MEASURING SYSTEM AND MEASURING METHOD FOR DETERMINING SUN PROTECTION FACTORS OF SUN PROTECTION PRODUCTS

Description

[0001] The invention describes a measuring system and method for qualifying cosmetics and sunscreens for which a sun protection factor (SPF) or a protection factor yet to be defined is specified. State of the art

[0002] In DE 10 2014 003 470 A1, a measuring system for determining sun protection factors of sunscreens is disclosed, comprising a beam source device wherein the beam source device has two or more separate beam sources, a spectrometer and a control device, wherein the wavelength spectra of the beam emitted by at least two of the separate beam sources are different, as well as a corresponding method for determining the sun protection factors.

[0003] WO 2017 / 067 545 A1 describes a measurement system and method for determining a sun protection factor (SPF) for products such as cosmetics and sunscreens. This method involves taking two measurements of light backscatter at the skin surface in vivo, in vitro, or on skin models (animal or artificial) before and after application of the sunscreen. The SPF is then calculated from these measurements. Unlike previously standardized methods, this system uses a fixed distance between the illumination surface and the detection area on the skin. The SPF can be determined according to existing standards or for additional wavelengths or wavelength ranges (e.g., UVA, VIS, NIR, IR).

[0004] US Patent 2018 / 0202927 A1 describes a sunscreen detector for use with portable devices. One embodiment of the sunscreen detector comprises a lighting system configured to illuminate an area of ​​skin with ultraviolet and infrared light, and a sensor system configured to detect the amount of ultraviolet and infrared light reflected from that area of ​​skin. The sunscreen detector is configured to analyze the data collected by the sensor system to generate a notification to the user indicating whether sunscreen should be applied. In one embodiment, the lighting system includes a first LED that emits light in the UVB range (from approximately 290 nm to approximately 320 nm) and a second LED that emits light in the UVA range (from approximately 320 nm to approximately 400 nm). The light sources can be pulsed.

[0005] All existing methods approved by the European Union (EU) and the American Food and Drug Administration (FDA) for determining SPF are harmful to the test subjects, as they induce erythema, a light-induced inflammatory skin reaction (COLI PA - European Cosmetic, Toiletry and Perfumery Association: Colipa SPF Test Method 94 / 289, 1994; ISO Standards 24442, 24443, 24444). Therefore, both the FDA and the EU have repeatedly emphasized that future research must focus on new methods for characterizing the protective effect of sunscreens in order to avoid long-term adverse effects on test subjects (European Commission, Standardisation Mandate Assigned To CEN Concerning Methods For Testing Efficacy Of Sunscreen Products, M / 389 EN, Brussels, 12 July 2006).

[0006] This invention aims to accomplish this task. The existing methods are defined in various sources: I. Procedures defined in standards and regulations: a. ISO 24444 defines a method for the in vivo determination of SPF. The method is based on the induction of erythema on the skin of test subjects by exposure to UVB radiation. Therefore, the method is harmful. To reduce the dependence of the result on interindividual variations in skin properties, the method must be performed on several test subjects. b. ISO 24443 defines an in vitro method for determining the UVA protection factor (UVAPF). The sunscreen is applied to a plastic plate so that a transmission spectrum of the sunscreen can be measured. Due to uncontrollable variations in the procedure, the transmission spectrum is scaled to match the result of the erythema test according to ISO 24444 and is therefore dependent on how that test was performed.The plastic plate used, with its roughened surface, is a relatively unrealistic skin model. c. ISO 24442 defines an in vivo method in which the UVA protection factor is determined by means of the minimum UVA dose required to produce irreversible pigmentation (suntan) of the skin. This method also results in a change to the subject's skin. d. FDA Final Rules 2011, originally published in the Federal Register on August 27, 2007 (72 FR 49070) and codified as the Broad Spectrum Test (21 CFR 201.327(j)) and Sun Protection Factor (SPF) Test (21 CFR 201.327(i)) or in a newer version as 21 CFR 201.352 (http: / / www.ecfr.gov / cgi-bin / text-idx?SID=5555a0dd8b6d83a8570676d9a44bb6ef&mc=true&node=pt21.5.352&rgn=div5). II. Patented methods: a. DE 198 28 497 A1 describes a method in which, as in ISO 24444, erythema is produced in test subjects by UV irradiation of the skin. become.In contrast to ISO 24444, these are detected by reflection spectroscopy. This method is therefore also harmful. The optical effect (protection) of the sunscreen is not detected by direct optical measurements, but rather via a biological reaction of the body. b. In DE 10 2004 020 644 A1, a method is described in which the generation of radicals by UV exposure in vivo is quantitatively measured using electron spin resonance (ESR). Here, too, the optical effect of the sunscreen is only detected indirectly. In addition, ESR measurement is technically complex and requires relatively large, stationary devices (tabletop units). They are also sensitive to interference from high-frequency radiation or rapid, temporary magnetic field changes, such as those caused by electrical switching processes. III. Publications: a. In Bendova H, et al.In Toxicology in vitro (2007), 1268-1275, methods of transmission spectroscopy using various films as skin models are compared. The determined protection factors depend strongly on the film used. A significant correlation of the protection factors with the SPF from ISO 24444 was not found. b. In Ruvolo E, Kollias N, Cole C, Photodermatol Photoimmunol Photomed (2014), 30: 202-211, a method is presented in which a UVB transmission measurement with plastic substrates and an in vivo backscatter measurement on the skin in the UVA range are combined. The transmission measurement is adapted to the UVA backscatter measurement by scaling, thereby achieving good agreement with the in vivo test of the SPF according to ISO 24444. The measurement setup for the UVA backscatter measurement includes a fiber bundle that is placed on the skin. The measurement is performed using a large number of illumination and detection fibers at different distances from each other.The sum of the light intensities from the detection fibers is detected; therefore, there is no defined distance between the illumination surface and the detection surface, but rather a summation of all distances. In the method according to the invention, backscattering is measured at several well-defined distances. c. In Sohn M, Korn V, Imanidis G, Skin Pharmacol Physiol, (2015), 28: 31-41, skin from the pig ear is tested as a substrate for in vitro measurements of transmission. Compared to measurements with standardized plastic substrates, a better correlation with the SPF determined in vivo is obtained. This shows that a realistic skin model is essential for determining sun protection factors. The transmission measurement was performed with and without sunscreen.However, the error of such a measurement is highly dependent on the layer thickness used (thickness of the separated layer of the pig ear) and the surface roughness relative to the change caused by the (identical, standardized) amount of sunscreen. In the measurements presented in this publication, the errors are only evaluated against the SPF determined in vivo according to ISO 24444:2010, not against each other. Furthermore, only one type of sunscreen (oil-in-water) was used, which, due to oil droplet formation, has particularly high scattering properties, thus reducing the impact of surface changes.

