Electronic device and circuit module device

The invention comprises a connector provided at a predetermined position on a circuit board on which a predetermined circuit pattern is formed and electronic parts are disposed at positions which corresponds to the circuit pattern, a body with four faces which covers the circuit board such that the connector can be exposed to the outside, first and second planes which shield the circuit board positioned in the body with four faces together with the body with four faces, and a shield structure which electrically separates the portion for connection of the connector and the circuit pattern and electronic parts which are disposed at a position corresponding with the circuit pattern.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2003-400912, filed Nov. 28, 2003, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a circuit board for processing signals input via, for example a connector or a connector terminal; a circuit module device in which the unnecessary radiation which sometimes superposes with input or output signals from the signal terminal provided on the circuit board can be reduced; and a typical electronic device such as video recording device or a video display device.

2. Description of the Related Art

As is well known, conventionally, in order to reduce unnecessary radiation generated from the circuit module, the entire circuit module is covered with a electromagnetic wave shield such as a shield cover and the like, and a connection structure is widely used in which a hole is formed at the portion where the circuit module connects with an external circuit, and connection is done using a connection cable or the like from the hole.

A connection structure is also widely used which connects by exposing the connecting parts such as the connector and the like at the external parts of the shield structure.

It is to be noted that a connecting structure which fixes a connector from the back face of a board onto a board installed at a predetermined position in a shield case, and which is used the connection of the electrode which penetrates the front face of the board with the exterior (example, Jpn. Pat. Appln. KOKAI Publication No. 8-148877) is proposed as an example in which it is possible to shield from electromagnetic waves at a predetermined level, while connecting with signal wires from the exterior.

However, in the connection structure disclosed in Jpn. Pat. Appln. KOKAI Publication No. 8-148877, the circuit portion of the circuit module is not completely shielded, and in order to shield the circuit portion, it is necessary to expose the connector portion at the exterior portion of the shield case, and this causes the problem of increased size of the board.

Furthermore, in this connection structure disclosed in Jpn. Pat. Appln. KOKAI Publication No. 8-148877, an opening portion is necessary for connection with the external circuit, and there is the problem that there is unnecessary electromagnetic wave leakage from this opening portion.

BRIEF SUMMARY OF THE INVENTION

According to one aspect of the present invention, there is provided a circuit module device comprising: a connector provided at a predetermined position on a circuit board on which a predetermined circuit pattern is formed and electronic parts are disposed at positions which correspond to the circuit pattern; a body with four faces which covers the circuit board such that the connector can be exposed to the outside; first and second planes which shield the circuit board positioned in the body with four faces together with the body with four faces; and a shield structure which electrically separates the portion for connection of the connector and the circuit pattern and the electronic parts which are disposed at a position corresponding with the circuit pattern.

According to another aspect of the present invention, there is provided an electronic device comprising: at least a connector provided at a predetermined position on a circuit board on which a predetermined circuit pattern is formed and electronic parts are disposed at positions which corresponds to the circuit pattern; a body with four faces which covers the circuit board such that the connector can be exposed to the outside; first and second planes which shield the circuit board positioned in the body with four faces together with the body with four faces; and a shield structure which electrically separates the portion for connection of the connector and the circuit pattern and the electronic part which is disposed at a position corresponding with the circuit pattern.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of this invention is described in detail with reference to the drawings in the following. As shown inFIG. 1, the circuit module10which is incorporated into electronic devices such as a video recording device or video playing device, or a television receiver or computation device has a circuit module board (simply referred to as circuit board hereinafter)11which has circuit or circuit structure such as an LSI and the like which is capable of performing predetermined operations such as signal processing or computations, or encoding and decoding and the like.

A connector12used for connecting the circuit board11with an external circuit, and electronic parts (active device or passive devices)13used for predetermined operations of the circuit board11are disposed at predetermined positions on the circuit board11so as to match a circuit pattern which is not described in detail.

The circuit board11is covered by a shield case (simply referred to as shield hereinafter)20for preventing leakage of electromagnetic waves generated by the circuit board11to the outside, and to prevent electromagnetic waves or static electricity (outside noise) from the outside from reaching the circuit board11.

The shield20is formed in a substantially rectangular shape, from a case21which is orthogonal to the plane direction of the circuit board11, and substantially formed with four faces enclosing the four sides of circuit board11, and a first (upper) plane portion22and a second (lower) plane portion23which contact the case21parallel to the plane direction of the circuit board11from the top and bottom of the case21. It is to be noted that edge portions24are formed so as to extend from each of the four faces configuration of the case21at a predetermined length generally in parallel with the plane direction of the circuit board11, and so as to be capable of contacting the upper plane portion22and the lower plane portion23respectively, and thereby improve the shielding effect.

