JP2010086910A - Illumination device for flat display, flat display, and television receiving set - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain desired light-emitting characteristics as an illumination device even if a discharge tube having anisotropy in the axial direction in the light-emitting characteristics is used. <P>SOLUTION: By aligning a plurality of cold-cathode tubes in which lead terminals are protruded from both ends of a glass tube in a chassis, the illumination device for a flat display is constituted. In respective cold-cathode tubes, at the primary sealing side end part of the glass tube and at its opposite secondary sealing side end part, the lengths of the lead terminals are made to be different, and in the respective cold-cathode tubes, the lead terminals different in lengths are arranged to be positioned alternately at respectively prescribed numbers along a juxtaposed direction of the cold-cathode tubes. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an illumination device for a flat display device, a flat display device, and a television receiver.

  Conventionally, a liquid crystal display device is well known as a kind of flat display device, and a discharge tube such as a cold cathode tube is used in a backlight device as an illuminating device. The general manufacturing method of the backlight device will be briefly described. First, a cold-cathode tube is manufactured by a lamp manufacturer, and subsequently connected to the inverter board with respect to lead terminals formed at both ends of the cold-cathode tube. Solder the harness to be used, package it, and deliver it to the backlight device manufacturer or the liquid crystal display device manufacturer. A backlight device manufacturer or a liquid crystal display device manufacturer assembles a component such as a cold-cathode tube into the backlight device chassis and inserts the connector of the harness into the inverter board to complete the backlight device.

  In the manufacturing method described above, the work of soldering the harness to the lead terminal of the cold cathode tube and the work of inserting the connector of the harness are required, so that the work time and cost are likely to increase. In view of this, there is one disclosed in Patent Document 1 below as an example of a configuration for connecting to a cold cathode tube using a connector in order to omit the soldering operation to the cold cathode tube.

  In the structure disclosed in this document, a connector in which a pair of elastic contact pieces are arranged opposite to each other in a connector housing is arranged in advance in a chassis, and a lead wire of a cold cathode tube is pushed into the connector to make electrical connection and cooling. The cathode tube end is held. In this way, it is not necessary to perform soldering directly on the cold cathode tube.

On the other hand, the method described in Patent Document 2 below is known as a method for manufacturing a cold cathode tube. In this case, the cylindrical glass tube with both ends opened is placed upright, the solution in which the fluorescent material is dispersed is sucked and introduced from the opening on the lower end side, and the solution is dropped when sucked up to the entire glass tube By doing so, the fluorescent material is adhered to the inner peripheral surface of the glass tube. Thereafter, an electrode is first set and sealed (primary sealing) in the opening (lower end) of the glass tube where the fluorescent material is introduced, and then the electrode is set in the other opening and sealed ( Cold cathode tubes are manufactured by secondary sealing.
JP 2007-95671 A Japanese Patent Laid-Open No. 9-17329

  When such a long discharge tube is manufactured, anisotropy in the axial direction may occur in the light emission characteristics of the discharge tube for some reason in the manufacturing process. For example, the fluorescent material includes a plurality of types of fluorescent material particles corresponding to the emission color, and the particle size and specific gravity of the fluorescent material particles are different for each type. In the case of adopting a manufacturing method in which the fluorescent material is adhered to the inside of the glass tube by utilizing an axial bias in the distribution of the various fluorescent material particles, as a result, the emission characteristics of the cold cathode tube have an axial anisotropy, That is, color unevenness in the axial direction may occur.

  In view of such circumstances, in the case where a plurality of cold-cathode tubes are installed in parallel, such as a direct-type backlight device, the backlight device can be changed by alternately changing the mounting directions of adjacent cold-cathode tubes. It can be considered that color unevenness hardly occurs as a whole. Here, in the conventional type in which the harness is soldered to the cold cathode tube, the lamp manufacturer takes over the cold cathode tube production line and performs the soldering operation as it is. It may be possible to relatively easily perform the operation of alternately changing the direction of the cold cathode tubes by utilizing the fact that the directions of the cathode tubes are aligned.

  However, if a configuration in which a cold cathode tube is connected using a connector is adopted, the cold cathode tube is assembled to the chassis in a backlight device manufacturer or a liquid crystal display manufacturer instead of a lamp manufacturer. For this reason, when the cold cathode tube group is to be arranged in a specific direction (for example, it is alternately changed), the cold cathode tube itself is discriminated to determine the direction or the assembled cold cathode tube group is seen. We face the problem of not being able to determine whether their orientation is appropriate or not.

  The present invention has been completed based on the above-described circumstances, and it is possible to easily know the direction of the discharge tube, and to obtain desired light emission characteristics as the entire lighting device, An object is to provide a flat display device and a television receiver.

  The illumination device for a flat display device of the present invention includes a plurality of discharge tubes in which both ends of a glass tube are sealed, and lead terminals are projected from the sealed end portions, and the light emission characteristics have axial anisotropy. The discharge tube includes a chassis that holds the discharge tubes in parallel. In the discharge tube, a lead terminal on one end side and a lead terminal on the other end side are different in length, and the discharge tube Is characterized in that the lead terminals having different lengths are arranged in a predetermined direction.

  When the discharge tube is configured as described above, the direction of the discharge tube can be confirmed by looking at the lead terminal itself of the discharge tube. For this reason, it becomes possible to arrange | position a discharge tube in a desired direction, and can obtain a desired light emission characteristic as an illuminating device for flat display apparatuses. For example, in order to cancel the light emission characteristics of the discharge tube that has anisotropy in the axial direction, when it is arranged alternately every predetermined number, or when it is intended to obtain the desired light emission characteristics in the lighting device by utilizing the light emission characteristics In addition, the arrangement direction of the plurality of discharge tubes can be determined depending on the length of the lead terminal of each discharge tube.