[0007] The application range of previous methods using UVB radiation (solar simulator, i.e., "sun simulator" with a predetermined wavelength-specific intensity between 290 and 400 nm corresponding to solar radiation at sea level) and with limited possibilities using UVA radiation (erythema does not occur as with UVB, higher penetration depth than UVB into the skin = larger volume) is to be extended without restriction to UVA, UVB, the visible and near-infrared or infrared range for the determination of corresponding sun protection factors with the solution according to the invention. Disadvantages of previous methods

[0008] Elevated doses of UV radiation can damage tissue and cellular components. Skin aging and, in the worst case, skin cancer are well-known consequences. For decades, a rising number of new skin cancer cases has been observed, currently amounting to approximately 20,000 cases per year in Germany. The main cause is repeated, intense UV exposure, such as that experienced during summer vacations, especially in childhood and adolescence.

[0009] Existing methods for evaluating sunscreens are inadequate because they are either invasively tested on subjects by causing erythema or are tested unphysiologically on plastic carriers as a skin model.

[0010] Current in-vivo SPF determination has several shortcomings. This method only considers a spontaneous biological effect (induced sunburn) triggered by UVB radiation. However, it is now known that UVA radiation can also cause severe skin damage, including skin cancer. Furthermore, SPF determination is an invasive procedure, as it induces sunburn in test subjects. Therefore, both the U.S. Food and Drug Administration (FDA) and the European Union have repeatedly emphasized that future research must focus on new methods for characterizing the protective effect of sunscreens to avoid long-term adverse effects on subjects. In-vivo SPF can only be determined in the UVB range, whereas long-term damage can also occur from other spectral ranges.

[0011] It is therefore an object of the invention to provide a method and a device that in particular reduce the stress caused by radiation on the measuring body and at the same time provide high-quality analysis results.

[0012] The problem is solved by means of the measuring system according to claim 1. Advantageous embodiments of the invention are set out in the dependent claims.

[0013] The measuring system according to the invention for determining sun protection factors comprises a beam source device having two or more separate beam sources. The measuring system also includes a spectrometer for detecting the light reflected from a sample body and a control device. According to the invention, the wavelength spectra of at least two of the beams emitted by the separate beam sources are different from one another.

[0014] The measuring system according to the invention enables the targeted adaptation of the overall spectrum to various applications through the targeted control of the light sources. Furthermore, by selectively superimposing the individual spectral ranges of the light sources, uniform illumination is achieved in both the UVA wavelength range from 380 nm to 315 nm and the UVB wavelength range from 315 nm to 280 nm. This also allows for the selection of a maximum radiation dose, either in the form of an individual dose (e.g., 0.1 MED) or a limit value. In total, this minimizes the radiation dose for a test subject. Finally, the light source can also be used for other measurement tasks, e.g., for measuring the photodegradation of sunscreens, for which a sun-like spectrum is required. According to the invention, the light source comprises eight LEDs in a wavelength range from 290 nm to 400 nm with mid-wavelengths in the range of 295 nm and 310 nm.325nm, 340nm, 355nm, 365nm, 385nm, and 395nm with typical spectral widths of the (FWHM) of 10-20nm.

[0015] The pulsed and adjustable beam sources allow for flexible temporal control of the illumination as well as intensity control via pulse wave modulation (PWM). The combination of several individually controllable polychromatic beam sources and a spectrometer enables both the measurement of a continuous spectrum and the filtering of fluorescence and scattered light. The measurement system is optionally designed so that the individual beam sources can be controlled separately, meaning that different parameters and settings can be defined for each individual beam source. These parameters include current, intensity (independent of current via PWM), and temperature. Furthermore, the individual beam sources of the measurement system emit different wavelength spectra. These are preferably polychromatic light sources, such as UV LEDs.They are pulse-controlled and adjustable with respect to the intensity they emit. According to the invention, the radiation sources are dynamically controllable, i.e., the parameters are dynamically adjusted during a measurement sequence depending on the measurement data (e.g., skin remission). This allows for better utilization of the detector's limited dynamic range.

