Patent Publication Number: US-11395418-B2

Title: Tuner module and receiving device

Description:
TECHNICAL FIELD 
     The present technology relates to a tuner module and a receiving device used for television broadcasting (terrestrial broadcasting, satellite broadcasting, cable television, etc.) reception. 
     BACKGROUND ART 
     Tuner modules each have a circuit board on which a circuit portion constituting at least part of a tuner is mounted, a metal shield case (referred to as a tuner case, as appropriate) housing the circuit board, and an antenna-signal input connector attached to the tuner case. One described in PTL 1 is proposed as one example of such tuner modules. 
     The tuner module described in PTL 1 has a configuration in which a ground terminal integrated with a tuner case is electrically connected with a circuit board via solder. The tuner module described in PTL 1 is to solve a problem that since the ground terminal, the circuit board, and the solder have mutually different thermal expansion coefficients in the configuration, the solder cracks, and the property in terms of contact between the ground terminal and the circuit board deteriorates. That is, since it is difficult, in terms of processing, to provide a penetrating hole for a through hole at an outer circumference section of the circuit board, the structure of the ground terminal is often used on the outer circumference of the tuner case. 
     CITATION LIST 
     Patent Literature 
     
         
         [PTL 1] 
       
    
     JP 2010-021494A 
     SUMMARY 
     Technical Problem 
     The configuration described in PTL 1 has a drawback in terms of insufficient strengths of joints since the ground terminal which is soldered does not penetrate a through hole of the circuit board. In addition, complicated processing methods such as coining have been required for maintaining the strengths of solder-joint points, and giving the solder-joint points flexibility against temperature. However, such necessitates different detail designing for different models depending on the overall shapes of tuners, the positions of ground terminals and the like, and becomes a cause of an increase of man-hours for designing. 
     Accordingly, an object of the present technology is to provide a tuner module that makes it possible to sufficiently ensure the strengths of joints between a ground terminal and a circuit board, to simplify processing methods, and to prevent an increase of man-hours for designing. 
     Solution to Problem 
     The present technology relates to a tuner module including an input connector, a tuner case, a circuit board, and an auxiliary piece. The auxiliary piece contacts a surface of the tuner case and is fixed to the surface of the tuner case, and part of the auxiliary piece is connected as a ground potential near a contact of a core wire of the input connector with the circuit board. In addition, the present technology relates to a receiving device having the tuner module. 
     Advantageous Effects of Invention 
     According to at least one embodiment, a direct current and a high-frequency resistance between grounds of an input connector, a nearby tuner case, and a circuit board can be made very small, and also joints between the tuner case and the circuit board can be made strong. Note that the effects described here are not necessarily the only effects, and effects that can be attained may include any effect described in the present technology and an effect which is different in kind from those effects. In addition, the effects illustrated as examples in the following explanation should not be interpreted as limitations on the content of the present technology. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of a first embodiment of the present technology. 
         FIG. 2  is a perspective view of the first embodiment of the present technology. 
         FIG. 3  is a perspective view of the first embodiment of the present technology. 
         FIG. 4  is a perspective view of the first embodiment of the present technology. 
         FIG. 5  includes  FIG. 5A  to  FIG. 5D  which are schematic diagrams used for explanation of conventional tuner-module assembling steps. 
         FIG. 6  includes  FIG. 6A  to  FIG. 6D  which are schematic diagrams used for explanation of the present technology. 
         FIG. 7  includes  FIG. 7A  and  FIG. 7B  which are schematic diagrams used for explanation of the present technology. 
         FIG. 8  is a perspective view of a second embodiment of the present technology. 
         FIG. 9  is a perspective view of the second embodiment of the present technology. 
         FIG. 10  is a perspective view of the second embodiment of the present technology. 
         FIG. 11  is a perspective view of a third embodiment of the present technology. 
         FIG. 12  is a perspective view of the third embodiment of the present technology. 
         FIG. 13  is a perspective view of the third embodiment of the present technology. 
         FIG. 14  is a schematic diagram illustrating a configuration for measuring the effects of the present technology. 
         FIG. 15  is a perspective view of a modification of the present technology. 
         FIG. 16  is a perspective view of the modification of the present technology. 
         FIG. 17  is a perspective view of the modification of the present technology. 
         FIG. 18  is a perspective view of the modification of the present technology. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments explained below are suitable specific examples of the present technology, and given various technologically preferable limitations. However, the scope of the present technology is not limited by the embodiments unless there are descriptions that limit the present technology in particular manners in the following explanation. 
     Note that the explanation of the present technology is given in accordance with the following order.
     &lt;1. First Embodiment of Present Technology&gt;   &lt;2. Second Embodiment of Present Technology&gt;   &lt;3. Third Embodiment of Present Technology&gt;   &lt;4. Application Example&gt;   &lt;5. Modification&gt;   

