JP2008229985A - Liquid ejection head and liquid ejection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid ejection head which can prevent water from flowing along a side surface of a lead electrode into a gap between the electrodes of piezoelectric elements, and to provide a liquid ejection device. <P>SOLUTION: The liquid ejection head includes: a channel forming substrate 10 having a plurality of pressure generating chambers communicating with nozzle openings for ejecting a liquid, respectively; the piezoelectric elements arranged on one side of the channel forming substrate, corresponding to the pressure generating chambers, respectively: the plurality of lead electrodes (individual lead electrodes 90) drawn from the piezoelectric elements, respectively; and a protective substrate having a piezoelectric element holding portion for protecting the piezoelectric elements, and connected to the surface of the channel forming substrate, which faces the piezoelectric elements, by an adhesive. Herein a contact portion 37 connected onto the lead electrodes on the protective substrate has recessed storage portions 371 in regions that are each opposed to a location between the lead electrodes, for storing the adhesive, and the adhesive fills recesses at both lateral edges of each lead electrode. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid ejecting head and a liquid ejecting apparatus, and in particular, a part of a pressure generating chamber communicating with a nozzle opening for ejecting ink droplets is configured by a vibration plate, and a piezoelectric element is formed on the surface of the vibration plate. The present invention relates to an ink jet recording head and an ink jet recording apparatus that eject ink droplets by displacement of a piezoelectric element.

  A part of the pressure generation chamber communicating with the nozzle opening for discharging ink droplets is constituted by a vibration plate, and the vibration plate is deformed by a piezoelectric element to pressurize the ink in the pressure generation chamber to discharge ink droplets from the nozzle opening. Two types of ink jet recording heads have been put into practical use: those using a longitudinal vibration mode piezoelectric actuator that extends and contracts in the axial direction of the piezoelectric element, and those using a flexural vibration mode piezoelectric actuator.

  As an example of using an actuator in a flexural vibration mode, for example, a uniform piezoelectric material layer is formed over the entire surface of the diaphragm by a film forming technique, and this piezoelectric material layer is formed into a pressure generating chamber by a lithography method. There is one in which piezoelectric elements are formed so as to be separated into corresponding shapes and independent for each pressure generating chamber.

  In addition, the piezoelectric element used for this flexural vibration mode actuator includes a lower electrode that is a common electrode, a piezoelectric layer formed on the lower electrode, and an upper electrode that is an individual electrode formed on the piezoelectric layer. It consists of and.

  In such a conventional ink jet recording head, since the lower electrode is provided in common to a plurality of piezoelectric elements, a voltage drop occurs when a large number of ink droplets are ejected at the same time by simultaneously driving a large number of piezoelectric elements. Occurs, the amount of displacement of the piezoelectric element becomes unstable, and there is a problem that the ink ejection characteristics deteriorate.

  In order to solve such a problem, a common lead electrode drawn from the lower electrode, which is a common electrode, is provided for each predetermined number of piezoelectric elements between individual lead electrodes drawn from the upper electrode, which is an individual electrode of the piezoelectric element. (See, for example, Patent Document 1).

JP 2003-127358 A (Claims, FIG. 3 etc.)

  However, in the structure as described above, since a common electrode is provided between the individual electrodes of the piezoelectric element, if water enters between the electrodes, a short circuit is caused between the individual electrode and the common electrode. There is a risk of damaging the piezoelectric element. In this “water”, the ambient air once heated by the heat generated by the piezoelectric element and the driving IC is cooled by stopping the heat generation of the piezoelectric element and the driving IC. As a result, the air is in the air close to the piezoelectric element and the driving IC. The water becomes water droplets and adheres to each member. Since the piezoelectric element is originally arranged in the piezoelectric element holding portion and is not easily affected by the outside, there is no high possibility that external moisture will directly adhere to the piezoelectric element as water droplets. However, a lead electrode such as an individual lead electrode or a common lead electrode connected to the piezoelectric element is composed of a first layer and a second layer provided on the first layer, and the width of the second layer is equal to that of the first layer. When configured so as to be larger than the width, there is a problem that external water easily flows into the piezoelectric element holding portion along the side surface of the first layer. That is, since the concave portion recessed inside the lead electrode is formed by the first layer and the second layer of the lead electrode provided on the substrate, the water flowing into the concave portion causes the side surface of the lead electrode to be affected by capillary action. Therefore, there is a problem that the piezoelectric element may flow into the piezoelectric element holding portion, resulting in damage to the piezoelectric element.

