filter

Abstract

A filter according to the present invention includes a first principal surface and a second principal surface opposite to the first principal surface, and further includes a filter substrate portion including a plurality of through-holes which are formed therein and make the first principal surface and the second principal surface in communication with each other. The filter substrate portion includes one or more curved portions warped toward the first principal surface or the second principal surface.

Description

[Technical Field]

[0001] The present invention relates to a filter. [Background technology]

[0002] For example, Patent Document 1 discloses a cell-trapping metal filter as a filter for trapping cells. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-188323 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the filter described in Patent Document 1 still has room for improvement in terms of improving usability.

[0005] An object of the present invention is to provide a filter that can improve usability. [Means for solving the problem]

[0006] The filter of one aspect of the present invention comprises: a filter base portion having a first main surface and a second main surface opposite to the first main surface, and having a plurality of through holes formed therein that communicate between the first main surface and the second main surface; The filter base has one or more curved portions that are warped toward the first main surface side or the second main surface side. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a filter that can improve usability. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view of an example of a filter according to a first embodiment of the present invention, viewed from a first main surface side. [Figure 2] 2 is a perspective view of an example of the filter according to the first embodiment of the present invention, viewed from the second main surface side. FIG. [Figure 3] 1 is a front view of an example of a filter according to a first embodiment of the present invention. [Figure 4] FIG. 2 is a rear view of an example of the filter according to the first embodiment of the present invention. [Figure 5] 1 is a left side view of an example of a filter according to a first embodiment of the present invention. [Figure 6] 1 is a right side view of an example of a filter according to a first embodiment of the present invention. [Figure 7] 1 is a plan view of an example of a filter according to a first embodiment of the present invention. [Figure 8] FIG. 2 is a bottom view of an example of the filter according to the first embodiment of the present invention. [Figure 9] FIG. 4 is an enlarged view of a part of the filter portion. [Figure 10] FIG. 4 is an enlarged view of a part of a reinforcing portion in a filter portion. [Figure 11] 11 is a cross-sectional view of the filter portion of FIG. 10 taken along line AA. [Figure 12] FIG. [Figure 13] FIG. [Figure 14A] 3A to 3C are schematic diagrams illustrating an example of steps in a method for manufacturing a filter. [Figure 14B] 3A to 3C are schematic diagrams illustrating an example of steps in a method for manufacturing a filter. [Figure 14C] 3A to 3C are schematic diagrams illustrating an example of steps in a method for manufacturing a filter. [Figure 14D] 3A to 3C are schematic diagrams illustrating an example of steps in a method for manufacturing a filter. [Figure 14E] 3A to 3C are schematic diagrams illustrating an example of steps in a method for manufacturing a filter. [Figure 14F] 3A to 3C are schematic diagrams illustrating an example of steps in a method for manufacturing a filter. [Figure 14G] 3A to 3C are schematic diagrams illustrating an example of steps in a method for manufacturing a filter. [Figure 14H] 3A to 3C are schematic diagrams illustrating an example of steps in a method for manufacturing a filter. [Figure 15] 10 is a table showing experimental results of measuring the amount of warpage using current density as a parameter. [Figure 16] FIG. 10 is a perspective view of a filter of a modified example, viewed from the first main surface side. [Figure 17] FIG. 10 is a perspective view of a filter of a modified example, viewed from the second main surface side. [Figure 18] FIG. 10 is a front view of a modified filter. [Figure 19] FIG. 10 is a rear view of a modified filter. [Figure 20] FIG. 10 is a left side view of a modified filter. [Figure 21] FIG. 10 is a right side view of a modified filter. [Figure 22] FIG. 10 is a plan view of a modified filter. [Figure 23] FIG. 10 is a bottom view of a modified filter. DETAILED DESCRIPTION OF THE INVENTION

[0009] (Background to the invention) The filter described in Patent Document 1 is formed in the shape of a flat plate, which means that the filter does not have a handle, making it difficult to handle.

[0010] For example, when removing a filter from a holder after filtration is complete, a user holds the outer periphery of the filter with tweezers or the like and lifts it up. With a flat, plate-shaped filter, it is difficult to insert the tips of the tweezers into the outer periphery of the filter, making it difficult to lift the filter. Furthermore, when holding and lifting a filter with tweezers, force is applied to the outer periphery of the filter when the tips of the tweezers come into contact with the outer periphery of the filter, which can damage the filter.

[0011] Furthermore, with flat, plate-shaped filters, it is difficult to distinguish between the front and back.

[0012] Therefore, in order to solve these problems, the present inventors discovered a configuration in which a filter is provided with a warp, and arrived at the following invention.

[0013] The filter of one aspect of the present invention comprises: a filter base portion having a first main surface and a second main surface opposite to the first main surface, and having a plurality of through holes formed therein that communicate between the first main surface and the second main surface; The filter base has one or more curved portions that are warped toward the first main surface side or the second main surface side.

