Patent Publication Number: US-8118446-B2

Title: Discharge tube supporting structure, supporting member, discharge tube, ferrule, lighting device, display device and television receiver

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a discharge tube supporting structure, a supporting member, a discharge tube, a ferrule, a lighting device, a display device and a television receiver. 
     2. Description of the Related Art 
     An example of a lighting device capable of functioning as a backlight for a liquid crystal display device is disclosed in JP-A-2004-294592. The lighting device has a construction in which the end portions of a plurality of elongated discharge tubes are fixed to respective connecting members mounted to a substantially flat plate-shaped chassis, and power boards are also fixed to the respective connecting members. An outer lead projecting from the end portion of the discharge tube is connected to the power board via the connecting member. 
     The outer lead coaxially projects from the end portion of the discharge tube, and therefore the distal end of the outer lead may interfere with a nearby component (e.g., the peripheral wall of the chassis) if the discharge tube axially displaces from the connecting members. The outer lead, which is important as an electrical connecting member, is elongated and low in strength. Therefore, the interference of the outer lead with the nearby component should be prevented. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing circumstances, preferred embodiments of the present invention have a structure to restrict the axial movement of a discharge tube. 
     A discharge tube supporting structure according to a preferred embodiment of the present invention is arranged to support at least one discharge tube on a chassis. The discharge tube includes a glass tube and a ferrule that has a substantially cylindrical shape and is fitted to at least one end portion of the glass tube. The discharge tube supporting structure includes at least one supporting member, which is arranged on the chassis so as to be capable of supporting the discharge tube. A stopper is arranged on the supporting member so as to be capable of locking the ferrule and thereby restricting axial movement of the discharge tube. 
     According to a preferred embodiment of the present invention, when a discharge tube is supported on supporting members, the stopper locks the ferrule. Therefore, the discharge tube is secure from axial movement relative to the supporting members. 
     Other features, elements, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the present invention with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of a television receiver according to a preferred embodiment 1 of the present invention. 
         FIG. 2  is a horizontal sectional view of a display device. 
         FIG. 3  is a front perspective view of a lighting device. 
         FIG. 4  is a front view of the lighting device. 
         FIG. 5  is a perspective view of relay connectors. 
         FIG. 6  is a partially-enlarged front view showing a connecting structure between a relay connector and a discharge tube. 
         FIG. 7  is a side view of a relay connector. 
         FIG. 8  is a sectional view showing that the ferrule of a discharge tube is capable of engaging with a stopper. 
         FIG. 9  is a sectional view showing a connecting structure between a relay connector and a power board. 
         FIG. 10  is a perspective view of a discharge tube. 
         FIG. 11  is a rear view of a ferrule. 
         FIG. 12  is a plan view of the ferrule. 
         FIG. 13  is a side view of the ferrule. 
         FIG. 14  is a rear perspective view of the lighting device. 
         FIG. 15  is a front view of a lighting device according to a preferred embodiment 2 of the present invention. 
         FIG. 16  is a front view showing the lighting device, from which discharge tubes are detached. 
         FIG. 17  is a rear view of the lighting device. 
         FIG. 18  is a perspective view of a grounding member. 
         FIG. 19  is a perspective view of a grounding terminal. 
         FIG. 20  is a sectional view showing that the ferrule of a discharge tube is capable of engaging with a stopper. 
         FIG. 21  is a partially-enlarged front view showing a connecting structure between a grounding terminal and a discharge tube. 
         FIG. 22  is a perspective view showing a modification of a ferrule. 
         FIG. 23  is a side view of  FIG. 22 . 
         FIG. 24  is a perspective view of a grounding terminal. 
         FIG. 25  is a sectional view showing a connection between a grounding terminal shown in  FIG. 24  and a ferrule. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Preferred Embodiment 1 
     Preferred embodiment 1 according to the present invention will be hereinafter explained with reference to  FIGS. 1 to 14 . 
     Overview of Display Device D 
     A display device D is a so-called liquid crystal display device, which generally has a horizontally-elongated rectangular shape and includes a display panel  11  and a lighting device  10  as shown in  FIG. 2 . The display panel  11  is disposed on the front side of the lighting device  10 , so that the lighting device  10  as a backlight can illuminate the display panel  11  from the back side. The display device D can be used in a television receiver, for example. As shown in  FIG. 1 , the television receiver includes the display device D, and front and back cabinets Ca and Cb capable of holding the display device D therebetween. Further included are a power source P other than a power board  16  (corresponding to a power source according to a preferred embodiment of the present invention) described below, a tuner T and a stand S.  FIG. 2  schematically shows the display device D, and therefore the shapes of relay connectors  14  (corresponding to a supporting member of the present invention), on-board connectors  18  and the like differ slightly from those in the other figures. 
