Endoscope Illumination Optical Systems for Balanced Light Distribution
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Solution Overview
Problem
Existing endoscopes face challenges in ensuring sufficient light distribution during both normal and close observations, with previous solutions either limiting close observation capabilities or increasing the diameter of the distal end, and neglecting light distribution in normal observation.
Innovation Solution
The endoscope is designed with a plurality of illumination optical systems and an observation optical system that satisfy specific conditional expressions to achieve balanced light distribution, ensuring high center brightness relative to peripheral brightness in both magnified close and normal observations, by adjusting focal lengths and optical system configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a same illumination optical system is used for both normal observation and close observation, then the device complexity is reduced, but in close observation the peripheral part of the screen becomes brighter than the center, resulting in insufficient distribution of illuminating light
Solution Approach 1:
The illumination optical system is divided into multiple independent illumination units (first and second illumination optical systems), each with its own light source and optical path. This segmentation allows each unit to be optimized for specific illumination requirements, enabling uniform light distribution across the observation field during close observation while maintaining system functionality.
Solution Approach 2:
Different regions of the observation field are provided with tailored illumination characteristics. The first illumination optical system targets the central region while the second targets the peripheral region, ensuring that each area receives appropriate light intensity and distribution characteristics for optimal observation quality.
2Illumination intensity
If the best focal position is set at a distance that provides sufficiently wide distribution of light from the illumination optical systems, then light distribution is improved, but it becomes difficult to bring the endoscope close to a subject, making it unsuitable for magnified observation
Solution Approach 1:
The illumination function is segmented into multiple optical systems positioned at different locations. The first illumination optical system is positioned to provide central illumination, while the second is positioned for peripheral illumination. This allows the endoscope to be placed close to the subject while maintaining uniform light distribution across the entire observation field through coordinated illumination from multiple sources.
3Illumination intensity
If a large distance is provided between the observation optical system and the illumination optical systems, then light distribution is ensured, but the diameter of the distal end of the endoscope increases
Solution Approach 1:
Instead of increasing the radial distance between illumination and observation optical systems (which would increase distal end diameter), the solution utilizes the longitudinal dimension by positioning multiple illumination optical systems at different axial locations. This allows sufficient illumination distance to be achieved while maintaining a compact distal end profile.
Solution Approach 2:
The illumination function is distributed across multiple compact optical systems arranged in a space-efficient configuration. By segmenting the illumination provision into multiple units positioned at different locations, the system achieves adequate illumination distance without requiring a large overall distal end diameter.
4Adaptability or versatility
If existing endoscope designs are used, then normal observation is possible, but light distribution in normal observation is not considered, resulting in insufficient brightness distribution
Solution Approach 1:
The multiple illumination optical systems are designed to serve dual purposes: they provide optimized illumination for close magnified observation while simultaneously ensuring adequate light distribution for normal observation. This multi-functional design allows the system to adapt to different observation modes without sacrificing brightness distribution quality in either mode.
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 ensures favorable observation in both normal and close observation modes by maintaining proper light distribution, preventing excessive brightness that hinders depth observation and ensuring sufficient peripheral brightness.
Implementation Method 1
a plurality of illumination optical systems 2 each including a plurality of lenses and illuminating the subject with illuminating light
Implementation Method 2
an observation optical system including a plurality of lenses and having a function that allows a magnified observation close to a subject
Data Source
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AI summary
In both of normal observation and close observation, sufficient light distribution is ensured and favorable observation is thereby performed. Provided is an endoscope including an observation optical system 1 that allows a magnified observation close to a subject, and a plurality of illumination optical systems 2 that illuminate the subject with illuminating light, wherein in a close observation in which a distance between a distal end face of an insertion portion and the subject is 1.5 mm to 2.5 mm, where ITM is a maximum brightness within an observation view field angle and ITC is a center brightness, and in a normal observation in which the distance between the distal end face of the insertion portion and the subject is 50 mm, where ICW is a center brightness and IWS is a brightness at a position of 80% of a maximum view angle, the following conditional expressions are satisfied: 0.3<ITC/ITM<0.45 0.15<IWS/IWC<0.25 and 0.3<fLfT/ϕLIH<0.6 where fL is a focal length of each of the entire illumination optical systems, fT is a focal length of the entire observation optical system in a maximum magnification, ϕL is an outer diameter of a lens that is farthest on an object side of each illumination optical system, and IH is a maximum image height of the observation optical system.