Handheld Confocal Microscope Telescope Lens Configuration
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Solution Overview
Problem
Confocal microscopes face challenges in achieving compact configurations for handheld applications while maintaining image resolution and numerical aperture over the full scan angle, and resonant scanners tend to drift due to inefficiencies in power management, leading to heating issues and reduced performance.
Innovation Solution
The use of a telescope lens system with two lenses, where one lens images between scanning mirrors and the other provides sufficient magnification to overfill the objective's entrance pupil, combined with digital control of resonant scanners to maintain frequency and phase, reducing power dissipation and heating, and employing a dual-variable control loop for dynamic image zooming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single telescope lens is used to relay the scanning beam, then the device complexity is reduced, but the numerical aperture at the objective lens entrance pupil deteriorates over the full scan angle
Solution Approach 1:
The patent divides the telescope function into two separate lenses: a first telescope lens for beam relay and a second telescope lens for numerical aperture maintenance. This segmentation allows each lens to be optimized for its specific function, resolving the contradiction between device complexity and numerical aperture maintenance.
Solution Approach 2:
The patent introduces an intermediary optical element (the second telescope lens) between the first telescope lens and the objective lens. This intermediary component specifically addresses the numerical aperture deterioration by providing additional magnification to overfill the objective's entrance pupil, while the first telescope lens handles the beam relay function.
2Volume of moving object
If resonant scanners are used for compact configuration, then the device size is reduced, but the stability of the scanner deteriorates due to frequency drift and heating
Solution Approach 1:
The patent implements feedback control mechanisms to monitor and adjust the resonant scanner's operating frequency and temperature. This feedback system compensates for frequency drift and heating effects, maintaining scanner stability while preserving the compact configuration benefits.
Solution Approach 2:
The patent employs periodic cooling cycles and frequency adjustment routines to counteract thermal drift and resonance frequency changes. By implementing periodic maintenance actions, the system maintains stable scanner performance throughout operation while keeping the compact design.
3Ease of operation
If the beam is relayed by a telescope lens focused on one scanner, then the scanning beam is properly directed, but the illumination reaches the desired location with reduced intensity
Solution Approach 1:
The patent segments the beam relay function between two telescope lenses: the first lens handles beam direction and positioning, while the second lens provides additional magnification to ensure proper illumination intensity at the objective lens. This division of labor resolves the contradiction between beam control and illumination intensity.
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 enables a compact, high-resolution handheld confocal microscope with maintained numerical aperture and efficient power management, allowing for precise imaging and reduced artifacts, while the digital control of resonant scanners ensures stable operation and efficient energy use.
Implementation Method 1
the telescope uses a first lens which images or focuses at a position between the scanning mirrors of the scanners
Implementation Method 2
The second lens of the telescope, which is preferably of longer focal length than the first lens thereof, provides with the first lens sufficient magnification to overfill the entrance pupil of the objective over the entire scan angle
Implementation Method 3
resonant scanners which utilize resonant oscillation of a mirror to deflect a laser beam
Implementation Method 4
control systems for resonant scanners utilizing analog drivers in a phase controlled loop have been described in Schermer et al.
Data Source
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AI summary
A confocal microscope having a scanning head in the form of a hand piece (102) which may be placed at selected locations on the body of a patient. A laser beam is scanned in orthogonal (horizontal and vertical) directions by scanners (128, 130) which drive scan mirrors (128a, 130a), which are closely adjacent to each other. The optics include an objective lens (138) and a single telescope lens (132, 134). The telescope provides sufficient magnification to overfill the entrance pupil of the objective lens (138) over the entire scan angle produced by the scan mirrors (128a, 130a). The telescope images (has a focus) in the beam path between the mirrors of the scanners, thereby limiting the distance over the entrance pupil of the objective as the beam executes the scan angle. Scanner (128) represents pulse driven resonant scanner (7) which is pulse driven. The pulse duration is controlled to vary the scan angle and obtain dynamic, electronic image zooming without changing the positional relationship of the telescope lenses.