JP2008021564A - Backlight device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display panel, an optical sheet set arranged and installed between the liquid crystal display panel and backlight units, and a support means which does not depend on individual components in order to support a light diffusion plate in a thin type display device which has the liquid crystal display panel as a screen display element. <P>SOLUTION: On both upper and lower end front faces of a light-emitting tube clip cover 22 arranged and installed along both right and left short sides of a backlight chassis 9 constituting a backlight device of the thin type display device which has the liquid crystal display panel as the screen display element, a support protrusion is integrally formed with the light-emitting tube clip cover, or both upper and lower ends of the light-emitting tube clip cover 22 are extended and stretched in the right-angle direction along long sides of the backlight chassis 9, the support protrusion 22d is integrally formed with the light-emitting tube clip cover 22 in the extended and stretched part front face of the light-emitting tube clip cover 22, and the optical sheet set 4 and the light diffusion plate 5 are supported. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a structure of a backlight device of a thin display device using a liquid crystal display panel as a screen display element.

FIG. 2 is an exploded perspective view for explaining an outline of the configuration of an optical system unit in a liquid crystal television having a liquid crystal display panel as a screen display element. In FIG. 2, 2 is a liquid crystal display panel, 4 is an optical sheet set composed of a plurality of film-like optical sheets, 5 is a light diffusion plate, 6 is a plurality of arc tubes constituting the backlight unit 3, and 9 is It is the backlight chassis which comprises a backlight unit.

A backlight unit for irradiating the liquid crystal display panel with light is disposed on the back of the liquid crystal display panel of a thin display device using the liquid crystal display panel as a screen display element. Furthermore, between the liquid crystal display panel and the backlight unit, advanced light control such as light reflection, polarization, refraction, light diffusion, etc., for improving image quality such as high brightness and uniform surface brightness of the liquid crystal display screen. An optical sheet set composed of a plurality of film-like optical sheets provided with means such as forming a large number of microlens arrays on the surface by using a technique is disposed.

In order to obtain desired optical characteristics, the optical sheet set and the light diffusing plate have different constituent materials and thickness for each optical sheet constituting the optical sheet set. Accordingly, since each optical sheet constituting the optical sheet set has a different expansion coefficient, the optical sheet set may bend and wrinkle with changes in temperature and humidity during use of a thin display device such as a liquid crystal television. There arises a problem that surface uniformity of characteristics deteriorates. In order to prevent the occurrence of this problem, it is necessary for the optical sheet surfaces constituting the optical sheet set to be slidable with each other, and the periphery of the optical sheet set cannot be firmly fixed and locked to the structure. .

An example of a conventional technique for supporting an optical sheet set will be described with reference to FIG. FIG. 5A is an exploded perspective view of the backlight unit, and FIG. 5B is an enlarged view of a broken line portion in FIG. 5, showing conventional support means for the optical sheet set and the light diffusing plate. As shown in FIGS. 5A and 5B, the light reflecting plate 7 and both ends of the plurality of arc tubes 6 are sandwiched between inner surfaces of the bottom portion of the backlight chassis 39 that is open and has a box shape. An arc tube holder 8 is provided. In order to lock the light reflector 7 to the bottom inner surface of the backlight chassis 39, the arc tube clip cover 32 is placed on the bottom inner surface of the backlight chassis 39 at a position covering the arc tube holders 8 at both ends of the arc tube 6. It is locked. Further, the arc tube clip cover 32 is provided with a positioning projection 32a for regulating the position of the optical sheet set and the light diffusion plate in the longitudinal direction.

The optical sheet set and the light diffusing plate (not shown) are arranged in a state where the periphery is placed on a flat portion formed by the box-like edge upper surface of the backlight chassis 39 and the arc tube clip cover 32 upper surface. As shown in FIG. 5 (b), an invention in which a support 33, which is a dedicated individual part, is fitted into an insertion hole 39a formed in front of the upper and lower long sides of a box-shaped backlight chassis 39 whose one surface is released. It is made by patent document 1. Thereby, the position of the optical sheet set and the light diffusing plate is regulated by the positioning protrusions 32 a arranged in the left and right directions, and the position in the short direction is regulated by the support 33.
Japanese Patent Application No. 2006-013136

In a thin display device using a liquid crystal display panel as a screen display element, optical characteristics due to generation of deflection and wrinkles of an optical sheet set composed of a plurality of film-like sheets disposed between the liquid crystal display panel and a backlight unit In order to prevent the deterioration of the surface uniformity, it is necessary that the surfaces of the optical sheets be slidable with each other, and the periphery of the optical sheet set cannot be firmly fixed and locked to the structure. As a prior art example of the locking means of the optical sheet set, as seen in Patent Document 1, a support body as a dedicated individual part is used as a front surface on the upper and lower long sides of a box-shaped backlight chassis with one surface released. Although the invention has been made to fit into the insertion hole drilled in, there are economic disadvantages such as investment in a mold for molding a support, which is a dedicated individual part, and an increase in part cost.

