JP5691819B2 - Millimeter wave communication device casing structure and shield state detection method - Google Patents

Description

  The present invention relates to a millimeter wave device housing structure and a shield state detection method.

  In the case of millimeter wave communication device housings that are becoming increasingly complex, as described in Japanese Patent Application Laid-Open No. 2009-290600 “Antenna Elements and Wireless Communication Devices”, for example, as an internal structure for the purpose of preventing radio wave interference. The function blocks are divided. As shown in FIG. 8, the internal structure divided into functional blocks includes a case cover 1 having a shield wall 2 formed on a circuit board 6 via a cavity 25 and an SMD device 20 (Surface Mount Device: surface mount). Each circuit in which components are wired with solder 21 is covered, and is separated by a shield wall 2. The housing cover 1 is fixed to the chassis 5 with the bottom surface of the shield wall 2 in contact with the surface of the circuit board 6 by screwing the fixing screw 4 into the screw hole formed in the screw fixing portion 3. , Each functional block on the circuit board 6 is shielded. FIG. 8 is a cross-sectional view showing an example of the housing structure of the current millimeter wave communication apparatus.

  However, in the case structure of FIG. 8, generally, the part of the shield wall 2 formed on the case cover 1 is lengthened and deformed due to a reduction in the number of screw fixing points 3, and the like. It is difficult to maintain a good shield state. Further, not only the portion of the shield wall 2 but also the ground GND surface formed on the back surface side of the circuit board 6 is brought into close contact with the chassis surface grounding portion 8 formed on the inner surface of the chassis 5 (upper surface in FIG. 8). The shield property of the circuit board 6 is to be secured. However, the central area of the circuit board 6 on which the SMD device 20 is soldered and mounted is warped due to the stress difference between the front and back of the circuit board 6 and is located on the upper side. There is a possibility that a gap 13 is generated between the chassis 5 and the chassis 5.

  As a result, only the screw fixing portion 3 fixed by the fixing screw 4 comes into contact with the chassis surface grounding portion 8 of the chassis 5, and the central area of the circuit board 6 becomes insufficient to be in close contact with the chassis 5. Disturbance elements due to environmental changes induce a contact / non-contact state with the chassis surface grounding portion 8 of the chassis 5 and are a factor affecting RF (Radio Frequency) characteristics.

  Further, when the SMD device 20 mounted on the circuit board 6 generates particularly high heat, the gap 13 generated in the central region of the circuit board 6 reduces the thermal conductivity of the heat dissipation path, and the circuit board 6 is increasingly swollen (warped). As a result, the deterioration of heat dissipation is further accelerated. For this reason, the circuit board GND plane formed on the back surface side of the circuit board 6 does not function sufficiently as a ground GND surface, but also influences due to disturbances such as vibrations, flux (solder solvent) to the gap 13 part, etc. This may cause a problem due to the inflow of foreign matter and the like, and there is a possibility that RF characteristics as a millimeter wave communication device cannot be sufficiently ensured.

  9 is a cross-sectional view showing an example different from FIG. 8 of the circuit board mounting form of the current millimeter wave communication device, and the circuit board is formed as a two-layer structure of the main circuit board 22 and the sub circuit board 23. An example is shown. In FIG. 9, the SMD device 20 is fixedly mounted on the circuit pattern of the sub circuit board 23 with the solder 21, and each sub circuit board 23 is fixedly mounted on the circuit pattern of the main circuit board 22 with the solder 21. The main circuit board 22 is fixed to the chassis 5 by the fixing screws 4, and the ground planes (circuit board GND planes) formed on both front and back surfaces thereof are in close contact with the cover ground plane on the bottom surface of the shield wall and the chassis plane grounding portion 8 of the chassis 5. Like to do.

  However, in the case where the circuit boards are hierarchized as shown in FIG. 9, the central portion of the sub circuit board 23 is lifted due to the stress difference due to the physical properties of the board material of the main circuit board 22 and the sub circuit board 23. As a result, a solder connection defect area 24 is generated between the main circuit board 22 and the main circuit board 22. That is, a solder connection defect area 24 in which solder bonding is not performed occurs in the central portion of the sub circuit board 23. This factor is a result of not being able to withstand the stress with the main circuit board 22. As a result, as in the case of FIG. 8, a state in which the RF characteristics as the millimeter wave communication apparatus cannot be sufficiently secured occurs.

  When detecting abnormalities in the RF characteristics of millimeter-wave communication devices such as those described above, in a millimeter-wave communication device housing that forms a shield housing by maintaining a mechanically engaged state, stress such as vibration and temperature changes In many cases, an RF characteristic abnormality will not be detected unless an environmental test is applied.

  For this reason, in conventional millimeter-wave communication devices, temperature, humidity, vibration, and shock are externally applied from the evaluation device as environmental change states of disturbance elements so as not to miss unexpected abnormalities of RF characteristics. I was always trying to observe the change in RF characteristics.

JP 2009-290600 A (page 3-5)

  However, in the conventional measurement technique, not only the measurement action becomes complicated, but also the failure of the RF abnormality occurs, and even if the occurrence of the RF abnormality can be detected, it is linked to the prevention measures. Therefore, it is impossible to identify the problem occurrence site and confirm the state of the abnormal site.

  In addition, the shield state of the case cover of the millimeter wave communication device changes due to external influences such as environmental changes, and the circuit board is deformed when it is in contact with the shield wall of the case cover of the circuit board or in contact with the chassis. Even if an RF characteristic abnormality is induced by fluctuations in the distance between contact surfaces, alteration of the contact surfaces, or the occurrence of foreign matter biting between the contact surfaces, etc. It is possible to specify that the cause of the abnormality of the RF characteristics is due to the contact state with the shield wall or chassis surface of the housing cover, that is, the unstable shield state of the circuit board, and where the problem occurs. It is also technically difficult to confirm whether it exists.

