JP2006339361A - Substrate support structure and electronic apparatus including substrate supported thereby - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate support structure whose connector is not influenced by external force, and also to provide an electronic apparatus including a substrate supported by that structure. <P>SOLUTION: A DMD substrate 3 is fixed to a vertical plane of an optical engine base 6. A main substrate 1 and the DMD substrate 3 are arranged perpendicularly to each other and are connected to each other by connectors 4 and 5. A projection 11 is integrally formed in the optical engine base 6. The main substrate 1 is fixed to the optical engine base 6 by a first screw 12 and a second screw 13, and the projection 11 of the optical engine base 6 is inserted into a hole 1a of the main substrate 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a circuit board holding structure in an electronic device and an electronic device having the circuit board. In particular, the electronic apparatus according to the present invention is a projection display device, and is a projection display device having a digital micromirror device (hereinafter abbreviated as DMD) as an image display element used in the projection display device.

  Electronic devices often use a plurality of circuit boards. These circuit boards are electrically connected by electrical connection parts such as a flexible board (FPC), wire wiring, and a connector. However, when the circuit boards are connected to each other with a rigid body such as a connector, if an external force is applied only to one of the circuit boards, a force is applied to the connector connecting the circuit boards to each other, resulting in poor contact of the connector part. This is a problem that occurs or the connector part is damaged. Therefore, by providing a board retainer that presses the circuit board in the direction in which the connector part does not come off, and a support that supports the board retainer, contact failure and damage to the connector part occur so that the circuit board does not shift due to vibration or impact. Patent Document 1 discloses a technique for preventing the above.

  Further, as another technique for preventing the contact failure and breakage of the connector portion, a substrate holding structure as shown in FIG. 7 has been conventionally used. Referring to FIG. 7, for example, in a conventional projection display device, a connection spacer 102 and a connector 103 are fixed on the upper surface of the first substrate 101. A protrusion 102 a is integrally formed on the upper end of the connection spacer 102. The second substrate 104 is attached to the connection spacer 102 substantially parallel to the first substrate 101, and the protrusion 102 a of the connection spacer 102 penetrates the second substrate 104. Further, the first substrate 101 and the second substrate 104 are connected by a connector 103. Further, an external terminal group 105 such as an RGB terminal and a video terminal is fixed to a mounting bracket connected to the ends of the first substrate 101 and the second substrate 104.

For example, when an RGB cable or the like is inserted into or pulled out from the external terminal group 105, a force is applied in the insertion / extraction direction of the cable or the like. However, since the first substrate 101 and the second substrate 104 are connected, the external force is simultaneously applied to both substrates. As a result, since the first substrate 101 and the second substrate 104 move simultaneously, no force is applied to the connector 103. Therefore, contact failure or destruction of the connector 103 does not occur due to the external force applied to the external terminal group 105.
JP 2002-111254 A

  However, with the technique described in Patent Document 1, it is difficult to reduce the size of the electronic device because a space is required for arranging the substrate retainer and the support on the side opposite to the connector portion of the circuit board. Moreover, it is difficult to dispose the substrate retainer and the support for the electronic device in which the components are arranged so densely that there is no extra space in the housing.

  The conventional substrate holding method using the connection spacer shown in FIG. 7 can be performed relatively easily when the circuit boards connected by the connectors are arranged in parallel with each other. When the sizes of the circuit boards are greatly different, or when the circuit boards are attached to each other vertically, the connection spacers cannot be arranged, which is difficult to implement.

  For example, in the case of a projection display device in which DMD is used as an image display element, the DMD substrate is very small compared to the main substrate and has a structure that must be connected to the main substrate in the vertical direction. As in the conventional example shown in FIG. 7, it is impossible to use a connection spacer that allows an external force to be simultaneously applied to the main substrate and the DMD substrate.

  Therefore, in the case of a projection display device using DMD as an image display element, a substrate holding structure as shown in FIG. 8 has been conventionally employed. According to FIG. 8, a metal optical engine base 201 manufactured by die casting is fixed to the bottom of the casing of the device, and the DMD substrate 202 is firmly fixed to the vertical surface of the optical engine base 201. Since the DMD is an electrical component as well as an optical component, high precision is required for its arrangement. Accordingly, the DMD substrate 202 is firmly fixed to the optical engine base 201 so as not to be displaced due to changes over time. A main board 203 is arranged vertically on the DMD board 202, and the DMD board 202 and the main board 203 are connected by a connector 204. The main board 203 is firmly fixed to the optical engine base 201 with a first screw 205 and fixed to another metal plate with a second screw 206. Further, the main board 203 is provided with an external terminal group 207 such as RGB terminals and video terminals.

  However, in the structure shown in FIG. 8, there is a concern that contact failure or breakage of the connector portion may occur. The reason will be explained.

