Liquid discharge head

Abstract

To provide a liquid discharge head which can inhibit expansion of voids.SOLUTION: A liquid discharge head 21 includes: a first substrate 1 having a first surface 23; and a second substrate 17 having a second surface 24. The first substrate 1 and the second substrate 17 are joined through an adhesive. The first surface 23 is formed with a first protruding part 7 protruding to the second surface 24, and the second surface 24 is formed with a second protruding part 8 protruding to the first surface 23.SELECTED DRAWING: Figure 2

Description

Technical Field

[0005]

[0001] The present invention relates to a liquid ejection head composed of a plurality of substrates.

Background Art

[0002] A recording apparatus that ejects a liquid onto a recording medium such as paper for recording has a liquid ejection head including a liquid ejection port for ejecting the liquid and a pressure generating element for generating pressure for ejection. The liquid ejection head may be formed by joining a plurality of substrates using an adhesive. As a typical example, there is a piezo head method in which a piezoelectric element is driven to eject a liquid.

[0003] When joining a plurality of substrates with an adhesive, it is important that there are no voids (regions where the adhesive is not applied; hereinafter referred to as voids) in the adhesive layer formed between the substrates. If there are voids in the adhesive layer, and if the voids expand due to various factors such as the thermal contraction of the adhesive itself or the pressure difference inside and outside the substrate, it can become a space through which the liquid can pass. That is, a liquid flow path is formed in a region where the adhesive should originally be formed. The region where the adhesive is formed in the liquid ejection head is a region necessary for separating the flow paths through which different colored liquids (inks) flow. Therefore, if the liquid flows through this region, functional or quality problems will occur.

[0004] Patent Document 1 discloses a method of suppressing the expansion of voids by forming convex portions on the substrate. When the expansion of the voids in the adhesive layer progresses, the voids collide with the convex portions, and further expansion of the voids is inhibited. In other words, the expansion of the voids can be blocked by the convex portions.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] In the method described in Patent Document 1, a protrusion is formed on only one of the substrates to be joined. Therefore, if a void occurs on the substrate side where the protrusion is not formed, there is a risk that the void will expand. This will be explained in detail using Figure 1. Figure 1 is a schematic diagram showing how a first substrate 1 on which a protrusion 7 is formed and a second substrate 17 on which no protrusion is formed are joined with adhesive 3. As shown in Figure 1(a), a void 2 occurs on the side of the second substrate 17 on which the protrusion is not formed. If the void 2 expands in this state, there is no obstacle to block its movement in the direction of its progression, so as shown in Figures 1(b) and (c), the void 2 expands into the flow channel 4, and the flow channel 4 and the void 2 become connected. The direction of void expansion is indicated by arrow 13. As a result, the liquid flowing in the flow channel 4 flows into the expanded void 5, causing functional or quality problems.

[0007] In view of the above problems, the present invention aims to provide a liquid discharge head that can further suppress the expansion of voids. [Means for solving the problem]

[0008] To solve the above problems, the present invention provides a liquid discharge head comprising a first substrate having a first surface and a second substrate having a second surface facing the first surface, wherein the first substrate and the second substrate are joined via an adhesive between the first surface and the second surface, characterized in that a first convex portion is formed on the first surface that protrudes toward the second surface, and a second convex portion is formed on the second surface that protrudes toward the first surface. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a liquid discharge head that can further suppress the expansion of voids. [Brief explanation of the drawing]

