JP2009076396A - Metal halide lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal halide lamp in which arc flickering is hardly generated. <P>SOLUTION: In the metal halide lamp 1 in which rare gas, mercury, and thallium iodide are filled as discharge medium in an airtight arc tube and discharge electrodes 3, 4 are installed at both ends in tube axial direction of the arc tube, when the inner diameter of the arc tube is denoted as D and the gas pressure of the filled gas is denoted as P, the value of P×D (mm×torr) is 75<P×D<2,125. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a metal halide lamp.

  A metal halide lamp in which a rare gas, mercury and thallium iodide are sealed as a discharge medium in an airtight arc tube and discharge electrodes are installed at both ends in the tube axis direction of the arc tube, emits ultraviolet light with high emission intensity around 365 nm. Therefore, it is useful as a light source used for curing UV curable coatings and for photoreactions on functional polymer films that have recently been used in high market applications.

  However, such a metal halide lamp has a problem in that light emission from mercury and thallium iodide is separated during lighting, and arc fluctuation is likely to occur depending on the lamp length.

  This arc swing is a phenomenon in which the arc during discharge does not become straight but swells with respect to the lamp axis direction. When this arc sway occurs, the lamp voltage fluctuates, and the arc tube bulges due to a rise in arc tube temperature.

Acoustic resonance is known as a cause of arc fluctuation. In the lamp, the input is periodically increased or decreased depending on the frequency of the power supply voltage, and a rough wave (dense when the input increases, coarse when the input decreases) is generated by plasma (mercury vapor) from the arc toward the lamp tube wall. At the same time, a reflected wave that is reflected by the tube wall and returned to the lamp tube wall is generated. When these two waves interfere with each other, a standing wave whose pressure distribution does not change with time is generated. When such a standing wave is generated, non-uniform pressure in the lamp tube makes the arc state unstable and causes arc fluctuation (bending).
Japanese Patent Laid-Open No. 06-275234

  The present invention has been made in view of the above technical problem, and an object of the present invention is to provide a metal halide lamp in which arc fluctuation is unlikely to occur.

  The present invention provides a metal halide lamp in which a rare gas, mercury, and thallium iodide are sealed as a discharge medium in an airtight arc tube, and discharge electrodes are installed at both ends in the tube axis direction of the arc tube. When the gas pressure P of the sealed gas is set, the value of P × D (mm × torr) is set to 75 <P × D <2125.

  According to the metal halide lamp of the present invention, the relationship P × D (mm × torr) between the inner diameter D of the arc tube and the gas pressure P of the sealed gas is set to 75 <P × D <2125. There is no decrease in reliability, the diffusion of mercury and thallium iodide is facilitated, and the light emission of the lamp can be maintained stably.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a metal halide lamp 1 according to an embodiment of the present invention. The metal halide lamp 1 includes electrodes 3 and 4 made of a refractory metal such as tungsten, nickel, molybdenum, and tantalum, or a metal such as stainless steel and titanium, at both ends of a quartz arc tube 2 having ultraviolet transparency. And the sockets 5 and 6 are provided outside.

  An example of the specification of the metal halide lamp 1 is that the lamp emission length is 1000 mm, the applied lamp voltage is 1275 V, and the lamp current value is 13.5 A. The amount of thallium iodide enclosed is 0.032 mg / cc and mercury is 1.68 mg / cc. The gas pressure P (torr) of the rare gas is 75 <P × D <2125 (75 × 133.320 <P × D <2125 × in terms of Pascal) in relation to the inner diameter D (mm) of the arc tube 2. 133.320) is only enclosed. For example, when the inner diameter D = 15 mm, the rare gas sealing pressure P = 5 torr (about 667 Pa) or higher, and even when the inner diameter D = 35 mm, the rare gas sealing pressure P = 60 torr (about 8000 Pa) or lower is preferable. . Further, when the inner diameter D = 25 mm, it is preferable that the rare gas sealing pressure P = 10 torr (about 1332 Pa).

