Acoustic device with adjustable penetration depth and optical observation function

Abstract

A sound production system is provided. The sound production system includes a handpiece for adjusting the depth of penetration. In a preferred embodiment, adjustment of the penetration depth is achieved by adjusting between a fixed part of the handpiece and an adjustable part of the handpiece. In a more preferred embodiment, adjustment of the penetration depth is accomplished by a plurality of interchangeable adjustable members, each of which is configured to provide a different penetration depth when coupled to a stationary member. Preferred embodiments also include an optical system that provides imaging of the treatment surface and is adjustable to continue imaging the treatment surface according to variations in penetration depth. In some embodiments, an interface between a fixed member and an adjustable member of the handpiece passes through a chamber containing a liquid acoustic coupling medium.

Description

Technical Field

[0001] The present application relates to an acoustic device and its use in a method and system for treating a human body, in particular treating human skin. Background Art

[0002] Focused ultrasound can be used for non-invasive treatment of internal organs of the human body. The focused acoustic energy is transmitted through the skin surface to the target tissue and absorbed at the target tissue, thereby generating thermal and mechanical interactions with the target organ / tissue.

[0003] In recent years, high-intensity focused ultrasound (HIFU) has become a treatment method for a wide range of diseases. In most cases, the treatment zone is located deep within the human body. The removal of brain tumors, prostate tumors, thyroid tumors or uterine fibroids has been a major area of ​​interest. Therefore, HIFU is usually accompanied by an imaging method to visualize and locate the pathological tissue to be treated. Magnetic resonance imaging (MRI) and ultrasound imaging are by far the most popular modalities for experimental treatments as well as commercial systems. The cost and complexity of HIFU systems and their popularity are largely influenced by the need for complex imaging systems, especially in the case of MRI.

[0004] Recently, new approaches have been proposed to treat human skin using HIFU as a treatment modality in combination with optical imaging. Human skin is typically treated using either cryotherapy or laser therapy. Cryotherapy is by far the cheapest and most widespread treatment. However, cryotherapy does not allow for precise control of treatment depth. Due to the surface temperature distribution, the center of the treatment area is typically overtreated and the periphery is undertreated, which greatly increases the likelihood of poor efficacy and post-treatment scarring. Similarly, lasers typically require good light absorption, which is not the case for many diseases. In addition, treatment depth is largely dependent on local emissivity, which can lead to local overexposure, again resulting in poor efficacy and an increased likelihood of scarring. Since laser therapy essentially exposes an open wound to the external environment, the likelihood of infection is also increased.

[0005] The new approach to treating human skin with HIFU allows for more targeted treatments, with energy being precisely deposited within the dermis or epidermis, resulting in a flatter and more controlled treatment area. In addition, the skin surface remains intact because the treatment point is below the surface of the skin due to the focused nature of the ultrasound. This aids the healing process and reduces the likelihood of infection. The proposed treatment approach can treat a wide range of skin conditions, from cancers (such as basal cell carcinoma, squamous cell carcinoma or Kaposi's sarcoma), precancerous lesions (such as actinic keratosis) to other lesions (such as seborrheic keratosis, sebaceous hyperplasia), and finally to milder conditions (such as vascular malformations, viral warts, acne) and many other conditions in the general category of epidermal and skin tumors.

[0006] Figure 1 The basic physiological structure of human skin 51 is shown. Human skin 51 is composed of an outer epidermis layer 40, which is separated from a deeper dermis layer 41 and an even deeper subcutaneous layer 53 by a basement membrane 52.

[0007] Throughout the dermis 41 and subcutaneous layer 53, lymphatic vessels and vasculature 54 provide transport of nutrients, cells, and various pathogens to the skin 51. Macrophages (a type of white blood cell) help transport dead cells out of the dermis 41. In a process called phagocytosis, macrophages engulf and digest cellular debris, foreign material, microorganisms, cancer cells, and anything else that does not have the type of proteins characteristic of healthy body cells on its surface.

[0008] The basement membrane 52 controls the flow of fluids, molecules, and cells between the dermis 41 and the epidermis 40, and also acts as a reservoir for controlled release during physiological remodeling or repair. Since the epidermis 40 does not contain blood vessels, transport through the basement membrane 52 to the epidermis 40 is limited by diffusion processes, which effectively limits the transport of larger particles, cells, or chemicals (such as pigments) across the barrier. The thickness of the above three outer layers of skin is usually between 0.1 mm and 5.0 mm depending on the location on the body.

[0009] HIFU devices with built-in ultrasound imaging are known in the prior art for cosmetic treatment of the skin (deep dermis and below) operating at frequencies up to 4 MHz–12 MHz. However, ultrasound imaging guidance is less important, as features located on the surface of the skin can provide better guidance for the treatment. It is believed that a very well-defined and small focal zone created by a properly designed transducer is a prerequisite for proper treatment of the skin.

[0010] Figure 3 An example of an ultrasound device 57 is outlined, wherein a focused acoustic source 31 is coupled to a housing 1 and generates a focused ultrasound field with a focus 21 located at an acoustic focus distance 33. A coupling medium 58 is placed between the focused acoustic source 31 within the housing 1 and the surface of the skin 55.

[0011] The origin of each skin disease can be attributed to a skin layer or functional element. For example, basal cell carcinoma originates from the basement membrane, while squamous cell carcinoma originates from the squamous layer of the epidermis40, acne on the other hand originates from the sebaceous glands which are usually located in the dermis. Therefore, it is advantageous to selectively affect only the pathological tissue while sparing other layers or fragments of healthy skin. This can speed up the healing process, reduce the probability of infection and reduce the possibility of scarring. Selectivity in skin treatment can be provided by selecting the point of treatment (POT)56.

[0012] In various embodiments, it is advantageous to selectively treat the skin using focused ultrasound, wherein the acoustic focus 21 coincides with a preselected POT 56. The distance between the skin surface 55 and the acoustic focus 21 is referred to as the penetration depth 17.

[0013] In various embodiments, it is advantageous to manufacture a transducer with an adjustable penetration depth because the same device (handpiece) can be used to target tissue at different penetration depths, thereby broadening the range of applications for a single device.

[0014] This problem has been addressed in the prior art by a variety of mechanisms, such as varying the focal length of the focusing transducer 33 . This can be accomplished both mechanically and electronically. Mechanical techniques include the use of acoustic lenses, reflectors combined with temporal field modulation for defocusing or focusing. Alternatively, electronic focusing can be performed using a ring array arrangement, where the effective focusing distance is preset by the time delay of the drive signal reaching each individual ring. However, the above techniques are costly, resulting in increased weight and size, as they require complex mechanical setups or expensive multi-channel drive electronics. In addition, the varying focus distance affects the shape and size of the focal zone produced by the focusing transducer, as the longer the focus distance, the larger the F number, resulting in a larger volume of the focal zone. A larger focal zone affects the resolution of the treatment, as the treatment is performed deeper into the skin.

[0015] What is needed is an ultrasound device designed in a more cost-effective manner so that the depth of the POT can be adjusted without affecting the size and shape of the focal zone. It would be even more beneficial if the device included an imaging system that could be similarly adjusted to track the location of the POT or a corresponding point on the skin surface. Summary of the invention

[0016] The object of the present application is to provide an improved device and method for treating tissue, especially human skin. The embodiments herein use a unique and novel sound generation system for adjusting the penetration depth. In a preferred embodiment, the adjustment of the penetration depth is achieved by adjusting between a fixed component of the handpiece and an adjustable component of the handpiece. In a more preferred embodiment, the adjustment of the penetration depth is achieved by a plurality of interchangeable adjustable components, each of which is configured to provide a different penetration depth when coupled to the fixed component. The preferred embodiment also includes an optical system that provides imaging of the treatment surface and is capable of adjusting to continue to provide imaging of the treatment surface based on changes in the penetration depth. In some embodiments, the interface / interface between the fixed component and the adjustable component of the handpiece passes through a chamber containing a liquid acoustic coupling medium.

[0017] In some embodiments, a sound generating system is provided. The sound generating system includes a fixed component of a handpiece, wherein the fixed component includes a focused acoustic generating source having a fixed acoustic focal length. The sound generating system includes a plurality of adjustable components for the handpiece, wherein each adjustable component of the plurality of adjustable components is designed to be removably and interchangeably coupled to the fixed component of the handpiece one at a time. In a preferred embodiment, the penetration depth of the handpiece is adjusted by coupling different adjustable components of the plurality of adjustable components to the fixed component. This can be achieved by providing adjustable components having different overall lengths along their longitudinal axis.

[0018] In a preferred embodiment, the fixed component of the handpiece further comprises an optical system that images the treatment surface through / through any of the plurality of adjustable components coupled to the fixed component.

[0019] In an embodiment having an optical system, the optical system may include an objective lens and an imaging plane, wherein a distance between the objective lens and the imaging plane along the longitudinal axis is adjustable. In some embodiments, the distance between the objective lens and the imaging plane along the longitudinal axis is adjusted by mechanically moving the objective lens toward or away from the imaging plane along the longitudinal axis.

