GB2565139A

GB2565139A - Cryotherapy device

Info

Publication number: GB2565139A
Application number: GB1712568.3A
Authority: GB
Inventors: Henry Rhys Nathan Asher; Andre Da Silva Salvador Fabio
Original assignee: R N Ventures
Current assignee: R N Ventures
Priority date: 2017-08-04
Filing date: 2017-08-04
Publication date: 2019-02-06
Also published as: GB201712568D0

Abstract

A cryotherapy device 100 comprising: a waterproof housing 110 defining an internal volume; a cold plate 120, part of which forms an exterior surface 125; a thermoelectric module 130 e.g. Peltier element and a heat sink 140, both located in the internal volume. Both the cold plate and heat sink are thermally coupled to the thermoelectric module, allowing thermal energy to be absorbed from the cold plate and transferred to the heat sink. The heat sink can be arranged to dissipate heat through part, or most, of the housing. A thermal insulator, e.g. an air gap, may be located between the heat sink and the housing. The heat sink and/or cold plate may have a primary portion(s) 140P, 120P in direct thermal contact with the thermoelectric module and secondary portion(s) 140, 120 thermally coupled to the thermoelectric module via the respective primary portion(s). The volume of the heat sink may be greater than the cold plate. Also disclosed is a cryotherapy device (figures 7 and 8) comprising a cold plate with exterior surface having two different radii of curvature (R1, R2). The two radii may be located perpendicularly and R2 may be less than, or half of R1.

Description

TECHINCAL FIELD

This disclosure is in the field of cryotherapy devices. Particularly, but not exclusively, this disclosure relates to portable, handheld cryotherapy devices.

BACKGROUND

Cryotherapy devices have one or more treatment surfaces to cool a user's skin. Cooling an area of a user's skin briefly starves the skin of oxygenated blood flow and, consequently, causes a diversion of oxygenated blood flow which helps to improve cell function and cell turnover, flush out cellular toxins, and produce collagen and elastin.

A treatment surface of the cryotherapy device is cooled by a thermoelectric module (for example, a Peltier element) absorbing thermal energy received by the treatment surface from a user's skin, and transferring the thermal energy to a heat sink of the device.

Conventional cryotherapy devices use a fan to circulate air over the heat sink to adequately cool the device, as shown in patent publication US 2015/0121900 Al. This cryotherapy device is not able to be used in wet or very humid conditions, thus, the environments in which such cryotherapy devices can be used are restricted.

The invention aims to solve or at least mitigate the problem of the prior art.

SUMMARY OF THE INVENTION

According to an aspect of the invention, there is provided a cryotherapy device. The cryotherapy devices comprises a waterproof housing defining an internal volume of the cryotherapy device. The cryotherapy device comprises a cold plate and a section of the cold plate is an exterior surface of the cryotherapy device. The cryotherapy device also comprises a thermoelectric module located within the internal volume. The thermoelectric module is thermally coupled to the cold plate in order to cool the cold plate by absorbing thermal energy from the cold plate. The cryotherapy device further comprises a heat sink located within the internal volume and thermally coupled to the thermoelectric module. The thermoelectric module transfers thermal energy from the cold plate to the heat sink.

Advantageously, a cryotherapy device having a waterproof housing allows the device to function when used in a bath or shower environment. This provides a versatile device that is convenient to use.

In addition, the waterproof housing allows the cryotherapy device to be coupled with any other skincare device that requires water, creams, or lotions, providing a versatile device that can be used in various wet or humid environments.

Optionally, the waterproof housing is formed of a non heat conductive material. Optionally, the waterproof housing is formed of plastic.

Optionally, the heat sink is arranged in relation to the waterproof housing such that the thermal energy transferred to the heat sink from the thermoelectric module dissipates from the heat sink through the waterproof housing.

Advantageously, the arrangement of the heat sink allows thermal energy to efficiently dissipate out of the device through the waterproof housing, allowing the device to be operated for a sufficient time without overheating. In addition, use of the waterproof housing to dissipate heat in this way avoids the need for ventilation holes or an air circulating means to be incorporated into the device, thus, allowing the device to be waterproof.

Optionally, the heat sink is arranged in relation to the waterproof housing such that the thermal energy dissipates through a majority of a surface area of the waterproof housing. Arranging the heat sink and waterproof housing so that thermal energy dissipates through a majority of a surface area of the waterproof housing beneficially allows efficient dissipation of thermal energy out of the device, and, consequently, allows the device to be operated for a sufficient time without overheating and becoming uncomfortable for a user to operate.

