EP1638464A1

EP1638464A1 - Device and method for determining an allowed exposure of human skin to uv radiation

Info

Publication number: EP1638464A1
Application number: EP04738837A
Authority: EP
Inventors: Markus Hahl
Original assignee: Manfred Holtkamp Elektro and Elektronik Gerate and Co GmbH
Current assignee: Manfred Holtkamp Elektro and Elektronik Gerate and Co GmbH
Priority date: 2003-07-02
Filing date: 2004-07-01
Publication date: 2006-03-29
Also published as: US20060151709A1; DE202004021309U1; CA2530875A1; DE112004001616D2; WO2005002437A1; DE10329915A1

Abstract

The aim of the invention is to be able to produce verifiable and reproducible information regarding the maximum radiation dose and/or the maximum exposure time of a subject to a UV radiation source. Said aim is achieved by a device for determining the allowed exposure time and/or radiation dose, comprising a UV emitter (7) for emitting a UV radiation, a UV sensor (8) for receiving the UV radiation reflected in and/or on the skin, and an evaluation unit for determining the radiation absorption. Particularly such a device individually measures the absorption of the erythema-effective UV radiation in a layer of a subject's skin, which is subject to hyperkeratosis, a UV radiation threshold value being assigned.

Description

Device and method for determining the permissible irradiation of human skin with UV radiation

Description:

The invention relates to measuring devices and a method for determining the permissible radiation duration and / or radiation dose of the human skin with UV radiation, in particular with regard to the use of sun beds in tanning salons, but also for the preparation, for example, of a vacation in a high mountain region southern countries and the like.

Many people are not aware that the skin can often suffer serious, irreversible damage on a long weekend or on a single day of excessive sun exposure. In particular, people with pale winter skin are also at high risk in Central European summer.

In order to prevent damage to the skin, for example in the form of a sunburn, it is often recommended to visit a tanning salon before a vacation or a trip and to accustom the skin to such radiation by irradiating it on a sunbed with, in particular, light with a high UV radiation component , whereby the skin develops natural protection against UV radiation through tanning.

In addition to this protective function, many people also find tanning to be aesthetic, which is why they go to tanning salons for no compelling reason. The UV radiation from the sun or a tanning bed responsible for tanning usually uses UV-A radiation with a wavelength of 315 (320) -380 (400) nm, UV-B radiation with a wavelength of 280-315 (320 ) nm and UV-C radiation with a wavelength of 100-280 nm.

The UV-A radiation darkens existing, undyed melanin precursors, dopamines, stimulates the repair of ultraviolet-induced nucleic acid damage, light repair, and initiates light recovery, photorecovery. On the other hand, however, the biological harmful effects of UV-B radiation are intensified.

UV-A radiation, which is often differentiated into UV-AI radiation with a wavelength between 340 nm and 400 nm and UV-A2 radiation with a wavelength between 315 nm and 340 nm, is for chronic damage to the skin connective tissue responsible, for example an elastosis or so-called aging skin with increased wrinkling. In addition, UV-A radiation leads to photodermatoses and photodynamic reactions due to interactions with pathological metabolic products and certain pharmaceuticals.

The short-wave portion of UV-A2 radiation contributes to the acute and chronic harmful effects. The longer-wave portion of UV-AI radiation, on the other hand, causes hardly any damage to the nucleic acid or the skin connective tissue. For cosmetic tanning, not only should UV-B radiation be administered in extremely well-dosed form, but the UV-A2 radiation component should also be labeled in order to indicate the danger of a radiator. UV-B radiation causes sunburn, promotes pigment binding and leads to the formation of light swellings, a natural defense mechanism of the skin against UV radiation. However, UV-B radiation in an uncontrolled and excessive dose leads to chronic light damage to the epidermis up to sun carcinomas. From a dermatological and medical point of view, the medium-wave ultraviolet radiation UV-B is therefore problematic for various reasons.

First, it causes sunburn if the erythema threshold, which triggers reddening of the skin, is exceeded. Furthermore, repeated overloading of the skin with UV-B radiation leads to chronic light damage such as one, even without sunburn

Early skin care, embossed cancer or even skin cancer. Chronic light damage is already certain when 60% of the erythema threshold is reached. The lowest UV-B dose that just leads to reddening, the erythema threshold, differs individually. In addition to a strong dependency on the type of pigmentation, the degree of built-up calluses, the skin's natural defense against UV radiation, is also crucial.