[0020] In some embodiments, the optical principal axis of the optical system is coaxial with the acoustic principal axis of the focused sound emitting source. In other embodiments, the optical principal axis of the optical system includes a portion that is not coaxial with the acoustic principal axis.

[0021] In some embodiments having an optical system, the optical system includes an imaging plane and at least one optical member having an adjustable optical focus along a longitudinal axis. In some embodiments having an adjustable optical focus, the adjustment is achieved by a liquid lens. In other embodiments, the adjustable optical focus is achieved by one of the group consisting of electrowetting, using a shape-changing polymer, and acousto-optic tuning.

[0022] In some embodiments, the penetration depth is adjustable between at least 0 mm and 5 mm, and the optical depth of field of the optical system is equal to or greater than 5 mm. The adjustment ranges of the penetration depth and the depth of field may also be within other ranges.

[0023] In some embodiments, an interface between a fixed component of the handpiece and any of the plurality of adjustable components passes through a chamber designed to contain a liquid acoustic coupling medium.

[0024] In some configurations, a sound generating system is provided that includes a fixed component of a handpiece and a plurality of adjustable components of the handpiece, wherein each adjustable component of the plurality of adjustable components is designed to be removably and interchangeably coupled to the fixed component of the handpiece one at a time. An interface between the fixed component of the handpiece and any adjustable component of the plurality of adjustable components passes through a chamber designed to contain a liquid acoustic coupling medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Shown is a cross section of human skin and a point of treatment (POT) located beneath the skin surface.

[0026] Figure 2 The sound field generated by the focused sound source and the basic parameters of the focal area are shown.

[0027] Figure 3 A schematic diagram of an acoustic device is shown, the acoustic device comprising a housing with a focused acoustic source coupled to tissue (eg, skin) via a coupling medium, wherein the acoustic focus is located below the surface of the tissue.

[0028] Figure 4 An acoustic device having a housing including a fixed component and an adjustable component coupled to tissue (e.g., skin) to deposit acoustic energy into a selected region of an internal structure (e.g., a vein) at a fixed acoustic focal length of a focused acoustic source is shown.

[0029] Figure 5 The definition of the optical focal length of a focusing optical lens is shown.

[0030] Figure 6 Shows the image of an object formed through an optically thick lens.

[0031] Figure 7 An image of an object formed by a complex optical system including multiple optical lenses (eg, an objective lens) is shown.

[0032] Figure 8 The definitions of the optical depth of field and the optical depth of focus of an optical imaging system including a plurality of optical lenses (eg, objective lenses) are shown.

[0033] Fig. 9 The main parameters of the image sensor are shown.

[0034] Fig.10 An example of a lens system (dimensions in mm) suitable for imaging the surface of tissue (such as skin) via a transparent acoustic path provided by a focused acoustic source is shown.

[0035] Fig.11 The figure shows the change in field of view caused by refraction when light passes through three layers of transparent materials with different refractive indices.

[0036] Fig.12 The objective lens adjustment due to the presence of an acoustically and optically transparent coupling medium in the optical path is shown.

[0037] Fig.13A One embodiment is shown that includes a focused acoustic source with a transparent optical path and an objective lens that forms an image of the surface of the tissue to be treated (eg, skin).

[0038] Fig. 13B An embodiment is shown which includes a focused acoustic source with a transparent optical path and an objective lens that forms an image of the surface of the tissue to be treated (e.g., skin). Fig.13A shallower in the image plane) requires a change in the position of the optical objective lens, so if an objective lens with a fixed optical focal length is used, the objective lens should be moved towards the image plane.

[0039] Fig.14A One embodiment is shown that includes a focused acoustic source with a transparent optical path and an objective lens that forms an image of the surface of the tissue to be treated (eg, skin).

[0040] Fig. 14B An embodiment is shown which includes a focused acoustic source with a transparent optical path and an objective lens that forms an image of the surface of the tissue to be treated (e.g., skin). If the objective lens is in a fixed position relative to the image plane, then adjusting the penetration depth (ratio Fig.14A shallower in the middle) requires changing the focal length of the optical objective lens.

[0041] Fig.15 An exemplary embodiment is shown which comprises a focused acoustic source with a transparent optical path and an objective lens forming an image of the surface of the tissue to be treated (eg skin). A portion of the principal optical axis of the optical objective lens direction is not coaxial with the principal acoustic axis.

[0042] Fig.16 An exemplary embodiment is shown that includes a focused acoustic source with a transparent optical path and an objective lens that forms an image of the surface of the tissue to be treated (eg, skin).

[0043] Fig.17 The important elements of the focused sound source are shown coupled to a fixed part of the housing.

[0044] Fig.18 An example is shown in which the focused sound source is coupled to a fixed part of the housing and the fixed part of the housing is coupled to an adjustable part of the housing. The direction of the coupling is shown by the arrow.

[0045] Fig.19An example is shown in which the focused sound source is coupled to a fixed part of the housing and the fixed part of the housing is coupled to an adjustable part of the housing. The coupling between the fixed part and the adjustable part of the housing is water-tight using a seal.

[0046] Fig. 20 An exemplary embodiment is shown including a focused sound source having a transparent optical path and coupled to a fixed component of a housing including a seal and a fixed groove and ridge. An adjustable component of the housing has a circular opening and a bubble trap. The adjustable component of the housing is shown before being fixed to the fixed component of the housing.

[0047] Fig.21 An exemplary embodiment is shown, which includes a focused sound source having a transparent optical path and coupled to a fixed part of a housing, the fixed part of the housing including a seal and a fixed groove. The adjustable part of the housing has a circular opening and a bubble trap. The adjustable part of the housing is shown after being fixed to the fixed part of the housing.

[0048] Fig. 22 An exemplary embodiment is shown, which includes: a focused sound source having a transparent optical path and coupled to a fixed part of a housing; and a movable optical objective and an image sensor. The adjustable part of the housing has a circular opening and a bubble trap.

[0049] Fig.23 An exemplary embodiment is shown, which includes: a focused sound source having a transparent optical path and coupled to a fixed part of a housing; a movable optical objective and an image sensor in a threaded holder. The adjustable part of the housing has a circular opening and a bubble trap. The adjustable part of the housing is coupled to the fixed part of the housing using a threaded coupling, thereby enabling continuous adjustment of the penetration depth.

[0050] Fig.24 An embodiment is shown, comprising: a focused sound source having a transparent optical path and coupled to a fixed part of a housing; a movable optical objective lens and an image sensor in a threaded holder. The threaded objective lens is magnetically coupled to an outer ring to allow optical focus adjustment. The adjustable part of the housing has a circular opening and a bubble trap. The adjustable part of the housing is coupled to the fixed part of the housing using a threaded coupling, thereby enabling continuous adjustment of the penetration depth.

[0051] Fig.25 is a table showing different parameters of the acoustic focusing area resulting from different configurations of the focused sound source.

[0052] Fig.26is a table showing different configurations of the image sensor and the distance to the object and image resulting in different fields of view, total optical track lengths, and magnifications.

[0053] Fig. 27 is a table showing different combinations of optical resolution, numerical aperture, optical depth of field and optical F-number resulting from different configurations of imaging media and optical objectives.

[0054] Fig.28 Depicted is an example of displaying a real-time image of the skin surface with an augmented reality overlay showing the outline of the lesion to be treated as well as the treatment point.

[0055] Fig.29 An example is shown showing a real-time image of the skin surface with an augmented reality overlay showing blood vessel outlines created using ultrasound imaging data fusion technology.

[0056] Fig.30 Depicted is a block diagram of a treatment system comprising a main unit and a handpiece connected by a wired connection.

[0057] Fig.31 A block diagram of a treatment system is shown, the treatment system comprising a main unit and a separate handpiece connected by a wireless connection.

[0058] Fig.32 A block diagram of a stand-alone handpiece of a handheld therapeutic system is depicted.

[0059] Fig.33 The principle of continuous adjustment of the penetration depth is shown.

[0060] Fig.34 An example of a configuration for electrically adjusting the penetration depth is shown.

[0061] Fig.35 The structure of the handpiece is shown. DETAILED DESCRIPTION

[0062] Several embodiments disclosed in this application combine focused acoustic energy and optical imaging. From a physics perspective, both acoustics and optics involve wave phenomena governed by diffraction, reflection, and refraction, and therefore, they share many terms used to describe the various elements and effects. Throughout this document, elements, phenomena, parameters, etc. related to acoustics are accompanied by the adjective "acoustic / acoustic". Similarly, elements, phenomena, parameters, etc. related to optics are accompanied by the adjective "optical / optical" to avoid possible misunderstandings. Furthermore, throughout this document, the term "acoustic / acoustic" is understood to relate to mechanical waves with frequencies ranging from 1 Hz to 1 GHz, while "optical / optical" is understood to relate to wavelengths ranging from 10 -10 m to 10 -3 m's electromagnetic waves.