  In this case, when the tolerance of the processing dimension of the glass tube is x and the tolerance of the processing dimension of the lead terminal is y, the length dimension difference ΔL between the pair of lead terminals is set to satisfy ΔL> (x + y). Thus, the specific direction of the discharge tube can be surely visually confirmed. In addition, "the processing dimension of a glass tube" means here the dimension between the sealing edge parts of both sides in the case of manufacturing as a discharge tube by sealing both ends of a glass tube. Further, the “process dimension of the lead terminal” refers to the length dimension of the lead wire itself protruding from the sealed end of the glass tube.

  In order to suppress the occurrence of peculiarities depending on the location of the light emission characteristics of the flat panel display lighting device, the predetermined number is most preferably one.

  In view of the cause of the axial anisotropy of the light emission characteristics of the discharge tube, the discharge tube introduces a fluorescent material from one end of the glass tube having openings at both ends, and the inner surface of the glass tube. After the fluorescent material is attached to the glass tube, the discharge lead terminal projects from the both ends of the glass tube to the outside, and is manufactured by sealing both ends of the glass tube. Can be dealt with.

  In addition, after the discharge tube introduces the fluorescent material from one end of the glass tube having openings at both ends and adheres the fluorescent material to the inner surface of the glass tube, the lower end side of the glass tube is primarily sealed, Even when the opposite side is produced by secondary sealing, the light emission characteristics often have anisotropy in the axial direction. Therefore, the present invention is more effective when such a discharge tube is used. It is.

As an embodiment according to the illumination device for a flat display device of the present invention, the following configuration is preferable.
(1) The chassis is provided with a connector corresponding to each end of the discharge tube, and the lead terminal of the discharge tube is pushed into the connector from a side facing the chassis. The terminal metal fitting which contacts is provided. Thereby, the lead terminal of the discharge tube is pushed into the connector, so that it can be connected to the lead terminal of the discharge tube, and the assembling workability of the lighting device is excellent.
(2) It is preferable that the said terminal metal fitting is comprised with a pair of elastic contact piece mutually arrange | positioned so that the opposite side to the said chassis may be opened. Thus, the lead terminal can be connected to the terminal fitting by simply pushing the lead terminal into the connector from above, and the protruding length of the lead terminal can be clearly confirmed.
(3) It is preferable that the connector is provided with a positioning portion in which a sealing end portion of the glass tube of the discharge tube contacts in the axial direction to perform positioning. By applying the sealing end to the positioning portion, the position of the discharge tube can be made uniform, and as a result, the difference in the protruding length of the lead terminal can be clearly confirmed.
(4) Further, in the pair of connectors that hold the cold cathode tube at both ends, the distance between the positioning wall portions is equal to the distance between the sealed end portions of the glass tube of the cold cathode tube. It is preferable to arrange them so as to be a value obtained by adding a dimension difference ΔL. By doing so, the dimensions of the connector from the positioning wall portion to the front side of the lead terminal are equal at both ends of the cold cathode tube, so that it is possible to design the connectors on both sides of the cold cathode tube in common. Also, if each cold cathode tube is always set with the sealed end of the shorter lead terminal in contact with the positioning wall of the connector, the position of the tip of each lead terminal will be On the other hand, the position of the glass tube of the cold cathode tube is shifted by ΔL according to the direction of the cold cathode tube. As a result, when setting the cold cathode tube while changing the direction regularly, it becomes easy to find a setting error in that direction.

  A flat display device of the present invention includes the above-described flat display device illumination device, and a display panel that performs display using light having the light source as a light source.

  According to such a flat display device, the flat display device illumination device that supplies light to the display panel has less specificity depending on the location of light emission characteristics such as color unevenness, so that display with excellent display quality is possible. Can be realized.

  An example of the display panel is a liquid crystal panel. Such a flat display device can be applied as a liquid crystal display device to various uses such as a display of a television or a personal computer, and is particularly suitable for a large screen.

  According to the present invention, since the direction can be easily confirmed with the discharge tube itself, it is possible to provide an illumination device for a flat display device with less specificity depending on the location of the light emission characteristics.

<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIGS. In this embodiment, the liquid crystal display device 10 is illustrated. A part of each drawing shows an X-axis, a Y-axis, and a Z-axis, and each axis is drawn so as to be the direction shown in each drawing. Moreover, let the upper side shown in FIG.2 and FIG.3 be a front side, and let the lower side shown in FIG.2 and FIG.3 be a back side.

  As shown in FIG. 1, the television receiver TV according to the present embodiment includes a liquid crystal display device 10 (a flat display device), front and back cabinets Ca and Cb that are accommodated so as to sandwich the liquid crystal display device 10, and a power supply substrate P. And a tuner substrate T. The liquid crystal display device 10 has a horizontally long rectangular shape as a whole, and includes a liquid crystal panel 11 as a display panel and a backlight device 12 (illumination device for a flat display device) as an external light source, as shown in FIG. These are integrally held by a bezel 13 or the like having a square frame shape.

  Next, the liquid crystal panel 11 and the backlight device 12 constituting the liquid crystal display device 10 will be described sequentially. The liquid crystal panel 11 has a rectangular shape in plan view, and as shown in FIG. 3, a pair of glass substrates 11a and 11b are bonded together with a predetermined gap therebetween, and between the glass substrates 11a and 11b. A liquid crystal layer (not shown) is enclosed. One glass substrate 11a is provided with a switching element (for example, TFT) connected to a source wiring and a gate wiring orthogonal to each other, a pixel electrode connected to the switching element, an alignment film, and the like. The glass substrate 11b is provided with a color filter in which colored portions such as R (red), G (green), and B (blue) are arranged in a predetermined arrangement, a counter electrode, and an alignment film. Among these, image data and various control signals necessary for displaying an image from a drive circuit substrate (not shown) are supplied to the source wiring, the gate wiring, the counter electrode, and the like. In addition, polarizing plates 11c and 11d are disposed outside the glass substrates 11a and 11b, respectively.