Optionally, the heat sink is arranged within the internal volume such that a thermal insulator is provided between the heat sink and the waterproof housing. Optionally, the thermal insulator may be an air gap.

Beneficially, arranging the heat sink within the internal volume defined by the waterproof housing such that a thermal insulator is present between the heat sink and the waterproof housing restricts the rate of heating of the waterproof housing thereby making the device comfortable to hold.

Optionally, the air gap has a width in at least one of the following ranges: from 0.5 mm to 5.0 mm; from 1.0 mm to 4.0 mm; from 1.5 mm to 3.0 mm; from 2.0 mm to 2.5 mm.

Optionally, the heat sink has a volume sufficient to absorb the total thermal energy absorbed by the thermoelectric module from the cold plate.

Optionally, the heat sink has a volume larger than the volume of the cold plate.

Having the volume of the heat sink larger than the volume of the cold plate provides an optimal size of the heat sink that achieves a rate of heat dissipation that allows for sufficient cooling of the cold plate. In addition, the rate of dissipation achieved provides a cryotherapy device that is compact and that does not heat up to an uncomfortable or inoperable temperature.

Optionally, the heat sink is shaped to define a space for locating at least one component of the cryotherapy device, within the internal volume of the waterproof housing. The heat sink may be shaped to provide an enclosure such that the space defined by the heat sink is internal to the heat sink. Optionally, the heat sink may fully enclose the space for locating at least one component. Alternatively, the heat sink may not fully enclose the space and has at least one opening. Optionally, the heat sink has a top face and at least one side face extending from the top face, where the at least one opening is located on the at least one side face. Alternatively, the opening may replace a portion of the at least one side face such that the heat sink has at least one open side.

Optionally, the heat sink has a sleeve-like shape. Optionally, the heat sink is an opensided shape, for example, an open-ended container such as a cup having one or more open sides. Optionally, the heat sink has a helmet shape with an open side face and open end face, such as an open bottom face.

Advantageously, having the heat sink shaped to define a space suitable for locating a component of the device (for example, having a sleeve-like shape) serves to create a compact device that easily fits within a hand of a user and which optimises the shape of the heat sink to have a larger surface area closer to the waterproof housing through which thermal energy can be efficiently dissipated.

Optionally, the cryotherapy device comprises at least one component located within the space defined by the heat sink. Optionally, the at least one component is located wholly or partially within the space defined by the heat sink. Optionally, the at least one component includes at least one of the following: a battery; a vibrating motor; a support motor; and a printed circuit board.

Optionally, the heat sink comprises a primary portion in direct thermal contact with the thermoelectric module and a secondary portion thermally coupled to the thermoelectric module via the primary portion.

Optionally, the primary portion is located on a protruding portion of the heat sink.

Optionally, the secondary portion has a surface area larger than the surface area of the primary portion by a factor in one of the following ranges: greater than 1; from 1 up to and including 2; from 2 up to and including 3; from 3 up to and including 4; from 4 up to and including 5.

Having a larger surface area of the portion of the heat sink not coupled directly to the thermoelectric module than the surface area of the heat sink directly coupled to the thermoelectric module advantageously increases the speed of heat dissipation from the device, which avoids the device heating up to either an inoperable temperature or an uncomfortable temperature for a user holding the device.

Optionally, the cold plate comprises a primary portion in direct thermal contact with the thermoelectric module and a secondary portion thermally coupled to the thermoelectric module via the primary portion. Optionally, the primary portion is located on a protruding portion of the cold plate. Optionally, at least a part of the secondary portion of the cold plate is the section of the cold plate that is an exterior surface of the cryotherapy device.

Optionally, the waterproof housing has a collar, and the cold plate is arranged in relation to the collar such that at least a part of the secondary portion of the cold plate is the section of the cold plate that is an exterior surface of the cryotherapy device.

Optionally, the secondary portion of the heat sink has a surface area larger than the surface area of the secondary portion of the cold plate by a factor in one of the following ranges: greater than 1; from 1 up to and including 2; from 2 up to and including 3; from 3 up to and including 4; from 4 up to and including 5.

Having the surface area of the cold plate portion not coupled directly to the thermoelectric module to be larger than the portion directly coupled to the thermoelectric module provides a larger cooling surface for a user to engage with, which improves the interaction of the user with the device.

Optionally, the primary portion of the heat sink has a surface area equal to the surface area of the primary portion of the cold plate.

Optionally, the surface area of the secondary portion of the heat sink is in at least one of the following ranges: > 10,000 mm²; > 13,000 mm²; > 15,000 mm²; and > 21,000 mm².