[0063] A sound field focused on the sound source

[0064] In several embodiments disclosed herein, a focused acoustic source 31 is used to generate a focal point 21 of high acoustic intensity within the tissue 51 to be treated / treated, such as Figure 1 and Figure 3 In a preferred configuration, the acoustic focus 21 is located at an acoustic focal length 33 on the acoustic principal axis 22 . Figure 2 The profile of the focused acoustic field 36 produced by the focused acoustic source 31 is shown. The resulting focused acoustic field 36 produces an acoustic focus zone, which is the volume around the focus 21, defined by a 6 dB pressure drop (reduction) compared to the maximum pressure at the acoustic focus 21. The dimensions of the acoustic focus zone include an acoustic focus depth 34 and an acoustic focus diameter 35. As shown in Equations 1 and 2, the acoustic focus depth DOF a 34 and acoustic focusing diameter FD a The relationship between the characteristics of 35 and the focused sound source 31 is given by the operating frequency f0, the aperture a=D / 2 and the acoustic focal length (33) F a Given as , where D is the diameter 32 of the focused sound source.

[0065]

[0066] Acoustic wavelength λ0=c a / f0, where c a is the speed of sound in a given medium. In some embodiments, the medium is water and c a =1480m / s. Acoustic F number F # a =F a / D.

[0067] In preferred embodiments, the size of the acoustic focal zone should be matched to the intended treatment regimen, particularly the size of the organ or tissue to be treated. In some embodiments, the focused acoustic field is used to treat a selected layer of human skin, known to be between 1–5 mm thick. In this case, the acoustic focusing depth 34 can be achieved by appropriately selecting the operating frequency f0. The operating frequency f0 can range from 0.1 MHz to 1 GHz, or from 1 MHz to 100 MHz, or various other ranges depending on the embodiment. The acoustic F number defines the strength of the focus. The lower the acoustic F number, the stronger the focus. The F of some embodiments may be greater than the F number of the acoustic focal zone. # a can range from 0.5 to 100. A more preferred embodiment may exhibit F # a From 0.51 to 20, or from 0.55 to 10. Those skilled in the art will appreciate that strong focusing is given by Formula 3:

[0068]

[0069] where F C # is the critical value of the acoustic F number. In some preferred embodiments, it is desired to produce strong focusing, that is, F # a <F C # . Fig.25 Possible combinations of operating frequencies and acoustic F-numbers that may be used in the various embodiments described herein are shown. Fig.25 The values ​​in are based on focused ultrasound propagation in water and soft tissue, assuming that the speed of sound c a = 1500 m / s. Those skilled in the art will appreciate that the speed of sound in soft tissue is slightly higher than the speed of sound in water, however this difference will not affect the overall range of parameters of the preferred embodiment. Fig.25 Several preferred configurations of focused sound sources are outlined.

[0070] Acoustic devices using focused sound sources

[0071] Figure 3 A schematic diagram of an acoustic device is shown, the acoustic device comprising a shell with a focused sound source 31, the focused sound source is coupled to a tissue (e.g., skin) through a coupling medium, and the acoustic focus is located below the surface of the tissue. The acoustic device comprises a focused sound source 31 coupled to the shell 1. In a preferred configuration, the focus 21 generated by the focused sound source 31 along the acoustic principal axis 22 is located below the reference plane 20. Therefore, when the reference surface 20 is coupled to the surface 55 of the tissue to be treated, the focus is located within the organ or tissue to be treated. In some embodiments, the tissue or organ to be treated is human skin including an epidermis 40 and a dermis 41.

[0072] In some embodiments, the acoustic focus 21 is located below the reference surface 20. Those skilled in the art will appreciate that this can be achieved by configuring the acoustic focal length 33 to be greater than the effective distance 44 between the vertex of the focused sound source and the reference plane 20. The difference between the focal length and the distance 44 is equal to the penetration depth 17.

[0073] In a preferred embodiment, the space between the focused sound source and the reference plane 20 within the housing 1 is filled with an acoustically transparent (i.e., having low acoustic attenuation) substance, the acoustic coupling medium 58. In some embodiments, this can be a fluid, liquid or gas. In another embodiment, the acoustic coupling medium is water.

[0074] Acoustic device with focused sound source and adjustable penetration depth

[0075] Figure 4The use of a device with an adjustable penetration depth 17 in three different configurations to treat internal structures 163 located at different depths below the surface 55 of the tissue being treated (e.g., skin) is shown. Figure 4 In the illustrated embodiment, the housing 1 includes more than one member that is adjustable relative to each other along the longitudinal axis 22. However, in other embodiments, the housing 1 may include more than two members that are adjustable relative to each other along the longitudinal axis 22. Figure 4 In the embodiment shown, the housing 1 comprises two components: one coupled to the focused sound source 31, referred to as a fixed part 159 of the housing, and the other an adjustable part 161 of the housing.

[0076] In such Figure 4 In the illustrated embodiment, the distance between the vertex of the focused sound source 31 and the reference plane 20 is equal to the length of the fixed portion 160 and the length of the adjustable portion 162 along the longitudinal axis 22. The sum of the length of the fixed portion 160 and the length of the adjustable portion 162 of the housing plus the penetration depth 17 equals the acoustic focal length 33.

[0077] In some embodiments, the penetration depth is adjustable by providing the housing 1 with a plurality of replaceable adjustable components 161. In such embodiments, each adjustable component 161 in the plurality of replaceable adjustable components has a different length 162 measured along the longitudinal axis 22. In some embodiments, the adjustable length 162 of different adjustable components 161 in the plurality of adjustable components is given in steps of 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 1 mm, 2 mm, 3 mm, or any distance between 0.01 mm and 1000 mm. In some embodiments, it is advantageous to match the adjustment step size with the acoustic focus depth of the focused sound source 31, as given by formula (1). In this case, the adjustment step size is equal to a fraction of the acoustic focus depth 34. In some other embodiments, the adjustment step size is a multiple of the acoustic focus depth 34, ranging from 0.001 to 1000.

[0078] In some other embodiments, the housing 1 includes more than two parts, more than three parts, or more than four parts. These parts can move along the acoustic axis 22 that defines the length of the adjustable part 162. In addition to moving along the acoustic axis 22, these parts can also rotate or move in any other direction to continuously adjust the length of the adjustable part 162 in the range from 0mm to 1000mm. In other embodiments, the adjustment range is 0mm to 100mm or 0.01mm to 20mm. In a preferred embodiment, the adjustment range is 1mm to 10mm.

[0079] In some embodiments, there may be a coarse adjustment mechanism and a fine adjustment mechanism. As just one non-limiting example, a three-piece housing may have two adjustable components 162. One of the adjustable components may be threaded to allow coarse adjustments, such as 1 mm adjustments, relative to a fixed component, while the second adjustable component may allow fine adjustments, such as 0.1 mm adjustments, relative to a fixed component of the housing.

[0080] Optical imaging using an optical device

[0081] The preferred embodiment comprises optical means which enable continuous and real-time observation of the surface 55 of the tissue to be treated (eg skin). Figure 5 A feature illustrating the basic properties of a biconvex optical lens is the optical focus distance 104, which is the distance between a principal point 156 located on the optical principal axis 130 and an optical focal point 105. By definition, the optical focal point 105 is where parallel incident light rays 154 meet as a focused beam 155 after passing through the lens.

[0082] Most of the embodiments disclosed herein utilize more complex optical systems, including "thick" optical lens arrangements, such as Figure 6 As shown. The thick optical lens is lens z l The size of lens 158 is defined by the distance between the primary principal point 110 and the secondary principal point 111 . Figure 6 An optical biconvex lens 129 is depicted, which is aligned with the distance z o The object 100 at (102) forms an image 108 at a distance zi(113) from the secondary principal point 111. The distance between the object 100 and the image 108 is called the total optical track length z t (106), given by Formula 4:

[0083] z o +z l +z i =z t (4)

[0084] Those skilled in the art will understand that Figure 6 The system shown does not always form a real image. However, if the optical focal length F o If a given lens characterized by (104) satisfies the correct conditions, then the following formula (5) holds:

[0085]

[0086] The above formula relates the three main parameters of the optical system and provides two degrees of freedom.

[0087] Several embodiments disclosed herein include complex imaging systems that include compound lenses. A compound lens is a collection of simple lenses of different shapes, made of materials with different refractive indices, arranged in series along a common axis. Fig.10 An example of a preferred configuration of a composite lens is shown.

[0088] Figure 7 An optical system is shown in which a compound lens is shown as an optical objective 115 which forms an image 108 having a characteristic size 109. The object 100 has a characteristic size d o (101) and assumes that it is the size of the largest object that can be imaged in a given configuration. In this case, the feature size d o (101) defines the field of view (FOV). o (102) and the image is at distance z i (113) is formed.

[0089] An optical objective is characterized by its optical focal length F o (104). As is known to those skilled in the art, optical objective manufacturers use several different characteristics to describe the objective. In addition to the optical focal length 104, the optical back focal length 107 may be specified as the distance between the last optical element of the objective and the image. Furthermore, some manufacturers use the term "focal length" to denote the back optical focal length, which may lead to ambiguity. As used herein, the term "optical focal length" 104 is to be understood in its classical form, e.g. Figure 5 The distance between the object and the front element of the objective is called the working distance 102 (see Figure 6 ).