An opening25for connecting the connector12that is positioned at a predetermined position on the circuit board11, with an external circuit which is not shown (or with a wire such a flat cable and the like) or with an external device, is provided in a region where the connector12is exposed on a suitably selected side of the case21.

The terminal of the opposite side (unexposed side) of the connector12which is exposed from the opening25, that is, the inner side portion (board mounting portion) of the circuit board11of the connector12extends so that a part of the edge portion24of the case21is parallel to the circuit board11, and the portion that is closer to the center of the plane direction of the circuit board11than the connector12is bent toward the circuit board11substantially at the cover position, and the connector shield26is thereby formed.

The connector shield26contacts (is fixed to) the circuit board11at the portion where the circuit pattern (shown by the dotted line inFIG. 2) on the circuit board11connects with the connector12, that is, at a predetermined position which is closer to the center in the plane direction of the circuit board11than the connection region (connection position) where the terminal (contact)120of the connector12which is not described in detail, connects with the through hole112which is not described in detail, of the circuit board11.

The front end of the connector shield26has a suitably selected number of ribs27formed at a portion of the connector shield26which extends and has a predetermined width. It is to be noted that the connector shield26and the ribs27are provided at four faces excluding the face at opening25side and face for connection or contact on the circuit board11, assuming that the connector12is a rectangle. In addition, as shown inFIG. 3, the shield26and the ribs27are integrally formed with the case21and the edge24in a state in which the case21and the edge24of the case21are open. It is to be noted that the ribs27may be omitted.

The ribs27are fixed to the circuit board11by being inserted into rib receivers (openings formed as apertures or slits which correspond to the rib configuration) which is not described in detail and are formed in advanced on the circuit board11. The ribs27are also fixed being soldered in a land region which is formed in advance at the same time as the wire pattern of the circuit board11in a state of being inserted therein.

That is, by forming the rib27, the adverse effects caused by the shield20contacting the circuit board11or the connector12and the like are prevented. It is to be noted that when the land region is grounded, the entire shield20is also grounded and thus undesired radiation to the exterior of the electromagnetic waves generated by the electronic parts that are disposed on the circuit board11is prevented. Furthermore adverse effects on the circuit board11due to external noise caused by electromagnetic waves or static electricity from the exterior are reduced.

According to the above described circuit module10, undesired radiation of electromagnetic waves from the circuit board11to the exterior is prevented. Also it becomes possible to dispose electronic parts in the space on the circuit board11, which is near the connector shield26, which covers the area around the connector12, and thus the mounting density of the electronic parts is improved and the size (area) of the circuit module10is reduced.

It is to be noted that when the circuit module10inFIG. 1is a tuner circuit which is included in video recording devices or video playing devices or television receivers the connector12may for example be an RF connector, a pin plug or a RCA connector. In the case where the circuit module10shown inFIG. 1is for example, a personal computer or the like, the connector12may be a digital terminal which includes a parallel interface (RS232C and the like) or IEEE1394, or a USB interface.

FIGS. 4 and 5show another structure of the circuit module described usingFIG. 1. It is to be noted that the elements shown inFIG. 1which are substantially the same or similar have been assigned the same numbers and detailed descriptions thereof are not repeated.

As shown inFIGS. 4 and 5, the circuit module110has a first circuit module board (simply referred to as circuit board hereinafter)111which has a circuit or a circuit structure such as an LSI which is capable of performing predetermined operations and a second circuit module board (simply referred to a second circuit board hereinafter)151which is laminated at a suitably selected position on the circuit board111.

The connector12and the electronic parts13and the like are arranged at predetermined positions on the circuit board11so as to match the circuit pattern. Connection patterns or ground patterns which are used for sending and receiving signals to the circuit board111, and to and from the second circuit board151are also formed.

The circuit board111is covered by a shield case (simply referred to as shield hereinafter)20. It is to be noted that the second circuit board151may also be independently shielded, for example, by a second shield case (simply referred to as second shield hereinafter)170.

The shield20is substantially configured as a rectangle, from a case21, and is substantially four face configuration enclosing the four sides of the circuit board111, and a plane (upper plane) portion22and a second plane (lower plane) portion23which contact the case21in parallel with the plane direction at the top and bottom of the case21. It is to be noted that and edge portion24is formed from each face formed with four faces of the case21, and the edge portion24extends by a predetermined length, generally in parallel with the plane direction of the circuit board11such that the upper plane portion22and the lower plane portion23can contact each other, and the shielding effect is thereby increased.

