JPS6316540A - Low pressure mercury vapor discharge lamp - Google Patents

Abstract

PURPOSE:To solve a problem on luminous radiation of ununiformed luminance due to a cataphoresis phenomenon as well as to make light distribution securable in a uniform manner, by making nickel powder so as to be arranged at the anode side of a low pressure mercury vapor discharge lamp to be lighted by a power source having a DC or DC component. CONSTITUTION:This lamp is lighted by a power source installing a node 2 in one end and a cathode 3 in the other end of a discharge passage to be formed by a glass bulb 1, while arranging nickel powder 7 at the side of the anode 2, and having a DC or DC component. And, the nickel powder 7 arranged at the side of the anode 2 is fixed to an inner surface of the inside of the cylindrical anode 2. The cathode 3 installed in the other end is an electrode of an ordinary discharge lamp whose tungsten filament is coated with a corpuscular radiation. In suchlike constitution, for example, if this discharge lamp is lighted by the power source having such a DC component as an alternating current large in a direct current or a pulsating current and a plus component, such a cataphoresis phenomenon that the anode side comes dark will not occur. With this constitution, luminance distribution over the whole range is good enough and, what is more, lighting after voltage being impressed comes very speedy.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention provides a low-pressure mercury vapor that prevents the occurrence of brightness deviations that are thought to be caused by cataphoresis even when lit with direct current or a current having a direct current component. Concerning improvements in the structure of discharge lamps.

(Prior Art) When a low-pressure mercury vapor discharge lamp, such as a fluorescent lamp, is turned on with a direct current or pulsating current, or an alternating current with a large positive component, that is, a power source having a direct current component, a so-called cataphoresis phenomenon occurs.

The mercury ions migrate to the cathode side, causing a shortage of mercury vapor on the anode side, causing the anode side to become dark, resulting in an uneven brightness distribution of the lamp.

(Problems to be Solved by the Invention) The present invention solves the problem of light emission of non-uniform brightness due to the cataphoresis phenomenon of low-pressure mercury vapor discharge lamps, such as fluorescent lamps, which are lit by the above-mentioned DC or power source having a DC component, and It is an object of the present invention to provide an improved fluorescent lamp having a uniform brightness distribution and therefore a uniform light distribution over its entire length.

[Structure of the invention]

(Means for Solving the Problems) The low-pressure mercury vapor discharge lamp of the present invention is a discharge path formed by a glass bulb of a low-pressure mercury vapor discharge lamp such as a fluorescent lamp that is lit by a direct current or a power source having a direct current component. An anode is provided at one end and a cathode is provided at the other end, and nickel powder is arranged on the inner surface of the anode, for example, a cylindrical anode.

(Function) The low-pressure mercury vapor discharge lamp of the present invention is provided with electrodes at both ends of a discharge path formed by a glass bulb, such as in a fluorescent lamp, and one of the anodes of the electrodes has a cylindrical shape, for example. The inner surface is coated with nickel powder. The cathode at the other end is a conventional fluorescent lamp electrode consisting of a tungsten filament coated with an emissive material.

The low-pressure mercury vapor discharge lamp of the present invention having such a structure, such as a fluorescent lamp, suffers from cataholism, in which the anode side becomes dark even when lit by a power source having a direct current component, such as direct current, pulsating current, or alternating current with a large positive component. No phenomenon occurred, the luminance distribution over the entire lamp area was better, and lighting was extremely quick after the voltage was applied. This suggests that when the lamp is turned off, the mercury sealed in the lamp is adsorbed to, for example, nickel powder on the inner surface of the cylindrical anode, and released when the lamp is turned on, eliminating cataphoresis. Seem. The mechanism by which nickel powder adsorbs mercury is not yet clear, but since the nickel powder deposited on the anode has a large surface area, it is thought that adsorption occurs through van der Waalska interaction between the powder and mercury. .

(Example) Details of the low-pressure mercury vapor discharge lamp of the present invention will be explained based on an example of the illustrated fluorescent lamp. FIG. 1 is a perspective view of a fluorescent lamp according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of a cylindrical anode used in the fluorescent lamp.

FIG. 3 is a partially cutaway front view schematically showing another embodiment.

An anode (2) is sealed to one end of a tubular glass bulb (1), and a cathode (3) is sealed to the other end to form a discharge path. anode(
2) to the lead wire (4), and from the cathode (3) to the lead wire (5).
) and (5) are hermetically conductively derived. The inner surface of the glass bulb (1) is coated with a phosphor coating, and the coil filament (6) of the cathode (3) is coated with a conventional electron-emitting material, which is not clearly shown in the figure.

The anode (2) has a cylindrical shape and has nickel powder (7) deposited on its inner surface. A folded back 8) is provided at the discharge side end of the anode (2). This is the anode,
For example, if the cut end of a metal plate such as nickel or iron is exposed to the discharge side, the electric field will concentrate on the edge of the cut end, so this is to prevent this. It is preferable to perform rounding. The inside of the glass bulb (1) is evacuated and filled with mercury and easily dischargeable gas. An example of a method for depositing nickel powder (7) on the anode (2) will be described.