Optionally, the surface area of the primary portion of the heat sink is equal to the surface area of the thermoelectric module in contact with the heat sink.

Optionally, the surface area of the secondary portion of the cold plate is in the range of greater than or equal to 1 and less than or equal to 1.5 times the surface area of the surface area of the thermoelectric module in contact with the cold plate.

Optionally, the surface area of the secondary portion of the cold plate is in at least one of the following ranges: > 1000 mm²; > 2000 mm²; > 3000 mm²; > 3500 mm².

Having a surface area of the secondary portion of the cold plate in the range of greater than or equal to 1 and less than or equal to 1.5 times the surface area of the thermoelectric module in contact with the cold plate provides an optimal size of the cold plate and rate of cooling of the same, and, in doing so, provides a cryotherapy device that provides sufficient and uniform cooling of a user's skin and thus, improves operation of the device whilst avoiding hot spots in the cold plate.

Optionally, the heat sink has a mass in one of the following ranges: from 80 g to 350 g; from 100 g to 330 g; from 150 g to 300 g; from 200 g to 260 g; and from 220 g to 245 gOptionally, the heat sink has a mass in the range from 100 g up to and including 300 g.

Advantageously, a heat sink with a mass in the range of 100 g to 300 g provides a comfortable device that is easily held by a hand of a user for a desired operational time.

Optionally, the heat sink has a mass that allows the volume of the heat sink to be sufficient to absorb the total thermal energy absorbed by the thermoelectric module from the cold plate.

Optionally, the mass of the heat sink is defined by the amount of energy generated by the thermoelectric module, the specific heat capacity of the material of the heat sink, and the temperature gradient between ambient room temperature and maximum room temperature of the thermoelectric module.

Optionally, the mass of the heat sink is greater than 5 times the mass of the cold plate or greater than 7 times the mass of the cold plate.

Optionally, the maximum mass of the heat sink is 10 times the mass of the cold plate.

Optionally, the cold plate has an external treatment surface defined by a first radius of curvature and a second radius of curvature, wherein the first radius of curvature and the second radius of curvature are different.

Advantageously, using a curved treatment surface provides a greater mass of the cold plate at the centre of the cold plate compared to the edges of the cold plate, this provides efficient and uniform cooling that avoids production of heat spots and increases the length of time that the cold plate is at a sufficiently cold temperature to provide treatment to a user.

Beneficially, a cold plate shaped using two different radii of curvature improves the usability of the device on an eye region of a user and thus improves the quality of treatment a user experiences. The device can easily fit into the shape of an eye socket of a user whilst engaging with (and consequently treating by cooling) an increased area of skin of the user.

Optionally, the first radius of curvature is perpendicular to the second radius of curvature.

Optionally, the second radius of curvature is less than the first radius of curvature.

Optionally, the second radius of curvature is less than or equal to half of the first radius of curvature.

Optionally, the first radius of curvature has a length in one of the following ranges: from 20 mm to 30 mm; from 31 mm to 40 mm; from 41 mm to 50 mm; from 51 mm to 60 mm; from 61 mm to 70 mm; from 71 mm to 80 mm; from 81 mm to 90 mm; and from 91 mm to 100 mm.

Optionally, the second radius of curvature has a length in one of the following ranges: from 20 mm to 30 mm; from 31 mm to 40 mm; and from 41 mm to 50 mm.

According to a further embodiment of the invention, there is provided a cryotherapy device comprising a treatment plate, wherein an exterior surface of the treatment plate is defined by a first radius of curvature and a second radius of curvature. The first radius of curvature is different to the second radius of curvature.

Beneficially, a treatment plate shaped using two different radii of curvature improves the usability of the device on an eye region of a user. The device can easily fit into the shape of an eye socket of a user whilst covering (and consequently treating by cooling) an increased area of skin of the user.

Optionally, the treatment plate is a cold plate.

Optionally, the first cross section is perpendicular to the second cross section.

Optionally, the second radius is less than the first radius.

Optionally, the second radius is less than or equal to half of the first radius.

Optionally, the first radius has a length in one of the following ranges: from 50 mm to 60 mm; from 61 mm to 70 mm; from 71 mm to 80 mm; from 81 mm to 90 mm; and from 91 mm to 100 mm.

Optionally, the second radius has a length in one of the following ranges: from 20 mm to 30 mm; from 31 mm to 40 mm; and from 41 mm to 50 mm.

BRIEF DESCRIPTION OF DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of a cryotherapy device, in accordance with an embodiment of the invention.

