Patent Publication Number: US-6903694-B2

Title: Antenna unit using helical hinge spring

Description:
This application claims priority to an application entitled “ANTENNA UNIT USING HELICAL HINGE SPRING”, filed in the Korean Industrial Property Office on Jan, 18, 2002 and assigned Serial No. 2002-2934, the contents of which are hereby incorporated by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an antenna unit of a portable terminal, and more particularly to an antenna unit using a helical hinge spring installed on the hinge module. 
   2. Description of the Related Art 
   Usually, a portable terminal refers to a portable unit for communicating with a counterpart via wireless communication with a base station. These portable terminals are divided into several types, e.g., bar-type terminals, flip-type terminals, folder-type terminals, flip up-type terminals, and folder-type terminals for being also used as a PDA, according to their shape. Further, the portable telephone terminals may be divided into telephone terminals for voice communication, telephone terminals for picture communication, telephone terminals for Internet communication, telephone terminals for Internet gaming, and telephone terminals for chatting, according to their function. Moreover, the portable telephone terminals may be divided into necklace types, wristlet types, and pocket-sized types, according to their wearing locations. 
   Each of the aforementioned individual portable terminals essentially comprises an antenna unit, a data input/output unit, and a data transmitting/receiving unit to facilitate communication with the counterpart. As the usually used data input unit, a keypad or a touch sensitive panel is employed. The keypad comprises an array of a plurality of keys for inputting data by a pressing action. The touch sensitive panel serves to input data by a touching action. Further, a display such as a LCD (Liquid Crystal Display) module is also commonly used as the data output unit. A microphone unit is used as the data transmitting unit and a speaker unit is used as the data receiving unit. 
   Portable terminals having multiple functionality and that are suitable for various multi-media environments are being spotlighted and popularized. 
   In order to transmit/receive radio waves, conventional portable terminals essentially comprises an antenna, a power-feeding portion, and an RF (Radio Frequency) unit. The conventional antennas of the portable terminal are divided into two types, i.e., an internal type and an external type. The internal type antenna is installed within a main housing of the portable terminal. The external type antenna protrudes from the main housing of the portable terminal and is exposed to the outside. As the conventional antenna, a helical antenna or a whip antenna is usually employed. Herein, the helical antenna serves as a main antenna and the whip antenna serves as an auxiliary antenna. 
   However, in case of using an internal type antenna installed on a designated area of a printed circuit board within the main housing of the portable terminal, the portable terminal requires an internal space for accommodating the internal type antenna, making it difficult to effectively utilize the limited space available within the main body of the portable terminal. That is, the portable terminal using the internal antenna has a drawback of increasing the size of the printed circuit board. 
   On the other hand, the external type antenna protrudes from the main body of the portable terminal, thereby limiting the external design of the portable terminal. Further, when the portable terminal falls to the ground due to the user&#39;s carelessness, the external type antenna is easily broken. Since the external antenna of the portable telephone terminal protrudes from the main body housing, this protruded external antenna of the portable terminal is easily damaged. 
   SUMMARY OF THE INVENTION 
   Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide an antenna unit using a hinge spring, thereby maintaining antenna characteristics and not requiring a further space for accommodating the antenna unit. 
   It is another object of the present invention to provide an antenna unit using a hinge spring, which satisfies a miniaturization trend. 
   It is another object of the present invention to provide an antenna unit using a hinge spring, which can be used as an auxiliary antenna. 
   In accordance with one aspect of the present invention, the above and other objects can be accomplished by the provision of an antenna unit using a helical hinge spring which is used in a portable terminal including (A) a main housing, (B) a sub housing, and (C) a hinge module rotatably opening and closing the sub housing from and into the main housing and including a hinge shaft having one end fixedly attached to the main housing and the other end positioned within the sub housing and serving to interconnect the main housing and the sub housing, a hinge cam being slid by the hinge shaft and moving forward and backward, the helical hinge spring for providing a force for closely adhering the hinge shaft to the hinge cam, and a hinge housing for accommodating the hinge shaft, the hinge cam, and the helical hinge spring, the antenna unit comprising: (a) the helical hinge spring disposed in a direction of a hinge axis and serving as a helical antenna; and (b) a conductive member including a contact portion disposed between the helical hinge spring and the hinge cam and closely adhered to the hinge spring, and a center portion extending from a center of the contact portion in the direction of the hinge axis and passing through the hinge cam and the hinge shaft. 