The UV-C radiation is of no decisive importance here

Significance, since known UV radiation sources, such as those used in tanning salons or the like, do not have such a radiation component.

The individuality of the skin's natural defense against UV radiation is the reason for the difficulties in determining the maximum radiation dose and / or the maximum radiation duration of a subject, in which negative health effects can be safely excluded. Exclusively stand for the determination of these maximum values phenomenological criteria are available, the so-called photo or skin type determination, in which a classification based on a visual assessment of the test person according to the color of the eyes, the hair, the number of freckles, the color of the natural complexion and the nipples as well as the skin reaction in the sun in four, sometimes in five photo types, which classification is then used as a measure of an allowable upper limit of threshold radiation. For example, to determine the maximum radiation duration, the erythema-effective threshold radiation of 250 J / m ² for phototype II, 350 J / m ² for phototype III and 450 J / m ² for phototype IV is largely arbitrarily determined. In addition to a non-verifiable classification into just four or five photo types, the natural, individual light calluses are also completely disregarded.

In addition to this essentially arbitrary division of the test subjects into photo types and a resulting recommendation for the max. UV radiation dose and the max.

Irradiation time, the physical properties of the UV lamp, regardless of whether it is the sun or a tanning bed or the like, are of crucial importance for determining a measure for the maximum irradiation time or a threshold dose. So the natural UV radiation depends on the location, the time of day, the cloud cover and the like.

Based on the division into phototypes, permissible radiation doses of UV radiation devices are only through

Guidelines, for example the FDA (Food and Drug Administration) in the USA or the EU Commission in Europe. In Germany, for example, the Radiation Protection Commission further stipulates that artificial UV lamps should be operated and operated by specialist personnel monitored devices must not exceed an erythema-effective irradiance Eer of 0.3 W / m ^{2 in} accordance with a sun erythema factor of 1. Likewise, the total irradiance of 1200 W / m ² in the effective level must not be exceeded.

Depending on this standard, for example, a maximum radiation duration of 8.33 minutes for a subject of type II results from the division of the erythema-effective threshold radiation of 250 J / m ² and the max. Irradiance Eer of 0.3 W / m ² .

However, an exact determination of the time and intensity of UV radiation in the case of a trained callus, applied sunscreens, cosmetics or the like is practically not possible.

Due to these essentially empirical specifications, the change is in no way particularly artificial

UV radiators taken into account, for example. Aging or the replacement of tubes, the temperature fluctuations caused by the entire irradiation time of a sunbed, and the like. In addition, the correct use and cleaning of

Sunbeds or the like, for example, the reflection behavior as well as the UV emission by curing, for example, acrylic cover plates, so that it can hardly be assumed that the manufacturer's information regarding the spectrum and the radiation power, for example of a sunbed, is also applicable.

The state of the art for determining the

Skin photosensitivity is limited to devices for color determination that are referred to as chromameters or Mexameter are known. These devices use optically visible radiation, for example white RGB light or spectrally subdivided radiation in the red, green, yellow or blue spectral range. However, since the scattering coefficient μs is larger than that in these wavebands

3, only a direct reflection on the skin can be measured, since the amount of radiation reflected on the surface is always higher than that of the absorbed one. Therefore, such devices are not suitable for giving indications of a limitation of a UV radiation dose or the radiation duration for a test person.

Against this technical background, the object of the invention is to provide devices and methods which allow verifiable and reproducible statements regarding the maximum radiation dose and / or the maximum radiation duration of a test subject with a UV lamp.

Such a device is capable of determining the permissible radiation duration and / or radiation dose of the human skin with UV radiation, which has at least one UV emitter for emitting UV radiation, at least one UV sensor for recording the UV radiation in and / or UV radiation remitted on the skin and an evaluation device for determining the radiation absorption.

For this purpose, the UV radiator is designed such that it preferably irradiates the human skin locally, for example by a diode that emits UV radiation. Alternatively, the UV radiation from a sunbed or the like can be used if, for example, an optical waveguide, if necessary. with suitable filter devices, the radiation emitted is directed to the skin of a test person.

