Abstract:
This display device is capable of reducing possibilities of electrical disconnection between a display element and a circuit board due to a difference between the thermal expansion coefficient of the circuit board and that of a housing. Display elements ( 10, 20 ) have lead terminals ( 12, 22, 13 ). A circuit board ( 30 ) is electrically connected to the lead terminals ( 12, 22, 13 ). A housing ( 40 ) houses the display elements ( 10, 20 ). Lead guide sections ( 50, 60 ) have through holes ( 52, 62 ), through which the lead terminals ( 12, 22, 13 ) are inserted. The housing ( 40 ) has a first aligning section ( 43 ), which is aligned with the circuit board ( 30 ). The lead guide sections ( 50, 60 ) have second aligning sections ( 51, 61 ), which are aligned with the circuit board ( 30 ), and elastic supporting sections ( 53, 63 ), which are connected to the housing ( 40 ).

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a display device in which a display element is connected to a circuit board. 
       BACKGROUND ART 
       [0002]    Conventionally, various liquid crystal display devices provided with a liquid crystal display element having a lead terminal have been proposed, for example, as disclosed in Patent Literature 1. Such a liquid crystal display device includes a liquid crystal display element having a plurality of lead terminals; a circuit board to which the lead terminals of the liquid crystal display element are connected; and a housing that retains the liquid crystal display element. The lead terminals of the liquid crystal display element are passed through the lead holes of the circuit board, and are connected electrically through soldering. 
       CITATION LIST 
     Patent Literature 
       [0000]    
       
         Patent Literature 1: Japanese Unexamined Patent Application Publication No. H08-023180 
       