[0010] [Figure 1] Schematic diagram showing a conventional example. [Figure 2] Schematic diagram showing the liquid ejection head of the first embodiment. [Figure 3] Schematic diagram showing the liquid ejection head of the first embodiment. [Figure 4] Schematic diagram showing the liquid ejection head of the first embodiment. [Figure 5] Schematic diagram showing the liquid ejection head of the second embodiment. [Figure 6] Schematic diagram showing the liquid ejection head of the third embodiment. [Figure 7] Schematic diagram showing the liquid ejection head of the fourth embodiment. [Figure 8] Schematic diagram showing the liquid ejection head of the fifth embodiment. [Figure 9] Schematic diagram showing the liquid ejection head of the sixth embodiment. [Figure 10] Schematic diagram showing the liquid ejection head of the seventh embodiment. [Figure 11] Schematic diagram showing the liquid ejection head of the eighth embodiment. [Figure 12] Schematic diagram showing the liquid ejection head of the ninth embodiment. [Figure 13] Schematic diagram showing the liquid ejection head of the tenth embodiment. [Figure 14] Schematic diagram showing the liquid ejection head of the eleventh embodiment. [Figure 15] Schematic diagram showing the liquid ejection head of the twelfth embodiment. [Figure 16] Schematic diagram showing the liquid ejection head of the thirteenth embodiment. [Figure 17] Schematic diagram showing the liquid ejection head of the fourteenth embodiment. [Figure 18] Schematic diagram showing the liquid ejection head of the fifteenth embodiment. [Figure 19] Schematic diagram showing the liquid ejection head of the sixteenth embodiment. [Figure 20] Schematic diagram showing the liquid ejection head of the seventeenth embodiment. [Figure 21]Schematic diagram showing the liquid ejection head of the 18th embodiment. [Figure 22] Schematic diagram showing the liquid ejection head of the 19th embodiment. [Figure 23] Schematic diagram showing the liquid ejection head of the 20th embodiment. [Figure 24] Schematic diagram showing a method for manufacturing the convex portion. [Figure 25] Schematic diagram showing a method for manufacturing the convex portion. [Figure 26] Schematic diagram showing a method for manufacturing the convex portion. [Figure 27] Schematic diagram showing a method for manufacturing the convex portion. [Figure 28] Schematic diagram showing a method for manufacturing the convex portion. [Figure 29] Schematic diagram showing a method for manufacturing the convex portion. [Figure 30] Schematic diagram showing a method for manufacturing the convex portion.

Mode for Carrying Out the Invention

[0011] Hereinafter, preferred embodiments of the present invention will be described in detail based on the accompanying drawings. In each figure, the same members are denoted by the same reference numerals, and redundant descriptions are omitted.

[0012] (First Embodiment) The liquid ejection head of this embodiment is mounted on an inkjet printer (not shown). Although there are various forms of inkjet printers, generally, the printer is provided with a carriage (not shown) that can move in the scanning direction, and the carriage is provided with a liquid ejection head that ejects ink onto a printing medium. The ink passes from the ink tank through the liquid flow path and is ejected from the ejection port provided in the liquid ejection head onto the printing object. By repeating the scanning and ejection of the carriage, a desired pattern is printed.

[0013] Figure 2 is a schematic diagram showing a liquid discharge head 21 of this embodiment, formed by joining multiple substrates including a piezoelectric element 19 with an adhesive. Figure 2(a) is a perspective view of the liquid discharge head 21. Figure 2(b) is a cross-sectional view along the line U-U' shown in Figure 2(a). Figure 2(c) is an enlarged view of the area enclosed by the dashed line shown in Figure 2(b). The liquid discharge head 21 is composed of a first substrate 1, a second substrate 17, and a third substrate 22. A flow path 4 through which liquid flows is formed in the first substrate 1. A piezoelectric element 19 and the flow path 4 are formed in the second substrate 17. A discharge port 18 for discharging liquid onto an object such as paper is formed in the third substrate 22. The first substrate 1, the second substrate 17, and the third substrate 22 are joined together via an adhesive 3. The adhesive 3 is applied between the first surface 23 of the first substrate 1 and the second surface 24 facing the first surface 23. As shown in Figure 2(c), a protrusion 7 (also referred to as the first protrusion 7) is formed on the first substrate 1, and a second protrusion 8 is formed on the second substrate 17. The first protrusion 7 protrudes toward the second surface 24, and the second protrusion 8 protrudes toward the first surface 23.

[0014] Figure 3 is a schematic diagram illustrating the effects of this embodiment using the cross-sectional view shown in Figure 2(c). It shows the process of void 2 expanding. Void 2 exists in a part of the adhesive layer 3 between the first substrate 1 and the second substrate 17. Due to various factors such as shrinkage caused by heating to cure the adhesive 3 and pressure differences in the left and right spaces, void 2 expands according to arrow 13 (Figure 3(a)). When void 2 collides with the second protrusion 8, the direction of travel of void 2 changes from left to right in the drawing to downward in the drawing (Figure 3(b)). After that, when void 2 reaches the surface of the first substrate 1, it travels to the left again (Figure 3(c)). However, in the meantime, the curing of the adhesive 3 progresses, and the curing of the adhesive 3 is completed before void 2 reaches the flow path 4.