The UV radiation that has penetrated into the skin, is scattered there and then remitted is received by the UV sensor and the radiation absorption can then be determined by an evaluation device. Significantly, the absorption of the applied UV radiation in the skin takes place precisely at the point or in the skin layers which are essential for the natural formation of light swellings, as a result of which in particular the density or the thickness of the layer of the melanin granules and that of the layer of Keratinocyte-absorbed melanosomes can be determined.

Corresponding to the degree of remission, for example between 0% and 100%, this scaling can be stored with a grid of the permissible threshold dose and exactly one threshold dose can be reproducibly assigned according to each measurement.

Compared to the previous division into just four or five photo types by inspection by a trained operator, the device according to the invention allows a much finer resolution, for example between 1 and 10,000, and the measurement result is particularly reproducible and independent of subjective assessments , In addition, the threshold dose is derived on the basis of the quantity of available melanin granules or melanosomes and can thus be kept well below erythema formation.

For a sufficient quality of the measurement and the determination of the radiation absorption by an evaluation device, it has proven to be expedient if the UV lamp has a Emits UV radiation in which an absorption coefficient μa is greater than or equal to a scattering coefficient μs.

For this purpose, it will also be provided that the UV lamp emits UV radiation of a wavelength smaller than the diameter of a cell nucleus. As a result, there is radial scattering, a Rayleigh scattering in the cell tissue on, for example, collagen fibrils, supramolecules or cell membranes, with which an exact thickness and density of a cell layer such as that of the melanin granules can be derived from the remission.

As a result of this measure, an exact determination of the absorption on a light callus takes place, since at longer wavelengths, according to the known devices, a forward or forward and backward scattering occurs on Mie scatterers, for example on cell nuclei, mitochondria or, in the visible range of light Organelles, which makes it difficult to identify light calluses, because the quality of the skin surface itself, applied cosmetics,

Blood circulation fluctuations and the like lead to considerable deviations of the measurement results from one another.

If the absorption coefficient μs and the scattering coefficient μa are the same, a UV-sensitive skin can be easily recognized compared to a less sensitive one. If the scatter predominates, the skin is sensitive; if the absorption predominates, the skin type is less sensitive. Furthermore, the size and the formation and density of the melanosomes can be determined indirectly. The cap-shaped melanosomes have an average edge length of approx. 350 nm. If the edge length is now shorter, the melanosomes are scattered strongly forward and strongly backward. As a result, a large part of the measuring radiation is reflected and by that UV sensor detected. If the edge length is approx. 350 nm, the melanosomes are strongly radially scattered by UV radiation, which also impinges on neighboring cells and melanosomes, which means that absorption predominates. With longer edge lengths of the melanosomes there is again a strong forward and backward scattering, but a large part of the incident UV radiation is absorbed by the melanosomes and as a result predominates the absorption.

Suitable UV emitters are preferably those which emit UV radiation with a wavelength of 345 nm to 355 nm, in particular of 350 nm. With the latter value, the absorption coefficient μa is 12.3 cm ^"1 and the scattering coefficient μs is 12.5 cm ^"1 , which means that these coefficients are almost the same, but the absorption is still slightly predominant. For this purpose, reference may already be made to FIG. 1 here.

It can be expediently provided that the at least one UV emitter and / or the at least one UV sensor is or are arranged in a housing of a hand-held measuring device. An arrangement of both the UV radiator and the UV sensor in a common housing is preferred, whereby a measuring device that is independent of a further radiation source is provided. Alternatively, however, that of a sunbed or the like can also serve as the radiation source.

In a constructive embodiment it can be provided that the

Housing has a contact surface for laying on the skin of a subject and that the UV lamp and the UV sensor are arranged at an angle to each other such that a reflection of a beam on the optical axes of the UV lamp and the UV sensor in a Penetration depth of up to 1 mm below the contact surface. As a result of this measure, a remission of the UV radiation is resumed by the UV sensor, which reflects the formation of swelling of light in the crucial skin layers, in particular those in which melanins are formed or those which contain the precursor dopainee, and that the melanin granules and those of the oxidized melanins.

