WO2018011223A1

WO2018011223A1 - Opto-electronic measuring device for a color measuring device

Info

Publication number: WO2018011223A1
Application number: PCT/EP2017/067439
Authority: WO
Inventors: Wolf-Dieter PRENZEL
Original assignee: Net Se
Priority date: 2016-07-12
Filing date: 2017-07-11
Publication date: 2018-01-18
Also published as: DE102016112750A1

Abstract

The present invention relates to an opto-electronic measuring device (1) for a color measuring device, in particular a hand-held color measuring device for use on screens, comprising at least one primary optical unit (2), at least one diaphragm (3), at least one diffuser (4) and at least one sensor unit (5), wherein the measuring device (1) is designed in such a manner that, in the presence of the measuring device (1) in a measuring state, light beams (7) emitted by a measurement object (6) meet the primary optical unit (2) and can be at least partially bundled by means of the primary optical unit (2), wherein the primary optical unit (2) is arranged relative to the diffuser (4) in such a way that the diffuser (4) lies at least substantially in the focus of the primary optical unit (2), wherein the diaphragm (3), when seen in the radiation direction of the light beams (7), is arranged upstream of the diffuser (4) and delimits an angle of incidence of the light beams (7). The light beams (7) can be homogenized by means of the diffuser (4) so that they can be uniformly directed on the sensor unit (5) when parting from the diffuser (4), wherein the light beams (7) can be converted into electrical signals by means of the sensor unit (5). The invention is characterized in that the sensor unit (5) is formed by an integral multi-spectral sensor which has at least three partial surfaces (8) for detecting in each case different spectral components. In order to produce a color measuring device which, in comparison to the prior art, can be used in a manner that is as simple and reliable as possible, it is proposed according to the invention that the primary optical unit (2) comprises at least one contiguous lens body (29) which has two regions of different dispersion and/or a total of at least three refractively and/or reflectively effective surfaces (9).

Description

Page 1 of 19

Opto-electronic measuring device for a colorimeter

description

introduction

The present application relates to an optoelectronic measuring device for a color measuring device, in particular a handheld colorimeter for use on screens, comprising at least one primary optics, at least one aperture, at least one diffuser and at least one sensor unit, wherein the measuring device is designed such that when the measuring device is present in a measuring state, light rays emanating from a measuring object strike the primary optics and are at least partially bundled by means of the primary optics, the primary optics being arranged relative to the diffuser such that the diffuser lies at least substantially in the focus of the primary optics, wherein the aperture is arranged in front of the diffuser in the direction of radiation of the light beams and limits an angle of incidence of the light beams, whereby the light beams can be homogenized by means of the diffuser, so that they are uniformly distributed on the diffuser from the diffuser

Sensor unit are conductive, wherein the light beams are convertible by means of the sensor unit into electrical signals, wherein the sensor unit of an integral

Multiple spectral sensor is formed, which has at least three sub-areas for detecting each different spectral components.

[02] Furthermore, the present application relates to a method for operating a measuring device, comprising the following method steps:

a) The measuring device is aligned relative to the measuring object, so that of

the light beam emitted by the measuring device by means of the measuring device

are detectable.

b) A measurement of the measurement object is performed, wherein light rays by means of

The measuring device recorded on the color to be analyzed.

c) Actual color values determined in this way are compared with desired color values of the light beams emanating from the measurement object.

d) The measured object is driven at least indirectly to its

To change color rendering such that the actual color values change in the direction of the desired color values.

[03] For the purposes of the present application, a "primary optics" is understood to mean an arrangement of at least one component which is suitable for the course of Page 2 of 19

To influence light rays. In particular, a primary optic may comprise one or more lenses, for example condenser lenses or scattered lenses.

[04] For the purposes of the present application, a "diaphragm" is understood to mean a device which prevents the passage of light beams and in this way can have an aperture-limiting effect

present application, the diaphragm be formed by a so-called aperture diaphragm.

[05] For the purposes of the present application, a "diffuser" is understood to be a device by means of which incident light can be homogenized, that is to say a light striking a diffuser is dissipated by the effect of the diffuser in such a way that the light emanates from an exit surface of the diffuser evenly distributed

Exit surface of the diffuser is in particular no discrete, punctiform light source recognizable. Instead, it typically appears that the light emits relatively uniformly, starting from the exit face of the diffuser.

