TWI553698B - Fluorescent light - Google Patents

Description

Fluorescent light

This invention relates to fluorescent lamps, and more particularly to fluorescent lamps that emit ultraviolet light.

In the manufacturing process of a liquid crystal panel used for a large-sized television or the like, a light source that emits ultraviolet light having a wavelength of 300 nm to 400 nm is required, and one of them is an ultraviolet radiation type fluorescent lamp.

However, in the light-emitting tube of the conventional ultraviolet radiation type fluorescent lamp, so-called hard glass such as soda glass, borosilicate glass, or aluminum-hydrazine hydrochloric acid glass is generally used, but since the hard glass absorbs ultraviolet rays, it is used for ultraviolet rays. Radiant lights are not ideal.

Here, a fluorescent lamp using quartz glass as the arc tube is, for example, those proposed in Patent Documents 1 and 2. Since the ultraviolet light of the quartz glass is excellent in transmission characteristics, light can be efficiently taken out.

However, in the manufacturing process of a fluorescent lamp, it is necessary to raise the fluorescent material in the state in which the glass material which comprises a light-emitting tube is heated up to the vicinity of a softening point. Since the softening point temperature of the quartz glass is at a high temperature around 1600 ° C, there is a problem that the phosphor itself is deteriorated due to its high temperature when the quartz glass is heated to such a high temperature and the phosphor is to be attached.

On the other hand, it is conceivable to heat the arc tube at a temperature at which the phosphor does not deteriorate, for example, by using 900 ° C or lower. However, in this case, the quartz glass is not sufficiently softened, and the phosphor is attached to the quartz glass. Weak, the problem of the phosphor peeling off in the lamp lighting.

Further, even if the quartz glass and the phosphor are well adhered, when the lamp is turned off and the lamp is turned off, when the temperature difference between the outer surface of the lamp and the discharge space is large, the phosphor is peeled off in the same manner. As a result, there is a problem that the amount of radiation is lowered. In particular, in the fluorescent lamp used in the manufacturing process of the liquid crystal panel, in order to suppress the temperature rise of the liquid crystal panel and to perform strong cooling, the temperature difference between the inside and the outside of the lamp is increased, and the problem of the peeling of the phosphor is relatively small. profound.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Publication No. 2008-503046

[Patent Document 2] Japanese Patent Publication No. 2007-534128

The problem to be solved by the invention is to provide a phosphor-reflective fluorescent lamp in which a phosphor layer is formed in an arc tube made of quartz glass, and to provide a structure in which the phosphor layer is strongly adhered to the inner surface of the arc tube and even inside and outside the lamp. A structure in which the difference is large and the phosphor layer is not easily peeled off.

In order to solve the above problems, the fluorescent lamp of the present invention is characterized in that an ultraviolet reflecting layer containing yttrium oxide fine particles as a main component is formed on the inner surface of the arc tube and a region other than the light emitting region, and the inside of the ultraviolet reflecting layer is formed. Further, a glass layer formed of a substance having a softening point lower than that of quartz glass is formed over the entire circumference of the arc tube, and a phosphor layer is formed inside the glass layer, and the ultraviolet reflecting layer has a thickness of 30 to 500 μm.

According to the fluorescent lamp of the present invention, since the glass layer is provided on the inner side of the ultraviolet ray reflection layer and the glass layer having a softening point lower than that of the quartz glass is interposed between the phosphor layer and the phosphor layer, the surface of the particles of the glass layer is raised to soften. The phosphor can be strongly adhered to the glass layer up to the temperature.

Further, the glass layer is softened to be firmly fixed to the surface of the quartz glass.

Then, by setting the thickness of the ultraviolet ray reflection layer containing ruthenium oxide microparticles as a main component to 30 to 500 μm, the ultraviolet ray reflection layer can have a heat retention function, and even if the outside of the lamp is cooled, a temperature difference is formed in the illuminating tube because of luminescence. The phosphor layer on the inner surface of the tube does not have a large temperature change, so the phosphor layer does not peel off.

1 is a cross-sectional view in the axial direction of the present invention, and FIG. 2 is a cross-sectional view taken along line A-A.

In the figure, the fluorescent lamp 1 has an arc tube 2 formed entirely of flat-shaped quartz glass. The size of the arc tube is, for example, 14 mm x 42 mm x 650 mm and a thickness of 2 mm.

On the upper and lower outer surfaces of the arc tube 2, a pair of external electrodes 3, 3 facing each other are disposed.

The ultraviolet reflecting layer 4 is provided on the inner surface of the arc tube 2 except for the light emitting region 2a from which the ultraviolet light is taken out from the arc tube 2. In other words, the ultraviolet reflecting layer 4 is formed except for a portion along the axial direction of the inner surface of the arc tube 2, and the region where the ultraviolet reflecting layer 4 is not formed constitutes the light emitting region 2a.

Then, on the inner side of the ultraviolet ray reflection layer 4, a glass layer 5 which is formed by including the light-emitting region 2a and covering the entire inner surface of the arc tube 2 and having a softening point lower than that of the quartz glass is formed.

Further, a phosphor layer 6 is formed inside the glass layer 5.

The glass having a softening point lower than the softening point (1600 ° C) of the quartz glass constituting the glass layer 5 is, for example, a glass containing borosilicate glass, aluminum silicate glass, or barium strontium silicate glass.

Further, the fluorescent system constituting the phosphor layer 6 is, for example, an endowment of live bismuth borate (Sr-BO:Eu), an anthraquinone-activated magnesium aluminate strontium (La-Mg-Al:Ce (referred to as LAM)), an anthraquinone, an anthraquinone Barium phosphate (La-PO: Gd, Pr) and the like. Any of these fluorescent systems absorbs ultraviolet light in a region having a wavelength of less than 250 nm and converts it into ultraviolet light having a wavelength of 300 to 400 nm.

