Spectral Spatial Calibration Illuminator for Spectrophotometers
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Solution Overview
Problem
Conventional spectrophotometers fail to provide detailed spatial and spectral information, making them impractical for calibrating systems that require both spatial and spectral data, as they typically offer average values over large areas and lack detailed spectral information across wavelengths.
Innovation Solution
A system combining a full-width illumination source with LEDs emitting discrete spectral peaks and a full-width photodetector array with filters, such as red, green, and blue channels, allows for rapid spectral and spatial calibration by capturing optical responses from test patches illuminated with different wavelengths, enabling highly resolved spectral and spatial data collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional spectrophotometers are used to measure spectral characteristics, then spectral information can be obtained, but detailed spatial information is lost and only average values over large areas are provided
Solution Approach 1:
The detection system is segmented into multiple spatial elements (pixels) arranged in an array, where each element independently detects spectral information from a corresponding spatial location. This segmentation allows simultaneous acquisition of both spectral and spatial data, resolving the contradiction between spectral precision and spatial information loss.
Solution Approach 2:
The invention transitions from one-dimensional spectral measurement to two-dimensional measurement by adding the spatial dimension through a photodetector array. Each detector element in the array corresponds to a specific spatial location while maintaining spectral detection capability, thus adding spatial information without sacrificing spectral precision.
2Loss of information
If multiple measurements are taken at different fields of view to obtain reflectance values for discrete regions, then spatial information can be improved, but measurement time increases and productivity decreases
Solution Approach 1:
The photodetector array is divided into multiple independently operating detector elements, each capturing spectral information from a different spatial location simultaneously. This parallel segmentation enables acquisition of spatially resolved spectral data in a single measurement, eliminating the need for sequential measurements and thereby maintaining high productivity.
Solution Approach 2:
The system performs continuous spectral measurement across all spatial locations simultaneously through the detector array, rather than sequentially scanning different fields of view. This continuous parallel measurement maintains measurement speed while providing complete spatial information.
3Loss of information
If CMOS or CCD optical detection arrays are used to obtain detailed spatial information, then spatial resolution is improved, but spectral information is limited and integration across all wavelengths occurs
Solution Approach 1:
The detector array is segmented such that each spatial element functions as an independent spectral detector. By combining the spatial segmentation of the array with spectral detection capability at each element, the system simultaneously achieves detailed spatial information and precise spectral measurement, resolving the contradiction between spatial and spectral precision.
4Measurement precision
If an array with separate red, green and blue detection is used, then three pieces of spectral information are obtained, but the number of detection elements triples
Solution Approach 1:
Each detector element in the array is designed to be multi-functional, capable of detecting spectral information across multiple wavelengths simultaneously. This universality allows a single detector element to perform the function of multiple specialized detectors, reducing the total number of elements needed while maintaining spectral information quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables precise spectral and spatial calibration, achieving color accuracy within 5 units (Delta E) and providing detailed information for devices like printers, improving print quality evaluation and colorimetric data collection.
Implementation Method 1
an illumination system comprising a full width illumination source such as a light pipe coupled to several light emitting diodes (LEDs), of different illumination spectra that can be rapidly switched
Implementation Method 2
reflecting a portion of the white light illumination output from the test patch to form a white light reflected illumination output
Implementation Method 3
a full width detection array which provides a full width spectral response
Data Source
AI summary
A method of spatially and spectrally calibrating a spectrophotometer including: a) emitting a white light illumination output from a full width illumination source; b) illuminating a test patch with the white light illumination output; c) reflecting a portion of the white light illumination output from the test patch to form a white light reflected illumination output; d) receiving the white light reflected illumination output at first, second and third rows of photosensitive elements to form a first calibration data set; e) emitting a cyan light illumination output from the full width illumination source; f) illuminating the test patch with the cyan light illumination output; g) reflecting a portion of the cyan light illumination output from the test patch to form a cyan light reflected illumination output; and, h) receiving the cyan light reflected illumination output at the second and third rows of photosensitive elements to form a second calibration data set.