Such a defined penetration depth is completely sufficient for tanning salons or the like, in particular even if an average value is formed from several measurements. In special applications, for example in light therapy, it can also be provided in a constructive configuration that the depth of penetration can be adjusted. It is then possible to individually measure the three layers of skin mentioned at a given location in an extremely exact manner and to determine the respective absorption capacity.

In a constructive embodiment it is provided that the optical axes of the UV radiator and the UV sensor span an angle α between 70 ° and 110 °, with a

Adjusting the angle α can vary the depth of penetration. Alternatively or additionally, it can be provided that the height and / or the distance between the UV lamp and the UV sensor above the contact surface can be adjusted for a variation in the penetration depth.

Since the formation of swellings of light does not take place evenly over the entire surface of the skin, e.g. in the areas of the skin that are regularly exposed to sunlight, it is significantly different than in the areas that are mostly covered by clothing, so it has proven to be useful if there are several Measurements, e.g. three measurements, an average is formed, for which purpose the device expediently has a computer unit. This can then be further assigned to a measurement and / or is preferably assigned a threshold dose to the mean value from several measurements. This will always be useful if a single UV radiation source is used.

In order to also do justice to the uncertainty factor of UV emitters, it can further be provided that the proportion of the erythema-effective in an electronic memory

UV radiation intensity of a radiation source is stored and that the computer unit calculates the maximum radiation duration and / or radiation dose. Such data on the erythema-effective UV radiation intensity can be made available by a spectral measurement of the radiation source by its manufacturer, for example.

In a further constructive embodiment, an interface is provided, via which the individual data of a subject can be stored and called up. Such an interface can be a chip card writing and / or reading device, which can then store, for example, the individual maximum radiation duration and / or radiation dose on a chip card, which data can then be read out by a control unit of a radiation source, which then automatically opens the correct, maximum radiation duration and / or radiation dose is set. Alternatively, such an interface can be designed as a USB or RS-232 interface, so that at least one radiation source can also be controlled directly or via a central computer via corresponding cable connections. Wireless networks according to the prior art can also be used for such data transmission. Different areas of the body of a test person can easily be distinguished, for example the trunk and face, if both areas are measured separately and, for example, a sunbed has UV lamps that can be controlled and regulated independently of one another. In particular, it can further be considered that a different irradiation power achieves the same radiation times for both radiation sources, for example.

If the physical changes in the UV radiation source are also to be taken into account or, for example in the case of a tanning bed, different distributions of UV radiation over the length thereof, a device is expedient, in particular in a combination with those described above

Features in which a housing has two pairs of UV sensors, the UV sensors in each pair being oriented in opposite directions and the two pairs being arranged rotated by 90 ° relative to one another. As a result of this measure, the UV radiation in the tanning tunnel, for example a sunbed, can be avoided from all sides via a circular arc of 360 °. Carried out through the tanning tunnel of a sunbed, the UV radiation can be measured locally further, so that, for example, different radiation doses or radiation times can be taken into account in the head, neck and leg area in connection with the corresponding skin measurements.

In a constructive embodiment it can be provided that the UV sensors are designed directly as UV sensors, but it is preferred that the UV sensors are formed by free ends of optical fibers. On the one hand, optical fibers attenuate the recorded spectrum and, on the other hand, this makes it possible to use optical fibers on one common, second UV sensor to end, especially all four optical fibers.

However, a filter facial expression can be assigned to a free end of an optical waveguide, with one in particular being thought of by which the spectral weighting of the UV emitter used is adapted to the erythrema active curve. The short-wave portion of the remitted radiation will experience a higher reflection at the input of the optical waveguide than the long-wave portion and the long-wave portion also an improved transmission.

It can be provided that the second UV sensor has a linear characteristic curve over the erythema-active spectrum.

However, an alternative and preferred is a characteristic curve of the second UV sensor that corresponds to the erythema-active spectrum.

In both cases, preference is again given to providing a reference wavelength of 350 nm, since a large number of the UV lamps in question have an emission maximum in the region of this wavelength. Emission maxima from 360 nm to 370 nm hardly influence the measured value at 350 nm, since these peaks are a maximum of 20% higher than the emission value at 350 nm. the subdivision of the UV spectral range mentioned at the beginning.

