Patent Application
20250196499
The present disclosure relates to a liquid discharge head and a manufacturing method thereof.
In a liquid discharge head which generates pressure fluctuation in a pressure generation chamber filled with a liquid and discharges the liquid from a nozzle, for the purpose of avoiding propagation of the pressure fluctuation to another adjacent pressure generation chamber and causing deterioration of discharge controllability, such a head configuration is known that a unit member called a damper for suppressing the pressure fluctuation is disposed in a liquid flow-passage. Japanese Patent No. 7131260 discloses such a configuration that, in a configuration in which the damper is joined to a substrate by using an adhesive, prevents adhesion of the protruding adhesive to the damper by disposing the member on a joint portion and suppresses variation in a fluctuation suppressing effect.
When the damper is to be joined to the substrate by using an adhesive, heat treatment for hardening the adhesive is needed. At this heat treatment, due to a difference in linear expansion between the damper and a peripheral member such as the substrate, the damper is warped (curved) to an adjacent fluctuation-suppressing space side in some cases. When the damper is joined to the substrate in the warped state, a deformation amount of the damper is limited at generation of the pressure fluctuation and thus, the fluctuation-suppressing effect itself is lowered, a damper performance is not sufficiently exerted, and there is a concern that the discharge controllability is deteriorated.
In order to solve the aforementioned problem, the present disclosure has an object to provide a liquid discharge head that suppresses deterioration of the discharge controllability.
In order to achieve the object described above, a liquid discharge head according to the present disclosure includes:
Furthermore, in order to achieve the object described above, manufacturing method of a liquid discharge head, the liquid discharge head including a nozzle from which a liquid is discharged, pressure generator that generates a pressure for discharging the liquid from the nozzle, a pressure chamber in which the pressure generator is formed inside, a liquid flow-passage communicating with the nozzle, a space formed adjacently to the liquid flow-passage and separated from the liquid flow-passage, a base body constituting a wall part forming the liquid flow-passage and a wall part forming the space, a flexible member made of a resin, which is fixed to the base body, separates the liquid flow-passage and the space from each other and is warped in accordance with pressure fluctuation generated in the pressure chamber, and an inorganic film provided on a surface of the flexible member, the manufacturing method includes:
According to the present disclosure, a liquid discharge head that suppresses deterioration of the discharge controllability can be provided.
Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Hereinafter, a description will be given, with reference to the drawings, of various exemplary embodiments (examples), features, and aspects of the present disclosure. However, the sizes, materials, shapes, their relative arrangements, or the like of constituents described in the embodiments may be appropriately changed according to the configurations, various conditions, or the like of apparatuses to which the disclosure is applied. Therefore, the sizes, materials, shapes, their relative arrangements, or the like of the constituents described in the embodiments do not intend to limit the scope of the disclosure to the following embodiments.
By using
The liquid flow-passage 11 is constituted by elements such as a pressure chamber 3 including pressure generator 4, an individual supply port 8, a common flow-passage 9, a liquid supply port 10 and the like, and disposition spots, dimensions, paths and the like thereof can take various constitutions in accordance with a manufacturing method or a required discharge performance. For example, it is possible to have such a path of the liquid flow-passage that a liquid supplied from outside the substrate for liquid discharge head is transported to the vicinity of the nozzle, and the liquid that has not been discharged is returned to the outside again can be acquired. In the middle of the liquid flow-passage 11, a flexible member 6 that suppresses pressure fluctuation is formed together with an adjacent space 7.
For the pressure generator 4, a vibrating plate in which piezoelectric elements are laminated, a heat element and the like can be used, for example. The pressure generator 4 is formed in the pressure chamber 3 and generates a pressure for discharging a liquid such as ink from the nozzle 2.
The individual supply port 8 is coupled to the pressure chamber 3, which is individually controlled, but there may be such a configuration that a plurality of the individual supply ports 8 are coupled to one unit of the pressure chamber 3 or to the contrary, a configuration that one unit of the individual supply port 8 is coupled to a plurality of the pressure chambers 3.
The common flow-passage 9 is connected to a plurality of the individual supply ports 8 and functions as a reservoir for distributing a liquid.