  Further, in the piezoelectric element holding part, when water generated by condensation or the like flows along the inner wall surface of the piezoelectric element holding part and flows into the concave portion of the lead electrode in the piezoelectric element holding part, the same phenomenon occurs. There was a problem of fear.

  Such a problem also exists between the individual electrodes. Similarly, when water flows between the individual electrodes, there is a possibility that the individual electrodes may be energized to cause a malfunction.

  In view of such circumstances, an object of the present invention is to provide a liquid ejecting head and a liquid ejecting apparatus capable of preventing water from flowing between the electrodes of the piezoelectric element through the side surface of the lead electrode described above. To do.

An aspect of the present invention that achieves the above object corresponds to a flow path forming substrate having a plurality of pressure generating chambers communicating with nozzle openings for ejecting liquid, and each pressure generating chamber on one side of the flow path forming substrate. A piezoelectric element, a plurality of lead electrodes drawn out from the piezoelectric element, and a piezoelectric element holding portion for protecting the piezoelectric element. A protective substrate to be bonded, and a bonding portion bonded on the lead electrode of the protective substrate is provided with a concave receiving portion for storing the adhesive in a region facing the lead electrode, In the liquid ejecting head, the adhesive is filled in concave portions at both ends in the width direction of the lead electrode.
In such an aspect, the adhesive can be reliably filled in the concave portion of the lead electrode by controlling the flow of the adhesive and actively flowing the adhesive between the lead electrodes. As a result, it is possible to reliably prevent water droplets from flowing into the piezoelectric element holding portion along the side surface of the lead electrode.

  Further, the concave portion of the lead electrode in the piezoelectric element holding portion is covered with a protective layer made of an adhesive that flows along the side surface of the lead electrode when the flow path forming substrate and the protective substrate are joined. Preferably it is. According to this, it is possible to reliably prevent water droplets condensed in the piezoelectric element holding portion from flowing into the concave portion of the lead electrode along the inner wall surface of the piezoelectric element holding portion.

  Further, it is preferable that a plurality of the accommodating portions are provided. According to this, the flow of the adhesive can be controlled more accurately.

  Further, in the vicinity of the end on the piezoelectric element holding portion side of the joint portion of the protective substrate, the accommodating portion is provided in a region facing the lead electrode, and in the vicinity of the opposite end, the accommodating portion is It is preferable to be provided in a region facing the lead electrode. According to this, the amount of the adhesive flowing out to the piezoelectric element holding part side can be increased, and the amount of the adhesive flowing out to the opposite side of the piezoelectric element holding part can be reduced.

  Further, the opening area of the housing portion provided in the vicinity of the end portion on the piezoelectric element holding portion side of the joint portion of the protective substrate is larger than the opening area of the housing portion provided in the vicinity of the opposite end portion thereof. Larger is preferred. According to this, the amount of the adhesive flowing out to the piezoelectric element holding portion side can be further increased, and the amount of the adhesive flowing out to the opposite side of the piezoelectric element holding portion can be further reduced.

  According to another aspect of the invention, there is provided a liquid ejecting apparatus including any one of the liquid ejecting heads described above. According to this, a highly reliable liquid ejecting head can be provided.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
FIG. 1 is an exploded perspective view showing a schematic configuration of an ink jet recording head which is an example of a liquid ejecting head according to Embodiment 1 of the present invention. FIG. 2 is a plan view of FIG. FIG.

  As shown in the figure, the flow path forming substrate 10 is made of a silicon single crystal substrate having a (110) crystal plane orientation in this embodiment, and an elastic film 50 made of silicon dioxide by thermal oxidation in advance on one surface thereof. Is formed.

  In the flow path forming substrate 10, pressure generating chambers 12 partitioned by a plurality of partition walls 11 are arranged in parallel in the width direction (short direction) by anisotropic etching from the other surface side. In addition, an ink supply path 14 and a communication path 15 are partitioned by a partition wall 11 on one end side in the longitudinal direction of the pressure generating chamber 12 of the flow path forming substrate 10. In addition, a communication portion 13 constituting a part of the reservoir 100 serving as an ink chamber (liquid chamber) common to the pressure generation chambers 12 is formed at one end of the communication passage 15. That is, the flow path forming substrate 10 is provided with a liquid flow path including a pressure generation chamber 12, a communication portion 13, an ink supply path 14, and a communication path 15.

