Electronic component storage case and electronic component storage body

Abstract

The present disclosure provides an electronic component storage case comprising a case body in which a plurality of electronic components are stored in a bulk state, wherein the case body has a flat box shape having a pair of main walls facing each other, and the inner wall surfaces of the pair of main walls satisfy the conditions of (i) and (ii) below. (i) The root mean square slope Sdq is 0.76 to 1.47. (ii) There are at most 150 structures having a Birth diameter of ≤ 25 μm and a Death diameter of ≥ 25 μm in a persistent homology per unit area of 1 mm2.

Description

Electronic component storage case and electronic component storage body

[0001] The present disclosure relates to an electronic component storage case and an electronic component storage body.

[0002] Demand for electronic components is expected to continue expanding in the medium to long term, driven by market growth in fields such as information and communications, automotive, and energy. Chip-type electronic components, such as multilayer capacitors and inductors, are supplied in two ways: a bulk method (see, for example, Patent Document 1), in which multiple electronic components are housed in a bulk state in an electronic component housing case; and a taping method, in which electronic components are housed in a carrier tape with multiple housing sections for housing electronic components. Here, "bulk state" refers to a state in which components are arranged in random orientations (no orientation restrictions).

[0003] Compared to the taping method, the bulk method allows for the reuse of electronic component storage cases, resulting in less waste material and a reduced environmental impact. Furthermore, the smaller packaging volume allows for space savings and improved logistics efficiency. Electronic component storage cases used in the bulk method are also called bulk cases.

[0004] In the bulk method, when mounting electronic components, an electronic component storage case is placed on a component supply device (bulk feeder), and the stored electronic components are sequentially removed from the case's discharge port, aligned, and supplied to the mounting machine. When removing the electronic components, problems arise, such as chip-type electronic components adhering to the inner walls of the electronic component storage case, leaving electronic components inside the storage case, or clogging near the discharge port, making it impossible to remove the electronic components.

[0005] In response to this problem, Patent Document 2 discloses a resin case that houses a large number of chip-type electronic components inside, and the surface resistance of the inner wall surface is 10 １２ It discloses an electronic component container formed to have a resistance of less than Ω, and describes that in the case of a chip with a chip-like electronic part size of 2.0 x 1.25 mm, adhesion of electronic components to the inner wall surface can be prevented.

[0006] JP-A-8-150518 Patent No. 3063500

[0007] In recent years, chip-type electronic components, which are widely used, have become increasingly smaller, and small electronic components such as 0201 size (0.25 mm × 0.125 mm) and 0402 size (0.4 mm × 0.2 mm) are sometimes used. As electronic components become smaller, simply controlling the surface resistivity of the inner wall surface, as in the electronic component housing of Patent Document 2, may not be enough to prevent electronic components from adhering to the inner wall surface of the electronic component housing case.

[0008] The present disclosure has been made in consideration of the above circumstances, and has as its main object to provide an electronic component storage case that can prevent electronic components from adhering to the inner wall surface.

[0009] The present disclosure provides an electronic component storage case including a case body for storing a plurality of electronic components in a bulk state, the case body being in the shape of a flat box having a pair of opposing main walls, the inner wall surfaces of the pair of main walls satisfying the following conditions (i) and (ii): (i) a root-mean-square slope Sdq of 0.76 to 1.47, and (ii) a structure satisfying the birth diameter ≦ 25 μm and death diameter ≧ 25 μm in persistent homology is formed within a unit area of ​​1 mm ２ There are less than 150 per unit.

[0010] Another embodiment of the present disclosure provides an electronic component housing including the electronic component housing case described above and a plurality of electronic components housed in the case main body.

[0011] The present disclosure can provide an electronic component storage case that can prevent electronic components from adhering to the inner wall surface.

[0012] FIG. 1 is a schematic perspective view showing an example of an electronic component storage case according to the present disclosure. FIG. 2 is a schematic cross-sectional view showing an example of an electronic component storage case according to the present disclosure. FIG. 3 is a laser microscope image of the inner wall surface of the main wall of the electronic component storage case, and an image diagram of a structure that satisfies Birth diameter≦25 μm and Death diameter≧25 μm. FIG. 4 is a schematic cross-sectional view showing an example of an electronic component storage case according to the present disclosure. FIG. 5 is an explanatory diagram of a method for manufacturing a case body in an electronic component storage case according to the present disclosure. FIG. 6 is a graph showing evaluation results in Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-8. FIG. 7 is a graph showing evaluation results in a comparative reference example.

