EP2895843A1

EP2895843A1 - Measuring device for luminescence measurement

Info

Publication number: EP2895843A1
Application number: EP13759987.4A
Authority: EP
Inventors: Peter Kozma; Eva EHRENTREICH-FÖRSTER; Soeren Schumacher
Original assignee: Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
Current assignee: Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
Priority date: 2012-09-14
Filing date: 2013-09-11
Publication date: 2015-07-22
Also published as: WO2014040730A1; DE102012018303A1

Abstract

The invention relates to a measuring device for luminescence measurement comprising a sample carrier (8) for receiving a luminescent sample (9), a first lens array (13) having numerous lenses (14) arranged in a grid-shaped fashion and serving for focusing luminescent radiation emerging from the luminescent sample (9), and comprising a light sensor (16) for detecting the luminescent radiation emitted by the luminescent sample (9), wherein the light sensor (16) is arranged downstream of the first lens array (13) in the beam path of the luminescent radiation. It is proposed that the first lens array (13) is a first microlens array (13) having numerous microlenses (14), wherein a first perforated mask (11) having numerous holes (12) is arranged in the beam path of the luminescent radiation between the sample carrier (8) and the first microlens array (13), wherein the individual microlenses (14) and the holes (12) are assigned to one another and have corresponding axes. The sample carrier (8) can have a substantially planar waveguide (8), wherein the excitation radiation from an illumination unit (1) is coupled into a waveguide edge (10) of the waveguide (8).

Description

The invention relates to a measuring device for luminescence measurement.

Such a measuring device is known, for example, from US Pat. No. 5,827,748 and makes it possible, for example, to measure photoluminescence in the case of samples. The samples to be measured are in this case on a serving as a sample carrier transparent

Substrate arranged and optically excited by a lighting unit to cause photoluminescence. Below the transparent substrate serving as a sample carrier, a lens array, an optical filter and, finally, a light sensor which measures the luminescence radiation emanating from the sample are located behind one another in the beam path of the luminescence radiation.

A disadvantage of this known measuring device is the lacking possibility of extensive miniaturization, since the lens array is designed as a GRIN lens array (GRIN: graded index of refraction), which generally has a much greater thickness (typically more than 5 mm) as the height of a microlens in the microlens array (typically a few πμπι).

Furthermore, reference is made to the prior art to DE 197 48 211 AI, JP H10-311950 A, DE 197 28 966 AI, WO 03/093892 AI, DE 10 2011 114 500 AI, DE 601 22 735 T2, US 2003/0235905 AI DE 196 53 413 A1, WO 2005/068976 A2 and US Pat. No. 7,782,454 B2. However, ^{none of} these citations discloses an arrangement of the optical elements which enables in a simple manner a further miniaturization of the known luminescence measuring devices. The invention is therefore based on the object to provide a correspondingly improved measuring device.

This object is achieved by an inventive measuring device according to the main claim.

In this description it is stated that with a combination of a shadow mask and a microlens array a measuring device can be built whose thickness is substantially smaller than with a GRIN lens array.

The invention thus comprises the general technical teaching of replacing the GRIN lens array by a microlens array in the conventional measuring device described above, which is considerably thinner and therefore makes miniaturization possible.

In addition, the invention provides that a shadow mask with numerous holes is arranged in the beam path of the luminescence radiation between the sample carrier and the microlens array, wherein the individual microlenses and the holes are associated with one another and have matching axes. However, this shadow mask does not increase the thickness of the system because the object plane of the microlens array is above the shadow mask.

It should be mentioned here that the holes in the shadow mask are preferably arranged in the form of a grid, just as the individual microlenses in the microlens array are preferably arranged in the form of a grid. However, it is alternatively also possible that the individual holes in the shadow mask and the microlenses in the microlens array are arranged arbitrarily, ie without a grid-shaped or other geometric Order. All that matters is that the optical axes of the holes of the shadow mask on the one hand and the individual microlenses of the microlens array on the other hand coincide.

