Mobile communication device

A mobile communication device equipped with a microphone, a receiver, a first circuit board which is provided with an antenna at the microphone side and a second circuit board opposing to the first circuit board, wherein the antenna has a first antenna part which is extended parallel to the edge of the first circuit board and a second antenna part which is extended from a free end of the first antenna part towards the second circuit board. The end of the second antenna part may also be extended in a direction parallel to the second circuit board so as to form a third antenna part. As a result, even if a user uses the device in a state with the receiver pressed against the ear, the antenna will not be affected by the user body and the antenna characteristics will not deteriorate.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2011-042494, filed on Feb. 28, 2011, the entire contents of which are incorporated herein by reference.

FIELD

The present application relates to a mobile communication device. In the embodiments which are explained below, a mobile phone which is designed to reduce the deterioration of characteristics of the antenna at the time of conversation is explained as an embodiment.

BACKGROUND

An openable wireless communication device having a movable housing and a fixed housing both of which are provided with circuit boards which are electrically coupled by a connecting part which is provided at the sides of the two circuit boards at the ends of the housings is disclosed in Japanese Laid-Open Patent Publication No. 2005-192055 (hereinafter referred to as JP-A-2005-192055). In the device disclosed in JP-A-2005-192055, due to the connecting part, the current vectors of the two circuit boards are oriented toward the power feed point of the antenna. Due to this, the ground parts formed at the two circuit boards are coupled by high frequency coupling, so the antenna characteristics are improved. This art is illustrated in JP-A-2005-192055.

In a mobile phone, to improve the antenna characteristics in the conversation state, improvement of the antenna characteristics in the conversation state where the mobile phone is in close contact with the user body, in particular, the head, is being studied. In this regard, up to now, when studying mounting of an antenna in a mobile phone, the antenna mounting has been studied while stressing the improvement of the antenna characteristics of the mobile phone when placed in free space. For this reason, the antenna characteristics sometimes deteriorated at the time of use of the mobile phone in close contact with the user body. For example, there are flip-type mobile phones and slide-type mobile phones which, in the closed state, have antennas which are carried in the housings at the user body sides at the time of conversation. In such a mobile phone, sometimes the high frequency current which flows through the housing which is positioned at the user body side at the time of conversation ends up being absorbed by the user body and therefore the antenna characteristics end up deteriorating. Even if employing the configuration described in JP-A-2005-192055 where the circuit boards of the movable housing and the fixed housing are connected by a connecting part, the electrical coupling degree was weak and control of the current vector of the high frequency current was difficult.

SUMMARY

A first configuration of the mobile communication device of the present application is a mobile communication device which has a first circuit board, a second circuit board which faces the first circuit board, and an antenna which is connected to the first circuit board, in which mobile communication device, the antenna has a first antenna part which is laid in a direction parallel to the first circuit board and a second antenna part which is laid in direction bent to a second circuit board side at the end of the first antenna part at a side far from the first circuit board.

A second configuration of the mobile communication device of the present application is a mobile communication device which has a first circuit board, a second circuit board which faces the first circuit board, and an antenna which is connected to the first circuit board, in which mobile communication device, the antenna has a first antenna part which is laid in a direction parallel to the first circuit board and a board extension part which includes an end of the second circuit board extended to a position right under the first antenna part.

A third configuration of the mobile communication device of the present application is a mobile communication device which has a first circuit board, a second circuit board which faces the first circuit board, and an antenna which is connected to the first circuit board, in which mobile communication device, the antenna has a first antenna part which is laid in a direction parallel to the first circuit board and a part which includes a conductor which is attached to an end of the second circuit board and which is positioned right under the first antenna part.

DESCRIPTION OF EMBODIMENTS

Below, modes of working the present application will be explained in detail based on specific embodiments using the attached drawings. Further, the same component members are explained while assigned the same reference notations.

