Electronic component

Abstract

This electronic component (1) is provided with: a ceramic element body (2) having main surfaces (2a, 2a); electrode parts (3, 3) provided on each of the main surfaces (2a, 2a); lead terminals (4, 4) electrically connected to each of the electrode parts (3, 3); and an exterior resin (5) provided so as to cover the base end portions of the ceramic element body (2), the electrode sections (3, 3), and the lead terminals (4, 4), the exterior resin (5) being formed into a double-layer structure comprising an inner layer (11) and an outer layer (12), the colors of which differ from each other, the color of the inner layer (11) being that of the outer layer (12) being that of the outer layer (12) being that of the inner layer (11). In an L * a * b * color space S, each of which has a value of 0-255, a color difference of 150 or less with respect to an interval color having the maximum color difference with respect to the color of the outer layer (12).

Description

Technical Field

[0001] The present disclosure relates to electronic components such as capacitors. Background Art

[0002] As a conventional electronic component, there is a ceramic electronic component described in Japanese Patent Application Laid-Open No. 2001-274037. This conventional electronic component comprises a ceramic body, external electrodes provided on the ceramic body, lead terminals connected to the external electrodes, and an exterior resin covering the ceramic body and the external electrodes. Summary of the invention

[0003] In electronic components such as those described above, fine holes (hereinafter referred to as "pin holes") are sometimes formed in the outer layer resin during the manufacturing process. There are many unclear parts in the formation mechanism of pinholes, and it is currently difficult to suppress the formation of pinholes. Therefore, a visual inspection is performed on the manufactured electronic components, and a good / defective product is determined based on the formation state of the pinholes in the outer resin. In the appearance inspection, for example, if the pinhole cannot be confirmed, it is judged as a good product. If the depth of the pinhole can be confirmed, it is judged as a good product within the limit. If the depth of the pinhole cannot be confirmed, it is judged as a defective product from the perspective of ensuring the reliability of the electronic component.

[0004] In the appearance inspection of electronic components, for example, AI image inspection using a good product model can be used. In this method, for example, a good product model that optimizes the threshold of good products is generated only by learning good product data, and is used for good or bad judgment of appearance inspection. However, in this method, since the sum of the color difference between the input image and the output image is set as the abnormality, there is a tendency to be difficult to obtain sufficient judgment accuracy for abnormalities with small areas or abnormalities with small color differences from good product images. Since pinholes in electronic components belong to both the above-mentioned abnormalities with small areas and abnormalities with small color differences from good product images, a technology that can improve inspection accuracy is desired.

[0005] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide an electronic component capable of performing a quality determination with high accuracy based on the formation state of a pinhole.

[0006] The main contents of this disclosure are as follows.

[0007] [1] An electronic component, comprising: a ceramic body having a pair of electrode portions on each of a pair of main surfaces; a pair of electrode portions provided on each of the pair of main surfaces; a pair of lead terminals electrically connected to each of the pair of electrode portions; and an outer resin provided to cover the ceramic body, the pair of electrode portions, and base end portions of the pair of lead terminals, the outer resin being formed into a double-layer structure consisting of an inner layer and an outer layer having different colors, the color of the inner layer being a color having a color difference of within 150 from an interval color having a maximum color difference with respect to the color of the outer layer in an L*a*b* color space having values ​​of 0 to 255.

[0008] In this electronic component, the outer resin is composed of an inner layer and an outer layer, and the color of the inner layer is defined based on the interval color of the color farthest from the outer layer in the L*a*b* color space. In this electronic component, since there is a sufficient color difference between the outer layer and the inner layer, the formation state of the pinhole can be confirmed by calculating the color far from the outer layer in image processing. At this time, the color difference of the color of the inner layer relative to the interval color is within 150, so that the AUC, which is an evaluation index related to binary classification, can be close to 1. Therefore, in this electronic component, the quality judgment can be carried out with high accuracy based on the formation state of the pinhole.