The microlens arrays used according to the invention are known per se from the prior art and therefore need not be described in detail. It should merely be mentioned at this point that the microlens array according to the invention is very thin and has a thickness which is preferably less than 2 mm, 1 mm, 500 μm, 200 μm, 100 μm or even less than 50 pm. As a result, the microlens array enables miniaturization of the measuring device according to the invention. Since the meter has only small and light elements, it can be portable or even be designed as a hand-held device.

In addition, in the beam path of the luminescence radiation emanating from the sample, further components are preferably arranged between the sample carrier and the light sensor, which are briefly described below.

For example, an optical filter (eg an interference filter) can be arranged between the sample carrier and the light sensor in the beam path of the luminescence radiation emanating from the sample, wherein the optical filter substantially reflects or absorbs an excitation radiation for the photoluminescent sample, while the optical filter Luminescence radiation emanating from the sample substantially passes. The optical filter is thus intended to prevent the ^¬ for the optical excitation of the photoluminescent sample ^¬ nende excitation radiation is misdiagnosed by the light sensor, as this leads to a falsification of the luminescence would lead. If the excitation radiation and the resulting luminescence radiation are in different wavelength ranges, this can be achieved by the optical filter having a corresponding spectral characteristic which blocks the excitation radiation, whereas the luminescence radiation is transmitted.

Moreover, in the beam path of the luminescence radiation emitted by the sample between the sample carrier and the light sensor, a further shadow mask with numerous grid-shaped holes can also be arranged. This further shadow mask coincides with the first shadow mask, preferably with regard to the arrangement of the holes, so that the holes of the two shadow masks lie one above the other in coincidence. However, the two shadow masks may differ in their thickness and in the diameter of their holes. This additional shadow mask has the function of further minimizing the overlapping of the measuring regions and reducing the background intensity.

Furthermore, within the scope of the invention it is possible for a further microlens array with numerous microlenses to be arranged in the beam path of the luminescence radiation emanating from the sample between the sample carrier and the light sensor. The optical axes of the individual Mikrolin ^¬ sen this further microlens array preferably coincide with the optical axes of the other microlens array, and the holes of the shadow mask.

Finally, within the scope of the invention, there is the possibility that a third shadow mask with numerous holes is arranged in the beam path of the luminescence radiation emanating from the sample between the sample carrier and the light sensor, the holes preferably being distributed in grid form are. However, it is important only that the holes of the third shadow mask coincide with the holes of the other shadow masks and the microlenses of the microlens arrays. With regard to the arrangement of the components described above in the beam path of the emanating from the sample luminescence between the sample carrier and the light sensor exist within the scope of the invention, various possibilities, of which three variants are described below.

In a first variant, the first shadow mask, the first microlens array and the optical filter are arranged one behind the other in the beam path of the luminescence radiation emanating from the sample between the sample carrier and the light sensor.

In a second variant of the invention, however, are in

Beam path of the luminescence radiation behind the first hole mask, the first microlens array, the optical filter and the second shadow mask arranged.

In a third variant of the invention, the first shadow mask, the first micro-lens array, the second shadow mask, the second microlens array, the third shadow mask and the optical filter are located one behind the other in the beam path of the luminescence radiation emanating from the sample.

However, the invention is not limited to the three variants described above, but in principle can also be implemented with other sequences of components in the beam path of the luminescence radiation emanating from the sample, whereby further components can also be added. In the variant with two microlens arrays described above, the two microlens arrays preferably have a common image and object plane lying in the plane of the third shadow mask, ie the second shadow mask following in the beam path. This quasi-confocal adjustment of the microlenses of the two microlens arrays, together with the thin hole mask in between, enables the measurement of only the fluorescence signals coming from the image and object plane of the microlenses of the first microlens array. Preferably, this plane coincides with the surface of the sample carrier (eg waveguide) on which the fluorescent material lies.

It has already been mentioned above that the shadow masks and the microlens arrays preferably have matching grid dimensions. This means that the holes or microlenses are arranged in a grid-shaped manner at a predetermined distance from each other and at predetermined positions.

However, it is within the scope of the invention that the holes in the different shadow masks have a different size, as already briefly mentioned above.

In addition, the different shadow masks can also have different thicknesses, as has already been mentioned above.

