Variable Focus Liquid Lens for Confocal Endomicroscopy
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Solution Overview
Problem
Current endomicroscopy techniques face challenges in maintaining a consistent focal length due to tissue surface irregularities and motion, particularly with high numerical aperture (NA) requirements, limiting comprehensive imaging of the esophagus.
Innovation Solution
A compound variable focus objective lens combining an aspheric singlet with a variable focus liquid lens, which changes focal length through water pressure without moving parts, maintaining a high NA of 0.4-0.46 and allowing adaptive focusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high numerical aperture (NA) objective lens is used for confocal endomicroscopy, then imaging resolution and cellular visualization capability are improved, but the depth of focus becomes extremely limited making it difficult to maintain consistent focal plane due to tissue surface irregularities and motion
Solution Approach 1:
The patent implements a variable focus mechanism that dynamically adjusts the focal length of the objective lens in real-time. This allows the system to adapt to tissue surface irregularities and motion by changing the focal plane depth, resolving the contradiction between high NA (which gives shallow depth of focus) and the need for adaptable focusing in vivo.
Solution Approach 2:
The patent changes the optical parameter (focal length) of the objective lens to achieve variable depth of focus while maintaining high NA. By adjusting the focal length parameter, the system can penetrate deeper into tissue and accommodate surface variations, thus resolving the limitation imposed by fixed focal length in high NA lenses.
2Measurement precision
If conventional confocal microscopy systems are used, then cellular morphology can be visualized, but the field size is limited to approximately 500 μm×500 μm requiring mosaicing and near contact imaging that prohibit comprehensive esophageal examination in realistic procedure times
Solution Approach 1:
The variable focus capability allows the system to rapidly adjust between different imaging depths and fields without physical repositioning. This dynamic focusing enables comprehensive examination of larger areas by adjusting focal planes rather than physically moving the probe or mosaicing multiple images, thus improving productivity while maintaining cellular visualization capability.
3Adaptability or versatility
If adaptive focusing mechanism using piezo-electric transducer (PZT) is implemented, then focal location can be automatically adjusted, but the device size, stability (hysteresis), and high voltage requirements become problematic for endoscopic probe applications
Solution Approach 1:
The patent replaces the piezo-electric transducer (PZT) mechanical system with an optical solution - a variable focus liquid lens or similar optical element that achieves focal adjustment through fluid pressure or optical path changes rather than mechanical movement. This substitution eliminates the size, hysteresis, and high voltage issues associated with PZT while maintaining adaptive focusing capability.
Solution Approach 2:
The patent uses fluid pressure (pneumatic or hydraulic control) to adjust the focal length of the objective lens. By controlling the pressure of a fluid-filled chamber or liquid lens, the system achieves variable focus without mechanical moving parts, thereby reducing device complexity and improving stability for endoscopic probe applications.
4Device complexity
If variable focus liquid lens is used to enable miniaturization and eliminate moving parts, then device size and biocompatibility are improved, but maintaining high numerical aperture (NA) becomes difficult
Solution Approach 1:
The patent employs composite optical designs that combine variable focus liquid lens elements with high NA optical materials and aspheric surfaces. This composite approach allows the system to achieve both miniaturization (through integration) and maintain high NA (through optimized material composition and surface geometry), resolving the contradiction between device simplicity and optical performance.
Solution Approach 2:
The patent uses aspheric surfaces and curved optical designs in the variable focus lens system. By optimizing the curvature profiles of the lens elements, the system maintains high numerical aperture despite the compact, moving-part-free design, thus resolving the contradiction between miniaturization and NA maintenance.
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
Enables miniaturization and biocompatibility for endoscopy, providing a high NA and adjustable focal length range, enhancing imaging capabilities for microscopic visualization in the esophagus and other fields.
Implementation Method 1
A compound variable focus objective lens combining an aspheric singlet with a variable focus liquid lens, which changes focal length through water pressure without moving parts
Implementation Method 2
A compound variable focus objective lens combining an aspheric singlet with a variable focus liquid lens, which changes focal length through water pressure without moving parts, maintaining a high NA of 0.4-0.46
Data Source
AI summary
An apparatus for imaging an anatomical structure(s) can be provided. For example, a housing arrangement can have a shape of a pill and can be to be delivered to the anatomical structure(s). An imaging arrangement can be configured to generate a microscopic image of the anatomical structure(s), wherein the imaging arrangement can include a variable focus lens, and can be provided in the housing arrangement.