JP2000285850A - Electric discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric discharge lamp with high quality and high reliability in which dispersion of an electric discharge voltage is reduced by preventing a space dispersion between electrodes and improving an electric insulation means of electrodes. SOLUTION: An electric discharge lamp is provided with a glass tube valve 1; a pair of lead wires 4, 4 sealed to a sealing portion 2 of the valve 1 end portion; electrodes 6, 6 which are provided opposed to a pair of lead wires 4, 4 at a predetermined electric discharge space and of which the tip end portion is engaged; a metal oxide layer 7 covered and formed on a surface portion of at least one side electrode 6; and an electric discharge rare gas filled in a valve 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp such as a neon lamp in which a pair of electrodes are sealed in a relatively small diameter glass tube bulb in parallel.

[0002]

2. Description of the Related Art Neon lamps are well known and frequently used as pilot lamps for use in displaying voltage of electric equipment. This neon lamp is a kind of a discharge lamp in which a low-pressure rare gas is sealed in a glass tube bulb and a pair of electrodes are provided to face each other, and display is performed using a glow discharge generated between the electrodes as a light source. is there.
It is known that the characteristics of this discharge lamp vary depending on conditions such as the distance between a pair of electrodes, the state of the electrode surface, the type of rare gas, and the sealing pressure thereof.

[0003] For example, in the neon lamp used for indicating the energization of a device or the like, a pair of electrodes are arranged close to each other because the outside diameter of a glass tube forming a bulb is reduced to about 6 mm or less. . Therefore, if the distance between the electrodes made of a conductor is small, electric discharge is likely to occur. Therefore, a layer made of a metal oxide such as aluminum oxide is formed on the surface of the electrodes to increase the insulation resistance and increase the discharge starting voltage. Have been done.

However, in a neon lamp or the like that has been miniaturized in this way, a predetermined discharge starting voltage cannot be obtained unless the interval between the electrodes is maintained with high accuracy, and the variation in the interval causes a variation in the discharge starting voltage. And the effect on the characteristics was large.

It has also been found that another cause of the variation in the firing voltage is the metal oxide layer formed on the surface of the electrode. If the center of the discharge occurs near the center of the two electrodes, the variation in the firing voltage is small, and preferably, if the center of the discharge occurs near the end of the electrode, the variation in the firing voltage is large, and In addition, the light emission range was narrow and the light emission characteristics were reduced.

[0006] This is due to the fact that the layer is damaged and peeled off or thinned during the manufacture and handling of the electrode, especially in the vicinity of the tip of the electrode, or the metal oxide layer connected to the electrode. It is considered that the unleaded wire portion is thinner than other portions even if there is no metal oxide layer having an electrical insulating property, so that the work function is lowered. Therefore, it is considered that discharge is easily generated from this portion.

[0007]

DISCLOSURE OF THE INVENTION The inventors of the present invention have studied variously because the variation in the firing voltage is caused by the distance between the electrodes or the conditions for forming an electrically insulating metal oxide layer on the electrodes. And found a solution.

[0008] The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide a high-quality and highly reliable discharge lamp in which the variation in the firing voltage is reduced by preventing the variation in the interval between the electrodes and improving the electrical insulation means of the electrodes.

[0009]

According to a first aspect of the present invention, there is provided a discharge lamp comprising: a glass tube bulb; a pair of lead wires sealed at a sealing portion at an end of the bulb; An electrode provided opposite to the wire at a predetermined discharge interval and having a fixed tip, a metal oxide layer formed on at least one surface of the electrode, and sealed in the bulb. And a discharge rare gas.

Since the pair of electrodes in the bulb are embedded and fixed in glass such as a glass bead, opposed electrode portions are arranged in parallel at a predetermined interval and can be securely held firmly.

The metal oxide layer formed on the surfaces of both electrodes is electrically an insulating layer, and can prevent undesired discharge at low voltage between adjacent electrodes. In particular, the tip of the electrode, where the metal oxide layer is easily peeled or scratched and the insulating property may be reduced, is fixed by being buried in the glass, so that a discharge center may be generated at this tip. Absent.

[0012] The discharge lamp according to claim 2 of the present invention comprises:
A tip of the pair of electrodes is embedded in the bulb.

The distal ends of the pair of electrodes are directly buried and fixed in the glass on the top side of the bulb, and have the same effect as in the first aspect.