  In a static state, it is impossible to observe or measure the contact state with the shield wall or chassis surface of the housing cover, that is, the shield state of the circuit board, by processing a part of the housing. Absent. However, even if it is observed in a state different from the operation of the original millimeter wave communication device, the effectiveness of the investigation / verification is low, and it is possible to accurately grasp whether the shield state is stable in the original operation state. The fundamental problem of being unable to do so cannot be solved.

(Object of the present invention)
The present invention has been made in view of such circumstances, and a millimeter-wave communication device casing structure and shield state that enable a defect of the casing shield structure that affects required RF characteristics to be reliably ascertained from the outside. Its purpose is to provide a detection method.

  In order to solve the above-described problem, the millimeter wave communication device casing structure and shield state detection method according to the present invention mainly adopts the following characteristic configuration.

  (1) The millimeter wave communication device casing structure according to the present invention includes a casing cover on which a shield wall is formed to divide and shield a circuit board having a ground plane portion formed on both front and back surfaces for each functional block. When the chassis cover is mounted on the chassis on which the circuit board is mounted or on the chassis on which the circuit board is mounted with a fixing screw, the bottom surface of the shield wall and the chassis cover. A millimeter-wave communication device mounting structure that realizes a shield state of the circuit board by contacting grounding parts respectively formed on the inner surface with the grounding surface parts formed on both front and back surfaces of the circuit board, wherein the shield A surface of the grounding surface portion formed on the circuit board and in a region on the circuit board in contact with the grounding portion formed on the bottom surface of the wall The change in the contact state between the grounding surface portion of the circuit board and the shield wall and the grounding portion formed in each of the chassis is detected and converted into a change amount of an electrical signal. And a detector for outputting the output.

  (2) A shield state detection method according to the present invention includes a housing cover on which a shield wall is formed to divide and shield a circuit board having grounding surface portions formed on both front and back surfaces for each functional block, When the case cover is fixed to the chassis on which the circuit board is mounted on the chassis on which the circuit board is mounted or the chassis on which the circuit board is mounted with a fixing screw, the bottom cover of the shield wall and the inner surface of the chassis, respectively A shield for detecting a shield state in the millimeter wave communication device mounting structure that realizes a shield state of the circuit board by contacting the formed ground part with the ground surface parts formed on the front and back surfaces of the circuit board. A state detection method in a region on the circuit board where the grounding portion formed on the bottom surface of the shield wall contacts. And the contact between the ground plane portion of the circuit board and the shield wall and the ground portion formed on each of the chassis at any location within the plane of the ground plane portion formed on the circuit board. A detection unit that detects a change in state, converts the change into an electrical signal change amount, and outputs the change is provided, and the circuit board uses the change amount of the electrical signal output from the detection unit. It is characterized by discriminating a change in the shield state.

  According to the millimeter wave communication device housing structure and shield state detection method of the present invention, the following effects can be obtained.

  The first effect is that the change in the shield state that affects the RF characteristics (high-frequency characteristics) due to environmental disturbances, etc., without affecting the actual operation RF characteristics even in the actual operation state, The change in the contact state between the grounding surface and the grounding part of the chassis cover or chassis is replaced with an electrical change that is easy to handle. Therefore, it is possible to grasp more accurately.

  The second effect is that the shield wall formed on the housing cover is in contact with the shield for each functional block, and is disposed at an arbitrary position in the plane of the ground plane on the circuit board. Sensing element that detects a change in the contact state between the ground surface portion of the circuit board and the housing cover or the grounding portion of the chassis as an electrical change amount (for example, a change in capacitance or a change in conductivity). By using this, it is possible to reduce the size, and with a simple circuit, it is possible to reliably extract abnormalities in the shield state that affect RF characteristics such as gap detection and contact / bonding defects. There is in being.

  The third effect is a combination of the first effect and the second effect, and even in the operation state of the millimeter wave communication apparatus, the shield state of the circuit board is divided into arbitrary local areas divided into functional blocks or comprehensively. It is possible to grasp it.

It is a perspective view for demonstrating an example of the millimeter wave communication apparatus housing | casing structure by this invention. It is the expansion perspective view which expanded the shield unstable region of the millimeter wave communication apparatus shown in FIG. It is sectional drawing which shows the cross-section of the shield unstable area of the millimeter wave communication apparatus of FIG. It is a block block diagram which shows an example of the shield state detection circuit which consists of an electrical connection block of the detection part arrange | positioned for every shield unstable area of the millimeter wave communication apparatus of FIG. It is an expansion perspective view which shows the other example which expanded the shield unstable area of the millimeter wave communication apparatus shown in FIG. It is sectional drawing which shows the cross-section of the shield unstable area of the millimeter wave communication apparatus of FIG. (A), (b) is sectional drawing for demonstrating a mode that the shield wall formed in the housing | casing cover of the millimeter wave communication apparatus of FIG. 5 moves with respect to a circuit board. (C), (d) is sectional drawing for demonstrating a mode that the shield wall formed in the housing | casing cover of the millimeter wave communication apparatus of FIG. 5 moves with respect to a circuit board. It is sectional drawing which shows an example of the housing | casing structure of the present millimeter wave communication apparatus. It is sectional drawing which shows the example different from FIG. 8 of the mounting form of the circuit board of the present millimeter wave communication apparatus.

  Preferred embodiments of a millimeter wave communication device housing structure and shield state detection method according to the present invention will be described below with reference to the accompanying drawings.