     1. First Embodiment of Present Technology 
     Hereinafter, a first embodiment of a tuner module according to the present technology is explained with reference to the drawings.  FIG. 1  is a perspective view illustrating a configuration example of the tuner module according to the first embodiment of the present technology.  FIG. 2  is a perspective view of a state where a circuit board is removed.  FIG. 3  is a perspective view of a state where the circuit board and an auxiliary piece are removed.  FIG. 4  is a perspective view of a state where the circuit board and the auxiliary piece are removed, and the tuner module is turned upside down as compared to the one illustrated in  FIG. 3 . 
     The tuner module includes a tuner case  11 , a circuit board  12 , an input connector  13 , and an auxiliary piece  14 . On one surface or both surfaces of the circuit board  12 , circuit components that constitute at least part of the tuner module are mounted. The tuner case  11  is a metallic case that functions as a shield case. Note that a lid (not illustrated) may cover part of or the entire surface of the circuit board  12 . The lid includes a material similar to the material of the tuner case  11 . 
     The tuner case  11  has a box shape including: a rectangular bottom-surface plate  11   a ; and a front-surface plate  11   b,  a back-surface plate  11   c , a side-surface plate  11   d , and a side-surface plate  11   e  that are raised from the front, back, left, and right edges of the bottom-surface plate  11   a , respectively. The tuner case  11  has one open surface. In addition, hole sections  11   g  and  11   h  are screw holes for fixing the tuner module to the housing of a television receiver, for example. The circuit board  12  is attached so as to cover the open surface of the tuner case  11 . An external conductor of the input connector  13  includes a metal such as iron, brass, or zinc. As one example, a base section of the external conductor of the input connector  13  is attached to the front-surface plate  11   b  of the tuner case  11  by non-screwing mechanical joining, screwing or the like. 
     The input connector  13  is a coaxial connector used for supplying an output of an antenna to a tuner, for example, and is an IEC (International Electrotechnical Commission) connector, for example. It should be noted, however, that the input connector  13  may have another configuration, and may be an F connector, for example. One type of F connectors is connected to one end of a coaxial cable, and is called an F connector plug or the like. Another type of F connectors is an F connector that receives the center conductor (hereinafter, referred to as the core wire) of a coaxial cable projecting from an F connector plug, and is called an F connector receptacle or the like. 
     The core wire of the coaxial cable inserted into the input connector  13  is pinched by two internal spring contact points (pinching pieces). The spring contact points constitute at least part of a center electrode, and a terminal section  13   a  connected with the center electrode is introduced from a rear section of the input connector  13  into the tuner case  11  through a hole formed through the front-surface plate  11   b  of the tuner case  11  (see  FIG. 3 ). 
     A plurality of leg portions  21   1 ,  21   2 ,  21   3 , . . . , and  21   7  (in a case that it is not necessary to distinguish between these leg portions, these are referred to as leg portions  21 ) projects upward from end surfaces of the side-surface plates of the tuner case  11 . The leg portions  21  may penetrate holes formed through the circuit board  12 . The inner walls of the penetrating holes have through-hole structures plated with copper foils on the circuit board  12 , are connected with a ground terminal, and make the tuner case  11  serve as a uniform ground potential. In such a manner, joints can be formed around the entire circumferences of the through-hole holes of the circuit board  12  in which the leg portions  21  of the tuner case  11  are inscribed, and the mechanical strengths of the joints can be ensured. Note that all the leg portions projecting upward from the tuner case  11  are preferably joined with the holes formed through the circuit board  12 . 
     The terminal section  13   a  of the input connector  13  is bent upward at an intermediate portion thereof, and the bent portion serves as a leg portion  31 . The leg portion  31  may penetrate a hole formed through the circuit board  12 . The hole has a configuration of a through hole, and serves as a signal terminal on the circuit board  12 . 
     The auxiliary piece  14  is formed by bending a metal plate of a material similar to the material of the tuner case  11  into an L-shape, and has a base section  14   a  and a raised section  14   b . Center portions of the base section  14   a  and the raised section  14   b  are clipped to form an opening  14   c . The base section  14   a  of the auxiliary piece  14  is mechanically and electrically connected with the bottom-surface plate  11   a  of the tuner case  11 . Note that both the base section  14   a  and the raised section  14   b  may be mechanically and electrically connected with the tuner case  11 . The opening  14   c  is formed at a position similar to the position of the hole of the front-surface plate  11   b , and the terminal section  13   a  is introduced into the tuner case  11  through the hole and the opening  14   c . Methods that can be used for connection between the tuner case  11  and the auxiliary piece  14  include screwing, non-screwing mechanical joining, welding, soldering and the like. 
     The terminal section  13   a  is connected with the core wire of the coaxial cable connected to the input connector  13 , and for suppression of radio waves radiated from the terminal section  13   a , the length of the terminal section  13   a  is preferably short. On the other hand, since the leg portion  31  at the tip of the terminal section  13   a  may penetrate a through hole formed through the circuit board  12 , it becomes difficult to form the through hole at an end section of the circuit board  12  if the length of the terminal section  13   a  is made short. Accordingly, the length of the terminal section  13   a  is made short only to the extent that the through hole can be formed at the end section of the circuit board  12 . 
     Two leg portions  32  and  33  project parallel to each other inward from an upper section of the opening  14   c  of the raised section  14   b  of the auxiliary piece  14 . The leg portions  32  and  33  have approximately similar shapes which are bent upward at intermediate portions thereof. As illustrated in  FIG. 2 , the leg portions  32  and  33  are arranged to be positioned near both sides of the leg portion  31  of the terminal section  13   a . Accordingly, in a case that the leg portions  31 ,  32 , and  33  are connected to the circuit board  12 , the connection locations on the circuit board  12  may be positioned relatively close to each other. Thereby, occurrence of unnecessary radiation can be suppressed. 
