JPH0322020B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a rare gas discharge lamp, and more specifically, in a rare gas lamp that uses light emission from a rare gas, a getter is used to prevent impurity gas from adversely affecting light emission, starting, and life. Regarding the built-in getter, it concerns the installation method and composition of the getter. A rare gas discharge lamp is a fluorescent lamp in which a lamp equipped with an electrode, especially a preheated electrode, is filled with a rare gas such as neon or arun and started at a low voltage, similar to a fluorescent lamp, and uses the luminescence of the rare gas atoms. Compared to lamps, they have less deterioration and less change in temperature characteristics, making them suitable for industrial lamps such as facsimile and OCR. However, if impure gas is mixed in, it becomes difficult to start, or if the impure gas contains atoms or molecules with an excitation voltage lower than the excitation voltage of rare gas atoms, the energy injected into the lamp will be reduced. First, it is consumed by molecules or atoms with a low excitation voltage, producing unnecessary light emission, making it impossible to obtain a rare gas discharge lamp with good color purity, and also having the drawback that efficiency is reduced. For example, 640mm of Ne rare gas discharge lamp
Red light emission requires an energy of about 19 eV, but as an impure gas N ₂ (resonant excitation voltage N ₂ :
6.1ev, N: 10.2ev), O ₂ (O: 9.1ev), H ₂
(12.2ev), etc., the energy of about 13ev is sufficient for the emission of impure gas, so the impure gas and the target emission of Ne gas are mixed, resulting in good purity and efficiency. A good Ne red-emitting lamp cannot be obtained. In addition, the generation of impure gas due to wear and tear of the cathode material during lighting makes the discharge unstable.
It has the disadvantage of shortening its lifespan. This invention was made in view of the above circumstances, and each electrode in the lamp is provided with a predetermined getter metal so as not to impede the operation of the electrode, ensuring lighting with a low starting voltage, long life, and high purity. The purpose is to produce good noble gas luminescence. Next, the details of this invention will be explained using the drawings. FIG. 1 is a broken cross-sectional view of the vicinity of the electrode portion of a rare gas discharge lamp showing one embodiment of the present invention. A rare gas discharge lamp 1 is formed by melt-sealing a stem 3 at the end of a glass bulb 2 to form a discharge vessel. The inner surface of the glass bulb 2 is not coated with anything. Two electrode support wires 4 are sealed to the stem 3, and a preheated electrode 5 is installed at the tip of the electrode support wires 4. A getter holding line 6 is connected to the electrode support line 4, and second, third, and
A getter structure 7 made of one or more metals from Groups 4 and 5 is held in the vicinity of the preheated electrode 5. When a Ba or Mg flash getter is used as the getter, the getter emitting surface of the getter structure 7 should be oriented in the opposite direction to the electrode, and the getter should be installed so as not to affect the electrode. desirable. This getter structure 7 is similarly provided near the preheating type electrode installed at the other end of the lamp. As described above, it is important to always attach a getter to the preheated electrode near each electrode. The electrode support wire 4 passes through the stem 3 and connects to the base 8.
has reached pin 9 of the base. When manufacturing a lamp with the above structure, as a getter, non-evaporable Ti, Zr, Th, Ta, etc.
When using Groups 4 and 5 metals or their alloys, it is important to sufficiently heat them to degas and activate them when exhausting the lamp. In addition, when using a flash getter, after the lamp with the above structure is filled with a rare gas, the flash getter release structure 7 is heated by high frequency induction heating to flash the Ba metal, which is the main component of the getter, and create a glass. The getter 10 is released from the end pipe wall of the bulb 2 to the end of the stem 3 to provide a getter effect. This invention takes into consideration the number, composition, and amount of getters to be installed, and enables rare gas discharge lamps to be reliably lit at a low voltage similar to fluorescent lamps without adversely affecting their lifespan. This is particularly effective when using a preheated electrode. When a lamp has a plurality of preheating electrodes, simply placing one getter near the preheating electrodes to adsorb impurity gas in the lamp does not provide a sufficient effect. Impure gas is generated from the preheated electrode, which wears out as the lamp is turned on, and if this gas is near the electrode, it will inhibit the electrode's electron emission ability, significantly shortening its life, and will cause a transition from glow discharge to arc discharge at startup. There may be cases where this is not the case. Therefore, it is necessary to quickly remove the generated impure gas components. This invention solves this problem by installing a getter in the vicinity of all preheated electrodes installed in the lamp, the amount of which is at least 1/20 times the amount of cathode material deposited, which is thermionic emitting material. It's a method. If the amount of getter is less than 1/20 times the amount of cathode material deposited, it is effective for short-time lighting, but stable discharge cannot be guaranteed for a long time when the cathode material is consumed and the end of its life. There wasn't. Numerous tests have revealed that the amount of getter is required to be at least 1/20 times the amount of cathode material deposited. In the example shown in Figure 1, a lamp with a tube diameter of 25 mm and a length of 436 mm, which has the same dimensions as the fluorescent lamp FL15, was filled with Ne gas.
