MEASURING SYSTEM AND MEASURING METHOD

Abstract

The invention describes a method for determining sun protection factors of sunscreen agents with a spectroscopic measurement comprising the following steps: first activation of several radiation sources of a radiation source device having at least two radiation sources, first emission of radiation from the at least two radiation sources, detection of the radiation diffusely reflected by a measuring body, determination of the sensor sensitivity S.sub.T of a detector, determining the target exposure time t.sub.Z and/or the target light power l.sub.Z for the at least two radiation sources, second driving of a plurality of radiation sources of the radiation source device having at least two radiation sources, second emission of radiation from the at least two radiation sources with a target exposure time t.sub.Z and/or the target light power l.sub.Z of the first and the second radiation source of the radiation source device.

Claims

1. Method for determining sun protection factors of sunscreen agents (100) with a spectroscopic measurement with the method steps: First actuation of several radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) of a radiation source device comprising at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) First emission of radiation from the at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) Detection of the radiation remitted/reflected by a measuring body Determination of the sensor sensitivity S.sub.T of a detector Determining the target exposure time t.sub.Z and/or the target light power l.sub.Z for the at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) Second actuation of several radiation sources of the radiation source device comprising at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) Second emission of radiation from the at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) with a target exposure time t.sub.Z and/or the target light power l.sub.Z of the first and the second radiation source (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) of the radiation source device.

2. Method for determining sun protection factors of sunscreen agents (100) with a spectroscopic measurement according to claim 1 characterised in that the exposure time t.sub.T of the first emission of radiation from the at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) is less than 0.5 s and/or the light output l.sub.T of the first emission from the at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) is greater than l.sub.T>0.8*l.sub.max with l.sub.max as the maximum light output of the at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8).

3. Method for determining sun protection factors of sunscreen agents (100) with a spectroscopic measurement according to claim 1, characterised in that the exposure time t.sub.T of the first emission of radiation is smaller than the target exposure time t.sub.Z of the second emission of radiation from the at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8).

4. Method for determining sun protection factors of sunscreen agents (100) with a spectroscopic measurement according to claim 1, characterised in that the target exposure time t.sub.Z is determined from the sensor sensitivity S.sub.T of the first emission of radiation from the at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8).

5. Method for determining sun protection factors of sunscreen agents (100) with a spectroscopic measurement according to claim 4 characterised in that the target exposure time t.sub.Z from the sensor control S.sub.T of the first emission of radiation from the at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) from the relation
t.sub.Z=S.sub.Z/S.sub.T*t.sub.T is determined with S.sub.Z as the target sensor sensitivity.

6. Method for determining sun protection factors of sunscreen agents (100) with a spectroscopic measurement according to claim 4, characterised in that the target sensor sensitivity S.sub.Z in a range
0.3*IR.sub.max<S.sub.Z<IR.sub.max with IR.sub.max as the maximum pulse rate of the sensor.

7. Method for determining sun protection factors of sunscreen agents (100) with a spectroscopic measurement according to claim 1, characterised in that the first emission of radiation from the at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) onto a measuring body is of the same type as the second emission of radiation from the at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8).

8. Method for determining sun protection factors of sunscreen agents (100) with a spectroscopic measurement according to claim 1, characterised in that the first emission of radiation from the at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) takes place on the same measuring body as the second emission of radiation from the at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8).

9. Method for determining sun protection factors of sunscreen agents (100) with a spectroscopic measurement according to claim 8 characterised in that the first emission of radiation from the at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) occurs at the same measuring position of the measuring body as the second emission of radiation from the at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8).

10. Method for determining sun protection factors of sunscreen agents (100) with a spectroscopic measurement according to claim 1, characterised in that the target exposure time t.sub.Z1 and/or the target light power l.sub.Z1 of the first radiation source (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) is different from the target exposure time t.sub.Z2 and/or the target light power l.sub.Z2 of the second radiation source (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8).

11. Method for determining sun protection factors of sunscreen agents (100) with a spectroscopic measurement according to claim 1, characterised in that the first emission of radiation from the at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) is performed separately for the at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8).

