JP3653274B2 - Backlight device and liquid crystal display device - Google Patents

Description

The present invention relates to a direct backlight device and a liquid crystal display device used in a liquid crystal display device.

  With the increase in the size of non-light-emitting displays such as liquid crystal displays, it is inevitable that the fluorescent tube used for the backlight will be long. In addition, the smaller the inner diameter of the fluorescent tube, the higher the luminous efficiency. Therefore, it is desirable to make the tube thin in addition to the long tube, and the mechanical strength (particularly against bending) of the fluorescent tube alone is very weak. Become.

  In particular, when considering a direct-type backlight, the fluorescent tube is usually positioned using a rubber holder that insulates the solder joint between the lead wire from the fluorescent tube electrode and the power circuit harness. When the fluorescent tube is bent and bent, it causes a large luminance unevenness, and in the worst case, the fluorescent tube is destroyed.

  In order to prevent this phenomenon, a positioning mechanism member (lamp clip) is usually used at one or two points in the length direction of the fluorescent tube.

  Various proposals have been made for a fluorescent tube holder structure of a backlight device used in a liquid crystal display device or the like, but there are many proposals for a small liquid crystal display device, and the fluorescent tube holder for a small liquid crystal display device has a short tube length. Basically, the method of supporting only the vicinity of both ends of the fluorescent tube, or the method of supporting the whole and having an opening only in the light irradiation direction, and the method for supporting the intermediate portion of the fluorescent tube, are proposals for lighting fixtures. Is helpful.

  JP-A-9-115326 (Patent Document 1) and JP-A-10-326516 (Patent Document 2) are disclosed as proposals for this type of fluorescent tube holder.

  In Patent Document 1, there is a fluorescent lamp holder that is flexible and has a fluorescent lamp holder that is gripped and attached to a partially-circular grip ring material that has an opening in a part thereof. A plurality of locking tools that engage with the locking holes provided in the mounting body are provided by shifting the locking tools in the circumferential direction of the grip ring, thereby engaging with the locking holes provided in the mounting body depending on the fluorescent lamp mounting location. Proposal that the user can select the direction in which the user takes out the fluorescent lamp from the fluorescent lamp holder by selecting and using the appropriate fasteners, so that the fluorescent lamp and the fluorescent lamp holder can be detached without damaging the fluorescent lamp holder. It is.

In patent document 2, it consists of the reflecting plate for raising illuminance, and the attachment for attaching this reflection plate to the tube part of a fluorescent lamp, and the attachment has a first boss having a head and a neck, A second boss having a height lower than the boss and a holder portion for fitting and fixing the tube portion of the fluorescent lamp, and the reflector includes an insertion portion and a neck portion for inserting the head portion of the first boss; A first hole having a holding portion for engaging and holding the fixture, and the second boss is received when the first boss is inserted into the first hole and then moved and engaged with the neck. The second reflector hole is provided to fix the fixture to the reflector, so that it is easy to mount and adjust, and a reflector assembly for a fluorescent lamp that is easy to handle is proposed.
JP-A-9-115326 JP-A-10-326516

  As described above, also in the liquid crystal display device, at least one or two fluorescent tube intermediate portions are provided in order to maintain the performance and quality of the device in response to the lengthening and narrowing of the fluorescent tube of the backlight device accompanying an increase in size. It is necessary to support at a point, and a lamp holder having a shape including Patent Document 1, Patent Document 2, and the like is required.

  Due to the lengthening and narrowing of the fluorescent tube of the backlight device, and in addition to the increase in the number of tubes, the position variation of the fluorescent tube may cause uneven brightness on the display screen, and the fluorescent tube moves in all directions. In order to prevent this, the lamp holder has to be in contact with the fluorescent tube in some form, and there is a problem that a slight luminance unevenness occurs at the portion, and the conventional lamp holder mainly prevents the destruction of the fluorescent tube. In addition to this, it is necessary to consider the display quality by the lamp holder itself and its arrangement method.

In the present invention, in a direct type backlight device having a plurality of fluorescent tubes arranged in a row so that the longitudinal direction is substantially the same direction, and a support portion that supports the vicinity of both ends of the fluorescent tubes A plurality of lamp holders for supporting the fluorescent tubes between the support portions, and the lamp holders adjacent to each other in the arrangement direction of the plurality of fluorescent tubes are arranged so that positions in the longitudinal direction of the fluorescent tubes are different. Features.

Accordingly, it is possible to provide a backlight device that can prevent uneven brightness on the information display surface when the backlight device is used in a display device such as a liquid crystal display device.

In the present invention, the lamp holders are arranged in a staggered manner.

Thereby, similarly to the above, when the backlight device is used in a display device such as a liquid crystal display device, it is possible to provide a backlight device that can prevent uneven brightness on the information display surface.

