APPARATUS AND METHOD FOR INSPECTING SURFACES WITH WAVELENGTH ANALYSIS

Abstract

An apparatus for examining surface properties of lacquered surfaces, in particular of motor vehicles, having a first illumination device which illuminates a surface to be examined at a first illumination angle, having a second illumination device which illuminates the surface at a second illumination angle, having a first sensor device which records radiation reflected and/or scattered by the surface illuminated by the second illumination device at a first recording angle and outputs at least one value which is characteristic of the radiation reaching the sensor device from the surface, wherein the apparatus has a radiation analysis device which analyses radiation scattered and/or reflected by the surface with regard to its wavelength.

Claims

1. An apparatus for examining surface properties of lacquered surfaces, having a first illumination device which illuminates a surface to be examined at a first illumination angle, having a second illumination device which illuminates the surface a second illumination angle, having a first sensor device which detects radiation reflected and/or scattered by the surface illuminated by the second illumination device at a first recording angle, wherein the apparatus has a radiation analysis device (which analyses radiation scattered and/or reflected by the surface with respect to its wavelength.

2. The apparatus according to claim 1, wherein the radiation analysis device comprises a spectrometer.

3. The apparatus according to claim 1, wherein the radiation analysis device is arranged such that it records the radiation irradiated onto the surface by at least one of the illumination devices and scattered and/or reflected by the surface.

4. The apparatus according to claim 1, wherein the radiation analysis device is a component of the sensor device.

5. The apparatus according to claim 1, wherein the apparatus has an integrator device which integrates a signal output by the radiation analysis device.

6. The apparatus according to claim 1, wherein the apparatus has a third illumination device which is arranged with respect to the surface at a third illumination angle-fa.

7. The apparatus according to claim 1, wherein at least one illumination angle is between 30 and 60, preferably between 35 and 55, preferably between 40 and 50 and particularly preferably at 45, and/or in that at least one illumination angle is greater than 60, preferably greater than 65, preferably greater than 70, preferably greater than 75 and particularly preferably greater than 80.

8. The apparatus according to claim 1, wherein the radiation analysis device is suitable and intended for analyzing radiation which has been irradiated onto the surface by the first and/or the third illumination device and has been scattered by the surface with respect to its wavelength.

9. The apparatus according to claim 1, wherein the apparatus has a fourth illumination device, which is arranged with respect to the surface at a fourth illumination angle.

10. The apparatus according to claim 1, wherein at least one illumination device is suitable and intended for irradiating radiation of different wavelengths onto the surface.

11. A method for examining surface properties of lacquered surfaces, wherein a first illumination device illuminates a surface to be examined at a first illumination angle, and wherein a second illumination device illuminates the surface at a second illumination angle, and a first sensor device records radiation reflected and/or scattered by the surface illuminated by the second illumination device at a first recording angle and outputs at least one value which is characteristic of the radiation reaching the sensor device from the surface, wherein a radiation analysis device analyzes radiation scattered and/or reflected by the surface with regard to its wavelength.

12. The method according to claim 11, wherein both the value determined by the sensor device and data recorded by the radiation analysis device are taken into account for an evaluation of the surface properties.

13. The method according to claim 11, wherein an illumination device irradiates radiation onto the surface and the radiation analysis device records the radiation irradiated by the illumination device and reflected by the surface.

14. The method according to claim 11, wherein the radiation analysis device analyzes the radiation by a spectrometer.

15. The method according to claim 11, wherein a third illumination device illuminates the surface at a third angle.

Description

[0056] Further advantages and embodiments are shown in the attached drawings:

[0057] In the drawings:

[0058] FIG. 1 shows a schematic representation of the apparatus according to the invention;

[0059] FIG. 2 shows a diagram illustrating the beam analysis;

[0060] FIG. 3 shows a further illustration of an apparatus according to the state of the art;

[0061] FIG. 4 shows a further illustration of the present invention.

[0062] FIG. 1 shows a schematic representation of an apparatus 1 according to the invention, which has a first illumination device 2 that illuminates a surface 10 to be inspected at a first illumination angle a1 or irradiates light at this angle. A sensor device 4 records the radiation scattered or reflected by the illuminated surface and, in particular, the scattered radiation.

[0063] The reference sign 16 indicates a housing within which the described components are arranged. Preferably, an inner wall of this housing is designed to absorb radiation. The reference sign O indicates an opening through which the surface 10 can be illuminated and/or through which the surface can be observed.

[0064] The reference sign 12 identifies a second illumination device, which also irradiates radiation onto the surface at a predetermined angle a2. This predetermined angle is 45 here. The reference sign 14 identifies a radiation analysis device which records the radiation irradiated onto the surface by the illumination device 12 and reflected by the surface and analyzes it with regard to its wavelength. The radiation analysis device also functions as the sensor device 4.

[0065] The reference sign 6 indicates a further illumination device which illuminates the surface at a very flat angle. The radiation analysis device 14 preferably records radiation from the surface illuminated by the illumination device 6 (or records radiation which has been irradiated onto the surface by the illumination device 6 and has been reflected and/or scattered by the surface and in particular scattered). It is thus proposed that the surface 10 is illuminated at different angles and that the radiation reflected and/or scattered by the surface is recorded by the radiation analysis device in each case.

[0066] The reference sign 8 indicates a further illumination device, which here also illuminates the surface 10. The radiation analysis device 14 also records the radiation irradiated by the further illumination device and reflected and/or scattered by the surface.