[0016] In a further embodiment of the invention, the spectrometer can be controlled by means of the control unit, and the signals measured by the spectrometer can also be processed by means of the control unit. The detection window and the resolution of the spectrometer are set by means of the control unit, and the detected signals are stored, processed (e.g., amplified), and displayed.

[0017] According to the invention, the individual beam sources of the beam source device can be controlled separately. This enables targeted control of the beam sources and targeted adaptation of the overall spectrum to different applications. Furthermore, by selectively superimposing the individual spectral ranges of the beam sources, uniform illumination is achieved, thus also allowing for the selection of a maximum radiation dose or a limit value. In total, this minimizes the radiation dose for a test subject. Finally, the light source can also be used for other measurement tasks, e.g., for measuring the photodegradation of sunscreens, for which a sun-like spectrum is required.

[0018] In a further embodiment of the invention, the measuring system has a beam source control by means of which the individual beam sources of the beam source device can be controlled separately.

[0019] In a further embodiment of the invention, the measuring system has a beam source control by means of which the beam source device can be controlled.

[0020] In a further embodiment of the invention, the wavelength, exposure time, and / or intensity of the radiation emitted by the individual radiation sources can be controlled separately by means of the beam source control. This enables targeted control of the radiation sources and targeted adaptation of the overall spectrum to various applications. Furthermore, uniform illumination is achieved through defined superposition of the individual spectral ranges of the radiation sources, thus also allowing for the selection of a maximum radiation dose or a limit value. In total, this minimizes the radiation dose for a test subject. Finally, the light source can also be used for other measurement tasks, e.g., for measuring the photodegradation of sunscreen products.

[0021] In a further embodiment of the invention, the beam source control is arranged separately from the control device. The control device is typically a PC or notebook computer with appropriate computer software and is connected to the beam source control via a data line.

[0022] In a further embodiment of the invention, the beam source control is controllable by the control unit. The control unit is typically a PC or notebook computer with appropriate computer software and is connected to the beam source control via a data line. The control unit controls the wavelength range, exposure time, and / or intensity of the light emitted by the beam source via the beam source control.

[0023] In a further embodiment of the invention, the beam source control is connected to the spectrometer and is suitable and designed to receive signals from the spectrometer and / or send control commands to the spectrometer. The detection window and the resolution of the spectrometer are determined by means of the beam source control, and the detected signals are stored and processed (e.g., amplified).

[0024] The problem is also solved by means of the inventive method according to claim 8.

[0025] The inventive method for determining sun protection factors comprises three process steps: In the first process step, a first radiation source is controlled by a radiation source device comprising several radiation sources. In the second process step, a second radiation source is controlled by a radiation source device comprising several radiation sources. In the third process step, a measuring body is irradiated with the radiation of a complete spectrum from the first and second radiation sources. According to the invention, the control command for the first radiation source for irradiating the measuring body differs from the control command for the second radiation source.

[0026] This method offers numerous advantages over the prior art. For example, in the method according to the invention, only a small dose of light, below the MED (minimum erythema dose; individually tailored for skin types) or below the maximum permissible irradiation (MPI value; for UV and other wavelength ranges), is applied to the measuring body. Due to these low light doses, the method is also suitable for non-destructive in vivo use. This has the advantage that identical physiological conditions are present during SPF testing and application in the sun. Furthermore, the method according to the invention is non-invasive. In addition, the method takes into account the propagation of light in the skin, thereby achieving increased measurement accuracy.Taking physiological properties into account through a more realistic skin model leads to an improvement in the determination of the sun protection factor in the UVA and visible spectral ranges. Furthermore, it allows for the harmonization of in-vivo (human skin) and in-vitro tests. In addition, the method can be used for a very wide wavelength range, not limited by lamp spectra, erythema response spectrum, reactions of the measuring device, or similar factors.

[0027] In an alternative embodiment of the invention, the individual beam sources of the beam source device are controlled separately, i.e., different parameters and settings are defined for each individual beam source. These parameters include current, intensity (independent of current via PWM), and temperature. The individual beam sources of the measuring system also emit different wavelength spectra. This is preferably polychromatic light emitted from polychromatic light sources such as UV LEDs. The beam sources can be operated in pulsed mode. Furthermore, the beam sources can be controlled with respect to the intensity and wavelength range they emit. In a further embodiment of the invention, the beam sources are controlled dynamically. Therefore, adjustment of the detection is not necessary.This method filters out scattered light and fluorescence components of the radiation reflected by the sample and makes better use of the limited dynamics of the detection.

[0028] The method according to the invention also offers the possibility of extending the spectral range for measurement, since erythema is essentially only induced by UVB radiation, and this measurement range is of particular importance for determining the sun protection factor. Due to the low light dose irradiated onto the measuring body, no restrictions regarding the measurement location need to be observed. Even measurements on the sensitive scalp are possible. Furthermore, the influence of substances that cause skin reddening or UV-induced erythema on the measurement according to the invention is also avoided. The method according to the invention is simpler and more informative than previously known methods and is associated with lower costs.

