US20210322205A1

US20210322205A1 - Device for the treatment of itching and herpes diseases with a contact sensor

Info

Publication number: US20210322205A1
Application number: US17/273,190
Authority: US
Inventors: Daniel Bünger von Wurmb
Original assignee: Dermapharm AG
Current assignee: Dermapharm AG
Priority date: 2018-09-05
Filing date: 2019-09-05
Publication date: 2021-10-21
Also published as: EP3846754B1; WO2020049071A1; US20210322204A1; WO2020049070A1; PT3846754T; KR20210058863A; ES2950010T3; EP3846753A1; PL3846754T3; JP2022500105A; CN112638335A; JP2021534918A; CN112638336A; EP3846753B1; TW202023486A; EP3846754A1; KR20210062024A; ES2935492T3

Abstract

The invention relates to a device for treating itching and/or herpes disease on a skin, wherein a control device is configured to regulate a treatment surface on an outer side facing the skin by heating at least one heating element in a heating phase to a contact temperature during a contact of the treatment surface with the skin and to maintain the temperature in a treatment phase, and wherein the device comprises at least one contact sensor.

Description

BACKGROUND AND STATE OF THE ART

Itching (pruritus) is a subjectively unpleasant sensory perception related to the skin or mucous membrane. It can be localized or affect the entire body. Itching is often accompanied by a burning, stinging or tingling sensation, which the affected person often tries to relieve by scratching, rubbing, pressing, kneading or rubbing. Therefore, itching frequently leads to further pathological manifestations of the skin such as scratch marks, open wounds, crust formation and skin infections. The state of the art assumes that itching is mediated by pain receptors in the skin and is transmitted to the brain via the autonomic nervous system. The causes of itching can be very diverse. In addition to dry skin, lack of hydration or allergies, itching can also be caused by external agents and skin irritation, such as bites from mosquitoes or contact with cnidarians. Itching can be a reaction to chemical, mechanical or thermal stimuli. From a medical point of view, the causes or underlying diseases that lead to itching span a wide spectrum of dermatological and internal diseases.
A number of medications or cosmetic products are known for the medicinal treatment of the symptoms of itching. Essential oils, in particular menthol, thymol or camphor, are used to produce a short-term cooling effect. Skin care products such as creams or lotions can also have an analgesic effect by increasing the moisture content of the skin. In addition, antihistamines are helpful therapeutic options.
However, it is also known from the prior art to reduce the triggering of an itch by introducing a quantity of heat into the insect bite. A device for local, thermal treatment of mosquito bites in particular is described in EP 1231875 B1 and WO 01/34074 A1. For this purpose, a heating plate is brought to a maximum temperature from a range of 50 to 65° C. in the heating phase and maintained at this temperature for a treatment period of 2-12 sec. The control device shall ensure a tolerance of less than ±3° C. The possible applications of hyperthermic treatment further extend to herpes diseases. From DE 102005002946 A1 a device for the treatment of herpes diseases is known. The heat application leads on the one hand to a containment of the multiplication of the causative pathogens by a neutralizing effect on the herpes simplex viruses. On the other hand, the short-term heat treatment leads to a masking of the itching of the herpes disease by stimulating temperature-sensitive nerves.
Likewise, devices for a hyperthermic treatment of itching as well as herpes diseases are known from WO 2018/011262 A1 (or EP 3 269 340 A1) and WO 2018/011263 A1, which suggest targeted temperatures and treatment durations depending on the application.
WO 2006/125092 A2 discloses a device for the local treatment of skin disorders by means of a heat application. The focus of WO 2006/125092 A2 is to provide a replaceable cap for the device. Temperature regulation is achieved by means of a thermistor, which is installed in the vicinity of the treatment surface.
U.S. Pat. No. 6,245,093 B1 relates to a device for treating itching by means of heat. Treatment temperatures are disclosed for itching within a wide window of 46° C. and 62° C. The temperatures are measured by a temperature sensor and monitored by a controller, aiming to control the temperature of the treatment surface within ±1° C.
WO 2007/082648 A1 describes a device for treating insect bites or stings by applying heat. The device comprises a flat body as a contact surface, which may be made of ceramic or gold, among other materials. The temperature is controlled passively via a temperature-dependent resistor and a manual switch for starting and stopping the treatment preferably in a range of 50° C.-65° C.
The devices for hyperthermal treatment known from the prior art are characterized by a wide range of applications for alleviating the symptoms of insect bites, herpes diseases, jellyfish stings or other diseases associated with itching. However, the devices also exhibit disadvantages.
When heating the heating plates typically used in the known devices, subjectively perceived temperature fluctuations and a strong perception of pain can occur due to excessively high temperatures. It was recognized by the inventors that this is due in particular to an insufficiently known and therefore too imprecisely controlled contact temperature during treatment. The associated temperature fluctuations, especially in the event of the contact temperature overshooting the defined treatment range, can cause subjects to discontinue treatment and reduce the success of the therapy.

OBJECTIVE OF THE INVENTION

The objective of the invention was to provide a device which eliminates the disadvantages of the prior art. In particular, a device is to be provided which is suitable for the treatment of itching or herpes disease and is characterized by a safe and more precise control, increased effectiveness, application comfort as well as associated user compliance.

SUMMARY OF THE INVENTION

In a preferred embodiment, the invention thus relates to a device for treating itching and/or herpes disease on a skin, comprising

- a) at least one treatment surface and
- b) a control device for regulating the temperature of the treatment surface,
  characterized in that the control device is configured to regulate the treatment surface on an outer side facing the skin by heating at least one heating element in a heating phase to a contact temperature during a contact of the treatment surface with the skin and to maintain the contact temperature in a treatment phase, and wherein the device comprises at least one contact sensor.