[0014] The discharge lamp according to claim 3 of the present invention comprises:
A pair of electrodes is fixed via an insulator.

The distal ends of the pair of electrodes are embedded and fixed in the glass on the top side of the bulb via a glass bead or the like, and have the same effect as in the first aspect.

[0016] The discharge lamp according to claim 4 of the present invention comprises:
A glass tube bulb, a pair of lead wires sealed to a sealing portion at the end of the bulb, an electrode provided opposite to the pair of lead wires at a predetermined discharge interval, and at least one side. It is characterized by comprising a metal oxide layer formed on the surface of the electrode and the lead wire in the bulb, and a rare gas for discharge sealed in the bulb.

The surface of the lead wire portion has a lower insulating property than the surface of the electrode coated with the metal oxide layer, and conversely, the work function is low, so that the discharge easily occurs. The surface of this lead wire portion is also covered with a metal oxide layer having electrical insulation,
This has the effect of preventing the occurrence of discharge from the lead wire portion.

[0018] The discharge lamp according to claim 5 of the present invention comprises:
A glass tube bulb, a pair of lead wires sealed to a sealing portion at the end of the bulb, an electrode provided opposite to the pair of lead wires at a predetermined discharge interval, and at least one side. A metal oxide layer formed on the surface of the electrode, glass covering the surface of the lead wire in the bulb, and a discharge rare gas sealed in the bulb. I do.

By coating the surface of the lead wire portion with a vitreous layer containing a plurality of types of metal oxides, the same effect as described in the fourth aspect can be obtained.

The discharge lamp according to claim 6 of the present invention comprises:
A pair of lead wires is sealed to a sealing portion formed at one end of the glass tube bulb.

The lamp formed in the sealing portion at one end of the bulb has the same function as the above-mentioned first to fifth aspects.

The discharge lamp according to claim 7 of the present invention comprises:
A lead wire is sealed to each of sealing portions formed at both ends of the glass tube bulb.

The lamps formed at the sealing portions at both ends of the bulb have the same functions as those of the above-mentioned first to fifth aspects.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional front view showing a discharge lamp, for example, a one-end sealed neon lamp L1, FIG.
(C) is a schematic front view of the mount.

The neon lamp L1 has a rating of, for example, 3
30VDC-0.1mA, glass wall thickness is about 0.4
mm, outer diameter about 4.2mm, total length about 8mm, inside 11
A pair of lead wires 4 of a mount 3A is sealed to a sealing portion 2 formed at one end of a bulb 1 made of soft glass such as soda lime glass or lead glass having a space length of about 3 mm.

As shown in FIG. 2 (a), the mount 3A is a pair of an electrically insulating glass bead 5A made of the same or similar material as the bulb 1 and a pair of dumet wires having an outer diameter of about 0.4 mm. Lead wires 4 are hermetically sealed at a predetermined interval of about 1.7 mm. The columnar, cylindrical or plate-like discharge electrodes 6 and 6 made of nickel Ni or an alloy thereof are connected to the tips of the lead wires 4 and 4 here.
The electrode 6 has a thickness of about 3 to 4 μm on its surface.
Metal oxide layer 7 made of aluminum oxide Al ₂ O ₃ or titanium oxide TiO ₂ .

The metal oxide layer 7 is formed by immersing the electrodes 6 and 6 in a suspension in which a fine powder of aluminum oxide Al ₂ O ₃ and an organic solvent are mixed and pulling up and drying. Will be

The two electrodes 6, 6 have a predetermined height of about 1.
The bulbs are arranged in parallel at a distance of 0 mm and their tips are buried in the glass at a predetermined distance on the top side 12 of the closed valve 1.

Further, the inside 11 of the valve 1 neon Ne main component to rare gas is several ¹⁰³ to as discharge medium
Several 10 ⁴ Pa (Pascal), for example 133 × 10 ⁴ P
a is enclosed.

The neon lamp L1 is manufactured as follows.
After disposing the mount 3A in the glass tube forming the bulb 1, the top side 12 of the bulb 1 is closed by heating. At the time of this closing, the tips of the electrodes 6, 6 are embedded in the glass at a predetermined interval. At this time, the electrodes 6, 6 do not need to be hermetically sealed to glass.

