Liquid Ejection Head High-Density Orifice Substrate Segmentation
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Solution Overview
Problem
Existing liquid ejection heads face limitations in arranging ejection orifices at high density due to constraints in substrate usage and strict joining conditions, which affect production yield and resolution capabilities.
Innovation Solution
A liquid ejection head design featuring a substrate with a piezoelectric element, an ejection orifice forming member, and thin films that allow for efficient use of substrate space for wirings and high-density orifice arrangement, along with a method that includes forming communicating ports and sacrificial layers to facilitate precise etching and orifice formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If anisotropic etching is used to remove the sacrificial layer and form a space for displacing the piezoelectric element and vibrating plate, then the space is successfully formed, but the substrate region corresponding to the piezoelectric element is completely removed, preventing wiring arrangement and limiting ejection orifice density
Solution Approach 1:
The patent divides the substrate into multiple regions: a first region where the piezoelectric element is formed, a second region adjacent to it where wirings are arranged, and a third region where ejection orifices are formed. This segmentation allows the substrate to serve multiple functions simultaneously, enabling both the displacement space and wiring arrangement without conflict.
Solution Approach 2:
The patent extends the substrate usage into the planar dimension rather than only utilizing the vertical space. By arranging wirings in a second region adjacent to the piezoelectric element region on the substrate surface, the design充分利用s the substrate area, allowing both displacement space and wiring integration without requiring complete substrate removal.
2Stability of the object's composition
If physical connection by adhesive and electric connection by gold bump are simultaneously performed to stack and join two substrates, then substrate joining is achieved, but the joining conditions are strict and production yield may be reduced
Solution Approach 1:
The patent combines the adhesive layer and gold bump structures into a single integrated joining layer that performs both physical adhesion and electrical connection functions. This merging simplifies the joining process and reduces the number of separate operations required, thereby relaxing joining conditions and improving production yield.
Solution Approach 2:
The joining layer is designed to serve multiple functions simultaneously: it provides mechanical adhesion between substrates, establishes electrical connections, and maintains structural stability. This multi-functionality eliminates the need for separate adhesive and bump structures, simplifying the overall joining process.
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
Enables high-density arrangement of ejection orifices and reduces production yield loss by efficiently using substrate space and relaxing joining conditions, thereby enhancing the capability to record high-resolution images.
Implementation Method 1
By applying a voltage, the piezoelectric element is contracted in an in-plane direction, and accordingly the vibrating plate is deformed (bent and deformed) in an out-of-plane direction to generate a pressure in a pressure chamber.
Data Source
AI summary
A liquid ejection head includes a substrate, a piezoelectric element above the substrate, an orifice forming member above the substrate on the piezoelectric-element-provided-side, in which the orifice forming member has an ejection orifice for ejecting liquid and defines a pressure chamber between the orifice forming member and the substrate, and the pressure chamber communicates with the ejection orifice and includes the piezoelectric element therein, a first thin film provided between the substrate and piezoelectric element and defining a space between the first film and the substrate, and a second thin film on the piezoelectric element on the side opposite to the first film side and differing from the first film in rigidity. A communicating port is formed in the substrate in a region facing the space, communicates with the space through an opening having a smaller area than the area of the region, and is closed at an end.