(Features of the present invention)
Prior to the description of the embodiments of the present invention, an outline of the features of the present invention will be described first. The present invention provides a housing structure for mounting a millimeter wave communication device having shield ground planes (GND planes) formed on both the front and back sides of a circuit board, in an actual operational state of the millimeter wave communication device. The change in the shield state of the circuit board that affects the RF characteristics of the millimeter wave communication device without affecting the radio frequency) characteristics, between the ground plane of the circuit board and the housing (housing cover or chassis) The main feature is to extract the change in the contact state, which indicates the change in the shield state, by converting it into an electrical change amount that is easier to handle, as well as grasping it as a change in the contact state with the grounding part. Yes.

(Configuration example of the millimeter wave communication device housing structure of the present invention)
Next, an embodiment of the housing structure of the millimeter wave communication device according to the present invention will be described in detail. FIG. 1 is a perspective view for explaining an example of a millimeter wave communication device casing structure according to the present invention, and also shows an example of an internal structure of a part of the casing.

  The millimeter wave communication device shown in FIG. 1 has a structure substantially similar to that of the conventional millimeter wave communication device shown in FIG. 8, and a circuit board 6 mounted on a chassis 5 is covered with a casing cover having a shield wall 2. The shield structure is fixed by a fixing screw 4 in a state of being covered with 1, and is divided into functional blocks by a shield wall 2 that is in contact with the surface of the circuit board 6. In FIG. 1, the circuit board GND plane 7 which is the ground plane of the circuit board 6 and the cover of the bottom surface of the shield wall 2 are located in the middle of the positions where the screw fixing places 4 for inserting the fixing screws 4 are arranged. A shield unstable region 10 where the contact with the ground contact surface 15 or the chassis surface grounding portion 8 on the inner surface of the chassis 5 becomes unstable is shown by partially cutting the housing cover 1 and the shield wall 2.

  FIG. 2 is an enlarged perspective view in which the shield unstable region 10 of the millimeter wave communication device shown in FIG. 1 is enlarged. In order to grasp the shield state of the circuit board 6 in the operation state of the millimeter wave communication device, The example which has arrange | positioned the detection part 9 peculiar to this invention in the said shield unstable area 10 is shown.

  That is, as shown in FIG. 2, the circuit board GND plane 7 formed as a shield on both the front and back sides of the circuit board 6, the cover ground surface 15 on the bottom surface of the shield wall 2, and the chassis surface grounding portion 8 on the inner surface of the chassis 5. The circuit board is configured so that the detection unit 9 capable of detecting the contact state does not affect the RF characteristics required for the millimeter wave communication device even when the millimeter wave communication device is in an actual operation state. 6 is disposed. That is, it is in the shield unstable region 10 where the contact with the shield wall 2 or the chassis 5 formed on the housing cover 1 is assumed to be unstable, and the bottom surface of the shield wall 2 In any region within the area on the circuit board 6 that is in contact and within the surface of the circuit board GND plane 7 formed on the surface of the circuit board 6, the detection wall 9 and the shield wall 2 and the chassis 5 are provided. By providing a sensing pad that can detect the contact state of the shield as an electrical signal, a change in the contact state with the shield wall 2 or the chassis 5 is electrically changed (for example, capacitance or Change amount of conduction).

  3 is a cross-sectional view showing a cross-sectional structure of the shield unstable region 10 of the millimeter wave communication device of FIG. 2, and a cross section perpendicular to the surface of the circuit board 6 through the line III-III of FIG. The cross-sectional structure when viewed is shown. As shown in the cross-sectional view of FIG. 3, the circuit board GND plane 7 on the back surface side (the lower surface in FIG. 3) of the circuit board 6 in the shield unstable region 10 is the chassis surface contact formed on the inner surface of the chassis 5. On the other hand, a detection unit 9 for grasping the shield state of the circuit board GND plane 7 or the circuit board 6 is disposed on the surface side of the circuit board 6 (upper surface in FIG. 3). In addition, a cover grounding surface 15 formed on the shield wall 2 of the housing cover 1 is disposed at a position facing the circuit board GND plane 7 and the detection unit 9 and is fixed with a fixing screw. , Are in close contact with each other.

  In addition, the detection part 9 is each arrange | positioned for every shield unstable area 10 which may arise in the area | region divided for every function of a millimeter wave communication apparatus, and as shown in FIG. In order to make it possible to grasp in more detail the contact state between the ground plane of the substrate 6 (circuit board GND plane) and the bottom surface of the shield wall 2 and the ground portion of the chassis 5, the local sensing pad a11 and the local sensing pad b12 is paired. In addition, a via hole 14 (via hole: plated hole) for electrically connecting the layers is appropriately formed in the circuit board 6 so that each surface in the layer is electrically connected. The inner layer wiring 16 is disposed. The change in the shield state detected by being converted into an electrical signal by the detection unit 9 is output to the circuit unit that determines the shield state of the circuit board 6 through the inner layer wiring 16.

  Next, an example of an electrical connection path of the detection unit 9 will be described with reference to FIG. FIG. 4 is a block configuration diagram illustrating an example of a shield state detection circuit including an electrical connection block of the detection unit 9 arranged for each shield unstable region 10 of the millimeter wave communication apparatus of FIG. As described above, the detection unit 9 includes the first detection unit 91, the second detection unit 92, the second detection unit 92, and the second detection unit 92 for each of the plurality of shield instability regions 10 positioned in the middle of the screw fixing portion 4 where the fixing screw 4 is inserted. Are arranged as the n-th detection unit 9n, and the electrical change amount in each of the first detection unit 91, the second detection unit 92, the third detection unit 93, ..., the n-th detection unit 9n. The detection results detected as (for example, the amount of change in capacitance or conductivity) are output to the signal amplification / conversion circuit 17, respectively.

