FIELD OF THE INVENTION

[0001] The invention generally relates to energy delivery devices for treating tissue with high-frequency energy and methods of forming an energy delivery device.

BACKGROUND

[0002] Certain types of energy delivery devices are capable of treating a patient’s tissue with electromagnetic energy. These energy delivery devices, which emit electromagnetic energy in different regions of the electromagnetic spectrum for tissue treatment, may be used to treat a multitude of diverse skin conditions. For example, the energy delivery device may non- ablatively and non-invasively treat a skin condition or other type of tissue condition.

[0003] One variety of these energy delivery devices emits high-frequency electromagnetic energy in the radio-frequency (RF) band of the electromagnetic spectrum. The high-frequency energy may be used to treat skin tissue by passing high-frequency energy through a surface of the skin, while actively cooling the skin to prevent damage to the skin’s epidermal layer closer to the skin surface. The high-frequency energy heats tissue beneath the epidermis to a temperature sufficient to denature collagen, which causes the collagen to contract and shrink and, thereby, tighten the tissue. Treatment with high-frequency energy also causes a mild inflammation. The inflammatory response of the tissue causes new collagen to be generated over time (between three days and six months following treatment), which results in further tissue contraction.

[0004] Typically, energy delivery devices include a treatment tip that is placed in contact with, or proximate to, the patient’s skin surface and that emits electromagnetic energy that penetrates through the skin surface and into the tissue beneath the skin surface. The non-patient side of the energy delivery device may include a component, such as an applicator with an electrode, for supplying high-frequency energy to the patient’s tissue. Traditional applicators include a flexible polymer film upon which an electrode is formed, typically on the non-patient side of the flexible polymer film. The patient side of the flexible polymer film typically includes laminated stepped frames consisting of polymer layers. During a treatment, the increasing thickness generated by the stepped laminates generates an outward electrical impedance gradient, thereby improving the spatial uniformity of the energy transferred from the electrode to the tissue. [0005] Although conventional energy delivery devices have proven adequate for their intended purpose, what is needed therefore are improved energy delivery devices for delivering high-frequency energy and methods of forming an energy delivery device.

SUMMARY

[0006] In an embodiment, an energy delivery device includes an applicator having an electrode and a substrate. The electrode includes a pad and a plurality of sections having a concentric arrangement about the pad. The sections have respective widths that decrease with increasing distance from the pad.

[0007] In an embodiment, a method of making an energy delivery device is provided. The method includes depositing a conductor on a substrate and patterning the conductor with photolithography and etching processes to define a pad and a plurality of sections having a concentric arrangement about the pad. The plurality of sections have respective widths that decrease with increasing distance from the pad.

[0008] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used in isolation as an aid in determining the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The accompanying drawings, which are incorporated in and constitute a part of this specification and in which like reference numerals refer to like features, illustrate embodiments of the invention and, together with a general description of the invention given above and the detailed description of the embodiments given below, serve to explain the principles of the invention. In the drawings, like reference numerals refer to like features in the various views.

[0010] FIG. 1 is a block diagram of an example energy-based therapeutic device that is suitable for implementing aspects of the invention described herein.

[0011] FIG. 2 is a plan view of an applicator in accordance with embodiments of the invention.

[0012] FIG. 3 is a cross-sectional view taken generally along line 3-3 in FIG. 2.

DETAIFED DESCRIPTION

[0013] With reference to FIGS. 1-3 and in accordance with embodiments of the invention, an energy-based therapeutic device 200 includes a system controller 210, a human-to-machine interface (“HM ) 220, a high-frequency generator 230, a power supply 240, a handpiece 250, and a treatment tip 260. The system controller 210 is generally configured to control the operation and functionality of the device 200 by controlling the other components of the device 200, such as the high-frequency generator 230 and the power supply 240. The system controller 210 is a high-level hardware controller that enables the application of high-frequency energy (e.g., radio-frequency (RF) energy) to a treatment area of a patient for use in, for example, a transcutaneous dermatological treatment. Lower level hardware controllers located in the other components of the device 200 may manage component-level operations under the direction and coordination of the system controller 210.