  For example, when an RGB cable or the like is inserted into or pulled out from the external terminal group 207, a force is applied in the insertion / extraction direction of the cable or the like. At that time, a force that rotates the main board 203 within the plane acts on a portion firmly fixed to the optical engine base 201 by the first screw 205 of the main board 203 as a fulcrum. At this time, since the portion using the second screw 206 of the main board 203 is fixed to a metal plate that is not a rigid body like the optical engine base, it may move around the fulcrum. In this case, a force is applied to the connector 204, which is an electrical connection portion between the main board 203 and the DMD board 202, and there is a possibility that contact failure or breakage of the connector part may occur.

  SUMMARY OF THE INVENTION In view of the above-described problems of the related art, an object of the present invention is to provide a board holding structure in which a connector portion for connecting circuit boards to each other is not affected by an external force, and an electronic apparatus having the structure. is there.

  In order to achieve the above object, the present invention is a substrate holding structure for an electronic device having a first substrate and a second substrate, and a rigid body is connected to the housing of the electronic device. The first substrate is provided with terminals to which external terminals can be attached and detached. The second substrate is fixed to the rigid body. The first substrate and the second substrate are connected by a structure (for example, a connector). The first substrate is fixed to the rigid body at two or more locations.

  In such a structure, since the first substrate is fixed to the rigid body at two or more locations, an external force is applied to the first substrate when the external terminal is attached to or detached from the terminal provided on the first substrate. However, the first substrate does not rotate with respect to the rigid body. As a result, force concentration does not occur in the structure provided between the first substrate and the second substrate fixedly connected to the rigid body, and the connection state does not change.

  Another invention is a substrate holding structure which is partly different from the above invention. That is, the rigid body has a projection, the first substrate is fixed to the rigid body at one or more locations, and the cross section of the first substrate is in contact with the projection. In this structure, the first substrate is fixed to the rigid body at one or more places, and the cross section of the first substrate is brought into contact with the protrusions, so that the external terminals are attached to and detached from the terminals provided on the first substrate. In this case, even if an external force is applied to the first substrate, the first substrate does not rotate with respect to the rigid body. As a result, force concentration does not occur in the structure provided between the first substrate and the second substrate fixedly connected to the rigid body, and the connection state does not change.

  In this case, it is desirable that the first substrate has a hole and the protrusion is inserted into the hole.

  According to the present invention, even when an external force is applied to the terminal, the structure (for example, a connector) that connects the first substrate and the second substrate is not affected by the external force. Problems such as deterioration or damage of the structure do not occur. Thereby, an electronic device with improved reliability can be provided.

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

  FIG. 1 is a perspective view of an electronic apparatus having a substrate holding structure according to an embodiment of the present invention, and FIG. 2 is a perspective view in which the main substrate of FIG. 1 is shifted upward. All of the electronic devices mentioned in the present embodiment are projection display devices (so-called projectors), but the substrate holding structure according to the present invention is not limited to the projection display device and can also be applied to general electronic devices.

  1 and 2, the main board 1 has an external terminal group 2 such as an RGB terminal, a video terminal, and an audio terminal. Further, the main substrate 1 also has various semiconductor elements such as a control LSI, an image processing LSI, and an image element control LSI. The DMD substrate 3 has a digital micromirror device (DMD) which is an image display element. A first connector 4 is attached to the main board 1, and a second connector 5 is also attached to the DMD board 3. The main board 1 and the DMD board 3 are arranged vertically, and the first connector 4 and the second connector 5 are engaged with each other so that they are physically fixed. Further, both the boards are also electrically connected by connectors 4 and 5. Further, since the DMD is an electrical component as well as an optical component, the DMD substrate 3 having the DMD is firmly fixed to the optical engine base 6. The optical engine base 6 is made of magnesium by die-casting and is a strong block structure, and is fixed to the bottom of the casing of the projection display device.

  FIG. 3 is a top view of the electronic apparatus shown in FIG. 1, and is a view for explaining a problem solved by the present invention.

  In FIG. 3, various cables are attached to and detached from the external terminal group 2 on the main board 1. At this time, a force is applied to the external terminal group 2 in the direction of the white arrow, so that the force is concentrated on the connector connection region 7 connecting the main board 1 and the DMD board 3 (see FIG. 2). . As a result, the engagement state between the connectors 4 and 5 (see FIG. 2) is abnormal, or the electrical contact state between the connectors 4 and 5 is also abnormal. Such poor contact of the connector causes many problems such as abnormal operation of the DMD and stop of the operation of the DMD. Furthermore, it is a problem because the connector is also destroyed.