It should also be mentioned that the holes in the individual shadow masks can be made with a transparent filling material and in the case of the third shadow mask this transparent filling material should preferably have the same refractive index as the material of the microlenses of the microlens arrays. The filling of the holes can be done either with one, several or all shadow masks. It should also be mentioned that the optical axes of the individual microlenses of the microlens arrays preferably each extend coaxially to the holes of the shadow masks adjacent in the beam path.

The individual shadow masks preferably have a thickness of less than 3 mm, 1 mm or 0.5 mm in order to allow miniaturization of the measuring device according to the invention.

It should also be mentioned that at least the microlens arrays, the optical filter and the light sensor can be glued together, for example by means of an optical fine cement (eg Norland liquid), whose refractive index is preferably uniform with the material refractive index of the microlens arrays, which makes it practical save at least one optical interface.

Furthermore, within the scope of the invention it is also possible for the optical filter to be vapor-deposited as a layer on at least one surface of a microlens array of the light sensor.

In a preferred embodiment, the sample carrier used is a waveguide in which the excitation radiation can propagate to excite the photoluminescent sample. The measuring device according to the invention therefore preferably also comprises a lighting unit to generate the excitation radiation to excite the photo-luminescent sample, wherein the excitation radiation is coupled from the lighting unit in the waves ^¬ conductor.

In the preferred embodiment of the invention, the waveguide is substantially planar and has a waveguide. Edge, wherein the excitation radiation of the illumination unit is coupled through the waveguide edge of the waveguide. However, the coupling of the excitation radiation into the waveguide can also take place in a planar waveguide in a different manner, for example by means of gratings or prisms.

In this case, it is advantageous if the illumination unit has a specific focal plane, wherein the waveguide edge of the waveguide lies in the focal plane of the illumination unit.

In addition, it is advantageous if the illumination unit generates a light line that runs along the waveguide edge, so that the excitation radiation is coupled into the waveguide even over the entire length of the waveguide edge. In this case, there is the possibility that a diaphragm is arranged in the beam path of the excitation radiation in front of the waveguide edge, which passes through the excitation radiation to the waveguide edge, while the diaphragm otherwise shields the excitation radiation. This is advantageous because it reduces the risk of misdetection of the excitation radiation by the light sensor.

The invention is not limited to a specific structure with regard to the structural design of the lighting unit. However, the lighting unit may include various ^¬ dene components which are briefly described below. Thus, the illumination unit initially has a light source in order to generate the excitation radiation for exciting the photoluminescent sample. The light source is preferably a laser diode, but other types of light sources can be used within the scope of the invention.

In addition, the illumination unit preferably has an optical filter which only passes through a narrow-band wavelength spectrum, the optical filter being arranged in the beam path of the light source. The spectral filter characteristic of the optical filter is designed, for example, such that the wavelengths required for the optical excitation of the photoluminescence are transmitted, whereas the wavelength spectrum of the luminescence radiation is blocked. This is advantageous because the risk of misdetection of the excitation radiation by the light sensor is lower due to this wavelength separation. For example, the optical filter can be an interference filter, but the invention can also be implemented with other types of filters.

In addition, the illumination unit according to the invention preferably comprises a line lens which expands the light beam emanating from the light source to a line of light to illuminate the waveguide edge over most of its length. The line lens is preferably arranged in the beam path of the light source behind the optical filter.

Finally, the lighting unit preferably includes a cylindrical lens for reducing the divergence of the light emitted from the illumination unit Be ^¬ excitation radiation, wherein the cylindrical lens in the beam path of the light source is preferably disposed behind the line lens. It has already been briefly mentioned above that the sample carrier is preferably designed as a waveguide. With regard to the arrangement of the sample on the waveguide, there are various possibilities. Thus, the sample and the light sensor may be disposed on opposite sides of the waveguide. However, in principle there is also the possibility that the sample and the light sensor are arranged on the same side of the waveguide, which is less preferred. Furthermore, there is also the possibility that the sample is arranged in the waveguide itself.