An opening25for connecting the connector12that is positioned at a predetermined position on the circuit board111, with an external circuit which is not shown (or with a wire such a flat cable and the like) or with an external device, is provided in a region where the connector12is exposed on a suitably selected side of the case21.

The terminal of the opposite side (unexposed side) of the connector12which is exposed by the opening25, that is, the inner side portion (board mounting portion) of the circuit board111of the connector12extends so that a part of the edge portion24of the case21is parallel to the circuit board111, and the portion that is closer to the center of the plane direction of the circuit board111than the connector12is bent toward the circuit board111substantially at the cover position, and the connector shield26is thereby formed.

The front end of the connector shield26has a suitably selected number of ribs27formed at a portion of the connector shield26which extends and has a predetermined width. It is to be noted that the connector shield26and the ribs27are formed on four faces excluding the face at opening25side and the face for connection or contact on the circuit board111when the connector12is assumed to be a rectangle.

In addition, in the circuit module110which is shown inFIGS. 4 and 5, the contact153which is used for connecting the second circuit board151and the circuit board111is connected to a predetermined circuit pattern formed in advance in the back face of the base material of the second circuit board151, the other terminal is connected by the contact152(with the circuit board111) via the through hole (opening)114which is formed between the position connected to the contact120of the connector12fixed to the circuit board111and the fixing position where the connector shield26is fixed to the circuit board111.

That is, as shown inFIG. 4, there is the possibility that the second circuit board151becomes a source of unnecessary radiation for the circuit board111, and also in many cases, the second circuit board151needs to be shielded from external noise more than the circuit board111, and thus the portion of connection of both boards are placed closer to the case21side than the connector shield26so that the possible unnecessary radiation generated at the portion of connection with the circuit board111does not affect the second circuit board151.

It is to be noted that when there is a connection region in the circuit pattern (which is not described in detail) of the second circuit board151(shown by the dotted line inFIG. 5), it is necessary to securely ground the ground region of the second circuit board151via the circuit board111or the shield20. As a result, even if the ground pattern is in a region other that the connection portion defined between the abovementioned connector shield26and the circuit board111, it must be securely connected.

As described above, according to the above-described circuit module110, undesired radiation of electromagnetic waves from the circuit board111or the second circuit board151to the exterior is prevented. Furthermore, the unnecessary radiation generated at the circuit board111is prevented from reaching the second circuit board151.

FIG. 6is a schematic block diagram showing the case in which a cable modem module is used an example of the electronic device including the circuit module shown usingFIGS. 1 and 4.

The cable modem module (circuit module)210comprises an RF connector (coaxial connector)251to which an RF (coaxial) cable is connected which is used for sending and receiving signals to and from the center station (cable television (CATV) broadcast station); a circuit board211on which is disposed various circuits and function blocks which are described hereinafter; a tuner section222for processing high frequency signals input and output by the RF connector251; an A/D converter223for converting the down signals (analog signals) which have been subjected to frequency conversion via the tuner section222to digital signals; a demodulator section224for demodulating the down signals which have been converted to digital signals via the A/D converter223and forming them into data; a MAC (Media Access Control) section225for generating up signals (digital signals); a D/A converter226for converting the up signals generated by the MAC section225to analog signals; an interface (connector)227which includes Ethernet specifications and the like for outputting down signals input to the MAC section225to external devices; a main controller (microcomputer)228for controlling the operation of each of the circuits and function blocks; and memory229and the like.

That is, by forming the circuit board211with a circuit module shielded by the shield described using theFIG. 1orFIG. 4, undesired radiation of electromagnetic waves generated from the electronic parts disposed on the circuit board211of the module210from the connector (interface)227is prevented. Furthermore, the adverse effect on the circuit board211due to external noise caused by electromagnetic waves or static electricity from the exterior is reduced.

It is to be noted that, although a detailed descriptions thereof is not given, it is needless to say that in the cable modem module210, for which an example is shown inFIG. 6, selection of receiving channels (programs) and sending and receiving of mail to and from the center station is possible through control signals from a remote terminal (remote controller) which is operated from a remote location and is not shown.

Also, although they are not shown, it is needless to say that a video output terminals which outputs video signals to brown tubes (television receiver) or a display device for example, and a audio terminals which outputs audio signals to a television monitor device a audio amplifying device (audio amplifier) may be included.