  The ink supply path 14 communicates with one end side in the longitudinal direction of the pressure generation chamber 12 and has a smaller cross-sectional area than the pressure generation chamber 12. For example, in the present embodiment, the ink supply path 14 has a width smaller than the width of the pressure generation chamber 12 by narrowing the flow path on the pressure generation chamber 12 side between the reservoir 100 and each pressure generation chamber 12 in the width direction. It is formed with. As described above, in this embodiment, the ink supply path 14 is formed by narrowing the width of the flow path from one side. However, the ink supply path may be formed by narrowing the width of the flow path from both sides. Further, the ink supply path may be formed by narrowing from the thickness direction instead of narrowing the width of the flow path. Further, each communication path 15 communicates with the side of the ink supply path 14 opposite to the pressure generation chamber 12 and has a larger cross-sectional area than the width direction (short direction) of the ink supply path 14. In this embodiment, the communication passage 15 is formed with the same cross-sectional area as the pressure generation chamber 12.

  In other words, the flow path forming substrate 10 is connected to the pressure generation chamber 12, the ink supply path 14 having a smaller cross-sectional area in the short direction of the pressure generation chamber 12, the ink supply path 14, and the ink supply. A communication passage 15 having a cross-sectional area larger than the cross-sectional area in the short direction of the path 14 is provided by being partitioned by a plurality of partition walls 11.

  Further, on the opening surface side of the flow path forming substrate 10, a nozzle plate 20 having a nozzle opening 21 communicating with the vicinity of the end of each pressure generating chamber 12 on the side opposite to the ink supply path 14 is provided with an adhesive. Or a heat-welded film or the like.

  On the other hand, the elastic film 50 is formed on the side opposite to the opening surface of the flow path forming substrate 10 as described above, and the insulator film 55 is laminated on the elastic film 50. Further, the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80 are sequentially stacked on the insulator film 55 to constitute the piezoelectric element 300. In the present embodiment, the upper electrode film 80 is patterned together with the piezoelectric layer 70 to form individual electrodes of each piezoelectric element 300, and the lower electrode film 60 is continuously formed in the parallel direction of the piezoelectric elements 300. It is provided and serves as a common electrode common to the plurality of piezoelectric elements 300. Here, the piezoelectric element 300 refers to a portion including the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80, and a portion in which piezoelectric distortion occurs due to application of voltage to both electrodes is referred to as a piezoelectric active portion 320. In addition, the piezoelectric element 300 and a diaphragm that is displaced by driving the piezoelectric element 300 are collectively referred to as an actuator device. In the above-described example, the elastic film 50, the insulator film 55, and the lower electrode film 60 function as a diaphragm. However, the elastic film 50 and the insulator film 55 are not provided, and only the lower electrode film 60 is left. The electrode film 60 may be a diaphragm.

  Furthermore, an individual lead electrode 90 that is one of the lead electrodes is connected to the upper electrode film 80 that is an individual electrode of each piezoelectric element 300. In the present embodiment, one end of each individual lead electrode 90 extends to the vicinity of the communication portion 13 along the longitudinal direction of the piezoelectric element 300, and is connected to a drive circuit 120 mounted on a protective substrate 30 described later. It is electrically connected via the connection wiring 121.

  On the other hand, the lower electrode film 60 that is a common electrode of each piezoelectric element 300 has a common lead electrode 91 that is one of the lead electrodes at a predetermined ratio, for example, one ratio with respect to ten piezoelectric elements 300. It is connected. The common lead electrode 91 is formed in a region between the individual lead electrodes 90, and similarly to the individual lead electrode 90, one end thereof extends to the vicinity of the communication portion 13 and is electrically connected to the drive circuit 120. In the present embodiment, the other end portion of the common lead electrode 91 extends to the partition wall 11 that defines the pressure generation chamber 12, and the width of the common lead electrode 91 is larger than the width of the partition wall 11. It is formed with a narrow width. This is for preventing the displacement of the diaphragm due to the driving of the piezoelectric element 300 from being hindered by the presence of the common lead electrode 91 in the displacement region of the diaphragm.

  On the flow path forming substrate 10 on which such a piezoelectric element 300 is formed, a protective substrate 30 having a piezoelectric element holding portion 32 capable of ensuring a space that does not hinder its movement in a region facing the piezoelectric element 300 is provided. For example, they are joined via an adhesive layer 35 made of an epoxy or urethane adhesive. The protective substrate 30 only needs to have a space that does not hinder the movement of the piezoelectric element 300, and the space may be sealed or unsealed.