FIG. 1andFIG. 2illustrate a lateral slide-type mobile phone10of one example of a mobile communication device according to a first aspect of the present application. The lateral slide-type mobile phone10is provided with a first housing comprised of an upper housing1and with a second housing comprised of a lower housing2.FIG. 1illustrates a state where the upper housing1is slid away from the lower housing2, whileFIG. 2illustrates a state where the upper housing1is superposed over the lower housing2and the phone is closed. Here, “lateral slide” means the upper housing1sliding in a short direction with respect to the lower housing2. The upper housing1sliding in the long direction with respect to the lower housing2is referred to as “longitudinal slide”. The lateral slide-type mobile phone10of the first aspect is provided with mobile phone functions at the upper housing1and computer-like electronic device functions at the lower housing2.

At the lateral slide-type mobile phone10, as illustrated inFIG. 1, input keys7which appear when the upper housing1is slid away from the lower housing2are provided at the lower housing2. At the upper housing1, there is a display4, receiver5, and microphone6. As the receiver5, a speaker is provided inside of the upper housing1. Further, as the microphone6, a microphone is provided inside of the upper housing1. Furthermore, inside of the top housing1near the microphone6, an antenna3is provided for sending and receiving signals. The thus configured lateral slide type mobile phone10, as illustrated inFIG. 3, is used in a closed state at the time of conversation. Note that, the antenna3does not need to be arranged near the microphone6.

In the lateral slide-type mobile phone10, as illustrated inFIG. 4andFIG. 5toFIG. 8, a flat antenna3is connected through a connection terminal13to the first circuit board11which is housed in the upper housing1. At the connection terminal13, a spring for feed of antenna power (not illustrated) is housed. The antenna3is arranged in parallel to the first circuit board11. At the back side of the first circuit board11, a baseband chip24which is provided with a telephone function is provided. Further, at the lower housing2, a second circuit board12is housed. The first circuit board11and the second circuit board12are connected by a flexible cable (FPC)15. Reference numeral14illustrates a connection part of the FPC15to the first circuit board11, while16illustrates a connection part of the FPC15to the second circuit board12.

In the thus configured lateral slide-type mobile phone10, there was the inconvenience that the antenna characteristics ended up deteriorating at the time of conversation. This inconvenience was due to the fact that in a mobile phone having an antenna for low frequency use of the 800 MHz band, the signal was emitted by running current through the housing as a whole, so when used in the state which is illustrated inFIG. 3, the high frequency current which flowed through the top housing ended up being absorbed by the user body (head)8. That is, if the current EC which flows through the first circuit board11which is illustrated inFIG. 4is large, the high frequency current which flows through the top housing1also becomes large and the effect of the user body becomes larger.

Therefore, in the present application, there is provided a mobile communication device of a first aspect wherein a top housing1slides in a lateral direction from a bottom housing2, in particular a lateral slide-type mobile phone10, wherein a current EC which flows through the first circuit board11is dispersed and a dispersed current ec flows through the second circuit board12. That is, in the present antenna, the voltage becomes maximum at the end of the antenna element, so by bending this end in a direction approaching the second circuit board12which is at the side far from the user body, the dispersed current ec flows through the second circuit board12.FIG. 9toFIG. 12illustrate basic first to fourth embodiments of the present application, whileFIG. 13toFIG. 16illustrate fifth to eighth embodiments comprised of combinations of the first to fourth embodiments.

FIG. 9is a partial cross-sectional view which illustrates the shape of an antenna3of a first embodiment of a lateral slide-type mobile phone10of the present application. In the first embodiment, an antenna3which is connected through a connection terminal13to the first circuit board11which is housed in the top housing1includes a first antenna part31and a second antenna part32. The first antenna part31is provided laid along an end21of the first circuit board11in a direction parallel to the first circuit board11, while the second antenna part32extends from the end of the first antenna part31and is bent to the second circuit board12side. The current EC which flows through the first circuit board11flows dispersed as the current ec to the second circuit board12due to this second antenna part32. Note that, the second antenna part32may be configured by a separate member from the first antenna part31and joined to the first antenna part31.