The waveguide is preferably transparent at least for the serving for exciting the photoluminescent sample excitation radiation, preferably completely or to ^¬ least in one layer. Moreover, the waveguide in the transparent layer preferably has a refractive index which is greater than the refractive index of the environment, in particular on the side of the sample and on the side of the light sensor.

Finally, it should also be mentioned that the light sensor preferably has a planar detector surface which is arranged parallel to the planar sample carrier (eg waveguide). The light sensor can be, for example, a CCD sensor (CCD: Charge-Coupled Device) or a CMOS sensor (CMOS: Complementary Metal Oxide Semiconductor), but in principle the invention can also be implemented with other types of light sensors. Other advantageous developments of the invention are characterized in the sub claims or hereinafter zusa ^¬ mmen with the description of the preferred embodiments of the invention are explained in more detail with reference to FIGS. Show it: FIG. 1A a schematic representation of a measuring device according to the invention with a lighting unit and a readout system,

FIG. 1B shows a simplified exploded view of the readout system according to FIG. 1A,

FIG. 2A shows a modification of the readout system from FIG. 1A with a plurality of microlens arrays and a plurality of shadow masks,

FIG. 2B shows a simplified exploded view of the read-out system from FIG. 2A,

Figure 3A is a modification of Figure 2A, Figure 3B is a modification of Figure 2B, and

Figure 4 is an exploded view of an inventive

Measuring device according to another embodiment.

Figures 1A and 1B show a first embodiment of a measuring device according to the invention for the measurement of photoluminescence, wherein the measuring device consists essentially of the lighting unit 1 and a readout system 2.

The illumination unit 1 has as a light source a Laserdi ^¬ ode 3, which emits a light beam 4 for Photolumineszenzan ^¬ movement.

In the beam path of the light beam 4, behind the laser diode 3, first an interference filter 5 is arranged, which passes only a narrow wavelength interval of the light beam 4. The spectral characteristic of the interference filter 5 is here tuned so that the interference filter 5 transmits the required for photoluminescence excitation radiation, whereas the interference filter 5 blocks the resulting luminescence. This spectral separation of the excitation radiation from the luminescence radiation offers the possibility of preventing crosstalk of the laser diode 3 onto the readout system 2, as a result of which the risk of misdetection of the excitation radiation is lower. Furthermore, a line lens 6 is arranged in the beam path of the light beam 4 behind the interference filter 5, which fanning the light beam 4 at right angles to the plane and generates a light line, which is advantageous for coupling the excitation radiation in the readout system 2, as will be described in detail.

Finally, the illumination unit 1 also comprises a cylindrical lens 7 which is arranged behind the line lens in the beam path of the light beam 4, the cylindrical lens 7 minimizing the divergence of the light beam 4.

The readout system 2 has a planar waveguide 8 as a sample carrier, wherein the waveguide 8 can always be positioned at the same position on a sensor surface of the readout system 2 with the aid of a fixing frame (not illustrated here).

On the upper surface of the waveguide 8 in the drawing are the samples 9 to be measured, which are photoluminescent samples which are excited by the excitation radiation from the illumination unit 1 for photoluminescence. The excitation radiation is coupled into the readout system 2 via a waveguide edge 10 of the waveguide 8. The light line generated by the illumination unit 1 coincides here with the waveguide edge 10, which enables an efficient coupling of the excitation radiation in the waveguide 8.

The light coupled into the waveguide 8 exciting radiation from the illumination unit 1 propagated in the waveguide 8. The waveguide 8 is thus completely or at least transparent in a layer for the wavelength of the originating from the Be ^¬ illumination unit 1 excitation radiation so that the excitation radiation to the sample 9 can get. In addition, the refractive index of the Wellenlei- ters 8 in the transparent region is larger than the refractive index of the ^¬ environment. This ensures that the excitation radiation emanating from the illumination unit 1 can propagate within the waveguide 8 and excite the photoluminescent samples 9. Here, the photo- luminescent samples 9 is excited ^¬ on the surface of the waveguide 8 by the evanescent field of the propagating light modes.

