled such that current can flow from (or from outside one component) to (or into) the other component. In particular, two components may be electrically coupled such that they can communicate with each other (unidirectional or bidirectional) by transmitting and / or receiving input analog and / or input digital signals. In one embodiment, components may be coupled so that they are directly connected to each other. In another embodiment, components may be coupled together detachably via one or more connectors. In that case, the components may be detached and replaced as needed.

[0048] Figure 17 is a block diagram of an acoustic system 130 according to one embodiment. As described herein, it may be configured to drive an acoustic generator having one or more piezoelectric devices (or materials) using an electrical output signal (as a series of high-voltage pulses) to acoustically cleave a workspace (or substrate). As shown, the acoustic system 130 includes an operating (or low-voltage) power supply 154, a signal generator 143, a high-voltage power supply 152, an acoustic cleavage circuit 144, and an acoustic generator 132 which may include a piezoelectric device (or material) 161. In one embodiment, the acoustic system 130 may include more or fewer elements. For example, the acoustic system may include a plurality of (or two or more) acoustic cleavage circuits 144, each acoustic cleavage circuit configured to drive (or control) one or more acoustic generators 132. In one embodiment, the plurality of acoustic cleavage circuits may be configured to drive one or more piezoelectric devices (e.g., arrays thereof) (of one or more acoustic generators). Controlling multiple piezoelectric devices (and / or acoustic generators) is further described herein.

[0049] The acoustic system 130 includes a housing 151 or enclosure that houses at least some of the elements of the system 130. As shown, the housing 151 includes a low-voltage power supply 154, a signal generator 143, a high-voltage power supply 152, and an acoustic cleavage circuit 144. For example, the housing may be formed of any material such as metal, alloy, and / or plastic into which the elements can be coupled (or connected). In one embodiment, the housing may include one or more openings or access points that allow elements to be added and / or removed. In another embodiment, the housing may not include at least some of the elements shown herein. For example, the signal generator 143 may be a separate electronic device that can be coupled to the acoustic cleavage circuit 144 (for example, via one or more connectors of the housing 151). For example, the housing may include two connectors 157 and 158, which may be arranged to connect the acoustic generator to the acoustic cleavage circuit 144 with lead wires. In one embodiment, the connector may be any type of connector that can allow the connector of the acoustic generator to be detachably coupled to the housing 151. For example, connectors 157 and 158 may be banana jacks, which connect to the acoustic generator via banana plugs (of the generator). In another embodiment, the housing may include additional connectors, such as having one or more connectors that can be arranged to couple to a signal generator 143, which may be an external device, as described herein.

[0050] As described herein, the acoustic generator 132 may include one or more piezoelectric devices 161 that are driven by the acoustic system 130 and can vibrate (or operate) at high frequencies (e.g., 1 kHz to 100 MHz) to acoustically cleave a workpiece. In particular, the piezoelectric devices receive an amplified output signal S generated by the acoustic cleavage circuit 144. out It may be arranged to operate in one direction in response to a positive voltage cycle, S out It may be configured to act in a different direction in response to a negative voltage cycle. The driving of the piezoelectric device is further described herein.

[0051] In one embodiment, the low-voltage power supply 154 may be configured to provide power at a low voltage (below a voltage threshold) to operate one or more components of the system, such as the signal generator 143 and the acoustic cleavage circuit 144. For example, the low-voltage power supply may be a 24-volt (V) direct current (DC) power supply. In another embodiment, the low-voltage power supply may be configured to provide power at another voltage, such as a 12V power supply. The high-voltage power supply 152 may be configured to provide high-voltage (e.g., above a voltage threshold) DC power to one or more components of the acoustic system 130. In particular, the power supply 152 may have a positive voltage rail +V for supplying driving power to the acoustic generator 132. H and negative voltage rail-V H This includes, for example, a high-voltage power supply may be configured to provide a maximum voltage (e.g., per rail) from 0V to 20kV. In one embodiment, each rail may be in the range of -20kV to +20kV. In another embodiment, a high-voltage power supply may provide a maximum voltage from 3kV to 20kV. In some embodiments, the maximum voltage may be greater than 20kV. In one embodiment, the power supply may be configured to provide power over one or more voltages (e.g., over one or more voltage rails).

[0052] The signal generator 143 receives at least one input electrical signal S to drive the piezoelectric device 161. in The signal generator may be configured to provide one or more electrical signals. For example, the generator may be configured to provide multiple input signals for driving multiple piezoelectric devices of the acoustic generator 132. Driving multiple devices is further described herein.

[0053] In one embodiment, S incan be any type of signal that may include positive and negative cycles such as sine waves, square waves, etc. In one embodiment, the input signal can have a frequency of 1 Hz to 100 MHz. In another aspect, the input signal can have a period of 10 ns to 10 s. In another aspect, the input signal can include one or more electrical pulses that can be supplied at a specific frequency. In another aspect, the input signal can have a pulse width that varies between 10 ns and 10 s, and the period between each pulse can be in the range of 20 ns to 10 s. In another aspect, the acoustic splitting circuit 144 can be arranged to adjust S in as described further herein with respect to the acoustic splitting circuit.

[0054] In one embodiment, S provided by the signal generator 143 in can be used to resonate the piezoelectric device 161 of the acoustic generator 132 at a driving frequency that can be the same as the resonant frequency of the piezoelectric device, its harmonic frequencies, or other frequencies. In that case, S in can include (or have) a frequency at the resonant frequency of the piezoelectric device. How the input signal S in drives the acoustic generator is described further herein.

[0055] In one embodiment, the acoustic splitting circuit 144 can be arranged to drive the acoustic generator 132 (e.g., its piezoelectric device 161) in response to receiving the input signal S in from the signal generator 143. In particular, the acoustic splitting circuit can include an amplifier that generates S in for driving the piezoelectric device based on a series of pulses received from the signal generator (or based on S out received from the signal generator). For example, the acoustic splitting circuit can alternate the supply of current to the piezoelectric device 161 to operate the device, an amplified output signal S<This may include two switches in a push-pull amplifier configuration, a first (or bottom) switch 159 and a second (or top) switch 160, which can supply power. For example, S in During the positive cycle, the acoustic cleavage circuit is closed by switch 160 and opened by switch 159, thereby supplying +V to the acoustic cleavage circuit 144. H A first configuration may be one in which power is supplied to the piezoelectric device 161 from a high-voltage power supply 152 in or near thereto. In this case, the piezoelectric device 161 may extend (or be displaced) along one direction. However, S in During the negative cycle, the acoustic cleavage circuit opens switch 160 and closes switch 159, and -V is applied to the acoustic cleavage circuit. H Alternatively, a second configuration may be possible in which current is supplied from a low-voltage power supply 152 nearby. In this case, the piezoelectric device 161 may retract along the opposite direction from its elongated displacement (for example, it may return to its original position). In one embodiment, these two configurations may be repeated at high frequencies to cause the piezoelectric device 161 to vibrate back and forth. The acoustic cleavage circuit 144 is further described herein.

