JPH09283082A - Cold-cathode fluorescent lamp and lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescent lamp having uniform light radiation and uniform luminance and capable of improving light flux by providing a glass bulb, cold-cathode electrodes, and a discharge medium, and forming a phosphor film forming face of the bulb inner face into a specific structure. SOLUTION: This fluorescent lamp is provided with a glass bulb 1, at least a pair of cold-cathode electrodes 4 provided in the bulb 1, and a discharge medium (e.g. argon and mercury) sealed in the bulb 1. An irregular face 5 is formed on the inner face of the bulb 1, and a phosphor film 6 is formed on the irregular face 5. The irregular face 5 is preferably formed by etching, e.g. a hydrofluoric acid solution is injected. The sticking strength of a phosphor film 6 formed on the rough surface of the irregular face 5 is increased, its peeling from the bulb inner face can be prevented, and the reduction of the light flux along with the elapse of the lighting time can be decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold cathode fluorescent lamp having a phosphor film formed on the inner surface of a glass bulb.

[0002]

2. Description of the Related Art The structure of a cold cathode fluorescent lamp is such that a glass bulb having a phosphor film formed on its inner surface is provided with electrodes made of cold cathodes, such as plate-like or rod-like, at the both ends of the bulb. A rare gas such as argon gas and an appropriate amount of mercury are enclosed as a discharge medium for facilitating discharge and causing predetermined light emission.

In this cold cathode fluorescent lamp, an electric current is passed through the electrodes to cause a discharge in the bulb, and ultraviolet rays are generated to excite the phosphor film coated on the inner surface of the bulb. Depending on the kind of the phosphor, it is white. The desired light such as daylight color, blue color, and pink color is emitted from the lamp.

In recent years, this cold cathode fluorescent lamp has also been used as a backlight device for ordinary lighting as well as for office automation equipment such as personal computers, word processors and electronic notebooks, and display equipment such as televisions and measuring instruments. As these OA devices and display devices are being made smaller and have higher performance, the lamps used in these devices are also required to be small and have high output.

[0005]

Therefore, various developments have been made on phosphor materials that influence the light output characteristics of fluorescent lamps, and higher light output characteristics than before have been obtained. There is a situation where it is not possible to deal with this by using only phosphor materials.

In view of the above-mentioned circumstances, the present inventor has arrived at the present invention as a result of investigating to further improve the light output characteristics of the cold cathode fluorescent lamp.

It is an object of the present invention to provide a cold cathode fluorescent lamp and an illuminating device equipped with this lamp, in which the light output characteristics are improved by improving the surface of the glass bulb on which the phosphor film is formed. To do.

[0008]

The cold cathode fluorescent lamp according to claim 1 of the present invention is a glass bulb, at least a pair of cold cathode electrodes provided on the bulb, and a discharge enclosed in the bulb. It is characterized in that it comprises a medium, an uneven surface formed on the inner surface of the bulb, and a phosphor film formed on the uneven surface.

Visible light that has passed through the phosphor film is diffused on the uneven surface and emitted as scattered light to the outside of the bulb, and the light emission is even and the total luminous flux of the lamp can be improved.

Further, since the phosphor film made of fine powder formed on the rough surface forming the uneven surface has a larger contact area than the smooth surface, the adhesion strength is increased and the peeling from the inner surface of the bulb is prevented. it can.

The cold cathode fluorescent lamp according to claim 2 of the present invention is characterized in that the uneven surface is formed by etching the inner surface of the bulb.

The uneven surface on the inner surface of the valve is formed by etching or sandblasting with a strong acid such as hydrofluoric acid.
The same operation as described in claim 1 is achieved.

The cold cathode fluorescent lamp according to claim 3 of the present invention is characterized in that the outer diameter of the glass bulb is 5 mm or less.

When the outer diameter of the bulb is 5 mm or less, the backlight device or the like can be downsized and the liquid crystal display device or the like can be downsized.