  The signal amplification / conversion circuit 17 includes a first amplification / conversion circuit 171, a second amplification / conversion circuit 172, a third amplification / conversion circuit 173,. 17 n is provided and is connected to each of the corresponding detection units 9 by an inner layer wiring in the circuit board 6. Therefore, the detection results output from the first detection unit 91, the second detection unit 92, the third detection unit 93,..., The nth detection unit 9n are the first amplification / conversion circuit 171 and the second amplification / conversion. The circuit 172, the third amplifier / converter circuit 173,..., The nth amplifier / converter circuit 17n are amplified and converted into digital signals.

  The conversion signals relating to the detection results output from the signal amplification / conversion circuits 17 are appropriately collected in the AND / OR selection circuit 18 according to the detection target range. Thereafter, the determination / operation control / state recording circuit 19 determines the shield state of the circuit board 6 and outputs a control signal for controlling the operation state of the millimeter-wave communication device, if necessary. The shield state of the determined circuit board 6 is recorded and saved, and when an abnormal situation is detected, a notification to that effect is sent to the maintenance person.

  Thus, in order to detect the shield state of the circuit board 6 at an arbitrary position within the shield instability region 10 in the middle position of the fixing screw 4 that fixes the housing cover 1 as a shield part that causes abnormal RF characteristics. By disposing the local sensing pad a11 and the local sensing pad b12 as the detection unit 9, the circuit board GND plane 7 of the circuit board 6 is classified according to the location of the circuit board 6, that is, for each functional block of the circuit board 6. The contact / bonding state including the contact state or the non-contact state between the formation surface and the bottom surface of the shield wall 2 or the grounding portion of the chassis 5 can be accurately grasped. Note that the detection result of the detection unit 9 can be configured to detect a local shield state for each location by appropriately switching and selecting in the AND / OR selection circuit 18 shown in FIG. It is also possible to connect the detection results of a plurality of detection units 9 so as to collectively detect a shield state and connect all the detection results of the detection units 9 together. It is also possible to configure so as to detect the entire shield state of the circuit board 6.

  The detection result of each detection unit of the detection unit 9 is input to each circuit unit of the signal amplification / conversion circuit 17 corresponding to the detection result by wiring in the circuit board 6, and finally, determination / operation control is performed. In the state recording circuit 19, since the state of the housing shield part is regarded as a change in the amount of electricity different from the RF characteristics of the millimeter wave communication device, the shield state detection circuit like this The effect that the shield state can be detected without affecting the original RF characteristics can be obtained.

  In addition, as a local sensing pad which comprises the detection part 9 shown in FIG. 3, when the shield wall 2 which is a to-be-detected body, the housing | casing cover 1, etc. are comprised with a nonelectroconductive substance, It is essential to have a bipolar sensing pad configuration comprising at least the local sensing pad a11 and the local sensing pad b12. However, the shield wall 2 and the housing cover 1 which are the objects to be detected on the opposite surface are used as conductive substances. In this case, the configuration is not limited to the bipolar sensing pad configuration. In some cases, the single sensing pad is composed of only one of the local sensing pad a11 and the local sensing pad b12. It may be a configuration.

  In addition, by expressing the detection result of each detection unit of the detection unit 9 as a numerical value indicating the amount of change in capacitance, a distance (interval) or gap between the circuit board 6 and the bottom surface of the shield wall 2 or the chassis 5 is obtained. It is also possible to perform numerical conversion as a value indicating the physical properties of the foreign matter intervening. Further, when the operation is limited to the detection operation for the presence / absence of contact between the ground plane of the circuit board 6 (circuit board GND plane 7) and the bottom surface of the shield wall 2 or the chassis 5, a numerical value indicating the amount of change in capacitance is used. Instead, it can also be expressed as a numerical value of only two values of “0” and “1” indicating the presence or absence of direct current conduction, and the circuit configuration of the shield state detection circuit for detecting the shield state is simple. It becomes possible.

  In addition, as described above, the result obtained by the shield state detection circuit as described above can also grasp whether or not an abnormal situation has occurred for each functional block of the circuit board 6, and shields the maintenance personnel. This can be effectively used when adding a function that activates a defective alarm or a function that restricts the operation of the millimeter wave communication device.

  It should be noted that the shield wall 2 constituting the housing cover 1 and the formation surface of the circuit board GND plane 7 are almost always made of different materials, and crevice corrosion is likely to occur at the contact portion between the two. Yes. Therefore, by observing the gap between the contact parts of the shield state detection circuit, the occurrence of the gap is detected and notified to the maintenance personnel to prevent the occurrence of crevice corrosion in advance and improve the shield quality. It is also possible to maintain it effectively.

  In addition, each circuit except the detection unit 9 of the shield state detection circuit need not always be installed and operated in the circuit board, and is configured to be connected only when necessary to measure the shield state. When it becomes necessary, the primary operation may be performed by an external connection. By adopting such an external configuration, it becomes possible to reduce the circuit scale of the millimeter wave communication apparatus.

  As described above, by adopting the case structure of the millimeter wave communication apparatus according to the present invention as illustrated in FIG. 2, unlike the conventional technique shown in FIGS. 8 and 9, the millimeter wave communication apparatus. It is possible to detect a change in the shield state of the circuit board 6 that causes abnormal RF characteristics in the original operating state as well as the ground plane (circuit board GND plane 7) of the circuit board 6 and the shield. It is possible to reliably detect the occurrence of a gap between the bottom surface of the wall 2 and the grounding portion (the cover grounding surface 15 or the chassis surface grounding portion 8) on the inner surface of the chassis 5, or to reliably extract the occurrence portion of contact / bonding defects. can do.