FIG. 10is a partial cross-sectional view which illustrates the shape of an antenna3in a second embodiment of a lateral slide-type mobile phone10of the present application. In the second embodiment, the antenna3which is connected through a connection terminal13to the first circuit board11which is housed in the top housing1includes a first antenna part31, a second antenna part32, and a third antenna part33. The first antenna part31is provided laid along an end21of the first circuit board11in a direction parallel to the first circuit board11, while the second antenna part32is provided extending from the end of the first antenna part31and bent to the second circuit board12side. Furthermore, a third antenna part33is provided extending from the end of the second antenna part32with this extension part bent in a direction parallel to the second circuit board12. The current EC which flows through the first circuit board11flows dispersed as the current ec to the second circuit board12due to this second antenna part32and third antenna part33.

Note that, the above-mentioned first antenna part31, second antenna part32, and third antenna part33may be formed by bending a single member or may be formed by preparing separate members and joining them together. The first antenna part31, second antenna part32, and third antenna part33are configured in the same way in the following embodiments as well.

FIG. 11is a partial cross-sectional view which illustrates the shape of the second circuit board12in a third embodiment of the lateral slide-type mobile phone10of the present application. In the third embodiment, the antenna3which is connected through a connection terminal13to the first circuit board11which is housed in the top housing1includes only a first antenna part31. On the other hand, the end22of the second circuit board12extends to a position right under the antenna3to provide a board extension part17. The current EC which flows through the first circuit board11flows dispersed as the current ec to the second circuit board12due to this board extension part17.

FIG. 12is a partial cross-sectional view which illustrates the shape of the second circuit board12in a fourth embodiment of the lateral slide-type mobile phone10of the present application. In the fourth embodiment, the antenna3which is connected through a connection terminal13to the first circuit board11which is housed in the top housing1includes only a first antenna part31. On the other hand, at the end22of the second circuit board12, a part18which includes a conductor is attached to be positioned right under the antenna3. The part18which includes a conductor may also be attached to the second circuit board12without extending the end22of the second circuit board12. Further, it is also possible to extend the end22of the second circuit board12and have that extension part attached to. The current EC which flows to the first circuit board11flows dispersed as the current ec to the second circuit board12due to this part18which includes a conductor.

FIG. 13is a partial cross-sectional view which illustrates a fifth embodiment of a lateral slide type mobile phone10of the present application. This is an embodiment which combines the antenna3of the first embodiment and the second circuit board12of the third embodiment. That is, if configuring the antenna3from the above-mentioned first antenna part31and second antenna part32and providing the end22of the second circuit board12with a board extension part17which is extended to a position right under the antenna3, the fifth embodiment is obtained. The current EC which flows to the first circuit board11flows dispersed as the current ec to the second circuit board12due to this second antenna part32and board extension part17.

FIG. 14is a partial cross-sectional view which illustrates a sixth embodiment of a lateral slide type mobile phone10of the present application. This is an embodiment which combines the antenna3of the second embodiment and the second circuit board12of the third embodiment. If configuring the antenna3from the above-mentioned first antenna part31, second antenna part32, and third antenna part33and providing the end22of the second circuit board12with a board extension part17which is extended to a position right under the antenna3, the sixth embodiment is obtained. The current EC which flows to the first circuit board11flows dispersed as the current ec to the second circuit board12due to this second antenna part32, third antenna part33, and board extension part17.

FIG. 15is a partial cross-sectional view which illustrates a seventh embodiment of a lateral slide type mobile phone10of the present application. This is an embodiment which combines the antenna3of the first embodiment and the second circuit board12of the fourth embodiment. That is, the antenna3includes the above-mentioned first antenna part31and second antenna part32. At the end22of the second circuit board12, the part18which includes a conductor is attached to be positioned right under the antenna3. The part18which includes a conductor may also be attached to the second circuit board12without extending the end22of the second circuit board12. Further, it is also possible to extend the end22of the second circuit board12and have that extension part attached to. The current EC which flows to the first circuit board11flows dispersed as the current ec to the second circuit board12due to this second antenna part32and part18which includes a conductor.

FIG. 16is a partial cross-sectional view which illustrates an eighth embodiment of the mobile communication device of the present application and is a partial cross-sectional view which illustrates the state of the antenna3of the second embodiment and the second circuit board12of the fourth embodiment combined. The antenna3includes the above-mentioned first antenna part31, second antenna part32, and third antenna part33. At the end22of the second circuit board12, the part18which includes a conductor is attached so as to be positioned right under the antenna3. The current EC which flows to the first circuit board11flows dispersed as the current ec to the second circuit board12due to this second antenna part32, third antenna part33, and part18which includes a conductor.