FIG. 7is a schematic block diagram showing the case where a video recording and playing device is used as an example of the electronic device including the circuit module shown usingFIGS. 1 and 4.

InFIG. 7, the video recording and playing device (DVD recorder with hard disk)301has a television tuner321which selectively receives broadcast signals from predetermined channels and an external input terminal322which can input video signals and audio signals. The video signals and audio signal which are input from the exterior are input to the video decoder331and the audio A/D converter332respectively.

When video and audio are being recorded, the video signals and audio signals converted to digital signals by the video decoder331and the audio A/D converter332are encoded (compressed) to MPEG format data by the MPEG encoder333.

The video signals and audio signals compressed (encoded) are stored on the hard disk drive (HDD)335via the disk controller334.

Also, the video signals and audio signals compressed (encoded) are stored on a DVD-RAM disk (D) which is loaded beforehand in the DVD disk device336via the disk controller334.

When the video and audio are played, the MPEG signals (compressed signals) that are input to the MPEG decoder337are read from the HDD335or the disk (D), and MPEG signals (compressed signals) input to the MPEG decoder337are decoded by the MPEG decoder337, and converted to analog video signals and analog audio signals via the video encoder338and the audio D/A converter339.

The analog video signals and audio signals from the video encoder338and the audio D/A converter339are output to the terminals of the video output351and the audio output352respectively.

That is, by connecting a television receiver which can play video or audio, or a video display device (monitor device) and an audio amplifier or the like to the terminals of the video output351and the audio output352respectively, video and audio output from the video recording and playing device301are played.

It is to be noted that circuits or units of each of the video decoder331, the MPEG encoder333, the disk controller334, the MPEG decoder337, the video encoder338and the like is controlled by a main controller which is the microcomputer341.

A timer computer342is connected to the microcomputer341.

Even when the main power source circuit (not shown) of the video recording and playing device301is in the OFF state, the timer computer342turns on the power source at a preset time, or at a predetermined time before the preset time, and each main component of the device301is on standby in a state in which recording is possible, before the starting time for the reserve recording.

As a result, when the time for reserve recording arrives, the broadcast (program) or video and audio on the channel for which recording is reserved, are recorded using the preset conditions.

It is to be noted that a main body operation panel (operation panel)343for inputting control signals for operation of the video recording and playing device301such as starting of recording, video playing, stopping (of recording and playing), skipping (during playing), time setting/inputting of reserve time, inputting reserve conditions, and turning the main power source on and off, is connected to the timer computer342.

A remote control receiver344which receives various control signals input by the remote controller R is connected to the control panel343, and control signals corresponding to the inputting of control signal from the remote controller R to the operation panel343can also be input at a position which is away from the main body of the device301.

It is to be noted that the circuit module structure shown inFIG. 1orFIG. 4which is in the video recording and playing device (DVD recorder with hard disk)301, is any one of, or a suitable combination of a suitably selected number of units or circuits, stored in a shield (not shown) as a single unit. Examples of the units or circuits include the television tuner321, the external input322, the video decoder331, the audio A/D converter332, MPEG encoder333, the disk controller334, the MPEG decoder337, the video encoder338, the audio D/A converter339, the video output351, the audio output352, the microcomputer341, the timer computer342, or the remote control receiver344and the like. Also, a plurality of circuit modules may be provided in a main port which is not shown.

That is, as shown in the example of the dotted line (circuit module310), the single dot broken line (circuit module311) or the double dot broken line (circuit module312), in the region where there is a circuit board including a specific circuit or unit as well as connecter types, by shielding the circuit module with a shield structure as shown inFIG. 1orFIG. 4, undesired radiation of electromagnetic waves generated from the electronic parts used in suitably selected units or circuit boards to the outside is prevented. Furthermore, the adverse effect on the unit or circuit due to external noise caused by electromagnetic waves or static electricity from the exterior is reduced. It is to be noted that, for the television tuner321and the like on which external noise caused by electromagnetic waves or static electricity from the exterior tend to have an adverse effect, it is preferable that the double shield shown inFIG. 4in particular is used.

FIG. 8describes an example of a personal computer as the electronic device which includes the circuit module ofFIGS. 1 and 4.

As shown inFIG. 8, the personal computer401is a known integrated system in which an external case402, a main circuit board (mother board) which is not shown, a key board (input terminal)404, a power source device405and a display device406are formed as a single unit.

