Light source wavelength correction
First Claim
Patent Images
1. A method of correcting one or more reflectance values when a center wavelength of one or more light sources used to generate corresponding light signals is different from a specified center wavelength for the one or more light sources, the method comprising the steps of:
- A. defining, for each of the one or more light sources, a reference spectral distribution {L*} that is characteristic of the one or more light sources and composed of reference light intensity values over a set of reference wavelengths;
B. defining, for each of the one or more light sources, a spectral distribution {L} comprising actual light intensity values over the set of wavelengths;
C. determining the actual reflectance R of a set of reflected signals;
D. defining a set of detector sensitivity data {D} corresponding to the set of detectors receiving the set of reflected signals;
E. determining high resolution reflectance values {r};
F. determining a correction factor as a function of {L}, {L*}, {r} and {D}; and
G. applying the correction factor to R to determine R*.
4 Assignments
0 Petitions
Accused Products
Abstract
A wavelength correction function provides corrected reflectance values from actual reflectance values taken in a reflectance-base instrument. The correction is provided as a function of measured reflectance values and a predefined set of high resolution reflectance values established for the reflectance-based instrument implementing the wavelength correction function.
-
Citations
27 Claims
-
1. A method of correcting one or more reflectance values when a center wavelength of one or more light sources used to generate corresponding light signals is different from a specified center wavelength for the one or more light sources, the method comprising the steps of:
-
A. defining, for each of the one or more light sources, a reference spectral distribution {L*} that is characteristic of the one or more light sources and composed of reference light intensity values over a set of reference wavelengths; B. defining, for each of the one or more light sources, a spectral distribution {L} comprising actual light intensity values over the set of wavelengths; C. determining the actual reflectance R of a set of reflected signals; D. defining a set of detector sensitivity data {D} corresponding to the set of detectors receiving the set of reflected signals; E. determining high resolution reflectance values {r}; F. determining a correction factor as a function of {L}, {L*}, {r} and {D}; and G. applying the correction factor to R to determine R*. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A center wavelength correction system configured to correct one or more reflectance values when a center wavelength of one or more light sources used to generate corresponding light signals is different from a specified center wavelength for the one or more light sources, the system comprising:
-
A. a spectral distribution module configured to determine, for each of the one or more light sources, a spectral distribution {L} comprising actual light intensity values over the set of wavelengths; B. a reflectance module configure to determine actual reflectance R from a set of reflected signals; C. at least one storage device comprising; 1) for each of the one or more light sources, a reference spectral distribution {L* } that is characteristic of the one or more light sources and composed of reference light intensity values over a set of reference wavelengths; 2) high resolution reflectance values {r}; and 3) detector sensitivity data {D} corresponding to the set of detectors receiving the set of reflected signals; D. a correction function module configured to determine a correction factor at a given wavelength as a function of {L}, {L*}, {r} and {D} and to apply the correction factor to R to determine R*. - View Dependent Claims (9, 10, 11, 12, 13, 14)
-
-
15. A wavelength correction means for correcting one or more reflectance values when a center wavelength of one or more light sources used to generate corresponding light signals is different from a specified center wavelength for the one or more light sources, the system comprising:
-
A. a spectral distribution means for determining, for each of the one or more light sources, a spectral distribution {L} comprising actual light intensity values over the set of wavelengths; B. a reflectance means for determining actual reflectance R from a set of reflected signals; C. at least one storage means far storing; 1) for each of the one or more light sources, a reference spectral distribution {L} that is characteristic of the one or more light sources and composed of reference light intensity values over a set of reference wavelengths; 2) high resolution reflectance values {r}; and 3) detector sensitivity data {D} corresponding to the set of detectors receiving the set of reflected signals; D. a correction function means for determining a correction factor at a given wavelength as a function of {L}, {L*}, {r} and {D} and to apply the correction factor to R to determine R*. - View Dependent Claims (16, 17, 18, 19, 20, 21)
-
-
22. A reflectometer comprising:
-
A. a set of light sources; B. a set of detectors; C. a reflectance assembly configured to direct light signals from the set of light sources onto a test product and to direct light signals reflected from the test product onto the set of detectors; D. at least one storage device configured to store a reference spectral distribution {L*}, a set of high resolution reflectance values {r}, a set of detector sensitivity data {D} corresponding to the set of detectors, a measured spectral distribution {L} corresponding tote set of light sources, and a set of measured reflectance values R; and E. a correction function module for determining a correction factor at a given wavelength as a function of {L}, {L*}, {r} and {D} and to apply the correction factor to R to determine R*. - View Dependent Claims (23, 24)
-
-
25. A wavelength correction module, in a reflectance-based system comprising a set of light sources, a set of detectors, and a reflectance assembly configured to direct light signals from the set of light sources onto a test product and to direct light signals reflected from the test product onto the set of detectors, the wavelength correction module comprising:
-
A. at least one storage device configured to store a reference spectral distribution {L*}, a set of high resolution reflectance values {r}, a set of detector sensitivity data {D} corresponding to the set of detectors, a measured spectral distribution {L} corresponding to the set of light sources, and a set of measured reflectance values R; and B. a correction function module for determining a correction factor at a given wavelengths a function of {L}, {L*}, {r} and {D} and to apply the correction factor to R to determine R*. - View Dependent Claims (26, 27)
-
Specification