Electronic component storage case and electronic component storage body

Abstract

To provide an electronic component storage case capable of suppressing attaching of an electronic component to an internal wall surface.SOLUTION: An electronic component storage case includes a case body in which a plurality of electronic components is stored in a bulk state. The case body has a flat box shape having a pair of main walls opposing to each other. Internal wall surfaces of the pair of main walls satisfy the following conditions of (i) and (ii). (i) The root-mean-square inclination Sdq is equal to or greater than 0.76 and equal to or less than 1.47.(ii) The structure which satisfies Birth diameter≤25 μm and Death diameter≥25 μm in persistent homology is equal to or less than 150 pieces per a unit area 1 mm2.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Demand for electronic components is expected to continue to expand 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, can be supplied in a bulk state (bulk method) in which a large number of electronic components are housed in an electronic component case (for example, Patent Document 1), or in a taping method in which electronic components are housed in a carrier tape with multiple housings for housing electronic components. Here, "bulk state" means a state in which the components are all oriented in a random manner (no orientation restrictions).

[0003] Compared to the taping method, the bulk method allows electronic component storage cases to be reused, so there is less waste material and it is possible to reduce the burden on the environment. In addition, since the packaging volume is small, it is possible to save space and improve 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 occur such as chip-type electronic components adhering to the inner wall surface of the electronic component storage case, leaving electronic components inside the storage case or becoming clogged near the discharge port, making it impossible to remove the electronic components.

[0005] In response to such problems, Patent Document 2 describes a resin case that contains a large number of chip-type electronic components, and has an inner wall surface with a surface resistance of 10 12An electronic component storage body is disclosed that is formed so that the resistance is less than Ω, and it is stated that for chips with chip-like electronic parts of size 2.0 x 1.25 mm, adhesion of electronic components to the inner wall surface can be prevented. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 8-150518 [Patent Document 2] Patent No. 3063500 Summary of the Invention [Problem to be solved by the invention]

[0007] In recent years, chip-type electronic components that are widely used are becoming smaller, and small electronic components such as 0201 size (0.25 mm x 0.125 mm) and 0402 size (0.4 mm x 0.2 mm) are sometimes used. As electronic components become smaller, there are cases where adhesion of electronic components to the inner wall surface of an electronic component storage case cannot be suppressed simply by controlling the surface resistivity of the inner wall surface as in the electronic component storage body of Patent Document 2.

[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. [Means for solving the problem]

[0009] The present disclosure provides 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 being in a flat box shape having a pair of opposing main walls, and 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 greater than or equal to 0.76 and less than or equal to 1.47. (ii) The structure that satisfies the birth diameter ≦ 25 μm and the death diameter ≧ 25 μm in the persistent homology is 2 There are 150 or less per

[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 body. Effect of the Invention

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

[0012] [Figure 1] 1 is a schematic perspective view showing an example of an electronic component storage case according to the present disclosure. [Diagram 2] 1 is a schematic cross-sectional view showing an example of an electronic component storage case according to the present disclosure. [Diagram 3] 1 is a laser microscope image of the inner wall surface of the main wall of an electronic component storage case, and an image of a structure that satisfies the birth diameter ≦ 25 μm and death diameter ≧ 25 μm. [Figure 4] 1 is a schematic cross-sectional view showing an example of an electronic component storage case according to the present disclosure. [Diagram 5] 5A to 5C are explanatory diagrams of a manufacturing method for a case body in the electronic component storage case according to the present disclosure. [Figure 6] 1 is a graph showing the evaluation results in Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-8. [Figure 7] 13 is a graph showing the evaluation results in the comparative reference example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The following describes the embodiments of the present disclosure with reference to the drawings. However, the present disclosure can be implemented in many different forms, and should not be interpreted as being limited to the description of the embodiments exemplified below. In addition, the drawings may be schematic in terms of the width, thickness, shape, etc. of each part compared to the actual form in order to make the explanation clearer, but these are merely examples and do not limit the interpretation of the present disclosure. In this specification and each figure, elements similar to those described above with respect to the previous figures may be given the same reference numerals, and detailed explanations may be omitted as appropriate.

