JP4968474B2 - Liquid ejecting head and liquid ejecting apparatus - Google Patents

Description

  The present invention relates to a liquid ejecting head and a liquid ejecting apparatus that eject droplets, and more particularly, to an ink jet recording head and an ink jet recording apparatus that eject ink droplets as droplets.

  An ink jet recording head that is a typical example of a liquid ejecting head that ejects liquid droplets includes, for example, a flow path forming substrate in which a pressure generating chamber is formed, and a piezoelectric element provided on one side of the flow path forming substrate. In some cases, ink droplets are ejected from nozzles by applying pressure in the pressure generating chamber by the displacement of the piezoelectric element.

  Such an ink jet recording head requires a driving IC (semiconductor integrated circuit) for driving the piezoelectric element. For example, the driving IC is fixed by an adhesive on a protective substrate bonded to the flow path forming substrate, and is electrically connected to each piezoelectric element or the like by a connection wiring made of a bonding wire (for example, Patent Documents). 1).

JP 2004-148813 A

  In such an ink jet recording head, an adhesive having a relatively high hardness after curing is generally used as an adhesive for adhering the driving IC. Specifically, a thermosetting adhesive such as an epoxy adhesive is used. By using such an adhesive, the driving IC can be firmly bonded to the protective substrate.

  However, if the driving IC is firmly bonded to the protective substrate with the adhesive in this way, deformation of the bonded body of the plurality of substrates such as the flow path forming substrate, the protective substrate, and the nozzle plate is restricted, and the nozzle is ejected from each nozzle. There is a problem that the ejection characteristics of the ink droplets vary, and the print quality is deteriorated.

  The above-described bonded body is formed by laminating extremely thin substrates and is flat in a normal use environment, but is deformed (warped) due to factors such as a change in environmental temperature. For example, in the manufacturing process, if the driving IC is bonded onto the protective substrate in a state where the bonded body is warped, deformation (removal of warpage) of the bonded body is restricted by the driving IC and the adhesive, and the bonding is performed. The body is kept in a warped state. If the bonded body is warped as described above, the ejection characteristics of the ink droplets ejected from the nozzles may vary because the piezoelectric element is also warped.

  Further, the connection wiring is connected to the driving IC bonded on the protective substrate by wire bonding, but depending on the hardness of the adhesive bonding the driving IC, the driving IC sinks due to the pressing force at that time. Therefore, there is a possibility that connection failure of the connection wiring may occur. Generation | occurrence | production of such a problem may be able to be solved by mixing a gap material (insulator) with an adhesive agent as described in Patent Document 1, for example. However, the gap material is not simply mixed with the adhesive. For example, even when the gap material is excessively mixed with the adhesive, there is a possibility that the above-described variation in the injection characteristics may be caused.

  Such a problem exists not only in an ink jet recording head that ejects ink droplets, but also in other liquid ejecting heads that eject droplets other than ink droplets.

  The present invention has been made in view of such circumstances, and can uniformize the ejection characteristics of droplets from the nozzles communicating with the pressure generation chambers arranged in a row and connect the connection wiring to the drive IC satisfactorily. An object of the present invention is to provide a liquid ejecting head and a liquid ejecting apparatus that can perform the above operation.

The present invention that solves the above-described problems includes a flow path forming substrate in which a plurality of pressure generating chambers communicating with nozzles for ejecting droplets are provided, and the pressure generating chamber provided on one surface side of the flow path forming substrate. And a protective substrate having a piezoelectric element holding portion that is bonded to a first surface of the flow path forming substrate that serves as the piezoelectric element side and protects the piezoelectric element; A bonding pad portion and a driving IC for driving the piezoelectric element fixed on the second surface opposite to the first surface of the protective substrate. In a region corresponding to the driving IC on the second surface of the substrate, a first adhesive layer made of an adhesive mixed with a granular gap material and a second adhesive made of an adhesive not mixed with the gap material. An adhesive layer, on the other side of the drive IC The region corresponding to the serial bonding pad portion, said first adhesive layer is formed, said driving IC is in a liquid-jet head, characterized in that it is bonded to the protective substrate.
In the present invention, since the gap material is mixed in the first adhesive layer, the driving IC does not sink even if the bonding pad portion of the driving IC is pressed, and the connection wiring is excellent in the bonding pad portion. Can be connected to. Further, since there is a second adhesive layer in which the gap material is not mixed in the region other than the first adhesive layer, deformation of the joined body is ensured while ensuring a bonding force for bonding the driving IC to the protective substrate. Without restricting more than necessary, the ejection characteristics of the droplets ejected from each nozzle can be made uniform.

