JP4535939B2 - Hole reinforcing member and substrate support structure - Google Patents

Description

  The present invention fixes a hole reinforcing member provided in a through hole of a circuit board fixed to a supporting member with a screw, and a circuit board electrically connected to another circuit board via a connector portion to the supporting member with a screw. And a substrate support structure for grounding.

  2. Description of the Related Art Conventionally, in an electronic device such as a household appliance, a connector portion having a very large number of connection pins is used for a circuit board as electronic components mounted on the circuit board are highly integrated. In such a connector portion, as the number of connection pins increases, the load acting on the connection pins when the connector portions are fitted to each other tends to increase relatively.

  On the other hand, in order to reduce the size of electronic devices and circuit boards, the connector portion has a narrow pitch between the connection pins and a relatively thin connection pin. For this reason, there is an increasing number of cases where sufficient mechanical strength cannot be obtained for the connection pins only by fixing by soldering due to the influence of variations in the dimensions of the components.

  Further, due to the nature of the connector portion, the connection state may be removed depending on the handling status of the electronic device, and structural fixing such as tightening the vicinity of the connector portion with a fixing screw is often required. For this reason, torque due to screw tightening is often applied to the connector portion.

  In recent years, circuit boards are mounted with many electronic components that generate high frequencies as the operating speed increases, and are provided on circuit boards to ensure good characteristics such as EMI (Electro Magnetic Interference). It is necessary to securely connect the grounding part having the grounding pattern to the grounding part of the electronic device. For this reason, a configuration is generally employed in which the ground portion of the circuit board also serves as a fixing portion for fixing the circuit board to a support frame that supports the circuit board.

  As shown in FIG. 10, a conventional substrate support structure employed in a projection display device is connected to a first circuit board 111 provided with a connector part, and the first circuit board 111 via the connector part. A second circuit board 112 and a third circuit board 113, a support frame 115 for supporting each of the circuit boards 111, 112, 113, and a fixing screw 116 for fixing the first circuit board 111 to the support frame 115. I have.

  Although not shown, the first circuit board 111 is provided with a through hole through which the fixing screw 116 is inserted, and a grounding surface that is grounded via the support frame 115 is provided on the outer periphery of the through hole. Yes. Further, a hole reinforcing member 117 which is a so-called eyelet (eyelet) for reinforcing the through hole is fixedly provided in the through hole of the first circuit board 111. The support frame 115 is provided with a support portion (not shown) that supports the vicinity of the through hole of the first circuit board 111. The support frame 115 is electrically connected to a ground portion (not shown) of the projection display device.

As described above, as another conventional configuration in which the eyelet provided in the through hole of the circuit board is used for grounding the circuit board, the protrusion provided on the eyelet is applied on the metal surface of the circuit board. The structure which implement | achieves conduction | electrical_connection by penetrating the insulating material which reached the metal base is disclosed (for example, refer patent document 1). Another conventional configuration using eyelets is a configuration that improves the reliability of the state of electrical connection between the eyelet and the circuit board by screwing the eyelet having a threaded portion on the outer periphery into the through hole of the circuit board. Is disclosed (for example, see Patent Document 2).
JP 59-876 JP-A-8-37356

  By the way, the conventional substrate support structure provided in the above-described projection display device has the following problems.

  As a first problem, each connector portion provided on each circuit board has a plurality of connection pins arranged at a pitch of, for example, about 0.5 mm and soldered and joined. In such a connector portion, it is difficult to increase the mechanical strength of the soldering portion of the connection pin, and it is necessary to consider that stress is not applied to the soldering portion as much as possible. However, as shown in FIG. 10, when the first circuit board 111 is screwed to the support portion of the support frame 115 with the fixing screw 116, the screw tightening torque is applied to the first circuit board 111 in the direction of arrow F in FIG. Works. When the rotational force acts on the first circuit board by the screw tightening torque, a tensile stress in a specific direction is applied to each connector portion of the second circuit board 112 and the third circuit board 113. For this reason, a crack etc. arise in the soldering part of each connector part, and there exists a possibility that the reliability of the electrical connection state by a connector part may be impaired.

  This problem is particularly caused when the dimensions of the connection pads provided for joining the connection pins cannot be ensured to be relatively large on the circuit board, and the number of connection pins is relatively large and relatively small. This is remarkable in the case of the connector part.