In order to carry out a hyperthermic treatment, the control device according to the invention ensures that the treatment surface is brought to a contact temperature, e.g. of 43-47° C., during a contact of the treatment surface with the skin by heating at least one heating element. In the sense of the invention, the contact temperature designates the temperature which the treatment surface has on an outer side facing the skin while the latter is in contact with the skin site. According to the invention, a distinction is therefore preferably made between a contact temperature and a non-contact temperature of the treatment surface. Here, the non-contact temperature means the temperature of the treatment surface when it does not contact the skin but without thermal load, for example, only contacts air.
In known hyperthermal devices, the temperature of the treatment surface is typically regulated by a heating element on the basis of a non-contact temperature. That means the parameters of the control devices are determinded on the basis of standardized measurements of a temperature curve without thermal load. In the case of such control, no distinction is necessarily made between a regulation of the temperature of the treatment surface on the side facing the skin or the side facing away from the skin.
The inventors recognized that such a control is not sufficiently precise, especially when treating sensitive areas. The control can result in fluctuations and subjectively strongly perceived pain, which leads to a reduced compliance of the test persons (willingness of the test persons to actively participate) and thus to a reduced success of the therapy.
In particular, such control is not sufficiently precise for the treatment of e.g. herpes disease on sensitive areas such as the lips, for which the device is preferably suitable. Due to the thinner skin, physiological damage occurs more easily on the lips, for example. Moreover, consequently the sensitivity to pain is higher. The particularly precise regulation of the temperature can also lead to excellent results for the treatment of itching in the case of insect bites on thinner areas of skin, such as the face, the back of the hand or the insides of the arms.
For the purposes of the invention, the term “outer side of the treatment surface” refers to the side of the treatment surface which is accessible from the outside of the device and thus corresponds to the side which faces the skin, when the device is used. The use of term “an outer side of the treatment surface facing the skin” is predominantly explanatory. For a hyperthermic device, an outer side and inner side of the treatment surface will be always defined. The inner side preferably refers to the side facing away from the skin. In the case of a housing, it will be preferred that the treatment surface is integrated into the housing surface, whereby the inner side, in contrast to the outer side, is not accessible or visible from the outside.
To adjust the precise contact temperature, the device may have temperature sensors that measure the temperature of the treatment surface during a contact with the skin and regulate the heating elements accordingly. In cases where a temperature sensor does not measure the temperature of the treatment surface directly on the outer side facing the skin, for example, because it is installed on the inner side of a treatment surface, the target temperature of the control device for the measured value of the temperature sensor can be adjusted so that the contact temperature is precisely maintained in the predetermined range. For example, a correspondingly higher target temperature can be set based on experimental tests or calculations of the heat flow. This ensures that the contact temperature is present, when the treatment surface comes into contact with the skin. Advantageously, experiments have been able to show that the skin of a human being has similar thermal properties across different test subjects, so that the experimental or theoretical results can be reliably transferred. Likewise, it has been shown in particular that the thermal properties of the same extremities of a subject are often very similar, so that these thermal properties can be used to determine the contact temperature. For example, a device may be suitable for treating particular extremities, such as the lips, and may take into account their thermal properties. Also, the extremities to be treated may be preferentially set or automatically detected so that their properties may be taken into account in a treatment.
During the cycle of a hyperthermic treatment, the outer surface of the treatment surface facing the skin is first brought to the contact temperature in a heating phase. It is preferred that the heating phase does not require a longer period of time. Preferably, the heating phase should not exceed 10 s, and particularly preferably not more than 3 s. Excellent results have been obtained with heating times of 1-3 seconds. Following the heating phase, the contact temperature is maintained for the duration of the treatment phase. It may be preferred that the contact temperature is constant during the treatment phase. However, it may also be preferred that the contact temperature varies within specified limits during the treatment phase.
In the sense of the invention, the treatment phase preferably means a continuous period of time during which the control device maintains the side of the treatment surface facing the skin at a contact temperature within a predetermined range, e.g. from 43-47° C. Before the treatment phase, i.e. during the heating phase, the contact temperature is below said values. After completion of the treatment phase, heating of the at least one heating element by the control device preferably no longer occurs, so that the contact temperature falls below the predetermined range. A treatment phase can last, for example, 1 to 10 seconds.
By regulating the outer sided of the treatment surface to a predetermined contact temperature, a defined amount of heat is applied to the skin site in a controlled manner. The defined heat pulse leads to a surprisingly effective therapy of itching and herpes diseases, especially cold sores, without unpleasant pain or even burning.
Studies have shown that at a temperature level of, for example, 44° C. to 51°, the risk of a burn increases by a factor of two with each degree Celsius. Test persons also report that from a temperature of 47.5° C. to 48.5° C. heat is perceived on a skin in the form of a stabbing pain. Below 47° C., the temperature preference appears much more bearable.
In contrast, it has been recognized, for example, that thermolability of the DNA-binding protein ICP8 can be exploited to effectively inhibit replication of herpesvirus DNA. Studies demonstrate a reduction in the binding activity of the protein to viral DNA by approximately 50% at a temperature of 45° C. In particular, it has been recognized that a particularly strong masking of the itch sensation can be achieved when the thermo- and capsaicin receptor TRPV1 is locally activated in the affected skin areas. TRPV1 is involved in acute heat-induced pain in healthy skin and regulates, for example, the heat sensation at temperatures around 45° to 50° C. Activation of TRPV1 additionally suppresses feelings of tension and itching and thus the accompanying symptoms of herpes disease. Therefore, precisely regulated contact temperatures are important in the treatment of herpes. Precisely regulated contact temperatures in this range have also proven beneficial for the neutralization of insect venoms.
On the one hand, a temperature as high as possible should be selected for the application of heat, e.g. against herpes disease or itching. On the other hand, the associated pain can lead to premature discontinuation of the treatment impeding a treatment success.
That is why, for example, temperatures mentioned above may be preferred as contact temperatures for the treatment of herpes disease or itching.
For the purposes of the invention, the treatment surface preferably refers to a material surface of the device which is in direct thermal contact with the skin area during treatment.
The treatment surface may be a connected surface. It may also be preferred that the treatment surface consists of several non-connected partial surface. The size of the treatment surface preferably refers in each case to the total contact surface over which a skin area experiences a heat pulse. In the case of a treatment surface consisting of several partial surface, the size of the treatment surface preferably corresponds to the sum of the individual partial surfaces. Such a division into partial surfaces can be advantageous for certain manifestations of herpes, as well as for the treatment of certain parts of the body.
It is preferred that the treatment surface is brought to the desired contact temperature by means of at least one heating element. In a preferred embodiment, the treatment surface corresponds to the surface of a heating plate, which is heated with the aid of a heating element, wherein, for example, a semiconductor component can be used. However, the treatment surface may also denote a homogeneous material surface which is tempered by a plurality of heating elements. For example, it may be preferred to use two or four heating elements to guide the treatment surface particularly homogeneously and rapidly to the contact temperature. It may also be preferred to coat a heating plate comprising one heating element. In this case, the treatment surface is preferably understood as the coating of the heating plate, so that the contact temperature preferably indicates the temperature which is present on the side of the treatment surface facing the skin during contact of the treatment surface with the skin.
In terms of the invention, the control device is preferably a processor, processor chip, microprocessor, or microcontroller configured to regulate the temperature of the treatment surface using the at least one heating element according to predetermined contact temperature values.
Preferably, the heating element refers to the component which can be heated by the control device, inter alia, by applying an electric current. The at least one heating element is a component for which various embodiments are sufficiently known from the prior art. Thus, the heating element can comprise a power resistor, at which a well-defined temperature is generated in dependence of the current flow. Preferably, a field effect transistor (FET) can be used to quantitatively control the current flow through the heating element. However, it may also be preferred to use an FET itself as the heating element. In this case, energy dissipation in the transistor itself is used to generate heat and bring the treatment surface to the contact temperature. FETs are particularly preferred as heating elements because their small size allows small dimensioning. Furthermore, FETs are particularly reactive and ensure a particularly rapid response of the heating elements due to a very dynamic heat generation and heat dissipation.
Preferably, the control device may control which contact temperature is present by predetermining the current flow to the heating element. For example, a calibration can be used to determine the correlation between the current flow and/or voltage at the heating element with the contact temperature during contact of the treatment surface with the skin, so that a desired contact temperature can always be determined on the basis of the calibration.
However, it may also be preferred to regulate the contact temperature by the control device using a feedback loop. For example, it may be preferred to use a temperature sensor that measures a temperature at a position of the treatment surface, wherein the control device regulates the current supply to the heating element based on the temperature data. For this purpose, the control device may comprise, for example, a microprocessor.
For the purposes of the invention, a microprocessor is preferably understood to be a data processing device, i.e. a processor, which is characterized by small dimensions in the range of a few mm and where preferably all the components of the processor are on a microchip or integrated circuit (IC). The microprocessor can preferably also be a microcontroller which, in addition to the processor, integrates further peripheral elements on the microchip and, for example, also comprises a data memory.
It is also preferred that the microprocessor is installed on a printed circuit board (PCB). In addition to the microprocessor, the heating elements and the temperature sensors are preferably installed on the PCB. This preferred embodiment allows for an extremely compact and also robust design of the device and a particularly intelligent temperature regulation with the aid of the microprocessor. Thus, the microprocessor is not only able to evaluate the measured temperature data and translate it into a control of the heating elements, but can furthermore rapidly and reliably take into account additional parameters such as error messages and user input.