  When the amount of rare gas sealed is small, blackening of mercury occurs remarkably and reliability is lowered. However, by setting P × D to 75 or more, the rare gas can be sealed to the extent that blackening does not affect it. The reliability in this point can be maintained. Further, diffusion of mercury and thallium iodide is facilitated, and arc emission does not occur, and the light emission of the lamp can be stably maintained. On the other hand, if the amount of rare gas filled is increased so that P × D exceeds 2125, the start-up / restart characteristics of the lamp are deteriorated, and separated light emission appears remarkably. Therefore, by adjusting the amount of rare gas filled so that the gas pressure P and the lamp tube diameter D are in the range of 75 <P × D <2125, there is no decrease in reliability due to blackening, and separation light emission No metal halide lamp with excellent start / restart characteristics can be obtained.

The experimental results when determining the optimal range of P × D are shown below.
[Example 1]

実施例１では、上表の通り、ランプ長８５０ｍｍ、ランプ内径２５ｍｍのメタルハライドランプに対して、アルゴンガスを２．５ｔｏｒｒ（約３３３Ｐａ）、５ｔｏｒｒ（約６６７Ｐａ）、１０ｔｏｒｒ（約１３３３Ｐａ）、３０ｔｏｒｒ（約４０００Ｐａ）、４０ｔｏｒｒ（約５３２８Ｐａ）、６０ｔｏｒｒ（約８０００Ｐａ）、８０ｔｏｒｒ（約１０６５６Ｐａ）、９０ｔｏｒｒ（約１１９８８Ｐａ）それぞれのガス圧になるように封入し、発光試験を行った。

In Example 1, as shown in the above table, argon gas is 2.5 torr (about 333 Pa), 5 torr (about 667 Pa), 10 torr (about 1333 Pa), 30 torr (about about 850 mm and a metal halide lamp having a lamp inner diameter of 25 mm. 4000 Pa), 40 torr (about 5328 Pa), 60 torr (about 8000 Pa), 80 torr (about 10656 Pa), and 90 torr (about 11988 Pa) were sealed at respective gas pressures, and a light emission test was performed.

  As a result, in the case of a metal halide lamp with P × D (mm × torr) of 62.5, blackening was noticeable and it was determined that the reliability was low. Further, in the case of a metal halide lamp with P × D (mm × torr) of 2250, no blackening was observed, but separate light emission occurred, and the starting / restarting operation characteristics deteriorated. Was judged as bad overall.

On the other hand, in the case of each metal halide lamp having P × D (mm × torr) of 125 to 2000, there is no separate emission, good start / restart operation characteristics, and good black characteristics without blackening. It was confirmed that
[Example 2]

実施例２では、上表の通り、ランプ長１０００ｍｍ、ランプ内径２５ｍｍのメタルハライドランプに対して、アルゴンガスを２．５ｔｏｒｒ（約３３３Ｐａ）、５ｔｏｒｒ（約６６７Ｐａ）、１０ｔｏｒｒ（約１３３３Ｐａ）、３０ｔｏｒｒ（約４０００Ｐａ）、４０ｔｏｒｒ（約５３２８Ｐａ）、６０ｔｏｒｒ（約８０００Ｐａ）、８０ｔｏｒｒ（約１０６５６Ｐａ）、９０ｔｏｒｒ（約１１９８８Ｐａ）それぞれのガス圧になるように封入し、発光試験を行った。

In Example 2, as shown in the above table, argon gas was supplied at 2.5 torr (about 333 Pa), 5 torr (about 667 Pa), 10 torr (about 1333 Pa), 30 torr (about 1 to 30 mm) with respect to a metal halide lamp having a lamp length of 1000 mm and a lamp inner diameter of 25 mm. 4000 Pa), 40 torr (about 5328 Pa), 60 torr (about 8000 Pa), 80 torr (about 10656 Pa), and 90 torr (about 11988 Pa) were sealed at respective gas pressures, and a light emission test was performed.