An illuminator according to a fourth aspect of the present invention comprises a main body of the illuminator and the cold cathode fluorescent lamp according to any one of the first to third aspects installed in the main body. It is characterized by being.

The cold cathode fluorescent lamp mounted on the main body has the same operation as that described in any one of claims 1 to 3.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a partially cutaway front view showing a straight tube cold cathode fluorescent lamp according to the present invention, and FIG. 2 is an enlarged schematic view showing an end cross section of the lamp of FIG.

In the figure, L is a cold cathode fluorescent lamp, and a sealing member 2, 2 formed at both ends of a straight tubular bulb 1 made of, for example, soda lime glass of this lamp L has a rod-shaped cold cathode at its tip. The lead wires 3 provided with the electrodes 4 and 4 constituting the above are respectively sealed. Further, the inner surface of the bulb 1 is provided with a minute uneven surface 5, and a fluorescent material film 6 is formed on the uneven surface 5 by coating.

A discharge medium consisting of a rare gas such as argon and mercury is enclosed in the bulb 1, and a cap (not shown) is provided in the end sealing portion 2 as required.
Is joined or a lead wire (not shown) is connected to the lead wire 3 that is led out.

The uneven surface 5 and the phosphor film 6 are formed as follows. The concave-convex surface 5 on the inner surface of the bulb 1 is formed by, for example, injecting a strong acid such as a hydrofluoric acid solution to etch the surface portion thereof and then washing with hot water to form irregularities having irregular fine ridges. The phosphor film 6 is, for example, a phosphor suspension (coating) liquid prepared by dispersing PEO (polyethylene oxide) binder dissolved in water, phosphor powder and calcium oxide (CaO) in the form of fine particles in water and mixing the dispersion liquid. Then, the phosphor suspension (coating) liquid is poured from the opening of the bulb 1 which is vertically supported and applied onto the uneven surface 5. Then, after being dried, it is baked in a heating furnace or the like to form the phosphor film 6.

Thus, the uneven surface 5 and the phosphor film 6 are formed.
The valve 1 formed with the
The sealing process, the exhaust of the valve 1 and mercury, a rare gas sealing process, the exhaust pipe sealing process, and the like, if necessary, a base attachment and a power supply line connecting process are completed.

The cold cathode fluorescent lamp 1 having such a structure is
When attached to a socket or holder, turned on and turned on,
The operation of the lighting circuit causes discharge between the electrodes 4 and 4 of the fluorescent lamp L, and the lamp 1 emits light.

In this emission, the visible light transmitted through the phosphor film 6 is diffused on the uneven surface 5 and emitted as scattered light to the outside of the bulb 1, and the light emission is even and the luminance of the outer surface of the lamp L is uniform. Is uniform and the luminous flux can be improved.

Further, the fluorescent substance film 6 made of fine powder formed on the rough surface of the uneven surface 5 has a larger contact area than that of the smooth surface, so that the adhesion strength is increased and the fluorescent film 6 is peeled off from the inner surface of the bulb 1. Can be prevented.

Further, the formation of the uneven surface on the inner surface of the valve is not limited to the strong acid, but may be the etching by sandblast.

FIG. 3 is an explanatory view showing an example of an illuminating device using the straight tube type cold cathode fluorescent lamp L of the present invention. The illuminating device shown in the figure is a backlight device B used in a liquid crystal display device, in which B1 is a main body, B2 is a reflecting mirror, B3 and B3 are sockets, and these sockets B3 and B3.
The cold cathode fluorescent lamp L is mounted on the. Also,
B4 is a lighting device having a ballast provided inside or outside the main body B1, and B5 is a light diffusion plate that covers the opening of the main body B1.

The backlight device B is provided with sockets B3, B3 from a power source (not shown) through a lighting device B4.
If power is supplied to the fluorescent lamp L that is supported and connected to, stable lighting is possible. Then, the fluorescent lamp L emits light with a uniform brightness and obtains a high luminous flux, so that the visibility of the liquid crystal display device can be improved.