[0056] The acoustic system 130 also includes a controller 205 which may be configured to perform one or more operations. The controller 205 may be an application-specific integrated circuit (ASIC), a general-purpose microprocessor, a field-programmable gate array (FPGA), a digital signal controller, or a dedicated processor such as a set of hardware logic structures (e.g., filters, arithmetic logic units, and dedicated state machines). The controller is configured to perform operations for the system 130 to drive the piezoelectric device 161. Operations that may be performed by the controller are further described herein.

[0057] Controller 205 sends S to signal generator 143. inThe controller may be configured to control the signal generator by causing it to generate signals. The controller may be communicatively coupled to at least some elements of the system 130, such as the signal generator 143. In one embodiment, the controller may be a separate device from the signal generator and / or housing 151, or may be part of the housing and / or signal generator. In one embodiment, the controller may be configured to initiate the operation of the system 130, such as initiating the operation of switches 160 and 159 based on one or more conditions. For example, if the controller detects that the power supply 152 is powered on (e.g., switched on), it may cause the signal generator to initiate the operation of the switches. In one embodiment, the operation performed by the controller may be implemented in software (e.g., as instructions stored in memory and executed by either controller) and / or by hardware logic structures.

[0058] Figure 18 is another block diagram of the acoustic system 130 according to one embodiment. In particular, this figure shows an enlarged view of the acoustic cleavage circuit 144. As shown, the circuit includes several electronic components that are housed in, are part of, or can be arranged on the acoustic cleavage circuit 144. For example, the acoustic cleavage circuit 144 may include one or more printed circuit boards (PCBs) on which one or more of the components of the circuit are mounted and / or can be communicatively coupled.

[0059] The acoustic cleavage circuit 144 includes several isolators 174a-174c, several inverters 175a-175f, several gate drivers 177a and 177b, one or more capacitors 178a-178n (as capacitor bank 173), pairs of switches 159 and 160, a precharge circuit 201, and several terminals 180, 181, and 182. In one embodiment, the acoustic cleavage circuit 144 may include more or fewer components. For example, the acoustic cleavage circuit may include more inverters or fewer isolators. As another example, the circuit 144 may not include the precharge circuit 201.

[0060] The acoustic cleavage circuit 144 may include several components that can be comprised of one or more components described herein. For example, the acoustic cleavage circuit 144 includes a first (or bottom) drive circuit 171 that includes a signal path for driving switch 159, and a second (or top) drive circuit 170 that includes a signal path for driving switch 160. The circuit 144 receives an input signal from the signal generator 143, for example, S in The circuit includes an input signal drive circuit 183 that includes one or more signal paths based on the same. The circuit 144 also includes a push-pull circuit 172 that includes both switches 159 and 160 and can be coupled to a high-voltage power supply 152 via terminals 181 (positive voltage terminal) and 182 (negative voltage terminal). Each circuit may be illustrated as having a specific component of the circuit 144, but one or more circuits may include components of one or more other circuits.

[0061] Isolators 174a to 174c can be any type of isolator that can be designed to receive an electrical signal (or voltage) as input and pass (or transmit) at least a portion of the signal as output. In particular, the isolator can be any type (e.g., digital) isolator that can be positioned to electrically isolate one or more components of the acoustic system 130. As an example, isolator 174a can be positioned to isolate inverter 175a from signal generator 143. In one embodiment, the isolator may be an optical isolator that uses optical transmission to isolate two or more components in a signal path.

[0062] The inverters 175a to 175f can be any type of inverter that can be configured to receive an electrical signal and generate an inverted version of the electrical signal. For example, if the input signal is a sine wave, the inverter may apply a 180° phase shift. In one embodiment, at least some of the inverters may be inverting Schmitt triggers, which can be configured to pass the inverted version of the input signal as an output signal. In one embodiment, the Schmitt triggers may be designed to reduce noise from high-voltage swings and to reduce the feedback of transient currents caused by the push-pull circuit 172 to the input signal.

[0063] The gate drivers 177a and 177b can be any type of gate driver configured to receive an input electrical signal and, based on the input signal, generate an output drive signal (e.g., a voltage) to drive one or more switches.

[0064] As described herein, the push-pull circuit 172 may include switches 159 and 160 in a push-pull configuration. In particular, the switches may be any type of high-power switches designed to turn on and off at high frequencies based on an input signal to provide high power to a load, in which case the load may be one or more piezoelectric devices of the acoustic generator 132. In one embodiment, each of the switches may be of the same type. For example, switches 159 and 160 may be insulated-gate bipolar transistors (IGBTs). Specifically, both IGBTs may be n-channel transistors as shown. In another embodiment, the switches may be gallium nitride (GaN) field-effect transistors (FETs). In some embodiments, the switches may be any type of transistor. In one embodiment, a discharge circuit configuration may also be achieved using a resistor divider that monitors the voltage on a capacitor that triggers a Zener diode at a specific rail voltage based on the circuit configuration. This can result in a Zener diode triggering a silicon-controlled rectifier (SCR), which can transfer energy present on the capacitor bank to a piezoelectric device through a switch, and the switch's ON operation can be controlled via an optocoupler based on user input.

[0065] Here, we will describe the acoustic cleavage circuit 144 and the signal path of the input signal generated by the signal generator 143. As shown in the figure, the signal generator 143 may be coupled to the input signal drive circuit 183, which in turn receives the input signal S from the signal generator 143 to drive the push-pull circuit. inThe circuit can be configured to generate one or more input signals based on the following. In particular, circuit 183 includes an isolator 174a, which can be coupled to signal generator 143 (e.g., having an input terminal) and to inverter 175a (e.g., having an output terminal), and inverter 175a can also be coupled to inverter 175b. The input signal drive circuit 183 can be coupled to both drive circuits 170 and 171, creating at least two signal paths, one for each of the drive circuits, as follows: In particular, inverter 175a can be coupled to drive circuit 170 and to inverter 175d. In addition, inverter 175d can be coupled to drive circuit 171. Thus, inverter 175a can be coupled between signal generator 143 and drive circuit 170, while both inverters 175a and 175d can be coupled between signal generator 143 and drive circuit 171. As a result, the drive circuit 170 receives S from the signal generator 143 via the input signal drive circuit 183. in An inverted version of this can be received, while the drive circuit 171 is S in It can receive an inverted version of (e.g., the original input signal). For example, the signal generator 143 can receive an analog or digital (DC) signal, or an S-wave such as a square wave digital (DC) signal. in It may be configured to generate. The acoustic cleavage circuit 144 may be arranged to receive an input signal from the signal generator 143 (for example, through coupling with the signal generator 220). In particular, the isolator 174a is S in The inverter 175a may receive the input signal and pass or transfer at least a portion of it to the inverter 175a, which may perform a 180° phase shift to provide the phase-shifted signal to the drive circuit 170 and inverter 175d. The inverter 175d may perform another 180° phase shift to provide the drive circuit 171 with the unphase-shifted input signal (e.g., the original input signal, or a version of the original input signal received from the signal generator 143).

