JP2007311028A - Metal halide lamp lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal halide lamp lighting system of vertical lighting form capable of improving lamp efficiency even in the case of small added quantity of sodium. <P>SOLUTION: The metal halide lamp lighting system is provided with a metal halide lamp 5 which houses in an outer bulb 8 a ceramic arc tube 7 which has a pair of electrodes and into which a metal halide containing sodium is filled, a lighting device 20 which gives rectangular lamp current to the metal halide lamp and lights it, and a support equipment to support the metal halide lamp in vertical direction. This lighting device 20 lights the metal halide lamp 5 by superposing a direct current component on the rectangular lamp current so that DC bias may be impressed on the lower side electrode of the arc tube 7 of the metal halide lamp supported in vertical direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a metal halide lamp illumination device, and more particularly to a metal halide lamp illumination device suitable for a vertical lighting type.

  The metal halide lamp is a lamp in which a luminous metal is enclosed in the form of a halide in addition to mercury and a rare gas in an arc tube, thereby improving efficiency and color rendering. In order to improve the efficiency of this metal halide lamp, it is important to increase the vapor pressure of the metal halide which is a luminescent substance by increasing the temperature of the arc tube. For this reason, ceramic metal halide lamps using ceramics with high heat resistance have been used in recent years. In addition, sodium is widely used as one means for improving the efficiency of the lamp. However, the addition of sodium does not contribute to the efficiency improvement if the amount is small, and conversely, if the amount is large, the light color of the lamp is biased to yellow-orange and the correlated color temperature is low, so the efficiency is naturally improved. There was a limit.

In relation to the technology of the lamp lighting device, for example, Japanese Patent Application Laid-Open No. 2001-313190 discloses that the catalysis phenomenon of a discharge lamp is suppressed even in inverter lighting with a DC voltage superimposed. Japanese Patent Application Laid-Open No. 2006-049881 discloses that the direct current component of the high-frequency current that flows when the high-pressure discharge lamp starts is reduced. However, the above document does not disclose a technique related to sodium encapsulation in a metal halide lamp. Conventionally, when sodium is sealed in an arc tube made of quartz glass, in order to prevent the disappearance of sodium from the arc tube and reaction with quartz glass, a direct current voltage is not applied to the arc tube. Separating adjacent conductors with bimetal is also widely performed.
JP 2001-313190 A JP 2006-049181 A

  An object of the present invention is to provide a vertically lit type metal halide lamp illumination device capable of improving lamp efficiency even when the amount of sodium added is small.

  The object is to provide a metal halide lamp having a pair of electrodes and containing a ceramic arc tube enclosing a metal halide containing sodium in an outer bulb, and a lighting device for applying a rectangular wave lamp current to the metal halide lamp to light it. A metal halide lamp illuminating device comprising a support device for vertically supporting the metal halide lamp, wherein the lighting device applies a DC bias to a lower electrode of the arc tube of the metal halide lamp supported in the vertical direction. As described above, this is achieved by a metal halide lamp illuminating device that turns on the metal halide lamp by superimposing a DC component on the rectangular wave lamp current.

  Here, the direct current component is preferably 5% to 20% of the rectangular wave lamp current. The metal halide lamp may have a correlated color temperature of 4000K or higher. Furthermore, a switch capable of turning on and off the superimposition of the direct current component on the rectangular wave lamp current can be provided.

  In addition, the metal halide lamp lighting device according to the present invention is a device that has a pair of electrodes and is lit by applying a rectangular wave lamp current to a metal halide lamp in which a ceramic arc tube enclosing a metal halide containing sodium is housed in an outer bulb. The metal halide lamp is turned on by superimposing a DC component on the rectangular wave lamp current so that a DC bias is applied to one electrode of the arc tube. Here, the superimposition of the DC component on the rectangular wave lamp current can be turned on / off.

