JP2006164839A - Backlight unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure that distribution unification of brightness at a tube bending part can be promoted by a retaining structure of the tube bending part of each lamp without extending any unification measures on the brightness on a diffusion plate or diffusion sheet in a backlight unit in which a plurality of bent fluorescent lamps are installed in parallel. <P>SOLUTION: In the backlight unit in which a plurality of fluorescent lamps 1 having U shaped or horseshoe shaped tube bending part 1A are arranged in parallel in a reflecting case 104, each tube bending part of the fluorescent lamp is made to be retained by a bending retaining member 122 extended from the reflecting case, so that the light from the respective tube bending part is shielded at the time of lighting of each fluorescent lamp. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a backlight unit.

  In recent years, with the widespread use of large liquid crystal panels, the development of direct type backlight units in which a plurality of straight tubes and bent fluorescent lamps are arranged in parallel is increasing. FIG. 10 is an exploded perspective view of a conventional backlight unit. This backlight unit includes a plurality of fluorescent lamps 1 bent into a U shape, power supply electrodes 111, side plates 112 for holding the electrodes, and an inverter power supply (not shown). ) To a power supply electrode 111 on both sides, a harness 103 for supplying a high frequency and sine wave voltage, a lower frame 104 for fixing the fluorescent lamp 1 and side plates 112 on both sides to predetermined positions, and light from a plurality of fluorescent lamps 1 in a predetermined direction ( In FIG. 10, a reflection plate 105 that reflects upward), a diffusion plate 106 and diffusion sheets 107 and 108 for uniformly diffusing light from the plurality of fluorescent lamps 1, and an upper frame 109 are arranged as shown in the figure. Assemble.

  FIG. 11 is a plan view of a conventional backlight unit, and FIG. 12 is an enlarged view of a lamp support holder. Conventionally, as shown in FIG. 12, in order to fix the fluorescent lamp 1 of a U-shaped or U-shaped bent tube to the lower frame 104, each fluorescent lamp 1 is held on both sides by a lamp support holder 121. The lamp support holders 121 are arranged so as to cross the lower frame 104 in a straight line. In addition, the tube bending portion 1A of each of the bent fluorescent lamps 1 is not held, and each straight portion is only supported by the lower frame 104 by the lamp support holder 121.

  FIG. 13 is an enlarged view of the holding structure of the tube bending portion 1A of the backlight unit using the conventional bent fluorescent lamp 1. FIG. As shown in FIG. 13, there is no member for holding the tube bending portion 1A of the bent fluorescent lamp 1, and only the holding of the bent fluorescent lamp 1 at the straight portion by the lamp support holder 121 described above. Then, in order to make the luminance distribution of the bent portion 1A uniform in the entire unit, the thickness of the diffusion plate 106 that is strongly influenced by the light emitted from the tube bent portion 1A is adjusted and the light shielding pattern is printed on the diffusion sheets 107 and 108. The luminance distribution on the entire light emitting surface of the backlight unit was made uniform.

  However, in the conventional backlight unit, printing is performed on the diffusion plate or the like in order to make the luminance distribution uniform in the tube bent portion 1A of the bent fluorescent lamp 1, and therefore, due to the variation in the position of the tube bent portion 1A and the printing position. There is a problem that the luminance distribution varies.

Conventionally, as shown in FIGS. 11 and 12, since the lamp support holders 121 for each bent fluorescent lamp 1 have been arranged continuously on a straight line, as shown in the luminance distribution graph of FIG. The brightness is lowered at a local portion corresponding to the lamp support holder 121, and a brightness difference A is produced from other places, and the shadow appears as a line in the effective light emitting area. For this reason, conventionally, measures have been taken to hide shadows using the diffusion sheets 107 and 108, reduce the transmittance of the diffusion plate 106, and widen the internal space to make it difficult to see on the screen. However, due to this countermeasure, there has been another problem such as a decrease in luminance.
Japanese Patent Laid-Open No. 7-288023

  The present invention has been made in view of the problems of the prior art as described above, and is a backlight unit in which a plurality of bent fluorescent lamps are arranged side by side. It is an object of the present invention to provide a backlight unit that can achieve a uniform luminance distribution in the tube bent portion with the tube bent portion holding structure of each lamp without being provided.

  In the backlight unit in which a plurality of fluorescent lamps are arranged in parallel, the present invention reduces the partial difference in luminance by arranging the holders that support the fluorescent lamps so as not to be arranged in a straight line. It is an object of the present invention to provide a backlight unit that can achieve uniform luminance while suppressing a decrease in luminance without taking measures for uniform luminance on a diffusion plate or a diffusion sheet.