[0013] Embodiments of the present disclosure will be described below with reference to the drawings and the like. However, the present disclosure can be implemented in many different forms and is not limited to the description of the embodiments exemplified below. Furthermore, to clarify the explanation, the drawings may show the width, thickness, shape, etc. of each part schematically compared to the actual form, but these are merely examples and are not intended to limit the interpretation of the present disclosure. Furthermore, in this specification and each drawing, elements similar to those described above with reference to the previous drawings will be designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0014] In this specification, when describing a mode in which another component is placed on a certain component, the terms "above" or "below" are used, unless otherwise specified, to include both a case in which another component is placed directly above or below a certain component so as to be in contact with the component, and a case in which another component is placed above or below a certain component with another component interposed therebetween. Also, in this specification, when describing a mode in which another component is placed on the surface of a certain component, the terms "on the surface side" or "on the surface" are used, unless otherwise specified, to include both a case in which another component is placed directly above or below a certain component so as to be in contact with the component, and a case in which another component is placed above or below a certain component with another component interposed therebetween.

[0015] As a result of extensive research, the inventors have found that when the inner wall surfaces of a pair of main walls of a case body of an electronic component storage case satisfy the following conditions (i) and (ii), adhesion of electronic components to the inner wall surfaces can be suppressed, thereby solving the above-mentioned problem. The electronic component storage case of the present disclosure will be described in detail below.

[0016] A. Electronic Component Storage Case FIG. 1 is a schematic perspective view showing an example of an electronic component storage case according to the present disclosure, and FIG. 2 is a schematic cross-sectional view taken along line A-A in FIG. 1. The electronic component storage case 1 shown in FIGS. 1 and 2 includes a flat, box-shaped case body 2 having a storage space therein for storing a plurality of electronic components (not shown) in bulk. The case body 2 includes a pair of opposing main walls (a first main wall W1 and a second main wall W2) and a peripheral wall R connected to the pair of main walls and disposed around the pair of main walls. The peripheral wall R of the case body 2 is provided with an outlet 3 that communicates with the storage space and allows electronic components to be discharged.

[0017] The electronic component storage case 1 further has a slide shutter 4 that can open and close the discharge port 3, and an operating unit 5 for applying an opening and closing operation to the slide shutter 4. Fig. 2 shows a state in which the discharge port 3 is closed by the slide shutter 4.

[0018] The electronic component storage case 1 according to the present disclosure has a structure in which the inner wall surfaces of a pair of main walls (a first main wall W1 and a second main wall W2) of the case body 2 (i) have a root-mean-square slope Sdq of 0.76 or more and 1.47 or less, and (ii) satisfy the Birth diameter ≦ 25 μm and the Death diameter ≧ 25 μm in persistent homology, and the structure is such that the inner wall surfaces of the pair of main walls (a first main wall W1 and a second main wall W2) of the case body 2 have a structure in which the inner wall surfaces of the pair of main walls (a first main wall W1 and a second main wall W2) of the case body 2 ... have a structure in which the inner wall surfaces of the pair of main walls (a first main wall W1 and a second main wall W2) of the case body 2 satisfy the Birth diameter ≦ 25 μm and the Death diameter ≧ 25 μm in persistent homology, and the structure is such that the inner wall surfaces of the pair of main walls (a first main wall W1 and a second main wall W2) of the case body 2 satisfy the Birth diameter ≦ 25 μm and the Death diameter ≧ 25 μm in persistent homology, and the structure is such that the inner wall surfaces of the pair of main walls (a first main wall W1 and a second main wall W2) of the case body 2 satisfy the Birth diameter ≦ 25 μm and the Death diameter ≧ 25 μm in persistent homology, and the ２ The inner wall surface of the main wall refers to the surface on the inside (storage space side) of the main wall.

[0019] In such an electronic component storage case, the root mean square slope Sdq of the inner wall surfaces of the pair of main walls of the case body is a specific value or more, so that electronic components are less likely to come into surface contact with the surfaces, and furthermore, because it is a specific value or less, electronic components are less likely to get into recesses on the surface, and even if they do get in, they are easily removed. ２Since the surface shape satisfies a specific number or less of structures that satisfy the birth diameter ≦ 25 μm and death diameter ≧ 25 μm in persistent homology per unit area, the number of structures that electronic components can easily fit into is small. Therefore, by satisfying the above conditions (i) and (ii), electronic components are less likely to adhere to the inner wall surface, and even if they do adhere, they fall off in a short time due to their own weight, allowing the electronic components to be removed efficiently.

