JPH06290735A - Low pressure discharge lamp - Google Patents

Abstract

PURPOSE:To provide a low pressure discharge lamp provided with a bead mount which can lower the lamp voltage. CONSTITUTION:Regarding a discharge lamp which has a bulb 1 with 22mm or less inner diameter D and 40W or less lamp electric power and in which a mount 3 is sealed at one end of the bulb 1 wherein the mount 3 is prepared by fixing a lead wire 6 to support an electrode by means of a glass bead 5, a distance between the upper face of the glass bead 5 of the mount 3 and the upper most part on an electrode is set to be smaller than the inner diameter D of the bulb 1. When the glass bulb is made thin, the lamp current is suppressed but electron injection is limited by regulating the lead wire part facing to the reverse discharge route and thus electrode voltage lowering loss is prevented to lower the lamp voltage by lowering electrode lowering voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-pressure discharge lamp such as a compact fluorescent lamp using a bead mount.

[0002]

2. Description of the Related Art A low-pressure discharge lamp, for example, a fluorescent lamp, is constructed such that a filament coil in which a tungsten wire is wound in a double or triple manner at both ends of a glass bulb having a phosphor film formed on the inner surface thereof is provided with an electron emitting substance (emitter). A supported electrode is provided. In addition, a discharge gas such as argon gas for facilitating the discharge and an appropriate amount of mercury are enclosed in this bulb.

These fluorescent lamps and the like use a mount in which a filament coil is connected between two lead wires in order to support the electrode composed of the filament coil.

As this mount, a bead mount having a small number of parts and a simple structure is adopted because a glass bulb such as a compact lamp has been reduced in diameter (outer diameter is 22 mm or less), resource saving and cost reduction are required. It is widely adopted.

For example, in the above bead mount, two internal lead wires to which a filament coil is connected need only be fixed by a glass bead, and the position of this bead is to prevent twisting of the filament coil and lead wires. It is mounted away from the filament coil due to its weight balance or because of the shadows that occur during light emission. Further, this bead is a joint until the mount is sealed to the opening end of the valve, and there is also a bead that is buried in the sealing portion after sealing.

As has been known from the prior art, when the diameter of the glass bulb is reduced, the lamp current is suppressed and the lamp voltage rises, and the difference between the restart voltage and the power supply voltage becomes small. Discharge becomes unstable. The same phenomenon can be seen in a fluorescent lamp using a bead mount.

[0007]

Therefore, as a result of various investigations on these phenomena, the inventors of the present invention have found that the bead blocks the injection of electrons into the internal lead wire during the anode cycle, and the electrons on the anti-discharge side of the bead. I found that he was trying not to go around. For this reason, the bead position is set to the discharge space,
That is, as the distance from the filament coil is increased, electrons are attempted to be injected into the internal lead wires near the sealing portion, and as shown in FIG. 3, the electrode drop voltage is increased to increase the electrode loss, and at the same time, the lamp voltage is increased. We tried to improve these problems. In FIG. 3, the horizontal axis is the distance between the bead and the tip of the internal lead wire (mm), and the vertical axis is the electrode drop voltage (V).
The measurement method is based on “Matsushita Electric Technical Report No. 29 (Aug. 1984) Wada, Toho:“ Indirect measurement method of axial tube voltage of fluorescent lamp ”.

An object of the present invention is to provide a low pressure discharge lamp having a bead mount capable of reducing the lamp voltage.

[0009]

According to a first aspect of the present invention, there is provided a low pressure discharge lamp in which a mount, in which a lead wire supporting an electrode is fixed by a glass bead, is sealed at an end of a bulb, and the glass of the mount is mounted. The feature is that the distance between the upper surface of the bead and the top of the electrode is smaller than the inner diameter of the bulb.

The low pressure discharge lamp according to claim 2 of the present invention has a bulb inner diameter of 22 mm or less and a lamp power of 40 W.
It is characterized by the following.