Next, when the inside 11 of the bulb 1 is evacuated and a rare gas such as neon Ne is sealed therein, the portion where the glass bead 5A, which is the portion to be sealed of the mount 3A, is located is heated to reduce the diameter of the glass tube. The sealing portion 2 is formed by fusing with the glass bead 5A. Thereafter, a base (not shown) is joined to the sealing portion 2 as necessary to complete the lamp L1.

In the neon lamp L1, when a predetermined voltage is applied to the electrodes 6, 6 via the lead wires 4, 4, a discharge occurs between the electrodes 6, 6, and the neon Ni gas is excited. Emits light. Since the discharge start voltage depends on the surface material and interval of the two electrodes 6 and 6 and the type and pressure of the discharge gas, it goes without saying that these conditions are set in advance.

A pair of electrodes 6, 6 in the bulb 1 of the neon lamp L1 are connected at one end to lead wires 4, 4 fixed in a glass bead 5A, and at the other end to the glass 12 on the top side 12 of the bulb 1. Opposing electrodes 6 buried and fixed inside,
Since the six portions are arranged in parallel at a predetermined interval, the discharge interval can be ensured with high accuracy and securely. The aluminum oxide A formed on the surfaces of both electrodes 6
The metal oxide layer 7 made of l ₂ O ₃ or the like is an electrically insulating layer, and prevents undesired discharge at a low voltage between the adjacent electrodes 6. In particular, since the tips of the electrodes 6, 6, which are liable to cause peeling or scratching of the metal oxide layer 7 and degrade the insulation, are buried in the glass, a discharge center may be generated at this tip. There is no.

Therefore, according to the above configuration, the electrodes 6, 6
Since the distance is kept constant and a position separated by 1 mm or more from the insulator (the top 12 of the bulb 1) (discharge is difficult unless the distance from the insulator is 1 mm or more in the discharge space), discharge and emission occur at both electrodes. A neon lamp L1 having a large emission range, an improved emission characteristic, a small emission start voltage, a small emission center, and a large emission range, can be provided.

Such a neon lamp L1 is used, for example, in a voltage display circuit 8 for displaying the charging voltage of the capacitor 81 shown in FIG. In the circuit 8 of FIG. 3, reference numeral 82 denotes a power supply, and a capacitor 81 is connected to the power supply 82.
And a circuit in which the resistor 83 and the lamp L1 are connected in series.

Then, when the capacitor 81 is charged to the predetermined voltage, the neon lamp L1 is turned on to indicate that the charging voltage of the capacitor 81 has reached the predetermined value. When the power is turned off and the voltage drops, the neon lamp L1
Turns off.

In the above embodiment, the mount 3A shown in FIG. 2A is used, but mounts 3B and 3C shown in FIGS. 2B and 2C can be used. FIG. 2 (b)
In the mount 3B, the tips of the pair of electrodes 6, 6 are embedded and fixed at predetermined intervals in a glass bead 5B which is an electrically insulating material. In the sealing step, the lower lead wires 4, 4 are usually inserted and held in a pair of lead wire insertion holes formed in the mount pin at a predetermined interval, and sealing is performed. The electrodes 6, 6 are arranged in parallel at a predetermined interval. The glass bead 5B on the distal end side of the mount 3B may or may not be embedded and fixed in the glass of the bulb 1.

In the mount 3C shown in FIG. 2C, the tips of the pair of electrodes 6, 6 and the lead wires 4, 4 are embedded and fixed in glass beads 5A, 5B. They are arranged in parallel at an interval. In this mount 3C, the glass beads 5A and 5B may or may not be embedded and fixed in the glass of the top portion 12 of the bulb 1 or the sealing portion 2.

FIGS. 4A and 4B are front views of discharge lamps L2 and L3 showing another embodiment of the present invention. In the above-described embodiment, the discharge lamp L1 sealed at one end has been described. However, this embodiment is applied to a lamp sealed at both ends, and the same reference numerals in FIG. The description is omitted.

The discharge lamp L2 shown in FIG. 4 (a) has sealing portions 2 and 2 at both ends of the bulb 1 in which lead wires 4 and 4 are sealed, respectively, and is connected to the end of each lead wire 4 and 4. The electrodes 6, 6 are arranged in parallel at predetermined intervals, and the tips of the electrodes 6, 6 are embedded in glass.

The lamp L2 shown in FIG. 4 (a) is mounted up and down like the mount shown in FIG. 2 (c), that is, the tip of one electrode 6 and the other lead wire 4 are connected to each other. Of the electrode 6 and one of the lead wires 4 are embedded and fixed in the glass beads 5A and 5B. Even if the respective glass beads 5A and 5B are embedded in the sealing portion 2, they remain in the internal space 11. There may be.