[0090] Formula (5) is also applicable to compound lenses, such as the optical objective lens 115. In addition, the field of view angle AFOV(103) is defined as:

[0091]

[0092] or equivalently

[0093]

[0094] This means

[0095]

[0096] Therefore, the magnification MAG is given by the following formula:

[0097]

[0098] Formulas (4), (5) and (8) can be combined to determine the object size d o(FOV) and its value for a given image sensor and optical objective lens at a given image size d i and optical focal length F o The next position.

[0099] In several embodiments, both object 100 and image 108 are rectangular and are characterized by height, width, and diagonal. The characteristic dimensions of the object and image (101 and 109, respectively) can be width, height, or diagonal, so a vertical FOV (V), a horizontal FOV (H), and a diagonal FOV (D) can be defined. Fig.26 Several preferred configurations of the embodiments disclosed herein are shown.

[0100] Fig. 9 The main parameters of the image sensor are shown. It will be appreciated by those skilled in the art that, in reality, the image is formed on the surface of the image sensor. Therefore, the image plane can be considered as the surface of the image sensor, and the parameters of the image (such as height 123, width 126 and diameter 128) can be directly converted into parameters of the image sensor 25. In addition, in several embodiments, the size of the image is determined by the size of the image sensor. In some embodiments, the image sensor can be a CCD (charge coupled device) camera, in some other embodiments, it is an active pixel sensor CMOS or any other image sensing device.

[0101] The image sensor device has an optical format such as a typical 4:3 or 16:9. Several embodiments disclosed herein utilize image sensors of optical formats 1 / 1", 1 / 2", 1 / 2.3", 1 / 2.5", 1 / 2.7", 1 / 2.9", 1 / 3", 1 / 4", 1 / 10", or any other optical format.

[0102] Fig.26 Examples of embodiment configurations are given, including image sensor optical format, object size and its position for a given optical objective.

[0103] Some embodiments disclosed herein use Figure 8 The optical system shown. For a given configuration of an objective, there are certain limitations in imaging capabilities, specifically resolution, optical depth of field 120, and optical depth of focus 123. The optical depth of field is the range along the principal optical axis 130 within which an object remains sharp. The optical depth of focus is the distance along the principal optical axis 130 within which an image remains sharp.

[0104] Diffraction is Figure 8The limiting factor in the imaging capability of the optical system shown. Diffraction limits the resolution, which is defined as the minimum distance between two different points on an object that can still be resolved in the image. Resolution is inherently related to the numerical aperture NA, the wavelength of the light, and the medium through which the light travels. The numerical aperture is defined in Equation 10 as follows:

[0105] NA=n sinα (10)

[0106] Where n is the refractive index of the medium and α is the aperture half angle 119, such as Figure 8 shown.

[0107] The resolution is then determined by the Rayleigh criterion, which is given by:

[0108]

[0109] And the optical depth of field:

[0110]

[0111] where λ is the wavelength of light.

[0112] In some embodiments, the resolution of the optical system in the device ranges from 100 nm to 1000 μm. In some embodiments, the resolution ranges from 0.1 μm to 100 μm. In more preferred embodiments, the resolution ranges from 0.5 μm to 50 μm.

[0113] As part of the optical system or as a supplement to the optical system, embodiments can use light to illuminate the surface to be observed. Several embodiments disclosed herein use light with a wavelength range of from 420nm to 900nm. Other embodiments use light with a wavelength range of from 100nm to 20000nm. In a preferred embodiment to illuminate the observation area, the light wavelength ranges from 420nm to 890nm.

[0114] An optical system is also characterized by the optical F number, which describes the amount of light that passes through the objective lens. The optical F number is defined in Equation 13 as follows:

[0115]

[0116] Among them, D o yes Figure 8 The optical aperture 118 is shown. In some embodiments, the optical F number ranges from 1 to 50. In some other embodiments, the optical F number ranges from 1 to 20. In a preferred embodiment, the optical F number ranges from 1 to 5.

[0117] Fig. 27 Several configurations of the preferred embodiment are shown, outlining the resolution, field of view, and optical depth of field.

[0118] Imaging through a medium with variable refractive index

[0119] In some embodiments disclosed herein, an image is formed by light passing through one or more media having a given refractive index. In some embodiments, light propagates through air. In some other embodiments, light propagates through water and air. In still some other embodiments, light propagates through water, glass, and air. In some embodiments, light propagates through one or more media, which can be any sequential combination of air, water, liquid, fluid, gas, plastic, polymer, and any optically transparent material for a given light wavelength range. The optically transparent material can be, for example, polycarbonate, polymethyl methacrylate, acrylic, glass, or any other optically transparent material.

[0120] Fig.11 A light ray 164 emitted from an object 100 is shown, which passes through a medium 3136 with a refractive index of n = n3 at an angle 133. Then, the light ray refracts at the interface between medium 3 and medium 2 and propagates through a medium 2 138 with a refractive index of n = n2 at an angle 132. Then, the light ray refracts again at the interface between medium 2 and a medium 1 with a refractive index of n = n1. Finally, the light ray reaches the objective lens at an angle 132. Given that n1 < n3 < n2, the effective field of view angle decreases because angle 137 is less than the field of view angle of the objective lens 132. This also results in the FOV 140 being less than the FOV of a system where the media 2 and 3 are the same as medium 1.

[0121] Some embodiments show an optical system configured as Fig.11 shown. Medium 3 is water with n = 1.33 and a thickness of 139. The thickness of medium 3 can be any thickness, but in this embodiment, the thickness 139 is 12 mm. Medium 2 is polycarbonate with n = 1.53. Similarly, medium 2 can have any thickness, but in this embodiment, the thickness of medium 2 is 5 mm. Medium 1 is air with n = 1. Medium 1 can also have any thickness, but in this embodiment, the thickness of medium 1 is 17 mm. The field of view angle of the objective lens is 26.5°. After refraction at the interfaces between media 1, 2, and 3, the resulting field of view angle is reduced to 20.0°, and the FOV is 13.76 mm, while it is 16.07 mm when the medium is only air.

[0122] In several embodiments disclosed herein, due to the reduction of the FOV caused by light passing through media with different refractive indices, the image appears "closer" to the objective lens. Therefore, it is necessary to move the objective lens closer to the object by a distance 142 to produce a clear image, as Fig.12 shown. The adjustment range is from 1 μm to 1500 μm. In a more preferred configuration, the adjustment range is from 5 μm to 500 μm.

[0123] Acoustic device with adjustable penetration depth and optical imaging at constant optical focal length

[0124] Fig.13A and Fig. 13B An example of an embodiment comprising a focused acoustic source with a transparent optical path and an objective lens forming an image of the surface of tissue to be treated (eg, skin) is shown. Fig.13A The embodiment shown in comprises a focused sound source 31 coupled to a fixed part 159 of the housing. The focused sound source 31 has a hole. Fig.13A The embodiment shown in the figure also includes an optical objective 115, which forms an image 108 of the object 100. The fixed part of the housing together with the adjustable part 161 of the housing form a housing that can contain the acoustically and optically transparent coupling medium 58. The adjustable part 161 of the housing includes one or more components and is configured to adjust the distance between the acoustic focus 21 and the reference plane 20.

[0125] In some embodiments, the optical axis 130 is coaxial with the acoustic axis 22. The optical system may include one or more lenses of various shapes and sizes, such as convex-convex lenses, plano-convex lenses, convex-concave lenses, concave-concave lenses. The focused acoustic source 31 with a hole allows light to pass through the interior of the housing, making it possible to continuously and in real time observe the object 100. It is understood that the object 100 is preferably a treatment surface. In several embodiments disclosed herein, the object 100 may be, but is not limited to, a skin surface, a tissue surface, a skin surface with a tumor, and many other surfaces. In several embodiments, the adjustable part 161 of the housing has an opening 165 that allows light and sound waves to pass through. The opening is covered with an optically transparent and acoustically transparent material, referred to as an acoustic-optical window 168. In some embodiments, the material may be a thin plastic foil, such as, but not limited to, low-density polyethylene. The hole in the focused acoustic source is filled by an optical separator 4. The optical separator 4 acts as a plug made of an optically transparent material to block the hole in the acoustic radiator, so it prevents the coupling medium 58 from leaving the impermeable chamber 166, but provides an optically transparent path for observation. In some embodiments, the optical separator can be bonded directly to the sound source 31. In some other embodiments, it is bonded to a specific element of the fixed part 159 of the housing. The optical separator can be made of polycarbonate, plexiglass, transparent plastic, glass or other transparent materials.

[0126] In some embodiments, the fixed part 159 of the housing, the adjustable part 161 of the housing, the focused sound source 31, the optical separator 4 and the photoacoustic window 168 are configured to form a watertight chamber or an impermeable chamber 166, such as Fig.21 shown.

[0127] In some embodiments, the optical objective 115 is configured with the watertight chamber 166 to allow imaging of an object in an opening of an adjustable component coupled to the housing. The primary principal point of the objective 110 is at a distance 102 from the reference plane 20 (also the object plane). The image is at a distance 113 from the secondary principal point of the objective 111.