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

[0015] As a result of intensive 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 below-described (i) and (ii), adhesion of electronic components to the inner wall surfaces can be suppressed, thereby solving the above problem. The electronic component storage case of the present disclosure will be described in detail below.

[0016] A. Electronic parts 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 AA 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 for storing a plurality of electronic components (not shown) in bulk therein. 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 is used to discharge electronic components.

[0017] The electronic component storage case 1 further has a slide shutter 4 capable of opening and closing the discharge outlet 3, and an operation unit 5 for applying an opening and closing operation to the slide shutter 4. Fig. 2 shows a state in which the discharge outlet 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 have (i) a root mean square slope Sdq of 0.76 or more and 1.47 or less, and (ii) a structure that satisfies a birth diameter ≦ 25 μm and a death diameter ≧ 25 μm in persistent homology, are formed within a unit area of ​​1 mm 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 unlikely to come into surface contact with the surfaces, and because it is below a specific value, electronic components are unlikely to get into the recesses on the surface, and even if they do get in, they are likely to come out. 2 Since the surface shape has a specific number 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 can easily accommodate electronic components 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 will fall off due to their own weight in a short time, allowing the electronic components to be removed efficiently.

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

[0021] 1. Inner surface of main wall The electronic component storage case according to the present disclosure is characterized in that the inner wall surfaces of a 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 in 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 property parameter determined in accordance with ISO 25178. The root-mean-square slope Sdq represents the average magnitude of the local gradient (= shape derivative) of the uneven shape of the surface, and is a parameter expressing the steepness of the unevenness on the surface. The larger the value of the root-mean-square slope Sdq, the steeper the surface. If the root-mean-square slope Sdq is too small, the electronic component is likely to come into surface contact with the inner wall surface, and is difficult to remove due to the influence of static electricity, etc. Also, if the root-mean-square slope Sdq is too large, the electronic component will be in point contact, but the slope of the surface unevenness will be steeper, that is, the convex parts will have a certain height, so that the electronic component will easily enter the concave parts between the convex parts and will be difficult to remove. The root mean square slope Sdq is preferably 0.80 or more, and 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 the coordinate data of the surface shape with analysis software. Specifically, the slope is calculated by the analysis software VK-X series multi-file analysis application from an image observed with a laser microscope VK-X150 manufactured by Keyence Corporation.

[0024] In the present disclosure, the method of setting the root mean square slope Sdq of the inner wall surface of the main wall in the above range includes a method of performing sandblasting on a mold used for manufacturing the case body, and a method of performing sandblasting on a resin molded body. By appropriately changing the conditions of the sandblasting, the root mean square slope Sdq of the inner wall surface of the main wall can be set in the above range. As specific conditions of the sandblasting, the type of blasting material (glass beads, alumina, ceramic beads, etc.) and the particle size (#80 to #800), the processing pressure during the blasting, the projection distance, the time, etc. can be adjusted to set the root mean square slope Sdq in the above range. The above particle size complies with JIS R 6001-1:2017, JIS R 6001-2:2017, and JIS B 4130:1998.

[0025] (ii) Surface topography by persistent homology analysis The inner wall surfaces of a 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 the persistent homology, within a unit area of ​​1 mm 2 The number of the above structures is 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 (in this disclosure, m=1) holes in an object (in this disclosure, the set of white points in a binarized image), and persistent homology allows us to examine features related to the arrangement of points. In this disclosure, we estimate the scale of the non-vertex region surrounded by the vertices.