[0009] [2] The electronic component according to [1], wherein the color of the inner layer is a color that is within 100 color differences from the interval color. In this case, AUC, which is an evaluation index related to binary classification, can be reliably made close to 1. Therefore, it is possible to perform quality determination based on the formation state of the pinhole with higher accuracy.

[0010] [3] The electronic component according to claim [1] or [2], wherein the color of the outer layer is a color that has a color difference of 50 or less from a vertex color located at a vertex of the L*a*b* color space. In this case, the color difference between the color of the outer layer and the interval color can be sufficiently ensured, and as a result, the color difference between the outer layer and the inner layer can be easily ensured. Therefore, the accuracy of the good / bad judgment based on the formation state of the pinhole can be further improved. In addition, the freedom of selection of the resin material used for the inner layer can be ensured.

[0011] [4] An electronic component according to any one of claims [1] to [3], wherein the color of the outer layer is a color that has a color difference of 50 or less from an edge color located at an edge of the L*a*b* color space. In this case, the color difference between the color of the outer layer and the interval color can be sufficiently ensured, and as a result, the color difference between the outer layer and the inner layer can be easily ensured. Therefore, the accuracy of the good / bad judgment based on the formation state of the pinhole can be further improved. In addition, the freedom of selection of the resin material used for the inner layer can be ensured.

[0012] [5] An electronic component according to any one of claims [1] to [4], wherein, in the outer resin, at least in a portion closer to the pair of lead terminals than the ceramic body, the thickness of the inner layer is greater than the thickness of the outer layer. In the outer layer resin, there is a tendency that pinholes are more likely to appear in a portion closer to the pair of lead terminals than the ceramic body. By making the thickness of the inner layer in this portion greater than the thickness of the outer layer, the inner layer is more likely to be exposed from the outer layer in the case of a pinhole that reaches a depth such as the lead terminal, thereby ensuring the accuracy of the quality judgment.

[0013] [6] An electronic component according to any one of claims [1] to [4], wherein, in the outer resin, at least in a portion closer to the pair of lead terminals than the ceramic body, the thickness of the outer layer is greater than the thickness of the inner layer. In the outer resin layer, there is a tendency for pinholes to be more likely to appear in a portion closer to the pair of lead terminals than the ceramic body. By making the thickness of the outer layer in this portion greater than the thickness of the inner layer, the inner layer is less likely to be exposed from the outer layer in the case of pinholes that do not reach the depth of the lead terminals or the ceramic body, thereby preventing good products within the limit from being judged as defective products. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic cross-sectional view of an electronic component according to an embodiment of the present disclosure when viewed from the front.

[0015] Figure 2 Observed from the side Figure 1 A schematic cross-sectional view of a case of electronic components is shown.

[0016] Figure 3 This is a diagram showing the relationship between the color of the outer layer and the color of the inner layer in the L*a*b* color space.

[0017] Figure 4 Yes Figure 1 and Figure 2 A flowchart of an example of appearance inspection of electronic components shown in FIG.

[0018] Figure 5 , (a) and (b) are graphs showing the relationship between the ROC curve and the AUC.

[0019] Figure 6 , (a) and (b) are graphs showing the relationship between the ROC curve and the AUC.

[0020] Figure 7 , (a) and (b) are graphs showing the relationship between the ROC curve and the AUC.

[0021] Figure 8, (a) and (b) are graphs showing the evaluation results of AUC of the appearance inspection of the electronic component of Example 1.

[0022] Fig. 9 , (a) and (b) are graphs showing the evaluation results of AUC of the appearance inspection of the electronic component of Example 2.

[0023] Fig.10 In the drawings, (a) and (b) are schematic cross-sectional views showing enlarged main parts of electronic components according to modified examples.

[0024] Fig.11 In the drawings, (a) and (b) are schematic cross-sectional views showing enlarged main parts of electronic components according to other modified examples. DETAILED DESCRIPTION

[0025] Hereinafter, preferred embodiments of an electronic component according to one aspect of the present disclosure will be described in detail with reference to the accompanying drawings.