[0015] Therefore, in this embodiment, the distance over which the void 2 travels is increased by providing a protrusion on each of the two substrates to be joined. This further suppresses the expansion of the void 2. Also, because a protrusion is formed on each of the two substrates, regardless of whether the void 2 occurs on the first substrate side or the second substrate side, the void 2 will always collide with either the first protrusion 7 or the second protrusion 8. Thus, the expansion of the void 2 can be further suppressed. If the void 2 expands, the liquid in the flow path 4 may adhere to the piezoelectric element 19, potentially causing the piezoelectric element 19 to malfunction. According to this embodiment, malfunctions of the piezoelectric element 19 and the like can also be suppressed.

[0016] Figure 4(a) is a top view of the first substrate 1 around the first protrusion 7. Figure 4(b) is a cross-sectional view of the line AA' shown in Figure 4(a). Figure 4 omits the adhesive 3. The second protrusion 8 is also shown for illustrative purposes. The heights of the first protrusion 7 and the second protrusion 8 are approximately the same. Either the first protrusion 7 or the second protrusion 8 can be on the inside (flow channel 4 side) or the outside, but it is necessary to form them in a position where voids 2 are likely to occur does not occur between the first protrusion 7 and the second protrusion 8. Furthermore, to obtain a greater effect, it is preferable that a portion of the first protrusion 7 and the second protrusion 8 overlap by a certain amount or more in the vertical direction, and it is preferable that the sum of the heights of the first protrusion 7 and the second protrusion 8 is greater than or equal to the height (thickness) of the adhesive layer. As shown in Figure 4(a), the first protrusion 7 and the second protrusion 8 continuously surround the opening of the flow channel 4. This prevents void 2 from expanding into the flow path, regardless of where it forms.

[0017] (Second embodiment) A second embodiment will now be described. Similar parts in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. Figure 5(a) is a diagram of this embodiment corresponding to Figure 4(a). Figure 5(b) is a diagram of this embodiment corresponding to Figure 4(b). In this embodiment, the sides of the first protrusion 7 and the second protrusion 8 are curved. This allows the surface area of ​​the first protrusion 7 and the second protrusion 8 to be increased, and the distance over which the void 2 propagates can be further secured. Therefore, the expansion of the void 2 can be further suppressed.

[0018] (Third embodiment) A third embodiment will now be described. Similar parts in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. Figure 6(a) is a diagram of this embodiment corresponding to Figure 4(a). Figure 6(b) is a diagram of this embodiment corresponding to Figure 4(b). Unlike the first embodiment, the heights of the first protrusion 7 and the second protrusion 8 are different. Either the first protrusion 7 or the second protrusion 8 can be higher or lower, but the effect of the present invention can be further enhanced by placing the higher protrusion near the location where voids 2 are likely to occur. In addition, in the third embodiment as well, in order to obtain a greater effect, it is preferable that a portion of the first protrusion 7 and the second protrusion 8 overlap by a certain amount or more in the vertical direction, and it is preferable that the sum of the heights of the first protrusion 7 and the second protrusion 8 is greater than or equal to the height of the adhesive layer.

[0019] (Fourth embodiment) A fourth embodiment will now be described. Similar parts from the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. Figure 7(a) is a diagram of this embodiment corresponding to Figure 4(a). Figure 7(b) is a diagram of this embodiment corresponding to Figure 4(b). In the fourth embodiment, the sides of the first protrusion 7 and the second protrusion 8 are made into an uneven shape. This allows the surface area of ​​the protrusions to be increased, and the distance over which the void 2 propagates can be further secured. Therefore, the expansion of the void 2 can be further suppressed.

[0020] (Fifth embodiment) A fifth embodiment will now be described. Similar parts in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. Figure 8(a) is a diagram of this embodiment corresponding to Figure 4(a). Figure 8(b) is a diagram of this embodiment corresponding to Figure 4(b). The fifth embodiment is characterized in that the cross-sectional shapes of the first convex portion 7 and the second convex portion 8 are trapezoidal. By making the cross-sectional shapes of the first convex portion 7 and the second convex portion 8 trapezoidal, the surface area can be increased compared to a rectangle. This makes it possible to further increase the surface area of ​​the convex portion and to secure a greater distance for the propagation of the void 2. Therefore, the expansion of the void 2 can be further suppressed.