12. Method for determining sun protection factors of sunscreen agents (100) with a spectroscopic measurement according to claim 11 characterised in that the first emission of radiation from the at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) is performed separately for each radiation source.

13. Method for determining sun protection factors of sunscreen agents (100) with a spectroscopic measurement according to claim 11, characterised in that the first emission of radiation from the at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) takes place in groups of radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) with similar maximum light output.

14. Method for determining sun protection factors of sunscreen agents (100) with a spectroscopic measurement according to claim 1, characterised in that the second emission of radiation from the at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) is performed separately for the at least two radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8).

15. Method for determining sun protection factors of sunscreen agents (100) with a spectroscopic measurement according to claim 14 characterised in that the second emission of radiation from the at least two radiation sources (12.1, 12.2, 15 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) is performed separately for each radiation source (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8).

16. Method for determining sun protection factors of sunscreen agents (100) with a spectroscopic measurement according to claim 14 characterised in that the second emission of radiation from the at least two radiation sources takes place in groups of radiation sources with similar maximum light output.

17. Method for determining sun protection factors of sunscreen agents (100) with a spectroscopic measurement according to claim 1, characterised in that the radiation is generated by the radiation source.

18. Method for determining sun protection factors of sunscreen agents (100) with a spectroscopic measurement according to claim 17 characterised in that after the radiation is generated by the radiation source, the generated radiation is emitted by the radiation source.

19. Method for determining sun protection factors of sunscreen agents (100) with a spectroscopic measurement according to claim 17 characterised in that the radiation generated and emitted by the radiation source is conditioned and guided by means of devices for conditioning and/or guiding the radiation.

20. Measuring system (1) for determining sun protection factors of sunscreen agents, which has 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) characterised in that the at least two separate radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) can be controlled separately.

21. Measuring system (1) for determining sun protection factors of sunscreen agents, according to claim 20 characterised in that the wavelength spectra of the ray emitted by at least two of the separate radiation sources (12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8) are different.

22. Measuring system (1) for determining sun protection factors of sunscreen agents according to claim 20 characterised in that the spectrometer (13) can be controlled by the control device (2) and/or the signals measured by the spectrometer (13) can be processed by the control device (2).

23. Measuring system (1) for determining sun protection factors of sunscreen agents according to claim 20 characterised in that 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) are separately controllable.

24. Measuring system (1) for determining sun protection factors of sunscreen agents according to claim 20 characterised in that the measuring system (1) has a radiation source control (11) which is suitable for controlling the radiation source device (12).

25. Measuring system (1) for determining sun protection factors of sunscreen agents according to claim 24 characterised in that the radiation source control (11) is suitable and intended for separately controlling 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).

26. Measuring system (1) for determining sun protection factors of sunscreen agents according to claim 24 characterised in that by means of the radiation source control (11), the wavelength 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.

27. Measuring system (1) for determining sun protection factors of sunscreen agents according to claim 24 characterised in that the radiation source control (11) is arranged separately from the control device (2).

28. Measuring system for determining sun protection factors of sunscreen agents according to claim 24 characterised in that the radiation source control (11) can be controlled by the control device (2).

29. Measuring system (1) for determining sun protection factors of sunscreen agents according to claim 24 characterised in that the radiation source controller (11) is connected to the spectrometer (13) and is suitable and intended to receive signals from the spectrometer (13) and/or to send control commands to the spectrometer (13).

30. Measuring system (1) for determining sun protection factors of sunscreen agents according to claim 20 characterised in that the radiation sources are intended and suitable for producing radiation.

31. Measuring system (1) for determining sun protection factors of sunscreen agents according to claim 30 characterised in that the radiation sources are intended and suitable for emitting the radiation produced by the radiation sources themselves.

32. Measuring system (1) for determining sun protection factors of sunscreen agents according to claim 30 characterised in that the measuring system (1) has one or more devices for conditioning and/or guiding the radiation.