In addition, labor costs for assembling a plurality of support bodies, which are dedicated individual parts, to the front surfaces of the upper and lower long sides of the backlight chassis are not only incurred, but also for indirect work such as arranging and managing the support parts. Labor costs are also incurred.

In the present invention, in the backlight device, the arc tube clip cover that covers the arc tube electrode portion is integrally provided with a projection that restricts at least the vertical movement of the diffuser plate and the optical sheet constituting the backlight device. It is formed.

In the backlight device according to the present invention, the backlight device has a backlight chassis, and the upper and lower ends of the arc tube clip cover disposed along the left and right short sides of the backlight chassis are connected to the backlight chassis. A projection is formed integrally with the arc tube clip cover on the front surface of the elongated portion of the arc tube clip cover.

Further, in the backlight device according to the present invention, a second protrusion for restricting the movement of the diffusion plate and the optical sheet in the left-right direction is integrally formed on the upper surface of the arc tube clip cover. It is characterized by that.

In the backlight device according to the present invention, a locking claw for locking the diffusion plate and the optical sheet is provided inside both the upper and lower protrusions of the arc tube clip cover.

Further, in the backlight device according to the present invention, the space between the diffusion plate and the optical sheet formed by the locking claws and the upper surface of the arc tube clip cover can slide the diffusion plate and the optical sheet. It is characterized by having a proper size.

Furthermore, in the backlight device according to the present invention, the size of the gap is smaller than the height of the second protrusion.

According to the present invention, a support that is a dedicated component for supporting the optical sheet set and the light diffusing plate is not necessary, and it is possible to reduce the number of components and the number of assembly work steps. Further, since the locking claw for locking the optical sheet set and the light diffusing plate is provided, the optical sheet set and the light diffusing plate are stably supported. It becomes possible.

Hereinafter, a case where an embodiment of the present invention is applied to a liquid crystal television will be described with reference to the drawings. FIG. 1 is a front view of a liquid crystal television. In FIG. 1, 1 is a front cabinet and 2 is a liquid crystal display panel for image display.

Next, an outline of the configuration of the optical system unit inside the liquid crystal television will be described based on the exploded perspective view of FIG. On the back side of the LCD panel 2, advanced light control technologies such as light reflection, polarization, refraction, and light diffusion are used to improve image quality such as high brightness and uniform screen brightness. An optical sheet set 4 composed of a plurality of film-like optical sheets having means such as forming a large number of microlens arrays on the surface and a light diffusion plate 5 are disposed. Further, behind the light diffusing plate 5, a backlight unit 3 for irradiating light to the back of the optical sheet set 4 and the liquid crystal display panel 2 is disposed. The backlight unit 3 is disposed in the backlight chassis 9. A number of arc tubes 6 are arranged and configured.

FIG. 3 is an enlarged perspective view of the vicinity of the arc tube clip cover 12 of the backlight unit showing the first embodiment of the present invention. An arc tube holder 8 is locked to the inner bottom surface of the backlight chassis 9, and ends of a large number of arc tubes 6 are held by arc tube clips 8 a formed integrally with the arc tube holder 8. The arc tube holder 8 including the arc tube clip 8a in order to prevent dust from adhering to the electrode terminal 6a of the arc tube 8 to which a high voltage is applied and to use the uniform luminance portion of the arc tube 6 as an effective luminance region. The whole and the electrode terminal portion 6 a of the arc tube 6 are covered with the arc tube clip cover side surface 12 b constituting the arc tube clip cover 12.

The lower and upper (not shown) portions of the light reflecting plate 7 shown in FIG. 3 radiate radially from the tube axis of the arc tube 6 and emit light bundles toward the lower and upper sides (not shown) of the light reflecting plate 7. In order to refract and reflect a liquid crystal display panel (not shown) disposed on the front surface of the light reflecting plate 7, the rising portion 7 a is a bottom surface of the light reflecting plate 7 like the lower side of the light reflecting plate 7 shown in FIG. The rising portion 7a of the light reflecting plate 7 is pressed by the light reflecting plate rising surface pressing portion 12a constituting the arc tube clip cover 12 so that the bending angle is not restored. ing.