[0014] Such a configuration can improve usability.

[0015] The filter may further include a frame portion that surrounds the periphery of the filter base portion and conforms to the outer peripheral shape of the filter base portion.

[0016] With this configuration, the mechanical strength of the filter is improved and the curved portion can be easily formed.

[0017] The filter may further include a reinforcing portion provided on the filter base portion and having a thickness greater than that of the filter base portion.

[0018] Such a configuration can improve the mechanical strength of the filter.

[0019] When viewed from the first main surface side of the filter base, the reinforcing portion has a plurality of first reinforcing members extending in a first direction and a plurality of second reinforcing members extending in a second direction intersecting the first direction, When viewed from the first main surface side of the filter base portion, the one or more curved portions may be warped toward the first main surface side or the second main surface side in a third direction that intersects the first direction and the second direction.

[0020] With this configuration, the direction of warping of the curved portion can be controlled by the shape of the reinforcing portion.

[0021] The amount of warping of the one or more curved portions is 4×10 of the outer diameter of the filter. -4 It may be 0.1 times or more and 0.1 times or less.

[0022] Such a configuration can further improve usability.

[0023] the filter base has a flat portion at the center of the filter base where the first main surface and the second main surface are formed flat, The plurality of curved portions may be formed with the flat portion sandwiched therebetween in cross section.

[0024] Such a configuration can further improve usability.

[0025] The proportion of the area of ​​the first main surface occupied by the one or more curved portions may be 1% or more and 100% or less.

[0026] Such a configuration can further improve usability.

[0027] The filter may be mainly composed of at least one of a metal and a metal oxide.

[0028] This configuration improves the mechanical strength and ease of use.

[0029] Hereinafter, a first embodiment of the present invention will be described with reference to the accompanying drawings. In each drawing, each element is shown exaggerated for ease of explanation.

[0030] (Embodiment 1) [Overall configuration] FIG. 1 is a perspective view of an example of filter 1 according to a first embodiment of the present invention, as viewed from the first principal surface PS1 side. FIG. 2 is a perspective view of an example of filter 1 according to a first embodiment of the present invention, as viewed from the second principal surface PS2 side. FIG. 3 is a front view of an example of filter 1 according to a first embodiment of the present invention. FIG. 4 is a rear view of an example of filter 1 according to a first embodiment of the present invention. FIG. 5 is a left side view of an example of filter 1 according to a first embodiment of the present invention. FIG. 6 is a right side view of an example of filter 1 according to a first embodiment of the present invention. FIG. 7 is a plan view of an example of filter 1 according to a first embodiment of the present invention. FIG. 8 is a bottom view of an example of filter 1 according to a first embodiment of the present invention. In the figures, the X, Y, and Z directions indicate the vertical, horizontal, and thickness directions of filter 1, respectively.

[0031] For example, the filter 1 is a filter that filters a fluid containing a substance to be filtered.

[0032] As used herein, the term "filtering target" refers to a target to be filtered among targets contained in a fluid. For example, the filtering target may be a biological substance contained in the fluid. The term "biological substance" refers to a substance derived from a living organism, such as a cell (eukaryote), a bacterium (true bacterium), or a virus. Examples of cells (eukaryotes) include induced pluripotent stem cells (iPS cells), embryonic stem cells, stem cells, mesenchymal stem cells, mononuclear cells, single cells, cell clumps, floating cells, adherent cells, nerve cells, white blood cells, cells for regenerative medicine, autologous cells, cancer cells, circulating cancer cells (CTCs), HL-60, HELA, and fungi. Examples of bacteria (true bacterium) include Escherichia coli and Mycobacterium tuberculosis.

[0033] Fluids include, for example, liquids and gases. Liquids include, for example, cell suspensions.

[0034] The filter 1 is a metal filter. The material constituting the filter 1 is primarily composed of at least one of a metal and a metal oxide. The material constituting the filter 1 may be, for example, gold, silver, copper, platinum, nickel, palladium, titanium, alloys thereof, or oxides thereof. In particular, by using titanium or a nickel-palladium alloy, metal elution is reduced, thereby reducing the impact on the object to be filtered.

[0035] As shown in FIGS. 1 to 8, the filter 1 includes a filter portion 10 and a frame portion 20 provided on the outer periphery of the filter portion 10. The filter 1 also has a first main surface PS1 and a second main surface PS2 opposite the first main surface PS1. In the first embodiment, the filter portion 10 and the frame portion 20 are integrally formed. The first main surface PS1 and the second main surface PS2 face each other.

[0036] <Filter section> The filter section 10 is a section that filters a fluid containing a substance to be filtered. The filter section 10 is composed of a filter base section 12 having a plurality of through holes 11 formed therein, the through holes 11 connecting the first main surface PS1 and the second main surface PS2.