Moreover, lenleiters 8 is a shadow mask 11 having a number of grid-like arranged holes 12, a microlens array 13 having a number of grid-like arranged microlenses 14, an opti ^¬ ULTRASONIC filter 15 and finally a CCD sensor 16 to the read-out system 2 below the WEL. The shadow mask 11 and the microlens array 13 in this case have matching grid dimensions, so that the optical axes of the individual microlenses 14 of the microlens array 13 coincide with the holes 12 of the shadow mask 11. On the one hand, the shadow mask 11 serves as incident direction filter, which prevents the overlapping of different measuring regions.

On the other hand, the shadow mask 11 also serves as a spacer between the surface of the waveguide 8 and the microlens array 13.

The optical filter 15 is preferably an interference filter that reflects or blocks the wavelength of the excitation radiation originating from the illumination unit 1, whereas the optical filter 15 transmits the wavelength of the luminescence radiation originating from the samples 9. In this way, the optical filter 15 prevents crosstalk of the excitation radiation originating from the illumination unit 1 to the CCD sensor 16.

The CCD sensor 16 measures the originating from the sample 9 Lu ^¬ mineszenzstrahlung under each grid point independently and forwards measured values corresponding with its readout electronics further to a computer, where takes place later image processing. The readout system 2 thus enables the photoluminescence measurement at the point where the fluorescence signal of the sample 9 passes through the waveguide 8 and then through the corresponding hole 12 of the shadow mask 11 and with the help of the microlens array 13 on the surface of the CCD Sen ^¬ sors 16 is shown.

Figures 2A and 2B show a modification of the embodiment according to FIGS 1A and 1B, reference is therefore made to avoid repetition of the foregoing description, and the same for corresponding details reference sign ^¬ be used. A special feature of this embodiment is that in the readout system 2 in the beam path of the luminescence between the optical filter 15 and the CCD sensor 16, a further shadow mask 17 is arranged with numerous grid-shaped holes 18. The shadow mask 17 coincides with the shadow mask 11 with regard to the grid dimension of the holes 18. However, the two shadow masks 11, 17 differ in terms of their thickness and in terms of the diameter of the holes 12, 18. The additional shadow mask 17 has the task of further minimizing the overlapping of the measuring regions and reducing the background intensity.

FIGS. 3A and 3B show a further modification of the embodiment according to FIGS. 1A and 1B or 2A and 2B, so that reference is made to the above description to avoid repetition, the same reference numbers being used for corresponding details.

A special feature of this embodiment is that the second shadow mask 17 is arranged in the beam path of the luminescence radiation ^¬ front of the optical filter 15 and behind the micro-lens array. 13

In addition, the read-out system 2 in this exemplary embodiment has a further microlens array 19 with numerous microlenses 20 and a further shadow mask 21 with numerous holes 22, the microlens arrays 13, 19 and the shadow masks 11, 17, 21 having matching grid dimensions, such that the holes 12, 18, 22 of the shadow masks 11, 17, 21 coincide with the optical axes of the microlenses 14, 20 of the microlens arrays 13, 19. The two microlens arrays 13, 19 hereby have common image and object planes that lie in the plane of the shadow mask 21.

It should also be mentioned that the holes 22 of the shadow mask 21 are filled with a transparent filling material, wherein the refractive index of the filling material coincides with the refractive index of the material of the microlens arrays 13, 19.

This quasi-confocal adjustment of the microlenses of the microlens arrays 13, 19, together with the shadow mask 17 located therebetween, enables the measurement of only the fluorescence signals coming from the first object plane of the microlenses 14 of the microlens array 13.

FIG. 4 shows a further exemplary embodiment of a measuring device according to the invention for luminescence measurement. This exemplary embodiment largely corresponds to the exemplary embodiments described above, so that reference is made to the above description to avoid repetition, the same reference numerals being used for corresponding details.

In addition, this drawing also shows a cover 23 and a spacer 24th

The above-described embodiments of a measuring device according to the invention advantageously allow miniaturization, which allows use in so-called point-of-care diagnostics. In addition, due to its miniaturization, the measuring device according to the invention can also be used in mobile laboratories, for example in ambulances. The invention is not limited to the preferred embodiments described above. Rather, a multiplicity of variants and modifications is possible, which likewise make use of the concept of the invention and therefore fall within the scope of protection. Moreover, the invention also claims protection for the subject matter and the features of the subclaims independently of the claims referred to.

