Piezoelectric device, liquid discharging head, and liquid discharging apparatus

Abstract

According to an aspect of the invention, the generation of cracks can be inhibited and the displacement efficiency can be improved. A piezoelectric device including a pressure chamber, a piezoelectricelement, and a diaphragm disposed between the pressure chamber and the piezoelectric element. The diaphragm has a crystal plane {100} of a single crystal silicon base. The piezoelectric element is disposed on the diaphragm so as to overlap an inner periphery of the pressure chamber in plan view, and has an inner edge on a center side of the pressure chamber with the inner periphery of the pressure chamber being sandwiched within the piezoelectric element in plan view. A shape of the inner edge of the piezoelectric element is such that in the smallest first rectangle, which includes the inneredge in plan view, the inner edge is on the inside of each of sides at a middle portion of each of the sides of the first rectangle. A shape of the inner periphery of the pressure chamber is such thatin the smallest second rectangle, which includes the inner periphery in plan view, the inner periphery is on the inside of each of sides at a middle portion of each of the sides of the second rectangle. A direction of one side out of the first rectangle and the second rectangle lies along a crystal orientation <010> in the crystal plane.

Description

technical field [0001] The present invention relates to a technology for generating pressure fluctuations by piezoelectric devices. Background technique [0002] Conventionally, there has been proposed a liquid ejection head in which liquid such as ink supplied to the pressure chamber is ejected from nozzles by varying the pressure of the pressure chamber using a piezoelectric device. For example, Patent Document 1 discloses that a vibrating plate (diaphragm) having a wall surface (upper surface) constituting the pressure chamber (increasing chamber) and a piezoelectric device vibrating the vibrating plate are provided for each pressure chamber. Components of piezoelectric device technology. The piezoelectric element is arranged on the peripheral portion of the circular pressure chamber, and by using the piezoelectric element, the vibration region overlapping with the pressure chamber in plan view in the vibration plate made of a single-layer silicon base material is reduce...

AI Technical Summary

Problems solved by technology

[0003] However, since the vibration plate of Patent Document 1 is composed of a single-layer silicon substrate, depending on the crystal plane of the silicon substrate used, the Young's modulus may vary depending on the direction within the crystal plane.

When the vibrating plate is formed of such a silicon base material, for example, since the crystal orientation with a large Young's modulus is less likely to warp than the crystal orientation with a small Young's modulus, it may hinder the overall Displacement of the vibrating plate

On the other hand, since the vibrating plate tends to bend in the crystal orientation with a small Young's modulus, cracks (cracks) tend to occur on the vibrating plate or the piezoelectric element when it is flexed excessively

However, since the crystal orientation is not taken into consideration in the shape of the pressure chamber or the piezoelectric element in Patent Document 1, if there is an orientation with a different Young's modulus around the vibration plate, it may hinder the vibration of the vibration plate as a whole. displacement, or prone to cracks

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