[0021] (Sixth embodiment) A sixth embodiment will now be described. Similar parts in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. Figure 9(a) is a diagram of this embodiment corresponding to Figure 4(a). Figure 9(b) is a diagram of this embodiment corresponding to Figure 4(b). In the sixth embodiment, the cross-sectional shapes of the first protrusion 7 and the second protrusion 8 are triangular. Because the cross-sectional shapes of the first protrusion 7 and the second protrusion 8 are triangular, the volume of the protrusions themselves can be made smaller, thereby reducing concerns about adhesion caused by a reduction in the volume of adhesive 3.

[0022] (Seventh Embodiment) A seventh embodiment will now be described. Similar parts from the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. Figure 10(a) is a diagram of this embodiment corresponding to Figure 4(a). Figure 9(b) is a diagram of this embodiment corresponding to Figure 4(b).

[0023] The seventh embodiment is a configuration in which two first protrusions 7 are arranged on the side of the first substrate 1 and one second protrusion 8 is arranged on the side of the second substrate 17. In this way, even if the number of first protrusions 7 and second protrusions 8 are not equal, a pair of protrusions can be formed by having one or more protrusions on each bonding surface. By providing more protrusions, the effects of the present invention can be further enhanced.

[0024] (Eighth embodiment) The eighth embodiment will now be described. Similar parts in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. Figure 11(a) is a diagram of this embodiment corresponding to Figure 4(a). Figure 11(b) is a diagram of this embodiment corresponding to Figure 4(b). The eighth embodiment is a configuration in which two first protrusions 7 are arranged on the side of the first substrate 1, and two second protrusions 8 are arranged on the side of the second substrate 17. That is, multiple first protrusions 7 and second protrusions 17 are formed. The effect of the present invention can be further enhanced by providing more protrusions in the path, but it is important to provide an appropriate number depending on the length of the installation area and the width of the protrusions. Regarding the position of the two sets of protrusions, it is preferable to arrange them far apart from each other in order to more reliably obtain the effect of the present invention with respect to the void 2. For this reason, it is preferable to arrange them in areas closer to the inside and outside of the area where the adhesive is applied.

[0025] (Ninth embodiment) A ninth embodiment will now be described. Similar parts from the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. Figure 12(a) is a diagram of this embodiment corresponding to Figure 4(a). Figure 12(b) is a diagram of this embodiment corresponding to Figure 4(b). The diagram shows a configuration in which 16 first protrusions 7 are arranged on the side of the first substrate 1, and 12 second protrusions 8 are arranged on the side of the second substrate 17. The protrusions are located so as to surround the flow path 4. In this way, by making the first protrusions 7 and the second protrusions 8 into separate block shapes, it is possible to secure a sufficient volume of adhesive 3 and maintain adhesion. That is, the first protrusions 7 and the second protrusions 8 intermittently surround the opening of the flow path 4.

[0026] (Tenth embodiment) A tenth embodiment will now be described. Similar parts in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. Figure 13(a) is a diagram of this embodiment corresponding to Figure 4(a). Figure 13(b) is a diagram of this embodiment corresponding to Figure 4(b). The thirteenth embodiment is characterized by varying the lengths of the first protrusion 7 and the second protrusion 8 depending on the direction and position. This makes it possible to suppress lateral expansion when the void is prone to expanding in the lateral direction of the figure, and to secure an adhesive area in the vertical direction because the formation area of ​​the protrusion is smaller. In other words, it is possible to achieve both suppression of void expansion and securing adhesive strength.

[0027] (11th embodiment) An eleventh embodiment will now be described. Similar parts from the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. Figure 14(a) is a diagram of this embodiment corresponding to Figure 4(a). Figure 14(b) is a diagram of this embodiment corresponding to Figure 4(b). In the diagonal direction, the distance from the flow path 4 to the end is long, while in the up, down, left, and right directions, it is shorter than in the diagonal direction. Therefore, there is a high concern that the void will expand in the up, down, left, and right directions and reach the flow path 4. In such a case, the protrusions in the diagonal direction may not be provided, and protrusions may only be provided in the up, down, left, and right directions. By providing protrusions only in the necessary areas in the necessary places, it is possible to achieve both securing adhesive strength and suppressing void expansion.

[0028] (12th embodiment) A twelfth embodiment will now be described. Similar parts from the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. Figure 15(a) is a diagram of this embodiment corresponding to Figure 4(a). Figure 15(b) is a diagram of this embodiment corresponding to Figure 4(b). A feature of this embodiment is that the first substrate 1 has a relief groove 14 for the adhesive 3 formed together with the first protrusion 7. The relief groove 14 is for containing excess adhesive in the recess and suppressing the adhesive from overflowing from the substrate. This not only suppresses the expansion of voids but also suppresses the overflow of adhesive.