[0037] The filter portion 10 has a flat portion 30 in which the first main surface PS1 and the second main surface PS2 are formed flat, and a plurality of curved portions 40 formed with the flat portion 30 sandwiched therebetween.

[0038] The flat portion 30 is formed in the center of the filter portion 10. Specifically, when viewed from the first main surface PS1 side, the flat portion 30 is formed from the center of the filter portion 10 along the X direction to the outer periphery of the filter 10.

[0039] In cross-sectional view, the multiple curved portions 40 are formed on part of the outer periphery of the filter 1 with the flat portion 30 sandwiched therebetween. The multiple curved portions 40 are warped toward the first main surface PS1. Specifically, the multiple curved portions 40 are curved in a direction from the second main surface PS2 toward the first main surface PS1. Furthermore, the multiple curved portions 40 have a curved shape in a free state in which no external force is applied to the filter 1. In the first embodiment, the filter section 10 is formed with two curved portions 40 facing each other in the Y direction. Therefore, as shown in FIGS. 7 and 8, a cross section of the filter 1 cut in the Y direction is formed in a substantially U-shape.

[0040] The shape of the filter section 10 is, for example, circular, polygonal, or elliptical when viewed in the thickness direction (Z direction) of the filter 1. In the first embodiment, the shape of the filter section 10 is substantially circular. In this specification, "substantially circular" means that the ratio of the length of the major axis to the length of the minor axis is 1.0 or more and 1.2 or less.

[0041] <Frame> The frame portion 20 is provided on the outer periphery of the filter portion 10, and has a smaller number of through holes 11 per unit area than the filter portion 10. The number of through holes 11 in the frame portion 20 is 1% or less of the number of through holes 11 in the filter portion 10. The thickness of the frame portion 20 may be thicker than the thickness of the filter portion 10. With this configuration, the mechanical strength of the filter 1 can be increased.

[0042] The frame portion 20 surrounds the outer periphery of the filter portion 10 and has a shape that follows the outer periphery of the filter portion 10. The frame portion 20 forms part of the flat portion 30 and parts of the multiple curved portions 40 in the outer periphery of the filter portion 10. Specifically, the frame portion 20 located at the flat portion 30 of the filter portion 10 is formed flat. The frame portion 20 located at the curved portions 40 of the filter portion 10 is curved following the shape of the curved portions 40. In other words, the frame portion 20 located at the curved portions 40 is warped toward the first main surface PS1.

[0043] When the filter 1 is used by connecting it to an apparatus, the frame 20 may function as a connection part that connects the filter 1 to the apparatus. Furthermore, the frame 20 may display information about the filter 1 (such as the dimensions of the through-hole 11).

[0044] The frame portion 20 is formed in a ring shape when viewed from the first main surface PS1 side of the filter portion 10. When the filter 1 is viewed from the first main surface PS1 side, the center of the frame portion 20 coincides with the center of the filter portion 10. In other words, the frame portion 20 is formed concentrically with the filter 1.

[0045] The filter section 10 will be described in detail below.

[0046] Fig. 9 is an enlarged perspective view of a portion of the filter unit 10. As shown in Fig. 9, a plurality of through holes 11 are periodically arranged on the first main surface PS1 and the second main surface PS2 of the filter unit 10. Specifically, the plurality of through holes 11 are provided in the filter unit 10 at equal intervals in a matrix pattern.

[0047] In the first embodiment, the plurality of through holes 11 are arranged along two arrangement directions parallel to each side of the square when viewed from the second main surface PS2 side (Z direction) of the filter portion 10. By arranging the plurality of through holes 11 in a square lattice arrangement in this way, it is possible to increase the aperture ratio and reduce the resistance of the filter 1 to the fluid. This configuration can shorten the processing time and reduce stress on the object to be filtered. Furthermore, the improved symmetry of the arrangement of the plurality of through holes 11 makes it easier to observe the filter 1.

[0048] The arrangement of the plurality of through holes 11 is not limited to a square lattice arrangement, and may be, for example, a quasi-periodic arrangement or a periodic arrangement. Examples of the periodic arrangement include a rectangular arrangement in which the intervals in the two arrangement directions are not equal, a triangular lattice arrangement, or a regular triangular lattice arrangement, as long as the arrangement is a square arrangement. The arrangement of the through holes 11 is not limited as long as a plurality of the through holes 11 are provided in the filter section 10.

[0049] In the filter section 10, a portion where the through holes 11 are not formed is formed by a filter base section 12. As shown in FIG. 9, the filter base section 12 is formed in a lattice pattern. Specifically, in the filter section 10, the filter base section 12 has a plurality of first base members 12a extending in a first direction D1 and a plurality of second base members 12b extending in a second direction D2 intersecting with the first direction D1. The first direction D1 and the second direction D2 intersect on the XY plane. The plurality of first base members 12a are arranged at equal intervals in the second direction D2. The plurality of second base members 12b are arranged at equal intervals in the first direction D1.

