JP2000188088A - Fluorescent lamp for indicator light - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a change of a luminance by generating an electric discharge between a hot cathode and an anode over the full length of the hot cathode under a uniform condition. SOLUTION: In this lamp, a hot cathode 3 is hung across two lead wires 2a, 2a', while a nearly square plate-shaped anode 4 is attached to the other lead wire 2a" such that the anode 4 is disposed nearly parallel to the hot cathode 3 in a view of a plane perpendicular to the optical axis of the lamp and disposed at an angle of almost 45 degrees to the hot cathode 3 in a view of a plane parallel to the optical axis of the lamp. Thereby, an electric discharge between the hot cathode 3 and the anode 4 occurs over the full length of the hot cathode 3 under a uniform condition so that no change of a luminance occurs and a service life is elongated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent lamp, and more particularly, to an SFL (Subminiature Fluore).
It is also referred to as a "scent lamp", and has a power supply terminal at only one end, and relates to a configuration of a fluorescent lamp shaped for a general display lamp such as an incandescent lamp.

[0002]

2. Description of the Related Art Examples of the configuration of a conventional fluorescent lamp for an indicator lamp are shown in Japanese Utility Model Publication No. 4-43963 and Japanese Utility Model Publication No. 4-439.
64, Jpn. Since these operations are all the same, an example will be described with reference to FIGS. The stem 91 of the fluorescent lamp 90 has three lead wires 91a, 91a 'and 91a ", and two of the wires 91a and 91a' are filaments coated with an electron-emitting substance 92a. The remaining one 91a ″ is used to support the cathode 92, and
Is used to support an anode 93 provided in parallel with the anode 93.
Further, the hot cathode 92 and the anode 93 have a phosphor 9
4a is covered with a coated valve 94, and this valve 94
Is exhausted and then filled with gas and mercury to form a fluorescent lamp 90 for an indicator lamp.

When the fluorescent lamp 90 for a display lamp is turned on, a voltage of 5 VDC is applied to both ends of the hot cathode 92 to emit electrons, and the hot cathode 92 and the anode 9 are turned on.
A voltage of 24 VDC is applied between the electrodes 3 to discharge thermoelectrons emitted from the hot cathode 92 toward the anode 93. The discharge excites the phosphor 94a to emit light.

[0004]

However, in the above-described conventional fluorescent lamp 90 for a display lamp, the hot cathode 92 and the anode 93 are provided in parallel. As shown, the end S on the ground side of the hot cathode 92 at the position where the potential difference from the anode 93 is the largest.
The discharge position is set to the midpoint T due to deterioration of the electron-emitting substance 92a as the lighting time elapses.
Move to the side.

At this time, since a voltage of 5 V is applied to the hot cathode 92, the midpoint T has a potential that is approximately 2.5 V higher than the end S on the ground side, and the potential of the hot cathode 92 and the anode 93 is high. The potential between them drops by about 2.5 V, which causes a decrease in the discharge current and a decrease in the brightness of the fluorescent lamp for indicator lamps.

[0006] When the time further elapses, the discharge position should go to the end U on the high potential side of the hot cathode, but after passing through the middle point, the discharge further moves and the discharge becomes difficult to occur. That is, the voltage at which the discharge occurs is proportional to the distance (E∝LE:
After the discharge potential difference L (distance between discharges) has passed the midpoint T, the distance between discharges increases, while the potential difference decreases, so that discharge is less likely to occur. Therefore, U
There must be a service life until it reaches the point, but it can be used only up to T, and there is a problem that the service life is often shortened.

[0007]

According to the present invention, as a specific means for solving the above-mentioned conventional problems, there is provided a hot cathode which is a filament coated with an electron-emitting substance and an appropriate distance from the hot cathode. In the fluorescent lamp for an indicator lamp, the anode provided in this manner is attached to three lead wires penetrating the stem, the hot cathode is erected on two of the lead wires, and one of the remaining lead wires is The plate-shaped anode, which is substantially a quadrilateral, is substantially parallel to the hot cathode when viewed in a plane orthogonal to the optical axis of the lamp, and is parallel to the hot cathode in a plane parallel to the optical axis of the lamp. An object of the present invention is to provide a fluorescent lamp for an indicator light, wherein the fluorescent lamp is mounted at an inclination of about 45 degrees.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail based on an embodiment shown in the drawings. 1 and 2 is a fluorescent lamp for an indicator lamp (hereinafter, referred to as a fluorescent lamp 1) according to the present invention. 2a "are provided for supporting the hot cathode 3, which is a filament coated with the electron-emitting substance 3a, and the other 2a" is used for the anode 4. The point used for the support is the same as that of the conventional example except for the mutual angle between the hot cathode and the anode.

The hot cathode 3 and the anode 4 are covered with a bulb 5 having an inner surface coated with a phosphor 5a. The inner surface of the bulb 5 is evacuated and then filled with gas and mercury. This is the same as the conventional example.

The anode 4 having the above-mentioned shape is formed in a substantially quadrangular plate shape, and is attached to the lead wire 2a "by an appropriate means such as spot welding. At this time, the lead wire 2a" is used. Of the anode 4 does not protrude toward the hot cathode 3 beyond the upper side 4a of the anode 4.

The positional relationship between the hot cathode 3 and the anode 4 is such that when the anode 4 is viewed in a plane orthogonal to the optical axis of the lamp, the plane is substantially parallel to the hot cathode 3 and parallel to the optical axis of the lamp. Are mounted at an inclination of about 45 degrees with respect to the hot cathode. That is, the anode 4 is shaped like a flag hanging obliquely with the portion connected to the lead wire 2a "facing upward.

