Tilted Projection Optical Unit for Variable Depth Laser Tissue Cuts
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Solution Overview
Problem
Existing ophthalmological devices using pulsed laser beams struggle to make tissue cuts with a vertical cut component due to the slow vertical movement of the projection optical unit, which limits the ability to create cuts with a variable depth of focus.
Innovation Solution
The device incorporates a tilting mechanism for the projection optical unit about an axis perpendicular to the scanning plane, allowing the focus of the laser pulses to be displaced without vertical displacement of the unit, enabling cuts with a vertical component by tilting the scanning line within a defined angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the projection optical unit is moved vertically to create cuts with a vertical component, then the ability to make cuts with variable depth of focus is improved, but the processing speed deteriorates due to the slow mechanical movement
Solution Approach 1:
The patent replaces the mechanical vertical movement system with an optical scanning system. Instead of physically moving the projection optical unit vertically, the invention uses a scanner system with deflection mirrors to steer the laser beam and create vertical cuts through optical means, thereby eliminating the speed limitation of mechanical movement while maintaining the capability to produce cuts with vertical components at variable depths.
Solution Approach 2:
The patent introduces a scanning dimension through the use of deflection mirrors that can steer the laser beam in multiple directions. By adding this optical scanning dimension, the system can achieve vertical cut components without relying on slow mechanical vertical translation, effectively solving the contradiction by operating in an additional dimensional space (angular/scan space rather than linear mechanical space).
2Adaptability or versatility
If the projection optical unit is moved vertically to vary the focus height, then the capability to create cuts at different depths is improved, but the response time deteriorates due to the slow mechanical displacement
Solution Approach 1:
The patent substitutes the mechanical focus adjustment mechanism with an optical scanning mechanism. The scanner system with deflection mirrors enables rapid changes in beam direction and focus position without the inertia and speed limitations of mechanical movement, allowing the system to quickly adapt to different cutting depths and respond in real-time to varying surgical requirements.
Solution Approach 2:
The patent transforms the static or slowly adjustable mechanical focus system into a dynamic optical system. The scanner mirrors can rapidly change their angular positions to dynamically adjust the focus height and cutting depth, enabling real-time adaptability without the time delays inherent in mechanical displacement systems.
3Area of stationary object
If a mechanically moved projection optical unit is used to cover a large processing region, then the coverage area is improved, but the scanning speed for fine movements deteriorates
Solution Approach 1:
The patent divides the scanning function into two independent components: a mechanical positioning system for covering the large processing region and an optical scanner system for rapid fine scanning movements. This segmentation allows each subsystem to optimize for its specific function—the mechanical system for broad coverage and the optical scanner for high-speed detailed scanning—thereby resolving the contradiction between coverage area and scanning speed.
Solution Approach 2:
The patent combines two different scanning approaches into a unified system: mechanical movement of the projection optical unit for coarse positioning and beam deflection by scanner mirrors for fine scanning. By merging these two methods, the system achieves both large-area coverage and high-speed scanning capability, with each method complementing the other's strengths.
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 enables precise tissue cuts with a vertical component without requiring vertical displacement of the projection optical unit, improving the ability to create cuts with variable depth of focus, enhancing the device's capability to process eye tissue effectively.
Implementation Method 1
The deflection of the light beams or of the laser pulses, for example femtosecond laser pulses, is generally performed by means of movable mirrors which are pivotable about one or two scanning axes
Implementation Method 2
a projection optical unit for the focused projection of the laser beam or of the laser pulses into the eye tissue
Data Source
AI summary
For processing eye tissue using a pulsed laser beam (L), an ophthalmological device includes a projection optical unit for the focused projection of the laser beam (L) into the eye tissue, and a scanner system upstream of the projection optical unit for the beam-deflecting scanning of the eye tissue with the laser beam (L) in a scanning movement (s′) performed over a scanning angle along a scanning line(s). The projection optical unit is tilted about an axis of rotation (q) running perpendicularly to a plane defined by the scanning line(s) and the optical axis (o) of the projection optical unit, the tilting of the projection optical unit tilting the scanning line (s) in said plane. Tilting of the scanning line(s) enables a displacement—dependent on the scanning angle—of the focus of the laser pulses projected into the eye tissue without vertical displacement of the projection optical unit.