Circuit board and electronic control device

Abstract

This circuit board comprises: a substrate body, a first electronic component; a contact prevention component; and a lid-equipped electronic component. The height to which the contact prevention component protrudes from the mounting surface of the first electronic component and the contact prevention component is set higher than the height to which the lid-equipped electronic component protrudes. A first upper end portion of the lid-equipped electronic component on the first electronic component side is contained in a space that is formed by the mounting surface and a line that connects the mounting end portions on the mounting surface side of the contact prevention component from the upper end portion of the first electronic component. A second upper end portion of the lid-equipped electronic component on the contact prevention component side is contained in a space that is formed by the mounting surface and a line that connects the mounting end portions on the mounting surface side of the first electronic component from the upper end portion of the contact prevention component.

Description

Circuit board and electronic control unit

[0001] The present invention relates to a circuit board and an electronic control device.

[0002] Automobiles are equipped with electronic control units (ECs) that have electronic components that control the vehicle. In recent years, to realize high-performance driving assistance systems, such as braking systems that avoid collisions and autonomous driving, ECs installed in vehicles are required to have high computational performance. Therefore, ECs often incorporate quartz crystal units or crystal oscillators that enable high-speed, stable signal synchronization. Electronic components, such as ceramic packaged products like quartz crystal units, have a lid on top. Hereinafter, such electronic components are referred to as lidded electronic components. Furthermore, to prevent the lid on top from coming off due to contact during the inspection process, it is necessary to protect the lidded electronic components from external stress.

[0003] One such technique is described in, for example, Patent Document 1. Patent Document 1 describes a technique in which, on a circuit board on which multiple electronic components are mounted, an electronic component to be protected is positioned near another electronic component that is taller than the other electronic components. In this case, the electronic component to be protected is positioned so that it is completely contained within a space formed by a point on the electronic component on the electronic component side, the mounting surface of the circuit board, the edge of the circuit board, and the plane that contacts the electronic component at its upper part.

[0004] Japanese Patent Application Laid-Open No. 2002-43715

[0005] However, while the technology described in Patent Document 1 can protect electronic components from stresses from above that are perpendicular to the substrate plane, it cannot protect electronic components from stresses from the sides that are parallel to the substrate plane. As a result, with the technology described in Patent Document 1, there is a risk that the lid of the electronic component may come off due to stress during an inspection process, etc.

[0006] In consideration of the above problems, an object of the present invention is to provide a circuit board and an electronic control device that can protect electronic components with a lid from external stress.

[0007] To solve the above problems and achieve the object, a circuit board includes a board body, a first electronic component mounted on the mounting surface of the board body, a contact-preventing component, and a capped electronic component. The contact-preventing component is mounted on the mounting surface of the board body and is located closer to the end of the board body than the first electronic component. The capped electronic component is mounted on the mounting surface of the board body and is located between the first electronic component and the contact-preventing component. The protruding heights of the first electronic component and the contact-preventing component from the mounting surface are set higher than the protruding height of the capped electronic component. Furthermore, a first upper end of the capped electronic component facing the first electronic component is accommodated within a space formed on the mounting surface by a line connecting the upper end of the first electronic component to the mounting end of the contact-preventing component on the mounting surface. Furthermore, a second upper end of the capped electronic component facing the contact-preventing component is accommodated within a space formed on the mounting surface by a line connecting the upper end of the contact-preventing component to the mounting end of the first electronic component on the mounting surface.

[0008] The electronic control device also includes a circuit board and a connector, and the circuit board described above is used as the circuit board.

[0009] According to the circuit board and electronic control device having the above configuration, the covered electronic component can be protected from external stress.

[0010] Fig. 5A is an external view showing a circuit board of an electronic control device according to a first embodiment; Fig. 5B is a cross-sectional view showing a circuit board according to a first embodiment; Fig. 5C is a cross-sectional view showing a conventional circuit board; Fig. 5D is a plan view showing a circuit board according to a first embodiment; Fig. 5E is a front view showing a state in which a connector is mounted on the circuit board according to the first embodiment, Fig. 5F is a rear view; Fig. 5G is a cross-sectional view showing a circuit board according to a second embodiment;

[0011] Hereinafter, embodiments of an electronic control device and a circuit board will be described with reference to Figures 1 to 6. Note that common members in each figure are given the same reference numerals.