A mercury alloy is attached to one surface of the anode 4 by coating or the like, and a getter material such as Zr or Al is attached to the other surface as in the conventional example.

With the above-described structure, the fluorescent lamp 1 of the present invention has a high electric field strength because the anode 4 is formed of a plate member, and is generated on the hot cathode 3 coated with the electron-emitting substance 3a. The cathode spot (bright spot) becomes smaller. As a result, the temperature of the cathode spot rises, the efficiency of the emission of thermoelectrons is improved, and a large amount of cumulative ionization occurs, the amount of ultraviolet radiation emitted is increased, and the luminous efficiency of the fluorescent lamp 1 is improved.

The positional relationship between the hot cathode 3 and the anode 4 is such that when the anode is viewed from a plane perpendicular to the optical axis of the lamp, the surface is substantially parallel to the hot cathode and parallel to the optical axis of the lamp. Are mounted at an inclination of about 45 degrees with respect to the hot cathode. That is, since the anode 4 is shaped like a flag hanging obliquely with the portion connected to the lead wire 2a "facing upward, the hot cathode 3 and the upper side 4a of the anode 4 are formed as shown in FIG. The greater the distance between the hot cathode 3 and the anode 4, the greater the potential difference, so that the discharge conditions are the same between the hot cathode 3 and the anode 4 at any point.

That is, even if the spot point moves on the hot cathode, the discharge under the same condition occurs, and the brightness becomes the same throughout the life. In addition, the disadvantage that the spot point after the middle point on the hot cathode is not moved as in the conventional example is eliminated, and discharge is performed over the entire hot cathode, thereby extending the life.

At this time, the anode is attached at an angle of about 45 degrees with respect to the hot cathode in a plane parallel to the optical axis of the lamp, and then, at the end farthest from the lead wire, in parallel with the hot cathode. If provided, this portion is most likely to cause discharge, and discharge is started from here, which is convenient.

FIG. 4 shows another embodiment of the present invention, in which the lead wire 2a or 2a 'to which the hot cathode 3 is attached is the anode 4 or the lead wire 2a supporting the anode. A part of the lead wire 2a and / or 2a 'is curved outward so as not to be too close to "" to cause a discharge at this portion.

FIG. 5 shows a third embodiment of the present invention. In this embodiment, the anode 6 is corrugated so that a corrugation appears on the upper side 6 a facing the hot cathode 3. ing. By doing so, the anode 6 has an increased surface area at the same projected area. Therefore, since the projected area can be reduced if the surface area is the same, the anode 6 for holding the required amount of the mercury alloy can be further downsized, which contributes to downsizing of the fluorescent lamp.

[0019]

As described above, according to the present invention, a hot cathode is provided on two of the lead wires, and a substantially square plate-like anode is provided on one of the remaining lead wires with respect to the optical axis of the lamp. When viewed in a plane orthogonal to the hot cathode, and in a plane parallel to the optical axis of the lamp, approximately 45
Since the lamps are attached with a degree of inclination, the discharge between the hot cathode and the anode is performed under the same conditions over the entire length of the hot cathode, so that the luminance does not change.

At the same time, since the discharge is performed over the entire length of the hot cathode, the life is extended.

Since the anode is formed in a thin plate shape, the amount of thermionic emission of the cathode spot generated in the hot cathode can be increased, and the brightness of the fluorescent lamp can be improved.

In addition, since the anode is square and its upper side is corrugated, the size of the anode can be reduced, and the size of the fluorescent lamp can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view in the optical axis direction showing an embodiment of a fluorescent lamp for an indicator lamp according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a diagram showing a potential distribution between a hot cathode and an anode according to the present invention.

FIG. 4 is a sectional view in the optical axis direction showing a second embodiment of a fluorescent lamp for an indicator lamp according to the present invention.

FIG. 5 is a view of an anode part showing a third embodiment of a fluorescent lamp for an indicator light according to the present invention.

FIG. 6 is a sectional view in the optical axis direction showing an embodiment of a fluorescent lamp for an indicator lamp showing a conventional example.

FIG. 7 is a diagram showing a potential distribution between a hot cathode and an anode in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fluorescent lamp for indicator lights 2 ... Stem 2a, 2a ', 2a "... Lead wire 3 ... Hot cathode 3a ... Electron-emitting substance 4, 6 ... Anode 4a, 6a ... Top side of anode 5 ... … Bulb 5a… Phosphor Z …… Optical axis of the bulb

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[Procedure amendment]

[Submission date] January 8, 1999 (1999.1.8)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

FIG. 3

Claims (3)

[Claims] An indicator lamp comprising a hot cathode, which is a filament coated with an electron-emitting substance, and an anode provided at an appropriate distance from the hot cathode, attached to three lead wires passing through a stem. In the fluorescent lamp for use, the hot cathode is erected on two of the lead wires, and one of the remaining lead wires has a substantially quadrilateral plate-shaped anode orthogonal to the optical axis of the lamp. A fluorescent lamp for an indicator lamp characterized in that the fluorescent lamp is mounted at a plane substantially parallel to the hot cathode and parallel to the optical axis of the lamp at an inclination of about 45 degrees with respect to the hot cathode. 2. The anode is mounted at an angle of about 45 degrees with respect to the hot cathode in a plane parallel to the optical axis of the lamp, and is parallel to the hot cathode at an end furthest away from the lead wire. The fluorescent lamp for an indicator lamp according to claim 1, wherein the fluorescent lamp is provided for a display lamp. 3. The fluorescent lamp according to claim 1, wherein the anode is corrugated so that a wave shape appears on the upper side.