JP2000113861A - Xenon fluorescent lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong the life of a xenon fluorescent lamp of this kind by preventing the contact between a central electrode and a phosphor layer, and preventing the damage of the phosphor layer. SOLUTION: A proper number of disks 8 each formed of an insulating member and having a through hole 8a through which a central electrode 6 passes are fixed in the radial direction and provided on the inner diameter of the glass tube 2 of this xenon fluorescent lamp 1. Nodes are provided on the vibration generated on the central electrode 6 by the disks 8 to reduce the amplitude, the resonance frequency of the central electrode 6 is increased, no resonance occurs by external vibration such as the vibration when an apparatus is operated, thereby the contact between the central electrode 6 and a phosphor layer 5 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a xenon fluorescent lamp used as an illuminating light source for reading an original of an electronic copying machine, and more particularly, to an improvement in the seismic resistance of the xenon fluorescent lamp. It is intended for.

[0002]

2. Description of the Related Art A conventional xenon fluorescent lamp 90 of this kind is used.
FIGS. 4 and 5 show an example of the configuration of the xenon fluorescent lamp 90. The xenon fluorescent lamp 90 has a glass tube 91 having two ends 9
The inside is sealed with xenon gas (not shown). On the outer diameter side of the glass tube 91, an external electrode 92 provided with an opening 92a along the axial direction of the glass tube 91 is formed.

A coil-shaped center electrode 93 is provided at a position substantially at the center of the inner diameter of the glass tube 91. The center electrode 93 is held by the stem 92 so as to maintain a predetermined position. ing. Further, the glass tube 9
1 has an opening 9 at the same position as the external electrode 92.
A phosphor layer 94 provided with 4a is provided. still,
The reference numeral 95 in the figure denotes a getter.

When a voltage is applied between the external electrode 92 and the center electrode 93 of the xenon fluorescent lamp 90 configured as described above, the phosphor layer 94 is excited by discharge generated between the electrodes 92 and 93, and emits light. The emitted light is extracted to the outside through the openings 92a and 94a to illuminate a target document.

[0005]

However, in the above-described conventional xenon fluorescent lamp 90, for example, A
To illuminate a 3-size original, the total length of the glass tube 91 is 3
About 60 mm is required, and the inner diameter of the glass tube at this time is set to about 8 mm, which is an extremely small value compared to the entire length.

Moreover, since the center electrode 93 has a coil shape, it is liable to bend due to vibration or the like. Particularly, when the vibration applied from the outside is close to the resonance frequency of the center electrode 93, the center electrode 93 is greatly bent even with a slight vibration. The phosphor layer 94 comes into contact with the phosphor layer 94, and the phosphor layer 94 is scraped off. As a result, the xenon fluorescent lamp 90 has a problem that its life is shortened.

Incidentally, if the measurement result by the inventor is described as a reference value, the vibration generated in a general electronic copier capable of copying A3 size paper is around a frequency of 65 Hz, and the strength of the vibration is the acceleration of gravity. The resonance frequency of the center electrode 93 is about 7.5 G in the case of the entire length of the glass tube 91, which is 57 to 73 Hz, and the occurrence of the above problem can be predicted with high probability. .

[0008]

According to the present invention, as a specific means for solving the above-mentioned conventional problems, an external electrode is disposed on an outer diameter of a glass tube, and a coil is disposed substantially at the center of the inner diameter of the glass tube. In a xenon fluorescent lamp in which a center electrode in a shape of a circle is arranged, an appropriate number of disks formed of an insulating member and provided with a through hole through which the center electrode passes are fixed in the inner diameter of the glass tube in the radial direction. It is an object of the present invention to provide a xenon fluorescent lamp characterized by being provided.

[0009]

Next, the present invention will be described in detail based on an embodiment shown in the drawings. 1 and FIG.
Is a xenon fluorescent lamp according to the present invention,
In the xenon fluorescent lamp 1, an external electrode 4 having an opening 4a is provided on an outer diameter side of a glass tube 2 whose both ends are sealed with a stem 3, and a phosphor layer 5 having an opening 5a is provided on an inner diameter side. The stem 3 is provided at the center of the glass tube 2.
Is provided with a coil-shaped center electrode 6 and a getter 7 as in the conventional example.