[0014] In controlling and orchestrating the operation of the other components, the system controller 210 may also monitor status messages received from the lower-level hardware controllers and various operational parameters during a procedure applying high-frequency energy to the treatment area. Examples of such operational parameters include: the peak/average output power emitted from the treatment tip 260, the temperature at the treatment tip 260, the patient-applied mechanical force, current values of usage data for the treatment tip, and the like. The system controller 210 may disable the application of high-frequency energy to the treatment area if the operational parameters or the status messages from the lower-level hardware controllers indicate a fault condition. For example, if a current value of usage data for the treatment tip 260 exceeds a threshold value, the system controller 210 will disable the application of high-frequency energy to the treatment area.

[0015] The HMI 220 provides an interface between an operator (e.g., a clinician) and the device 200 for exchanging commands, requests, information, data, and the like, which enable the operator to interact with the functionalities provided by the device 200. In an embodiment, the HMI 220 may include a touch-sensitive touch screen that provides both an input interface and an output interface between the operator and the device 200. In an embodiment, the HMI 220 may include an audio interface, such as a microphone and/or speaker. In an embodiment, the HMI 220 may include physical input devices, such as buttons (e.g., push buttons, rocker buttons, or other buttons known in the art), dials, slider switches, joysticks, click wheels, a keyboard, a pointer device (e.g., a mouse), and the like. The high-frequency generator 230 is configured to generate high-frequency energy (e.g., RF energy) for driving the electrode 12 in the treatment tip 260 when enabled by the system controller 210 and in accordance with commands received from an operator via the HMI 220. In an embodiment, the high-frequency energy may be radio- frequency energy in a range from one (1) megahertz (MHz) to twenty (20) megahertz.

[0016] The power supply 240 is configured to deliver electrical power from an external power source (e.g., an alternating current (“AC”) outlet) to the various components of the device 200. In an embodiment, the power supply 240 is configured to convert AC power obtained from an external power source into direct current (“DC”) power for delivery to the various components. In an embodiment, the power supply 240 may be configured to provide electrical isolation between the external power source and the other components of the device 200.

[0017] The handpiece 250 is configured to couple the treatment tip 260 to the other components of the device 200 along the high-frequency energy propagation path. The handpiece 250 is connected to the device 200 via a flexible conduit enclosing conductors that electrically couple the handpiece 250 to the other components. The handpiece 250 may be smoothly contoured for gripping and handling by a clinician serving as the operator, which permits the handpiece 250 to be grasped by at least one hand of the clinician for manipulating the location of the handpiece 250 and treatment tip 260. During a therapeutic procedure, an operator positions the handpiece 250 (and thereby the treatment tip 260 and its applicator 10) proximate to a treatment area of a patient and in contact with the treatment area. After contacting the treatment area with a portion of the treatment tip 260, as subsequently described, the operator may instruct the device 200 to deliver high-frequency energy from the applicator 10 to the treatment area by interacting with controls disposed on an outward surface of the handpiece 250 and/or controls at the console. For example, the handpiece 250 may include controls that enable the operator to initiate/terminate high-frequency energy delivery to the treatment area and/or adjust an amount of high-frequency energy that is applied to the treatment area.

[0018] The treatment tip 260 couples with the handpiece 250 to deliver high-frequency energy generated by high-frequency generator 230 to a patient for therapeutic purposes. The treatment tip 260 includes an applicator 10 that is designed to deliver the high-frequency energy in a specific density to the patient during the therapeutic procedure. The treatment tip 260 may include a housing in which the applicator 10 is contained and may be configured so as to be releasably attached to the handpiece 250. Sensor data indicative of a temperature at the treatment tip 260 may be obtained using temperature sensors (e.g., thermistors) included in the treatment tip 260. [0019] In an embodiment, at least a subset of the components forming the device 200 are contained within a console (or mechanical enclosure). For example, the console may contain the system controller 210, the high-frequency generator 230, and the power supply 240. In an embodiment, the handpiece 250 is physically coupled to the console via the flexible conduit enclosing conductors that electrically couple the handpiece 250 to the other components of the device 200. All or part of the HMI 220 may be disposed on an outward facing surface of the console.

[0020] A fluid delivery member 270 may be arranged inside the handpiece 250 and/or treatment tip 260. A supply of the coolant (e.g., a coolant canister) may be located at the console of the device 200 and coupled by tubing with the fluid delivery member 270. The fluid delivery member 270 may be configured to controllably deliver a spray or stream of a coolant to the applicator 10 in conjunction with a treatment procedure. The coolant may be triggered under the control of the system controller 210 to deliver the coolant spray or stream before, during, and/or after the delivery of the high-frequency energy from the applicator 10 to the patient’s tissue.