As shown in FIG. 3, a first support projection 12 d constituting the arc tube clip cover 12 is integrally formed at the lower end of the arc tube clip cover 12, and the first support projection 12 d is formed on the light diffusion plate 5. The lower end of the optical sheet set 4 is supported. A plurality of second support protrusions 12e constituting the arc tube clip cover 12 are integrally formed on the arc tube clip cover upper surface 12c. The second support protrusions 12e regulate the positions of the left and right ends of the light diffusion plate 5 and the optical sheet set 4. In addition, since the light diffusing plate 5 and the optical sheet set 4 expand and contract depending on the temperature and humidity, the region of the arrangement of the light diffusing plate 5 and the optical sheet set 4 regulated by the first support protrusion 12d and the second support protrusion 12e is A region slightly wider than the dimensions of the light diffusion plate 5 and the optical sheet set 4 is secured.

In order to obtain desired optical characteristics, the optical sheet set 4 and the light diffusing plate 5 have different constituent materials and thicknesses of the light diffusing plate 5 and the optical sheet set 4 for each optical sheet. Each sheet set 4 has a different coefficient of thermal expansion and moisture absorption characteristics, and due to temperature and humidity changes that occur during use of the liquid crystal television, the optical sheet set 4 is subjected to surface uniformity due to the occurrence of deflection and wrinkles. And the peripheral portion of the light diffusion plate 5 and the optical sheet set 4 cannot be firmly fixed and locked to the structure.

In the present invention, the left and right edges of the back surface of the light diffusing plate 5 and the optical sheet set 4 are disposed on the left and right ends of the inner bottom surface of the backlight chassis 9 on the one of the arc tube clip covers 12. Each optical member constituting the light diffusion plate 5 and the optical sheet set 4 is brought into contact with the second support protrusion 12e and supported at the lower end by the first support protrusion 12d formed integrally with the arc tube clip cover 12. The seat surfaces can slide freely with respect to each other, and the occurrence of deflection and wrinkles can be avoided.

FIG. 4 is an enlarged perspective view of the vicinity of the arc tube clip cover 22 showing the second embodiment of the present invention. An arc tube holder 8 is locked to the inner bottom surface of the backlight chassis 9, and ends of a large number of arc tubes 6 are held by arc tube clips 8 a formed integrally with the arc tube holder 8. The arc tube holder 8 including the arc tube clip 8a in order to prevent dust from adhering to the electrode terminal 6a of the arc tube 8 to which a high voltage is applied and to use the uniform luminance portion of the arc tube 6 as an effective luminance region. The whole and the electrode terminal portion 6 a of the arc tube 6 are covered with the arc tube clip cover side surface 22 b constituting the arc tube clip cover 22, and the rising portion 7 a of the light reflection plate 7 is covered with the arc tube clip cover 22. Is pressed by the light reflecting plate rising surface pressing portion 22a.

In order to refract and reflect the light beam directed toward the lower side and the upper side (not shown) of the light reflecting plate 7 to a liquid crystal display panel (not shown) disposed on the front surface of the light reflecting plate 7, the rising portion 7a is provided with the light reflecting plate. 7 is bent at an obtuse angle from the bottom surface.

As shown in FIG. 4, at the lower end of the arc tube clip cover 22, the light reflecting plate rising surface pressing portion 22 a and the first support protrusion 22 d constituting the arc tube clip cover 22 are provided with the light diffusion plate 5 and the optical sheet set. 4 extending in the direction of the vertical center line. The first support protrusions 22d support the light diffusion plate 5 and the lower end of the optical sheet set 4, and the plurality of second support protrusions 22e provided on the arc tube clip cover upper surface 22c The position of the left and right ends of the optical sheet set 4 is regulated.

Since the light diffusing plate 5 and the optical sheet set 4 expand and contract depending on temperature and humidity, the region of the light diffusing plate 5 and the optical sheet set 4 that is regulated by the first support protrusion 22d and the second support protrusion 22e is as follows. A region slightly wider than the dimensions of the light diffusion plate 5 and the optical sheet set 4 is secured.

In the present invention, by extending the light reflection plate rising surface pressing portion 22a and the first support protrusion 22d constituting the arc tube clip cover 22 in the vertical center line direction of the light diffusion plate 5 or the optical sheet set 4, It is possible to support a portion near the center of gravity of the light diffusing plate 5 or the optical sheet set 4, thereby improving the support strength and contributing to improvement in reliability.

