JPS6112334B2 - - Google Patents

Description

[Detailed Description of the Invention] (1) Field of Application of the Invention The present invention provides a discharge lamp with a discharge vessel consisting of an inner and outer double glass bulb, by optimizing the arrangement of electrodes and the structure of the inner glass tube. The present invention relates to a miniaturized low-pressure discharge lamp with high brightness. A single-cap compact fluorescent discharge lamp is a typical application example of the present invention.

(2) Prior Art Conventional fluorescent discharge lamps for illumination generally have a structure in which electrodes are installed at both ends of a long and thin glass tube, but such long discharge lamps are inconvenient to handle depending on the situation. There was a desire to develop a compact, bright discharge lamp with a short length.

The present inventors previously invented a single-cap compact fluorescent discharge lamp in which the plasma of the discharge lamp is driven by the magnetic field of a permanent magnet, but the present invention provides an alternative to this.

(3) Purpose of the Invention In a discharge lamp with a double inner and outer tube structure, it is difficult to fill the discharge space surrounded by the outer and inner tubes with uniform plasma. Although plasma homogenization has been achieved in discharge lamps equipped with permanent magnets, the present invention aims to develop a discharge lamp having the same performance without using permanent magnets. More specifically, although it is not possible to obtain uniform plasma in the present invention, the present invention aims to realize a discharge lamp that has uniform brightness in appearance.

(4) General description of the invention In a discharge lamp with a double inner and outer tube structure, a cathode is provided in the inner glass tube, and a plurality of anodes are provided outside the inner glass tube in the outer glass bulb, and a discharge current is applied to the plurality of anodes. The present invention relates to a discharge lamp having a structure in which the divided discharge current is stably conducted over the entire length of the discharge lamp. The formation of a discharge path through which a discharge current can be stably conducted was achieved by flattening the inner glass tube and forming a relatively wide partial space in the space surrounded by the outer glass bulb and the inner glass tube.

(5) Examples Hereinafter, the present invention will be explained in detail with reference to examples. Fig. 1 shows an embodiment of the present invention, in which the outer glass bulb 1 has a tube length of 20 cm and a tube diameter of 8 cm at its maximum.
cm, and the inner glass tube 2 has an outer diameter of 3.2 cm and an inner diameter of 3 cm.
The glass tube is heated and flattened, and the major axis is 4.
cm, the short axis is 1.5 cm, and the tube length is 17 cm. The outer glass bulb 1 and the inner glass tube 2 are installed substantially coaxially, and the inner and outer surfaces of the inner glass tube 2 and the inner surface of the outer glass bulb 1 are coated with a phosphor 3. The inner glass tube 2 is adhesively fixed at the stem 4 with an inorganic adhesive. The stem 4 supports a filament cathode 5 coated with an electron-emitting material, and the flare of the stem 4 supports two rod-shaped cathodes 6 and 6'. Furthermore, these two anodes are installed on both sides of the flattened inner tube. The discharge lamp is exhausted by an exhaust pipe 7, and several Torr of rare gas and mercury are sealed inside.

As shown in Figure 2, this discharge lamp consists of a ballast 8, a diode bridge rectifier 9, and a glow lamp 1.
It is lit by a circuit consisting of a current balancer 11 connecting two anodes. A rectified discharge current flows through the discharge lamp, and this current is equally divided into the anodes 6 and 6'. That is, since the anodes 6 and 6' are connected by the current balancer 11 of the transformer, when current flows into only one anode, an induced voltage is applied to the other anode, and the current flows.
The current is divided evenly and a stable state is maintained.

In addition, the inner glass tube 2 has a flat cross section and has a wide discharge space corresponding to the anodes 6 and 6' as shown in the figure, and a discharge current flows in this space to form discharge plasma as shown by hatching. . As shown in the figure, the entire space of the discharge lamp is not filled with uniform plasma, but on the other hand, the path through which the discharge current flows is fixed and extremely stable, and the ultraviolet rays emitted from the plasma are absorbed by the phosphor on the tube wall. 3, and a considerable amount of the visible light is reflected, so it was confirmed that the discharge lamp has almost uniform brightness over its entire surface.

It is known that among straight-tube high-output fluorescent discharge lamps, discharge lamps with non-circular cross sections have high efficiency. The discharge lamp of the present invention is also a small discharge lamp with a double structure inside and outside, and therefore the temperature of the discharge lamp is high.
The mercury vapor pressure is also high, making it essentially a high-power fluorescent discharge lamp. The flattened inner glass tube of these discharge lamps increases the conversion efficiency of ultraviolet rays into visible light, contributing to the improvement of the efficiency of the discharge lamp, and since no changes have been made to the external design of the discharge lamp, the lighting It is highly effective as a light source.

In the embodiments shown in FIGS. 1 and 2, the inner glass tube 2 has a substantially flat structure, but the third embodiment
As shown in the figure, it may be an elliptical cross section, or the fourth
It goes without saying that the same effect can be obtained even if the cross section is rectangular as shown in the figure.

(6) Summary As explained above, according to the present invention, in a low-pressure discharge lamp with a double inner and outer tube structure, discharge can be stabilized by dividing the discharge current to a plurality of anodes and flattening the inner glass tube. A compact, single-cap discharge lamp that achieves uniform brightness through reflection from the phosphor has characteristics that allow it to be used for the same purposes as incandescent light bulbs. In addition, considering the high efficiency of fluorescent lamps and the high efficiency of non-circular cross sections, it has great practical effects as an energy-saving light source.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an embodiment of the present invention having multiple anodes with a double inner and outer tube structure and an inner glass tube with a flat cross section. Fig. 2 shows a circuit for lighting the discharge lamp of Fig. The state drawings, FIGS. 3 and 4, show cross-sectional views of other embodiments of the present invention. 1...Outer glass bulb, 2...Inner glass tube, 3
...fluorescent material, 4. stem, 5. filament cathode,
6,6′...Anode.

Claims (1)

[Claims] 1 a sealed outer glass bulb; at least a rare gas sealed within the outer glass bulb;
an inner glass tube disposed substantially coaxially within the outer glass bulb, one end of which is open and the other end closed; a cathode of
a plurality of anodes provided outside the inner glass tube and on the closed end side of the inner glass tube within the outer glass bulb, and between each of the plurality of anodes and the single anode. A low-pressure discharge lamp characterized in that the inner glass tube has a flat cross-sectional shape in order to form a DC discharge path in which the current is divided into two.