     The display panel  11  has a well-known construction, in which liquid crystal as a material with an optical property that changes with applied voltage is disposed in the gap between a transparent TFT substrate and a transparent CF substrate. TFTs (Thin Film Transistors), as switching elements connected to a source wiring line and a gate wiring line running at right angles to each other, and pixel electrodes connected to the TFTs are provided on the TFT substrate. A color filter, on which pixels of three primary colors, i.e., Red (R), Green (G) and Blue (B), are arranged in a matrix, and a common electrode are provided on the CF substrate. 
     Overview of Lighting Device  10   
     The lighting device  10  includes a lamp unit  12  and power boards  16 . The lamp unit  12  includes a metallic chassis  13 , which generally has a horizontally-elongated rectangular plate configuration and functions as a reflector plate. Further included are a plurality of discharge tubes  15  held in a horizontal position and vertically arranged on the front side of the chassis  13  so as to be parallel or substantially parallel to one another, and a plurality of relay connectors  14  which are vertically arranged along the lateral edges of the chassis  13  so as to correspond to the discharge tubes  15 . The power boards  16  are disposed on the back side of the chassis  13  so as to supply power to the discharge tubes  15  via the relay connectors  14 . 
     A plurality of substantially rectangular mounting holes  13 H corresponding to the ends of the discharge tubes  15  are formed through the chassis  13  so as to extend from the front side to the back side, and are vertically arranged to be level with the respective discharge tubes  15 . The relay connectors  14  are mounted through the respective mounting holes  13 H. 
     Relay Connector  14   
     Each relay connector  14  includes a holder  20  made of synthetic resin, and a relay terminal  31  (corresponding to a connecting terminal according to a preferred embodiment of the present invention) that is housed in the holder  20  and made of metal (e.g., stainless steel). 
     The holder  20  includes a box-shaped portion  21  that defines a block-shaped configuration as a whole, and further includes a wall portion  22  that projects backward from the back surface of the box-shaped portion  21 . 
     A container room  23  is formed in the box-shaped portion  21 , so as to have an opening extending from the front side to the lateral side (i.e., the lateral side on the opposite side of the lateral edge portion of the chassis  13 ). The front opening portion of the opening of the container room  23  is provided as a receiving opening  24 , into which an end portion (or ferrule  36 ) of the discharge tube  15  is fitted from the front side. The lateral opening portion is provided as an escape opening  25  for preventing interference with the glass tube  34  when the end portion of the discharge tube  15  is held in the container room  23 . A stopper  26  is formed on the escape opening  25 , so as to bulge inward from the opening edge and define a plate-shape configuration. Due to the stopper  26 , the escape opening  25  is narrowed so as to define a substantially U-shaped opening. The vertical size of the substantially U-shaped escape opening  25  is preferably set to be smaller than the inner diameter of the body  37  of the ferrule  36  and be equal to or slightly larger than the outer diameter of the glass tube  34  of the discharge tube  15 . On the escape opening  25 , a concave portion  27  having a semicircular shape is provided on the far end portion of the opening edge. The radius of curvature of the concave portion  27  is preferably set to be equal to or slightly larger than the radius of curvature of the outer circumference of the glass tube  34 . On the escape opening  25 , a pair of upper and lower guiding portions  28  are provided on areas of the opening edge on the front side of the concave portion  27 . 
     On the box-shaped portion  21 , an extended portion  29  extending parallel or substantially parallel to the chassis  13  is provided on the lateral surface of the box-shaped portion  21  that includes the escape opening  25 . The extended portion  29  extends so as to separate the front surface of the chassis  13  from the escape opening  25 . A pair of upper and lower retaining protrusions  30  are provided on the outer surface (i.e., upper surface and lower surface) of the box-shaped portion  21 . 
     The relay terminal  31  is held within the holder  20 . The relay terminal  31  can be formed by bending a metallic plate that is formed into a predetermined shape by punching. The relay terminal  31  includes a pair of vertically symmetrical elastic pressing portions  32  formed of curved plates, and further includes a board connecting portion  33  formed as a flat plate-shaped portion that projects to the back side. The pair of elastic pressing portions  32 , which are housed in the container room  23 , can deflect elastically and vertically so as to increase distance therebetween. The vertical distance between the pair of elastic pressing portions  32  is shortest at a position corresponding to the front side of the concave portion  27  of the stopper  26 . The minimum distance between the elastic pressing portions  32 , when the elastic pressing portions  32  are not forced into elastic deflection or are in a free state, is set to be smaller than the outer diameter of the body  37  of the ferrule  36  attached on the discharge tube  15 . On the other hand, the board connecting portion  33  projects from the back surface of the box-shaped portion  21  so as to be exposed to the outside of the holder  20 , and extends backwards along the wall portion  22 . 