  Then, on the surface of the joint portion 37 of the protective substrate 30 to be joined to the individual lead electrode 90 and the common lead electrode 91 provided on the flow path forming substrate 10, as shown in FIGS. A plurality of concave accommodating portions 371 are provided at equal intervals in a direction in which the individual lead electrodes 90 are extended in regions facing each other between the individual lead electrodes 90 formed on the substrate 10. Note that the shape and number of the accommodating portions 371 can be arbitrarily set. Here, FIG. 3 is a top transparent view of the bonded portion when the protective substrate is bonded to the flow path forming substrate, and FIG. 4 is a B-B ′ cross-sectional view shown in FIG. 3. Further, although not shown, a plurality of accommodating portions 371 are also provided at equal intervals in the width direction of the joint portion 37 in the region facing the individual lead electrode 90 and the common lead electrode 91 of the joint portion 37. In the following, a description will be given between the individual lead electrodes 90, but the same can be considered between the individual lead electrodes 90 and the common lead electrode 91.

  The individual lead electrode 90 is formed on a first layer made of titanium tungsten (TiW), nickel (Ni), chromium (Cr), nickel chromium (NiCr) alloy or the like, and is formed on, for example, gold (Au). It is comprised with the 2nd layer which consists of. The width of the first layer 901 is narrower than the width of the second layer 902. On the outside of the first layer 901 of the individual lead electrode 90, between the insulator film 55 and the second layer 902, A recessed portion 90 a that is recessed inside the individual lead electrode 90 is formed. As shown in FIG. 4, the recesses 90 a at both ends in the width direction of the individual lead electrode 90 are filled with the adhesive 35 that has flowed in when the flow path forming substrate 10 and the protective substrate 30 are joined to the flow path forming substrate 10. Has been.

  Here, although details will be described later, in this embodiment, the accommodating portion 371 is formed in the joint portion 37 of the protective substrate 30, and the flow of the adhesive 35 is performed when the flow path forming substrate 10 and the protective substrate 30 are joined. Thus, the adhesive 35 can surely flow into the concave portion 90a of the individual lead electrode 90. As a result, the adhesive 35 is surely filled in the recesses 90 a of the individual lead electrodes 90 as compared with the case where the accommodating portion 371 is not formed. Therefore, even if water flows into the concave portion of the individual lead electrode 90 outside (in a through hole 33 described later), the water surely flows into the piezoelectric element holding portion 32 along the side surface of the individual lead electrode 90. Can be prevented.

  The protective substrate 30 is provided with a reservoir portion 31 that constitutes at least a part of the reservoir 100. In this embodiment, the reservoir portion 31 is formed across the protective substrate 30 in the thickness direction and across the width direction of the pressure generating chamber 12, and as described above, the reservoir portion 31 is connected to the communication portion 13 of the flow path forming substrate 10. A reservoir 100 is formed which communicates with each other and serves as a common liquid chamber for the pressure generating chambers 12.

  Further, the protective substrate 30 is further provided with a through hole 33 that penetrates the protective substrate 30 in the thickness direction. Then, the vicinity of the end portion of the individual lead electrode 90 drawn from each piezoelectric element 300 is provided so as to be exposed in the through hole 33.

  Further, a drive circuit 120 for driving the piezoelectric elements 300 arranged in parallel is fixed on the protective substrate 30. For example, a circuit board or a semiconductor integrated circuit (IC) can be used as the drive circuit 120. The drive circuit 120 and the individual lead electrode 90 are electrically connected via a connection wiring 121 made of a conductive wire such as a bonding wire.

  In addition, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded onto the protective substrate 30. Here, the sealing film 41 is made of a material having low rigidity and flexibility, and one surface of the reservoir portion 31 is sealed by the sealing film 41. The fixing plate 42 is made of a hard material such as metal. Since the region of the fixing plate 42 facing the reservoir 100 is an opening 43 that is completely removed in the thickness direction, one surface of the reservoir 100 is sealed only with a flexible sealing film 41. Has been.

