JPH0590803U - Fluorescent lamp - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a fluorescent lamp with improved safety against high voltage applied to the first and second external electrodes. [Structure] 1 is an envelope made of a glass bulb, and a light emitting layer 2 is attached to an inner surface of the envelope so as to form an aperture portion 2a. First and second external electrodes 3 and 4 made of aluminum tape are fixed to the outer surface of the envelope 1 so as to face each other along the axial direction. Then, the first and second leads 5 and 6 for connection with an external circuit are connected to the ends of the first and second external electrodes 3 and 4, respectively. On the other hand, a coating layer 7 made of a glass bulb is formed on the outer surface of the envelope 1 so as to cover the main parts of the first and second external electrodes 3 and 4.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a fluorescent lamp, and more particularly to an aperture type fluorescent lamp having a pair of external electrodes on the outer surface of an envelope.

[0002]

[Prior Art]

 A conventional fluorescent lamp of this type is configured, for example, as shown in FIGS. That is, A is an envelope made of a glass bulb, and a light emitting layer B having an aperture portion B1 is formed on the inner surface thereof. On the outer surface of the envelope A, first and second external electrodes C 1 and D 2 made of aluminum tape are attached and fixed along the axial direction. Then, on the outer surface of the envelope A, a heat-shrinkable resin tube E is arranged so as to cover the first and second external electrodes C and D after being covered with a silicon varnish.

In this fluorescent lamp, when a high frequency high voltage is applied to the first and second external electrodes C and D, the rare gas in the envelope is discharged and visible light is emitted from the aperture part B1. .. The light emitted from the aperture part B1 is suitable as, for example, a light source for an image scanner or a fax because the light is converged by the aperture part B1.

[0004]

[Problems to be solved by the device]

 However, this fluorescent lamp has to apply a high voltage of, for example, about 1 to 2 KV to the first and second external electrodes C and D in order to excite the rare gas in the envelope. It is necessary to ensure safety during use. For this reason, the outer surface of the envelope A is covered with the heat-shrinkable resin tube E, but since the adhesion between the resin tube E and the envelope A cannot be sufficiently secured, the humidity is high. If this happens, a creeping discharge will occur between the outer electrodes C and D along the envelope A, and it is difficult to ensure sufficient safety.

Therefore, an object of the present invention is to provide a fluorescent lamp having a relatively simple structure, capable of preventing a creeping discharge between external electrodes and improving safety.

[0006]

[Means for Solving the Problems]

 Therefore, according to the present invention, in order to achieve the above-mentioned object, an envelope having a light emitting layer on an inner surface thereof, and a first and second envelope formed on an outer surface of the envelope apart from each other along an axial direction thereof. It is characterized in that it is provided with an external electrode and a coating layer formed of a heat resistant member so as to cover the main parts of the first and second external electrodes on the outer surface of the envelope. A second invention of the present invention is characterized in that the coating layer is formed of a glass bulb or ceramics. A third invention is characterized in that the first and second external electrodes are formed of aluminum tape. A fourth invention is characterized in that first and second leads are connected to the first and second external electrodes.

[0007]

【Example】

 Next, an embodiment of the present invention will be described with reference to FIGS.

In the figure, reference numeral 1 denotes an envelope, which is composed of, for example, a glass bulb and a ceramic bulb. A light emitting layer 2 containing a phosphor is formed on the inner surface of the envelope 1. The light emitting layer 2a is partially formed with an aperture portion 2a so that the emitted light is converged. The inner space of the envelope 1 is filled with, for example, a rare gas whose main component is xenon gas. On the other hand, on the outer surface of the envelope 1, first and second outer electrodes 3, 4 made of aluminum tape, for example, are attached and fixed in the tube axial direction so as to face each other. In addition to the aluminum tape, the external electrodes may be formed by spraying a metal such as aluminum or copper by thermal spraying. Then, first and second leads 5 and 6 for connection to an external circuit are connected to the ends of the external electrodes 3 and 4 by soldering or the like. Further, a coating layer 7 is formed on the outer surface of the envelope 1 so as to cover the main parts of the first and second external electrodes 3, 4. The coating layer 7 is composed of a heat resistant member such as a glass bulb, but may be composed of ceramic or the like, or may be formed excluding the end portion of the envelope 1. In particular, the coating layer 7 is formed in close contact with the envelope 1 by heating the envelope 1 after covering the envelope 1 with a glass bulb. As the glass bulb, lead glass having a low softening point is suitable.

It should be noted that the present invention is not limited to the above-mentioned embodiment at all, and for example, the aperture part of the light emitting layer may be omitted, or the light reflecting layer having the aperture part may be formed. Further, the coating layer may be covered with a glass bulb and heated, or a glass material may be deposited and formed by thermal spraying.

[0010]

[Effect of the device]

 As described above, according to the present invention, since the outer surface of the envelope is adhered and covered with the heat resistant member, the influence from the external environment is mitigated and the creeping discharge between the external electrodes can be reduced. Therefore, the safety can be significantly improved. In particular, when a glass bulb is used as the coating layer, the decrease in light transmittance due to the deterioration of ultraviolet rays can be significantly improved as compared with the conventional heat-shrinkable resin tube.

[Brief description of drawings]

FIG. 1 is a partial front sectional view showing a first embodiment of the present invention.

FIG. 2 is a side sectional view of FIG.

FIG. 3 is a front view of a conventional example.

FIG. 4 is a side sectional view of FIG.

[Explanation of symbols]

 1 Envelope 2 Light Emitting Layer 2a Aperture Part 3 First External Electrode 4 Second External Electrode 5 First Lead 6 Second Lead 7 Covering Layer

Claims (4)

[Scope of utility model registration request] 1. An envelope having a light emitting layer on an inner surface thereof, and first and second envelopes formed on the outer surface of the envelope so as to be separated from each other along an axial direction thereof.
It is characterized in that it is provided with a second external electrode and a coating layer formed of a heat-resistant member so that an outer surface of the envelope is coated with main parts of the first and second external electrodes. Fluorescent lamp. 2. The fluorescent lamp according to claim 1, wherein the coating layer is formed of a glass bulb or ceramics. 3. The fluorescent lamp according to claim 1, wherein the first and second external electrodes are formed of aluminum tape. 4. The first and second external electrodes are provided on the first and second external electrodes.
The lead according to claim 1 is connected to the fluorescent lamp.