A liquid crystal display device including the direct backlight device and a liquid crystal panel is provided .

Therefore, luminance unevenness in a liquid crystal panel displaying information can be prevented, and a high-quality liquid crystal display device can be provided.

In the present invention, the lamp holder includes a protrusion that protrudes further toward the liquid crystal panel than the plurality of fluorescent tubes.

Accordingly , warping of the diffusion plate and the like can be prevented, and thus uneven brightness in the liquid crystal panel as an information display surface can be prevented, and a higher quality liquid crystal display device can be provided.

In the present invention, it is possible to improve the quality with respect to luminance unevenness by not concentrating the influence of the lamp holder on the optical path in a specific portion.

  As an embodiment of the present invention, a direct backlight device for a liquid crystal display device will be described with reference to FIGS.

  A first embodiment will be described with reference to FIGS.

  FIG. 1 is a front / side view of the periphery of the liquid crystal panel and the backlight device. In FIG. 1, 1 is a fluorescent tube, 2 is a lamp holder, 3 is a reflector, 4 is a fluorescent tube support, 5 is a diffuser, and 6 is a liquid crystal panel. The reflector 3, the fluorescent tube support 4, the lamp holder mounting hole, and the substrate mounting boss (not shown) are formed by integral molding. In addition, the lamp holder 2 has a partially circular fluorescent tube grip shape having an opening in a part thereof, and is made of a transparent acrylic material having flexibility.

  FIG. 2 is a view showing the relationship between the lamp holder and the reflector, and FIG. 3 is a view showing how the lamp holder is attached. In FIG. 3, reference numeral 7 denotes a substrate on which device driving circuit components arranged on the back side of the reflector 3 are mounted, and 8 denotes a screw.

  As shown in FIG. 2, the assembling method of the backlight is such that the bushing-shaped portion of the lamp holder 2 is mounted and fixed in a predetermined mounting hole of the reflector 3, and the six fluorescent tubes 1 are attached to the fluorescent tube support 4 and the lamp holder 2. In addition, the lead is pulled out from the fluorescent tube electrode lead extraction hole formed on the side surface of the reflecting plate 3, and the fluorescent tubes 1 are mounted while being adjusted so as to be in the central position in the reflecting plate 3.

  In front of the backlight, the diffusion plate 5 and the liquid crystal panel 6 are arranged and fixed at a predetermined interval. The electrode lead of the fluorescent tube 1 is soldered to a backlight drive power supply output unit mounted on the substrate 7.

  In the figure, when the liquid crystal display device is operated, the fluorescent tube 1 is turned on by the driving voltage from the liquid crystal driving power supply circuit under the control of the control circuit mounted on the substrate 7, and the direct light of the emitted light and the reflecting plate 3 are turned on. Reflected light reaches the diffusion plate 5 and is diffused to uniformly irradiate the back surface of the liquid crystal panel 6.

  The liquid crystal panel is also driven by the liquid crystal drive circuit, and is displayed as a clear image by the backlight.

  In this way, by adopting the lamp holder 2, it is possible to protect against destruction due to deformation of the fluorescent tube 1, to ensure the positional accuracy of the fluorescent tube 1 array and prevent luminance unevenness on the information display surface, and By using the lamp holder 2, it is possible to prevent the luminance of the information display surface from being affected by the shade of the lamp holder 2 and the influence on the luminance unevenness.

  Since the liquid crystal display device is required to be thin, the spatial distance between the reflective plate 3 and the heat generating component disposed on the substrate 7 or the like is close, and the resin reflective plate 3 is warped under the influence of the heat generating component. (And warping also appears depending on the molding conditions of the reflector 3).

  When the lamp holder 2 is fixed to a part that is deformed in this way, the absolute position of the lamp holder 2 is shifted in a manner affected by the deformation, the fluorescent tube 1 is bent, and this also has an adverse effect such as uneven brightness and destruction of the fluorescent tube. Therefore, it is also possible to make the lamp holder 2 in the shape as shown in FIG. 3 and fix the screws 8 to the substrate 7 disposed on the back surface of the reflector 3.

  Further, there is a case where a metal is used for the reflecting plate 3, and a leak current is generated due to a delicate distance between the fluorescent tube 1 and the reflecting plate 3, so that the fluorescent tube 1 is lit one side and luminance unevenness occurs. 1 is stressed and bent in the direction of the reflector 3, so that if a sufficient distance is maintained, one-side lighting can be prevented. Therefore, the insulation distance is secured by the thickness of the base portion of the lamp holder 2. It is also possible.

  A second embodiment of the present invention will be described with reference to FIGS.

