Backlight module, backlight module manufacturing method, lighting device, display device and television receiver

In a backlight module, when relay connectors exposed to a back side of a chassis are engaged with the connector portions of a lighting jig, the power from the power supply source of the lighting jig is supplied to discharge tubes via the connector portions and the relay connectors. Thereby, the discharge tubes can be lighted, even if a power board is not connected to the relay connectors. At the time, the lighting jig is arranged to face the back surface of the chassis, and therefore optical sheets can be mounted to the chassis from the front side.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a backlight module, a backlight module manufacturing method, 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 discharge tubes are arranged on the front side of a substantially flat plate-shaped chassis while power boards are arranged on the back side of the chassis. The power from the power boards can be supplied to the discharge tubes via relay brackets mounted to the chassis.

In the lighting device, optical sheets are mounted to the chassis from the front side so as to cover the discharge tubes. During the process of mounting the optical sheets, an inspection of the optical sheets is concurrently performed. That is, at the time of mounting, the surfaces of the optical sheets are visually checked in order to detect a faulty optical sheet, and dust elimination is performed, if necessary.

When the optical sheets are thus inspected, the discharge tubes are preferably lighted in order to improve inspection accuracy. The power supply from the power boards mounted to the chassis can be provided to light the discharge tubes.

In a manufacturing process of a lighting device, the partially-finished assembly may be transported to another assembly plant when the assembling is partially finished, so that the assembling is continued at the destination plant. The following case can be assumed as an example of assembling thus performed. A backlight module, in which discharge tubes, relay terminals and optical sheets are attached to a chassis but power boards are not attached to the chassis, is assembled and transported to another assembly plant.

However, during the assembly of this form of backlight module, the power supply from power boards to the discharge tubes is impossible, and therefore the mounting of the optical sheets must be performed with the unlighted discharge tubes. Thereby, the accuracy in inspection of the optical sheets may be deteriorated.

SUMMARY OF THE INVENTION

In view of the foregoing circumstances, preferred embodiments of the present invention were developed to enable mounting of optical sheets to be performed with lighted discharge tubes without mounting a power board.

A backlight module according to a preferred embodiment of the present invention includes a chassis having a substantially plate-shaped configuration, a relay connector mounted to the chassis, a discharge tube arranged on the front side of the chassis and connected to the relay connector, and an optical member mounted to the chassis from the front side so as to cover the discharge tube. A lighting device, to be used in a display device for illuminating a display panel from a back side, can be formed by connecting a power board to the relay connector. The relay connector is arranged to be exposed to the back side of the chassis, and a connecting portion provided on the relay connector for connection to the power board is capable of conductive engagement with a connector portion of a lighting jig that includes a power supply source and the connector portion connected to the power supply source.

According to a preferred embodiment of the present invention, the power from the power supply source of the lighting jig is supplied to the discharge tube via the connector portion and the relay connector, when the relay connector exposed to the back side of the chassis is engaged with the connector portion of the lighting jig. Thereby, the discharge tube can be lighted, even if the power board is not connected to the relay connector. At the time, the lighting jig is arranged to face the back surface of the chassis, and therefore the optical member can be mounted to the chassis from the front side.

In the backlight module according to a preferred embodiment of the present invention described above, each of the mounting direction of the discharge tube to the relay connector and the mounting direction of the power board to the relay connector can be set to be substantially perpendicular to the surface of the chassis.

In this case, the discharge tube and the power board can be mounted to the chassis so as to define a stack structure, because each of the mounting direction of the discharge tube to the relay connector and the mounting direction of the power board to the relay connector preferably is set to be substantially perpendicular to the surface of the chassis.

A backlight module manufacturing method according to another preferred embodiment of the present invention is provided for manufacturing a backlight module that includes a chassis having a substantially plate-shaped configuration, a relay connector mounted to the chassis, a discharge tube arranged on the front side of the chassis and connected to the relay connector, and an optical member mounted to the chassis from the front side so as to cover the discharge tube. A lighting device, to be used in a display device for illuminating a display panel from the back side, can be formed by connecting a power board to the relay connector. In a state of the relay connector being arranged to be exposed to the back side of the chassis and a connecting portion for connection to the power board being provided on the relay connector so as to be capable of conductive connection to a connector portion of a lighting jig that includes a power supply source and the connector portion connected to the power supply source, the backlight module manufacturing method includes engaging the relay connector, disconnected from the power board, with the connector portion so as to light the discharge tube connected to the relay connector, and further includes mounting the optical member to the chassis while the discharge tube is lighted.

According to a preferred embodiment of the present invention, the power from the power supply source of the lighting jig is supplied to the discharge tube via the connector portion and the relay connector, when the relay connector exposed to the back side of the chassis is engaged with the connector portion of the lighting jig. Thereby, the discharge tube can be lighted, even if the power board is not connected to the relay connector. At the time, the lighting jig is arranged to face the back surface of the chassis, and therefore the optical member can be mounted to the chassis from the front side.

In the backlight module manufacturing method according to a preferred embodiment of the present invention described above, each of the mounting direction of the discharge tube to the relay connector and the mounting direction of the power board to the relay connector can be set to be substantially perpendicular to the surface of the chassis.

In this case, the discharge tube and the power board can be mounted to the chassis so as to define a stack structure, because each of the mounting direction of the discharge tube to the relay connector and the mounting direction of the power board to the relay connector is set to be substantially perpendicular to the surface of the chassis.

A lamp unit according to a preferred embodiment of the present invention includes a chassis having a substantially plate-shaped configuration, a relay connector mounted to the chassis, and a discharge tube arranged on the front side of the chassis and connected to the relay connector. A lighting device, to be used in a display device for illuminating a display panel from the back side, can be formed by mounting an optical member to the chassis from the front side so as to cover the discharge tube and connecting a power board to the relay connector. The relay connector is arranged to be exposed to the back side of the chassis, and a connecting portion for connection to the power board is provided on the relay connector so as to be capable of conductive engagement with a connector portion of a lighting jig that includes a power supply source and the connector portion connected to the power supply source.