Here, in the present invention, a disk 8 is provided on the inner diameter of the glass tube 2, and the disk 8 is formed of an insulating and translucent member such as glass or ceramic. The outer diameter of the disk 8 is the same as that of the glass tube 2.
And a through hole 8a having a diameter necessary for penetrating the center electrode 6 is provided at the center.

Before the glass tube 2 is sealed at both ends, the disk 8 is bonded to a position substantially at the center in the longitudinal direction when the xenon fluorescent lamp 1 is completed as a low melting point glass or the like. Installed with agent. At this time, a phosphor layer 5 is provided on the inner diameter side of the glass tube 2.

Next, the operation and effects of the xenon fluorescent lamp 1 having the above configuration will be described. The provision of the disk 8 allows the center electrode 6 to be supported by the disk 8 at substantially the center of its length. Therefore, when the center electrode 6 vibrates, the disk 8 becomes a vibration node P as shown in FIG.

Therefore, the vibration generated at the center electrode 6 is generated at two places on both sides of the node P of the vibration, and the length of the center electrode 6 at one place is substantially halved. As a result, the amplitude becomes approximately half the amplitude W2 of the conventional example. In this embodiment, an example in which one disk 8 is used has been described. However, in actual practice, the number of disks 8 may be increased according to the length of the glass tube 2. .

At the same time, since the vibration node P is generated as described above, the resonance frequency of the center electrode 6 also becomes high. When the total length of the glass tube 2 is about 360 mm, the conventional center electrode The resonance frequency of 59 to 69 Hz in 6 increases to 135 to 145 Hz by providing the disk 8.

That is, in the xenon fluorescent lamp 1 of the present invention, the resonance frequency of the center electrode 6 is apart from, for example, 65 Hz, which is the frequency at which the mechanism of the electronic copying machine operates. Since the amplification is not performed, the amplitude generated at the center electrode 6 is drastically reduced, and the contact with the phosphor layer 5 is avoided.

[0016]

As described above, according to the present invention, an appropriate number of disks formed of an insulating member and provided with through holes through which the center electrode passes are fixed in the radial direction by the present invention. By providing the xenon fluorescent lamp provided, a node is provided in the vibration generated at the center electrode by the disk to reduce the amplitude, and the resonance frequency of the center electrode is also increased to prevent resonance due to external vibration, This prevents contact between the center electrode and the phosphor layer to prevent the phosphor layer from being damaged, and has an extremely excellent effect on extending the life of this type of xenon fluorescent lamp.

[Brief description of the drawings]

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

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

FIG. 3 is an explanatory diagram showing the operation of a xenon fluorescent lamp according to the present invention in comparison with a conventional example.

FIG. 4 is a sectional view showing a conventional example.

FIG. 5 is a sectional view taken along line BB of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Xenon fluorescent lamp 2 ... Glass tube 3 ... Stem 4 ... External electrode 4a ... Opening 5 ... Phosphor layer 5a ... Opening 6 ... Central electrode 7 ... Getter 8 ... Disc 8a: Through-hole

Continuation of the front page (72) Inventor Yasuhide Yasuda 30-1 Uehira, Hirakita Shirato, Iwaki-shi, Fukushima Prefecture (72) Inventor Hiroharu Shimada 3-23- 401, Susukino, Aoba-ku, Yokohama-shi, Kanagawa Prefecture

Claims (1)

[Claims] 1. A xenon fluorescent lamp in which an external electrode is disposed on an outer diameter of a glass tube and a coil-shaped center electrode is disposed substantially at the center of the inner diameter of the glass tube. A xenon fluorescent lamp, characterized in that an appropriate number of disks provided with through holes through which the center electrode passes are fixedly provided in the radial direction.