In a preferred embodiment of the invention, the device is characterized in that the microprocessor and the heating element and optionally a temperature sensor are installed on a printed circuit board (PCB), wherein at least the heating element and the temperature sensor are coated by means of a protective lacquer. In the sense of the invention, the protective lacquer is preferably understood as a lacquer or paint which is intended to protect components of the PCB from environmental influences.
For this purpose, the protective coating preferably is preferably electrically insulating and water-resistant. The electrical insulation property can preferably be quantified using the surface insulation resistance (SIR). The SIR can preferably be measured, for example, by leakage currents between the components of the printed circuit board. A high resistance corresponds to good electrical insulation. Water resistance preferably means that even in the presence of high humidity or water ingress, the coated electronic components remain intact and no short-circuiting occurs. Water resistance can also be tested, for example, by measuring the SIR under conditions of high atmospheric humidity.
Numerous protective lacquers preferentially suitable for use are known in the prior art. Examples include protective coatings based on acrylic, silicone or polyurethane. By applying the protective coating in the area of the heating elements and temperature sensors, these are effectively protected against deposits, such that incorrect measurements of the temperature sensors can be avoided. On the one hand, this increases the accuracy with which the contact temperature can be set and, on the other hand, prevents the treatment surface from overheating due to an incorrect temperature measurement.
Furthermore, the device comprises at least one contact sensor. In the sense of the invention, the contact sensor refers to a unit which, on the basis of measurement data and analysis thereof, can make a statement as to whether or not the treatment surface is in contact with a skin, for example a lip. Preferably, the contact sensor comprises for this purpose a sensor or a measuring unit which is connected to the control device, wherein the control device may process the measurement data.
By means of the contact sensor and an information on when the treatment surface contacts the skin, a particularly precise regulation of the heat flow for the treatment of herpes disease can be achieved. For example, the start of the heating phase can be made dependent on whether there is contact with the skin. The duration of the treatment phase can also be reliably recorded in order to monitor treatments that have been carried out and, if necessary, to adjust further applications accordingly. The contact sensor also allows improved control with regard to safety aspects. For example, a contact sensor can be used to prevent the treatment surface from heating up without the user's knowledge or intention.
By means of a contact sensor, for example, an accidental triggering of a heating process can be reliably avoided when carrying the device in a trouser pocket. The use of a contact sensor is particularly advantageous with regard to the flexible carrying of mobile devices for the treatment of itching or herpes. Thus, by using a contact sensor, on the one hand, a particularly energy-efficient operation is made possible, in which heating is triggered only in the case of an actual contact of the contact sensor on a skin. In addition, unintentional and dangerous heating, for example in a trouser pocket or next to sensitive devices, including smartphones with plastic parts, etc., is avoided.
Furthermore, it has been shown that a therapeutically effective temperature profile of the contact temperature can be achieved particularly precisely by means of a contact sensor. Thus, on the basis of the information from a contact sensor, a contact temperature of, for example, 43-47° C. can be precisely set within short heating phases of preferably 1 to 5 seconds, preferably less than 3 seconds, particularly preferably 1-2 seconds.
The information as to whether or not contact is established with the skin may be used efficiently in this regard to avoid a possible overshooting of the temperature of the treatment surface beyond the pre-set (predetermined) range. Instead, a focused hyperthermal treatment is carried out only after actual contact with the skin and preferably only during said contact. Temperature peaks, which may occur, when the device is briefly removed from the skin due to the omitted thermal load, can be effectively prevented.
For example, in known prior art devices without corresponding contact sensors, it can be observed that some subjects initiate heating simultaneously with applying the device or even somewhat prematurely. Since there is no thermal load on the treatment surface during this phase, the temperature can exceed the predetermined value. A painful sensation already at the start of treatment is the result. Similar undesirable effects can occur if the devices are removed from the skin for only a short time during treatment and then applied again.
Based on the information from a contact sensor, such overshooting can be effectively prevented. Particularly preferably, for example, a heating phase can be suppressed as long as the contact sensor does not confirm that a contact with the skin is established. If the treatment is already in progress, an immediate correction can be made on the basis of the information from the contact sensor in the event of a brief loss of contact. For this purpose, the control device can, for example, be configured in such a way that a higher heating power is provided in case of confirming a contact (and thus a thermal load) than in case of confirming no contact and thus a low thermal load.
The use of a contact sensor opens up a wide range of possibilities to ensure particularly targeted and precise control of the contact temperature or the entire temperature curve of the treatment device.
The use of a contact sensor is therefore of particular advantage for applications in which particularly precise control of the temperature curve is necessary for successful therapy. This applies, for example, to the treatment of cold sores (labial herpes). Herein, on the one hand, the highest possible contact temperature is necessary to reduce replication of the herpes viruses. On the other hand, the skin area is particularly sensitive, so that even if the normally tolerable range is slightly exceeded, the users will discontinue treatment.
Furthermore, also for other applications where a precise control of (a shortest possible) heating phase as well as a precise contact temperature during the treatment phase is desirable, the use of a contact sensor leads to significant advantages. This may concern, for example, applications with larger treatment surfaces of more than 1 cm², or even more than 3 cm², more than 5 cm²for example for large area treatment of pruritus. Improved treatment success can also be achieved for insect bites by precisely regulating the contact temperature and its temporal course.
Preferred contact temperatures may vary depending on the application.
In a preferred embodiment of the invention, the contact temperature is selected from a range of 43° C. and 56° C. Intermediate ranges from the above ranges may also be preferred, such as 43° C.-44° C., 45° C.-46° C., 46° C.-47° C., 47° C.-48° C., 48° C.-49° C., 49° C.-50° C., 50° C.-51° C., 51° C.-52° C., 52° C.-53° C., 53° C.-54° C., 54° C.-55° C., or even 55° C.-56° C. A skilled person will recognize that the aforementioned range limits can also be combined to obtain further preferred ranges, such as 43° C. to 46° C., 45° C. to 48° C., or even 43° C. to 47° C. Depending on the application, the aforementioned ranges may be particularly suitable for treating itching, for example, after insect bites.
In a preferred embodiment of the invention, the contact temperature is selected from a range of 43° C. and 47° C., preferably 44.5° C. and 46.5° , particularly preferably 45° C. and 46° C. The aforementioned ranges are particularly suitable for the treatment of herpes, in particular labial herpes.
Moreover, it may be particularly preferred to maintain the aforementioned contact temperatures for a treatment duration of 1 to 10 seconds, preferably 2 to 5 seconds, wherein it is particularly advantageous to ensure short heating phases of 1 second to 5 seconds, preferably less than 3 seconds and in particular 1 to 2 seconds. In a preferred embodiment of the invention, the device comprises at least one temperature sensor for measuring the temperature of the treatment surface, wherein the control device regulates the at least one heating element based on the measurement data of the temperature sensor.
In the sense of the invention, a temperature sensor is preferably an electrical or electronic component which generates an electrical signal depending on the temperature at the sensor. In the prior art, a variety of temperature sensors are known such as semiconductor temperature sensors, resistance temperature sensors, pyroelectric materials, thermocouples or oscillating crystals.
The control device is further preferably configured in such a way that it may receive and evaluate the measured values of the temperature sensors in order to effect regulation of the heating element(s). The regulation of the heating elements can preferably take place with the aid of the application of an electric current or a voltage. It is particularly preferred that the temperature sensor measures the temperature of the treatment surface directly, i.e. that the temperature sensor is in contact with the treatment surface, wherein the temperature sensor can be located on the inner side of the treatment surface as well as on the outer side of the treatment surface or may be integrated into the treatment surface.
The control device is configured to reliably set the contact temperature based on the measured temperature of the temperature sensor. For example, if the temperature sensor is positioned on the inner side of the treatment surface, the control device will be configured to set a higher temperature as a target temperature on the inner side of the treatment surface than is desired on the relevant outer side of the treatment surface during contact. The difference between such a target temperature and the contact temperature to be achieved can be provided to the control device on the basis of theoretical predictions about the heat flow within the treatment surface, when applied to a skin, or on the basis of calibration measurements as reference data.
However, it may also be preferred that the temperature sensor does not directly contact and monitor the treatment surface, but rather the heating elements or a material point between the heating elements and the treatment surface. In the case of multiple heating elements heating the treatment surface, for example, it may also be preferred to place the temperature sensor between the heating elements. The temperature of the treatment surface can also be inferred from the measurement data for the temperature across the heating elements or a measurement point at a certain distance from the treatment surface.
The contact temperature preferably refers to the average temperature of the outer side of the treatment surface while it contacts a skin during the application of the device.
An evaluation of the temperature of the treatment surface allows a particularly precise regulation of the at least one heating element to ensure an optimal temperature distribution on the outer side of the treatment surface and thus heat transfer to the skin areas to be treated. In particular with regard to the application of the device for sensitive skin areas, embodiments are characterized by a more targeted and controlled regulation.
In this embodiment of the invention, the device is characterized in that the control device can determine whether the treatment surface is in contact with the skin based on a correlation of the measurement data from the temperature sensor and data about the control of the heating element. In this embodiment, the contact sensor is formed by a temperature sensor and a control device for controlling the heating elements. The basis of the contact sensing is the knowledge that the current flow necessary to reach or maintain a temperature depends on whether the treatment surface is in contact with a thermal load (e.g., a skin). If the treatment surface heats up when it contacts the skin, there is a heat transfer which must be compensated by an increased energy supply to the heating elements. By evaluating the current and temperature curve, reliable statements can be made as to whether the treatment surface contacts a skin. Preferably, reference data can be provided to the control device for this purpose.
The embodiment is for example characterized in that, no separate optical or capacitive sensor is required to detect a contact. Instead, means that the device already comprises for temperature monitoring can be specifically adapted to detect a contact with the skin.
In addition, a particular advantage of this embodiment is that an actually desired contact with a skin can be distinguished very precisely from an accidental contact of the treatment surface with other materials (e.g. the inner fabric of a trouser pocket). Notably, the skin (like other materials) has a specific thermal fingerprint, which makes it possible to determine the presence of a contact with a skin particularly reliably by means of the configuration of a contact sensor described above.