In the mount of the lamp L3 shown in FIG. 4B, the tip of the electrode 6 and the lead wire 4 are connected to a glass bead 5.
A and 5B are buried and fixed, but the respective glass beads 5A and 5B are in the space 11.

As described above, the lamps L2, L
3, the electrode 6 and the lead wire 4 are connected to the glass beads 5.
A and 5B are buried and fixed in each other, so that both electrodes 6 and 6 are arranged in parallel at a predetermined interval, so that the variation of the discharge starting voltage is small as in the above embodiment, and
A discharge lamp L2 having a large emission range and improved emission characteristics;
L3 can be provided.

FIGS. 5A to 5C show another embodiment of the present invention, in which discharge lamps L4 to L6 are sealed at one end.
In the figure, the same parts as those in FIGS. 1 and 4 are denoted by the same reference numerals, and description thereof will be omitted.

As described above, the metal oxide layer 7 made of aluminum oxide Al ₂ O ₃ or the like is formed on the surface of the electrode 6 of the discharge lamp, and the metal oxide layer 7 has an electrically insulating property. So that discharge does not occur at a low voltage.

However, the lead wire 4 holding and connecting the electrode 6
In the lamp manufacturing process, a slight oxide film is formed on the surface by increasing the temperature in the manufacturing process of the lamp, but has lower insulation and lower work function than the electrode surface coated with the metal oxide layer 7. For this reason,
Discharge may occur in the lead wires 4 and 4 having a lower work function than the electrode 6 fed through the lead wires 4 and 4 in the bulb 1, which is also a factor of increasing the variation of the discharge starting voltage. Was.

FIG. 5 shows a discharge lamp L4 shown in FIG. 5 (a) which is used to prevent discharge caused by the lead wire 4. The discharge lamp L4 shown in FIG. Is coated with a metal oxide layer 91 made of aluminum oxide Al ₂ O ₃ or the like. Of course, this metal oxide layer 91 is formed by immersing the electrodes 6, 6 and the leads 4, 4 in the metal oxide suspension, so that the layers 7, 91 covering the electrodes 6 and the leads 4 are formed. Are the same, and the surfaces of both the lead wires 4, 4 may be covered with the metal oxide layer 91.

In the discharge lamp L5 of FIG. 5B, an electric insulating layer 92 made of a low melting point glass containing a metal oxide is formed on the surface of one lead wire 4 located in the space 11 in the bulb 1. 5 (c), an electric insulating layer 92 made of low-melting glass is formed so as to continuously cover the surfaces of both lead wires 4, 4 located in the space 11 in the bulb 1. It is.

As shown in FIGS. 5A to 5C, since at least one of the lead wires 4 and the electrodes 6 is insulated, discharge between the other lead wires 4 and the electrodes 6 is achieved. Is less likely to occur and the variation of the discharge starting voltage can be reduced. Further, it is possible to provide the discharge lamps L4 to L6 in which the occurrence of discharge at the end inside the bulb 1 is prevented, and the emission characteristics are prevented from being reduced so that the emission range is narrowed.

In FIGS. 5A to 5C, not one lead wire 4 but a pair of two lead wires 4, 4
A metal oxide layer 91 and an electric insulating layer 92 may be formed on the upper surface of the bulb 1, as shown in FIG. Thus, the interval between the two electrodes 6, 6 may be fixed with high precision and firmly.

FIG. 6 is a graph showing the discharge lamps L1, L4, L5, L6 having the structure shown in the above embodiment and a pair of conventional lead wires fixed with bead glass and the electrode tips not fixed. The discharge start voltage of the lamp R is plotted, and the horizontal axis represents 20 lamps (×
The vertical axis indicates the discharge starting voltage V.

As is apparent from the graph, the lamp group of the present invention has a discharge starting voltage V
Was reduced to about half (50%).

The discharge lamps L1 to L6 having the structure of each of the above-described embodiments are incorporated for displaying the voltage of various instruments and electric devices, and perform the display of the discharge starting voltage with high accuracy with little error. be able to.

The present invention is not limited to the above embodiment. For example, the discharge lamp is not limited to a neon lamp (orange light emission), but may be a rare gas such as argon Ar (light purple light emission), xenon Xe (orange green light emission), helium (pink light emission) or the like according to a desired light emission color or voltage. It can be applied to various glow lamps filled with gas.