A rare gas lamp sealed with 4 torr was manufactured. We manufactured lamps with getters attached and ones without getters near the electrodes at both ends. The getter release structure used has a structure in which Ba-Al alloy (Ba ratio 55%) is embedded in a groove on a donut-shaped nickel-clad iron plate substrate. It was flashed and applied to other places. Further, the amount of getter was varied depending on the amount of cathode material deposited on the electrode. When we investigated the characteristics of the completed lamp, we found that the lamp without the getter required a high voltage of 150V to light up, and the luminescence was poor in purity as it contained a spectrum other than the red spectrum of Ne. The lamp with the getter installed was lit at a low voltage (100V) like the general fluorescent lamp LL15, and emitted red light with good Ne purity, but the life characteristics depended on whether the getter was installed on one or both sides of the electrode. Table 1
As shown in the figure, there has been a major change. Note that the amount of getter in Table 1 is indicated by how many times the amount of each getter is the amount of cathode material deposited on each installed electrode.

[Table] The lifespan of those without a getter and those with only one electrode even if a getter was installed were extremely short. The lifespan was extended when getters were installed near the electrodes on both sides, but after a long period of time (2000
In order to guarantee a lifespan of more than 1 hour), many test results show that the amount of getter should be reduced to 1/1 of the amount of cathode material deposited on the electrode.
It was found that it was necessary to increase the number by 20 times or more. 1/20
If it is less than twice as high, the getter ability will be saturated by impure gases such as oxygen that are gradually generated due to consumption of the cathode material during lamp operation, reducing the electron emitting ability of the electrode and causing electrons to be deposited on the electrode during startup or re-ignition. A bright spot that discharges the light will no longer be formed, and a DC component will enter the lighting, leading to the end of its life. As another example, as shown in Fig. 2, a 15 Watt fluorescent lamp (FL15) is constructed by coating a zirconium-aluminum (Zr-Al) alloy getter on a nickel-plated iron plate that is the getter holder 11 near the electrode.
A rare gas lamp filled with 3 torr of Ar gas with the same dimensions as was manufactured. This lamp is a near-infrared emitting lamp that emits a line spectrum in the 700-900 nm region.
Lamps without a getter had a high starting voltage and an extremely short lamp life, making them impractical. A lamp equipped with a getter has a low starting voltage and lights stably.In particular, the getter is installed on both electrodes, and the amount of getter is 1/1 of the amount of cathode material deposited on the electrode.
Those that were 20 times or more had stable discharge over a long period of time and had a long life. Further, the getter composition of the above example was changed to 3rd, 4th,
Belonging to group 5, such as Mg, Ti, Ta, Th, V,
It was confirmed that almost the same effect could be obtained using Ta. In the above example, Ne and Ar are used as the enclosed rare gas.
Although this example shows a rare gas lamp filled with
It goes without saying that He, Kr, and Xe may be used alone or in combination in a rare gas lamp. Furthermore, the effect is not limited to preheating type electrodes, but also rare gas lamps having hot cathode type electrodes. As explained above, in this invention, the amount of getter installed on each electrode structure is 1/20 times or more of the amount of cathode material deposited, which is a thermionic emitting material, so that the cathode material is consumed and its life is reached. It guarantees stable discharge for a long time and has a lifespan of over 2,000 hours.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are broken sectional views of the vicinity of the electrode portion of a rare gas discharge lamp showing different embodiments of the present invention. In the figure, 1 is a rare gas discharge lamp, 2 is a glass bulb, 3 is a stem, 4 is an electrode support wire, 5 is a preheated electrode, 6 is a getter holding line, 7 is a getter discharge structure, 8 is a cap, and 9 is a cap. The pin, 10 is a getter to be adhered to, and 11 is a getter holder. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1 A light-transmitting bulb, a plurality of electrode assemblies in which an electron radioactive material is deposited, and a rare gas are airtightly provided, and a portion of each of the plurality of electrode assemblies excluding the part to which the electron radioactive material is deposited. 2nd, 3rd, 4th, 5th
In a rare gas discharge lamp, the rare gas discharge lamp is provided with a metal mainly composed of one or more metals having a getter action of the above-mentioned group, and at least one of the electrode structures is a preheated thermionic emission type electrode structure. A rare gas discharge lamp characterized in that the amount of getter installed on the lamp is at least 1/20 times the amount of cathode material deposited, which is a thermionic emitting material.