[0026] Figure 1 This is a schematic cross-sectional view of an electronic component according to an embodiment of the present disclosure when viewed from the front. Figure 2 Observed from the side Figure 1 A schematic cross-sectional view of a case of electronic components is shown. Figure 1 and Figure 2 The electronic component 1 shown is configured as a radial lead type single plate capacitor. The electronic component 1 is mounted on a substrate of an electronic device using a bonding material such as solder. The electronic component 1 is configured to include a ceramic element 2, a pair of electrode portions 3, 3, a pair of lead terminals 4, 4, and an outer resin 5. The surface of the disk-shaped portion 5A of the outer resin 5, which will be described later, in the direction in which the lead terminal 4 extends is a mounting surface R when mounted on the substrate.

[0027] In the following description, for the sake of convenience, the mounting surface R is set to the bottom, and the opposite surface of the mounting surface R is set to the top. In addition, the normal direction of the mounting surface R is set to the height direction, the relative direction of the main surfaces 2a, 2a of the ceramic element body 2 is set to the thickness direction, and the direction orthogonal to the normal direction of the mounting surface R and the relative direction of the main surfaces 2a, 2a is set to the width direction. When viewed from the normal direction of the mounting surface R, the thickness direction, and the width direction, the electronic component 1 is configured to have bilateral symmetry.

[0028] The ceramic body 2 is composed of, for example, a dielectric element. The dielectric element is composed of, for example, a dielectric material (BaTiO 3 System, Ba(Ti, Zr)O 3 System, or (Ba, Ca)TiO 3 It is composed of a sintered body of a ceramic green sheet (such as a dielectric ceramic).

[0029] The overall shape of the ceramic body 2 is a disc or a flat cylindrical shape. The ceramic body 2 has: a pair of circular main surfaces 2a, 2a facing each other, and a peripheral surface 2b connecting the main surfaces 2a, 2a. The ceramic body 2 is arranged in a manner that the relative direction of the main surfaces 2a, 2a intersects (is perpendicular to) the normal direction of the mounting surface R.

[0030] The electrode parts 3, 3 are respectively provided on the main surfaces 2a, 2a. The electrode part 3 is provided, for example, in a manner covering the entire main surface 2a. One side of the electrode part 3 is a + electrode, and the other side is a - electrode. The electrode part 3 is composed of a sintered layer of an electrode paste containing a metal or glass. As the metal, for example, Cu, Ni, Ag, etc. can be used.

[0031] Lead terminals 4, 4 are electrically connected to electrode portions 3, 3, respectively. Lead terminal 4 connected to the + electrode is a + terminal, and lead terminal 4 connected to the - electrode is a - terminal. For the connection between lead terminal 4 and electrode portion 3, for example, a bonding material such as solder can be used. Examples of the constituent material of lead terminal 4 include phosphor bronze, stainless steel, Ni-Fe alloy (for example, 42 alloy), etc. A metal plating layer such as Ni plating layer and Sn plating layer may also be provided on the surface of lead terminal 4. The plating layer may also be either a single layer or a multilayer.

[0032] The lead terminal 4 includes a connection portion 4A connected to the electrode portion 3 on the main surface 2a of the ceramic body 2, and a hanging portion 4B continuous with the connection portion 4A and protruding toward the mounting surface R. Figure 1 As shown in the figure, the connection portion 4A of one lead terminal 4 extends in the in-plane direction of the electrode portion 3 from the vicinity of the center of the ceramic element body 2 toward one outer side in the width direction when viewed from the relative direction of the main surfaces 2a, 2a. The connection portion 4A of the other lead terminal 4 extends in the in-plane direction of the electrode portion 3 from the vicinity of the center of the ceramic element body 2 toward the other outer side in the width direction when viewed from the relative direction of the main surfaces 2a, 2a. The hanging portion 4B extends linearly from the top end of the connection portion 4A along the normal direction of the mounting surface R when viewed from the relative direction of the main surfaces 2a, 2a.

