Hybrid Mode Laser Diode Focus Tracking
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Solution Overview
Problem
Existing optical scanning systems face challenges in achieving accurate and rapid focus tracking due to issues with spot size variability and unwanted reflections from multi-layer sample containers, which increase latency and reduce focus tracking accuracy.
Innovation Solution
The implementation of a laser diode operating in a hybrid mode, with a power level above the lasing threshold but below the ASE mode, combined with the use of a roof prism and beam blockers to stabilize spot separation and reduce fringing, and the placement of blocking structures to eliminate unwanted reflections, improves focus tracking accuracy and reduces latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a laser diode operates at high power level for single mode operation, then focus tracking speed is improved, but spot size variability and fringing increase reducing accuracy
Solution Approach 1:
The patent applies parameter changes by operating the laser diode in a hybrid mode between ASE and single mode, adjusting the power level to a specific range (2-10% above lasing threshold) to achieve optimal balance between speed and accuracy. This intermediate parameter setting resolves the contradiction by avoiding both extremes of high power (which causes fringing) and low power (which reduces tracking speed).
Solution Approach 2:
The patent introduces local quality by adding roof prisms and beam blockers at specific locations in the optical path to address spot size variability and fringing locally. These components are strategically placed to stabilize spot separation and reduce unwanted reflections without affecting the overall laser power level, thereby improving accuracy while maintaining tracking speed.
2Measurement precision
If a multi-beam focus track system is used to determine focus distances, then focus accuracy is improved, but latency increases reducing system speed
Solution Approach 1:
The patent resolves this contradiction by changing the laser operating parameters to hybrid mode, which stabilizes spot separation and reduces the number of measurements needed to achieve accurate focus determination. This reduces the time required for focus calculation while maintaining high accuracy, effectively lowering latency without sacrificing precision.
3Loss of time
If laser power is increased to reduce exposure time, then focus tracking latency is reduced, but fringing and spot stability deteriorate
Solution Approach 1:
The patent applies parameter changes by setting the laser power to an optimal intermediate level in hybrid mode (2-10% above lasing threshold). This parameter optimization allows the system to achieve sufficient signal intensity for fast exposure times while maintaining spot stability and minimizing fringing, thus resolving the contradiction between speed and stability.
4Measurement precision
If blocking structures are added to eliminate unwanted reflections, then focus tracking accuracy is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by introducing blocking structures (beam blockers and roof prisms) at specific strategic locations in the optical path where unwanted reflections occur. These localized components address the reflection problem precisely where it affects focus tracking accuracy, rather than requiring a complete system redesign, thus improving accuracy with minimal increase in overall complexity.
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 approach results in more stable spot separation, reduced fringing, and improved focus tracking accuracy, enabling faster and more precise focus determination in optical scanning systems.
Implementation Method 1
The laser diode light source may be operated at a power level that is above a power level for operation at an Amplified Spontaneous Emission ('ASE') mode, but below a power level for single mode operation
Implementation Method 2
an objective lens positioned to direct a focus tracking beam from the light source onto a location in a sample container
Implementation Method 3
combined with the use of a roof prism and beam blockers to stabilize spot separation and reduce fringing
Implementation Method 4
the image sensor may further include a plurality of pixel locations to receive a focus tracking beam that is reflected off of the location in the sample container
Data Source
AI summary
Systems and methods disclosed herein include an imaging system that may include a laser diode source; an objective lens positioned to direct a focus tracking beam from the light source onto a location in a sample container and to receive the focus tracking beam reflected from the sample; and an image sensor that may include a plurality of pixel locations to receive focus tracking beam that is reflected off of the location in the sample container, where the reflected focus tracking beam may create a spot on the image sensor. Some examples may further include a laser diode light source that may be operated at a power level that is above a power level for operation at an Amplified Spontaneous Emission (“ASE”) mode, but below a power level for single mode operation.