5A and 5B are views showing a third embodiment of the present invention. FIG. 5A is an enlarged perspective view in the vicinity of the arc tube clip cover 13, and FIG. 5B is an arc tube viewed from the direction of arrow A. FIG. 4 is a side view of the clip cover 13. FIG. An arc tube holder 8 is locked to the inner bottom surface of the backlight chassis 9, and ends of a large number of arc tubes 6 are held by arc tube clips 8 a formed integrally with the arc tube holder 8. The arc tube holder 8 including the arc tube clip 8a in order to prevent dust from adhering to the electrode terminal 6a of the arc tube 8 to which a high voltage is applied and to use the uniform luminance portion of the arc tube 6 as an effective luminance region. The whole and the electrode terminal portion 6 a of the arc tube 6 are covered with the arc tube clip cover side surface 13 b constituting the arc tube clip cover 13, and the rising portion 7 a of the light reflection plate 7 is covered with the arc tube clip cover 13. Is pressed by the light reflecting plate rising surface pressing portion 13a.

In order to refract and reflect the light beam directed toward the lower side and the upper side (not shown) of the light reflecting plate 7 to a liquid crystal display panel (not shown) disposed on the front surface of the light reflecting plate 7, the rising portion 7a is provided with the light reflecting plate. 7 is bent at an obtuse angle from the bottom surface.

As shown in FIG. 5 (a), the lower end of the arc tube clip cover 13 is provided with a first support protrusion 13d constituting the arc tube clip cover 13, and further, the inner surface of the light reflecting plate rising surface pressing portion 13a. Is provided with an optical sheet pressing claw 13f. The first support protrusion 13d supports the light diffusing plate 5 and the lower end of the optical sheet set 4, and the optical sheet pressing claw 13f moves or flexes the light diffusing plate 5 and the optical sheet set 4 toward the liquid crystal panel (not shown). It will prevent you from sneaking. On the other hand, the plurality of second support protrusions 13 e provided on the arc tube clip cover upper surface 13 c regulate the positions of the left and right ends of the light diffusion plate 5 and the optical sheet set 4. Note that when the deflection of the optical sheet set 4 becomes extremely large and comes into contact with the liquid crystal panel surface positioned in front, a Newton ring stripe pattern appears on the screen, which may hinder viewing.

Since the light diffusing plate 5 and the optical sheet set 4 expand and contract depending on the temperature and humidity, the region of the light diffusing plate 5 and the optical sheet set 4 that is regulated by the first support protrusion 13d and the second support protrusion 13e is as follows. A region slightly wider than the dimensions of the light diffusion plate 5 and the optical sheet set 4 is secured. The gap between the light diffusion plate 5 and the optical sheet set 4 formed by the optical sheet pressing claw 13f and the arc tube clip cover upper surface 13c is substantially the same as the total thickness of the light diffusion plate 5 and the optical sheet set 4. In addition, the light diffusing plate 5 and the optical sheet set 4 are set so as to have dimensions allowing free sliding.

The height of the second support projection 13e from the arc tube clip cover upper surface 13c is set to be higher than that of the optical sheet pressing claw 13f. Even when tilted downward, the light diffusing plate 5 and the optical sheet set 4 do not move beyond the second support protrusion 13e.

The light diffusing plate 5 and the optical sheet set 4 are loaded into the arc tube clip cover 13 in a state where the arc tube clip cover 13 is fixed with screws or the like at predetermined positions on the left and right ends of the backlight chassis 9. First, after the lower end of the diffusing plate 5 is slid inside the optical sheet pressing claw 13f on the lower side of the arc tube clip cover 13, the diffusion plate 5 is placed on the optical sheet pressing claw 13f on the upper side of the arc tube clip cover 13. In this state, the upper end of the optical sheet pressing claw 13f is opened upward with a finger or a tool, and the upper end of the diffusion plate 5 is dropped into the optical sheet pressing claw 13f. Next, the optical sheet set 4 is loaded one by one or in a state in which a plurality of optical sheet sets 4 are combined in the procedure of loading the diffusion plate 5.

Note that the loading method is not limited to this method, and a method of loading the diffusion plate 5 into the optical sheet pressing claw 13f by pushing the diffusion plate 5 with a finger, or bending the diffusion plate 5 or the optical sheet set 4 to be curved. It is also possible to load it inside the optical sheet pressing claw 13f. The light reflecting plate rising surface pressing portion 13a and the first support protrusion 13d are thin and flexible, and various loading methods are possible.

