Bessel-Beam Ocular Tissue Cutting for Faster Vertical Planes
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Solution Overview
Problem
Existing femtosecond laser systems for cutting ocular tissues, such as corneas or lenses, are inefficient in forming vertical cutting planes due to misalignment of simultaneously generated impact points, leading to slow operation times and difficulty in detaching crystalline cubes during surgeries like cataract procedures.
Innovation Solution
A cutting apparatus using a femtosecond laser source with a spatial light modulator (SLM) and control unit to apply axiconic modulation, generating a Bessel-type modulated laser beam for precise, oblong gas bubble formation, allowing faster and more efficient vertical cutting planes by controlling the phase and intensity profile of the laser beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional Gaussian laser beam is used to form vertical cutting planes, then the laser can cut tissue, but the operation time is long and the cutting efficiency is low
Solution Approach 1:
The patent segments the laser beam into multiple parallel beams using a diffractive optical element, allowing simultaneous cutting at multiple locations. This transforms a single-point sequential cutting process into a multi-point parallel process, directly improving cutting speed and reducing operation time.
Solution Approach 2:
The patent introduces a new dimension by using a diffractive optical element to create multiple impact points distributed in space. Instead of moving a single beam along a linear path, the system creates a two-dimensional array of simultaneous cutting points, dramatically increasing productivity.
2Productivity
If multiple impact points are generated simultaneously to increase cutting speed, then productivity improves, but misalignment of impact points occurs leading to poor cutting quality
Solution Approach 1:
The patent incorporates a control unit that coordinates the timing and positioning of multiple laser beams. By synchronizing the generation and scanning of parallel beams, the system maintains precise alignment of impact points, ensuring cutting quality while achieving high-speed parallel processing.
Solution Approach 2:
The patent replaces mechanical alignment methods with optical diffraction principles. The diffractive optical element inherently distributes the beam into precise geometric patterns, eliminating the need for complex mechanical positioning systems and ensuring consistent alignment accuracy.
3Manufacturing precision
If the laser beam is focused to a small spot to achieve precise cuts, then cutting precision is maintained, but the area covered per pulse is small requiring many sequential impacts
Solution Approach 1:
The patent segments the focused laser energy into multiple parallel beams, each maintaining the precision of a focused spot while collectively covering a larger area. This allows the system to perform many cuts simultaneously rather than sequentially, dramatically improving efficiency without sacrificing precision.
Solution Approach 2:
The patent merges multiple focused beams into a coordinated array that operates in unison. By combining the precision of focused spots with the parallelism of multiple beams, the system achieves both high precision and high efficiency that cannot be obtained with a single beam alone.
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 apparatus significantly reduces the time required for cutting vertical planes by utilizing a Bessel-type beam, ensuring precise and high-quality cuts with self-regeneration properties, minimizing energy loss and maintaining cut surface quality.
Implementation Method 1
a shaping system positioned in the path of the Gaussian laser beam, for modulating the phase of the wavefront of the Gaussian laser beam, the shaping system comprising a spatial light modulator (SLM) and being configured to produce a modulated laser beam from the Gaussian laser beam
Implementation Method 2
when focusing the laser beam into the cornea, a plasma is generated by non-linear ionization when the laser intensity exceeds a threshold value, called the optical breakdown threshold. A gas bubble then forms, causing a very localized disruption of the surrounding tissue
Implementation Method 3
a scanning device 4, composed of controllable galvanometric mirrors, and/or stages allowing the movement of optical elements
Implementation Method 4
a focusing optical system downstream of the shaping system, for focusing the modulated laser beam into a focal plane of the cutting apparatus and for moving the focal plane of the cutting apparatus to a plurality of positions
Data Source
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AI summary
The invention relates to a cutting apparatus including a femtosecond laser source (10) for emitting a Gaussian laser beam, a shaping system (30) including a spatial modulator of light for modulating the Gaussian laser beam, a sweeping optical scanner (40) for moving the modulated laser beam, an optical focusing system (50) for focusing the modulated laser beam, characterised in that the processing device further comprises a control unit (60) for controlling the femtosecond laser source (10), the shaping system (30), the sweeping optical scanner (40) and the optical focusing system (50), in order to produce: - at least one vertical cutting plane, and - at least one horizontal cutting plane; the spatial light modulator of the shaping system (30) being capable of emulating an axicon for generating a Bessel beam.