Dual Rotatable Diffractive Optical Elements for Laser Beam Grouping
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Solution Overview
Problem
Existing methods for splitting laser beams to perform multiple scribing processes in parallel, such as in one-step interconnection for thin film solar panels, face limitations in varying the separation of scribe lines and efficiency in dual-stage groove formation processes.
Innovation Solution
The use of two rotatable diffractive optical elements (DOEs) in series, where the first DOE splits a laser beam into sub-beams and the second DOE further splits these into groups of sub-beams, allowing for adjustable separation of both the groups and sub-beams, enabling precise control over spot spacing and flexibility in scribing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single diffractive optical element (DOE) is used to split laser beams, then the device complexity is low, but the ability to independently adjust spot spacing within and between groups is limited
Solution Approach 1:
The patent divides the beam splitting function into two separate DOEs: the first DOE splits the laser beam into multiple sub-beams, and the second DOE further splits these sub-beams into groups. This segmentation allows independent control of spot spacing within groups (via first DOE rotation) and between groups (via second DOE rotation), resolving the limitation of single-DOE systems while maintaining manageable device complexity through functional decomposition.
2Adaptability or versatility
If the distance between DOE and lens is fixed to achieve parallel output beams, then the ease of operation is improved, but the ability to vary scribe line separation is limited
Solution Approach 1:
The patent introduces rotational degrees of freedom to both DOEs, transforming the static beam splitting system into a dynamic one. By rotating the first DOE, the separation of spots within each group can be adjusted; by rotating the second DOE, the separation between groups can be adjusted. This dynamic adjustment capability allows variable scribe line separation while maintaining the fixed DOE-lens distance configuration for parallel beam output.
3Productivity
If laser beams are split into fixed groups, then the manufacturing precision is maintained, but the productivity in dual-stage groove formation processes is reduced
Solution Approach 1:
The patent creates a universal beam splitting system where the two-DOE configuration serves multiple functions: it can form multiple groups of parallel beams for high-speed parallel scribing, adjust spot spacing within groups for different pattern requirements, and adjust separation between groups for varying scribe line densities. This multi-functionality enables the system to adapt to different dual-stage groove formation processes and productivity requirements without requiring separate specialized systems.
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 configuration provides greater flexibility and precision in controlling the separation of laser spots on a substrate, enabling independent adjustment of spot spacing within and between groups, enhancing the efficiency of parallel scribing processes, particularly in thin film solar panel interconnection.
Implementation Method 1
a first diffractive optical element (DOE) arranged to receive a first laser beam and to divide this into a plurality of second laser sub-beams
Implementation Method 2
a second DOE being arranged to receive said plurality of second laser sub-beams and to divide each of these into two or more groups of third laser sub-beams
Implementation Method 3
the separation of the groups in a direction perpendicular to a first axis being adjustable by rotation of the first DOE about its optical axis
Implementation Method 4
the separation of the third laser sub-beams within each group in a direction perpendicular to the first axis being adjustable by rotation of the second DOE about its optical axis
Data Source
Figure 1~2
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AI summary
An apparatus for and a method of forming a plurality of groups of laser beams (2, 2', 2") are defined. Each group (2, 2', 2")may comprise two or more laser beams. The apparatus comprises a first diffractive optical element (3, referred as DOE) and a second diffractive optical element (8), the first DOE (3) being arranged to receive a first laser beam (1) and to divide this into a plurality of second laser sub-beams and the second DOE (8) being arranged to receive said plurality of second laser sub-beams and to divide each of these into two or more groups of third laser sub-beams (2, 2', 2"), the separation of the groups in a direction perpendicular to a first axis being adjustable by rotation of the first DOE (3) about its optical axis and the separation of the third laser sub-beams (2, 2', 2") within each group in a direction perpendicular to the first axis being adjustable by rotation of the second DOE (8) about its optical axis.