Asynchronous Autofocus Module for Optical Instruments
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Solution Overview
Problem
Traditional autofocus subsystems in optical instruments disrupt other operations by interrupting scanning processes and are prone to z-axis drift due to discrete operation intervals, leading to instability in maintaining precise focus over time.
Innovation Solution
A continuously operating, asynchronously functioning autofocus module that monitors and adjusts the z-axis position of the objective lens relative to the sample, using a beam splitter to split the autofocus light into multiple downstream beams of varying optical path lengths, allowing for simultaneous monitoring and correction of focus deviations without interrupting other operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional autofocus subsystems operate at discrete intervals to maintain focus, then the system can periodically correct focus deviations, but this causes interruptions to scanning processes and introduces z-axis drift between correction intervals
Solution Approach 1:
The patent implements continuous autofocus operation where the autofocus subsystem runs asynchronously and continuously rather than at discrete intervals. This allows the system to maintain focus without interrupting scanning processes, as the continuous operation eliminates the start-stop cycles inherent in traditional periodic autofocus systems.
Solution Approach 2:
The system dynamically adjusts the z-axis position of the objective lens in real-time based on continuous feedback from the detector. This dynamic adjustment capability allows the system to respond to focus deviations immediately without waiting for predetermined correction intervals, thereby maintaining both focus stability and scanning continuity.
2Measurement precision
If traditional autofocus systems use a single optical path for focus detection, then the system structure remains simple, but it cannot simultaneously monitor multiple focal planes or perform rapid z-axis position determination
Solution Approach 1:
The patent segments the single optical path into multiple parallel optical paths using beam splitters. Each optical path is directed to a different detector, allowing simultaneous monitoring of multiple focal planes. This segmentation enables rapid z-axis position determination by comparing signals from multiple detectors without requiring sequential scanning.
Solution Approach 2:
The system transitions from monitoring a single focal plane to simultaneously monitoring multiple focal planes by adding the dimension of parallel optical paths. This dimensional expansion allows the system to determine z-axis position more rapidly by analyzing focus information from multiple planes concurrently, rather than sequentially.
3Ease of operation
If the autofocus subsystem operates synchronously with scanning processes, then coordination between focus adjustment and scanning is simplified, but focus corrections may disrupt or slow down the scanning rate
Solution Approach 1:
The autofocus subsystem operates asynchronously and independently from the scanning process, dynamically adjusting focus without being synchronized to scanning cycles. This dynamic operation allows the autofocus system to work at its own optimal rate without being constrained by scanning timing, thereby maintaining high scanning rates while ensuring continuous focus correction.
Solution Approach 2:
The patent introduces an intermediary control system that manages the asynchronous operation between the autofocus subsystem and the scanning process. This intermediary coordinates the independent operations by translating focus correction signals into adjustments that do not disrupt the scanning rhythm, allowing both processes to run simultaneously at full speed.
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 solution maintains stable and precise focus over time without disrupting data collection, reducing z-axis drift and enabling faster and more accurate determination of the z-axis position, thus enhancing the stability and precision of optical instrument focus.
Implementation Method 1
uses a beam splitter to split the autofocus light into multiple downstream beams of varying optical path lengths
Data Source
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AI summary
Embodiments of the present invention are directed to autofocus subsystems within optical instruments that continuously monitor the focus of the optical instruments and adjust distances within the optical instrument along the optical axis in order to maintain a precise and stable optical-instrument focus at a particular point or surface on, within, or near a sample. Certain embodiments of the present invention operate asynchronously with respect to operation of other components and subsystems of the optical instrument in which they are embedded. In one embodiment the autofocus detector comprises a beam splitter arranged to split the autofocus light beam into a plurality (n) of down-stream light beams and a photodetector arrangement for registering the intensity of each one of the down-stream light beams.