[0050] The plurality of first base members 12a and the plurality of second base members 12b are formed of plate-like members. The plurality of first base members 12a and the plurality of second base members 12b intersect with each other to define a plurality of through holes 11. In the first embodiment, when the filter unit 10 is viewed from the second main surface PS2 side, the first direction D1 and the second direction D2 are orthogonal to each other.

[0051] In the first embodiment, the plurality of first base members 12a and the plurality of second base members 12b are integrally formed.

[0052] The thickness of the filter base 12 in the filter unit 10 is 0.5 μm or more and 20 μm or less. This provides mechanical strength and reduces the pressure loss of the fluid passing through the filter. Preferably, the thickness of the filter base 12 in the filter unit 10 is 1.0 μm or more and 3 μm or less. This further reduces the pressure loss of the fluid passing through the filter 1.

[0053] In the first embodiment, the thickness of the filter base 12 is designed to be approximately constant. By making the thickness of the filter base 12 approximately constant, the position of the curved portion 40 and the amount of warping can be controlled with good reproducibility. "Approximately constant" means that the thickness of the filter base 12 has an error of ±5% or less. However, the thickness of the filter base 12 is not limited to being approximately constant.

[0054] The spacing b of the through holes 11 is designed appropriately depending on the material to be filtered to be separated. For example, when the material to be filtered is cells, the spacing b of the through holes 11 is designed appropriately depending on the type (size, shape, properties, elasticity) or quantity of the cells. Here, the spacing b of the through holes 11 means the distance between the center of any one through hole 11 and the center of an adjacent through hole 11 when the through holes 11 are viewed from the second main surface PS2 side of the filter section 10, as shown in FIG. 9. In the first embodiment, the through holes 11 are square when viewed from the second main surface PS2 side. The center of the through hole 11 is the intersection of two diagonals.

[0055] In the case of a periodically arranged structure, the interval b between the through-holes 11 is, for example, more than 1 time and not more than 10 times the length of one side a of the through-holes 11, and preferably not more than 3 times the length of one side a of the through-holes 11. Alternatively, for example, the aperture ratio of the filter part 10 is 10% or more, and preferably the aperture ratio is 25% or more. With such a configuration, the resistance of the filter part 10 to the fluid can be reduced. Therefore, the processing time can be shortened and stress on the cells can be reduced. The aperture ratio is calculated by (area occupied by the through-holes 11) / (projected area of ​​the second main surface PS2 when it is assumed that the through-holes 11 are not open).

[0056] In the through hole 11, an opening on the first main surface PS1 side and an opening on the second main surface PS2 side communicate with each other through a continuous wall surface. Specifically, the through hole 11 is provided so that the opening on the first main surface PS1 side can be projected onto the opening on the second main surface PS2 side. In other words, when the filter unit 10 is viewed from the second main surface PS2 side, the through hole 11 is provided so that the opening on the second main surface PS2 side overlaps with the opening on the first main surface PS1 side. In the first embodiment, the inner wall defining the through hole 11 is provided so as to be perpendicular to the first main surface PS1 and the second main surface PS2.

[0057] The through hole 11 has a square shape when viewed from the second main surface PS2 side, and the side a of the through hole 11 is 0.5 μm or more and 400 μm or less. Preferably, the side a of the through hole 11 is 1 μm or more and 30 μm or less.

[0058] The shape of the through-hole 11 is not limited to a square when viewed from the second main surface PS2 side. For example, the shape of the through-hole 11 may be a circle, an ellipse, a rectangle, a polygon, etc. when viewed from the second main surface PS2 side.

[0059] In the filter unit 10, the surface roughness of the first principal surface PS1 and the second principal surface PS2 is preferably small. Here, the surface roughness refers to the average value of the differences between the maximum and minimum values ​​measured at any five locations using a stylus-type step profiler. In the first embodiment, the surface roughness is preferably smaller than the size of the object to be filtered, and more preferably smaller than half the size of the object to be filtered. This is because it reduces adhesion of the object to be filtered and enables highly efficient recovery of the object to be filtered after it has been captured by the filter 1.

[0060] Fig. 10 is an enlarged view of a part of the reinforcing portion 13 in the filter portion 10. Fig. 11 is a cross-sectional view of the filter portion 10 of Fig. 10 taken along line AA.

[0061] 10 and 11, the filter section 10 is provided with a reinforcing section 13. The reinforcing section 13 is a member that reinforces the filter base section 12 and improves the mechanical strength of the filter 1. For example, the reinforcing section 13 prevents the filter base section 12 from being damaged by an external force that is applied to the filter base section 12 when a fluid containing a substance to be filtered passes through the filter section 10.

[0062] The reinforcing portion 13 is provided on the first main surface PS1 side of the filter base portion 12. The reinforcing portion 13 has a thickness t2 that is larger than the thickness t1 of the filter base portion 12.