[06] For the purposes of the present application, a "sensor unit" is a unit by means of which it is possible to convert light beams into electrical signals, the conversion being possible depending on certain properties of the light beams. radiometric and colorimetric values of the respective light radiation, in particular the luminous flux, the luminous intensity or the luminance. [07] Within the meaning of the present application, an "integral multiple spectral sensor" is understood to mean a sensor unit which is suitable for supplying different spectral fractions of detected light beams determine only a single

Sensor unit is necessary. Consequently, such an integral multi-spectral sensor does not require a plurality of different sensor units arranged separately from one another, which moreover possibly has to interact with individual corresponding color filters. Such a space-consuming and thus disadvantageous arrangement, for example, the above-mentioned European patent application can be removed.

State of the art

[08] Measuring devices of the type described above are already known in the art. In particular, they can be used in combination with colorimeters that can be used to color-calibrate screens, such as monitors or televisions. For this purpose, light emitted by a respective measuring surface, for example the screen of a monitor, is emitted by means of the respective color measuring device Page 3 of 19 and examined for their condition. This study can be done in different ways; In particular, it may be of interest to

Color rendering of the respective measurement object to determine. Based on the respectively recorded values, it is then possible to adjust the item being examined in such a way that, for example, the colors output are changed and thus adapted to "real" colors also suitable for compensating color changes occurring over the service life of the respective screen. [09] Color measuring devices which are suitable for such measurements are shown, for example, in the documents DE 10 2013 004 213 A1, EP 2 505 973 A2 and US 7,671, 991 B2 In particular, the said European patent application describes the structure of the measuring device used in the color measuring device presented there.

This is a measuring device of the type described above. Another example of a generic measuring device is described in US Patent Application 2013/0027696 A1.

The known colorimeters have the particular disadvantage that they are relatively sensitive in their application. In particular, care must be taken that the measuring devices are aligned exactly with the respective measurement object in order to be able to carry out a reliable measurement. In practice, this sensitivity of the measurement results relative to the arrangement of the measuring device often

Multiple measurements of one and the same object to be measured, since a particular measurement either directly detectable errors included or at least a measurement result is not trusted without control. task

The present invention has for its object to produce a colorimeter that is as simple and reliable as possible compared to the prior art.

Solution [12] According to the invention, the object underlying the invention is achieved on the basis of the measuring device of the type described in the introduction in that the primary optics has at least one coherent lens body, which has two regions Page 4 of 19 different dispersion and / or a total of at least three refractive and / or reflective effective surfaces.

[13] A "contiguous lens body" is understood to mean a component through which the light beam passes in such a way that the light beam enters the lens body at an entrance surface from the environment

(typically transition air-lens) and exit at an exit surface from the lens body back to the environment (typically transition lens-air). The simplest example of a lens body is a single lens. However, it is also conceivable that a lens body in the context of the present application by a plurality, in particular two, lenses is formed, which cooperate such that the light beam from the first lens to the second lens, without transition in the meantime in the environment. Instead, the light beam passes directly from one lens to the other lens. Such an arrangement is realized, for example, in a two-lens achromatic. [14] The measuring device according to the invention has many advantages. In particular, the primary optics according to the invention is suitable for reducing aberrations, in particular color aberrations (chromatic aberration) and sharpness aberrations (spherical aberration), preferably to eliminate them. This increase in quality significantly reduces the susceptibility of the measuring device as a whole to the typical optics of the measuring devices according to the prior art. The result of this is that the device according to the invention is much less susceptible to "wrong" alignment with respect to the device compared with those of the prior art

Measuring object is. For example, this is reflected in the fact that the

Measuring device according to the invention can also achieve usable measurement results, if it is aligned or arranged obliquely to a measuring surface of the measuring object and / or spaced from the same.

For this purpose, in particular such a primary optics of advantage, which is not imaged, preferably wherein the diffuser outside a focal plane of the

Primary optic, further preferably from the primary optic view on this side of the

Focal plane, lies.

