Transparent Workpiece Stack Separation Using Offset Laser Defects
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Solution Overview
Problem
Current methods for cutting and separating glass substrates are inefficient, lacking in speed, cleanliness, cost-effectiveness, and reliability, necessitating the development of alternative techniques for improved processing.
Innovation Solution
A method involving the formation of an optically modified region and a contour with defects in transparent workpieces, utilizing a quasi-non diffracting laser beam to induce absorption and control the laser beam's focal line, allowing for precise separation without sensors or fast-shift focusing optics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional laser cutting methods are used on transparent workpieces, then the workpiece can be separated, but the process is slow and requires precise vertical positioning control
Solution Approach 1:
The patent applies preliminary action by forming an optically modified region in the transparent workpiece before the actual cutting operation. This modification track, created by a first laser beam, changes the optical properties of the material in advance, allowing the second laser beam to selectively form defects only in desired locations without requiring precise vertical positioning during the cutting process itself.
Solution Approach 2:
The patent segments the laser processing into two distinct functional stages: first, creating an optically modified region that serves as a preparation zone, and second, using a separate laser beam to form defects along the cut contour. This segmentation allows each laser beam to have optimized parameters for its specific function, improving overall processing efficiency and eliminating the need for fast-shift focusing optics.
2Power
If high energy laser beams are used to cut through multiple transparent substrates, then cutting power is sufficient, but adjacent substrates may be damaged by the laser beam
Solution Approach 1:
The patent applies local quality by creating an optically modified region with specific optical properties that differ from the surrounding unmodified material. This modification track has altered absorption characteristics that allow it to interact differently with the second laser beam, enabling the high-power laser to cut through multiple substrates while the modified region protects adjacent unmodified substrates from damage by controlling where energy is absorbed.
Solution Approach 2:
The optically modified region acts as an intermediary between the high-power second laser beam and the transparent substrates. This intermediate zone with modified optical properties controls the laser beam's energy distribution, allowing sufficient power to reach and cut through multiple substrates while preventing excessive energy concentration that would damage adjacent areas.
3Manufacturing precision
If traditional cutting methods are used, then equipment is simple, but the separation process is not clean and requires additional processing
Solution Approach 1:
The patent utilizes phase transitions in the form of optical property changes. The first laser beam induces a phase transition in the optical properties of the transparent material, creating an optically modified region with different absorption characteristics. This allows the second laser beam to cleanly separate substrates by forming defects only where needed, achieving high manufacturing precision through controlled optical phase transitions rather than mechanical cutting.
4Measurement precision
If sensors and fast-shift focusing optics are used to achieve precise cutting, then positioning accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies self-service by making the optical system self-aligning through the optically modified region. The modification track created by the first laser beam automatically guides the second laser beam's energy deposition, eliminating the need for external sensors and fast-shift focusing optics to maintain vertical positioning accuracy. The system uses the material's own optical properties to achieve precise defect formation without complex active control mechanisms.
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
Enables faster, cleaner, and more reliable separation of glass substrates by controlling the laser beam's interaction with the workpiece, reducing the need for precise vertical positioning and avoiding damage to adjacent substrates.
Implementation Method 1
a first caustic portion of the primary laser beam is directed into the transparent workpiece, thereby generating an induced absorption within the transparent workpiece, the induced absorption producing a defect within the transparent workpiece
Implementation Method 2
a second caustic portion of the primary laser beam is modified by the optically modified region
Implementation Method 3
The quasi-non diffracting beam comprises a wavelength λ; a spot size wo; and a cross section that comprises a Rayleigh range ZR that is greater than
Data Source
AI summary
A method for processing a transparent workpiece comprises forming an optically modified region in or on a transparent workpiece and forming a contour in the transparent workpiece, the contour comprising a plurality of defects in the transparent workpiece positioned laterally offset from the optically modified region. Forming the contour comprises directing a primary laser beam comprising a quasi-non diffracting beam oriented along a beam pathway onto the transparent workpiece such that a first caustic portion of the primary laser beam is directed into the transparent workpiece, thereby generating an induced absorption within the transparent workpiece to produce a defect within the transparent workpiece and a second caustic portion of the primary laser beam is modified by the optically modified region. Further, translating the transparent workpiece and the primary laser beam relative to each other along a contour line and laterally offset from the optically modified region.