In the present invention, the optical sheet pressing claw 13f is provided at an appropriate height from the arc tube clip cover upper surface 13c inside the light reflecting plate rising surface pressing portion 13a constituting the arc tube clip cover 13, so that the light diffusing plate is provided. 5 and the optical sheet set 4 can be freely slid, and can be prevented from moving and bending toward the liquid crystal panel. Further, by setting the height of the second support protrusion 13e to an appropriate height, the light diffusing plate 5 and the optical sheet set 4 can be stably supported even when the liquid crystal television is tilted in various directions. It becomes possible, and it becomes possible to prevent the trouble of television viewing.

In the third embodiment, the optical sheet pressing claw 13f is provided inside the light reflecting plate rising surface pressing portion 13a. However, the upper and lower ends of the arc tube clip cover 13 described as the first support protrusion 13d are described. If it is inside the start-up portion, the position to be provided is not restricted. In the third embodiment, the application of the first embodiment has been described. However, the application to the second embodiment is naturally possible.

It is a front view of the liquid crystal television concerning embodiment of this invention. It is a disassembled perspective view which shows the structure outline | summary of the optical system unit inside the liquid crystal television concerning embodiment of this invention. FIG. 3 is an enlarged perspective view of the vicinity of the arc tube clip cover of the backlight unit according to the first embodiment of the present invention. It is an expansion perspective view of the arc tube clip cover vicinity which shows the 2nd Embodiment of this invention. It is a figure which shows the 3rd Embodiment of this invention, (a) is an expansion perspective view of arc tube clip cover vicinity, (b) is a side view of A direction view. The figure of a prior art is shown, (a) is a disassembled perspective view of a backlight unit, (b) is an enlarged view of the broken line part in (a), and shows the conventional support means of an optical sheet set and a light diffusing plate. Yes.

Explanation of symbols

1: Front cabinet 2: Liquid crystal display panel 3: Backlight unit 4: Optical sheet set 5: Light diffusing plate 6: Light emitting tube 6a: Electrode terminal 7: Light reflecting plate 7a: Rising part 8: Light emitting tube holder 8a: Light emitting tube Clip 9: Backlight chassis 12: Arc tube clip cover 12a: Light reflector rising surface pressing portion 12b: Arc tube clip cover side surface 12c: Arc tube clip cover top surface 12d: First support projection 12e: Second support projection 13: Light emission Tube clip cover 13a: Light reflector rising surface pressing portion 13b: Arc tube clip cover side surface 13c: Arc tube clip cover top surface 13d: First support projection 13e: Second support projection 13f: Optical sheet presser claw 22: Arc tube clip cover 22a: Light reflector rising surface pressing portion 22b: Arc tube clip cover Side 22c: luminous tube clip cover upper surface 22 d: first support protrusions 22e: Second support projection 32: arc tube clip cover 33: support 39: the backlight chassis 39a: insertion hole

Claims (6)

In the backlight device, the arc tube clip cover that covers the arc tube electrode portion is integrally formed with a projection that restricts at least the vertical movement of the diffuser plate and the optical sheet constituting the backlight device. A backlight device. The backlight device according to claim 1, wherein the backlight device has a backlight chassis, and the upper and lower ends of the arc tube clip cover disposed along the left and right short sides of the backlight chassis are connected to the backlight. A backlight device, characterized in that it extends in a perpendicular direction along the upper and lower long sides of the chassis, and a projection is formed integrally with the arc tube clip cover on the front surface of the extension portion of the arc tube clip cover. 3. The backlight device according to claim 1, wherein a second protrusion that restricts movement of the diffuser plate and the optical sheet in the left-right direction is integrally formed on the upper surface of the arc tube clip cover. A backlight device characterized by being formed. 4. The backlight device according to claim 1, wherein a locking claw for locking the diffusion plate and the optical sheet is provided inside both the upper and lower protrusions of the arc tube clip cover. Light equipment. 5. The backlight device according to claim 4, wherein the diffusion plate and the optical sheet are slid in a gap formed by the locking claws and the upper surface of the arc tube clip cover in which the diffusion plate and the optical sheet are sandwiched. A backlight device, characterized in that it has a possible size. 6. The backlight device according to claim 5, wherein the size of the gap is smaller than the height of the second protrusion.

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