Additionally or alternatively, the primary optics should be tuned and cooperate with the diaphragm such that at least substantially only those light beams reach the diffuser which extend at least substantially parallel to an optical axis of the measuring device before a first deflection or deflection by the primary optics , Page 5 of 19

In this way, the measuring device is overall very robust against incidental extraneous light from the side, for example against incident ambient light, as this does not reach the diffuser due to the vote of the optics. In particular, the

Measuring device be designed such that only such light rays on the diffuser, which meet at an angle of incidence of less than 10 °, preferably less than 5 °, on an entrance surface of the measuring device.

[17] In an advantageous embodiment, the primary optics may for example comprise a lens body having only a portion of a dispersion, wherein the

Lensenkörper is formed by a TIR collimator lens with at least three reflective and / or refractive surfaces. Such a primary optics achieves a deflection of the light beams emanating from the measurement object at least partially by means of reflection at an aspherically curved rear surface of the associated lens. Reflections do not lead to the known aberrations, so that the primary optics has at least a significantly increased quality of the light pipe to the diffuser. Furthermore, it may be advantageous if the lens body has two areas

having different dispersion, wherein the lens body is formed by a two-lingual Achromaten. In this two lenses of the achromat are directly connected to each other, wherein one of the lenses has a positive and the other lens has a negative refractive power. Such a lens body or a primary optic equipped with such a lens is also at least substantially free of

Aberrations, preferably the achromat in the form of an aspherical

Achromats is designed to also achieve a correction of the sharpness error in addition to a correction of the color aberration.

[19] In addition to the increased reliability, the measuring device according to the invention also has the advantage that it builds comparatively compact. The use of the integral

Namely multiple spectral sensor leads to the fact that the space of the measuring device "behind the diffuser" compared to the prior art can be extremely low.

In particular, it is conceivable to arrange an integral multiple spectral sensor, so to speak, directly on a rear exit face of the diffuser. The

The need for a secondary optics, the light emitted from the diffuser first on different color filters and then on the corresponding with these individual

Distributing sensors is no longer a given.

The reduction of the length of the measuring device is already to be evaluated as advantageous for the reasons mentioned above. Conversely, the Page 6 of 19

Construction method are also used while maintaining a typical length equal to the measuring surface of the measurement object, from which light rays entering the measuring device and thus can be evaluated, to increase in comparison to the prior art. In particular, such an embodiment is advantageous in which a ratio between the measuring surface of the test object and the sensor surface of the sensor unit is at least 1: 150, preferably at least 1: 125, more preferably at least 1: 100.

[21] Advantageously, the integral multiple spectral sensor is formed by an integral RGB sensor having at least three different types of sub-areas, one of the sub-areas being designed to detect a red, a green and a blue spectral component of the light beams. In particular, such an integral RGB sensor can be formed by a large number of individual sensors, each of which has three subareas. The different sensitivities of the partial surfaces for the desired spectral components can be formed, for example, by means of integral color filters which are arranged directly on the respective partial surface.

In any case, it is inventively possible to arrange the sensor unit of the measuring device in a particularly small distance behind the diffuser, advantageously at a distance of not more than 2 mm, preferably not more than 1 mm, more preferably not more than 0.5 mm. These distances are understood in the direction of radiation of the respective light beams.

[23] Furthermore, it may be of particular advantage if the outlet surface of the diffuser and a sensor surface of the sensor unit have an at least substantially, preferably completely, coincident aperture. In other words, in this embodiment, the diffuser and the sensor unit are matched directly to one another, wherein due to the arrangement of the two components directly one behind the other, the surfaces thereof can be formed virtually identical.

[24] Advantageously, the measuring device according to the invention can be supplemented with a further lens with positive refractive power. Such a lens is suitable for further focusing the light beams impinging on it and in this way shortening the overall length of the measuring device as a whole. The further lens is advantageously arranged between the continuous lens body and the diffuser.

Furthermore, it may be particularly advantageous if the measuring device is equipped with a secondary optics, which is viewed in the radiation direction of the light rays between the diffuser and the sensor unit. The secondary optics is to Page 7 of 19 suitable to direct outgoing light rays from the diffuser on the sensor unit. Such an arrangement may be required if the sensor unit is not to be located immediately behind the diffuser.