     Since the leg portions  32  and  33  are connected with the tuner case  11 , the leg portions  32  and  33  serve as ground terminals. In order to provide such ground terminals, in a possible case, the auxiliary piece  14  may not be used, but by sheet metal working, for example, an external conductor of the input connector  13  may be cut, and the cut portions may be raised. The method leads to more significant deterioration of the strength of the input connector  13 , and there is a fear that when a load is applied to the input connector  13  by a coaxial cable connected to the input connector  13  at the time of actual use, the input connector  13  may be damaged. In addition, since a hole through which the core wire of the input connector  13  penetrates is provided, the leg portions are undesirably located closer to the input connector  13 , it becomes necessary to form holes, through which the leg portions are to be inserted, near an end section of the circuit board  12 , and there is a fear that the circuit board  12  may be damaged. Furthermore, the method of forming the leg portions by processing of cutting the tuner case  11  itself and raising the cut portions necessitates forming holes through the tuner case  11 , and gives rise to a problem that radiation from the holes is caused. 
     In order to avoid such problems, the auxiliary piece  14  is used. The auxiliary piece  14  assists connection between the tuner case  11  and the circuit board  12  that serve as a ground potential. The base section  14   a  of the auxiliary piece  14  is in surface-contact with the bottom-surface plate  11   a  of the tuner case  11 , thereby realizing a low contact resistance. In order to surely realize the surface-contact, as illustrated in  FIG. 4 , a plurality of protrusions  22   a ,  22   b ,  22   c , and  22   d  projecting from the base section  14   a  is formed, and holes  23   a ,  23   b ,  23   c , and  23   d  are formed at positions on the bottom-surface plate  11   a  that correspond to the protrusions  22   a  to  22   d . The protrusions  22   a  to  22   d  fit to the holes  23   a  to  23   d , thereby making it possible to surely realize the surface-contact. 
     In the first embodiment of the present technology mentioned above, all the ground connecting sections between the tuner case  11  and the circuit board  12  can be soldered connections around the entire circumferences of the through-hole hole sections. Accordingly, solder joints in which a direct current and a high-frequency resistance between grounds of the input connector, the nearby tuner case, and the circuit board can be made very small can be realized, and strong connections can be established. In addition, the intervals between the inner walls of the through holes and the inserted leg portions of the tuner case  11  are very narrow, and solder melted in a reflow oven experiences capillary action, and is drawn into the intervals, thereby making it possible to realize strong joints simply and conveniently. 
     For reference, conventional tuner-assembling steps are explained. A semifinished product of a tuner on which surface mount components are mounted on a circuit board is created. Typically, after solder before being melted is printed on the circuit board, the surface mount components are mounted in such a manner that the surface mount components come into contact with the solder printed by a robot machine having nozzles that suctionally attract the surface mount components, and the solder is melted by first heating by the reflow oven and joined with the surface mount components. Thereafter, a tuner case of the tuner is inserted into a slit section provided to the circuit board, and is joined by second heating by the reflow oven. The solder printing described above is a typical construction method (screen printing) of performing printing by using an aluminum screen of approximately 0.1 mm, and can fix many electronic components onto the circuit board while ensuring conduction therebetween. 
       FIG. 5  is for explaining the second reflow process. First, as illustrated in  FIG. 5A , a circuit board  101  is inverted before insertion of a tuner case, and on a side opposite to surface mount components  102 , solder  105  pushed into nozzles  104  by a laterally-sliding squeegee  103  is applied onto the board  101  in accordance with the principle of what is called mimeograph printing (collective application of solder). 
     Next, as illustrated in  FIG. 5B , while being careful not to allow the solder  105  before being melted to scatter or drip, the circuit board  101  is inverted again (board inversion). The reference signs  106   a  and  106   b  indicate copper foils. Then, as illustrated in  FIG. 5C , a mechanical component  107  such as a tuner case is mounted, and as illustrated in  FIG. 5D , the mechanical component  107  is joined by second reflowing. 
     In the conventional tuner manufacturing steps, the nozzles  104  need to be designed and manufactured as dedicated facilities optimized for individual tuners, and care is also required regarding the viscosity and granularity of the solder  105 , before being cured, to be applied by being caused to pass through the nozzles  104 . In addition, since heating by the reflow oven is performed at least twice during the steps, care is also required regarding heat stress on the surface mount components  102 . These issues make it necessary to perform inspections regarding the degree of completion by performing inspection experiments after trial manufacture, trial manufacture tests, tests for checking the reliability, and the like, and place a significant burden in terms of know-how, technology, costs, and time. 
     On the other hand, according to the present technology, the method of applying solder to fill the through-hole holes can be performed by printing on a surface where the surface mount components  102  are mounted by application of a screen. Accordingly, it is possible to make the nozzles  104  unnecessary, and the problems mentioned above can be solved. 
     In the first embodiment of the present technology mentioned above, the portion near the input connector  13  serves as a portion where conversion is performed such that what is called high-frequency signals, such as UHF-band signals or IF signals for satellite broadcasting, flowing through a coaxial line is made to flow through a planar circuit on the circuit board  12 . At such a portion, the change in the form of transmission paths, that is, release from a closed circuit in the coaxial line onto the board makes it more likely that the impedance of the high-frequency signals changes significantly. In view of this, for the characteristics impedance of 75Ω of typical coaxial lines, for the purpose of making the ground potentials of the points of conversion equal at the time of designing such that one line width of a double-sided board having a ground layer forms a 75-Ω microstrip line, the leg portions  32  and  33  are provided. 
     In the first embodiment of the present technology, high-frequency signals are supplied to a signal processing section (referred to as a planar circuit) on the circuit board  12  through the coaxial cable and the input connector  13 . That is, signals are transmitted from the coaxial cable to the planar circuit. The point is examined. 
     As illustrated in  FIG. 6 , a coaxial cable has a center conductor (core wire)  51  and an external conductor  53  that covers the center conductor  51  with a dielectric  52  being interposed therebetween. The circumference of the external conductor  53  is covered by a protection cover (not illustrated). A current flows inside the center conductor  51  and the external conductor  53 . A current from a signal source located at one end of the coaxial cable flows through the center conductor  51  to a load on the other end side, and furthermore passes through the external conductor  53  to return to the signal source on the one end side. 
     As illustrated in  FIG. 6B , if the outer diameter of the center conductor  51  of the coaxial cable is defined as d, the inner diameter of the external conductor  53  is defined as D, and the dielectric constant of the dielectric  52  is ε the impedance Z of the coaxial cable is represented by the following formula. 
     