  The invention of claim 1 is a backlight unit in which a plurality of fluorescent lamps having U-shaped or U-shaped tube bent portions are arranged in parallel in a reflecting case, and the tube bent portions of each of the fluorescent lamps are arranged in the reflecting case. It is held by a bent portion holding member extending from the tube so that light from the bent portion of the tube is shielded when each of the fluorescent lamps is turned on.

  According to a second aspect of the present invention, in the backlight unit in which a plurality of fluorescent lamps are arranged in parallel in the reflection case, an intermediate portion of each of the fluorescent lamps is held by the holder with respect to the reflection case. Is arranged so that it is not aligned with other holders.

  According to a third aspect of the present invention, there is provided a backlight unit in which a plurality of fluorescent lamps having U-shaped or U-shaped tube bent portions are arranged in parallel in a reflective case, and the tube bent portions of the fluorescent lamps are arranged in the reflective case. The fluorescent lamp is held by a bent portion holding member so that light from the bent portion of the fluorescent lamp is shielded when each of the fluorescent lamps is turned on. And each holder is arranged so as not to be aligned with other holders.

  According to the present invention, it is possible to provide a backlight unit that is bright and has a uniform luminance over the entire light emitting surface.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  (First Embodiment) FIG. 1 is a top view of a backlight unit according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view showing a tube bending portion holding structure, and FIG. 3 is a lamp support. It is an enlarged view of a holder part. The backlight unit of the present embodiment has the same configuration as that of the conventional example shown in FIG. 10, and includes a plurality of bent fluorescent lamps 1 such as a U-shaped bent fluorescent lamp or a U-shaped bent fluorescent lamp. It arrange | positions on the flame | frame 104, the electrode 111 for the electric power supply of a housing | casing side is connected to those electrode parts, a high voltage | pressure high frequency voltage is supplied to each fluorescent lamp 1 through the harness 103 from an inverter power supply (not shown), and it lights it. A reflector 105 is disposed on the lower frame 104 so that the light from the fluorescent lamp 1 is emitted to the front side. A side plate 112 is provided at the side of the lower frame 104, and the lower frame 104 and the side plate 112 constitute a box-shaped lamp case. Further, although not seen in FIG. 1, the diffusion plate 106 and the diffusion sheets 107 and 108 for uniformly diffusing the light from the plurality of fluorescent lamps 1 and the upper frame 109 are arranged on the upper side of the fluorescent lamp 1 as in the prior art. Arranged and assembled together.

  A bent portion holding member 122 is provided on the side plate 112 on the tube bent portion 1A side of each of the plurality of bent fluorescent lamps 1, and as shown in FIG. 2, the bent portion holding member 122 allows the bent portion of each fluorescent lamp 1 to be bent. 1A is held from above and light from the tube bending portion 1A is shielded. As a result, according to the present embodiment, the tube bending portion 1A is held by the opaque bending portion holding member 122 without printing the diffusion plate or changing the thickness of the diffusion sheet as in the prior art. Only by this, the luminance distribution of the tube bending portion can be made uniform over the entire surface.

  In the illustrated embodiment, the bent portion holding member 122 has the same width on both sides and on the center side. However, if it is necessary to make the luminance distribution more uniform, By making the width narrower than that at the center, it is possible to make the luminance distribution uniform over the entire light emitting surface.

  As shown in FIG. 3, in the backlight unit of the present embodiment, each of the plurality of lamp support holders 121 is arranged at a position shifted from each other so as not to be aligned on a straight line. The straight portion of the fluorescent lamp 1 is held from the lower side with respect to the lower frame 104. As a result, as shown in FIG. 4, according to the present embodiment, the luminance drop B at the lamp holding holder support portion is suppressed (B <A) smaller than the conventional one (luminance difference A in FIG. 14). And the luminance distribution over the entire surface can be made uniform.

