JP6021463B2 - Liquid discharge head and method of manufacturing liquid discharge head - Google Patents

Description

  The present invention relates to a liquid discharge head using a piezoelectric element and a method for manufacturing the liquid discharge head.

  2. Description of the Related Art A liquid discharge recording apparatus that discharges ink and records an image on a recording medium is generally equipped with a liquid discharge head that discharges ink. A mechanism using a pressure chamber whose volume can be contracted by a piezoelectric element is known as a mechanism of a liquid discharge head. A structure of such a liquid discharge head is disclosed in Patent Document 1.

  In the liquid discharge head disclosed in Patent Document 1, a PZT (lead zirconate titanate) plate in which a plurality of grooves are formed and a top plate that covers each groove are overlapped and bonded. Thereafter, the adhesive between the PZT plate and the top plate is sliced to a predetermined thickness. As a result, a PZT plate / top plate composite is formed. The plurality of grooves are divided into a groove serving as a pressure chamber and a groove serving as a dummy pressure chamber. A back plate having an opening communicating with the pressure chamber is bonded to the rear surface side of the composite. An electrode is formed on the inner surface of each groove. An electrode layer electrically connected to an electrode formed in a groove serving as a dummy pressure chamber is connected to the front surface of the composite. A common electrode pattern is formed on the side surface of the composite to electrically connect the electrode layer to the back plate.

Japanese Patent No. 40899957

  In the liquid discharge head disclosed in Patent Document 1, an orifice plate having an orifice hole communicating with a pressure chamber is joined to the front surface of the composite. Therefore, the electrode layer formed on the front surface of the composite is not exposed to the outside. On the other hand, the common electrode pattern formed on the side surface of the composite is exposed to the outside. Therefore, a process for covering the common electrode pattern with an insulating layer is required. This process may hinder productivity.

  An object of the present invention is to provide a liquid discharge head with high productivity and a method for manufacturing the liquid discharge head.

  In order to achieve the above object, a liquid discharge head according to the present invention includes an orifice plate in which discharge ports for discharging liquid are formed, and a pair of piezoelectric substrates each bonded to the orifice plate and overlapped in layers. The pair of piezoelectric substrates includes a plurality of grooves extending from a front surface facing the orifice plate toward a rear surface opposite to the front surface, and a part of the plurality of grooves. A plurality of grooves communicating with the discharge ports, electrodes formed on inner walls of the grooves, electrodes formed on the front surface, and formed on grooves excluding the partial grooves among the plurality of grooves; A common electrode connection layer electrically connected, and a common electrode lead-out wiring formed on at least one of the opposing surfaces and electrically connected to the common electrode connection layer.

  In order to achieve the above object, a method of manufacturing a liquid discharge head according to the present invention is a method of manufacturing a liquid discharge head using an orifice plate having a discharge port for discharging a liquid and a pair of piezoelectric substrates. Forming a plurality of grooves extending from one surface of each piezoelectric substrate toward a surface opposite to the one surface; forming electrodes on the inner wall of each groove; and forming a common electrode lead-out wiring on a surface orthogonal to the one surface Then, a step of laminating the other piezoelectric substrate on one piezoelectric substrate and the one surface of the pair of piezoelectric substrates laminated are formed as grooves except for some of the plurality of grooves. Forming a common electrode coupling layer electrically connected to an electrode; and joining the orifice plate to the one surface on which the common electrode coupling layer is formed so that the partial groove communicates with the discharge port. And a process of A.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the liquid discharge head with high productivity, and the manufacturing method of a liquid discharge head.