The flexible member 6 is provided in the middle of the liquid flow-passage 11, forms a part of a side wall of the liquid flow-passage 11 and is formed so as to contact the liquid. Adjacently to the flexible member 6, a space 7 to be a space for displacement is provided, and the liquid does not flow therein. The flexible member 6 has a part other than a fixed portion warped in accordance with the pressure fluctuation generated in the pressure chamber 3. The flexible member 6 is a member for absorbing the pressure fluctuation generated in the pressure chamber 3 by its flexibility, suppressing pressure propagation to the pressure chamber 3 in the vicinity and making a discharge performance stable. Such a configuration is possible for the space 7 that an atmospheric communication port is provided so that the inside is brought into a vacuum state, and displacement of the flexible member 6 is not limited.
For the flexible member 6, a film of various materials having flexibility such as an organic film, an inorganic film, a metal film and the like can be applied, but preferably, an organic resin film having both flexibility and resistance against a liquid is used. As the organic resin film that can be applied to the flexible member 6, polyimide, polyamide, polyphenylene sulfide and the like can be cited. A thickness of the flexible member 6 may be set appropriately with an elastic modulus as a reference by considering viscosity and density of the liquid suppressing the pressure fluctuation, a discharge frequency of the liquid, a distance to the pressure chamber 3 and the like. In general, for an application as the substrate 1 for liquid discharge head, the thickness of the flexible member 6 is formed within a range from submicron to approximately several tens of microns.
With reference to
Subsequently, a constitution and a manufacturing method of the compliance substrate 50, which is a constituent element of the substrate 1 for liquid discharge head, will be explained separately for a Comparative Example and a plurality of Embodiments according to the present disclosure. First, the Comparative Example will be explained and then, First to Ninth Embodiments will be explained. In the explanation of the constitution of each of the Embodiments, the same signs are given to the constitutions similar to the previously explained Embodiments, and the explanation will be omitted.
With reference to
After the application of the adhesive 61 on the base substrate 51, then, the film-state flexible member 6 is bonded onto the base substrate 51 by roller pressurization or the like. After that, the heat treatment (curing) is performed so as to harden the adhesive 61 and to fix the flexible member 6 to the base substrate 51. A temperature of the heat treatment differs in accordance with the material of the adhesive or a heat-resistant temperature of the flexible member 6, but polymerization of adhesive molecules is promoted by heating at several hundred degrees, for example, for hardening. Through the fixing process of the flexible member 6, the space 7 becomes a space surrounded and closed by the flexible member 6 and the base substrate 51. In addition, an opening on the adhesive surface 51a side of the liquid supply port 10 is closed by the flexible member 6.
In the compliance substrate 50 manufactured as above, there is such a case that the flexible member 6 is formed in a warped state so as to be convex toward the space 7 side.
In a laminated body of different kinds of materials, whose heat expansion coefficients are different, stress causing a curve so as to become convex toward a side of the material whose heat expansion coefficient is smaller is generated in general. Therefore, when a silicon substrate is used for the base substrate 51, and an organic resin for the flexible member 6, for example, there is a relation in the heat expansion coefficient as the heat expansion coefficient of the flexible member>the heat expansion coefficient of the silicon substrate in general. In such a case, the flexible member 6 is curved and warped so as to be convex toward the space 7 side. If the substrate 1 for liquid discharge head is fabricated in the state in which the flexible member 6 is warped as above, displacement of the flexible member 6 to the space 7 side is limited at the absorption of the pressure fluctuation, and the suppression function is also limited. Therefore, in the configuration of the Comparative Example, when the pressure fluctuation is generated in the common flow-passage 9 in the pressure generation chamber, there is a concern that the pressure fluctuation propagates to another common flow-passage 9 or the like and discharge controllability of the substrate 1 for liquid discharge head is deteriorated.
Subsequently, with reference to
In order to reduce (correct) warping of the flexible member 6 warped toward the space 7 side, in the First Embodiment, a material with a heat expansion coefficient smaller than that of the flexible member 6 to be the base is used for the surface member 5. Internal stress of the thin film is different depending on a composition and a thickness and is also different depending on a film-forming method and a film-forming condition such as a pressure and the like and thus, it is preferable that the film-forming method, the film-forming condition and the like of the surface member are selected so that stress in an appropriate direction can be obtained. In general, in the case of the metal thin film, it is known that the sputter method, the ion-plating method and the like indicate compression stress, while deposition, the Chemical Vapor Deposition (CVD) method and the like indicate tensile stress.
