DE2905727A1 - ARRANGEMENT FOR MEASURING THE PROPERTIES DETERMINING THE GLOSS POWER OF SURFACES - Google Patents

Description

1530

Patent attorneys

Dipl. Ing. Ηβΐυ; -Jürgen Müller 0 Q fj C 7 O 7

Dr. rer. nat. Thomas Berendt * Ό ν J f LI

Dr. - Ing.Hans Leyh "* 3 - Luclle-Grahn-StroBe 3d D 8 Munich 80

Arrangement for measuring the properties that determine the glossiness of surfaces

VIANOVA KUNSTHARZ AKTIENGESELLSCHAFT, A-8402 Werndorf near Graz

1530

The invention relates to an arrangement for measuring the gloss power of surfaces, especially of organic coatings, determining optical properties. By the invention Arrangement, a simplified and more sensitive measurement of those properties of surfaces is possible, which produce the subjective impression of "shine" in a viewer under certain lighting conditions.

The decisive factor for the gloss is the quality of the effective interfaces for reflection and scattering. If you illuminate a surface with a preferably parallel one Light beam, the light that is regularly reflected and diffusely scattered from the surface contains information about the surface Nature.

Devices that show the intensity distribution of the scattered and reflected Allowing light to be measured over a more or less large angular range are known as goniophotometers. From DE-PS 24 54 644 and AT-PS 334 657 it is also known that for the characterization of high-gloss surfaces in There is already a range of angles with regard to course disturbances and haze of sheen of about one or four times the full width at half maximum of the goniophotometer is sufficient and that it is easier in these cases the measuring diaphragm moves with rigid measuring optics instead of pivoting the entire measuring optics over the desired angular range.

For a summary assessment of the glossiness, it is customary to use Used reflectometer, a type of device which, inter alia. is described in detail in DIN 67 530.

Devices showing the special properties of goniophotometers and reflectometers are also known and are called gonioreflectometers (see e.g. Technical Information of Vianova Kunstharz Aktiengesellschaft: gonioreflectometer GR-COMP.). Such a combined goniophotometer and reflectometer (Gonioreflectometer) for differentiated quantitative

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Assessment of the glossiness of surfaces, in particular organic coatings, does not become the state of the art in that either belonging Austrian patent application A 8794/77.

All these known devices have in common that they consist of geometrical-mechanical For reasons, no smaller measuring angle (based on the surface normal to the measuring object) than about 20 ° is achieved can be.

The object of the present invention was to also apply the gonioreflectometer principle by means of a special arrangement 0 ° measuring angle to expand, thereby not only a simpler structure with a smaller number of costly, one on top of the other coordinated optical components should be achieved, but at the same time also the one linked to the angular position 0 °, highest possible sensitivity in differentiating shinier Surfaces.

In the present invention, the above-mentioned object was also based on the type of arrangement which is completely new for such measuring devices fixed optics and moving measuring diaphragm. and measuring optics arranged coaxially in essential parts and directed at 0 ° (perpendicular) onto the measuring surface are.

The present invention therefore relates to an arrangement for measuring the gloss of surfaces, in particular of organic coatings determining optical properties, with fixed optics and moving measuring diaphragm by one below 0 ° (based on the normal to the measuring surface) Coaxial lighting and measuring optics directed at the measuring surface.

The various embodiments of the invention Arrangements differ mainly according to the type of separation of the measuring beam path from the common optics

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according to Figures 1 to 5:

Arrangement with a common aperture and two physical beam splitters

Arrangement with a fixed and a movable diaphragm and two physical beam splitters

Arrangement with a composed of sub-bundles Light guide

Different fiber optic configurations

Arrangement with a fixed screen, two beam splitters and a light guide

Thus, according to FIG. 1, there is a particularly advantageous arrangement of a light source (1), a single moving diaphragm (2), which forms the illumination and measurement aperture at the same time, a beam splitter (3) located between the light source and the diaphragm for reflecting out of the measuring beam path on the measuring detector (7), a further beam splitter (4) located after said diaphragm, the conducts a small part of the luminous flux used for lighting onto the reference detector (8), and finally out of the common lens (5), its rear focal plane in the diaphragm (2) and its front focal plane in the measuring surface (6) lies.

Thanks to the special arrangement of the beam splitters, these arrangements not only permit measurements with a particularly low level of extraneous light the remission properties of the measuring surface with precise detection of the luminous flux passing through the diaphragm by means of a reference detector, but also an effective angular range of the diaphragm position that is twice as large compared to conventional arrangements, because the image of the diaphragm falls back on itself after reflection on the measuring surface and moves in the opposite direction to it.

To record a meaningful remission curve, the Aperture preferably be slit-shaped and in the direction of its narrower, the essential opening of the measuring beam

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determining side can be moved linearly.

Is a separation of lighting and lighting for structural reasons A measuring diaphragm is necessary (e.g. because of different sizes or shapes of these diaphragms), a different arrangement according to FIG. 2 is required particularly advantageous, those from their own, fixed Illumination diaphragm (21) and a movable measuring diaphragm (22), the luminous flux reaching the measurement via the between the objective (5) and the beam splitter (4) (for the reference detector), the second beam splitter (31) is reflected. The separate position of the beam splitters (4, 31) offers the advantage of a perfect separation between the illumination and measurement beam path.