Figure 2 is a cross-sectional view ofthe cryotherapy device of Figure 1 along line A-A, in accordance with an embodiment ofthe invention.

Figure 3 is a closer cross-sectional view of the cryotherapy device of Figure 2.

Figure 4 is a perspective view of the heat sink of Figures 1 to 3, in accordance with an embodiment ofthe invention.

Figure 5 is a diagram ofthe components within the cryotherapy device of Figures 1 and 2, in accordance with an embodiment of the invention.

Figure 6 is a flow chart representing a control method, in accordance with an embodiment of the invention.

Figure 7 is a side view of the cryotherapy device of Figure 1.

Figure 8 is a further side view of the cryotherapy device of Figure 1.

DETAILED DESCRIPTION

An embodiment of the invention is now described.

Figure 1 is a perspective view of a cryotherapy device 100 according to an example embodiment.

The cryotherapy device 100 is a hand-held device that can be operated and held by a single hand of a user. The device 100 is also portable and rechargeable.

The cryotherapy device 100 has a waterproof housing 110 defining an exterior surface and an internal volume of the cryotherapy device 100. The cryotherapy device 100 also has a cold plate 120 arranged in relation to the waterproof housing 110 such that an external section 125 of the cold plate 120 is also an exterior surface of the cryotherapy device 100. The cold plate 120, or, more specifically, the external section 125 is a treatment surface of the device 100 used to cool the skin of a user.

Treating an area of user's skin through cooling constricts the capillaries which in turn briefly starves the area of oxygenated bloodflow. This firstly helps to tighten skin and reduce the appearance of open pores, which is very beneficial following hot cloth or deeppore cleansing such as that from a mechanical cleansing brush. Constriction of capillaries also helps calm any redness and swelling from the stimulating massage effect of such brushes, which, due to continual skin contact, are known to cause an over-stimulation of bloodflow due to the accoustic pressure on the surface of the skin.

In addition, the cold area mimics an injury and consequently the body diverts oxygenated bloodflow to stimulate 'healing'. This natural oxygenation can help to improve cell function, cell turnover, flush out cellular toxins, produce collagen and elastin and improve overall skin health.

The waterproof housing 110 has a sleeve 111 and a collar 112. The sleeve 111 is engaged with the collar 112 to define the internal volume. The sleeve 111 is engaged with the collar 112 to form a flush outer surface of device 100. The collar 112 is arranged to surround the external section 125 of the cold plate 120 to ensure that external section 125 is an exterior surface of the cryotherapy device 100.

The waterproof housing 110 is formed of plastic. The use of waterproof housing 110 allows the process of ultrasonic welding to be used to join the collar 112 to the sleeve 111 to create a waterproof and air tight device 100.

Optionally, a gasket may also be used to seal the collar 112 to the sleeve 111.

The cryotherapy device 100 also has a button 160 located on the housing 110, specifically, located on sleeve 111 of housing 110. The button 160 can be pressed by a user in order for a user to operate the cryotherapy device 100 and start treatment.

The underside of the cryotherapy device 100 may have a further treatment surface. For example, a vibrational sonic-cleansing surface. This is discussed in more detail in relation to Figure 2.

Figure 2 is a cross-sectional view of the cryotherapy device 100 of Figure 1 along line AA. The cryotherapy device 100 is engaged with a charging dock 200.

The cryotherapy device 100 has a thermoelectric module 130 located within the internal volume and thermally coupled to the cold plate 120 in order to cool the cold plate 120 by absorbing thermal energy from the cold plate 120. The cryotherapy device 100 also has a heat sink 140 located within the internal volume and thermally coupled to the thermoelectric module 130. The thermoelectric module 130 transfers thermal energy from the cold plate 120 to the heat sink 140.

The thermoelectric module 130 is a Peltier element. The thermoelectric module 130 has an optimum cooling direct current of 2.3 Amps at 5 Volts.

A thermoelectric paste (not shown) is used between the cold plate 120 and the thermoelectric module 130 to increase cooling efficiency of the cold plate 120 by removing any air gaps that may be present between the cold plate 120 and the thermoelectric module 130.

The cold plate 120 has a protruding portion 120P on the lower surface of the cold plate 120. The protruding portion 120P is in direct thermal contact with the thermoelectric module 130.

Optionally, a clamping means, such as one or more screws, may be used to further increase cooling efficiency by further reducing the likelihood of air being present between the cold plate 120 and the thermoelectric module 130. Equally, thermoelectric paste and/or a clamping means can also be used between the thermoelectric module 130 and the heat sink 140.