[0012] 1. First Embodiment First, the configuration of an electronic control device and a circuit board according to a first embodiment (hereinafter referred to as "this embodiment") will be described with reference to Figures 1 to 5B. Figure 1 is a plan view showing the board of the electronic control device, and Figure 2 is a cross-sectional view showing the electronic control device.

[0013] 1 and 2 is a circuit board of an electronic control device that is mounted on an automobile and controls the automobile. As shown in Fig. 1 and 2, the circuit board 100 includes a flat board body 10, a first electronic component 1, a second electronic component 2, and a third electronic component 3.

[0014] The first electronic component 1, the second electronic component 2, and the third electronic component 3 are mounted on the mounting surface 10b of the substrate body 10. The first electronic component 1 and the second electronic component 2 are electronic components that have a lower failure rate due to external stress than the third electronic component 3, which will be described later. The first electronic component 1 and the second electronic component 2 may be, for example, a capacitor or an SOC (System On a Chip). In this example, an SOC is used as the first electronic component 1, and a capacitor or a dummy capacitor is used as the second electronic component 2.

[0015] The second electronic component 2, which represents a contact-preventing component, is arranged closer to the end 10a of the substrate body 10 than the first electronic component 1 and the third electronic component 3. The third electronic component 3 is arranged closer to the end 10a of the substrate body 10 than the first electronic component 1. The third electronic component 3 is also arranged near the first electronic component 1 and the second electronic component 2. Specifically, the third electronic component 3 is arranged between the first electronic component 1 and the second electronic component 2. In other words, the third electronic component 3 is arranged so as to be sandwiched between the first electronic component 1 and the second electronic component 2.

[0016] The third electronic component 3 is a lidded electronic component that has a higher failure rate due to external stress than the first electronic component 1 and the second electronic component 2. A ceramic package product such as a gyro sensor or a quartz crystal oscillator is used as the third electronic component 3. In this example, a quartz crystal oscillator is used as the third electronic component 3.

[0017] The protrusion heights of the first electronic component 1 and the second electronic component 2 from the mounting surface 10b are set to be higher than that of the third electronic component 3. Therefore, as shown in Fig. 2, the third electronic component 3 is accommodated within the space formed by the mounting surface 10b and an upper end line P1 connecting the upper end 1a of the first electronic component 1 and the upper end 2a of the second electronic component 2.

[0018] Fig. 3 is a cross-sectional view showing a conventional circuit board. As shown in Fig. 3, the conventional circuit board 200 has a first electronic component 1, a second electronic component 21, and a third electronic component 3, which is a lidded electronic component, mounted on a board body 10. The third electronic component 3 is disposed between the first electronic component 1 and the second electronic component 21. The second electronic component 21, which is mounted on the end 10a side of the board body 10, protrudes from the mounting surface 10b to a lower height than the third electronic component 3. The third electronic component 3 protrudes from the mounting surface 10b beyond the upper end 21a of the second electronic component 21.

[0019] Therefore, in the conventional circuit board 200, during an inspection process or the like, fingers, an inspection tool, or the like can come into contact with the third electronic component 3 from the end 10a side of the board body 10. As a result, there is a risk that the cover of the third electronic component 3 may come off due to external stress, causing damage to the third electronic component 3.

[0020] In contrast, in the circuit board 100, the first electronic component 1 and the second electronic component 2 are taller than the third electronic component 3, and the third electronic component 3 is contained within the space formed by the mounting surface 10b and the upper end line P1 connecting the upper end 1a of the first electronic component 1 and the upper end 2a of the second electronic component 2. This prevents fingers, inspection tools, and the like from coming into contact with the third electronic component from the end 10a side of the board body 10. This protects the third electronic component, which is a lidded electronic component, from external stress.

[0021] Furthermore, the first upper end 3a of the third electronic component 3 on the first electronic component 1 side is contained within the space formed by the mounting surface 10b and a line P2 connecting the upper end 1a of the first electronic component 1 to the mounting end 2b on the mounting surface 10b side of the second electronic component 2. This makes it possible to prevent fingers, an inspection jig, or the like from coming into contact with the first upper end 3a of the third electronic component 3 from the first electronic component 1 side.