According to various preferred embodiments of the present invention, the power from the power supply source of the lighting jig is supplied to the discharge tube via the connector portion and the relay connector, when the relay connector exposed to the back side of the chassis is engaged with the connector portion of the lighting jig. Thereby, the discharge tube can be lighted, even if the power board is not connected to the relay connector. At the time, the lighting jig is arranged to face the back surface of the chassis, and therefore the optical member can be mounted to the chassis from the front side.

In the lamp unit according to a preferred embodiment of the present invention described above, each of the mounting direction of the discharge tube to the relay connector and the mounting direction of the power board to the relay connector can be set to be substantially perpendicular to the surface of the chassis.

In this case, the discharge tube and the power board can be mounted to the chassis so as to define a stack structure, because each of the mounting direction of the discharge tube to the relay connector and the mounting direction of the power board to the relay connector is set to be substantially perpendicular to the surface of the chassis.

A lighting jig according to a preferred embodiment of the present invention is used in manufacture of a backlight module that includes a chassis having a substantially plate-shaped configuration, a relay connector mounted to the chassis so as to be exposed to the front side and the back side thereof, a discharge tube arranged on the front side of the chassis and connected to the relay connector, and an optical member mounted to the chassis from the front side so as to cover the discharge tube. A lighting device, to be used in a display device for illuminating a display panel from the back side, can be formed by connecting a power board to the relay connector. The lighting jig includes a power supply source, and a connector portion connected to the power supply source. The connector portion is capable of conductive engagement with a connecting portion that is provided on the relay connector for connection to the power board. The power from the power supply source is supplied to the discharge tube connected to the relay connector, when the relay connector disconnected from the power board is engaged with the connector portion.

According to a preferred embodiment of the present invention, the power from the power supply source of the lighting jig is supplied to the discharge tube via the connector portion and the relay connector, when the relay connector exposed to the back side of the chassis is engaged with the connector portion of the lighting jig. Thereby, the discharge tube can be lighted, even if the power board is not connected to the relay connector. At the time, the lighting jig is arranged to face the back surface of the chassis, and therefore the optical member can be mounted to the chassis from the front side.

In the lighting jig according to a preferred embodiment of the present invention described above, the engaging direction of the connector portion with the relay connector can be set to be parallel or substantially parallel to the mounting direction of the discharge tube to the relay connector and to be substantially perpendicular to the surface of the chassis.

In this case, the discharge tube and the power board can be mounted to the chassis so as to define a stack structure, because each of the mounting direction of the discharge tube to the relay connector and the mounting direction of the power board to the relay connector is set to be substantially perpendicular to the surface of the chassis.

A lighting device according to a preferred embodiment of the present invention includes a backlight module according to a preferred embodiment of the present invention described above, and a power board connected to a relay connector included in the backlight module.

A display device according to a preferred embodiment of the present invention includes a lighting device according to a preferred embodiment of the present invention described above, and a display panel arranged on the front side of the lighting device.

A television receiver according to a preferred embodiment of the present invention includes a display device according to another preferred embodiment of the present invention described above.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiment 1 according to the present invention will be hereinafter explained with reference toFIGS. 1 to 9.

Overview of Display Device D and Lighting Device10

A display device D used in a television receiver TV shown inFIG. 9is a so-called liquid crystal display device, which preferably has a substantially horizontally-elongated rectangular shape and includes a display panel11and a lighting device10. The display panel11is disposed on the front side of the lighting device10, so that the lighting device10as a backlight can illuminate the display panel11from the back side. As shown inFIG. 9, 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 board16described below, a tuner T and a stand S.

The display panel11has 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 color sections 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.

The lighting device10includes a backlight module10M and power boards16.

Overview of Backlight Module10M

As shown inFIG. 1, the backlight module10M includes a lamp unit12and a plurality of sheet-shaped or plate-shaped optical sheets10S.

As shown also inFIGS. 2 and 3, the lamp unit12includes a metallic chassis13, which preferably has a substantially horizontally-elongated rectangular plate shape and functions as a reflector plate. Further included are a plurality of discharge tubes15held in a horizontal position and vertically arranged on the front side of the chassis13so as to be parallel or substantially parallel to one another, and a plurality of relay connectors14which are vertically arranged along the lateral edges of the chassis13so as to correspond to the discharge tubes15. A plurality of mounting holes13H corresponding to the ends of the discharge tubes15are formed through the chassis13so as to extend from the front side to the back side, and are vertically arranged so as to be level with the respective discharge tubes15. The relay connectors14are mounted through the respective mounting holes13H.

Each relay connector14includes a holder20made of synthetic resin, and a metallic relay terminal30housed in the holder20. The holder20is inserted into the mounting hole13H from the front side of the chassis13, and is fixed to the chassis13so as to penetrate therethrough. When attached to the chassis13, the front end portion of the holder20projects to the front side of the chassis13, while the back end portion of the holder20projects to the back side of the chassis13. A container room23is formed in the projecting portion of the holder20on the front side of the chassis13, by removing the front surface and one lateral surface thereof. A plate-shaped wall portion27is provided on the projecting portion of the holder20on the back side of the chassis13. The relay terminal30is disposed in the holder20. The relay terminal30includes a tube connecting portion31includes a pair of upper and lower plates having a substantially circular arc shape, and further includes a plate-shaped board connecting portion33projecting to the back side. The tube connecting portion31is disposed in the container room23, while the board connecting portion33is arranged along the wall portion27.

Each discharge tube15preferably is a cold cathode fluorescent tube that includes a generally elongated straight glass tube40having a circular cross section, elongated outer leads (not shown) which project linearly from the respective ends of the glass tube40and coaxially with the glass tube40, and further includes ferrules50attached to the respective end portions of the glass tube40. Mercury is encapsulated in the glass tube40. Each end portion of the glass tube40is melted into a substantially hemispherical shape by heat, and thereby forms a domed portion. The outer lead penetrates the domed portion.

