JPH0464139B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a flat fluorescent lamp suitable for backlighting of liquid crystal display devices such as liquid crystal TVs.

(b) Prior Art In recent years, in order to make TV receivers thinner, liquid crystal TVs using liquid crystal display devices have been developed.

Since the liquid crystal panel used in this liquid crystal TV does not emit light by itself, it is necessary to use some kind of light source as a backlight to transmit light through the liquid crystal to obtain a certain level of brightness.

Normally, the following conditions are required for the back light.

It must be a flat light source that matches the size of the LCD TV (3:4 aspect ratio).

The brightness on the light source surface must be uniform.

Good luminous efficiency.

Low temperature rise.

Good color rendering.

Among these conditions, especially small size and
This is an essential condition for realizing high-definition LCD TVs.

Conventionally, it has been considered to arrange a plurality of cylindrical fluorescent lamps on the back surface of the liquid crystal panel as the backlight, but this is not very preferable because it causes uneven brightness of the plurality of fluorescent lamps on the screen.

It is also conceivable to use a flat fluorescent lamp such as that disclosed in Japanese Utility Model Application Publication No. 54-111985, and with this flat fluorescent lamp, brightness unevenness can be improved to some extent compared to the above-mentioned method.

However, the above-mentioned flat type fluorescent lamp requires a thick flat glass plate to prevent implosion due to atmospheric pressure, which hinders miniaturization and weight reduction.

On the other hand, the flat type fluorescent lamp according to the above-mentioned publication is usually composed of a dish-shaped glass 100 and a flat glass 200, as shown in FIG. This dish-shaped glass is usually press-molded, and its side wall 100a
is rounded and sloped at the end. Therefore, the plate-shaped electrode 300 is attached to the side wall 10.
When the electrode 300 is placed close to the side wall 100a, a dead space is generated between the side wall 100a and the electrode 300. Furthermore, a flat glass 200 is provided at the lower end of the side wall 100a.
A flange portion 100b for joining is formed.

For example, for a 5-inch LCD TV, the size is
154mm (W) x 112mm (H) x 18mm (T) (However,
The glass thickness is 4mm (not including the chip tube and lead piece), and the weight is 450g.

Therefore, there are disadvantages in that the area of the entire flat fluorescent lamp becomes unnecessarily large with respect to the effective light emitting area determined by the distance between the electrodes 3, 3, and the weight becomes heavy.

In addition, JP-A-60-189154 discloses a flat surface having a pair of flat glasses and a pair of electrodes facing each other in a direction perpendicular to the facing direction of the flat glasses, the inside of which is partitioned by reinforced glass. type fluorescent lamp is described. However, in a flat type fluorescent lamp having this structure, there is a problem in that the discharge is concentrated in the center of the area partitioned by the reinforced glass, resulting in non-uniform brightness.

(c) Problems to be solved by the invention The present invention has been made in view of the above points,
To provide a flat fluorescent lamp suitable for a backlight of a liquid crystal TV, which can be made small and lightweight, and has uniform brightness throughout.

(d) Means for solving the problems The present invention consists of a pair of flat glasses, a frame glass disposed between the flat glasses, and an exhaust pipe disposed in a part of the frame glass, A pair of discharge electrodes facing each other in a direction perpendicular to the facing direction of the pair of flat glasses are disposed inside, and the distance between the pair of flat glasses is approximately parallel to a line connecting the pair of discharge electrodes. In the flat fluorescent lamp, the pair of discharge electrodes is composed of a rear wall, a pair of side walls, an upper wall, and a lower wall, and the cross section and longitudinal section thereof are A pair of auxiliary electrodes each having a U-shape in cross section are mounted between the upper and lower walls of the pair of discharge electrodes so that side walls are located on both sides of the reinforcing glass.

(E) Effects According to the present invention, the area of the entire flat fluorescent lamp relative to the effective light emitting area is reduced by the above-mentioned means.

(F) Embodiment An embodiment of the present invention will be described below with reference to the drawings.