Such secondary optics may be formed, for example, by a light guide, wherein a cross section of the light guide must be adapted at its respective ends in each case to the apertures of the diffuser or the sensor unit. It is also conceivable to form a secondary optic from a lens, in particular from a gradient lens, and to achieve an approximation between the apertures of the diffuser and the sensor unit by means of the secondary optics. Furthermore, it is advantageous regardless of the other embodiment of the measuring device according to the invention, when the diffuser is formed of quartz glass. A diffuser formed by quartz glass in particular has the advantage that the spectral properties of the light rays striking the diffuser are not changed. In addition, a diffuser formed by quartz glass has a plurality of internal scattering centers, which are important for a particularly pronounced homogenization of the light striking the diffuser. Such a diffuser emits light in all directions evenly and thus acts as Lambert radiator. In other words, such a quartz glass diffuser is particularly well suited to disperse the light striking it. Furthermore, quartz glass diffusers are characterized by a complete depolarization and an extreme long-term stability and UV resistance compared to conventional diffusers.

[28] It is particularly advantageous, regardless of the material of which the diffuser is formed, if it has a thickness measured in the direction of radiation of the light rays of at least 0.3 mm, preferably at least 0.5 mm, more preferably at least 1 mm , having. Such a thickness of the diffuser is in view of

Homogenization of the incident on the diffuser light rays particularly advantageous because in the comparatively large volume of the diffuser a higher number of scattering centers is present at which the light rays can be scattered.

[29] From a process engineering point of view, the underlying object is achieved according to the invention by the following method step:

e) Before performing the measurement, an optical axis of

Measuring device with respect to a surface normal, which is perpendicular to an emission surface of the measurement object, aligned twisted, so that the optical axis and the surface normal together include an angle greater than 0 °. Page 8 of 19

[30] This method step is particularly easy to carry out by means of the measuring device according to the invention. The method is advantageous insofar as the twisted alignment of the measuring device relative to the measurement object is even possible, while in the prior art in each case a conscientious error-prone alignment is required, which nevertheless has a relatively high error rate. The

In contrast, the method according to the invention is particularly simple and quick to carry out, whereby the comfort for the user of the measuring device is significantly increased.

Advantageously, the optical axis is aligned in an angular range between and 20 °, preferably between 1 ° and 17.5 °, more preferably between 1 ° and 15 °, relative to the surface normal.

[31] In particular, when the primary optics is adapted to forward only substantially parallel incident on the measuring device light rays to the diffuser, the measuring device can be arranged before the measurement at a distance from the measurement object, the distance a maximum of 40 cm, preferably a maximum 35 cm, more preferably at most 30 cm. The light input of ambient light into the measuring device associated with such a spaced arrangement has no

Significant effects on the measurement result, as the measuring device does not "pass" obliquely incident light beams and therefore they are not used for the measurement

User-friendliness continues to be particularly advantageous.

Furthermore, such a method may be advantageous in which a plurality of measurements of the test object (6) are made within the scope of a measuring operation, wherein the optical axis of the measuring device in the course of performing the individual measurements in different angular positions relative to the surface normal of

Target is aligned. The individual measurements can be carried out very quickly and simply and together lead to a kind of "average value" for the actual color values of the measurement object to be determined a particularly high accuracy possible.

embodiments

[33] The measuring device according to the invention is described below with reference to

Embodiments, which are illustrated in the figures, explained in more detail. It shows: Page 9 of 19

1 shows a schematic cross section through a first invention

Measuring device,

2 shows a cross section through a quartz glass diffuser,

3 shows a cross section through an integral multiple spectral sensor, FIG. 4 shows a cross section through a second measuring device according to the invention and FIG

5 shows a cross section through a third measuring device according to the invention.

[34] A first embodiment shown in FIG

This comprises a primary optics 2, a diaphragm 3, a diffuser 4 and a sensor unit 5. The individual components of the measuring device 1 are arranged symmetrically with respect to an optical axis 21. An input aperture of the measuring device 1 is by means of a housing 20 of a non-illustrated

Hand colorimeter limited, in which the measuring device 1 is installed.