Description

[0047] Showing:

[0048] FIG. 1: General procedure for determining the optimal exposure time of the individual radiation sources

[0049] FIG. 2: Alternative procedure for determining the optimal exposure time of the individual radiation sources

[0050] FIG. 3: Procedure with the grouping of radiation sources for the determination of sun protection factors

[0051] FIG. 4: Procedure for activating the individual radiation sources

[0052] FIG. 5: Procedure for carrying out a measurement to determine sun protection factors

[0053] FIG. 6: Measuring system for determining sun protection factors.

[0054] FIG. 7: Radiation source device for determining sun protection factors.

[0055] FIG. 1 schematically shows an embodiment example of the method 120 according to the invention, in which a test measurement 121 is carried out for each individual radiation source and then a measurement is carried out to determine a sun protection factor.

[0056] At the beginning of the procedure 120, a test spectrum of a single radiation source 12.1, 12.2, 12.3, 12.4, 12.5 is recorded 121. For this purpose, the individual radiation source e.g. 12.1 is controlled by means of the radiation source control 11 (see FIG. 6, 7) in such a way that the radiation source 12.1 emits radiation. The exposure time t.sub.T of the test measurement 121 is selected so that the exposure time t.sub.T of the radiation is 0.5 s. The light output l.sub.T is l.sub.T>0.8*l.sub.max with l.sub.max as the maximum light output. Based on these parameters, the spectrometer 13 has a sensor sensitivity S.sub.T.

[0057] Then the target exposure time t.sub.Z and the light power 122 for the actual sample measurement 131 are determined for the controlled radiation source 12.1. The target exposure time t.sub.Z and the target sensor sensitivity S.sub.Z are calculated from the sensor sensitivity S.sub.T of the spectrometer 13. The relationship between the target exposure time t.sub.Z and the target sensor sensitivity S.sub.Z is valid. The following relationship applies t.sub.Z=S.sub.Z/S.sub.T*t.sub.T. It has also been found that a good signal-to-noise ratio of the spectrometer 13 is obtained when the target sensor sensitivity S.sub.Z is in the range between 0.3 times the maximum pulse rate of the spectrometer 13 and its maximum pulse rate. This choice of parameters reduces both the time required for the test measurement 121, for the actual measurement to determine the sun protection factor 131 and the radiation exposure for the test person.

[0058] In the next step of the procedure, a query is made as to whether a test spectrum 121 has been recorded for each of the individual radiation sources 12.1, 12.2, 12.3, 12.4, 12.5. If this is not the case, the method 120 starts again with the recording of a test spectrum 121 of a further individual radiation source 12.2. If this is the case, i.e. if a test spectrum is available for each radiation source 12.1, 12.2, 12.3, 12.4, 12.5, a measurement spectrum 131 is recorded by means of an individual radiation source 12.1. For this purpose, the individual radiation source 12.1 is again controlled by means of the radiation source control 11 in such a way that the radiation source 12.1 emits radiation with the parameters for exposure time t.sub.Z and light power l.sub.T determined in the process step 122. This measurement spectrum is then mathematically filtered by a corresponding software program on the control device 2 (see FIG. 6, 7), preferably by superimposing a trapezoidal function and/or a suitable other filter function on the measurement spectrum.

[0059] In the next process step, a query 133 is made as to whether the recording of a measurement spectrum 131 for each of the individual radiation sources 12.1, 12.2, 12.3, 12.4, 12.5 has taken place. If this is not the case, the method 120 starts again with the recording of a measurement spectrum 131 of a further individual radiation source 12.2. If this is the case, i.e. if a measurement spectrum is available for each radiation source 12.1, 12.2, 12.3, 12.4, 12.5, a query 134 is made as to whether the recording of the test spectra 121 and the recording of the measurement spectra 131 was carried out on a sample 3 untreated with sunscreen or on a sample 3 treated with sunscreen. If the recording of the test spectra 121 and the recording of the measurement spectra 131 was performed on a sample 3 untreated with sunscreen, the procedure 120 is performed on a sample 3 treated with sunscreen as described. The sun protection factor is then calculated from the measurement spectra of the sample 3 treated with sunscreen.