[0011]

[Function] Although the lamp current is suppressed when the diameter of the glass bulb is reduced, the injection of electrons is restricted by restricting the lead wire portion facing the anti-discharge path, and the electrode drop voltage is reduced to reduce the electrode drop loss. Prevents reduce the lamp voltage.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of one end of a straight tube type fluorescent lamp. In the figure, reference numeral 1 denotes a bulb made of soga glass, lead glass or the like, and a predetermined phosphor film 2 is formed on the inner surface thereof. Further, 3 is a bead mount sealed in the crushing sealing portion 4 at the end of the bulb 1, and a glass bead 5 made of lead glass or the like and two lead wires made of iron, nickel alloy wire, Dumet wire, or the like. An electrode filament 7 formed by burying a double or triple winding of a tungsten wire is connected between the tip portions of the lead wires 6 and 6 while embedding and supporting the intermediate portion of the electrode filaments 7. An emitter is applied to the surface of the. Reference numeral 8 in the drawing denotes an exhaust pipe sealed by the crushing sealing portion 4.

Further, a predetermined amount of mercury and a rare gas such as krypton or xenon having a predetermined pressure are enclosed in the bulb 1.

The dimensions of the above respective parts are as follows: the outer diameter of the valve 1 is about 17.5 mm, the inner diameter (D) is about 15.3 mm, the distance between the lead wires 6 and 6 is about 8.5 mm, and the lead wire 6 projects inside the valve 1. Length of about 18mm, outer diameter of the bead 5 about 2mm,
Lead wire 6 with a length of about 12 mm and located at the highest position in the electrode
The distance (L) between the uppermost end of the bead 5 and the upper surface of the bead 5 is about 8 mm.

The distance between the uppermost end of the lead wire 6 at the highest position in the comparative electrode and the upper surface of the bead 5 is about 16 mm (other parts have the same size as above). When an electrical characteristic test with a conventional lamp was conducted, the results shown in (Table 1) were obtained.

[0016]

[Table 1] As is clear from this (Table 1), in the product of the present invention, the lamp voltage is 5 ° C. at room temperature (25 ° C.) and at low temperature in comparison with the conventional product.
At that time, it became 2V lower. In addition, conventional products during low temperature testing,
The lamp voltage exceeded the re-operation voltage (65 V) of the ignition tube, and re-operation was caused, resulting in a short life.

The inventors of the present invention have conducted various electrical characteristics tests by changing the lamp power, the inner diameter of the bulb 1 and the distance between the uppermost end of the conductor at the highest position in the electrode and the upper surface of the glass bead 5, and the lamp power is shown. In the bulb 1 having an inner diameter of 22 mm or less and 40 W or less, if the distance (L) is smaller than the inner diameter (D) of the valve 1, that is, the bead 5 is closer to the conductor portion of the electrode such as the filament 7, the electrical characteristics can be improved. It was confirmed that the relationship of D ≧ L was sufficient. Further, at this time, when the distance (H) between the lower surface of the electrode filament 7 and the upper surface of the bead 5 is 5 mm or less, electrode drop loss is small, and the length (W) of the bead 5 extends in the sealing portion 4 direction. The longer the distance (S) between the existing lead wires 6, the better the characteristics because the injection of electrons was restricted.

This is because, in a lamp having a small tube diameter and a large distance between the electrode filament and the bead, which is an ineffective discharge length with respect to the effective discharge length between the opposing electrodes, an electron to the lead wire located on the side opposite to the discharge path is formed. It can be judged from the fact that by regulating the injection of H.sub.2, the electrode drop voltage can be lowered, the electrode drop loss can be prevented, and the lamp voltage can be lowered. And, by having such an electrode configuration, the starting characteristics of the lamp,
In particular, even when the applied voltage drops and the lamp voltage rises at a low temperature, a large difference from the restart voltage of the ignition tube can be taken, so that it is possible to provide a discharge lamp with a long life without early consumption of the emitter due to restart. .

