Ultrasonic method and device for cosmetic applications

A combination of low frequency high amplitude sonic frequency vibrations and high frequency low intensity ultrasonic pressure waves are applied to cosmetic compounds and to the skin to promote improved penetration of the cosmetic compounds into the epidermis. The cosmetic applicator device includes means for generating both sonic frequency vibrations and ultrasonic pressure waves adopted to deliver cosmetic compounds into the epidermis safely without significant temperature rise in the skin. Various removable applicator and skin cleaning attachments are also disclosed, including some with ultrasound waveguide.

FIELD OF THE INVENTION

This invention relates to sonic and/or ultrasonic devices for cosmetic applications.

BACKGROUND OF THE INVENTION

The stratum corneum, the outermost layer of the epidermis consists of dead cells (corneocytes). The purpose of this layer of dead skin is to form a barrier to protect underlying living tissue from infection, dehydration, and chemical attacks.

Unfortunately, the same low permeability barrier characteristic of the stratum corneum, which protects the body from infections, also resists the penetration of beneficial cosmetic and chemical compounds, such as moisturizers, alpha-hydroxyl acids, collagen, vitamins and vasodilators. In addition, oily and congested skin conditions are also reducing the penetration of beneficial skin treatment compounds.

The invention is concerned with methods and apparatus facilitating the use of sonic and ultrasonic energy coupled to the skin to temporarily increase the permeability of the skin and enhance the absorption of beneficial cosmetic and chemical compounds into the skin, and particularly to direct and focus the ultrasound energy into small restricted areas such as the nose and face interface by the utilization of an ultrasound waveguide.

DESCRIPTION OF PRIOR ART

Numerous attempts have been made in the past to enhance the penetrations of cosmetic compounds into the skin by chemical, electrical and ultrasonic means.

The application of chemicals to modify the skin structure to allow the penetration of cosmetics was found to be dangerous because while it provided access for cosmetics to penetrate, it left the body unprotected against harmful environments, interacting with corneocytes causing irritation, erythema (red skin) and contact dermatitis.

The application of electrical fields to create transient transport pathways by a method called electroporation, and the method to electrically charge molecules to increase their penetration into the skin called iontophoresis (U.S. Pat. No. 6,169,920), have both been proven costly and ineffective. Electrical abrasion devices for increasing the skin's permeability (U.S. Pat. No. 8,386,027) remove some layers of the stratum corneum causing intense irritation and discomfort.

The effort of prior art of ultrasonically induced drug delivery (sonophoresis) described in U.S. Pat. No. 6,322,532 is focused in driving drug molecules through the skin by high frequency and high intensity ultrasonic pressure waves. This procedure suffers from the disadvantage of tissue heating and the associated modification and sometimes destruction of healthy cells.

To achieve a non tissue heating modality, ultrasound devices described by McDaniel (US 2001/0041856), Reed (US 2009/0318853 A1), and Bock (U.S. Pat. No. 5,618,275) are typically operate at 35 mW/cm2intensity and utilizing ultrasound transducers of 12 mm diameter and larger. While these devices are highly suitable for use on large flat surface areas of the face, these devices will not fit into and cannot apply the compounds into restricted areas such as the intersection of the face and the nose and particularly between the eyes and the nose. Merely creating a smaller device to fit into these restricted areas would defeat the purpose of having a general purpose application device for the larger flat areas of the face.

Notwithstanding the teaching of the prior art, the ability to deliver cosmetic compounds into the skin by a general purpose device for both in small and restricted areas and the large flat areas of the face safely and effectively has remained unsolved.

Responding to the above described unresolved needs, the object of this invention is to provide a general purpose skin care apparatus to safely increase the permeability of the stratum corneum and deliver cosmetic compounds deeply into the dermis in both the small and restricted areas and the large flat areas of the face.

SUMMARY OF THE INVENTION

As noted in the description of the prior art, the safety of the typical sonophoresis apparatus is compromised by the high intensity requirements of the process, resulting in excessive tissue heating and its associated consequences.