  As shown in FIGS. 2 and 3, the backlight device 12 is a so-called direct-type backlight device in which a light source is disposed directly under the back surface of the liquid crystal panel 11, and is a front side (light emitting side, liquid crystal panel 11 side). A substantially box-shaped chassis 14 that is open to the top of the chassis 14, a reflection sheet 15 laid in the chassis 14, a plurality of optical members 16 that are attached so as to cover the openings of the chassis 14, and the optical members 16 are held. A possible frame 17, a cold cathode tube 18 that is a plurality of discharge tubes accommodated in parallel in the chassis 14, and each end of the cold cathode tube 18 is shielded from light and itself has light reflectivity. And a lamp clip 20 that holds the central portion of the cold cathode tube 18. Further, the backlight device 12 includes an inverter board 21 (power circuit board) disposed on the back side of the chassis 14, a connector 22 for electrically connecting the inverter board 21 and the cold cathode tube 18, and a connector 22. And a holding member 23 for attaching to the chassis 14.

  The chassis 14 is made of metal such as aluminum, and has a configuration in which a side plate rises from an outer peripheral end of a bottom plate 14 a having a rectangular shape in plan view like the liquid crystal panel 11. The bottom plate 14a is located on the back side of the cold cathode tube 18, and its long side direction coincides with the X-axis direction of each drawing, and its short side direction coincides with the Y-axis direction. The reflection sheet 15 is made of a synthetic resin exhibiting white with excellent light reflectivity and is laid so as to cover almost the entire inner surface of the chassis 14, and transmits light from the cold cathode tube 18 to the optical member 16 side. It has a function of reflecting to the (light emitting side).

  The optical member 16 has a rectangular shape in plan view like the bottom plate 14a of the chassis 14 and the liquid crystal panel 11, is made of a synthetic resin having translucency, and has a cold cathode tube 18 on the back side and a liquid crystal panel 11 on the front side. Intervene between. The optical member 16 is composed of, for example, a diffusion plate, a diffusion sheet, a lens sheet, and a brightness enhancement sheet in order from the back side, and emits light emitted from each cold cathode tube 18 that is a linear light source with uniform planar light. It has functions such as converting to.

  The frame 17 has a frame shape along the outer peripheral edge of the liquid crystal panel 11 or the optical member 16. The frame 17 is arranged on the front side of the optical member 16 and can sandwich the outer peripheral edge portion of the optical member 16 between the side plate of the chassis 14 and the holder 19. The frame 17 can receive the liquid crystal panel 11 from the back side, and can hold the liquid crystal panel 11 with the bezel 13 disposed on the front side of the liquid crystal panel 11.

  The cold-cathode tube 18 is a linear light source (tubular light source), and is mounted in the chassis 14 in such a posture that its axial direction coincides with the long side direction (X-axis direction) of the chassis 14 as shown in FIG. A plurality of them are arranged along the short side direction (Y-axis direction) of the chassis 14 with their axes substantially parallel to each other and with a predetermined interval therebetween.

  The cold cathode tube 18 includes an elongated glass tube 18a having a circular cross section sealed at both ends, a pair of electrodes (not shown in FIG. 4) sealed inside the both ends of the glass tube 18a, glass A pair of lead terminals 18b and 18c projecting outward from both ends of the tube 18a are provided. The cold cathode tube 18 is a so-called straight tube type in which the glass tube 18a is in a straight line and the electrodes are distributed in two directions (right and left in FIGS. 3 and 4). The glass tube 18a is filled with mercury or the like, and a fluorescent material is applied to the inner wall surface thereof. The lead terminals 18b and 18c are both made of metal having conductivity, and are substantially elongated and project outward from the end of the glass tube 18a along the axial direction (X-axis direction) (opposite to the electrode side). It has a columnar shape, and its inner end is connected to the electrode in the glass tube 18a, so that it has the same potential as the electrode. The pair of left and right lead terminals 18b and 18c are different from each other by a length ΔL from the glass tube 18a (the longer lead terminal is labeled 18b and the shorter lead terminal is labeled 18c). However, this will be described later in connection with the manufacturing procedure of the cold cathode tube 18.

  The holder 19 is made of a synthetic resin exhibiting white with excellent light reflectivity, and as shown in FIG. 2, the holder 19 has a substantially box shape extending along the short side direction of the chassis 14 and having an open back surface. ing. A pair of holders 19 are attached to both end portions of the chassis 14 in the long side direction so that the end portions (non-light emitting portions) of the cold cathode tubes 18 arranged in parallel at the same position can be collectively covered. It has become.

  The lamp clips 20 are made of a synthetic resin exhibiting white having excellent light reflectivity, and are distributed in a predetermined distribution with respect to the inner surface of the bottom plate 14a of the chassis 14. The lamp clip 20 is fixed to the bottom plate 14 a of the chassis 14 and can hold a central portion (light emitting portion) excluding both end portions of each cold cathode tube 18. As a result, the distance between the cold cathode tube 18 and the bottom plate 14a of the chassis 14 can be maintained constant.

  Subsequently, the inverter board 21 necessary for supplying power to each cold cathode tube 18 has a circuit pattern on the surface, and various electronic components such as a transformer (not shown) are mounted on the surface. The inverter board 21 controls the turning on / off of the cold cathode tube 18 by applying an alternating voltage of a predetermined frequency to the cold cathode tube 18.