  FIG. 4 is a side view of the periphery of the liquid crystal panel and the backlight device. In FIG. 4, 9 is a lamp holder for two tubes, and has a projection at the center between the fluorescent tube 1 holding portions as shown in the detailed view of FIG. The method for assembling the backlight and the operation of the display device are the same as those in the first embodiment, and a description thereof will be omitted.

  In the direct type backlight, the diffusion plate 5 is usually arranged by opening a space of several tens of millimeters from the fluorescent tube 1 toward the screen direction. Acrylic or the like is used as the material of the diffusion plate 5 and is very sensitive to thermal expansion. When there is a temperature difference between the front and back of the diffusion plate 5, the temperature is warped in the higher direction. When used for a backlight, it is warped in the direction of the fluorescent tube 1, which also causes uneven brightness.

  Therefore, as shown in FIG. 4, it is possible to keep the distance from the diffusion plate 5 by the protrusion at the intermediate portion of the lamp holder 9 and to suppress the luminance unevenness. That is, the lamp holder 9 has both functions of preventing the fluorescent tube 1 from bending and preventing the diffusion plate 5 from warping.

  A third embodiment of the present invention will be described with reference to FIGS.

  6 and 7 are examples of lamp holder arrangements according to the present embodiment, and FIGS. 8 and 9 are examples of lamp holder arrangements that may affect display quality.

  Even in the case where a transparent lamp holder as in this embodiment is used in a backlight device having a plurality of fluorescent tubes, there is a slight effect on light dispersion and light amount reduction. When the lamp holder 2 is arranged at a position adjacent to the fluorescent tube 1 as shown in FIG. 9 or when the in-line type lamp holder 10 for holding the entire tube is used, the lamp holder can be simplified even if the assembly work is simplified. Concentration of a slight influence on the optical path by a specific area results in uneven brightness and reduced brightness.

  In the present embodiment, the mounting positions of the lamp holders 2 and 9 are arranged so as not to overlap at the positions adjacent to the longitudinal direction of the fluorescent tubes, or are staggered with respect to the arrangement direction of the fluorescent tubes 1 as shown in FIGS. By arranging in a shape, it is possible to further improve the quality against luminance unevenness by not concentrating the slight influence on the optical path by the lamp holder in a specific portion.

  As described above, the lamp holder according to the present embodiment is a lamp holder such as a fluorescent tube disposed on the reflector in the backlight device of the liquid crystal display device, and the lamp holder has an opening in a part thereof. It is made of a transparent member that has a chip-like grip shape and has flexibility.

  Further, the lamp holder according to the present embodiment has a plurality of lamp hold portions and is integrally molded.

  In addition, the lamp holder according to the present embodiment is formed by forming a protrusion on the lamp hold side to keep a distance from the diffusion plate or the light guide plate arranged in front of the fluorescent tube.

  In addition, the backlight device according to the present embodiment is a backlight device having a plurality of fluorescent tubes, and the mounting position of the lamp holder is arranged so as not to overlap with the longitudinal direction of the fluorescent tubes. It is.

  Further, the backlight device according to the present embodiment is a backlight device having a plurality of fluorescent tubes, and the mounting positions of the lamp holders are arranged in a staggered manner with respect to the arrangement direction of the fluorescent tubes.

  The present invention can be used in a non-luminous display such as a liquid crystal display device.

It is a front, a section, and a side view of a backlight and a liquid crystal display unit of an embodiment of the present invention. It is a lamp holder mounting view of an embodiment of the present invention. It is a lamp holder attachment figure of embodiment of this invention. It is a lamp holder mounting view of an embodiment of the present invention. It is a lamp holder mounting view of an embodiment of the present invention. It is a lamp holder arrangement drawing of an embodiment of the present invention. It is a lamp holder arrangement drawing of an embodiment of the present invention. It is a lamp holder arrangement example figure. It is a lamp holder arrangement example figure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fluorescent tube 2 Lamp holder 3 Reflector 4 Fluorescent tube support part 5 Diffuser plate 6 Liquid crystal panel 7 Substrate 8 Screw 9 Lamp holder for 2 tubes

Claims (4)

In a direct type backlight device having a plurality of fluorescent tubes arranged in a single row so that the longitudinal direction is substantially the same direction, and a support portion that supports the vicinity of both ends of the fluorescent tubes,
A plurality of lamp holders for supporting the fluorescent tube between the support parts,
The direct-type backlight device, wherein the lamp holders adjacent to each other in the arrangement direction of the plurality of fluorescent tubes are arranged so that positions in the longitudinal direction of the fluorescent tubes are different.   The direct-type backlight device according to claim 1, wherein the lamp holders are arranged in a staggered manner.   A liquid crystal display device comprising the direct type backlight device according to claim 1 and a liquid crystal panel. The liquid crystal display device according to claim 3, wherein the lamp holder includes a protrusion that protrudes closer to the liquid crystal panel than the plurality of fluorescent tubes.

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