[0033] like Figure 2 As shown in FIG. 1 , a kinked portion 4C having a kink process is provided in the middle of the hanging portion 4B. Kink processing refers to a bending process performed for the purpose of facilitating temporary fixing of the electronic component 1 to the substrate. The hanging portion 4B is bent toward the center side in the thickness direction at a position lower than the ceramic body 2 by the kink portion 4C. When the electronic component 1 is viewed from the width direction, the positions of the hanging portions 4B, 4B on the front end side in the thickness direction are aligned with each other compared to the kink portion 4C of the lead terminals 4, 4.

[0034] The exterior resin 5 is a component that protects the main parts such as the ceramic body 2. The exterior resin 5 is provided so as to cover the ceramic body 2 and the base end parts of the lead terminals 4, 4. In the present embodiment, the exterior resin 5 covers the base end parts of the lead terminals 4, 4 in a manner including the kink part 4C. That is, in the present embodiment, in the height direction of the electronic component 1, the kink part 4C is located between the ceramic body 2 and the mounting surface R, and is buried in the exterior resin 5.

[0035] The outer coating resin 5 is made of, for example, an insulating resin material. The outer coating resin 5 is formed, for example, by a dipping method or injection molding using a mold. The outer coating resin 5 has a shape that roughly corresponds to the shape of the ceramic body 2, the electrode portions 3, 3, and the lead terminals 4, 4. The outer coating resin 5 has a disk-shaped portion 5A that covers the ceramic body 2 and the electrode portions 3, 3, and a pair of protruding portions 5B, 5B that protrude below the disk-shaped portion 5A and cover the base end portions of the lead terminals 4, 4.

[0036] The outer resin 5 is formed into a double-layer structure consisting of an inner layer 11 and an outer layer 12 of different colors. The inner layer 11 integrally covers the ceramic body 2, the electrode parts 3, 3 and the lead terminals 4, 4. The outer layer 12 is formed in a manner to cover the entire inner layer 11, and integrally covers the ceramic body 2, the electrode parts 3, 3 and the lead terminals 4, 4 together with the inner layer 11. Examples of the resin material constituting the inner layer 11 include epoxy resins, silicon dioxide and the like. Examples of the resin material constituting the inner layer 12 are the same as those of the inner layer 11, and examples thereof include epoxy resins, silicon dioxide and the like. Figure 1 and Figure 2 In the example, the thickness of the inner layer 11 and the thickness of the outer layer 12 are consistent and equal to each other regardless of the location.

[0037] The pinholes P of the exterior resin 5 are detected with high accuracy by image processing (see Fig.10 (a) and Fig.11 From the perspective of (b)), the colors of the inner layer 11 and the inner layer 12 are different. The color of the inner layer 11 and the color of the outer layer 12 can be expressed using the L*a*b* color space. The L*a*b* color space is a complementary color space represented by an L* axis representing brightness, an a* axis representing chromaticity, and a b* axis. The L*a*b* color space is standardized by the International Commission on Illumination (CIE) and adopted by JIS (JIS Z8781-4) in Japan.

[0038] Figure 3The L*a*b* color space S shown is a three-dimensional orthogonal space in which L*, a*, and b* take values ​​of 0 to 255, respectively. The smaller the value of L*, the darker the color, and the larger the value of L*, the brighter the color. The closer the values ​​of a* and b* are to the edge of the L*a*b* color space S, the brighter the color, and the closer the values ​​of a* and b* are to the center of the L*a*b* color space S, the darker the color. As shown in the following formula (1), the difference (color difference) ΔE between two colors in the L*a*b* color space S is expressed as the distance between two points in the space.

