JPH066374B2 - Multilayer piezoelectric displacement element - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated piezoelectric displacement element utilizing a piezoelectric longitudinal effect, and more particularly to an impulse jet type piezoelectric displacement element utilizing a minute volume change in an inkjet printer head.

Conventionally, in an inkjet printer of the impulse jet system, as a method of applying pulse pressure to ink to eject ink droplets from minute nozzles, it is common to use a piezoelectric displacement element in which the front and back surfaces of a piezoelectric ceramic thin plate are metallized. there were.

The piezoelectric displacement element is usually manufactured by making a thin plate having a thickness of 0.2 to 0.3 mm from a piezoelectric ceramics sintered block by machining, and metallizing the front and back surfaces thereof by plating, sputtering, vapor deposition, or the like. The thickness is 0.2 to 0.3
Impulse drive voltage is 200 to 300V due to the large thickness of mm
There was a drawback called necessary. FIG. 1 shows the structure of a conventional piezoelectric displacement element.

The present invention has been made to solve the drawback that the driving voltage is required to be 200 to 300V, and provides a laminated piezoelectric displacement element having an internal electrode having the same effect as a conventional one by driving a low voltage of several 10V. The purpose is to do.

The present invention uses a ceramic thin plate having a plurality of opposed internal electrode layers, and forms opposed surface electrodes connected to the internal electrodes on the front and back surfaces of the plate and connected to the internal electrodes in order to facilitate electrical connection. Mechanically chamfer each part of the end face on the side to form obtuse corners, then metallize the front and back surfaces by sputtering, vapor deposition, plating, etc., and then to the opposite side of the front and back electrodes connected by the chamfered parts. Electrodes are stripped off in the vicinity of the corners to form a laminated piezoelectric displacement element.

The manufacturing process of the present invention will be described in detail with reference to FIG.

FIG. 2A shows a piezoelectric ceramic 21 in which two layers of internal electrodes 22 are laminated. The 23 part indicated by a broken line in the figure indicates a part which is mechanically chamfered.

Reference numeral 24 in FIG. 2 (b) is a view showing a portion where the front and back surfaces are metallized by means such as sputtering or vapor deposition. At this time, the side surface portion is also metalized at the same time, which facilitates connection with the metallized portion of the internal electrode. Also, chamfering is performed to electrically connect the electrodes between the surface and the internal electrodes.

Reference numeral 25 in FIG. 2 (c) shows a view in which the metallized portion on the opposite side of the chamfered portion is removed in a strip shape. By this method, the front and back electrodes and the internal electrodes can be connected so as to form a counter electrode for each layer.

Hereinafter, the present invention will be described in detail with reference to Examples. As the piezoelectric ceramics for the actuator, titanate-lead zirconate composite perovskite ceramics are used,
A 60-micron-thick green sheet is coated with silver-
A laminated piezoelectric ceramic thin plate having four layers of internal electrodes of palladium is prepared. (Two layers in Fig. 2) The outer dimensions at this time are 1.4 mm x 18 mm x 0.25 mm (thickness).

Next, in order to improve the reliability of the device, the connection between the internal electrode and the external electrode is made tight, and the external electrode part angle is made obtuse in order to prevent the electrode breakage of the external electrode. The corner portion 23 of FIG. 2 (a) surrounded by a broken line was chamfered by grinding, and then gold was metallized on the front and back surfaces by sputtering.

After that, the chamfered portion 25 on the opposite side of the chamfered portion was stripped to a width of 3 mm to remove gold by sandblasting, and an electric insulating layer was provided to form an electrode.

Tables 1 and 3 show the relationship between the driving voltage of the laminated piezoelectric displacement element manufactured in this process and the amount of strain in the 0.25 mm direction (thickness direction).

For comparison, Table 1 shows the piezoelectric displacement of a piezoelectric element having a conventionally used structure.

From Table 1 and FIG. 3, obviously, according to the manufacturing method of the present invention, the driving voltage for obtaining the same strain amount is 1/100 of that of the conventional piezoelectric element.
It can be seen that the voltage is reduced to 5.

As described in detail above, according to the present invention, in the inkjet printer of impulse type, the driving voltage applied to the piezoelectric element for applying the pulse pressure to the ink can be reduced to 1/5. It has become possible to provide a method of manufacturing a laminated piezoelectric displacement element in which pulse pressure is applied to the ink.

[Brief description of drawings]

FIG. 1 is a diagram showing a conventionally used piezoelectric element structure.
Reference numeral 11 is a piezoelectric ceramic, and 12 is a metallized front and back electrodes. FIG. 2 shows a manufacturing process of the laminated piezoelectric displacement element according to the present invention. In FIG. 2 (a), 21 is a piezoelectric ceramic, 22 is an internal electrode, and 23 is a chamfer. Second
Reference numeral 24 in FIG. 2 (b) indicates a metallized portion on the front and back surfaces. Second
In FIG. (C), reference numeral 25 is a view showing a portion where the electrodes opposite to the front and back surface electrodes connected to the chamfered portions are stripped off. FIG. 3 is a comparative example of a laminated piezoelectric displacement element obtained by the manufacturing method of the present invention and a conventional element, showing a relational characteristic between voltage and strain amount, and A is a characteristic of the element by the manufacturing method of the present invention. And B is the characteristic of the device having the conventional structure. 11, 21 ... Piezoelectric ceramics. 12, 24 ... Metallized electrode film. 22… Internal electrodes. 23 ... Chamfer. 25 ... Removal part of electrode film. A: Characteristics of the device produced by the manufacturing method of the present invention. B: Characteristics of the device having the conventional structure.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location H01L 41/09 9274-4M H01L 41/08 M

Claims (1)

[Claims] 1. A piezoelectric displacement element for applying pulsed pressure to ink used in an ink jet printer, wherein the piezoelectric displacement element is a laminated type having a plurality of opposing internal electrode layers,
On the front and back surfaces of the ceramic thin plate, opposite surface electrodes that are connected to the internal electrodes are formed.The corners of the end faces that are connected to the internal electrodes are mechanically chamfered, and the front and back surfaces are formed by sputtering, vapor deposition, plating, etc. A laminated piezoelectric displacement element characterized in that a surface electrode is formed by metallizing and thereafter removing the electrode in a strip shape in the vicinity of the opposite corner on the chamfered electrode.