[0027] As described later, 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 the number of structures that satisfy birth diameter ≦ 25 μm and death diameter ≧ 25 μm is correlated with the adhesiveness of small electronic components by combining with the above condition (i) root mean square slope Sdq. On the other hand, the inventors have found that the number of structures that satisfy birth diameter ≦ 10 μm and death diameter ≧ 10 μm, and the number of structures that satisfy birth diameter ≦ 30 μm and death diameter ≧ 30 μm are not correlated with the adhesiveness of small electronic components (see Comparative Reference Example, FIG. 7). In this disclosure, the same value (25 μm) is used for the upper limit of the birth diameter and the lower limit of the death diameter in order to count the loosest surrounding structure (for example, an equilateral triangle surrounded by three apexes).

[0028] The inventors also found that the least square error E when fitting data (the number of 0201 chips attached when the number of structures satisfying Birth diameter ≦ 25 μm and Death diameter ≧ 25 μm - surface roughness parameter Sdq) using the least_squares function of the Python scipy library so as to minimize the error (least square error) value with a two-dimensional Gaussian function is smaller than the least square error E when fitting data (the number of 0201 chips attached when the number of structures satisfying other Birth diameters and Death diameters - surface roughness parameter Sdq). The smaller the value, the less the variation in the tendency of electronic component adhesion and the clear presence of a range where electronic component adhesion is low. That is, by combining the condition of the number of structures satisfying 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] As a specific analysis method, first, a laser microscope image of the inner wall surface (where multiple recesses or protrusions are arranged two-dimensionally) of the main wall of the electronic component storage case is taken. Height information of the recesses and protrusions on the inner wall surface is obtained as an image expressed in grayscale, which is divided into 256 gradations from the highest point to 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 FIG. 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] Measurement equipment: Keyence Laser Microscope VK-X150 Objective lens: Standard lens 10x Data pixel count: 1024 pixels x 768 pixels Field of view: 1024μm×768μm [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 the image is converted into a binary image with the vertices extracted. The conversion into 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. Default values ​​are used for the parameters of the Peak_local_max function, except for min_distance=3.

[0032] Next, the scale of the non-vertex regions surrounded by the vertices is calculated using persistent homology. In this method, each point in the object is gradually inflated into a sphere (here, a circle), and the time when each hole appeared (the diameter of the sphere at the time of its appearance, i.e., birth diameter) and the time when it disappeared (the diameter of the sphere at the time of its disappearance, i.e., death diameter) are identified. When applied to a binarized image with vertices extracted, the birth diameter indicates the fineness of the contour of the non-vertex regions surrounded by the vertices, and the death diameter indicates the scale of the non-vertex regions surrounded by the vertices.

[0033] Regarding the birth and death diameters, we use statistical analysis software (such as the R TDA library or the Python scikit-TDA library) to calculate all birth and death diameters in the image. The units of birth and death diameters are converted to the μm scale.

[0034] Then, the number of holes that satisfy the birth diameter ≦ 25 μm and death diameter ≧ 25 μm was calculated for each sample, and the number of holes was calculated by dividing the number of holes by the unit area (1 mm 2 The number of deaths per 100 μm is calculated by converting the number of deaths per 100 μm into the number of deaths per 100 μm.

[0035] In this disclosure, the structure that satisfies the birth diameter ≦ 25 μm and the death diameter ≧ 25 μm in the persistent homology of the inner wall surface of the main wall is 2Examples of methods for achieving a surface shape that satisfies the requirement of 150 particles or less per unit area include a method of sandblasting the mold used to manufacture the case body, and a method of sandblasting the resin molded body. The above-mentioned surface shape can be achieved by appropriately changing the conditions for sandblasting. Specific conditions for sandblasting include the type of blasting material (glass beads, alumina, ceramic beads, etc.) and particle size (#80 to #800), the processing pressure during blasting, the projection distance, and the time, and by adjusting these, a structure that satisfies the birth diameter ≦ 25 μm and death diameter ≧ 25 μm can be achieved per unit area of ​​1 mm2. 2 The number of pieces per unit may be 150 or less.