  According to the present invention, even when the amount of sodium added is small, sodium emission in the ceramic arc tube can be emitted across the arc tube electrodes, so that a vertically lit type metal halide lamp illumination device capable of improving lamp efficiency can be achieved. Can be obtained.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
1A and 1B are diagrams showing an embodiment of a vertically lit ceramic metal halide lamp lighting device according to the present invention, in which FIG. 1A is a circuit configuration diagram and FIG. 1B is an external view. As shown in the figure, this apparatus includes a rectifying / smoothing circuit 2 including a step-up chopper circuit connected to a commercial power supply 1 of 200 V and 50 Hz, and a rectangular wave ramp voltage (rectangular) of several hundred Hz by turning on and off four switching elements. Inverter circuit 3 for supplying the lamp current to the lamp 5 and the output of the inverter circuit 3 is detected by the output detection circuit 4 and the on / off of the switching element is controlled based on the detected DC output component of the inverter circuit 3 And a lighting device 20 having a control circuit 6 that controls the inverter circuit 3 so as to change the duty ratio of the rectangular wave lamp current to have a predetermined DC component. As will be described in detail later, the lamp 5 is a metal halide lamp having a pair of electrodes and a ceramic arc tube enclosing a metal halide containing sodium contained in an outer bulb. The lamp 5 is covered with, for example, a transparent cover 51 and is supported on the ceiling 53 in the vertical direction by the support device 52, and accordingly, the arc tube in the lamp is also supported in the vertical direction. In this case, the vertical direction is a concept including a substantially vertical direction.

  FIG. 2 is a diagram illustrating an example of the relationship between the rectangular wave lamp current and the DC component. In the figure, the horizontal axis represents time t, and the vertical axis represents the lamp current Ih. In this example, the upward portion (+ Ih) of the rectangular wave 21 is applied to the lower electrode of the arc tube supported in the vertical direction, and the downward portion (−Ih) is applied to the upper electrode. For example, the DC component when the duty ratio of the rectangular wave 21 is 50% is 0, and the DC component overlaps the horizontal axis. As shown in the figure, when the duty ratio of the rectangular wave 21 (the width of the upward portion in one period of the rectangular wave) is made larger than 50%, the DC component Id becomes as shown by the broken line 22 on the upper side of the horizontal axis and vice versa. In addition, when the duty ratio is smaller than 50%, the DC component is on the lower side of the horizontal axis.

  In the present embodiment, the lighting device 20 lights the lamp 5 by superimposing a DC component on the rectangular wave lamp current so that a DC bias is applied to the lower electrode of the arc tube of the lamp 5 supported in the vertical direction. Composed. That is, the direct current component has a relationship in which the lower electrode of the arc tube of the lamp 5 supported in the vertical direction is the positive electrode and the upper electrode is the negative electrode. The direct current component Id is preferably 5% to 20% of the rectangular wave lamp current Ih. This is because if the DC component is less than 5%, the effect of superimposing is small, and if the DC component is more than 20%, the luminous flux is reduced.

  The reason for configuring as described above is as follows. That is, when the amount of sodium added in the arc tube is small in the past, for example, when the amount added is 0.1 mg to 0.5 mg (when less than 0.1 mg, sodium enters the gap in the sealing portion and there is no amount added) The reason for not contributing to the improvement in efficiency is that sodium is polarized due to the synergistic effect of convection in the arc tube and ion diffusion, and the entire arc tube does not emit light. Therefore, the metal halide lamp is turned on by superimposing a DC component on the rectangular wave lamp current so that a DC bias is applied to the lower electrode of the arc tube of the metal halide lamp supported in the vertical direction. As a result, it is possible to reduce the difference between the vicinity of the upper electrode and the vicinity of the lower electrode of the ceramic arc tube with respect to the light emission of sodium at the time of lighting in the vertical direction, and it is possible to emit the sodium light between the arc tube electrodes. Sodium can emit light in the entire area of the arc tube that should emit light, and local sodium emission can be prevented, so that the efficiency is high and sufficient sodium emission can be achieved without excessive addition of sodium. Thus, the lamp efficiency can be improved while the color temperature is high. Regarding the color temperature, the lamp 5 can have a correlated color temperature of 4000 K or more.