Each ferrule50preferably is a single-piece component, which can be formed by bending or hammering a metallic (e.g., copper alloy) plate that is gilded and formed into a predetermined shape by punching, for example. The ferrule50, which is simplistically shown in the figures, includes a body and a conductive portion. The body generally forms a cylindrical shape, which is fitted onto the outer circumference of each end portion of the glass tube40. The conductive portion extends from the end portion of the body in an oblique direction leaning inwardly, so as to have elastic contact with the outer lead. The contact portion between the conductive portion and the outer lead is fixed by welding. The discharge tube15is mounted to the relay connectors14, so that its end portions are held in the container rooms23while the ferrules50are conductively connected to the tube connecting portions31of the relay terminals30. The mounting direction of the discharge tube15to the relay connectors14is set to be substantially perpendicular to the surface (or front surface) of the chassis13.

The optical sheets10S, which are mounted to the chassis13from the front side so as to cover the discharge tubes15, preferably define a rectangular shape having substantially the same size as the chassis13, and thereby can cover the entire area that includes the discharge tubes15. The optical sheets10S are formed of opaque materials capable of light transmission. The light from the discharge tubes15provided as linear light sources is diffused when being transmitted through the optical sheets10S. Thereby, the display panel11can be uniformly irradiated with the backlight.

Each power board16includes a circuit board17having a circuit disposed on its back surface (i.e., the surface on the opposite side of the chassis13), electronic components19mounted on the back surface of the circuit board17, and a plurality of on-board connectors18mounted on the back surface of the circuit board17.

The on-board connectors18are vertically arranged along the lateral side edge of the circuit board17so as to correspond to the respective relay connectors14. Each on-board connector18, which is simplistically shown in the figures, includes a housing made of synthetic resin, and a metallic output terminal disposed in the housing. An engaging recess is formed on the housing so as to have an opening on the front side thereof. The opening of the engaging recess is aligned with a fitting hole that is formed through the circuit board17so as to extend from the front side to the back side. The output terminal, which can be formed by bending a metallic plate that is formed into a predetermined shape by punching, includes a substantially U-shaped connecting portion capable of elastic deflection. The connecting portion is arranged and located in the engaging recess. The end portion of the output terminal on the opposite side of the connecting portion is connected to the circuit disposed on the circuit board17.

The power boards16are fixed to the relay terminals14on the back side of the chassis13. At the time of fixation, the power board16is moved toward the chassis13while the circuit board17is kept parallel or substantially parallel to the chassis13, so that the wall portion27of each relay connector14and the board connecting portion33arranged along the wall portion27penetrate the circuit board17through the fitting hole and are inserted or fitted into the engaging recess of the on-board connector18. The fitting direction (or mounting direction) of the relay connector14to the on-board connector18is set to be substantially perpendicular to the surface of the chassis13. That is, the mounting direction of the power board16to the relay connectors14is directly opposite to (or is parallel or substantially parallel to) the above-described mounting direction of the discharge tube15to the relay connector14. When the on-board connectors18have reached a proper state of being fitted onto the relay connectors14, the power board16is fixed to the chassis13by screws or other suitable fastening or connecting elements.

When the on-board connector18is fitted onto the relay connector14, the connecting portion of the on-board connector18can have elastic contact with the plate-shaped board connecting portion33of the relay connector14. Thereby, the output terminal of the on-board connector18is electrically conductively connected to the relay terminal30of the relay connector14. Thus, the power board16is connected to the discharge tube15via relay connectors14, so that the power from the power board16can be supplied to the discharge tube15.

As shown inFIGS. 4 to 6and8, the lighting jig80generally forms a flat block-shaped configuration, and its planar figure is a rectangle slightly larger than the chassis13(or, the lamp unit12or the backlight module10M). A plurality of connector portions81(specifically, the same number of connector portions as relay connectors14) are embedded in the upper surface of the lighting jig80, and are arranged in a line along the lateral edges thereof. The distance between adjacent connector portions81is preferably set to be the same as the distance between adjacent relay connectors14. A recess portion82is formed on each connector portion81so as to have an opening on the upper side thereof, and a connecting terminal83is provided in the recess portion82. The recess portion82may be the same in form as the engaging recess of the on-board connector18, or alternatively, may differ in form from the engaging recess. In any case, it should be formed so that the wall portion27and the board connecting portion33of the relay connector14can be fitted into the recess portion82from above. The connecting terminal83may be the same in form as the output terminal of the power board16, or alternatively, may differ in form from the output terminal. In any case, it should be formed so that the board connecting portion33can be conductively connected to the connecting terminal83when the wall portion27and the board connecting portion33are fitted into the recess portion82.

A feed circuit84is provided in the lighting jig80. The feed circuit84connects between the connecting terminals83of the right-side connector portions81and the connecting terminals83of the left-side connector portions81. A power supply source85and an open/close switch86are provided on the feed circuit84. On the upper surface of the lighting jig80, a pair of laterally-spaced bearing portions87are formed as rib-shaped protrusions.

Manufacturing Process for Display Device D

The display device D can be manufactured in the following manner.

First, on a workbench not shown, or the like, the chassis13is horizontally placed with its front side up. Then, relay connectors14are mounted through the mounting holes13H of the chassis13, from above. The mounting direction of the relay connectors14to the chassis13is set to be substantially perpendicular to the front face of the chassis13. Next, discharge tubes15are mounted to the relay connectors14so that the end portions (or ferrules50) of each discharge tube15are fitted into the container rooms23. The mounting direction at the time is the same as the mounting direction of the relay connectors14to the chassis13, i.e., the direction substantially perpendicular to the front face of the chassis13. After the mounting of the discharge tubes15is completed, retainer88is mounted to the chassis13. The mounting direction at the time is also the same as the mounting direction of the relay connectors14to the chassis13. The retainer88can be provided as a mounting base that supports the optical sheets10S, a frame89, the display panel11and a bezel90. Note that the retainer88can be eliminated depending on the type of a display device D. The lamp unit12is thus completed.

Next, the lamp unit12is set on the lighting jig80. At the time, the lamp unit12is moved downward toward the upper surface of the lighting jig80while the chassis13is held in a horizontal position, so that the wall portion27and the board connecting portion33of each relay connector14are fitted into the recess portion82of the corresponding connector portion81. The engaging direction of the relay connectors14with the connector portions81(i.e., the mounting direction of the lamp unit12to the lighting jig80) is the same as the mounting direction of the relay connectors14to the chassis13. When the relay connectors14have reached a proper state of being fitted into the connector portions81, the lower surface (or back surface) of the chassis13have abutting contact with the upper surfaces of the connector portions81and the upper surfaces of the bearing portions87. Due to the abutting contact, the lamp unit12can be horizontally supported without a flexion deformity of the chassis13.