FIG. 3 is a perspective view of a liquid ejection head according to Embodiment 1. FIG. 2 is an exploded perspective view of the liquid discharge head shown in FIG. 1. It is the front view which looked at the piezoelectric material laminated body shown in FIG. 2 from the orifice plate side. It is a perspective view of a pair of piezoelectric substrate which comprises the piezoelectric material laminated body shown in FIG. It is a figure for demonstrating the electrode structure of the 1st piezoelectric substrate shown to Fig.4 (a). It is a figure for demonstrating the electrode structure of the 2nd piezoelectric substrate shown in FIG.4 (b). It is a figure for demonstrating the lamination process of a piezoelectric material laminated body. It is a figure for demonstrating the lamination process of a piezoelectric material laminated body. It is a whole perspective view of the laminated body in which the electrode connection layer was formed. It is the cross-sectional perspective view which cut and showed a part of laminated body shown in FIG. It is an enlarged view and sectional drawing of the laminated body shown in FIG. It is the perspective view which looked at the laminated body which has a common electrode connection layer from the rear surface side. It is the elements on larger scale for demonstrating the wiring structure shown in FIG. It is a perspective view for demonstrating the process of joining an aperture plate and an orifice plate to the piezoelectric material laminated body shown in FIG. 6 is a diagram showing a second piezoelectric substrate of Embodiment 2. FIG. 6 is a diagram illustrating a first piezoelectric substrate of Embodiment 3. FIG. FIG. 6 is a diagram illustrating a first piezoelectric substrate according to a fourth embodiment.

(Embodiment 1)
A first embodiment of the present invention will be described. FIG. 1 is a perspective view of the liquid discharge head of this embodiment. FIG. 2 is an exploded perspective view of the liquid discharge head shown in FIG.

  The liquid discharge head 101 of this embodiment has a piezoelectric material laminate 303. An orifice plate 304 having a discharge port 309 is bonded to the front surface of the piezoelectric material laminate 303. On the other hand, a diaphragm plate 302 (see FIG. 2) and a flexible cable 310 are bonded to the rear surface (ink supply port side) of the piezoelectric material laminate 303. A member having a common liquid chamber 301 and an ink supply port 305 is bonded to the diaphragm plate 302.

  FIG. 3 is a front view of the piezoelectric material laminate 303 as viewed from the orifice plate side. FIG. 3A is a front view showing the entire piezoelectric material laminate 303. FIG. 3B is an enlarged view of the region A shown in FIG. As shown in FIG. 3B, a plurality of pressure chambers 307 and a plurality of air chambers 308 are arranged in a matrix in the piezoelectric material laminate 303. The pressure chambers 307 and the air chambers 308 are alternately arranged in the row direction and the column direction. Electrodes are formed on the inner wall of the pressure chamber 307 and the inner wall of the air chamber 308.

  Hereinafter, a manufacturing method of the piezoelectric material laminate 303 will be described.

(Groove process)
The piezoelectric material laminate 303 is composed of a pair of piezoelectric substrates that are stacked in layers. FIG. 4 is a perspective view of a pair of piezoelectric substrates constituting the piezoelectric material laminate 303. FIG. 4A is a perspective view of the first piezoelectric substrate 501 which is one piezoelectric substrate. FIG. 4B is a perspective view of a second piezoelectric substrate 502 that is the other piezoelectric substrate. As the first piezoelectric substrate 501 and the second piezoelectric substrate 502, for example, PZT (lead zirconate titanate) substrates are used.

  As shown in FIG. 4A, the first piezoelectric substrate 501 is formed with a concave first groove 503 and a second groove 504 extending from the front surface toward the rear surface. Grinding using a superabrasive wheel is used as a method for forming each groove. The first groove 503 functions as the pressure chamber 307 described above, and the second groove 504 functions as the air chamber 308 described above.

  The second groove 504 is processed so as not to communicate with the common liquid chamber 301 (see FIG. 2). Specifically, the second groove 504 terminates on the way from one surface (front surface) of the first piezoelectric substrate 501 to the opposite surface (rear surface) of the one surface. This is because in order for the second groove 504 to function as the air chamber 308, it is necessary to separate the liquid from the common liquid chamber 301 so as not to flow into the second groove 504.

  In the second piezoelectric substrate 502, as shown in FIG. 4B, a third groove 507 is formed by the same method as the first groove 503 and the second groove 504. The third groove 507 functions as the air chamber 308 described above. Similarly to the second groove 504, the third groove 507 is processed so as not to communicate with the common liquid chamber 301.