     When the relay connector  14  is mounted to the chassis  13 , the wall portion  22  of the holder  20  is inserted into a mounting hole  13 H from the front side of the chassis  13 . Thereby, the outer surface of the box-shaped portion  21  comes in contact with the opening edge of the mounting hole  13 H on the front surface of the chassis  13 , while the retaining protrusions  30  are locked by the opening edge of the mounting hole  13 H on the back surface of the chassis  13 . Thus, the chassis  13  is sandwiched between the outer surface of the box-shaped portion  21  on the front side and the retaining protrusions  30  on the back side. Thereby, the holder  20  is fixed to the chassis  13  so that its movement in the mounting direction (i.e., the through direction of the mounting hole  13 H) is restricted. Then, the mounting of the relay connector  14  to the chassis  13  is completed. When the relay connector  14  is attached to the chassis  13 , the box-shaped portion  21  as the front end portion of the holder  20  projects (or is exposed) to the front side of the chassis  13  while the wall portion  22  as the back end portion of the holder  20  projects (or is exposed) to the back side of the chassis  13 . 
     Discharge Tube  15   
     Each discharge tube  15  is formed of a cold cathode fluorescent tube that includes a generally elongated straight glass tube  34  having a circular cross section, and elongated metallic (e.g., nickel or cobalt metal) outer leads  35  which have a circular cross section and project linearly from the respective ends of the glass tube  34  and coaxially with the glass tube  34 . Further included are ferrules  36  attached to the respective end portions of the glass tube  34 . Mercury is encapsulated in the glass tube  34 . Each end portion of the glass tube  34  is melted into a substantially hemispherical shape by heat, and thereby defines a domed portion. The outer lead  35  penetrates the domed portion. 
     Each ferrule  36  preferably is a single-piece component, which can be formed by bending or hammering a metallic (e.g., stainless steel) plate that is formed into a predetermined shape by punching. The ferrule  36  includes a body  37  and a conductive portion  40 . The body  37  generally defines a cylindrical shape concentric with the glass tube  34 . The inner diameter of the body  37  preferably is set to be slightly larger than the outer diameter of the glass tube  34 . 
     Three pairs of elastic gripping portions  38 A,  38 B preferably are formed on the body  37  by making slit-shaped cuts in portions thereof, which are arranged at even angular intervals along the circumferential direction. 
     A first elastic gripping portion  38 A, i.e., one of a pair of elastic gripping portions  38 A,  38 B, is generally formed as a cantilevered portion extending posteriorly (specifically, in an oblique direction slightly leaning radially inwardly), which is capable of elastic and radial deflection with a supported point on its proximal end (or anterior end). A curved portion  39  is provided on the distal end portion (or posterior end portion) of the first elastic gripping portion  38 A, so as to curve in an oblique direction leaning radially outwardly. The outer surface of the curve (or inwardly facing surface) of the curved portion  39  is provided as a contact point when abutting on the outer circumferential surface of the glass tube  34 . The imaginary line that connects the contact points provided on the three first elastic pressing portions  38 A forms a circle concentric with the body  37 . The diameter of the imaginary circle, when the first elastic gripping portions  38 A are not forced into elastic deflection or are in a free state, is set to be smaller than the outer diameter of the glass tube  34 . 
     A second elastic gripping portion  38 B, i.e., the other of the pair of elastic gripping portions  38 A,  38 B, is arranged circumferentially adjacent to the first elastic gripping portion  38 A, and is generally formed as a cantilevered portion extending anteriorly or reversely from the first elastic gripping portion  38 A (specifically, in an oblique direction slightly leaning radially inwardly), which is capable of elastic and radial deflection with a supported point on its proximal end (or posterior end). The distal end of the second elastic gripping portion  38 B is provided as a contact point when abutting on the outer circumferential surface of the glass tube  34 . The imaginary line that connects the contact points provided on the three second elastic gripping portions  38 B forms a circle concentric with the body  37 . The diameter of the imaginary circle, when the second elastic gripping portions  38 B are not forced into elastic deflection or are in a free state, is preferably set to be smaller than the outer diameter of the glass tube  34 . 
     On the body  37 , a pair of protector portions are formed as cantilevered portions protruding anteriorly from the anterior end edge thereof. The pair of protector portions are arranged circumferentially spaced apart, and extend linearly from the body  37  so as to be flush therewith. The conductive portion  40  is provided as a cantilevered portion that extends anteriorly from between the pair of protector portions. The conductive portion  40  includes along portion  41  continuous with the anterior end of the body  37 , and a cylindrical portion  42  that further projects anteriorly from the anterior end (or distal end) of the long portion  41 . 
     The long portion  41  includes a proximal portion  41   a  that extends from the body  37  so as to be flush with the body  37  and parallel or substantially parallel to the axis thereof, and further includes an intermediate portion  41   b  that extends radially inwardly from the distal end of the proximal portion  41   a  toward the axis of the body  37 . Further included is a distal portion  41   c  that extends from the distal end of the intermediate portion  41   b  and parallel or substantially parallel to the axis of the body  37 . The cylindrical portion  42  is connected to the distal end of the distal portion  41   c . The width of the long portion  41  is set to be sufficiently small for the length of the long portion  41 . Therefore, the long portion  41  is capable of elastic deformation in the radial direction of the body  37 , elastic deformation in a direction intersecting with the radial direction (and intersecting with the longitudinal direction of the long portion  41 ), and elastic torsional deformation around the long portion  41  itself as the axis. 