[0066] As shown in the figures, both drive circuits 170 and 171 can be coupled between the input signal drive circuit 183 and the push-pull circuit 172. In particular, drive circuit 171 can be coupled to switch 159, and drive circuit 170 can be coupled to switch 160. Both drive circuits can have the same configuration and the same components (e.g., coupled in series) because both drive circuits receive input signals that are phase-shifted relative to each other. For example, drive circuit 171 may include inverter 175e which can be coupled between inverter 175d and isolator 175c, and isolator 174c may be coupled to another inverter 175f which can be coupled to gate driver 177b. Drive circuit 170 may include inverter 175b which can be coupled between inverter 175a and isolator 174b, and isolator 174b may be coupled to inverter 175c which can be coupled to gate driver 177a.

[0067] In one embodiment, having the same configuration, both drive circuits may drive their respective switches with a phase difference. For example, drive circuit 170 may be configured to generate a drive signal that may be an inverted version of the input signal from the signal generator for driving switch 160, while drive circuit 171 may be configured to generate a drive signal that may be an uninverted version of the input signal for driving switch 159.

[0068] The push-pull circuit 172 can be coupled to both the drive circuits 170 and 171 and to the high-voltage power supply 152. In particular, the gate of the first switch 159 can be coupled to the drive circuit 171, and the emitter of the switch 159 can be positioned to provide a negative voltage rail-V of the high-voltage power supply 152. H The negative terminal 182 can be coupled to the switch 160. Similarly, the gate of the second switch 160 can be coupled to the drive circuit 170, and the collector of the switch 160 can be coupled to the positive voltage rail +V of the high-voltage power supply 152, which can be positioned to provide a positive voltage supply. H Positive terminal 181 which can be coupled

[0069] Each of the switches can be coupled together. In particular, the collector of the first switch 159 can be coupled to the emitter of the second switch 160 via the output terminal 180 of the push-pull circuit 172. In addition, the acoustic cleavage circuit 144 can be coupled to the acoustic generator 132 via at least some of its terminals. In particular, the acoustic generator 132 can be coupled to the output terminal 180 and the negative terminal 182. In addition, a capacitor bank 173, which may include one or more capacitors 178a to 178n, can be coupled in parallel to the push-pull circuit 172. In particular, the capacitor bank 173 can be coupled to the high-voltage power supply 152 via terminals 181 and 182. In one embodiment, the capacitors can be any type of capacitor (e.g., ceramic, film, etc.) that can be rated for high voltages, such as a maximum rating of 20kV. In particular, the capacitors can be rated for the output voltage of the voltage source 152 that can be applied across the push-pull circuit 172. In one embodiment, each of the capacitors can be a capacitor of the same type. In another embodiment, each capacitor may have a capacitance in the range of 5nF ​​to 500mF.

[0070] As described herein, the push-pull circuit receives one or more input signals from drive circuits 170 and 171 and, in response, an amplified output signal S for driving the acoustic generator 132 out This could be an amplification circuit that can be arranged to generate (at output terminal 180). For example, drive circuits 170 and 171 may be provided with an input signal S provided by a signal generator 143 which may have negative and positive cycles oscillating at high frequencies. in Upon receiving an input signal based on the above, switches 159 and 160 may be driven to open and close in a push-pull manner to supply high power from power supply 152 to the acoustic generator, and capacitor bank 173 may provide energy during amplifier operation to reduce voltage drop due to piezoelectric material load.

[0071] Circuit 144 also includes a precharge circuit 201 which can be coupled between the capacitor bank 173 and a high-voltage power supply (e.g., terminal 181). The precharge circuit 201 may be configured to charge the capacitor bank before the push-pull circuit 172 generates an amplified output signal for driving the piezoelectric device 161. In particular, the circuit 201 may limit the current drawn by the capacitor bank 173 from the power supply 152 when the capacitor bank is being charged from a discharged state, such as when the circuit is first started. The precharge circuit 201 includes a relay 200 in parallel with relay 202 and a resistive element 203, such as one or more resistors. In one embodiment, the circuit 201 may include one or more other electronic elements, such as a capacitor and / or an inductor. When circuit 144 is in the first (or initial) configuration, relay 200 may be in an open state and relay 202 may be in a closed state, thereby causing the resistive element 203 to be in series with the capacitor bank. In one embodiment, the circuit may remain in this initial configuration for a period of time until the capacitor bank reaches the same voltage as the power supply 152. In one embodiment, this first configuration may occur when the circuit is first activated and / or while the capacitor bank 173 is not fully charged (discharged). As a result, the capacitor bank may be charged without drawing a significant amount of current (e.g., infinite current) from the power supply due to the resistive element 203. Limiting the current during the charging period may prevent damage to the circuit configuration and components of the circuit 144. In one embodiment, the first configuration may occur during a predetermined period, such as the time constant of the circuit 144. After that period, the circuit 144 may switch to a second (e.g., active) configuration in which relay 200 is closed and relay 202 is open, thereby connecting the capacitor bank 173 to terminal 181 and allowing the circuit 144 to drive the piezoelectric device 161. In one embodiment, relays 200 and 202 may be controlled by one or more control circuits (not shown).

[0072] In one embodiment, the configuration of circuit 144 may be controlled by a controller 205. In this case, the controller may be communicatively coupled to relays 200 and 202 and may be configured to control the relays based on which configuration circuit 144 is operating.

[0073] As described above, the acoustic system 130 may be configured to drive a piezoelectric device 161 of the acoustic generator 132, which may be used to create a depression on the workpiece to facilitate fracture of the workpiece. In another embodiment, the system 130 may be configured to drive multiple (e.g., similar or different) piezoelectric devices to cleave a workpiece. In particular, the system may control multiple piezoelectric devices to create depressions to facilitate fracture and to provide controlled crack propagation along the workpiece. For example, the system 130 may control one or more arrays of piezoelectric devices (e.g., in a manner at least partially sequential) to initiate and form (or propagate) a crack along a path in the workpiece. For example, an array of piezoelectric devices may be controlled in a manner at least partially sequential to create a crack along a path that may coincide with an arrangement of the array of piezoelectric devices. Figures 19–21 provide example block diagrams of the acoustic system 130 that can drive multiple piezoelectric devices.

[0074] Referring to Figure 19, this figure shows a block diagram of an acoustic system 130 for driving multiple piezoelectric devices 161 and 161' of an acoustic generator 132 according to one embodiment. As shown, the system 130 includes multiple signal generators 143 and 143' and multiple power supplies 152 and 152'. Each of the signal generators receives one or more input signals S for driving one or more piezoelectric devices. in and S in It is generating '. For example, as shown in the figure, S in This can be used to drive the piezoelectric device 161, S in' may be used to drive piezoelectric device 161'. Each of the high-voltage power supplies may be configured to supply one or more output voltages to drive one or more piezoelectric devices. In particular, each of the power supplies may supply power at the same voltage or at different voltages. For example, power supply 152' is rail +V H 'and -V H Power is supplied via ', and those rails are +V H and -V H The power supply 152 that provides power may be supplied with a different voltage. In one embodiment, the system 130 may drive one or more piezoelectric devices with different voltages for various reasons. For example, different voltages may result in differences in the displacement of the piezoelectric devices. For example, one voltage may displace one piezoelectric device more than another voltage applied to another piezoelectric device. In another embodiment, different piezoelectric devices may be rated differently, for example, some of them may require one output voltage to be driven, while one or more other devices may require different output voltages. In one embodiment, it may also be possible to control the amount of stress introduced to the crack tip and the crack velocity by applying a fluctuating voltage.

