Endoscope Light Source Device Temperature Compensation
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Solution Overview
Problem
Conventional light source devices for scanning type endoscopes face challenges in maintaining the maximum light quantity and total light quantity of laser beams to satisfy laser safety standards, particularly due to temperature variations affecting the light emission ratios of red, green, and blue laser beams.
Innovation Solution
A light source device comprising a first and second light emitting element, a beam combiner, a temperature measuring section, and a light emission control section that adjusts control signals based on temperature-dependent parameters to ensure the maximum light quantity of irradiation light satisfies predetermined conditions, using a beam combiner to transmit and divide laser beams into irradiation and monitoring light with a predetermined division ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature control devices are added to maintain laser beam light quantity within safety standards, then light safety compliance is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements a feedback mechanism where a light quantity monitor continuously detects the light quantity of laser beams, and the system controller adjusts the light emission from the semiconductor light source based on this feedback to maintain compliance with laser safety standards. This closed-loop control ensures safety without requiring complex external temperature control devices.
Solution Approach 2:
The system performs self-regulation of light quantity through integrated monitoring and control functions. The light quantity monitor and system controller work together within the existing device architecture to automatically adjust and maintain safe light emission levels, eliminating the need for additional dedicated safety control hardware.
2Reliability
If temperature control devices are added to maintain laser beam light quantity within safety standards, then light safety compliance is improved, but energy consumption increases
Solution Approach 1:
The feedback-based light quantity monitoring and control system efficiently manages energy by only adjusting light emission when necessary to maintain safety compliance. The system controller modulates the semiconductor light source based on real-time measurements, avoiding continuous full-power operation and reducing overall energy consumption compared to passive thermal control methods.
Solution Approach 2:
The system dynamically changes the operating parameters of the semiconductor light source, specifically adjusting the light emission intensity and pulse duration, to maintain safety compliance while optimizing energy efficiency. By controlling the temporal and intensity parameters rather than maintaining constant high-power emission, the system reduces energy consumption.
3Reliability
If light quantity is reduced to satisfy laser safety standards, then safety compliance is improved, but illumination intensity decreases
Solution Approach 1:
The patent employs periodic pulsed operation of the semiconductor light source, where laser beams are emitted in controlled pulses rather than continuously. This periodic action allows the peak illumination intensity during pulses to remain high for effective imaging, while the average power remains within safety limits, thus maintaining both safety compliance and illumination quality.
Solution Approach 2:
The system changes the temporal parameters of light emission by using pulsed operation with specific duty cycles. This allows the illumination intensity during active pulses to be sufficiently high for medical imaging purposes, while the time-averaged power remains compliant with laser safety standards, effectively decoupling peak intensity requirements from average power limitations.
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 solution effectively maintains the light quantity of irradiation light within laser safety standards, even with temperature changes, without the need for additional temperature control devices, thereby reducing costs and energy consumption while ensuring consistent white balance.
Implementation Method 1
a beam combiner which the first laser beam and the second laser beam enter, the beam combiner being configured to transmit a laser beam having a spectrum component based on a synthesized spectrum of the first spectrum and the second spectrum
Implementation Method 2
emit a part of the laser beam as monitoring light having an intensity at a predetermined division ratio
Implementation Method 3
a temperature measuring section configured to measure a temperature of the beam combiner
Implementation Method 4
a first light emitting element configured to emit a first laser beam of a first spectrum responding to a first control signal; a second light emitting element configured to emit a second laser beam of a second spectrum responding to a second control signal
Data Source
AI summary
R, G, B laser beams emitted from an R_LD, a G_LD, and a B_LD, respectively, are divided, through demultiplexers, into respective monitoring laser beams and respective irradiation laser beams to be applied to a scanning type endoscope side. R, G, B drive currents for causing light emission at the R_LD, the G_LD, and the B_LD are controlled such that the light quantities of the divided monitoring laser beams become equal to monitoring light quantity values on which the division ratios in the case of temperature change are reflected. As a result of this control, the light quantities of the irradiation laser beams each fall within a range satisfying a predetermined condition.