  As shown in FIG. 5, a pair of inverter boards 21 are attached to the back surface of the bottom plate 14a of the chassis 14 (the surface opposite to the installation surface of the cold cathode tubes 18). It is unevenly distributed at both end positions in the direction. The inverter substrate 21 has a rectangular shape in plan view, and the plate surface thereof is orthogonal to the plate surface of the bottom plate 14a of the chassis 14 (X-axis direction and Y-axis direction, the Z-axis direction that is the thickness direction of the liquid crystal display device 10). And the long side direction thereof coincides with the short side direction of the bottom plate 14a (the Y-axis direction, the direction perpendicular to the axial direction of the cold cathode tube 18). It is fixed by. Out of the long side ends of the inverter board 21, the outward long side ends (ends facing the connector 22) are individually fitted and connected to the connectors 22 described below. The connector connection protrusion 21a is provided so as to partially protrude outward (connector 22 side) along the X-axis direction. A plurality of connector connection protrusions 21a are arranged at equal intervals in the long side direction of the inverter board 21 (the Y-axis direction, the parallel direction of the cold cathode tube 18 and the connector 22), and have a substantially comb-like shape as a whole. There is no.

  As shown in FIG. 3, the connector 22 is for electrically relaying the inverter board 21 and each cold cathode tube 18, and is connected to the lead terminals 18b and 18c of each cold cathode tube 18 on one end side. The light source connection portion 22a to be connected to each other and the substrate connection portion 22b to be connected to the connector connection protrusion 21a of the inverter substrate 21 on the other end side. The output voltage output from the inverter board 21 is applied to the lead terminals 18 b and 18 c of the cold cathode tube 18 through the connector 22.

  The connector 22 will be described in more detail. The connector 22 has a generally block shape as a whole, and as shown in FIG. 6, a housing 24 having an insulating property made of a synthetic resin and a metal housing accommodated in the housing 24. It has the connection terminal 25 and the terminal pressurization member 26 (refer FIG. 7) assembled | attached to the housing 24. FIG.

  The housing 24 has a vertically symmetrical shape with respect to the axis of the cold cathode tube 18 (a line extending in the X-axis direction through the center of the cold cathode tube) in the plan view of FIG. 8, and is formed on the bottom plate 14 a of the chassis 14. It is attached to the attachment hole 14b via a holding member 23 described later. The connector 22 penetrates the bottom plate 14a in the thickness direction (Z-axis direction) in the mounted state, and the light source connection portion 22a protrudes to the back side of the connector 22 at a portion protruding from the bottom plate 14a to the front side. The board connecting portions 22b are respectively located at the positions.

  Among these, in the light source connection portion 22 a of the connector 22, a light source fitting portion 24 a capable of fitting the end portion of the cold cathode tube 18 is formed in the housing 24. The light source fitting portion 24a opens in the front direction (light emission side) along the Z-axis direction, and opens inward along the X-axis direction (the axial direction of the cold cathode tube 18). The end portion of the tube 18 can be fitted along the Z-axis direction from the front side.

  And the light source fitting part 24a is divided into 2 parts in the X-axis direction by the positioning wall part 22c equivalent to a positioning part. The end portion of the glass tube 18a of the cold cathode tube 18 can be accommodated in the inner portion (the left portion in FIG. 6) of the positioning wall portion 22c, whereas the outer portion (the right portion in the figure) can be cooled in the outer portion (the right portion in the figure). The lead terminal 18b or 18c of the cathode tube 18 can be accommodated. When the glass tube 18a moves in the axial direction (X-axis direction) on the positioning wall portion 22c of the light source fitting portion 24a, the sealing end portion abuts on the positioning wall portion 22c, thereby restricting further movement, thereby reducing the cold cathode. It has the function of positioning the tube 18.

  On the other hand, the board fitting portion 24b is provided with a board insertion hole 24b1 (see FIGS. 6 and 7) that opens inward along the X-axis direction (the axial direction of the cold cathode tube 18). The connector connection protrusion 21a of the board 21 can be fitted from the inside along the X-axis direction. The board fitting portion 24b is provided with a terminal mounting hole 24c that opens to the back side along the Z-axis direction. A connection terminal 25 described below is provided along the Z-axis direction with respect to the terminal mounting hole 24c. Can be inserted from the back side. This terminal mounting hole 24c is also formed in communication with the outside (right side) portion of the positioning wall portion 22c in the light source fitting portion 24a and penetrates the housing 24 in the Z-axis direction.

  As shown in FIG. 6, the connection terminal 25 includes a base portion 25 a having an L-shaped cross section, and is electrically connected to a lead terminal 18 b of the cold cathode tube 18 at one end side (the upper end side in the drawing) of the base portion 25 a. An elastic contact piece 25 b is provided which has an elastic contact piece 25 b and is electrically connected to a terminal portion (not shown) provided on the connector connection protrusion 21 a of the inverter board 21 on the other end side.

  The elastic contact piece 25b is arranged in the outside (right side) portion of the positioning wall portion 22c in the light source fitting portion 24a of the housing 24, and also in the Y-axis direction (the axial direction of the cold cathode tube 18 and the fitting of the lead terminal 18b). A pair is arranged in an opposing manner in a direction orthogonal to both of the alignment directions (see FIG. 8). Both elastic contact pieces 25b can be elastically deformed in a direction away from each other, that is, outward in the Y-axis direction. The lead terminals 18b and 18c of the cold cathode tube 18 can be fitted between the both elastic contact pieces 25b, and the lead terminals 18b and 18c can be elastically held in a sandwiched state between the two elastic contact pieces 25b. . A terminal pressurizing member 26, which is a separate component from the housing 24, is assembled from the front side to the light source fitting portion 24 a of the housing 24, and the terminal pressurizing member 26 is provided from the light source fitting portion 24 a to the front side. In the protruding first assembly position (see FIG. 7), the two elastic contact pieces 25b are separated from each other, but in the second assembly position (see FIG. 6) housed in the light source fitting portion 24a, both It has a pressurizing part (not shown) that pressurizes the elastic contact pieces 25b so as to make them approach each other.