Figure 1 A, B, and C are a plan view, an A-A' cross-sectional view, and a B--
This is a sectional view of B', in which 1 and 2 are a pair of upper and lower flat glasses whose inner surfaces are coated with fluorescent paint, 3 is the periphery of the upper and lower flat glasses, and the space between the upper and lower flat glasses is maintained at a predetermined distance. 4, 4 are a pair of discharge electrodes, 5, 5 are auxiliary electrodes connected to this discharge electrode, 6, 6 are first lead pieces that are connected to this discharge electrode and protrude to the outside; In addition to its physical function, it also has a function of mechanically supporting the discharge electrodes 4, 4. Reference numerals 7 and 7 designate second lead pieces that are connected to the discharge electrode but do not protrude to the outside, and serve only to mechanically support the discharge electrode. 8, 8... are welded onto the lower flat glass 2 by frit glass or the like and are in contact with the lower surface of the upper flat glass 1, and the discharge electrodes 4,
4 is a bar-shaped reinforced glass arranged in a direction perpendicular to the frame glass 3, and its cross section is trapezoidal, and its height is set to be the same as the frame glass 3. This reinforced glass is installed to partition the inside of the fluorescent lamp, but if the partitioned space is completely sealed, it will not be possible to exhaust the air.
is formed. Fluorescent paint is also applied to the side surfaces of this reinforced glass. Reference numeral 10 is a chip tube whose tip is sealed by heat welding after evacuating the air inside the fluorescent lamp and allowing argon gas and mercury to flow therein.

The discharge electrode 4 is connected to the rear wall 4 as shown in FIG.
a, a pair of side walls 4b, 4b, an upper wall 4c and a lower wall 4
d, and its cross section and longitudinal section are respectively U-shaped. Further, the amount of protrusion of the side walls 4b, 4b is made larger than the amount of protrusion of the upper and lower walls 4c, 4d. A pair of auxiliary electrodes 5, 5 each having a U-shaped cross section are mounted between the upper and lower walls 4c, 4d. That is, the rear wall 5a of this auxiliary electrode is attached to the rear wall 4a of the discharge electrode by welding or the like. In this state, the side walls 5b, 5b of this auxiliary electrode are located on both sides of the reinforcing glass 8, and the upper and lower walls 4c,
4d, but the amount of protrusion is smaller than the side walls 4b, 4b of the discharge electrode.

The distance between the opposing electrodes in the flat fluorescent lamp of this embodiment is such that the side walls 4b, 4b... of each discharge electrode 4, 4 and the side walls 5b, 5b... of the auxiliary electrodes 5, 5... are shorter than other parts. Therefore, due to the so-called "Patsien's law", the discharge starting voltage at each side wall is lower than at other parts.

Furthermore, since each of the side walls has a protruding shape, the electric field tends to concentrate thereon.

For this reason, the structure of the electrode is such that discharge is more likely to occur on each of the side walls than on other parts.

Therefore, within the three portions partitioned by the reinforcing glasses 8, 8..., the side walls 4b, 4b... of the discharge electrodes 4, 4 and the side walls 5 of the auxiliary electrodes 5, 5...
b, 5b, . . . can prevent the discharge from concentrating in the center and becoming non-uniform, and the discharge can be made uniform over the entire surface of the fluorescent lamp.

Further, FIGS. 3A and 3B show another embodiment of the reinforcing glass, in which the reinforcing glass in this embodiment has a cylindrical shape, and the inner peripheral surface thereof is coated with fluorescent paint. Furthermore, a fluorescent paint may also be applied to the outer peripheral surface.

Note that the reinforced glass may have a rectangular or square cross section.

Next, FIGS. 4A and 4B show other embodiments of the present invention.

In this embodiment, spherical glass beads 11, 11, . . . are used as the reinforcing glass, and the diameter thereof is made equal to the height of the frame glass 3. The glass beads are adhered to one of the upper and lower flat glasses 1 and 2. Further, the discharge electrodes 4, 4 are the same as those in FIG. 2, but no auxiliary electrodes are provided.