   In accordance with another aspect of the present invention, there is provided to an antenna unit using a helical hinge spring which is used in a portable terminal including (A) a main housing, (B) a sub housing, and (C) a hinge receptor rotatably opening and closing the sub housing from and into the main housing and including a hinge shaft having one end fixedly attached to the main housing and the other end positioned within the sub housing and serving to interconnect the main housing and the sub housing, a hinge cam being slid by the hinge shaft and moving forward and backward, and the helical hinge spring for providing a force for closely adhering the hinge shaft to the hinge cam, the antenna unit comprising: (a) the helical hinge spring disposed in a direction of a hinge axis and serving as a helical antenna; and (b) a conductive member including a contact portion closely adhered to the helical hinge spring, and a center portion extending from a center of the contact portion in the direction of the hinge axis and passing through the hinge spring, the hinge cam and the hinge shaft. 
   In accordance with still another aspect of the present invention, there is provided to a hinge apparatus of a portable terminal including a hinge housing, a hinge shaft disposed within the hinge housing, a hinge cam disposed within the hinge housing and being slid by the hinge shaft, a helical hinge spring disposed in a direction of the hinge housing, and serving to closely adhere the hinge shaft to the hinge cam and simultaneously serving as a helical antenna; and a conductive member including a contact portion disposed between the helical hinge spring and the hinge cam and closely adhered to the helical hinge spring, and a center portion extending from a center of the contact portion in the direction of the hinge axis and passing through the hinge cam and the hinge shaft. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
       FIG. 1  is a perspective view of a portable terminal in which a sub housing is closed; 
       FIG. 2  is a perspective view of the portable terminal in which the sub housing is open; 
       FIG. 3  is a partial cut-away plan view of the portable terminal in which the sub housing is open, showing in cut-away an antenna unit using a helical hinge spring in accordance with the first preferred embodiment of the present invention; 
       FIG. 4  is a partially exploded plan view of the antenna unit using the helical hinge spring in accordance with the first embodiment of the present invention; 
       FIG. 5  is a cross-sectional view of the antenna unit of  FIG. 4 ; 
       FIG. 6  is a partially exploded plan view of an antenna unit using a helical hinge spring in accordance with a second preferred embodiment of the present invention; 
       FIG. 7  is a cross-sectional view of the antenna unit of  FIG. 6 ; 
       FIG. 8   a  is a graph showing a radiation pattern illustrating the antenna characteristics of a conventional antenna unit using a helical antenna at Korean PCS band (1,750˜1,870 MHz) in an open status of a sub housing; 
       FIG. 8   b  is a graph showing a radiation pattern illustrating the antenna characteristics of the conventional antenna unit using the helical antenna at Korean PCS band (1,750˜1,870 MHz) in a closed status of the sub housing; 
       FIG. 9   a  is a graph showing a radiation pattern illustrating the antenna characteristics of the antenna unit using the helical hinge spring at Korean PCS band (1,750˜1,870 MHz) in an open status of a sub housing in accordance with the first embodiment of the present invention; 
       FIG. 9   b  is a graph showing a radiation pattern illustrating the antenna characteristics of the antenna unit using the helical hinge spring at Korean PCS band (1,750˜1,870 MHz) in a closed status of the sub housing in accordance with the first embodiment of the present invention; 
       FIG. 10   a  is a graph showing a radiation pattern illustrating the antenna characteristics of a conventional chip type antenna at BT (Blue Tooth) band (2,400˜2,483 MHz) in an open status of a sub housing; 
       FIG. 10   b  is a graph showing a radiation pattern illustrating the antenna characteristics of the conventional chip type antenna at BT (Blue Tooth) band (2,400˜2,483 MHz) in a closed status of the sub housing; 
       FIG. 11   a  is a graph showing a radiation pattern illustrating the antenna characteristics of the antenna unit using the helical hinge spring at BT (Blue Tooth) band (2,400˜2,483 MHz) in an open status of a sub housing in accordance with the first embodiment of the present invention; and 
       FIG. 11   b  is a graph showing a radiation pattern illustrating the antenna characteristics of the antenna unit using the helical hinge spring at BT (Blue Tooth) band (2,400˜2,483 MHz) in a closed status of the sub housing in accordance with the first embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Now, preferred embodiments of the present invention will be described in detail with reference to the annexed drawings. In the drawings, the same or similar elements are denoted by the same reference numerals even though they are depicted in different drawings. In the following description, a detailed description of known functions and configurations is omitted to avoid making the subject matter of the present invention unclear. 