     The cylindrical portion  42 , which can be formed by bending a portion laterally extending from the distal end of the long portion  41  into a cylindrical shape, is arranged substantially coaxially with the body  37 . The cylindrical portion  42  is capable of displacement around the axis of the ferrule  36  and radial displacement, due to elastic deflection of the long portion  41 . 
     Attachment of Ferrule  36  to Glass Tube  34   
     Next, an assembling process for attaching a ferrule  36  to a glass tube  34  will be explained. 
     During the assembling process, while a ferrule  36  and a glass tube  34  are held by respective holding devices (not shown), the ferrule  36  and the glass tube  34  are moved relatively and coaxially so as to approach each other. Thereby, the body  37  is fitted onto the glass tube  34 . When the body  37  begins engagement, the contact points provided on the distal end portions of the three pairs of elastic gripping portions  38 A,  38 B have elastic contact with the outer circumference of the glass tube  34 . The contact points slide on the outer circumferential surface of the glass tube  34 , as the assembling process proceeds. Then, the tip of the outer lead  35  having passed through the body  37  begins to enter the hollow of the cylindrical portion  42 . When both of the holding devices have thereafter reached predetermined final positions, the ferrule  36  and the glass tube  34  are axially positioned in proper positions, resulting in the tip end portion of the outer lead  35  being circumferentially surrounded by the cylindrical portion  42 . At the time, the tip end portion of the outer lead  35  will not greatly protrude from the anterior end of the cylindrical portion  42 . That is, it slightly protrudes out of the cylindrical portion  42 , or is aligned with the anterior end of the cylindrical portion  42 , or alternatively it is located within the cylindrical portion  42 . 
     Thereafter, the cylindrical portion  42  is clamped so as to deform with diameter reduction. After being clamped, the cylindrical portion  42  is electrically conductively fixed to the outer lead  35  by welding, and consequently the ferrule  36  is integrated with the glass tube  34 . Then, the assembling process terminates, and the discharge tube  15  is completed. 
     When the ferrule  36  is attached to the glass tube  34 , the body  37  is concentrically held on the glass tube  34  due to the elastic holding function of the three pairs of elastic gripping portions  38 A,  38 B. A gap (airspace) is secured between the outer circumference of the glass tube  34  and the inner circumference of the body  37 , so as to extend over the substantially entire circumference. 
     Instead of the cylindrical portion  42 , a U-shaped connecting portion  42   a  may be provided as shown in  FIGS. 22 and 23 . In this case, after a glass tube  34  is fitted into a ferrule  36 , the U-shaped connecting portion  42   a  is bended so as to hug the outer lead  35 , in order to achieve electrical connection between the outer lead  35  and the connecting portion  42   a . According to the preferred embodiment thus including the bendable U-shaped connecting portion  42   a , electrical connectivity with the outer lead  35  can be further improved. 
     Mounting of Discharge Tube  15  to Relay Connectors  14   
     The discharge tube  15 , thus assembled, is fixed to relay connectors  14 . At the time of fixation, the discharge tube  15  held in a horizontal position is moved toward the front surface of the chassis  13 , and the end portions and the ferrules  36  of the glass tube  34  are fitted into the container rooms  23  of the relay connectors  14  from the front side. At the time, the pair of elastic pressing portions  32  are pushed by the body  37  of the ferrule  36  so as to open vertically due to elastic deflection. After the body  37  has passed through the shortest-distance portions of the pair of elastic pressing portions  32 , the body  37  is pulled deep into the container room  23  due to elastic restoring forces of the elastic pressing portions  32 , resulting in the body  37  abutting on the bottom of the container room  23 . Then, the mounting of the discharge tube  15  is completed. 
     The discharge tube  15  thus mounted is held by the pairs of elastic pressing portions  32  at its end portions, and consequently is fixed to the chassis  13  via the relay terminals  31  and the holders  20  provided as the relay terminal  31  mounting bases. At the time, the weight of the discharge tube  15  is received solely by the chassis  13  via the relay connectors  14 . That is, the outer leads  35  will not be under load due to the weight of the discharge tube  15 . 
     The pair of elastic pressing portions  32  can have elastic contact with the outer circumferential surface of the body  37 , and thereby the outer lead  35  is electrically conductively connected to the relay terminal  31  via the ferrule  36 . Further, the glass tube  34  is held due to elastic restoring forces of the pair of elastic pressing portions  32 , so as to be pressed against the concave portion  27  of the stopper  26 . Therefore, when viewed along the axial direction of the discharge tube  15 , the body  37  appears to be positioned so as to partially overlap with the stopper  26 . That is, the end edge of the body  37  on the opposite side of the conductive portion  40  is axially positioned in proximity to the stopper  26  so as to be partially faced therewith. 