[0021] A vibration device 280 may be arranged inside the handpiece 250 and/or the treatment tip 260. The vibration device 280 is configured to oscillate or vibrate the treatment tip 260 and the applicator 10 at a relatively low frequency relative to the handpiece 250 and the treatment area. In particular, the vibration device 280 causes the treatment tip 260 to oscillate or vibrate in a path along an axis that is normal or substantially normal to the treatment area with at least a portion of the treatment tip 260 in contact with the treatment area to transfer the vibration to the treatment area. Without intending to be bound by any particular theory, it is believed that such vibration may provide a pain control mechanism for the patient during a treatment procedure.

[0022] Referring to FIGS. 2-3, the applicator 10 may include a substrate 14 and an electrode 12 that is positioned on the substrate 14. The electrode 12 of the applicator 10 may be contacted by, for example, pogo pins in treatment tip 260 or pogo pins in the handpiece 250 when the treatment tip 260 is coupled with the handpiece 250. The electrode 12 may be composed of a conductor, such as copper or aluminum. The electrode 12 may be applied to the substrate 14 by, for example, lamination, vapor deposition, sputter deposition, or another method, and may be patterned by photolithography and etching processes following application. Alternatively, the electrode 12 may be applied to the substrate 14 by a screen printing process. The substrate 14 is composed of a material that is an electrical insulator. The substrate 14 may be a film that is composed of a polymer, such as a flexible film that is composed of polyimide. In an alternative embodiment, the substrate 14 may be composed of a ceramic material, such as aluminum nitride, alumina, yttria stabilized zirconia (“YTZP” or“YSZ”), or a combination thereof.

[0023] In an embodiment, the substrate 14 may have a thickness, tl, that is substantially uniform between its front and rear surfaces, which may be substantially planar, over its entire form or shape. The substantially uniform thickness of the substrate 14 differs from conventional applicators in which the substrate has a non-uniform thickness. For example, the substrate of conventional applicators may include a frame that increases its effective thickness adjacent to the edges of the electrode 12. In an embodiment, the electrode 12 may have a thickness, t2, that is substantially uniform over its entire shape or form. In an embodiment, the thickness, t2, of the electrode 12 may be substantially equal to the thickness, tl, of the substrate 14. In an embodiment, the electrode 12 may be placed on surface of the substrate 14 such that the substrate 14 is arranged between the electrode 12 and the patient’s tissue during a treatment procedure.

[0024] The electrode 12 may include a pad 16 and sections 18, 20, 22, 24 that are arranged to surround the pad 16. The section 18 is arranged closest to the pad 16, and the section 24 is arranged most distant from the pad 16. The pad 16 may be centrally arranged on the substrate 14, the sections 18, 20, 22, 24 may have a centered arrangement relative to a geometrical center 13 of the pad 16, and the sections 18, 20, 22, 24 may be concentric. In an embodiment, the sections 18, 20, 22, 24 may be concentric about the center 13 of the pad 16. in an embodiment, the pad 16 and the sections 18, 20, 22, 24 may be symmetrically arranged about a normal axis extending through the center 13 of the pad 16. In alternative embodiments, the number of sections 18, 20, 22, 24 may be greater than or less than the number (i.e., four) shown in the representative embodiment of the electrode 12. The pad 16 may have a rectangular or square shape, and each of the sections 18, 20, 22, 24 of the electrode 12 may include strips that have a rectangular or square placement so as to form closed geometrical shapes each surrounding the pad 16 and having rectangular or square inner and outer perimeters or boundaries. The introduction of the sections 18, 20, 22, 24 that are arranged about the pad 16 differs from conventional electrodes used in transcutaneous energy delivery that only include a single region of conductor that is analogous to pad 16 alone. [0025] The pad 16 and the sections 18, 20, 22, 24 of the electrode 12 may be connected by short line segments or traces 26 such that all portions of the electrode 12 are connected in electrical continuity and provide a closed circuit. In this manner, the pad 16 of the electrode 12 may be contacted by, for example, pogo pins in the handpiece 250, when the treatment tip 260 is coupled with the handpiece 250 or in treatment tip 260 to permit the transfer of high-frequency energy to the electrode 12 during a treatment procedure, and the sections 18, 20, 22, 24 of the electrode 12 may receive high-frequency energy that is conducted from the pad 16 through the traces 26.