[0020] Hereinafter, each configuration of the electronic component storage case of the present disclosure will be described in detail.

[0021] 1. Inner Wall Surfaces of Main Walls The electronic component storage case according to the present disclosure is characterized in that the inner wall surfaces of the pair of main walls of the case body satisfy the following conditions (i) and (ii):

[0022] (i) Root-mean-square slope Sdq: In the case body of the electronic component storage case according to the present disclosure, the root-mean-square slope Sdq of the inner wall surface of the main wall is 0.76 or more and 1.47 or less. In the present disclosure, the root-mean-square slope Sdq is a surface texture parameter determined in accordance with ISO 25178. The root-mean-square slope Sdq represents the average magnitude of the local gradient (i.e., the shape differential) of the surface irregularities and is a parameter that expresses the steepness of the surface irregularities. A larger value of the root-mean-square slope Sdq indicates a steeper surface. If the root-mean-square slope Sdq is too small, electronic components are more likely to come into surface contact with the inner wall surface and become more likely to adhere due to the effects of static electricity, etc. Furthermore, if the root-mean-square slope Sdq is too large, the electronic component will make point contact, but the slope of the surface irregularities will be steeper, i.e., the convex portions will have a certain height, making it easier for the electronic component to enter the concave portions between the convex portions and become attached. The root-mean-square slope Sdq is preferably 0.80 or more. On the other hand, it is preferably 1.40 or less.

[0023] In the present disclosure, the root mean square slope Sdq of the inner wall surface of the main wall can be calculated by processing coordinate data of the surface shape using analysis software. Specifically, the slope is calculated using the VK-X Series Multi-File Analysis Application of analysis software from images observed with a VK-X150 laser microscope manufactured by Keyence Corporation.

[0024] In the present disclosure, methods for achieving the root-mean-square slope Sdq of the inner wall surface of the main wall within the above range include sandblasting the mold used to manufacture the case body and sandblasting the resin molded body. By appropriately adjusting the sandblasting conditions, the root-mean-square slope Sdq of the inner wall surface of the main wall can be achieved within the above range. Specific sandblasting conditions include adjusting the type of blasting material (glass beads, alumina, ceramic beads, etc.), particle size (#80 to #800), blasting pressure, projection distance, and time during blasting, thereby achieving the root-mean-square slope Sdq within the above range. The particle size conforms to JIS R 6001-1:2017, JIS R 6001-2:2017, and JIS B 4130:1998.

[0025] (ii) Surface Shape by Persistent Homology Analysis The inner wall surfaces of the pair of main walls of the case body of the electronic component storage case according to the present disclosure have a structure that satisfies the Birth diameter ≦ 25 μm and the Death diameter ≧ 25 μm in persistent homology within a unit area of ​​1 mm ２ The number of the surface features per particle is preferably 150 or less. The number of the above structures is most preferably 0. The number of the above structures is preferably 100 or less.

[0026] "Persistent homology" is a method for characterizing the transition of m-dimensional (m=1 in this disclosure) holes in an object (in this disclosure, the set of white points in a binarized image), and allows us to examine features related to the placement of points. In this disclosure, we estimate the scale of non-vertex regions surrounded by vertices.

[0027] As described below, the birth diameter indicates the density of the contour of the non-apex region surrounded by the apex, and the death diameter indicates the scale of the non-apex region surrounded by the apex. The inventors have found that, by combining this with the condition (i) of the root-mean-square slope Sdq, the number of structures satisfying birth diameter ≦ 25 μm and death diameter ≧ 25 μm correlates with the adhesiveness of small electronic components. On the other hand, the number of structures satisfying birth diameter ≦ 10 μm and death diameter ≧ 10 μm, or the number of structures satisfying birth diameter ≦ 30 μm and death diameter ≧ 30 μm, does not correlate with the adhesiveness of small electronic components (see Comparative Reference Example, Figure 7). In this disclosure, in order to count even the loosest surrounding structures (for example, an equilateral triangle surrounded by three vertices), the same value (25 μm) is used for the upper limit of the birth diameter and the lower limit of the death diameter.