  The second problem is that, as a measure to reduce the screw tightening torque, the eyelet is made of a resin material having a relatively high slidability so that the eyelet slides and rotates with respect to the through hole. It is also possible to do. However, in an electronic device, in order to ensure good EMI characteristics, it is necessary to electrically connect the ground plane of the circuit board and the ground portion of the electronic device. Since it is difficult to connect to the glass, there is an inconvenience that the eyelet cannot be formed with the resin material.

  Therefore, the present invention can prevent the circuit board from rotating with respect to the support member due to the screw tightening torque generated when the circuit board is fixed to the support member with a screw, and can ensure a good grounding state of the circuit board. An object is to provide a hole reinforcing member and a substrate support structure.

In order to achieve the above-described object, a hole reinforcing member according to the present invention is a hole reinforcing member disposed in a through hole in which a grounding portion is provided on an outer peripheral portion of a circuit board, and is made of a conductive material and is grounded. It is in contact with the part so as to be elastically displaceable and is provided rotatably in the through hole. The hole reinforcing member includes a first member on which an elastic displacement piece that is in contact with the grounding portion is formed, and a second member that is engaged with the first member by sandwiching the circuit board.

  According to the hole reinforcing member configured as described above, when a screw tightening torque is generated when the circuit board is fixed to the support member with the screw, the hole reinforcing member is brought into contact with the grounding portion so as to be elastically displaceable and penetrated. Since the hole reinforcement member is rotatably provided, the hole reinforcement member rotates well with respect to the through hole in a state in which the contact state between the hole reinforcement member and the grounding portion is maintained well, so that the screw tightening torque Is suppressed from being loaded on the circuit board. Therefore, when the circuit board is fixed to the support member with a screw, it is possible to prevent the circuit board from rotating with respect to the support member.

In addition, a board support structure according to the present invention includes a first circuit board that is electrically connected to the second circuit board via the connector portion, a support member that supports the first circuit board and is grounded, A screw for fixing the one circuit board to the support member, a through hole provided in the first circuit board through which the screw is inserted, and a grounding part provided on the outer periphery of the through hole for grounding the first circuit board; A hole reinforcing member having an insertion hole through which a screw is inserted and provided in the through hole. The hole reinforcing member is made of a conductive material, is in contact with the grounding portion so as to be elastically displaceable, and is rotatably provided in the through hole, and is formed with an elastic displacement piece that is in contact with the grounding portion. One member and a second member engaged with the first circuit board sandwiched between the first member and the first member.

  According to the substrate support structure configured as described above, the hole reinforcing member is provided in contact with the grounding portion so as to be elastically displaceable and rotatably provided in the through hole. Therefore, the first circuit board is used as the support member. When screw tightening torque is generated when fixing with screws, the hole reinforcing member is rotated well with respect to the through hole in a state where the contact state between the hole reinforcing member and the grounding portion is maintained well. It is possible to prevent the screw tightening torque from being applied to the first circuit board. Therefore, when the first circuit board is fixed to the support member with screws, it is possible to prevent the first circuit board from rotating with respect to the support member. Therefore, according to this board | substrate support structure, it is prevented that a connector part is damaged with a screwing torque, and the grounding state of a 1st rotation board and a 2nd rotation board is ensured favorably through a connector part.

  An electronic device according to the present invention includes the substrate support structure according to the above-described invention.

  A projection display device according to the present invention includes the above-described substrate support structure of the present invention and a projection optical system for projecting an image on a projection surface.

  As described above, according to the present invention, the circuit board is prevented from rotating with respect to the support member due to the screw tightening torque generated when the circuit board is fixed to the support member with a screw, and the grounding state of the circuit board is excellent. Can be secured.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in FIGS. 1 and 2, the projection display device according to the present embodiment includes a projection optical system 2 having a projection lens 6 for projecting an image onto a projection surface such as a screen, and a liquid crystal that displays the image to be projected. A display unit 3 having a display plate 7, a light source unit 4 having a lamp for emitting projection light, a power source unit 5 for supplying power to the display unit 3, the light source unit 4 and the like, the projection optical system 2 and each unit 3, 4 and 5, and a substrate support structure 10 for supporting and grounding circuit boards 11, 12, and 13 to be described later for controlling the respective parts 3, 4, and 5. . The support base 8 is formed of a conductive metal material, and a housing 9 is attached to the support base 8 and is electrically connected to a ground portion (not shown) of the projection display device.