The distance between a pair of UV sensors suitably corresponds to the height of a human body on a sunbed, a distance between approximately 20 cm and 35 cm. The device according to the invention can then be opened in a simple manner for one or preferably for several measurements the support of a tanning bed is put on and pushed through the tanning tunnel, whereby there is an exact distance to the lower and upper radiation sources.

Alternatively or additionally, it can be provided that the device has a distance measuring device, for example on an ultrasound basis. As a result of this measure, too, the UV radiation source is measured precisely in the area where the UV radiation strikes the body of a test subject.

In a further embodiment, a temperature sensor can also be provided, so that temperature compensation is also possible. In a further development of the invention, the measurement of the UV emitter or UV emitters can also take place in a controlled manner by the temperature sensor when their combustion wall temperature has reached an optimum value, for example after being switched on, which corresponds to that when a test person is irradiated.

Data from the measurement, for example of a sunbed, is expediently stored in an assigned electronic database, so that the individual, maximum radiation duration and / or radiation dose is measured by the computer unit from the individual data of the subject from a measurement of the skin and the UV radiation source from a measurement of the same can be calculated and the UV radiation source (s) is / are also controlled directly via appropriate interfaces up to an automatic switch-off when the threshold dose is reached. An overdose of UV radiation is largely excluded.

Correspondingly, in a method for determining the permissible radiation duration and / or radiation dose of the human skin with UV radiation, preferably under Use of one of the devices described above, based on an individual measurement of the absorption of the erythema-effective UV radiation in a layer of the test person's skin forming a swell and the assignment of a threshold value of UV radiation. This radiation can take place by means of direct UV radiation, for example by means of a UV diode or also via an optical waveguide. Fluorescence photometry offers an alternative to radiation.

An average value is expediently formed from a plurality of individual measurements by a computer unit, to which a threshold dose is further assigned.

For example, three individual measurements are preferably carried out at different locations on the skin in order to take local differences of the skin into account.

It can also be provided that individual measurements are carried out at different skin depths in order to determine the calluses in certain skin layers.

From the threshold value and the stored data of a UV radiation source, for example taken from a data sheet, preferably from a direct measurement, the

Computer unit also determined a maximum radiation duration or radiation dose.

In an advantageous manner, the method according to the invention can also be used during tanning of a test person. At the same time, both the changes in the UV radiation source (s) and the skin of a test person are monitored and this UV radiation source (s) is switched off when the UV defense is exhausted. The invention is explained in more detail with reference to the drawing, in which an exemplary embodiment and diagrams are shown only schematically. The drawing shows:

1 in dashed lines the scattering coefficient μs and the absorption coefficient μa over the wavelength specified in nanometers,

2 shows a diagram to illustrate the remission,

3 shows a device according to the invention for determining the UV absorption of the skin and the measurement of a UV lamp,

Fig. 4 shows in detail the arrangement of a UV lamp and a UV sensor of the device according to Fig. 3 and

Fig. 5 shows a section through the free end of an optical fiber.

FIG. 1 shows the absorption coefficient μa of the dimension l / cm and the scattering coefficient μs of the dimension l / cm over the wavelength of the light in nanometers. The absorption coefficient μa has relative maxima in the blue area at around 400 nanometers and in the green area at around 550 nanometers.

In the wavelength range of 400 nanometers, the absorption is due to the hemoglobin, in other words in such deep skin layers that do not allow any statement about swelling of light for the UV range. In particular, when the skin is irradiated with light in the visible range, Mie scatterers are scattered, which are essentially forward or forward and backward sprinkle aligned. This is due to the longer wavelength of visible light compared to the dimensions of the absorbing structures such as cell nuclei, mitochondria or organelles. As a result, known devices that work with visible light could only detect one reflection. It is not possible to draw any conclusions about the strength of a callus, since fluctuations in blood flow and much more besides are falsified by the nature of the skin surface itself, applied cosmetics, and such results, which is compensated for by large tolerances and oversized measurement windows of the known devices.

