JPH04298954A - Fluorescent lamp - Google Patents

Abstract

PURPOSE:To prevent a short circuit between metal members at a seal section of the metal members and a glass member and prevent mis-lighting. CONSTITUTION:Through sections where pairs of lead wires 26a-27b penetrate metal caps 24a, 24b are airtightly sealed by glass beads 28 to form seal sections. Electric insulating films 30 made of a continuous film are fitted on inner faces of the metal caps 24a, 24b at the seal sections respectively.

Description

[Detailed description of the invention]

[Object of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent lamp having a sealing part for airtightly sealing a metal member and a glass member, and more particularly to a fluorescent lamp with an improved sealing part.

0003

2. Description of the Related Art Conventionally, as fluorescent lamps of this type, there are fluorescent lamps 1 and 11 shown in FIGS. After sealing metal caps 3a and 3b made of stainless steel or the like and evacuating the inside of the glass bulb 2, an appropriate amount of mercury and rare gas are sealed. A phosphor film 4 is coated on almost the entire inner peripheral surface of the glass bulb 2.

Further, a pair of left and right electrodes 5a, 5b are provided upright on the inner surface of each metal cap 3a, 3b.
A pair of lead wires 6a, 6b, 7 supporting a, 5b
The ends of each of the caps a and 7b are led out to the outside by passing through the melter caps 3a and 3b. The penetration parts of these metal caps 3a, 3b are glass beads 8a, 8b, 9a,
9b for airtight sealing.

There are two methods for sealing the metal caps 3a and 3b to the glass bulb 2: a method of adhering them by heating and melting frit glass or solder glass, and a method of attaching the metal caps 3a and 3b to the left and right opening ends of the glass bulb 2. There is a method of applying high-frequency induction heating to the metal caps 3a and 3b and melting and fusing the parts that come into contact with the high-temperature metal caps 3a and 3b.

On the other hand, the fluorescent lamp 11 is used for display or decoration, and as shown in FIG. 9, the upper end of the opening of a metal envelope 12 made of stainless steel or the like is successively widened into a rectangular tube shape in two steps. An upper step portion 12a and a lower step portion 12b are formed.

The envelope 12 has a cathode 1 on its inner bottom surface.
4 have been set up. In addition, the envelope 12 has, in its upper part,
For example, four light emitting chambers are formed by concentrically housing a tapered cylinder 15 having a substantially inverted truncated pyramid shape and housing a cross-shaped partition plate 16 concentrically within the tapered cylinder 15.

Column-shaped anodes 17 are arranged in each light-receiving chamber, and the tips of anode lead wires 18 connected to each anode 17 are passed through the bottom of the lower step 12b of the envelope 12 in the vertical direction. The penetrating portion is hermetically sealed with spherical glass beads 19.

A face plate 20 made of glass or the like is fitted and fixed in the upper step 12a of the envelope 12.

0010

[Problems to be Solved by the Invention] However, in the fluorescent lamp 1 shown in FIG.
Since the outer surface of the glass bulb 2 is exposed to the outside air, the mercury inside the glass bulb 2 gradually moves to the metal caps 3a and 3b, and the lead wires 6a to 7b of each pair are passed through the metal caps 3a and 3b. There is a problem in that each pair is electrically shorted.

Furthermore, in the conventional fluorescent lamp 11 shown in FIG. 9, each anode lead wire 18 may be electrically shorted to the bottom of the lower step portion 12b of the envelope 12 for the same reason.

[0012] Conventionally, therefore, a glass coating 13 is applied to almost the entire inner peripheral surface of the envelope 12 as an electrically insulating coating.

However, even in this case, when the entire envelope 12 is heated at a slightly higher temperature in order to heat and melt the glass beads 19 and fuse them to the bottom of the lower step portion 12b, the glass component of the glass coating 13 is heated. There is a problem in that it evaporates and adheres to the anode 17 and anode lead wire 18, forming an insulating layer and causing non-lighting.

[0014] The present invention has been made in consideration of the above circumstances, and its purpose is to coat an electrically insulating coating consisting of a continuous coating on the inner surface of a metal member near the sealing portion with a glass member. Therefore, it is an object of the present invention to provide a fluorescent lamp that can prevent short-circuits between lead wires and non-lighting. [Structure of the invention]

[0015]

[Means for Solving the Problems] In order to solve the above problems, the present invention is constructed as follows.