       
         
           
             
               
                 
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     As illustrated in  FIG. 6C  and  FIG. 6D , in the coaxial cable, lines of electric force (indicated by arrows) are induced radially from the center conductor  51 , and the lines of electric force and flux lines (dotted line) orthogonal to the lines of electric force form a transmission path and do not leak to the outside. On the other hand,  FIG. 7A  and  FIG. 7B  illustrate the configuration of a microstrip line in which a conductor line  55  is provided on one surface of a dielectric board  54 , and a ground conductor surface  56  is provided on the other surface of the dielectric board  54 . High-frequency signals are transmitted from a coaxial cable to a surface circuit represented by a microstrip line, and are converted into the shape of flux line and lines of electric force as illustrated in  FIG. 7B . 
     As is apparent from  FIG. 7B , radial lines of electric force in the coaxial cable are almost confined between the conductor line  55  and the ground conductor surface  56  that are located above and below each other. During the process of conversion, almost half of the radial lines of electric force are not transmitted. Radiation of high-frequency signals can be prevented, and also less attenuated transmission of the high-frequency signals becomes possible by arranging what is called a conductor line and a grounded portion such that the distance therebetween becomes short. When the input connector  13  is connected to the circuit board  12 , it is also necessary to adopt the conditions mentioned above, and desired results have conventionally been realized by know-how acquired through cut-and-try. 
     In recent years, the performance of personal computers has been enhanced, and the computational capability has improved significantly. Thereby, simulations of such discontinuous points have become possible. It can be known that, for efficient transmission to the surface circuit, rather than modifying the shape of a connector, it is effective to make a connection of the grounded section with the board sufficiently large, and also make narrow the gap between the conductor line and the grounded section disposed on the same layer. Qualitatively, signals that are undesirably radiated at discontinuous portions become part of losses. 
     In the present technology, the portion near the connector connecting section is designed in according with the basic theory mentioned above, and it is found that a connection with a ground potential established by the auxiliary piece  14  is the most effective connection. 
     2. Second Embodiment of Present Technology 
     Next, a second embodiment of a tuner module according to the present technology is explained.  FIG. 8  is a perspective view illustrating a configuration example of the tuner module according to the second embodiment of the present technology.  FIG. 9  is a perspective view of a state where a circuit board is removed.  FIG. 10  is a perspective view of a state where the circuit board and an auxiliary piece are removed. 
     The second embodiment adopts a biaxial configuration obtained by adding an input connector  113  to the configuration of the first embodiment. For example, digital terrestrial broadcasting reception signals are supplied to the input connector  13 , and satellite broadcasting IF signals are supplied to the input connector  113 . The tuner module includes a tuner case  111 , a circuit board  112 , the input connectors  13  and  113 , and an auxiliary piece  114 . On one surface or both surfaces of the circuit board  112 , circuit components that constitute at least part of the tuner module are mounted. The tuner case  111  is a metallic case that functions as a shield case. Note that a lid (not illustrated) may cover part of or the entire surface of the circuit board  112 . The lid includes a material similar to the material of the tuner case  111 . 
     The tuner case  111  has a box shape including: a rectangular bottom-surface plate  111   a ; and a front-surface plate  111   b , a back-surface plate  111   c , a side-surface plate  111   d , and a side-surface plate  111   e  that are raised from the front, back, left, and right edges of the bottom-surface plate  111   a , respectively. The tuner case  111  has one open surface. In addition, hole sections  111   g  and  111   h  are screw holes for fixing the tuner module to the housing of a television receiver, for example. The circuit board  112  is attached so as to cover the open surface of the tuner case  111 . External conductors of the input connectors  13  and  113  include a metal such as iron, brass, or zinc. Base sections of the external conductors of the input connectors  13  and  113  are attached to the front-surface plate  111   b  of the tuner case  111  by non-screwing mechanical joining, screwing or the like. 
     The input connectors  13  and  113  are coaxial connectors used for supplying outputs of antennas to a tuner, for example. The input connector  113  is an F connector, for example. It should be noted, however, that, similarly to the input connector  13 , the input connector  113  may be an IEC connector. 
     The core wires of coaxial cables inserted into the input connectors  13  and  113  are each pinched by two internal spring contact points (pinching pieces). The spring contact points constitute at least part of center electrodes, and terminal sections  13   a  and  113   a  connected with the center electrodes are introduced from rear sections of the input connectors  13  and  113  into the tuner case  111  through holes formed on the front-surface plate  111   b  of the tuner case  111  (see  FIG. 10 ). 
     A plurality of leg portions projects upward from end surfaces of the side-surface plates  111   d  and  111   e  and the back-surface plate  111   c  of the tuner case  111 . Furthermore, a plurality of plate-like bodies is provided on the bottom-surface plate  111   a  of the tuner case  111 , and leg portions are provided on the upper end surfaces of the plurality of plate-like bodies. The leg portions are inserted into through holes provided as ground terminals of the circuit board  112 , and soldered. Some of the plurality of plate-like bodies are provided to surround areas of corner sections of the tuner case  111  where the respective input connectors  13  and  113  are provided. The plate-like bodies include a metal similar to the metal of the tuner case  111 , and function as shield members. Note that the auxiliary piece  114  may integrally have plate-like bodies that have similar functions. 
