Light Source Control Device for Fluorescence Signal Enhancement
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Solution Overview
Problem
The existing medical observation systems using CMOS rolling shutter type image sensors face challenges in generating suitable images due to low signal levels in fluorescence images, primarily because the fluorescence from the observation target is minute and the sensitivity of the image sensor in the fluorescence wavelength band is low, leading to difficulties in producing images suitable for observation.
Innovation Solution
A light source control device that includes a controller to manage two light sources: a first light source emitting normal light in a first entire line exposure period and a second light source emitting excitation light in a second entire line exposure period, with the excitation light also being emitted during part of the readout period, allowing for increased luminance of the fluorescence image without significantly affecting the normal light image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If excitation light is emitted only during the entire line exposure period, then luminance unevenness in the normal light image and fluorescence image is suppressed, but the signal level in the fluorescence image remains remarkably low
Solution Approach 1:
The patent applies preliminary action by causing the second light source to emit excitation light during the readout period, which is a period when charges are being read out from the pixels. This preliminary emission of excitation light during the readout period (which occurs after the exposure period) allows additional fluorescence photons to be generated and captured, thereby increasing the signal level in the fluorescence image without affecting the luminance uniformity achieved during the exposure period
2Illumination intensity
If excitation light emission period is extended to include readout period, then brightness of fluorescence image is enhanced, but potential interference with normal light image quality may occur
Solution Approach 1:
The patent applies segmentation by dividing the light emission control into distinct time segments: the first light source emits normal light during the exposure period, while the second light source emits excitation light during both the exposure period and the subsequent readout period. This temporal segmentation allows the system to enhance fluorescence image brightness by extending excitation light emission to the readout period without significantly affecting normal light image quality, as the normal light source is not active during the readout period
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 enhances the brightness of the fluorescence image, ensuring that both normal light and fluorescence images are suitable for observation, while maintaining the quality of the normal light image.
Implementation Method 1
cause a first light source to emit light in a visible wavelength band in a first entire line exposure period
Implementation Method 2
cause a second light source to emit excitation light in a second entire line exposure period
Implementation Method 3
an image obtained by irradiating the observation target with excitation light to capture fluorescence from the observation target excited by the excitation light
Data Source
AI summary
A light source control device includes a light source controller configured to: cause a first light source to emit light in a visible wavelength band in a first entire line exposure period, which is an entire line exposure period in which all horizontal lines in an effective pixel area are simultaneously exposed; cause a second light source to emit excitation light in a second entire line exposure period, which is different from the first entire line exposure period; and cause the excitation light to be emitted in an excitation light emission period including the second entire line exposure period and a period, which is adjacent to the second entire line exposure period and is at least a part of a readout period during which charges accumulated in the plurality of pixels are read out, when controlling an operation of the second light source.