The invention according to claim 1 of the present application (hereinafter referred to as the first invention) is a fluorescent lamp having a sealing part for airtightly sealing a glass member and a metal member, wherein the sealing part of the metal member is It is characterized by having an electrically insulating coating made of a continuous coating applied to the inner surface around the part.

[0017] The invention according to claim 2 of the present application (hereinafter referred to as the second invention) is such that the electrically insulating coating according to claim 1 is formed by applying a metal alkoxide solution to the inner surface of the metal member in the sealing part. It is characterized by being fired in the atmosphere.

[0018]

[Operation] <First invention> The inner surface of a pair of metal members such as lead wires placed close to each other around the sealed portion with the glass member is insulated by an electrically insulating film made of a continuous film.

Therefore, even if mercury adheres to the pair of metal members, it is possible to prevent the metal members from shorting out.

Furthermore, even if the glass member at the sealing part with the metal member is heated to a high temperature and tries to melt and evaporate, the electrically insulating film is a continuous film, so the glass component will evaporate and pass through. can be prevented from doing so.

[0021] Therefore, it is possible to prevent the glass component from adhering to metal members such as electrodes, forming an insulating layer, and causing non-lighting.

[Second invention] The metal alkoxide solution applied to the inner surface of the sealed portion of the metal member with the glass member is fired in the atmosphere to form an alumina coating.

[0023] Since this alumina coating is an electrically insulating coating made of a continuous coating, it exhibits the same effects as the first invention.

[0024]

[Embodiments] Hereinafter, embodiments of the first and second inventions of the present application will be explained based on the drawings.

FIG. 2 is an external perspective view of a first embodiment of the first invention of the present application, and FIG. 3 is a partially cut away longitudinal sectional view thereof.

In the figure, a fluorescent lamp 21 has, for example, a cylindrical glass bulb 22 whose opening ends in the axial direction are made airtight by metal caps 24a, 24b made of stainless steel or the like, on which a pair of left and right electrodes 23a, 23b are respectively provided. The pair of electrodes 23a and 23b are sealed and enclosed within the glass bulb 22.

The glass bulb 22 has approximately the entire inner peripheral surface.
Two pairs of lead wires 26a, 26b, 27a, which are coated with a phosphor film 25 and support both ends of each electrode 23a, 23b.
27b, each penetrating portion passing through each metal cap 24a, 24b is hermetically sealed by each glass bead 28, forming a sealed portion 29, respectively.

The inner surfaces of the metal caps 24a and 24b around the sealing portions 29 are each coated with an electrically insulating coating 30, which is a continuous coating, as shown in FIG.

As an example of a method for forming the electrically insulating film 30, first, an aluminum alkoxide solution is applied to the inner surfaces of the metal caps 24a and 24b by, for example, dipping.

Next, after drying this, the aluminum alkoxide is oxidized and decomposed by oxidizing and decomposing the aluminum alkoxide as shown in the following formula by baking it in the air at, for example, about 600°C for about 5 minutes, and the alumina film, which is a metal oxide film, is formed. There is a way to form it.

[0031] Heating Al2 [RO]3 +O2 →
Al2 O3 +CO2 +H2 O Therefore,
Since each pair of lead wires 26a and 26b, 27a and 27b are electrically insulated by electrically insulating coatings 30, 30, mercury is absorbed into these lead wires 26a and 26a.
Even if it adheres to 27b, short circuit between these can be prevented.

Furthermore, since the electrically insulating coatings 30, 30 are continuous coatings, even if the temperature is set to a high level in order to fuse the metal caps 24a, 24b to the glass bulb 22,
It is possible to prevent the glass component from evaporating and passing through the electrical insulation coating 30.

Therefore, it is possible to prevent glass components from adhering to the pair of electrodes 23a and 23b and forming an insulating layer, thereby preventing non-lighting.

The first and second inventions of the present application can also be applied to the fluorescent lamps 41 for display purposes shown in FIGS. 4 to 7.