[0036] (iii) Other The case body of the electronic component storage case according to the present disclosure has a surface resistivity 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 temperature 25±4°C and humidity 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 parts storage case (1) Case body The electronic component storage case according to the present disclosure has a case body. As shown in Fig. 1 and Fig. 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 has a storage space therein for storing a plurality of 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 shape of the first main wall W1 and the second main wall W2 is, 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 a size that allows 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 have different shapes and dimensions. The inner wall surfaces of the first main wall W1 and the second main wall W2 may have an inclined surface portion.

[0041] The peripheral wall R has a plurality of walls, connects the pair of main walls, and is disposed 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 Fig. 1 and Fig. 2, the peripheral wall R may have an inclined portion S that becomes thicker toward the discharge opening 3. By having such an inclined portion S, when the electronic component storage case is placed on a component supplying device with the discharge opening 3 facing downward, electronic components can be easily removed from the discharge opening of the electronic component storage case. Fig. 4 is a schematic cross-sectional view showing an example of an electronic component storage case according to the present disclosure. As shown in Fig. 4, the electronic component storage case 1 according to the present disclosure does not need to have the inclined 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] In addition, in the case body according to the present disclosure, at least a part of the outer wall surface (the outer wall surface of the main wall and the outer wall surface of the peripheral wall) may satisfy the above conditions (i) and (ii). Methods for making the outer wall surface into 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 set the surface resistivity within the above-mentioned range, and preferably contains a resin and an antistatic agent. By containing the antistatic agent, the surface resistance of the inner wall surface of the storage case can be reduced. In addition, a material in which the resin itself has an antistatic function can also be used.

[0046] Examples of the resin include acrylic resin, styrene resin, crystalline polyolefin, polyester, polycarbonate, ethylene-(meth)acrylic acid copolymer or its ionomer. Examples of the acrylic resin include polymethylmethacrylate (PMMA). Examples of the styrene resin include polystyrene (PS) and acrylonitrile-butadiene-styrene resin (ABS). Examples of the crystalline polyolefin include polyethylene (PE), polypropylene (PP), poly3-methyl-1-butene, poly4-methyl-1-pentene, etc. Examples of the polyester include polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), etc. 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 of the antistatic agent 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 capable of opening and closing the discharge port. In this case, the electronic component storage case 1 has an operation unit 5 for applying 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 it is operated in the discharge port direction (direction C in Fig. 2), the slide shutter 4 closes.

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

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

[0052] (1) Material preparation process In this step, a first member including a first main wall having a wall surface satisfying the above-mentioned conditions and a second member including a second main wall having a wall surface satisfying the above-mentioned conditions are prepared. As shown in FIG. 5, the first member 2A preferably includes a first peripheral wall R1 provided around the first main wall W1. Similarly, the second member 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 form 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., about 20 types) of injection molds with different surface conditions are prepared. Next, the above-mentioned case body material is melt-mixed, injected in a fluid state into the injection mold, and molded (injection molding) to produce multiple types (e.g., about 20 types) of candidate members. From the multiple candidate members thus manufactured, 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 molds have different surface conditions as a result of being subjected to blasting treatment 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”, so a detailed explanation will be omitted here.

[0055] (2) Welding process This process is a process for 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 makes it possible to obtain a case body in which the first main wall W1 and the second main wall W2 face each other and the inner wall surfaces of these walls satisfy the above-mentioned conditions.

[0056] B. Electronic component storage unit The present disclosure provides an electronic component storage body having the above-mentioned 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 suppress adhesion of electronic components to the inner wall surface, so that electronic components can be efficiently removed. Furthermore, a bulk-type electronic component storage body using an electronic component storage case has a smaller packaging volume than a taping-type package, so that space can be saved and logistics efficiency can be improved. Furthermore, the electronic component storage case can be reused after mounting the electronic components. Therefore, there is less waste material after mounting, and the environmental burden can be reduced.

[0057] 1. Electronic parts storage case The electronic component storage case in this disclosure is similar to the above-mentioned "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 them, a multilayer ceramic capacitor is particularly preferred.