As shown in
As shown in
Subsequently, with reference to
The surface member 5 according to the Second Embodiment is a film-state member constituted by a first surface layer 52 in contact with the flexible member 6 and a second surface layer 53 formed on the first surface layer 52 and in contact with the liquid in the liquid flow-passage 11. The first surface layer 52 is specialized in a function of reducing warping of the flexible member 6 by its internal stress and is a layer adjacent to the space 7. The second surface layer 53 is specialized in a protective film function, is a layer adjacent to the liquid flow-passage 11, and includes a component different from that of the first surface layer 52. As described above, by having the surface member 5 in a two-layer constitution, the function required for the surface member 5 can be controlled separately for each layer, and such a design to maximize an effect of the surface member 5 can be made. For example, by forming the first surface layer 52 by tantalum oxide and by forming the second surface layer 53 by silicon carbide, the function of reducing warping and the protective-film function of the surface member 5 can be maximized. As described above, by constituting the surface member 5 by a plurality of layers, deterioration in the discharge controllability of the substrate 1 for liquid discharge head can be suppressed more effectively.
Note that the above-described constitution is only an example, and the present disclosure is not limited to the above-described constitution. For example, it is possible to have a three-layer constitution in which an intermediate layer for improving close contact is provided between the first surface layer 52 and the second surface layer 53 or a constitution of four layers or more.
Subsequently, with reference to
When the surface member 5 is formed by selecting the film-forming method with favorable deposition properties also on an inside of a three-dimensional structure such as the ALD method, the surface on the flexible member 6 side and the other surface of the compliance substrate 50 have the same degree of thickness as in the Second Embodiment. However, since the internal stress of the thin film is different depending on the base, if bases are formed by different materials for the front and the rear of the substrate, when the surface member 5 is formed with an entirely uniform thickness, a curve of the entire substrate might be changed. Thus, the surface member 5 according to the Third Embodiment has different layer thicknesses between the first surface-layer upper part 52a and the first surface-layer lower part 52b and is constituted such that the layer thickness is different between a second surface-layer upper part 53a and a second surface-layer lower part 53b. As described above, according to the constitution in which the thickness of the surface member 5 is made different between the flexible member 6 side and the opposite side thereof, a balance in the stress generated in each surface can be controlled. Thus, the curve of the entire compliance substrate 50 can be controlled, and the deterioration in the discharge controllability of the substrate 1 for liquid discharge head can be suppressed.
Subsequently, with reference to
The surface member 5 does not have to be formed continuously in a series in a planar direction of the flexible member 6. One of merits when the surface members 5 are patterned in the planar direction and formed in plural discontinuously is that, if film peeling of the surface member 5 occurs at some spot, the film peeling would not occur in succession in the surroundings from that spot as a start point but can be retained to local film peeling. As shown in
Subsequently, with reference to
As in the constitution of the Fifth Embodiment, by having a pattern in which the surface member 5 formed only at a warped part of the flexible member 6 is further divided in the planar direction, resistance against the film peeling is further improved. In addition, the suppression effect of the pressure fluctuation can be stably obtained even in the head drive for a long time, the deterioration in the discharge controllability of the substrate 1 for liquid discharge head can be suppressed for a long time.
Subsequently, with reference to
As in the constitution of the Sixth Embodiment, not by forming the surface member 5 at a spot where the flexible member 6 in contact with the space 7 is warped but by forming the surface member 5 in an area other than that, the warping can be also reduced indirectly. The constitution as above is preferable because such a concern is eliminated that the surface member 5 is not directly formed at an active part where the pressure fluctuation of the flexible member 6 is absorbed and thus, there is no more concern that the flexibility is hindered, and there is no concern of performance change caused by the film peeling, either. The reasons why the warping can be reduced by indirect film-forming of the surface member 5 are as follows. As already described, the warping emerges with the stress caused by a difference between heat expansion and contraction between the flexible member 6 and the base substrate 51 as a cause. The entire substrate is curved by the stress, while the flexible member 6 at a part tented in the space 7 (covering the space 7) is not supported by the base of the base substrate 51, it is warped at the spot and alleviates the stress. That is, the total stress is distributed to the curve and the warping of the substrate, and if the curve of the substrate can be made smaller, the warping can be also reduced as a result. Therefore, by the film-forming of the surface member 5 in the area other than the warping spot so as to reduce the curve of the substrate, the warping of the flexible member 6 can be indirectly reduced.