It is also possible to detect a contact for specific skin areas based on such a contact determination. For example, the lip may impart a different thermal load than is the case for other skin areas. Depending on the presence of contact with a specific skin area, it is therefore possible to optimize or adjust the contact temperature within small limits.
In a preferred embodiment of the invention, the control device comprises reference data on a correlation of the temperature of the treatment surface with the control of the at least one heating element in case the treatment surface is in contact with the skin or with air. The reference data may comprise, for example, ratios of measured temperature and current supply required therefor. Particularly preferably, the reference data comprise such ratios for a temperature curve, so that the measurement of the current ratio of temperature and current supply can be used to determine particularly precisely whether the treatment surface contacts a skin. Advantageously, with the help of such a regulation, not only a contact with the skin compared to air, but also a contact with the skin compared to materials with other thermal properties can be reliably distinguished.
In another preferred embodiment, the reference data may include the average amount of heat transferred to the skin or to air. In this regard, the reference data may include correlations between contact temperature and transferred (emitted) heat. In preferred embodiments, reference data may also be recorded for different areas of the skin, for example the lip or the face, in order to either obtain a particularly meaningful average value or, as explained above, to optimize the course of treatment depending on the type of skin contact detected.
In another preferred embodiment of the invention, the device is characterized in that the treatment surface is made of a material having a thermal conductivity at 45° C. between 20 W/m K and 400 W/m K, preferably between 100 and 350 W/m K. The thermal conductivity (also referred to as thermal conductivity coefficient) preferably characterizes the thermal properties of the material from which the treatment surface is made. The thermal conductivity indicates the amount of heat that is conducted through the treatment surface when a temperature gradient is applied to it.
In addition to thermal conductivity, the heat transfer depends on the thickness of the treatment surface, the size of the treatment surface and the temperature difference between the inner side of the treatment surface (contact with the heating elements) and the outer side of the treatment surface (contact with the skin). Thermal conductivity is preferably expressed as the ratio of transported heat output watts (W) per temperature difference in Kelvin (K) and per meter (m). Since the thermal conductivity can also change slightly as a function of temperature, the reference temperature 45° C. is given here.
The thickness of the treatment surface further preferably indicates the preferred extension of the treatment surface between the outermost surface contacting the skin and the innermost surface contacting the heating elements. In some embodiments, the thickness of the treatment surface may be between 0.2 mm and 5 mm, preferably between 0.5 mm and 2 mm.
In a preferred embodiment, the treatment surface comprises ceramic or gold. It is particularly preferred that the treatment surface consists of gold or ceramic. On the one hand, the materials ceramic and gold fall within experimentally determined preferred ranges of thermal conductivity.
In addition, both ceramics and gold are surprising well suited for the treatment of herpes as well as itching. In particular, the materials lead an increased perceived pain masking in patients. This is surprising in that the effect may go beyond the mere temperature effect caused by thermally comparable materials.
In addition, gold and especially ceramics are characterized by a surprisingly high biological compatibility, which, coupled with a particularly low incidence of allergies to these materials, makes them particularly suitable for use in a device for the treatment of predominantly dermatological diseases.
A particularly preferred ceramic is aluminum nitride. To an especially large extent this is characterized by exceptional biological compatibility and excellent thermal properties. In addition, a treatment surface made of aluminum nitride is especially strongly electrically insulating, so that increased safety can be assured during use. This is particularly advantageous in conjunction with the use of a protective coating and leads to a synergistic increase in safety.
The advantage of using ceramics and in particular aluminum nitride is further apparent in that the treatment surface can be readily disinfected with a disinfectant without deterioration of the surface, thus achieving an antimicrobial effect with the above-mentioned advantages. Due to the increased safety when using protective lacquer in combination with a treatment surface made of ceramic and in particular aluminum nitride, liquid disinfectants can be used safely and without any problems.
However, disinfectants can also be used on a surface made of gold.
The use of disinfectants to disinfect a treatment surface or even the entire device is recommendable, especially for a device used to treat herpes disease, since herpes is known to be extremely contagious and a device can only be used by more than one person in case of a thorough disinfection.
In a preferred embodiment, the device is characterized in that the temperature sensor is present on the inner side of the treatment surface and the treatment surface is formed by a ceramic layer with a layer thickness between 50 μm and 2000 μm, preferably between 50 μm and 1500 μm and particularly preferably 50 μm and 1000 μm or also 50 μm and 500 μm. Intermediate regions from the above-mentioned ranges may also be preferred, such as 50 μm to 100 μm, 100 μm to 200 μm, 200 μm to 300 μm, 300 μm to 400 μm, 400 μm to 500 μm, 600 μm to 700 μm, 700 μm to 800 μm, 800 μm to 900 μm, 900 μm to 1000 μm, 1000 to 1100 μm, 1100 to 1200 μm, 1300 to 1400 μm, 1400 μm to 1500 μm, 1600 μm to 1700 μm, 1700 μm to 1800 μm, 1800 μm to 1900 μm or also 1900 μm to 2000 μm. A skilled person will recognize that the aforementioned range limits can also be combined to obtain other preferred ranges, such as 200 μm to 800 μm, 100 μm to 400 μm, or even 100 μm to 1000 μm.
In a preferred embodiment, the device is characterized in that the temperature sensor is present on the inner side or surface of the treatment surface and the treatment surface is formed by a gold layer with a layer thickness between 5 μm and 2000 μm, preferably between 50 μm and 1500 μm and in particular between 50 μm and 1000 μm or also between 50 μm and 500 μm. Intermediate regions from the above-mentioned ranges may also be preferred, such as 50 μm to 100 μm, 100 μm to 200 μm, 200 μm to 300 μm, 300 μm to 400 μm, 400 μm to 500 μm, 600 μm to 700 μm, 700 μm to 800 μm, 800 μm to 900 μm, 900 μm to 1000 μm, 1000 to 1100 μm, 1100 to 1200 μm, 1300 to 1400 μm, 1400 μm to 1500 μm, 1600 μm to 1700 μm, 1700 μm to 1800 μm, 1800 μm to 1900 μm, or even 1900 μm to 2000 μm, A skilled person will recognize that the aforementioned range limits can also be combined to obtain further preferred ranges, such as 200 μm to 800 μm, 100 μm to 400 μm, or even 100 μm to 1000 μm.
Due to the aforementioned preferred layer thicknesses, especially for the use of gold or ceramics, it is possible to adjust the contact temperature particularly precisely during use of the device and to maintain it within a narrow temperature range. It is possible to draw conclusions about the contact temperature on the basis of calibration curves or theoretical calculations, even for thicker treatment surfaces, starting from a temperature measurement on the inner side of the treatment surface. However, the above-mentioned layer thicknesses of preferably less than 2000 μm, less than 1500 μm and less than 1000 μm, in some cases less than 500 μm, minimize sources of error due to tolerances in manufacturing or changes in the device (moisture, wear, etc.) which can lead to altered heat fluxes in the treatment surface.
By implementing the temperature sensors on the inner side at a maximum of 1000 μm, preferably at a maximum of 500 μm, 200 μm or less below the outer side of the treatment surface, a more reliable measurement statement can be achieved on the contact temperature. In the context of a feedback regulation, the target temperature for the temperature sensor on the inner side will deviate only slightly from the targeted contact temperature, which means that possible interfering factors can be eliminated to a large extend.
The aforementioned thin treatment layers thus permit a particular precise regulation of the contact temperature to especially preferred values within small tolerances of less than 1° C., preferably less than 0.5° C., 0.4° C., 0.3° C., 0.2° C. or 0.1°. In addition, advantageously, the heating phase can be kept reliably within short preferred ranges of 1 second to 5 seconds, less than 3 seconds or 1 to 2 seconds by means of such thin layers of the treatment surface. Because of the thin layers, a delay due to the low thermal load is avoided. Also, reduced heating powers are necessary to set the desired contact temperature, so that the risk of overshooting, i.e. a brief rise to a contact temperature above the desired range, is avoided.
In a further preferred embodiment of the invention, the device is characterized in that the treatment surface is formed by a ceramic and the temperature sensor is integrated into the treatment surface. In this embodiment, the temperature sensor can advantageously be brought extremely close to the outer side facing the skin, irrespective of the thickness of the layer of the treatment surface.
The embodiment is therefore characterized by an additional degree of design freedom with regard to the layer thickness with equally precise regulation of the contact temperature. For example, it may be preferable to use a ceramic treatment surface with a layer thickness of 0.5 to 2 mm, wherein the temperature sensor is integrated as a thin-film sensor within the treatment surface. In contrast to known measuring methods in hyperthermal treatment, this allows for a particularly precise knowledge of the heat flow during treatment.
In another preferred embodiment, the contact sensor comprises an optical detector, a capacitive sensor, a tactile sensor, and/or a pyrometer.
For example, the contact sensor can comprise an optical sensor that transmits measurement data on the lighting conditions to the control unit. If the optical sensor is installed near or in the treatment surface, a drop in brightness indicates that the treatment surface is contacting a skin. However, it may also be preferred that a contact sensor designates a unit consisting of a temperature sensor and the control device for regulating the heating elements, whereby the contact sensor can draw conclusions about the presence of skin contact based on the correlation of current flow and actual temperature.
It is to be understood that contact sensors in the sense of the invention can only make probable statements about the contacting of a skin on the basis of measurable parameters which distinguish a skin in particular in contrast to air. This may concern, for example, thermal property skin as a thermal load, electrical properties of the skin such as its conductivity, and/or optical properties such as its opacity. The detection of a contact with the skin is in this sense is preferably to be understood as a measurement statement for a probable contact of a skin, in contrast to a condition where the treatment surface is at the air.
In a preferred embodiment of the invention, the device is characterized in that the contact sensor is an optical detector or comprises such a detector. In the sense of the invention, an optical detector preferably denotes a sensor for electromagnetic radiation, preferably in the visible range, i.e. in a wavelength range of 400-700 nm. An optical detector for the visible range is preferably also referred to as a light sensor. However, it may also be that the optical detector detects electromagnetic radiation in the infrared or ultraviolet range. Various optical detectors are suitable for the purposes of the device, such as photocells, photomultipliers, CMOS sensors, CCD sensors, photodiodes, phototransistors or photoresistors.
As a common feature these detectors can determine changes in the intensity of incident electromagnetic radiation and pass them on to the control device, usually in the form of an electrical signal. Preferably, the optical detector is present installed within the treatment surface or in the immediate vicinity of the treatment surface. Thus, when the device is used and the treatment surface is applied to a skin, the optical detector is at least partially, preferably entirely, covered by the skin area. This results in a change in the measured light intensity. Based on the measurement data on the change in light intensity, the control device can determine the presence of contact with the skin. For this purpose, the control device can also include reference data, for example on average light intensities in ambient light or on threshold values below which the optical detector is at least partially or completely covered.
