Inkjet Nozzle Plate Geometry for Stable Quadrangular Discharge Outlets
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Solution Overview
Problem
Existing nozzle plate manufacturing methods for inkjet printing in printed electronics result in discharge outlets with irregular shapes and unstable opening areas, leading to ink mists and satellites, which hinder high-quality printing, especially when high resolution is required for electronic circuits.
Innovation Solution
A method involving a photolithography process to form precise grooves on substrates, followed by bonding and cutting to create nozzle plates with straight nozzle holes and quadrangular discharge outlets, ensuring consistent opening shapes and reduced variations, using chemically and physically durable materials like SiO2 glass for the nozzle plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a laser beam is continuously irradiated on the surface of the substrate to form nozzle holes, then the temperature of the substrate near the surface becomes higher, but this creates a temperature distribution in the thickness direction causing the opening area of the discharge outlet to be larger than the opening area of the nozzle hole at the rear face
Solution Approach 1:
The patent applies periodic action by using pulsed laser irradiation instead of continuous laser beam. The laser is irradiated in pulses with specific intervals, allowing heat to dissipate between pulses and preventing excessive temperature accumulation. This resolves the temperature distribution issue while still achieving effective nozzle hole formation through repeated thermal cycles.
Solution Approach 2:
The patent uses excessive action by irradiating the laser beam multiple times on the same location. Each pulse contributes to the cumulative heating effect needed to create the nozzle hole, and the repeated irradiation ensures complete penetration and proper shape formation while controlling the overall temperature through pulse intervals.
2Productivity
If the pitch of discharge outlets is reduced to increase the number of nozzle holes, then productivity increases, but residual heat from preceding discharge outlets causes temperature variations affecting the shape of present discharge outlets
Solution Approach 1:
The pulsed laser irradiation method allows sufficient cooling time between pulses, even when processing multiple discharge outlets in close proximity. This periodic action prevents residual heat from affecting adjacent or subsequent discharge outlet formations, maintaining shape uniformity across all nozzles regardless of pitch density.
Solution Approach 2:
The patent rushes through the heating process by using short-duration laser pulses that deliver the necessary energy quickly before significant heat diffusion occurs. This allows rapid sequential processing of multiple discharge outlets without allowing heat to spread and distort the shapes of newly formed nozzles.
3Ease of manufacture
If a laser beam is used to form nozzle holes, then manufacturing is simplified, but the opening shape of discharge outlets is limited to circular or oval shapes which cause ink mists or satellites
Solution Approach 1:
The patent applies preliminary action by forming grooves on the substrate surface before laser irradiation. These pre-formed grooves serve as guides that constrain the laser heating to specific linear paths, enabling the creation of straight-sided discharge outlets with controlled angles. This preliminary structural preparation allows the laser to simply melt and remove material along the predetermined groove paths, achieving complex shapes that would otherwise require complex laser scanning patterns.
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
The method enables high-quality printing with reduced ink mists and satellites, allowing for precise control of discharge outlet dimensions and uniformity, accommodating various ink properties, and increasing productivity by maintaining standard deviations within ±3% for structural parameters.
Implementation Method 1
A method involving a photolithography process to form precise grooves on substrates
Implementation Method 2
irradiating a laser beam on the surface of a substrate that is to become a nozzle plate in its thickness direction. By irradiating the laser beam in the thickness direction of the substrate, portions of the substrate irradiated by the laser beam are melted
Data Source
Figure 1A~1D
Figure 2A~2B
Figure 3~4
AI summary
A nozzle plate having a nozzle hole that penetrates through the nozzle plate in a thickness direction is disclosed. The nozzle plate includes a discharge outlet that is formed at the nozzle hole, and provided curvatures of four corner portions of an opening shape of the discharge outlet are denoted as R1, R2, R3, and R4, the opening shape of the discharge outlet is configured to approximate the equation R1=R2≥R3=R4≈0.