UV Fluorescence Detection Device White Balance Correction
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Solution Overview
Problem
Conventional UV ray fluorescence color detection methods for securities or banknotes face challenges in accurately detecting the fluorescence color with sufficient contrast due to issues with white balance correction and temperature-output characteristics of LEDs, particularly when using color filters with narrow wavelength ranges.
Innovation Solution
Employing a white LED light source with a phosphor that emits a broad visible light range, allowing for a white reference output to correct sensitivity across color filters, thereby enabling precise detection of fluorescence colors during UV irradiation by using the output from a white reference object to balance the signals from light receiving elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a white LED light source with phosphor is used to emit broad visible light range, then the reading precision of fluorescence color is improved, but the device complexity increases due to additional white balance correction mechanisms
Solution Approach 1:
The patent applies preliminary action by performing white balance correction using a white reference object before actual fluorescence detection. The correction coefficients are calculated in advance by comparing the broad spectrum light source output with a known white reference, allowing the system to compensate for color filter sensitivity variations and LED spectral characteristics before measuring the fluorescence signal.
Solution Approach 2:
The patent uses a white reference object as an intermediary to establish the relationship between the broad spectrum LED light source and the color filter responses. This reference object mediates the calibration process by providing a known spectral reflectance that allows calculation of correction coefficients, which then serve as a mapping between the LED's broad spectrum output and the expected white balance across all color filters.
2Measurement precision
If color filters with narrow wavelength ranges are used to detect specific fluorescence colors, then the measurement precision is improved, but the detection accuracy deteriorates due to sensitivity imbalance across different color filters
Solution Approach 1:
The patent implements feedback by using the white reference object to measure the actual sensitivity of each color filter to the broad spectrum LED light source. These measured values are fed back to calculate correction coefficients that compensate for sensitivity imbalances. During fluorescence detection, the same correction coefficients are applied to normalize the signals from different color filters, ensuring accurate color discrimination despite the narrow bandwidth of individual filters.
3Adaptability or versatility
If multiple LEDs with different wavelengths are used to illuminate the medium, then the discrimination capability is improved, but the loss of time increases due to sequential switching of LEDs
Solution Approach 1:
The patent merges multiple wavelength sources into a single broad spectrum white LED light source with phosphor conversion. This consolidation eliminates the need for sequential switching of multiple LEDs while maintaining the ability to excite various fluorescence emissions. The broad spectrum output of the white LED simultaneously covers multiple wavelength ranges, allowing parallel detection of different fluorescence colors without time loss from switching operations.
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 allows for high-quality image acquisition with desired color balance, improving the reading precision of fluorescence colors emitted during UV light irradiation, enabling accurate discrimination of securities or banknotes.
Implementation Method 1
a white LED light source which emits white light by emitting fluorescence from a phosphor
Implementation Method 2
detecting a fluorescence color emitted from a phosphor contained in the securities or banknote during UV ray irradiation
Data Source
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AI summary
There are provided a UV ray fluorescence color detection device capable of simply and accurately detecting a visible fluorescence color emitted from a medium during UV light irradiation, and a method for detecting a UV ray fluorescence color. A UV ray is emitted from a UV light source (first light source portion 4) to the medium. A white light is emitted from a white LED light source (light source in a second light source portion 3) by emitting a fluorescence from a phosphor. A light enters into a plurality of light receiving elements provided in a light receiving portion through at least one visible light color filter. An output signal is obtained from the light receiving elements when the UV light is emitted from the UV light source to the medium, and a fluorescence is emitted from the medium to the plurality of light receiving elements through the visible light color filter, and the output signal is corrected based on an output signal obtained from the light receiving elements when the white light is emitted from the white LED light source to a white reference object 200 and a light is emitted from the white reference object 200 to the plurality of light receiving elements through the visible light color filter.