  Here, the second adhesive layer is made of an adhesive that is more flexible in a cured state than the adhesive constituting the first adhesive layer, and faces the bonding pad portion on the other surface of the drive IC. It is preferable that a portion other than the region is bonded to the protective substrate by the second adhesive layer. It is desirable that at least the adhesive constituting the second adhesive layer is a silicone-based adhesive. In such a configuration, the deformation of the joined body is not substantially restricted by the second adhesive layer. Therefore, the ejection characteristics of the droplets ejected from each nozzle can be made uniform while the drive IC is satisfactorily bonded to the protective substrate by the first and second bonding layers.

The present invention also provides a flow path forming substrate in which a plurality of rows of pressure generating chambers communicating with nozzles for ejecting liquid droplets are provided, and a pressure change in the pressure generating chamber provided on one side of the flow path forming substrate. A piezoelectric substrate to be generated, a protective substrate having a piezoelectric element holding portion that is bonded to the first surface of the flow path forming substrate on the piezoelectric element side and protects the piezoelectric element, and a bonding pad portion on one surface And a driving IC for driving the piezoelectric element fixed on the second surface opposite to the first surface of the protective substrate, and having a second surface of the protective substrate. The area corresponding to the driving IC on the surface of the driving IC includes a first adhesive layer made of an adhesive mixed with a granular gap material, and a non-adhesive area where no adhesive is applied, and the other surface of the driving IC. In the region corresponding to the bonding pad portion of Said first adhesive layer is formed, said driving IC is in a liquid-jet head, characterized in that it is bonded to the protective substrate.
In the present invention, since the gap material is mixed in the first adhesive layer, the driving IC does not sink even if the bonding pad portion of the driving IC is pressed, and the connection wiring is excellent in the bonding pad portion. Can be connected to. In addition, since no adhesive layer is formed in the region other than the first adhesive layer, the deformation of the joined body is not restricted more than necessary, and the ejection characteristics of the droplets ejected from each nozzle are made uniform. can do.

  According to another aspect of the invention, there is provided a liquid ejecting apparatus including such a liquid ejecting head. According to the present invention, a liquid ejecting apparatus with improved reliability can be realized.

Hereinafter, the present invention will be described in detail based on embodiments.
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 the present embodiment, and FIG. 2 is a plan view of FIG. FIG. 3 is an enlarged sectional view showing the main part.

  As shown in the figure, the flow path forming substrate 10 is made of a silicon single crystal substrate having a plane orientation (110) in this embodiment, and an elastic film 50 made of silicon dioxide is previously formed on one surface thereof by thermal oxidation. Yes. In the flow path forming substrate 10, pressure generation chambers 12 partitioned by a plurality of partition walls 11 are arranged in parallel in the width direction (short direction). In addition, an ink supply path 13 and a communication path 14 are partitioned by a partition wall 11 at one end in the longitudinal direction of the pressure generating chamber 12 of the flow path forming substrate 10. In addition, a communication portion 15 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 14.

  A nozzle plate 20 having a nozzle 21 communicating with each pressure generating chamber 12 is fixed to the opening surface side of the flow path forming substrate 10 with an adhesive, a heat welding film, or the like. The nozzle plate 20 is formed of, for example, glass ceramics, a silicon single crystal substrate, stainless steel, or the like.

  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 formed on the elastic film 50. Further, a piezoelectric element 300 composed of a lower electrode film 60, a piezoelectric layer 70, and an upper electrode film 80 is formed on the insulator film 55. In the present embodiment, the lower electrode film 60 is used as a common electrode of the piezoelectric element 300 and the upper electrode film 80 is used as an individual electrode of the piezoelectric element 300. However, there is no problem even if this is reversed for convenience of a drive circuit and wiring. Further, here, the piezoelectric element 300 and a diaphragm that is displaced by driving the piezoelectric element 300 are collectively referred to as an actuator. The diaphragm is a portion that constitutes one surface of the pressure generating chamber 12 and is deformed by driving the piezoelectric element 300. In the present embodiment, the elastic film 50, the insulator film 55, and the lower electrode film 60 function as a diaphragm, but of course not limited to this, for example, without providing the elastic film 50 and the insulator film 55. Only the lower electrode film 60 may act as a diaphragm. Further, the piezoelectric element 300 itself may substantially serve as a diaphragm.