[0039]

Mathematical formula 1

[0040]

[0041] In this embodiment, the color of the inner layer 11 is a color that has a color difference of less than 150, preferably less than 100, from the interval color that has the maximum color difference with respect to the color of the outer layer 12 in the L*a*b* color space S. For example, Figure 3 As shown, when the L*a*b* coordinate of the point Kg representing the color of the outer layer 12 is [200, 117, 115], the L*a*b* coordinate of the point Kr representing the interval color having the maximum color difference with respect to the color of the outer layer 12 is [0, 255, 255] (the color difference between the point Kg and the point Kr can be estimated to be about 280 according to formula (1). In this case, the color of the inner layer 11 is selected from the colors in the region R1 within 150, preferably within 100, of the color difference with the point Kr representing the interval color.

[0042] When selecting the color of the inner layer 11, the color of the outer layer 12 may be selected from colors that are within a color difference of 50 from the color of the vertex Kp (vertex color) of the L*a*b* color space S. In addition, the color of the outer layer 12 may be selected from colors that are within a color difference of 50 from the color of the edge Kh (edge ​​color) of the L*a*b* color space S. In the present embodiment, the color of the outer layer 12 may be selected from colors that are within a color difference of 50 from the vertex color or within a color difference of 50 from the edge color in the region R2.

[0043] Figure 4 FIG. 1 is a flowchart showing an example of visual inspection of electronic components. Figure 4 As shown, when the appearance inspection of the electronic component 1 is performed, first, the detection color range of the image processing is set based on the color of the inner layer 11 (step S01). The detection color range can be set to, for example, a range including the color of the inner layer 11. In this embodiment, since the color of the inner layer 11 is set within a region R1 within which the color difference with the point Kr representing the interval color is within 150, preferably within 100, the region R1 is set as the detection color range, for example.

[0044] After setting the detection color range, the appearance of the electronic component 1 is photographed using an imaging device such as a camera (step S02). Here, the front and back (two sides in the thickness direction) of the electronic component 1 are photographed respectively, and image data is acquired based on the photographing results. When the appearance inspection is performed on multiple electronic components 1, the multiple electronic components 1 can also be transported by a conveying means such as a conveyor belt and photographed.

[0045] Next, the number of pixels of the color within the detection color range among the pixels included in the image data of the table of the obtained electronic component 1 is calculated (step S03). When calculating the number of pixels, for example, OpenCV (Open Source Computer Vision Library) of Python is used to convert the color of each pixel into a coordinate in the L*a*b* color space. Then, the total number of pixels of the color within the detection color range in the image data of the table of the obtained electronic component 1 is calculated.

[0046] Next, it is determined whether the number of pixels of the color in the detection color range is below the threshold value (step S04). As described above, the color in the detection color range is set to the color of the inner layer 11 and the color near it. In the case where the pinhole P is not formed in the outer resin 5, only the outer layer 12 is exposed on the surface of the electronic component 1, and therefore, the pixels of the color in the detection color range are not included in the image data of the electronic component 1. On the other hand, in the case where the pinhole P is formed in the outer resin 5, the inner layer 11 is exposed at the position of the pinhole P. Therefore, it is possible to determine whether the pinhole P is formed in the outer resin 5 based on the number of pixels of the color in the detection color range.

[0047] In step S04, when the number of pixels of the color in the detected color range is below the threshold, the electronic component 1 is determined to be a good product (step S05). When the number of pixels of the color in the detected color range exceeds the threshold, the electronic component 1 is determined to be a defective product (step S06). In step S05, a further threshold for determining good products and good products within the limit can also be set. In this case, for example, the following determination can be made: if the number of pixels of the color in the detected color range is 0, it is determined to be a good product; if it is above 1 and below 4, it is determined to be a good product within the limit; if it is above 5, it is determined to be a defective product.

[0048] In addition, you can also combine Figure 4 The appearance inspection shown in the figure and the AI ​​image inspection using the good product model. In the AI ​​image inspection, for example, only by learning the good product data, a good product model that optimizes the threshold of good products is generated, and the sum of the color difference between the input image and the output image is used as the abnormality to implement the good / failure judgment. Figure 4In the case of the appearance inspection and AI image inspection shown in the figure, the AI ​​image inspection may be performed first, and the electronic components 1 judged as good products may be subjected to the AI ​​image inspection. Figure 4 Instead, you can also first perform Figure 4 In the appearance inspection shown, the electronic components 1 judged to be good products are subjected to AI image inspection.