(Electrode process)
FIG. 5 is a view for explaining the electrode structure of the first piezoelectric substrate 501. FIG. 5A is a top view. FIG. 5B is a front view seen from the orifice plate 304 side. FIG. 5C is a bottom view. In the first piezoelectric substrate 501, the first electrode 505 is formed in the first groove 503, and the second electrode 506 is formed in the second groove 504. At this time, the common electrode lead-out wiring 521 is simultaneously formed on the upper surface of the first piezoelectric substrate 501. On the upper surface of the first piezoelectric substrate 501, the common electrode lead-out wiring 521 extends from the edge on the front surface side to the edge on the rear surface side. As shown in FIG. 5C, a third electrode 508 is formed on the lower surface of the first piezoelectric substrate 501. The third electrode 508 functions as an electrode for driving the bottom wall of the first groove 503. Therefore, the third electrode 508 is formed at a position corresponding to the first groove 503.

  The first electrode 505, the second electrode 506, the third electrode 508, and the common electrode lead-out wiring 521 are patterned by a lift-off method using a photosensitive resist or laser removal. Specifically, Cr is formed as a base layer, and Au is formed as an electrode layer on Cr. Alternatively, Cr may be formed as an underlayer, and Pd may be formed on Cr and patterned. Furthermore, Ni plating may be performed using Pd as a seed layer, and Ni on the surface may be replaced with Au. In particular, the plating method has a thin film thickness at the time of lift-off, so that burrs are hardly left and patterning properties are improved. Furthermore, since Au is used only on the surface, the cost is low.

  FIG. 6 is a diagram for explaining the electrode structure of the second piezoelectric substrate 502. FIG. 6A is a top view. FIG. 6B is a front view seen from the orifice plate 304 side. FIG. 6C is a bottom view. A fourth electrode 509 is formed in the third groove 507 of the second piezoelectric substrate 502. The fourth electrode 509 can be formed by a method similar to that of the first electrode 505 to the third electrode 508 described above. A common electrode lead wiring 522 is formed on the upper surface of the second piezoelectric substrate 502. On the upper surface of the second piezoelectric substrate 502, the common electrode lead-out wiring 522 extends from the edge on the front surface side to the edge on the rear surface side. In the present embodiment, the common electrode lead-out wiring 522 is formed simultaneously with the fourth electrode 509. As shown in FIG. 6C, a fifth electrode 512 is formed on the lower surface of the second piezoelectric substrate 502. The fifth electrode 512 is formed at a position corresponding to the third groove 507. When the second piezoelectric substrate 502 is stacked on the first piezoelectric substrate 501, the fifth electrode 512 closes the upper opening of the first groove 503 formed in the first piezoelectric substrate 501.

  The common electrode lead-out wiring 521 and the common electrode lead-out wiring 522 are electrically connected later and play the same role. Therefore, a configuration in which only one of the common electrode lead-out wiring 521 and the common electrode lead-out wiring 522 may be formed. In this configuration, it is desirable to increase the width of the wiring in order to reduce the wiring resistance.

(Polarization process)
Next, each of the first piezoelectric substrate 501 and the second piezoelectric substrate 502 is subjected to polarization processing. The first piezoelectric substrate 501 polarizes the inner wall of the first groove 503 in three different directions. A high electric field is applied between the first electrode 505 with a positive potential and the second electrode 506 and the third electrode 508 with a ground potential. The polarization treatment is performed by applying a high electric field of about 1 to 2 kV / mm between the first electrode 505 and the second electrode 506 for a predetermined time while being heated to about 100 to 150 ° C. The polarization treatment is desirably performed in oil with high insulation properties such as silicone oil (dielectric breakdown voltage: 10 kV / mm or more). Silicone oil can be removed after polarization by a hydrocarbon solvent such as xylene, benzene or toluene, or a chlorinated hydrocarbon solvent such as methylene chloride or chlorobenzene.

  After polarization, an aging process is performed as necessary. The first piezoelectric substrate 501 that has been subjected to the polarization treatment is held for a certain period of time in a heated state, thereby stabilizing its piezoelectric characteristics. In the aging treatment, for example, the first piezoelectric substrate 501 subjected to the polarization treatment is left in an oven at 100 ° C. for 10 hours.

  The second piezoelectric substrate 502 is also polarized by the same method as the polarization process described above. In the second piezoelectric substrate 502, the fourth electrode 509 is set to the ground potential, and the fifth electrode 512 is set to the positive potential. Polarization is performed by applying a high electric field of about 1 to 2 kV / mm between the electrodes for a predetermined time.