Nickel powder is mixed with aluminum metal powder, which has a lower melting point than nickel, or alkaline earth metal oxides such as magnesia and calcia as a binder, and an organic solvent is added and kneaded to form a paste.

It is applied to the inner surface of an anode made of nickel or iron plate and fired. This operation fixes the nickel powder within the cylindrical anode. If the above-mentioned binder is added at this time, the binder will fuse and secure the fixation.

The cylindrical anode to which the nickel powder is fixed is attached to the lead wire (4) K as shown in Figure 1, and the glass bulb (1
). FIG. 3 is a schematic front view of another embodiment of the fluorescent lamp of the low-pressure mercury vapor discharge lamp of the present invention. Two separate U-shaped inner tubes (IQ, α9) forming a discharge path are enclosed in an outer tube (9) consisting of a glass bulb, the ends of which are respectively open ends (2) and (l The open end (1) of the U-shaped inner tube αl), (11)
B, (Other end (14) opposite to 13), (1!9
are provided with lead wires (1'J, ■) that support the cylindrical anode αe and the cathode σD, which is a tungsten filament coated with an electron emitting material, respectively, and the glass bulb (9) is easily connected inside. It is filled with discharge gas and mercury, and its lower end is sealed together with the U-shaped inner tube σ0, (11). 9) hermetically through the cap (
21) is electrically conductively connected to a pin (22) shown with a portion cut away.

The cylindrical anode α0 has the same structure as that shown in the second figure.

When a direct current or a voltage having a direct current component is applied to the electrodes of the fluorescent lamp shown in FIG. 3, a discharge occurs between the two electrodes. The discharge is induced by hot electrons emitted from the cathode (171), and according to the electric field, the hot electrons head toward the cylindrical anode, and the excited mercury ions head toward the cathode. It is formed by

Even in fluorescent lamps with such a structure, the above-mentioned cataphoresis phenomenon occurs in which mercury vapor is insufficient on the anode side with the anode of the conventional structure, and the brightness becomes uneven.However, the present invention can eliminate this phenomenon. did it.

An example of a method for manufacturing the cylindrical anode (Le) shown in FIG. 2 will be described.

Nickel powder is mixed with oxides of aluminum metal or alkaline earth metals such as calcium and magnesium, an organic solvent is added, and the mixture is kneaded into a paste. By applying the above paste to the inner surface of a cylindrical anode and firing it at about 700°C to 1,000°C in a vacuum or an inert atmosphere such as nitrogen, a cylindrical anode with nickel powder fixed to the inner surface can be obtained. It will be done. In the cylindrical anode manufactured by this method, the nickel powder does not peel off from the raw metal, and a fluorescent lamp with excellent characteristics can be obtained. According to experiments conducted by the inventor, the mercury vapor pressure inside the bulb of the low-pressure mercury vapor discharge lamp of the present invention is as follows: The mercury vapor pressure decreases only by a very small amount, about 1/2, compared to the vapor pressure. For example, in a discharge lamp containing an amalgam such as indium, the mercury vapor pressure decreases by 1/10 to 1/1000.
Therefore, the effect on the characteristics is small, and the light turns on very quickly after voltage is applied, and when the light is turned off, the mercury is adsorbed to the nickel grains in the cylindrical anode, so even if the light is turned on repeatedly, the light will not turn on. It exhibits good optical properties because there is no cataphoresis phenomenon.

〔Effect of the invention〕

As detailed above, the present invention is characterized in that nickel powder is placed on the anode side of a low-pressure mercury vapor discharge lamp that is lit by a direct current or a power source having a direct current component. This has the effect that the mercury is reliably adsorbed by the mercury vapor on the mercury anode side during the second lighting, and an excellent low-pressure mercury vapor discharge lamp without the cataphoresis phenomenon can be provided.

Note that the anode used in the present invention is not limited to the cylindrical anode of the embodiment, and even if the anode has another shape, the same effect will not occur.

Further, the method of fixing the nickel powder to the anode is not limited to the above example, and other methods may be used, but the above example is considered preferable.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a fluorescent lamp according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of a cylindrical anode used in the fluorescent lamp, and FIG. 3 is a partially cutaway front view of another embodiment. (1)...Tubular glass bulb. (2)...Cylindrical anode, (3)...Cathode. (Force...Nickel powder, (9)...Outer tube.

Claims (2)

[Claims] (1) A discharge path formed by a glass bulb is provided with an anode at one end and a cathode at the other end, and nickel powder is arranged on the anode side, so that the discharge path is lit by direct current or a power source having a direct current component. Characteristic low pressure mercury vapor discharge lamp. (2) The low-pressure mercury vapor discharge lamp according to claim 1, wherein the nickel powder disposed on the anode side is fixed on the inner surface or inside of the cylindrical anode.