  As shown in FIG. 6, the holding member 23 that holds the connector 22 configured as described above can be attached to the attachment hole 14 b of the bottom plate 14 a of the chassis 14. The holding member 23 is made of synthetic resin, has a substantially box shape that opens toward the front side, and is assembled to the connector 22 from the back side along the Z-axis direction. In the assembled state, the holding member 23 is configured to surround approximately half the back side of the connector 22, that is, the board connecting portion 22 b. The holding member 23 includes a bottom wall 23a disposed on the back side of the board connecting portion 22b, and four side walls 23b that rise from the outer peripheral end of the bottom wall 23a and have a substantially cylindrical shape as a whole. The bottom wall 23a closes the terminal mounting hole 24c in the housing 24 and holds the connection terminal 25 in a state of preventing the connection terminal 25 from coming off. The front end (front end) of the side wall 23b protrudes outward along the X-axis direction, and is engaged with the edge of the mounting hole 14b from the front side, so that the holding member 23 is attached to the chassis 14. On the other hand, a locking wall 23c that can be held in the attached state is provided. Moreover, although illustration is abbreviate | omitted, the same latching wall is each provided also in the front-end | tip of the both-sides wall located in a line with the Y-axis among each side wall 23b. The holding member 23 holds the connector 22 in an assembled state by a predetermined holding structure (not shown).

  As shown in FIGS. 4 and 5, each connector 22 having the above-described configuration is positioned corresponding to both end portions of the cold cathode tube 18 with respect to the chassis 14, that is, both end positions in the long side direction (X-axis direction) of the bottom plate 14 a. And a plurality of sets (corresponding to the number of cold cathode tubes 18) arranged along the short side direction (the Y-axis direction, the parallel direction of the cold cathode tubes 18) of the bottom plate 14a.

  Particularly in the present embodiment, as shown in FIG. 9, the distance Xx between the left and right connectors 22 in the X-axis direction and the dimension X1 between the two positioning wall portions 22c paired on the left and right are glass tubes. The dimension La between the sealed end portions 18a is set to a value obtained by adding the dimension difference ΔL between both the lead terminals 18b and 18c (X1 = La + ΔL). In the figure, the connector 22 is drawn in a simplified rectangular shape, and the connection terminals 25 and the like are omitted. Further, the arrangement pitch in the Y-axis direction between the connectors 22 is substantially equal to the arrangement pitch between the cold cathode tubes 18 and the arrangement pitch between the connector connection protrusions 21a, and is equally spaced.

  Next, a manufacturing method of the cold cathode tube 18 and an assembling procedure of the backlight device 12 will be described. First, the cold cathode tube 18 is manufactured by the lamp manufacturer through the following steps. As shown in FIG. 10, the hollow cylindrical glass tube 18 a having both ends opened is set in a standing posture (a posture in which the axis substantially coincides with the vertical direction), and a lower end portion of the fluorescent material stored in the tank 30. While immersing in the solution 31 (fluorescent material powder dispersed in a solvent) and evacuating the glass tube 18a from the upper end side by the vacuum pump 32, the fluorescent material solution 31 is introduced into the glass tube 18a. When the fluorescent material solution 31 reaches a predetermined height in the glass tube 18a, the vacuumed fluorescent material solution 31 is dropped by releasing the vacuum. Thereby, the fluorescent material is applied to the inner wall surface of the glass tube 18a. Thereafter, by drying, the fluorescent material layer 33 is attached to the inner wall surface of the glass tube 18a (see FIG. 11). The excess fluorescent material on the lower end side of the glass tube 18a is removed.

  Subsequently, as shown in FIG. 11, while maintaining the vertical posture, the electrode 34 with the lead terminal is inserted into the lower end portion (the end portion into which the fluorescent material is introduced) of the glass tube 18a, and then heated. A first constriction 35 is formed in the glass tube 18a to temporarily fix the electrode 34. Further, a second constriction 36 is formed in the glass tube 18a by heat processing also below the first constriction 35.

  Thereafter, the glass tube 18a is turned upside down as indicated by the arrow, and the end portion to which the electrode 34 is attached faces the upper side in the vertical direction. Next, as shown in FIG. 12, the lower end portion of the glass tube 18a is first inserted in the state where the lead terminal is protruded to the outside by heating while inserting the electrode 37 with the lead terminal into the lower end portion of the glass tube 18a. Is sealed.

  Next, when a getter material 38 containing mercury is inserted into the upper end portion of the glass tube 18a shown in FIG. 13 through the opening, the getter material 38 is placed above the electrode 34 by the second constriction 36 as shown in FIG. Supported. Then, after the glass tube 18a is heated to exhaust the inside of the glass tube 18a to remove impure gas, the opening at the upper end of the glass tube 18a is sealed by heat processing (see FIG. 13). Subsequently, the getter material 38 is heated at a high frequency to gasify the mercury contained in the getter material 38 and supply the gas into the glass tube 18a. Thereafter, the position of the first constriction 35 (the lead terminal is exposed to the outside). At the position), the glass tube 18a is sealed by heat processing (secondary sealing), and the getter material 38 and the like are removed.

  According to this manufacturing process, the upper end portion of the glass tube 18a shown in FIG. 10 becomes the primary sealing side end portion 18f which is sealed first, and the end portion where the fluorescent material is introduced at the lower end portion is the secondary sealing side end portion. Part 18s.