Subsequently, with reference to
As shown in
As shown in
By going through the processes as above, the surface member 5 as shown in
Subsequently, with reference to
The flow-passage substrate 40, the pressure-generation substrate 30, the nozzle substrate 20 are laminated in this order by joining, respectively. The joining can be performed regardless of the form of the substrate such as a wafer form, a chip form or the like, and the joining can be performed by a method of directly joining the substrate surfaces to each other, the joining via the adhesive layer such as a metal film, an organic resin, an inorganic film or the like.
By using the manufacturing method as above, it becomes possible for the surface member 5 to cover the surface of the flexible member 6 and the entire surface of the nozzle 2, the pressure chamber 3, the liquid flow-passage (the individual supply port 8 and the common flow-passage 9) and the like constituting the substrate 1 for liquid discharge head, that is, the path of the liquid including the liquid flow-passages (the individual supply port 8 and the common flow-passage 9), the pressure chamber 3, and the nozzle 2 can be continuously covered in a lump-sum. As a result, all the parts in contact with the liquid including a joining interface between the substrates and the adhesive layer can be covered by the surface member 5, and protection against the liquid can be improved. By forming the surface member 5 for the entire substrate 1 for liquid discharge head as above, reduction in the warping of the flexible member 6 and the protection of the substrate 1 for liquid discharge head against the liquid can be performed at the same time, and a manufacturing cost can be reduced. A film-forming method of the surface member 5 in this case is not limited, but in the substrate 1 for liquid discharge head in which the liquid flow-passage, the nozzle, the pressure chamber and the like are disposed in a complicated manner, a method such as the ALD method, for example, which is excellent in conformal film-forming into an inside of a three-dimensional structure can be suitably used.
With reference to
In this Embodiment, as an example, the flow-passage substrate 40 and the pressure-generation substrate 30 are formed of a silicon substrate, and the base substrate 51 is formed of stainless steel (SUS). The present disclosure can be suitably used even for the liquid discharge head using the substrate for liquid discharge head having the lamination configuration as in
Subsequently, for some of the above-described Embodiments, the constitution of the substrate 1 for liquid discharge head, which was actually manufactured, and a discharge evaluation using the substrate 1 for liquid discharge head will be explained.
An Example 1 will be explained with reference to
In the Example 1, a silicon substrate was used for the base substrate 51 of the compliance substrate 50, a polyimide film was used as the flexible member 6, and a titanium oxide thin-film was used for the surface member 5. In the Example 1, the heat expansion coefficient of the base substrate 51, which is a silicon substrate, is approximately less than 5 ppm/K, and the heat expansion coefficient of the flexible member 6, which is a polyimide film, is approximately 10 to 50 ppm/K. In addition, the heat expansion coefficient of the surface member 5, which is a titanium oxide thin-film, is approximately 10 ppm/K.
In fabrication of the substrate 1 for liquid discharge head according to the Example 1, first, a resist pattern was drawn on the silicon substrate by the photolithography and then, the space 7 and the liquid supply port 10 were formed by performing the dry etching so as to fabricate the base substrate 51. Subsequently, an adhesive with an organic resin as a major component was applied to the adhesive surface 51a of the base substrate 51 in which the space 7 was formed, and the polyimide film with the thickness of 3 μm was bonded to the adhesive surface 51a. Subsequently, the heat treatment at 200° C. was performed so as to harden the adhesive, and the polyimide film was fixed to the base substrate 51. After the fixation, the polyimide film was warped to the space 7 side by approximately 2 μm.
After the polyimide film, which is the flexible member 6, was bonded to the base substrate 51, in order to remove the polyimide film on a part corresponding to the liquid supply port 10, pattern formation by the photoresist and the etching treatment were performed, and the liquid supply port 10 was made to penetrate. Subsequently, 100 nm of the titanium oxide thin-film was formed by the ALD method as the surface member 5, and the compliance substrate 50 was fabricated. In this state, the warping of the polyimide film toward the space 7 side was approximately 0.3 μm, which was reduced with respect to the warping of 2 μm after the fixation. The substrate 1 for liquid discharge head was fabricated by joining the compliance substrate 50 fabricated as above with the separately prepared nozzle substrate 20, the pressure-generation substrate 30, and the flow-passage substrate 40.