When the lamp unit12is set on the lighting jig80, the ferrules50of each discharge tube15are conductively connected to the feed circuit84via the relay terminals30(or relay connectors14) and via the connecting terminals83(or connector portions81). If the switch86is closed in this condition, the power from the power supply source85is supplied to all the discharge tubes15. Thereby, the discharge tubes15can be lighted, although the power boards16are not connected to the relay connectors14. While the discharge tubes15are thus lighted, the plurality of optical sheets10S are mounted on the retainer88so as to cover the upper side. At the time, the optical sheets10S are moved toward the lamp unit12while being held in a horizontal position (i.e., held substantially parallel to the chassis13). The mounting direction of the optical sheets10S is substantially the same as the mounting direction of the relay connectors14to the chassis13.

When the optical sheets10S are thus mounted, the light from the lighted discharge tubes15can be radiated to the optical sheets10S from the back side. Therefore, the inspection, or the like, for the optical sheets10S (e.g., the visual check for the surfaces of the optical sheets10S that aims to detect a faulty optical sheet10S, or the dust elimination when necessary) can be readily achieved with high accuracy.

After the mounting of the optical sheets10S is completed, the rectangular-shaped frame89is mounted to the retainer88so that the optical sheets10S are fixed with their peripheral edge portions sandwiched between the retainer88and the frame89. The mounting direction of the frame89to the retainer88is substantially the same as the mounting direction of the relay connectors14to the chassis13. When the optical sheets10S are mounted to the lamp unit12as described above, the backlight module10M is completed.

Thereafter, the display panel11is placed and mounted on the front side of the optical sheets10S so as to overlap therewith. After the mounting of the display panel11is completed, the frame-shaped bezel90is mounted to the retainer88so that the display panel11is fixed with its peripheral edge portion sandwiched between the frame89and the bezel90. Both of the mounting direction of the display panel11to the backlight module10M and the mounting direction of the bezel90are substantially the same as the mounting direction of the relay connectors14to the chassis13.

After the mounting of the display panel11and the bezel90to the backlight module10M is completed, the backlight module10M is detached from the lighting jig80, and is placed upside-down on the workbench not shown so as to face up the back surface of the chassis13. In this condition, the power boards16and a control board91(shown inFIG. 7) are mounted on the back surface of the chassis13, and are fixed by screws or other suitable fastening or connecting elements. The mounting direction of the power boards16and the control board91to the chassis13(or to the backlight module10M) is directly opposite to the mounting direction of the relay connectors14to the chassis13, i.e., parallel or substantially parallel to the mounting direction of the relay connectors14to the chassis13. At the time of mounting the power boards16, the wall portions27and the board connecting portions33of the relay connectors14are fitted into the engaging recesses of the on-board connectors18. When the power boards16are thus mounted, the board connecting portions33of the relay terminals30are conductively connected to the connecting portions of the output terminals. Therefore, the power from the power boards16can be supplied to the discharge tubes15via the relay connectors14(or relay terminals30). When the power boards16are thus mounted to the backlight module10M, the lighting device10is completed and concurrently the display device D is completed.

Effects of the Present Preferred Embodiment

As described above, in the present preferred embodiment, the relay connectors14are mounted to the chassis13so as to be exposed to the back side thereof. The wall portions27(or board connecting portions33) of the relay connectors14provided as connecting portions for connection to the power boards16are conductively engaged with the connector portions81(or connecting terminals83) of the lighting jig80, so that the power from the power supply source85of the lighting jig80can be supplied to the discharge tubes15via the connector portions81and the relay connectors14. The discharge tubes15can be thus lighted, if the power boards16are not connected to the relay connectors14. At the time, the lighting jig80is arranged to face the back surface of the chassis13, and therefore will not interfere with the mounting of the optical sheets10S to the front side of the chassis13.

Each of the mounting direction of the discharge tubes15to the relay connectors14and the mounting direction of the power boards16to the relay connectors14is set to be substantially perpendicular to the surface of the chassis13. Therefore, the discharge tubes15and the power boards16can be mounted to the chassis13so as to form a stack structure. The stackability enables the assembling to be performed by an automatic machine.

Next, preferred embodiment 2 of the present invention will be explained with reference toFIGS. 10 to 21. In the present preferred embodiment 2, the construction of a lighting device110differs from that of preferred embodiment 1. The other constructions are similar to 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 Lighting Device110

The lighting device110includes a lamp unit112and power boards116, as shown inFIGS. 10,11and21. The lamp unit112includes a metallic chassis113, which preferably has a substantially horizontally-elongated rectangular plate shape and functions as a reflector plate. Further included are a plurality of discharge tubes115held in a horizontal position and vertically arranged on the front side of the chassis113so as to be parallel or substantially parallel to one another, and a plurality of relay connectors114which are vertically arranged along the lateral edges of the chassis113so as to correspond to the discharge tubes115. The power boards116are disposed on the back side of the chassis113so as to supply power to the discharge tubes115via the relay connectors114.

A plurality of substantially rectangular mounting holes113H corresponding to the ends of the discharge tubes115are formed through the chassis113so as to extend from the front side to the back side, and are vertically arranged to be level with the respective discharge tubes115(SeeFIGS. 15 and 16). The relay connectors114are mounted through the respective mounting holes113H.

As shown inFIGS. 12 to 16, each relay connector114includes a holder120made of synthetic resin, and a relay terminal131that is housed in the holder120and made of metal (e.g., stainless steel).

The holder120includes a box-shaped portion121that has a block-shape configuration as a whole, and further includes a wall portion122that projects backward from the back surface of the box-shaped portion121.

