JPS6329937B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention comprises an outer tube filled with mercury and a rare gas as a discharge medium, and an inner tube with an electrode enclosed at one end. The present invention relates to a discharge lamp configured to form a path.

Various types of discharge lamps of this type have been proposed with the aim of reducing the size of the discharge lamps. FIG. 1 shows a typical example. That is, a disc-shaped stem 3 with an electrode 6 projecting thereon is provided with an inner tube 5 that is open on both sides so as to enclose the electrode 6 therein, and this stem 3 is further sealed to the outer tube 1. A discharge path regulated in a U-shape by an inner tube 5 is formed in an outer tube 1. In addition, 9 is a thin tube for exhaust. Therefore, the light source can be made compact to about half the tube length of a straight tube discharge lamp, and can be made similar in shape to a conventional incandescent light bulb.

However, due to the structure of the discharge lamp described above, the inner tube 5 is fixed to the stem 3, and then the stem 3 and the outer tube 1 are sealed together. In this case, usually the inner tube 5 and the stem 3
Since the glass frit 7 is used to fix the stem 3 to the outer tube 1, the heat causes the frit 7 to soften, causing the inner tube 5 to tilt, which impairs the product quality. As the water flows out, a gap is created between the stem 3 and the end face of the inner tube 5,
This creates an undesired discharge path between the electrodes 6. There were drawbacks such as causing so-called discharge short-circuit accidents.

This invention was made in view of the above drawbacks.
In an outer tube with an inner tube for regulating the discharge path, the inner tube with an electrode sealed at one end is inserted into the inner tube insertion hole formed in the stem, and in this state the inner tube and stem are connected. The abutting point is airtightly fixed to the outside, preventing the inner tube from tilting and impairing the product quality, and preventing gaps from forming between the inner tube and the stem, which prevents discharge short-circuit accidents. The idea is to provide electric light.

This invention will be explained below based on FIGS. 2 and 3. In the figure, reference numeral 1 denotes a cylindrical outer tube made of light-transmitting glass with an open bottom 2, and a predetermined amount of mercury and a rare gas serving as a discharge medium are sealed inside. 3
is a stem made of disk-shaped glass that can be welded to the outer tube 1, and is sealed to the bottom 2 of the outer tube 1 to make the outer tube 1 an airtight container.In the center, there are two inner tubes. An insertion hole 4 is formed. Reference numeral 5 denotes two straight inner tubes made of transparent glass, each having an electrode 6 hermetically sealed at one end and an open end. The body 51 is fixed to the inner tube insertion hole 4 of the stem 3 with a glass frit 7 so as to be airtight. Reference numeral 8 indicates a phosphor layer formed on the inner surface of the inner tube 5, 9 indicates a thin exhaust tube sealed to the stem 3 so as to communicate with the inside of the outer tube 1, and 11 indicates a phosphor layer formed on the inner surface of the inner tube 5 from each of the electrodes 6. A starter connected to one of the lead wires 10 led out, 12 a current limiting element connected to one of the other lead wires 10, 13 fixed to the bottom of the outer tube 1,
A cover body 14 housing the starter 11 and the current limiting element 12 inside is fixed to the end of the cover body 13, and is connected to the current limiting element 12 and the other lead wire 1.
0 and the remaining one, each cap is individually conductively connected to the other one. When AC power is applied from this base 14, as the starter 11 operates, a U-shaped discharge path A is formed inside the outer tube 1, which is bent inside the tip.
is formed.

In the discharge lamp configured in this way, the inner tube 5 has the electrode 6 sealed at one end, so that the stem 3
After the stem 3 is sealed to the outer tube 1, the other end of the stem 3 can be inserted from the outside into the inner tube insertion hole 4 and fixed to the stem 3. Therefore, the frit 7 that fixes the inner tube 5 to the stem 3 is not subjected to heat that would cause it to soften after solidification, and the inner tube 5 is reliably supported on the stem 3. In addition, since the electrodes 6 are sealed to each inner tube 5 without using individual frits 7, short-circuit accidents during discharge are greatly reduced. Furthermore, by appropriately selecting the location where the inner tube 5 and the stem 3 are fixed, it is possible to make the external shape more compact without changing the length of the discharge path A.

In the above embodiments, glass was used as the stem material, but the stem material is not limited to this. For example, copper metal, iron-nickel-chromium alloy, iron-chromium alloy, etc. There is nothing to prevent the use of metals that can be welded to glass.

Furthermore, good adhesion can be achieved by selecting an inorganic adhesive such as a low-melting point glass frit mainly made of lead borate or an adhesive mainly made of silicon for fixing the stem 3 and the inner tube 5. This has been confirmed.

Furthermore, the number and shape of the inner tubes 5 do not necessarily have to be two and have a straight shape as in the above embodiment, but two or more inner tubes 5 may also have a shape with some bends. Even if the above embodiment is implemented, the same effect as that of the above embodiment can be expected.

As explained above, the present invention has an inner tube disposed inside the outer tube to regulate the discharge path, the stem is provided with an inner tube insertion hole, and the inner tube is sealed with an electrode at one end. Since the tube is inserted into the inner tube insertion hole and is fixed to the stem so as to be airtight with the outside, the inner tube can be fixed to the stem after the stem is sealed to the outer tube, and therefore the stem and inner tube can be fixed to each other. Since the adhesive that fixes the inner tube to the inner tube can be prevented from softening, it is possible to prevent the inner tube from being tilted and the product quality is impaired, and it is also effective in greatly reducing short-circuit accidents in discharge.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional discharge lamp, FIG. 2 is an exploded perspective view showing an embodiment of the discharge lamp according to the present invention, and FIG. 3 is a sectional view showing the outer bulb and cover body separated. It is. In the figures, 1 is an outer tube, 2 is a bottom, 3 is a stem, 4 is an inner tube insertion hole, 5 is an inner tube, and 6 is an electrode. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A glass outer tube with an open bottom filled with mercury and a rare gas; the outer tube is sealed to close the bottom, and several inner tube insertion holes are formed. A discharge lamp comprising a stem, an inner tube that is inserted into the inner tube insertion hole in an airtight manner from the outside, has an electrode sealed at the bottom, and has a tip open inside the outer tube. 2. The discharge lamp according to claim 1, wherein the inner tube has a phosphor layer on its inner surface. 3. The discharge lamp according to claim 1 or 2, wherein the stem is made of a metal material that can be welded to the outer bulb. 4. The discharge lamp according to any one of items 1 to 3, wherein the inner tube and the stem are airtight with an inorganic adhesive. 5. The discharge lamp according to any one of claims 1 to 3, wherein the inner tube and the stem are airtight with an adhesive mainly composed of silicon.