[0060] The procedure 120 presented here is therefore carried out at the same location on the measurement sample 3, in particular on the skin of a test person. In this way, the reproducibility of the selected parameters of light power and exposure time is guaranteed. The procedure 120 is first performed on a sample 3 untreated with sunscreen and then a second time on a sample 3 treated with sunscreen. Depending on the number of radiation sources 12.1, 12.2, 12.3, 12.4, 12.5 arranged in the radiation source device 12, the procedure requires a time of a few to a few 10 s.

[0061] Before starting the method according to the invention for determining a sun protection factor 100, a reference spectrum of each radiation source 12.1 of the radiation source device 12 is usually recorded. The reference spectrum is recorded by means of a standard sample body 3 and serves to determine the wavelength spectrum of each radiation source 12.1, 12.2, 12.3, 12.4, 12.5 and its intensity distribution. Advantageously, the reference spectrum is recorded for each measurement to calculate the sun protection factor in order to detect any intensity changes and changes in the wavelength spectrum due to, for example, ageing of the individual radiation sources 12.1, 12.2, 12.3, 12.4, 12.5.

[0062] A possible variant of the previous embodiment of the method 120 according to the invention is shown in FIG. 2. At the beginning of the method 120, a test spectrum of a single radiation source 12.1, 12.2, 12.3, 12.4, 12.5 is recorded 121. For this purpose, the individual radiation source 12.1 is controlled by means of the radiation source control 11 (see FIG. 6, 7) in such a way that the radiation source 12.1 emits radiation. Then the exposure time and the light power 122 for the controlled radiation source 12.1 are determined. In the next process step, a measurement spectrum 131 is recorded by means of a single radiation source 12.1. In the next process step, the recorded measurement spectrum 131 is mathematically filtered 132 by a corresponding software program on the control device 2 (see FIG. 6, 7).

[0063] In the next process step, a query 133 is made as to whether a test spectrum 121 and a measurement spectrum 131 have been recorded for each of the individual radiation sources 12.1, 12.2, 12.3, 12.4, 12.5. If this is not the case, the method 120 starts again with the recording of a test spectrum 121 of a further individual radiation source 12.2. If this is the case, i.e. if a test spectrum is available for each radiation source 12.1, 12.2, 12.3, 12.4, 12.5, a query 134 is made as to whether the recording of the test spectra 121 and the recording of the measurement spectra 131 was carried out on a sample 3 untreated with sunscreen or on a sample 3 treated with sunscreen. If the recording of the test spectra 121 and the recording of the measurement spectra 131 was carried out on a sample 3 untreated with sunscreen, the procedure 120 is carried out on a sample 3 treated with sunscreen as described.

[0064] The procedure 120 presented here is also carried out like the previous embodiment example on the same location of the measurement sample 3, in particular on the skin of a test person. The procedure 120 is first carried out on a sample 3 untreated with sunscreen and then a second time on a sample 3 treated with sunscreen. Due to the lack of a separate query as to whether a test spectrum has been recorded for all radiation sources arranged in the radiation source device 12 (see FIG. 1, item 123), the measurement time for determining a sun protection factor can be shorter compared to the previous embodiment example.

[0065] FIG. 3 shows an embodiment example of the method 120 according to the invention, in which the radiation sources 12.1, 12.2, 12.3, 12.4, 12.5 are divided into groups. The radiation sources 12.1, 12.2, 12.3, 12.4, 12.5 arranged in the radiation source device 12 are first divided into radiation source groups 12.1, 12.2, 12.3, 12.4, 12.5 125. Then, by means of the radiation source control 11 (see FIG. 6,7), an individual radiation source group 12.1 is controlled in such a way that the radiation source group 12.1 emits radiation 126. Then the exposure time and the light power 127 are determined for the controlled radiation source group 12.1. In the next process step, a measurement spectrum 135 is recorded by means of the individual radiation source group 12.1. In the next process step, the recorded measurement spectrum 135 is mathematically filtered 136 by a corresponding software program on the control device 2 (see FIG. 6, 7).