  As shown in FIGS. 2, 3 and 4, the board support structure 10 includes a first circuit board for connecting a second circuit board 12 and a third circuit board 13 described later via connector portions 11c and 11d. 11, a second circuit board 12 on which various control circuits are mounted, a third circuit board 13 provided with a socket 9 to which the liquid crystal display plate 7 of the display unit 3 is connected, and each of these circuit boards 11, 12, 13, a support frame 15 that supports the first circuit board 11, a fixing screw 16 that fixes the first circuit board 11 to the support frame 15, and a hole reinforcing member 17 that is rotatably provided in a through hole 11 a described later of the first circuit board 11. And.

  As shown in FIG. 6, the first circuit board 11 is provided with a through hole 11 a through which a fixing screw is inserted, and a circular shape for grounding to the outer peripheral portion of the through hole 11 a via the support frame 15. A grounding surface 11b is provided. The through hole 11a is rotatably provided with a hole reinforcing member 17 that is a so-called eyelet for reinforcing the through hole 11a.

  The first circuit board 11 is provided with a first connector 11c and a second connector 11d that are electrically connected to the second circuit board 12 and the third circuit board 13, respectively, at both ends. Yes.

  The main surface of the second circuit board 12 is arranged orthogonal to the main surface of the first circuit board 11 and is fixed to the support frame 15. Further, the second circuit board 12 is provided with a connector part 12a fixed to one end part thereof, which is connected to the first connector part 11c of the first circuit board 11. A plurality of connection pins 12b are soldered and joined to the connector portion 12a.

  The third circuit board 13 has a main surface arranged orthogonal to the main surface of the first circuit board 11 and is fixed to the support frame 15. Therefore, the second circuit board 12 and the third circuit board 13 are arranged in parallel with each other, and a predetermined facing interval is provided by the support frame 15.

  The third circuit board 13 is provided with a connector part 13a fixed to one end of the third circuit board 13 to be connected to the second connector part 11d of the first circuit board 11. The third circuit board 13 requires a relatively large number of connection pins to output a high-definition video signal from the second circuit board 12 to the liquid crystal display board 7 on the liquid crystal display board 7, and a large number of connector pins 13a are provided on the connector section 13a. The connecting pins are soldered and joined.

  As shown in FIG. 5, a plurality of connection pins 13 b are arranged on the connector portion 13 a of the third circuit board 13 with a pitch of about 0.5 mm, for example. The connection pins 12b of the connector portion 12a of the second circuit board 12 are also formed in the same manner as the connection pins 13b in pitch and dimensions. Therefore, it is difficult for the connector portions 12a and 13a to increase the mechanical strength of the soldering portions of the connection pins 12b and 13b, and it is necessary to consider that stress is not applied to the soldering portions of the connection pins 12b and 13b as much as possible. is there.

  The third circuit board 13 is provided with a socket 9 to which the liquid crystal display plate 7 of the display unit 3 is electrically connected. In a state where the liquid crystal display plate 7 of the display unit 3 is electrically connected via the socket 9, the liquid crystal display plate 7, the socket 9 and the third circuit board 13 are pressed against the support base 8 by the support frame 15 and screwed. It is fastened and fixed.

  The support frame 15 is formed of a conductive metal material such as aluminum, for example, and is electrically connected to a ground portion (not shown) via the support base 8 and grounded.

  The support frame 15 is provided with a prismatic support portion 15 a that supports the vicinity of the through hole 11 a of the first circuit board 11. The support frame 15 is assembled to the support base, and is electrically connected to a ground portion (not shown) of the projection display device. The fixing screw 16 is formed of a conductive metal material and is tightened into a screw hole (not shown) of the support portion 15a of the support frame 15.

  As shown in FIG. 6, the hole reinforcing member 17, which is a main part of the substrate support structure 10 of the present embodiment, is a pair of first metal fitting 21 and second metal fitting 22 that are combined so as to sandwich the first circuit board 11. have. The first metal fitting 21 and the second metal fitting 22 are formed of a conductive material such as a metal material, for example, and have a mechanical strength such that the first metal fitting 21 and the second metal fitting 22 are not crushed by the thrust of the fixing screw 16 by a screw tightening torque. .

  As shown in FIGS. 7 and 8, the first metal fitting 21 includes an annular fitting portion 21a fitted to the second metal fitting 22, and a plurality of sliding contact pieces which are slidably contacted on the grounding surface 11b. 21b.

  Each sliding contact piece 21b is supported on the outer peripheral portion of the fitting portion 21a with an interval in the circumferential direction of the fitting portion 21a. At one end of each sliding contact piece 21b, a sliding contact claw 21c that is slidably contacted on the grounding surface 11b is formed to be bent substantially perpendicular to the grounding surface 11b. Each sliding contact piece 21b is supported so as to be elastically displaceable in a direction in which the sliding contact claw 21c approaches and separates from the ground surface 11b.