[0063] The reinforcing portion 13 is formed in a lattice pattern when viewed from the first main surface PS1 side. The reinforcing portion 13 has a plurality of first reinforcing members 13a extending in a first direction D1 and a plurality of second reinforcing members 13b extending in a second direction D2 intersecting the first direction D1. In the first embodiment, the plurality of first reinforcing members 13a and the plurality of second reinforcing members 13b are perpendicular to each other.

[0064] The plurality of first reinforcing members 13a and the plurality of second reinforcing members 13b are formed of plate-like members. The plurality of first reinforcing members 13a and the plurality of second reinforcing members 13b are integrally formed. The plurality of first reinforcing members 13a and the plurality of second reinforcing members 13b are provided on the filter base 12 so as to straddle the plurality of through holes 11.

[0065] The plurality of first reinforcing members 13a and the plurality of second reinforcing members 13b are arranged at equal intervals. For example, the interval A1 between the plurality of first reinforcing members 13a and the interval A2 between the plurality of second reinforcing members 13b are 200 μm or more and 500 μm or less. Preferably, the intervals A1 and A2 are 250 μm or more and 350 μm or less. Note that the interval A1 refers to the distance between two adjacent first reinforcing members 13a. The interval A2 refers to the distance between two adjacent second reinforcing members 13b. In the first embodiment, the intervals A1 and A2 are approximately equal. Note that the intervals A1 and A2 may be different.

[0066] When viewing the filter portion 10 from the first main surface PS1 side, the width B1 of the plurality of first reinforcing members 13a and the width B2 of the plurality of second reinforcing members 13b are greater than the widths of the plurality of first base members 12a and the plurality of second base members 12b of the filter base portion 12. For example, the width B1 of the plurality of first reinforcing members 13a and the width B2 of the plurality of second reinforcing members 13b are 5 μm or more and 40 μm or less. Preferably, the widths B1 and B2 are 10 μm or more and 30 μm or less.

[0067] Next, the bending portion 40 will be described in detail.

[0068] Fig. 12 is a partially enlarged cross-sectional view of the curved portion 40. As shown in Fig. 12, the curved portion 40 is warped such that the outer peripheral edge of the filter 1 is raised toward the first main surface PS1. Specifically, the curved portion 40 is continuously curved toward the first main surface PS1 as it approaches the outer periphery of the filter 1. "Continuously curved" means that it is gently curved without any steps. In the first embodiment, the curved portion 40 is formed to be curved in an arched shape.

[0069] The amount of warping L1 of the curved portion 40 is 4×10 of the outer diameter d of the filter. -4 Preferably, the amount of warping L1 of the curved portion 40 is 4×10 times the outer diameter d of the filter. -3 1 times or more and 0.1 times or less. More preferably, the warpage L1 of the curved portion 40 is 0.02 times or more and 0.1 times or less the outer diameter d of the filter. The warpage L1 refers to the distance from the most warped portion of the curved portion 40, i.e., the portion farthest from a plane including the second main surface PS2 of the flat portion 30 in the thickness direction (Z direction) of the filter 1. In the first embodiment, the outer peripheral edge of the frame portion 20 corresponds to the most warped portion of the curved portion 40. For example, the warpage L1 can be measured by measuring the distance in the Z direction between the outer peripheral edge of the frame portion 20 and the flat surface when the second main surface PS2 of the filter 1 is placed in contact with the flat surface.

[0070] For example, the amount of warping L1 of the curved portion 40 may be 10 μm or more and 2.5 mm or less. This makes it easier to grasp the curved portion 40 with an instrument such as tweezers that has a thin tip. Alternatively, the curved portion 40 can be significantly deformed by spraying compressed gas (air gun) onto it, creating an opportunity to grasp it. Preferably, the amount of warping L1 of the curved portion 40 may be 100 μm or more and 2.5 mm or less. This prevents the filter 1 from being damaged when the filter 1 is grasped with an instrument such as commercially available tweezers. More preferably, the amount of warping L1 of the curved portion 40 may be 0.5 mm or more and 2.5 mm or less. This allows the shape of the curved portion 40 to be maintained even when the filter 1 is in contact with a liquid.

[0071] Fig. 13 is a partially enlarged perspective view of the curved portion 40. As shown in Fig. 13, a reinforcing portion 13 is provided on the first main surface PS1 side of the filter portion 10. The reinforcing portion 13 has a plurality of first reinforcing members 13a extending in a first direction D1 and a plurality of second reinforcing members 13b extending in a second direction D2 intersecting the first direction D1. In the first embodiment, the plurality of first reinforcing members 13a and the plurality of second reinforcing members 13b are orthogonal to each other in the XY plane.