  In the present embodiment, an example is shown in which the circuit board 6 whose shield state is to be grasped is formed as a single multilayer board in which ground surfaces are formed on both the front and back surfaces. However, as shown in FIG. 9 as the prior art, it is of course possible to configure the circuit board by a hierarchical configuration of the main circuit board and the sub circuit board. That is, by using a circuit element that detects a change in capacitance as the detection unit 9 shown in FIG. 2, only detection of contact / bonding status on the bonding surface with the sub circuit board mounted on the main circuit board is possible. In addition, the same configuration can be applied to the detection of the contact / bonding state at the part of the surface to which the insulating material is bonded. Furthermore, as an electrical circuit function, a circuit configuration such as the shield state detection circuit shown in FIG. 4 is used, and an electrical detection result of change in capacitance is determined by the determination / operation control / state storage circuit 19. By doing so, it is also possible to control the operation of the millimeter wave communication apparatus to be stopped when the contact / bonding situation is abnormal.

(Operation example of millimeter wave communication apparatus of the present invention)
Next, the operation example of the millimeter wave communication apparatus of the present invention shown as an example in FIGS. 1 to 4 will be described in more detail.

  In the millimeter wave communication apparatus according to the present embodiment, as shown in the cross-sectional view of FIG. 3, the circuit cover that affects the required RF characteristics (required high frequency characteristics) has a housing cover 1 and a chassis for each functional block. In order to detect the shield state of the circuit board 6 in any form within the surface of the circuit board GND plane 7 of the circuit board 6 serving as a contact portion with the circuit board 5 without affecting the grounding effect in the original operation. The local sensing pad a11 and the local sensing pad b12 are arranged as the detection unit 9.

  That is, a region on the circuit board 6 where the bottom surface of the shield wall 2 is in contact with the shield unstable area 10 where the gap 13 may be generated between the circuit board 6 and the required RF characteristics may be affected. The local sensing pad a11 and the local sensing pad b12 are arranged as a detection unit 9 at an arbitrary position within the same plane as the formation surface of the circuit board GND plane 7 on the circuit board 6. ing.

  Thus, in the shield state detection circuit including the detection unit 9 including the local sensing pad a11 and the local sensing pad b12, the presence or absence of a gap between the circuit board 6 and the shield wall 2 or the chassis 5 is detected. If there is a change in the shield state of the circuit board 6 including the detection of the change in the gap amount (interval), and the detection of the change in the state due to the entry of foreign matter into the generated gap, the occurrence of corrosion alteration, etc. As a result of detection, as shown in FIG. 4, it is possible to detect by replacing with an electrical change amount that is easier to handle, such as a change in capacitance and a change in conductivity / insulation amount.

  It should be noted that the occurrence period of contact failure occurring in the housing cover 1 and the chassis 5 due to external factors is generally extremely longer than the period in the frequency band (RF band) of signals transmitted and received by the millimeter wave communication device. Since the frequency is extremely low (ie, the frequency is extremely low), it can be considered that sufficient performance is obtained as a function of detecting the shield state of the circuit board 6 by the shield state detection circuit of FIG. Therefore, even in the actual operation state of the millimeter wave communication apparatus, the shield state of the circuit board 6, that is, the shield wall 2 of the housing cover 1 and the chassis 5 is not affected without affecting the signal characteristics during the actual operation. Can be observed in each functional block of the circuit board 6 or in a state where a plurality of locations are collected, and the behavior of the millimeter wave communication device at each location where the shield abnormality occurs. In addition, it is possible to grasp the influence on disturbance resistance and RF characteristics, and the relationship thereof more accurately.

  As for the detection unit 9 that locally captures the shield status, as a local detection unit, it is detected whether or not a state where the grounding surface of the circuit board 6 is not in contact with the grounding unit of the shield wall 2 or the chassis 5 has occurred. If this is sufficient, the number of wiring to the circuit board 6 for detecting the shield state can be constituted by only one wiring, and the number of inner layer wirings is greatly changed from the conventional specification as shown in FIG. There is no need to do this, and it is also possible to ensure the shielding performance against the original circuit board 6 in a simpler and more compact state.

  In addition, as described with reference to FIG. 4, by arranging a plurality of detection units 9 including local sensing pads a11 and local sensing pads b12 at arbitrary locations, it is possible to capture the behavior at each location, Overall, it is also possible to make a determination by collecting the detection results of all the detection units 9 together. Further, the result of capturing the change in the shield state of the circuit board 6 as an electrical change amount is not only utilized during evaluation / verification, but also a fail-safe function or the like, or the fixing screw 4 of the housing cover 1. It can also be applied to shield abnormality detection due to fixing abnormality, etc., and it is possible to quickly detect the crevice corrosion phenomenon, which is the initial stage of falling into a shield defect state.

(Explanation of effect of embodiment)
As described in detail above, the following effects are obtained in the present embodiment.

  The first effect is that, even in an actual operation state, a change in the shield state that affects the RF characteristics (high frequency characteristics) due to environmental disturbances without affecting the RF characteristics in actual operation, 6 and the ground cover of the housing cover 1 and chassis 5 (cover ground surface 15 and chassis grounding portion 8) as a change in the contact state, and the housing cover 1 and chassis. By replacing the change in the contact state with the grounding part 5 with an electrical change amount that is easy to handle, it is possible to grasp more accurately.