  On the flow path forming substrate 10, a protective substrate 30 having a piezoelectric element holding portion 31 capable of securing a space that does not hinder its movement in a region facing the piezoelectric element 300 is joined. Since the piezoelectric element 300 is formed in the piezoelectric element holding part 31, the piezoelectric element holding part 31 is not necessarily sealed, but is protected in a state hardly affected by the external environment. . The protective substrate 30 is provided with a reservoir portion 32 that constitutes at least a part of the reservoir 100. In the present embodiment, the reservoir portion 32 is formed through the protective substrate 30 in the thickness direction and across the width direction of the pressure generating chamber 12, and communicates with the communication portion 15 of the flow path forming substrate 10. A reservoir 100 which is an ink chamber common to the pressure generation chamber 12 is configured. A through hole 33 that penetrates the protective substrate 30 in the thickness direction is provided in a region between the piezoelectric element holding portion 31 and the reservoir portion 32 of the protective substrate 30. The lead electrode 90 drawn out from each piezoelectric element 300 is exposed in the through-hole 33 in the vicinity of its end. Examples of the material of the protective substrate 30 include glass, a ceramic material, a metal, a resin, and the like. The protective substrate 30 is preferably formed of a material that is substantially the same as the coefficient of thermal expansion of the flow path forming substrate 10.

  A compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded to a region corresponding to the reservoir portion 32 of the protective substrate 30. The sealing film 41 is made of a material having low rigidity and flexibility, and one surface of the reservoir portion 32 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.

  Further, a surface (second surface) opposite to the surface (first surface) to be bonded to the flow path forming substrate 10 of the protective substrate 30 and a region facing the piezoelectric element holding portion 31 is piezoelectric. A driving IC (semiconductor integrated circuit) 110 for driving the element 300 is fixed. The drive IC 110 has a rectangular planar shape, and is arranged so that the longitudinal direction thereof is along the parallel direction of the piezoelectric elements 300. Although not shown, an insulating film made of silicon dioxide is actually provided on the surface of the protective substrate 30, and a predetermined pattern of wiring is formed on the insulating film. The driving IC 110 is fixed on the protective substrate 30 with the wiring interposed therebetween.

  The drive IC 110 is electrically connected to each lead electrode 90 drawn from the piezoelectric element 300 and a wiring (not shown) on the protective substrate 30 by wire bonding. For example, the bonding pad portion 111 of the driving IC 110 and the lead electrode 90 are electrically connected by a connection wiring 120 made of a bonding wire and extending into the through hole 33.

  Here, the driving IC 110 is bonded onto the protective substrate 30 with an adhesive, but in this embodiment, first, a region corresponding to the bonding pad portion 111 has a granular gap material 211 made of an insulating material. The first adhesive layer 210 made of a mixed adhesive is bonded to the protective substrate 30. The other region of the driving IC 110 constitutes the second adhesive layer 220 made of an adhesive not mixed with the gap material, more specifically, the first adhesive layer 210 not mixed with the gap material 211. It is joined to the protective substrate 30 by a second adhesive layer 220 made of an adhesive having a lower hardness in the cured state than the adhesive. The gap material 211 included in the first adhesive layer 210 is sandwiched between the drive IC 110 and the protective substrate 30.

In the present embodiment, the first adhesive layer 210 is continuously formed in a region facing the plurality of bonding pad portions 111. Of course, the first adhesive layer 210 may be formed independently in a region facing each bonding pad portion 111. The adhesive used as the first adhesive layer 210 is not particularly limited, but an adhesive having a relatively high hardness in a cured state, for example, an epoxy adhesive is preferably used. The material of the granular gap material 211 included in the first adhesive layer 210 is not particularly limited as long as it is an insulating material. For example, a resin material such as hard plastic, silicon oxide (SiO _x ), nitriding is used. Examples thereof include silicon (SiN) and tantalum oxide (TaO _x ). The particle shape of the gap material 211 is not particularly limited, but is preferably spherical. Furthermore, it is preferable that the particle diameter of each gap material 211 is substantially uniform.