     
       SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
       [0004]    However, a risk that existed was that when the housing is positioned on the circuit board, the solder that connects the lead terminals of the liquid crystal display element to the circuit board breaks due to the difference in the coefficient of thermal expansion between the circuit board and the housing, and as a result, the electrical connection between the liquid crystal display element and the circuit board is disconnected, and the desired display cannot be performed on the liquid crystal display element. 
         [0005]    The present invention has been achieved in view of the above problem, and an object thereof is to provide a display device with which the risk of breakage of the solder connecting the lead terminals of the liquid crystal display element can be reduced. 
       Means for Solving the Problem 
       [0006]    A display device comprising: a display element  10 ,  20  having a lead terminal  12 ,  22 ,  13 ; a circuit board  30  connected electrically to the lead terminal  12 ,  22 ,  13 ; a housing  40  that stores the display element  10 ,  20 ; and a lead guiding portion  50 ,  60  that has a through hole  52 ,  62  in which the lead terminal  12 ,  22 ,  13  is inserted, wherein the lead guiding portion  50 ,  60  has a positioning portion  51 ,  61  positioned in the circuit board  30 ; and an elastic support portion  53 ,  63  connected to the housing. 
         [0007]    Further, a display device according to present invention comprising: a display element  10 ,  20  having a lead terminal  12 ,  22 ,  13 ; a circuit board  30  connected electrically to the lead terminal  12 ,  22 ,  13 ; a housing  40  that stores the display element  10 ,  20 ; and a lead guiding portion  50 ,  60  that has a through hole  52 ,  62  in which the lead terminal  12 ,  22 ,  13  is inserted, wherein the housing  40  has a first positioning portion  43  positioned in the circuit board  30 , and at the same time, and the lead guiding portion  50 ,  60  includes: a second positioning portion  51 ,  61  positioned in the circuit board  30 ; and an elastic support portion  53 ,  63  connected to the housing  40 . 
         [0008]    The display device according to the present invention, wherein the display element  10 ,  20  has a liquid crystal display panel  11 ,  21 . 
         [0009]    The display device according to the present invention, comprising a light emitting element  70 ,  80  loaded on the circuit board  30  and transilluminating the liquid crystal display panel  11 ,  21 . 
       Effect of the Invention 
       [0010]    The risk of disconnection of the electric connection between the display element and the circuit board due to the difference in the coefficient of thermal expansion between the circuit board and the housing can be reduced. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a cross-sectional view illustrating a first embodiment of the present invention. 
           [0012]      FIG. 2  is an enlarged cross-sectional view illustrating the same embodiment as above. 
           [0013]      FIG. 3  is a cross-sectional view illustrating the same embodiment as above. 
           [0014]      FIG. 4  is a cross-sectional view illustrating the same embodiment as above. 
           [0015]      FIG. 5  is a cross-sectional view illustrating a second embodiment of the present invention. 
           [0016]      FIG. 6  is an enlarged cross-sectional view of the main section illustrating the same embodiment as above. 
           [0017]      FIG. 7  is a front view illustrating a third embodiment of the present invention. 
           [0018]      FIG. 8  is a perspective view illustrating the same embodiment as above. 
           [0019]      FIG. 9  is a perspective view illustrating the same embodiment as above. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0020]    Hereinafter, a first embodiment of the present invention will be described with reference to the attached drawings.  FIG. 1  through  FIG. 4  are drawings illustrating the first embodiment. 
         [0021]    A liquid crystal display device includes liquid crystal display elements  10  and  20 , a circuit board  30 , a housing  40 , lead guiding portions  50  and  60 , and light emitting elements  70  and  80 . 
         [0022]    The liquid crystal display elements  10  and  20  have liquid crystal display panels  11  and  21 , and a plurality of lead terminals  12  and  22 , respectively. The liquid crystal display panels  11  and  21  are formed by pasting a polarizing member on both front and back surfaces of a liquid crystal cell in which an NVA liquid crystal is sealed between a pair of light-transmissive substrates. The lead terminals  12  and  22  are made of metal, with one end thereof connected electrically to the circuit board  30 . The other end of the lead terminals  12  and  22  forms a U shape, and is connected electrically while sandwiching the liquid crystal display panels  11  and  21 . 
         [0023]    The circuit board  30  is made of a hard wiring board in which a wiring pattern is formed on a glass epoxy substrate, and the light emitting elements  70  and  80 , etc., are loaded thereupon. Positioning holes  31 ,  32 , and  33 , and lead holes  34  and  35  are formed in the circuit board  30 . The positioning hole  31  of the circuit board  30  is formed in the central part, and is used to position the housing  40 . The positioning hole  31  is made of a circular through hole in the front view in which a projecting portion described later is inserted. 
         [0024]    The positioning holes  32  and  33  position the lead guiding portions  50  and  60 , respectively. The lead holes  34  and  35  are holes through which the lead terminals  12  and  22  of the liquid crystal display elements  10  and  20  pass. The lead terminals  12  and  22  of the liquid crystal display elements  10  and  20  are connected electrically, with a solder  90 , to the wiring pattern on the back surface of the circuit board  30 . The circuit board  30  is locked onto the back surface of the housing  40  with an elastic locking piece (not shown in the figures). 
         [0025]    The housing  40  is made of a white resin, and includes case bodies  41  and  42  that store the liquid crystal display elements  10  and  20 ; a projecting portion (first positioning portion)  43  inserted in the positioning hole  31  of the circuit board  30 ; and reflectors  44  and  45  that reflect the illumination light emitted from the light emitting elements  70  and  80 . The projecting portion  43  of the housing is formed in the central part and has a near circular cylindrical shape with the end thereof in a hemispherical shape. The reflectors  44  and  45  are formed as one part with the case bodies  41  and  42 , and are provided with openings  44   a  and  45   a  in which the light emitting elements  70  and  80  are arranged. An elastic retaining portion (not shown in the figures) that retains the liquid crystal display elements  10  and  20  is provided in the case bodies  41  and  42 . 
