JPH02230652A - Manufacturing method of low pressure discharge lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a low-pressure discharge lamp, and particularly to a small-diameter low-pressure discharge lamp such as a fluorescent lamp for a backlight. [Prior art] Regarding hot cathode discharge lamps and cold cathode discharge lamps, please refer to the Lighting Handbook edited by the Illuminating Engineering Society of Japan (1930; May 1930, Ohmsha).
It is described on pages 759 to 760 of . Also,
Hot cathode type fluorescent lamps are described on page 160 of the same document. Regarding the structure of the hot cathode, please refer to the Lighting Handbook edited by the Illuminating Engineering Society (November 1932).
(May, Ohmsha), page 121.

[Problem to be solved by the invention]

In the above-mentioned conventional hot cathode type low pressure discharge lamp, two lead wires connected to both ends of one electrode are required in order to heat the electrode by energizing it, and the structure of the tube end of the discharge tube is The disadvantage was that it was complicated. In particular, when the dimensions of the discharge vessel are small, the above drawbacks are fatal8.
For cold A rod type low pressure discharge lamps, one lead wire is required for each electrode.
However, the drawback was that the cathode drop voltage was high and therefore the efficiency was low. Also, the current is O. In a low-pressure discharge lamp with a so-called self-heating type hot cathode that does not heat the cathode under steady lighting conditions, when the operating discharge gas pressure is 100 Torr or less, an arc spot is stably formed. However, the disadvantages were that the discharge became unstable and the lifespan was short. In addition, so-called high-intensity discharge lamps, such as high-pressure mercury lamps, whose discharge current is 0.5 A or more and whose discharge gas pressure is 1,000 Torr during operation, are 5Ba0.2A #zoδ, 5BaO.2AI2.
zOa・3CaO, BasWOe, BazCaWOe,
This is a self-heating hot cathode that uses electron-emitting materials such as 3Ba0 and 4SezOa, but since the pressure of the discharge gas is high and the discharge current is large, an arc spot is stably formed, and therefore a single heat This makes it possible to use multiple lead wires for the cathode. In low-pressure discharge lamps where the discharge current is 0.1 A or less and the discharge gas pressure is 100 Torr or less, an arc spot cannot be stably formed, so only one lead wire is used for one hot cathode. The method has not been implemented.

An object of the present invention is to provide a low-pressure discharge lamp with a simple tube end structure, stable discharge, long life, and high efficiency.

[Means to solve the problem]

The above object is to produce a composite oxide of at least one selected from BaO and SrO and another heat-resistant oxide, and BaO, SrO.
A hot cathode having a structure in which at least one selected from O or a mixture with at least one selected from Ba and Sr is used as an electron emitting material, and only one end of the electrode coated with the pre-dd electron emitting material is supported. This is achieved by using . The hot cathode referred to here is an electrode with a cathode drop voltage of 60V or less, and specifically, the discharge voltage when two electrodes are installed at an interval of 15 thresholds or more and discharge is performed. It is an electrode whose (effective value) is 60V or less.

[Effect]

A composite oxide of at least one selected from BaO and SrO and another heat-resistant oxide, and at least one selected from IaO and SrO or at least one selected from Ba and Sr. When a thermal 113 electrode using a mixture as an electron emitting material is used, the work function is lower than when only a composite oxide of at least one selected from BaO and SrO and another heat-resistant oxide is used. This reduces the cathode drop voltage, resulting in high efficiency, stable arc spot formation, and stable discharge, resulting in a long life. Further, if the structure is such that only one end of the electrode is supported, there is an advantage that the structure of the tube end becomes m-pure.

