JPH07270786A - Backlight unit - Google Patents

Abstract

PURPOSE:To easily attach a fluorescent lamp to a lamp house without causing the lowering of luminance and the uniformity of luminance. CONSTITUTION:The U-shaped fluorescent lamp 3 is arranged in the lamp house 15 whose upper opening is flat, and a valve locking means 17 locking the bent part 3a of the lamp 3 is disposed on the side wall of the lamp house 15. The lamp house 15 is at least formed, out of resin, and the valve locking means 17 disposed in the lamp house 15 is constituted of a pedestal 18 on which the bent part 3a of the lamp 3 is placed and a locking piece 19 which is projected toward the inside of the lamp house 15 and in which the bent part 3a is locked on the side wall adjacent to the pedestal 18, and, they are integrally formed with the lamp house 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a light-transmitting diffuser plate disposed on the opening of a flat lamp house having a light-reflecting inner wall and a light source lamp disposed therein, and disposed on the diffuser plate. The present invention relates to a direct-type backlight unit that illuminates a liquid crystal display device from the back side, and more particularly to a backlight unit in which a plurality of elongated U-shaped fluorescent lamps having a small diameter are arranged in parallel in a lamp house to achieve high brightness.

[0002]

2. Description of the Related Art A backlight unit for a liquid crystal display device of this type is a fluorescent lamp having a long and thin diameter as a light source because of a demand for a thinner device, a larger display surface, higher brightness, and lower power consumption. The mainstream is the one using an edge light type in which a fluorescent lamp is placed on the end surface of the light guide plate, and the direct type that irradiates the light of the fluorescent lamp housed in the lamp house through the light transmission diffusion plate, but is a direct type. The light extraction efficiency is higher than that of the edge light type, and is suitable for high brightness display.

Therefore, the applicant of the present invention has previously proposed the direct-type backlight unit 1 shown in FIGS.

That is, in this backlight unit 1, a plurality of elongated and small-diameter fluorescent lamps, for example, two U-shaped fluorescent lamps 3 each having a bent portion are housed in parallel in a flat lamp house 2 having an upper opening. Then, the intermediate light emitting portions 4 are arranged at substantially equal intervals and are arranged so as to be substantially parallel to the bottom surface of the lamp house 2, and the light transmitting / diffusing plate 5 is arranged above the opening of the lamp house 2.

The lamp house 2 reflects the light of the fluorescent lamp 3 toward the light transmitting / diffusing plate 5. The side wall along the optical axis of the fluorescent lamp 3 is tapered and the inner wall surface of the housing is, for example, a housing. A white coating is applied to the aluminum plate of the body or a light reflecting sheet 6 having a mirror surface is attached to form an inner wall with good light reflecting property.

The light transmitting / diffusing plate 5 is made of an acrylic resin plate or the like, and diffuses and transmits the light from the fluorescent lamp 3 to emit a uniform diffused light to the front surface side. A circuit case 7 containing a lighting circuit for lighting the fluorescent lamp 3 at a high frequency is connected to one end of the lamp house 2.

In the backlight unit 1 having such a structure, when the fluorescent lamp 3 is turned on, a part of the light is directly reflected and the rest is reflected by the light reflecting sheet 6 on the inner wall of the lamp house 2, and the light transmitting / diffusing plate 5 is used. The liquid crystal display device 8 arranged on the diffusion plate 5 is uniformly illuminated by being diffused and transmitted to the front surface side.

By the way, in such a direct-type backlight unit 1, in order to obtain a good luminance uniformity on the surface of the light transmitting / diffusing plate 5, an intermediate light emitting portion of the fluorescent lamp 3 housed in the lamp house 2 is provided. It is important that the intervals P of 4 and the height H of the fluorescent lamp 3 from the bottom surface of the lamp house 2 are accurately regulated. For this reason, in the direct-type backlight unit 1, bulb locking grooves 9 for locking the bulb end portion of the fluorescent lamp 3 are arranged at a predetermined interval P on the side wall 2a on the rear end side of the lamp house 2. At the same time, a bulb locking means 10 for locking the bent portion 3a of the fluorescent lamp 3 is provided on the side wall 2b on the tip side, and the bulb locking groove 9 and the bulb locking means 10 are provided with bulbs of the fluorescent lamp 3. By mounting the wall, the fluorescent lamp 3 is stably positioned and supported at a predetermined position in the lamp house 2.