[0028] The inventors also used the least_squares function in the Python scipy library to fit data on (the number of 0201 chips attached when the number of structures satisfies the birth diameter ≦ 25 μm and death diameter ≧ 25 μm - the surface roughness parameter Sdq) so as to minimize the error (least squared error) with a two-dimensional Gaussian function. They found that the least squared error E was smaller than the least squared error E obtained when similarly fitting data on (the number of 0201 chips attached when the number of structures satisfies other birth diameters and death diameters - the surface roughness parameter Sdq). The smaller this value, the less variation there is in the tendency for electronic component adhesion, indicating the existence of a clear range where electronic component adhesion is poor. In other words, by combining the condition of the number of structures satisfying the birth diameter ≦ 25 μm and death diameter ≧ 25 μm with the condition of the root-mean-square slope Sdq, the range where electronic components are difficult to adhere can be accurately determined.

[0029] In a specific analysis method, a laser microscope image of the inner wall surface of the main wall of the electronic component storage case (where multiple recesses or protrusions are arranged two-dimensionally) is first taken. Height information of the recesses and protrusions on the inner wall surface is obtained as an image expressed in grayscale, with the highest point divided into 256 gradations from the lowest point. In the grayscale image, for example, the lower the brightness, the deeper the bottom of the recess (the higher the brightness, the higher the top height of the protrusion). The measurement conditions for the laser microscope are as follows. Note that Figure 3(A) shows an example of a laser microscope image of the inner wall surface of the main wall of the electronic component storage case.

[0030] [Measurement conditions] ・Measuring device: Keyence Corporation laser microscope VK-X150 ・Objective lens: Standard lens 10x ・Number of data pixels: 1024 pixels x 768 pixels ・Field of view: 1024 μm x 768 μm [Analysis conditions] ・Analysis software: Keyence Corporation multi-file analysis application VK-X series

[0031] Next, a 512 pixel x 512 pixel range is extracted from the acquired image, and then converted into a binary image with the vertices extracted. The conversion to a binary image can be performed using the Python libraries OpenCV and Scikit-Image. Specifically, OpenCV is used to extract areas of the grayscale image with a brightness of 25% or more, i.e., areas with height values ​​in the top 25% of the original unevenness data, and then the Peak_local_max function of Scikit-Image is used to extract the vertices from the extracted range, and the image is binarized so that the vertices are white and the non-vertices are black. The parameters of the Peak_local_max function are set to min_distance = 3, with the exception of default values.

[0032] Next, the scale of the non-vertex region surrounded by the vertices is calculated using the persistent homology method. In this method, each point in the object is gradually inflated into a sphere (here, a circle), and the time when each hole appears (the diameter of the sphere at the time of appearance, i.e., birth diameter) and the time when it disappears (the diameter of the sphere at the time of disappearance, i.e., death diameter) are identified during this process. When applied to a binarized image from which vertices have been extracted, the birth diameter indicates the density of the contours of the non-vertex region surrounded by the vertices, and the death diameter indicates the scale of the non-vertex region surrounded by the vertices.

[0033] Regarding the birth diameter and death diameter, all birth diameters and death diameters in the image are calculated using statistical analysis software (for example, the TDA library in R or the scikit-TDA library in Python). The birth diameter and death diameter are calculated in units of μm.

[0034] Thereafter, the number of holes that satisfy the conditions of birth diameter ≦ 25 μm and death diameter ≧ 25 μm was calculated for each sample, and the number of holes was calculated per unit area (1 mm ２ ) is converted into the number per 100 μm. FIG. 3B shows an image of a structure that satisfies the conditions of birth diameter≦25 μm and death diameter≧25 μm.

[0035] In the present disclosure, a structure that satisfies the birth diameter ≦ 25 μm and death diameter ≧ 25 μm in the persistent homology of the inner wall surface of the main wall is ２ Examples of methods for achieving a surface shape that satisfies the requirement of 150 particles or less per unit area include sandblasting the mold used to manufacture the case body, and sandblasting the resin molded body. The above-mentioned surface shape can be achieved by appropriately changing the sandblasting conditions. Specific sandblasting conditions include the type of shot material (glass beads, alumina, ceramic beads, etc.), particle size (#80 to #800), processing pressure during blasting, projection distance, and time, and by adjusting these, a structure that satisfies the requirements of birth diameter ≦ 25 μm and death diameter ≧ 25 μm can be achieved per unit area of ​​1 mm.２ The number of pieces per unit area can be 150 or less.