  In addition, as shown in FIG. 1, the apparatus can include a switch 61 that controls the operation of the control circuit 6. Thus, for example, when the switch 61 is on, the duty ratio is changed as described above to obtain a rectangular wave lamp current having a predetermined direct current component, and when the switch 61 is off, the duty ratio is 50% and the direct current component is present. It can be a square wave lamp current that does not. As a result, not only the lighting in the vertical lighting type metal halide lamp but also the general type metal halide lamp other than the vertical lighting type can be turned on by switching off the circuit for superimposing the DC component.

  FIG. 3 is a diagram showing an example of a metal halide lamp used in the present invention. This figure shows the structure of a low voltage starting type ceramic metal halide lamp with a built-in starter. In the figure, a part of the low voltage starting type ceramic metal halide lamp is cut away so as to understand its internal structure.

  As shown in FIG. 3, for example, the ceramic arc tube 7 is hermetically sealed through a stem 11 inside an outer tube bulb 8 made of hard glass, and a lead wire 13a also serving as a support rod. , 13b. Therefore, when the metal halide lamp 5 is arranged in the vertical direction as shown in FIG. 3, the ceramic arc tube 7 is also arranged in the vertical direction, and the electrode 71 located on the side far from the base 14 becomes the upper electrode and is close to the base 14. The electrode 72 located on the side becomes the lower electrode. On the other hand, as shown in FIG. 1B, when the metal halide lamp 5 is disposed opposite to the vertical relationship in FIG. 3, the electrode 72 of the ceramic arc tube 7 becomes the upper electrode and the electrode 71 becomes the lower electrode. It becomes. A fluorescent film 9 is applied to the inner surface of the spherical portion of the outer tube bulb 8. The base 14 is mechanically caulked and fixed to the neck portion of the outer pipe valve 8, and is electrically connected to the lead wire.

  The reflection plate 10 is made of, for example, a white ceramic plate, and is disposed at a boundary portion between the spherical portion and the neck portion of the outer tube bulb, and is fixed by lead wires 13a and 13b that pass through holes provided in the reflection plate 9. Has been. Thereby, a spherical shape is formed by the spherical portion of the outer tube bulb and the reflecting plate 10. The proximity conductor 12 is made of a molybdenum wire having a thickness of 0.2 mm, and is provided in contact with the outer shape of the arc tube 1.

  Note that nitrogen gas is reduced to about one-half atmospheric pressure and enclosed in the outer tube valve 2. On the other hand, an appropriate amount of rare earth iodide such as argon gas of about 15 kPa as a starting gas, mercury of 40 mg as a buffer gas, sodium, thallium, and dysprosium as a luminescent metal is enclosed in the ceramic arc tube 1. . The distance between the electrodes is 22 mm.

  The performance obtained with the metal halide lamp 5 according to the present invention will be described below in comparison with the performance obtained with the conventional metal halide lamp.

  First, the metal halide lamp of this example was made with 1 mg of sodium iodide, the lamp of the conventional example was made with 3 mg of sodium iodide, and the others were manufactured and compared.

When the metal halide lamp of the present invention is incorporated in the lighting device of the present invention and turned on so that the direct current component of the lamp current is 0%, the duty ratio is 50%, and the lamp input power is 250 W. The luminous flux was 26500 lumens, the correlated color temperature was 5000K, and the average color rendering index was 85.
Next, when the metal halide lamp of the present invention was incorporated in the lighting device of the present invention and lit so that the direct current component of the lamp current was 5%, the luminous flux was 27250 lumens and the correlated color temperature was 4400 K with respect to the lamp input power of 250 W. The average color rendering index was 81.
Next, when the metal halide lamp of the present invention was incorporated in the lighting device of the present invention and lit so that the direct current component of the lamp current was 20%, the luminous flux was 27500 lumens and the correlated color temperature was 4200 K for a lamp input power of 250 W. The average color rendering index was 81.
Further, when the metal halide lamp of the present invention is incorporated in the lighting device of the present invention and is lit so that the direct current component of the lamp current is 30%, the lamp input power is 250 W, the luminous flux is 27000 lumens, the correlated color temperature is 4000 K, The average color rendering index was 80.