FIG. 17toFIG. 19are perspective views which view the specific shape of the antenna3of the first embodiment of the present application from three directions. The antenna3of the first embodiment is provided with a first antenna part31and with a second antenna part32which extends from the first antenna part31and is bent in perpendicular direction. The second antenna part32is further extended from the end of the first antenna part31and bent at its extension part along the edge of the first circuit board11.

FIG. 20is a perspective view which illustrates the state where the antenna3which is illustrated inFIG. 17toFIG. 19is attached to the end21of the first circuit board11. This corresponds to the configuration which is illustrated inFIG. 5.FIG. 21is a partial cross-sectional view which illustrates the state where the antenna3of the first embodiment of the present application is attached instead of the antenna3which is illustrated inFIG. 7. Further,FIG. 22is a partial cross-sectional view which illustrates the state where the antenna3of the first embodiment of the present application is attached instead of the antenna3which is illustrated inFIG. 8. Furthermore,FIG. 23is a partial cross-sectional view which illustrates the state where the antenna3of the first embodiment of the present application is attached instead of the antenna3which is illustrated inFIG. 6.

Further,FIG. 24is a perspective view which illustrates the second circuit board12as a whole when cutting the flexible cable15which connects the first circuit board11and second circuit board12which are illustrated inFIG. 20and which illustrates the state when attaching a display4to the first circuit board11.

FIG. 25toFIG. 27are perspective views which illustrate the structures of antennas of modified embodiments of the antenna3of the first embodiment of the present application which is illustrated inFIG. 17toFIG. 19. At the antenna3which is illustrated inFIG. 25, the second antenna part31is provided with a plurality of small through holes34. At the antenna3which is illustrated inFIG. 26, the second antenna part31is formed by mesh wire35. Furthermore, at the antenna3which is illustrated inFIG. 27, the second antenna part32is formed with a plurality of slits36and the second antenna board31is formed in a comb shape. These modified embodiments are for reducing the weight of the antenna3.

FIG. 28is a perspective view which illustrates the specific shape of the antenna3of the second embodiment of the present application. This figure illustrates the specific shape of the antenna3of the second embodiment as viewed from the same direction as the direction of the antenna3of the first embodiment which is illustrated inFIG. 19. Further,FIG. 29is a perspective view which illustrates one example of a modification of the antenna3of the second embodiment of the present application and is a view from the same direction as the antenna3of the first embodiment which is illustrated inFIG. 17. In this modification, the second antenna part32is provided with a large through hole37so as to reduce the weight of the antenna3.

FIG. 30is a perspective view which illustrates a configuration where the second circuit board12which is illustrated inFIG. 24is replaced by the second circuit board12of the third embodiment of the present application. In the third embodiment, the end22of the second circuit board12at the antenna3side is extended whereby a board extension part17is formed. The board extension part17is positioned right under the antenna3which is connected to the first circuit board11when the first circuit board11is superposed over the second circuit board12.

FIG. 31is a perspective view which illustrates the specific configuration of the second circuit board12of the fourth embodiment of the present application. In the fourth embodiment, at the end22of the second circuit board12at the antenna3side, a part18which includes a conductor, for example, a track ball18, is attached. The track ball18may be directly attached to the second circuit board12, but it is also possible to provide a board extension part17similar to the third embodiment and attach the ball to the board extension part17. The part18which includes a conductor is positioned right under the antenna3which is connected to the first circuit board11when the first circuit board11is superposed over the second circuit board12.

FIG. 32is a perspective view which illustrates a mobile communication device20of the second aspect according to the present application in which the first circuit board and the second circuit board are arranged in a single housing. The mobile communication device20of the second aspect is, for example, a straight-type mobile phone20.FIG. 33is a partial cross-sectional view which illustrates a conventional antenna structure in the straight-type mobile phone20. At the inside of a one-piece housing23of the conventional straight-type mobile phone20, a first circuit board11and a second circuit board12are provided in parallel. A thin strip antenna3which is provided with only the first antenna part31is connected to the end21of the first circuit board11by the connection terminal13.

