Reflectance sensor for integral illuminant-weighted CIE color matching filters

• US 20060215162A1
• Filed: 03/23/2006
• Published: 09/28/2006
• Est. Priority Date: 03/23/2005
• Status: Active Grant

• Current Assignee: Data Holding AG
• Original Assignee: Data Holding AG
• Inventors: Vrhel, Michael, Slocum, David, Shannon, Colman
• Granted Patent: US 7,474,402 B2
• Time in Patent Office: Days
• US Class Current: 356/419
• CPC Class Codes: G01J 2003/467 Colour computing
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0251 Colorimeters making use of an integrating sphere
• CPC Class Codes: G01J 3/0259 Monolithic
• CPC Class Codes: G01J 3/027 Control of working procedures of a spectrometer; Failure detection; Bandwidth calculation
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• 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: G01J 3/513 having fixed filter-detector pairs

Abstract

A tristimulus colorimeter for measuring reflective or transmissive materials is provided. The colorimeter measures a sample under a calibrated light source, receives inputs to detectors, and determines CIE tristimulus values of the same sample as they would occur under a reference light source. The colorimeter includes a calibrated light source and a single silicon chip that includes three or more detectors. Each detector is permanently coated by a different mix of dyes or other colorants that form a wavelength-selective filter. A single silicon chip embodies all the detectors and electronics, with each detector coated over by deposited filter layers.

Claims

1. A solid-state color-measuring device, comprising:

at least one light source comprising a calorimeter illuminant for illuminating a sample;

a plurality of light detectors; and

a plurality of filters that are permanently deposited onto the solid-state color-measuring device, the filters being included in a plurality of layers such that light reflected off the sample passes through the layers and causes the light detectors to cause the solid-state color-measuring device to produce an output having a plurality of colorimeter-illuminant-weighted spectral responses each approximating a reference-illuminant-weighted CIE-like color-matching function.

2. The solid-state color-measuring device of claim 1, embedded in a color printer.

3. The solid-state color-measuring device of claim 1, wherein the solid-state color-measuring device operates in a fixed position with respect to the sample being measured.

4. The solid-state color-measuring device of claim 1, wherein the solid-state color-measuring device operates in a motion with respect to the sample being measured.

5. The solid-state color-measuring device of claim 1, wherein the light detectors are identical.

6. The solid-state color-measuring device of claim 1, wherein each filter has a thickness such that the thicknesses of the filters in combination produce the output having the spectral responses approximating the illuminant-weighted CIE-like color-matching function.

7. The solid-state color-measuring device of claim 1, wherein each filter is permanently deposited onto a single detector.

8. The solid-state color-measuring device of claim 1, wherein a set of combinations of layers is determined, each of the combinations being determined so that the output has the colorimeter-illuminant-weighted spectral responses that are linearly combined to approximate a set of reference-illuminant-weighted CIE-like color-matching functions;

and further wherein one of the combinations is selected from the set having a best solution and meeting predetermined performance criteria, the selected combination being permanently deposited onto the solid-state color-measuring device.

9. The solid-state color-measuring device of claim 1, wherein the plurality of filters includes an infrared light filter.

10. The solid-state color-measuring device of claim 1, wherein the plurality of filters includes an ultraviolet light filter.

11. A calorimeter, comprising:

at least one light source comprising a colorimeter illuminant for illuminating a sample;

a semiconductor substrate having at least three photodetectors;

at least three filters permanently deposited on the at least three photodetectors, each filter is included in a set of layers having at least a single layer and at least one double layer; and

a plurality of channels including the photodetectors and filters so that particular linear combinations of a plurality of colorimeter-illuminant-weighted spectral responses of the channels each approximate a reference-illuminant-weighted CIE-like color-matching function.

12. The calorimeter of claim 11, embedded in a color printer.

13. The colorimeter of claim 11, wherein the colorimeter operates in a fixed position with respect to the sample being measured.

14. The colorimeter of claim 11, wherein the colorimeter operates in motion with respect to the sample being measured.

15. The colorimeter of claim 11, wherein the filters are integral with the photodetectors.

16. The colorimeter of claim 11, wherein the semiconductor substrate has four photodetectors.

17. The colorimeter of claim 16, wherein the layers include all single layers.

18. The colorimeter of claim 11, wherein the layers include one double layer and three single layers.

19. The colorimeter of claim 18, wherein the double layer is cyan and magenta and the three single layers are red, green, and yellow.

20. The colorimeter of claim 16, wherein the layers include two double layers and two single layers.

21. The colorimeter of claim 11, wherein the layers include three double layers and one single layer.

22. The colorimeter of claim 11, wherein a thickness of each filter is between about 0.50 microns and 2.00 microns.

23. The colorimeter of claim 11, wherein the semiconductor substrate has 64 photodetectors.

24. The calorimeter of claim 11, wherein the filters are absorptive.

25. A system including the calorimeter of claim 11, wherein the system is a printer calibration system.

26. The calorimeter of claim 11, wherein the at least one filter includes an infrared light filter.

27. The calorimeter of claim 11, wherein the at least one filter includes an ultraviolet light filter.