The mother board comprises a disk drive407used for installing applications for example, a hard disk drive device (HDD) as the main storage device, a communications unit408which is used for communication with the outside and for transferring large data sets, and a television tuner (not shown) which is becoming a standard present day device, and the like.

It is to be noted that when the disk drive device407is a recording medium on which video or audio is recorded in the installed disk, the recorded audio and video may be played. The mother board is not described in detail but a unit or circuit board which includes a video board or a main body which is a typical audio playing device, and an input and output port and interface or the like used for connecting typical peripheral devices such as a printer and scanner.

As shown inFIG. 8, in the personal computer401, the circuit module structure ofFIG. 1andFIG. 4is widely used as one in which for example, a communication unit408, a television tuner (not shown), a video board, units or circuits which are typical audio playing devices are integrally stored in the shield.

That is, by using a circuit module which is shielded by the shield structure shown inFIG. 1orFIG. 4as the circuit board included in a specific circuit or unit, undesired radiation to the outside of electromagnetic waves generated from the electronic parts used in the suitably selected unit or circuit is prevented. Furthermore, the adverse effect on the units or circuits due to external noise caused by electromagnetic waves or static electricity from the exterior is reduced. It is to be noted that for the communication unit408or the television tuner (not shown) and the like on which external noise caused by electromagnetic waves or static electricity from the exterior tend to have an adverse effect, it is preferable that the double shield shown inFIG. 4in particular is used.

FIG. 9is an example of the case in which a game machine is used an example of the electronic device including the circuit module described usingFIG. 1andFIG. 4.

The game machine501shown inFIG. 9comprises an external case502, a main circuit board503, a light source circuit board504, a front panel506and a rear panel507and the like, and a cable modem unit510is provided at a predetermined position on the inside the game machine. It is to be noted that the front panel506is not described in detail, but it may be connected to the controller (input device)505.

The game machine501shown inFIG. 9also has a hard disk device (HDD) on which game software which is downloadable from the center station or version updating data or high score data can be stored or a communication unit and the like in which communication with a suitably selected competitor entered by the center station can be maintained or cut off.

It is to be noted that a disk drive device or card (cartridge) slot may be included so as to be integral, when the main portion of the game software is provided via a DVD specified disk medium or a particular specified storing medium (cartridge or card).

It is also to be noted that the main circuit board503is not described in detail, but it comprises a cable modem unit510at a predetermined position, including the circuit board511which is shielded in the same manner as that shown usingFIG. 1orFIG. 4.

Furthermore, because the cable modem unit510is shielded by the shield520and the upper cover (upper face)522and the lower cover (lower face)523, input of unnecessary external radiation to the circuit board511, and output of the unnecessary radiation from the circuit board511to the outside of the cable modem unit510is reduced.

As described above, in the electronic device and the circuit module of the present invention, the connector which is at a predetermined position on the circuit board, that is, at the portion where the circuit board and the connector connects, is shielded by a connector shield which is formed by one portion of the case of the shield case (four faces) which shields the area around the circuit board being bent.

Accordingly, the adverse effect on the circuit board due to external noise caused by electromagnetic waves or static electricity from the exterior can be reduced without increasing the number of parts or increasing the cost, and undesired radiation of electromagnetic waves from the circuit board to the exterior is prevented.

It is to be noted that because the connector shield is fixed to the circuit board by the ribs, undesirable results such as the shield coming in contact with the circuit board is prevented despite the simple structure in which a portion of the shield case is bent. In this case, by connecting the rib and the land (ground portion) of the circuit board, ground of the shield case can also be ensured.

In addition, it is also possible to dispose electronic parts in the space on the circuit board which is near the connector shield, and as a result, the mounting density of the electronic parts is improved and the size (area) of the circuit module10is reduced.

Thus, it becomes possible to send and receive high level signals and generation of undesired radiation (noise) to the exterior is prevented.

That is, according to the present invention, by covering the circuit module with an electromagnetic wave shield (shield case), unnecessary electromagnetic wave noise that is radiated from the circuit module can be emitted to the outside; the circuit module can be shielded from the unnecessary electromagnetic waves which are generated; the circuit module can be shielded from unnecessary electromagnetic waves noise from external circuits; and the shield case can be grounded at a stable ground potential.

It is to be noted that the present invention is not to be limited by the above-described embodiment and the various modifications may be made to the structural elements without departing from the scope of the invention. Furthermore, various inventions may be formed by suitably combining the plurality of elements disclosed in the above-described example. For example, some structural elements may be eliminated from the structural elements disclosed in the example. Also, structural elements from other examples may be suitably combined.