Defocused Laser Machining Printing Stencil Carrier Layer Openings

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Solution Overview

Problem

Conventional printing screens for solar cell printing are time-consuming and costly to produce, with limitations in achieving uniformity and aspect ratio of contact fingers due to screen fabric constraints, leading to inefficiencies in energy transfer and stencil durability.

Innovation Solution

A method using a defocused laser beam to machine carrier layer openings in printing stencils, allowing for wider openings and reduced web widths, which simplifies and accelerates the production process while maintaining stencil stability and print quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional focused laser beam cutting is used to machine carrier layer openings, then cutting precision is maintained, but production time and cost increase significantly

Engineering Contradiction:
Improvecarrier layer opening precisionVSAvoidproduction time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent changes the focusing parameter of the laser beam from focused to defocused state. This parameter change allows the laser beam to machine wider carrier layer openings more efficiently, reducing production time while maintaining adequate precision for the application requirements.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The defocused laser beam creates slightly wider carrier layer openings than the minimum required. This excessive action in terms of opening width compensates for the reduced precision, ensuring sufficient print quality while dramatically improving production efficiency.

Inventive Principle:
Principle #16Partial or excessive action

2Stability of the object's composition

If screen fabric is used in printing screens, then structural stability is provided, but uniformity of paste application and aspect ratio of contact fingers deteriorate

Engineering Contradiction:
Improveprinting screen stabilityVSAvoidcontact finger uniformity
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent removes the screen fabric component from the printing screen structure. By extracting this problematic element, the uniformity of paste application and aspect ratio of contact fingers are significantly improved, while the carrier layer alone provides sufficient structural stability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses a composite structure with a carrier layer and structural layer without screen fabric. This composite design achieves both stability and precision by combining the mechanical support of the carrier layer with the print quality requirements.

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If carrier layer openings are machined with focused laser beam, then cutting accuracy is maintained, but web width reduction and production efficiency are limited

Engineering Contradiction:
Improvecarrier layer opening accuracyVSAvoidproduction simplicity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent changes the laser beam focus parameter to defocused state, which enables wider carrier layer openings to be machined with fewer pulses and less complexity. This parameter change simplifies the manufacturing process while maintaining adequate precision.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Instead of using a focused laser beam to cut precise narrow openings, the patent inverts the approach by using a defocused laser beam to create wider openings. This inverted method is simpler and more efficient for the specific application requirements.

Inventive Principle:
Principle #13The other way round (Inversion)

4Strength

If printing screens with screen fabric are used, then structural support is provided, but stencil durability and energy efficiency are reduced

Engineering Contradiction:
Improveprinting screen supportVSAvoidstencil durability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent extracts and removes the screen fabric from the printing screen structure. This elimination of the fabric component resolves the conflict between structural support and durability, as the carrier layer and structural layer provide sufficient support without the durability issues of screen fabric.

Inventive Principle:
Principle #2Taking out (Extraction)

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

Significantly reduces production time and cost of printing stencils while improving the uniformity and aspect ratio of contact fingers, enhancing energy efficiency and stencil durability.

Implementation Method 1

working out carrier layer openings in the carrier layer in the area of the printed image opening by means of laser cutting

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentEP2750891B1Method for producing a printing stencil for technical printing, and printing stencil for technical printing
Publication Date: 2019.03.20 CHRISTIAN KOENEN
  • EP2750891B1 patent drawingFigure 1~2B
  • EP2750891B1 patent drawingFigure 3A~3B
  • EP2750891B1 patent drawingFigure 4A~4B

AI summary

The present invention relates to a method for producing a printing stencil for technical printing, for applying a printed pattern to a substrate, and to a printing stencil. The method comprises supplying a carrier layer (21) for the printing stencil, supplying a structure layer (22) for the printing stencil, this layer being located beneath the carrier layer (21), making an elongate printed‑image opening (22a), corresponding to at least part of the printed pattern, in the structure layer (22), and making carrier‑layer openings (21a) in the carrier layer (21) in the region of the printed‑image opening (22a). The method is characterized in that, for making the carrier‑layer openings (21a), use is made of a laser device which is designed to emit a laser beam in laser pulses, and the task of making the carrier‑layer openings (21) comprises making a row of carrier‑layer openings (21a) extending in the longitudinal direction of the printed‑image opening, wherein, for making each carrier‑layer opening (21) in the row, a focussing means of the laser device is positioned at a position of the respective carrier‑layer opening (21), and the respective carrier‑layer opening (21) is made by means of one or more laser pulses at this position (P1), and the focussing means of the laser device, once a carrier‑layer opening has been made, between two successive laser pulses, is displaced relative to the carrier layer, and in the longitudinal direction of the elongate printed‑image opening (22a), from the position (P1) of the carrier‑layer opening (21a) which has been made to the position (P2) of the carrier‑layer opening which is subsequently to be made.