JP3203804B2 - Capillary fluorescent lamp and backlight device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tubular fluorescent lamp used in OA equipment and display equipment such as personal computers and word processors, and a backlight device equipped with this lamp.

[0002]

2. Description of the Related Art A conventional thinned fluorescent lamp used for a backlight device such as a liquid crystal display device (hereinafter abbreviated as LCD) has a small input and a tube wall load of 700 to 700.degree. About 800 × 10 ⁻⁶ W / mm ² ,
At this time, the amount of enclosed mercury was about 160 to 180 mg / (W / mm ² ) per 100 mm ³ of discharge space volume, and there was no problem in both the predetermined luminance and the life.

In recent years, as LCDs have become more colorized, the brightness required for lamps has increased, and the input power has also increased, and the wall load has increased to about 1300-1500 × 10 ⁻⁶ W / mm ^2. In a situation where it is difficult to obtain a lamp that satisfies the required life, it has been newly found that the luminescent color deviates from the specification, especially with the elapse of the life.

[0004]

In view of these problems, the present inventors have made various trials and as a result, have paid attention to the amount of mercury sealed in the valve tube. It was found that there was a problem with the amount of mercury because the emission color of the lamp was close to the color tone of the sealed gas over the life of the lamp.

The mercury sealed in the tube generates a mercury compound by an impurity gas in the bulb tube during operation of the lamp, penetrates into a phosphor layer applied to the inner surface of the bulb tube, and forms amalgam with metal in the bulb tube. It has been found that mercury deficiency occurs within the rated life time due to exhaustion due to heat. It has not been recognized that such a problem occurs due to a shortage of mercury.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a long-life fluorescent lamp capable of obtaining a predetermined luminance during a predetermined life even when a high tube load is applied, and a backlight device equipped with the lamp.

[0007]

According to the present invention, a glass tube bulb having a discharge electrode has an inner diameter of 2 mm or less and a tube wall load of 90 mm.
In a tube-type fluorescent lamp of 0 × 10 ⁻⁶ W / mm ² or more, mercury is introduced into the bulb at a discharge space volume of 100 mm ³ per 2 mm 2.
A thin tube-type fluorescent lamp characterized by being encapsulated in an amount of at least 00 mg / (W / mm ² ), and a backlight device using the thin tube-type fluorescent lamp as a light source.

[0008]

Since the mercury sealed in the bulb tube exists for a predetermined life of the lamp, predetermined light characteristics can be obtained during the life.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a cold-cathode discharge lamp used for an LCD backlight or the like. This lamp is a straight tube type having an outer diameter of about 3.5 mm, an inner diameter of about 2 mm, and a total length of about 150 mm. The electrode rods 3, 3 each having a cold cathode 2 made of an iron plate plated with nickel are sealed.

On the inner wall surface of the bulb 1, a coating layer 4 made of alumina and a three-wavelength phosphor layer 5 in which phosphors having emission regions of blue, green, and red are mixed are formed. The valve 1 is filled with mercury at about 60 Torr of a mixed rare gas of argon and neon.

The power of the discharge lamp is 1.
6W, tube wall load between electrodes 2 and 2 is about 1600 × 1
0 ⁻⁶ W / mm ² . In addition, the discharge space volume is electrode 2,
Defined by the volume between the two, this value is about 500 mm ³ .

Then, 500 mg to 1250 mg of mercury is put into the glass tube bulb 1 per 1 W / mm ^{2 of} tube wall load.
The lamp was manufactured by enclosing it in various amounts. The amount of mercury is equivalent to the discharge space volume 100 ³ per 100 to 200 mg.

In the life test of this cold cathode discharge lamp, the lamp is housed in a backlight device (not shown) comprising a reflector and a light diffusion plate, and the cold cathodes 2 Frequency 30KHZ, 100
This was performed by supplying a high-frequency power of 0 V (effective value). In this lamp, the vaporized mercury atoms enclosed in the bulb 1 are ionized and excited, so that the mercury emits ultraviolet rays, which are converted into visible light by the phosphor layer 5 and emitted to the outside of the bulb 1. You.

The rated life of this lamp (usually, the rated life of this lamp is defined as the time when the luminous flux and luminance at 0 hours of lighting are 100%, and the luminous flux and luminance at 50% after the lapse of lighting) are 10,000. Although it is time, as shown in FIG. 2, the life depends on the amount of mercury sealed.

FIG. 2 shows the mercury amount per 100 mm ³ of discharge space volume / (tube wall load) (mg / (W / mm ² )) on the vertical axis.
The horizontal axis represents the lighting life (hours), and if the life is 10,000 hours or more as described above, as is clear from FIG. 200 mg / (W / mm ² ) per 100 mm ^{3 of} volume
It turns out that the above is necessary.

The same test was carried out by trial production of lamps having other powers different from the above-mentioned lamps, ratings, glass tube dimensions and phosphors, and the same test was carried out, but similar results were obtained.

Further, since the application of the present invention simply wastes mercury in a lamp having a low tube wall load, 900 × 10 ⁻⁶ W of a glass tube bulb having a tube inner diameter of 2 mm or less and a high tube wall load is high, such as for a color LCD. / Mm ² or more has a remarkable effect.

The present invention is not limited to the above embodiment. For example, the lamp is not limited to a cold cathode fluorescent lamp, and can be applied to a hot cathode fluorescent lamp.

The sectional shape of the valve may be circular, elliptical, oval, or the like.
It may be bent into a letter shape, a ring shape, or the like.

Further, it is needless to say that the lamp of the present invention can be used not only for a backlight of a liquid crystal display device but also for display and illumination of another display device.

[0021]

As described above in detail, according to the present invention, a fluorescent lamp having a life of 10,000 hours or more can be obtained without deteriorating various characteristics.
The visibility of the display device D and the display device can be improved, and there is no need to replace the display device for a long time.

[Brief description of the drawings]

FIG. 1 is a sectional front view showing an embodiment of a cold cathode fluorescent lamp of the present invention.

FIG. 2 is a graph showing the relationship between the amount of enclosed mercury and the lighting time.

[Description of Signs] 1: Glass tube bulb 2: Discharge electrode (cold cathode) 5: Phosphor layer L: Distance between electrodes

Claims (4)

(57) [Claims] 1. A glass tube bulb having a discharge electrode having an inner diameter of 2 mm or less and a tube wall load of 900 × 10 ⁻⁶ W / mm ^2.
In the above-mentioned thin tube fluorescent lamp, mercury in the bulb is 200 mg / ( W / m / 100 mm ³ of discharge space volume).
m ² ) A tubular fluorescent lamp characterized by being sealed therein. 2. The thin tube fluorescent lamp according to claim 1, wherein the discharge electrode is a cold cathode. 3. The thin-tube fluorescent lamp according to claim 1, wherein said discharge electrode is a hot cathode. 4. A backlight device using the thin tube fluorescent lamp according to claim 1 as a light source.