[0072] When viewed from the first main surface PS1 side of the filter unit 10, the curved portion 40 is warped toward the first main surface PS1 side in a third direction D3 that intersects with the first direction D1 and the second direction D2. Specifically, the curved portion 40 is curved in a bow shape in the third direction D3 that winds around the X direction as an axis between the first direction D1 and the second direction D2 on the XY plane.

[0073] The first direction D1 and the second direction D2 are the directions in which the plurality of first reinforcing members 13a and the plurality of second reinforcing members 13b extend, respectively, and therefore have relatively high mechanical strength. Therefore, the curved portion 40 can be easily formed in a third direction D3 that is different from the first direction D1 and the second direction D2.

[0074] In the first embodiment, the area occupied by the multiple curved portions 40 on the first main surface PS1 is smaller than the area occupied by the flat portion 30 (see FIGS. 3 and 4). However, the area occupied by the multiple curved portions 40 is not limited to this. The area occupied by the multiple curved portions 40 may be larger than the area occupied by the flat portion 30. For example, the proportion of the area occupied by the multiple curved portions 40 on the first main surface PS1 may be 1% or more and 100% or less. Preferably, the proportion of the area occupied by the multiple curved portions 40 on the first main surface PS1 may be 5% or more and 50% or less. More preferably, the proportion of the area occupied by the multiple curved portions 40 on the first main surface PS1 may be 15% or more and 50% or less.

[0075] [Filter manufacturing method] An example of a method for manufacturing the filter 1 will be described with reference to FIGS. 14A to 14H.

[0076] 14A, a Cu film 51 is formed on a substrate 50. For example, the Cu film 51 is formed by sputtering using a sputtering film-forming apparatus. Alternatively, the Cu film 51 may be formed by vapor deposition using a vapor deposition apparatus. At this time, a Ti film may be formed between the substrate 50 and the Cu film 51 to improve adhesion between the substrate 50 and the Cu film 51.

[0077] 14B, a resist is applied onto the Cu film 51 and dried to form a resist film 52. For example, a photosensitive positive liquid resist (Pfi-3A manufactured by Sumitomo Chemical Co., Ltd.) is applied onto the Cu film 51 using a spin coater. Next, the resist is heated and dried using a hot plate to form the resist film 52.

[0078] 14C, the resist film 52 is exposed and developed to remove the resist film 52 from the area corresponding to the filter base portion 12. For example, an i-line stepper (Pfi-37A manufactured by Canon) is used as the exposure machine.

[0079] Development is carried out using a paddle developing device. The developer used is TMAH (Tetramethylammonium hydroxide). After exposure and development, the film is washed with water and dried.

[0080] 14D, electrolytic plating is performed using an electrolytic plating device, thereby forming a first layer 53, which is a plated film, in the area where the resist film 52 has been removed.

[0081] 14E, the resist film 52 is stripped with a stripping solution, NMP (N-methyl-2-pyrrolidone), using a resist stripping device capable of high-pressure spray processing. Thereafter, the first layer 53 is washed with IPA (isopropyl alcohol) and water, and then dried. This forms the filter base 12 having a plurality of through-holes 11 formed therein.

[0082] 14F, a resist film 54 is formed on the filter base 12, excluding a portion 54a corresponding to the reinforcing portion 13 and a portion (not shown) corresponding to the frame 20. For example, the resist film 54 is formed by applying a resist to the filter base 12 and drying it. The resist film 54 is exposed to light and developed, and the resist film 54 is removed from the portion 54a corresponding to the reinforcing portion 13 and the portion corresponding to the frame 20.

[0083] 14G, electrolytic plating is performed using an electrolytic plating apparatus. As a result, a second layer 55, which is a plating film, is formed on the portion 54a corresponding to the reinforcing portion 13 and the portion corresponding to the frame portion 20, i.e., the portion on which the resist film 54 is not formed. The current density in the electrolytic plating of the second layer 55 is different from the current density in the electrolytic plating of the first layer 53.

[0084] As shown in FIG. 14H, the resist film 54 is peeled off, and the Cu film 51 is removed by etching.

[0085] In this manner, the filter 1 can be produced.

[0086] In the above manufacturing method, the current density in the electrolytic plating of the second layer 55 that forms the reinforcing portion 13 and the frame portion 20 is different from the current density in the electrolytic plating of the first layer 53 that forms the filter base portion 12. This allows the curved portion 40 to be formed.

[0087] 15 is a table showing the results of an experiment in which the amount of warpage was measured using current density as a parameter. As shown in FIG. 15, in Example 1, the amount of warpage was measured for filters manufactured under different current densities for the first layer 53 and the second layer 55. Specifically, in Example 1, the current density for electrolytic plating of the first layer 53 was 11.5 A / dm 2 and the current density of the electrolytic plating of the second layer 55 is 24.2 A / dm 2 In Comparative Example 1, the amount of warpage was measured for a filter manufactured under the same current density conditions for the first layer 53 and the second layer 55. Specifically, in Comparative Example 1, the current density for electrolytic plating of the first layer 53 and the second layer 55 was 11.5 A / dm 2 is.