[0075] As illustrated, the power supplies 152 and 152' and the signal generators 143 and 143' may be separate (independent) electronic devices. In another embodiment, at least some of the devices may be (or form) part of a single electronic device. For example, although the power supplies 152 and 152' are shown as separate blocks, they may be part of a single power supply. In that case, the power supply of system 130 may provide one or more output voltages across multiple pairs of positive and negative rails. In another embodiment, the signal generator may be part of a single generator.

[0076] The cleavage circuit 144 receives the input signal S from the signal generator. in and S in In response to ', the output signal S out and S out' may be arranged to drive two (or more) piezoelectric devices 161 and 161'. In particular, the cleavage circuit 144 includes several switches in some push-pull configurations. For example, together with switches 159 and 160, the cleavage circuit 144 outputs signal S out The system includes switches 159' and 160' in a push-pull configuration for driving device 161. In this case, each signal generator may be configured to drive the switches in a push-pull configuration (e.g., a push-pull circuit) to provide output voltages from the respective high-voltage power supplies of the switches to their respective piezoelectric devices. Thus, the system 130 enables cleavage propagation based on how devices 161 and 161' are controlled.

[0077] Therefore, system 130 allows several piezoelectric devices to be driven, and the devices may be the same (e.g., similarly rated) or different. In particular, as described herein, the elements of system 130 may be configured to drive different piezoelectric devices over different output voltages, which also allows for variations in how the devices are controlled. As a result, the system may provide better control of crack propagation.

[0078] Figure 20 is another block diagram of an acoustic system 130 for driving a plurality of piezoelectric devices 161 and 161' according to one embodiment. As shown, the system 130 includes at least some of the components shown in Figure 18. For example, the system 130 includes a high-voltage power supply 152 including two pairs of positive and negative rails for supplying one or more output voltages to a cleavage circuit 144. The system 130 includes two signal generators 143 and 143', a cleavage circuit 144, and an acoustic generator 132.

[0079] As illustrated, the cleavage circuit 144 includes at least several replicated components illustrated in Figure 18 for driving piezoelectric devices 161 and 161'. In particular, the circuit 144 includes push-pull circuits 172 and 172' coupled to piezoelectric devices 161 and 161', respectively, each push-pull circuit for driving its respective piezoelectric device with power (output voltage) supplied by power supply 152. In particular, the additional push-pull circuit 172' includes push-pull switches 159' and 160', where switch 159' is driven by drive circuit 171' and switch 160' is driven by drive circuit 170'. In one embodiment, the switches in push-pull circuit 172' may be of the same type as the switches in circuit 172. In another embodiment, they may be different. For example, the pair of switches in either circuit may be based on the ratings (e.g., power requirements) of the piezoelectric device being driven by the switch in a push-pull configuration. In addition, the input signal drive circuit 183' receives the signal S from the signal generator 143'. in ' receives the signal and then two signals (one of which is S in ' is in phase with the other, S in The signal can be split into (and phase-shifted) and arranged to provide the signal to the drive circuits 170' and 171'. In addition, circuit 172' includes several terminals, the first terminal 182' is a negative voltage rail -V H The second terminal 181' can be coupled to the positive voltage rail +V H 'Connected to terminal 180', the device is S out To provide ', switches 159' and 160' can be coupled to the piezoelectric device 161'.

[0080] As shown in the figure, the push-pull circuits 172 and 172' can be coupled (in parallel) to capacitor banks 173 and 173', respectively. In one embodiment, the capacitor banks may be rated similarly. In another embodiment, they may be rated differently based on the power output from the power supply 152 that can be drawn by each of the push-pull circuits of the capacitor banks. In particular, the capacitor banks may be based on the output voltage between their terminals. For example, based on the output voltage of the power supply 152, capacitor bank 173 (or the capacitors in the bank) may have one capacitance, while capacitor bank 173' may have a different capacitance.

[0081] In one embodiment, the system 130 may drive the piezoelectric devices 161 and 161' in similar or different ways. For example, both devices may be driven with similar (or the same) output signals (e.g., at the same driving frequency) so that both devices oscillate in substantially similar ways and / or for similar (or the same) periods. In another embodiment, the piezoelectric devices may be driven differently. For example, both devices may be driven according to different (or similar) power levels (e.g., based on their respective input signals, S out and S out They can be driven to oscillate differently (according to different driving frequencies). In addition, both devices can be driven for different periods. In particular, signal generators 143 and 143' can be arranged to drive the push-pull circuits 172 and 172' independently, for periods that at least partially overlap or do not overlap. For example, signal generator 143 may drive device 161 in a first period, while signal generator 143' may drive device 161' in a second period that does not overlap with the first period.

[0082] As described herein, system 130 may be configured to drive multiple piezoelectric devices. In one embodiment, the system may be configured to drive two or more devices, each device may be driven using at least some duplicated components of Figure 17. In particular, each piezoelectric device may be driven by its own push-pull circuit having a (e.g., dedicated) switch that operates in a push-pull configuration. In another embodiment, at least some of the circuit configurations of the cleavage circuit may be configured to drive multiple piezoelectric devices. For example, two or more push-pull circuits may share a common circuit configuration (e.g., at least one switch) for driving multiple piezoelectric devices. Such a design may allow for a more compact circuit configuration of system 130, thereby reducing the complexity and cost of the system. Figure 21 illustrates an example block diagram of an acoustic system for driving several piezoelectric devices.

[0083] Referring to Figure 21, this figure shows an acoustic system 130 configured to drive multiple piezoelectric devices 161 and 161' using a common (shared) circuit configuration. In particular, this figure shows that a cleavage circuit 144 can be coupled to the piezoelectric device 161, and S out The specification includes a push-pull circuit 172 which includes a pair of switches, switches 159 and 160, that can be arranged to drive the device. As described herein, the push-pull circuit 172 may be coupled to a piezoelectric device 161 via an output terminal 180. In addition, the circuit 172 may be coupled to a power supply 152 via terminals 181 and 182.

[0084] The cleavage circuit also includes another push-pull circuit 172' having a second pair of switches 160 and 159', which can be coupled to the piezoelectric device 161, S out The device may be configured to be driven using '. Specifically, the push-pull circuit 172' includes an output terminal 180 coupled to both switches 160' and 159 and coupled to the piezoelectric device 161'. The push-pull circuit 172' also has rail +V through terminals 181' and 182'.H 'and -V H The emitter of switch 159 may be coupled to both terminals 182 and 182'. As shown in the figure, both push-pull circuits share switch 159 as a common switch (for example, coupled to both negative rails of power supply 152). As described herein, the cleavage circuit 144 may be configured to operate at least some of the switches in different push-pull configurations to drive one or more piezoelectric devices based on an input signal from signal generator 143. The operation of the cleavage circuit 144 is further described herein.