[0066] In the next process step, a query 137 is made as to whether a test spectrum 126 and a measurement spectrum 135 have been recorded for each of the individual radiation source groups 12.1, 12.2, 12.3, 12.4, 12.5. If this is not the case, the method 120 starts again with the recording of a test spectrum 126 of a further individual radiation source group 12.2. If this is the case, i.e. if a test spectrum is available for each radiation source group 12.1, 12.2, 12.3, 12.4, 12.5, a query 134 is made as to whether the recording of the test spectra 126 and the recording of the measurement spectra 135 was carried out on a sample 3 untreated with sunscreen or on a sample 3 treated with sunscreen. If the recording of the test spectra 121 and the recording of the measurement spectra 131 was carried out on a sample 3 untreated with sunscreen, the procedure 120 is carried out on a sample 3 treated with sunscreen as described.

[0067] By a radiation source group 12.1, 12.2, 12.3, 12.4, 12.5 it is understood in the context of this writing that a radiation source group 12.1, 12.2, 12.3, 12.4, 12.5 comprises at least one radiation source 12.1, 12.2, 12.3, 12.4, 12.5, but one of the radiation source groups 12.1, 12.2, 12.3, 12.4, 12.5 arranged in the radiation source device 12 has at least two radiation sources 12.1, 12.2, 12.3, 12.4, 12.5. Advantageously, radiation sources 12.1, 12.2, 12.3, 12.4, 12.5 with similar maximum light output are arranged in a radiation source group 12.1, 12.2, 12.3, 12.4, 12.5.

[0068] The procedure 120 presented here is also carried out like the previous embodiment examples on the same location of the measurement sample 3, in particular on the skin of a test person. The procedure 120 is first carried out on a sample 3 untreated with sunscreen and then a second time on a sample 3 treated with sunscreen.

[0069] A general embodiment of the method for recording a spectrum 200 is shown in FIG. 4. The method 200 shown here is used for recording reference spectra as well as for recording test spectra and for recording measurement spectra. In the first process step 210, a radiation source 12.1, 12.2, 12.3, 12.4, 12.5 of the radiation source device 12 or a radiation source group 12.1, 12.2, 12.3, 12.4, 12.5 is controlled and activated. In the next process step 220, a spectrum of the radiation source 12.1, 12.2, 12.3, 12.4, 12.5 activated in the first process step 210 or of the activated radiation source group 12.1, 12.2, 12.3, 12.4, 12.5 is detected. Thereafter, the radiation source 12.1, 12.2, 12.3, 12.4, 12.5 of the radiation source device 12 activated in the first method step 210 or the activated radiation source group 12.1, 12.2, 12.3, 12.4, 12.5 is deactivated 230. In the next method step 240, a query is made as to whether a spectrum has been acquired for each of the radiation sources 12.1, 12.2, 12.3, 12.4, 12.5 of the radiation source device 12. If this is the case, i.e. a spectrum is detected for each radiation source 12.1, 12.2, 12.3, 12.4, 12.5 of the radiation source device 12, the method 200 is terminated. If this is not the case, i.e. a spectrum has not yet been detected for each radiation source 12.1, 12.2, 12.3, 12.4, 12.5 of the radiation source device 12, the method 200 is repeated, starting with the first method step 210, until in method step 240 the query is answered to the effect that a spectrum has been detected for each radiation source 12.1, 12.2, 12.3, 12.4, 12.5 of the radiation source device 12.

[0070] FIG. 5 shows an example of an embodiment of the method according to the invention for determining sun protection factors 100. At the beginning of the method according to the invention for determining a sun protection factor 100, a reference spectrum of each radiation source 12.1, 12.2, 12.3, 12.4, 12.5 of the radiation source device 12 is usually recorded 110. The recording of the reference spectrum is usually carried out by means of a standard sample body 3 and serves to determine the wavelength spectrum of each radiation source 12.1, 12.2, 12.3, 12.4, 12.5 and its intensity distribution. Advantageously, the reference spectrum 110 is recorded during each measurement to calculate the sun protection factor 100 in order to detect any intensity changes and changes in the wavelength spectrum due to, for example, ageing of the individual radiation sources 12.1, 12.2, 12.3, 12.4, 12.5. Thereafter, a test measurement of the radiation source device 12 is performed using a measuring body 3 120. The test measurement includes a first activation of the radiation source device 12, a first emission of radiation from the radiation source device 12, the detection of the radiation diffusely reflected by a measuring body and the determination of the sensor sensitivity S.sub.T of a detector 13 as well as the determination of the target exposure time t.sub.Z and/or the target light power l.sub.Z for the radiation source device 12. Detailed explanations of the test measurement 120 are set out in previous embodiment examples (FIGS. 1-3).