     The extended portion  29  is formed on the outer surface of the holder  20 , which is perpendicular to the surface of the chassis  13  and includes the escape opening  25  of the container room  23 , so as to protrude from between the chassis  13  and the escape opening  25  and extend along the surface of the chassis  13 . This results in a long creepage distance from the inside of the container room  23  to the front surface of the chassis  13 . Thereby, a leak, from the discharge tube  15  held in the container room  23  to the chassis  13  outside the holder  20 , can be prevented. 
     Overview of Power Board  16   
     Each power board  16  includes a circuit board  17  having a circuit located on its back surface (i.e., the surface on the opposite side of the chassis  13 ), electronic components  19  mounted on the back surface of the circuit board  17 , and a plurality of on-board connectors  18  mounted on the back surface of the circuit board  17 . 
     The circuit board  17  preferably has a vertically-elongated rectangular shape as a whole, and is formed using a phenolic paper-base copper-clad laminated board (known as a phenolic paper). A plurality of fitting holes  17 H having a vertically-elongated rectangular shape are formed through the circuit board  17  so as to extend from the front side to the back side. The plurality of fitting holes  17 H are arranged vertically along the lateral side edge of the circuit board  17  so as to correspond to the above-described relay terminals  31  (or relay connectors  14 ). Each on-board connector  18  includes a housing made of synthetic resin, and an output terminal (not shown) that is completely contained in the housing and made of metal (e.g., nickel silver). The on-board connectors  18  are arranged along the lateral side edge of the circuit board  17  so as to correspond to the respective fitting holes  17 H. A fitting space (not shown) is formed on the outer surface of the housing so as to correspond to the fitting hole  17 H, and the output terminal is partly exposed to the fitting space. 
     While the circuit board  17  is kept parallel or substantially parallel to the chassis  13 , the power board  16  is moved toward the chassis  13  from the back side and is fixed thereto. At the time of fixation, the wall portions  22  of the relay connectors  14  and the board connecting portions  33  arranged along the wall portions  22  penetrate the circuit board  17  through the fitting holes  17 H and are inserted into the engaging recesses  27  of the on-board connectors  18 . Thereby, the on-board connectors  18  are fitted onto the relay connectors  14 , and the output terminals are conductively connected to the relay terminals  31 . 
     Operational Effects of the Present Preferred Embodiment 
     In the present preferred embodiment, when a discharge tube  15  is supported on relay connectors  14 , the stoppers  26  lock the ferrules  36 . Therefore, the discharge tube  15  is secure from axial movement relative to the relay connectors  14 . That is, if a force is applied to the discharge tube  15  so as to cause movement to the right, the stopper  26  catches the left-adjacent ferrule  36  attached on the left end portion of the discharge tube  15  so that the movement of the discharge tube  15  to the right is restricted. If a force is applied to the discharge tube  15  so as to cause movement to the left, the stopper  26  catches the right-adjacent ferrule  36  attached on the right end portion of the discharge tube  15  so that the movement of the discharge tube  15  to the left is restricted. Thus, the axial movement of the discharge tube  15  to either right or left is restricted, and therefore the tip of the outer lead  35  is secure from hitting the wall  22  of the container room  23  on the opposite side of the escape opening  25 . 
     The stopper  26  can engage with and lock the end edge of the ferrule  36 , and therefore a hole that can engage with the stopper  26  is not required to be formed on the outer circumference of the ferrule  36 . Thereby, processing cost can be reduced, and reduction in strength of the ferrule  36  can be prevented. 
     In the case of a construction in which a stopper  26  can engage with the end edge of a ferrule  36  on the side of the conductive portion  40 , the conductive portion  40  extending from the end edge of the ferrule  36  may preclude the end edge of the ferrule  36  from engaging with the stopper  26 , when the ferrule  36  is attached at some angle about its axis. However, in the present preferred embodiment 1, the stopper  26  is preferably arranged to engage with the end edge on the opposite side of the conductive portion  40 . Therefore, the conductive portion  40  will not preclude the ferrule  36  from engaging with the stopper  26 , and consequently the ferrule  36  can infallibly engage with the stopper  26 . 
     The conductive portion  40  includes a cylindrical portion  42 , which can be circumferentially connected to the outer lead  35  so as to surround it. Thereby, the conductive portion  40  can be prevented from disengaging from the outer lead  35 . That is, the cylindrical portion  42  will not disengage from the outer lead  35  when the cylindrical portion  42  is clamped. Therefore, the conductive portion  40  can be infallibly connected to the outer lead  35 . 
     The margin for engagement of a ferrule  36  with a stopper corresponds to the dimensional difference between the outer diameters of the glass tube  34  and the ferrule  36 . In the present preferred embodiment, ferrules  36  are concentrically held on a glass tube  34  due to the elastic gripping portions  38 A,  38 B. Therefore, if the ferrule  36  is set to be large, a large dimensional difference can be secured between the inner diameter thereof and the outer diameter of the glass tube  34 . Thereby, the margin for engagement of the ferrule  36  with the stopper  26  can be increased, resulting in reliable restriction of movement of the discharge tube  15 . 
