Microscope Beam-Shift Mechanism for Wavefront Scanning
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Solution Overview
Problem
Conventional scanning confocal microscope apparatuses face challenges in maintaining light focusing ability when scanning illuminating light across a specimen, especially when the wavefront of the light is modulated, leading to non-uniform display and insufficient light intensity due to displacement of the laser beam from the objective lens's pupil center.
Innovation Solution
A microscope apparatus featuring a spatial light modulator that modulates the wavefront of illuminating light, a scanner with two independently pivoted mirrors, and a relay optical system with a beam-shift mechanism that compensates for mirror pivoting by moving the light rays in a direction intersecting the optical axis, ensuring the image at the objective optical system's pupil position remains stationary, thus maintaining focus and maximizing light intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a galvanometer mirror is translated in the optical-axis direction in synchronization with pivoting, then the laser beam can be made constantly incident on the center of the pupil of the objective lens, but the light focusing ability changes when light whose wavefront is modulated is used
Solution Approach 1:
Instead of translating the galvanometer mirror to maintain beam position (conventional approach), this invention translates the objective lens in the optical-axis direction. This inverted approach achieves the same goal of maintaining constant optical path length while avoiding the harmful effect of changing light focusing ability for modulated wavefronts
Solution Approach 2:
The invention introduces a beam-shift mechanism as an intermediary component between the scanner and the objective lens. This mechanism compensates for the beam displacement caused by mirror pivoting, allowing the system to maintain both beam centering and constant optical path length without directly translating the galvanometer mirror
2Ease of operation
If the optical path length is varied by translating the galvanometer mirror, then the beam position can be maintained, but the position optically conjugate with the pupil position varies, changing the light focusing ability
Solution Approach 1:
The invention inverts the conventional approach by translating the objective lens instead of the galvanometer mirror. This maintains the beam position at the pupil center while keeping the optical path length constant, thereby preserving focus precision for modulated wavefronts
Solution Approach 2:
The invention changes the parameter being varied (from mirror position to lens position) while maintaining the same functional outcome. By translating the objective lens instead of the mirror, the system achieves beam positioning without altering the optical path length, thus maintaining focus precision
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 two-dimensional scanning of light across a specimen without degrading the light focusing ability, ensuring maximum brightness and precise focusing by compensating for wavefront changes and optical aberrations, even with non-plane wavefronts, thereby obtaining sharp fluorescence images.
Implementation Method 1
a spatial light modulator that modulates the wavefront of illuminating light from a light source
Implementation Method 2
a scanner that has two mirrors independently pivoted about two non-parallel axes and thus two-dimensionally scans the illuminating light whose wavefront has been modulated
Implementation Method 3
a relay optical system that relays an image in the scanner to a pupil position of an objective optical system
Implementation Method 4
a beam-shift mechanism that moves rays of the illuminating light in a direction intersecting the optical axis, in response to pivoting of the mirrors
Implementation Method 5
an objective optical system that focuses the laser beam L relayed by the relay optical system L
Implementation Method 6
a photodetector that detects fluorescence coming from the specimen A
Data Source
AI summary
Illuminating light is two-dimensionally scanned without changing the ability to focus the illuminating light on a specimen. Provided is a microscope apparatus including a spatial light modulator that modulates the wavefront of illuminating light; a scanner that two-dimensionally scans the illuminating light by pivoting two mirrors; a relay optical system that relays an image in the scanner to a pupil position of an objective optical system; and a beam-shift mechanism that moves rays of the illuminating light between the modulator and the objective optical system in response to pivoting of the mirrors. The beam-shift mechanism moves the rays such that the image at the pupil position, when assuming that the mirrors are stationary, is moved in the direction opposite to the direction in which the image relayed to the pupil position by the relay optical system, when assuming that the mirrors are pivoted with the rays fixed, is moved.