The embodiment is characterized by a simple and yet reliable implementation of a contact sensor, which is furthermore associated with only low additional costs.
In another preferred embodiment of the invention, the device is characterized in that the contact sensor is or comprises a capacitive sensor. In the sense of the invention, a capacitive sensor preferably denotes a sensor which detects the change in the electrical capacitance of one or more capacitors. The capacitive sensor is preferably present installed within the treatment surface. As soon as the treatment surface contacts a human skin area or lip, the measured capacitance changes due to the coupling of the external capacitance. A capacitive sensor can thus reliably indicate the contacting of a skin area.
In a further preferred embodiment of the invention, the device is characterized in that the contact sensor is a tactile sensor or comprises such a sensor. A tactile sensor is preferably understood to refer to a sensor which may detect a contact with the treatment surface on a mechanical basis. The measuring principle is thus preferably based on the fact that when the treatment surface is placed on the skin, a pressure is imparted which can be detected mechanically by means of the tactile sensor. Various suitable tactile sensors are known to the person skilled in the art. As an example these can comprise range springs or piezoelectric elements which detect an indentation or displacement of the entire treatment surface.
In another preferred embodiment of the invention, the device is characterized in that the contact sensor is or comprises a pyrometer. In the sense of the invention, a pyrometer refers to a sensor for contactless temperature measurement. Preferably, the contactless temperature measurement is based on the measurement of thermal radiation, which is emitted by each body as a function of its temperature. The pyrometer can therefore also be referred to as a radiation thermometer or infrared sensor. The determination of the temperature of a body depends on its emissivity. The emissivity is the ratio of the radiated power emitted by an arbitrary body to the radiated power of a black body radiator of the same temperature. The emissivity depends on the material. Moreover, for certain materials, it may change with wavelength, temperature or other physical quantities.
In preferred embodiments, the pyrometer or infrared emitter is recessed into the treatment surface with an offset so that the temperature of objects located in front of the treatment surface or contacting the treatment surface may be measured. When a temperature is detected, which typically corresponds to the surface temperature on a skin, a contact of the skin can be determined on the basis of the measured data of the pyrometer. Suitable temperature ranges for this purpose are in particular about 28° C.-34° C., preferably about 30° C.-33° C. Suitable wavelength ranges for measuring these temperature ranges are in the mid-infrared range, preferably between 3 and 20 μm. The skilled person is familiar with various pyrometers which are suitable for the aforementioned purposes. In particular, the skilled person can furthermore make use of known technologies for contactless temperature measurements, which are employed in clinical thermometers.
In a preferred embodiment, the control device is configured such that the duration of the treatment phase is determined as a function of when a contact of the treatment surface with the skin is detected. By controlling the duration of the treatment phase as a function of a contact with the skin, a much more precise heat transfer can be achieved. For example, if heating has been started and contact with the skin is not detected until a later time, the treatment phase can be extended. This may ensure that the desired and therapeutically effective heat transfer takes place. Through such regulation, repeatable results may be achieved and deviating behavior in the use of the device can be effectively compensated for.
In another preferred embodiment of the invention, the device is characterized in that the control device is configured such that heating of the heating element is initialized only if a contact of the treatment surface with the skin is detected or that the control device is configured such that heating of the heating element is terminated as soon as it is detected that there is no contact of the treatment surface with the skin.
Such a control can prevent heating, for example, by accidental actuation of a switch during transport of the device. Unnecessary reheating, even though the user has already intentionally or unintentionally stopped the treatment, is also avoided. This saves energy and safeguards against improper use.
In another preferred embodiment, the device comprises a waterproof housing. The housing preferably provides an outer casing for the device such that it encloses, in particular, the control device and other electronic components. It is preferred that the housing comprises a housing head and a housing handle, wherein the treatment surface is preferably present at a lower portion of the housing head. For controlling and tempering the treatment surface, the housing preferably includes a cutout at the appropriate position. In the preferred embodiment, the housing is configured such that all cutouts, e.g. also any battery compartments that may be present, are watertight. For example, seals or suitable gaskets, possibly made of elastomers, may be used for this purpose. However, the skilled person is familiar with numerous other technical possibilities for designing a waterproof housing. The waterproof design of the housing represents an (additional) safety element, as it can effectively prevent damage to the control device or other electronic components due to infiltrating liquids. Also, the waterproof housing leads to the prevention of corrosion and thus to an extended useful life of the device. Especially in connection with the use of protective lacquer, safety can be increased synergistically. This is particularly important for disinfection processes of the device and especially of the treatment surface. Thus, the device can be thoroughly disinfected very easily and faultlessly by immersing the whole device in a disinfection liquid and keeping it there for a certain minimum time.
In further preferred embodiments, the device comprises additional safety elements that control the temperature of the treatment surface.
For one, the device may preferably include a hardware-implemented temperature monitor which limits the maximum temperature of the treatment surface to a value between 54° C. and 58° C., preferably about 56° C. The temperature of the treatment surface may also be limited to a value between 54° C. and 58° C. The hardware-implemented temperature monitor allows advantageously to ensure that a maximum temperature does not exceed a value between 54° C. and 58° C., preferably of approx. 56° C. The “hardware-implemented temperature monitor” preferentially refers to a temperature control system for the treatment surface, which can shut off the power supply of the heating elements for the treatment surface based on hardware. In particular, the “hardware-implemented temperature monitor” preferentially allows to cut the power supply to the heating elements when the maximum temperature is exceeded, independently of the regulation of the heating elements by the control device, e.g. the microprocessor. If, for example, a firmware is installed on the control device to regulate the heating elements, it is preferred that the hardware-implemented temperature monitor reliably limits the maximum temperature of the treatment surface, even in case of failure or incorrect performance of the firmware.
Other suitable maximum temperatures, e.g. between 43° C. and 47° C., may also be preferred.
In a preferred embodiment of the invention, the maximum temperature is selected from a range of 47° C. and 58° C. Intermediate ranges from the aforementioned ranges may also be preferred, such as 47° C.-48° C., 48° C.-49° C., 49° C.-50° C., 50° C.-51° C., 51° C.-52° C., 52° C.-53° C., 53° C.-54° C., 54° C.-55° C., 55° C.-56° C., 56° C.-57° C., or even 57° C.-58° C. A skilled person recognizes that the aforementioned range limits can also be combined to obtain further preferred ranges for the maximum temperature, such as 47° C. to 50° C., 50° C. to 54° C. or also 48° C. to 52° C.
Herein, simple means can be used to ensure that the treatment surface of the device does not exceed a maximum temperature. Even in the event of a failure in the control device, e.g. after an infiltration of liquids, the hardware-based temperature monitor can advantageously ensure at all times that the treatment surface does not exceed a maximum temperature of between 47° C. and 58° C., preferably 54° C. and 58° C., preferably approximately 56° C. This additional technical element for a temperature monitoring makes it possible to maintain an excellent safety standard without interfering with the operation of the hyperthermal treatment device.
Since a contact sensor can effectively prevent thermal overshooting in a functioning control device. It is further possible to use maximum values for the hardware-implemented temperature monitor that are particularly low or particularly close to the desired treatment range.
In the case of a desired contact temperature from 43° C. to 47° C., for example, it may be preferable to specify a maximum temperature between 48° C. and 54° C., preferably between 50° C. and 54° C. Without a contact sensor, the temperature ranges can be briefly reached in the event of a loss of contact or the associated loss of a thermal load. As described above, a contact sensor can be used to prevent such overshooting. Conversely, this means that when using a contact sensor, exceeding the desired temperature range already indicates with a high probability a malfunction of the firmware, which justifies intervention by the temperature monitor.
As an additional safety element, the device may comprise a safety fuse which, in the case of a short-circuit in the device or uncontrolled continuous heating of the device, interrupts the power supply to the device. In the meaning according to the invention, a safety fuse preferably defined as an excessive current protective mechanism in which an electrical circuit can be interrupted, for example by the melting of a fuse element as soon as the strength of the current exceeds a limiting value for a time to be determined. It is preferred for the safety fuse to be located in the device between the input of the supply voltage into the device and the device itself. If a malfunction should occur that is characterize by the flow of an uncontrolled high current from the supply voltage feed into the device, the safety fuse will advantageously shut down the power supply to the device completely. A safety fuse offers sufficiently fast, and on the other hand, extremely reliable protection.
It has been found that even with faultless design of the device and the supplying of a hardware-implemented temperature monitor it is not possible to rule out the occurrence of continuous heating of the heating elements in extremely rare instances because of incorrect operation. Continuous heating of the heating elements in the meaning of the invention preferably means that the temperature of the heating element rises uncontrolled, i.e., without temperature-based regulation with the aid of the control device. If during such breakdowns the hardware-implemented temperature monitor fails, the treatment surface can rise uncontrollably to temperatures far above the desired contact temperature, for example to temperatures far in excess of 65° C.
Although such undesirable continuous heating occurs extremely rarely, it can cause severe injuries to the subjects. This is especially due to the fact that the skin parts to be treated with hyperthermia, such as lips, are usually particularly sensitive and, for example, are characterized by redness, swelling or even wound formation. A temperature distinctly elevated above 65° can lead to severe local pain at these sites and can cause burns to the skin.
The safety fuse described is especially advantageous for being able to guarantee that the heating of the treatment surface will be switched off even in the most unlikely instance of a malfunction. For example with the aid of the safety fuse, independently of any temperature measurement, excessive heating of the treatment surface, due for example to defective temperature sensors, can be suppressed. It was recognized that the power supply to the device represents a central regulatory interface that meets the highest safety requirements. By integration of the safety fuse into the current flow for supplying the device it is possible to ensure that a maximum supply current will not be exceeded for a certain time. Since continuous heating and uncontrolled heating of the heating elements above the desired temperature are related to increased current flow, in this way overheating of the treatment surface can be avoided especially reliably. In particular, the current controller can react very quickly before the current is present for long enough that it will produce a temperature corresponding to its strength.