The heat sink 140 has a protruding portion 140P on the upper surface of the heat sink 140. The protruding portion 140P is in direct thermal contact with the thermoelectric module 130.

The heat sink 140 is arranged in relation to the waterproof housing 110 such that the thermal energy transferred to the heat sink 140 from the thermoelectric module 130 dissipates from the heat sink 140 through the waterproof housing 110. In more detail, the heat sink 140 is arranged in relation to the waterproof housing 110 such that the thermal energy dissipates through a majority of a surface area of the waterproof housing 110.

This arrangement allows the cold plate 120 to cool sufficiently to allow treatment of a user's skin. For example, a treatment temperature of the cold plate 120 may be between 4-8 Celsius (°C).

The heat sink 140 has a volume sufficient to absorb the total thermal energy absorbed by the thermoelectric module 130 from the cold plate 120.

The heat sink 140 has a volume larger than the volume of the cold plate 120.

The heat sink 140 has a mass that allows the volume of the heat sink 140 to be sufficient to absorb the total thermal energy absorbed by the thermoelectric module 130 from the cold plate 120.

The mass of the heat sink 140 is defined by the amount of energy generated by the thermoelectric module 130, the specific heat capacity of the material of the heat sink 140, and the temperature gradient between ambient room temperature and maximum room temperature of the thermoelectric module 130.

The heat sink 140 is also arranged within the internal volume such that an air gap 115 is provided between the heat sink 140 and the waterproof housing 110. More specifically, the heat sink 140 is arranged within the internal volume such that an air gap 115 is provided between the heat sink 140 and the sleeve 111 of the housing 110. The air gap 115 may have a width in the range from 2.0 mm to 2.5 mm. Alternatively, the air gap 115 may have a width in at least one of the following ranges: from 0.5 mm to 5.0 mm: from 1.0 mm to 4.0 mm: and from 1.5 mm to 3.0 mm.

The cryotherapy device 100 has a battery 161 coupled to the thermoelectric module 130.

The cryotherapy device 100 also has a plurality of components arranged to provide vibrational-sonic cleansing. In more detail, the cryotherapy device 100 has a brush 164 arranged at the opposite end of the device to the cold plate 120 and coupled to a vibrating motor 162 to provide vibrational-sonic cleansing. The brush 164 is located on the underside of the cryotherapy device 100 and provides a further treatment surface, in addition to the cold plate 120 that engages with a user's skin to provide treatment. The vibrating motor 162 is also coupled to the battery 161. The battery 161 is charged when the cryotherapy device 100 is engaged with the charging dock 200.

The cryotherapy device 100 also has a support structure 165 within the internal volume defined by the housing 110. The support structure 165 provides support to the battery 161, the vibrating motor 162, the button 160, and a printed circuit board 163.

Figure 3 is a closer cross-sectional view of the cryotherapy device of 100 of Figure 2.

The heat sink 140 has a primary portion 141 in direct thermal contact with the thermoelectric module 130. The heat sink 140 also has a secondary portion 142 thermally coupled to the thermoelectric module 130 via the primary portion 141. The secondary portion 142 is for dissipating thermal energy transferred to the heat sink 140 from the thermoelectric module 130.

The secondary portion 142 has a surface area larger than the surface area of the primary portion 141.

The heat sink 140 has an L-shaped cross section along the line A-A of Figure 1. The protruding portion 140P of the heat sink 140 has the primary portion 141 of the heat sink 140 and is in complete contact with the lower surface of the thermoelectric module 130.

Like the heat sink 140, the cold plate 120 also has a primary portion 121 in direct thermal contact with the thermoelectric module 130. The primary portion 121 is on the protruding portion 120P of the cold plate 120. The cold plate 120 also has a secondary portion 122 thermally coupled to the thermoelectric module 130 via the primary portion 121. The secondary portion 122 is for treating a user's skin by cooling.

The secondary portion 142 of the heat sink 140 has a surface area larger than the surface area of the secondary portion of the cold plate 122.

The primary portion 141 of the heat sink 140 has a surface area equal to the surface area of the primary portion 121 of the cold plate 120.

The mass of the heat sink 140 is defined by the amount of energy generated by the thermoelectric module 130, the specific heat capacity of the material of the heat sink 140, and the temperature gradient between ambient room temperature and maximum room temperature of the thermoelectric module 130. The heat sink 140 has a mass in the range from 40 g up to and including 45 g.

Figure 4 is a perspective view of the heat sink 140 in a slight variation to the heat sink described in relation to Figures 2 and 3 due to lack of the protruding portion 140P.