The manufacturing method of the substrate 1 for liquid discharge head according to the Comparative Example is similar to the Example 1 except the point that the surface member 5 is not formed. Therefore, as shown in
The discharge evaluation was made by using the substrate 1 for liquid discharge head in the Example 1 fabricated as above and the substrate 1 for liquid discharge head in the Comparative Example. In the discharge evaluation, the liquid discharge was performed by using the respective substrates 1 for liquid discharge head, and the behaviors were observed. In the substrate 1 for liquid discharge head according to the Comparative Example, changes in a flying speed and a volume of the liquid considered to be a crosstalk occurred between the nozzles 2 adjacent to each other. On the other hand, in the substrate 1 for liquid discharge head according to the Example 1, the crosstalk did not occur under the same driving condition, and improvement in the suppression effect of the pressure fluctuation by the flexible member 6 was observed.
With reference to
In fabrication of the substrate 1 for liquid discharge head according to the Example 2, first, similarly to the Example 1, the compliance substrate 50 is fabricated. Subsequently, a dry film resist was bonded on a surface on the polyimide film side, a resist pattern was drawn by the photolithography and then, wet etching was performed so as to pattern a titanium oxide thin-film. The pattern was made a strip form, and the titanium oxide thin-film was formed within a region of the polyimide film at a position overlapping the space 7 when the compliance substrate 50 is viewed on a plan view. Through these processes, the titanium oxide thin-film is formed so that the plurality of surface members 5 are aligned at intervals in a direction parallel to the adhesive surface 51a of the base substrate 51. In this state, the warping of the polyimide film toward the space 7 side was approximately 0.5 μm, which was reduced with respect to the warping of 2 μm after the fixation.
The discharge evaluation was made similarly to the Example 1 by using the substrate 1 for liquid discharge head in the Example 2 fabricated as above. In the substrate 1 for liquid discharge head of the Example 2, too, a crosstalk did not occur similarly to the Example 1, and improvement in the suppression effect of the pressure fluctuation was observed. In addition, even in continuous discharge for a long time, discharge variation among the nozzles is small, and the effect of suppressing the film peeling of the titanium oxide thin-film, which is the surface member 5, can be obtained.
With reference to
In the Example 3, a silicon substrate was used for the base substrate 51 of the compliance substrate 50, a polyimide film was used as the flexible member 6, and a polyurethane resin was used for the surface member 5. In the Example 3, the heat expansion coefficient of the base substrate 51, which is a silicon substrate, is approximately less than 5 ppm/K, and the heat expansion coefficient of the flexible member 6, which is a polyimide film, is approximately 10 to 50 ppm/K. In addition, the heat expansion coefficient of the surface member 5, which is a titanium oxide thin-film, is approximately 100 to 200 ppm/K.
In the fabrication of the substrate 1 for liquid discharge head according to the Example 3, first, a resist pattern was drawn on the silicon substrate by the photolithography and then, dry etching was performed so as to form the space 7, the liquid supply port 10, and the atmospheric communication port 12, and the base substrate 51 was fabricated. Subsequently, on the adhesive surface 51a of the base substrate 51 on which the space 7 was formed, the adhesive with an organic resin as a major component was applied, and a polyimide film with a thickness of 3 μm was bonded on the adhesive surface 51a. Subsequently, the heat treatment at 200° C. was performed so as to harden the adhesive, and the polyimide film was fixed to the base substrate 51. After the fixation, the polyimide film was warped toward the space 7 side by approximately 1 μm.
After the polyimide film, which is the flexible member 6, was bonded to the base substrate 51, in order to remove the polyimide film on a part corresponding to the liquid supply port 10, the pattern formation by the photoresist and the etching treatment were performed, and the liquid supply port 10 was made to penetrate. Subsequently, the polyurethane resin was formed into a film of 1 μm on the surface of the space 7 side of the polyimide film from the atmospheric communication port 12 side by the vapor deposition polymerization method as the surface member 5 so as to fabricate the compliance substrate 50. In this state, the warping of the polyimide film toward the space 7 side was approximately 0.2 μm, which was reduced with respect to the warping of 1 μm after the fixation.