(Lamination process)
Next, a lamination process will be described with reference to FIGS. As shown in FIG. 7A, the first piezoelectric substrate 501 is formed with a first groove 503 and a second groove 504 arranged on both sides of the first groove 503. The first groove 503 functions as a pressure chamber 307 communicating with the discharge port 309. The second groove 504 functions as the air chamber 308. A first electrode 505 (not shown in FIG. 7A) is formed on the inner wall of the first groove 503, and a second electrode 506 (not shown in FIG. 7A) is formed on the inner wall of the second groove 504. (Shown) is formed. A third electrode 508 (not shown in FIG. 7A) is formed on the back surface of the surface where the first groove 503 and the second groove 504 are formed.

  In the second piezoelectric substrate 502, a third groove 507 that functions as the air chamber 308 is formed at a position corresponding to the first groove 503 of the piezoelectric substrate 501. A fourth electrode 509 (not shown in FIG. 7A) is formed on the inner wall of the third groove 507. A fifth electrode 512 (not shown in FIG. 7A) is formed on the back surface (lower surface) of the surface (upper surface) where the third groove 507 is formed.

  As shown in FIG. 7B, the first piezoelectric substrate 501 is laminated and bonded to the second piezoelectric substrate 502. For the bonding, for example, an epoxy adhesive is used. At this time, it is necessary to appropriately control the amount of adhesive in order to prevent the grooves from being filled with adhesive. As a method for applying the adhesive, a thin uniform adhesive layer is formed on another flat substrate by spin coating or screen printing. By pressing and releasing the adhesive surface of the first piezoelectric substrate 501 or the second piezoelectric substrate 502 against this, a thin and uniform adhesive layer can be formed on the piezoelectric substrate. After applying the adhesive, positioning is performed with a minute gap between the first substrate 501 and the second substrate 502, and then pressure bonding is performed.

  The alignment at the time of stacking can be performed by abutting the end face of each piezoelectric substrate against the positioning pin, and in order to further improve the positioning accuracy, alignment by a camera may be performed. As a mark used for alignment by the camera, a chip edge, a groove, an alignment mark patterned at the time of electrode formation, or the like can be used.

  As shown in FIG. 7B, a laminate including the first piezoelectric substrate 501 and the second piezoelectric substrate 502 as one unit is overlapped and bonded in a plurality of layers as shown in FIG. 7C. .

  A substrate 510 is bonded to the lowermost layer of the laminate shown in FIG. 7C as shown in FIG. A substrate 511 is bonded to the uppermost layer of the stacked body as shown in FIG. A substrate 523 is bonded on the substrate 511 as shown in FIG. The substrate 510, the substrate 511, and the substrate 523 need not be piezoelectric substrates. In the case where heating is required at the time of bonding, it is desirable that the material of each substrate has the same thermal expansion coefficient as that of the first piezoelectric substrate 501 and the second piezoelectric substrate 502.

(Polishing process)
The front surface and the rear surface (both surfaces where the pressure chamber 307 is exposed) of the laminate shown in FIG. 8 are flattened by a polishing process. Abrasive grains are used for polishing. For the subsequent electrode formation step, the surface roughness is preferably about Ra 0.4 μm. In order to attach the orifice plate 304 and the rear diaphragm plate 302 with high accuracy, it is preferable that the flatness of each surface is within 10 μm and the parallelism between the end surfaces is within 30 μm.

(Common electrode connection layer formation process)
A process of forming the common electrode coupling layer 817 on the laminated body whose front and rear surfaces are polished will be described with reference to FIGS. 9, 10, and 11. FIG. 9 is an overall perspective view in which a common electrode layer 817 is formed on a laminated body whose front and rear surfaces are polished. 10 is a cross-sectional perspective view showing a part of the laminate shown in FIG. 11 is an enlarged view and a sectional view of the laminate shown in FIG. FIG. 11A is an enlarged view of the common electrode connection layer 817 shown in FIG. FIG. 11B is a cross-sectional view taken along the cutting line CC shown in FIG. FIG.11 (c) is sectional drawing along the cutting line DD shown to Fig.11 (a).