A container room123is formed in the box-shaped portion121, 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 chassis113). The front opening portion of the opening of the container room123is provided as a receiving opening124, into which an end portion (or ferrule136) of the discharge tube115is fitted from the front side. The lateral opening portion is provided as an escape opening125for preventing interference with the glass tube134when the end portion of the discharge tube115is held in the container room123. A stopper126is formed on the escape opening125, so as to bulge inward from the opening edge and form a plate-shaped configuration. Due to the stopper126, the escape opening125is narrowed so as to form a substantially U-shaped opening. The vertical size of the substantially U-shaped escape opening125is set to be smaller than the inner diameter of the body137of the ferrule136and be equal to or slightly larger than the outer diameter of the glass tube134of the discharge tube115. On the escape opening125, a concave portion127having a semicircular shape is formed on the far end portion of the opening edge. The radius of curvature of the concave portion127is set to be equal to or slightly larger than the radius of curvature of the outer circumference of the glass tube134. On the escape opening125, a pair of upper and lower guiding portions128are formed on areas of the opening edge on the front side of the concave portion127.

On the box-shaped portion121, an extended portion129extending parallel or substantially parallel to the chassis113is formed on the lateral surface of the box-shaped portion121that includes the escape opening125. The extended portion129extends so as to separate the front surface of the chassis113from the escape opening125. A pair of upper and lower retaining protrusions130are formed on the outer surface (i.e., upper surface and lower surface) of the box-shaped portion121.

The relay terminal131is held within the holder120. The relay terminal131can be formed by bending a metallic plate that is formed into a predetermined shape by punching, for example. The relay terminal131includes a pair of vertically symmetrical elastic pressing portions132formed of curved plates, and further includes a board connecting portion133formed as a flat plate-shaped portion that projects to the back side. The pair of elastic pressing portions132, which are housed in the container room123, can deflect elastically and vertically so as to increase distance therebetween. The vertical distance between the elastic pressing portions132is shortest at a position corresponding to the front side of the concave portion127of the stopper126. The minimum distance between the elastic pressing portions132, when elastic pressing portions132are not forced into elastic deflection or are in a free state, is set to be smaller than the outer diameter of the body137of the ferrule136attached on the discharge tube115. On the other hand, the board connecting portion133projects from the back surface of the box-shaped portion121so as to be exposed to the outside of the holder120, and extends backwards along the wall portion122.

When the relay connector114is mounted to the chassis113, the wall portion122of the holder120is inserted into a mounting hole113H from the front side of the chassis113. Thereby, the outer surface of the box-shaped portion121comes in contact with the opening edge of the mounting hole113H on the front surface of the chassis113, while the retaining protrusions130are locked by the opening edge of the mounting hole113H on the back surface of the chassis113. Thus, the chassis113is sandwiched between the outer surface of the box-shaped portion121on the front side and the retaining protrusions130on the back side. Thereby, the holder120is fixed to the chassis113so that its movement in the mounting direction (i.e., the through direction of the mounting hole113H) is restricted. Then, the mounting of the relay connector114to the chassis113is completed. When the relay connector114is attached to the chassis113, the box-shaped portion121as the front end portion of the holder120projects (or is exposed) to the front side of the chassis113while the wall portion122as the back end portion of the holder120projects (or is exposed) to the back side of the chassis113.

Referring toFIG. 17, each discharge tube115preferably is a cold cathode fluorescent tube that includes a generally elongated straight glass tube134having a circular cross section, and elongated metallic (e.g., nickel or cobalt metal) outer leads135which have a circular cross section and project linearly from the respective ends of the glass tube134and coaxially with the glass tube134. Further included are ferrules136attached to the respective end portions of the glass tube134. Mercury is encapsulated in the glass tube134. Each end portion of the glass tube134is melted into a substantially hemispherical shape by heat, and thereby forms a domed portion. The outer lead135penetrates the domed portion.

Referring toFIGS. 18 to 20, each ferrule136preferably 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, for example. The ferrule136includes a body137and a conductive portion140. The body137preferably has a substantially cylindrical shape concentric with the glass tube134. The inner diameter of the body137preferably is slightly larger than the outer diameter of the glass tube134.

Three pairs of elastic gripping portions138A,138B are formed on the body137by making slit-shaped cuts in portions thereof, which are arranged at even angular intervals along the circumferential direction.

A first elastic gripping portion138A, i.e., one of a pair of elastic gripping portions138A,138B, 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 portion139is formed on the distal end portion (or posterior end portion) of the first elastic gripping portion138A, so as to curve in an oblique direction leaning radially outwardly. The outer surface of the curve (or inwardly facing surface) of the curved portion139is provided as a contact point when abutting on the outer circumferential surface of the glass tube134. The imaginary line that connects the contact points provided on the three first elastic gripping portions138A forms a circle concentric with the body137. The diameter of the imaginary circle, when the first elastic gripping portions138A are not forced into elastic deflection or in a free state, preferably is smaller than the outer diameter of the glass tube134.

A second elastic gripping portion138B, i.e., the other of the pair of elastic gripping portions138A,138B, is arranged circumferentially adjacent to the first elastic gripping portion138A, and is generally formed as a cantilevered portion extending anteriorly or reversely from the first elastic gripping portion138A (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 portion138B is provided as a contact point when abutting on the outer circumferential surface of the glass tube134. The imaginary line that connects the contact points provided on the three second elastic gripping portions138B forms a circle concentric with the body137. The diameter of the imaginary circle, when the second elastic gripping portions138B are not forced into elastic deflection or are in a free state, is set to be smaller than the outer diameter of the glass tube134.

On the body137, 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 body137so as to be flush therewith. The conductive portion140is provided as a cantilevered portion that extends anteriorly from between the pair of protector portions. The conductive portion140includes a long portion141continuous with the anterior end of the body137, and a cylindrical portion142that further projects anteriorly from the anterior end (or distal end) of the long portion141.

The long portion141includes a proximal portion141athat extends from the body137so as to be flush with the body137and parallel to the axis thereof, and further includes an intermediate portion141bthat extends radially inwardly from the distal end of the proximal portion141atoward the axis of the body137. Further included is a distal portion141cthat extends from the distal end of the intermediate portion141band parallel or substantially parallel to the axis of the body137. The cylindrical portion142is connected to the distal end of the distal portion141c. The width of the long portion141is set to be sufficiently small for the length of the long portion141. Therefore, the long portion141is capable of elastic deformation in the radial direction of the body137, elastic deformation in a direction intersecting with the radial direction (and intersecting with the longitudinal direction of the long portion141), and elastic torsional deformation around the long portion141itself as the axis.