[0071] In the next process step, recording of the measurement spectrum, 130 the spectrum determined by means of the test measurement 120 is irradiated onto the sample 3 by means of a second activation of the radiation source device 12, a total spectrum is composed of the partial spectra of the individual radiation sources 12.1, 12.2, 12.3, 12.4, 12.5 140 and the sun protection factor is calculated 150. For this purpose, a point on the inside of the forearm or the back of a test person 3 is usually exposed. This measuring location 3 is measured with the measuring system 1 by irradiating light at a defined area of about 500 μm diameter—generated, for example, by placing an optical fibre 4.1 (illumination fibre) with a core diameter of 500 μm. Smaller core diameters of, for example, 200 μm, 100 μm or 50 μm are also possible. The irradiation takes place with an intensity that does not cause acute damage to the skin, which is below the simple MED, or below the MZB values, or significantly below the values caused by solar radiation. 1 MED corresponds to the lowest irradiation dose that caused a sharply defined erythema (reddening) of the skin when read after 24 hours.

[0072] This light passes through the skin of the test person and emerges at a distance from a detection surface, which in turn consists of an attached optical fibre. To increase the sensitivity or further reduce the illumination intensity, several detection fibres 4.1, 4.2 can be arranged at the same or at least similar distance from the edge of the illumination fibre in an optical measuring head which is in direct contact with the measuring location 3 and guided together onto a detection device and thus the intensity measured. Depending on the level of intensity 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 for the subsequent measurement of the weaker intensity. The detection is wavelength-resolved. The resolution can be 1 nm, for example, and is to be selected depending on the definition of the light protection factor.

[0073] Furthermore, a repetition of the individual measurements during a measurement cycle is conceivable, whereby the individual measurements are averaged or accumulated. Furthermore, several measurements can be carried out periodically, for example every 5 seconds, and analysed until the deviation of the successive values is below the simple standard deviation, i.e. shows stable values. Such an evaluation takes place in the control device 2, which stops the measurement when the stable values are reached and signals this to a user.

[0074] In a variation of one of the above embodiments, a further measurement is also to be carried out at another measuring location 3 in the same way. This makes it possible to compare the light protection factor of the same radiation protection agent with the same type of application at different measuring locations 3.

[0075] FIG. 6 schematically shows an embodiment of the measuring system 1 according to the invention. The measuring system 1 has a radiation source device 12 with several radiation sources 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8. By means of a light guide 4.1 the spectrum emitted by the radiation source device 12 is introduced into the sample 3, the light reflected by the sample 3 reaches the spectrometer 13 via a further light guide 4.2. Spectrometer 13 and radiation source device 12 are connected via data lines 23, 24 to a radiation source control 11, which in turn is connected via a further data line 21 to the externally arranged control device 2. The control device 2 is usually a PC or notebook computer with a corresponding computer program. The control device 2 and the spectrometer 13 are also connected to each other via a data line 22.

[0076] The method for determining sun protection factors comprises a first activation of several radiation sources of a radiation source device having at least two radiation sources as well as a first emission of radiation from the at least two radiation sources. Subsequently, a detection of the radiation diffusely reflected by a measuring body takes place. Then the sensor sensitivity S.sub.T of a detector is determined and the target exposure time t.sub.Z and/or the target light power l.sub.Z for the at least two radiation sources is determined. Thereafter, a second triggering of several radiation sources of the radiation source device comprising at least two radiation sources takes place and a second emission of radiation (to the same measuring point as during the first emission) from the at least two radiation sources with a target exposure time t.sub.Z and/or the light power l.sub.Z of the first and the second radiation source of the radiation source device. The spectral reflectance measurement taken during the second emission is used for the calculation of the sun protection factor.