[0029] Since the relief groove 14 may become a site for void formation, it is preferable to form the first protrusion 7 and the second protrusion 8 along the direction in which the relief groove 14 is formed. This effectively suppresses the expansion of voids caused by the relief groove 14. In Figure 15, the relief groove 14 is formed on the first substrate 1, but the relief groove 14 may also be formed on the second substrate 17. That is, it is sufficient for the relief groove 14 to be formed on at least one of the first substrate 1 or the second substrate 17.

[0030] (13th embodiment) A thirteenth embodiment will now be described. Similar parts from the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. Figure 16 is a schematic diagram illustrating the effects of this embodiment. Figure 16(a) is a diagram of this embodiment corresponding to Figure 4(a). Figures 16(b) to (d) are diagrams of this embodiment corresponding to Figure 4(b). Note that the recess 9 is not shown in Figure 16(a). This shows the process of void 2 expanding. A void 2 exists in a part of the adhesive layer 3 between the first substrate 1 and the second substrate 17 (Figure 16(b)). Due to various factors such as shrinkage caused by heating to cure the adhesive 3 and pressure differences in the left and right spaces, the void 2 expands according to the arrow 13 (Figure 16(c)). When the void 2 collides with the first convex portion 7, the direction of travel of the void 2 changes from the left direction in the drawing to the top direction in the drawing (Figure 16(d)). A recess 9 exists on the bonding surface of the second substrate 17. The first convex portion 7 and the concave portion 9 are not in contact. As shown in Figure 16(d), when the void 2 reaches the vicinity of the bottom of the concave portion 9, it moves to the left again. However, in the meantime, the adhesive 3 has been curing, and the curing of the adhesive 3 is completed before the void 2 reaches the channel 4.

[0031] Therefore, in this embodiment, the distance over which the void 2 travels is increased by combining the convex and concave portions. This further suppresses the expansion of the void 2. Furthermore, by inserting a portion of the first convex portion 7 into the concave portion 9, the void 2 will always collide with the first convex portion 7, regardless of whether the void 2 occurs on the first substrate side or the second substrate side. Thus, the expansion of the void 2 can be further suppressed.

[0032] The protrusions may be repurposed from existing protrusions such as wiring patterns. The width of the recess 9 must be wider than the width of the protrusion, and when joined, a certain amount or more of the protrusion must overlap and be housed in the recess 9. Furthermore, in order to obtain the full effect of the invention with the convex-concave structure, it is desirable to place it on the side closer to the flow path 4 or on the side closer to the opposite end within the area where bonding is performed. The figure shows an example in which the convex-concave structure is provided on the side closer to the flow path 4. Since the cross-sectional shape of both the first protrusion 7 and the recess 9 is rectangular, it is relatively easy to actually form the protrusion and recess 9.

[0033] In Figure 16, the first substrate 1 is provided with a protrusion 7 and the second substrate 17 is provided with a recess 9, but in this embodiment, the opposite may be true. That is, the first substrate 1 may be provided with a recess 9 and the second substrate 17 may be provided with a protrusion.

[0034] (14th embodiment) A 14th embodiment will now be described. Similar parts in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. Figure 17(a) is a diagram of this embodiment corresponding to Figure 4(a). Figure 17(b) is a diagram of this embodiment corresponding to Figure 4(b). Note that the recess 9 is not shown in Figure 17(a). The diagram shows a trapezoidal cross-sectional shape of the first convex portion 7 and a trapezoidal cross-sectional shape of the recess 9 provided on the second substrate 17. The width of the recess 9 is wider than the width of the convex portion, and it is necessary that a certain amount or more of the convex portion overlaps and is housed in the recess 9 when joined. Furthermore, in order to obtain the full effect of the invention with the convex-concave structure, it is desirable to place it on the side closer to the flow path 4 or on the side closer to the opposite end within the area where bonding is performed. Since the cross-sectional shapes of both the first convex portion 7 and the recess 9 are trapezoidal, the surface area can be increased, so the path until the voids connect becomes longer, making it less likely for them to become connected voids 5.