2 (a) and 2 (b) show another embodiment of the bead mount 3 of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. In the figure (a), the lead wires 6 and 6 are linear, in the figure (b), the lead wires 6 and 6 below the glass bead 5 are linear, and what kind of mount 3 is used Whether to do it is 1 valve diameter,
Length of electrode filament 7 and glass bead 5, exhaust pipe 8
It may be selected as appropriate depending on the presence or absence of.

The uppermost end of the conductor at the highest position in the electrode in the present invention may be the upper surface of the filament 7 as shown in FIG. 1 or may be projected from the tip of the lead wire 6 or the lead wire 6. It may be the tip of the anode, and the distance (L) from the uppermost end of these conductors to the upper surface of the glass bead 5 is substantially related.

The present invention is not limited to the above embodiment. For example, the lamp is not limited to a fluorescent lamp, but may be another low-pressure discharge lamp such as an ultraviolet radiation lamp, and the electrode filament may be a double or triple coil or a stick coil having a core wire. Further, it may be a low-pressure discharge lamp in which a rare gas such as argon, krypton, xenon, neon, or nitrogen, in which no mercury is enclosed, is enclosed in the bulb.

The shape of the lamp of the present invention is a straight tube shape or a U shape.
It may be a curved tube shape such as a letter shape, a W shape, or a saddle shape. Further, the material of the lead wire and the glass bead is not limited to that of the embodiment, and the lead wire in which the material of each of the inside, the sealing portion, and the outside is changed, the glass bead with a low melting point and a small amount of impure gas, etc. Materials having similar thermal expansion coefficients may be selected in consideration of materials and the like.

Further, the means for forming the sealing portion between the valve and the bead mount is not limited to the crushing sealing using the pincher of the embodiment, but may be other means such as shrinking the glass by heating to seal. Sealing may be performed in which exhaust and sealing are performed simultaneously without using an exhaust pipe.

[0024]

As described in detail above, according to the present invention, by restricting the injection of electrons from the electrode filament forming the discharge starting point to the lead wire located on the non-discharge side,
The electrode drop voltage can be lowered to prevent electrode drop loss, and the lamp voltage can be lowered. With such an electrode configuration, the starting characteristics of the lamp, especially when the applied voltage decreases and the lamp voltage increases at low temperature,
From the fact that the difference with the restart voltage of the lighting tube can be made large,
It is possible to provide a discharge lamp having a long life without early consumption of the emitter due to re-operation.

[Brief description of drawings]

FIG. 1 is a front sectional view showing a sealing part of a discharge lamp of the present invention and a bead mount sealed to the sealing part.

2A and 2B are front views showing another bead mount of the present invention.

FIG. 3 is a graph showing a space (mm) between a bead and a tip of an internal lead wire and an electrode drop voltage (V) for comparison.

[Explanation of symbols]

 1: Valve D: Inner diameter of valve 3: Bead mount 4: Crushing and sealing part 5: Glass bead 6: Lead wire 7: Electrode filament

Front page continuation (72) Inventor Kimio Shiraiwa 1-28-3 Mita, Minato-ku, Tokyo Toshiba Lighting & Technology Co., Ltd. (72) Hidenori Ito 1-4-2-4 Mita, Minato-ku, Tokyo Toshiba Lighting & Technology Co., Ltd. In-house (72) Inventor Takeo Yasuda 1-428 Mita, Minato-ku, Tokyo Inside Toshiba Lighting & Technology Corporation

Claims (2)

[Claims] 1. A low-pressure discharge lamp in which a mount, in which a lead wire supporting an electrode is fixed by a glass bead, is sealed at an end of a bulb, wherein the distance between the upper surface of the glass bead of the mount and the top of the electrode is the bulb. A low-pressure discharge lamp characterized by being smaller than the inner diameter of. 2. The low-pressure discharge lamp according to claim 1, wherein the bulb has an inner diameter of 22 mm or less and a lamp power of 40 W or less.