According to the invention, UV radiation is provided for determining the permissible radiation duration and / or radiation dose, which preferably has a wavelength between 345 nanometers to 355 nanometers and in particular a wavelength of 350 nanometers. Figure 1 shows that there is the scattering coefficient microseconds with a value of 12.3 cm ^"1 uA the absorption coefficient of 12.5 ^{cm" 1} corresponds to the greatest possible extent, even if the absorption prevails there.

Due to the selected wavelength, there is no real reflection in and / or on the skin, but a remission. Here is a gem. Figure 2 incident light beam 1 penetrate into the skin 2 and the light beam 1 is radially scattered on Rayleigh scatterers due to the selected wavelength and, indicated by the rays 3, partially remitted and partially, indicated by rays 4, absorbed.

The density and / or the thickness of the melanin granules and / or the melanosomes embedded in the layer in keratinocytes and thus a statement about the effectiveness of a can be derived from the rays 3 representing the remission Bumps of light meet and can be based on this in turn specify a threshold dose. This should be well below that of erythema formation in order to reliably rule out damage.

Thus, an individual measurement of the absorption of the erythema-effective UV radiation can take place in a layer of the skin of a subject forming a swell, which measurements can then be assigned a threshold value of UV radiation by a computer unit, the UV radiation being direct or by means of fluorescence photometry can be done.

A mean value is expediently calculated from a plurality of individual measurements at different locations, so that a threshold value can be assigned to an average value of the skin, possibly also for differently irradiated parts of the body.

A device 5 according to FIG. 3 is provided for carrying out the measuring method, which is shown only schematically there. The device 5 according to FIG. 3 has a measuring device 6 with an evaluation device (not shown) for determining a radiation absorption, which is emitted via a UV lamp 7, according to FIG. 4, for example in the form of a diode, for emitting UV radiation and a UV sensor 8 for receiving the UV radiation remitted in and / or on the skin. The UV lamp 7 and the UV sensor 8 are designed as a hand-held measuring device within a common housing 9

Device 5 arranged.

For the measurement of the skin, the measuring device 6 or the device 5 has a support surface 10 which is placed on the skin 11 of a subject, see FIG. 4 therefore the UV lamp 7 and the UV sensor 8 are always correctly positioned with respect to the skin 11.

For operation, for example in tanning salons or the like, it is sufficient if the light calluses form

Layers of the skin are measured at a depth of approximately 0.5 mm to 1 mm, that is to say a reflection of a beam on the optical axis 12 of the UV lamp 7 and the optical axis

13 of the UV sensor 8 takes place at a penetration depth e of up to 1 mm below the contact surface 10.

It can be provided, for example when measuring individual skin layers of very different thicknesses or for sensitive light therapy, to measure different skin layers and therefore to make the penetration depth adjustable, for example in which the height and / or the distance of the UV lamp 7 and the UV sensor 8 can be adjusted above the support surface 10 or the angle between the optical axes 12, 13, which in particular has values from 70 ° to 110 °.

A computer unit, not shown, preferably calculates an average value from a plurality of measurements on the skin by means of the measuring device 6 and assigns a threshold dose to it. This can be done using a display

14 are displayed.

However, the proportion of the erythema-effective ones is expedient in an electronic memory (not shown) in the device 5 or in an external memory

UV radiation intensity of one or more radiation sources is stored and, after selection of the radiation source, the computer unit can calculate the maximum radiation duration and / or radiation dose and display this on the display 14. For this purpose, the device 5 also has three interfaces, via which the individual data of a subject and / or the data of a UV lamp could be stored externally and called up again. Furthermore, one or more radiation sources can be controlled via one of these interfaces, possibly also via a central computer, and the predetermined maximum radiation duration and / or radiation dose can be specified in this way.

Since tanning salons often use chip card systems for billing, such an interface can be a chip card reading and writing device 15, which is only indicated here by a slot.

Appropriately covered by a cap 16 and thus protected from contamination, for example an RS-232 interface 17 and / or a USB interface 18 are also provided next to a reset switch 19 for direct connection to a computer. Wireless interfaces can also be used alternatively or additionally.