[0077] A detailed view of an embodiment of the measuring system 1 according to the invention is shown in FIG. 7. The measuring system 1 has a radiation source device 12 with five radiation sources 12.1, 12.2, 12.3, 12.4, 12.5. The radiation sources 12.1, 12.2, 12.3, 12.4, 12.5 are advantageously LEDs which have a particularly long service life. The spectral ranges of the individual LEDs differ from each other in such a way that a spectral range is covered, in particular in the UVA (315-380 nm) and UVB range (280-315 nm). The light emitted by the radiation sources 12.1, 12.2, 12.3, 12.4, 12.5 is bundled by a lens system 14, coupled into the light guide 4.1 and directed onto the sample 3. The light reflected by the sample 3 reaches the spectrometer 13 via a further light guide 4.2 through a further lens system 15. Spectrometer 13 and radiation source device 12 are connected via data line 24 to the radiation source control 11, which in turn is connected via a further data line to the externally arranged control device 2 (not shown, see FIG. 6). The radiation source control 11 controls the intensity and wavelengths of the radiation source device 12 and receives the data from the spectrometer 13 for this purpose.

[0078] The method for determining sun protection factors 100 comprises a first activation of several radiation sources of a radiation source device comprising at least two radiation sources as well as a first emission of radiation from the at least two radiation sources. Subsequently, a detection of the radiation diffusely reflected by a measuring body takes place. Then the sensor sensitivity S.sub.T of a detector is determined and the target exposure time t.sub.Z and/or the target light power l.sub.Z for the at least two radiation sources is determined 122. Then a second control of several radiation sources of the radiation source device having at least two radiation sources takes place and a second emission of radiation (to the same measuring point as during the first emission) from the at least two radiation sources with a target exposure time t.sub.Z and/or the light power l.sub.Z of the first and the second radiation source of the radiation source device. The spectral reflectance measurement taken during the second emission is used for the calculation of the sun protection factor.

REFERENCE LIST

[0079] 1 Measuring system [0080] 2 Control device [0081] 3 Sample/measuring body [0082] 4.1, 4.2 Light fibre/fibre bundle [0083] 11 Radiation source control [0084] 12 Radiation source device [0085] 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8 Radiation source/LED [0086] 13 Detector/Spectrometer [0087] 14 Lens system [0088] 14.1, 14.2, 14.3, 14.4, 14.5, 14.9 Lens [0089] 15 Lens [0090] 21 Connection radiation source control—radiation source device [0091] 22 Connection detector/spectrometer—control device [0092] 23 Connection radiation source control—control device [0093] 24 Connection radiation source control—detector/spectrometer [0094] 100 Method for the determination of sun protection factors [0095] 110 Recording a reference spectrum [0096] 120 Method for determining the target exposure time and/or the target light power [0097] 121 Recording a test spectrum for a radiation source [0098] 122 Determination of the target exposure time t.sub.Z and/or the target light output l.sub.Z [0099] 123 Query whether test spectra have been recorded for all radiation sources [0100] 125 Grouping of radiation sources [0101] 126 Recording of a test spectrum of a radiation source group [0102] 127 Determining the target exposure time t.sub.Z and/or the target light power l.sub.Z of the radiation source group [0103] 130 Method for recording a measurement spectrum [0104] 131 Recording a measurement spectrum [0105] 132 Filtering the measurement spectrum [0106] 133 Query whether a test spectrum has been recorded for each radiation source [0107] 134 Query whether the recording of a test spectrum for an untreated and sunscreen-treated measurement position has been made. [0108] 135 Recording a measurement spectrum with a radiation source group [0109] 136 Filtering the measurement spectra of the radiation source groups [0110] 137 Query whether a test spectrum has been recorded for each radiation source group [0111] 140 Composing an overall spectrum [0112] 150 Calculation of the sun protection factor [0113] 200 Method for recording a spectrum [0114] 210 Activating a radiation source [0115] 220 Recording a spectrum [0116] 230 Deactivating the previously activated radiation source [0117] 240 Query whether a spectrum has been recorded for each radiation source