The heat sink 140 is shaped to define a space for locating at least one component of the cryotherapy device 100. In more detail, the heat sink 140 defines an unenclosed volume. The heat sink 140 has a helmet shape with an open bottom face and an open side face. Consequently, the heat sink 140 has an inverse U-shaped cross section along line B-B of Figure 1.

The helmet shape of the heat sink 140 is defined by a top plate 145 and a wall 146 extending from, and perpendicular to, the top plate 145. The space internal to the top plate 145 and the wall 146 can be used to locate at least one component of the cryotherapy device 100. The top plate 145 is generally quadrilateral with rounded corners between each side. As an alternative, the corners may be squared off. In this instance, the wall 146 defines three sides 143 having two indents 144 which increase the surface area of each side 143. The indents 144 are located on an exterior surface of each side 143 in order to be positioned closest to the housing 110 within device 100. The wall 146 has rounded corners between each of the sides 143.

As is illustrated by Figure 2, the cryotherapy device 100 has at least one component located within the space defined by the heat sink 140. In this example, the battery 161 and the vibrating motor 162 are both located partially within the space defined by the heat sink 140.

Figure 5 is a circuit diagram of a plurality of components within the cryotherapy device

100. A controller 167 is coupled to a driver 166 of the thermoelectric module 130. In this case, the thermoelectric module 130 is a peltier element 130 and the driver is a peltier driver 166. The controller 167 is also coupled to a hot temperature sensor 168 and cold temperature sensor 169. The peltier element 130 has a hot side and a cold side. The hot temperature sensor 168 is positioned in relation to the hot side of the peltier element 130 in order to measure the temperature of the hot side. The cold temperature sensor 169 is positioned in relation to the cold side of the peltier element 130 in order to measure the temperature of the cold side.

The hot temperature sensor 168 and the cold temperature sensor 169 feedback their respective measurements to the controller 167. The measurements obtained by the hot temperature sensor 168 and the cold temperature sensor 169 are compared, by the controller 167, to temperature thresholds, and, as a result of such comparisons further action may or may not be taken by the controller 167. For instance, the controller 167 determines from the cold temperature sensor 169 whether the device 100 is cold enough for a user to start treatment using the cold plate 120. The controller 167 can also determine from the hot temperature sensor 168 whether the device 100 is too hot for a user to operate, for example, the device may be too hot to provide effective treatment to a user.

A temperature threshold for the cold temperature sensor 169 may be a use threshold that defines when the cold plate 120 is cool enough to provide treatment. The use threshold may be, for example, 34°C and below.

A temperature threshold for the hot temperature sensor 168 may be a threshold that defines when the device 100 is too hot to be used by a user. The threshold may be, for example, 48°C, so that temperatures above the threshold are not reached.

In more detail, the controller 167 uses a proportional integral derivative (PID) control loop to reduce the measured cold temperature by the cold temperature sensor 169 towards a cold set point. A pulse width modulation technique is used to drive the peltier driver 166 by the controller 167 in order to reduce the cold temperature of the cold plate 120 to the cold set point. The cold set point is the optimum cold temperature for providing treatment. As an example, the cold set point may be 10°C for cooling treatment.

Figure 6 is a flow chart of a control method 300. The control method 300 is carried out by the controller 167 in order to determine what, if any, action should be taken to enable a user to operate the device 100 for treatment. The method 300 comprises measuring 320, using a temperature sensor, a temperature of the heat sink 140. After a measurement has been taken determining 340 whether the temperature of the heat sink 140 is less than or equal to a threshold, and, thus, whether the device 100 is sufficiently cool to be operated by a user. If the determination 340 determines that the temperature of the heat sink 140 exceeds the threshold, powering off 350 device 100 to allow the device 100 to cool. Otherwise, measuring 360, using a further temperature sensor, the temperature of the cold plate and determining 370 whether the cold plate 120 is less than or equal to a use threshold so that treatment may be started. If the cold plate 120 has a temperature less than or equal to the use threshold, starting 380 treatment. Otherwise, cooling 390 the cold plate 120 towards the cold set point.

Figure 7 is a side view of the cryotherapy device 100 of Figure 1. The device 100 of Figure 7 is a slight variation to the device 100 of Figure 1, in that that housing 110 has been removed. The device 100 has a cold plate 120 for treatment defined by a first radius of curvature, Rl. In more detail, the first radius of curvature, Rl, defines a radius of curvature of the exterior surface 125 of the cold plate 120.