An objective of the invention is to improve the safety of typical sonophoresis apparatus to deliver cosmetic compounds into the dermis at reduced ultrasound intensity, particularly in small and restricted areas of the face, such as between the eyes and the nose.

The invention achieves this objective of utilizing lower intensity ultrasonic pressure waves by augmenting the ultrasonic pressure waves with non-tissue heating low frequency sonic vibrations applied to the skin in combination with the high frequency ultrasound. The low frequency sonic vibration component of this new method increases the permeability of the skin and allows a lower intensity non-tissue heating ultrasound component to drive the cosmetic compound through the stratum corneum into the dermis. Furthermore, since oils and various contaminants on the skin can reduce the penetration of cosmetic compounds, an optional pre treatment skin-cleansing step is part of the disclosed method. To reach into small and restricted areas, the invention utilizes slim metallic ultrasound waveguides.

In the above discussion, the terms cosmetic compounds and vasodilators includes but not limited to skin care products such as anti wrinkle lotions, moisturizers, antioxidant vitamins, alpha-hydroxyl acids, liposomes, collagen, elastin, hair growth and hair remover compounds and others.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1andFIG. 2show the invention of the ultrasonic cosmetic applicator20in a preferred configuration. The applicator20comprises a tubular shaped handle portion22, a neck portion24, and an applicator head portion26constructed of a rigid plastic material such as Acrylonitrile Butadiene Styrene (ABS), an ultrasound transducer28, a driving motor30, an eccentric weight32mounted on the output shaft of the driving motor30, an electronic module36, a battery pack38, and interconnecting wiring40.

The ultrasound transducer28is typically constructed of a piezo-electric ceramic material such as PZT-8 grade Lead Zirconate Titanate manufactured by Morgan Matroc, Inc., or similar products manufactured by numerous other entities. The construction of the ultrasound transducer28can be a single or a multiple element unit, as it is commonly practiced by people familiar in the art.

The ABS material utilized for the applicator20is due to the ABS excellent acoustic characteristics. However, numerous other rigid plastic materials could be substituted to achieve various cost and performance goals of the designers.

Control switch34energizes the driving motor30, which rotates the eccentrically mounted weight32between 2,000 and 25,000 RPM, ideal speed being at 9,000 RPM, generating a 33 to 417 Hertz sonic frequency rotational vibration44of the handle22and neck24portions of the applicator20, which is considered a relatively low sonic frequency vibration in the art, which defines sonic frequency vibration as being 10 to 20,000 Hertz. As shown inFIG. 2the cross section of the neck24is designed to be relatively thin in the vertical direction X compared to the lateral direction Y thereby significantly increasing the vertical vibration42amplitude of the applicator head26while significantly decreasing lateral vibration46amplitude of the applicator head26. In other words, the neck portion24of the applicator20is designed to be a motion transducer to convert the rotational vibration44of the handle22portion of the applicator20into a substantially vertical vibration42of the applicator head26, converting the rotational energy of the motor30into vertically vibrating energy of the applicator head26.

The battery pack38can be constructed as a single cell or multi cell battery pack, of various chemistries, such as Alkaline Manganese, Nickel-Cadmium, Ni-Mh, Lithium or other newer construction.

The major function of the electronic module36is to convert the low voltage DC power, typically 1.5 to 4.8 VDC, of the battery pack38into high voltage (4.8 to 60 Volt) typically sinusoidal wave ultrasonic frequency (typically 15 kHz to 20 MHz) DC power in a continuous wave or burst wave modality.

Simultaneously with energizing the driving motor30, switch34also activates the electronic module36. Through the interconnecting wiring40the electronic module36energizes the ultrasound transducer28which contracts and expands in tune with the high frequency DC power and converts this electronic power into ultrasonic pressure waves48at a typical intensity from 0.05 to 0.5 W/cm2.

InFIG. 3Athe applicator head26of the applicator20is shown in position on top of the outer surface of the stratum corneum52, consisting of flat dead cells filled with keratin fibers surrounded by ordered lipid bilayers54A shown in a relaxed position58. The ordered structure of the stratum corneum52and the ordered lipid bilayers54A are forming a normally almost impermeable skin structure. A thin layer of cosmetic compound50is shown to be disposed between the applicator contact surface92of the applicator head26and the stratum corneum52. A typically very limited amount of small molecules56of the cosmetic compound50are shown to be penetrating slightly into the ordered lipid bilayers54A without assistance from the applicator head26.