[0088] In Example 1, curved portions 40 were formed in the filter, and the amount of warping was 2 mm. In contrast, in Comparative Example 1, curved portions 40 were not formed in the filter, and the amount of warping was 0 mm.

[0089] The higher the current density, the greater the internal stress (shrinkage rate) of the plating film. Therefore, when the current densities of the first layer 53 and the second layer 55 are different, a difference in internal stress (shrinkage rate) appears between the first layer 53 and the second layer 55. In the above manufacturing method, the curved portion 40 is formed by utilizing this difference in internal stress (shrinkage rate).

[0090] In this way, by performing electrolytic plating under conditions of different current densities in forming the first layer 53 and the second layer 55, a filter 1 having a curved portion 40 can be manufactured.

[0091] [effect] The filter 1 according to the first embodiment can provide the following effects.

[0092] The filter 1 has a first main surface PS1 and a second main surface PS2 opposite to the first main surface PS1, and is provided with a filter base 12 in which a plurality of through holes 11 are formed, connecting the first main surface PS1 and the second main surface PS2. The filter base 12 has a plurality of curved portions 40 warped toward the first main surface PS1.

[0093] Such a configuration improves the ease of use of the filter 1. Specifically, the filter 1 is provided with a plurality of curved portions 40 that are warped toward the first principal surface PS1 side or the second principal surface PS2 side, making it easy to distinguish between the front and back of the filter 1.

[0094] Furthermore, when lifting the filter 1 using a tool such as tweezers, the filter 1 can be easily lifted by pinching the curved portion 40 with the tweezers. For example, when removing the filter 1 from the holder after filtration is complete, the user can easily lift the filter 1 by pinching the curved portion 40 with the tweezers. This allows the filter 1 to be easily removed from the holder. Furthermore, the filter 1 is less likely to be damaged than a flat filter.

[0095] Furthermore, when a plurality of filters 1 are stored stacked, curved portion 40 makes it easy to separate filters 1 from one another.

[0096] The filter 1 further includes a frame 20 that surrounds the periphery of the filter base 12 and conforms to the outer peripheral shape of the filter base 12. This configuration can also improve the mechanical strength of the filter 1. In addition, multiple curved portions 40 can be easily formed.

[0097] The filter 1 further includes a reinforcing portion 13 that is provided on the filter base portion 12 and has a thickness t2 that is larger than the thickness t1 of the filter base portion 12. This configuration can improve the mechanical strength of the filter 1. In addition, the mechanical strength of the curved portion 40 can also be ensured.

[0098] When viewed from the first main surface PS1 side of the filter base 12, the reinforcing portion 13 includes a plurality of first reinforcing members 13a extending in a first direction D1 and a plurality of second reinforcing members 13b extending in a second direction D2 intersecting the first direction D1. When viewed from the first main surface PS1 side of the filter base 12, the plurality of curved portions 40 are warped toward the first main surface PS1 in a third direction D3 intersecting the first direction D1 and the second direction D2. This configuration allows the warping direction of the curved portions 40 to be controlled. Specifically, the plurality of first reinforcing members 13a and the plurality of second reinforcing members 13b extend in the first direction D1 and the second direction D2, providing relatively high mechanical strength. In the third direction D3 intersecting the first direction D1 and the second direction D2, the plurality of first reinforcing members 13a and the plurality of second reinforcing members 13b are not arranged, making the filter base 12 prone to bending. Therefore, since the filter 1 is relatively prone to warping in the third direction D3, the curved portion 40 can be easily formed.

[0099] The amount of warping L1 of the curved portions 40 is 4×10 of the outer diameter d of the filter. -4 1 times or more and 0.1 times or less. This configuration further improves the ease of use of filter 1. For example, when removing filter 1 from the holder, it becomes easier to insert the tip of tweezers into bending portion 40.

[0100] The filter base 12 has a flat portion 30 in the center thereof, where the first principal surface PS1 and the second principal surface PS2 are formed flat. In cross-sectional view, the curved portions 40 are formed with the flat portion 30 sandwiched therebetween. This configuration further improves the ease of use of the filter 1. The flat portion 30 also ensures filtering performance.

[0101] The ratio of the area occupied by the curved portions 40 to the first main surface PS1 is 1% or more and 100% or less. With this configuration, the usability of the filter 1 is further improved.

[0102] The filter 1 is mainly composed of at least one of a metal and a metal oxide, and this configuration allows the mechanical strength of the filter 1 to be further improved.

[0103] Although the first embodiment has been described with reference to an example in which a plurality of curved portions 40 are formed in the filter 1, the present invention is not limited to this. For example, it is sufficient that one or a plurality of curved portions 40 are formed in the filter 1.