[0128] In some embodiments disclosed herein, the acoustic device is configured to allow adjustment of the penetration depth. In some embodiments, changes in the penetration depth also change the total optical track length 106 to cause the image 108 to be out of focus. In some embodiments, the image can be refocused by adjusting the distance 113 along the longitudinal axis between the objective lens 115 and the imaging plane 117 while the optical focal length of the objective lens remains constant.

[0129] Given the following set of formulas:

[0130]

[0131] Where z is the total length of the optical track, z l is the objective lens length, z i and z o are the distances to the image and the object respectively, F o is the optical focal length. After z changes due to the penetration depth adjustment, the new z can be estimated using the following formula i * , thus obtaining the new total length of the optical track z * :

[0132]

[0133] Back to Fig.13A and Fig. 13B , Fig.13A The optical focal length F of the embodiment shown o 9mm, z l =7mm. The acoustic focal length is 15mm, the diameter of the focused sound source is 20mm, and the operating frequency of the focused sound source is 12MHz. This embodiment is configured to produce a penetration depth of 3mm. Result z i =11.88mm, z o =37.12mm, and the total optical track length is 56mm.

[0134] The same embodiment is reconfigured to produce a penetration depth of 1 mm, as Fig. 13B This is achieved by adding 2 mm of distance to the adjustable part 161 of the housing or moving the adjustable part of the housing 2 mm away from the focus source 31. After reconfiguration, the total optical track length is 58 mm, resulting in z i =11.67mm, z o=39.33mm. Therefore, the objective lens moves 0.21mm toward the image plane to make the image clear again.

[0135] Acoustic device with adjustable penetration depth and optical imaging with variable optical focal length

[0136] In some different embodiments, the adjustable optical focus is provided by one or more lenses with adjustable optical focus. In this case, refocusing the image after adjusting the penetration depth 17 does not require mechanical movement of the objective lens, thereby keeping the distance of the image to the secondary principal point of the objective lens 113 constant for all ranges of penetration depth. In many cases, it is advantageous due to simplicity, low cost and compactness. In some embodiments, one or more lenses in the objective lens have the possibility to change its optical focal length. In some embodiments, this is achieved by using a liquid lens, which can change its shape and therefore its radius of curvature, resulting in a change in the optical focal length. In some embodiments, the adjustable optical focus lens is electrowetting, using shape changing polymers and acousto-optic tuning, where the optical focus is controlled by an electrical signal.

[0137] As an example, Fig.14A The configuration embodiment shown has an optical focal length F o is 9.00 mm, and z l =7 mm. The objective lens includes at least one adjustable optical focal length lens using electrowetting. The acoustic focal length is 15 mm, the diameter of the focused acoustic source is 20 mm, and the operating frequency of the focused acoustic source is 12 MHz. For example, the embodiment is configured by using appropriate adjustable components of the housing to produce a penetration depth of 3 mm. Result i =11.88mm, z o =37.12mm, the total optical track length is 56mm.

[0138] The same embodiment can be reconfigured to produce a penetration depth of 1 mm, for example by adding a 2 mm distance to the adjustable portion of the housing ( Fig. 14B ). The total optical track length is now 58mm (56mm + 2mm), and the distance from the image to the secondary principal point remains unchanged. i =11.88mm, and z o =39.12 mm. The objective lens remains in the same original position; however, its optical focal length is adjusted to be equal to F o =9.11mm in order to refocus the image after reconfiguration.

[0139] Acoustic device for fixed optical imaging system with adjustable penetration depth and extended optical depth of field

[0140] Some other embodiments disclosed herein include a focused acoustic source 31 coupled to a fixed component 159 of a housing. The focused acoustic source 31 has an aperture. The embodiment also includes an optical objective 115 that forms an image 108 of the object 100. The fixed component of the housing together with the adjustable component 161 of the housing form a housing that can contain an acoustically and optically transparent coupling medium 58. The adjustable component 161 of the housing includes one or more components and is configured to adjust the distance between the acoustic focus 21 and the reference plane 20. In these embodiments, the optical imaging system is configured to produce a clear or acceptably clear image at all achievable penetration depths of the system, i.e., even after the penetration depth is changed. This can be achieved by using an objective with an extended (relatively large) optical depth of field 120. In some embodiments, the optical depth of field 120 matches (is equal to or greater than) the achievable penetration depth range. In some embodiments, the optical depth of field is 0 mm to 5 mm or 0.1 mm to 5 mm. In some other embodiments, the optical depth of field is 1 mm to 100 mm. In a preferred embodiment, the optical depth of field is 1 mm to 10 mm.

[0141] Acoustic device with adjustable penetration depth and non-coaxial arrangement for optical imaging

[0142] Fig.15 An example of an embodiment comprising a focused acoustic source having a transparent optical path and an objective lens for forming an image of a tissue surface to be treated (e.g., skin) is shown, wherein a portion of an optical principal axis in the direction of the optical objective lens is not coaxial with the acoustic principal axis. Such a configuration is advantageous because it allows for more flexible arrangement of the acoustic and optical devices. In some embodiments, light propagating along an optical principal axis 130 coaxial with the acoustic principal axis 22 is reflected by an optical reflection device 150 (e.g., a mirror across the separator 4) and directed at a reflection angle 151 into an optical system, including but not limited to a lens system or an objective lens 115. In some embodiments, the optical axis is reflected or refracted more than once using (but not limited to) a combination of optical devices such as mirrors, prisms, beam splitters, etc. In addition, the transparent path can be split into more than one path and then directed into different optical systems for further processing using (but not limited to) image sensors, eyepieces, etc. In such an embodiment, one or more image planes 117 are not parallel to the object plane 116.

[0143] The preferred embodiment disclosed herein includes an optical device that enables continuous and real-time observation of the surface of the tissue to be treated (e.g., skin). The acoustic field 36 generated by the focused acoustic source 31 and the light field 38 provided by the objective lens 115 are combined together, such as Fig.16 shown.

[0144] Bubble Trap

[0145] Fig.17An isometric view of a focused sound source 31 coupled to a fixed component of the housing 1 is shown. Figure 5 The embodiment shown in includes a focused sound source 31 coupled to a housing 1, which includes a bubble trap 5. In some embodiments, a gas (e.g., air) dissolved in a coupling medium 58 (e.g., water) forms bubbles that can prevent a clear view of an object, such as a skin surface. In addition, the bubbles may block sound waves propagating from the focused sound source to the tissue. Therefore, it is proposed herein to design a bubble trap 5 in an internal cavity that houses the coupling medium 58 to reduce or eliminate bubbles during operation. In some embodiments, the bubble trap is a groove or channel arranged around the circumference of the focused sound source 31, so that the chamber formed by the groove is located above a line defined by the focused sound source 31. In some embodiments, the bubble trap is circular (see Fig.17 ), but in other embodiments, the bubble trap is square, rectangular, and any other shape.

[0146] The distance between the bottom of the bubble trap and its top is referred to as the depth of the bubble trap 167. In some embodiments, the depth of the bubble trap is from 0.1 mm to 100 mm. In some other embodiments, the depth of the bubble trap 167 is from 0.5 mm to 20 mm. In a more preferred embodiment, the depth of the bubble trap 167 ranges from 1 to 10 mm. Some embodiments feature the bubble trap 5 being coated with a coating that attracts and retains bubbles, such as a bubble capture surface, a nanoparticle-based coating, and the like. Non-limiting examples of such coatings include polyparaxylene coatings, polyamide coatings, and the like.

[0147] During operation, bubbles tend to collect around the apex of the concave surface of the focusing piezoelectric member 31, where the optical separator 4 is located. The collection of bubbles around the apex of the concave surface of the focusing piezoelectric element 31 can amplify undesirable effects because the transducer / handpiece is typically operated face-down. The bubble trap 5 is in the form of a groove or channel or container around the sound source to allow bubbles to be transferred from undesirable locations to the bubble trap 5 by the simple operation of inverting the handpiece / transducer and then slowly returning it to the desired position (face-down), optionally with gentle shaking, at which point the bubbles are captured in the bubble trap 5. The bubbles are retained in the trap by gravity.

[0148] The bubble trap may be a continuous channel surrounding the entire piezoelectric member 31. However, in other embodiments, the bubble trap may include more than one channel, for example Fig.17 The example shown in Fig.17 In the embodiment, two channels are used around the piezoelectric member 31. In other embodiments, more than two channels may be used.

[0149] Acoustic device with incrementally adjustable penetration depth

[0150] like Fig.18 and Fig. 20 As shown, and previously Figure 4 As shown, in some embodiments disclosed herein, the penetration depth adjustment is performed in steps, and the step length is predefined by the length of the adjustable part 162. A fixed housing element 159 is combined with several adjustable housing elements 161 to define a range of penetration depths. The adjustment is performed in the following steps: releasing the fixing ring 170, removing the acoustic-optical window 168, removing the coupling medium 58 through the refilling port, replacing the adjustable part 161 of the housing with the adjustable part 161 of a new housing with the desired penetration depth, refilling the coupling medium 58 through the refilling port, covering the opening 8 with the acoustic-optical window 186, and reattaching the acoustic-optical window to the housing using the fixing ring 170 and the fixing groove 12.

