JPS5931551A - Low pressure mercury vapor discharge lamp - Google Patents

Abstract

PURPOSE:To effectively use the power of plasma that is emitted from an opening to an outer tube and improve the efficiency of a lamp by providing a layer that applying a different phosphor from that of an inner tube to the outer tube. CONSTITUTION:The inner surface of inner tubes 2 and 3 is coated with a rare earth phosphor of 5mg/cm<2> in thickness. The inner surface of an outer tube 1 is coated with a halogenated phosphor for general illumination of 3mg/cm<2> in thickness. Since the temperature of the outer tube is lower than that of the inner tube and the density of plasma emitted from an opening is lower than that of the inner part of the inner tube, this purpose can fully be attained using an economical halogenated phosphor that is used normally without coating the inner surface of the outer tube with an expensive phosphor.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to low-pressure mercury vapor discharge lamps, and more particularly to improvements in one-sided capped fluorescent lamps, so-called compact fluorescent lamps.

An example of such a compact fluorescent lamp is one in which the discharge tube of a normal fluorescent lamp is made thin and bent and housed together with a lighting circuit in a tube having a shape similar to a light bulb. In such a lamp, the temperature of the discharge tube becomes higher than the optimum value, making it difficult to produce a lamp with a large output.
In order to maintain optimal mercury vapor pressure, techniques such as amalgam encapsulation are required.

A lamp disclosed in Japanese Unexamined Patent Publication No. 54-44370 is known as an example in which such problems are relatively rare. This lamp has a bent inner tube with an opening at one end and an electrode at the other end inside an airtightly sealed outer tube, and a discharge path leads from the opening in the inner tube to the outer tube. ing. Although the operating temperature of this lamp is relatively high at 1M degrees, the mercury vapor pressure for converting electric power into ultraviolet light is determined by the temperature of the coldest part of the outer bulb, and is characterized by being close to the optimum value.

The present invention aims to improve the efficiency of such lamps without significantly increasing the price of the lamp.

Therefore, in the present invention, in such a lamp, attention is paid to the plasma emitted from the opening of the inner bulb into the outer bulb, and this energy is effectively used. That is, in the lamp of the present invention, the inner surface of the outer bulb is also coated with a phosphor. However, the phosphor applied to the inner surface of the outer tube need not be the same as the phosphor applied to the inner surface of the inner tube.

The inner tube of such lamps has a high temperature due to the high current density and is exposed to intense ultraviolet radiation. For this purpose, the inner surface of the inner tube is coated with a phosphor that exhibits less temperature quenching and less deterioration due to short-wave ultraviolet irradiation. Although such fluorescent materials containing rare earth elements are known, they are expensive. In the present invention, the temperature of the outer tube to which the phosphor is newly applied is lower than that of the inner tube, and the density of the plasma emitted from the phosphor opening is also lower than that of the inner tube. There is no need to coat the inner surface of the outer tube with a commonly used inexpensive halo phosphor. Alternatively, even if the phosphor applied to the inner surface of the outer tube contains the same rare earth element as that applied to the inner tube, it is possible to produce the same effect by changing its composition.

Furthermore, a phosphor layer 1 applied to the outer tube close to the opening of the inner tube! In addition to receiving ultraviolet light emitted from the plasma and emitting visible light, the phosphor layer reflects the strong light emitted from the opening of the inner tube or the scattered light emitted in the direction of the cap. This makes it possible to make effective use of light that would otherwise be absorbed. to achieve the same purpose,
It is also effective to thin the phosphor layer applied to the tip of the lamp, apply it only to the inner surface of the outer tube near the opening of the inner tube, and place objects coated with phosphor near the opening. be. Furthermore, if the inner tube is made of a material that transmits ultraviolet light, the ultraviolet light that is normally absorbed by the glass of the inner tube is converted into visible light by the phosphor of the outer tube, further improving efficiency.

Hereinafter, the present invention will be explained by examples. FIG. 1 is a diagram showing the structure of a low-pressure mercury vapor discharge lamp according to the present invention. In the figure, 1 is an outer tube, which is evacuated and then filled with 3'l'' or r of mercury and argon gas.2 and 3 are two inner tubes, 4.5 is an electrode, 6, 7 is an opening. The inside of the inner tubes 2 and 3 communicates with the inside of the outer tube 1 via the opening 6.7. 8 is the base of the lamp, 9 is a storage part for the lighting circuit, and 10 is a base. Yes.The diameter of outer bulb 1 is 9
0mm, the diameter of inner tubes 2 and 3 is 101rrrn1, the length is 1
It is 30mm.

The distance between the center lines of the openings 6.7 of the two inner tubes 2, 3 is 30 mm.

In this embodiment, the inner tubes 2 and 3 have five rare earth phosphors on their inner surfaces.
It is applied to a thickness of mg/cm2. The inner surface of the outer tube 1 is coated with a general illumination phosphor to a thickness of 3 mg/cm' according to the invention. This lamp is lit with a power supply of 100V and 50Hz, and the tube voltage is 60V.
The luminous flux was 840 lumens when the lamp power was 17W. This was a 6% improvement compared to the case where the inner surface of the lamp was made of a light diffusing film.

As described above, according to the present invention, by providing the outer tube with a layer coated with a phosphor different from that of the inner tube, the electric power of the plasma emitted from the opening into the outer tube can be effectively used, and the lamp can be heated. This makes it possible to improve lamp efficiency with less increase in price.

The phosphor layer coated on the part of the outer tube facing the opening of the inner tube reflects the light emitted from the inner tube toward the base and makes it possible to use it effectively, increasing the efficiency of the lamp. Double the effect of improving.

By forming a phosphor 1- even at the tip of the lamp, where the light emitted is weak, the inside of the lamp becomes a negative image, the light from the inside is diffused, the uneven brightness is reduced, and a beautiful lamp that shines uniformly can be obtained. Is possible.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the structure of a low-pressure mercury vapor discharge lamp of the present invention. 1...Outer tube, 2.3...Inner tube, 4. Death...electrode, 6
,7 Figure 1! Continuing from page 1 (Inventor: Sei Murayama, Hitachi, Ltd. Central Research Laboratory, 1-280 Higashi-Koigakubo, Kokubunji City, Hitachi, Ltd., Shigeo Mikoshiba, 1-280 Higashi-Koigakubo, Kokubunji City) Inventor: Hiromitsu Matsuno, Hitachi, Ltd. Central Research Laboratory, 1-280 Higashikoigakubo, Kokubunji City

Claims (1)

[Scope of Claims] 1. An outer tube containing a rare gas and mercury, which is contained in the outer tube, has an opening at one end, an electrode at the other end, and has a phosphor film on the inner surface. In a low-pressure mercury vapor discharge lamp having a bent inner tube, a phosphor film is also provided on the inner surface of the outer tube, and the phosphor film is similar to the phosphor of the inner tube. A low-pressure wood-like vapor discharge lamp characterized by comprising a phosphor having a composition different from that of a membrane. 2. The low-pressure mercury vapor discharge lamp according to claim 1 is also characterized in that a phosphor film is provided on a portion of the outer tube that is close to the opening of the inner tube. A low-pressure mercury vapor discharge lamp. Aspect 3, % The low-pressure steam discharge lamp according to claim 1, characterized in that an object provided with a phosphor film is disposed opposite the opening of the inner tube. Controlled steam discharge lamp. 4. Any one of claims 1 to 3
2. The low-pressure mercury vapor discharge lamp according to item 1, wherein the inner portion 1 is made of an ultraviolet-transparent material.