Figure 8 is a side view of a further side of the cryotherapy device 100 of Figure 7. The side view of Figure 8 is a 90° anticlockwise rotation of the view illustrated by Figure 7. The cold plate 120 is defined by a second radius of curvature, R2. The first and second radii of curvature are different. The first and second radii of curvature Rl, R2 define the surface 125 of cold plate 120 across different cross sections of the device 100. In this example, the first radius of curvature, Rl is defined along a cross section of the device 100 that is rotated through 90° in relation to the cross section associated with the second radius of curvature, R2.

Advantageously, using a curved treatment surface provides a greater mass of the cold plate at the centre of the cold plate compared to the edges of the cold plate, this provides efficient and uniform cooling that avoids production of spots and increases length of time that the cold plate is at cold temperature.

The first radius of curvature Rl is larger than the second radius of curvature R2, and, as can be seen from Figure 7, the first radius of curvature, Rl, provides a flatter exterior surface 125 of the cold plate 120 compared to the second radius of curvature, R2, which provides a steeper curve, as illustrated in Figure 8. The second radius of curvature, R2, may be less than or equal to half of the first radius of curvature, Rl.

One or more of the heat sink, cold plate, and housing may be made from an aluminium alloy have a very small percentage of nickel, commonly known in the industry as nickelfree aluminium alloy. As an example, the aluminium alloy used may be ADC14. Ideally, the low percentage of nickel avoids skin allergy reaction in a user. The heat sink and/or cold plate may be formed by die casting using the nickel-free aluminium alloy.

Whilst the heat sink has been described as having an inverse U-shaped cross section, the heat sink may have any cross-sectional shape that defines a space. For example, the heat sink may be a cube, cuboid, or cylinder, either defining a wholly enclosed internal volume, or, instead, being sleeve-like with at least one open end or side.

Whilst the thermoelectric module is described as having an optimum cooling current of 2.3 Amps at 5 Volts, these values may change depending on the mass and/or volume of each of the cold plate and the heat sink.

In a slight variation, the external shape of the cold plate used for treatment may be defined by three or four radii of curvature.

Each radius of curvature may be associated with a circular shape or an elliptical shape.

Optionally, the first and second radius of curvature may be associated with cross sections of the device that are separated by one of the following: 10°; 20°; 30°; 40°; 50°; 60°; 70°; and 80°.

The treatment surface of the cold plate may form a part of the housing. The treatment surface may occupy one of the following proportions of a surface area of the housing of the cryotherapy device: 100%; between 80% and 99%; between 60% and 79%; and over 50%.

The button may be flush, protruding from, or sub-flush in relation to the plane of the surface area of the housing.

Each side of the heat sink may have a plurality of indents, protrusions, or both, or none. The indents and/or protrusions may be placed on an interior or exterior surface of the heat sink.

The arrangement/configuration of the cryotherapy features and the vibrational sonic cleansing features may be reversed. The vibrational sonic cleansing features may be replaced by an alternative skincare technology.

The device may have a timer that times for a desired treatment time when the device is in operation. The user may receive feedback (audio, haptic and/or visual) when the treatment time has completed. The timer may switch off the device when time of operation exceeds a predetermined safety threshold to avoid heating of the device to an unsafe temperature.

Claims

1. A cryotherapy device (100) comprising:

a waterproof housing (110) defining an internal volume of the cryotherapy device (100);

a cold plate (120) arranged in relation to the waterproof housing (110) such that a section (125) of the cold plate (120) is an exterior surface of the cryotherapy device (100);

a thermoelectric module (130) located within the internal volume and thermally coupled to the cold plate (120) in order to cool the cold plate (120) by absorbing thermal energy from the cold plate (120);

a heat sink (140) located within the internal volume and thermally coupled to the thermoelectric module (130), wherein the thermoelectric module (130) transfers thermal energy from the cold plate (120) to the heat sink (140).

2. The cryotherapy device (100) of claim 1, wherein the heat sink (140) is arranged in relation to the waterproof housing (110) such that the thermal energy transferred to the heat sink (140) from the thermoelectric module (130) dissipates from the heat sink (140) through the waterproof housing (110).

3. The cryotherapy device (100) of claim 2, wherein the heat sink (140) is arranged in relation to the waterproof housing (110) such that the thermal energy dissipates through a majority of a surface area of the waterproof housing (11).

4. The cryotherapy device (100) of any preceding claim, wherein the heat sink (140) is arranged within the internal volume such that a thermal insulator is provided between the heat sink (140) and the waterproof housing (110).