In this position shown in FIG. 1, the measuring device 1 is in its measuring state in which it is used for detecting light beams 7 emanating from a measuring object 6. The housing 20 delimits a measuring surface 18 of the measuring object 6, from which light beams 7 are detected by means of the measuring device 1 according to the invention. In Figure 1 and in the other figures 2 to 5 light beams 7 are graphically illustrated by arrows. [36] The measuring device according to FIG. 1 uses a primary optic 2 which has a continuous lens body 29 in the form of an aspherical lens 15. This is designed here as a TIR collimator lens. This leads to that on the part of the

Measurement object 6 in the lens 15 entering light rays at least partially on an inner surface 9, which limits the transition from the lens 15 to the ambient air, completely reflected and thereby deflected inwardly toward the optical axis 21. In this case, the aspherical lens 15 has a recess 30 in an end region facing away from the measurement object 6. This has the consequence that the light rays 7 flowing through the lens 15 are broken away from the solder 28 at surfaces 9 at which the lens 15 adjoin one another to the recess 30. This can be seen particularly clearly in FIG. 1 with reference to the illustrated arrows.

[37] On a side of the primary optics 2 facing away from the measuring object 6, the diaphragm 3 is arranged, which limits the angle of incidence of the light beams 7. In particular, the primary optic 2 shown is formed almost exclusively to the optical axis 21 Page 10 of 19 parallel to the primary optics 2 entering light rays 7 reach the diffuser 4. The latter is viewed in the direction of radiation of the light rays 7, viewed immediately behind the diaphragm 3. By means of the diffuser 4, which is arranged here in front of a focal plane of the lens 15, light passing through the diaphragm 3 can be homogenized. The diffuser 4 is formed here by quartz glass. It has a rear exit surface 10, from which light is emitted from the diffuser 4. Immediately behind the diffuser 4 is the

Sensor unit 5 is arranged, which is formed here in the form of an integral multiple spectral sensor. The sensor unit 5 has a sensor surface 11 facing the exit surface 10 of the diffuser 4. A distance between the exit surface 10 of the diffuser 4 and the sensor surface 11 of the sensor unit 5 is approximately 0.5 mm in the example shown. 1, it can be seen particularly clearly that the sensor unit 5 can be arranged "directly" behind the diffuser, without the need for secondary optics or the like, and it is understood that an overall length 27 of the measuring device 1 is particularly short in this way can fail.

[38] The diffuser 4 here has a thickness 14 of 0.5 mm and a diameter 23 of 3 mm. It is formed with a circular cross-section and thus has a

Volume of about 3.5 mm ³ . The diffuser 4 has in its interior a plurality of scattering centers 22, at which light rays 7 entering it are scattered. This type of scattering causes the light rays after Transluzens at the exit surface 10 of the diffuser 4 evenly emerge from the latter according to a Lambert radiator. A distribution of the light radiation after emerging from the exit surface 10 can be taken from the diagram shown in FIG. 2, wherein the axis 24 describes the radiation intensity of the light emitted by the exit surface 10 as a function of the emission angle.

[39] A sensor unit 5, which according to the invention of an integral

Multi-spectral sensor is formed, is shown by way of example in Figure 3. The sensor unit 5 shown there is formed by an integral RGB sensor which has a total of 19 individual sensors 25 which are integrated on a chip substrate. Each of these sensors 25 comprises three sub-areas 8, one of the sub-areas 8 being designed to detect green, red and blue light. Overall, the sensor unit 5 has a hexagonal shape, wherein the individual sensors 25 are each hexagonal. A diameter 26 of the sensor unit 5 has approximately 3 mm here. The thus formed

Sensor unit has a high measurement reliability and leads only to low

Color interference effects. In addition, a separate arrangement of color filters is not Page 11 of 19 required; these are each integrated directly into the respective sensor 25. The sensor unit 5 is correspondingly compact.

[40] Another embodiment shown in FIG. 4 has one

Secondary optics 12 in the form of a light guide on. Furthermore, the primary optics 2 of the measuring device 1 shown is designed differently than that according to FIG. 1. This will be dealt with separately later. The secondary optics 12 of the measuring device 1 according to FIG. 4 can be used, for example, to direct light emitted by the diffuser 4 to a remote sensor unit 5. In addition, the secondary optics 12 make it possible to adapt the aperture of the diffuser 4, which is delimited by the diaphragm 3, to the aperture of the sensor unit 5. For this purpose, it is necessary that a cross section of the light guide is adapted to the respective apertures at the respectively corresponding ends on the diffuser 4 and the sensor unit 5.