  The second metal fitting 22 is slidably contacted with the cylindrical fitting portion 22a into which the fitting portion 21a of the first metal fitting 21 is inserted and fitted, and the back surface of the grounding surface 11b provided on the first circuit board 11. Flange portion 22b. The fitting portion 22a has an insertion hole 22c through which the fixing screw 16 is inserted. Further, the outer diameter of the fitting portion 22a inserted through the through hole 11a is formed to be slightly smaller than the inner diameter of the through hole 11a, and the hole reinforcing member 17 can be smoothly rotated with respect to the through hole 11a. Yes.

  The first fitting 21 has a fitting portion 21 a inserted through the through hole 11 a of the first circuit board 11, and the fitting portion 21 a is press-fitted into the fitting portion 22 a of the second fitting 22. It is fixed to the through hole 11 a of the circuit board 11. Therefore, the hole reinforcing member 17 is provided with the first circuit board 11 sandwiched between the first metal fitting 21 and the second metal fitting 22.

  As shown in FIG. 8, the hole reinforcing member 17 rotatably provided in the through hole 11 a is configured such that each sliding contact piece 21 b of the first metal fitting 21 is on the ground surface 11 b of the first circuit board 11. Instead of surface contact, line contact is made at the ridge line (corner of the tip) of the sliding contact claw 21c, and each sliding contact piece 21b is elastically displaced and flexed to be reliably contacted with a predetermined pressing force.

  In the substrate support structure 10 configured as described above, when the first circuit board 11 is electrically connected to the second circuit board 12 and the third circuit board 13, respectively, as shown in FIGS. The connector parts 11c and 11d and the connector parts 12b and 13b are connected to each other by being placed on the support part 15a of the support frame 15 that supports the second circuit board 12 and the third circuit board 13, respectively. The first circuit board 11 is connected to the second circuit board 12 and the third circuit board 13 to prevent the connection state between the connector parts 11c and 11d and the connector parts 12b and 13b from being removed. The support frame 15 is fixed to the support portion 15 a by being fastened with a fixing screw 16.

  In the board support structure 10 of the present embodiment, the screw tightening torque generated when the first circuit board 11 is fixed to the support frame 15 with the fixing screw 16 acts on the hole reinforcing member 17 provided in the through hole 11a. Even in this case, since the hole reinforcing member 17 smoothly rotates with respect to the through hole 11a of the first circuit board 11, no rotational force is transmitted to the first circuit board 11, and the first circuit board 11 itself is not transmitted. No rotational force is generated on the support frame 15. For this reason, the connector parts 11c and 11d of the first circuit board 11 are soldered to the connection pins 12b and 13b having relatively small mechanical strength on the connector parts 12a and 13a side of the second circuit board 12 and the third circuit board 13. Since no stress is applied to the attaching portion, it is possible to prevent the soldering portion from being cracked and to prevent the connection pins 12b and 13b from being damaged.

  Further, even when the hole reinforcing member 17 is rotated with respect to the first circuit board 11, the sliding contact piece 21b of the second metal fitting 21 is in contact with the first circuit board 11 so as to be elastically displaceable. The connection state with respect to the ground plane 11b of the board | substrate 11 is maintained favorable. Accordingly, the ground plane 11 b of the first circuit board 11 for grounding the second circuit board 12 and the third circuit board 13 is electrically connected to the support frame 15, and the projection display is provided via the support base 8. The electrical connection state with the grounding part of the device is maintained well.

  In addition, as shown in FIG. 1, the projection display device of the present embodiment is provided with a fourth circuit board 14 on which various control circuits are mounted on one side of the support base 8. In the projection display device, the support frame 15 is provided with a first fan 26 and a second fan 27 that cool the second circuit board 12 and the third circuit board 13, respectively. The projection display device is provided with a third fan 28 for cooling the fourth circuit board 14.

  As described above, according to the substrate support structure 10 included in the projection display device of the present embodiment, the hole reinforcing member 17 made of a conductive material is applied to the ground surface 11b of the first circuit substrate 11 so as to be elastically displaceable. When the first circuit board 11 is fixed to the support frame 15 with the fixing screws 16, the connection pins 12b of the second circuit board 12 and the third circuit board 13 are provided. The connection pin 13b is not subjected to a load due to screw tightening torque, and it is possible to suppress the occurrence of cracks in the soldered portions of the connection pins 12b and 13b. Further, according to the substrate support structure 10, the second circuit board 12 and the third circuit board 13 are stably and electrically connected to the ground portion of the projection display device via the first circuit board 11. Therefore, good EMI characteristics can be ensured.