[0151] In several embodiments disclosed herein, opening 8 is used as a refill port. In some other embodiments, a single and / or multiple refill ports may be provided.

[0152] In some embodiments, the adjustable range is from 0.1 mm to 1000 mm. In some other embodiments, the adjustable range is from 0.2 mm to 100 mm. In a more preferred embodiment, the adjustable range is from 0.2 mm to 10 mm. The step size of the range can vary and can be in steps of 0.1 mm to 100 mm. In some other embodiments, the adjustment step size is matched to the acoustic focus depth, so it is a fraction or multiple of the acoustic focus depth, ranging from 0.01 to 50.

[0153] In some embodiments, the adjustable housing element 161 is attached to the fixed housing element 159 using a tight fit (snap, clip) with grooves 9 and ridges 10 . Fig.18 This configuration is shown, with the attachment direction 14 also indicated.

[0154] In many embodiments, the coupling between the fixed component and the adjustable component of the housing is achieved by, but not limited to, snap-fit, thread, tight fit, press fit, etc.

[0155] Fig.19 A cross section of an example of a focused sound source coupled to a fixed component of a housing coupled to an adjustable component of the housing is shown. The coupling between the fixed component and the adjustable component of the housing is water-tight using seal 6. Some embodiments disclosed herein include a water-tight coupling between a fixed housing element 159 and an adjustable housing element 161. In many embodiments, water-tightness is provided by a solid or liquid sealant. Fig.19As shown, in some embodiments, water tightness is provided by one or more seals 6. The seals can also be O-rings or other types of seals with various cross-sections. The seals can be made of silicone, plastic, polymer, rubber or various other materials.

[0156] In a preferred embodiment, the adjustable part 161 of the housing includes an opening 8 that provides a clear path for sound waves toward the acoustic focus 21. In some embodiments, the opening is circular and has a diameter 19 in the range of 0.1 mm to 100 mm. In other embodiments, the circular opening is in the range of 1 mm to 30 mm. In some other embodiments, the opening can be square or rectangular, or any other shape.

[0157] In the preferred embodiment disclosed herein, an electrical matching circuit 2 is provided to assist the energy flow between the RF power amplifier 308 and the associated output filtering and matching 309 and the focused acoustic source 31. In a preferred configuration, the electrical matching circuit provides a true and predefined impedance at a selected frequency or frequency range. In a more preferred configuration, the impedance is matched to 1 to 1000 Ohms at one or more frequencies between 1kHz and 1000MHz, and more preferably, to 50 Ohms in the frequency range of 1MHz to 100MHz. In some embodiments, the matching circuit is placed on a single or multi-pole printed circuit board having one or more openings that provide a clear optical path along the optical axis 130. The diameter of the openings in the matching circuit 18 ranges from 1 to 100mm.

[0158] Acoustic device with optical observation function and incrementally adjustable penetration depth

[0159] As mentioned above about Figure 4 and Fig.18 The discussion and now about Fig. 20 As discussed, in several embodiments disclosed herein, the penetration depth adjustment is performed in steps, the step length being predefined by the length of the adjustable member 162. The focused sound source is coupled to the fixed housing element 159 and combined with one of the plurality of adjustable housing elements 161 to define a range of penetration depths. The penetration depth can be changed by simply replacing the adjustable housing element 161 from the current element to one of the other adjustable housing elements in the plurality of adjustable housing elements.

[0160] like Fig.21 As shown, the fixed housing part 159 together with the adjustable housing part 161 , the focused sound source 31 , the optical separator 4 and the photoacoustic window 168 form a watertight chamber 166 for accommodating the coupling medium 58 .

[0161] Fig. 22An isometric three-dimensional cross-sectional view of an acoustic device with adjustable penetration depth and optical observation capabilities is shown. Fig. 22 As shown, the focused sound source 31 can be made with a hole, whether it is constructed as a single focused piezoelectric element, a multi-element structure, or a planar element with attached elements for focusing the acoustic signal. In a preferred embodiment, the hole is located at the center of the focused sound source 31 along the acoustic principal axis 22. It is understood that in Fig. 22 In the embodiment shown, the acoustic axis 22 is also the longitudinal axis of the device. The aperture allows for mechanical stress relief during high power operation of the focused acoustic source 31. Furthermore, the aperture can be used to allow optical access to an imaging system through the optical separator 4 where it is mounted.

[0162] In a preferred embodiment, a fixed portion 159 of the housing is coupled to the focused sound source 31 and is used in conjunction with an adjustable portion 161 of the housing of varying lengths 162 so that the penetration depth 17 can be incrementally adjusted. In some embodiments, the increments range from 0.1 mm to 100 mm, and in some other embodiments, the increments range from 0.2 to 5 mm. In addition, the fixed portion of the housing is coupled to a handpiece housing 30, which includes a camera housing 26, which contains an image sensor 25 and a movable objective lens 115. The camera holder 26 allows the objective lens to move toward and away from the image sensor. It will be appreciated by those skilled in the art that the image sensor 25 is positioned so that its sensing surface coincides with the image plane 117 of the imaging system, as described above. In addition, the object being observed is the surface of the tissue to be treated, such as the surface of the skin. Once the reference plane of the housing 20 is coupled to the surface of the tissue to be treated, the surface can be observed.

[0163] Many embodiments disclosed herein adjust the penetration depth 17 by providing a plurality of adjustable components 161 of the housing. It will be appreciated by those skilled in the art that each change in the penetration depth changes the distance of the reference plane 20, which is identical to the object plane 116 in the preferred configuration, to the image plane 117, which is the sensing surface of the image sensor 25 in the preferred configuration. In some embodiments, this means that the objective lens needs to be moved along the optical axis 130 to refocus the image. Equations (4) to (8) can be used to estimate the necessary displacement.

[0164] In some other embodiments, the optical system can be designed to have an optical depth of field that covers the required range of penetration depths. In some embodiments, the optical depth of field is 100 mm, and in some other embodiments, the optical depth of field is 5 mm.

[0165] Acoustic device with optical observation function and continuously adjustable penetration depth

[0166] Fig.23A cross-sectional view of an acoustic device with continuously adjustable penetration depth and optical observation capabilities is shown. Fig.23 As shown, the focused sound source 31 can be made with a hole, whether it is constructed as a single focused piezoelectric element, a multi-element structure, or a planar element with attached elements for focusing the acoustic signal. In a preferred embodiment, the hole is located at the center of the focused sound source 31 along the acoustic principal axis 22. It is understood that in Fig.23 In the embodiment shown, the acoustic axis 22 is also the longitudinal axis of the device. The aperture allows optical access to the imaging system through the optical separator 4 which is mounted.

[0167] In a preferred embodiment, the fixed part 159 of the housing is coupled to the focused sound source 31 and used with the continuously adjustable part 45 of the housing so that the penetration depth 17 is continuously adjustable. In some embodiments, the adjustment range is from 0 mm to 1000 mm, and in some other embodiments, the adjustment range is from 0 to 20 mm. In some embodiments, the continuous adjustment is provided by the threaded coupling 46 so that the rotation of the adjustable part of the housing about the acoustic main axis 22 provides the relative movement of the adjustable part 45 of the housing along the acoustic main axis 22.

[0168] In addition, the fixed part of the housing is coupled to the handpiece housing 30, which includes a camera housing 26, which contains an image sensor 25 and a movable objective lens 115. The camera holder 26 allows the objective lens to move toward and away from the image sensor. It will be understood by those skilled in the art that the image sensor 25 is positioned so that its sensing surface coincides with the image plane 117 of the imaging system, as described above. In addition, once the reference plane of the housing 20 is coupled to the surface of the tissue to be treated, the object is the surface of the tissue to be treated, such as the skin surface.

[0169] Many embodiments disclosed herein adjust the penetration depth 17 by providing a continuously adjustable housing 45. It will be appreciated by those skilled in the art that each change in the penetration depth changes the distance of the reference plane 20, which is the same as the object plane 116 in a preferred configuration, to the image plane 117, which is the sensing surface of the image sensor 25 in a preferred configuration. In some embodiments, this means that the objective lens needs to be moved along the optical axis 130 to refocus the image. Equations (4) to (8) can be used to estimate the necessary displacement. In some embodiments, the movement of the objective lens 115 is provided by a threaded coupling 47.

[0170] Fig.24 An isometric three-dimensional cross-sectional view of an acoustic device with continuously adjustable penetration depth and optical viewing capabilities is shown. Similar to the previous embodiment, Fig.24The embodiment in FIG. 4 comprises a focused acoustic source 31 having a hole in its center along the acoustic principal axis 22. The hole allows optical access to the imaging system through the optical separator 4 where it is mounted.

