Radiation Image Reader Optical Filter Design
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Solution Overview
Problem
Radiation image reading devices face a challenge in reducing device size while maintaining detection accuracy, as decreasing the distance between the light detection unit and the recording medium can lead to a decrease in radiation image detection accuracy due to signal light divergence.
Innovation Solution
Incorporating an optical filter with specific transmittance characteristics between the light detection unit and the recording medium, which attenuates excitation light and signal light at angles greater than a predetermined angle, and allows signal light at smaller angles to pass through, ensuring consistent detection across the scan line, and using a converging optical element to focus light onto photodetector elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the light detection unit is disposed closer to the recording medium to reduce device size, then device size decreases, but radiation image detection accuracy decreases due to signal light divergence
Solution Approach 1:
An optical filter is introduced as an intermediary component between the recording medium and the light detection unit. This optical filter selectively transmits signal light while blocking excitation light, enabling the light detection unit to be positioned closer to the recording medium without compromising detection accuracy. The optical filter mediates the interaction between the diverging signal light and the detector, maintaining measurement precision despite reduced distance.
Solution Approach 2:
The patent changes the optical parameters of the system by introducing an optical filter with specific transmittance characteristics. The filter's angular-dependent transmittance allows signal light within a certain angle range to pass through while blocking excitation light. This parameter change enables the light detection unit to be positioned closer to the recording medium while maintaining detection accuracy by controlling which light reaches the detector.
2Volume of moving object
If the light detection unit is positioned closer to the recording medium, then device size decreases, but excitation light reflected from the recording medium is more likely to be incident on the light detection unit
Solution Approach 1:
The optical filter serves as a mediator that selectively blocks excitation light reflected from the recording medium while allowing signal light to pass through. By positioning the optical filter between the recording medium and the light detection unit, the harmful excitation light is filtered out before reaching the detector, preventing interference even when the device size is reduced and the detector is closer to the medium.
Solution Approach 2:
The optical filter's transmittance parameters are specifically designed to block excitation light wavelengths while transmitting signal light wavelengths. This parameter change in the optical system allows the light detection unit to be positioned closer to the recording medium without suffering from excitation light interference, as the filter selectively removes the harmful excitation light based on its optical parameters.
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 configuration allows for a reduction in device size without compromising radiation image detection accuracy by ensuring uniform signal light detection across the scan line, even when the light detection unit is positioned closer to the recording medium.
Implementation Method 1
an optical filter which is disposed between the light detection unit and the surface of the recording medium, in which each of a transmittance when the excitation light reflected from the surface of the recording medium is transmitted through the optical filter and a transmittance when the signal light emitted from the surface of the recording medium at an angle larger than a predetermined angle is transmitted through the optical filter is smaller than a transmittance when the signal light emitted from the surface of the recording medium at an angle smaller than the predetermined angle is transmitted through the optical filter
Data Source
AI summary
A radiation image reading device includes: a light scanning unit; a light detection unit. Each of a transmittance when the excitation light reflected from the surface of the recording medium is transmitted through the optical filter and a transmittance when the signal light emitted from the surface of the recording medium at an angle larger than a predetermined angle with respect to a direction perpendicular to the scan line within the detection surface is transmitted through the optical filter is smaller than a transmittance when the signal light emitted from the surface of the recording medium at an angle smaller than the predetermined angle with respect to a direction perpendicular to the scan line within the detection surface is transmitted through the optical filter.