Liquid Ejection Recording Head Lead Electrode Sealing Stability
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Solution Overview
Problem
In liquid ejection recording heads, the presence of dummy leads not connected to the recording element substrate can cause instability in the sealing agent, leading to exposure and depression issues during the curing process, affecting the reliability and stability of the electrode sealing.
Innovation Solution
The design includes lead electrodes connected to adjacent electrode pads with a wider bent part and a narrower end, ensuring a stable shape and uniform sealing agent application, while maintaining a high-density lead wire arrangement and preventing exposure of dummy leads by adjusting their length and positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If dummy leads are provided on the electric wiring substrate to prevent sealing agent sinking, then the shape of the electrode sealing agent becomes stable, but the device complexity increases due to additional leads and wiring
Solution Approach 1:
The patent extracts the dummy lead from the functional wiring structure and positions it specifically at the test electrode pad location. This separates the sealing stability function from the electrical connection function, allowing the dummy lead to serve its purpose of preventing sealing agent sinking without being integrated into the active signal transmission path, thereby reducing overall device complexity.
Solution Approach 2:
The dummy lead serves multiple purposes: it acts as a structural element to prevent sealing agent sinking during assembly, and it is positioned to correspond with the test electrode pad for potential testing functions. This multi-functionality reduces the need for separate structural supports and electrical test elements.
2Stability of the object's composition
If lead electrodes are made wide to prevent exposure during sealing, then the sealing agent shape becomes stable, but the lead wire arrangement density decreases
Solution Approach 1:
The patent applies local quality by making only the specific lead electrodes adjacent to unconnected electrode pads have increased width, while other lead electrodes maintain their original dimensions. This localized widening provides the necessary sealing stability where needed without compromising the overall lead wire arrangement density across the entire substrate.
Solution Approach 2:
The lead electrode structure is made asymmetric by creating different width dimensions for different lead electrodes. Specifically, lead electrodes adjacent to unconnected electrode pads have a first width greater than the second width of other lead electrodes, allowing optimized sealing performance at critical locations while maintaining compactness elsewhere.
3Stability of the object's composition
If dummy leads are positioned at test electrode pad locations, then the sealing agent obtains stable shape, but the manufacturing precision requirements increase for positioning
Solution Approach 1:
The dummy lead is pre-positioned on the electric wiring substrate at the location corresponding to the test electrode pad before the sealing process. This preliminary positioning ensures that the dummy lead is already in the correct location to prevent sealing agent sinking during assembly, eliminating the need for high-precision adjustments during the sealing operation itself.
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 configuration achieves a stable shape of the sealing agent, enhancing the reliability and preventing exposure of lead electrodes, thereby improving the overall performance and reliability of the liquid ejection recording head.
Implementation Method 1
a recording element substrate including an ejection energy generation element and a plurality of electrode pads, the ejection energy generation element being configured to generate ejection energy by which to eject a liquid
Implementation Method 2
The adhesive and the sealing agent are cured by applying heat thereto
Data Source
AI summary
A liquid ejection recording head includes a recording element substrate including an ejection energy generation element and a plurality of electrode pads, the ejection energy generation element being configured to generate ejection energy by which to eject a liquid, the liquid ejection recording head also includes an electric wiring substrate including a plurality of lead electrodes connected to corresponding electrode pads to apply an electric signal to the ejection energy generation element, wherein one or more of the plurality of electrode pads are not connected to any lead electrode, and each lead electrode connected to an electrode pad adjacent to any of the one or more of the plurality of electrode pads not connected to any lead electrode has a wide part whose width is greater than the width of the other lead electrodes.