  The common electrode connection layer 817 is formed on the front surface 806 (see FIG. 10) of the stacked body. As shown in FIGS. 11A and 11B, the common electrode connection layer 817 connects the second electrode 506, the third electrode 508, and the fourth electrode 509 to form a common electrode. The common electrode connection layer 817 is electrically connected to the common electrode lead-out wiring 521 and the common electrode lead-out wiring 522 as shown in FIG. Thereby, the wiring electrically connected to each electrode made into the common electrode by the common electrode coupling layer 817 is drawn out to the rear surface 807 (squeezing plate pasting surface) of the laminate. The common electrode connection layer 817 is not electrically connected to the first electrode 505 and the fifth electrode 512. Specifically, the common electrode connection layer 817 is formed away from the first electrode 505 and the fifth electrode 512.

  A method for forming the common electrode connection layer 817 will be described below.

  Since the front surface 806 of the laminate has irregularities such as a pressure chamber 307 and an air chamber 308, it is difficult to form a uniform resist film by a method using a normal spin coater. Therefore, a film resist laminate is suitable. A negative type resist is used for the film.

  In the lift-off, a resist is formed by photolithography so that a resist is left in a portion where an electrode pattern is not desired to be left, and a metal layer serving as an electrode is formed on the entire surface including the resist pattern by sputtering or vapor deposition. Then, by removing the resist, the metal film formed on the resist is peeled off together with the resist, and a desired metal film pattern is finally obtained.

  The common electrode connection layer 817 is formed, for example, by depositing Cr as a base layer and depositing Au as an electrode layer on Cr. Alternatively, Cr may be deposited as an underlayer, and Pd may be deposited on Cr and patterned. Furthermore, Ni plating may be performed using Pd as a seed layer, and Ni on the surface may be replaced with Au. A sputtering method or a vapor deposition method can be adopted as the film forming method. In particular, the plating method has a thin film thickness at the lift-off, so that the patterning property is improved and Au is used only on the surface, so that the cost is low.

(Rear wiring and connection terminal formation process)
A process of forming a wiring pattern on the rear surface of the laminate having the common electrode connection layer 817 will be described with reference to FIGS. FIG. 12 is a perspective view of a laminated body having the common electrode coupling layer 817 as seen from the rear surface side. FIG. 13 is a partially enlarged view for explaining the wiring structure shown in FIG. FIG. 13A is a rear view. FIG. 13B is a cross-sectional view taken along a cutting line EE shown in FIG.

  As shown in FIG. 13A, individual electrode wirings 816 are formed on the rear surface of the multilayer body. The individual electrode wiring 816 is electrically connected to the first electrode 505 and the fifth electrode 512 (not shown in FIG. 13A). In addition to the individual electrode wiring 816, wiring 820 is formed on the rear surface of the stacked body (see FIG. 13A). The wiring 820 is electrically connected to the common electrode lead-out wirings 521 and 522 as shown in FIG.

  An individual electrode connection terminal 814 is formed on the upper side of the individual electrode wiring 816 as shown in FIG. The individual electrode connection terminal 814 is electrically connected to the individual electrode wiring 816. A common electrode connection terminal 821 is formed on the upper side of the wiring 820 as shown in FIG. The common electrode connection terminal 821 is electrically connected to the wiring 820. Thus, the piezoelectric material laminate 303 is completed.

  The above-described individual electrode wiring 816 is formed by, for example, forming Cr as a base layer and depositing Au as an electrode layer on Cr. Alternatively, Cr may be formed as an underlayer, Pd may be formed on Cr and patterned, and then Ni plating may be performed using Pd as a seed layer, and Ni on the surface may be replaced with Au. Good.

  As described above, the individual electrode connection terminal 814 and the common electrode connection terminal 821 can be formed by the same process because the common electrode lead-out is provided on the laminated surfaces (surfaces orthogonal to the front and rear surfaces and facing each other) of each piezoelectric substrate. This is because the wirings 520 and 521 are formed.

  FIG. 14 is a perspective view for explaining a process of joining the diaphragm plate 302 and the orifice plate 309 to the piezoelectric material laminate 303 shown in FIG.