The above effect is achieved by using a rare gas as the main component of the discharge gas, and assuming that the K molecular weight of the rare gas is M, the pressure of the rare gas expressed in l'orr is 280/M or more and 2.000/M or less. This can be further achieved by doing so. The BaO, Sr
A composite oxide of at least one selected from O and another heat-resistant oxide is 5BaO.2AQzOs. 5Ba0
・2AQz08・3CaO, B aaWOe, B a
If at least one selected from zc a WOs, 3 B a 0 and 4 SczOs is used, these substances are stable in the air and do not require activation, so there is no need to radio-frequency heat the fft pole, and the lamp The advantage is that manufacturing is simplified.

When the electron emitting substance is produced from a mixture of the composite oxide and at least one selected from barium and strontium alcoholates or at least one selected from barium nitride and strontium nitride, The mixture with at least one selected from barium nitride and at least one selected from strontium nitride becomes an oxide, Ba, or Sr at several hundred degrees. 11 times of formation, there is no need for high-frequency heating of the electrodes, and lamp manufacturing time is reduced.
This has the advantage of being 1. [Example] Figure 1 shows a first example of the present invention. Hot cathodes 1 and 2 are sealed at both ends of a straight discharge tube 4. A side view of the electrode and a partially enlarged sectional view of the coil used in the example of FIG. 1 are shown in FIGS. 2(a) and 2(b), respectively. One end of the coil 20 is attached to an electrode support rod 24. The coil 20 is made by making a primary coil by warmly winding a relatively thin tungsten secondary wire 22 around a relatively thick tungsten primary wire 121, and winding this primary coil as a cable wire with a bit P2 and a winding core diameter MD2. In this structure, a tertiary coil is formed by forming a secondary coil, and winding the secondary coil with a pitch of P3 and a winding core diameter of MD3. The primary wire 21 has the role of passing a discharge current to the support rod 24 and maintaining mechanical strength that allows the coil 20 to withstand support at one end, and the diameter of this primary wire is O in terms of mechanical strength. It is desirable that the length exceeds 0.3 m, and preferably 0.2 m or less in order to quickly raise the temperature of the electrode when starting the discharge. The secondary III 22 is relatively thin and has the role of forming a stable arc spot.
It is effective for the diameter of 2 to be in the range of 0.01m* to 0.03m. That is, the diameter is 0. Below 100 ft, the wire may break due to arc spots. 0.03m
If it exceeds l, the arc spot becomes unstable. As shown in FIG. 2(b), the @son radioactive material 23 is filled in the primary coil, but it is filled in the secondary coil, that is, MD2
You can also fill the part. The electron emitting material 23 is an electrode filled with B a xc a W Os, which is an alcoholate of barium.
(O CzH3)z is immersed in a solution containing alcohol or barium nitride dispersed in thinner, this electrode is sealed in the discharge tube 4, and the entire discharge lamp is heated to approximately 450°C. B a 2 C a W
It is a mixture of oe and BaO or Ba. The hot cathodes], 2 are connected to one lead H5, 6, respectively. Since there is only one lead wire, the structure of the tube end of the discharge tube is simple, and there is an advantage that the structure is easy. The advantage of having a simple structure at the tube end is especially significant when the inner diameter of the discharge tube is 8 mm or less.

As shown in Fig. 1, when the electrodes 1 and 2 are provided coaxially with the tube axis of the discharge tube 4, the distance between the electrodes 1 and 2 and the tube wall of the discharge tube 4 increases, and the blackening of the tube end is prevented. The fact that arranging the discharge tube 4 and the 11141.2 coaxially, which has the advantage of being less likely to cause this, is especially advantageous when the discharge tube 4 has an inner diameter of 8 mm or less, is due to the aforementioned reason for limiting the inner diameter of the discharge tube 4. It is also self-evident.