[0085] As illustrated, the cleavage circuit 144 includes at least several electronic components as described herein. For example, the circuit 144 includes a first drive circuit 171 coupled between switch 159 and signal generator 143, and a second drive circuit 170 coupled between switch 160 and signal generator 143. The circuit 144 also includes another drive circuit 170' which may be coupled between switch 160' and signal generator 143. Both capacitor banks 173 and 173' may be coupled to the terminals of their associated push-pull circuits. For example, capacitor bank 173 may be coupled to terminals 181 and 182, while capacitor bank 173' may be coupled to terminals 181' and 182'.

[0086] The signal generator 143 may be configured to control the push-pull circuits 172 and 172' to drive their respective piezoelectric devices. In one embodiment, the generator 143 may drive the piezoelectric devices during non-overlapping periods. For example, as described herein, during a first period, the signal generator 143 controls switches 159 and 160 to draw power from the power supply 152, S out To drive the piezoelectric device 161 in a push-pull manner using the following input signals S in and S in' can be supplied to the drive circuits 171 and 170. In one embodiment, both input signals may be the same or different. For example, S in ' is, S in This could be a phase-shifted version. In particular, both input signals may oscillate with a phase shift between positive and negative cycles at a given frequency.

[0087] During the second period that follows (and / or does not overlap with) the first period, the signal generator 143 will in Stop generating at least one of the input signals such as ' and input signal S in and S in " may begin to provide the drive circuits 171 and 170'. In that case, switches 159 and 160' will (for example, rail + V H 'and -V H ') draws power from S out To drive device 161 using ', it can operate in a push-pull configuration. Thus, signal generator 143 can generate pairs of input signals at different time intervals to drive different pairs of switches in a push-pull configuration. In one embodiment, S in is, S in 'and S in This could be a version in which one or both of the input signals are out of phase. In another embodiment, each pair of input signals may be different from or similar to each other. In this case, the signal generator may drive different piezoelectric devices at different driving frequencies based on the input frequencies of the input signals.

[0088] In another embodiment, the signal generator 143 may be configured to drive one or more of the piezoelectric devices 161 and 161' using this configuration for at least partially overlapping periods. In this case, the signal generator is configured to drive the switches 159, 160, and 160' simultaneously with the input signal S in S in 'and S inThis can generate (for example, a switch receives drive signals simultaneously from each of its drive circuits). This makes it possible to control multiple (similar or different) piezoelectric devices at any given time to propagate a crack, as described herein.

[0089] As a result, this design may allow for multiple pairs of switches, each pair of switches may share a common switch that operates during periods when they overlap or do not overlap in a push-pull configuration.

[0090] In one embodiment, one or more of the examples described herein may include one or more pre-charge circuits, such as circuit 201 for pre-charging one or more capacitors. For example, a pre-charge circuit (and relay) may be coupled between capacitor bank 173' and terminal 181'. In one embodiment, each of the pre-charge circuits may be configured to charge their respective capacitor banks for the duration that circuit 144 is activated, as described herein. As a result, pre-charging may occur during each startup of the equipment or tool, as described herein.

[0091] As previously described, the acoustic system 130 can drive the piezoelectric device by causing the device to vibrate back and forth at high frequencies. When the piezoelectric device vibrates at frequencies other than its resonant frequency, more power is required to drive the device. In particular, when the piezoelectric device is driven at frequencies other than its resonant frequency, the device becomes inactive, and as a result, more power is required to drive the device more strongly. To optimize energy transfer and thereby require less drive voltage from the power supply to the piezoelectric device, the device may be driven at its resonant frequency. The following embodiments include examples in which the piezoelectric device is driven at its resonant frequency and / or overtones (e.g., multiples of its resonant frequency) to optimize the power transferred to the device.

[0092] Referring to Figure 22, this figure includes a block diagram of an acoustic system 130 capable of driving a piezoelectric device 161 at its resonant frequency to optimize power transfer. System 130 includes a power supply 210, a power factor correction (PFC) circuit 211, an AC-to-DC converter 212, a power converter 214, a function generator (or signal generator) 215, an amplifier 216, and an acoustic cleavage system 213 including the piezoelectric device 161. In one embodiment, the acoustic system 130 may include fewer or more components. For example, the PFC circuit 211 may be an optional circuit. In another example, system 130 may include one or more acoustic cleavage systems 213, each of which may be used to drive one or more piezoelectric devices. Multiple acoustic cleavage systems are further described herein.

[0093] Power supply 210 may be an AC power supply that can be configured to supply AC power (e.g., high AC voltage) to a load. In one embodiment, power supply 210 may be an AC mains power supply or a converter such as a DC-AC converter designed to convert DC power to AC power. PFC circuit 211 may be coupled between the AC power supply 210 and the AC-DC converter 212 and may be configured to receive AC power and correct the power factor of the AC voltage supplied by the AC power supply. In one embodiment, the PFC circuit may be an active or switching circuit that uses one or more active devices such as power switches to correct the power factor. In another embodiment, the PFC circuit may be a passive circuit that uses non-active electronic components such as diodes and capacitors to correct the power factor of the supplied AC power. In one embodiment, the PFC circuit 211 may be configured to maintain a power factor of 0.9 or about 0.9. The AC-DC converter 212 may be coupled to the AC power supply 210 and may be configured to convert the AC voltage supplied by the AC supply unit to a DC voltage. If system 130 does not include the PFC circuit 211, the converter 212 may be coupled to an AC power source. In another embodiment, the converter 212 may be coupled to the PFC circuit 211 and may convert the AC power supplied by the circuit 211.

[0094] The power converter 214 may be coupled between the converter 212 and the amplifier 216 and may be configured to convert the DC voltage supplied by the converter 212 to another DC voltage (e.g., a drive voltage) for driving the piezoelectric device 161. In one embodiment, the drive voltage may be a voltage predetermined based on the specifications of the piezoelectric device. In one embodiment, the power converter may include at least one of buck, boost, and buck / boost converters, which may be designed to generate an output DC voltage by increasing and / or decreasing the input DC voltage supplied by the converter 212. For example, the converter 214 may apply a gain to the DC voltage supplied by the converter 212 to increase (e.g., boost) or decrease (e.g., buck) the input voltage from the AC-DC converter. In one embodiment, the power converter 214 may be an isolated converter including an input stage and an output stage, and current may not flow between the two stages. The converter may be isolated using a transformer that separates the two stages (e.g., flyback or forward mode). In another embodiment, the power converter 214 may be a non-isolated converter, in which case current can flow between the input and output stages. Examples of non-isolated converters may include boost or buck converters. In one embodiment, the non-isolated converter may not use a transformer to boost the input DC voltage. In one embodiment, the power converter may include electronic equipment that enables the converter to generate a desired DC voltage based on the input DC voltage. For example, the converter may include control electronic equipment (e.g., a microcontroller), a pulse width modulator, and other power converter components (e.g., a transformer in the case of an isolated topology).