(Drawing plate bonding process)
A diaphragm plate 302 is bonded to the rear surface of the piezoelectric material laminate 303. An aperture 809 is provided in the aperture plate 302 at a position corresponding to each pressure chamber 307. The opening 809 restricts the back flow of the ink so that the ink flow generated by driving is strongly generated on the ejection port 309 side. The opening 809 can be formed by etching a silicon substrate. The diameter of the opening 809 is smaller than the diameter of the opening end of the pressure chamber 307. For bonding, for example, an epoxy adhesive is used.

  The rear diaphragm plate 302 is bonded to the piezoelectric material laminate 303 so that the individual electrode connection terminal 814 and the common electrode connection terminal 821 are exposed.

(Orifice plate joining process)
An orifice plate 304 is joined to the front surface of the piezoelectric material laminate 303. The orifice plate 304 is a plate-like member in which a circular discharge port 309 is formed at a position corresponding to each pressure chamber 307 of the piezoelectric material laminate 303. An example of a method for producing the orifice plate 304 is nickel electroforming. The front surface of the orifice plate 304 (the back surface of the surface facing the piezoelectric material laminate 303) is subjected to ink repellent treatment. Examples of the ink repellent material include silane-based and fluorine-based materials. An ink repellent treatment is performed by coating these materials by vapor deposition or the like.

  The orifice plate 304 is bonded to the piezoelectric material laminate 303 using, for example, an adhesive. For the bonding, for example, an epoxy adhesive is used.

(Flexible cable wiring mounting process)
As shown in FIG. 14, the flexible cable 310 is crimped to the individual electrode connection terminal 814 and the common electrode connection terminal 821. The individual electrode connection terminal 814 and the common electrode connection terminal 821 are formed in a row on the same surface. Therefore, it can connect in a lump with one flexible cable. As a connection method, there is a connection method using an anisotropic conductive film (ACF). After crimping, the vicinity of the joint between each terminal and the flexible cable 310 is reinforced with an adhesive.

(Common liquid chamber bonding process)
Thereafter, a common liquid chamber 301 having an ink supply port 305 is prepared and joined to the rear diaphragm plate 302 as shown in FIGS. The common liquid chamber 301 is created, for example, by machining a SUS (Steel Use Stainless) substrate. The common liquid chamber 301 is joined to the aperture plate 302 using an adhesive.

  Finally, other necessary parts are further assembled to complete the liquid discharge head.

  In the liquid discharge head of the present embodiment described above, the common electrode lead-out wirings 521 and 522 are formed not on the side surface of the piezoelectric material laminate 303 but on the laminated surface of the first piezoelectric substrate 501 and the second piezoelectric substrate 502. Yes. Therefore, the common electrode lead lines 521 and 522 are not exposed to the outside. This eliminates the need to cover the common electrode lead-out wirings 521 and 522 with the insulating film. Therefore, productivity can be increased.

  Furthermore, in this embodiment, the common electrode lead-out wirings 521 and 522 are formed simultaneously with the electrodes formed on the inner walls of the grooves of each piezoelectric substrate. Therefore, the process of forming only the common electrode wirings 521 and 522 is not necessary. Therefore, productivity is further improved by shortening the manufacturing process.

  In the present embodiment, a configuration in which the pressure chambers 307 and the discharge ports 309 are arranged in 5 rows and 5 columns is described. However, in the present invention, the arrangement form of the discharge ports 309 and the arrangement form of the pressure chambers 307 (the number of grooves and the number of stacked piezoelectric substrates) are not particularly limited.

  In the present embodiment, a so-called Gould type liquid ejection head that deforms four walls constituting the pressure chamber 307 is described. However, the present invention can also be applied to a so-called shear mode type liquid discharge head that discharges by shear deformation of the side wall of the pressure chamber.

(Embodiment 2)
A second embodiment of the present invention will be described. Hereinafter, a description will be given focusing on differences from the first embodiment. FIG. 15 is a diagram illustrating a second piezoelectric substrate according to the second embodiment. FIG. 15A is a top view. FIG. 15B is a front view.

  In the second piezoelectric substrate 502 shown in FIG. 15, the common electrode lead-out wiring 522 is formed on the inner wall of the groove 530 (other groove). By forming the common electrode lead-out wiring 522 on the inner wall of the groove 530, in the process of connecting the common electrode connection layer 817 formed after the common electrode lead-out wiring 522 and each wiring, the throwing power of the metal film by sputtering or vapor deposition Will improve.

