Flat luminescence lamp

Details Flat luminescence lamp Flat luminescence lamp

2001-08-02

2004-06-01

Patel, Nimeshkumar D. (Department: 2879)

Electric lamp and discharge devices

With luminescent solid or liquid material

With gaseous discharge medium

C313S582000, C313S583000, C313S494000, C313S483000, C445S024000

Reexamination Certificate

active

06744195

ABSTRACT:

This application claims the benefit of Korean Application No. 10-2000-80210 filed on Dec. 22, 2000, which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a flat panel display device, and more particularly, to a flat luminescence lamp and method for manufacturing the same. Although the present invention is suitable for a wide scope of applications, it is particularly suitable for reducing size of the lamp, thereby enhancing luminescence.
2. Discussion of the Related Art
An ultra thin flat panel display device has a display screen with a thickness of several centimeters. Especially, liquid crystal display (LCD) devices among the flat panel display device are widely used for monitors of notebook computers, spacecrafts, and aircrafts.
Of such LCDs, a passive luminescence LCD device has a backlight attached at the rear side of a liquid crystal panel and used as a light source. However, the backlight is generally inefficient in terms of weight, power consumption, and thickness.
The backlight used as a light source of an LCD is formed in such a manner that a cylindrical fluorescent lamp is arranged thereon. The backlight includes a direct type and a light-guiding plate type.
In the direct type backlight, a fluorescent lamp is mounted on a flat panel. Since a shape of the fluorescent lamp is displayed on a liquid crystal panel, it is necessary to maintain a certain distance between the fluorescent lamp and the liquid crystal panel and arrange a light-scattering means for a uniform light distribution. In this case, there is a limitation in forming a thin sized backlight.
Due to a trend of a large sized panel, a light-emitting area of the backlight increases. If the direct type backlight has a large area, the light-scattering means should have a sufficient thickness to make the light-emitting area flat. In this case, there is also a limitation in forming a thin sized backlight.
In the light-guiding plate type, a fluorescent lamp is mounted outside the flat panel so that light is dispersed in all sides using a light-guiding plate. In this case, since the fluorescent lamp is mounted at the side and light should pass through the light-guiding plate, a problem arises in that luminance is low. Also, for a uniform distribution of luminous intensity, an advanced optical design and processing technologies are required.
Currently, for high luminance, a direct type backlight has been proposed in which a number of lamps are arranged below the display surface or a lamp is arranged in a bent shape. Further, a flat luminescent backlight having a flat surface facing into the display surface of the panel, thereby illuminating from the entire surface has been researched and developed. This type of the flat luminescent backlight is disclosed in the U.S. Pat. No. 6,034,470.
A related art flat luminescent lamp will be described with reference to the accompanying drawings.
FIG. 1
is a plane view illustrating a related art flat luminescent lamp, and
FIG. 2
is a cross-sectional view taken along the line II—II of FIG.
1
.
As shown in
FIG. 1
, the related art flat luminescent lamp includes a lower substrate
11
, an upper substrate
11
a
, cathodes
13
formed on the lower substrate
11
, anodes
13
a
formed on the upper substrate
11
a
, four frames
19
a
,
19
b
,
19
c
, and
19
d
for sealing the lower and upper substrates
11
a
and
11
by a soldering such as a glass solder, and a plurality of support rods
21
formed between the lower and upper substrates
11
and
11
a.
More specifically, the anodes
13
a
are formed in pairs at constant intervals. The cathodes
13
are formed on the corresponding lower substrate
11
between the anodes
13
a
. The cathodes
13
and the anodes
13
a
are coated with a dielectric material, and an external voltage is applied to the cathodes
13
and the anodes
13
a
through a lead line.
Surfaces of the upper and lower substrates
11
a
and
11
facing into a discharge space are coated with a fluorescent material. In the discharge space, a Xe gas inducing discharge forms plasma and emits ultraviolet rays (UV). The emitted UV comes into collision with the fluorescent material on the upper and lower substrates
11
a
and
11
. For this reason, the UV is excited to generate visible rays.
Additionally, a reflecting plate
14
(shown in
FIG. 2
) is further provided over the lower substrate
11
. The reflecting plate
14
serves to prevent the visible rays generated in the discharge space from leaking out to the rear side of the lower substrate
11
. The support rods
21
are made of a glass material so as not to interrupt emission of the visible rays.
Referring to
FIG. 2
, the cathodes
13
are formed on the lower substrate
11
of a glass material. A first dielectric material layer
12
is formed on the lower substrate
11
including the cathodes
13
. The reflecting plate
14
is formed on the first dielectric material layer
12
and a first phosphor layer
15
is formed on the reflecting plate
14
. The anodes
13
a
that induce discharge together with the cathodes
13
are formed on the upper substrate
11
a
of a glass material.
A second dielectric material layer
12
a
is formed on the upper substrate
11
a
including the anodes
13
a
. A second phosphor layer
15
a
is formed on the second dielectric material layer
12
a
. On the upper and lower substrates
11
a
and
11
, frames
19
a
,
19
b
,
19
c
, and
19
d
are formed thereon to seal the upper and lower substrates
11
a
and
11
by a glass solder. It is well known that the cathodes
13
and the anodes
13
a
are formed by silk printing or a vapor deposition process.
In the aforementioned related art flat luminescent lamp, if a voltage is applied to the cathodes
13
and the anodes
13
a
through a lead line, a Xe gas forms plasma in the discharge space between the cathodes
13
and the anodes
13
a
, thereby emitting UV. In this process, the UV comes into collision with the first and second phosphor layers
15
and
15
a
to generate visible rays, so that the UV is emitted.
However, the related art flat luminescent lamp has several problems as follows.
Since the cathodes and the anodes are formed by silk printing or a vapor deposition process, there is a limitation in reducing the widths of the cathodes and the anodes at 0.2 mm (a minimum value) or below. Accordingly, luminous uniformity of the light-emitting area is deteriorated due to obscure rays near the cathodes and the anodes and discontinuity in plasma.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a flat luminescence lamp and method for manufacturing the same that substantially obviates one or more of problems due to limitations and disadvantages of the related art.
Another object of the present invention is to provide a flat luminescence lamp and method for manufacturing the same in which a problem related to obscure rays is solved by minimizing a width of electrodes of the flat luminescence lamp.
A further object of the present invention is to provide a flat luminescent lamp and method for manufacturing the same in which luminous uniformity is improved by minimizing the number of diffusion sheets, thereby minimizing a thickness and a weight of the lamp.
Additional features and advantages of the invention will be set forth in the description, which follows and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a flat luminescent lamp includes first and second substrates each having a plurality of grooves in sides which the first and second substrates face into each other, first and second electrodes positioned in the grooves, first and second phosphor layers on the

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