  According to the projection display device of the present embodiment, it is possible to improve the reliability of the connection state by the connector portion in which the failure such as the connection failure is relatively likely to occur and the number of connection pins is relatively large. By using such a connector portion, for example, a space required for electrical connection between a circuit board for processing a video signal and a liquid crystal display panel can be reduced.

(Other embodiments)
In the above-described embodiment, the hole reinforcing member 17 included in the board support structure is configured by combining two parts of the pair of the first metal fitting 21 and the second metal fitting 22, but a single component as necessary. Of course, it may be comprised from.

  As shown in FIG. 9, the other hole reinforcing member 27 includes a cylindrical portion 27a provided with an insertion hole 27d through which the fixing screw 16 is inserted, and a plurality of sliding contacts that are slidably contacted on the ground surface 11b so as to be elastically displaceable. It has the piece 27b and the flange part 27c slidably contacted with the back surface of the grounding surface 11b, and consists of a metal fitting which is a single component. Even if the hole reinforcing member 27 is configured to be rotatably crimped to the through hole 11a of the first circuit board 11, the same effects as those of the above-described embodiment can be obtained.

It is a perspective view which shows the projection type display apparatus of this embodiment. It is a disassembled perspective view which shows the said projection type display apparatus. It is a perspective view which shows a board | substrate support structure. It is a disassembled perspective view which shows the state which removed the 1st circuit board from the board | substrate support structure. It is a perspective view which expands and shows the connector part of a 3rd circuit board. It is a disassembled perspective view which shows a hole reinforcement member. It is a perspective view which shows the state in which the hole reinforcement member was provided in the through-hole. It is sectional drawing which shows the state in which the hole reinforcement member was provided in the through-hole. It is sectional drawing which shows the hole reinforcement member of other embodiment. It is a perspective view which shows the conventional board | substrate support structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Board | substrate support structure 11 1st circuit board 11a Through-hole 11b Ground surface 11c 1st connector 11d 2nd connector 12 2nd circuit board 12a Connector part 12b Connection pin 13 3rd circuit board 13a Connector part 13b Connection pin 15 Support frame 16 Fixing screw 17 Hole reinforcing member 18a, 18b, 19, 20 Connector part 21 First metal fitting 21a Fitting part 22 Second metal fitting 22a Fitting part

Claims (9)

A hole reinforcing member disposed in a through hole provided with a grounding portion on an outer peripheral portion of a circuit board,
It is made of a conductive material, is in contact with the grounding portion so as to be elastically displaceable, and is rotatably provided in the through hole
A hole having a first member formed with an elastic displacement piece to be in contact with the grounding portion and a second member engaged with the circuit board sandwiched between the first member. Reinforcing member. The first member includes a fitting portion that is fitted to the second member, and a sliding contact portion that is in sliding contact with the grounding portion,
The hole reinforcing member according to claim 1, wherein the sliding contact portion is elastically displaceable . A first circuit board electrically connected to the second circuit board through the connector portion;
A support member that supports and grounds the first circuit board;
A screw for fixing the first circuit board to the support member;
A through hole provided in the first circuit board through which the screw is inserted;
A grounding portion provided on an outer peripheral portion of the through hole, for grounding the first circuit board;
An insertion hole through which the screw is inserted, and a hole reinforcing member provided in the through hole;
Said hole reinforcing member is made of a conductive material, it is provided rotatably in the through hole is resiliently displaceable in contact with the ground portion, elastic pieces being abutted to the ground portion is formed And a second member that is engaged with the first circuit board sandwiched between the first member and the first member . The first member includes a fitting portion that is fitted to the second member, and a sliding contact portion that is in sliding contact with the grounding portion,
The substrate support structure according to claim 3, wherein the sliding contact portion is elastically displaceable .   The board | substrate support structure of Claim 3 or 4 with which the said connector part is each fixed and provided in the said 1st circuit board and the said 2nd circuit board.   6. The substrate support structure according to claim 3, wherein a main surface of the first circuit board is disposed orthogonal to a main surface of the second circuit board.   The substrate support structure according to claim 3, wherein the first circuit board is electrically connected to the third circuit board via a further connector portion.   An electronic device comprising the substrate support structure according to claim 3. A substrate support structure according to any one of claims 3 to 7,
A projection display device comprising a projection optical system for projecting an image on a projection surface.

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