FIG. 3Bshows the applicator head26activated in the vertically vibrating42mode on top of the stratum corneum52and a thin layer of cosmetic compound50is shown to be disposed between the applicator contact surface92of the applicator head26and the stratum corneum52. The vertical vibration42of the applicator head26(also depicted with solid and dashed lines to illustrate vibration) repeatedly compresses and relaxes the stratum corneum52and the ordered lipid bilayers54A from the relaxed position58to the compressed position60in tune with the high amplitude low frequency vibration mode of the applicator head26. Under the repeated and continuing influence of this high amplitude low sonic frequency vibration42and the resulting repeated compression and relaxation cycles of the stratum corneum52and the ordered lipid bilayers54A, the ordered lipid bilayers54A beginning to disorganize and develop larger passage ways for the molecules56of the cosmetic compound50to pass through. The disorganized lipid bilayers54B are depicted with dashed lines.

FIG. 4shows the applicator head26in contact with the stratum corneum52while having a thin layer of cosmetic compound50disposed between the applicator contact surface92of the applicator head26and the stratum corneum52. The ultrasound transducer28is shown being energized by the electronic module36through the connective wiring40and radiating ultrasonic pressure waves48into the stratum corneum52and the disorganized lipid bilayers54B. While the sonophoresis art has been demonstrated to work in the frequency range of 20 kHz to 20 MHz and in both of a continuous wave and a burst wave modality, it is important to select the right combination of frequency, driving voltage, and modality to match the size and characteristics of the piezo electric transducer selected for the system. Hard piezo materials such as the PZT8 formulation will output high ultrasonic power intensities with the associated heating of tissues when driven by high voltages. To avoid overheating the tissue, a 20% duty cycle (20% on 80% off) burst modality has been proven helpful in prior art.

Now, according to the invention, safety of the sonophoresis process can be further enhanced by the simultaneous application of a non tissue heating high amplitude low sonic frequency mechanical vibration42and the ultrasonic pressure waves48to the stratum corneum52. Due to the presence of the high amplitude low sonic frequency vibration42applied to the stratum corneum52, which establishes the initial pathways through the stratum corneum52, the intensity of the ultrasonic pressure waves48can be reduced significantly, resulting in proportional reduction of tissue heating, while maintaining the effectiveness of the process.

The high frequency ultrasonic pressure waves48, as shown inFIG. 4, penetrate the disorganized lipid bilayers54B much deeper than the lower sonic frequency vibrations42do. These ultrasonic pressure waves48in a preferred frequency range of 20 kHz to 2 MHz and in a 20% duty cycle burst modality are developing mild cavitation deep within the lipid bilayers54B resulting in microscopic air and/or vacuum pockets66which act to further break up the organized lipid bilayers54A shown inFIG. 3Ainto disorganized lipid bilayers54B, generating more and deeper passage ways for the cosmetic compound molecules56to penetrate through the stratum corneum52, through the disorganized lipid bilayers54B, through the bottom layer of the epidermis62and into the dermis64.

FIG. 5shows a longitudinal cross section of an alternative configuration of the invention wherein the applicator80comprises a tubular shaped handle portion82terminating in an angular applicator head portion90constructed of a rigid plastic material such as Acrylonitrile Butadiene Styrene (ABS), an ultrasound transducer28, a driving motor30, an eccentric weight32mounted on the output shaft of the driving motor30, an electronic module36, a battery pack38, and interconnecting wiring40.

The ultrasound transducer28is typically constructed of a piezo-electric ceramic material such as PZT-8 grade Lead Zirconate Titanate manufactured by Morgan Matroc, Inc., or similar products manufactured by numerous other entities. The construction of the ultrasound transducer28can be a single or a multiple element unit, as it is commonly practiced by people familiar in the art.

