ZrO2 Insulating Film Impurity Gradient for Liquid Ejecting Head Crack Resistance
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Solution Overview
Problem
Liquid ejecting heads with vibrating plates composed of ZrO2 and SiO2 insulating films experience cracking due to residual stress when actuated by piezoelectric elements, leading to instability and reduced performance.
Innovation Solution
A vibrating plate design with a SiO2 elastic film and a ZrO2 insulating film, where the ZrO2 film contains a first impurity element with a higher concentration at the interface than in the internal region, providing residual compressive stress and enhancing the plate's strength and adhesiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating film composed of ZrO2 and SiO2 is used in the vibrating plate, then the insulating performance is improved, but the vibrating plate may crack due to residual stress
Solution Approach 1:
The patent applies local quality by creating a non-uniform distribution of impurity elements within the ZrO2 insulating film. Specifically, the impurity concentration is higher at the interface region between the ZrO2 film and SiO2 elastic film, and lower in the internal region. This localized variation in impurity concentration creates corresponding local variations in residual stress, with compressive stress concentrated at the interface where it most effectively prevents crack initiation and propagation, thereby resolving the contradiction between maintaining insulating performance and preventing cracking.
Solution Approach 2:
The patent employs parameter changes by deliberately controlling and varying the impurity element concentration within the ZrO2 insulating film. By adjusting the impurity concentration distribution (higher at interface, lower internally), the residual stress state of the film is changed from uniform to non-uniform. This parameter modification allows the film to maintain its insulating properties while developing a favorable stress profile that enhances crack resistance, thus resolving the technical contradiction.
2Ease of operation
If external force is applied to the vibrating plate during piezoelectric actuation, then the liquid ejection function is achieved, but the vibrating plate may crack under stress
Solution Approach 1:
The patent applies preliminary anti-action by pre-introducing compressive residual stress into the ZrO2 insulating film through controlled impurity distribution before the piezoelectric actuation occurs. This pre-existing compressive stress counteracts the tensile stresses that develop during piezoelectric actuation when external force is applied to the vibrating plate. By having this opposing stress state in place beforehand, the plate can withstand the actuation forces without cracking, thus resolving the contradiction between achieving ejection functionality and maintaining structural integrity.
3Ease of manufacture
If the ZrO2 film has uniform impurity distribution, then the manufacturing process is simpler, but the stress distribution is unfavorable and cracking occurs
Solution Approach 1:
The patent applies local quality by creating a non-uniform distribution of impurity elements within the ZrO2 insulating film. Specifically, the impurity concentration is higher at the interface region between the ZrO2 film and SiO2 elastic film, and lower in the internal region. This localized variation in impurity concentration creates corresponding local variations in residual stress, with compressive stress concentrated at the interface where it most effectively prevents crack initiation and propagation, thereby resolving the contradiction between maintaining insulating performance and preventing cracking.
Solution Approach 2:
The patent employs parameter changes by deliberately controlling and varying the impurity element concentration within the ZrO2 insulating film. By adjusting the impurity concentration distribution (higher at interface, lower internally), the residual stress state of the film is changed from uniform to non-uniform. This parameter modification allows the film to maintain its insulating properties while developing a favorable stress profile that enhances crack resistance, thus resolving the technical contradiction.
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 cracking and improves the strength and adhesiveness of the vibrating plate, ensuring stable operation and enhanced performance of the liquid ejecting head.
Implementation Method 1
a piezoelectric element and a vibrating plate configured to vibrate in response to actuation of the piezoelectric element
Implementation Method 2
The insulating film may have residual stress such as tensile stress. Consequently, when an external force is applied to the vibrating plate in response to actuation of the piezoelectric element, the vibrating plate may crack.
Data Source
AI summary
A liquid ejecting head includes a piezoelectric element and a vibrating plate configured to vibrate in response to actuation of the piezoelectric element, the vibrating plate including a first layer that contains SiO2 and a second layer that contains ZrO2 and that is stacked on the first layer. The second layer contains a first impurity element different from Zr, and the concentration of the first impurity element at an interface in contact with the first layer in the second layer is higher than the concentration of the first impurity element in an internal region that is included in the second layer and that is contiguous from the interface to the surface of the second layer.