The combined use of a hardware-implemented temperature monitor and a fuse is particularly advantageous.
For example, one drawback of the safety fuse is that following the single triggering it permanently disconnects the supply voltage from the device. Resumption of the use of the device following triggering of the safety fuse requires repair by a technician, for example replacement of the safety fuse. In terms of cost, the device has generally become unusable when the fuse has been triggered.
Advantageously, however, the hardware-implemented temperature monitor is set such that it does not need to cause permanent shutoff of the power supply to the device. Instead, the hardware-implemented temperature monitor is designed in such a way that if the temperature of the treatment surface exceeds a maximum temperature, the power supply to the heating elements is interrupted during the time period exceedance. Thus the current interruption by the hardware-implemented temperature monitor is advantageously reversible, i.e., as soon as the temperature of the treatment surface again drops below the maximum temperature, the heating elements can heat again.
Thus even after a one-time occurrence of a malfunction the normal use of the device can be continued. The user would also not notice the malfunction, since as a result of the maximum temperature selection, the effectiveness and the independence of the temperature controller, no temperatures perceived by the user as unpleasant will develop and once a malfunction has occurred, the device can function perfectly again upon the next use.
The combination of the safety features of a hardware-implemented temperature monitor with a safety fuse allows for surprisingly reliable control of the temperature by the most economical means possible because of the hierarchy of safety barriers.
In a preferred embodiment of the invention, the hardware-implemented temperature monitor comprises at least a second temperature sensor for measuring the temperature of the treatment surface and a comparator, wherein the comparator compares the temperature of the treatment surface with the maximum temperature and, if the maximum temperature is exceeded, stops the current feed to the at least one heating element. In the sense of the invention, a comparator preferentially refers to an electronic circuit for comparing two voltages, whereby the output indicates in binary form which of the two voltages is higher. In the prior art, various comparators are sufficiently well known, which are suitable for using two analog voltages to output one binary output signal and indicating which of the input voltages is higher. The Schmitt trigger may be mentioned as an example of a comparator circuit. It is preferred for a reference value for a voltage be applied to one input of the comparator using a voltage splitter. This reference value preferably corresponds to the voltage value that the second temperature sensor would show if the temperature of the treatment surface is equal to the maximum temperature. At the second input of the comparator, the output voltage of the temperature sensor, which depends on the temperature of the treatment surface, is preferably present. A particularly preferred temperature sensor has an NTC thermistor, i.e., a thermal resistor. This has a negative temperature coefficient, so that when the temperature increases, the resistance decreases and a higher current flows. However, posistors, i.e., PTC thermistors, having a positive temperature coefficient, may also be used, so that when the temperature increases, the resistance increases and a lower current flows.
If the temperature of the treatment surface increases, the voltage value at the comparator, regulated by the second temperature sensor, moves toward the voltage reference value that corresponds to the maximum temperature. As soon as the temperature exceeds the maximum temperature, the output signal on the comparator changes in a binary manner. The comparator is preferably integrated in the power supply of the heating elements. In other words, before the temperature of the treatment surface reaches the maximum temperature, the comparator preferably unblocks the supply voltage of the heating elements. However, as soon as the temperature is higher than the maximum temperature, the outlet of the comparator shuts off and interrupts the power supply to the heating elements. When the temperature of the treatment surface drops again, supply voltage is advantageously unblocked again by the comparator. As a result, reversible on and off switching of the heating elements can only take place for the time period during which the temperature of the treatment surface exceeds the maximum temperature. In addition, it may be preferred for the comparator to be unlocked by the control device when the device is turned on. Thus if correct start-up of the device does not take place, the comparator is configured in the setup phase such that the current feed of the heating elements is interrupted.
The preferred embodiment of the hardware-implemented temperature monitor described has proven in tests to be especially robust and reliable. Because of the reversibility of the safety switch and the simple design, the preferred embodiment is also characterized by low manufacturing and maintenance costs.
Due to the design independent of the control device and to the dedicated temperature sensor, reliable operation can be guaranteed even in the case of failure of a component of the control device.
In addition, a hardware-implemented temperature monitor in the described form using a comparator is especially rapid, since comparators are widely used electronic components which are distinguished by their reliability as well as their rapid switching capacity. Thus, for example, comparators with switching times of nanoseconds or less are available.
In a preferred embodiment of the invention, the device is characterized in that the safety fuse has a threshold value for a maximum current which corresponds to the heating of the treatment surface to a value of between 65° C. and 70° C., preferably of 65° C. for 1 second.
Tests have shown that only a temperature increase to above 65° C. for more than 1 second is highly critical for the pain sensation and can cause damage to skin parts. Advantageously, by setting the safety fuse for these parameter values, the safety fuse will not be triggered prematurely in the case of noncritical temperature elevations of the treatment surface. In this way it is possible to increase the economic efficiency without compromising on safety. The person skilled in the art knows, based on the electrical parameters of the heating elements, which safety fuse should be selected to guarantee the indicated values. For this purpose, the current flow may be measured while simultaneously measuring the temperature of the treatment surface. In addition it is particularly preferred to use a fast-acting safety fuse, which preferably reacts to a current increase within less than 20 ms. Thus it was recognized that even a short-term increase in the current for less than 20 ms can lead to a temperature elevation for more than 1 second because of the thermal inertia of the treatment surface.
Compared with non-resettable, purely temperature-dependent thermal fuses, which likewise function by melting, the current-dependent safety fuse used here has several advantages. In the case of non-resettable, purely temperature-dependent thermal fuses, the melting does not take place upon application of a current above a threshold value, but only upon application of an external temperature that is higher than a defined maximum temperature. Thus in contrast to non-resettable, purely temperature-dependent thermal fuses, current-dependent safety fuses can react even before a certain undesirable temperature is reached as a result of an elevated current acting for a relatively long period. Likewise, non-resettable, purely temperature-dependent thermal fuses always require a certain reaction time in the presence of an external temperature above a defined maximum temperature. In this way, dangerous further temperature elevations can occur. In contrast to this, current-dependent safety fuses react more quickly and with minimal system-related latency times.
In a preferred embodiment of the invention, the device is characterized in that the threshold value of the safety fuse is preferably between 1 A and 2.5 A, particularly preferably approximately 2 A. Tests have shown that with regard to the preferred heating elements, the threshold values mentioned guarantee with especially good reliability that the temperature of the treatment surface will exceed a temperature of 65° C. to 70° C. for no more than 1 second. Thus, it is possible to ensure by the melting of the safety fuse above 1 A to 2.5 A that the temperature of the treatment surface cannot enter a range that is hazardous to health. Thus in the case of a normal treatment, a normal treatment current that is less than 2.5 A, preferably 1 A occurs. If a malfunction occurs, e.g., in case of continuous heating, an increased current will flow. In this case, the fuse intervenes and effectively prevents uncontrolled heating.
It may also be preferable to use only one of the safety elements selected from hardware-implemented temperature monitors and/or safety fuses. In this way, a particularly simple structure can be implemented, whereby an acceptable level of safety is achieved.
In a preferred embodiment of the invention, the contact temperature is between 43° C. and 56° C. In this way, various conditions can be treated individually. It has been recognized that an especially strong masking of the itching sensation can be achieved if the thermo- and capsaicin receptors TRPV1 and TRPV2 are activated locally in the affected skin areas at the same time. TRPV1 is involved in acute heat-induced pain in healthy skin and regulates, for example, heat sensation at temperatures around 45° to 50° C. In the case of a particularly strong painful heat stimuli, which occurs at temperatures above 52° C., TRPV2 is also activated. The activation threshold of TRPV1 is between 40° C. and 45° C., whereas that of TRPV2 is between 50° C. and 53° (Yao et al 2011, Somogyi et al 2015, Cohen et al 2014, Mergler et al 2014). While an initial understanding of the mode of action of TRPV1 and TRPV2 receptors as temperature sensors is emerging through recent research in the literature, their role in itch sensation is unknown. Therefore, even with knowledge of the literature, a person skilled in the art would not assume that it is the activation of these receptors that provides a particularly effective masking of itch sensation.
In a preferred embodiment of the invention, the contact temperature is 43° C.-47° C., wherein the control device is configured to maintain the contact temperature for a period of time between 1 to 10 seconds.
Due to the precise regulation of the contact temperature in a range of 43° C.-47° C. for the treatment phase of 1 s-10 s according to the invention, excellent results were achieved in terms of a decrease in itching and/or herpes blisters within a short time, without complaints of stinging pain. Compliance and therapeutic success were consistently good for the device according to the invention.
Excellent results were achieved with a preferred embodiment of the device, in which the contact temperature is between 44.5° C.-46.5° C., particularly preferably between 45° C.-46° C. For the aforementioned temperature ranges, studies showed in some cases a visible and/or perceptible abatement of itching and/or herpes blisters and redness within 2 days, in some cases within one day. This indicates that the aforementioned ranges represent an optimal treatment regime. The high therapeutic success of the treatment regime can only be partially explained, for example, by the thermolability of the DNA-binding protein of the herpes virus. At the same time, for the temperature ranges of 44.5° C.-46.5° C., especially 45° C.-46° C., the body's own immune system seems to be supported, so that with regard to the treatment success for the narrow temperature range, a synergistic effect is responsible, which includes an inhibition of the replication of the herpes viruses and/or a thermal neutralization of the toxins, e.g. of insects, with simultaneous activation or support of the body's own immune system.
In addition, subjects reported significantly reduced itching for the preferred contact temperatures of 44.5° C.-46.5° C., in particular between 45° C.-46° C. Surprisingly, the reduction in itching persisted for hours after treatment. As a secondary treatment effect, a reduced scratching of herpes blisters was recorded in the treatment of herpes, which additionally contributes to faster healing.
This was especially true for the combination of the aforementioned temperatures with a treatment time of 2 to 5 seconds.