Then, the ultraviolet ray reflection layer 4 has ruthenium oxide fine particles (SiO ₂ ) as a main component, and the ruthenium oxide fine particles are the same as the material constituting the light-emitting tube 2, so that adhesion (adequate strength) is favored.

Then, the particle size range of the cerium oxide fine particles is, for example, 0.1 to 2 μm, and the center particle diameter (peak of the number average particle diameter) is 0.3 μm.

The particle diameter and the central particle diameter are selected in order to effectively obtain ultraviolet light reflection, and the particle diameter is preferably 0.01 to 10 μm, and the center particle diameter is preferably selected from the range of 0.1 to 3 μm.

Further, the arc tube 2 is used as a light-emitting gas, and for example, a crucible of 53 kPa is sealed.

Then, on the outer surface of the arc tube 2, electrodes 3 and 3 made of a lattice-like metal are provided, and the size thereof is, for example, 32 × 500 mm.

In the fluorescent lamp 1 having the above structure, a lamp for changing the thickness of the ultraviolet reflecting layer 4 was produced, and the presence or absence of peeling of the phosphor layer 6 was examined.

Glass layer: thickness 10μm

Thickness of phosphor layer: 15μm

Explain the experimental method. In a cooling tube (a quartz glass tube having an outer diameter of 85 mm and a thickness of 3 mm) (not shown), the fluorescent lamp 1 is placed such that the light emitting portion 2a faces downward (because it is irradiated downward in the same manner as the actual irradiation device). The air inside the cooling pipe was circulated at 5 m ³ /min to make the lamp air-cooled. The lamp was turned on for 15 minutes and the lamp was turned off for 15 minutes. After the operation was completed for 5 minutes, it was confirmed whether or not there was peeling and the phosphor layer 6 dropped to the light emitting portion. Furthermore, the lamp input is 350W.

The experimental results are shown in Figure 3.

×: peeling of the phosphor layer in the direction of the lamp axis

△: There is no peeling off in practical use.

○: There is no peeling of the phosphor layer at all

According to the results of this experiment, it was confirmed that the peeling of the phosphor layer 6 can be suppressed by setting the thickness of the ultraviolet-ray reflective layer 4 to 30 μm or more.

This effect can be speculated by the following. Since the ultraviolet ray reflection layer 4 is formed as a main component in which cerium oxide fine particles are deposited, a large number of voids exist in the inside. The ultraviolet reflecting layer 4 has heat insulating properties by the heat-insulating action of the voids. In other words, by setting the ultraviolet ray reflection layer 4 to a predetermined thickness or more, even if the cooling lamp is reinforced, the glass layer 5 and the phosphor layer 6 are not cooled by the heat insulating effect, and the high temperature state inside the lamp is not generated. In addition to the temperature difference, the sharp temperature drop at the time of lamp elimination is also suppressed, and the peeling of the glass layer 5 is not caused, so that the phosphor layer 6 is not peeled off.

Further, by increasing the thickness of the ultraviolet reflecting layer 4, the heat insulating effect is enhanced. However, although the ultraviolet ray reflection layer 4 can be formed by using a thickness of several hundred μm, it is preferable that the ultraviolet ray reflection layer 4 itself is formed without being peeled off, and 500 μm or less is preferable. As a result, the thickness of the ultraviolet ray reflection layer 4 is 30 to 500 μm, and it is preferable that the detachment of the phosphor layer is favorably prevented in 60 to 500 μm.

As described above, the fluorescent lamp of the present invention forms an ultraviolet ray reflecting layer containing cerium oxide fine particles as a main component by the inner surface of the arc tube, and the softening point is formed over the entire inner side of the ultraviolet ray reflecting layer. a glass layer made of a substance lower than quartz glass, and a phosphor layer is formed inside the glass layer, and the phosphor layer is strongly adhered to the arc tube, and the thickness of the ultraviolet reflecting layer is set to 30 to 500 μm. Therefore, the ultraviolet reflecting layer has a heat retaining function, and even if the temperature difference between the inside and the outside of the lamp is large, the phosphor layer does not peel off from the arc tube.

1. . . Fluorescent light

2. . . Luminous tube

3. . . electrode

4. . . Ultraviolet reflective layer

5. . . Glass layer

6. . . Phosphor layer

Fig. 1 is a cross-sectional view in the axial direction of a fluorescent lamp of the present invention.

Fig. 2 is a cross-sectional view taken along line A-A of Fig. 1;

Fig. 3 is a view showing a result of a peeling test of a phosphor layer by a thickness of an ultraviolet reflecting layer.

1. . . Fluorescent light

2. . . Luminous tube

2a. . . Light exit area

3. . . electrode

4. . . Ultraviolet reflective layer

5. . . Glass layer

6. . . Phosphor layer

Claims (1)

A fluorescent lamp having an arc tube made of quartz glass and emitting ultraviolet rays, wherein an ultraviolet reflecting layer containing cerium oxide microparticles as a main component is formed on an inner surface of the arc tube and outside a light emitting region. The ultraviolet reflecting layer has a thickness of 30 to 500 μm and has a heat retaining function. On the inner side of the ultraviolet reflecting layer and over the entire circumference of the arc tube, a glass layer formed of a substance having a lower softening point than quartz glass is formed. A phosphor layer is formed on the inner side of the glass layer; the phosphor layer mainly emits ultraviolet rays having a wavelength of 300 nm to 400 nm; and the ultraviolet reflection layer contains cerium oxide particles having a particle diameter of 0.01 to 10 μm and a center particle diameter of 0.1 to 3 μm. .