[0029] In a further embodiment of the invention, a reference spectrum of a radiation source is recorded. The reference spectrum is determined using a standard sample in order to ascertain the wavelength range and intensity of the light emitted by the radiation source.

[0030] In a further embodiment of the invention, a central wavelength for a single beam source is determined from the reference spectrum of that beam source, thus defining a spectral detection window for that beam source. The reference spectrum is determined using a standard sample to ascertain the wavelength range and intensity of the light emitted by the beam source. Based on these data, a spectral detection window for the spectrometer is determined, through which the light emitted by the beam source is transparent.

[0031] In a further embodiment of the invention, a spectral window of a radiation source is determined and / or defined. In order to determine a wavelength range of the radiation sources depending on the requirements of the measurement, a spectral window of both the radiation source and the spectrometer is determined or defined.

[0032] In another aspect of the invention, the determination and / or the setting of a spectral window for the first and the second test spectrum is carried out separately.

[0033] In a further embodiment of the invention, the spectrum of a radiation source is mathematically filtered. For this purpose, the spectrum is superimposed, for example, with a trapezoidal function and / or another suitable filter function. This increases the signal-to-noise ratio.

[0034] In a further embodiment of the invention, the mathematical filtering of the spectrum of a radiation source is carried out such that the signal of a filtered spectrum outside the defined spectral window of the radiation source has a maximum filtered intensity of 15% of the maximum original intensity of the emitted signal within the defined spectral window. Preferably, the maximum filtered intensity is less than 10%, and particularly preferably less than 5% of the maximum original intensity. Alternatively or additionally, the signal of a filtered spectrum outside the defined spectral window of the radiation source can have a maximum peak intensity of 15% of the maximum original peak intensity of the emitted signal within the defined spectral window.

[0035] In a further development of the invention, the recording of a reference spectrum is carried out separately for each radiation source. Preferably, the process steps of determining the central wavelength of the reference spectrum of a radiation source and determining the mathematical filter of a radiation source are also carried out separately for each radiation source.

[0036] In a further embodiment of the invention, the method includes recording a first test spectrum of a radiation source. From the first test spectrum, the exposure time and / or the luminous intensity of the light emitted by the radiation source to be used for the measurement are determined.

[0037] In a further aspect of the invention, the first test spectrum is recorded from the irradiation of an untreated measuring body. The first test spectrum serves in particular to determine the exposure time and / or luminous intensity of the light emitted by the radiation source.

[0038] In a further embodiment of the invention, the method includes recording a second test spectrum of a radiation source. From the second test spectrum, the exposure time and / or the luminous intensity of the light emitted by the radiation source to be used for the measurement are determined.

[0039] In a further embodiment of the invention, the second test spectrum is recorded from the irradiation of a measuring body treated with a sunscreen. Like the first test spectrum, the second test spectrum serves in particular to determine the exposure time and / or luminous intensity of the light emitted by the radiation source.

[0040] In a further embodiment of the invention, the recording of the first and / or the second test spectra is carried out separately for each radiation source. This ensures that the intensity and wavelength range are known or defined for each radiation source and improves the signal-to-noise ratio.

[0041] In a further embodiment of the invention, a first measurement spectrum is recorded. Preferably, the parameters previously determined in the reference and / or test spectra, such as the central wavelength, the mathematical filter, the exposure time and / or the light intensity, are used for this purpose.

[0042] In a further development of the method according to the invention, the first measurement spectrum is recorded by irradiating an untreated measuring body.

[0043] In a further embodiment of the invention, a second measurement spectrum is recorded. Preferably, the parameters previously determined in the reference and / or test spectrum(s), such as the central wavelength, the mathematical filter, the exposure time, and / or the light intensity, are used for this purpose.

[0044] In a further development of the method according to the invention, the first measurement spectrum is recorded by irradiating a measuring body treated with a sunscreen.

[0045] In a further embodiment of the invention, a complete spectrum is composed from the measurement spectra of two or more radiation sources. Depending on the application, e.g., measuring a sun protection factor and / or determining fluorescence, the method according to the invention selectively chooses an emission spectrum and uses it for the measurement.

[0046] In a further embodiment of the invention, a first total spectrum is composed of filtered spectra from the first measurement spectra of two or more radiation sources and / or a second total spectrum is composed of filtered spectra from the second measurement spectra of two or more radiation sources.

[0047] In a further aspect of the invention, a measuring body is irradiated simultaneously with radiation of a complete spectrum from the first and the second radiation sources. For this purpose, a location on the inside of the forearm or the back of a test subject is typically targeted. This measurement location 3 is measured with the measuring system 1 by shining light onto it via an optical fiber. The irradiation is performed at an intensity that does not cause any acute damage to the skin.

[0048] Exemplary embodiments of the measuring system and the method according to the invention are shown schematically simplified in the drawings and are explained in more detail in the following description.

[0049] They show: Fig. 1: An embodiment of the measuring system according to the invention. Fig. 2: Another embodiment of the measuring system according to the invention. Fig. 3a: Top view of an embodiment of a beam source device with eight beam sources. Fig. 3b: View of an embodiment of a beam source device with eight beam sources along the beam direction. Fig. 4: The method according to the invention for determining sun protection factors. Fig. 5: Method for recording a reference spectrum. Fig. 6: Method for recording a test spectrum. Fig. 7: Method for recording a measurement spectrum. Fig. 8: Method for recording a reference, test, or measurement spectrum.