In a further arrangement according to the invention (FIG. 3) takes over a flexible light guide composed of individual fibers and consisting of several sub-bundles (93, 94) (9) both the beam splitter functions and the diaphragm functions. The end (92) of the light guide directed towards the objective (5) and movable transversely to the optical axis forms both the effective illumination and measuring diaphragm, a partial bundle (94) opening into this end (92) leads to the measuring detector (7), another partial bundle (93) opening into the end (91) facing the light source leads to the reference detector (8).

This type of geometric beam splitting has the advantage of providing the best possible separation between the illumination and measurement beam path with a minimum number of optical components.

Particularly advantageous embodiments of the geometric beam splitting and thus the composition of the lens-side Optical fiber ends (92) made up of partial bundles are shown schematically in FIG. 4. The partial bundles can be made by uniform Distribution of the individual fibers (920, 921) be summarized, which z. B. for the combination of lighting bundles and central measuring bundle comes into question, or the partial bundles

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can be formed into concentric rings (922, 923), which is particularly useful for detecting over diffused light in certain angular ranges. Likewise, there is a stringing together of rectangularly delimited partial bundles (924, 925, 926, 927) possible, for example the first section (924) of the illumination, the second (925) of the measurement of the directly reflected light and another (926, 927) for measuring other parts of the intensity distribution of the the measuring surface of reflected light can serve. While these partial bundles thus form a common end face on the objective side (92) are combined, they run out in separate arms (910, 911, 912, 913), each of which leads to its own detectors or lead to the lighting device.

This type of replacement of mechanical screens by light guides offers a particular advantage over conventional ones Arrangements the practically complete stringing together of partial bundles that act like diaphragms, which then become separate Detectors can be guided. This makes it possible, instead of a sequential measurement of an intensity distribution by moving a diaphragm, the same information is obtained through parallel measurement by means of seamlessly strung together Obtain aperture zones in a shorter time with less mechanical effort.

Finally, the combination shown in FIG. 5 results therefrom of physical beam splitters (4, 31) and a mechanical diaphragm (21) with one of the previously described ones Light guide arrangements, the combined end (92) of the light guide (9) replacing the moving diaphragm (22) occurs in the arrangement of FIG. 2, whereby the advantages of parallel measurement by means of a light guide arrangement are combined with the the advantages of an arrangement with separate diaphragms described above.

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Claims (6)

1530 Patent claims: 1Λ Arrangement for measuring the optical properties that determine the gloss of surfaces, especially organic coatings, with fixed optics and moving measuring diaphragm, characterized by coaxial lighting and measuring optics directed at 0 ° (relative to the normal to the measuring surface) on the measuring surface . 2. Arrangement according to claim 1, consisting of a light source (1), a common, moving, preferably gap-shaped Measuring and illumination diaphragm (2), a beam splitter (3) in front of this diaphragm for deflecting the measuring beam path onto one Measuring detector (7), another beam splitter (4) located after the diaphragm for a reference detector (8), and one Objective (5), in whose rear focal plane the diaphragm (2) and in whose front focal plane the measuring surface (6) lies. 3. Arrangement according to claim 1, consisting of the light source (1), an illumination diaphragm (21), the one located after this diaphragm Beam splitter (4) for the reference detector (8), one second beam splitter (31) arranged after this beam splitter for separating the measuring beams which are moved by a Measuring diaphragm (22) reach the measuring detector (7), and the lens (5), in the rear focal plane of which the two diaphragms (21, 22) and the measuring surface (6) lie in its front focal plane. 4. Arrangement according to claim 1, consisting of the light source (1), a flexible, composed of several individual fibers Light guide (9) whose side (91) facing the light source is fixed relative to it and whose side facing the objective (5) and the side (92) directed towards the measuring surface (6) forms both the effective illumination and measuring diaphragm and is uniaxial or biaxial is movable transversely to the optical axis and its individual fibers from the lighting side (91) and / or from the object side (92) are combined to form various sub-bundles (93, 94) which form the associated detectors (7, 8). 809846/0544 ORIGWAL INSPECTED 1530 5. Arrangement according to claim 4, characterized by one composed of several sub-bundles (910, 911, 912, 913) flexible light guide (9), the partial bundles on the objective side End surface (92) combined by uniform distribution of the individual fibers (920, 921) or in concentric form Rings are lined up in a row (922, 923) or placed close together in rectangular areas (924, 925, 926, 927), but at the other end of the light guide (9) run out in separate arms (910, 911, 912, 913). 6. Arrangement according to claim 3, characterized by a with its front side (92) at the point of the measuring diaphragm (22) lying, movable light guide (9), its on different Detectors (70, 71, 72, 73) opening partial bundles (910, 911, 912, 913) on the front side (92) to form annular (920, 921, 922, 923) or rectangular (924, 925, 926, 927) zones are combined. $ 09845/0544