Apparatus and method for measuring optical characteristics of an object

• US 7,403,285 B2
• Filed: 03/21/2005
• Issued: 07/22/2008
• Est. Priority Date: 07/01/1997
• Status: Expired due to Fees

• Current Assignee: RPX Corporation
• Original Assignee: JJL Technologies, L.L.C.
• Inventors: Jung, Wayne D, Jung, Russell W., Loudermilk, Alan R.
• Primary Examiner(s): Nguyen, Tu T
• Application Number:
  US11/085,934
• Publication Number:
  US 20050168742A1
• Time in Patent Office: 1,219 Days
• Field of Search: 356/73, 356/446, 356/402, 356/416, 356/417, 356/419, 250/227.14, 250/227.16
• US Class Current: 356/326
• CPC Class Codes: A61B 2560/0233 Optical standards
• CPC Class Codes: A61B 2562/247 Hygienic covers, i.e. for covering the sensor or apparatus during use
• CPC Class Codes: A61B 5/0088 for oral or dental tissue
• CPC Class Codes: A61C 19/10 Supports for artificial teeth for transport or for comparison of the colour
• CPC Class Codes: G01J 1/04 Optical or mechanical part supplementary adjustable parts
• CPC Class Codes: G01J 1/0411 using focussing or collimating elements, i.e. lenses or mirrors; Aberration correction
• CPC Class Codes: G01J 1/0437 using masks, aperture plates, spatial light modulators, spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 1/0474 Diffusers cavities G01J2001/0481
• CPC Class Codes: G01J 1/06 Restricting the angle of incident light
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0205 Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
• CPC Class Codes: G01J 3/0208 using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction
• CPC Class Codes: G01J 3/0216 using light concentrators or collectors or condensers
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/0227 using notch filters
• CPC Class Codes: G01J 3/0229 using masks, aperture plates, spatial light modulators or spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 3/0251 Colorimeters making use of an integrating sphere
• CPC Class Codes: G01J 3/0259 Monolithic
• CPC Class Codes: G01J 3/0264 Electrical interface; User interface
• CPC Class Codes: G01J 3/0278 Control or determination of height or angle information for sensors or receivers
• CPC Class Codes: G01J 3/0283 : using a charging unit
• CPC Class Codes: G01J 3/0291 : Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements
• CPC Class Codes: G01J 3/10 : Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01J 3/508 : measuring the colour of teeth
• CPC Class Codes: G01J 3/51 : using colour filters
• CPC Class Codes: G01J 3/513 : having fixed filter-detector pairs
• CPC Class Codes: G01N 21/474 : Details of optical heads therefor, e.g. using optical fibres
• CPC Class Codes: G01N 21/57 : Measuring gloss
• CPC Class Codes: G07D 7/1205 : Testing spectral properties
• CPC Class Codes: G07D 7/17 : Apparatus characterised by positioning means or by means responsive to positioning

Abstract

A method for determining spectral characteristics of an object is disclosed. A probe is positioned in proximity relative to the object. The probe provides light from at least first and second light sources positioned first and second distances from a central light receiver. The first light source and the central light receiver define a first critical height from the surface below which no specularly reflected light from the first light source is received by the central light receiver, and the second light source and the central light receiver define a second critical height from the surface below which no specularly reflected light from the second light source is received by the central light receiver. The first critical height is different from the second critical height.

Claims

1. A method for determining spectral characteristics of an object comprising the steps of:

positioning a probe and/or the object such that the probe is in proximity relative to the object, wherein the probe provides light to a surface of the object and receives light from the object, wherein light is provided from the probe by at least first and second light sources and light is received by at least a central light receiver, wherein the first light source is positioned a first distance from the central light receiver and the second light source is positioned a second distance from the central light receiver, and wherein the first light source and the central light receiver define a first critical height from the surface below which no specularly reflected light from the first light source is received by the central light receiver and the second light source and the central light receiver define a second critical height from the surface below which no specularly reflected light from the second light source is received by the central light receiver, wherein the first critical height is different from the second critical height;

determining the intensity of light received by the central light receiver in a plurality of spectral bands with a first measurement when the first light source is on and with a second measurement when the second light source is on;

determining the spectral characteristics of the object based on the first and second measurements.

2. The method of claim 1, wherein the first light source comprises a first ring light source.

3. The method of claim 1, wherein the first light source comprises a first plurality of discrete light sources positioned the first distance from the central light receiver.

4. The method of claim 3, wherein the first light source comprises a first ring light source.

5. The method of claim 1, wherein the first light source comprises a first ring light source and the second light source comprises a second ring light source.

6. The method of claim 1, wherein the first light source comprises a first plurality of discrete light sources positioned the first distance from the central light receiver and the second light source comprises a second plurality of discrete light sources positioned the second distance from the central light receiver.

7. The method of claim 6, wherein the first light source comprises a first ring light source and the second light source comprises a second ring light source.

8. The method of claim 1, wherein the object comprises a translucent object.

9. The method of claim 1, wherein the object comprises an opalescent object.

10. The method of claim 1, wherein the object comprises a translucent and opalescent object.

11. The method of claim 1, further comprising the step of applying monochromatic light via one or more third light sources.

12. The method of claim 11, wherein one or more measurements taken based on the application of the monochromatic light of the one or more third light sources is used to determine a physical position of the probe with respect to the object.

13. The method of claim 12, wherein the physical position comprises a distance of the probe with respect to the object.

14. The method of claim 12, wherein the physical position comprises an angle of the probe with respect to the object.

15. The method of claim 12, wherein the physical position comprises a distance and an angle of the probe with respect to the object.

16. The method of claim 1, wherein the central light receiver is coupled to a plurality of light to frequency converter optical sensors through a respective plurality of bandpass filters.

17. The method of claim 1, wherein the probe is positioned a distance from the object that is less than each of the first and second critical heights.

18. The method of claim 17, wherein the object comprises a translucent object.

19. The method of claim 17, further comprising the step of applying monochromatic light via one or more third light sources, wherein one or more measurements taken based on the application of the monochromatic light of the one or more third light sources is used to determine a physical position of the probe with respect to the object.

20. The method of claim 17, wherein the central light receiver is coupled to a plurality of light to frequency converter optical sensors through a respective plurality of bandpass filters.