[0050] Fig. 1 Figure 1 schematically shows an embodiment of the measuring system 1 according to the invention. The measuring system 1 comprises a beam source assembly 12 with several beam sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8. The spectrum emitted by the beam source assembly 12 is introduced into the sample 3 by means of an optical fiber 4.1, and the light reflected from the sample 3 passes through another optical fiber 4.2 into the spectrometer 13. The spectrometer 13 and the beam source assembly 12 are connected via data lines 23, 24 to a beam source controller 11, which in turn is connected via another data line 21 to the externally arranged control unit 2. The beam source controller is designed to dynamically control the beam sources.

[0051] The control unit 2 is typically a PC or notebook computer with the appropriate computer program. Control unit 2 and spectrometer 13 are also connected to each other via a data line 22.

[0052] The procedure for determining sun protection factors 100 includes signal optimization of the radiation source device 12 prior to the actual measurement for determining a sun protection factor. This achieves a targeted adaptation of the spectrum of the radiation source device 12 to various measurement requirements. For this purpose, a reference spectrum of a radiation source 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 of the radiation source device 12 is recorded. From this reference spectrum, the central wavelength and its intensity (luminous flux) emitted by the radiation source 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 are determined. Furthermore, a spectral window is defined for the radiation source 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8. A test spectrum is then recorded on a measuring body 3 that is not treated with a sunscreen.The test spectrum is then mathematically filtered such that the portions outside the defined spectral window either have an intensity of 0 or, to maintain continuity in the composite spectrum, have an intensity that no longer significantly contributes to the result. A trapezoidal function or a Gaussian function with an exponent greater than 2 can be used for this purpose. This process (recording a reference spectrum, defining a spectral window, recording a test spectrum, filtering) is repeated for each radiation source 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 within the radiation source assembly 12. Finally, the partial spectra are sequentially illuminated onto the sample 3. A complete spectrum is then assembled from these measurement spectra, which is used to determine the sun protection factor.

[0053] A detailed view of an embodiment of the measuring system 1 according to the invention shows Fig. 2 The measuring system 1 comprises a beam source assembly 12 with five beam sources 12.1, 12.2, 12.3, 12.4, and 12.5. The beam sources 12.1, 12.2, 12.3, 12.4, and 12.5 are advantageously LEDs with a particularly long lifetime. The spectral ranges of the individual LEDs differ from one another such that a spectral range is covered, particularly in the UVA (315–380 nm) and UVB (280–315 nm) ranges. The light emitted by the beam sources 12.1, 12.2, 12.3, 12.4, and 12.5 is focused by a lens system 14, coupled into the light guide 4.1, and directed onto the sample 3. The light reflected from sample 3 passes through another optical fiber 4.2 and another lens system 15 into the spectrometer 13.Spectrometer 13 and beam source device 12 are connected via the data line 24 to the beam source control 11, which in turn is connected via another data line to the externally arranged control device 2 (not shown, see . Fig. 1 The beam source control 11 controls the intensity and wavelengths of the beam source device 12 and receives the data from the spectrometer 13 for this purpose.

[0054] The procedure for determining sun protection factors 100 includes, prior to the actual measurement for determining a sun protection factor, a signal optimization of the radiation source device 12.

[0055] For this purpose, a reference spectrum of a radiation source 12.1, 12.2, 12.3, 12.4, 12.5 of the radiation source assembly 12 is recorded. From this reference spectrum, the central wavelength and its intensity (luminous flux) emitted by the radiation source 12.1, 12.2, 12.3, 12.4, 12.5 are determined. A spectral window for the radiation source 12.1, 12.2, 12.3, 12.4, 12.5 is also defined. Subsequently, a test spectrum is recorded on a sample 3 that is not treated with a sunscreen. The test spectrum is then mathematically filtered such that the test spectrum outside the defined spectral window has an intensity of 0 or, to maintain continuity in the composite spectrum, has an intensity that no longer contributes significantly to the result. For this purpose, a trapezoidal function or a Gaussian function with an exponent greater than 2 can be used.This described process (recording a reference spectrum, defining a spectral window, recording a test spectrum, filtering) is repeated for each radiation source 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 within the radiation source assembly 12. Finally, the measurement spectra are recorded by irradiating the partial spectra sequentially onto the sample 3. A complete spectrum is then assembled from these measurement spectra, which is used to determine the sun protection factor.

[0056] Fig. 3 Figure 1 shows an embodiment of an arrangement of the beam sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 and the lens system 14 in the beam source device 12 for coupling the light emitted by the beam sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 into a light guide 4.1 ( Fig. 3 a) .

[0057] The beam source device 12 has eight beam sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8, preferably LEDs, which are arranged in a circle ( Fig. 3 b) . Each beam source 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 can be individually controlled by means of the beam source control 11, i.e. individual beam sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 can be activated or deactivated, or several beam sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 can be used sequentially for illumination, which enables the investigation of wavelength-dependent effects (e.g. fluorescence detection).

[0058] To focus the light generated by the light sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8, a lens 14.1, 14.2, 14.3, 14.4, 14.5 is arranged in front of each light source 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8, which shines the light generated by the light sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 into the lens 14.9. The lens 14.9 focuses the light generated by the beam sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 onto a light guide 4.1 and couples the light into it.

[0059] The procedure for determining sun protection factors includes, prior to the actual measurement for determining a sun protection factor, a signal optimization of the radiation source device 12.