  The adhesive used for the second adhesive layer 220 is preferably an adhesive having a relatively high flexibility in the cured state, and at least has a higher flexibility in the cured state than the first adhesive layer 210. An adhesive is preferred. The adhesive used for the second adhesive layer 220 is preferably a highly flexible adhesive as described above, and is preferably a moisture-curing adhesive. Specifically, for example, a silicone-based adhesive is preferably used.

  By bonding the driving IC 110 to the protective substrate 30 by using the first and second adhesive layers 210 and 220 as described above, the driving IC 110 can be bonded to the protective substrate 30 well, and the bonding pad portion 111 of the driving IC 110 can be bonded. Thus, the connection wiring 120 can be connected well. Specifically, since the gap material 211 is mixed in the first adhesive layer 210 provided in the region corresponding to the bonding pad portion 111, the connection wiring 120 is excellently bonded to the bonding pad portion 111 of the driving IC 110 by wire bonding. Can be connected to. When connecting the connection wiring 120 to the bonding pad portion 111 by wire bonding, the bonding pad portion 111 of the protective substrate 30 is pressurized by the capillary. If the gap material 211 is not mixed with the first adhesive layer 210, the driving IC 110 may sink due to the pressure applied by the capillary. That is, the first adhesive layer 210 is deformed and the drive IC 110 is displaced, and the connection wiring 120 may not be connected to the bonding pad portion 111 satisfactorily.

  However, in the present invention, since the gap material 211 is mixed with the first adhesive layer 210, the drive IC 110 comes into contact with the gap material 211 even when the bonding pad portion 111 is pressurized by the capillary. Sinking is prevented. Therefore, the connection wiring 120 can be satisfactorily connected to the bonding pad portion 111.

  The mixing amount of the gap material 211 is not particularly limited. However, when the gap material 211 is excessively mixed, the adhesive force of the first adhesive layer 210 is reduced, and there is a possibility of causing poor adhesion between the driving IC 110 and the protective substrate 30. It is necessary to make an appropriate decision in consideration of this point. However, in the configuration of the present embodiment, since the portion other than the bonding pad portion 111 of the driving IC 110 is bonded to the protective substrate 30 by the second adhesive layer 220, the first adhesive layer 210 is considered without considering adhesiveness. A relatively large number of gap materials 211 may be mixed. As a result, the above-described sinking of the driving IC 110 can be more reliably prevented.

  Furthermore, since the gap material 211 is mixed only in the first adhesive layer 210, the ejection characteristics (for example, ejection speed) of the ink droplets ejected from the nozzles 21 arranged in a row can be made uniform.

  Since the second adhesive layer 220 is formed of an adhesive having a relatively high flexibility in a cured state and is not mixed with a gap material, a plurality of substrates such as the flow path forming substrate 10, the protective substrate 30, and the nozzle plate 20 are formed. It plays a role of allowing deformation accompanying temperature change of the joined body. In addition, the presence of the second adhesive layer 220 ensures a sufficient bonding force for bonding the drive IC 110 onto the protective substrate 30.

  For example, when the environmental temperature changes and the temperature of the bonded body rises, the bonded body of a plurality of substrates may be warped, for example, on the protective substrate 30 side due to a difference in linear expansion coefficient between the substrates. The warp generated in the joined body is eliminated with the subsequent temperature decrease. That is, the joined body deforms as the temperature rises and falls. Such deformation of the joined body is allowed by the deformation of the second adhesive layer 220. Since the first adhesive layer 210 is made of an adhesive having a relatively high hardness and the gap material 211 is also mixed, the deformation of the joined body is restricted, but the formed area is small, Will not be affected.

  And since a deformation | transformation of a joining body is accept | permitted, a joining body will be in a flat state at least at normal temperature. Therefore, the ejection characteristics (for example, ejection speed) of the ink droplets ejected from the nozzles 21 arranged in a row can be made uniform. For example, even when the ink jet recording head is stored at a relatively high environmental temperature, the variation in the ejection characteristics of the ink droplets ejected from each nozzle 21 can be minimized.

