Flow Path Structure for Laser Welding Liquid Ejecting Heads
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Solution Overview
Problem
Existing liquid ejecting head technologies face issues with welding unevenness and stagnation of liquid at branch points due to inadequate laser welding techniques, leading to compromised air tightness and bubble discharge performance.
Innovation Solution
A flow path structure is developed using a light absorbing member and a light transmitting member, where the flow path pipe protruding from the front surface is included within the region of the first flow path in a plan view, preventing welding surface overlap and incorporating tapered portions to enhance liquid flow and reduce stagnation, thereby improving air tightness and bubble discharge performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser welding is performed on a substrate with a protruding flow path pipe, then the flow path structure is formed, but welding unevenness occurs due to laser light attenuation at the thicker protruding part
Solution Approach 1:
The patent changes the spatial arrangement by positioning the flow path pipe in a region that does not overlap with the welding surface when viewed in plan view. This dimensional repositioning allows the laser beam to uniformly illuminate the welding area without being attenuated by the protruding pipe structure, thereby achieving uniform welding while maintaining the complex flow path pipe configuration.
2Adaptability or versatility
If the flow path pipe protrudes from the substrate to form another flow path, then flow path connectivity is achieved, but the protruding part increases thickness and causes laser light attenuation
Solution Approach 1:
The patent resolves the conflict between flow path connectivity and laser energy transmission by positioning the flow path pipe in a different spatial zone. The pipe protrudes from the substrate to establish connectivity, yet is arranged such that its projection does not overlap with the welding surface in plan view, allowing laser light to pass through without significant attenuation.
3Manufacturing precision
If laser light is radiated from the flat plane side to avoid attenuation, then welding uniformity is improved, but the structure becomes less adaptable to complex flow path configurations
Solution Approach 1:
The patent achieves both welding uniformity and structural adaptability by utilizing the vertical dimension. The flow path pipe protrudes from the substrate surface, and the welding surface is positioned on the opposite side. This three-dimensional arrangement allows laser light to be radiated from the flat plane side for uniform welding while the protruding pipe maintains complex flow path connectivity, satisfying both requirements simultaneously.
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 solution effectively reduces welding unevenness, enhances air tightness, and improves bubble discharge performance by ensuring proper liquid flow and reducing stagnation at branch points within the liquid ejecting head.
Implementation Method 1
a light absorbing member having absorbing properties with respect to laser light
Implementation Method 2
a light transmitting member which is joined to the light absorbing member and has transmitting properties with respect to the laser light
Implementation Method 3
by welding the transparent member and the absorption member to each other by irradiating the contact portion with a laser beam
Implementation Method 4
heat energy of the laser light increases in the end portion region with the thickness of the end portion region thinner than that of other parts
Data Source
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AI summary
A flow path structure which forms a flow path of liquid, includes: a light absorbing member (first substrate) having absorbing properties with respect to laser light; a light transmitting member (second substrate) which is joined to the light absorbing member and has transmitting properties with respect to the laser light; a first flow path (flow path) which is surrounded by a welding surface on which the light absorbing member and the light transmitting member are welded; and a second flow path which is formed in a flow path pipe (flow path pipe) which protrudes from a front surface opposite to the welding surface in the light transmitting member, and communicates with the first flow path, in which the flow path pipe is included in a region of the first flow path in a plan view from a direction orthogonal to the welding surface.