List of reference numbers:

1 lighting unit

2 readout system

3 laser diode

4 light beam

5 interference filters

6 line lens

7 cylindrical lens

8 waveguides

9 samples

10 waveguide edge

11 shadow mask

12 holes in the shadow mask 11

13 microlens array

14 microlenses of the microlens array 13

15 Optical filter

16 CCD sensor

17 shadow mask

18 holes in the shadow mask 17

19 microlens array

20 microlens of the micro-lens array 19

21 shadow mask

22 holes in the shadow mask 21

23 cover

24 spacers

Claims

1. Measuring device for luminescence measurement with

a) a sample carrier (8) for receiving a luminescent sample (9),

b) a first lens array (13) with numerous raster-shaped lenses (14) for imaging luminescence radiation emanating from the luminescent sample (9), and

c) a light sensor (16) for detecting the luminescence radiation emitted by the luminescent sample (9), the light sensor (16) being arranged in the beam path of the luminescence radiation behind the first lens array (13),

characterized,

d) that the first lens array (13) is a first microlens array (13) with numerous microlenses (14) and e) that in the beam path of the luminescence radiation between the sample carrier (8) and the first microlens array

(13) a first shadow mask (11) with numerous holes (12) is arranged, wherein the individual microlenses

(14) and the holes (12) are associated with each other and have matching axes.

2. Measuring device according to claim 1, characterized in that in the beam path of the sample (9) outgoing luminescence radiation between the sample carrier (8) and the light sensor (16) at least one of the following components is arranged:

a) an optical filter (15), in particular an interference filter, wherein the optical filter (15) has a stimulus radiation (4) for the luminescent sample (9) substantially reflected or absorbed, while the optical filter (15) from the sample (9) emanating outgoing luminescence substantially, b) a second shadow mask (17) with numerous grid-shaped holes arranged (18)

c) a second microlens array (19) having a plurality of microlenses (20) arranged in the form of a grid,

d) a third shadow mask (21) with numerous grid-shaped holes (22).

3. Measuring device according to claim 2, characterized in that a) that the first shadow mask (11), the first microlens array (13) and the optical filter (15) in the beam path of the sample (9) emanating luminescence radiation between the sample carrier ( 8) and the light sensor (16) are preferably arranged one behind the other in this order, or

b) that the first shadow mask (11), the first microlens array (13), the optical filter (15) and the second

Shadow mask (17) in the beam path of the sample (9) outgoing luminescence radiation between the sample carrier (8) and the light sensor (16) are preferably arranged in this order one behind the other, or c) that the first shadow mask (11), the first microlens Array (13), the second shadow mask (17), the second microlens array (19), the third shadow mask (21) and the optical filter (15) in the beam path between the sample carrier (8) and the light sensor (16) preferably in arranged in this order one behind the other.

4. Measuring device according to claim 3, characterized in that a) that the first microlens array (13) and the second Microlens array (19) have a common image and object plane, and

in that the common image and object plane of the first microlens array (13) and of the second microlens array (19) lies in the plane of the third shadow mask (21).

5. Measuring device according to one of claims 2 to 4,

characterized,

a) that the first shadow mask (11), the second shadow mask

(17), the third shadow mask (21), the first microlens array and / or the second microlens array have matching grid dimensions, and / or

b) that the first shadow mask (11), the second shadow mask

(17) and / or the third shadow mask (21) have different sized holes (12, 18, 22), and / or

c) that the first shadow mask (11), the second shadow mask

(17) and / or the third shadow mask (21) have different thicknesses, and / or

d) that at the first shadow mask (11) and / or at the

second hole mask (17) and / or in the third shadow mask (21) the holes (12, 18, 22) are filled with a transparent filler material, wherein the transparent filler material in the second shadow mask (17) preferably has the same refractive index as the microlenses of Microlens arrays, and / or

