Inkjet Printing Head Cooling Member for Substrate Thermal Expansion
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Solution Overview
Problem
Inkjet printing for display device manufacturing faces errors due to thermal expansion of substrates, causing liquid discharge deviations from target positions, which existing methods fail to adequately address.
Innovation Solution
An inkjet printing apparatus with a head module and a cooling member, where the cooling member is strategically positioned to compensate for substrate temperature and thermal expansion, controlled by a module that adjusts its temperature and separation distance based on measured expansion using fiducial marks and a camera module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the substrate temperature is not compensated, then the manufacturing process is simple, but the liquid discharge position deviates from the target position due to thermal expansion
Solution Approach 1:
The cooling member is positioned upstream of the head nozzles in the substrate moving direction to preemptively cool the substrate before it reaches the printing zone. This preliminary cooling action prevents thermal expansion from occurring in the first place, thereby maintaining liquid discharge position accuracy without requiring complex real-time correction mechanisms
Solution Approach 2:
The cooling member acts as an intermediary element between the substrate and the head nozzles, absorbing excess heat from the substrate before it reaches the printing area. This mediator approach allows the system to maintain precision by introducing a thermal management component rather than directly modifying the substrate or nozzle system
2Manufacturing precision
If a cooling member is added to compensate for substrate temperature, then the liquid discharge position accuracy improves, but the device complexity increases
Solution Approach 1:
The cooling member is integrated into the head module assembly, merging the cooling function with the existing printing mechanism. This consolidation allows the system to gain temperature compensation capability while minimizing the increase in overall device complexity by sharing structural and control resources
Solution Approach 2:
The head module is designed to perform multiple functions: both liquid discharge (printing) and temperature compensation (cooling). By making the head module universal, the system avoids adding a completely separate cooling system, thereby improving precision while limiting the increase in device complexity
3Manufacturing precision
If the cooling member is positioned close to the substrate, then the temperature compensation efficiency increases, but the risk of liquid discharge errors increases due to thermal interference
Solution Approach 1:
The cooling member is positioned to cool only the upstream portion of the substrate that has not yet reached the printing zone. This localized cooling approach allows efficient temperature compensation in the non-printing area while avoiding thermal interference with the liquid discharge process in the printing area, thereby maintaining positioning reliability
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
Effectively maintains substrate temperature stability, preventing thermal expansion-induced errors in liquid discharge, ensuring precise positioning during the inkjet printing process.
Implementation Method 1
a cooling member spaced apart from the head nozzles in the second direction and configured to compensate for a temperature of the substrate
Implementation Method 2
a position where the liquid is actually discharged to the substrate may deviate from a target position due to various reasons (e.g., thermal expansion of the substrate)
Data Source
AI summary
An inkjet printing apparatus includes: a head module including a plurality of head nozzles and at least one cooling member, where the plurality of head nozzles are arranged in a row along a first direction and configured to discharge a liquid body on a substrate which moves along a second direction crossing the first direction, and the cooling member is spaced apart from the plurality of head nozzles in the second direction and configured to compensate for a temperature of the substrate; and a control module which provides a control signal for controlling the cooling member to the head module.