Implantable Microscope with Tunable Lens for Variable Focus
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Solution Overview
Problem
Conventional microscopes are too large to be implanted within biological specimens without causing damage, and GRIN-optic cannula-based microscopes have a fixed working distance, limiting their ability to observe fluorescent emissions or structures at multiple object planes.
Innovation Solution
A compact microscope system with an electrically-tunable lens that adjusts the optical path length, allowing for adjustable focus and imaging depth, enabling optogenetic stimulation and fluorescence imaging at multiple object planes, and incorporating a dual-wavelength system with multiple image sensors and filters for precise imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional microscopes with large objectives are used, then imaging quality is improved, but the size increases making them unsuitable for in vivo implantation
Solution Approach 1:
The patent integrates the illumination source, optical components, and imaging sensor within a compact cannula structure. The GRIN lens is positioned at the tip of the cannula, with illumination fibers and detection optics nested within the same cylindrical volume, enabling the entire microscope system to fit within a small implantable probe while maintaining functional performance
Solution Approach 2:
The patent uses a GRIN (Gradient Index) lens as an intermediary optical element to relay images from deep within the sample to the objective lens. This GRIN lens acts as a waveguide that transports optical information over the working distance without requiring the objective lens to be physically close to the sample, enabling compact design while maintaining imaging quality
2Volume of moving object
If GRIN-optic cannula-based microscopes are used, then size is reduced for in vivo implantation, but the working distance becomes fixed limiting observation at multiple object planes
Solution Approach 1:
The patent introduces a movable stage or adjustable mounting mechanism that allows the objective lens to be positioned at different distances from the GRIN lens tip. This dynamic adjustment capability enables the fixed-focus GRIN-optic cannula to observe structures at multiple object planes by mechanically varying the working distance, thereby achieving adaptability while maintaining the compact implantable design
Solution Approach 2:
The patent varies the working distance parameter by adjusting the position of the objective lens relative to the GRIN lens. By changing this geometric parameter, the system can focus on different depths within the sample, transforming a fixed-focus system into one that can observe multiple object planes without changing the physical structure of the implantable probe
3Object-affected harmful factors
If large objectives are used to avoid sample damage, then invasiveness is reduced, but the ability to access deep layers within the sample is limited
Solution Approach 1:
The GRIN lens serves as an intermediary that extends the effective working distance optically. It guides light from deep within the sample back to the objective lens, allowing the objective to remain at a safe distance from the sample (reducing damage) while still capturing images from deep layers through the GRIN lens's light-guiding capability
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 provides increased focus repeatability, reduced size, and improved invasiveness, enabling high-resolution imaging at a micron scale with adjustable focus, suitable for monitoring cell activity and optogenetic applications.
Implementation Method 1
an electrically-tunable lens positioned between the objective lens and the image sensor for adjusting an optical path length between the at least one optical interface and the image sensor. By adjusting a voltage supplied to the electrically-tunable lens, a focus of the image or a depth of the image within the sample is adjusted
Implementation Method 2
The illumination provided from the illumination source to the sample is focused at or near to the back focal plane of the objective lens, so that the objective lens collimates or quasi-collimates the illumination provided to the sample, while the objective lens focuses light returning from the sample on the image sensor(s)
Implementation Method 3
a beamsplitter positioned between the objective lens and the image sensor for separating the light returning from the sample from the illumination
Implementation Method 4
When making microscopic observations of in vivo biological specimens... capable of observing images at multiple object planes/focal lengths... for in vivo or in vitro fluorescence imaging
Data Source
AI summary
A miniaturized microscope having a tunable focal length provides for fluorescence measurements at an adjustable focus, providing for autofocus and/or depth adjustment of an image measurement without altering or adjusting a probe implanted in a sample and while providing collimated illumination of an area within the sample. The microscope includes an objective lens having a fixed position with respect to a second connector for receiving light returning from the sample and focusing it on an image sensor within the microscope that generates an image output, a beamsplitter for separating light returning from the sample, and an electrically-tunable lens positioned between the objective lens and the image sensor for adjusting an optical path length from the optical interface to the image sensor. The illumination is focused at or near a back focal plane of the objective lens to the sample, providing collimated or quasi-collimated illumination on or within the sample.