Further, a separate metal body is connected to the lead wire as the electrode. However, the present invention is not limited to this. When a single lead wire such as a nickel-plated dumet wire is used as the inside, outside, and sealing, the inside may be used. An electrode may be formed by forming a metal oxide layer on the surface of the lead wire.

[0056]

According to the first to third aspects of the present invention, since a pair of electrodes facing each other are arranged in parallel at a predetermined interval, the discharge interval can be set with high precision. And it can be secured firmly. In addition, the metal oxide layer formed on the surfaces of both electrodes is electrically an insulating layer, and does not cause undesired discharge at a low voltage between the adjacent electrodes, and particularly, damage of the metal oxide layer. Since the tip of the electrode, which is liable to cause the insulation and the insulation property is likely to be reduced, is buried in the glass, no discharge center is generated at the tip.

Accordingly, a discharge center is generated between substantially the center portions of the two electrodes, so that it is possible to provide a discharge lamp such as a neon lamp having a large luminous range, a small luminous range, and an improved luminous characteristic.

According to the fourth and fifth aspects of the present invention, the surface of at least one of the electrodes and the lead wires provided in the glass tube bulb is made of an electric metal oxide. By covering with an insulating layer, a discharge is hardly generated between the lead wire and the electrode on the other side, and a variation in a discharge starting voltage can be reduced. Further, it is possible to provide a discharge lamp having a large luminous range and improved luminous characteristics by preventing occurrence of discharge at an end portion in the bulb.

According to the structure of the sixth aspect of the present invention, the lamp formed in the sealing portion at one end of the bulb has the same effects as those of the first to fifth aspects. .

Further, according to the structure of the seventh aspect of the present invention, in the lamp formed in the sealing portion at both ends of the bulb, the same effects as those of the first to fifth aspects can be obtained. .

[Brief description of the drawings]

FIG. 1 is a sectional front view showing an embodiment of a discharge lamp according to the present invention.

2 (a) to 2 (c) are schematic front views of a discharge lamp mount according to the present invention.

FIG. 3 is a voltage display circuit diagram using a discharge lamp according to the present invention.

4A and 4B are front views showing another embodiment of the discharge lamp according to the present invention.

FIGS. 5A to 5C are sectional front views showing another embodiment of the discharge lamp according to the present invention.

FIG. 6 is a graph showing variations in the discharge starting voltage of the discharge lamp according to the embodiment of the present invention and the conventional discharge lamp.

[Description of References] L1 to L6: Discharge lamp 1: Glass tube bulb 2: Sealing part 3A to 3C: Mount 4: Lead wire 5A, 5B: Glass bead 6: Electrode 7, 91: Metal oxide layer 92: Electricity Insulating layer

Claims (7)

[Claims] 1. A glass tube bulb, a pair of lead wires sealed to a sealing portion at the end of the bulb, and a tip provided at a predetermined discharge interval facing the pair of lead wires. A discharge lamp comprising: a fixed electrode; a metal oxide layer coated on at least one surface of the electrode; and a discharge rare gas sealed in the bulb. . 2. The discharge lamp according to claim 1, wherein the tip portions of the pair of electrodes are embedded in the bulb. 3. The discharge lamp according to claim 1, wherein the pair of electrodes are fixed via an insulator. 4. A glass tube bulb, a pair of lead wires sealed at a sealing portion at an end of the bulb, and an electrode provided opposite to the pair of lead wires at a predetermined discharge interval. A discharge lamp comprising: a metal oxide layer formed on at least one electrode and a surface portion of a lead wire in a bulb; and a rare gas for discharge sealed in the bulb. 5. A glass tube bulb, a pair of lead wires sealed to a sealing portion at the end of the bulb, and an electrode provided opposite to the pair of lead wires at a predetermined discharge interval. A metal oxide layer formed on at least one surface of the electrode, a glass insulated from a surface of a lead wire in the bulb, and a discharge rare gas sealed in the bulb. A discharge lamp. 6. The discharge lamp according to claim 1, wherein a pair of lead wires is sealed to a sealing portion formed at one end of the glass tube bulb. 7. The discharge lamp according to claim 1, wherein lead wires are respectively sealed to sealing portions formed at both ends of the glass tube bulb.