JP2011175813A - Low-pressure mercury discharge lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-pressure mercury discharge lamp achieving, in a wide temperature range, higher light emitting efficiency that depends on the temperature of its coolest portion. <P>SOLUTION: The low-pressure mercury discharge lamp includes rare gas and a light emitting metal filled in a discharge space 13 of a U-shaped air-tight container 11. At least 500W power is input thereto with such high current density that there is a relationship of IL/ϕin>0.05 between a lamp current IL and an inner diameter ϕin of the air-tight container. In a space 281 which is communicated with the discharge space 13 at the U-shaped front end of the air-tight container 11 to serve as the coolest portion of the air-tight container 11 outside the discharge space, a capsule 28 is formed having a connection hole 282 in which an amalgam 30 can be held. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a low-pressure mercury discharge lamp used for applications such as sterilization in which the luminous efficiency depending on the coldest part temperature is increased over a wide temperature range.

  In the conventional low-pressure mercury discharge lamp, the electrode part of the arc tube is fixed with a metal block and a metal plate, and the temperature-adjusted gas from a gas temperature control device or the like is blown to the rear part of the electrode, thereby cooling the arc tube at its coldest temperature. The temperature of the part is set to a predetermined value. (For example, Patent Document 1)

JP 2001-135486 A

  Since the technique of Patent Document 1 described above requires a gas temperature adjusting device from the necessity of cooling to around 25 ° C. in order to suppress a decrease in luminous efficiency when used as a sterilizing lamp, There is a problem that a means for controlling this is necessary and the system becomes complicated.

  An object of the present invention is to provide a low-pressure mercury discharge lamp capable of improving the luminous efficiency depending on the temperature of the coldest part in a wide temperature range.

  In order to solve the above-described problems, in the low-pressure mercury discharge lamp of the present invention, a rare gas is sealed in a discharge space in a U-shaped airtight container, and the lamp current IL and the inner diameter φin of the airtight container are IL / φin>. In a low-pressure mercury discharge lamp having a current density of 0.05 and at least an input power of 500 W, the amalgam is connected to the discharge space and is the coldest part of the hermetic vessel outside the discharge space. It is characterized by having a capsule capable of holding.

  According to this invention, while forming the coldest part without taking measures such as cooling, high luminous efficiency in a wide temperature range can be realized by using amalgam as the encapsulated chemical.

It is the schematic block diagram which notched and showed one part for demonstrating one Embodiment regarding the low pressure mercury discharge lamp of this invention. It is a block diagram for demonstrating the electrode of FIG. It is the partially cutaway sectional view which expanded and showed the principal part of FIG. It is explanatory drawing for demonstrating the effect of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  1 to 3 are diagrams for explaining an embodiment of the low-pressure mercury discharge lamp according to the present invention. FIG. 1 is a schematic configuration diagram with a part cut away, and FIG. 2 is an electrode portion of FIG. FIG. 3 is a partially cutaway cross-sectional view showing an enlarged main part of FIG. 1.

  1 to 3, reference numeral 11 denotes an airtight container including a U-shaped ultraviolet light transmissive and heat resistant tubular discharge space 13 having a bent portion 12 formed at an intermediate portion. The hermetic container 11 is made of, for example, quartz glass. Electrodes 14 and 15 made of, for example, a tungsten material are disposed inside both ends of the hermetic container 11.

  The electrodes 14 and 15 are respectively taken out to the outside from the outer leads 20 and 21 electrically connected through the inner leads 18 and 19 partially sealed by the hermetic container 11 at the sealing portions 16 and 17, respectively. . The outer leads 20 and 21 are connected to a power source (not shown).

  Reference numerals 22 and 23 arranged in the vicinity of the electrodes 14 and 15 are electrodes, and the electrodes 22 and 23 are coated with an auxiliary emitter for starting discharge. As shown in FIG. 2, one end of the electrode 22 is taken out from the outer leads 24 and 25 through the inner lead 221 and the other end through the inner lead 222. The outer leads 24 and 25 are sealed together with the inner lead 18 at the sealing portion 16. The outer leads 24 and 25 are supplied with power (not shown) that excites the electrodes 22.

  Similarly, one end of the electrode 23 is taken out from the outer leads 26 and 27 through the inner lead 231 and the other end through the inner lead 232. The outer leads 26 and 27 are sealed together with the inner lead 19 at the sealing portion 17. The outer leads 26 and 27 are supplied with power (not shown) that excites the electrode 23.