[0095] The function generator 215 receives an input signal for driving a piezoelectric device, for example, S in It can be configured to generate. As described herein, device 161 may be driven at its resonant frequency to optimize the input power. In that case, the input signal generated by the function generator may be at (or may have) the resonant frequency of the piezoelectric device. In another embodiment, S inS may have harmonic frequencies of the resonant frequency of the piezoelectric device. For example, if the resonant frequency of device 161 is 100 kHz, in The frequency may be defined as 100kHz, 200kHz, 300kHz, etc., which may enable efficient driving of device 161. In one embodiment, the frequency of the input signal may be set by the user, for example, via an input device which may be coupled to a function generator. In one embodiment, S in This can be any type of input signal, such as a sine wave or a square wave.

[0096] In one embodiment, the function generator 215 may be coupled to an AC power supply 210 and draw power from the AC power supply 210. In this case, the function generator is powered using the supplied AC voltage. Instead of drawing power from the AC power supply, or in addition to that, the function generator may (optionally) be coupled to a power converter 214 and powered by the converter. In this case, the converter 214 may be configured to generate different DC voltages for the function generator. In particular, the converter 214 may generate a first DC voltage for driving a piezoelectric device and a second DC voltage for supplying power to the generator 215. In one embodiment, the second DC voltage may be smaller than the first DC voltage.

[0097] The amplifier 216 may be coupled to the AC-DC converter 212, the function generator 215, and the piezoelectric device 161, and the amplifier receives the input signal S from the function generator according to the DC voltage that can be supplied by the converters 212 and / or 214. in By amplifying the output signal, for example, S out Generate S out It can be arranged to drive a piezoelectric device using S inThe signal is amplified. In this case, the amplifier may be an operational amplifier configured to generate an output signal (e.g., a sine wave, a square wave, etc.) to apply -V (e.g., 0 volts) and +V across the piezoelectric device 161. The function generator controls the amplifier to modify the input signal, while the DC power drawn by the amplifier may be controlled by the converter 214. As a result, the switching of the DC voltage by the amplifier may occur at the resonant frequency of the piezoelectric device, thereby S out This is at the resonant frequency of device 161. In one embodiment, the amplifier is S according to the DC power drawn from the converter 214. in It may be a voltage amplifier that increases the amplitude. In one embodiment, the amplifier may be a single (e.g., operational) amplifier. In another embodiment, amplifier 216 may be a bridge amplifier that uses two or more operational amplifiers to amplify the input signal. As a result, the acoustic system 130 may be designed to drive the piezoelectric device at its resonant frequency, thereby maximizing the power to the device 161.

[0098] As shown herein, the acoustic system 130 may be configured to power an acoustic cleavage system 213 to drive a piezoelectric device 161. In one embodiment, the system may include one or more acoustic cleavage systems 213, each of which may be powered by a power supply 210. In this case, each acoustic cleavage system may draw power from the power supply and be configured to drive one or more piezoelectric devices. In one embodiment, each acoustic cleavage system may drive its respective piezoelectric device according to its respective resonant frequency and / or with a different DC voltage. For example, each system 213 may include a power converter that can be designed to generate a specific DC voltage that can be applied across its respective piezoelectric device. As a result, each amplifier in each acoustic cleavage system may draw a specified DC power to drive each piezoelectric device in the system at the resonant frequency of its respective piezoelectric device.

[0099] This system 131 allows multiple piezoelectric devices to be driven (for example, simultaneously) using a common power supply. Such a configuration having multiple cleavage systems 213 requires one or more amplifiers for each system. In another embodiment, the piezoelectric devices may be driven by a single amplifier, thereby reducing the footprint of the electronic components of system 130. Figure 23 illustrates an example of driving piezoelectric devices using an amplifier.

[0100] Referring to Figure 23, this figure shows another block diagram of an acoustic system 130 which may be configured to drive multiple piezoelectric devices using (for example, a single) amplifier 216. The system includes a power supply 210, a PFC circuit 211, an AC-DC converter 212, a power converter 214, a frequency selector circuit 219, an amplifier 216, several (or more) switches 221, several (or more) piezoelectric devices 161, and a controller 205. In one embodiment, the system may include more or fewer components. For example, as shown, the system 130 may be configured to drive two piezoelectric devices 161 and 161' (at least one of them), each of which may be coupled to the amplifier 216. In another embodiment, the system may include more than two piezoelectric devices which may be individually driven by the system as described herein. In another embodiment, the system may not include the PFC circuit 211.

[0101] System 130 may be configured to drive one or more piezoelectric devices. As described herein, amplifier 216 may be configured to drive one of the piezoelectric devices 161 and 161' at a time (e.g., over non-overlapping periods). The amplifier may drive a particular device based on the (e.g., open or closed) state of switches 221 and 221', and / or at least one of the input signals received from the frequency selector circuit. Driving the amplifier is further described herein.

[0102] A (first) switch 221 may be coupled between a first piezoelectric device 161 and an amplifier 216, and a (second) switch 221' may be coupled between a second piezoelectric device 161' and an amplifier 216. In particular, each of the switches is coupled to a negative voltage line to their respective piezoelectric devices. For example, switch 221 couples the negative voltage terminal of the amplifier to the corresponding negative voltage terminal of device 161. In another embodiment, one (or both) of the switches may be coupled to a positive voltage line that couples the amplifier to its respective piezoelectric device.

[0103] In one embodiment, switches 221 and 221' can each be any type of high-power switch that can be switched between an open state and a closed state at a high frequency. Examples of high-power switches include IGBTs, GaN FETs, and metal-oxide-semiconductor (MOS) FETs.

[0104] Controller 205 may be communicatively coupled to switches 221 and 221', and may be configured to close (close) either of the switches to allow amplifier 216 to drive its respective piezoelectric device. For example, to drive device 161, the controller may close switch 221, thereby coupling the amplifier's negative voltage line to piezoelectric device 161, allowing the amplifier to apply voltage across piezoelectric device 161. In addition, controller 205 may open switch 221' to disconnect the amplifier's negative voltage line from piezoelectric device 161'. In particular, while switch 221 is closed and switch 221' is open, the function generator of system 130 may cause the amplifier to generate a first input signal to generate a first output signal over +V and -V. Conversely, to drive device 161', the controller may close switch 221' and open switch 221. In this case, the function generator may provide a second (different) input signal to the amplifier at the resonant frequency of device 161', and the amplifier generates a second output signal over +V' and -V' to drive device 161'. In one embodiment, the controller 205 may be part of system 130, or it may be an external controller that is not part of the system but can be communicatively coupled to one or more of the switches.

[0105] The frequency selector circuit 219 may be coupled to the power converter 214, amplifier 216, and controller 205 and may be configured to drive one or more piezoelectric devices at a given frequency. In particular, the frequency selector circuit may be configured to provide an input drive signal to the amplifier to drive at least one of the piezoelectric devices of system 130. In one embodiment, the controller 205 may be configured to cause the frequency selector circuit to generate a specific input signal at the frequency of each piezoelectric device, which may be amplified by the amplifier 216 as described herein.