The discharge evaluation was made similarly to the Example 1 by using the substrate 1 for liquid discharge head in the Example 3 fabricated as above. In the substrate 1 for liquid discharge head according to the Example 3, too, a crosstalk did not occur as in the Example 1, and the effect to suppress the pressure fluctuation was improved.
With reference to
In the Example 4, the space 7 is formed on the side of a surface on which the nozzle 2 is formed in the substrate 1 for liquid discharge head, and a positional relation with the flexible member 6 in a sectional direction of the substrate 1 for liquid discharge head is configured to be different from the Examples 1 to 3. In addition, the substrate 1 for liquid discharge head according to the Example 4 is constituted by the nozzle substrate 20, the compliance substrate 50, the pressure-generation substrate 30, and the flow-passage substrate 40 aligned in this order.
In the fabrication of the substrate 1 for liquid discharge head according to the Example 4, first, the base substrate 51 was fabricated similarly to the Example 1, the flexible member 6 such as a polyimide film was bonded and then, patterning was performed. As a result, the compliance substrate 50 before film formation of the surface member 5 is performed was fabricated. Subsequently, the pressure-generation substrate 30, the flow-passage substrate 40, and the nozzle substrate 20 prepared separately were joined sequentially so as to form the substrate 1 for liquid discharge head before the film formation of the surface member 5. Lastly, by film formation of the surface member 5, the substrate 1 for liquid discharge head having the schematic sectional diagram shown in
The discharge evaluation was made similarly to the Example 1 by using the substrate 1 for liquid discharge head in the Example 4 fabricated as above. In the substrate 1 for liquid discharge head according to the Example 4, too, a crosstalk did not occur as in the Example 1, and the effect to suppress the pressure fluctuation was improved. In addition, the substrate 1 for liquid discharge head was immersed in a liquid, and a heat-cycle test (0.15 MPa, 120° C., 30 cycles) was executed under pressurization, but peeling of the substrate or large dissolution inside the flow passage was not confirmed, but it was found out that an effect of improving protection of the surface member 5 continuously wrapping the substrate 1 for liquid discharge head was high.
Note that, each of the above-described Embodiments has a configuration on the premise that the flexible member 6 is warped toward the space 7 side, but the present disclosure can be applied also to such a configuration that the flexible member 6 is warped toward the liquid flow-passage 11 side. For example, when an inorganic film or a metal film with a heat expansion coefficient smaller than that of the organic resin is used for the flexible member 6, and an amorphous substrate such as an organic resin substrate, a glass substrate or the like with a large heat expansion coefficient is used for the base substrate 51, the heat expansion coefficient of the flexible member 6 can be smaller than that of the base substrate 51. When the heat expansion coefficient of the flexible member 6 is smaller than that of the base substrate 51, there is a possibility that the flexible member 6 is warped toward the liquid flow-passage 11 side after the heat treatment of the adhesive 61. In such cases, the surface member 5 with the heat expansion coefficient larger than that of the flexible member 6 is provided on the surface on the liquid flow-passage 11 side of the flexible member 6, or the surface member 5 with the heat expansion coefficient smaller than that of the flexible member 6 is provided on the surface on the space 7 side of the flexible member 6 so that the warping of the flexible member 6 can be reduced.
In addition, the configuration of each of the Embodiments described above can be combined as appropriate. For example, as in the First Embodiment, a plurality of the surface members 5 may be aligned and formed as in the Fourth Embodiment or the Fifth Embodiment on the whole surface on the liquid flow-passage 11 side of the flexible member 6. In addition, for example, as in the Second Embodiment or the Third Embodiment, the surface member 5 constituted by a plurality of layers may be formed on the surface on the space 7 side of the flexible member 6 as in the Seventh Embodiment.
While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the disclosure is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2023-210990, filed on Dec. 14, 2023 and Japanese Patent Application No. 2024-167211, filed on Sep. 26, 2024, which are hereby incorporated by reference herein in their entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-210990 | Dec 2023 | JP | national |
| 2024-167211 | Sep 2024 | JP | national |