[0036] (iii) Others The case body of the electronic component storage case according to the present disclosure has a surface resistivity of the inner wall surface of the main wall of 1×10 １０ It is preferably less than Ω / □, and more preferably less than 6.0 × 10 ９ Ω / □ or less. If the surface resistivity is less than the above value, static electricity can be suppressed, and adhesion of electronic components to the inner wall surface can be further suppressed. The above surface resistivity can be obtained by adjusting the type and content of the antistatic agent contained in the material of the case body.

[0037] The surface resistivity was measured using a surface resistivity measuring device (manufactured by Nitto Seiko Co., Ltd., device name "Hiresta-UP MCP-HT450") under the following measurement conditions in an environment of a temperature of 25±4°C and a humidity of 50±10%. (Measurement conditions) Terminal: URS Applied voltage: 1000V

[0038] In the present disclosure, examples of a method for setting the surface resistivity of the inner wall surface of the main wall within the above range include a method of using a resin and an antistatic agent as described below in "2. Electronic component storage case (1) Case body" and adjusting the amount of antistatic agent added.

[0039] 2. Electronic Component Storage Case (1) Case Body The electronic component storage case according to the present disclosure has a case body. As shown in Figures 1 and 2, the case body includes a pair of opposing main walls (a first main wall W1 and a second main wall W2) and a peripheral wall R connected to the pair of main walls and disposed around the pair of main walls. The case body has a flat box shape and includes a storage space therein for storing multiple bulk electronic components.

[0040] The first main wall W1 and the second main wall W2 face each other substantially parallel to each other and extend substantially perpendicular to the thickness direction of the case body 2. The shapes of the first main wall W1 and the second main wall W2 are, for example, substantially rectangular. The dimensions of the first main wall W1 and the second main wall W2 are not particularly limited as long as they are sizes that allow installation in a mounting device. The first main wall W1 and the second main wall W2 may have the same shape and dimensions or may be different. The inner wall surfaces of the first main wall W1 and the second main wall W2 may have inclined surfaces.

[0041] The peripheral wall R has multiple walls that connect the pair of main walls and are arranged around the first main wall W1 and the second main wall W2. In Fig. 1 , the peripheral wall R has a first wall Ra, a second wall Rb, a third wall Rc, and a fourth wall Rd. The peripheral wall is provided with an outlet 3 that communicates with the storage space and is used to discharge electronic components. In Fig. 1 , the outlet 3 is provided in the first wall Ra.

[0042] As shown in Figures 1 and 2, the peripheral wall R may have a sloped portion S that increases in thickness toward the discharge opening 3. By providing such a sloped portion S, when the electronic component storage case is installed in a component supply device with the discharge opening 3 facing downward, electronic components can be easily removed from the discharge opening of the electronic component storage case. Figure 4 is a schematic cross-sectional view showing an example of an electronic component storage case according to the present disclosure. As shown in Figure 4, the electronic component storage case 1 according to the present disclosure does not need to have the sloped portion S.

[0043] In the present disclosure, it is preferable that the inner wall surface of the peripheral wall also satisfies the above conditions (i) and (ii).

[0044] Furthermore, in the case body according to the present disclosure, at least a portion of the outer wall surfaces (the outer wall surfaces of the main wall and the outer wall surfaces of the peripheral wall) may satisfy the above conditions (i) and (ii). Methods for making the outer wall surfaces have a surface shape that satisfies the above conditions (i) and (ii) include the same methods as those detailed in "1. Inner wall surface of the main wall" above.

[0045] The material of the case body of the electronic component storage case is preferably a material that can achieve a surface resistivity within the above-mentioned range, and preferably contains a resin and an antistatic agent. By containing an antistatic agent, the surface resistance of the inner wall surface of the storage case can be reduced. Alternatively, a material in which the resin itself has an antistatic function can be used.

[0046] Examples of resins include acrylic resins, styrene-based resins, crystalline polyolefins, polyesters, polycarbonates, ethylene-(meth)acrylic acid copolymers or ionomers thereof. Examples of acrylic resins include polymethyl methacrylate (PMMA). Examples of styrene-based resins include polystyrene (PS) and acrylonitrile-butadiene-styrene resin (ABS). Examples of crystalline polyolefins include polyethylene (PE), polypropylene (PP), poly3-methyl-1-butene, and poly4-methyl-1-pentene. Examples of polyesters include polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN). These resins can be used alone or in combination, and can also be used in combination with the antistatic agent described below.

[0047] The antistatic agent is not particularly limited as long as it can bring the surface resistivity into the above-mentioned range, and examples thereof include known surfactants and conductive substances.