[0009]

However, the backlight unit 1 uses a metal housing such as an aluminum plate for the lamp house 2 which houses the fluorescent lamp 3, and the fluorescent lamp 3 is fixedly supported by a fluorescent lamp. A resin tube 11 is fitted on both ends of the lamp 3 to be fitted into the bulb locking groove 9 of the lamp house 2, and the bent portion 3a is attached to the claw 12 that cuts and raises the side wall 2b of the lamp house 2 and the insulating tube 13 is attached. The structure is such that it is locked to the bulb locking means 10 formed by coating, and the work of mounting the fluorescent lamp 3 to the lamp house 2 is complicated, and a large number of assembly steps are required.

Since the bulb locking means 10 has a claw structure in which the side wall 2b of the lamp house 2 is cut and raised,
The position accuracy of the height H of the fluorescent lamp 3 from the bottom surface of the lamp house 2 was difficult to obtain. Therefore, the distance between the bottom surface of the lamp house 2 and the wall surface of the bulb of the fluorescent lamp 3 is
For example, when the thickness is set to about 1 mm and the device is thinned and the uniformity of the surface brightness is to be obtained, the lower surface of the bulb wall moves up and down and the space between the light reflection sheet 6 attached to the bottom surface of the lamp house 2 is small. There was a case where the luminance uniformity was lowered due to the deviation. Particularly, when the lower surface of the bulb wall comes into contact with the light reflection sheet 6, if the fluorescent lamp is turned on at a frequency of 15 KHz or higher, the luminance is reduced due to the leakage current passing through the bulb wall surface, and the luminance uniformity of the display surface is reduced. There was such a problem.

Therefore, the present invention has been made in view of the problem in mounting the fluorescent lamp in the above-mentioned conventional backlight unit, and the fluorescent lamp can be easily and accurately assembled in the lamp house, and the brightness reduction and the brightness uniformity can be achieved. It is an object of the present invention to provide a backlight unit in which the device can be made thinner without causing the deterioration of the device.

[0012]

Therefore, in the backlight unit of the present invention, the U-shaped fluorescent lamp is arranged in the flat lamp house having the upper opening, and the bent portion of the U-shaped fluorescent lamp is provided on the side wall of the lamp house. A lamp locking means for locking the lamp housing is provided, the lamp house is made of at least resin, and the bulb locking means arranged in the lamp house has a bent portion of the U-shaped fluorescent lamp. A pedestal to be placed and a locking piece that projects toward the inside of the lamp house on the side wall adjacent to this cradle and that has a bent part locked, each integrally formed with the lamp house Is. Further, an opening is formed in the pedestal portion facing the locking piece.

[0013]

[Function] Since the valve locking groove and the valve locking means are integrally formed by resin molding, there is no need to fit resin tubes on both ends of the fluorescent lamp or to cover the locking claws with insulating tubes, etc. . Further, since the pedestal of the bulb locking means is formed at a predetermined height on the bottom surface of the lamp house, the height H position from the bottom surface of the fluorescent lamp is always supported at a constant height.
Further, since the lamp house is formed by resin molding, even if a high frequency voltage is applied, it is possible to prevent a leak current leaking to the lamp house through the wall surface of the bulb. Since the lamp house has an opening in the pedestal part facing the locking piece,
The resin can be molded by a simple mold, and the heat in the lamp house can be radiated from the opening, so that the efficiency reduction of the fluorescent lamp is reduced.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing a main structure of a backlight unit according to the present invention.

Similar to the backlight unit 1, the backlight unit 14 also has a plurality of bulb locking grooves 16 provided at predetermined intervals on a side wall 15a on the rear end side of the flat lamp house 15 having an upper opening. The rear end of the U-shaped fluorescent lamp 3 of the book is mounted, and the bent portion 3a on the front end side is attached to the lamp house 15.
It is locked by the bulb locking means 17 disposed inside, and the intermediate light emitting parts 4 are arranged in parallel at substantially equal intervals.
It is stored substantially parallel to the bottom surface of the
A light transmission diffusion plate is arranged on the opening of the lamp house 15,
It is a backlight unit of a direct-irradiation type structure that uniformly illuminates a liquid crystal display device arranged on the upper surface from the back surface.

In this backlight unit 14,
The main difference from the backlight unit 1 is that the lamp house 15 is formed by resin molding, and the bulb locking means 17 that locks the bent portion 3a of the fluorescent lamp 3 inside the lamp house 15 is provided with a lamp. Cradle 18 that receives the bottom side
And an elastic locking piece 19 that is locked to the upper surface side of the bulb, which are resin-molded integrally with the lamp house 15. The same components are designated by the same reference numerals as in FIGS. 3 to 6. ing.