     In such a manner, the leg portions may penetrate holes formed through the circuit board  112 . The inner walls of the penetrating holes have through-hole structures plated with copper foils on the circuit board  112 , are connected with a ground terminal, and make the tuner case  111  serve as a uniform ground potential. In such a manner, joints can be formed around the entire circumferences of the through-hole holes of the circuit board  112  in which the leg portions of the tuner case  111  are inscribed, and the mechanical strengths of the joints can be ensured. Note that all the leg portions projecting upward from the tuner case  111  are preferably joined with the holes formed through the circuit board  112 . 
     The terminal section  13   a  of the input connector  13  and the terminal section  113   a  of the input connector  113  are bent upward at intermediate portions thereof, and the bent portions serve as leg portions  31  and  131 , respectively. The leg portions  31  and  131  may penetrate holes formed through the circuit board  112 . The holes have configurations of through holes, and serve as signal terminals on the circuit board  112 . 
     The auxiliary piece  114  is formed by bending a metal plate of a material similar to the material of the tuner case  111  into an L-shape, and has a base section  114   a  and a raised section  114   b . Center portions of the base section  114   a  and the raised section  114   b  are clipped to form an opening  114   c . The base section  114   a  of the auxiliary piece  114  is mechanically and electrically connected with the bottom-surface plate  111   a  of the tuner case  11 . Note that both the base section  114   a  and the raised section  114   b  may be mechanically and electrically connected with the tuner case  111 . The opening  114   c  is formed at a position similar to the position of the hole of the front-surface plate  111   b , and the terminal section  13   a  is introduced into the tuner case  111  through the hole and the opening  114   c . Methods that can be used for connection between the tuner case  111  and the auxiliary piece  114  include screwing, non-screwing mechanical joining, welding, soldering and the like. 
     The terminal section  13   a  is connected with the core wire of the coaxial cable connected to the connector  13 , and for suppression of radio waves radiated from the terminal section  13   a , the length of the terminal section  13   a  is preferably short. On the other hand, since the leg portion  31  at the tip of the terminal section  13   a  may penetrate a through hole formed through the circuit board  112 , it becomes difficult to form the through hole at an end section of the circuit board  112  if the length of the terminal section  13   a  is made short. Accordingly, the length of the terminal section  13   a  is made short only to the extent that the through hole can be formed at the end section of the circuit board  112 . 
     Two leg portions  32  and  33  project parallel to each other inward from an upper section of the opening  114   c  of the raised section  114   b  of the auxiliary piece  114 . The leg portions  32  and  33  have approximately similar shapes which are bent upward at intermediate portions thereof. As illustrated in  FIG. 10 , the leg portions  32  and  33  are arranged to be positioned near both sides of the leg portion  31  of the terminal section  13   a . Accordingly, in a case that the leg portions  31 ,  32 , and  33  are connected to the circuit board  112 , the connection locations on the circuit board  112  may be positioned relatively close to each other. Thereby, occurrence of unnecessary radiation can be suppressed. 
     Since the leg portions  32  and  33  are connected with the tuner case  111 , the leg portions  32  and  33  serve as ground terminals. In order to provide such ground terminals, in a possible case, the auxiliary piece  114  may not be used, but by sheet metal working, for example, an external conductor of the input connector  13  may be cut, and the cut portions may be raised. The method leads to more significant deterioration of the strength of the input connector  13 , and there is a fear that when a load is applied to the input connector  13  by a coaxial cable connected to the input connector  13  at the time of actual use, the input connector  13  may be damaged. In addition, the leg portions connected with the core wire of the input connector  13  are undesirably located closer to the input connector  13 , and there is a fear that when holes through which the leg portions are to be inserted are formed near an end section of the circuit board  112 , the circuit board  112  may be damaged. Furthermore, the method of forming the leg portions by processing of cutting the tuner case  111  itself and raising the cut portions necessitates forming holes through the tuner case  111 , and gives rise to a problem that radiation from the holes is caused. 
     In order to avoid such problems, the auxiliary piece  114  is used. The auxiliary piece  114  assists connection between the tuner case  111  and the circuit board  112  that serve as a ground potential. The base section  114   a  of the auxiliary piece  114  is in surface-contact with the bottom-surface plate  111   a  of the tuner case  111 , thereby realizing a low contact resistance. Similarly to the first embodiment, in the second embodiment, solder joints in which a direct current and a high-frequency resistance between grounds of the input connector, the nearby tuner case, and the circuit board can be made very small can also be realized, and strong connections can be established. Note that a leg portion  132  for connection with the ground terminals is provided near the terminal section  113   a  of the input connector  113 . 
     3. Third Embodiment of Present Technology 
     Next, a third embodiment of a tuner module according to the present technology is explained.  FIG. 11  is a perspective view illustrating a configuration example of the tuner module according to the third embodiment of the present technology.  FIG. 12  is a perspective view of a state where a circuit board is removed.  FIG. 13  is a perspective view of a state where the circuit board and an auxiliary piece are removed. 
     The third embodiment adopts a triaxial configuration obtained by adding an input connector  213  between the input connector  13  and the input connector  113  in the configuration in the second embodiment. For example, digital terrestrial broadcasting reception signals are supplied to the input connector  13 , and satellite broadcasting IF signals are supplied to the input connectors  113  and  213 . The tuner module includes a tuner case  211 , a circuit board  212 , the input connectors  13 ,  113 , and  213 , and an auxiliary piece  214 . On one surface or both surfaces of the circuit board  212 , circuit components that constitute at least part of the tuner module are mounted. The tuner case  211  is a metallic case that functions as a shield case. Note that a lid (not illustrated) may cover part of or the entire surface of the circuit board  212 . The lid includes a material similar to the material of the tuner case  211 . 