[0048] The case body is preferably transparent, so that the remaining amount of electronic components can be visually confirmed. For example, the case body in the present disclosure preferably has a total light transmittance of 75% or more, and particularly preferably 80% or more. In the present disclosure, the total light transmittance is a value measured in accordance with JIS-K-7361 using a HAZE METER HM-150 (manufactured by Murakami Color Research Laboratory Co., Ltd.).

[0049] (2) Slide Shutter and Operation Unit As shown in Fig. 2, the electronic component storage case 1 preferably has a slide shutter 4 that can open and close the discharge port. In this case, the electronic component storage case 1 has an operation unit 5 that applies an opening and closing operation to the slide shutter 4. The operation unit 5 is, for example, connected to one end of the slide shutter 4 and is provided slidably. For example, when the operation unit 5 is operated in the direction opposite to the discharge port 3 (direction O in Fig. 2), the slide shutter 4 opens, and when the operation unit 5 is operated toward the discharge port (direction C in Fig. 2), the slide shutter 4 closes.

[0050] (3) Others The electronic component storage case may have a connecting portion that allows it to be detachably attached to the component supply device.

[0051] 3. Manufacturing Method The manufacturing method of the case body of the electronic component storage case of the present disclosure is not particularly limited, but can be, for example, as shown in Fig. 5, by the steps of preparing a first member 2A including a first main wall W1 having a wall surface that satisfies the above-mentioned conditions and a second member 2B including a second main wall W2 having a wall surface that satisfies the above-mentioned conditions (Fig. 5(a)), and assembling and welding the first member 2A and the second member 2B so that the wall surfaces that satisfy the above-mentioned conditions face each other (welding step) (Fig. 5(b)). The first member and the second member can be, for example, a main body portion and a lid portion.

[0052] (1) Component Preparation Step In this step, a first component including a first main wall having a wall surface satisfying the above-described conditions and a second component including a second main wall having a wall surface satisfying the above-described conditions are prepared. As shown in FIG. 5 , the first component 2A preferably includes a first peripheral wall R1 provided around the first main wall W1. Similarly, the second component 2B preferably includes a second peripheral wall R2 provided around the second main wall W2. The first peripheral wall R1 and the second peripheral wall R2 constitute the peripheral wall R after the welding step.

[0053] A specific method for preparing the first member 2A and the second member 2B is as follows. First, multiple types (e.g., approximately 20 types) of injection molding dies with different surface conditions are prepared. Next, the above-mentioned case body material is melt-mixed and injected into the injection molding dies in a fluid state, followed by molding (injection molding) to produce multiple types (e.g., approximately 20 types) of candidate members. From the multiple candidate members produced, one whose main wall surface satisfies the above-mentioned conditions (i) and (ii) is selected and prepared as the first member. The second member is selected and prepared in a similar manner. It is preferable that the multiple types of injection molding dies have different surface conditions due to blasting processes being performed under different conditions during mold production.

[0054] The conditions for the blasting process are the same as those described above in "1. Inner wall surface of the main wall (i) Root mean square slope Sdq" and "1. Inner wall surface of the main wall (ii) Surface shape by persistent homology analysis," and therefore will not be described here.

[0055] (2) Welding Step This step is a step of manufacturing a case body by assembling and welding the first and second members so that their wall surfaces that satisfy the above-mentioned conditions face each other. For example, it is preferable to use an ultrasonic welding machine to weld the ends of the first peripheral wall R1 of the first member 2A and the second peripheral wall R2 of the second member 2B to each other. This results in a case body in which the first main wall W1 and the second main wall W2 face each other and whose inner wall surfaces satisfy the above-mentioned conditions.

[0056] B. Electronic Component Storage Body The present disclosure provides an electronic component storage body having the above-described electronic component storage case and a plurality of electronic components stored in the case body. The electronic component storage body of the present disclosure can prevent electronic components from adhering to the inner wall surface, thereby enabling efficient removal of electronic components. Furthermore, bulk-type electronic component storage bodies using electronic component storage cases have a smaller packaging volume than taping-type packaging bodies, thereby saving space and improving logistics efficiency. Furthermore, the electronic component storage case can be reused after the electronic components are mounted. Therefore, there is less waste material after mounting, reducing the environmental burden.

[0057] 1. Electronic Component Storage Case The electronic component storage case in the present disclosure is similar to the above-described "A. Electronic Component Storage Case."