[0106] Referring to Figure 24, this figure illustrates a block diagram of a frequency selector circuit 219 that may be designed to drive one or more piezoelectric devices through a single amplifier 216. As shown, the frequency selector circuit 219 includes a plurality of function generators 240 and 240' and a plurality of switches 241 and 241'. In one embodiment, the selector may include more or fewer components as shown. In one embodiment, the frequency selector may include several components that enable the selector to drive the same or fewer number of piezoelectric devices. The function generators may be coupled to the amplifier 216 via their respective switches.

[0107] In one embodiment, each of the function generators may be configured to generate a specific input signal for driving a particular piezoelectric device (or one or more devices) at a specific resonant frequency of the device. Function generators for driving a particular piezoelectric device are further described herein. Although illustrated as separate function generators, the frequency selector circuit may include function generators (or electronic components) that can be configured to generate two or more input signals, as described herein. Each of the function generators 240 and 240' receives its respective DC voltage from the power converter 214. In particular, generator 240 receives the first DC voltage V dc The second function generator 240' receives the second DC voltage V dc The power converter receives the following. In one embodiment, these voltages may be the same or different. For example, each function generator may draw different amounts of power from the converter based on the input signal generated by the generator. In another embodiment, the power converter 214 may generate only one or more voltages for one or more function generators in order to operate at any given time. For example, a controller (e.g., controller 205 or the controller of the power converter) may receive the following: dc 'not V dcThe function generators 240 and 240' can be configured to generate and drive only the input signal, and for the function generator 240 to generate the drive signal instead of the function generator 240' (for example, based on user input). This ensures that only the function generator generates the output signal for driving the corresponding piezoelectric device. As described herein, each of the function generators 240 and 240' can generate an input signal at a frequency corresponding to the corresponding resonant frequency of the respective piezoelectric device that the generator drives. For example, if the function generator 240 is for driving piezoelectric device 161, the generator can generate an input signal at the resonant frequency of device 161.

[0108] Each of switches 241 and 241' can be coupled between the respective function generators 240 and 240' and the amplifier 216. For example, each switch may include an input (terminal) that can be coupled to the output of the respective function generator, while the output of each switch can be coupled together to the input of the amplifier. In one embodiment, switches 241 and 241' may be low-power and high-frequency switches such as MOSFETs. In particular, since the input signal generated by the function generator may provide less power than the drive signal generated by the amplifier 216, the switches may be able to operate with less power than switches 221 and 221'.

[0109] The controller may be configured to cause the frequency selector circuit 219 to output a single input signal generated by a function generator at any given time. In particular, the controller 205 may be communicatively coupled to each of switches 241 and 241' and configured to control the state of each switch (e.g., open or closed). Specifically, the controller may be configured to close switches corresponding to function generators that drive one or more piezoelectric devices. For example, a function generator may be arranged to drive device 161. In that case, the controller may be configured to close switch 241 and open switch 241' when function generator 240 drives device 161. When switch 241 is closed, the input signal generated by function generator 240 may be passed to amplifier 216.

[0110] Returning to Figure 23 and continuing the previous example, when driving device 161, the controller 205 may be configured to close switch 221 and open switch 221', while the amplifier 216 may drive the electrical device 161 by applying voltages +V and -V according to the input signal received from the frequency selector circuit 219 (for example, from the function generator 240).

[0111] In one embodiment, the controller 205 may dynamically adjust the states of switches 221 and 241 based on which piezoelectric device the system 130 is driving. In some embodiments, to determine which device to drive, the controller 205 may be configured according to user input and / or by a cleavage algorithm performed by the controller.

[0112] Figure 25 is a block diagram of an acoustic system 130, which includes a radio frequency (RF) amplifier 250 for driving a piezoelectric device 161, according to one embodiment.

[0113] The system 130 includes an AC power supply 210 for supplying AC voltage, a piezoelectric device 161 including a resonant frequency, an RF amplifier 250 which can be coupled to the AC power supply and the piezoelectric device, a function generator 252, and a matching circuit 251.

[0114] The function generator 252 may be coupled to an RF amplifier and configured to cause the RF amplifier to generate an output signal based on an AC voltage for driving a piezoelectric device, the output signal having a frequency at the resonant frequency of the piezoelectric device. In particular, the generator 252 may be designed to generate an input signal, as described herein. In one embodiment, the signal generated by the generator 252 may be an RF signal having a frequency within the RF frequency spectrum (e.g., 20 kHz to several hundred GHz). In one embodiment, the function generator may be a sweep generator configured such that the switching frequency of the system aligns with the resonant frequency of the piezoelectric device. For example, differences between piezoelectric devices (e.g., manufacturing, materials, etc.) may result in different resonant frequencies. As a result, the resonant frequencies between devices may be shifted (e.g., by 1 kHz or more) from the expected resonant frequency. In such cases, the sweep generator may be configured to perform a frequency sweep around the expected resonant frequency to determine a target resonant frequency of the piezoelectric device. For example, the sweep generator may generate a frequency sweep signal having a frequency that varies over a frequency range that may include the expected resonant frequency of the piezoelectric device. Therefore, a sweep generator can drive a piezoelectric device over one or more frequencies over a period of time. Based on the frequency sweep, the sweep generator can determine a target resonant frequency of the piezoelectric device within a frequency range. In one embodiment, the target resonant frequency may correspond to the maximum possible power that a particular piezoelectric device can deliver. In that case, to determine the target resonant frequency, system 130 may monitor the power drawn by the piezoelectric device to determine which frequency in the frequency sweep corresponds to the maximum power drawn by the piezoelectric device. In one embodiment, once the target resonant frequency is determined, the function generator may be configured to generate a drive signal at the target resonant frequency, as described herein. Such operation may be performed in a controlled environment (e.g., a laboratory).

[0115] The RF amplifier 250 may be coupled to an AC power supply 210 and a function generator 252 and may be configured to convert an input signal, which may be a low-power signal, into a high-power RF signal according to the AC power supplied by the power supply 210. In one embodiment, the RF amplifier 250 may be any type of RF power amplifier, such as a Class A amplifier or a Class B amplifier.

[0116] A matching circuit 251 may be coupled between the RF power amplifier 250 and the piezoelectric device 161, and may be designed so that the input impedance of the piezoelectric device 161 matches the output impedance of the amplifier 250 (e.g., the output terminal of the amplifier 250). In particular, the matching circuit is designed so that the output terminal of the RF amplifier sees the input impedance of the piezoelectric device 161, which may be in the range of 45 ohms to 50 ohms. In another embodiment, the input impedance may be in the range of 47 ohms to 50 ohms. In one embodiment, the input impedance may include the impedances of the piezoelectric device and / or the electronic components of the matching circuit. As a result, the matching circuit 251 allows the combined input impedance of the piezoelectric device and the matching circuit to be equal to the output impedance of the RF amplifier, thereby minimizing reflections in the circuit and allowing maximum power to be delivered from the RF amplifier to the piezoelectric device at its resonant frequency.