  The second effect is in a region where the bottom surface of the shield wall 2 formed on the housing cover 1 is in contact with each other to shield each functional block, and the ground surface portion on the circuit board 6 (circuit board GND plane). 7) The detection unit 9 (local sensing pad a11, local sensing pad b12) arranged at an arbitrary position in the plane of 7) is connected to the grounding surface part (circuit board GND plane 7) of the circuit board 6 and the housing cover 1 or A detection element that detects a change in a contact state with the grounding portion (the cover grounding surface 15 or the chassis surface grounding portion 8) of the chassis 5 as an electrical change amount (for example, a change amount in capacitance or a change in conductivity amount) is used. It is possible to reduce the size and make it possible to reliably extract abnormalities in the shield state that affect the RF characteristics such as gap detection and contact / bonding defects with a simple circuit. It lies in the fact you are.

  According to the third effect, the shield state of the circuit board 6 can be set for each arbitrary local area divided into functional blocks, even in the operation state of the millimeter wave communication device, by the synergistic effect of the first effect and the second effect. It is to be able to grasp comprehensively.

  In general, the capacitance measurement can be easily realized by a commercially available IC. However, in the present invention, when it is limited only to the detection of the quality of the contact state of the shield surface, '0', A simpler circuit can also be configured by using as an index the presence or absence of conductivity for a direct current component that indicates only the binary value of “1”.

(Other embodiments of the present invention)
Next, as another embodiment of the present invention, an example of a millimeter wave communication device housing structure different from those in FIGS. 1 and 2 will be described. FIG. 5 is an enlarged perspective view showing another example in which the shield unstable region 10 of the millimeter wave communication device shown in FIG. 1 is enlarged, and grasps the shield state of the circuit board 6 in the operation state of the millimeter wave communication device. Therefore, an arrangement example different from that of FIG. 2 of the detection unit 9 arranged in the shield unstable region 10 is shown. 6 is a cross-sectional view showing a cross-sectional structure of the shield unstable region 10 of the millimeter wave communication device of FIG. 5, and a cross section perpendicular to the surface of the circuit board 6 through the line IV-IV of FIG. A cross-sectional structure when viewed from the direction is shown.

  In this embodiment, as shown in the cross-sectional view of FIG. 6, the circuit board 6 has a base plate 29 mounted on the chassis 5 for heat diffusion and assembly, unlike the case of FIG. The circuit board 6 is assembled to the base plate 29 with a board fixing screw 30. The front surface side (the upper surface side in FIG. 6) of the circuit board 6 is covered with the housing cover 1 having the shield wall 2 via the cavity 25. Here, although not shown on the surface side of the circuit board 6 (upper surface in FIG. 3), as in the case of FIG. 3, the circuit board GND plane 7 or the shield state of the circuit board 6 is grasped. In the state where the detection unit 9 is arranged and the cover grounding surface 15 formed on the shield wall 2 of the housing cover 1 is arranged at the opposite position and is fixed by screwing with a fixing screw, The substrate GND plane 7 and the cover ground plane 15 are in close contact with each other. As a result, the circuit board GND plane 7 of the circuit board 6 and the cover ground surface 15 of the shield wall 2 are in contact with each other, and the circuit board GND plane 7 on the surface side of the circuit board 6 (upper surface side in FIG. 6) is grounded. I have to.

  On the other hand, with respect to the back surface side of the circuit board 6 (lower surface side in FIG. 6), the base plate contact surface 31 and the base plate 29 formed on the back surface side (lower surface side in FIG. 6) of the circuit board 6 are in close contact. Further, the base plate 29 is brought into close contact with the chassis surface grounding portion 8 formed on the chassis 5 so that the base plate contact surface 31 on the back surface side (the lower surface side in FIG. 6) of the circuit board 6 is formed. It is structured to be grounded.

  Here, as shown in FIG. 6, when the soldering component 26 is attached to the base plate 29 by the solder 21, the flux 28 of the solder 21 is caused by the capillary (capillary) effect when the solder 21 is melted. May penetrate into the slight gap 13 between the back side of the circuit board 6 and the base plate 29, and an unintended flux filling region may be formed in the gap 13.

  As a result, the casing cover 1 is pressed against the chassis 5 side by the fixing screw 4 to form a shield structure, but the circuit board generated by the thermal stress when the SMD device as described in FIG. 8 is soldered. In addition to the gap 13 between the circuit board 6 and the base plate 29, the gap 13 between the circuit board 6 and the shield wall 2, and the like, the ground surface of the circuit board 6 includes the gap 13 that forms the flux filling area. It cannot function perfectly as (base plate ground plane 31, circuit board GND plane 7), and not only fixed defects but also many places where the shield is unstable may occur.

  Therefore, as shown in FIG. 5, by arranging the detection unit 9 for detecting the shield state at an arbitrary place in the incomplete shield area 10, the circuit like this is the same as in FIGS. In addition to detecting the presence or absence of fixed defects on the grounding surface of the substrate 6, the circuit board 6 is connected based on the result of substituting the electrical monitoring for the fluctuation / behavior of the temporal shield state. It is also possible to detect the stability and instability indicating whether the ground is stable and completely grounded. By determining the shield state of the millimeter wave communication device based on the amount of electrical change, even if the physical grounding is incomplete, the electrical circuit operation of the millimeter wave communication device As long as the determination result that the grounding state is stable is obtained, it can be considered that practical stability is obtained as the RF characteristic of the signal transmitted and received by the millimeter wave communication device. The effect that it is possible is also obtained.