  In such an ink jet recording head of this embodiment, ink is taken in from an external ink supply means (not shown), filled with ink from the reservoir 100 to the nozzle opening 21, and then in accordance with a recording signal from the drive circuit 120. Applying a voltage between each of the lower electrode film 60 and the upper electrode film 80 corresponding to the pressure generation chamber 12 to bend and deform the elastic film 50, the insulator film 55, the lower electrode film 60, and the piezoelectric layer 70. As a result, the pressure in each pressure generating chamber 12 increases and ink droplets are ejected from the nozzle openings 21.

  Next, a method for manufacturing such an ink jet recording head will be described. First, as shown in FIG. 5, the elastic film 50, the insulator film 55, and the lower electrode film 60 are sequentially formed on the surface of the flow path forming substrate 10, and the lower electrode film 60 is patterned into a predetermined shape.

  Next, as shown in FIG. 6, the piezoelectric layer 70 and the upper electrode film 80 are sequentially formed on the flow path forming substrate 10, and the piezoelectric layer 70 and the upper electrode film 80 are patterned to form each pressure generating chamber. The piezoelectric element 300 is formed in the region to be 12.

  Then, after forming the individual lead electrodes 90 connected to the piezoelectric elements 300, as shown in FIG. 7, the protective substrate 30 holding the plurality of patterned piezoelectric elements 300 is bonded onto the flow path forming substrate 10. 35 is joined. The protective substrate 30 is preliminarily formed with a reservoir portion 31, a piezoelectric element holding portion 32, and the like.

  Here, on both ends in the width direction of the first layer 901 of the individual lead electrode 90, a recess 90 a that is recessed inside the individual lead electrode 90 is formed between the insulator film 55 and the second layer 902. When the flow path forming substrate 10 and the protective substrate 30 are joined, the concave portion 90 a is narrow and the adhesive 35 has a high viscosity, so that the adhesive 35 is difficult to flow into the concave portion 90 a of the individual lead electrode 90. For this reason, since the concave portion 90a is not sufficiently filled with the adhesive 35, a gap remains between the adhesive 35 and the concave portion 90a. Moisture having a low viscosity is transmitted to the remaining portion and is carried to the vicinity of the piezoelectric element 300.

  Therefore, in the present embodiment, as described above, by providing a plurality of concave accommodating portions 371 on the surface of the joint portion 37 of the protective substrate 30 by etching or the like, the flow of the adhesive 35 is controlled and the adhesive 35 is applied. The individual lead electrode 90 can flow into the recess 90a. Specifically, when bonding the flow path forming substrate 10 and the protective substrate 30, a part of the adhesive 35 flows into the housing portion 371, so that the adhesive 35 is interposed between the individual lead electrodes 90. Gravitate. As a result, the adhesive 35 is surely filled in the recesses 90 a of the individual lead electrodes 90.

  Next, as shown in FIG. 8, the pressure generation chamber 12, the communication part 13, the ink supply path 14, the communication path 15, and the like are formed on the flow path forming substrate 10.

  After that, the nozzle plate 20 having the nozzle openings 21 formed on the surface of the flow path forming substrate 10 opposite to the protective substrate 30 is joined, and the compliance substrate 40 is joined to the protective substrate 30 to obtain the structure described above. An ink jet recording head is manufactured.

  As described above, in the configuration of the present embodiment, the concave portion 90a of the individual lead electrode 90 is reliably filled with the adhesive 35. The entry into the piezoelectric element holding portion 32 can be reliably prevented.

(Embodiment 2)
In the present embodiment, as shown in FIG. 9, the accommodating portion 371 on the piezoelectric element holding portion 32 side is provided in a region facing the individual lead electrodes 90, and the accommodating portion 371 on the through hole 33 side is connected to the individual lead electrode 90. It is provided in the area | region which opposes, and the flow of the adhesive agent 35 can be precisely controlled so that it may mention later.

  Further, as shown in FIG. 10, a protective layer 351 is formed on the side surface of the individual lead electrode 90 in the piezoelectric element holding portion 32. By providing this protective layer 351, it is possible to reliably prevent water droplets condensed in the piezoelectric element holding part 32 from flowing into the recesses 90 a of the individual lead electrodes 90 along the inner wall surface of the piezoelectric element holding part 32. The protective layer 351 is preferably formed longer along the individual lead electrode 90, and more preferably formed so as to cover the periphery of the individual lead electrode 90. Since other components are the same as those in the first embodiment, description thereof is omitted.

  Next, a method for manufacturing the ink jet recording head according to the present embodiment will be described. Here, since the steps other than the step of joining the flow path forming substrate 10 and the protective substrate 30 are the same as in the first embodiment, only the steps will be described below.