The leads m5 and m6 are provided coaxially with the tube axis of the discharge tube. Conventionally, the discharge tube was installed at an optically constant location by providing a cap at the end of the discharge tube or fixing a part of the tube wall of the discharge tube, but as in this example, When the lead wires 5 and 6 and the tube axis of the discharge tube 4 are coaxial, there is an advantage that optical positioning can be performed using only the lead wires 5 and 6, that is, the lamp can be fixed using only the lead wires. , At least part of the inner surface of the discharge tube 1 is coated with phosphor 3. If the phosphor coating film 3 is present, when inserting the electrodes 1 and 2, the kl 41, 2 will come into contact with the phosphor film 3, causing the phosphor to fall off and the blackening of the tube end to be more noticeable. A system in which one lead wire is provided for one electrode is particularly advantageous.

Figure 3 shows an electrode according to another embodiment of the present invention, in which a primary coil is made by warmly winding a relatively thin tungsten secondary wire 11 around a relatively thick tungsten primary wire 10, and this primary coil is The wire has a structure in which the winding core diameter D is 2 l and the wire is tightly wound to form a hollow cylindrical secondary coil. In other words, the inner diameter D of the hollow portion is 2I. One end of the primary line J
4 is connected to lead wire 5 or 6. Electron emitting material 23 is filled in the primary coil. Of course, the electron emitting material may also be attached to the outside of the hollow cylindrical secondary coil.

When the inner diameter D of the hollow portion is set to 1+um or more and 5m or less, there is an advantage that the discharge starting voltage becomes extremely low. That is, when {circle around (2)} is less than 11, it becomes difficult for the glow to enter the hollow space and the discharge starting voltage becomes high, and when it exceeds 5 doors, the heat capacity becomes large and the discharge starting voltage becomes high.

In this example, the Yasuko emitter 23 is B a
(O C Ha)z, S r (O CzHs)z,
Or barium nitride, strontium nitride, and 5Ba
A coil is filled with a mixture of 0.2ALzOs.3CaO and 5BaO.
2AQzOs・3CaO and BaO, SrO or B
a, formed by converting it into a mixture with Sr. As mentioned above, if a method is adopted in which Ba, Sr alkoxide, barium nitride, or strontium nitride is used at the electrode to generate Ba, SrO, or Ba, Sr, Ba, Sr alkoxide, or Barium nitride and strontium nitride are B at several degrees F.
aO, SrO. Alternatively, since it becomes Ba or Sr, the generation of electron emitting substances requires only a heat source for heating the tube wall of the lamp.
There is no need for high-frequency heating of the electrodes, and there is an advantage that lamp manufacturing is simplified.

In FIG. 1, the electrode having the structure shown in FIG. 3 is used, and the discharge tube 4 has an inner diameter of 5.7 am. A soda glass tube with a length of 270 mm was used, and the inner surface was coated with rare earth fluorescent materials such as YxOs:Eu, MgAQtnOte:Co, Tb, and phosphor 3.
A mixture of 38 rs(POa)z·Ca(,Qz) was applied. The discharge gas was argon and mercury vapor at 10 Torr.

When the above-mentioned low-pressure discharge lamp of the present invention was lit with a discharge current of 40kHz and 20mA, the glow entered the hollow part of the circular lamp at the time of starting the discharge, showing good starting characteristics. Electrodes 1 and 2 operate stably as hot cathodes with a cathode drop voltage of about 20V, the arc is narrowed by the cylinder, the arc spot is also stable, and a brightness of 12,000 nt can be obtained. An efficiency of approximately 1.5 to 1.6 times was obtained. Also, by simply fixing the nightlight with leads fi5 and fi6, it was possible to maintain the optimal optical position. In this way, the optical position can be secured with a simple support structure, making it ideal for back-cracking for liquid crystals, which strongly requires #-shaping. In the above example, a case was described in which one support wire was used, but even if there are two support wires, the structure of the electrode is such that only one end of the electrode is supported, so the structure of the tube end is much smaller than before. becomes simple.

The above example was an electrode with a structure that supported only one end of the electrode, but it is similar to the above example except that the tube end is not simple even with a conventional structure that supports both ends of the electrode. The effect of this can be obtained.