The primary optic 2 of the measuring device 1 according to FIG. 4 is here formed by a total of three lenses 16, 17, 19, with a convex lens 16 with positive refractive power combined with a concave lens 17 with negative refractive power than more coherent

Lens body 29 is executed. These two lenses 16, 17 are matched with respect to their common surface 9 and their dispersions such that the lens body 29 is suitable for the correction of both the chromatic and the spherical aberration. Viewed in the direction of radiation of the light beams 7, the lenses 16, 17 are followed by the further lens 19, which has a positive refractive power and thereby further focuses the light beams 7 impinging on them. By combining the lens body 29 formed by the lenses 16, 17 with the further lens 19 with a positive refractive power, an overall length 27 of the measuring device 1 can be reduced particularly well, while at the same time display errors are corrected by the action of the lens body 29. As an alternative to the realization of a particularly short overall length 27, this embodiment also makes it possible, while maintaining a "normal" length 27, to detect a comparatively large measuring surface 18 and thereby, despite a small size

Aperture diameter to achieve a comparatively large aperture of the measuring device 1.

[42] In the example shown, the diffuser 4 is arranged behind the focal plane of the primary optics 2. Incidentally, the primary optics 2 is overall tuned together with the diaphragm 3 such that almost exclusively such light beams 7 reach the diffuser 4, which are aligned at least substantially parallel to the optical axis 21.

In a modification of the embodiment according to FIG. 4, the measuring device 1 according to FIG. 5 has a different secondary optic 12, here of a gradient optics 13 Page 12 of 19 is formed. The secondary optics 12 is adjoined off the diffuser 4 by a sensor unit 5, which is also formed here by an integral multiple spectral sensor. Furthermore, it is shown by way of example that the measurement object 6 is arranged at an angle relative to the optical axis 21 of the measuring device 1. A surface normal of the measuring object 6 includes here with the optical axis 21 an angle 31 of about 5 °.

[44] It is understood that the individual features of the embodiments described above can basically act independently of each other positively and are not limited to the combinations disclosed herein. A "free combination" of the individual features of different embodiments is readily conceivable, if the technician must appear technically reasonable and possible.

Page 13 of 19

LIST OF REFERENCE NUMBERS

1 measuring device

2 primary optics

3 aperture

4 diffuser

5 sensor unit

6 measuring object

7 light beam

8 partial area

9 area

10 exit surface

11 sensor surface

12 secondary optics

13 gradient optics

14 thickness

15 aspherical lens

16 spherical lens

17 spherical lens

18 measuring area

19 lens

20 housing wall

21 optical axis

22 scattering center

23 Diameter of the diffuser

24 axis

25 sensor

26 Diameter of the sensor unit

27 length Page 14 of 19 Lot

lens body

recess

angle

Claims

Page 15 of 19 claims

1. Opto-electronic measuring device (1) for a color measuring device, in particular a hand-held colorimeter for use on screens, comprising

at least one primary optic (2),

at least one aperture (3),

at least one diffuser (4) and

at least one sensor unit (5),

wherein the measuring device (1) is designed such that in the presence of the

Measuring device (1) in a measurement state of a measurement object (6) emanating light beams (7) on the primary optics (2) meet and by means of the primary optics (2) are at least partially bundled,

wherein the diaphragm (3), viewed in the radiation direction of the light beams (7), is arranged in front of the diffuser (4) and limits an angle of incidence of the light beams (7),

wherein the light beams (7) are homogenizable by means of the diffuser (4), so that they can be conducted uniformly onto the sensor unit (5) starting from the diffuser (4),

wherein the light beams (7) are convertible by means of the sensor unit (5) into electrical signals,

wherein the sensor unit (5) is formed by an integral multi-spectral sensor which has at least three partial surfaces (8) for detecting respectively different spectral components,

characterized in that

the primary optic (2) has at least one coherent lens body (29) which has two regions of different dispersion and / or a total of at least three refractive and / or reflective surfaces (9).