  Further, as shown in FIG. 2 and FIG. 5, the detection unit 9 is provided with a cover grounding surface 15 while enabling the arrangement state of the via hole for grounding to be exactly the same as the arrangement state in other regions. Since the shield wall 2 is formed so as to be within the region where the shield wall 2 is disposed, the RF characteristics of the millimeter wave communication device are affected without weakening the shield state (ground state) of the circuit board 6. There is no.

  If the local sensing pad a11 and the local sensing pad b12 constituting the detection unit 9 are formed in a region protruding from the shield wall 2, the detection unit 9 is originally a ground plane portion, In the millimeter wave communication device, the circuit patterns of the local sensing pad a11 and the local sensing pad b12 of the detection unit 9 become stubs and antennas, which may unintentionally affect the RF characteristics in the original operation. It will be high. In the detection unit 9 shown in FIG. 2 and FIG. 5, since it is formed without breaking the structure of the ground plane, the occurrence of such adverse effects can be completely prevented.

  In the above description, the gap 13 in which the shield state becomes unstable is a direction perpendicular to the front surface and the back surface of the circuit board 6 (vertical direction in FIGS. 8 and 9; here referred to as the z-axis direction). The case has been described that occurs when the circuit board 6 floats. However, the present invention is not limited to the generation of the gap 13 due to the floating of the circuit board 6 in the z-axis direction, and the gap 13 generated by movement in any direction is shown in FIG. 2 and FIG. It is possible to detect by arranging such a detection unit 9, and it is possible to detect instability of the shield state that occurs based on the presence of the gap 13.

  For example, as shown in FIG. 7A (b), the shield wall 2 disposed on the front surface side (upper surface side in the figure) of the circuit board 6 moves up and down in the z-axis direction with respect to the circuit board 6. However, as shown in FIG. 7B (c), even when the shield wall 2 moves laterally with respect to the circuit board 6 in the x-axis direction or the y-axis direction, or as shown in FIG. 7B (d). As described above, even when the shield wall 2 is tilted with respect to the circuit board 6 and tilted in the combined direction of the x, y, and z axes, the instability of the shield state can be detected by the detection unit 9. It is.

  7A (a), (b) and FIGS. 7B (c), (d) show that the shield wall 2 formed on the housing cover 1 of the millimeter wave communication device of FIG. It is sectional drawing for demonstrating a mode that it moves, and has shown sectional structure at the time of seeing the cross section perpendicular | vertical to the surface of the circuit board 6 through line IV-IV of FIG. 7A shows a case where the shield wall 2 of the millimeter wave communication apparatus of FIG. 5 is in a normal state where it does not move with respect to the circuit board 6, and the local area constituting the detection unit 9 is shown. Both the sensing pad a11 and the local sensing pad b12 are within the region of the shield wall 2. FIG. 7A (b) shows a case where the shield wall 2 of the millimeter wave communication apparatus of FIG. 5 moves in the z-axis direction with respect to the circuit board 6, and there is a gap between the shield wall 2 and FIG. Can be detected by both the local sensing pad a11 and the local sensing pad b12.

  7B (c) shows a case where the shield wall 2 of the millimeter wave communication device of FIG. 5 moves in the x-axis direction or the y-axis direction or both the x and y axes with respect to the circuit board 6 as described above. Among the local sensing pad a11 and the local sensing pad b12 constituting the detection unit 9, the local sensing pad b12 protrudes from the region of the shield wall 2, but the local sensing pad a11 is a shield. It is within the region of the wall 2 and it is possible to detect that the positional relationship with the shield wall 2 has shifted. In order to make it possible to detect the movement even if it is shifted in either direction of the x-axis or the y-axis, as shown in FIG. 5, the local sensing pad a11 and the local sensing pad The positional relationship with b12 is not arranged in parallel with each other as in the case of FIG. 2, but is arranged in a diagonal direction.

  FIG. 7B (d) shows a case where the shield wall 2 of the millimeter wave communication apparatus of FIG. 5 is inclined with respect to the circuit board 6 as described above, and the local sensing pad constituting the detection unit 9 is shown. Of the a11 and the local sensing pad b12, the local sensing pad a11 detects that the gap with the shield wall 2 is enlarged, and the local sensing pad b12 detects that the gap with the shield wall 2 is narrowed. In addition, it is possible to detect that the positional relationship with the shield wall 2 is tilted.

  In other words, by converting the detection results of the local sensing pad a11 and the local sensing pad b12 arranged as the detection unit 9 at an arbitrary place in each shield unstable region 10 of the circuit board into electrical change amounts and appropriately combining them. , The floating amount (z) of the shield wall 2 in the z-axis direction, the lateral shift (x, y) in the xy-axis direction, the inclination degree (θ), and the respective temporal fluctuation amounts (change / behavior) are detected. Therefore, it is possible to realize a more accurate state grasping function as compared with the prior art.

  The electrical signal indicating the detection result of the detection unit 9 described above is a DC (direct current) signal in the explanation of the operation. However, when a DC signal is used, contact between different metals is performed at the joint portion that becomes the GND ground plane. It cannot be denied that galvanic cells are formed or metal migration by DC application (always energization) is promoted. Therefore, in actual operation, it is desirable to use an (AC + DC) signal that also uses an AC (alternating current) component.