It is more expedient than storing data from a sunbed or the like according to the manufacturer's information to measure it individually in order to reliably detect changes in the radiation, for example due to aging, pollution or the like. For this purpose, the device 5 also has two pairs of UV sensors 20-23, which are formed by the free ends of optical waveguides 24-27 and which in each case in opposite, parallel housing walls 28-31 of the essentially rectangular housing 9 are oriented such that a pair of UV sensors 20, 21 and 22, 23 are oriented in opposite directions, the respective pairs of UV sensors 20, 21 and 22, 23 being rotated by 90 ° with respect to one another. In this way, the radiation can essentially be measured in one plane over a complete circular arc of 360 °.

The free end 37 of an optical waveguide 38 can be arranged within a housing 39, the shape of which is largely based on that of a signal lamp to be installed in a panel with a head 40 and a foot 41 with an external thread 42, cf. Fig. 5. The housing 39 further accommodates a filter facial expression which is assigned to the free end 37 of the optical waveguide. The filter facial expressions exist in the embodiment according to. 5 from a plastic disc 43 held freely by the head 40 in front of the end 37 of the optical waveguide 38 and two further plastic discs 44, 45 pushed onto the optical waveguide 38 and held by the foot 41, for this purpose with central, conical bores 46, 47 are provided. By means of this filter facial expression, the short-wave portion of the remitted radiation is reflected and the long-wave portion also experiences improved transmission.

Since the distance between the two UV sensors 20, 21 corresponds approximately to the height of a human body from approx. 20 cm to 35 cm on a sunbed, the device 5 can be easily mounted on a housing wall 29 designed as a flat bottom after removing the cap 16 on the lying surface of a tanning bed, for example to make several measurements along its length, such as in the head, neck or leg area.

The resulting UV radiation is received by the UV sensors 20-23 and fed via the optical fibers 24-27 to a common, second UV sensor 33, so that an average value of the irradiance is formed, it being possible to think about different measuring ranges to provide the UV spectrum. The measured radiation power of a sunbed then serves as the basis for calculating the maximum radiation duration, for which purpose this data can be stored internally or externally, which can then be called up via one of the interfaces 15, 17, 18.

A distance measuring device 34 can also be provided so that the correct distance from a radiation source can always be maintained.

A temperature sensor 35 also allows different temperatures to be taken into account, for example after a long or short lighting time of a radiator. In particular, the temperature sensor 35 only allows a UV radiation source to be measured when its combustion wall temperature corresponds to the norm.

The device according to the invention is preferably supplied with power via rechargeable batteries, for the charging of which a plug connection 36 for a power supply unit is ultimately provided.

Claims

Device and method for determining a permissible irradiation of human skin with UV radiation

1. Device for determining the permissible radiation duration and / or radiation dose of human skin with UV radiation, comprising at least one UV lamp (7) for emitting UV radiation, at least one UV sensor (8) for recording the UV radiation remitted in and / or on the skin (11) and an evaluation device for determining the radiation absorption.

2. Device according to claim 1, characterized in that the UV lamp (7) emits UV radiation in which an absorption coefficient μs is greater than or equal to a scattering coefficient μa.

3. Device according to one or more of the preceding claims, characterized in that the UV radiator (7) emits UV radiation of a wavelength smaller than the diameter of a cell nucleus.

4. Device according to one or more of the preceding claims, characterized in that the UV lamp (7) emits UV radiation of a wavelength of 345 nm to 355 nm.

5. The device according to one or more of the preceding claims, characterized in that at least one UV lamp (7) and / or at least one UV sensor (8) is arranged in a housing (9) of a hand-held measuring device respectively . are .

6. The device according to one or more of the preceding claims, characterized in that the housing (9) has a support surface (10) for laying on the skin (11) of a subject and that the UV lamp (7) and the UV Sensor (8) are arranged at an angle (α) to one another such that a reflection of a beam on the optical axes (12, 13) of the UV emitter (7) and the UV sensor (8) at a penetration depth (e) of up to 1 mm below the contact surface (10).

7. The device according to one or more of the preceding claims, characterized in that the depth of penetration (e) is adjustable.

8. The device according to one or more of the preceding claims, characterized in that the optical axes (12, 13) span an angle (α) between 70 ° and 110 °.

9. The device according to one or more of the preceding claims, characterized in that the angle (α) is adjustable for a variation in the penetration depth (e).