     FIG. 1  is a perspective view of a portable terminal in which a sub housing is closed, and  FIG. 2  is a perspective view of the portable terminal in which the sub housing is open. The portable terminal of  FIGS. 1 and 2  also comprises an antenna unit (shown in  FIG. 3 ) using a helical hinge spring in accordance with the first preferred embodiment of the present invention. The portable terminal comprises a main housing  10 , a sub housing  20 , and a hinge unit. The hinge unit rotatably connects the sub housing  20  to the main housing  10 , thereby opening and closing the sub housing  20  from and into the main housing  10 . That is, the sub housing  20  rotatably moves on a rotation axis A within a designated angle. The main housing  10  comprises a key array consisting of a plurality of keys  112 , and a microphone unit  114 . The sub housing  20  comprises a speaker unit  212  and a LCD  214 . 
   The main housing  10  includes two side hinge arms  110 . One side hinge arm  110  is symmetrically opposite to the other side hinge arm  110 . The sub housing  20  includes a center hinge arm  201 . The center hinge arm  201  of the sub housing  20  is held between the two side hinge arms  110  of the main housing  10  by the hinge unit. 
   As shown in  FIG. 3 , a hinge module  30  applied to the portable terminal functions first to rotatably connect the sub housing  20  to the main housing  10  and secondarily to provide a force for closing the sub housing  20  within a first range of designated angles (0°˜45°), provide a force for opening the sub housing  20  in a second range of more than the first range of designated angles (45°˜140°), and provide a force for stopping the motion of the sub housing  20  at another third designated angle (140°). That is, the hinge module  30  of the portable terminal provides a user with a force for easily opening and closing the sub housing  20  from and into the main housing  10 . Therefore, the hinge module  30  essentially comprises a hinge shaft  302 , a hinge cam  303 , and a helical hinge spring  305 . Further, a hinge housing  301  may be used to separately assemble the hinge shaft  302 , the hinge cam  303 , and the helical hinge spring  305  of the hinge module  30 . 
   The hinge module  30  of the first preferred embodiment of the present invention, particularly the helical hinge spring  305  is used as the antenna unit.  FIG. 3  shows the antenna unit using the helical hinge spring  305  of the hinge module  30  in accordance with the first embodiment of the present invention. 
   As shown in  FIG. 3 , the antenna unit of the first embodiment of the present invention comprises the hinge module  30 , more particularly the helical hinge spring  305  accommodated within the hinge housing  301 , a conductive member  304 , and a plate spring  32  located within internal space  110   a  of side hinge arm  110 . The conductive member  304  is accommodated within the hinge housing  301  so as to electrically connect the helical hinge spring  305  to a power-feeding portion (not shown). The plate spring  32  is closely adhered to the conductive member  304 , thereby electrically connecting the conductive member  304  to the power-feeding portion. 
     FIG. 4  is a partially exploded plan view of the antenna unit using the helical hinge spring in accordance with the first preferred embodiment of the present invention, and  FIG. 5  is a cross-sectional view of the antenna unit of FIG.  4 . Hereinafter, with reference to  FIGS. 4 and 5 , the antenna unit of the first preferred embodiment of the present invention is described in detail. 