5. The cryotherapy device (100) of claim 4, wherein the thermal insulator is an air gap (115), wherein the air gap (115) has a width in at least one of the following ranges: from 0.5 mm to 5.0 mm; from 1.0 mm to 4.0 mm; from 1.5 mm to 3.0 mm; from 2.0 mm to 2.5 mm.

6. The cryotherapy device (100) of any preceding claim, wherein the heat sink (140) is shaped to define a volume for locating at least one component (150) of the cryotherapy device (100), within the internal volume of the waterproof housing (110).

7. The cryotherapy device (100) of claim 6, wherein the cryotherapy device (100) comprises at least one component (150) located within the volume defined by the heat sink (140).

8. The cryotherapy device (100) of any preceding claim, wherein the heat sink (140) comprises a primary portion in direct thermal contact with the thermoelectric module (130) and a secondary portion thermally coupled to the thermoelectric module (130) via the primary portion.

9. The cryotherapy device (100) of any preceding claim, wherein the cold plate (120) comprises a primary portion in direct thermal contact with the thermoelectric module (130) and a secondary portion thermally coupled to the thermoelectric module (130) via the primary portion.

10. The cryotherapy device (100) of claim 9, wherein at least a part of the secondary portion of the cold plate (120) is arranged in relation to the waterproof housing (110) to be an exterior surface of the cryotherapy device (100).

11. The cryotherapy device (100) of claim 9 or 10, when dependent on claim 8, wherein the secondary portion of the heat sink (140) has a surface area larger than the surface area of the secondary portion of the cold plate (120) by a factor in one of the following ranges: greater than 1; from 1 up to and including 2; from 2 up to and including 3; from 3 up to and including 4; from 4 up to and including 5.

12. The cryotherapy device (100) of any of claims 9 to 11, when dependent on claim 8 wherein the primary portion of the heat sink (140) has a surface area equal to the surface area of the primary portion of the cold plate (120).

13. The cryotherapy device (100) of any preceding claim, wherein the heat sink (140) has a volume sufficient to absorb the thermal energy absorbed by the thermoelectric module (130) from the cold plate (120).

14. The cryotherapy device (100) of claim 13, wherein the heat sink (140) has a larger volume than the cold plate (120).

15. The cryotherapy device (100) of any preceding claim, wherein the heat sink (140) has a mass in one of the following ranges: from 20 g to 40 g; from 41 g to 50 g; from 51 g to 70 g; and from 71 g to 90 g.

16. The cryotherapy device (100) of claim 15, wherein the heat sink (140) has a mass in the range from 40 g up to and including 45 g.

17. The cryotherapy device (100) of any preceding claim, wherein the cold plate (120) has an external treatment surface defined by a first radius of curvature, Rl, and a second radius of curvature, R2, wherein the first radius of curvature, Rl, and second radius of curvature, R2, are different.

18. The cryotherapy device of claim 17, wherein the first radius of curvature defines a plane of the external treatment surface that is rotated 90° to a plane of the external treatment surface defined by the second radius of curvature.

19. The cryotherapy device (100) of claim 17 or 18, wherein the second radius of curvature, R2, is less than the first radius of curvature, Rl.

20. The cryotherapy device (100) of claim 19, wherein the second radius of curvature, R2, is less than or equal to half of the first radius of curvature, Rl.

21. A cryotherapy device (100) comprising:

a cold plate (120):

wherein the cold plate (120) has an exterior surface (125) defined by a first radius of curvature, Rl, and a second radius of curvature, R2, wherein the first radius of curvature, Rl, and second radius of curvature, R2, are different.

22. The cryotherapy device 100 of claim 21, wherein the first radius of curvature defines a plane of the exterior surface (125) that is rotated 90° to a plane of the exterior surface (125) defined by the second radius of curvature.

23. The cryotherapy device (100) of claim 21 or 22, wherein the second radius of curvature, R2, is less than the first radius of curvature, Rl.

24. The cryotherapy device (100) of claim 23, wherein the second radius of curvature, R2, is less than or equal to half of the first radius of curvature, Rl.

25. The cryotherapy device (100) of any of claims 21 to 24, wherein the first radius of curvature, Rl, has a length in one of the following ranges: from 50 mm to 60 mm; from

61 mm to 70 mm; from 71 mm to 80 mm; from 81 mm to 90 mm; and from 91 mm to

100 mm.

26. The cryotherapy device (100) of any of claims 21 to 25 , wherein the second radius

5 of curvature, R2, has a length in one of the following ranges: from 20 mm to 30 mm; from

31 mm to 40 mm; and from 41 mm to 50 mm.