Ultrashort Pulse Laser Capsule Marking Without Thermal Damage
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Solution Overview
Problem
Existing methods for marking pharmaceutical capsules are inadequate as they often cause thermal damage and fail to produce precise, indelible identifiers that are optically readable.
Innovation Solution
The use of ultrashort pulse laser marking apparatuses that employ a laser transmission element with a pulse duration less than 10 picoseconds and a wavelength of less than 1.5 microns, coupled with beam steering or masking elements, to create indelible identifiers on pharmaceutical capsules using photoreactive pigments that change color or form patterns with light interface elements, ensuring optical readability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional laser marking methods are used, then marking speed and productivity are maintained, but thermal damage occurs to the capsule surface and marking precision deteriorates
Solution Approach 1:
The patent employs ultrashort pulse laser marking with pulse durations of 1-100 picoseconds, delivering energy in extremely short periodic bursts rather than continuous exposure. This periodic action allows the material to cool between pulses, preventing thermal accumulation and damage while maintaining precise marking capability through high peak power delivery.
Solution Approach 2:
The invention changes critical laser parameters including pulse duration (1-100 ps), wavelength (355-1064 nm), and peak power density to achieve cold ablation. By adjusting these parameters, the laser interacts with the capsule shell material through non-thermal mechanisms, enabling precise marking without the thermal damage associated with conventional continuous-wave or long-pulse laser systems.
2Measurement precision
If conventional laser marking is used, then equipment complexity is reduced, but the ability to create optically readable identifiers deteriorates
Solution Approach 1:
The patent introduces photoreactive pigments as an intermediary substance applied to the capsule shell before marking. These pigments contain chromophores that undergo photochemical reactions when exposed to specific laser wavelengths, creating high-contrast optically readable identifiers. The pigments mediate the laser-material interaction, enhancing optical readability without requiring complex laser systems.
Solution Approach 2:
The invention replaces mechanical contact marking methods with optical field-based ultrashort pulse laser marking. This substitution eliminates mechanical wear and contamination while achieving superior precision and optical readability through photodisruption and photochemical effects, reducing the need for complex mechanical positioning and marking mechanisms.
3Reliability
If longer pulse duration lasers are used, then energy delivery is more efficient, but thermal damage increases and marking durability decreases
Solution Approach 1:
The system uses ultrashort pulse durations (1-100 ps) to deliver laser energy in extremely brief periodic bursts. This allows the capsule shell material to undergo photodisruption and photochemical changes without significant heat diffusion, creating durable markings through cold ablation mechanisms that prevent thermal damage to surrounding areas.
Solution Approach 2:
The ultrashort laser pulses induce phase transitions in the capsule shell material through photodisruption and photochemical reactions rather than thermal melting. The photoreactive pigments undergo rapid molecular structure changes when exposed to the laser, creating permanent, durable markings through non-thermal phase transitions that preserve material integrity.
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 allows for precise, thermal-damage-free marking of pharmaceutical capsules with optically readable identifiers, enhancing the accuracy and durability of the marking process.
Implementation Method 1
The beam of laser energy may have a pulse duration of less than 10 picoseconds and a wavelength of less than 1.5 microns
Implementation Method 2
The consumable article may comprise a photoreactive pigment configured to undergo a color change upon exposure to a beam of laser energy
Implementation Method 3
coupled with beam steering or masking elements, to create indelible identifiers
Implementation Method 4
The consumable article may comprise a photoreactive pigment configured to undergo a color change upon exposure to a beam of laser energy
Data Source
AI summary
Embodiments of an ultrashort pulse laser marking apparatus for forming indelible identifiers on discreet consumable articles, and corresponding methods, are disclosed. An ultrashort pulse laser transmission element of the apparatus is configured to transmit a beam of laser energy toward a marking zone to form an optically-readable indelible identifier on discrete consumable articles. The beam may have a pulse duration less than 10 picosecond, and a wavelength of less than 1.5 microns. The consumable articles may comprise a photoreactive pigment configured to undergo a color change upon exposure to the beam of laser energy, and the indelible identifier may be defined by the color change. Alternatively or in addition, the optical readability may be at least in part by way of a primary pattern reflected light intensity being distinguishable from a baseline reflected light intensity or from a secondary reflected light intensity from a viewpoint outward of the article.