         [0026]    The circuit board  30  is positioned in the central part of the housing  40  due to the insertion of the projecting portion  43  of the housing  40  in the positioning hole  31 . When the housing  40  expands and contracts relatively with respect to the circuit board  30  due to the difference in the coefficient of thermal expansion between the circuit board  30  and the housing  40 , the housing  40  expands and contracts with the central part of the circuit board  30  as the center. 
         [0027]    The lead guiding portions  50  and  60  are made of a white resin, and respectively include projecting portions (second positioning portions)  51  and  61  that are inserted in the positioning holes  32  and  33  of the circuit board  30 ; and through holes  52  and  62  through which the lead terminals  12  and  22  of the liquid crystal display elements  10  and  20  pass. The lead guiding portions  50  and  60  include elastic connecting portions  53  and  63 , and are connected to the case bodies  41  and  42  of the housing  40  with the elastic connecting portions  53  and  63 . The elastic connecting portions  53  and  63  of the lead guiding portions  50  and  60  bend in an S shape in the side view. The case bodies  41  and  42  and the lead guiding portions  50  and  60  are formed as one part through the elastic connecting portions  53  and  63 . 
         [0028]    The light emitting elements  70  and  80  are made of surface-mounted light emitting diodes, and are electrically connected to the wiring pattern in the front surface of the circuit board  30 . The liquid crystal display elements  10  and  20  are transilluminated by the illumination light emitted from the light emitting elements  70  and  80 . 
         [0029]      FIG. 5  and  FIG. 6  illustrate a second embodiment. In the second embodiment, particularly, the lead terminal  13  is different from that in the first embodiment, but the other configuration is the same as that in the first embodiment. Therefore, the same reference numerals are used for the same or equivalent configuration, and the detailed explanation thereof is omitted. 
         [0030]    The liquid crystal display element  10  includes a liquid crystal display panel  11  and a plurality of lead terminals  13 . The liquid crystal display panel  11  is retained in the case body  41  with an elastic retaining portion (not shown in the figures). The lead terminal  13  is formed in a curved shape, with one end thereof connected electrically to the circuit board  30  with the solder  90 . The other end of the lead terminal  13  forms a U shape, and is connected electrically while sandwiching the liquid crystal display panel  11 . The lead terminal  13  is in contact with the through hole  52  of the lead guiding portion  50 , and the lead hole  34  of the circuit board  30 , at the side of the reflector  44 . 
         [0031]    As described in the second embodiment, by bringing the lead terminal  13  in contact with the lead hole  34  of the circuit board  30 , even when the housing  40  is inverted before one end of the lead terminal  13  is soldered on to the circuit board  30 , the liquid crystal display element  11  can be retained in the housing  40 , which makes an assembly task of the display device easier. 
         [0032]      FIG. 7  through  FIG. 9  illustrate a third embodiment. In the third embodiment, particularly, the elastic connecting portions  55  and  65  are different from those in the first embodiment. The other configuration is assigned with the same reference numerals as those in the first embodiment and the detailed explanation thereof is omitted. 
         [0033]    The lead guiding portions  50  and  60  include elastic connecting portions  55  and  65  and are connected to the housing  40  with the elastic connecting portions  55  and  65 . The elastic connecting portions  55  and  65  bend in a crank shape in the front view. The housing  40  and the lead guiding portions  50  and  60  are formed as one part through the elastic connecting portions  55  and  65 . 
         [0034]    According to each of the embodiments, because the lead guiding portions  50  and  60  are positioned in the positioning holes  32  and  33  of the circuit board  30 , the position of the through holes  52  and  62  of the lead guiding portions  50  and  60 , and the position of the lead holes  34  and  35  of the circuit board  30  match, which makes it easier to insert the lead terminals  12 ,  22 , and  13  of the liquid crystal display elements  10  and  20  into the lead holes  34  and  35  of the circuit board  30 . Moreover, the stress due to the difference in the coefficient of thermal expansion between the circuit board  30  and the housing  40  can be absorbed by the elastic connecting portions  53 ,  63 ,  55 , and  65 , and the breakage of the solder  90  that electrically connects the lead terminals  12 ,  22 , and  13  of the liquid crystal display elements  10  and  20  to the circuit board  30  can be prevented. 
         [0035]    It must be noted that the present invention is not limited to each of the above embodiments, and can have various modifications. For example, in each of the embodiments, the housing  40  is positioned by inserting the projecting portion  43  of the housing  40  in the positioning hole  31  of the circuit board  30 , however, the circuit board  30  may be secured onto the central part of the housing  40  with screws. Furthermore, the reflectors  44  and  45  are provided in the case bodies  41  and  42 , but may be provided in the lead guiding portions  50  and  60 . Furthermore, the display element in each of the embodiments is the liquid crystal display element  10 ,  20 , but the display element can also be an organic EL display element, for example. 
       INDUSTRIAL APPLICABILITY 
       [0036]    The present invention can be used in a display device in which a display element is connected to a circuit board. 
       DESCRIPTION OF REFERENCE NUMERALS 
       [0000]    
       
         
           
               10  Liquid crystal display element (display element) 
               11  Liquid crystal display panel 
               12  Lead terminal 
               13  Lead terminal 
               22  Lead terminal 
               20  Liquid crystal display element (display element) 
               21  Liquid crystal display panel 
               30  Circuit board 
               40  Housing 
               43  Projecting portion (first positioning portion) 
               50  Lead guiding portion 
               51  Projecting portion (second positioning portion) 
               52  Through hole 
               60  Lead guiding portion 
               61  Projecting portion (second positioning portion) 
               62  Through hole 
               63  Elastic support portion 
               53  Elastic support portion 
               70  Light emitting element 
               80  Light emitting element