  (Second Embodiment) FIG. 5 is a sectional view of a backlight unit according to a second embodiment of the present invention, FIG. 6 is a diagram showing a luminance gradient of the backlight unit, and FIG. It is the figure which expanded the edge part of the backlight unit of 6. FIG. In the backlight unit of the present embodiment, a plurality of flat fluorescent lamps 1 are arranged in parallel to prevent contact between the flat fluorescent lamp 1 and the inclined portion of the reflecting plate 105, thereby simplifying the reflecting plate structure. Therefore, the inclined portion is eliminated, and the reflecting plate side portion 105A is bent vertically. In order to flatten the luminance gradient, a height difference of B is provided so that the fluorescent lamp 1 'near the end of the backlight unit approaches the screen side on which the diffusion plate 106, the diffusion sheet 107, etc. are disposed. It is arranged. Since the brightness gradient of the direct type backlight unit changes depending on the number of lamps used, the installation height difference B of the fluorescent lamp 1 ′ at the end position must be changed according to the brightness gradient. Decide on the appropriate one accordingly. According to the present embodiment, it is not necessary to form an inclined portion at the side end portion of the reflector 105, the structure can be simplified, and the lamp installation height difference B can be appropriately set according to the luminance gradient. The brightness difference of the backlight unit can be reduced.

  (Third Embodiment) FIG. 8 is a view showing the structure of a lamp holding portion in a backlight unit according to a third embodiment of the present invention. In the backlight unit of the present embodiment, a plurality of bent lamps 1 bent in a U-shape or U-shape and having a flat lamp tube are arranged as shown in FIG. . And in this Embodiment, as shown in FIG. 8, the straight part of each bending fluorescent lamp 1 is hold | maintained with the lamp holding holder 125, and is fixed to the predetermined position. The lamp holding holder 125 is made of a white or translucent and elastic synthetic resin, and is held by loading the straight portion of the bent fluorescent lamp 1 by pushing it through the opening. According to the present embodiment, the flat tube portion of the straight portion of the bent fluorescent lamp 1 can be supported reliably from both sides without being attenuated.

  In the case of this embodiment, the present invention can be applied not only to the bent fluorescent lamp 1 but also to a backlight unit in which a plurality of flat straight tube lamps are arranged in parallel. In the case of a backlight unit using flat and straight tube lamps, a slant cut 125A is provided in a flexible lamp holding holder 125 as shown in FIG. 9, and the fluorescent lamp 1 is loaded into the cut 125A to be inclined. It is also possible to have a configuration in which it is held in a state.

The top view of the backlight unit of the 1st Embodiment of this invention. Sectional drawing of the tube bending part holding structure of the bending fluorescent lamp in the backlight unit of the 1st Embodiment of this invention. The enlarged view of the lamp | ramp support holder part in FIG. The figure which shows the luminance distribution of the backlight unit of the 1st Embodiment of this invention. Sectional drawing of the backlight unit of the 2nd Embodiment of this invention. The figure which shows the luminance distribution of the backlight unit of the 2nd Embodiment of this invention. The enlarged view of the side edge part of the backlight unit of the 2nd Embodiment of this invention. Sectional drawing which shows the structure of the lamp | ramp holding | maintenance part of the 3rd Embodiment of this invention. Sectional drawing which shows the other structure of the lamp | ramp holding | maintenance part of the 3rd Embodiment of this invention. The exploded perspective view of the conventional backlight unit. The top view in which the conventional backlight unit was partly cut away. The enlarged view of the lamp | ramp support part of the conventional backlight unit. Sectional drawing of the pipe | tube bending part holding | maintenance part of the backlight unit using the conventional bending fluorescent lamp. The figure which shows the luminance distribution of the conventional backlight unit.

Explanation of symbols

1 bent fluorescent lamp 1A tube bent portion 104 lower frame 105 reflecting plate 109 upper frame 112 side plate 121 lamp support holder 122 bent portion holding member

Claims (3)

  In a backlight unit in which a plurality of fluorescent lamps having U-shaped or U-shaped tube bent portions are arranged in parallel in a reflective case, the bent portions that extend the tube bent portions of the fluorescent lamps from the reflective case A backlight unit characterized by being held by a holding member so as to block light from the bent portion of the tube when each of the fluorescent lamps is turned on.   In a backlight unit in which a plurality of fluorescent lamps are arranged in parallel in a reflective case, an intermediate portion of each of the fluorescent lamps is held by the holder with respect to the reflective case, and each holder is aligned with another holder. Backlight unit characterized by being arranged in line with In a backlight unit in which a plurality of fluorescent lamps having U-shaped or U-shaped tube bent portions are arranged in parallel in a reflective case,
Holding the bent portion of each fluorescent lamp with a bent portion holding member extending from the reflecting case, so that the light from the bent portion of the fluorescent lamp is shielded when each fluorescent lamp is turned on,
A backlight unit characterized in that an intermediate portion of each of the fluorescent lamps is held by a holder with respect to the reflection case, and the holders are arranged so as not to be aligned with other holders.

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