Pulsed Laser Cavitation Bubble Timing for Shock Wave Generation
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Solution Overview
Problem
Existing methods for cavitation cleaning in confined geometries, such as root canals and blood vessels, are limited by the absence of strong secondary shock waves due to viscous damping and containment factors, leading to inefficient cleaning and disinfection.
Innovation Solution
A laser system delivering pulsed laser energy in sets of multiple pulses, with carefully timed pulse repetition to ensure that subsequent bubbles expand when prior bubbles have contracted, enhancing the emission of shock waves by exerting pressure on collapsing bubbles, thereby increasing the conversion of electromagnetic energy into shock waves for improved cleaning efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If single laser pulses are used to generate cavitation bubbles in confined geometries, then the cleaning process is simple to operate, but strong secondary shock waves are absent due to viscous damping and containment factors, leading to inefficient cleaning and disinfection
Solution Approach 1:
The patent applies periodic action by using multiple laser pulses delivered in sequences with specific pulse repetition times. Each pulse generates a cavitation bubble that oscillates and collapses, and by timing subsequent pulses to coincide with the contraction phase of previous bubbles, strong secondary shock waves are generated. This periodic pulsed action transforms the weak single-pulse cavitation into a series of reinforced shock wave emissions, significantly improving cleaning efficacy while maintaining operational simplicity.
2Productivity
If multiple laser pulses are delivered in sequences with optimized pulse repetition times, then strong secondary shock waves are generated for improved cleaning efficacy, but the system complexity increases due to timing control requirements
Solution Approach 1:
The patent employs parameter changes by systematically varying the pulse repetition time (Tpr) to optimize shock wave generation. Different pulse repetition times are selected based on the characteristics of the liquid medium and the desired cleaning effect. The system adjusts temporal parameters (pulse intervals) to match the natural oscillation periods of cavitation bubbles, thereby maximizing shock wave intensity without requiring complex control mechanisms. This parameter optimization approach enables effective cleaning while keeping the control system relatively simple.
3Power
If pulsed laser energy is delivered in sets of multiple pulses with careful timing, then the conversion of electromagnetic energy into shock waves is enhanced, but the energy consumption increases
Solution Approach 1:
The patent implements continuity of useful action by delivering laser pulses in continuous sequences rather than isolated shots. Each pulse in the sequence contributes to generating shock waves, and the overlapping oscillation cycles of multiple bubbles create a sustained high-energy environment. This continuous pulsed action maintains high shock wave intensity throughout the treatment period, ensuring thorough cleaning of the cavity surfaces while distributing energy delivery over time to manage overall consumption.
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 significantly enhances the cleaning efficacy by generating stronger shock waves within confined spaces, improving the removal of debris and disinfection, even in small liquid reservoirs where prior methods were ineffective.
Implementation Method 1
When energy is locally deposited within a liquid, for example with an intense focused electromagnetic radiation (e.g., laser light)... locally induced boiling of the liquid leads to a creation of a cavitation bubble
Implementation Method 2
laser pulses produce plasma with subsequent bubble formation for ocular surgery by photo-disruption
Implementation Method 3
When the bubble reaches its maximum volume where the internal pressure is lower than in the surrounding liquid the bubble starts to collapse... an intense shock wave may be emitted during the bubble's collapse
Implementation Method 4
These violent cavitation oscillations lead to rapid streaming of liquid molecules around the cavitation bubble... an intense shock wave may be emitted during the bubble's collapse
Implementation Method 5
a cavitation bubble collapsing near a boundary forms a liquid jet directed at the boundary
Implementation Method 6
The strong mechanical forces associated with rapid bubble oscillations can break particles or remove particles from the surface, thus locally cleaning it
Data Source
AI summary
The application relates to a cleaning system configured for cleaning of cavities filled with a liquid, including fragmentation, debridement, material removal, irrigation, disinfection, and decontamination. The cleaning system includes an electromagnetic radiation system and a liquid. A treatment handpiece irradiates the liquid within a cavity with a radiation beam, producing a first vapor bubble using first pulse, and, at a different location, a second vapor bubble using a second pulse. The pulse repetition time is adjusted to ensure efficacy, for example such that an onset time of the second vapor bubble is within the first contraction phase of the first vapor bubble, when the first vapor bubble has contracted from its maximal volume to a size in a range from about 0.7 to about 0.1 of the maximal volume.