The above-mentioned glass beads are commercially available in various diameters at low cost, and one can be selected from among them. Further, manufacturing can be performed extremely easily and with high dimensional accuracy.

Next, FIGS. 5A and 5B and FIG. 6 show still other embodiments of the present invention.

In this embodiment, semicircular glass protruding pieces 12, 12, . . . are used as the reinforcing glass. This protruding piece has the same height as the frame glass 3, and is integrally formed on the lower flat glass 2 by press molding, as shown in FIG.

Further, the protruding piece 12 may be a conical piece press-molded onto the lower flat glass 2 as shown in FIG.

According to this embodiment, since the reinforcing glass is integrally press-molded with the lower flat glass in advance, the number of parts and the number of assembly steps can be reduced.

Further, FIGS. 8A, 8B and 8C show other embodiments of the present invention.

In this embodiment, the first and second lead pieces 6,
6, 7, 7 are the side walls 4b, 4 of the discharge electrodes 4, 4, respectively.
b..., and both lead pieces are pulled out in parallel with the discharge electrode. That is, the pair of first lead pieces are pulled in the same direction, and this direction is the same as the direction in which the tip tube 10 projects.

Therefore, according to this embodiment, since the reed pieces and the tip tube protrude in the same direction, the area occupied by the flat fluorescent lamp is made smaller than in the cases of FIGS. 1, 4, and 5. be able to.

The flat fluorescent lamp in this example has a 5-inch liquid crystal display.
It is for TV and its size is 144mm (W) x 99mm.
(H) x 17mm (T) (however, the glass thickness is 4mm, not including the chip tube and reed piece), and the weight is 360g, making it smaller and lighter than the conventional example shown in Figure 9.

(G) Effects of the Invention As described above, according to the present invention, the area of the entire flat fluorescent lamp can be reduced relative to the effective light emitting area, so it is possible to reduce the size and weight, and the mechanical strength of the reinforced glass is reduced. It has excellent optical strength and has uniform brightness over the entire surface of the fluorescent lamp, making it suitable for backlighting LCD TVs.

[Brief explanation of drawings]

Figures 1A, 1B, and 1C are a plan view, an A-A' sectional view, and a B--
B' sectional view Figure 2 is an exploded perspective view of the discharge electrode, Figure 3 A and B are front and side views showing other embodiments of the reinforcing glass, and Figure 4 A and B are the second embodiment of the reinforcing glass of the present invention. Plan view and A-A' sectional view showing the embodiment, Figure 5A,
B is a plan view showing the third embodiment of the present invention, and A-
A′ sectional view, FIG. 6 is a perspective view of the lower flat glass, FIG. 7 is a perspective view showing another embodiment of the lower flat glass,
8A, 8B, and 8C are plan views showing the fourth embodiment of the present invention, A-A' cross-sectional views, B-B' cross-sectional views, and FIG.
The figure is a side sectional view of a conventional flat fluorescent lamp. 1, 2... Upper and lower flat glass, 3... Frame glass,
4, 4...discharge electrode, 6,7...first and second lead pieces, 10...chip tube.

Claims (1)

[Claims] 1 Consisting of a pair of flat glasses, a frame glass placed between the flat glasses, and an exhaust pipe placed in a part of the frame glass, the pair of flat glasses are arranged inside in opposite directions. A pair of discharge electrodes facing each other in orthogonal directions, and a reinforcing glass arranged substantially parallel to a line connecting the pair of discharge electrodes and having a height substantially the same as the distance between the pair of flat glasses. In the flat type fluorescent lamp, the pair of discharge electrodes is composed of a rear wall, a pair of side walls, an upper wall, and a lower wall, each of which has a U-shape in cross section and vertical cross section,
A flat fluorescent lamp characterized in that a pair of auxiliary electrodes having a U-shaped cross section are installed between the upper and lower walls of the pair of discharge electrodes, the side walls of which are located on both sides of the reinforcing glass.