In the present application, in the straight-type mobile phone20of the second aspect as well, the current EC which flows to the first circuit board11is dispersed and the dispersed current ec is made to flow to the second circuit board12.FIG. 34toFIG. 37are partial cross-sectional views which illustrate basic first to fourth embodiments of the present application in the second aspect. Here, illustration of the current EC which flows through the first circuit board11and the current ec which flows through the second circuit board12in the first to fourth embodiments of the second aspect is omitted. Further, illustration of the fifth to eight embodiments of combinations of the first to fourth embodiments such as illustrated fromFIG. 13toFIG. 16in the second aspect will also be omitted.

FIG. 34is a partial cross-sectional view which illustrates the shape of the antenna3in a first embodiment of the straight-type mobile phone20of the present application. In the first embodiment, the antenna3which is connected through the connection terminal13to the first circuit board11which is housed in the housing23includes the first antenna part31and the second antenna part32. The first antenna part31is provided laid along the end21of the first circuit board11in a direction parallel to the first circuit board11, while the second antenna part32is provided extending from the end of the first antenna part32and bent to the second circuit board12side. The current which flows to the first circuit board11flows dispersed to the second circuit board12due to this second antenna part32.

FIG. 35is a partial cross-sectional view which illustrates the shape of the antenna3in a second embodiment of the straight-type mobile phone20of the present application. In the second embodiment, the antenna3which is connected through the connection terminal13to the first circuit board11which is housed in the housing23includes the first antenna part31, second antenna part32, and third antenna part33. The first antenna part31is provided laid along the end21of the first circuit board11in a direction parallel to the first circuit board11, while the second antenna part32is provided extending from the end of the first antenna part32and bent to the second circuit board12side. Furthermore, the third antenna part33is provided extending from the end of the second antenna part32and bent at this extension part in a direction parallel to the second circuit board12. The current which flows to the first circuit board11flows dispersed to the second circuit board12due to this second antenna part32and third antenna part33.

FIG. 36is a partial cross-sectional view which illustrates the shape of the second circuit board12in a third embodiment of the lateral slide-type mobile phone10of the present application. In the third embodiment, the antenna3which is connected through the connection terminal13to the first circuit board11which is housed in the housing23includes only the first antenna part31. On the other hand, the end22of the second circuit board12is extended by the board extension part17to a position right under the antenna3. The current which flows through the first circuit board11flows dispersed to the second circuit board12due to this board extension part17.

FIG. 37is a partial cross-sectional view which illustrates the shape of the second circuit board12in a fourth embodiment of the straight type mobile phone20of the present application. In the fourth embodiment, the antenna3which is connected through the connection terminal13to the first circuit board11which is housed in the housing23includes only the first antenna part31. On the other hand, at the end22of the second circuit board12, a part18which includes a conductor is attached so as to be positioned right under the antenna3. The part18which includes a conductor may also be attached to the second circuit board12without extending from the end22of the second circuit board12. Further, the end22of the second circuit board12may also be extended and that extension part attached to. The current which flows to the first circuit board11flows dispersed to the second circuit board12due to the part18including this conductor.

In the mobile communication device of the first aspect and second aspect configured in the above way, if configuring the antenna like in the first embodiment, the amount of the effect received from the user body at the time of use of the mobile communication device becomes 20% or so smaller. Further, if configuring the antenna like in the second embodiment, the amount of the effect received from the user body at the time of use of the mobile communication device becomes 40% or so smaller. As a result, the gain of the antenna is improved 12.5% or so in the first embodiment and is improved 16.7% or so in the second embodiment.

Note that, as illustrated in the first and second embodiments of the present application, it may also be considered not to bend the end of the antenna3to the second circuit board side, but to increase the thickness of the antenna3itself and electromagnetically couple this to the second circuit board, but the antenna characteristics would end up deteriorating, so this is low in practicality.

According to the present application, it becomes possible to improve the antenna performance in a mobile communication device where an antenna is mounted inside the housing at the side close to the user body at the time of use.