Device and method for the determination of the quality of surfaces

• US 7,391,518 B1
• Filed: 06/30/2000
• Issued: 06/24/2008
• Est. Priority Date: 07/02/1999
• Status: Expired due to Fees

• Current Assignee: BYK-Gardner GmbH (Susanne Klatten, MBA)
• Original Assignee: BYK-Gardner GmbH (Susanne Klatten, MBA)
• Inventors: Schwarz, Peter, Sperling, Uwe
• Primary Examiner(s): Lauchman; L. G.
• Assistant Examiner(s): Stock, Jr.; Gordon J
• Application Number:
  US09/607,827
• Time in Patent Office: 2,916 Days
• Field of Search: 25055901-55912, 356/402, 356600-613, 356/403, 356/405, 356/406, 356/416, 356418-423, 356/425, 356445-448, 356/239.1, 356/239.7, 356/237.2, 356/73
• US Class Current: 356/446
• CPC Class Codes: G01B 11/30 for measuring roughness or irregularity of surfaces
• CPC Class Codes: G01J 2003/1282 Spectrum tailoring
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01J 3/2803 using photoelectric array detector
• CPC Class Codes: G01J 3/465 taking into account the colour perception of the eye; using tristimulus detection
• CPC Class Codes: G01J 3/501 Colorimeters using spectrally-selective light sources, e.g. LEDs
• CPC Class Codes: G01J 3/51 using colour filters
• CPC Class Codes: G01N 21/255 Details, e.g. use of specially adapted sources, lighting or optical systems

Abstract

The present invention relates to a device and method for making quantified determinations of the quality of surfaces and wherein the device comprises an optical system with a first optical means and a second optical means as well as a control and evaluation means and an output (display) means. Said first optical means comprises an illuminating means having at least one LED as its light source and serves the function of illuminating the measurement surface at a predetermined angle. Said second optical means is likewise directed at a predetermined angle to the measurement surface and receives the reflected light. A photo sensor of said second optical means emits an electrical measurement signal which is characteristic of said reflected light.

The light emitted from the illuminating means is configured such that its spectral characteristic comprises blue, green and red spectral components in the visible light spectrum. A filter means is arranged in the path of radiation between the light source and the photo sensor and which changes the spectral characteristics of the incident light so as to approach a predetermined spectral distribution. The control and evaluation means control the measurement sequence and evaluate the reflected light, deriving therefrom at least one parameter which is characteristic of the surface.

Claims

1. A device for making quantified determinations of characteristic parameters of a surface, the characteristic parameters being selected from the group of gloss, haze, and distinctness of image, comprising:

at least one optical system having;

a light diode emitting an emitted light at the surface so that said emitted light hits the surface at a predetermined angle of incidence, said emitted light having a light intensity over the entire visible spectral range;

a lens parallelizing said emitted light before said emitted light hits the surface;

at least one photo sensor receiving a reflected light from the surface at a predetermined angle of reflection, said photo sensor generating a signal based on said reflected light, wherein said predetermined angle of incidence and said predetermined angle of reflection are mirror symmetrical to each other with respect to a normal to the surface;

filter means arranged in a light path between said light diode and said at least one photo sensor and for adapting a spectrum such that an aggregate spectrum of said light diode, said at least one photo sensor, and said filter means corresponds to an aggregate of daylight spectrum and eye sensitivity;

a lens for focusing said reflected light into a light beam, wherein said light beam impinges on said at least one photo sensor; and

evaluation means for determining the gloss, haze, and distinctness of image of the surface based on said signal, said signal corresponding to portions of said reflected light, wherein said at least one optical system comprises three optical systems, and wherein said predetermined angle of incidence and reflection is different for each of said three optical systems.

2. The device according to claim 1, wherein said predetermined angles of incidence and reflection angles selected from the group consisting of 0°

, 10°

, 15°

, 20°

, 30°

, 45°

, 60°

, 75°

, 80°

, and 85°

.

3. The device according to claim 1, wherein said emitted light comprises at least one light strip.

4. The device according to claim 1, further comprising a temperature device for determining a temperature of each of said light diode and said at least one photo sensor so that a temperature-corrected determination of characteristic parameters can be made.

5. The device according to claim 1, further comprising a measurement wheel positionable on the surface to maintain a constant spacing therefrom during movement of the device relative to the surface.