[0022] Furthermore, the second upper end 3b of the third electronic component 3 on the second electronic component 2 side is contained within the space formed by the mounting surface 10b and a line P3 connecting the upper end 2a of the second electronic component 2 to the mounting end 1b on the mounting surface 10b side of the first electronic component 1. This makes it possible to prevent fingers, an inspection jig, or the like from coming into contact with the second upper end 3b of the third electronic component 3 from the second electronic component 2 side.

[0023] 4 is a plan view showing a circuit board 100 of this example. As shown in FIG. 4 , the circuit board 100 of this example has multiple second electronic components 2, 2 mounted on a board body 10. The spacing between the multiple second electronic components 2 is set narrow enough to prevent fingers, inspection tools, and the like from getting in between. The width of the first electronic component 1 in a direction parallel to the mounting surface 10b of the board body 10 is set longer than the width of the third electronic component 3. In addition, the combined length of the multiple second electronic components 2, 2 from one end 2c to the other end 2d in the width direction is set longer than the width of the third electronic component 3.

[0024] Here, a line extending parallel to the mounting surface 10b from one end 2c of each of the second electronic components 2, 2 toward the first electronic component 1 is referred to as a first line Q1. A line extending parallel to the mounting surface 10b from the other end 2d of each of the second electronic components 2, 2 toward the first electronic component 1 is referred to as a second line Q2. In this case, the third electronic component 3 is disposed between the first line Q1 and the second line Q2. That is, when the first electronic component 1, the second electronic component 2, and the third electronic component 3 are viewed from the end 10a of the board body 10 in a direction parallel to the mounting surface 10b, the third electronic component 3 is covered by the second electronic component 2. Therefore, the third electronic component 3 is housed in a space formed by the top line P1, the first line Q1, the second line Q2, and the mounting surface 10b shown in FIG. 2 .

[0025] In this way, the third electronic component 3 is arranged surrounded by the first electronic component 1 and the second electronic components 2, 2. As a result, the circuit board 100 of this example can prevent fingers, inspection tools, and the like from coming into contact with the third electronic component 3, and can protect the third electronic component, which is a lidded electronic component, from external stress.

[0026] In this example, a plurality of second electronic components 2 are mounted side by side, but the present invention is not limited to this, and the number of second electronic components 2 serving as contact prevention components may be only one. In this case, the length from one end 2 c to the other end 2 d in the width direction of one second electronic component 2 is set to be longer than the length of the third electronic component 3 in the width direction.

[0027] 5A and 5B show the state in which a connector is mounted on the circuit board 100 of this example, with FIG. 5A being a front view and FIG. 5B being a rear view. Here, if a quartz crystal resonator is used as the third electronic component 3, which is a capped electronic component, the third electronic component 3 is likely to be a noise source. Therefore, when mounting the connector 4, which is an analog component susceptible to noise, on the board main body 10, the connector 4 is mounted on the back surface opposite the mounting surface 10b on which the third electronic component 3 is mounted. In other words, the connector 4 and the third electronic component 3 are arranged perpendicular to each other with respect to the mounting surface 10b of the board main body 10. This suppresses the effect of noise from the third electronic component 3 on the connector 4. As a result, there is no need to provide EMC countermeasure components, enabling cost reduction.

[0028] The connector 4 is mounted on the circuit board 100 to form an electronic control device.

[0029] 2. Second Embodiment Next, a circuit board according to a second embodiment will be described with reference to Fig. 6. Fig. 6 is a cross-sectional view showing a circuit board according to the second embodiment.

[0030] The circuit board 100B according to the second embodiment differs from the circuit board 100 according to the first embodiment in that a ground is mounted on the circuit board 100B. Therefore, the protective member will be described here, and parts common to the circuit board 100 according to the first embodiment will be assigned the same reference numerals and will not be described again.

[0031] 6 , the circuit board 100B has a flat board body 10, a first electronic component 1, a second electronic component 2, a third electronic component 3, a signal ground 5, and a frame ground 6. The signal ground 5 and the frame ground 6 are mounted on the mounting surface 10b of the board body 10, similar to the first electronic component 1, the second electronic component 2, and the third electronic component 3. The signal ground 5 and the frame ground 6 are located closer to the end 10a of the board body 10 than the second electronic component 2.