[0049] Next, the electronic component 1 is subjected to Figure 4 An evaluation test for determining performance in the case of the appearance inspection shown will be described.

[0050] In this evaluation test, 20 images of good products were prepared for the electronic components of Example 1 and Example 2, 10 of which were directly used as good product images, and the remaining 10 were used as defective product images obtained by overlapping virtual pinhole images of colors with L*a*b* coordinates of [0, 255, 255] (equivalent to the above-mentioned interval colors). And, with the color [0, 255, 255] as the reference, the number of pixels with a color difference below the threshold from the color was used as the abnormality to calculate the AUC (Area Under ROC Curve).

[0051] AUC is an evaluation index for binary classification such as good / bad judgment, and has a value ranging from 0 to 1. When good / bad classification can be completely achieved, the AUC value is 1, and when good / bad classification is random, the AUC value is 0.5. AUC is a value determined based on the ROC (Receiver Operating Characteristics) curve, and is specifically represented by the area below the ROC curve.

[0052] The ROC curve is represented by a two-dimensional plane with the horizontal axis being the false positive rate (FPR) and the vertical axis being the true positive rate (TPR). The false positive rate is the ratio of the number of good products correctly judged as good products relative to the total number of good products. The true positive rate is the ratio of all defective products that are mistakenly judged as good products. Figure 5 (a) is a diagram showing an example of the distribution of good and defective products. Figure 5 As shown in (a) of FIG. 1 , if the threshold value for quality judgment is changed, the true positive rate and the false positive rate will change. Figure 5 (b) is a graph showing the tendency of the ROC curve in conventional binary classification. Figure 5 The true positive rate and false positive rate of threshold A, threshold B and threshold C shown in (a) are equivalent to Figure 5 (b) shows points A, B and C of the ROC curve.

[0053] like Figure 6As shown in (a), when the distribution of good and defective products is exactly the same, that is, when the classification of good and bad products is random, as shown in Figure 6 As shown in (b), the ROC curve is a straight line connecting the coordinates [0, 0] and [1, 1] with a slope of 1. In this case, the AUC represented by the area below the ROC curve is 0.5. Figure 7 As shown in (a), when the distribution of good products and defective products is completely separated, that is, when good products and defective products can be completely classified, as shown in Figure 7 As shown in (b), the ROC curve is a line that linearly connects the coordinates [0, 0] and [0, 1], and linearly connects the coordinates [0, 1] and [1, 1]. In this case, the AUC represented by the area below the ROC curve is 1.0.

[0054] Figure 8 (a) and Figure 8 (b) is a graph showing the evaluation results of AUC of the appearance inspection of the electronic components of Example 1. Figure 8 As shown in (a), in Example 1, the color coordinates of the outer layer are set to light blue [200, 117, 115]. For the color coordinates of the outer layer, the color of the outer layer of the sample is randomly extracted from 5 locations, and the calculation is performed based on the average value of the color coordinates of the extracted locations. In this case, the color coordinates of the interval color having the largest color difference with respect to the color of the outer layer are brown [0, 255, 255].

[0055] exist Figure 8 In (a), four colors, brown [0, 255, 255], red brown [58, 197, 197], dark brown [87, 168, 168], and gray [115, 140, 140], are extracted as the colors of the inner layer. The color differences between these inner layer colors and the interval colors are 0, 100, 150, and 200, respectively. When the color difference is 0, 100, and 150, the AUC value is 1.00, while when the color difference is 200, the AUC value is 0.79.

