Hemispherical Planoconvex Lens for Compact Endoscope Optics
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Solution Overview
Problem
Existing ultrasonic endoscopes face challenges in creating high-quality ultrasonic images due to the limited space available for the transducer, which requires a compact objective optical system.
Innovation Solution
The objective optical system comprises a flat plate, an aperture stop, and a substantially hemispherical planoconvex lens, where the flat plate and planoconvex lens are cemented together with the aperture stop in between, and the system satisfies specific conditional expressions to optimize image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the transducer is disposed at the distal end of the insert part to facilitate contact with the observed object, then the ease of operation is improved, but the available space for the transducer is limited because the objective optical system must be positioned closer to the operation part
Solution Approach 1:
The patent employs a hemispherical lens with a specific curvature radius relationship (R1 = -R2) to achieve compact optical path folding. This spherical geometry allows the objective optical system to maintain a small form factor while providing sufficient working distance for the transducer at the distal end, resolving the space constraint imposed by the distal transducer placement.
Solution Approach 2:
The objective optical system is designed with a nested structure where the hemispherical lens encompasses the aperture stop and cemented flat plate within its curved geometry. This nesting arrangement minimizes the overall volume of the optical system, creating adequate space for the transducer while maintaining the required optical functionality.
2Volume of moving object
If the objective optical system is made small to provide large space for the transducer, then the volume of the optical system is reduced, but the image quality may deteriorate due to constraints on optical component design
Solution Approach 1:
The patent optimizes specific optical parameters including the curvature radius relationship (R1 = -R2), the cementing of the flat plate to the hemispherical lens, and the aperture stop positioning to achieve diffraction-limited performance. These parameter optimizations enable the compact optical system to maintain high image quality despite its small size.
Solution Approach 2:
The objective optical system uses a composite structure combining a flat plate, aperture stop, and hemispherical lens cemented together. This composite design allows each component to contribute optimally to the overall performance, achieving high-resolution imaging in a compact form factor suitable for endoscopic applications.
3Device complexity
If a compact objective optical system is used to accommodate the transducer at the distal end, then the device complexity is reduced, but the difficulty of detecting and measuring increases due to limited space for optical components
Solution Approach 1:
The objective optical system is segmented into distinct functional components: a flat plate, an aperture stop, and a hemispherical lens. This segmentation allows each component to be optimized independently for its specific function while maintaining overall compactness, reducing assembly complexity while preserving imaging quality.
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 the formation of optical images that can be observed without difficulties, enabling the ultrasonic endoscope to produce high-quality ultrasonic images while maintaining a compact size.
Implementation Method 1
a substantially hemispherical planoconvex lens
Implementation Method 2
the planoconvex lens having an object side surface Ro and an image side surface Ri, the image side surface Ri being a spherical surface
Implementation Method 3
the flat plate and the planoconvex lens are cemented together
Data Source
AI summary
There is provided an objective optical system that is easy to produce, capable of forming optical images that can be observed without difficulties while small in size. The objective optical system includes, in order from the object side, a flat plate OP1, an aperture stop S, and a substantially hemispherical planoconvex lens L1 having an outer diameter substantially equal to the outer diameter of the flat plate. The flat plate and the planoconvex lens L1 are cemented together with the aperture stop between. The objective optical system satisfies the following conditional expressions (1), (2), and (3):0.3<IH/Dp<0.45 (1)1.7<1+Dp×ωr/(2×IH)<2.1 (2)0.9<NL/(1+Dp×ωr/(2×IH))<1.1 (3).