In a preferred embodiment of the invention, the heating phase is 1 second to 5 seconds, preferably less than 3 seconds and in particular 1 to 2 seconds. Such a rapid heating phase allows the desired temperature to be reached particular rapidly. Thus, healing effects can preferably be achieved without unnecessarily supplying heat to a user and/or increasing the time effectively required for a treatment. In addition, the amount of heat emitted during the treatment can be determined with a particular high precision.
Due to the targeted and significantly faster heating phase compared to known devices of the state of the art, a particularly high acceptance of the test persons and thus a reliable therapy success can be achieved. Advantageously, it is avoided that the skin areas of the subjects are unnecessarily irritated during a therapeutically ineffective heating phase. Instead, the therapeutically effective contact temperature for herpes treatment, for example a value between 43° C.-47° C., is reached rapidly and reliably.
The heating phase preferably indicates the duration during which the outer surface of the treatment surface is brought to a contact temperature, for example 43° C.-47° C., by heating at least one heating element. Due to the low thermal load of a treatment surface, an initial temperature of the treatment surface corresponding to a typical skin surface temperature (e.g. 32° C.) is usually reached relatively rapidly when the device is applied to a skin area. The heating phase therefore preferably indicates the duration of the temperature rise from a natural body skin temperature to the desired contact temperature during the treatment phase of a value between 43° C. and 47° C., for example.
In a particularly preferred embodiment of the invention, the size of the treatment surface is between 30 mm²and 50 mm². Particularly in the case of herpes diseases, especially in the mouth (so-called herpes labialis), the preferred size of the treatment surface is ideal to cover all possible affected areas. In particular, a treatment surface between 30 mm²and 50 mm²is suitable to cover all typical affected skin areas with only one application of the device. However, this size may also be particularly suitable for treating insect bites, such as those of mosquitoes or ants. Furthermore, a device having such a treatment surface can be kept particularly compact. Thus, device sizes corresponding to that of a lipstick can be achieved. Such a compact device is readily and willingly carried permanently on the body or in a pocket carried along, so that treatment may be carried out at any time. This significantly increases the success of the treatment. The treatment surface is preferably round, which is particularly suitable for treating herpes, wherein the affected skin areas often exhibit nearly round shape.
It is also possible to use arbitrary three-dimensional shapes, especially convex shapes, which are particularly suitable for the treatment of herpes. For example, the shape of a lipstick can be used encouraging the user is to gently press on the device during treatment. Hereby, a psychological effect can be triggered that enhances a sense of well-being during treatment. Also, the amount of heat transferred can be improved. An organic form may be used, which is particularly suitable for treating the lips in particular.
In addition, it has been shown that a combination of the size of the treatment surface together with the preferred contact temperatures and treatment phase is particularly effective for example for treating herpes, especially on lip areas. On the one hand, the treatment surface is large enough to effectively cover adjacent areas and thus treat the border area of infected skin areas. On the other hand, the maximum size of the treatment surface is perceived as particularly pleasant without any painful sensations, despite the hyperthermal treatment. This is of particular significance in sensitive area of the mouth, especially the lips. For subjects with the aforementioned parameters, both the best compliance values, i.e. the highest willingness of the patients to actively participate and use the device, and the best therapy successes are observed.
In a preferred embodiment of the invention, the size of the treatment surface is less than 1 cm², preferably between 20 mm²and 80 mm².
These sizes of treatment surfaces have proven to be particularly beneficial for treating itching after an insect bite.
For the treatment of insect bites, especially mosquito bites, the size of the treatment surface is preferably between 10 mm²and 100 mm², particularly preferably between 20 mm²and 60 mm². These sizes are suitable for a targeted treatment of the entire affected area without unnecessarily heating unaffected areas of the skin.
In addition, such device sizes are particularly compact and may correspond to the size of a lipstick. Such a compact device is often and gladly worn permanently on the body or in a bag carried along, so that treatment can be carried out at any time. This significantly increases the success of the treatment.
In a further preferred embodiment of the invention, the size of the treatment surface is at least 4 cm², at least 6 cm2 preferably at least 7 cm², particularly preferably between 6 cm²and 18 cm², especially preferably between 6 cm²and 9 cm²or also between 7 cm²and 10 cm². Hereby itching can be reduced to a particularly high degree, especially on large areas of skin.
For example, in the case of skin rashes, it is possible to convert the itching sensation into a tolerable pain sensation by simply and comfortably placing the treatment surface on the corresponding skin areas. Secondary damage to the skin, for example the formation of wounds due to intense scratching, can be effectively avoided. Particularly in the case of large treatment surfaces, the use of a contact sensor according to the invention can be advantageous. The contact sensor, as described, not only allows precise and reliable control of the contact temperature curve, but moreover ensures a higher degree of safety and more efficient use of energy.
In further preferred embodiment of the invention, the device is characterized in that the device comprises a power supply unit and a voltage monitor which monitors the voltage of the power supply unit. In the sense of the invention, the power supply unit preferably provides the electrical energy to operate the device. Preferred power supply units are regular batteries or rechargeable batteries. These usually supply the electrical energy by providing a DC voltage. In the preferred embodiment, the voltage provided by the power supply unit is monitored by a voltage monitor. In the sense of the invention, a voltage monitor preferentially refers to an electrical circuit that can measure the voltage of the power supply unit and triggers an action if it falls below a predetermined limit value. In the prior art a number of variants for voltage monitors are known, wherein the person skilled in the art knows which voltage monitor is suitable for which types of power supply units, i.e. in particular batteries or rechargeable batteries. It is preferred that if the voltage monitor detects a drop in the voltage of the power supply unit below a certain value, it transmits an interrupt request (IRQ) to the control device, which is preferably a microprocessor. If a treatment cycle, i.e. a heating phase or treatment phase, is in operation during this time, the interrupt request causes the treatment cycle to be aborted. This represents a further safety mechanism. It was recognized that an insufficient voltage at the power supply unit can cause failure of the control device, e.g. the microprocessor. In this case it may occur that the temperature regulation of the contact temperature by means of the control device is carried out incorrectly and uncontrolled heating of the treatment surface occurs. The voltage monitor may additionally contribute to increasing the safety of the device and to avoiding a health hazard in the event of a defective battery, for example.
In a preferred embodiment of the invention, the device is characterized in that the device comprises a data memory for storing the system data and/or error messages. Preferred system data includes a treatment cycle counter, which preferably count the use of different types of treatment cycles separately. For example, if a shorter or a longer treatment cycle can be selected, this will be counted separately. Furthermore, the system data preferably comprises a boot counter, i.e. a counter for how often the device was started up, as well as information on the error messages with a current error status.
Preferably the following error messages can be stored: “Reset” indicates that the voltage monitor has triggered a reset. “Watchdog” indicates that a watchdog reset has occurred in the firmware, i.e. a system restart due to a software error. It is further preferred that for an error reporting the program mode is determined in which the apparatus was operating when the error occurred. “Temperature too high” may indicate that the temperature measured at the temperature sensor is too high or that the temperature sensor is defective. A “temperature too low” may indicate that the temperature measured at the temperature sensor is too low or that the temperature sensor is defective. “Contact temperature reached” may indicate whether the desired contact temperature has been reached or an error has occurred during the preheating phase.
Advantageously, the stored system data and error messages can be used for diagnosis and troubleshooting of the device. For example, these data can be read out when a customer sends in a defective device. Based on the data it is possible to correlate the error that occurred, e.g. “Temperature too high”, with further system data on the number of treatment cycles or watchdog resets. Based on these data therefore it is possible to continuously optimize the safety features of the device during the development phase and afterwards. The ability of the device to store system data and error messages allows continuous improvement of the hardware and software components of the device based on meaningful data.
In a further preferred embodiment, the device is characterized in that firmware is installed on the control device which at least controls the temperature regulation of the treatment surface, wherein the firmware comprises a watchdog counter (WDC) that monitors whether the firmware is executed. In the sense of the invention, firmware is preferably understood as software, i.e. the instructions for a computer-implemented process, which is embedded in the control device, preferably in the microprocessor. In other words, the firmware preferably comprises the software that is functionally linked with the hardware of the device, i.e., especially with the heating elements and temperature sensors. Preferably, the firmware is executed when the device is started and takes over the monitoring and control function of these hardware components of the device. Thus, the control device evaluates the measured data of the temperature sensors as well as user inputs preferably on the basis of the firmware in order to control the power supply for the heating elements during the treatment cycle. In the sense of the invention, hardware-implemented components are preferably components, the function of which is assured independently of correct execution of the firmware. As described above, the temperature monitor is hardware-implemented so that its function, i.e. a limitation of the maximum temperature, can take place independently of a correct execution of the firmware on the control device. Even in the event of a system failure of the firmware, the hardware-implemented temperature monitor therefore can quickly and correctly limit the maximum temperature of the treatment surface.
In the particularly preferred embodiment, the firmware of the control device is monitored with the aid of a hardware-implemented watchdog counter. Especially preferred is a time-out watchdog. The time-out watchdog is preferably activated by the firmware before the start of the treatment phase. During the treatment phase, the firmware will send a signal to the time-out-watchdog within a predetermined time interval to reset it. If the time-out watchdog is not reset, this will preferably lead to restarting the firmware. The time interval is preferably based on the time projected for carrying out a temperature measurement and regulation of the heating elements by the firmware and can, for example, amount to between 2 ms and 10 ms. Such a time-out watchdog can advantageously ensure that at least during the treatment phase of the device the firmware functions correctly and the temperature of the treatment surface is monitored. By using a hardware-implemented watchdog for monitoring the firmware, preferably for example with the aid of a time-out watchdog, it is thus possible to make sure that if the firmware does not function correctly and the predetermined time interval is not maintained, the treatment phase will be interrupted. Thus, a further safety feature of the device is available in addition to those mentioned above, which, especially in combination with the hardware-implemented temperature monitor, ensures that overheating of the treatment surface is ruled out even if the firmware is not functioning correctly.