The cylindrical portion142, which can be formed by bending a portion laterally extending from the distal end of the long portion141into a cylindrical shape, is arranged substantially coaxially with the body137. The cylindrical portion142is capable of displacement around the axis of the ferrule136and radial displacement, due to elastic deflection of the long portion141.

Attachment of Ferrule136to Glass Tube134

Next, an assembling process for attaching a ferrule136to a glass tube134will be explained.

During the assembling process, while a ferrule136and a glass tube134are held by respective holding devices (not shown), the ferrule136and the glass tube134are moved relatively and coaxially so as to approach each other. Thereby, the body137is fitted onto the glass tube134. When the body137begins engagement, the contact points provided on the distal end portions of the three pairs of elastic gripping portions138A,138B have elastic contact with the outer circumference of the glass tube134. The contact points slide on the outer circumferential surface of the glass tube134, as the assembling process proceeds. Then, the tip of the outer lead135having passed through the body137begins to enter the hollow of the cylindrical portion142. When both of the holding devices have thereafter reached predetermined final positions, the ferrule136and the glass tube134are axially positioned in proper positions, resulting in the tip end portion of the outer lead135circumferentially surrounded by the cylindrical portion142. At the time, the tip end portion of the outer lead135will not greatly protrude from the anterior end of the cylindrical portion142. That is, it slightly protrudes out of the cylindrical portion142, or is aligned with the anterior end of the cylindrical portion142, or alternatively it is located within the cylindrical portion142.

Thereafter, the cylindrical portion142is clamped so as to deform with diameter reduction. After being clamped, the cylindrical portion142is electrically conductively fixed to the outer lead135by welding, and consequently the ferrule136is integrated with the glass tube134. Then, the assembling process terminates, and the discharge tube115is completed.

When the ferrule136is attached to the glass tube134, the body137is concentrically held on the glass tube134due to the elastic holding function of the three pairs of elastic gripping portions138A,138B. A gap (airspace) is secured between the outer circumference of the glass tube134and the inner circumference of the body137, so as to extend over the substantially entire circumference.

Instead of the cylindrical portion142, a U-shaped connecting portion142amay be provided as shown inFIGS. 29 and 30. In this case, after a glass tube134is fitted into a ferrule136, the U-shaped connecting portion142ais bended so as to hug the outer lead135, in order to achieve electrical connection between the outer lead135and the connecting portion142a. According to the present preferred embodiment thus including the bendable U-shaped connecting portion142a, electrical connectivity with the outer lead135can be further improved.

Mounting of Discharge Tube115to Relay Connectors114

The discharge tube115, thus assembled, is fixed to relay connectors114. At the time of fixation, the discharge tube115held in a horizontal position is moved toward the front surface of the chassis113, and the end portions and the ferrules136of the glass tube134are fitted into the container rooms123of the relay connectors114from the front side. At the time, the pair of elastic pressing portions132are pushed by the body137of the ferrule136so as to open vertically due to elastic deflection. After the body137has passed through the shortest-distance portions of the pair of elastic pressing portions132, the body137is pulled deep into the container room123due to elastic restoring forces of the elastic pressing portions132, resulting in the body137abutting on the bottom of the container room123. Then, the mounting of the discharge tube115is completed.

The discharge tube115thus mounted is held by the pairs of elastic pressing portions132at its end portions, and consequently is fixed to the chassis113via the relay terminals131and the holders120provided as the relay terminal131mounting bases. At the time, the weight of the discharge tube115is received solely by the chassis113via the relay connectors114. That is, the outer leads135will not be under load due to the weight of the discharge tube115.

The pair of elastic pressing portions132can have elastic contact with the outer circumferential surface of the body137, and thereby the outer lead135is electrically conductively connected to the relay terminal131via the ferrule136. Further, the glass tube134is held due to elastic restoring forces of the pair of elastic pressing portions132, so as to be pressed against the concave portion127of the stopper126. Therefore, when viewed along the axial direction of the discharge tube115, the body137appears to be positioned so as to partially overlap with the stopper126. That is, the end edge of the body137on the opposite side of the conductive portion140is axially positioned in proximity to the stopper126so as to be partially faced therewith.

The extended portion129is provided on the outer surface of the holder120, which is perpendicular or substantially perpendicular to the surface of the chassis113and includes the escape opening125of the container room123, so as to protrude from between the chassis113and the escape opening125and extend along the surface of the chassis113. This results in a long creepage distance from the inside of the container room123to the front surface of the chassis113. Thereby, a leak, from the discharge tube115held in the container room123to the chassis113outside the holder120, can be prevented.

Overview of Power Board116

As shown inFIG. 21, each power board116includes a circuit board117having a circuit disposed on its back surface (i.e., the surface on the opposite side of the chassis113), electronic components119mounted on the back surface of the circuit board117, and a plurality of on-board connectors118mounted on the back surface of the circuit board117.

The circuit board117preferably has a substantially 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 holes117H having a vertically-elongated rectangular shape are formed through the circuit board117so as to extend from the front side to the back side. The plurality of fitting holes117H are arranged vertically along the lateral side edge of the circuit board117so as to correspond to the above-described relay terminals131(or relay connectors114). Each on-board connector118includes 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 connectors118are arranged along the lateral side edge of the circuit board117so as to correspond to the respective fitting holes117H. A fitting space (not shown) is formed on the outer surface of the housing so as to correspond to the fitting hole117H, and the output terminal is partly exposed to the fitting space.

While the circuit board117is kept parallel to the chassis113, the power board116is moved toward the chassis113from the back side and is fixed thereto. At the time of fixation, the wall portions122of the relay connectors114and the board connecting portions133arranged along the wall portions122penetrate the circuit board117through the fitting holes117H and are inserted into the fitting spaces of the on-board connectors118. Thereby, the on-board connectors118are fitted onto the relay connectors114, and the output terminals are conductively connected to the relay terminals131.