[0058] 2. Electronic Components The electronic components used in the electronic component container of the present disclosure are not particularly limited, and examples thereof include chip-type electronic components such as capacitors and resistors. Among these, a multilayer ceramic capacitor is particularly preferred.

[0059] Examples of the shape of the electronic component include a prismatic shape and a cylindrical shape. The size of the prismatic electronic component is preferably a length of 0.1 mm to 2.0 mm, more preferably 0.2 mm to 1.6 mm, even more preferably 0.25 mm to 0.6 mm, and particularly preferably 0.25 mm to 0.4 mm. The width is preferably 0.1 mm to 1.25 mm, more preferably 0.12 mm to 0.8 mm, even more preferably 0.125 mm to 0.3 mm, and particularly preferably 0.125 mm to 0.2 mm. The thickness is preferably 0.1 mm to 1.25 mm, more preferably 0.12 mm to 0.8 mm, even more preferably 0.125 mm to 0.3 mm, and particularly preferably 0.125 mm to 0.2 mm.

[0060] The electronic components used in the electronic component housing of the present disclosure are preferably any of the 0201, 0402, and 0603 sizes. The effects of the present invention can be particularly pronounced with the 0201 and 0402 sizes. These dimensional symbols are specified in JIS C 5101-22:2021, Appendix A (Specifications), Guidelines for Dimensional Symbols and Standards for Surface-Mount Fixed Multilayer Ceramic Capacitors, Type 2. Specifically, the 0201 size has a length x width of 0.25 mm x 0.125 mm, the 0402 size has a length x width of 0.4 mm x 0.2 mm, and the 0603 size has a length x width of 0.6 mm x 0.3 mm. The (length) x (width) x (thickness) of the 0201 size, including thickness, is, for example, 0.25 mm x 0.125 mm x 0.125 mm, the 0402 size is 0.4 mm x 0.2 mm x 0.2 mm, and the 0603 size is 0.6 mm x 0.3 mm x 0.3 mm. Note that the above length, width, and thickness may have tolerances as described in Appendix A above. For example, the length (0.25 mm) of the 0201 size may have tolerances within ±0.013 mm.

[0061] The weight of the electronic component may be, for example, 0.01 mg or more and 2.0 mg or less, 0.05 mg or more and 2.0 mg or less, 0.1 mg or more and 1.0 mg or less, or 0.2 mg or more and 0.6 mg or less.

[0062] 3. Electronic Component Container The electronic component container in the present disclosure is used for storing and transporting electronic components. The electronic components are stored and transported in the container state. During mounting, the container is placed on a component supply device (bulk feeder), and the electronic components are sequentially removed from the outlet, aligned, and supplied to the mounting machine.

[0063] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any configuration that is substantially identical to the technical idea described in the claims of the present disclosure and that provides similar effects is included within the technical scope of the present disclosure.

[0064] The present disclosure will be described in more detail below with reference to examples and comparative examples.

[0065] (Examples 1-1 to 1-9, Comparative Examples 1-1 to 1-8) The root mean square slope Sdq and the number of structures (unit area 1 mm 2 ) with a birth diameter ≦ 25 μm and a death diameter ≧ 25 μm in persistent homology shown in Table 1 ２ Resin substrates having a surface with a resistivity of 4.54 × 10 were prepared. These values ​​were measured under the measurement conditions described in "A. Electronic component storage case 1. Inner wall surface of main wall (i) Root mean square slope Sdq" and "A. Electronic component storage case 1. Inner wall surface of main wall (ii) Surface shape by persistent homology analysis" above. Novalloy E81 manufactured by Daicel Corporation was used as the material for each resin substrate, and the surface resistivity of each resin substrate was 4.54 × 10 ９ The resistance was Ω / □. The resin substrate was placed horizontally, and the following evaluation chips were supplied to the surface of the resin substrate. The resin substrate was gently shaken to spread the evaluation chips on the surface of the resin substrate. The resin substrate was slowly inverted and held for 1 second, and then returned to its original horizontal state. An image of the resin substrate was taken, and the number of evaluation chips attached to the resin substrate was counted by image analysis. The number of attached evaluation chips was evaluated according to the following evaluation criteria. The results are shown in Table 1.

[0066] - Evaluation chip Multilayer ceramic capacitor (prismatic type MLCC) Dimensions 0201 chip (0.25mm x 0.125mm x 0.125mm, approx. 0.016mg) approx. 0.8g 0402 chip (0.40mm x 0.20mm x 0.20mm, approx. 0.09mg) approx. 0.50g

[0067] Evaluation criteria: B: Less than 1,400 0201 chips and less than 70 0402 chips. C: 1,400 or more 0201 chips or 70 or more 0402 chips. Furthermore, among B chips, those with less than 1,000 0201 chips and less than 50 0402 chips were evaluated as "A."