[0035] (15th embodiment) A 15th embodiment will now be described. Similar parts in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. Figure 18(a) is a diagram of this embodiment corresponding to Figure 4(a). Figure 18(b) is a diagram of this embodiment corresponding to Figure 4(b). Note that the recess 9 is not shown in Figure 18(a). The diagram shows a state in which two sets of convex-concave structures are provided, with the first convex portion 7 provided on the first substrate 1 having a rectangular cross-sectional shape and the recess 9 provided on the second substrate 17 having a rectangular cross-sectional shape. When providing two or more sets of convex-concave structures, in order to obtain the full effect of the invention, it is desirable to arrange them on the side closer to the flow path 4 and on the side closer to the end within the area where bonding is performed. By providing two or more sets of convex-concave structures, the effect of suppressing the generation of communication voids 5 can be increased.

[0036] (16th embodiment) A sixteenth embodiment will now be described. Similar parts from the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. Figure 19(a) is a diagram of this embodiment corresponding to Figure 4(a). Figure 19(b) is a diagram of this embodiment corresponding to Figure 4(b). The left side shows a high adhesive 3 and the right side shows a low adhesive 3'. When the thickness difference of adhesive 3 is non-uniform in the plane in this way, the lower areas can become the starting point 2 of a communication void. In this case, as shown in Figures 15(a) and 15(b), the present invention can be implemented only in areas close to the starting point 2 of the communication void. By providing protrusions only in the necessary areas in the necessary locations, the present invention can be implemented without concerns about adhesion.

[0037] (Embodiment 17) A 17th embodiment will now be described. Similar parts to those in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. Figure 20(a) is a top view of the wafer before cutting each element, (b) is a cross-sectional view of the wafer, (c) is an enlarged cross-sectional view of a part of the chip near the center of the wafer, and (d) is an enlarged cross-sectional view of a part of the chip near the outer edge of the wafer. This embodiment is one form of a convex-convex portion, showing how the present invention is implemented only on the chip near the outer edge of the wafer. As shown in Figure 20(b), there are cases where a second substrate 17 that is curved upward is joined to a flat first substrate 1. At this time, there is a high concern that a gap will occur between the adhesive 3 and the second substrate 17 at the wafer outer edge chip 15, so a starting point 2 of a communication void may occur at the wafer outer edge chip 15. In such cases, it is also possible to provide a convex-convex portion on the wafer outer edge chip 15 and leave nothing on the wafer central chip as in the conventional method. In this way, by providing convex portions only in the necessary areas in the necessary places, the effects of the present invention can be obtained without causing concerns about the adhesion of other areas.

[0038] (Embodiment 18) An 18th embodiment will now be described. Similar parts to those in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. Figure 21(a) is a top view of the wafer before cutting each element, (b) is a cross-sectional view of the wafer, (c) is an enlarged cross-sectional view of a part of the chip near the center of the wafer, and (d) is an enlarged cross-sectional view of a part of the chip near the outer edge of the wafer. This embodiment is one form of a convex-convex portion and shows how the present invention is implemented only on the chip near the center of the wafer. As shown in Figure 20(b), a second substrate 17 that is curved downwards may be joined to a flat first substrate 1. In this case, there is a high concern that a gap will occur between the adhesive 3 and the second substrate 17 at the central wafer chip 16, so a starting point 2 of a communication void may occur at the central wafer chip 16. In such a case, it is also possible to provide a convex-convex portion at the central wafer chip 16 and leave nothing at the outer wafer chip 15 as in the conventional method. In this way, by providing convex portions only in the necessary areas at the necessary locations, the effects of the present invention can be obtained without causing concerns about the adhesion of other areas.

[0039] (19th embodiment) A 19th embodiment will now be described. Similar parts from the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. Figure 22(a) is a top view, and (b) is a cross-sectional view of the dotted line section. The 20th embodiment is a form of convex-convex section, showing that three different color rows, 20, 20', and 20'', exist within a single chip. In this configuration, if ink leaks between the color rows, it can cause color mixing and may reduce print quality. Therefore, as shown in the figure, the present invention can be implemented only between color rows 20 and 20', and between color rows 20' and 20''. By providing convex sections only in the necessary areas where necessary, the present invention can be implemented without concerns about adhesion.

[0040] (20th embodiment) A 20th embodiment will now be described. Similar parts from the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. Figure 23(a) is a top view, and (b) is a cross-sectional view of the dotted line portion. This embodiment is a form of convex-convex portion, showing that three different color rows, color rows 20, 20', and 20'', exist within a single chip. If there is a concern that ink may leak outwards from the outer edge of the chip in this configuration, the present invention can be implemented only on the outer edge of the chip, as shown in the figure. By providing convex portions only in the necessary areas in the necessary locations, the present invention can be implemented without concerns about adhesion.