[0060] For this purpose, a reference spectrum of a radiation source 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 of the radiation source device 12 is recorded. From this reference spectrum, the central wavelength and its intensity (luminous flux) emitted by the radiation source 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 are determined. A spectral window for the radiation source 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 is also defined. Subsequently, a first and / or second test spectrum is recorded on a measuring body 3 that is not treated with a sunscreen. The test spectrum is then mathematically filtered such that the test spectrum outside the defined spectral window has an intensity of 0, or, to comply with continuity conditions in the composite spectrum, has an intensity that no longer contributes significantly to the result.For this purpose, a trapezoidal function or a Gaussian function with an exponent greater than or equal to 2 can be used.

[0061] This described process (recording a reference spectrum, defining a spectral window, recording a test spectrum, filtering) is repeated for each radiation source 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 within the radiation source assembly 12. Finally, the partial spectra are irradiated one after the other onto the sample 3, and a complete spectrum is then assembled from the measured spectra, which is used to determine the sun protection factor.

[0062] The inventive method 100 for determining sun protection factors shows Fig. 4 At the beginning of the procedure 100, a reference measurement 110 is performed. The reference measurement 110 comprises the recording of one or more reference spectra 111 to determine the spectral windows of the radiation sources 12. From this reference spectrum, the central wavelength 112 is determined, and a mathematical filter 113 is determined to establish the spectral detection window (wavelength range) for each radiation source. In a second procedure step, the test measurement 120 is performed. The test measurement 120 comprises the recording of one or more test spectra 121. From the test spectra, the exposure time and / or the luminous intensity of the individual radiation sources 12 are determined 122. Subsequently, the sample measurements 130 are carried out. In the fourth procedure step, the partial spectra resulting from the sample measurements are combined to form a complete spectrum 140.The light protection factor of the radiation protection agent is then determined from the total spectra: 150.

[0063] In one embodiment, the partial steps of the method according to the invention are carrying out the reference measurement 110, carrying out the test measurement 120 and carrying out the sample measurement 130 in the Fig. 5 - 7 depicted.

[0064] During the reference measurement, a reference measurement is performed on a standard sample for a first radiation source 111. A central wavelength is first determined for the first radiation source 112. In a subsequent step, a mathematical filter is then defined 113. This procedure is repeated for all radiation sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 114. The mathematical filter 114 is determined by a software program running on the control unit 2. The mathematical filtering is performed such that the measured reference spectrum outside the defined spectral window has a maximum filtered intensity of 15% of the maximum original intensity of the signal within the defined spectral detection window, or, to maintain continuity conditions in the composite spectrum, has an intensity that no longer contributes significantly to the result.For this purpose, a trapezoidal function or a Gaussian function with an exponent greater than or equal to 2 can be used. Alternatively, the reference measurement 110 can first be carried out for each individual radiation source 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8. Subsequently, the central wavelength of each radiation source 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 and the mathematical filtering are determined.

[0065] The test measurement 120 (see Fig. 6 For each radiation source 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8, a test spectrum 121 is recorded for each radiation source 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8, using both an untreated and a radiation-shielded sample. The exposure time is chosen to be very short in order to keep the radiation dose as low as possible. It serves to determine the optimal exposure time and the optimal power dose and comprises the following procedural steps: recording a test spectrum 121, determining the exposure time and / or the light power 122, and repeating the two aforementioned procedural steps for each radiation source 123. For a complete test measurement, a complete cycle is performed for each radiation source 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8.For test measurement 120, the mathematical filters for the individual radiation sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8, or the defined spectral detection windows, previously determined in reference measurement 110, are already used. Alternatively, test measurements 121 can first be carried out for several or all radiation sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8. The exposure time and / or the light intensity is then subsequently determined for each radiation source 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8. Following this, a query 124 is performed to determine whether the respective recording of the test spectrum 121 has been carried out to determine the exposure time 122 for all intended light sources 123 for both an untreated and a treated measuring body 3.

[0066] Sample measurement 130 (see Fig. 7 ) is carried out using the central wavelength, filters and / or spectral windows of the individual radiation sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 determined in the reference measurement 110. Furthermore, the exposure time and / or the light power determined in the test measurement 120 for the individual radiation sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 are used in the sample measurements 130. The sample measurement 130 involves recording sample spectra 131 from several radiation sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 of an untreated and a radiation-treated measuring body 3. Sample spectra from both measuring bodies 3 are recorded separately for each of the radiation sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 used. The sample spectra of the individual radiation sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 are then recorded.8 are then combined to obtain the total spectra for the sample measurements on the untreated and the treated measuring body 140. From the total spectrum of the measurements on the untreated measuring body 3 and the total spectrum of the measurements on the measuring body 3 treated with a radiation protection agent, the protection factor of the radiation protection agent used is then determined 150.

[0067] The following are alternatives to performing the reference measurement 110, the test measurement 120 and the sample measurement 130.

[0068] After performing a reference measurement 110 and a test measurement 120, a measurement spectrum is recorded 131 from a measuring body 3 that is not treated with sunscreen using a single radiation source 12.1. The measurement spectrum is then mathematically filtered 132 by a corresponding software program on the control device 2, preferably by superimposing it with a trapezoidal function and / or another suitable filter function. The filtered measurement spectrum is filtered such that, outside the defined spectral detection window (see process step 120), it has a maximum filtered intensity of 15% of the maximum original intensity of the signal within the defined spectral detection window. In alternative embodiments, the maximum filtered intensity is 10% or 5% of the maximum original intensity of the signal within the defined spectral detection window.