[0026] The sections 18, 20, 22, 24 and the pad 16 of the electrode 12 are separated by spaces or gaps 28 over which the conductor of the electrode 12 is absent and the electrical insulator of the substrate 14 is exposed. The gaps 28 are arranged between the respective inner and outer perimeters of the sections 18, 20, 22, 24 and between the inner perimeter of the section 18 and the outer perimeter of the pad 16. The traces 26 bridge and locally interrupt the gaps 28 such that the sections 18, 20, 22, 24 and the pad 16 of the electrode 12 are connected together.

Otherwise, the gaps 28 provide discontinuities in the electrode 12 between adjacent sections 18, 20, 22, 24 and also between the section 18 and the pad 16, and the traces 26 only cover a minor portion of the surface area of the substrate 14 exposed by the gaps 28. In an embodiment, the width, wO, of each of the gaps 28 may be substantially uniform at all locations between the different pairs of nearest-neighbor or adjacent sections 18, 20, 22, 24 and also between the section 18 and the pad 16. The value of the gap width may be selected based on tissue thermal conductivity to enhance tissue temperature uniformity across the area of the electrode 12.

[0027] The sections 18, 20, 22, 24 of the electrode 12 may have individual widths that depend upon the distance from the pad 16 and that are therefore unequal. In an embodiment, each of the sections 18, 20, 22, 24 of the electrode 12 may have a width, and these widths may decrease with increasing separation from the pad 16. In other words, the section 18 of the electrode 12 has the greatest width, wl, the section 24 of the electrode has the smallest width, w4, and the width, w3, of the section 22 is less than the width, w2, of section 20 and greater than the width, w4, of section 24. In an embodiment, the width, wl, of the section 18 may be substantially uniform along its strip length and about its closed geometrical shape, the width, w2, of the section 20 may be substantially uniform along its strip length and about its closed geometrical shape, the width, w3, of the section 22 may be substantially uniform along its strip length and about its closed geometrical shape, and/or the width, w4, of the section 24 may be substantially uniform along its strip length and about its closed geometrical shape. The progressive narrowing of the widths that provides a sufficiently uniform temperature field in the patient’s tissue may be determined empirically via finite element simulations modeling the energized and operating electrode 12.

[0028] The progressive narrowing of the width dimension of the sections 18, 20, 22, 24 of the electrode 12 causes the sections 18, 20, 22, 24 to have different capacitances during a tissue treatment when the electrode 12 is energized and high-frequency energy is being capacitively coupled through the substrate 14 and with the tissue. The variation in capacitance may provide an electrical impedance gradient that extends from the center 13 of the electrode 12 outward with the highest impedance occurring at or near the outer perimeter or periphery 21 at the edges of the electrode 12. The electrical impedance gradient, in turn, defines a temperature field in the tissue during tissue treatment near the electrode 12 that may exhibit substantial uniformity. In contrast, absent the impedance gradient, the temperature field may be non-uniform, with higher temperatures concentrated at or near the periphery 21 of the electrode 12.

[0029] References herein to terms modified by language of approximation, such as“about”, “approximately”, and“substantially”, are not to be limited to the precise value specified. The language of approximation may correspond to the precision of an instrument used to measure the value and, unless otherwise dependent on the precision of the instrument, may indicate +/- 10% of the stated value(s).

[0030] References herein to terms such as "vertical", "horizontal", etc. are made by way of example, and not by way of limitation, to establish a frame of reference. The term“horizontal” as used herein is defined as a plane parallel to a conventional plane of a semiconductor substrate, regardless of its actual three-dimensional spatial orientation. The terms“vertical” and“normal” refer to a direction perpendicular to the horizontal, as just defined. The term“lateral” refers to a direction within the horizontal plane.

[0031] A feature "connected" or "coupled" to or with another feature may be directly connected or coupled to or with the other feature or, instead, one or more intervening features may be present. A feature may be "directly connected" or "directly coupled" to or with another feature if intervening features are absent. A feature may be "indirectly connected" or "indirectly coupled" to or with another feature if at least one intervening feature is present. A feature "on" or "contacting" another feature may be directly on or in direct contact with the other feature or, instead, one or more intervening features may be present. A feature may be "directly on" or in "direct contact " with another feature if intervening features are absent. A feature may be "indirectly on" or in "indirect contact" with another feature if at least one intervening feature is present.

[0032] The descriptions of the various embodiments of the present invention have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.