  Thereafter, the lead terminals protruding from the sealing end portions at both ends of the glass tube 18a are cut to a required size. At this time, for example, the secondary sealing side end portion 18s, that is, the lower end portion when the fluorescent material is introduced. The lead terminal 18b on the side that has been cut is cut so as to be longer than the primary sealing side end 18f, that is, the lead terminal 18c on the side that has become the upper end when the fluorescent material is introduced, by a predetermined dimension ΔL.

  The dimensional difference ΔL between the lead terminals 18b and 18c at this time satisfies ΔL> (x + y) in consideration of the tolerance x of the processing dimension of the glass tube 18a and the tolerance y of the processing dimension of the lead terminals 18b and 18c. It is desirable to determine as follows. Here, the tolerance means a difference between a maximum value and a minimum value allowed as actual dimensions after processing when processing is performed with a design dimension (reference dimension) as a target. For example, when the reference dimension (La) of the glass tube 18a is 700 mm, the tolerance x is 2 mm (± 1 mm) when the dimension after processing is allowed in the range of 699 mm to 701 mm. When the dimensional error when cutting the lead terminals 18b and 18c is ± 0.5 mm, that is, when the tolerance y of the processing dimensions of the lead terminals 18b and 18c is 1 mm, the dimensional difference ΔL between the lead terminals 18b and 18c is The sum of both tolerances (x + y) = a value larger than 3 mm (ΔL> (x + y)), for example, 4 mm which is at least 1 mm larger than (x + y) is desirable. In this way, even if the processing errors of the glass tube 18a and the lead terminals 18b and 18c are accumulated, there is a clear difference in the positions of the tips of the lead terminals 18b and 18c.

  The fluorescent material of the cold cathode tube 18 includes a plurality of types of fluorescent material particles corresponding to emission colors such as R, G, and B, and the particle size and specific gravity are different for each type. . On the other hand, in the fluorescent material coating process in the manufacturing process of the cold cathode tube 18, since gravity is used as described above, the distribution of the various fluorescent material particles applied is likely to be biased. In the cold cathode tube 18, anisotropy of light emission characteristics (color unevenness and brightness unevenness) occurs in the axial direction. For example, the secondary sealing side end portion 18s that is lower in the manufacturing process of the fluorescent material at the time of manufacture is slightly more red-colored than the primary sealing side end portion 18f that is upper. Bias (axial anisotropy) may occur. Since the anisotropy of the light emission characteristics occurs due to the manufacturing process, the same tendency is observed in all manufactured cold cathode tubes 18.

  In view of this, in the present embodiment, as described above for each cold cathode tube 18, the lead terminal 18b of the secondary sealing side end 18s is larger than the lead terminal 18c of the primary sealing side end 18f by a predetermined dimension ΔL (for example, 4mm) is cut to be longer. Therefore, by comparing the lengths of the lead terminals, it can be clearly distinguished which is the secondary sealing side end 18s and which is the primary sealing side end 18f.

  Therefore, when the worker installs the cold cathode tube 18 manufactured as described above in the chassis 14, as shown in FIG. 4 (shown schematically enlarged in FIG. 9), adjacent cold cathode tubes 18 are mounted. The directions of the cathode tubes 18 are alternately reversed. For that purpose, the short lead terminal 18c of the cold cathode tube 18 is pushed into the right connector 22 so that the primary sealing side end 18f is on the right side, and the secondary sealing side end 18s on the opposite side is pushed. When the longer lead terminal 18b is pushed into the left connector 22, the lead terminal 18b is connected to the right connector 22 so that the secondary sealing side end 18s is on the right side of the cold cathode tube 18 adjacent to it. Then, the lead terminal 18c on the opposite side is pushed into the connector 22 on the left side, and this is repeated.

  At this time, in the connector 22 on the side that accommodates the primary sealing side end 18f side (the side with the short lead terminal 18c) of the cold cathode tube 18, the primary sealing side of the cold cathode tube 18 as shown in FIG. The end portion 18 f is brought into contact with the positioning wall portion 22 c of the connector 22. At the end opposite to the cold cathode tube 18, that is, the secondary sealing side end 18s, as shown in FIG. 15, the secondary sealing side end 18s extends from the positioning wall portion 22c in the X-axis direction. Although separated, the lead terminal 18b is set to have a dimension longer than the lead terminal 18c by ΔL, so there is no possibility that the lead terminal 18b is detached from the elastic contact piece 25b.

  When each cold-cathode tube 18 is set as described above, as described above, the opposing distance Px in the X-axis direction of each pair of left and right connectors 22 is such that the dimension X1 between the positioning wall portions 22c is the sealing of the glass tube 18a. Since it is set to a value (X1 = La + ΔL) obtained by adding the dimension difference ΔL between the lead terminals 18b and 18c to the dimension La between the toe ends, as shown in FIGS. 18b and 18c are arranged so that the tip ends thereof are aligned at the same position in the connector 22, and the positions of the primary sealing side end 18f and the secondary sealing side end 18s of the glass tube 18a are shown in FIG. As shown in the figure, they are regularly arranged while being displaced alternately in the axial direction.

  Therefore, particularly in the first embodiment, the entire backlight device 12 is overviewed after assembling all the cold cathode tubes 18 while paying attention to the position of the end of the glass tube 18a of the cold cathode tubes 18, and even during the assembling. If you look at the whole, you can easily find the part where the regularity is broken, so it is immediately determined that the direction of the cold cathode tube 18 is reverse to the desired direction. can do.

  In the present embodiment, when the tolerance of the processing dimension of the glass tube 18a is x and the tolerance of the processing dimension of the lead terminals 18b and 18c is y, the length difference ΔL between the pair of lead terminals 18b and 18c is ΔL Since> (x + y) is set, the direction of the cold cathode tube 18 can be reliably identified even if errors in processing the glass tube 18a and the lead terminals 18b and 18c accumulate.