FIG. 4 shows a cross-sectional view of an electrode according to another embodiment of the present invention. A double coil 31 coated with a thermoelectron emitting substance is inserted inside a metal cylinder 30 made of an iron-nickel alloy, and one end of the double coil 31 is connected and fixed to the metal cylinder at a crushed portion 32. ing. The inner diameter D of the metal cylinder 30 is 2
! III. The distance from the open end of the metal cylinder 3o to the tip of the double coil 11 coated with thermionic emitting material is 2 rods, the wall pressure of the metal cylinder is 0.1 m, and the end closed by crushing the metal cylinder One support wire; 33 is attached to the section.

Since the diameter of the metal wire of the double coil is less than 50 μm, the heat capacity of the double coil part is small. The arc spot is generated not on the metal cylinder but on the double coil 11. Metal cylindrical arc spots do not occur. As the material of the metal cylinder, it is not necessary to use high-melting point metals such as tungsten, tantalum, and molybdenum, which are used in high-intensity discharge lamps, and it is sufficient if the melting point is 1400° C. or higher.

As the material for the electrode core rod, iron-nickel and alloys containing iron and nickel are most suitable from the viewpoint of workability.The thermoelectron emitting material is BaaYzWOe, BaO or a mixture with Sr. When the discharge starts, the glow enters the inside of the cylinder, showing good starting characteristics, and the electrode operates stably as a hot cathode with a cathode drop voltage of 16V, and the cylinder narrows the arc, making the arc spot stable. Benefits arise. FIG. 5 shows an electrode according to another embodiment of the present invention, in which B a zc a W Os is used as an electron emitting substance in the #i pole support gland 40.
It has a structure in which a double tungsten coil 4 coated with a mixture of SrO and SrO or 13a is wound. This electrode has the advantage of being easy to manufacture. [Effects of the Invention] According to the present invention, a low-pressure discharge lamp with stable discharge, long life, and high efficiency can be obtained. In addition, a low-pressure discharge lamp with a simple tube end structure can be obtained, the manufacturing method becomes simple, and the discharge lamp can be easily installed.

[Brief explanation of the drawing]

Figure J is a cross-sectional view of one embodiment of the present invention, Figures 2(a) and (b) are side views of an electrode and an enlarged cross-sectional view of a part of the coil in the embodiment of the present invention, and Figures 3 to 3 are FIG. 5 is a diagram showing a cross-sectional view of an electrode according to an embodiment of the present invention. 1.2... Electrical loss, 30... Metal cylinder, 20.31.
... Coil, 23... Electron emitting material. 1st Σ house 2 concave

Claims (1)

[Claims] 1. A composite oxide of at least a species selected from BaO and SrO and another heat-resistant oxide, and at least one species selected from BaO and SrO or Ba and Sr. 1. A low-pressure discharge lamp characterized in that it has at least a hot cathode using a mixture of at least one selected one as an electron emitting substance, and is filled with a discharge gas. 2. The main component of the discharge gas is a rare gas, and the pressure of the rare gas expressed in Torr is 280/M or more and 2,000/M or less, where M is the atomic weight of the rare gas. A low pressure discharge lamp according to claim 1. 3. The electron emitting material is a composite oxide of at least one selected from BaO and SrO and another heat-resistant oxide, at least one selected from alcoholates of barium and strontium, or barium nitride and strontium nitride. Claims 1 and 2 characterized in that the product is produced from a mixture with at least one selected from
A low-pressure discharge lamp as described in any of the above. 4. The composite oxide of at least one selected from BaO and SrO and another heat-resistant oxide is 5BaO.2Al
_2O_3, 5BaO・2Al_2O_3・3CaO,
Ba_3WO_6, Ba_2CaWO_6, 3BaO・
The low-pressure discharge lamp according to any one of claims 1 to 3, characterized in that the lamp is at least one type selected from 4Sc_2O_3. 5. The low-pressure discharge lamp according to any one of claims 1 to 4, wherein the hot cathode has a structure in which one end is supported.