[0171] In a preferred embodiment, the fixed member 159 of the housing is coupled to the focused sound source 31 and used with the continuously adjustable member 45 of the housing so that the penetration depth 17 is continuously adjustable. In some embodiments, the adjustment range is from 0 mm to 1000 mm, and in some other embodiments, the adjustment range is from 0 to 20 mm. In some embodiments, the continuous adjustment is provided by the threaded coupling 46 so that rotation 71 of the adjustable member 45 of the housing about the acoustic axis 22 provides relative movement 70 of the adjustable member 45 of the housing along the acoustic axis 22, such as Fig.33 As shown. The movement is continuous and reversible; therefore, the adjustment of the penetration depth is continuous and reversible. In some embodiments, the pitch of the threaded coupling 46 (the distance between corresponding points on adjacent threads) is selected to precisely control the penetration depth by rotating in direction 71. In some embodiments, the pitch is 0.01mm to 10mm, and in a preferred embodiment, the pitch ranges from 0.1mm to 5mm. The adjustment of the penetration depth changes the total volume of the impermeable chamber 166. In some embodiments, after adjustment, it is necessary to remove or add the coupling medium 58 through one or more refill ports. The refill port can be an opening 8, and the refilling of the coupling medium can involve removing the acoustic window 168. In a preferred embodiment, this is not necessary, and the volume change of the impermeable chamber 166 is compensated by the presence of a coupling medium buffer. In some embodiments, the buffer is in the form of a container hydraulically connected to the impermeable chamber 166. In a more preferred embodiment, the function of the coupling medium buffer is provided by a bubble trap 5. In some embodiments, the adjustment is controlled by a scale engraved or printed on the outside of the housing, i.e., on the fixed part 30 and the adjustable part 45 of the housing. In another embodiment, the control of the penetration depth adjustment is assisted by one or more distance or proximity sensors. The one or more sensors can adopt any principle, including but not limited to electric field principle, magnetic field principle, optical principle, etc.

[0172] Furthermore, the fixed part of the housing is coupled to the handpiece housing 30, which includes a camera housing 26 containing an image sensor 25 and a movable objective lens 115. The camera holder 26 allows the objective lens to be moved towards and away from the image sensor.

[0173] exist Fig.23In the embodiment shown, the adjustment movement of the objective lens 115 is provided by a threaded coupling 47. In a preferred configuration, a threaded fixture having a shoulder 50 forms a magnetic link 60 with an outer ring 48 through a system having two or more magnets 49. Turning the outer ring 48 can continuously adjust the optical imaging system so that the image remains sharp at any penetration depth ranging from 0 to 1000 mm.

[0174] Additional Configuration

[0175] Several embodiments disclosed herein may include electrically adjusting the penetration depth by incorporating one or more mechanical devices that provide motion (e.g., motors, piezoelectric motors, stepper motors, electromagnetic actuators, and other devices). Additionally, adjustment of the objective lens is also provided by one or more mechanical devices that provide motion (e.g., motors, piezoelectric motors, electromagnetic actuators, and other devices). In some other arrangements, optical focus is provided by at least one lens having an adjustable optical focal length. Fig.34 An embodiment disclosed herein is shown in which a rotor 81 of a motor 80 is mechanically coupled to an adjustable part 45 of a housing via a coupling 82. The housing of the motor 80 is attached to a fixed part 30 of the housing. Thus, the rotation 83 of the rotor 82 is converted into a rotation of the adjustable part 45 of the housing, and the adjustable part 45 of the housing provides adjustment of the penetration depth along the acoustic main axis 22 in the direction 70 via a threaded coupling 46. In some embodiments, the mechanical coupling 82 is coupled based on friction, and in some other embodiments, the mechanical coupling 82 is coupled based on gears, involving two or more gears. In yet another embodiment, the motor 80 is equipped with a gearbox to reduce the rotation speed and increase the torque, thereby providing precise adjustment of the penetration depth. In a preferred embodiment, the pitch of the threaded coupling 46 is combined with the rotation speed of the motor 80 via a gear system, configured to enable precise control of the penetration depth, wherein the resolution ranges from 0.001 mm to 100 mm, and in another configuration, the resolution ranges from 0.01 to 1 mm. The pitch of the threaded coupling 46 ranges from 0.01 mm to 100 mm, and in a more preferred configuration, the pitch of the threaded coupling 46 ranges from 0.1 to 10 mm. The speed of the motor 80 ranges from 1 rpm (revolutions per minute) to 10,000 rpm. In a more preferred configuration, the speed of the motor ranges from 10 rpm to 500 rpm.

[0176] Several embodiments may utilize autofocus algorithms that may be incorporated into the optical refocusing after adjusting the penetration depth.

[0177] In some embodiments, the penetration depth can be continuously adjusted during treatment according to a predetermined trajectory predetermined by diagnostic methods such as ultrasound imaging, magnetic resonance imaging, etc.

[0178] The real-time continuous imaging capability provided by the embodiments disclosed herein can be further used for image processing to provide additional information to the operator. Some embodiments can be configured so that the real-time image of the treated surface 200 is supplemented by a virtual overlay image 201 showing the location of the treatment point 205. In some embodiments, the overlay image can use different symbols to display information about the treated location and the location to be treated to assist the operator. Augmented reality algorithms or other closed-loop tracking algorithms can be used to track the moving image of the skin surface. In some embodiments, specific features of the skin (such as natural texture 203 and hair location 206) can guide the information to be superimposed.

[0179] In some embodiments, the superimposed graphics contain information about the treatment plan, such as the location of the POT and / or a virtual outline of the lesion 204, such as Fig.28 In addition, the virtual overlay information can be supplemented by data provided by other diagnostic methods, such as but not limited to ultrasound imaging, magnetic resonance imaging, etc. Fig.29 An example of a virtual overlay is shown that displays the outline of a blood vessel detected using, for example, ultrasound imaging.In some embodiments, an artificial intelligence algorithm is provided and implemented to assist in data fusion between the virtual overlay information and the diagnostic system.

[0180] Focus on the sound source

[0181] In general, in the embodiments described herein, any type of sound source 31 may be used. In a preferred embodiment, the focused sound source 31 comprises a piezoelectric element 3 made as part of a shell (e.g., a sphere) with a specific geometric focal length, the element thickness defining its thickness resonant frequency, and the diameter defining its aperture. In one embodiment, the focal length ranges from 5 to 500 mm, and the element thickness ranges from 0.01 mm to 20 mm, while the aperture ranges from 10 mm to 1000 mm. In another embodiment, the acoustic focal length ranges from 1 mm to 50 mm, and the element thickness ranges from 0.05 mm to 10 mm, while the aperture ranges from 1 mm to 200 mm.

[0182] Preferably, the acoustic focusing source has one or more holes that are equipped with an optical separator. In some embodiments, the hole is located at the center of the focusing source. In some other embodiments, the hole is located off-center. In many embodiments described herein, the hole in the focused acoustic source provides a clear optical path for optical observation of the surface of the tissue to be treated.

[0183] In a preferred embodiment, the focused sound source 31 may be a piezoelectric element having a hole 3. The piezoelectric element 3 may be made of a piezoelectric material such as doped lead zirconate titanate (PZT). PZT is preferred because it has good energy conversion properties (high coupling coefficient k 33 and high d33 value) and the cost is relatively low.

[0184] In other embodiments, the sound source 31 is made of alternative piezoelectric materials, such as but not limited to single crystals made of lithium niobate (LNb), aluminum nitride (AlN), lead magnesium niobate-lead titanate (PMN-PT) or quartz; polycrystalline ceramic materials made of lead metaniobate, potassium sodium niobate (KNN), barium titanate (BaT), bismuth titanate (BT), sodium bismuth titanate (BNT), sodium bismuth titanate-bismuth titanate (BNT-BT); or polymer materials made of polyvinylidene fluoride (PVDF).

[0185] In other embodiments, the focused acoustic source 31 may be replaced by an alternative active element, such as a capacitive micromachined ultrasonic transducer (CMUT), a piezoelectric micromachined ultrasonic transducer (PMUT), or the like.

[0186] In other embodiments, other materials, including combinations of materials and layers, may be used for the focused acoustic source 31. In other embodiments, the focused acoustic source 31 may be used for a piezoelectric composite material.

[0187] In some embodiments, the focused sound source 31 is a piezoelectric element 3, and the mechanical quality factor (Q m ) is higher than 1000. In other embodiments, a Q higher than 100 may be used. m .

[0188] In some embodiments, the focused acoustic source 31 is a planar element to which an additional element (acoustic lens) is attached for focusing the acoustic waves onto a defined focal point 21. In some configurations, the lens is made of a low acoustic loss material characterized by a sound velocity lower than the sound velocity in the coupling medium 58 (e.g. water). In this case, the lens is convex and is typically made of a polymer, such as PDMS (polydimethylsiloxane), which typically has a sound velocity of 950 m / s. In another configuration, the acoustic lens is concave and characterized by a sound velocity higher than the sound velocity in the coupling medium 58. This can be achieved by using a composite material, such as a polymer filled with a metal filler. In one embodiment, the polymer is an epoxy filled with a tungsten filler.

[0189] In other embodiments, the focusing of the ultrasound waves is achieved by other methods other than those described above, such as using electronic focusing techniques. In this configuration, the focused acoustic source 31 includes a plurality of piezoelectric elements driven by a multi-output power driver. Focusing is achieved by introducing a specific delay between each drive signal so that the focused wave reaches the acoustic focus 21 in a preset manner. In some embodiments, the multi-element transducer includes more than one element. In another embodiment, the transducer includes 2 to 256 elements.