     The concave portion  27  is formed on a stopper  26 , so as to abut on or be located close to the outer circumference of a glass tube  34  when the ferrule  36  engages with the stopper  26 . Further, the pair of elastic pressing portions  32  capable of pressing the discharge tube  15  toward the concave portion  27  side are provided in the relay connector  14 . Specifically, the pair of elastic pressing portions  32  press the discharge tube  15  toward the concave portion side, obliquely from above and obliquely from below, i.e., vertically symmetrically. Thereby, the glass tube  34  is prevented from disengaging from the concave portion  27 , and therefore the engagement of the ferrule  36  with the stopper  26  can be reliably maintained. 
     The relay connector  14  is preferably formed by mounting a relay terminal  31  in a holder  20  made of synthetic resin. In the present preferred embodiment 1, the stopper  26  is formed on the synthetic-resin holder  20 . Therefore, a stopper is not required to be formed on the relay terminal  31 , and thereby the material for manufacturing the relay terminals  31  can be reduced. Considering that the material cost for synthetic resin is generally lower than that for metal, the material cost for relay connectors  14  can be reduced according to the present preferred embodiment. 
     Preferred Embodiment 2 
     Next, preferred embodiment 2 of the present invention will be explained with reference to  FIGS. 15 to 21 . In the present preferred embodiment 2, the construction of the components arranged to support a discharge tube  15  differ from those of the above preferred embodiment 1. The other constructions are similar to the above preferred embodiment 1. Therefore, the same constructions are designated by the same symbols, and explanations for the constructions, operations and effects thereof are omitted. 
     Overview of Grounding Member  50   
     In the above preferred embodiment 1, the end portions of a discharge tube  15  are preferably supported by relay connectors  14 , each of which includes a holder  20  and a relay terminal  31 . In the present preferred embodiment 2, one of the end portions of a discharge tube  15  is supported by the same relay connector  14  as the preferred embodiment 1, while the other end portion of the discharge tube  15  is supported by a grounding member  50  (corresponding to a supporting member according to a preferred embodiment of the present invention). 
     The grounding member  50  includes an elongated support plate  51  fixed to the chassis  13  so as to be along one of the lateral edge portions thereof, and further includes a plurality of grounding terminals  52  (corresponding to a connecting terminal according to a preferred embodiment of the present invention) conductively mounted on the front surface of the support plate  51 . Mounting holes  51 H are formed through the support plate  51  so as to correspond three-to-one with the grounding terminals  52 . The support plate  51  is preferably formed of a substrate or a metallic plate. 
     On the other hand, each grounding terminal  52 , which can be formed by bending a metallic (e.g., nickel silver) plate that is formed into a predetermined shape by punching, includes a base portion  53  and a pair of elastic pressing portions  54  which extend vertically symmetrically from the respective upper and lower edge portions of the base portion  53  to the front side. Further included is a stopper  55  that extends from one of the lateral edge portions of the base portion  53  to the front side. 
     The pair of elastic pressing portions  54  are provided on the lateral edge portion on the opposite side of the stopper  55 , so as to form bulging curves toward each other. The elastic pressing portions  54  are capable of elastic deflection so as to increase the distance therebetween. The minimum distance between the pair of elastic pressing portions  54 , when the elastic pressing portions  54  are free from elastic deflection, is set to be smaller than the outer diameter of the glass tube  34  of a discharge tube  15 . 
     The stopper  55  is raised from the base portion  53 , so as to form a right angle with the axis of the discharge tube  15 . A concave portion  56  is formed on the stopper  55 , so as to sag in a substantially circular arc. On a relay connector  14  of the preferred embodiment 1, a pair of guiding portions  28  rise up from the respective upper and lower sides of the concave portion  27  of the stopper  26 . However, in the present preferred embodiment 2, the heights of portions rising up from the respective upper and lower sides of the concave portion  56  of the base portion  53  are reduced to be short. That is, elements corresponding the guiding portions  28  of the preferred embodiment are not provided. Therefore, metallic material required for grounding terminals  52  can be reduced, compared to including guiding portions. 
     Three leg portions  57  are further formed on the base portion  53 , so as to be integrated therewith. Two of the three leg portions  57  are provided between the elastic pressing portions  54  and the stopper  55 , so as to project from the respective upper and lower edge portions of the base portion  53  to the opposite side of the elastic pressing portions  54  or the stopper  55  (i.e., to the back side). The remaining one of the leg portions  57  is provided on the lateral edge of the base portion  53  on the opposite side of the stopper  55 , so as to project from the intermediate position between the elastic pressing portions  54  to the opposite side of the elastic pressing portions  54  or the stopper  55  (i.e., to the back side). 
     The grounding terminal  52  is not housed in a member such as a plastic housing, i.e., barely provided, and is conductively fixed to the support plate  51  by soldering or the like so that its leg portions  57  penetrate through the mounting holes  51 H. Thus, the plurality of grounding terminals  52  are mounted to the common support plate  51 , and thereby are conductively connected to one another via the support plate  51 . Power boards are not connected to the grounding members  50 , and the support plate  51  is conductively connected to the chassis. 