Operational Effects of Preferred Embodiment 2

In preferred embodiment 2, when a discharge tube115is supported on relay connectors114, the stoppers126lock the ferrules136. Therefore, the discharge tube115is secure from axial movement relative to the relay connectors114. That is, if a force is applied to the discharge tube115so as to cause movement to the right, the stopper126catches the left-adjacent ferrule136attached on the left end portion of the discharge tube115so that the movement of the discharge tube115to the right is restricted. If a force is applied to the discharge tube115so as to cause movement to the left, the stopper126catches the right-adjacent ferrule136attached on the right end portion of the discharge tube115so that the movement of the discharge tube115to the left is restricted. Thus, the axial movement of the discharge tube115to either right or left is restricted, and therefore the tip of the outer lead135is reliably prevented from hitting the wall of the container room123on the opposite side of the escape opening125.

The stopper126can engage with and lock the end edge of the ferrule136, and therefore a hole that can engage with the stopper126is not required to be formed on the outer circumference of the ferrule136. Thereby, processing cost can be reduced, and reduction in strength of the ferrule136can be prevented.

In the case of a construction in which a stopper126can engage with the end edge of a ferrule136on the side of the conductive portion140, the conductive portion140extending from the end edge of the ferrule136may preclude the end edge of the ferrule136from engaging with the stopper126, when the ferrule136is attached at some angle about its axis. However, in the present preferred embodiment 2, the stopper126is arranged to engage with the end edge on the opposite side of the conductive portion140. Therefore, the conductive portion140will not preclude the ferrule136from engaging with the stopper126, and consequently the ferrule136can infallibly engage with the stopper126.

The conductive portion140includes a cylindrical portion142, which can be circumferentially connected to the outer lead135so as to surround it. Thereby, the conductive portion140can be prevented from disengaging from the outer lead135. That is, the cylindrical portion142will not disengage from the outer lead135when the cylindrical portion142is clamped. Therefore, the conductive portion140can be infallibly connected to the outer lead135.

The margin for engagement of a ferrule136with a stopper126corresponds to half of the dimensional difference between the outer diameters of the glass tube134and the ferrule136. In preferred embodiment 2, ferrules136are concentrically held on a glass tube134due to the elastic gripping portions138A,138B. Therefore, if the ferrule136is set to be large, a large dimensional difference can be secured between the inner diameter thereof and the outer diameter of the glass tube134. Thereby, the margin for engagement of the ferrule136with the stopper126can be increased, resulting in reliable restriction of movement of the discharge tube115.

The concave portion127is formed on a stopper126, so as to abut on the outer circumference of a glass tube134when the ferrule136engages with the stopper126. Further, the pair of elastic pressing portions132capable of pressing the discharge tube115toward the concave portion127side are provided in the relay connector114. Specifically, the pair of elastic pressing portions132press the discharge tube115toward the concave portion127side, obliquely from above and obliquely from below, i.e., vertically symmetrically. Thereby, the glass tube134is prevented from disengaging from the concave portion127, and therefore the engagement of the ferrule136with the stopper126can be reliably maintained.

The relay connector114is formed by mounting a relay terminal131in a holder120made of synthetic resin. In the present preferred embodiment 2, the stopper126is formed on the synthetic-resin holder120. Therefore, a stopper is not required to be formed on the relay terminal131, and thereby the material for manufacturing the relay terminals131can be reduced. Considering that the material cost for synthetic resin is generally lower than that for metal, the material cost for relay connectors114can be reduced according to preferred embodiment 2.

Next, preferred embodiment 3 of the present invention will be explained with reference toFIGS. 22 to 28. In the present preferred embodiment 3, the constructions for supporting a discharge tube115differ from those of preferred embodiment 2. The other constructions are similar to preferred embodiment 2. Therefore, the same constructions are designated by the same symbols, and explanations for the constructions, operations and effects thereof are omitted.

Overview of Grounding Member150

In preferred embodiment 2, the end portions of a discharge tube115are supported by relay connectors114, each of which includes a holder120and a relay terminal131. In the present preferred embodiment 3, as shown inFIGS. 22 and 23, one of the end portions of a discharge tube115is supported by the same relay connector114as preferred embodiment 2, while the other end portion of the discharge tube115is supported by a grounding member150.

As shown inFIG. 25, the grounding member150includes an elongated support plate151fixed to the chassis113so as to be along one of the lateral edge portions thereof, and further includes a plurality of grounding terminals152conductively mounted on the front surface of the support plate151. Mounting holes151H are formed through the support plate151so as to correspond three-to-one with the grounding terminals152. The support plate151is formed of a substrate or a metallic plate.

On the other hand, as shown inFIGS. 26 and 27, each grounding terminal152, which can be formed by bending a metallic (e.g., nickel silver) plate that is formed into a predetermined shape by punching, includes abase portion153and a pair of elastic pressing portions154which extend vertically symmetrically from the respective upper and lower edge portions of the base portion153to the front side. Further included is a stopper155that extends from one of the lateral edge portions of the base portion153to the front side.

The pair of elastic pressing portions154are provided on the lateral edge portion on the opposite side of the stopper155, so as to form bulging curves toward each other. The elastic pressing portions154are capable of elastic deflection so as to increase the distance therebetween. The minimum distance between the pair of elastic pressing portions154, when the elastic pressing portions154are free from elastic deflection, is set to be smaller than the outer diameter of the glass tube134of a discharge tube115.

The stopper155is raised from the base portion153, so as to form a right angle with the axis of the discharge tube115. A concave portion156is formed on the stopper155, so as to sag in a substantially circular arc. On a relay connector114of the embodiment 2, a pair of guiding portions128protrude from the respective upper and lower sides of the concave portion127of the stopper126. However, in preferred embodiment 3, the heights of portions protruding from the respective upper and lower sides of the concave portion156of the base portion153are reduced to be short. That is, structure or elements corresponding the guiding portions128of preferred embodiment 2 are not provided. Therefore, metallic material required for grounding terminals152can be reduced, compared to including guiding portions.

Three leg portions157are further formed on the base portion153, so as to be integrated therewith. Two of the three leg portions157are provided between the elastic pressing portions154and the stopper155, so as to project from the respective upper and lower edge portions of the base portion153to the opposite side of the elastic pressing portions154or the stopper155(i.e., to the back side). The remaining one of the leg portions157is provided on the lateral edge of the base portion153on the opposite side of the stopper155, so as to project from the intermediate position between the elastic pressing portions154to the opposite side of the elastic pressing portions154or the stopper155(i.e., to the back side).