6. The device according to claim 1, wherein said at least one photo sensor comprises at least three photo sensitive elements.

7. The device according to claim 1, further comprising a measurement cycle of less than 0.2 seconds.

8. The device according to claim 1, wherein said light diode comprises a light emitting member, said light emitting member having a precisely defined position within the light diode, wherein said precisely defined position does not vary over time.

9. The device according to claim 1, wherein each of said predetermined angles of incidence do not vary over time.

10. The device according to claim 1, further comprising a scatter disk arrangement positioned with respect to said light diode so that said emitted light homogeneously illuminates the surface.

11. The device according to claim 1, wherein said three optical systems are arranged in such a way that all three of said three optical systems essentially illuminate a same measurement point.

12. The device according to claim 1, further comprising a plurality of photo sensors arranged adjacent to one another.

13. The device according to claim 1, wherein at least a portion of said emitted light comprises a light pattern.

14. The device according to claim 13, wherein said light pattern comprises at least one light/dark edge.

15. The device according to claim 13, wherein said light pattern is a pattern selected from the group consisting of a grid form, a cross-mesh form, an ellipse form, and a circular form.

16. A method for making quantified determinations of the gloss, haze, and distinctness of image of a surface, comprising the steps of:

controlling a light diode to emit an emitted light at the surface so that said emitted light hits the surface at a predetermined angle of incidence, said emitted light having a light intensity over the entire visible spectral range;

parallelizing said emitted light before said emitted light hits the surface;

focusing a reflected light that is reflected from the surface along a predetermined angle of reflection into a light beam having an aggregate spectrum, wherein said angle of incidence and said angle of reflection are mirror symmetrical with respect to a normal to the surface;

arranging a photo sensor so that said light beam impinges onto said photo sensor;

controlling said photo sensor to detect said light beam and to emit an electrical signal based on said light beam;

arranging a filter means in a light path between said light diode and said photo sensor, said filter means filtering said emitted light and/or said reflected light so that an aggregate spectra corresponds to an aggregate of daylight spectrum and eye sensitivity;

determining the gloss, haze, and distinctness of image based on said signal, said signal corresponding to portions of said reflected light;

controlling a second light diode to emit a second emitted light at the surface so that said second emitted light hits the surface at a second predetermined angle of incidence, said second emitted light having a light intensity over the entire visible spectral range, said second predetermined angle of incidence being different from said predetermined angle of incidence;

parallelizing said second emitted light before said second emitted light hits the surface;

focusing a second reflected light that is reflected from the surface along a second predetermined angle of reflection into a second light beam having an aggregate spectrum, wherein said second angle of incidence and second angle of reflection are mirror symmetrical with respect to a normal to the surface, said second predetermined angle of reflection being different from said predetermined angle of reflection;

arranging a second photo sensor so that said second light beam impinges onto said second photo sensor;

controlling said second photo sensor to detect said second light beam and to emit a second electrical signal based on said second light beam;

arranging a second filter means in a second light path between said second light diode and said second photo sensor, said second filter means filtering said second emitted light and/or said second reflected light so that an aggregate spectra corresponds to an aggregate of daylight spectrum and eye sensitivity; and

determining the gloss, haze, and distinctness of image based on said signal and said second signal.

17. The method according to claim 16, wherein determining the gloss haze, and distinctness of image comprises a measurement cycle of less than 0.2 seconds.

18. The method according to claim 16, further comprising arranging a plurality of photo sensors adjacent to one another.

19. The method according to claim 16, further comprising causing relative movement between said light diode and said photo sensor and the surface.

20. The method according to claim 16, wherein said light diode comprises a light emitting member, said light emitting member having a precisely defined position within the light diode, wherein said precisely defined position does not vary over time.

21. The method according to claim 16, wherein said angle of incidence does not vary over time.

22. The method according to claim 16, further comprising positioning a scatter disk arrangement with respect to said light diode so that said emitted light homogeneously illuminates the surface.

23. The method according to claim 16, further comprising causing at least a portion of said emitted light to comprise a light pattern.

24. The method according to claim 23, wherein said light pattern comprises at least one light/dark edge.

25. The method according to claim 23, wherein said light pattern is a pattern selected from the group consisting of a grid form, a cross-mesh form, an ellipse form, and a circular form.