Conjugate Lens Focus Control via Beam Separation
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Solution Overview
Problem
Conventional optical systems face challenges in accurately determining focus due to alignment sensitivity of optical components, leading to sub-standard data and wasted samples, especially in diagnostic applications where samples are scarce and time-consuming recalibration is necessary.
Innovation Solution
The optical systems use a conjugate lens to direct incident light beams to a focal region, where the projection relationship of reflected light beams is used to determine focus or profile parameters, such as relative separation, which is indicative of the degree-of-focus, working distance, or surface profile, allowing for automatic adjustment of the object or optical system to achieve proper focus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional focus-control systems use multiple optical components to determine focus, then focus determination capability is achieved, but alignment sensitivity increases and measurement accuracy deteriorates when components move from predetermined positions
Solution Approach 1:
The patent divides the optical measurement function into two independent parts: (1) a reference light beam path that reflects off the object surface to provide focus information, and (2) a separate measurement light beam path that passes through the optical components being tested. This segmentation allows the reference beam to independently verify component alignment without being affected by component movements, thereby maintaining measurement precision and system reliability simultaneously
Solution Approach 2:
The patent introduces a reference light beam as an intermediary that indirectly measures the position of optical components by reflecting off the object surface. Instead of directly measuring component positions (which would be sensitive to component movements), the reference beam serves as a stable mediator that provides consistent focus determination regardless of component alignment changes
2Measurement precision
If complex beam-spot analysis algorithms are used to analyze location, shape, and density of the beam spot, then focus analysis capability is improved, but system complexity and cost increase
Solution Approach 1:
The patent extracts only the essential focus information from the beam spot by measuring the position of the beam spot center relative to a reference position. Instead of using complex algorithms to analyze the entire beam spot morphology (shape, density, etc.), the invention isolates and measures only the critical parameter (beam spot center position), thereby achieving accurate focus determination with simpler, less costly analysis
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 method reduces alignment sensitivity, provides simpler and more accurate focus control, and minimizes data loss and recalibration time, ensuring high-quality data acquisition in applications where samples are limited.
Implementation Method 1
reflecting a reference light beam off a surface of the object and detecting the reflected light beam with a detector
Implementation Method 2
an optical assembly includes a conjugate lens that receives incident light beams and directs the incident light beams to a focal region
Data Source
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AI summary
A method for controlling a focus of an optical system. The method includes providing a pair of incident light beams to a conjugate lens. The incident light beams are directed by the lens to converge toward a focal region. The method also includes reflecting the incident light beams with an object positioned proximate to the focal region. The reflected light beams return to and propagate through the lens. The method also includes determining relative separate measured between the reflected light beams and determining a degree-of-focus of the optical system with respect to the sample based upon the relative separation.