The present invention is not limited to the above embodiment. For example, the cold cathode fluorescent lamp is not limited to a straight tube type bulb, but may be a ring shape, a U shape, a W shape, a bent shape in which a plurality of straight tubes are connected, a plate shape, or a ball shape such as a bulb type fluorescent lamp. It can also be applied to a lamp using a clasp type bulb. Further, the cold cathode fluorescent lamp may be a reflection type lamp having a bulb on which a light reflecting film is formed. Further, the cold cathode fluorescent lamp is not limited to the one in which mercury is enclosed in the bulb, but can be applied to a lamp of rare gas emission in which mercury is not enclosed.

Further, the type of the fluorescent substance formed on the uneven surface is not limited, and the solvent of the fluorescent substance film forming suspension is not limited to the water-soluble liquid and may be an organic solvent.

Further, the electrodes are not limited to those provided in the bulb and may be external electrodes, and there may be a pair or more.

Further, the lighting device is not limited to the backlight device but can be applied to general lighting and OA equipment.

[0032]

EXAMPLE As an example of the straight-tube type cold cathode fluorescent lamp shown in FIG. 1, a bulb having a total length of 160 mm, an outer diameter of 2.6 mm, and an inner diameter of 2.0 mm provided with cold cathodes at both ends was used. Cold cathode fluorescent lamp L according to the present invention having an uneven surface
Confirmed that the luminous flux could be improved by about 10% as compared with a conventional lamp having no uneven surface (the configuration other than the uneven surface is the same).

FIG. 4 is a graph comparing the relationship between the lamp current and the total luminous flux of the lamp of the present invention and the conventional lamp.
The cold cathode fluorescent lamp L according to the present invention, which has an uneven surface when turned on by the same current, has a higher luminous flux than a conventional cold cathode fluorescent lamp which does not have an uneven surface because light is diffused and scattered on the inner surface of the glass tube. The value was obtained.

(Measurement was carried out by measuring the luminous flux (Lm) of each of the lamp of the present invention and the conventional lamp by changing the current value of the same lamp.)

[0035]

According to the first and second aspects of the present invention, it is possible to provide a cold cathode fluorescent lamp in which the light emission from the lamp is uniform and the brightness is uniform and the luminous flux is improved.

Further, the phosphor film formed on the rough surface, which is the uneven surface, has increased adhesion strength and can be prevented from being peeled off from the inner surface of the bulb, and the reduction of the luminous flux at the lighting diameter can be reduced.

According to the third aspect of the present invention, the cold cathode fluorescent lamp can be made smaller and more efficient by being applied to a lamp having a bulb with an outer diameter of 5 mm or less.

According to the invention of claim 4, since the cold cathode fluorescent lamp which achieves the effects of claims 1 to 3 is mounted, there is an advantage that it is possible to provide an illuminating device having excellent light emission characteristics.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of a straight tube type cold cathode fluorescent lamp according to the present invention.

FIG. 2 is a schematic view showing an enlarged end cross section of the lamp of FIG.

FIG. 3 is an exploded perspective view showing an embodiment of a lighting device according to the present invention.

FIG. 4 is a graph comparing the relationship between the lamp current and the total luminous flux of the lamp of the present invention and the conventional lamp.

[Explanation of symbols]

 L: cold cathode fluorescent lamp 1: glass bulb 4: cold cathode electrode 5: uneven surface 6: phosphor film D: lighting device

Claims (4)

[Claims] 1. A glass bulb, at least a pair of cold cathode electrodes provided on the bulb, a discharge medium enclosed in the bulb, an uneven surface formed on the inner surface of the bulb, and on the uneven surface. And a phosphor film formed on the cold cathode fluorescent lamp. 2. The cold cathode fluorescent lamp according to claim 1, wherein the uneven surface is formed by etching the inner surface of the bulb. 3. The cold cathode fluorescent lamp according to claim 1, wherein the glass bulb has an outer diameter of 5 mm or less. 4. A lighting device comprising: a lighting device main body; and the cold cathode fluorescent lamp according to claim 1, which is installed in the main body.