The ABS material utilized for the applicator80is due to the ABS excellent acoustic characteristics. However, numerous other materials could be substituted to achieve various cost and performance goals of the designers. For example, the applicator contact surface92may be constructed of stainless steel or other metallic material.

Control switch34energizes the driving motor30, which rotates the eccentrically mounted weight32between 2,000 and 25,000 RPM, ideal speed being at 9,000 RPM, generating a 33 to 417 Hertz sonic frequency rotational vibration44of the handle portion82of the applicator80.

The angular positioning87of the applicator contact surface92of the applicator head portion90acts as a motion transducer converting the rotational vibration44of the handle portion82into an angular rotational vibration84of the applicator contact surface92of the applicator head portion90. The angular rotational vibration84creates a two dimensional vibration motion of the applicator contact surface92in the directions of motion vector86and motion vector88.

WhileFIG. 5depicts an angularly fixed applicator head portion90construction, applicator80can also be constructed having a user adjustable angular applicator head portion90wherein the user can vary the angular positioning87of the applicator contact surface92to increase or decrease the vibratory motion in the directions of motion vector86and motion vector88. A decreasing angle87will decrease the vibration amplitude of motion vector88and increase the vibration amplitude of motion vector86.

The battery pack38can be constructed as a single cell or multi cell battery pack, of various chemistries, such as Alkaline Manganese, Nickel-Cadmium, Ni-Mh, Lithium or other newer construction.

The major function of the electronic module36is to convert the low voltage DC power, typically 1.5 to 4.8 VDC, of the battery pack38into high voltage (4.8 to 60 Volt) typically sinusoidal wave ultrasonic frequency (typically 15 kHz to 20 MHz) DC power in a continuous wave or burst wave modality.

Simultaneously with energizing the driving motor30, switch34also activates the electronic module36. Through the interconnecting wiring40the electronic module36energizes the ultrasound transducer28which contracts and expands in tune with the high frequency DC power and converts this electronic power into ultrasonic pressure waves48at a typical intensity from 0.05 to 0.5 W/cm2.

The embodiment of the invention as applicator80depicted inFIG. 5functions the same way as the embodiment of the invention as applicator20depicted inFIGS. 1, 2, 3A, 3B, and 4. More particularly, the sonic frequency vibration of the applicator contact surface92of the applicator head portion90in the direction of motion vector86described inFIG. 5functions the same way as the sonic frequency vibration of the applicator contact surface92of applicator head portion26in the direction of motion vector42described inFIG. 3BandFIG. 4. The ultrasonic pressure waves48radiated from applicator80described inFIG. 5function the same way as the ultrasonic pressure waves48radiated from applicator head26described inFIG. 4. The underlying science of the two embodiments are identical.

FIG. 6shows a applicator head98designed to conduct the low frequency orbital vibration84and vibration motion vectors86and88and the ultrasound pressure waves48into the hard convex areas of the anatomy, such as the scalp, the elbows, and similar areas.

The applicator contact surface92of the applicator head portion90as described earlier inFIG. 5is typically made of rigid or semi rigid material designed for soft flexible surfaces of the anatomy, such as the cheeks, where the anatomy conforms to the applicator contact surface92under slight pressure and transmission of the ultrasonic pressure waves48to the anatomy is easily achieved. However, when the flat rigid applicator contact surface92is applied to a hard convex area, such as the scalp, it results in a very small single point contact, which limits the transmission of the ultrasonic pressure waves to the anatomy.

To maximize transmission of the ultrasonic pressure waves48to the hard convex areas of the anatomy the applicator head98is made of a flexible ultrasound conductive material such as silicone rubber and features a concave contact surface96which easily conforms to the anatomy under slight pressure. The thickness of the soft silicone rubber material at the central point must be minimized in the sub-millimeter region to minimize ultrasound attenuation losses by the soft silicone rubber material. To further assure excellent transmission of the ultrasound pressure waves48from the ultrasound transducer28to the applicator head98a slight coating of ultrasound conductive material such as water or contact gel can be applied between the applicator contact surface92and the removable applicator head98.