   As shown in  FIGS. 4 and 5 , the antenna unit of the first embodiment of the present invention utilizes the hinge module  30 . In order to supply a force for opening and closing the sub housing, the hinge module comprises the hinge housing  301 , the hinge shaft  302 , the hinge cam  303 , and the helical hinge spring  305 . The antenna unit of the first embodiment of the present invention is embodied using the helical hinge spring  305  installed on the hinge module and the conductive member  304  separate from the helical hinge spring  305 . 
   The hinge housing  301  is installed on the center hinge arm  201  of the sub housing  20 , and accommodates the hinge shaft  302 , the hinge cam  303 , the conductive member  304 , and the helical hinge spring  305 . One end  302   a  of the hinge shaft  302  is engaged with the side hinge arm  110  of the main housing  10  and the other end  302   b  of the hinge shaft  302  is a convex portion. Further, a through hole  302   c  is formed in the hinge shaft  302  along the hinge axis. The hinge shaft  302  is fixedly attached to the side hinge arm  110 . Therefore, as the sub housing  20  is opened and closed from and into the main housing  10 , the hinge cam  303  slides due to its engagement with convex portion  302   b  of hinge shaft  302 . 
   The hinge cam  303  includes convex portion  303   a  and a concave portion  303   b . A protrusion  303   d  is formed on the outer circumference of the hinge cam  303 ; the protrusion  303   d  guides the hinge cam  303  forward and backward within the hinge housing  301 . The hinge cam  303  is slid by the hinge shaft  302 , and thereby moves forward and backward along the length direction of the hinge housing  301 . A through hole  303   c  is formed in the hinge cam  303  along the hinge axis. 
   The conductive member  304  includes a contact portion  304   a  disposed between the hinge cam  303  and the helical hinge spring  305  and being in contact with one end  305   a  of the helical hinge spring  305 , and a center portion  304   b  being inserted into the through hole  303   c  of the hinge cam  303  and the through hole  302   c  of the hinge shaft  302 . A terminal  304   c  of the center portion  304   b  of the conductive member  304  has a designated length so as to protrude from the surface of the hinge shaft  302 . The diameter of the center portion  304   b  of the conductive member  304  is smaller than that of the through holes  302   c  and  303   c . Therefore, the conductive member  304  is not influenced by the straight-line motion of the hinge shaft  302  or the hinge cam  303 . 
   The helical hinge spring  305  is disposed between the hinge housing  301  and the conductive member  304 . One end  305   a  of the helical hinge spring  305  is always in contact with the contact portion  304   a  of the conductive member  304 , thereby functioning to closely adhere the hinge shaft  302  to the hinge cam  303 . 
   The plate spring  32  is made of a conductive material with elasticity. The plate spring  32  includes two free terminals, i.e., a first free terminal  321  and a second free terminal  322 . The first free terminal  321  of the plate spring  32  is bent to be connected to the terminal  304   c  of the center portion  304   b  of the conductive member  304 , and the second free terminal  322  of the plate spring  32  is connected to the power-feeding portion of a main printed circuit board (not shown). Herein, the first free terminal  321  of the plate spring  32  is closely adhered to the terminal  304   c  of the conductive member  304  by an elastic force of the plate spring  32 . 
   When the sub housing is opened and closed from and into the main housing, the hinge shaft  302  is bound by one of the side hinge arms  110 , and the hinge cam  303  moves forward and backward by the hinge shaft  302 . Then, the helical hinge spring  305  is compressed and then extends. Further, the conductive member  304  is maintained in close adherence with the hinge spring  305 . Therefore, the helical hinge spring  305  is always electrically connected to the plate spring  32  by the conductive member  304 , and is connected to the power-feeding portion via the plate spring  32 . 