  Here, each of the ink jet recording head of the example in which the driving IC is bonded to the protective substrate with the first and second adhesives, and the ink jet recording head of the comparative example in which the driving IC is bonded only with the epoxy adhesive. The ejection characteristics (ejection amount) of the ink droplet at the nozzle position were examined. Specifically, the ink jet recording heads of the example and the comparative example were left in a temperature environment of about 60 ° C. for 5 days, and the change in the ejection amount of ink droplets before and after that was examined. FIG. 4 is a graph showing a tendency of ink droplet ejection characteristics at the nozzle positions.

  As shown in FIG. 4A, in the ink jet recording head of the embodiment, the first adhesive layer and the second adhesive layer are formed on the surface of the drive IC on the side of the protective substrate 30 before and after being left. Thus, there was almost no difference in the amount of ink droplets ejected between the region where the drive ICs were joined (the drive IC joining region) and the region where the drive ICs on the outer sides were not joined. In addition, the change in the injection characteristics before and after being left alone was extremely small. That is, the amount of ink droplets ejected from each nozzle is substantially uniform regardless of the nozzle position in the direction in which the piezoelectric elements are arranged.

  On the other hand, in the ink jet recording head of the comparative example, as shown in FIG. 4B, before leaving, an epoxy-based adhesive in which a gap material is mixed on the entire surface of the driving IC on the protective substrate 30 side. There was almost no difference in the amount of ink droplets ejected between the region where the adhesive layer made of the agent was formed and the region where the drive ICs on both sides of the adhesive layer were not joined. However, after being left alone, the injection amount in the drive IC bonding region increases as a whole, and as a result, the injection amount in the region where the drive IC is not bonded is relatively larger than the injection amount in the region where the drive IC is bonded. Showed a tendency to decrease. When a plurality of drive ICs are mounted along the direction in which the piezoelectric elements are arranged side by side, the ink droplet ejection amount in the region between the drive ICs is also greater than the ejection amount in the region where the drive ICs are joined. Also show a relatively decreasing trend.

  By the way, as a factor of variation in the ejection amount in the conventional ink jet recording head, it is conceivable that the adhesive is cured by being left in a high temperature environment. When the driving IC is bonded to the protective substrate using an epoxy adhesive, the adhesive may not be completely cured during the manufacturing process. In this case, for example, the adhesive is completely cured by leaving the product in a high temperature environment. However, at that time, as described above, the adhesive is cured in a state where the bonded body of the plurality of substrates is warped, and the bonded body is fixed in a state where the warped is generated even when the environmental temperature is lowered. In addition, it is considered that the ejection amount of ink droplets varies due to the warpage of the joined body.

  As is clear from these results, the ejection amount of ink droplets ejected from each nozzle 21 is made uniform by joining the driving IC 110 to the protective substrate 30 by the first and second adhesive layers 210 and 220. can do.

  Although one embodiment of the present invention has been described above, of course, the present invention is not limited to such an embodiment.

  For example, in this embodiment, the driving IC 110 is joined to the protective substrate 30 by the second adhesive layer 220 together with the first adhesive layer 210. However, the present invention is not limited to this, and the adhesive force can be ensured. The driving IC 110 may be bonded to the protective substrate 30 only by the first adhesive layer 210. Specifically, a first adhesive layer is formed in a region corresponding to the bonding pad portion 111 of the drive IC 110, and a non-adhesive region is used instead of the second adhesive layer 220 in a region not corresponding to the bonding pad portion 111. A space may be formed. In such a configuration, the heat accompanying the heat generation of the drive IC 110 is transmitted to the protective substrate 30 side via the first adhesive 210, and the deformation due to the heat of the protective substrate 30 is suppressed. However, since the deformation of the joined body is allowed also by this space, the jetting characteristics can be made uniform.

  In addition, the first adhesive layer 210 is not necessarily formed of an adhesive having high hardness, and may be formed of an adhesive used for the second adhesive layer 220, for example, a silicone adhesive. Since the gap material 211 is mixed in the first adhesive layer 210, the driving IC 110 can be prevented from sinking regardless of the hardness of the adhesive.

  Further, for example, in the above-described embodiment, the thin film type ink jet recording head manufactured by applying the film forming and lithography process is taken as an example. However, the present invention is not limited to this. For example, a green sheet is attached. The present invention can be applied to a thick film type ink jet recording head formed by such a method.