     The tuner case  211  has a box shape including: a rectangular bottom-surface plate  211   a ; and a front-surface plate  211   b , a back-surface plate  211   c , a side-surface plate  211   d , and a side-surface plate  211   e  that are raised from the front, back, left, and right edges of the bottom-surface plate  211   a , respectively. The tuner case  211  has one open surface. In addition, hole sections  211   g  and  211   h  are screw holes for fixing the tuner module to the housing of a television receiver, for example. The circuit board  212  is attached so as to cover the open surface of the tuner case  211 . External conductors of the input connectors  13 ,  113 , and  213  include a metal such as iron, brass, or zinc. Base sections of the external conductors of the input connectors  13 ,  113 , and  213  are attached to the front-surface plate  211   b  of the tuner case  211  by non-screwing mechanical joining, screwing or the like. 
     The input connectors  13 ,  113 , and  213  are coaxial connectors used for supplying outputs of antennas to a tuner, for example. The input connectors  113  and  213  are F connectors, for example. It should be noted, however, that, similarly to the input connector  13 , the input connectors  113  and  213  may be IEC connectors. 
     The core wires of coaxial cables inserted into the input connectors  13 ,  113 , and  213  are each pinched by two internal spring contact points (pinching pieces). The spring contact points constitute at least part of center electrodes, and terminal sections  13   a ,  113   a , and  213   a  connected with the center electrodes are introduced from rear sections of the input connectors  13 ,  113 , and  213  into the tuner case  211  through holes formed on the front-surface plate  211   b  of the tuner case  211  (see  FIG. 12 ). 
     A plurality of leg portions projects upward from end surfaces of the side-surface plates  211   d  and  211   e  and the back-surface plate  211   c  of the tuner case  211 . Furthermore, a plurality of plate-like bodies is provided on the bottom-surface plate  211   a  of the tuner case  211 , and a plate-like body  214   d  is provided on the auxiliary piece  214  mentioned below. Leg portions are provided on the upper end surfaces of the plate-like bodies. The leg portions are inserted into through holes provided as ground terminals of the circuit board  112 , and soldered. Some of the plurality of plate-like bodies are provided to surround areas of the tuner case  211  where the respective input connectors  13 ,  113 , and  213  are provided. The plate-like bodies include a metal similar to the metal of the tuner case  211 , and function as shield members. 
     In such a manner, the leg portions may penetrate holes formed through the circuit board  212 . The inner walls of the penetrating holes have through-hole structures plated with copper foils on the circuit board  212 , are connected with a ground terminal, and make the tuner case  211  serve as a uniform ground potential. In such a manner, joints can be formed around the entire circumferences of the through-hole holes of the circuit board  212  in which the leg portions of the tuner case  211  are inscribed, and the mechanical strengths of the joints can be ensured. Note that all the leg portions projecting upward from the tuner case  211  are preferably joined with the holes formed through the circuit board  212 . 
     The terminal section  13   a  of the input connector  13 , the terminal section  113   a  of the input connector  113 , and the terminal section  213   a  of the input connector  213  are bent upward at intermediate portions thereof, and the bent portions serve as leg portions  31 ,  131 , and  231 , respectively. The leg portions  31 ,  131 , and  231  may penetrate holes formed through the circuit board  212 . The holes have configurations of through holes, and serve as signal terminals on the circuit board  212 . 
     The auxiliary piece  214  is formed by bending a metal plate of a material similar to the material of the tuner case  211  into an L-shape, and has a base section  214   a  and a raised section  214   b . Center portions of the base section  214   a  and the raised section  214   b  are clipped to form an opening  214   c . In addition, the auxiliary piece  214  has the plate-like body  214   d  as a shield member between the input connectors  113  and  213 . The base section  214   a  of the auxiliary piece  214  is mechanically and electrically connected with the bottom-surface plate  211   a  of the tuner case  211 . Note that both the base section  214   a  and the raised section  214   b  may be mechanically and electrically connected with the tuner case  211 . The opening  214   c  is formed at a position similar to the position of the hole of the front-surface plate  211   b , and the terminal section  13   a  is introduced into the tuner case  211  through the hole and the opening  214   c . Methods that can be used for connection between the tuner case  211  and the auxiliary piece  214  include screwing, non-screwing mechanical joining, welding, soldering and the like. 
     The terminal section  213   a  is connected with the core wire of the coaxial cable connected to the input connector  213 , and for suppression of radio waves radiated from the terminal section  213   a , the length of the terminal section  213   a  is preferably short. On the other hand, since the leg portion  231  at the tip of the terminal section  213   a  may penetrate a through hole formed through the circuit board  212 , it becomes difficult to form the through hole at an end section of the circuit board  212  if the length of the terminal section  213   a  is made short. Accordingly, the length of the terminal section  213   a  is made short only to the extent that the through hole can be formed at the end section of the circuit board  212 . 
     Two leg portions  32  and  33  project parallel to each other inward from an upper section of the opening  214   c  of the raised section  214   b  of the auxiliary piece  214 . The leg portions  32  and  33  have approximately similar shapes which are bent upward at intermediate portions thereof. As illustrated in  FIG. 12 , the leg portions  32  and  33  are arranged to be positioned near both sides of the leg portion  31  of the terminal section  213   a . Accordingly, in a case that the leg portions  31 ,  32 , and  33  are connected to the circuit board  212 , the connection locations on the circuit board  212  may be positioned relatively close to each other. Thereby, occurrence of unnecessary radiation can be suppressed. 