The applicator head98design depicted inFIG. 6can be executed either as permanently fixed to the applicator80or constructed to be easily removable for replacement or exchange with other optional accessories of the device.

FIG. 7Ashows a simple inexpensive cone shaped applicator head100designed for concave areas of the anatomy. Such small concave areas as between the eyes and the nose or between the cheeks and the nose are typically not accessible by the flat applicator contact surface92of the applicator head portion90of applicator80designed for larger soft surfaces of the anatomy. The applicator head100is constructed of flexible materials, such as flexible silicone rubber conducting the low frequency orbital vibration84and vibration motion vectors86and88and the ultrasound pressure waves48into these small concave areas. While the conical shape of the applicator head100allows the contact with the restricted areas, the ultrasound pressure waves48must travel through a long path of 20 mm or longer ultrasound attenuating flexible plastic material, which significantly attenuates the ultrasound pressure waves48emitted by transducer28, reducing the effectiveness of the device.

The applicator head100design depicted inFIG. 7Acan be executed either as permanently fixed to the applicator80or constructed to be easily removable for replacement or exchange with other optional accessories of the device.

FIG. 7Bdepicts a solution to the excessive ultrasound pressure waves48attenuation described inFIG. 7A, which eliminates the attenuation of the ultrasound pressure waves48emitted by the ultrasound transducer28and allow the ultrasound pressure waves48to reach the small and restricted areas between the eyes and the nose practically un-attenuated. The invention employs a conically shaped non-attenuating ultrasound waveguide122insert within the applicator head120made of metal such as aluminum, titanium or similar metals in solid contact with the flat applicator surface92of the applicator head portion90of the device. Aluminum or titanium metal is preferred for the waveguide due to their light weight and their non-attenuating characteristic of the ultrasound pressure waves48. The waveguide122is a long aspect ratio design, typically having a ratio of 4 to 1 or larger between the length A and the tip diameter B. The larger base diameter of the waveguide122is designed to match the size of the ultrasound transducer28in the applicator head portion90of the device. Tip diameter B is typically ranges between 4 mm and 6 mm. The tapered construction of waveguide122focuses the acoustic energy from the larger ultrasound transducer28into the smaller tip diameter B and increases the efficiency of the device.

The shell of the applicator head120surrounding and securing the metallic ultrasound waveguide122is typically made of a flexible material, such as silicone rubber to provide a pleasant tactile feeling for the user. Dimension C shown at the tip of the applicator head120should be minimized to 1 mm or less to reduce the attenuation of the ultrasound pressure waves48reaching the skin of the user.

The applicator head120design depicted inFIG. 7Bcan be executed either as permanently fixed to the applicator80or constructed to be easily removable for replacement or exchange with other optional accessories of the device.

FIG. 8shows a removable cleansing brush head112installed on the applicator head portion90of applicator80. The brush head112is typically constructed of a semi rigid ABS plastic material housing multiple tufts of bristles114. As described in detail inFIG. 5the applicator motor30vibrates the applicator head portion90in an orbital vibration84pattern. This orbital vibration84is transferred to the brush head112and the plurality of bristle tufts114. When energized through the interconnecting wiring40the ultrasound transducer28generates and emits ultrasound pressure waves48which are conducted by the applicator contact surface92to the brush head112and the bristle tufts114and radiated from the bristle tufts114to the skin of the user. Applying slight pressure of the orbitally vibrating84bristle tufts114against the skin the user effectively cleansing the skin by the synergistic scrubbing action of the bristle tufts114and the ultrasound pressure waves48radiated by the bristle tufts114.

FIG. 8also shows an optional construction of the applicator head portion90incorporating a stainless still cup110.

While the preceding description contains much specificity, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of preferred and additional embodiments thereof. Skilled artisans will readily be able to change dimensions, shapes, and construction materials of the various components described in the embodiments and adopt the invention to various types of sonic and ultrasonic energy applications. For example, additional removable and interchangeable applicators for enhanced cleansing of the skin such as sponges, cotton pads, lotion dispensers enhanced by the sonic and ultrasonic frequency motion of the applicator head are possible. Accordingly, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their legal equivalents.