Solar Cell Screen Printing Head Spacing for Faster Precision Printing
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Solution Overview
Problem
There is a need for improved methods and apparatuses for screen printing on substrates used for solar cell manufacturing, specifically to address increasing demands for faster cycle times, higher precision, and better pattern quality.
Innovation Solution
The method involves using a print head and a material processing head, each driven by separate actuators, to perform printing and material processing strokes in a controlled sequence. The print head moves away from the material processing head during a distance increasing phase to enhance separation and prevent material accumulation, allowing for a more uniform layer preparation on the screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the print head and material processing head are positioned close together to save space and maintain compact apparatus design, then device complexity is reduced, but material accumulation occurs on the screen between the heads, degrading printing quality
Solution Approach 1:
The patent implements dynamic positioning where the print head and material processing head can independently adjust their positions along the screen. The control system varies the separation distance between heads based on process requirements, allowing the apparatus to transition between compact configurations (for space efficiency) and extended configurations (to prevent material accumulation). This dynamic adjustment resolves the contradiction by making the spatial relationship adaptive rather than fixed.
2Productivity
If the material processing head follows closely behind the print head to reduce cycle time, then productivity is improved, but material accumulation occurs on the screen, harming printing quality
Solution Approach 1:
The control system dynamically adjusts the timing and position of the material processing head relative to the print head based on real-time process parameters. During high-speed printing operations, the system can increase the separation distance or delay the material processing head to prevent accumulation. During normal operations, the heads can operate in closer sequence to minimize cycle time. This dynamic coordination allows the system to optimize both productivity and printing quality under different operating conditions.
Solution Approach 2:
The patent incorporates feedback mechanisms that monitor the printing process parameters including material flow rate, print head speed, and screen coating uniformity. This feedback information is used by the control system to adjust the timing and positioning of the material processing head, ensuring optimal separation distance is maintained to prevent material accumulation while minimizing cycle time. The feedback loop enables continuous optimization of the coordination between heads.
3Productivity
If the print head moves at high speed to increase productivity, then output is improved, but precision of the printing process deteriorates
Solution Approach 1:
The patent implements dynamic control of the print head speed and positioning system that can adjust velocity profiles during the printing stroke. The system maintains higher average speeds for productivity while using controlled acceleration and deceleration phases to ensure precision at critical moments. The independent actuation of the print head and material processing head allows for optimized speed coordination, where the material processing head can be positioned to compensate for any precision variations caused by high-speed printing.
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 enhances the quality of the printed layer on the substrate by maintaining a flat screen during material processing, reducing material accumulation, and allowing for faster cycle times without compromising precision.
Implementation Method 1
a squeegee may exert a pressure on a screen to urge deposition material through the screen so that the deposition material is deposited, i.e. printed, on the substrate below the screen
Data Source
AI summary
A method of performing screen printing on a substrate used for the manufacture of a solar cell is provided. The method includes moving a print head over a screen by a first drive actuator to perform a printing stroke in a first direction. The method includes moving a material processing head in the first direction by a second drive actuator to perform a material processing stroke behind the print head. The print head is moved away from the material processing head by the first drive actuator during a distance increasing phase of the printing stroke to increase a separation distance between the print head and the material processing head.