  In the present embodiment, as described above, since the accommodating portion 371 on the piezoelectric element holding portion 32 side is provided in the region facing the individual lead electrodes 90, the flow path forming substrate 10 and the protective substrate 30 are joined. At this time, the adhesive on the piezoelectric element holding portion 32 side flows between the individual lead electrodes 90. As a result, the adhesive flows out into the piezoelectric element holding portion 32 along the concave portions 90a of the individual lead electrodes 90 in the piezoelectric element holding portion 32, so that the protective layer 351 is reliably formed.

  On the other hand, since the accommodating portion 371 on the through hole 33 side is provided in a region facing the individual lead electrode 90, when bonding the flow path forming substrate 10 and the protective substrate 30, the adhesive on the through hole 33 side is It will be drawn on the individual lead electrode 90 and it will be difficult to flow between the individual lead electrodes 90 on the through hole 33 side. As a result, it is possible to prevent the adhesive from flowing into the through hole 33 along the concave portion 90 a of the individual lead electrode 90 in the through hole 33.

  Here, if the adhesive is attached to the individual lead electrode 90 in the through-hole 33, there is a possibility that a wire bonding defect may occur between the individual lead electrode 90 and the connection wiring 121. As described above, since the adhesive can be prevented from flowing into the through hole 33 along the concave portion 90a of the individual lead electrode 90 in the through hole 33, such a problem does not occur.

  Thus, in the configuration of the present embodiment, it is possible to reliably prevent water droplets condensed in the piezoelectric element holding portion 32 from flowing into the concave portions 90a of the individual lead electrodes 90 along the inner wall surface of the piezoelectric element holding portion 32. In addition, wire bonding failure between the individual lead electrode 90 and the connection wiring 121 can be prevented.

(Embodiment 3)
In the present embodiment, as shown in FIG. 11, the accommodating portion 371 a provided on the through hole 33 side has an opening area smaller than the opening area of the accommodating portion 371 provided on the piezoelectric element holding portion 32 side. As described later, the flow of the adhesive can be precisely controlled.

  Further, in the present embodiment, as in the second embodiment, a protective layer 351 is formed on the side surface of the individual lead electrode 90 in the piezoelectric element holding portion 32. Since other components are the same as those in the first embodiment, description thereof is omitted.

  Next, a method for manufacturing the ink jet recording head according to the present embodiment will be described. Here, as in the second embodiment, only the step of joining the flow path forming substrate 10 and the protective substrate 30 will be described.

  In the present embodiment, as described above, since the accommodating portion 371 on the piezoelectric element holding portion 32 side is provided to have a larger opening area than the accommodating portion 371a on the through hole 33 side, the flow path forming substrate 10. When bonding the protective substrate 30 to the protective substrate 30, the adhesive on the piezoelectric element holding portion 32 side flows between the individual lead electrodes 90. As a result, the adhesive flows out into the piezoelectric element holding portion 32 along the concave portions 90a of the individual lead electrodes 90 in the piezoelectric element holding portion 32, so that the protective layer 351 is reliably formed.

  On the other hand, since the accommodating portion 371a on the through hole 33 side is provided to have an opening area smaller than the opening area of the accommodating portion 371, when the flow path forming substrate 10 and the protective substrate 30 are joined, the through hole The 33 side adhesive hardly flows between the individual lead electrodes 90. As a result, it is possible to prevent the adhesive from flowing into the through hole 33 along the concave portion 90 a of the individual lead electrode 90 in the through hole 33.

  As described above, even in the configuration of the present embodiment, it is possible to reliably prevent water droplets condensed in the piezoelectric element holding portion 32 from flowing into the concave portions 90 a of the individual lead electrodes 90 along the inner wall surface of the piezoelectric element holding portion 32. In addition, wire bonding failure between the individual lead electrode 90 and the connection wiring 121 can be prevented.

  Further, as shown in FIG. 12, the accommodating portion 371 a on the through hole 33 side may be provided in a region facing the individual lead electrode 90. Even if comprised in this way, when joining the flow-path formation board | substrate 10 and the protective substrate 30, the flow of an adhesive agent can be controlled similarly.

(Other embodiments)
As mentioned above, although each embodiment of this invention was described, this invention is not limited to embodiment mentioned above.

  In Embodiments 1 to 3 described above, the accommodating portions 371 and 371a have rectangular openings, but these opening shapes are not particularly limited, and may be parallelograms, for example.