  As a result, in the case of a metal halide lamp with P × D (mm × torr) of 62.5, blackening was noticeable and it was determined that the reliability was low. Further, in the case of a metal halide lamp with P × D (mm × torr) of 2250, no blackening was observed, but separate light emission occurred, and the start / restart operating characteristics were significantly deteriorated, resulting in lamp characteristics. Was judged as bad overall.

On the other hand, in the case of each metal halide lamp with P × D (mm × torr) of 125 to 1500, there is no separate emission, good start / restart operation characteristics, and good black characteristics without blackening. It was confirmed that In addition, in the case of a metal halide lamp having a P × D (mm × torr) of 2000, a slight decrease was observed in the start / restart characteristics, but no separate light emission occurred and no blackening was observed. Therefore, the lamp characteristics were judged as good overall.
Example 3

実施例３では、上表の通り、ランプ長１０００ｍｍ、ランプ内径２５ｍｍのメタルハライドランプに対して、キセノンガスを２．５ｔｏｒｒ（約３３３Ｐａ）、５ｔｏｒｒ（約６６７Ｐａ）、１０ｔｏｒｒ（約１３３３Ｐａ）、３０ｔｏｒｒ（約４０００Ｐａ）、４０ｔｏｒｒ（約５３２８Ｐａ）、６０ｔｏｒｒ（約８０００Ｐａ）、８０ｔｏｒｒ（約１０６５６Ｐａ）、９０ｔｏｒｒ（約１１９８８Ｐａ）それぞれのガス圧になるように封入し、発光試験を行った。

In Example 3, as shown in the above table, xenon gas is 2.5 torr (about 333 Pa), 5 torr (about 667 Pa), 10 torr (about 1333 Pa), 30 torr (about 1 to 30 mm) with respect to a metal halide lamp having a lamp length of 1000 mm and a lamp inner diameter of 25 mm. 4000 Pa), 40 torr (about 5328 Pa), 60 torr (about 8000 Pa), 80 torr (about 10656 Pa), and 90 torr (about 11988 Pa) were sealed at respective gas pressures, and a light emission test was performed.

  As a result, in the case of a metal halide lamp with P × D (mm × torr) of 62.5, blackening was noticeable and it was determined that the reliability was low. Further, in the case of a metal halide lamp with P × D (mm × torr) of 2250, no blackening was observed, but separate light emission occurred, and the start / restart operating characteristics were significantly deteriorated, resulting in lamp characteristics. Was judged as bad overall.

On the other hand, in the case of each metal halide lamp with P × D (mm × torr) of 125 to 1500, there is no separate emission, good start / restart operation characteristics, and good black characteristics without blackening. It was confirmed that In addition, in the case of a metal halide lamp having a P × D (mm × torr) of 2000, a slight decrease was observed in the start / restart characteristics, but no separate light emission occurred and no blackening was observed. Therefore, the lamp characteristics were judged as good overall.
Example 4

実施例４では、上表の通り、ランプ長１８００ｍｍ、ランプ内径２５ｍｍのメタルハライドランプに対して、アルゴンガスを２．５ｔｏｒｒ（約３３３Ｐａ）、５ｔｏｒｒ（約６６７Ｐａ）、１０ｔｏｒｒ（約１３３３Ｐａ）、３０ｔｏｒｒ（約４０００Ｐａ）、４０ｔｏｒｒ（約５３２８Ｐａ）、７５ｔｏｒｒ（約１００００Ｐａ）、８５ｔｏｒｒ（約１１３３２Ｐａ）、９０ｔｏｒｒ（約１１９８８Ｐａ）それぞれのガス圧になるように封入し、発光試験を行った。

In Example 4, as shown in the above table, argon gas is 2.5 torr (about 333 Pa), 5 torr (about 667 Pa), 10 torr (about 1333 Pa), 30 torr (about 1800 mm) with respect to a metal halide lamp having a lamp length of 1800 mm and a lamp inner diameter of 25 mm. 4000 Pa), 40 torr (about 5328 Pa), 75 torr (about 10,000 Pa), 85 torr (about 11332 Pa), and 90 torr (about 11988 Pa) were sealed at respective gas pressures, and a light emission test was performed.