  In order to solve this problem, there is a method of strengthening the coupling force between the main board 1 and the DMD board 3 and adopting a structure that can withstand this force even when the force is concentrated on the connector portion. This method is problematic because the connector portion is enlarged, and there are many adverse effects such as an increase in the size of the substrate and the weight of the apparatus. This method can be performed relatively easily when both substrates are arranged in parallel, but the DMD substrate 3 is arranged perpendicular to the main substrate 1 as shown in FIG. In some cases, it is difficult to implement because the connector connection area cannot be made large.

  In view of this, the present inventors have invented a structure that indirectly reinforces the connection state between the main substrate 1 and the DMD substrate 3 instead of reinforcing the portion where the main substrate 1 and the DMD substrate 3 are directly connected. This structure can be applied when the DMD substrate 3 is arranged perpendicular to the main substrate 1 as shown in FIG. 1 or when there is a large difference in size between the two substrates.

  In order to indirectly reinforce the connection state between the two, they may be connected to the same structure, and the connection between the two may be strengthened via this structure. At this time, it is not preferable that the structure connecting the two is deformed. Incidentally, the DMD substrate 3 to which the DMD that is also an optical component is attached is fixed to the optical engine base 6. Since the optical engine base 6 is a magnesium structure made by die casting, it is ideal as a rigid body. Therefore, the optical engine base 6 can be used as a rigid body that increases the coupling force between the main substrate 1 and the DMD substrate 3. That is, if the main board 1 is fixed to the optical engine base 6 at two or more locations, even if an external force is applied to the main board 1, the main board 1 does not move, so that no force is concentrated on the connector portion. Further, the same effect can be obtained by fixing the main substrate 1 to the optical engine base 6 at one or more locations and bringing the projections that are a part of the optical engine base 6 into contact with the cross section of the main substrate 1. . When a force is applied to the main board 1, the main board 1 tends to move, but the movement of the main board 1 is restricted because the cross section of the main board 1 is in contact with the protrusions. Further, since the main board 1 is fixed to the optical engine base 6 at a place other than the protrusions, the main board 1 does not move on the protrusions. Therefore, since it can prevent that the main board | substrate 1 moves, it can avoid that force concentrates on a connector part.

  Further, the substrate holding structure of the present invention will be described in detail with reference to FIGS.

  4 is a schematic enlarged view of a mounting portion for attaching the main board of the optical engine base shown in FIG. 1, and FIG. 5 is a schematic enlarged view of a state where the main board is fixed to the board mounting portion of the optical engine base shown in FIG. 6 is a side view showing a state in which the main board and the DMD board are fixed to the optical engine base shown in FIG.

  A second connector 5 and a heat sink 8 are soldered to one surface of the DMD substrate 3. Further, the other surface of the DMD substrate 3 is firmly attached to the vertical surface of the optical engine base 6. A first screw receiving portion 9, a second screw receiving portion 10, and a cylindrical projection 11 are provided on the upper surface of the optical engine base 6. Since these are formed integrally with the optical engine base 6, they are a part of the optical engine base 6. In the state of FIG. 4, the operator or the assembly robot aligns the first connector 4 of the main board 1 and the second connector 5 of the DMD board 3 so that the first connector of the main board 1 is engaged. The connector 4 is inserted into the second connector 5 of the DMD board 3 from above to connect the main board 1 and the DMD board 3. The main board 1 has a circular hole 1a, and a protrusion 11 is inserted into the hole 1a. The protrusion 11 is provided at a predetermined position on the upper surface of the optical engine base 6, and the DMD substrate 3 is fixed to the vertical surface of the optical engine base 6 with high accuracy. Since the second connector 5 is soldered to a predetermined position of the DMD board 3, the position of the second connector 5 on the DMD board 3 is accurately known. Therefore, the position of the second connector 5 can be accurately known with reference to the protrusion 11. Similarly, since the position of the first connector 4 on the main board 1 can be accurately determined on the main board 1, the position of the hole 1 a of the main board 1 can be provided with reference to the first connector 4. By aligning the protrusion 11 and the hole 1a, the first connector 4 and the second connector 5 can be accurately aligned. As in the present embodiment, when the connectors 1 and 3 are connected using the connectors 4 and 5 and the connectors cannot be visually observed, it is difficult to engage the connectors. However, in the present invention, just by aligning the hole 1a of the main board 1 and the projection 11 of the optical engine base 6, the positions of the connectors 4 and 5 are also matched, so that the connectors 4 and 5 can be easily engaged with each other. .