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

[0060] The electronic components used in the electronic component container of the present disclosure are preferably any of 0201 size, 0402 size, and 0603 size. In particular, the effects of the present invention can be obtained more remarkably with the 0201 size and 0402 size. These dimensional symbols are specified in the guidelines for dimensional symbols and specifications for fixed multilayer ceramic capacitors type 2 for surface mounting in JIS C 5101-22:2021 Appendix A (regulations). Specifically, the 0201 size is 0.25 mm x 0.125 mm in length x width, the 0402 size is 0.4 mm x 0.2 mm, and the 0603 size is 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. The above length, width, and thickness may have the tolerances described in Appendix A above. For example, the length (0.25 mm) of the 0201 size may have an error of 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 storage unit The electronic component housing in the present disclosure is used for storing and transporting electronic components. The electronic components are stored and transported in the housing state. During mounting, the housing is placed on a component supply device (bulk feeder), and the electronic components are sequentially taken out from a discharge port, aligned, and supplied to a mounting machine.

[0063] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present disclosure and exhibits similar effects is included in the technical scope of the present disclosure. EXAMPLES

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

[0065] (Examples 1-1 to 1-9, Comparative Examples 1-1 to 1-8) The number of structures with a birth diameter of ≦25 μm and a death diameter of ≧25 μm in the root mean square slope Sdq and persistent homology shown in Table 1 (unit area 1 mm 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 onto 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 capacitors (prismatic 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: 1400 or more 0201 chips, or 70 or more 0402 chips Furthermore, among B, Less than 1,000 0201 chips and less than 50 0402 chips were rated as "A."

[0068] [Table 1]

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

[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 of Python's scipy library to minimize the error (least squared error) value with a two-dimensional Gaussian function, and the least squared error E ((count0201-B25_D25)-Sdq) was calculated according to the method described in the URL below. (URL: https: / / docs.scipy.org / doc / scipy / reference / generated / scipy.optimize.least_squares.html) (Retrieved November 11, 2021)

[0071] In addition, the least square error E was also calculated when the data of (the number of 0201 chips attached at the number of structures satisfying other birth and death diameters - 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 The range where electronic components are unlikely to adhere was confirmed by combining the condition that E((count0201-B25_D25)-Sdq) is smaller than other least square errors E and 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.

[0072] (Comparative reference example) The evaluation results of the resin substrates of the above-mentioned Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-8 are shown on the graph, with the root mean square slope Sdq on the vertical axis and the number of structures (per unit area 1 mm2) that satisfy the birth diameter ≦ 10 μm and death diameter ≧ 10 μm in persistent homology. 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 was obtained with the adhesion of electronic components.

[0073] That is, the present disclosure provides the following inventions. [1] An electronic component storage case comprising 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 inner wall surfaces of the pair of main walls satisfy the following conditions (i) and (ii): (i) The root mean square slope Sdq is greater than or equal to 0.76 and less than or equal to 1.47. (ii) The structure that satisfies the birth diameter ≦ 25 μm and the death diameter ≧ 25 μm in the persistent homology is 2 There are 150 or less per [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 [1], wherein the resistance of the electronic component storage case is less than Ω / □. [3] An electronic component storage body comprising the electronic component storage case according to [1] or [2] and a plurality of electronic components stored in the case body. [Explanation of symbols]

[0074] 1 … Electronic parts storage case 2 … Case body 3 … Outlet 4 … Slide shutter 5...Operation unit

Claims

1. An electronic component storage case including a case body in which a plurality of electronic components are stored in a bulk state, The electronic component storage case according to claim 1, wherein the case body has a flat box shape having 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 greater than or equal to 0.76 and less than or equal to 1.

47. (ii) A structure that satisfies the birth diameter ≦ 25 μm and the death diameter ≧ 25 μm in the persistent homology is 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. The electronic component storage case according to claim 1 or 2, and a plurality of electronic components housed in the case body.

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