On the other hand, when a conventional metal halide lamp manufactured for comparison was incorporated into the lighting device of the present invention and turned on so that the direct current component of the lamp current was 0%, the luminous flux was 27000 lumens, the correlated color temperature was 3900 K, the average color rendering The evaluation number was 81.
In addition, when a conventional metal halide lamp manufactured for this comparison was incorporated in the lighting device of the present invention and turned on so that the direct current component of the lamp current was 5%, the luminous flux was 26750 lumen, the correlated color temperature was 3700 K, the average The color rendering index was 80.

  As can be seen from the above experimental results, when the DC component is not superimposed, the correlated color temperature of the metal halide lamp of the present invention is higher than that of the conventional metal halide lamp, although the luminous flux value is slightly lower. When the DC component is superimposed, both the correlated color temperature and the luminous flux are lower in the conventional metal halide lamp than in the case where the DC component is not superimposed, whereas in the metal halide lamp of the present invention, the luminous flux value is high. It has become. The correlated color temperature is also higher than that of the conventional metal halide lamp.

As can be seen from the above experimental results, the superimposition of the direct current component is preferably 5% or more and preferably 20% or less of the lamp current. If the direct current component is less than the above range, the superimposition effect does not appear or is small. .
In the vertical lighting type metal halide lamp illumination device according to the present invention, when the switch for superimposing the DC component on the lamp current is turned off, no problem occurs in lighting a general metal halide lamp.

  The present invention provides a metal halide lamp illuminating device that prevents the localization of sodium luminescence in a vertically lit ceramic metal halide lamp, has a high color temperature and is highly efficient, and has industrial applicability.

It is a figure which shows one Example of the vertical direction lighting type ceramic metal halide lamp illuminating device which concerns on this invention, (a) is a circuit block diagram, (b) is an external view. It is a figure which shows an example of the relationship between a rectangular wave lamp current and a direct-current component. It is a figure which shows an example of the metal halide lamp used for this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Power supply, 2 ... Rectification smoothing circuit, 3 ... Inverter circuit, 4 ... Output detection circuit, 5 ... Lamp, 6 ... Control circuit, 7 ... Ceramic arc tube, 8 ... Outer bulb, 9 ... Fluorescent film, 10 ... Reflection Plate, 11 ... Stem, 12 ... Proximity conductor, 13-a, 13-b ... Lead wire, 14 ... Base

Claims (6)

  A metal halide lamp having a pair of electrodes and containing a ceramic arc tube enclosing a metal halide containing sodium in an outer bulb, a lighting device for lighting the metal halide lamp by applying a rectangular wave lamp current, and the metal halide lamp A metal halide lamp illuminating device having a supporting device for supporting in the vertical direction, wherein the lighting device is configured to apply a DC bias to a lower electrode of the arc tube of the metal halide lamp supported in the vertical direction. A metal halide lamp illuminating device for lighting a metal halide lamp by superimposing a direct current component on a wave lamp current.   2. The metal halide lamp illumination device according to claim 1, wherein the direct current component is 5% to 20% of the rectangular wave lamp current.   The metal halide lamp illumination device according to claim 1, wherein the metal halide lamp has a correlated color temperature of 4000K or more.   The metal halide lamp illumination device according to claim 1, further comprising a switch capable of turning on and off the superimposition of the direct current component on the rectangular wave lamp current.   A metal halide lamp lighting device having a pair of electrodes and energizing a ceramic arc tube enclosing a metal halide containing sodium with a rectangular wave lamp current applied to a metal halide lamp accommodated in an outer bulb, wherein one of the arc tubes A metal halide lamp lighting device, wherein a direct current component is superimposed on the rectangular wave lamp current so that a direct current bias is applied to the electrode of the metal halide lamp, and the metal halide lamp is turned on.   6. The metal halide lamp lighting device according to claim 5, wherein the direct current component is superimposed on a rectangular wave lamp current on and off.

Images