[0117] In one embodiment, a matching circuit or equipment impedance matching network (EIMN) may include several electronic components, such as one or more inductors and / or one or more capacitors, which may be connected in different topologies such that the electrically inductive reactance of the matching circuit at the resonant frequency (or target resonant frequency) of the piezoelectric device can cancel out the electrically capacitive reactance of the piezoelectric device. In one embodiment, the inductors and / or capacitors may convert the resistance at the output of the RF amplifier into the resistance of the piezoelectric device at its resonant frequency.

[0118] In another embodiment, the matching circuit 251 may include one or more (e.g., step-up) transformers, each having an additional parallel inductance on its secondary side, which can cause the capacitive reactance of the piezoelectric device to resonate at its resonant frequency. In some embodiments, the turns ratio of the transformers may be selected to convert the resistance at the output of the RF amplifier 250 to the resistance of the piezoelectric device at its resonant frequency.

[0119] In some embodiments, system 130 may include additional components for driving multiple piezoelectric devices. As shown, system 130 includes additional (optional) components for driving piezoelectric device 161'. In particular, it includes an additional RF amplifier 250', a function generator 252', and a matching circuit 251', which are designed to drive device 161' at + / -V'. In this case, the additional RF amplifier 250' may be coupled to an AC power supply that can be arranged to power both RF amplifiers 250 and 250'. In one embodiment, the AC power supply 210 may provide the same AC power (AC voltage) to each amplifier. The additional components may have a similar arrangement to the other components of the system, thereby allowing RF amplifier 250' to also be coupled to the function generator 252' and the matching circuit 251', which is also coupled to device 161' across the positive voltage rail +V' and the negative voltage rail -V'. Such an arrangement allows the system to drive multiple piezoelectric devices at different frequencies.

[0120] When utilizing various aspects of the embodiments, it will become apparent to those skilled in the art that combinations or modifications of the above embodiments are possible for acoustic cleavage. Although the embodiments are described in language specific to structural features and / or methodological actions, it should be understood that the appended claims are not necessarily limited to the specific features or actions described. The specific features and actions disclosed should instead be understood as embodiments of the claims useful for illustration.

Claims

1. It is an acoustic system, Piezoelectric devices and AC power supply for supplying alternating current (AC) voltage, An AC-DC converter coupled to the AC power supply, for converting the AC voltage supplied by the AC power supply into a DC voltage, A function generator for generating an input signal at the resonant frequency of the piezoelectric device, The AC-DC converter, the function generator, and the amplifier coupled to the piezoelectric device are provided. An acoustic system in which the amplifier generates an output signal by amplifying the input signal in accordance with the DC voltage, and uses the output signal to drive the piezoelectric device.

2. The acoustic system according to claim 1, further comprising a power factor correction (PFC) circuit coupled to the AC power supply for correcting the power factor of the AC voltage supplied by the AC power supply.

3. The acoustic system according to claim 2, wherein the PFC circuit maintains the power factor at 0.

9.

4. The acoustic system according to claim 1, further comprising a power converter coupled between the AC-DC converter and the amplifier, wherein the power converter converts the DC voltage into a drive voltage for the piezoelectric device.

5. The acoustic system according to claim 4, wherein the drive voltage is a first DC voltage, and the function generator is coupled to the power converter that provides the function generator with a second DC voltage.

6. The sound system according to claim 1, wherein the function generator is coupled to the AC power supply and powered using the AC voltage.

7. The piezoelectric device is a first piezoelectric device, and the acoustic system is A second piezoelectric device coupled to the amplifier, A first switch coupled between the first piezoelectric device and the amplifier, A second switch coupled between the second piezoelectric device and the amplifier, A controller configured to close the first switch or the second switch, thereby enabling the amplifier to drive the first piezoelectric device or the second piezoelectric device, respectively. The acoustic system according to claim 1, further comprising the following:

8. The acoustic system according to claim 7, wherein the input signal is a first input signal, the resonant frequency is a first resonant frequency, the output signal is a first output signal, and in response to the controller causing the second switch to close, the function generator provides the amplifier with a second input signal at the second resonant frequency of the second piezoelectric device, and the amplifier generates a second output signal based on the second input signal for driving the second piezoelectric device.

9. The acoustic system according to claim 1, wherein the piezoelectric device is one of a plurality of piezoelectric devices in the acoustic system, and the function generator is one of a plurality of function generators which are part of a frequency selector circuit coupled to the amplifier, and each function generator is configured to generate a specific input signal for driving a specific piezoelectric device among the plurality of piezoelectric devices at the resonant frequency of the specific piezoelectric device.

10. The acoustic system according to claim 9, further comprising a controller for the frequency selector circuit to output a single input signal generated by one of the plurality of function generators at any given time.

11. The acoustic system according to claim 10, wherein the frequency selector circuit comprises a plurality of switches, each switch coupled between at least one of the plurality of function generators and the amplifier, and the controller causes the frequency selector circuit to output the single input signal by closing the switch coupled between the one function generator and the amplifier and simultaneously opening the remaining switches of the plurality of switches.

12. The acoustic system according to claim 11, wherein the plurality of switches are a first plurality of switches, and the acoustic system further comprises a second plurality of switches, each of which is coupled between the amplifier and a different piezoelectric device among the plurality of piezoelectric devices, and the controller is configured to close one of the second plurality of switches and open the remaining switches among the second plurality of switches based on the one input signal output by the frequency selector circuit.

13. The acoustic system according to claim 12, wherein the first plurality of switches are low-power switches and the second plurality of switches are high-power switches.

14. The acoustic system according to claim 1, wherein the amplifier is a single operational amplifier.

15. It is an acoustic system, A piezoelectric device having a resonant frequency, AC power supply for supplying alternating current (AC) voltage, An AC power supply unit and a radio frequency (RF) amplifier coupled to the piezoelectric device, An acoustic system comprising: a function generator coupled to the RF amplifier, which causes the RF amplifier to generate an output signal based on the AC voltage for driving the piezoelectric device, wherein the output signal has a frequency at the resonant frequency of the piezoelectric device.

16. The acoustic system according to claim 15, further comprising a matching circuit coupled between the RF amplifier and the piezoelectric device for matching the input impedance of the piezoelectric device to the output impedance of the RF amplifier.

17. The acoustic system according to claim 16, wherein the input impedance is 47 ohms to 50 ohms.

18. The aforementioned function generator A frequency sweep is performed within a frequency range that includes the expected resonant frequency of the piezoelectric device. The acoustic system according to claim 15, comprising a sweep generator for determining the resonant frequency of the piezoelectric device within the frequency range based on the frequency sweep.

19. The piezoelectric device is a first piezoelectric device, the RF amplifier is a first RF amplifier, the function generator is a first function generator, the resonant frequency is a first resonant frequency, and the acoustic system is A second piezoelectric device having a second resonant frequency, A second RF amplifier coupled between the AC supply unit and the second piezoelectric device, The acoustic system according to claim 15, further comprising: a second function generator coupled to the RF amplifier, for causing the RF amplifier to generate another output signal based on the AC voltage for driving the second piezoelectric device and at the second resonant frequency.

20. The acoustic system according to claim 19, wherein the first and second function generators simultaneously drive their respective piezoelectric devices.

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