JPH0794152A - Electrodeless discharge lamp - Google Patents

Abstract

PURPOSE:To prevent the fracture of an electrodeless discharge lamp due to a temperature rise by jointing a pair of symmetrical half-split annular glass tubes to each other at two positions to constitute an annular form. CONSTITUTION:Cylindrical glass tubes as a pair are respectively curved, thereby forming a pair of half-split annular glass tubes 7 symmetrical with each other, and the tubes 7 are jointed to each other at two positions via thermal deposition or the like. Thus, an electrodeless discharge lamp 5 becomes annular via a pair of joint sections 8. In this way, the lamp 5 is formed out of the glass tubes 7 jointed to each other and, therefore, even when the temperature of the discharge lamp 5 rises due to lighting and the glass tubes 7 expand, the extent of the expansion is equal at the two joint sections 8. Thus, high stress due to the expansion does not occur at the joint sections 8. Furthermore, stress due to the expansion can be dispersed over the two joint sections 8, thereby preventing the occurrence of a fracture.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrodeless discharge lamp formed in a ring shape without a terminal.

[0002]

2. Description of the Related Art In a discharge lamp lighting device, as shown in FIG. 6, an electrodeless discharge lamp 21 is formed in an annular shape without a terminal, and this is attached to an iron core 22 in a chain shape to obtain an electrodeless discharge lamp. There is a system in which a magnetic flux is linked to 21 and thereby a discharge lamp current is caused to flow through the electrodeless discharge lamp 21 to light the electrodeless discharge lamp 21, which is used in this type of discharge lamp lighting device. In the conventional electrodeless discharge lamp 21, one cylindrical glass tube is curved in an annular shape, and its ends are joined to each other (for example, Japanese Patent Application No. 4-5146).

[0003]

By the way, in the conventional case, when the temperature of the electrodeless discharge lamp 21 rises due to lighting of the discharge lamp, a large force is applied to the joint portion 23 of the electrodeless discharge lamp 21 due to expansion of the glass tube. , For this reason electrodeless discharge lamp 2
There was a problem that 1 was easily damaged from the joint 23.

In view of the above problems, the present invention is to prevent the electrodeless discharge lamp from being damaged due to a temperature rise.

[0005]

The technical means of the present invention for solving the above technical problem is to join a pair of symmetrical half-divided glass tubes 7 at two points so as to form an annular shape. It consists of

[0006]

[Operation] The temperature of the electrodeless discharge lamp rises due to lighting,
Even if the glass tube 7 expands, the two joints 8 are equalized, so that a large stress due to the expansion does not occur in the joint 8. Further, the stress due to the expansion can be dispersed at the two joints 8.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. In FIG. 1, 1 is an iron core, 2 is a primary coil, which is wound around the iron core 1, and a high frequency power source 3 is attached to the primary coil 2. By connecting them, magnetic flux is generated in the iron core 1. Reference numeral 5 denotes an electrodeless discharge lamp, which is formed in an annular shape without electrodes and without termination as shown in FIG. The electrodeless discharge lamp 5 has the same structure as a normal discharge lamp having electrodes for gas components, mercury, etc. inside the discharge tube, and the inside of the discharge tube is coated with a phosphor. In addition, the electrodeless discharge lamp 5 is attached to the iron core 1 in a chain shape so as to form a one-turn secondary coil, and the magnetic flux of the iron core 1 is based on the same principle as a transformer in a normal discharge lamp having electrodes. A discharge lamp current flows through the electrodeless discharge lamp 5 that intersects with the.

The electrodeless discharge lamp 5 is manufactured as follows. That is, the pair of cylindrical glass tubes 6 shown in FIG. 3 are respectively curved to form a pair of symmetrical half-divided glass tubes 7, and these half-divided glass tubes 7 are heat-welded together. Electrodeless discharge lamp 5 which is joined at two points by
Is formed into an annular shape through the pair of joint portions 8.

FIG. 4 shows another embodiment, which is a large-diameter cylindrical portion 11
A pair of half-divided annular glass tubes 7 having a pair of connecting tube portions 12 are joined to each other at two locations to form an electrodeless discharge lamp 5.
Is configured in a ring shape. The other points are the same as those of the above-mentioned embodiment. FIG. 5 shows another embodiment, in which the electrodeless discharge lamp 5 is formed in an overlapping annular shape so as to interlink with the magnetic flux of the iron core 1 more than once. Tube 7 Join two comrades at two points,
The electrodeless discharge lamp 5 has a ring shape.

[0010]

In the electrodeless discharge lamp of the present invention, a pair of symmetrical half-divided glass tubes 7 are joined together in an annular shape at two points. Even if the glass tube 7 rises and the glass tube 7 expands, the expansion is equal to the joints 8 at the two places, so that a large stress due to the expansion does not occur at the joints 8 and the stress due to the expansion does not occur at the two places. It can be dispersed in the joint portion 8, and therefore damage due to temperature rise of the electrodeless discharge lamp can be prevented.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a plan view of a pair of glass tubes before constituting the electrodeless discharge lamp.

FIG. 4 is a plan view showing another embodiment.

FIG. 5 is a perspective view showing another embodiment.

FIG. 6 is a perspective view showing a conventional example.

[Explanation of symbols]

 5 Electrode discharge lamp 7 Glass tube

Claims (1)

[Claims] 1. An electrodeless discharge lamp comprising a pair of symmetrical half-divided glass tubes (7) joined together in an annular shape at two points.