[0190] Other lighting configurations

[0191] Some other embodiments disclosed herein include a plurality of light sources 11 coupled to the housing 1, which operate in different spectral ranges. In some embodiments, at least one light source operates in a spectral range of 450 μm to 850 μm, while other light sources (at least one) operate in a range of 200 μm to 500 μm. The light sources 11 can be turned on and off individually. In some embodiments, the light sources 11 can also be operated simultaneously. In another embodiment, the above-mentioned light source 11 is combined with another light source operating in a narrow spectral range of visible light (e.g., from 550 μm to 650 μm, from 450 μm to 550 μm, from 650 μm to 750 μm).

[0192] In some further configurations, the optical monitoring system includes at least one light polarization filter. The filter is placed in front of the objective lens 115 along the optical axis 130. In some embodiments, the optical separator 4 can be made to also serve as a light polarization filter. The polarization filter is then oriented relative to the light source to provide cross-polarization imaging, which is beneficial to the operator because it can eliminate glare and reflections from the imaging surface. In some other configurations, the polarization filter and the light source are oriented in the same direction to provide parallel polarization that only outlines surface features. In a preferred configuration, the direction of the polarized light relative to the polarization filter is controllable. In some embodiments, control is provided by a plurality of light sources distributed along the periphery of the housing. The light source is then turned on and off to provide a light pattern, resulting in controllable polarization of the light used for imaging.

[0193] Handpiece

[0194] Fig.35 Elements of a handpiece are shown. Those skilled in the art will appreciate that in several embodiments, the acoustic device operates in conjunction with a handpiece 302, which is sometimes referred to as an application member, probe, or wand. The handpiece comprises a portion of the treatment system 300 that is held by a medical professional administering the treatment during treatment. As described in several places herein (including with respect to Figure 4 ), the handpiece 302 may include a fixed member 159 and an adjustable member 161. In several embodiments disclosed herein, the fixed member 159 of the housing is coupled to the handpiece housing 30. In a preferred embodiment, the fixed member 159 of the housing is permanently attached to the handpiece housing 30, and the adjustable member 161 is removably coupled to the fixed member 159 of the housing.

[0195] In a preferred embodiment, the following elements are contained within the fixed portion 159 of the housing: focused acoustic source 31, optical separator 4, and electrical matching circuit 2. In a preferred embodiment, the handpiece controller 303, elements of the optical viewing subsystem (such as objective lens 115, image sensor 25, and auxiliary electronics 119) are located in the fixed portion 159 of the housing, or are housed in the handpiece housing 30.

[0196] In many embodiments disclosed herein, the separation plane 317 between the fixed part 159 of the shell and the adjustable part 161 of the shell can be located anywhere between the plane of the acousto-optic window 168 and the focused sound source 31. The fixed part 159 of the shell and the adjustable part 161 of the shell are coupled in such a way that they form an impermeable chamber 166 filled with a coupling medium 58. In some embodiments, the light source 11 is coupled to the fixed part 159 of the shell. In some other embodiments, the light source is coupled to the adjustable part 161 of the shell. In yet another configuration, some of the light sources are coupled to the fixed part 159 of the shell, while other light sources are coupled to the adjustable part 161 of the shell.

[0197] Treatment system

[0198] like Fig.30 As shown, the embodiments disclosed herein can be part of a treatment system 300. In some configurations, the system 300 includes a main unit 301 and a handpiece 302. The main unit 301 contains a main controller 304 and provides subsystems for the proper operation of the focus source 31, such as a frequency synthesizer 307, an RF (radio frequency) power supply 308 (RF power amplifier, RF power driver), and RF filtering and matching 309. Fig.30 In the illustrated embodiment, the main unit 301 and the handpiece 302 are both connected by means of a wired connection 310. In some configurations, the wired connection has the capability of conducting RF power signals and control and digital signals as well as a DC energy supply for the handpiece. In a preferred configuration, the wired connection provides an interface for presenting on a display 306 a continuously optically monitored skin surface during treatment.

[0199] In some other embodiments disclosed herein, such as Fig.31 , the treatment system 300 comprises a main unit 301 and a separate handpiece 316. The main unit provides a user interface and display functions. The separate handpiece is controlled via a wireless interface 314, which in a preferred configuration presents the skin surface that is continuously optically monitored during treatment on a display 306. The separate handpiece is powered internally by a battery 313.

[0200] In another configuration, such as Fig.32In the configuration schematically shown in FIG. 3 , the embodiments disclosed herein are part of a handheld therapeutic system 315. Fig.32 In the configuration shown, all necessary subsystems (controller, frequency synthesizer, RF power amplifier, RF filtering and matching) are built into the stand-alone handpiece 316. In addition, the display and user interface functions are also integrated into the stand-alone handpiece.

Claims

1. A sound generating system, comprising: a fixed component of the handpiece, wherein the fixed component includes a focused sound-emitting source having a fixed acoustic focal length; and a plurality of adjustable components for a handpiece, wherein each adjustable component of the plurality of adjustable components is designed to be removably and interchangeably coupled one at a time to a fixed component of the handpiece; Wherein, the penetration depth of the handpiece is adjusted by coupling different adjustable components among the plurality of adjustable components to the fixed component.

2. The sound generating system according to claim 1, wherein: The fixed portion of the handpiece also includes an optical system that images a treatment surface through any adjustable portion of the plurality of adjustable portions that is coupled to the fixed portion.

3. The sound generating system according to claim 2, wherein: The optical system comprises an objective lens and an imaging plane, and wherein a distance between the objective lens and the imaging plane along a longitudinal axis is adjustable.

4. The sound generating system according to claim 3, wherein: The distance is adjusted by mechanically moving the objective along its longitudinal axis towards or away from the imaging plane.

5. The sound generating system according to claim 2, wherein: The optical principal axis of the optical system is coaxial with the acoustic principal axis of the focused sound source.

6. The sound generating system according to claim 2, wherein: The optical system includes an imaging plane and at least one optical component having an adjustable optical focal length along a longitudinal axis.

7. The sound generating system according to claim 1, wherein: The fixed part of the handpiece contains a bubble trap with depths ranging from 0.1mm to 100mm.

8. The sound generating system according to claim 6, wherein: The adjustable optical focus is achieved by one of the following features: liquid lens, electrowetting, use of shape-changing polymers, and acousto-optic tuning.

9. The sound generating system according to claim 2, wherein: The penetration depth is adjustable within a range between at least 0 mm and 5 mm, and the optical depth of field of the optical system is equal to or greater than said range.

10. The sound generating system according to claim 2, wherein: The optical system has a principal optical axis including a portion that is not coaxial with the principal acoustic axis.

11. The sound generating system according to claim 1, wherein: An interface between a fixed component of the handpiece and any of the plurality of adjustable components passes through a chamber designed to contain a liquid acoustic coupling medium.

12. A sound generating system, comprising: a fixed component of the handpiece, wherein the fixed component includes a focused sound-emitting source having a fixed acoustic focal length; a plurality of adjustable components for a handpiece, wherein each adjustable component of the plurality of adjustable components is designed to be removably and interchangeably coupled to a fixed component of the handpiece one at a time and has a different length along a longitudinal axis; and an optical system attached within the fixed component of the handpiece, wherein the optical system is designed to image a treatment surface through any adjustable component of the plurality of adjustable components that is coupled to the fixed component; Wherein, the penetration depth of the handpiece is adjusted by coupling different adjustable components among the plurality of adjustable components to the fixed component.

13. The sound generating system according to claim 12, wherein: The optical system comprises an objective lens and an imaging plane, and wherein a distance between the objective lens and the imaging plane along a longitudinal axis is adjustable.

14. The sound generating system according to claim 13, wherein: The distance is adjusted by mechanically moving the objective along its longitudinal axis towards or away from the imaging plane.

15. The sound generating system according to claim 12, wherein: The optical principal axis of the optical system is coaxial with the acoustic principal axis of the focused sound source.

16. The sound generating system according to claim 12, wherein: The optical system includes an imaging plane and at least one optical component having an adjustable optical focal length along a longitudinal axis.

17. The sound generating system according to claim 16, wherein: The adjustable optical focus is achieved by one of the following features: liquid lens, electrowetting, use of shape-changing polymers, and acousto-optic tuning.

18. The sound generating system according to claim 12, wherein: The penetration depth is adjustable within a range between at least 0 mm and 5 mm, and the optical depth of field of the optical system is equal to or greater than said range.

19. The sound generating system according to claim 1, wherein: An interface between a fixed component of the handpiece and any of the plurality of adjustable components passes through a chamber designed to contain a liquid acoustic coupling medium.

20. A sound generating system, comprising: A fixing part of the handpiece; and a plurality of adjustable components for a handpiece, wherein each adjustable component of the plurality of adjustable components is designed to be removably and interchangeably coupled one at a time to a fixed component of the handpiece; Wherein, an interface between a fixed component of the handpiece and any adjustable component of the plurality of adjustable components passes through a chamber designed to contain a liquid acoustic coupling medium.

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