  As a result, in the case of a metal halide lamp with P × D (mm × torr) of 62.5, blackening was noticeable and it was determined that the reliability was low. Further, in the case of a metal halide lamp with P × D (mm × torr) of 2250, no blackening was observed, but separate light emission occurred, and the start / restart operating characteristics were significantly deteriorated, resulting in lamp characteristics. Was judged as bad overall.

On the other hand, in the case of each metal halide lamp having P × D (mm × torr) of 125 to 1875, there is no separate emission, good start / restart operation characteristics, and good black characteristics without blackening. It was confirmed that In addition, in the case of a metal halide lamp with P × D (mm × torr) of 2125, a slight decrease in the start / restart characteristics was observed, but no separate light emission occurred and no blackening was observed. Therefore, the lamp characteristics were judged as good overall.
Example 5

実施例５では、上表の通り、ランプ長２０００ｍｍ、ランプ内径２５ｍｍのメタルハライドランプに対して、アルゴンガスを２．５ｔｏｒｒ（約３３３Ｐａ）、５ｔｏｒｒ（約６６７Ｐａ）、１０ｔｏｒｒ（約１３３３Ｐａ）、３０ｔｏｒｒ（約４０００Ｐａ）、４０ｔｏｒｒ（約５３２８Ｐａ）、７５ｔｏｒｒ（約１００００Ｐａ）、８５ｔｏｒｒ（約１１３３２Ｐａ）、９０ｔｏｒｒ（約１１９８８Ｐａ）それぞれのガス圧になるように封入し、発光試験を行った。

In Example 5, as shown in the above table, argon gas was supplied at 2.5 torr (about 333 Pa), 5 torr (about 667 Pa), 10 torr (about 1333 Pa), 30 torr (about 1 to 30 mm) with respect to a metal halide lamp having a lamp length of 2000 mm and an inner diameter of 25 mm. 4000 Pa), 40 torr (about 5328 Pa), 75 torr (about 10,000 Pa), 85 torr (about 11332 Pa), and 90 torr (about 11988 Pa) were sealed at respective gas pressures, and a light emission test was performed.

  As a result, in the case of a metal halide lamp with P × D (mm × torr) of 62.5, blackening was noticeable and it was determined that the reliability was low. Further, in the case of a metal halide lamp with P × D (mm × torr) of 2250, no blackening was observed, but separate light emission occurred, and the start / restart operating characteristics were significantly deteriorated, resulting in lamp characteristics. Was judged as bad overall.

  On the other hand, in the case of each metal halide lamp having P × D (mm × torr) of 125 to 1875, there is no separate emission, good start / restart operation characteristics, and good black characteristics without blackening. It was confirmed that In addition, in the case of a metal halide lamp with P × D (mm × torr) of 2125, a slight decrease in the start / restart characteristics was observed, but no separate light emission occurred and no blackening was observed. Therefore, the lamp characteristics were judged as good overall.

The front view of the metal halide lamp of one embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Metal halide lamp 2 ... Arc tube 3, 4 ... Electrode 5, 6 ... Socket

Claims (1)

In a metal halide lamp in which rare gas, mercury and thallium iodide are sealed as a discharge medium in an airtight arc tube, and discharge electrodes are installed at both ends in the tube axis direction of the arc tube,
A metal halide lamp, wherein a value of P × D (mm × torr) is set to 75 <P × D <2125 when the inner diameter D of the arc tube and the gas pressure P of the sealed gas are set.

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