e) that the optical axes of the individual microlenses

(14, 20) of the microlens arrays (13, 19) in each case extend coaxially to the holes (12, 18, 22) of the adjacent shadow masks (11, 17, 21), and / or

f) that the first microlens array (13) and / or the

second microlens array (19) has a thickness of less as 2mm, 1mm, 500μπι, 200μπι, 100μm or 50μιη has, and / or

g) that the first shadow mask (11), the second shadow mask

(17) and / or the third shadow mask (21) has a thickness of less than 3 mm, 1 mm or 0.5 mm, and / or h) that at least the microlens arrays (13, 19), the optical filter (15) and the Light sensor (16) are glued together, in particular by means of an optical Feinkitts whose refractive index is preferably uniform with the Materialbrechugsindex the microlens arrays, and / or

i) that the optical filter (15) is deposited as a layer on at least one surface of a microlens array (13, 19) or the light sensor (16), and / or j) that the measuring device is portable, in particular as a hand-held device, and /or

k) that the second shadow mask (17) is thinner than the first shadow mask (11) and / or as the third shadow mask (21), and / or

1) that the holes (18) of the second shadow mask (17) are smaller than the holes (12) of the first shadow mask (11) and / or as the holes (22) of the third shadow mask (21).

6. Measuring device according to one of the preceding claims, characterized in that the sample carrier (8) has a waveguide (8).

7. Measuring device according to claim 6, characterized in that a) that the sample (9) is photoluminescent,

b) that the measuring device for excitation of the photoluminescent

Sample (9) with an excitation radiation (4) has a lighting unit (1), and c) that the excitation radiation from the lighting unit (1) is coupled into the waveguide (8).

8. Measuring device according to claim 7, characterized in that a) that the waveguide (8) is substantially planar and has a waveguide edge (10), and

b) that the excitation radiation from the illumination unit

(1) is coupled into the waveguide edge (10) of the waveguide (8).

9. Measuring device according to claim 8, characterized in that a) that the illumination unit (1) has a certain focal plane, wherein the waveguide edge (10) of the waveguide (8) in the focal plane of the illumination unit (1), and / or

b) that the illumination unit (1) generates a light line, wherein the light line runs along the waveguide edge (10), and / or

c) that in the beam path of the excitation radiation (4) in front of the waveguide edge (10), a diaphragm is arranged, wherein the aperture the excitation radiation (4) to the waveguide edge (10) passes, while the aperture, the excitation radiation (4) otherwise shields.

10. Measuring device according to one of claims 7 to 9, characterized in that the illumination unit (1) has at least one of the following components:

a) a light source (3), in particular a laser diode or a laser, for generating the excitation radiation (4) for exciting the photoluminescent sample (9),

b) an optical filter (5), in particular an interference filter, which only has a narrow-band wavelength spectrum lets through, the optical filter (5) being arranged in the beam path of the light source (3),

c) a line lens (6) for generating the light line, wherein the line lens (6) in the beam path of the light source

(3) is preferably arranged behind the optical filter (5),

d) a cylindrical lens (7) for reducing the divergence of the illumination unit (1) emitted excitation radiation (4), wherein the cylindrical lens (7) in the beam path of the light source (3) preferably behind the line lens (6) is arranged.

11. Measuring device according to one of claims 6 to 10,

characterized,

a) that the sample (9) on the waveguide (8) is arranged, wherein the sample (9) and the light sensor (16) are preferably arranged on opposite sides of the waveguide (8), or

b) that the sample (9) is arranged in the waveguide (8).

12. Measuring device according to one of claims 6 to 11,

characterized,

a) that the waveguide (8) for the excitation radiation

(4) is transparent to the excitation of the photoluminescent sample (9) at least in one layer, and / or b) that the waveguide (8) in the transparent layer has a refractive index which is greater than the refractive index of the environment, in particular on the side the sample (9) and on the side of the light sensor (16).

13. Measuring device according to one of the preceding claims, characterized

a) that the light sensor (16) has a planar detector surface, which is arranged parallel to the planar sample carrier (8), and / or

b) that the light sensor (16) is a CCD sensor or a CMOS sensor.