2. Measuring device () according to claim 1, wherein the lens body (29) of the

Primary optics (2) only a portion of a dispersion, characterized in that the lens body (29) by a TIR collimator lens with at least three reflective and / or refractive surfaces (9) is formed. Page 16 of 19

3. Measuring device (1) according to claim 1, wherein the lens body (29) has two

Having regions of different dispersion, characterized in that the lens body (29) is formed by a two-lingual Achromaten, wherein the two lenses (16, 17) of the achromatic are directly connected to each other, wherein one of the lenses (16, 17) has a positive and the other lens (17) have a negative refractive power.

4. Measuring device (1) according to one of claims 1 to 3, characterized in that the primary optics (2) is formed by a non-imaging optics, wherein preferably the diffuser (4) outside a focal plane of the primary optic (2), more preferably of the primary optic (2) seen from this side of the focal plane.

5. Measuring device according to one of claims 1 to 4, characterized in that the primary optics (2) is tuned in such a way and with the diaphragm (3)

cooperates, that at least substantially only such light beams (7) reach the diffuser (4), the at least substantially parallel to an optical axis (21) of a first deflection or deflection

Measuring device (1) run.

6. measuring device (1) according to one of claims 1 to 5, characterized in that the sensor unit (5) is formed by an integral RGB sensor, the three sub-areas (8) for detecting a respective red, green and blue spectral component having.

7. Measuring device (1) according to one of claims 1 to 6, characterized in that an outlet surface (10) of the diffuser (4) and a sensor surface (11) of the sensor unit (5) have an at least substantially, preferably completely, matching aperture ,

8. Measuring device (1) according to one of claims 1 to 7, characterized by a secondary optics (12), viewed in the radiation direction of the light beams (7) between the diffuser (4) and the sensor unit (5) is arranged, wherein of the diffuser (4) outgoing light beams (7) by means of

Secondary optics (12) on the sensor unit (5) are conductive.

9. measuring device (1) according to claim 8, characterized in that the

Secondary optics (12) comprises at least one gradient optics (13). Page 17 of 19

10. Measuring device (1) according to one of claims 1 to 9, characterized in that the primary optics (2) comprises at least one further lens (19) having a positive internal force, wherein the further lens (19) preferably the contiguous lens body ( 29) is connected downstream.

11. Measuring device (1) according to one of claims 1 to 10, characterized

in that a ratio between a measuring surface (18) of the measuring object (6) which can be detected by means of the measuring device (1) and a sensor surface (1) of the sensor unit (5) is at least 1: 150, preferably at least 1: 125 preferably at least 1: 100.

12. A method of operating a measuring device (1) according to one of claims 1 to 1 1, comprising the following method steps:

a) The measuring device (1) is relative to the measuring object (6)

aligned, so that from the measuring object (6) outgoing light beams (7) by means of the measuring device (1) can be detected.

b) A measurement of the measuring object (6) is carried out, wherein

Light beams (7) by means of the measuring device (1) detected on the

Color to be analyzed.

c) Actual color values determined in this way are compared with nominal color values of the light beams (7) emitted by the test object (6).

d) the measurement object (6) is driven at least indirectly in order to change its color rendering in such a way that the actual color values change in the direction of the desired color values,

characterized by the following process step:

e) Before carrying out the measurement, an optical axis (21) of the measuring device (1) is aligned rotated relative to a surface normal which is perpendicular to an emission surface of the measurement object (6), so that the optical axis (21) and the surface normal together Include angles greater than 0 °.

13. The method according to claim 12, characterized in that the optical axis (21) is aligned in an angular range between 1 ° and 20 °, preferably between and 17.5 °, more preferably between and 15 °, relative to the surface normal. Page 18 of 19

14. The method according to claim 12 or 13, characterized in that the

Measuring device (1) before the measurement at a distance from the measuring object (6) is arranged, wherein the distance is not more than 40 cm, preferably at most 35 cm, more preferably at most 30 cm.

15. The method according to any one of claims 12 to 14, characterized in that by means of the measuring device (1) in the context of a measuring operation, a plurality of measurements of the measuring object (6) are made, wherein the optical axis (21) of the measuring device (1) is aligned in the course of performing the individual measurements in different angular positions relative to the surface normal of the measurement object (6).