  Further, since the optical engine base 6 has a first screw receiving portion 9 and a second screw receiving portion 10, the main board 1 is a metal screw using the screw receiving portions 9 and 10. The first screw 12 and the second screw 13 are fixed to the optical engine base 6. As described above, in addition to inserting one protrusion 11 into the main board 1, fixing the main board 1 to the optical engine base 6 is made stronger by screwing in two places. Because. However, in order to avoid concentration of force on the connector, one protrusion 11 has already been inserted into the main board 1, so the main board 1 may be screwed to the optical engine base 6 at one location. Of course, when the projection 11 is not provided, the main board 1 needs to be screwed at least in two places.

  The DMD substrate 3 is fixed to the optical engine base 6 with screws, and the ground (GND) of the DMD substrate 3 and the optical engine base 6 are electrically connected via the screws. Similarly, the main board 1 is fixed to the optical engine base 6 with screws, and the ground of the main board 1 and the optical engine base 6 are electrically connected via the screws. A large amount of electrical noise is generated from the DMD. To suppress this noise, it is effective to electrically connect the ground of the DMD board 3 and the ground of the main board 1 through the optical engine base 6 at the shortest distance. It is. That is, connecting the ground of the main board 1 to the optical engine base 6 by the first screw receiving portion 9 effectively works to suppress noise from the DMD. Therefore, it is desirable to fix the main board 1 to the optical engine base 6 by screwing to prevent force concentration on the connector at a location closer to the DMD. In the case of the present embodiment, the first screw receiving portion 9 corresponds to this.

  As described above, according to the substrate holding structure according to the present embodiment, the DMD substrate 3 is fixed to the optical engine base 6 that is firmly fixed to the device casing, and the main substrate 1 and the DMD substrate 3 are connected to the connector 4. , 5 and the main board 1 is fixed to the optical engine base 6 at two or more locations with screws, so that even if an external force is applied to the main board 1, the main board 1 does not rotate with respect to the optical engine base 6, No force concentration occurs at the connecting portion between the first connector 4 of the main board 1 and the second connector 5 of the DMD board 3.

  Further, the DMD board 3 is fixed to the optical engine base 6, the main board 1 and the DMD board 3 are connected by the connectors 4, 5, and the projection 11 is integrally formed on the optical engine base. 6 is fixed to one or more locations with screws, and the cross section of the main board 1 is in contact with the projections 11, so even if an external force is applied to the main board 1, the main board 1 does not move, and force concentration is exerted on the connectors 4 and 5. Does not occur.

1 is a perspective view of an electronic apparatus having a substrate holding structure according to an embodiment of the present invention. It is the perspective view which shifted the main board | substrate of FIG. 1 upwards. It is the figure which showed the external force application direction and the connector connection area | region used as a force concentration area | region in the electronic device of FIG. It is a schematic enlarged view of the attachment part which attaches the main board | substrate of the optical engine base shown in FIG. FIG. 5 is a schematic enlarged view of a state in which a main board is fixed to a board mounting portion of the optical engine base shown in FIG. 4. FIG. 5 is a side view of a state where a main board and a DMD board are fixed to the optical engine base shown in FIG. 4. It is a figure which shows the projection type display apparatus which has the conventional board | substrate holding structure. It is a figure which shows the projection type display apparatus which has another conventional board | substrate holding structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main board | substrate 1a Hole 2 External terminal group 3 DMD board | substrate 4 1st connector 5 2nd connector 6 Optical engine base 7 Connector connection area | region 8 Heat sink 9 1st screw receiving part 10 2nd screw receiving part 11 Protrusion 12 1st screw 13 2nd screw

Claims (10)

A first substrate provided with terminals;
A second substrate electrically connected to the first substrate via a structure;
A substrate holding structure for an electronic device having a rigid body to which the first substrate and the second substrate are connected,
A substrate holding structure in which the first substrate is fixed to the rigid body at two or more locations. A first substrate provided with terminals;
A second substrate electrically connected to the first substrate via a structure;
A substrate holding structure for an electronic device having a rigid body to which the first substrate and the second substrate are connected,
The rigid body has a protrusion;
The substrate holding structure, wherein the first substrate is fixed to the rigid body, and a cross section of the first substrate is in contact with the protrusion.   The substrate holding structure according to claim 2, wherein the first substrate has a hole, and the protrusion is inserted into the hole.   The substrate holding structure according to claim 1, wherein the first substrate and the second substrate are electrically connected via the rigid body.   The substrate holding structure according to claim 1, wherein the first substrate and the second substrate are substantially orthogonal to each other.   The substrate holding structure according to claim 1, wherein the rigid body is made of metal.   The substrate holding structure according to claim 1, wherein the structure is a connector.   An electronic apparatus having a substrate held by the substrate holding structure according to claim 1. An image display element control circuit on the first substrate;
The electronic device according to claim 8, wherein the second substrate includes the image display element. The electronic device is a projection display device,
The electronic apparatus according to claim 9, wherein the image display element is a digital micromirror device.

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