[0041] (Method for manufacturing the protrusion) Figure 24 shows the manufacturing method for the first protrusion 7, which has a rectangular cross-section. First, as shown in Figure 24(a), a photoresist 6 is formed on the surface of the first substrate 1, and the desired resist pattern shape is obtained by exposure, development, etc. Next, as shown in Figure 24(b), the first substrate 1 is processed by applying an etching component 10 from above the photoresist 6. The etching component 10 is a general dry etching gas, etc. Finally, as shown in Figure 24(c), the desired rectangular protrusion is obtained by removing the photoresist 6.

[0042] Figure 25 shows a method for manufacturing a first protrusion 7 having a curved side surface. First, as shown in Figure 25(a), a photoresist 6 is formed on the surface of the first substrate 1, and the desired resist pattern shape is obtained by exposure, development, etc. Next, as shown in Figure 25(b), the first substrate 1 is processed by applying an etching component 10' from above the photoresist 6. The etching component 10' is a general wet etching solution, etc. Finally, as shown in Figure 25(c), the photoresist 6 is removed to obtain a protrusion having the desired curved side surface.

[0043] Figure 26 shows a method for manufacturing a first protrusion 7 having an uneven shape on its side surface. First, as shown in Figure 26(a), a photoresist 6 is formed on the surface of the first substrate 1, and the desired resist pattern shape is obtained by exposure, development, etc. Next, as shown in Figure 26(b), the first substrate 1 is processed by applying an etching component 10'' from above the photoresist 6. The etching component 10'' uses the Bosch process, and the resulting scallop shape is used as the unevenness on the side surface. Finally, as shown in Figure 26(c), the photoresist 6 is removed to obtain a protrusion having the desired uneven shape on its side surface.

[0044] Figure 27 shows an alternative manufacturing method for the first protrusion 7, which has a rectangular cross-section. First, as shown in Figure 27(a), a processing member 12 is formed on the surface of the first substrate 1. The processing member 12 is the part that will later become the protrusion, and can be made of a metal film, resin, or other materials. Next, as shown in Figure 27(b), a photoresist 6 is formed on the surface of the first substrate 1, and the desired resist pattern shape is obtained by exposure, development, etc. Next, as shown in Figure 27(c), the first substrate 1 is processed by applying an etching component 10 from above the photoresist 6. The etching component 10 is a general dry etching gas, and can be selected depending on the type of processing member 12. Finally, as shown in Figure 27(d), the desired rectangular protrusion is obtained by removing the photoresist 6.

[0045] Figure 28 shows a method for manufacturing a recess 9 with a rectangular cross-section. First, as shown in Figure 28(a), a photoresist 6 is formed on the surface of the first substrate 1, and the desired resist pattern shape is obtained by exposure, development, etc. Next, as shown in Figure 28(b), the first substrate 1 is processed by applying an etching component 10 from above the photoresist 6. The etching component 10 is a general dry etching gas, wet etching solution, etc. Finally, as shown in Figure 28(c), the desired rectangular recess 9 is obtained by removing the photoresist 6.

[0046] Figure 29 shows the manufacturing method for a trapezoidal recess 9. First, as shown in Figure 29(a), a photoresist 6 is formed on the surface of the first substrate 1, and the desired resist pattern shape is obtained by exposure, development, etc. At this time, in order to give the resist pattern itself a taper, a gradient mask or the like is used to form a sloped resist pattern. Next, as shown in Figure 29(b), the first substrate 1 is processed by applying an etching component 10 from above the photoresist 6. By etching through the sloped resist pattern, the shape of the recessed structure also becomes a tapered shape. The etching component 10 is a general dry etching gas or a wet etching solution, etc. Finally, as shown in Figure 29(c), the desired trapezoidal recess 9 is obtained by removing the photoresist 6.

[0047] Figure 30 shows an alternative manufacturing method for a recess 9 with a rectangular cross-section. First, as shown in Figure 30(a), a processing member 12 is formed on the surface of the first substrate 1. The processing member 12 is the part that will later become the recessed structure, and can be made of a metal film, resin, or other material. Next, as shown in Figure 30(b), a photoresist 6 is formed on the surface of the first substrate 1, and the desired resist pattern shape is obtained by exposure, development, etc. Next, as shown in Figure 30(c), the first substrate 1 is processed by applying an etching component 10 from above the photoresist 6. The etching component 10 can be a general dry etching gas or a wet etching solution, and is changed according to the material of the processing member 12. Finally, as shown in Figure 30(d), the desired rectangular recess 9 is obtained by removing the photoresist 6.