     Mounting of Discharge Tube  15  to Grounding Terminal  52   
     When a discharge tube  15  is fixed to a grounding terminal  52 , the discharge tube  15  held in a horizontal position is moved toward the front surface of the chassis  13 , and the end portion and the ferrule  36  of the glass tube  34  are fitted between the pair of upper and lower elastic pressing portions  54  from the front side. At the time, the pair of elastic pressing portions  54  are pushed by the body  37  of the ferrule  36  so as to open vertically due to elastic deflection. After the body  37  has passed through the shortest-distance portions of the pair of elastic pressing portions  54 , the body  37  is pulled toward the base portion  53  side due to elastic restoring forces of the elastic pressing portions  54 , resulting in the body  37  abutting on the base portion  53 . Then, the fixation of the discharge tube  15  is completed. The other end portion of the discharge tube  15  is fixed to a relay connector  14  in a similar manner to the above preferred embodiment 1. 
     The discharge tube  15  thus mounted is supported by the relay connector  14  and the grounding member  50  at its respective end portions. The pairs of elastic pressing portions  32 ,  54  can have elastic contact with the outer circumferential surfaces of the bodies  37  of the ferrules  36 , and thereby the outer leads  35  are electrically conductively connected to the relay terminal  31  and the grounding terminal  52  via the ferrules  36 . Further, the glass tube  34  is held due to elastic restoring forces of the pairs of elastic pressing portions  54 , so as to be pressed against the concave portions  27 ,  56  of the stoppers  26 ,  55 . Therefore, when viewed along the axial direction of the discharge tube  15 , the body  37  appears to be positioned so as to partially overlap with the stopper  26  or  55 . That is, the end edge of the body  37  on the opposite side of the conductive portion  40  is axially positioned in proximity to the stopper  26  or  55  so as to be partially faced therewith. 
     As shown in  FIGS. 24 and 25 , protector portions  551  may be provided on the grounding terminal  52 . Each protector portion  551  includes a restricting portion  552  for an elastic pressing portion, and further includes an abutting portion  553  for abutting on the support plate. When the grounding terminal  52  is mounted and fixed to the support plate  51 , the abutting portions  553  abut on or are located close to the support plate  51 . If some kind of external force is applied to the elastic pressing portions  54  so that they are pushed to open, they first come in contact with the restricting portions  553  during the course of opening. The abutting portions  553  serve as supports for preventing the protector portions  551  from collapsing, when an additional load is thereafter applied. The protector portions  551  are connected to the feet of the elastic pressing portions  54 , and therefore the abutting portions  553  should be formed lateral to the connection portion in order that the abutting portions  553  work. Note that abutting portions  553  located at a longer distance from the connection portion are more effective. 
     Operational Effects of the Present Preferred Embodiment 
     In the present preferred embodiment 2, when a discharge tube  15  is supported on a relay connector  14  and a grounding member  50 , the stopper  26  of the holder  20  and the stopper  55  of the grounding terminal  52  lock the ferrules  36  on the respective ends of the discharge tube  15 . Therefore, the discharge tube  15  is secure from axial movement relative to the relay connector  14 . 
     That is, if a force is applied to the discharge tube  15  so as to cause movement from the relay connector  14  side to the grounding member  50  side, the ferrule  36  attached on the end portion of the discharge tube  15  on the relay connector  14  side is caught by the stopper  26  of the holder  20  so that the movement of the discharge tube  15  to the grounding member  50  side is restricted. If a force is applied to the discharge tube  15  so as to cause movement from the grounding member  50  side to the relay connector  14  side, the ferrule  36  attached on the end portion of the discharge tube  15  on the grounding member  50  side is caught by the stopper  55  of the grounding terminal  52  so that the movement of the discharge tube  15  to the relay connector  14  side is restricted. Thus, the axial movement of the discharge tube  15  to either right or left is restricted, and therefore the tip of the outer lead  35  is securely prevented from hitting the wall of the container room  23  on the opposite side of the escape opening  25  or hitting the sidewall of the chassis  13 . 
     The concave portion  56  is formed on the stopper  55  of a grounding terminal  50 , so as to abut on or be located close to the outer circumference of a glass tube  34  when the ferrule  36  is in engagement with the stopper  55 . Further, the pair of elastic pressing portions  54  capable of pressing the discharge tube  15  toward the concave portion  56  side are provided on the grounding terminal  52 . Specifically, the pair of elastic pressing portions  54  press the discharge tube  15  toward the concave portion  56  side, obliquely from above and obliquely from below, i.e., vertically symmetrically. Thereby, the glass tube  34  is prevented from disengaging from the concave portion  56 , and therefore the engagement of the ferrule  3  with the stopper  55  can be reliably maintained. 
     On the grounding member  50 , the stoppers  55  are integrated with the respective grounding terminals  52  provided as a structure to provide conductive connection to the ferrules  36 . Thereby, the number of components can be reduced in the present preferred embodiment 2, compared to including stoppers provided as separate members from the grounding terminals. 