  Such an ink jet recording head constitutes a part of a recording head unit including an ink flow path communicating with an ink cartridge or the like, and is mounted on the ink jet recording apparatus. FIG. 5 is a schematic view showing an example of the ink jet recording apparatus. As shown in FIG. 5, in the recording head units 1A and 1B having the ink jet recording head, cartridges 2A and 2B constituting ink supply means are detachably provided, and a carriage 3 on which the recording head units 1A and 1B are mounted. Is provided on a carriage shaft 5 attached to the apparatus body 4 so as to be movable in the axial direction. The recording head units 1A and 1B, for example, are configured to eject a black ink composition and a color ink composition, respectively. The driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and timing belt 7 (not shown), so that the carriage 3 on which the recording head units 1A and 1B are mounted is moved along the carriage shaft 5. The On the other hand, the apparatus body 4 is provided with a platen 8 along the carriage shaft 5, and a recording sheet S which is a recording medium such as paper fed by a paper feed roller (not shown) is conveyed onto the platen 8. It is like that.

  In the above-described embodiment, the ink jet recording head has been described as an example of the liquid ejecting head. However, the present invention is widely applied to all liquid ejecting heads, and the liquid ejecting ejects a liquid other than ink. Of course, it can also be applied to the head. 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. 2 is an exploded perspective view of a recording head according to an embodiment. 2A and 2B are a plan view and a cross-sectional view of a recording head according to an embodiment. FIG. 3 is an enlarged cross-sectional view of a recording head according to an embodiment. It is a graph which shows the tendency of the ejection amount of the ink droplet in a nozzle position. 1 is a schematic diagram of a recording apparatus according to an embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Flow path formation board | substrate, 12 Pressure generation chamber, 20 Nozzle plate, 21 Nozzle, 30 Protection board | substrate, 31 Piezoelectric element holding | maintenance part, 32 Reservoir part, 40 Compliance board | substrate, 50 Elastic film, 60 Lower electrode film, 70 Piezoelectric layer, 80 upper electrode film, 100 reservoir, 110 drive IC, 120 drive wiring, 210 first adhesive layer, 211 gap material, 220 second adhesive layer, 300 piezoelectric element

Claims (5)

A flow path forming substrate in which a plurality of pressure generating chambers communicating with nozzles for ejecting liquid droplets are provided; and a piezoelectric element that is provided on one side of the flow path forming substrate and causes a pressure change in the pressure generating chamber; A protective substrate having a piezoelectric element holding portion that is bonded to the first surface of the flow path forming substrate, which is the piezoelectric element side surface, and protects the piezoelectric element; a bonding pad portion is provided on one surface; A driving IC for driving the piezoelectric element, the direction of which is fixed on the second surface opposite to the first surface of the protective substrate;
In a region corresponding to the driving IC on the second surface of the protective substrate, a first adhesive layer made of an adhesive mixed with a granular gap material and a first adhesive made of an adhesive not mixed with the gap material. Two adhesive layers,
The liquid ejecting head according to claim 1, wherein the first adhesive layer is formed in a region corresponding to the bonding pad portion on the other surface of the driving IC, and the driving IC is bonded to the protective substrate.   The second adhesive layer is made of an adhesive that is more flexible in the cured state than the adhesive that constitutes the first adhesive layer, and other than the region facing the bonding pad portion on the other surface of the drive IC. The liquid ejecting head according to claim 1, wherein the portion is bonded to the protective substrate by the second adhesive layer.   The liquid ejecting head according to claim 2, wherein the adhesive constituting at least the second adhesive layer is a silicone-based adhesive. A flow path forming substrate in which a plurality of pressure generating chambers communicating with nozzles for ejecting liquid droplets are provided; and a piezoelectric element that is provided on one side of the flow path forming substrate and causes a pressure change in the pressure generating chamber; A protective substrate having a piezoelectric element holding portion that is bonded to the first surface of the flow path forming substrate, which is the piezoelectric element side surface, and protects the piezoelectric element; a bonding pad portion is provided on one surface; A driving IC for driving the piezoelectric element, the direction of which is fixed on the second surface opposite to the first surface of the protective substrate;
A region corresponding to the drive IC on the second surface of the protective substrate includes a first adhesive layer made of an adhesive mixed with a granular gap material, and a non-adhesive region where no adhesive is applied,
The liquid ejecting head according to claim 1, wherein the first adhesive layer is formed in a region corresponding to the bonding pad portion on the other surface of the driving IC, and the driving IC is bonded to the protective substrate.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1.

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