Endoscope Illumination Control With Temperature-Corrected Light Feedback
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Solution Overview
Problem
Endoscope systems face challenges in maintaining consistent illumination brightness and chromaticity due to temperature changes in the light source and light receiving elements, affecting image quality.
Innovation Solution
An endoscope system with a light source device that includes a light source, a light receiving element, first and second temperature sensors, a received light amount correction circuit, and a drive control circuit to adjust the illumination light based on temperature corrections, ensuring consistent light emission and reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the amount of illumination light is controlled based on light receiving element output, then the desired brightness is achieved, but temperature changes cause chromaticity and luminance variations
Solution Approach 1:
The system uses a light receiving element to detect the actual amount of illumination light emitted by the light source, and feeds this information back to a drive control circuit. The circuit adjusts the light source driving current based on the detected light amount to maintain consistent luminance and chromaticity despite temperature variations. This closed-loop feedback mechanism ensures reliable color and brightness consistency.
Solution Approach 2:
The invention compensates for temperature-induced variations by dynamically adjusting the driving current parameter of the light source. When temperature changes cause shifts in light output characteristics, the control circuit modifies the electrical parameters (current) supplied to the light source to counteract these variations, thereby maintaining stable chromaticity and luminance output.
2Reliability
If temperature compensation is implemented for light source, then chromaticity stability improves, but light receiving element temperature effects are not corrected
Solution Approach 1:
The light receiving element's output is used as feedback to monitor the actual illumination light amount. This feedback signal is processed by the drive control circuit to determine necessary adjustments in light source driving parameters, creating a closed-loop system that automatically compensates for temperature effects on both the light source and detection elements.
Solution Approach 2:
The system uses its own light receiving element to detect the light source output and automatically adjusts the driving current without requiring external intervention. The temperature compensation mechanism is self-regulating, where the system monitors its own performance and corrects deviations autonomously based on detected light amount variations.
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
The system effectively controls illumination light to maintain desired brightness and chromaticity, even with temperature changes, enhancing image quality and user experience.
Implementation Method 1
a light receiving element configured to receive a part of the illumination light of the light source
Implementation Method 2
a first temperature sensor configured to detect a first temperature of the light source
Implementation Method 3
a second temperature sensor configured to detect a second temperature of the light receiving element
Implementation Method 4
a received light amount correction circuit configured to correct an amount of light received by the light receiving element based on the second temperature
Data Source
AI summary
The endoscope system includes: a laser diode for an endoscope that emits illumination light whose amount can be controlled; an image pickup device that outputs an image pickup signal of an image obtained by receiving reflected light of the illumination light; a photodiode that receives a part of the illumination light of the laser diode; a thermistor that detects a temperature of the laser diode; a thermistor that detects a temperature of the photodiode; a detection light amount temperature correction circuit that corrects an amount of light received by the photodiode based on the temperature of the photodiode; and a laser diode control circuit that controls driving of the laser diode so that an amount of the illumination light becomes a set value based on a corrected amount of received light corrected by the detection light amount temperature correction circuit and the temperature of the laser diode.