[0048] (Examples) An example of manufacturing the first embodiment is described below. First, a first substrate 1 and a second substrate 17 are prepared, each having a channel 4 processed on a silicon substrate. Next, a first protrusion 7 with a height of 3 μm is obtained by resist patterning or etching at a desired position on the bonding surface of the first substrate 1. Next, a second protrusion 8 with a height of 3 μm is obtained by resist patterning or etching at a desired position on the bonding surface of the element substrate. Adhesive 3 is directly drawn onto the bonding surface of the first substrate 1 to a height of 5.5 μm. After that, the first substrate 1 and the second substrate 17 are bonded using a bonding device. At this time, the height of the adhesive layer 11 is 5 μm. After that, the entire channel member is heat-treated at 200°C for 1 hour to obtain the desired channel member bonded with an adhesive layer without communicating voids 5.

[0049] The shape shown in this embodiment is just one example, and configurations obtained by combining the shapes shown in the embodiment are also included as part of the present invention. Furthermore, although an example of joining substrates with adhesive is shown, it can also be applied to similar applications, such as when bonding chips and chip units with a encapsulant. [Explanation of Symbols]

[0050] 1. First substrate 3. Adhesive 7. First convex part 8. Second convex part 17. Second circuit board 23. The first side 24. The second side

Claims

1. a first substrate having a first surface; a second substrate having a second surface opposite to the first surface; Equipped with In a liquid ejection head in which the first substrate and the second substrate are bonded together via an adhesive between the first surface and the second surface, a first protrusion protruding toward the second surface is formed on the first surface; a second protrusion protruding toward the first surface is formed on the second surface, A liquid ejection head, wherein the first convex portion and the second convex portion are arranged apart from each other when viewed from a direction perpendicular to the first surface.

2. The liquid ejection head according to claim 1 , wherein the sum of the height of the first convex portion from the first surface and the height of the second convex portion from the second surface is equal to or greater than the thickness of the adhesive.

3. The liquid ejection head according to claim 1 , wherein the first convex portion and the second convex portion have curved side surfaces.

4. 4. The liquid ejection head according to claim 1, wherein the height of the first convex portion from the first surface and the height of the second convex portion from the second surface are different.

5. The liquid ejection head according to claim 1 , wherein the side surfaces of the first convex portion and the second convex portion have an uneven shape.

6. 2. The liquid ejection head according to claim 1, wherein the cross-sectional shapes of the first convex portion and the second convex portion are trapezoidal.

7. 2. The liquid ejection head according to claim 1, wherein the cross-sectional shapes of the first convex portion and the second convex portion are triangular.

8. openings of flow channels are formed in the first substrate and the second substrate; The liquid ejection head according to claim 1 , wherein the first convex portion and the second convex portion surround the opening.

9. The liquid ejection head according to claim 8 , wherein the first convex portion and the second convex portion continuously surround the opening.

10. The liquid ejection head according to claim 8 , wherein the first convex portion and the second convex portion intermittently surround the opening.

11. 11. The liquid ejection head according to claim 1, wherein a groove for accommodating the adhesive is formed in at least one of the first substrate and the second substrate.

12. The liquid ejection head according to claim 11 , wherein the first convex portion and the second convex portion are formed along the groove.

13. A liquid ejection head as described in Claim 8, wherein a plurality of the first convex portions and the second convex portions are formed corresponding to one of the openings.

14. a first substrate having a first surface; a second substrate having a second surface opposite to the first surface; Equipped with In a liquid ejection head in which the first substrate and the second substrate are bonded together via an adhesive between the first surface and the second surface, a protrusion protruding toward the second surface is formed on the first surface, a recess is formed on the second surface at a position facing the protrusion, A liquid ejection head characterized in that a part of the convex portion is inserted into the concave portion.

15. The liquid ejection head according to claim 14, wherein the width of the recessed portion is greater than the width of the protruding portion.

16. 16. A liquid ejection head according to claim 14, wherein the cross-sectional shapes of the convex portions and the concave portions are trapezoidal.

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