Microscope Objective Phase Plate Air Space Design
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Solution Overview
Problem
Microscope objectives with smaller image scales face challenges in image contrast due to scattered light from high reflection at phase structures, leading to increased production complexity and constructional length in existing solutions.
Innovation Solution
A phase plate is arranged between the first two lenses or groups of lenses, shifting the real pupil into an air space, where the phase ring is vapor-deposited on one plate, minimizing scattered light by impinging beams at an angle, and using the same lenses for both bright-field and phase contrast variants with mechanical adaptations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a phase plate with metal layers is inserted at the real pupil location, then image contrast is improved, but scattered light increases due to high reflection
Solution Approach 1:
An air space is introduced as an intermediary between the first two lens groups, allowing the phase plate to be positioned where beams are inclined rather than parallel. This intermediary space enables the phase plate to function while reducing direct perpendicular reflection that causes scattered light.
Solution Approach 2:
The position of the real pupil is shifted from its conventional location to an air space between lens groups by changing the optical parameters (refractive powers) of the individual lenses. This parameter change moves the phase plate to a location where beams impinge at an angle, reducing scattered light.
2Object-generated harmful factors
If the real pupil is shifted into an air space between lenses, then scattered light is reduced, but manufacturing complexity increases
Solution Approach 1:
The same lens assembly is designed to serve multiple functions: it can operate as a bright-field objective or be converted to a phase contrast objective by simply inserting a phase plate into the air space. This universal design reduces manufacturing complexity by avoiding the need for completely different lens systems.
Solution Approach 2:
The objective allows dynamic configuration where the phase plate can be inserted or removed from the air space, enabling conversion between bright-field and phase contrast modes. This dynamic adaptability simplifies production by using a single base design for multiple applications.
3Object-generated harmful factors
If phase structures are applied onto curved surfaces, then scattered light is reduced, but production costs increase
Solution Approach 1:
Instead of curving the phase plate surfaces, the invention changes the positional parameter of the real pupil to an air space where inclined beams naturally reduce scattered light. This allows the phase plate to maintain simple planar surfaces, greatly simplifying manufacturing and reducing costs.
4Length of stationary object
If a phase plate is arranged between the first two lenses, then constructional length is reduced, but imaging error correction becomes more difficult
Solution Approach 1:
The refractive powers of the individual lenses are carefully adjusted to compensate for the displacement of the real pupil. By changing these optical parameters, the design achieves optimal compromise between short constructional length and proper correction of imaging errors like field curvature and astigmatism.
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 reduces scattered light, achieves improved image contrast, and simplifies production while maintaining a short constructional length, allowing for easy conversion between bright-field and phase contrast modes with reduced manufacturing costs.
Implementation Method 1
The phase ring is vapor-deposited on one of the two planar plates
Implementation Method 2
a specific structure is applied onto the cement surface so as to manipulate amplitude and phase. In doing so, zeroth order beams are attenuated, and the beams of higher orders receive a 90° phase jump
Implementation Method 3
The scattered light caused by double reflection at the phase ring (very high reflectance) as well as by the external surfaces of the glass plates is minimized, so that an improvement in image contrast is obtained
Data Source
AI summary
A microscope objective having at least four lenses or groups of lenses and which can be used to improve image contrast. According to the invention, a phase plate, aligned concentrically to the optical axis, can be integrated into and taken out of the air space between the first lens and the second lens, as viewed from the object side. The defined arrangement of the phase plate and the associated shift of the real pupil into the air space between the first two lenses or groups of lenses, respectively, of the microscope objective allows a microscope objective, initially designed as a bright-field variant, to be redesigned as a phase contrast variant with relative ease.