Claims

1. A device for the treatment of itching and/or herpes disease on a skin, comprising

a) at least one treatment surface and

b) a control device for regulating the temperature of the treatment surface,

characterized in that

the control device is configured to regulate the treatment surface on an outer side facing the skin by heating at least one heating element in a heating phase to a contact temperature during a contact of the treatment surface with the skin and to maintain the contact temperature in a treatment phase and wherein the device comprises at least one contact sensor.

2. Device according to any one of the preceding claims

characterized in that

the contact sensor is realized by at least one temperature sensor for measuring the temperature of the treatment surface during the contact with the skin and the control device, which regulates the at least one heating element based on the measurement data of the temperature sensor, wherein the control device can determine whether the treatment surface is in contact with the skin based on a correlation of the measurement data of the temperature sensor and data about the control of the heating element.

3. Device according to the preceding claim

characterized in that

the control device comprises reference data on a correlation of the temperature of the treatment surface with the control of the heating element in case the treatment surface is in contact with the skin or with air.

4. Device according to any of the preceding claims 2-3

characterized in that

the temperature sensor is present on the inner side of the treatment surface and the treatment surface is formed by a ceramic layer with a layer thickness between 50 μm and 2000 μm and/or the temperature sensor is present on the inner side of the treatment surface and the treatment surface is formed by a gold layer with a layer thickness between 50 μm and 2000 μm.

5. Device according to any of the preceding claims 2-4

characterized in that

the treatment surface is formed by a ceramic layer and the temperature sensor is integrated into treatment surface.

6. Device according to any one of the preceding claims

characterized in that

the contact sensor comprises an optical detector, a capacitive sensor, a tactile sensor and/or a pyrometer.

7. Device according to any one of the preceding claims

characterized in that

the control device is configured in such a way that the period of the treatment phase is determined as a function of when a contact of the treatment surface with the skin is detected.

8. Device according to any one of the preceding claims

characterized in that

the control device is configured in such a way that heating of the heating element is only initialized, if contact of the treatment surface with the skin is detected or the control device is configured in such a way that heating of the heating element is interrupted as soon as it is detected that there is no contact of the treatment surface with the skin.

9. Device according to any one of the preceding claims

characterized in that

the device includes a waterproof housing.

10. Device according to any one of the preceding claims,

characterized in that

a hardware-implemented temperature monitor limits a maximum temperature of the treatment surface to a value between 54° C. and 58° C., preferably about 56° C., and/or a safety fuse switches off the device in the event of a short circuit or uncontrolled heating.

11. Device according to any one of the preceding claims

characterized in that

the contact temperature is between 43° C. and 56° C.

12. Device according to any one of the preceding claims,

characterized in that

the contact temperature is between 43° C. and 47° C. and the control device is configured to maintain the contact temperature for a period between 1 to 10 seconds.

13. Device according to any one of the preceding claims

characterized in that

the contact temperature is between 44.5° C.-46.5° C., preferably between 45° C.-46° C., and the control device is configured to maintain the contact temperature for a period between 2 to 5 seconds.

14. Device according to any one of the preceding claims

characterized in that

the heating phase is 1 second to 5 seconds, preferably less than 3 seconds, in particular 1 to 2 seconds.

15. Device according to any one of the preceding claims

characterized in that

a size of the treatment surface is between 30 mm²and 50 mm²or between 6 cm²and 18 cm².