[0068]

[0069] The above evaluation results were plotted on a graph with the number of structures satisfying the birth diameter ≦ 25 μm and death diameter ≧ 25 μm in persistent homology on the horizontal axis and the root mean square slope Sdq on the vertical axis, and the results are shown in Figure 6. The evaluation results of "A" in Table 1 are indicated by "◎", the evaluation results of "B" are indicated by "◯", and the evaluation results of "C" are indicated by "×". The results of Figure 6 confirmed that adhesion of electronic components to the inner wall surface can be suppressed if the surface satisfies the above-mentioned conditions (i) and (ii).

[0070] (Experimental Example) The data (number of 0201 chips attached when the number of structures satisfying birth diameter ≦ 25 μm and death diameter ≧ 25 μm - surface roughness parameter Sdq) was fitted using the least_squares function in the Python scipy library to minimize the error (least square error) with a two-dimensional Gaussian function. The least square error E ((count0201-B25_D25)-Sdq) was calculated according to the method described in the following URL: (URL: https: / / docs.scipy.org / doc / scipy / reference / generated / scipy.optimize.least_squares.html) (Retrieved November 11, 2021)

[0071] Furthermore, the least square error E was also calculated when the data of (the number of 0201 chips attached for the number of structures satisfying other birth diameters and death diameters - the surface roughness parameter Sdq) was similarly fitted. The results are shown below. E((count0201-B25_D25)-Sdq): 0.125575 E((count0201-B30_D30)-Sdq): 0.297466 E((count0201-B15_D15)-Sdq): 0.5 E((count0201-B10_D10)-Sdq): 0.5 E((count0201-B25_D25)-Sdq) is smaller than the other least square errors E, and by combining the condition of the number of structures that satisfy Birth diameter ≦ 25 μm and Death diameter ≧ 25 μm with the condition of the root mean square slope Sdq, the range where electronic components are less likely to adhere was confirmed.

[0072] (Comparative Reference Examples) The evaluation results of the resin substrates of Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-8 are shown in the table below. The root mean square slope Sdq is plotted on the vertical axis, and the number of structures (unit area 1 mm2) that satisfy the Birth diameter ≦ 10 μm and Death diameter ≧ 10 μm in persistent homology is plotted on the vertical axis. ２ The results are shown in Figure 7. When the evaluation criteria based on persistent homology were set to birth diameter ≦ 10 μm and death diameter ≧ 10 μm, it was confirmed that no correlation with the adhesion of electronic components was obtained.

[0073] That is, the present disclosure provides the following inventions. [1] An electronic component storage case including a case body in which a plurality of electronic components are stored in a bulk state, the case body having a flat box shape with a pair of opposing main walls, and the inner wall surfaces of the pair of main walls satisfy the following conditions (i) and (ii): (i) The root mean square slope Sdq is 0.76 or more and 1.47 or less. (ii) A structure satisfying the birth diameter ≦ 25 μm and death diameter ≧ 25 μm in persistent homology is formed within a unit area of ​​1 mm ２ [2] The inner wall surfaces of the pair of main walls have a surface resistivity of 1×10 １０ [3] An electronic component storage body having the electronic component storage case according to [1] or [2] and a plurality of electronic components stored in the case main body.

[0074] REFERENCE SIGNS LIST 1: Electronic component storage case 2: Case body 3: Discharge port 4: Slide shutter 5: Operation unit

Claims

1. An electronic component storage case having a case body in which a plurality of electronic components are stored in a bulk state, the case body being in the shape of a flat box having a pair of opposing main walls, the inner wall surfaces of the pair of main walls satisfying the following conditions (i) and (ii): (i) the root mean square slope Sdq is 0.76 or more and 1.47 or less, (ii) a structure that satisfies the birth diameter ≦ 25 μm and death diameter ≧ 25 μm in persistent homology is within a unit area of ​​1 mm ２ There are 150 or less per unit.

2. The inner wall surfaces of the pair of main walls have a surface resistivity of 1×10 １０ The electronic component storage case according to claim 1 , wherein the resistance is less than Ω / □.

3. An electronic component storage body comprising: an electronic component storage case according to claim 1 or 2; and a plurality of electronic components stored in the case body.

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