[0032] The second electronic component 2 is also connected to the signal ground 5 and the frame ground 6. In this way, by connecting the second electronic component 2, which is a contact-preventing component, to various grounds mounted on the board main body 10, it is possible to improve resistance to electromagnetic noise and achieve EMC countermeasures. Furthermore, since the second electronic component 2, which is a contact-preventing component, also serves as a component for EMC countermeasures, it is possible to prevent an increase in the number of components and reduce the cost of manufacturing the circuit board 100B.

[0033] The other configurations are the same as those of the circuit board 100 according to the first embodiment, and therefore description thereof will be omitted. The circuit board 100B according to the second embodiment can also achieve the same effects as those of the circuit board 100 according to the first embodiment described above.

[0034] The present invention is not limited to the embodiments described above and shown in the drawings, and various modifications are possible within the scope of the invention as defined in the claims. It is also possible to replace a part of the configuration of one embodiment with a configuration of another embodiment, or to add a configuration of another embodiment to a configuration of one embodiment. Furthermore, it is also possible to add, delete, or replace a part of the configuration of another embodiment with another configuration.

[0035] In this specification, the words "parallel" and "orthogonal" are used, but these do not mean only "parallel" and "orthogonal" in the strict sense, but also include "parallel" and "orthogonal" and may also mean a "substantially parallel" or "substantially orthogonal" state within a range in which the functions can be exerted.

[0036] DESCRIPTION OF SYMBOLS 1...first electronic component, 1a...upper end, 1b...mounting end, 2...second electronic component (contact-preventing component), 2a...upper end, 2b...mounting end, 2c...one end, 2d...other end, 3...third electronic component (electronic component with lid), 3a...first upper end, 3b...second upper end, 4...connector, 5...signal ground, 6...frame ground, 10...board main body, 10a...end, 10b...mounting surface, 100, 100B...circuit board, P1...upper end line, P2, P3...line, Q1...first line, Q2...second line

Claims

1. A circuit board comprising: a board body; a first electronic component mounted on a mounting surface of the board body; a contact-prevention component mounted on the mounting surface of the board body and positioned at an end of the board body closer to the first electronic component; and a lidded electronic component mounted on the mounting surface of the board body and positioned between the first electronic component and the contact-prevention component, wherein a protruding height from the mounting surface of the first electronic component and the contact-prevention component is set higher than a protruding height of the lidded electronic component, a first upper end of the lidded electronic component on the first electronic component side is contained within a space formed on the mounting surface by a line connecting a top end of the first electronic component to a mounting end of the contact-prevention component on the mounting surface side, and a second upper end of the lidded electronic component on the contact-prevention component side is contained within a space formed on the mounting surface by a line connecting a top end of the contact-prevention component to a mounting end of the first electronic component on the mounting surface side.

2. The circuit board described in claim 1, wherein the lidded electronic component is disposed between a first line extending from one end of the contact-prevention component in the width direction parallel to the mounting surface toward the first electronic component, and a second line extending from the other end of the contact-prevention component in the width direction toward the first electronic component.

3. The circuit board according to claim 1, wherein a ground that is connected to the contact prevention part is mounted on the board body.

4. The circuit board according to claim 1, wherein a connector is mounted on the board body, and the connector is mounted on a back surface opposite the mounting surface on which the lidded electronic component is mounted.

5. The circuit board according to claim 1, wherein the contact prevention component is a dummy capacitor.

6. An electronic control device comprising: a circuit board; and a connector mounted on the circuit board, wherein the circuit board comprises: a board body; a first electronic component mounted on the mounting surface of the board body; a contact-prevention component mounted on the mounting surface of the board body and positioned at an end of the board body further than the first electronic component; and a lidded electronic component mounted on the mounting surface of the board body and positioned between the first electronic component and the contact-prevention component, wherein a protruding height from the mounting surface of the first electronic component and the contact-prevention component is set higher than a protruding height of the lidded electronic component, a first upper end of the lidded electronic component on the first electronic component side is contained within a space formed on the mounting surface by a line connecting an upper end of the first electronic component to a mounting end of the contact-prevention component on the mounting surface side, and a second upper end of the lidded electronic component on the contact-prevention component side is contained within a space formed on the mounting surface by a line connecting an upper end of the contact-prevention component to a mounting end of the first electronic component on the mounting surface side.

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