That is, the lamp house 15 is a resin molded product,
A side wall along the optical axis of the fluorescent lamp 3 is formed in a flat shape with a tapered upper surface, and a bulb locking groove 16 for mounting the U-shaped fluorescent lamp 3 is formed on a rear side wall 15a. By inserting both ends of the fluorescent lamp 3 into the mounting groove 16, the intermediate light emitting parts 4 are arranged in parallel at desired intervals. Then, in the vicinity of the bottom surface of the side wall 15b on the tip end side, as shown in an enlarged view of FIG. 2, for example, a pedestal 18 on which the bottom surface is raised by a predetermined height H and on which the valve lower surface is placed,
A locking piece 19 extending from the side wall 15b to a position above the pedestal 18 toward the inside of the lamp house and locked to the upper surface of the bulb.
When the bent portion 3a of the U-shaped fluorescent lamp 3 is pushed onto the pedestal 18 as indicated by the arrow, the tip portion of the locking piece 19 responds and the valve locking means 17 is formed. It is configured to hug a wall.

In the backlight unit 14 having such a structure, both ends of the U-shaped fluorescent lamp 3 are mounted in the bulb locking groove 16 of the lamp house 14, and the bent portion 3a on the tip side is pushed into the bulb locking means 17. Thus, the fluorescent lamp 3 can be easily attached to the lamp house 15.

In this case, in the bulb locking means 17 in the lamp house 15 that supports the bent portion 3a of the fluorescent lamp 3, the pedestal 18 is formed with a step difference from the bottom surface of the lamp house 15 by a predetermined height H. Therefore, the height H from the bottom surface of the intermediate light emitting portion 4 is regulated, and the interval with the light reflection sheet 6 attached to the bottom surface of the lamp house 14 is kept constant,
A decrease in brightness uniformity is prevented. Further, the pedestal 18 facing the locking piece 19 is provided with a through hole (opening 18
Since (a) is formed, resin molding can be performed with a simple mold, and heat in the lamp house can be released through the opening 18a, so that the efficiency decrease of the fluorescent lamp can be reduced.

In the above embodiment, the pedestal 18 is formed on the bottom surface of the lamp house 15 near the side wall 15b, and the locking wall 19 is extended from the side wall 15b to hold the bulb wall. The pedestal 18 can be arranged anywhere on the bottom surface of the lamp house 15 on which the lower surface of the bulb of the intermediate light emitting unit 4 is placed. Also, the locking piece 19
Although it is configured to extend from the side wall 15b of the lamp house 15, it is also possible to extend from the bottom surface of the lamp house 15.

[0022]

As described in detail above, according to the present invention,
When installing the fluorescent lamp in the lamp house, it is not necessary to fit resin tubes on both ends of the bulb or to cover the claws formed by cutting and raising the side wall with the insulating tube, and mount the fluorescent lamp on the pedestal of the bulb locking means. It can be mounted in one-touch type by pushing the tip of the bulb on top, and the work of mounting the fluorescent lamp in the lamp house becomes extremely easy.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main configuration of a backlight unit of the present invention.

FIG. 2 is a partially enlarged cross-sectional view taken along the line DD of FIG.

FIG. 3 is a perspective view showing a configuration example of a conventional backlight unit.

FIG. 4 is a sectional view taken along line AA of FIG.

5 is a sectional view taken along the line BB in FIG.

FIG. 6 is a sectional view taken along the line CC of FIG.

[Explanation of symbols]

 3 Fluorescent lamp 4 Intermediate light emitting part 14 Backlight unit 15 Lamp house 16 Bulb locking groove 17 Bulb locking means 18 Cradle 19 Locking piece

Claims (2)

[Claims] 1. A U-shaped fluorescent lamp is arranged in a flat lamp house having an upper opening, and a U-shaped fluorescent lamp is provided on a side wall of the lamp house.
A bulb locking means for locking the bent portion of the fluorescent lamp is disposed, the lamp house is made of at least resin, and the valve locking means disposed in the lamp house is the U-shaped. The fluorescent lamp includes a pedestal on which the bent portion is placed, and a side wall adjacent to the pedestal, which includes a locking piece that projects toward the inside of the lamp house and has the bent portion locked. A backlight unit characterized by being integrally formed. 2. The backlight unit according to claim 1, wherein an opening is formed in a pedestal portion facing the locking piece.