[0056] Figure 8 (b) means including Figure 8 The result of (a) is a graph showing the calculation results of AUC in the range where the color difference between the inner layer color and the interval color is greater than 0 and less than 400. Figure 8As shown in (b), it can be seen that: in the range of color difference of 0 or more and 154 or less, the AUC value is maintained at 1.00, while in the range of color difference exceeding 154, the AUC value decreases sharply and fluctuates in the range of 0.1 to 0.7. From this result, it can be confirmed that by setting the color difference between the color of the inner layer and the interval color to within 150, preferably within 100, the AUC value of the appearance inspection is 1.00, and the quality judgment based on the formation state of the pinhole can be performed with high accuracy.

[0057] Fig. 9 (a) and Fig. 9 (b) is a graph showing the evaluation results of AUC of the appearance inspection of the electronic components of Example 2. Fig. 9 As shown in (a), in Example 1, the color coordinates of the outer layer are dark blue [92, 167, 52]. As for the color coordinates of the outer layer, the color of the outer layer of the sample is randomly extracted from 5 places in the same manner as in Example 1, and the calculation is performed based on the average value of the color coordinates of each extracted part. In this case, the color coordinates of the interval color having the largest color difference with respect to the color of the outer layer are bright green [255, 0, 255].

[0058] exist Fig. 9 In (a), four colors, bright green [255, 0, 255], green [197, 58, 197], dark green [168, 87, 168], and gray [140, 115, 140], are extracted as the inner layer colors. The color differences between these inner layer colors and the interval colors are 0, 100, 150, and 200, respectively. When the color difference is 0, 100, and 150, the AUC value is 1.00, while when the color difference is 200, the AUC value is 0.31.

[0059] Fig. 9 (b) means including Fig. 9 The result of (a) is a graph showing the calculation results of AUC in the range where the color difference between the inner layer color and the interval color is greater than 0 and less than 400. Fig. 9 As shown in (b), it can be seen that: in the range of color difference of 0 or more and 168 or less, the AUC value is maintained at 1.00, while in the range of color difference exceeding 168, the AUC value decreases sharply and fluctuates in the range of 0.1 to 0.8. From this result, it can be confirmed that, similarly to Example 1, by setting the color difference between the color of the inner layer and the interval color to within 150, preferably within 100, the AUC value of the appearance inspection is 1.00, and the quality judgment based on the formation state of the pinhole can be performed with high accuracy.

[0060] As described above, in the electronic component 1, the exterior resin 5 is composed of the inner layer 11 and the outer layer 12, and the color of the inner layer 11 is defined based on the interval color of the color farthest from the outer layer 12 in the L*a*b* color space S. In the electronic component 1, there is a sufficient color difference between the outer layer 12 and the inner layer 11, so that the formation state of the pinhole P can be confirmed by calculating the color of the color farthest from the outer layer 12 in the image processing. At this time, the color difference of the color of the inner layer 11 with respect to the interval color is within 150, so that the AUC, which is an evaluation index related to binary classification, can be close to 1. Therefore, in the electronic component 1, the quality determination based on the formation state of the pinhole P can be performed with high accuracy.

[0061] In this embodiment, the color of the inner layer 11 is a color that is within 100 of the color difference of the interval color. In this case, AUC, which is an evaluation index related to binary classification, can be made closer to 1 more reliably. Therefore, the quality determination based on the formation state of the pinhole P can be performed more accurately.

[0062] In the present embodiment, the color of the outer layer 12 is a color whose color difference with the vertex color located at the vertex Kp of the L*a*b* color space S is within 50. In addition, in the present embodiment, the color of the outer layer 12 is a color whose color difference with the edge color located at the edge Kh of the L*a*b* color space S is within 50. According to this method, the color difference between the color of the outer layer 12 and the interval color can be sufficiently ensured, and as a result, the color difference between the outer layer 12 and the inner layer 11 can be easily ensured. Therefore, the accuracy of the good or bad judgment based on the formation state of the pinhole P can be further improved. In addition, the freedom of selection of the resin material used for the inner layer 11 can be ensured.