  The configuration of the preferred embodiment of the present invention has been described above. However, it should be noted that such embodiments are merely examples of the present invention and do not limit the present invention in any way. Those skilled in the art will readily understand that various modifications and changes can be made according to a specific application without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Case cover 2 Shield wall 3 Screw fixing location 4 Fixing screw 5 Chassis 6 Circuit board 7 Circuit board GND plane 8 Chassis surface grounding part 9 Detection part 10 Shield unstable area 11 Local sensing pad a
12 Local Sensing Pad b
13 Clearance (floating)
14 Via Hole
15 Cover ground plane 16 Inner layer wiring 17 Signal amplification / conversion circuit 18 AND / OR / selection circuit 19 Judgment / operation control / state recording circuit 20 SMD device 21 Solder 22 Main circuit board 23 Sub circuit board 24 Solder connection defect area 25 Cavity 26 Soldering component 28 Flux 29 Base plate 30 Substrate fixing screw 31 Base plate contact surface 91 First detection unit 92 Second detection unit 93 Third detection unit 9n N detection unit 171 First amplification / conversion circuit 172 Second amplification Conversion circuit 173 Third amplification / conversion circuit 17n nth amplification / conversion circuit

Claims (10)

  A circuit board having grounding surface portions formed on both front and back surfaces is provided with a housing cover on which a shield wall is formed for separating and shielding each functional block, and the housing cover is mounted on the chassis on which the circuit board is mounted. Alternatively, when the circuit board mounted on the base plate is fixed to the chassis on which the circuit board is mounted with fixing screws, the grounding portions respectively formed on the bottom surface of the shield wall and the inner surface of the chassis are the front and back surfaces of the circuit board. A millimeter-wave communication device mounting structure that realizes a shield state of the circuit board by contacting the grounding surface portions formed on both surfaces, wherein the circuit contacts the grounding portion formed on the bottom surface of the shield wall The grounding of the circuit board at any location within a region on the board and in the plane of the grounding surface portion formed on the circuit board. A detector that detects a change in contact state between the contact portion and the grounding portion formed on each of the shield wall and the chassis, converts the change into an electrical signal change amount, and outputs the change. A featured millimeter-wave communication device mounting structure.   The detection unit is disposed on the circuit board in a shield unstable region in which a contact state between the grounding surface part of the circuit board, the shield wall, and the grounding part of the chassis may become unstable. The millimeter-wave communication device mounting structure according to claim 1, wherein the millimeter-wave communication device mounting structure is provided.   The detection unit is a pair of local sensing pads that detect a change in a contact state between the grounding surface portion of the circuit board and the shield wall and the grounding portion of each chassis as a change amount of an electrical signal. 2. The bipolar structure according to claim 1, or a single-pole structure having only one local sensing pad, which is disposed at one or a plurality of locations on the circuit board. 2. The millimeter wave communication device mounting structure according to 2.   As a change amount of an electrical signal converted and output by the detection unit, a change in a contact state between the grounding surface portion of the circuit board, the shield wall, and the grounding portion of each of the chassis is represented by a capacitance of capacitance. The millimeter wave communication device mounting structure according to any one of claims 1 to 3, wherein the millimeter wave communication device mounting structure converts the value into either a change in value or a change in electrical conductivity and outputs the result.   In the case where a plurality of detection units are provided on the circuit board, a local shield at the location where each detection unit is provided based on the amount of change in the electrical signal output from each detection unit. Whether to determine the state, or to determine the shield state that collects the locations of the plurality of detection units selected as appropriate, or to determine the overall shield state that integrates all of the plurality of detection units 5. The millimeter wave communication device mounting structure according to claim 1, further comprising selection means for switching and selecting any of the above.   A circuit board having grounding surface portions formed on both front and back surfaces is provided with a housing cover on which a shield wall is formed for separating and shielding each functional block, and the housing cover is mounted on the chassis on which the circuit board is mounted. Alternatively, when the circuit board mounted on the base plate is fixed to the chassis on which the circuit board is mounted with fixing screws, the grounding portions respectively formed on the bottom surface of the shield wall and the inner surface of the chassis are the front and back surfaces of the circuit board. A shield state detection method for detecting a shield state in a millimeter wave communication device mounting structure that realizes a shield state of the circuit board by contacting the ground plane portions formed on both sides, the bottom surface of the shield wall In the region on the circuit board with which the grounding portion formed is in contact, and formed on the circuit board By detecting a change in the contact state between the grounding surface portion of the circuit board, the shield wall, and the grounding portion formed in each of the chassis at an arbitrary location within the surface of the ground portion, A detection unit that converts into a change amount and outputs the change amount is provided, and a change in the shield state of the circuit board is determined using a change amount of an electrical signal output from the detection unit. Shield state detection method.   The detection unit is disposed on the circuit board in a shield unstable region in which a contact state between the grounding surface part of the circuit board, the shield wall, and the grounding part of the chassis may become unstable. The shield state detection method according to claim 6, wherein the shield state is detected.   The detection unit is a pair of local sensing pads that detect a change in a contact state between the grounding surface portion of the circuit board and the shield wall and the grounding portion of each chassis as a change amount of an electrical signal. 7. A bipolar configuration as described above, or a single-polar configuration with only one local sensing pad, respectively, disposed at one or more locations on the circuit board. 8. The shield state detection method according to 7.   As a change amount of an electrical signal converted and output by the detection unit, a change in a contact state between the grounding surface portion of the circuit board, the shield wall, and the grounding portion of each of the chassis is represented by a capacitance of capacitance. 9. The shield state detection method according to claim 6, wherein the shield state detection method converts the value into a change in value or a change in electrical conductivity and outputs the result.   In the case where a plurality of detection units are provided on the circuit board, a local shield at the location where each detection unit is provided based on the amount of change in the electrical signal output from each detection unit. Whether to determine the state, or to determine the shield state that collects the locations of the plurality of detection units selected as appropriate, or to determine the overall shield state that integrates all of the plurality of detection units The shield state detecting method according to claim 6, further comprising a selection step of switching and selecting any of the above.

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