[0067] In the embodiment shown here, the surface is therefore illuminated from three different angles and the radiation analysis device records the radiation scattered by the surface in each case and carries out a spectral analysis of this radiation.

[0068] The reference sign a1 indicates the first incidence or illumination angle (relative to the vertical direction) at which the first illumination device 2 illuminates the surface 10. This angle is 30 in this case. The reference sign b1 indicates the fourth incidence angle at which the illumination device 8 illuminates the surface 10. This is 0 here, so the illumination is perpendicular to the surface 10. However, it is also possible that this illumination is not at 0 but at a predetermined angle, which is preferably less than 20, preferably less than 10 (relative to the perpendicular direction).

[0069] The reference sign a2 identifies the second incidence and/or illumination angle at which the second radiation device 12 emits radiation onto the surface 10. This second incidence and/or illumination angle is 45 here. The reference sign b2 indicates the second recording angle at which the radiation analysis device 14 and the sensor device are arranged relative to the surface 10 or at which the reflected radiation is recorded. In this case, this angle is 45 relative to the surface 10.

[0070] The reference sign a3 indicates a third incidence and/or illumination angle at which the third radiation device 6 illuminates the surface 10. In this case, this is approximately 70. Optionally, a fourth radiation device can also be provided, which illuminates the surface at a further incidence and/or illumination angle.

[0071] The reference sign 20 schematically identifies a control device which causes the illumination of the surface from the different angles to take place with a time delay. In addition, the apparatus preferably has a storage device (not shown) in which data recorded by the radiation analysis device are stored.

[0072] The sensor device 4, which is used to detect the radiation reflected from the surface 10, also uses the radiation analysis device, but an integrator device (not shown) again integrates the recorded spectrum over the wavelengths and thus outputs an integrated value for the intensity.

[0073] FIG. 2 illustrates the gloss measurement process in more detail. Preferably, the second illumination device 12 irradiates radiation onto the surface 10 at an angle of 45 (relative to the vertical direction) and the radiation analysis device records the radiation reflected from the surface at the reflection angle (here)45. Preferably, the illumination device emits standard light, in particular D65 standard light. Furthermore, the illumination device preferably emits directed radiation onto the surface.

[0074] The sensor device 4 records the reflected radiation. The radiation analysis device 14 can analyze the radiation impinging on it more precisely, preferably with regard to its wavelength, and can preferably output an intensity distribution in a wavelength range of between 300 nm and 900 nm, preferably between 350 nm and 800 nm and particularly preferably between 400 nm and 700 nm. However, an integrated value of the intensity over the wavelengths is output as the measured value for this measurement. Due to this integration, the radiation analysis device is also referred to here as the sensor device 4.

[0075] FIG. 3 shows an apparatus according to the internal prior art of the applicant. Here again, the illumination devices 2, 6 and 8 can be seen, each of which emits radiation onto the surface, and the sensor device 4, which records the radiation reflected and/or scattered by the surface.

[0076] FIG. 4 shows a schematic representation of an apparatus 1 according to the invention. An illumination device 12 is also provided here, which illuminates the surface, in this case at an angle of 45. Preferably, this illumination device is a white light LED. Preferably, this illumination device is arranged in a light trap 13. A lens device (not shown) for collimation can be arranged in front of this illumination device. This illumination device 12 is preferably positioned at the angle of the specular reflection in the direction of the radiation analysis device 14 or the spectrometer.

[0077] The reference sign 14 thus refers to the radiation analysis device, which however also functions as a sensor device 4 at the same time. The device 14 has a spectrometer, wherein the reference sign 15 refers to a dispersive element.

[0078] This allows the incident radiation to be analyzed over many wavelengths.

[0079] In addition, the spectral analysis device also has an integrator device 17, which integrates the signal from the spectral analysis device output via all channels. This integration takes place in particular via the radiation emitted by the illumination device 12 and reflected onto the radiation analysis device 14.

[0080] In this way, its very simple and inexpensive gloss measurement can be realized, which can supplement the color measurement by using the spectral analysis device for gloss measurement purposes, in particular without disturbing the actual color measurement in any way. The available, spectrally resolved gloss values allow all the freedom of further computational processing, namely the calculation of a standard-compliant (v-lambda-weighted) gloss value or the output of other color-dependent (user-defined) gloss values. In particular for automotive lacquerings with a base coat (possibly with effect pigments) and a clear coat finish, both the influence of the gloss level of the clear coat on the color measurement of the base coat and the influence of the color of the base coat on the gloss measurement of the clear coat can be decoupled metrologically.

[0081] It can be seen here that, in particular, numerous lenses 22 are also integrated into the apparatus. These lenses are arranged at least partially in front of the radiation devices or illumination devices 2, 6 and 8.

[0082] Radiation channels 24 are arranged between these lenses 22 and the radiation devices (only one designated).

[0083] An aperture is preferably arranged between the second radiation and/or illumination device 12 and the surface 10 (i.e. in the beam path between the radiation and/or illumination device 12 and the surface 10) in order to collimate the beam path. Preferably, the second illumination device is arranged within a beam trap 13. The reference symbol 34 indicates a further aperture.

[0084] The applicant reserves the right to claim all features disclosed in the application documents as being essential to the invention, provided that they are new, either individually or in combination, compared with the prior art. It should also be noted that the individual figures also describe features which may be advantageous in themselves. The skilled person will immediately recognize that a certain feature described in a figure can also be advantageous without the adoption of further features from this figure. Furthermore, the skilled person recognizes that advantages can also result from a combination of several features shown in individual figures or in different figures.