Microscope Optical Element for Off-Axis Light Detection
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Solution Overview
Problem
Multi-photon excitation laser scanning microscopes face a significant decrease in detection efficiency for off-axis light beams when observing deep tissue due to scattering and the angular response of photodetectors, particularly because the pupil of the objective is projected onto a smaller light-receiving surface, increasing the beam angle and reducing detection efficiency.
Innovation Solution
The microscope apparatus incorporates an optical element with refractive surfaces arranged orthogonally to the optical axis, which converts incident light fluxes from the objective's pupil to become nearly parallel to the axis, and a relay optics system that projects this optical element onto the photodetector, reducing the beam angle and enhancing detection efficiency without increasing the photodetector's light-receiving surface size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pupil of the objective is projected onto a smaller light-receiving surface of the photodetector, then the detection efficiency for off-axis light beams decreases due to increased beam angle, but the photodetector size can be kept compact
Solution Approach 1:
The patent introduces a beam angle conversion optical element as an intermediary between the objective and photodetector. This element converts the beam angle of incident light fluxes without requiring an increase in the photodetector's light-receiving surface area, thereby resolving the contradiction between maintaining compact detector size and preserving detection efficiency for off-axis light beams
Solution Approach 2:
The patent changes the beam angle parameter of incident light fluxes using the optical element with specific refractive surfaces. By transforming the angular parameter of the light while maintaining the same photodetector surface size, the system achieves improved detection efficiency without increasing the detector's physical dimensions
2Reliability
If an optical element with multiple refractive surfaces is introduced to convert beam angles, then detection efficiency for off-axis light improves, but the device complexity increases
Solution Approach 1:
The patent merges the beam angle conversion function with the existing optical path by integrating the optical element into the relay optics system. This combination approach achieves beam angle conversion without adding separate independent components, thereby reducing overall device complexity while maintaining improved detection efficiency
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 effectively suppresses the decrease in detection efficiency caused by the angular response of the photodetector, allowing for brighter fluorescent images by reducing the beam angle of incident light fluxes, thereby improving the detection of both on-axis and off-axis light without enlarging the photodetector's surface.
Implementation Method 1
an optical element with refractive surfaces arranged orthogonally to the optical axis, which converts incident light fluxes from the objective's pupil to become nearly parallel to the axis
Data Source
AI summary
A microscope apparatus includes an objective and a photodetector, and projects a pupil of the objective onto a light-receiving surface of the photodetector. The microscope apparatus further includes an optical element that is arranged between the objective and the photodetector. The optical element has a plurality of refractive surfaces which are arranged in a direction orthogonal to an optical axis of the optical element and to which light fluxes emitted from the pupil of the objective at different angles are incident.