  In the present embodiment, the second piezoelectric substrate 502 has been described as an example, but the first piezoelectric substrate 501 may have a similar structure. That is, a groove in which the common electrode lead wiring 521 is formed may be formed in the first piezoelectric substrate 501.

(Embodiment 3)
Embodiment 3 of the present invention will be described. The following description will focus on the differences from the first and second embodiments. FIG. 16 is a diagram illustrating a first piezoelectric substrate according to the third embodiment. FIG. 16A is a top view. FIG. 16B is a front view.

  In the first piezoelectric substrate 501 of the present embodiment, the common electrode lead-out wiring 522 is formed in the groove 504n located on the outermost side among the plurality of grooves formed in the first piezoelectric substrate 501. The groove 504n extends from the front surface 806 to the rear surface 807 in the same manner as the first groove 503.

  According to the present embodiment, the formation area of the common electrode lead-out wiring 521 is reduced as compared with the second embodiment. Therefore, the liquid discharge head can be reduced in size.

(Embodiment 4)
Embodiment 4 of the present invention will be described. Hereinafter, a description will be given focusing on differences from Embodiments 1 to 3 described above. FIG. 17 is a diagram illustrating a first piezoelectric substrate according to the fourth embodiment. FIG. 17A is a top view. FIG. 17B is a front view. FIG. 17C is a bottom view.

  In the first piezoelectric substrate 501 of this embodiment, as shown in FIG. 17C, a common electrode 530 is formed on the back surface of the formation surface of the first groove 503 and the second groove 504. The common electrode 530 has a function similar to that of the third electrode 508 (see FIG. 5C) described in Embodiment 1, and has a shape in which a plurality of third electrodes 508 are integrated. One end of the common electrode 530 is electrically connected to the common electrode coupling layer 817 at the edge on the front surface 806 side. On the other hand, the other end of the common electrode 530 terminates in the middle without reaching the edge on the rear surface 807 side.

  A common electrode lead-out wiring 523 is electrically connected to the other end of the common electrode 530. The common electrode lead-out wiring 523 is formed outside the region D as shown in FIG. Region D corresponds to region W shown in FIG. A region W indicates an arrangement region in which the first grooves 503 are arranged on the upper surface of the first piezoelectric substrate 501. That is, in this embodiment, the common electrode lead-out wiring 523 is formed outside the region W. Therefore, it is possible to secure a sufficient area for forming the individual electrode wiring 816 (see FIG. 13A) formed on the rear surface 807 of each piezoelectric substrate.

501 First piezoelectric substrate 502 Second piezoelectric substrate 521 Common electrode lead-out wiring 817 Common electrode connection layer

Claims (5)

A liquid discharge head having an orifice plate in which a discharge port for discharging liquid is formed, and a pair of piezoelectric substrates bonded to the orifice plate and overlapped in layers,
The pair of piezoelectric substrates are a plurality of grooves extending from a front surface facing the orifice plate toward a rear surface opposite to the front surface, and some of the plurality of grooves communicate with the discharge port. A plurality of grooves, an electrode formed on an inner wall of each groove, and a common electrode formed on the front surface and electrically connected to an electrode formed on the groove excluding the part of the plurality of grooves. A liquid discharge head, comprising: a coupling layer; and a common electrode lead-out wiring formed on at least one of the surfaces facing each other and electrically connected to the common electrode coupling layer.   The liquid ejection head according to claim 1, wherein the pair of piezoelectric substrates further includes another groove in which the common electrode lead-out wiring is formed.   The liquid ejection head according to claim 1, wherein the common electrode lead-out wiring is formed in a groove formed on the outermost side among the plurality of grooves. In one piezoelectric substrate, it is arranged in a surface on which the part of the groove perpendicular to the front, and the common electrode connecting layer and electrically connected to the common electrode on the back surface of said surface, and pre-Symbol common electrode connection layer The electrically connected common electrode lead-out wiring is formed,
The liquid ejection head according to claim 1, wherein the common electrode lead-out wiring is formed outside an array region of the partial grooves.   5. The liquid ejection head according to claim 1, wherein a laminate including the pair of piezoelectric substrates as one unit overlaps with each other in a plurality of layers.

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