Microscope Illumination Optical System with Movable Field Stop
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Solution Overview
Problem
Conventional illumination optical systems for microscopes require frequent adjustments in magnification, leading to increased operational load on users, as they need to switch between high and low magnification settings, which affects the illumination environment and resolution.
Innovation Solution
A both-side telecentric illumination optical system comprising a collector lens, field stop, field lens with positive power, aperture stop, and collective lens, configured to satisfy specific conditional expressions for maintaining adequate illumination range and resolution across varying magnifications, reducing the need for magnification adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional illumination optical systems are used with magnification changes, then the illumination environment can be optimized for specific magnifications, but the operational load on users increases due to frequent adjustments
Solution Approach 1:
The illumination optical system is designed to provide both high NA illumination for high magnification and wide field-of-view illumination for low magnification using a single integrated system. The key is the movable field stop that can be positioned at different locations along the optical path, allowing the same optical components to serve multiple functions across different magnification ranges without requiring separate illumination systems or manual adjustments.
2Measurement precision
If high magnification observation is performed, then resolution is improved, but the illumination range becomes narrower requiring high NA
Solution Approach 1:
The field stop is designed to be movable along the optical path rather than fixed. By dynamically repositioning the field stop to different locations, the system can adjust the illumination characteristics to match the observation requirements. For high magnification, the field stop is positioned to provide high NA for resolution; for low magnification, it is repositioned to provide wide field-of-view illumination.
3Area of stationary object
If low magnification observation is performed, then the observation range is wider, but high resolution is not needed
Solution Approach 1:
The movable field stop allows the illumination system to adapt its characteristics dynamically. When observing at low magnification where wide field-of-view is needed, the field stop is repositioned along the optical path to provide appropriate illumination geometry that covers the wider area without requiring high NA, thus matching the lower resolution requirements of low magnification observation.
4Measurement precision
If immersion objective is used for high magnification exceeding 400×, then resolution is improved, but additional operations are required to wipe off oil
Solution Approach 1:
The illumination optical system is designed to provide high NA illumination (0.8≧NA≧0.5) that can effectively support high magnification observation up to 400× and beyond without requiring immersion objectives. By providing sufficient illumination NA through the movable field stop configuration, the system achieves the necessary resolution for high magnification while avoiding the need for immersion oil and the associated cleaning operations.
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 solution eliminates the need for frequent adjustments between magnifications, reducing the operational load on users by maintaining optimal illumination and resolution from 20× to 400× magnification, thereby enhancing user experience and efficiency.
Implementation Method 1
a field lens having positive power, an aperture stop, and a collective lens having positive power
Implementation Method 2
can be a substantially both-side telecentric optical system between the field stop and a sample surface
Data Source
AI summary
An illumination optical system includes, in order from a light source side a collector lens, a field stop, a field lens having positive power, an aperture stop, and a collective lens having positive power. The illumination optical system is a substantially both-side telecentric optical system between the field stop and a sample surface, and satisfies the following conditional expressions where DFS indicates a diameter of the field stop, β indicates a magnification from the sample surface to the field stop, and NA indicates a numerical aperture on the sample surface side of the illumination optical system.15≧DFS/β≧9 (1)0.85≧NA≧0.5 (2)