     FIG. 6  is a partially exploded plan view of an antenna unit using a helical hinge spring in accordance with a second preferred embodiment of the present invention, and  FIG. 7  is a cross-sectional view of the antenna unit of FIG.  6 . Hereinafter, with reference to  FIGS. 6 and 7 , the antenna unit using the helical hinge spring  403  of the second preferred embodiment of the present invention is described in detail. As shown in  FIGS. 6 and 7 , the antenna unit using the helical hinge spring  403  of the second embodiment of the present invention utilizes a hinge module  40 . In order to supply a force for opening and closing the sub housing, the hinge module  40  serving as the hinge means of the portable terminal comprises a hinge shaft  401 , a hinge cam  402 , and the helical hinge spring  403 . The antenna unit of the second embodiment of the present invention is embodied using the helical hinge spring  403  installed on the hinge module  40  and a conductive member  404 . 
   The hinge shaft  401 , the hinge cam  402 , the conductive member  404 , and the helical hinge spring  403  are accommodated within a hinge receptor  405  installed within the center hinge arm  201  of the sub housing  20 . One end  401   a  of the hinge shaft  401  protrudes from the hinge receptor and the other end  401   b  of the hinge shaft  401  is a convex portion. A through hole  401   c  is formed in the hinge shaft  401  along the hinge axis. 
   The hinge cam  402  includes a convex portion  402   a  and a concave portion  402   b . A protrusion  402   c  is formed on the outer circumference of the hinge cam  402 , thereby moving the hinge cam  402  forward and backward within the hinge receptor. The hinge cam  402  is slid by the hinge shaft  401 , thereby moving forward and backward along the length direction of the hinge receptor  405 . A through hole  402   d  is formed in the hinge cam  402  along the hinge axis. 
   The conductive member  404  includes a contact portion  404   a  disposed between one end  403   b  of the helical hinge spring  403  and a separation wall of the hinge receptor  405  and being in contact with the end  403   b  of the helical hinge spring  403 , and a center portion  404   b  disposed within the helical hinge spring  403  and inserted into the through hole  402   d  of the hinge cam  402  and the through hole  401   c  of the hinge shaft  401 . A terminal  404   c  of the center portion  404   b  of the conductive terminal  404  has a designated length so as to protrude from the surface of the hinge shaft  401 . The diameter of the center portion  404   b  of the conductive member  404  is smaller than that of the through holes  401   c  and  402   d . Therefore, the conductive member  404  is not influenced by the straight-line motion of the hinge shaft  401  and the hinge cam  402 . 
   The helical hinge spring  403  is disposed between the hinge shaft  401  and the conductive member  404 . One end  403   b  of the helical hinge spring  403  is always in contact with the contact portion  404   a  of the conductive member  404 , thereby functioning to closely adhere the hinge shaft  401  to the hinge cam  402 . 
   A plate spring  42  is made of a conductive material. The plate spring  42  includes two free terminals, i.e., a first free terminal  421  and a second free terminal  422 . The first free terminal  421  of the plate spring  42  is bent to be connected to the terminal  404   c  of the center portion  404   b  of the conductive member  404 , and the second free terminal  422  of the plate spring  42  is connected to the power-feeding portion (not shown). Herein, the first free terminal  421  of the plate spring  42  is closely adhered to the terminal  404   c  of the conductive member  404  by an elastic force of the plate spring  42 . 
   When the sub housing is opened and closed from and into the main housing, the hinge shaft  401  is bound by one of the side hinge arms  110 , and the hinge cam  402  moves forward and backward over the convex portion  401   b  of the hinge shaft  401 . Then, the helical hinge spring  403  is compressed and expanded. Further, the hinge spring  403  is maintained to be in close adherence with the contact portion  404   a  of the conductive member  404 . Therefore, the helical hinge spring  403  is always electrically connected to the plate spring  42  by the conductive member  404 , and is electrically connected to the power-feeding portion via the plate spring  42 . 
   Hereinafter, with reference to  FIGS. 8   a  to  11   b , the antenna characteristics of the antenna unit using the helical hinge spring in accordance with the first embodiment of the present invention is described in comparison with the conventional antenna unit. 