  In using the liquid crystal display device 10 of the present embodiment, when the power of the liquid crystal display device 10 is turned on, power is supplied to each cold cathode tube 18 from the inverter board 21 constituting the backlight device 12 via the connector 22. As a result, each cold cathode tube 18 is turned on and an image signal is supplied to the liquid crystal panel 11. Light emitted from each cold cathode tube 18 passes through the optical member 16, and is irradiated on the liquid crystal panel 11 as light having substantially uniform light emission characteristics in the plane direction of the backlight device 12. Then, a desired image is displayed on the display surface of the liquid crystal panel 11 by controlling the amount of transmitted light according to the alignment state of the liquid crystal molecules of the liquid crystal layer in the liquid crystal panel 11 controlled based on the image signal.

  In the backlight device 12 of the present embodiment, the ends of the adjacent cold cathode tubes 18 are alternately switched to the primary sealing side end 18f and the secondary sealing side end 18s. Thereby, even if each cold cathode tube 18 has anisotropy in the light emission characteristic in the axial direction, the backlight device 12 as a whole tends to cancel the anisotropy. That is, color unevenness is less likely to occur.

<Embodiment 2>
FIG. 16 shows a second embodiment of the present invention. In the second embodiment, the distance between the left and right connectors 22 in the X-axis direction is the same as the dimension X1 between the two positioning wall portions 22c paired on the left and right, and the reference dimension between the sealing ends of the glass tube 18a. It differs from the first embodiment in that it is set to be substantially the same (X1 = La) in consideration of tolerance with La (X1 = La + ΔL in the first embodiment), and the other points are the same as in the first embodiment. It is.

  In this configuration, the glass tube 18 a of the cold cathode tube 18 is set while being positioned so as to fit between the positioning wall portions 22 c of the connector 22. On the other hand, since the lengths of the lead terminals 18b and 18c at the sealed ends are different by ΔL, when the plurality of cold cathode tubes 18 are sequentially assembled to the connector 22, the lead terminals 18b and 18c are respectively assembled as shown in FIG. The positions of the tips are regularly arranged while being displaced alternately in the axial direction.

  Therefore, in the case of the second embodiment, if the entire backlight device 12 is viewed after assembling all the cold cathode tubes 18 while paying attention to the tips of the lead terminals 18b and 18c, the regularity is broken. It is possible to easily find the spot where it is. Of course, even during assembly, it is possible to confirm that the positions of the tips of the lead terminals are aligned and immediately determine that the direction of the cold cathode tube 18 is reverse to the desired direction.

  Therefore, the second embodiment also has the same effect as the first embodiment.

<Other embodiments>
The present invention is not limited to the above-described embodiments. For example, the following embodiments are also included in the technical scope of the present invention.

  (1) In each of the above embodiments, the arrangement dimension between the pair of connectors 22 holding one cold cathode tube is determined in association with the dimension La between the sealing ends of the glass tube 18a. Not limited to this, any dimension may be set as long as it is larger than the dimension La between the sealed ends of the glass tube 18a and can be connected to the lead terminals 18b and 18c.

  (2) In each of the above embodiments, each connector 22 is provided with the positioning wall portion 22c with which the end of the glass tube 18a of the cold cathode tube 18 abuts. It is good also as a structure which makes positioning of these. Furthermore, since the directionality of the cold cathode tube 18 itself can be confirmed by the length of the lead terminal, it is not always necessary to provide the positioning portion in the connector 22.

  (3) In each of the above embodiments, the connector 22 is provided, and the cold cathode tube 18 is pushed in from the side facing the chassis 14 of the backlight device 12 to hold the cold cathode tube 18 connected. The assembly work of the pipe 18 can be performed efficiently. However, even if it is not necessarily a connection method using a connector, an electric wire may be individually soldered to each lead terminal and this may be assembled to the chassis of the backlight device. Even in this case, since the directionality of the cold cathode tube can be confirmed by confirming the length of the lead terminal, it is arranged so as to cancel the axial anisotropy of the emission characteristics of the cold cathode tube. Is possible. Alternatively, a plurality of cold cathode tubes may be arranged with their directions aligned, and each lead terminal may be connected to the substrate at once by soldering or laser welding. Even in this case, in the operation of arranging a plurality of cold cathode tubes in the form in which their directions are aligned, the directivity of each cold cathode tube can be easily confirmed, so that the working efficiency is improved.

  (4) In each of the above embodiments, the cold cathode tubes 18 are set so that they are alternately reversed in the reverse direction. However, two or more groups are formed and the reverse directions are alternately reversed in each group. It may be set so as to be, or in one area, it is set to be alternately reversed in every other line, and in another area, it is set to be alternately reversed in every two lines. In addition, the number of cold-cathode tubes belonging to groups arranged so that the directions are alternately reversed may be varied depending on the region.

  (5) In each of the above-described embodiments, a cold cathode tube is exemplified as the discharge tube. However, other types of discharge tubes such as a hot cathode tube may be used as long as a lead terminal is provided at the end of the glass tube. Good.

  (6) In each of the above embodiments, the color unevenness is shown as an example of the axial anisotropy in the light emission characteristics of the discharge tube. However, the present invention is not limited to this. The present invention can also be applied to a discharge tube having characteristics. Moreover, although the fluorescent material was introduced in the state which stood the glass tube and it illustrated about the manufacturing method which carries out the primary sealing and secondary sealing of the glass tube edge part in order, this invention relates to the discharge tube manufactured by the manufacturing method which concerns In short, in any manufacturing method, when using a discharge tube that has caused axial anisotropy in the light emission characteristics of the discharge tube due to some reason in the manufacturing process Can be widely applied.