[0063] For example, in the above embodiment, the thickness of the inner layer 11 and the outer layer 12 in the outer resin 5 is consistent and equal to each other regardless of the location, but it may also be possible, for example, Fig.10 As shown in (a) of FIG. 1 , in the exterior resin 5 , at least in a portion W closer to the pair of lead terminals 4 , 4 than the ceramic element body 2 , the thickness of the inner layer 11 is greater than the thickness of the outer layer 12 .

[0064] The portion W closer to the pair of lead terminals 4, 4 than the ceramic body 2 is a region from the lowest point of the peripheral surface 2b of the ceramic body 2 to the tip of the portion covering the base end of the lead terminals 4, 4 (see Figure 1 and Figure 2 That is, the portion W includes: a portion of the disk-shaped portion 5A of the exterior resin 5 from the lowest point of the peripheral surface 2b of the ceramic element body 2 to the mounting surface R, and a pair of protruding portions 5B, 5B.

[0065] In the outer layer resin 5, there is a tendency that pinholes P are more likely to appear in a portion W closer to the pair of lead terminals 4, 4 than the ceramic element body 2. By making the thickness of the inner layer 11 of the portion W larger than the thickness of the outer layer 12, as shown in FIG. Fig.10 As shown in (b), for example, in the case of a pinhole P as deep as the lead terminal 4, the inner layer 11 is easily exposed from the outer layer 12, and the accuracy of the quality determination can be guaranteed. This is also the case when a pinhole P is formed as deep as the ceramic body 2.

[0066] In addition, for example, Fig.11 As shown in (a), in the exterior resin 5, at least in a portion W closer to the pair of lead terminals 4, 4 than the ceramic element body 2, the thickness of the outer layer 12 may be greater than the thickness of the inner layer 11. In this case, Fig.11 As shown in (b), in the pinhole P that does not reach the lead terminals 4, 4 or the ceramic body 2, the inner layer 11 is unlikely to be exposed from the outer layer 12, so that it is possible to suppress the judgment of good products within the limit as defective products.

[0067] In adopting Fig.10 (a) and Fig.11 In the case of the structure (a), in the outer resin 5, the thickness of the inner layer 11 and the outer layer 12 may have the above relationship only in at least the portion W closer to the pair of lead terminals 4, 4 than the ceramic body 2, or the thickness of the inner layer 11 and the outer layer 12 may have the above relationship in the entire outer resin 5 including the portion W. The thickness of the inner layer 11 and the outer layer 12 may have the above relationship in the portion W and a part of the portion other than the portion W.

Claims

1. An electronic component, wherein: have: A ceramic body having a pair of main surfaces; a pair of electrode portions provided on each of the pair of main surfaces; a pair of lead terminals electrically connected to each of the pair of electrode portions; and an outer resin provided so as to cover the ceramic body, the pair of electrode portions, and the base end portions of the pair of lead terminals, The outer resin is formed into a double-layer structure consisting of an inner layer and an outer layer of different colors. The inner color is a color whose color difference with respect to the outer color is within 150 from an interval color having the largest color difference with respect to the outer color in an L*a*b* color space having values ​​of 0 to 255.

2. The electronic component according to claim 1, wherein The color of the inner layer is a color that has a color difference of less than 100 from the interval color.

3. The electronic component according to claim 1 or 2, wherein: The color of the outer layer is a color whose color difference with the vertex color located at the vertex of the L*a*b* color space is within 50.

4. The electronic component according to any one of claims 1 to 3, wherein The color of the outer layer is a color whose color difference with the edge color located at the edge of the L*a*b* color space is within 50.

5. The electronic component according to any one of claims 1 to 4, wherein In the exterior resin, at least in a portion closer to the pair of lead terminals than the ceramic element body, the thickness of the inner layer is greater than the thickness of the outer layer.

6. The electronic component according to any one of claims 1 to 4, wherein In the exterior resin, at least in a portion closer to the pair of lead terminals than the ceramic element body, the thickness of the outer layer is greater than the thickness of the inner layer.

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