     Since the leg portions  32  and  33  are connected with the tuner case  211 , the leg portions  32  and  33  serve as ground terminals. In order to provide such ground terminals, in a possible case, the auxiliary piece  214  may not be used, but by sheet metal working, for example, an external conductor of the input connector  13  may be cut, and the cut portions may be raised. The method leads to more significant deterioration of the strength of the input connector  13 , and there is a fear that when a load is applied to the input connector  13  by a coaxial cable connected to the input connector  13  at the time of actual use, the input connector  13  may be damaged. In addition, the leg portions connected with the core wire of the input connector  13  are undesirably located closer to the input connector  13 , and there is a fear that when holes through which the leg portions are to be inserted are formed near an end section of the circuit board  212 , the circuit board  212  may be damaged. Furthermore, the method of forming the leg portions by processing of cutting the tuner case  211  itself and raising the cut portions necessitates forming holes through the tuner case  211 , and gives rise to a problem that radiation from the holes is caused. 
     In order to avoid such problems, the auxiliary piece  214  is used. The auxiliary piece  214  assists connection between the tuner case  211  and the circuit board  212  that serve as a ground potential. The base section  214   a  of the auxiliary piece  214  is in surface-contact with the bottom-surface plate  211   a  of the tuner case  211 , thereby realizing a low contact resistance. Note that leg portions  132  and  232  for connection with the ground terminals are provided near the terminal sections  113   a  and  213   a  of the input connectors  113  and  213 , respectively. 
     In the present technology mentioned above, all the ground connecting sections between the tuner case  211  and the circuit board  212  can be soldered connections around the entire circumferences of the through-hole hole sections. Accordingly, solder joints in which a direct current and a high-frequency resistance between grounds of the input connector, the nearby tuner case, and the circuit board can be made very small can be realized. The present technology is suitable for tuner modules of advanced BS receiving devices (to be put on the market as 4K and 8K television television) that receive the frequency range that covers 3.2 GHz as a result of the future expansion of the reception band. In addition, the intervals between the inner walls of the through holes and the inserted leg portions of the tuner case  211  are very narrow, and solder melted in a reflow oven experiences capillary action and is drawn into the intervals, thereby making it possible to realize strong joints simply and conveniently. 
     Furthermore, as is apparent from the examples in the second and third embodiments, if a shield wall is installed by cutting and raising for the purpose of improving isolation between input connectors, the number of opening sections of a tuner case increases. This makes it more likely that leakage of signals and outputs of a local transmitter to the outside of a tuner module occurs. As a countermeasure against this, the auxiliary piece is arranged to block the opening sections of the tuner case. Thereby, the effect of improving connection of the ground pattern and the effect of reducing unnecessary radiation can be attained. 
     On the other hand, the use of collective application of solder by means of nozzles can be avoided, and manufacturing steps by simple and convenient solder printing by means of an aluminum screen can be adopted. Accordingly, for example, dedicated nozzles that are prepared for manufacture of uniaxial tuners and triaxial tuners having different solder connection points become unnecessary, and therefore technology and know-how necessary for the manufacturing steps become unnecessary. Then, since special facilities necessary for collective application of solder also become unnecessary, a launch, transfer, or change of a manufacture factory also becomes easy, and accordingly a huge cost-reduction effect can be expected in terms of business. Furthermore, elimination of reflow steps by collective application of solder leads to reduction of the number of times of heat stress on components to be used for modules, and contributes to enhancement of the reliability of the components. That is, this is because deterioration of molds and the like is slowed since the number of times of heating at the time of reflow decreases. 
       FIG. 14  illustrates one example of a device for measuring the effects of the present technology. That is, the configuration illustrates a system for measurement of coaxial-line shielding effects called S 4  indicated in the standard called EN55020 stipulated by the European Committee for Electrotechnical Standardization called Cenelec in Europe. A measurement-target tuner  41 , a desired signal generator  42 , a measuring probe  43 , and an EMI (Electro-Magnetic Interference: electro-magnetic interference) measurement device  44  are provided. 
     An antenna-signal input connector  41   a  of the measurement-target tuner  41  and the measuring probe  43  are connected by a coaxial cable (75Ω)  45 , and the desired signal generator  42  and the measuring probe  43  are connected by an impedance matching device  46  and a coaxial cable  47 . The impedance matching device  46  performs impedance conversion (50Ω→75Ω). A high-frequency signal generated by the desired signal generator  42  is supplied to the measurement-target tuner  41 , and a leaked signal induced to the outer covering (ground line) of the coaxial cable  45  by the measuring probe  43  is measured by the EMI measurement device  44 . Measurement is performed for determining that the shielding effect of the coaxial cable  45  does not deteriorate due to an input circuit of the measurement-target tuner  41 . 
     Table 1 illustrates one example of measurement results. Table 1 illustrates measurement values obtained by using 950 MHz with which the lowest shielding effect has been obtained. The sample without an auxiliary piece corresponds to a measurement result of a conventional tuner module, and the sample A and the sample B to which auxiliary pieces are added correspond to tuner modules to which the present technology is applied. As can be known from Table 1, the present technology can improve shielding amounts. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Samples 
                 Shielded Amounts 
               