[0069] Additionally, after recording 131 and filtering 132 a measurement spectrum of a sample body 3 untreated with sunscreen from a radiation source 12.1, a measurement spectrum of the same radiation source 12.1 of a sample body 3 treated with sunscreen can be recorded. Due to these process steps 131, 132, both the natural protection of the subject's skin and the influence of an applied sunscreen are taken into account during the actual determination of the sun protection factor. This allows, in particular, a reduction in the exposure time during the determination of the sun protection factor 150, as a higher intensity of the spectrum irradiated onto the sample 3 can be selected for high sun protection factors than for low sun protection factors, without damaging the subject's skin. Furthermore, the targeted activation of one or more radiation sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 enables the investigation of wavelength-dependent effects, e.g.Fluorescence detection is possible.

[0070] In the next process step 133, a query is performed to determine whether each of the radiation sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 installed in the radiation source assembly 12 has undergone sample measurement 130 (acquisition of the measurement spectrum and filtering). If this is not the case, sample measurement 130 is repeated for another radiation source 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 until each radiation source 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 has undergone procedure 130. This is followed by a query 133 to determine whether the respective recording of the measurement spectrum 131 and the filtering for all intended light sources 123 has been carried out, and a query 134 to determine whether the recording of a measurement spectrum 131 and the filtering of the measurement spectrum 132 has been carried out for both an untreated and a treated measuring body 3.

[0071] In the next process step 140, an overall spectrum is composed from the individual emission spectra of the individual radiation sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8, which in the next process step 150 is irradiated onto the sample 3 and a sun protection factor is determined.

[0072] For this purpose, a location on the inner forearm or back of a subject 3 is typically selected. This measurement site 3 is measured using the measurement system 1 by shining light onto a defined area with a diameter of approximately 500 µm – generated, for example, by placing an optical fiber 4.1 (illumination fiber) with a core diameter of 500 µm on the area. Smaller core diameters of, for example, 200 µm, 100 µm, or 50 µm are also possible. The irradiation is applied at an intensity that does not cause acute damage to the skin, which is below the simple MED, below the MZB values, or significantly below the values ​​caused by sunlight. 1 MED corresponds to the lowest irradiation dose that, when read after 24 hours, caused a sharply defined erythema (redness) of the skin.

[0073] This light passes through the subject's skin and emerges at a distance from a detection surface, which in turn consists of an attached optical fiber.

[0074] To increase sensitivity or further reduce the illumination intensity, several detection fibers 4.1, 4.2 can be arranged at the same or at least similar distances from the edge of the illumination fiber in an optical measuring head that is in direct contact with the measurement point 3. These fibers are then guided together onto a detection device, and the intensity is measured. Depending on the intensity level and the selected detector 13, the signal generated by the radiation is amplified by a defined factor, which also provides a signal above the noise level for the subsequent measurement of the lower intensity. Detection is wavelength-resolved. The resolution can be, for example, 1 nm and is selected depending on the definition of the light protection factor.

[0075] Furthermore, it is conceivable to repeat individual measurements during a measurement cycle, whereby the individual measurements are averaged or accumulated. In addition, several measurements can be performed periodically, for example every 5 seconds, and analyzed until the deviation of the successive values ​​is below the simple standard deviation, i.e., until stable values ​​are reached. Such an evaluation takes place in the control unit 2, which ends the measurement when stable values ​​are reached and signals this to a user.

[0076] In a variation of one of the above embodiments, a further measurement is to be carried out at a different measuring location 3 in the same manner. This allows the light protection factor of the same radiation protection agent with the same application to be compared at different measuring locations 3.

[0077] In Fig. 8The procedure for recording spectra 200 is shown. First, a radiation source 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 or a group of radiation sources 12 is activated 210. Then, the actual recording of the spectrum 220 takes place. Following this, the radiation source 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 or a group of radiation sources 12 is deactivated again 230. Finally, a check is performed to see if the spectra have already been recorded for all radiation sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8. If this is the case, the recording of spectra for this cycle is complete. If this is not the case, the loop continues until a spectrum has been recorded for all radiation sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8. REFERENCE MARK LIST

[0078] 1 Measuring system 2 Control unit 3 Sample / Measuring body 4.1, 4.2 Optical fiber / Fiber bundle 11 Beam source control 12 Beam source unit 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 Beam source / LED 13 Detector / Spectrometer 14 Lens system 14.1, 14.2, 14.3, 14.4, 14.5, 14.9 Lens 15 Lens 21 Connection Beam source control - Beam source unit 22 Connection Detector / Spectrometer - Control unit 23 Connection Beam source control - Control unit 24 Connection Beam source control - Detector / Spectrometer 100 Method for determining sun protection factors 110 Reference measurement 111 Recording a reference spectrum 112 Determination of the central wavelength and the filter wavelengths 113Determination of the mathematical filter 114Query whether reference measurement has been carried out for all radiation sources 120Test measurement 121Recording of a test spectrum 122Determination of the exposure time and / or the light intensity 123Query,124 Check whether test measurement has been performed for all radiation sources 130 Sample measurement 131 Recording of a measurement spectrum 132 Mathematical filtering of the measurement spectrum 133 Check whether test measurement has been performed for all radiation sources 134 Check whether test measurement has been performed on treated and untreated measuring bodies 140 Composing a complete spectrum from the partial spectra of the radiation sources 150 Calculation of the sun protection factor 200 Recording of a spectrum 210 Activating a radiation source or a group of radiation sources 220 Acquiring a spectrum 230 Deactivating a radiation source or a group of radiation sources 240 Checking whether a spectrum has been recorded for each radiation source

