Liquid Ejection Head Wiring Support for Reliable Wire Bonding
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Solution Overview
Problem
Existing liquid ejection heads face reliability issues in the electric connection between the recording element substrate and the electric wiring substrate due to unstable support during wire bonding, which can lead to defects and increased costs.
Innovation Solution
The electric wiring substrate is supported by the recording element substrate itself during wire bonding, eliminating the need for additional jigs and ensuring stable connection through the use of a sealant to protect the electric connection portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If wire bonding is performed without additional support members, then device complexity is reduced, but manufacturing precision deteriorates due to unstable support of the electric wiring substrate
Solution Approach 1:
The electric wiring substrate is integrated with the recording element substrate by making the end portion of the electric wiring substrate stand on the recording element substrate. This merging of support functions into the recording element substrate eliminates the need for separate support members, reducing device complexity while maintaining manufacturing precision during wire bonding.
Solution Approach 2:
The recording element substrate acts as an intermediary support structure for the electric wiring substrate during wire bonding. By positioning the end portion of the electric wiring substrate to stand on the recording element substrate, it provides stable support without requiring additional support members, thus resolving the contradiction between simplicity and precision.
2Manufacturing precision
If additional support members are used during wire bonding, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The support function is merged into the recording element substrate itself, which already exists in the device structure. The end portion of the electric wiring substrate stands on the recording element substrate, providing stable support during wire bonding without adding separate support members, thus improving manufacturing precision while avoiding increased device complexity.
3Ease of manufacture
If the electric wiring substrate is not supported during wire bonding, then ease of manufacture is improved, but reliability deteriorates due to unstable support
Solution Approach 1:
The recording element substrate serves as an intermediary support structure during wire bonding. The end portion of the electric wiring substrate is positioned to stand on the recording element substrate, providing the necessary stability for reliable wire bonding without complicating the manufacturing process, thus maintaining ease of manufacture while improving reliability.
4Reliability
If the end portion of the electric wiring substrate is separated from the electrode terminal, then reliability is improved, but length of connection member increases
Solution Approach 1:
The separation between the end portion of the electric wiring substrate and the electrode terminal creates a localized support structure where the end portion stands on the recording element substrate. This local separation improves reliability by providing stable support during wire bonding while minimizing the overall increase in connection member length, as the separation is confined to a specific region rather than extending the entire connection path.
Data Source
AI summary
A liquid ejection head includes a recording element substrate and an electric wiring substrate. The recording element substrate includes an ejection port configured to eject liquid, an energy generating element configured to generate energy for ejecting the liquid from the ejection port, and an electrode terminal that is electrically connected to the energy generating element. The electric wiring substrate is electrically connected to the electrode terminal by using wire bonding or the like. The electrode terminal is disposed on a connection surface of the recording element substrate, and a connection region in which electric connection to the electrode terminal is established is arranged at an end portion of the electric wiring substrate. The end portion of the electric wiring substrate is disposed above the surface of the recording element substrate on the connection surface side and is separated from the electrode terminal.