[0104] In the first embodiment, an example in which the curved portion 40 is warped toward the first principal surface PS1 has been described, but this is not limiting. For example, the curved portion 40 may be warped toward the second principal surface PS2. The warping direction of the curved portion 40 may be determined by, for example, appropriately adjusting the current density of the electrolytic plating used to form the first layer 53 and the second layer 55, the dimensions of the reinforcing portion 13, and / or the dimensions of the frame portion 20.

[0105] In the first embodiment, an example in which the curved portion 40 is curved in an arched shape has been described, but the shape of the curved portion 40 is not limited to an arched shape. For example, the curved portion 40 may be curved toward the first principal surface PS1 or the second principal surface PS2.

[0106] In the first embodiment, an example has been described in which the filter 1 includes the reinforcing portion 13 and the frame portion 20, but the present invention is not limited to this. The reinforcing portion 13 and the frame portion 20 are not essential components.

[0107] <Modification> A modified filter 1A will be described with reference to Figs. 16 to 23. Fig. 16 is a perspective view of the modified filter 1A seen from the first main surface PS1 side. Fig. 17 is a perspective view of the modified filter 1A seen from the second main surface PS2 side. Fig. 18 is a front view of the modified filter 1A. Fig. 19 is a rear view of the modified filter 1A. Fig. 20 is a left side view of the modified filter 1A. Fig. 21 is a right side view of the modified filter 1A. Fig. 22 is a plan view of the modified filter 1A. Fig. 23 is a bottom view of the modified filter 1A.

[0108] 16 to 23, in filter 1A, the area occupied by curved portions 40A on first main surface PS1 is larger than the area occupied by flat portions 30A, compared to filter 1 of embodiment 1. Specifically, filter 1A is substantially entirely formed of curved portions 40.

[0109] A configuration such as filter 1A can also improve usability, similar to filter 1 of embodiment 1. Furthermore, when multiple filters 1A are stored stacked, the filters 1A can be easily stacked and separated.

[0110] Although the filter 1A of the modified example is provided with the flat portion 30, the present invention is not limited to this. For example, the filter 1A does not necessarily have to be provided with the flat portion 30.

[0111] Although the present invention has been fully described in connection with the preferred embodiments with reference to the accompanying drawings, various changes and modifications will be apparent to those skilled in the art, and it is to be understood that such changes and modifications are included within the scope of the present invention as defined by the appended claims unless they depart therefrom. [Industrial Applicability]

[0112] The filter of the present invention can improve ease of use and is therefore useful for filtering fluids containing substances to be filtered. [Explanation of symbols]

[0113] 1. Filter 10 Filter section 11 Through hole 12 Filter base 12a First base member 12b Second base member 13 Reinforcement 13a First reinforcing member 13b Second reinforcing member 20 Frame 30 Flat area 40 curved section 50 boards 51 Cu film 52 Resist film 53 1st layer 54 Resist film 55 2nd layer D1 1st direction D2 2nd direction D3 Third direction PS1 First main surface PS2 2nd main screen

Claims

1. A filter for cell filtration, a filter base portion having a first main surface and a second main surface opposite to the first main surface, the filter base portion having a plurality of through holes formed therein that communicate between the first main surface and the second main surface; a reinforcing portion provided on the filter base portion and having a thickness greater than that of the filter base portion; Equipped with the filter base portion has one or more curved portions warped toward the first principal surface side or the second principal surface side, When viewed from the first main surface side of the filter base, the reinforcing portion has a plurality of first reinforcing members extending in a first direction and a plurality of second reinforcing members extending in a second direction intersecting the first direction, When viewed from the first main surface side of the filter base, the one or more curved portions are warped toward either the first main surface side or the second main surface side in a third direction intersecting the first direction and the second direction, The amount of warping of the one or more curved portions is 4×10 of the outer diameter of the filter. －４ 1 times or more and 0.1 times or less, filter.

2. Further provided is a frame portion that surrounds the periphery of the filter base portion and conforms to the outer peripheral shape of the filter base portion. The filter of claim 1 .

3. the filter base has a flat portion at the center of the filter base, where the first main surface and the second main surface are formed flat, The plurality of curved portions are formed with the flat portion sandwiched therebetween in cross section.

3. A filter according to claim 1 or 2.

4. A ratio of an area occupied by the one or more curved portions in the first main surface is 1% or more and 100% or less.

3. A filter according to claim 1 or 2.

5. The filter contains at least one of a metal and a metal oxide as a main component.

3. A filter according to claim 1 or 2.

6. When viewed from the first main surface side of the filter base, the one or more curved portions are formed on a part of the outer periphery of the filter.

3. A filter according to claim 1 or 2.

7. the filter base has a flat portion where the first main surface and the second main surface are formed flat, When viewed from the first main surface side of the filter base, the curved portions are formed opposite to each other with the flat portion interposed therebetween.

7. The filter of claim 6.

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