  Reference numeral 28 denotes a capsule that is formed integrally with the distal end portion of the bent portion 12 and has a space portion 281 inside the length of about 30 mm that becomes the coldest portion. As shown in FIG. 3, the space portion 281 is a non-discharge space in which the inner diameter is about 5 mm and the discharge space 13 and the space portion 281 are connected by a connection hole 282 having an inner diameter of about 1 mm. Since the connecting hole 282 has a narrowed shape by the space portion 181, it is effective for holding the amalgam 30 when the light is extinguished.

  Reference numeral 29 denotes a connecting portion having increased mechanical strength by connecting both ends of the airtight container 11 at positions facing the bent portion 12 with the same material as the airtight container 11.

  The discharge space 13 is filled with 0.5 Torr of argon gas as an enclosed gas, and Sn (tin): 50 ± 5%, Bi (bismuth): 30 ± 5%, Pb (lead): 15 ± 5 as encapsulated chemicals. %, Hg (mercury): Amalgam 30 having a component ratio of 5% is enclosed. The amalgam 30 is also enclosed in the space 281 of the capsule 28.

  In addition, the relationship between the lamp current IL and the inner diameter φin of the hermetic container 11 is a high current density of IL / φin> 0.05. In the case of high current density, the temperature becomes high during lighting.

  When power is supplied to the low-pressure mercury discharge lamp configured as described above, electrons are first emitted from the electrodes 22 and 23, and the discharge in the discharge space 13 is destroyed and lighting is started. After lighting, the amalgam 30 is excited by receiving energy from electrons, and the amalgam 30 is emitted from the capsule 28 and emits 254 nm, which has a bactericidal effect based on the mercury contained in the amalgam 30.

  When the low-pressure mercury discharge lamp is turned off, the amalgam 30 is returned to the space 282 of the capsule 28 which is the coldest part. Thereafter, the same cycle is repeated at the time of lighting and at the time of lighting off.

  FIG. 4 explains the temperature dependence when a low-pressure mercury discharge lamp in which amalgam is contained in the capsule of the present invention and a low-pressure mercury discharge lamp in which conventional mercury is enclosed in a discharge space are lit under the same conditions. It is explanatory drawing for.

  That is, in the past, there is a location with high pinpoint luminous efficiency around 20 ° C. In the case of this invention, an amalgam comprising component ratios of Sn: 50 ± 5%, Bi: 30 ± 5%, Pb: 15 ± 5%, Hg: 5% in the capsule 28 which is the coldest part. The optimum temperature range when is enclosed is about 4 to 40 ° C. For this reason, it is possible to increase the luminous efficiency depending on the coldest part temperature in a wide temperature range.

  In this embodiment, the capsule which becomes the coldest part is formed at a position away from the electrode, and the amalgam exhibiting luminous efficiency in a wide temperature range is accommodated, so that a special gas temperature adjusting device is not required. High luminous efficiency can be realized.

  The present invention is not limited to the above-described embodiment. For example, the capsule 28 encapsulating the amalgam is formed in the middle part farthest from the electrodes 14 and 15, but is not limited to the middle part as long as the temperature is lower than that in the vicinity of the electrodes 14 and 15. Thereby, the capsule 28 is not limited to the downward direction, and may be formed in a horizontal direction, or may be formed obliquely or vertically depending on circumstances. In short, it may be the coldest part.

DESCRIPTION OF SYMBOLS 11 Airtight container 12 Bending part 13 Discharge space 14,15 Electrode 16,17 Sealing part 18,19,221,222,231,232 Inner lead 20,21,24,25,26,27 Outer lead 22,23 Electrode 28 Capsule 281 Space 282 Connection hole 29 Connection 30 Amalgam

Claims (4)

A rare gas is enclosed in the discharge space in the U-shaped hermetic vessel, and the lamp current IL and the inner diameter φin of the hermetic vessel have a relationship of IL / φin> 0.05, and at least the input power is 500 W. In low pressure mercury discharge lamps,
A low-pressure mercury discharge lamp comprising a capsule capable of communicating with the discharge space and capable of holding amalgam in a space portion that is the coldest portion of the hermetic vessel outside the discharge space.   2. The low-pressure mercury discharge lamp according to claim 1, wherein the capsule is formed at a position far from the both electrodes.   3. The low-pressure mercury discharge lamp according to claim 1, wherein the amalgam is composed of component ratios of Sn: 50 ± 5%, Bi: 30 ± 5%, Pb: 15 ± 5%, and Hg: 5%. .   The low-pressure mercury discharge lamp according to any one of claims 1 to 3, wherein a space portion of the capsule communicated with the discharge space is connected by a thin connection hole.

Images