In this fluorescent lamp 41, the penetration portion where each anode lead wire 18 vertically passes through the bottom of the lower step portion 12b of the envelope 12 is hermetically sealed with a spherical glass bead 19. The feature is that an electrically insulating coating 42 is deposited on the glass coating 13 of the lower step portion 12b, and other than this, the fluorescent lamp 11 is almost the same as the conventional fluorescent lamp 11 shown in FIG. 7, parts common to those in FIG. 9 are given the same reference numerals, and explanations of the overlapping parts are simplified or omitted.

The electrically insulating film 42 is a continuous film formed in the same manner as the electrically insulating film 30 of the first embodiment, and is made of, for example, an alumina film.

Therefore, in order to heat and melt the glass beads 19 and fuse them to the bottom of the lower step portion 12b, the envelope 1 is
When the whole of 2 is heated at a slightly higher temperature, the glass coating 13
The glass component evaporates, but since each electrically insulating coating 42 is a continuous coating, this glass component evaporates into the electrically insulating coating 42.
cannot be passed through.

[0038] Therefore, it is possible to prevent the glass component from adhering to the anode 17 and forming an insulating layer, thereby preventing non-lighting.

Note that the tapered tube 16 shown in FIGS. 4 to 7 may be made of an insulator such as glass or ceramics.

[0040] That is, excluding the face plate 20 etc.
If almost the entire conventional fluorescent lamp 11 is made of metal,
Stray capacitance increases.

As this stray capacitance increases, the anode 17
The fine discharge that assists in starting the main discharge between the electrode 14 and the cathode 14 cannot be maintained with a predetermined current, for example 10 μA, and requires a current larger than this fine discharge current, for example 20 to 30 μA.

When this slight discharge current increases, the cathode 1
As the glow discharge around 4 expands, the level of stray light increases.

[0043] As a result, the contrast deteriorates, resulting in a decrease in visibility.

Furthermore, if a lamp voltage is applied between the cathode 14 and the anode 17 without maintaining a slight discharge between them to light the cathode 14 and anode 17, the cathode 14
This has the disadvantage of causing sputtering and shortening the lamp life.

Therefore, by constructing the tapered tube 16 with an insulating tube, the stray capacitance of the fluorescent lamp 41 can be reduced and the slight discharge current can be reduced.

For this reason, it is possible to reduce the glow around the cathode 14, lower the level of stray light, and increase contrast, thereby increasing visibility.

[Effects of the Invention] As explained above, the present invention provides the following advantages:
Since the electrically insulating film made of a continuous film is applied, the metal member can be insulated.

[0048] Therefore, short circuits between metal members can be prevented.

Furthermore, since the electrically insulating film is a continuous film, even if the glass component evaporates due to heating of the sealed portion, this glass component cannot pass through the continuous electrically insulating film. Therefore, it is possible to prevent the glass component from evaporating and adhering to the electrode of the metal member to form an insulating layer, thereby preventing the non-lighting from occurring.

[Brief explanation of drawings]

FIG. 1 is an enlarged vertical cross-sectional view of the main part of FIG. 2;

FIG. 2 is an external perspective view of an embodiment of a fluorescent lamp according to the first invention of the present application.

FIG. 3 is a partially cutaway vertical cross-sectional view of FIG. 2;

FIG. 4 is an external perspective view of another embodiment of the fluorescent lamp according to the first invention of the present application.

FIG. 5 is an exploded perspective view of the embodiment shown in FIG. 4;

FIG. 6 is a view taken along the VI arrow in FIG. 4;

FIG. 7 is a sectional view taken along line VII-VII in FIG. 6;

FIG. 8 is a partially cutaway vertical sectional view of a conventional example.

FIG. 9 is a longitudinal sectional view of another conventional example.

[Explanation of symbols]

21, 41 Fluorescent lamp 22 Glass bulbs 23a, 23b A pair of electrodes 24a, 24b A pair of metal caps 26a to 27
b Lead wire 28 Glass beads 30, 42 Electrical insulation coating

Claims (2)

[Claims] 1. A fluorescent lamp having a sealing part that airtightly seals a glass member and a metal member, wherein an electrically insulating coating made of a continuous film is applied to the inner surface of the metal member around the sealing part. A fluorescent lamp characterized by: 2. The fluorescent lamp according to claim 1, wherein the electrically insulating coating is formed by applying a metal alkoxide solution to the inner surface of the metal member in the sealing portion and baking it in the atmosphere.