     Other Preferred Embodiments 
     The present invention is not limited to the preferred embodiments described above. The following preferred embodiments may be included in the technical scope of the present invention, for example. 
     The engagement of a ferrule with a stopper is not limited to being formed at an axial end edge of the ferrule. An engaging portion for engagement with the stopper may be formed on the ferrule so as to be axially positioned at substantially the center of the ferrule. 
     Stoppers may be arranged so that two of the stoppers can engage with one ferrule. In this case, the axially spaced stoppers can lock the ferrule so as to hold the ferrule therebetween. According to the construction, it is only necessary to provide stoppers for engagement with the ferrule attached on one of the end portions of each discharge tube. However, stoppers for engagement with the ferrules attached on both end portions of each discharge tube may be provided, so that two of the stoppers can engage with each ferrule. 
     The stopper and the ferrule may be arranged along the axial direction so that the stopper on the axial end side locks the ferrule on the central side. 
     The stopper is not limited to being formed into a circumferentially continuous circular arc, but rather may be formed of a plurality of circumferentially spaced portions. 
     The elastic gripping portions may be eliminated from a ferrule, so that the ferrule itself has elastic contact with the outer diameter of a glass tube when attached on the glass tube. In this case, the margin for engagement of the ferrule with a stopper corresponds to the plate thickness of the ferrule. 
     The radius of curvature of the concave portion of a stopper is not limited to being substantially equal to the radius of curvature of the outer circumference of the glass tube of a discharge tube. It may be set to be larger than the radius of curvature of the outer circumference of the glass tube. 
     A single elastic pressing portion may be provided, so as to be arranged across a discharge tube from the concave portion. 
     The elastic pressing portions may be arranged to abut on the glass tube of a discharge tube, instead of abutting on the ferrule. In this case, a member that is arranged to make conductive contact with the ferrule will preferably be provided separately from the elastic pressing portions. 
     The concave portion is not limited to being formed into a circular arc, but rather may be formed into a non-circular shape such as elliptical, trapezoidal or triangular shape. 
     The stopper may be formed on the connecting member mounted to a holder, instead of being formed on the holder. 
     The connecting portion provided on a conductive portion for connection to an outer lead is not limited to being formed into a cylindrical shape circumferentially surrounding the outer lead, but rather may be substantially U-shaped or V-shaped. Alternatively, a plate-shaped distal end portion may be provided on the conductive portion so as to have contact with the outer periphery of the outer lead. In this case, a valley, into which the outer lead is fitted, may be formed on the plate-shaped distal end portion of the conductive portion. 
     The display panel of the display device is not limited to having TFTs as switching elements, but rather may include, as switching elements, elements other than TFTs such as MIM (Metal Insulator Metal) elements. 
     The display device is not limited to a liquid crystal display device. Various display devices requiring a lighting device on the back side of a display panel can be included. 
     The connecting portion provided on a relay connector for connection to a power board is not limited to being formed as a protrusion, but rather may be formed as a recess. In this case, the connecting portions provided on the power board for connection to relay connectors should be formed as protrusions. 
     The power source is not limited to a power board that includes electronic components mounted on a circuit board, but rather may be provided by connecting electronic components by wires without using a circuit board. 
     The on-board connectors may be eliminated from a circuit board, so that relay connectors are connected to the power source (or power board) via cables. 
     The on-board connectors of the power source may be mounted on the chassis-side surface or front surface of the circuit board. 
     A metallic material other than stainless steel may be used for ferrules. Alternatively, a nonmetallic material, such as a conductive resin or a conductive rubber, may be used instead. 
     The outer leads, linearly projecting from a glass tube, are not limited to being arranged concentrically with the glass tube, but rather may be arranged radially eccentrically with respect to the axis of the glass tube. 
     The outer leads, linearly projecting from a glass tube, are not limited to being arranged parallel or substantially parallel to the axis of the glass tube, but rather may be arranged at an angle with the axis of the glass tube. 
     The outer leads may be arranged obliquely or crookedly. 
     The discharge tube is not limited to a cold cathode fluorescent tube. A hot cathode fluorescent tube, a xenon tube or the like may be used instead. 
     The body of a ferrule is not limited to having a cylindrical shape, but rather may be ring-shaped or substantially C-shaped. 
     The number of elastic gripping portions is not limited to three pairs, but rather may be two or less pair, or four or more pairs. Further, the elastic gripping portions may be provided as singles, instead of in pairs, which are arranged circumferentially spaced apart. 
     The elastic gripping portions are not limited to being formed of cantilevered portions extending anteriorly or posteriorly, but rather may be formed of two-point supported portions which are supported on the body at their anterior and posterior ends. 
     The conductive connection between a cylindrical portion and an outer lead may be achieved by soldering. 
     A metallic material other than stainless steel may be used for relay terminals. 
     A metallic material other than nickel silver may be used for output terminals. 
     In the preferred embodiment 2, a metallic material other than nickel silver may be used for grounding terminals. 
     While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.