               
                   
                   
               
             
            
               
                   
                 Without auxiliary piece 
                 63.6 dB 
               
               
                   
                 With auxiliary piece A 
                 66.3 dB 
               
               
                   
                 With auxiliary piece B 
                 67.3 dB 
               
               
                   
                   
               
            
           
         
       
     
     4. Application Example 
     For example, an IC (circuit) as a terrestrial television broadcasting (TV) tuner-module function section or an IC (circuit) as a satellite broadcasting (BS) tuner-module function section, and electronic components are formed (mounted) on the circuit boards of the tuner modules described as the first embodiment, the second embodiment, and the third embodiment mentioned above. The tuner-module boards are mounted on circuit boards of television receivers, as one example. 
     A receiving device is at least partially constituted by using any of the tuner modules. The receiving device is configured to be able to receive terrestrial television broadcasting wave signals and satellite broadcasting wave signals, for example. The receiving device has a reception antenna that receives broadcasting wave signals, a tuner module having a frequency conversion function, and a demodulating section. 
     A first system of the receiving device includes a reception antenna, an antenna connector, a filter, a low-noise amplifier (Low Noise Amplifier: LNA), a tuner section, and a demodulating section. In addition, a second system of the receiving device includes a reception antenna, an antenna connector, a filter, a low-noise amplifier (LNA), a tuner section, and a demodulating section. 
     5. Modification 
     The embodiments of the present technology are explained specifically thus far, but the present technology is not limited by the embodiments mentioned above, and various types of modifications based on the technical ideas of the present technology are possible. In addition, the configurations, methods, steps, shapes, materials, numerical values and the like of the embodiments mentioned above can be combined with each other unless such combinations result in deviation from the gist of the present technology. 
     For example, although in the first embodiment mentioned above, the input connector  13  is an IEC connector, the input connector  13  may be an F connector.  FIG. 15 ,  FIG. 16 ,  FIG. 17 , and  FIG. 18  illustrate the configuration in a case that an F connector  113  is used. Detailed explanations of the configuration are omitted since the configuration is similar to the configuration illustrated in  FIG. 1 ,  FIG. 2 ,  FIG. 3 , and  FIG. 4 , and the configuration has the leg portion  131  and the leg portions  132  and  133  of the auxiliary piece  114 . 
     Note that the present technology can have configurations like the ones mentioned below. 
     (1) 
     A tuner module including: 
     an input connector; 
     a tuner case; 
     a circuit board; and 
     an auxiliary piece, in which 
     the auxiliary piece contacts a surface of the tuner case and is fixed to the surface of the tuner case, and 
     part of the auxiliary piece is connected as a ground potential near a contact of a core wire of the input connector with the circuit board. 
     (2) 
     The tuner module according to (1), in which a plurality of input connectors is fixed to one surface of the tuner case. 
     (3) 
     The tuner module according to (1) or (2), in which the surface of the tuner case to which the auxiliary piece is fixed includes a surface to which the input connector is fixed. 
     (4) 
     The tuner module according to any one of (1) to (3), in which a hole to which the auxiliary piece is connected as the ground potential of the circuit board is formed by through-hole processing. 
     (5) 
     The tuner module according to any one of (1) to (4), in which fitting between a hole and a protrusion that are for fixation is used for a connecting portion of the auxiliary piece and the tuner case. 
     (6) 
     The tuner module according to any one of (1) to (4), in which the auxiliary piece is coupled with the surface of the tuner case by a solder joint. 
     (7) 
     The tuner module according to any one of (1) to (4), in which the auxiliary piece is coupled with the surface of the tuner case by non-screwing mechanical joining. 
     (8) 
     A receiving device including the tuner module according to (1). 
     REFERENCE SIGNS LIST 
       11 ,  111 ,  211  . . . Tuner case,  12 ,  112 ,  212  . . . Circuit board, 
       13 ,  113 ,  213  . . . Input connector,  14 ,  114 ,  214  . . . Auxiliary piece, 
       13   a ,  113   a ,  213   a  . . . Terminal section,  31 ,  131 ,  231  . . . Leg portion, 
       32 ,  132 ,  232  . . . Leg portion,  33 ,  133 ,  233  . . . Leg portion