  In the third embodiment, the opening area of the accommodating portion 371a is changed. However, the present invention is not limited to this. For example, the accommodating portion having the same opening area is provided at a narrower interval to substantially accommodate the portion. You may make it change the opening area of a part. Even if it does in this way, the same effect is acquired.

  Furthermore, in Embodiments 1 to 3, the housing portions 371 and 371a are not provided on the same line in the longitudinal direction of the joint portion 37 of the protective substrate 30, but the housing portions 371 and 371a may be provided on the same line.

  In the first to third embodiments, the adhesive is filled in the concave portions 90a of the individual lead electrodes 90 in all the regions of the individual lead electrodes 90 joined to the joint portions 37 of the protective substrate 30. In this case, the concave portion 90a of the individual lead electrode 90 may be filled with an adhesive.

  In the above-described embodiment, the ink jet recording head has been described as an example of the liquid ejecting head of the present invention. However, the basic configuration of the liquid ejecting head is not limited to the above-described configuration. The present invention covers a wide range of liquid ejecting heads, and can naturally be applied to those ejecting liquids other than ink. Other liquid ejecting heads include, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, organic EL displays, and FEDs (field emission displays). Examples thereof include an electrode material ejection head used for electrode formation, a bioorganic matter ejection head used for biochip production, and the like.

FIG. 3 is an exploded perspective view of the recording head according to the first embodiment. 2A and 2B are a plan view and a cross-sectional view of the recording head according to the first embodiment. FIG. 3 is a top transparent view of a joint portion of a protective substrate according to Embodiment 1. FIG. 4 is a B-B ′ sectional view shown in FIG. 3. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. FIG. 10 is a top transparent view of a joint portion of a protective substrate according to Embodiment 2. 6 is a cross-sectional view of individual lead electrodes in a piezoelectric element holding unit according to Embodiment 2. FIG. FIG. 10 is a top transparent view of a joint portion of a protective substrate according to Embodiment 3. FIG. 10 is a top transparent view of a joint portion of a protective substrate according to Embodiment 3.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Flow path formation board | substrate, 12 Pressure generation chamber, 20 Nozzle plate, 21 Nozzle opening, 30 Protection board | substrate, 31 Reservoir part, 32 Piezoelectric element holding | maintenance part, 33 Through-hole, 35 Adhesive agent, 37 Junction part, 40 Compliance board | substrate, 50 Elastic film, 55 insulator film, 60 lower electrode film, 70 piezoelectric film, 80 upper electrode film, 90 individual lead electrode, 90a recess, 91 common lead electrode, 100 reservoir, 120 drive circuit, 121 connection wiring, 300 piezoelectric element , 351 Protective layer, 371, 371a container

Claims (6)

A flow path forming substrate having a plurality of pressure generating chambers communicating with nozzle openings for ejecting liquid, a piezoelectric element provided on one surface side of the flow path forming substrate corresponding to each pressure generating chamber, and the piezoelectric element A plurality of lead electrodes drawn out, and a protective substrate having a piezoelectric element holding portion for protecting the piezoelectric element and bonded to the surface of the flow path forming substrate on the piezoelectric element side by an adhesive, The joint portion to be joined on the lead electrode of the protective substrate is provided with a concave housing portion for housing the adhesive in a region facing the lead electrode, and is formed in the concave portion at both ends in the width direction of the lead electrode. A liquid jet head characterized by being filled with the adhesive. The concave portion of the lead electrode in the piezoelectric element holding portion is covered with a protective layer made of an adhesive that flows along the side surface of the lead electrode when the flow path forming substrate and the protective substrate are joined. The liquid ejecting head according to claim 1. The liquid ejecting head according to claim 1, wherein a plurality of the accommodating portions are provided. In the vicinity of the end portion on the piezoelectric element holding portion side of the joint portion of the protective substrate, the housing portion is provided in a region facing the lead electrodes, and in the vicinity of the opposite end portion, the housing portion is the lead. The liquid ejecting head according to claim 3, wherein the liquid ejecting head is provided in a region facing the electrode. The opening area of the housing portion provided in the vicinity of the end portion on the piezoelectric element holding portion side of the joint portion of the protective substrate is larger than the opening area of the housing portion provided in the vicinity of the end portion on the opposite side. The liquid ejecting head according to claim 3, wherein the liquid ejecting head is a liquid ejecting head. A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1.

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