Claims

1. A measurement system (1) for determining the sun protection factors of sunscreens, comprising the following components - a radiation source device (12) wherein the radiation source device (12) comprises two or more separate radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8), - a spectrometer (13) - a control device (2) wherein the wavelength spectra of the beams emitted by at least two of the separate beam sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) are different, and the individual beam sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) of the beam source device (12) can be controlled separately, pulsed, and regulated, wherein the beam sources can be dynamically controlled, wherein parameters of the radiation sources can be dynamically adjusted during a measurement sequence based on measurement data.

2. Measurement system (1) for determining sun protection factors of sunscreens according to claim 1 characterized in that the spectrometer (13) is controllable by the control device (2) and / or the signals measured by the spectrometer (13) are processable by the control device (2).

3. Measuring system (1) for determining sun protection factors of sunscreens according to one or more of the preceding claims characterized in that the measuring system (1) comprises a radiation source controller (11) that is suitable for controlling the radiation source device (12), wherein the radiation source controller (11) is suitable and designed to control the individual radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) of the radiation source device (12) separately.

4. Measuring system (1) for determining sun protection factors of sunscreens according to claim 3 characterized in that the wavelength, the exposure time, and / or the intensity of the radiation emitted by the individual radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) can be controlled separately by means of the radiation source controller (11).

5. A measurement system (1) for determining sun protection factors of sunscreens according to claim 3 or 4 characterized in that the radiation source control unit (11) is arranged separately from the control device (2).

6. Measuring system (1) for determining sun protection factors of sunscreens according to one or more of claims 3 through 5 characterized in that the radiation source controller (11) is controllable by the control device (2).

7. A measurement system (1) for determining sun protection factors of sunscreens according to one or more of claims 3 through 6 characterized in that the radiation source controller (11) is connected to the spectrometer (13) and is suitable and designed to receive signals from the spectrometer (13) and / or to send control commands to the spectrometer (13).

8. A method (100) for determining sun protection factors of sunscreens using a spectroscopic measurement, comprising the following method steps: - controlling a first radiation source (12.1) of a radiation source device (12) comprising a plurality of radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8), - controlling a second radiation source (12.2) of a radiation source device (12) comprising a plurality of radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8), - irradiating a test specimen (3) with radiation of a combined spectrum from the first and second radiation sources (12.1, 12.2), wherein the control command for the first radiation source (12.1) differs from the control command for the second radiation source (12.2), and the individual radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) of the radiation source assembly (12) can be controlled separately, pulsed, and regulated, wherein the beam sources can be dynamically controlled wherein parameters of the light sources can be dynamically adjusted during a measurement sequence based on measurement data.

9. A method (100) for determining sun protection factors of sunscreens using a spectroscopic measurement according to claim 8 characterized in that the method (100) comprises recording (110) a reference spectrum of a radiation source (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8), wherein a central wavelength of the single light source (12.1) and a spectral detection window for the single light source (12.1) are determined (120) from the reference spectrum of the single light source (12.1).

10. Method (100) for determining sun protection factors of sunscreens using a spectroscopic measurement according to claim 8 or 9 characterized in that the method (100) comprises recording (130) a first test spectrum of a radiation source (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8), wherein the first test spectrum is recorded (130) by irradiating an untreated test specimen (3).

11. A method (100) for determining sun protection factors of sunscreens using a spectroscopic measurement according to one or more of claims 8 through 10 characterized in that the method (100) comprises recording a second test spectrum from a radiation source (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8), wherein the second test spectrum is recorded from the irradiation of a test specimen (3) treated with a sunscreen product.

12. Method (100) for determining sun protection factors of sunscreens using a spectroscopic measurement according to one or more of claims 8 through 11 characterized in that the method (100) comprises mathematically filtering (140) the remission spectrum (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) measured with a radiation source, wherein the mathematical filtering (140) of the spectrum of a radiation source (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) is performed such that the signal of a filtered spectrum outside the specified spectral window of the beam source (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) has a filtered maximum intensity of 15% of the maximum original intensity of the signal within the specified spectral window.

13. A method (100) for determining sun protection factors of sunscreens using a spectroscopic measurement according to one or more of claims 8 through 12 characterized in that one or more of the method steps (110, 120, 130, 140) according to claims 9 through 13 are performed separately for each radiation source (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8).

14. A method (100) for determining sun protection factors of sunscreens using a spectroscopic measurement according to one or more of claims 8 through 13 characterized in that the method (100) comprises combining (200) a composite spectrum from the filtered spectra of two or more radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8), wherein the method (100) comprises combining (200) a first composite spectrum from filtered spectra derived from the first measurement spectra of two or more radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) and / or combining (200) a second composite spectrum from filtered spectra derived from the second measurement spectra of two or more radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8).