10. The device according to one or more of the preceding claims, characterized in that the height and / or the distance of the UV radiator (7) and the UV sensor (8) over the bearing surface (10) for a variation of the penetration depth (e ) is adjustable.

11. The device according to one or more of the preceding claims, characterized in that one Computer unit an average is formed from several measurements.

12. The device according to one or more of the preceding claims, characterized in that the computer unit assigns a threshold dose to a measurement and / or an average value from a plurality of measurements.

13. The device according to one or more of the preceding claims, characterized in that the proportion of an erythema-effective UV radiation intensity of a radiation source is stored in an electronic memory and that the computer unit calculates the maximum radiation duration and / or radiation dose.

14. The device according to one or more of the preceding claims, characterized in that an interface (15, 17, 18) is provided, via which data can be stored and called up.

15. The device according to one or more of the preceding claims, characterized in that at least one radiation source is controlled via the interface.

16. The device, in particular according to one or more of the preceding claims, characterized in that a housing (9) has two pairs of UV sensors (20, 21, 22, 23), that in each pair the UV sensors (20, 21 22, 23) are oppositely oriented and that the two pairs are arranged rotated by 90 ° relative to each other.

17. The device according to one or more of the preceding claims, characterized in that the UV sensor (20,21 _/ 22,23) of free ends of optical fibers (24-27) are formed.

18. The device according to one or more of the preceding claims, characterized in that a filter end is assigned to a free end of an optical waveguide, through which a short-wave portion of the reflected radiation is reflected to a greater extent than a long-wave portion.

19. The device according to one or more of the preceding claims, characterized in that optical fibers (24-27) end on a common second UV sensor (33).

20. The device according to one or more of the preceding claims, characterized in that the four optical fibers (24-27) end on a common second UV sensor (33).

21. The device according to one or more of the preceding claims, characterized in that the second UV sensor (33) has a linear characteristic over the erythema-active spectrum.

22. The device according to one or more of the preceding claims 1-19, characterized in that the second sensor has a characteristic curve corresponding to the erythema-active spectrum.

23. The device according to one or more of the preceding claims, characterized in that the distance between a pair of UV sensors (20, 21) corresponds to the height of a human body on a sunbed.

24. The device according to one or more of the preceding claims, characterized in that a distance measuring device (34) is provided.

25. The device according to one or more of the preceding claims, characterized in that a temperature sensor (35) is provided.

26. The device according to one or more of the preceding claims, characterized in that a UV measurement is triggered by the temperature sensor (35) when an optimal combustion wall temperature of a UV radiation source to be measured, a sunbed or the like is reached.

27. The device according to one or more of the preceding claims, characterized by an assigned database for storing the data measured by the second UV sensor (33).

28. The device according to one or more of the preceding claims, characterized in that the computer unit calculates the maximum radiation duration and / or radiation dose from the individual data of a subject and a UV radiation source.

29. The device according to one or more of the preceding claims, characterized in that when the maximum radiation duration and / or radiation dose is reached, the UV radiation source is switched off.

30. Method for determining the permissible radiation duration and / or radiation dose of the human skin with UV radiation, in particular with a device according to one or more of the preceding claims, characterized by an individual measurement of the absorption of the erythema-effective UV radiation in a layer of the skin of a test subject forming a swell and the assignment of a threshold value of UV radiation.

31. The method according to claim 26, characterized in that the measurement is carried out by means of direct UV radiation.

32. The method according to claim 26, characterized in that the measurement is carried out by means of fluorescence photometry.

33. The method according to one or more of the preceding claims, characterized in that an average is formed from several individual measurements.

34. The method according to one or more of the preceding claims, characterized in that the individual measurements take place at different locations.

35. The method according to one or more of the preceding claims, characterized in that the individual measurements are carried out in different skin depths.

36. The method according to one or more of the preceding claims, characterized in that a maximum radiation duration and / or radiation dose is determined from the threshold value and stored data of a UV radiation source.

37. The method according to one or more of the preceding claims, characterized in that the data from actual data from a measurement of the UV radiation source.

38. The method according to one or more of the preceding claims, characterized by its use during tanning of a subject.