  Further, in each of the above embodiments, an arrangement mode in which the directions are alternately changed in order to cancel the light emission characteristics of each discharge tube has been shown. However, the present invention is not limited to this, and the orientation is used in order to make use of the light emission characteristics of each discharge tube. The present invention can also be applied to an illumination device for a flat display device that is arranged in a uniform manner.

  (7) In each of the above-described embodiments, the liquid crystal display device using a liquid crystal panel as the display panel has been exemplified. However, the present invention can also be applied to a flat display device using another type of display panel.

  (8) In each of the above-described embodiments, the television receiver provided with the tuner has been exemplified. However, the present invention can also be applied to a flat display device that does not include the tuner.

1 is an exploded perspective view showing a schematic configuration of a television receiver according to Embodiment 1 of the present invention. An exploded perspective view showing a schematic configuration of a liquid crystal display device provided in the television receiver Sectional drawing which shows the cross-sectional structure along the long side direction of a liquid crystal display device Plan view of chassis with cold cathode tubes and connectors Bottom view of chassis with cold cathode tubes and connectors Sectional view showing connection structure of cold cathode tube, connector and inverter board The front view which shows the state which assembled | attached the terminal pressurization member with respect to the housing in the 1st assembly position. The top view which shows the state which assembled | attached the terminal pressurization member with respect to the housing in the 1st assembly position. A plan view schematically showing a state where a cold cathode tube is set in a chassis Sectional drawing showing the process which introduce | transduces a fluorescent material solution in a glass tube among the manufacturing processes of a cold cathode tube Sectional drawing showing the state which temporarily fixed the electrode in the manufacturing process of the cold cathode tube Sectional drawing showing the state which primary sealing was completed in the manufacturing process of a cold cathode tube Sectional drawing showing the state where the getter material was put in the manufacturing process of the cold cathode tube The top view which shows the state which set the primary sealing side edge part of the cold cathode tube to the connector The top view which shows the state which set the secondary sealing side edge part of the cold cathode tube to the connector Schematic plan view showing one end side of a chassis on which a cold cathode tube is set The schematic top view which shows the one end side of the chassis which concerns on Embodiment 2 of this invention and set the cold cathode tube

Explanation of symbols

10. Liquid crystal display device (flat display device)
11 ... Liquid crystal panel (display panel)
12 ... Backlight device (illumination device for flat display device)
14 ... Chassis 18 ... Cold cathode tube (discharge tube)
18a ... Glass tube 18b ... Lead terminal (longer one)
18c: Lead terminal (shorter)
18f ... Primary sealing side end 18s ... Secondary sealing side end 22 ... Connector 22c ... Positioning wall (positioning part)
25 ... Terminal fitting 25b ... Elastic contact piece

Claims (13)

Both ends of the glass tube are sealed, and lead terminals are protruded from the sealed end portions, and a plurality of discharge tubes whose light emission characteristics are anisotropic in the axial direction and the discharge tubes are held in parallel. In the one with the chassis,
In the discharge tube, the lead terminal on one end side is different in length from the lead terminal on the other end side, and the discharge tube is arranged such that the lead terminals having different lengths are in a predetermined direction. An illuminating device for a flat display device. 2. The flat display device illumination according to claim 1, wherein the discharge tubes are arranged such that lead terminals having different lengths are alternately arranged in a predetermined number along the parallel direction of the discharge tubes. apparatus. The discharge tube has a configuration in which a fluorescent material is attached to the inner surface of a glass tube having openings at both ends, and then one end side of the glass tube is primarily sealed and the opposite side is secondarily sealed. The illumination device for a flat display device according to claim 1. After the discharge tube is in a state of standing glass tubes having openings at both ends, the fluorescent material is introduced from one end and the fluorescent material is attached to the inner surface of the glass tube, and then both ends of the glass tube The flat panel display illumination device according to any one of claims 1 to 3, wherein both ends of the glass tube are sealed in a state in which a discharge lead terminal protrudes outside. The flat panel display lighting device according to any one of claims 2 to 4, wherein the predetermined number is one. The chassis is provided with a connector corresponding to each end of the discharge tube, and the connector contacts the lead terminal by pushing the lead terminal of the discharge tube from the side facing the chassis. A flat panel display illumination device according to any one of claims 1 to 5, wherein a terminal fitting is provided. The said terminal metal fitting is comprised by a pair of elastic contact piece mutually opposingly arranged so that the opposite side to the said chassis may be opened, The Claim 1 thru | or 6 characterized by the above-mentioned. Lighting device for flat display device. When the tolerance of the processing dimension of the glass tube in the discharge tube is x and the tolerance of the processing dimension of the lead terminal is y, the length dimension difference ΔL of the pair of lead terminals satisfies ΔL> (x + y). The illumination device for a flat display device according to claim 1, wherein the illumination device is a flat panel display device. 9. The connector according to any one of claims 1 to 8, wherein the connector is provided with a positioning portion in which a sealing end portion of the glass tube of the discharge tube abuts in the axial direction to perform positioning. An illumination device for a flat display device according to item. The pair of connectors that hold the cold cathode tubes at both ends are such that the distance between the positioning wall portions is a value obtained by adding ΔL to the interval between the sealed end portions of the glass tube of the cold cathode tube. The illumination device for a flat display device according to claim 9, which is arranged. A display device for a flat display device, comprising: the illumination device according to any one of claims 1 to 10; and a display panel that performs display using light from the illumination device. The flat display device according to claim 111, wherein the display panel is a liquid crystal panel in which liquid crystal is sealed between a pair of substrates. A television receiver comprising the flat display device according to claim 10 or 11.

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