     FIG. 8   a  is a graph showing a radiation pattern illustrating the antenna characteristics of a conventional antenna unit using a helical antenna at Korean PCS band (1,750˜1,870 MHz) in an open status of a sub housing, and  FIG. 8   b  is a graph showing a radiation pattern illustrating the antenna characteristics of the conventional antenna unit using the helical antenna at Korean PCS band (1,750˜1,870 MHz) in a closed status of the sub housing. 
     FIG. 9   a  is a graph showing a radiation pattern illustrating the antenna characteristics of the antenna unit using the helical hinge spring at Korean PCS band (1,750˜1,870 MHz) in an open status of a sub housing in accordance with the first embodiment of the present invention, and  FIG. 9   b  is a graph showing a radiation pattern illustrating the antenna characteristics of the antenna unit using the helical hinge spring at Korean PCS band (1,750˜1,870 MHz) in a closed status of the sub housing in accordance with the first embodiment of the present invention. 
   As shown in  FIGS. 8   a  to  9   b , a peak gain and a gain of a +90 direction of the antenna unit using the helical hinge spring of the first embodiment of the present invention in the closed status of the sub housing are a little lower than those of the conventional antenna unit. However, those gains of the antenna unit using the helical hinge spring of the first embodiment of the present invention in the open status of the sub housing are higher than those of the conventional antenna unit. 
     FIG. 10   a  is a graph showing a radiation pattern illustrating the antenna characteristics of the conventional chip type antenna at BT (Blue Tooth) band (2,400˜2,483 MHz) in an open status of a sub housing, and  FIG. 10   b  is a graph showing a radiation pattern illustrating the antenna characteristics of the conventional chip type antenna at BT (Blue Tooth) band (2,400˜2,483 MHz) in a closed status of the sub housing. 
     FIG. 11   a  is a graph showing a radiation pattern illustrating the antenna characteristics of the antenna unit using the helical hinge spring at BT (Blue Tooth) band (2,400˜2,483 MHz) in an open status of a sub housing in accordance with the first embodiment of the present invention, and  FIG. 11   b  is a graph showing a radiation pattern illustrating the antenna characteristics of the antenna unit using the helical hinge spring at BT (Blue Tooth) band (2,400˜2,483 MHz) in a closed status of the sub housing in accordance with the first embodiment of the present invention. 
   As shown in  FIGS. 10   a  to  11   b , the peak gain and an average gain of the antenna unit using the helical hinge spring of the first embodiment of the present invention in the open and closed status of the sub housing are higher than those of the conventional antenna unit. The helical hinge spring of the present invention has a diameter of approximately 4.3 mm and a length of approximately 9.5 mm. Therefore, if the helical hinge spring has a greater diameter and length using a bigger hinge module, an antenna unit with further improved antenna characteristics can be obtained. 
   Additionally, the helical hinge spring of the present invention is designed to satisfy the antenna characteristics by adjusting the diameter and the length of the helical hinge spring, thereby being used as various kinds of antennas. 
   Consequently, the antenna unit using helical hinge spring of the present invention can be substituted for the conventional antenna at Korean PCS band or BT (Blue Tooth) band. Therefore, the antenna unit of the present invention satisfies the miniaturization of the main body of the portable terminal, improves a portable function of the portable terminal, and allows more flexible designing of an external appearance of the portable terminal. 
   For example, as the hinge module is enlarged by the increase of the size of the main body of the terminal, the length and/or diameter of the helical hinge spring may also be increased, thereby improving the antenna gain by the helical hinge spring. 
   As apparent from the above description, according to the present invention, the antenna unit is obtained using a hinge module, thereby allowing more flexible designing of an external appearance of the portable terminal using the antenna and reducing the production cost of the antenna. Further, the present invention does not require an internal space for accommodating an additional antenna, thereby maximizing space utilization and satisfying a lightweight trend. Moreover, the antenna unit of the present invention can be used as a supplementary antenna of a dual band terminal operated at a combined band of PCS, CDMA, AMPS, GSM, GPS, BT (blue tooth), and so on, and as a diversity antenna for increasing the data speed of a terminal requiring a super high-speed data communication such as a HDR. 
   Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.