The grounding terminal152is not housed in a member such as a plastic housing, i.e., barely provided, and is conductively fixed to the support plate151by soldering or the like so that its leg portions157penetrate through the mounting holes151H (SeeFIG. 28). Thus, the plurality of grounding terminals152are mounted to the common support plate151, and thereby are conductively connected to one another via the support plate151. Power boards are not connected to the grounding members150, and the support plate151is conductively connected to the chassis.

Mounting of Discharge Tube115to Grounding Terminal152

When a discharge tube115is fixed to a grounding terminal152, the discharge tube115held in a horizontal position is moved toward the front surface of the chassis113, and the end portion and the ferrule136of the glass tube134are fitted between the pair of upper and lower elastic pressing portions154from the front side. At the time, the pair of elastic pressing portions154are pushed by the body137of the ferrule136so as to open vertically due to elastic deflection. After the body137has passed through the shortest-distance portions of the pair of elastic pressing portions154, the body137is pulled toward the base portion153side due to elastic restoring forces of the elastic pressing portions154, resulting in the body137abutting on the base portion153. Then, the fixation of the discharge tube115is completed. The other end portion of the discharge tube115is fixed to a relay connector114in a similar manner to preferred embodiment 2.

The discharge tube115thus mounted is supported by the relay connector114and the grounding member150at its respective end portions. The pairs of elastic pressing portions132,154can have elastic contact with the outer circumferential surfaces of the bodies137of the ferrules136, and thereby the outer leads135are electrically conductively connected to the relay terminal131and the grounding terminal152via the ferrules136. Further, the glass tube134is held due to elastic restoring forces of the pairs of elastic pressing portions132,154, so as to be pressed against the concave portions127,156of the stoppers126,155. Therefore, when viewed along the axial direction of the discharge tube115, the body137appears to be positioned so as to partially overlap with the stopper126or155. That is, the end edge of the body137on the opposite side of the conductive portion140is axially positioned in proximity to the stopper126or155so as to be partially faced therewith.

As shown inFIGS. 31 and 32, protector portions551may be provided on the grounding terminal152. Each protector portion551includes a restricting portion552for an elastic pressing portion, and further includes an abutting portion553for abutting on the support plate. When the grounding terminal152is mounted and fixed to the support plate151, the abutting portions553abut on or are located close to the support plate151. If some kind of external force is applied to the elastic pressing portions154so that they are pushed to open, they first come in contact with the restricting portions552during the course of opening. The abutting portions553serve as supports for preventing the protector portions551from collapsing, when an additional load is thereafter applied. The protector portions551are connected to the feet of the elastic pressing portions154, and therefore the abutting portions553should be arranged lateral to the connection portion in order that the abutting portions553work. Note that abutting portions553located at a longer distance from the connection portion are more effective.

Operational Effects of Preferred Embodiment 3

In preferred embodiment 3, when a discharge tube115is supported on a relay connector114and a grounding member150, the stopper126of the holder120and the stopper155of the grounding terminal152lock the ferrules136on the respective ends of the discharge tube115. Therefore, the discharge tube115is secure from axial movement relative to the relay connector114.

That is, if a force is applied to the discharge tube115so as to cause movement from the relay connector114side to the grounding member150side, the ferrule136attached on the end portion of the discharge tube115on the relay connector114side is caught by the stopper126of the holder120so that the movement of the discharge tube115to the grounding member150side is restricted. If a force is applied to the discharge tube115so as to cause movement from the grounding member150side to the relay connector114side, the ferrule136attached on the end portion of the discharge tube115on the grounding member150side is caught by the stopper155of the grounding terminal152so that the movement of the discharge tube115to the relay connector114side is restricted. Thus, the axial movement of the discharge tube115to either right or left is restricted, and therefore the tip of the outer lead135is secure from hitting the wall of the container room123on the opposite side of the escape opening125or hitting the sidewall of the chassis113.

The concave portion156is formed on the stopper155of a grounding terminal152, so as to abut on the outer circumference of a glass tube134when the ferrule136is engaged with the stopper155. Further, the pair of elastic pressing portions154capable of pressing the discharge tube115toward the concave portion156side are provided on the grounding terminal152. Specifically, the pair of elastic pressing portions154press the discharge tube115toward the concave portion156side, obliquely from above and obliquely from below, i.e., vertically symmetrically. Thereby, the glass tube134is prevented from disengaging from the concave portion156, and therefore the engagement of the ferrule136with the stopper155can be reliably maintained.

On the grounding member150, the stoppers155are integrated with the respective grounding terminals152provided to achieve conductive connection to the ferrules136. Thereby, the number of components can be reduced in preferred embodiment 3, 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 explained in the above description made with reference to the drawings. The following preferred embodiments may be included in the technical scope of the present invention, for example.

The mounting direction of the discharge tube to the relay connectors may differ from the mounting direction of the relay connectors to the connector portions. For example, the mounting direction of the discharge tube to the relay connectors may be substantially parallel to the surface of the chassis, while the mounting direction of the relay connectors to the connector portions is substantially perpendicular to the surface of the chassis. Conversely, the mounting direction of the relay connectors to the connector portions may be substantially parallel to the surface of the chassis, while the mounting direction of the discharge tube to the relay connectors is substantially perpendicular to the surface of the chassis.

The chassis when mounted to the lighting jig is not limited to being held in a horizontal position, but rather may be slanted at an acute angle to the horizontal plane or form a right angle with the horizontal plane.

In the above preferred embodiments, the lamp unit, in which the relay connectors and the discharge tubes are mounted to the chassis, is preferably assembled ahead of fixation to the lighting jig, and is fixed to the lighting jig. However, the construction to be fixed to the lighting jig is not limited to the lamp unit. The chassis, to which the relay connectors are mounted but the discharge tubes are not mounted, may be fixed to the lighting jig, so that the discharge tubes are thereafter mounted.

The connecting portion provided on the relay connector for connection to the 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 the relay connectors, and the connecting portion provided on the connector portion for connection to the relay connector should be formed as protrusions.

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 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.