Reflectance sensor for integral illuminant-weighted CIE color matching filters

• US 7,474,402 B2
• Filed: 03/23/2006
• Issued: 01/06/2009
• Est. Priority Date: 03/23/2005
• Status: Expired due to Fees

• Current Assignee: Data Holding AG
• Original Assignee: Datacolor Holding AG
• Inventors: Vhrel, Michael, Slocum, David, Shannon, Colman
• Primary Examiner(s): Geisel; Kara E.
• Assistant Examiner(s): Giglio; Bryan
• Application Number:
  US11/387,376
• Publication Number:
  US 20060215162A1
• Time in Patent Office: 1,020 Days
• Field of Search: 356/402, 356/419, 356/405, 356/406
• US Class Current: 356/405
• 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 colorimeter 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 plurality 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,

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

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

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

4. The solid-state color-measuring device of claim 1, wherein the solid-state color-measuring device is embedded in a color printer.

5. 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.

6. 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.

7. The solid-state color-measuring device of claim 1, wherein the plurality of light detectors is identical.

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

9. The solid-state color-measuring device of claim 1, wherein each of the plurality of filters is permanently deposited onto a single one of the plurality of light detectors.

10. A colorimeter, comprising:

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

a semiconductor substrate having four photodetectors;

four filters permanently deposited on the four photodetectors, wherein each of the four filters is included in a set of layers, wherein one of the four filters comprises a double layer and three of the four filters comprise single layers, and wherein the double layer is cyan and magenta and the single layers are, respectively, red, green, and yellow; and

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

11. The colorimeter of claim 10, wherein a thickness of each of the four filters is between about 0.50 microns and 2.00 microns.

12. The colorimeter of claim 10, wherein the semiconductor substrate has 64 photodetectors.

13. The colorimeter of claim 10, wherein the four filters are absorptive.

14. A system including the colorimeter of claim 10, wherein the system is a printer calibration system.

15. The colorimeter of claim 10, wherein the four filters include an infrared light filter.

16. The colorimeter of claim 10, wherein four filters include an ultraviolet light filter.

17. The colorimeter of claim 10, wherein the colorimeter is embedded in a color printer.

18. The colorimeter of claim 10, wherein the colorimeter operates in a fixed position with respect to the sample being measured.

19. The colorimeter of claim 10, wherein the colorimeter operates in motion with respect to the sample being measured.

20. The colorimeter of claim 10, wherein the four filters are integral with the four photodetectors.