JP2602647B2 - Metal vapor discharge lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a metal vapor discharge lamp having a built-in starting device.

(Prior Art) Since a high-pressure sodium lamp or a metal halide lamp has a high starting voltage, a means for superposing a power supply voltage pulse voltage at the time of starting is employed.

As a means for generating the pulse voltage, for example, a device in which a starting device including a lighting tube and a resistor for limiting a glow current of the lighting tube is built in the outer tube together with the arc tube is known. The above resistance was initially formed by filament,
Since the length is considerably long, it has to be formed in a coil shape and stretched in a zigzag shape, which is susceptible to vibrations and mechanical shocks, which causes a reduction in lamp reliability.
In order to cope with such a situation, the tungsten wire in the ceramic has excellent vibration resistance, can be compactly formed into a desired shape, and is suitable for installation in a narrow portion such as a discharge lamp. A means for replacing a ceramic resistor having such a resistor embedded therein is disclosed in Japanese Patent Application Laid-Open No. 56-73856. FIG. 3 shows a discharge lamp with a built-in starting device disclosed in this publication, where (1) is an outer tube, (4) is an arc tube, and (8)
A) is a disk-shaped ceramic resistor, (10) is an ignition tube,
(9) is a normally closed vital switch for disconnecting the starting circuit from the main lighting circuit after the discharge lamp is turned on. This vital switch (9) is connected in series with the ceramic resistor (8A) to form a unit. .

However, it has been found that such a discharge lamp has the following disadvantages. That is, in recent years, attention has been paid to the use of a metal vapor discharge lamp having a high efficiency in place of an incandescent lamp having a low efficiency. For this purpose, it is necessary to reduce the size of the metal vapor discharge lamp. In order to reduce the size of the discharge lamp, it is necessary to reduce the size of the outer tube. If the size of the outer tube is reduced, the outer tube neck for accommodating the starting device must necessarily be reduced. On the other hand, since the ceramic low antibody itself generates heat, it may be destroyed if it is attempted to reduce the size unnecessarily, and there is a limit to the size reduction.

For this reason, as in the case of the discharge lamp shown in FIG. 3, the outer tube neck (2) is arranged such that the plane portion of the disk-shaped ceramic resistor (8A) is perpendicular to the center axis of the outer tube (1). It was installed inside or on the upper end side. According to such a configuration, since the circular ceramic resistor also has an effect of shielding the radiant heat radiated from the arc tube (4) in the normal lighting state, it is located below the outer tube neck (2). There is an advantage that thermal deterioration of the lighting tube can be suppressed. However, with such a configuration, the size of the ceramic resistor is limited or the upper end of the outer tube neck (2) is covered. 2) The heat convection inside becomes worse, and the ceramic resistor (8A) becomes difficult to cool. As a result, the cooling rate of the bimetal switch (9), which is provided on the ceramic resistor (8A) and is open during lighting, is slowed down, and the return (close) time is prolonged. It has the disadvantage of being longer. This disadvantage is particularly noticeable when the lamp is turned on with the base (3) side up.

Japanese Patent Application Laid-Open No. 58-82453 discloses, as a description of the prior art, that a ceramic resistor is externally mounted so that a wide plane portion of a plate-shaped ceramic resistor is perpendicular to a center axis of an outer tube. A technique housed in a tube neck is disclosed.

In the technique disclosed in the publication, the upper end side of the outer tube neck portion is covered with a ceramic resistor, so the plane portion of the ceramic resistor is enlarged or the outer tube neck portion is narrowed, and the ceramic resistor is formed. When the gap between the outer tube and the outer tube is small, for example, when the light is turned off, the heat convection in the outer tube neck becomes worse, and the ceramic resistor becomes difficult to cool. As a result, the cooling rate of the bimetal switch, which is provided on the ceramic resistor and is open during lighting, is slowed down, resulting in a longer return (close) time, and thus a longer restart time. . This disadvantage is particularly noticeable when the lamp is lit with the base side up.

As described above, a structure in which the ceramic resistor is housed in the outer tube neck portion so that the wide flat portion of the plate-shaped ceramic resistor is perpendicular to the center axis of the outer tube is disclosed in Japanese Unexamined Patent Publication No.
No. 55-154053, JP-A-55-165566 and JP-A-55-165566
It is also described in JP-A-56-69761.

(Problems to be solved by the invention) In a discharge lamp having a conventional structure including a starting device including a bimetal switch, a ceramic resistor, and a lighting tube,
The outer tube neck is covered with a ceramic resistor. Therefore, especially when the size of the discharge lamp is reduced and the gap formed between the outer tube neck and the ceramic resistor is reduced, the atmosphere in the outer tube neck is easily stagnation, and it is difficult to cool down when the lamp is turned off. The return time of the set bimetal switch becomes long, and the restart cannot be performed satisfactorily. Further, if the outer tube neck is made small, the ceramic resistor is limited in shape and cannot be made to have a predetermined size.

Accordingly, an object of the present invention is to provide a metal vapor discharge lamp with a built-in starting device capable of performing a good restart even if the outer tube is downsized.

[Configuration of the invention]

(Means for Solving the Problems) In the metal vapor discharge lamp of the present invention, the arc tube housed in the outer tube and the plate-shaped, wide flat portion are parallel to the central axis of the outer tube. A ceramic resistor housed in the outer tube, a normally-closed bimetal switch arranged opposite one of the flat surfaces of the ceramic resistor in the outer tube, and a ceramic resistor so that the tube axis is parallel to the central axis of the outer tube. And a lighting tube disposed opposite to the other flat portion of the body.

(Operation) With such a configuration, the plate-shaped ceramic resistor is installed in parallel with the central axis of the outer tube, so that the outer tube neck is not covered with a lid. Even if the portion is small, the heat convection in the entire outer tube including the neck portion and the outer tube main body is improved. As a result, the ceramic resistor is easily cooled when the lamp is turned off, so that the bimetal switch provided on the flat surface side of the ceramic resistor can be normally restored, so that a good restart can be achieved. In addition, since the size (cross-sectional area) of the outer tube neck is limited and it is not necessary to forcibly reduce the size of the ceramic resistor, the ceramic resistor can be set to a predetermined size, thereby improving the restart. Can be. Furthermore, since the tube is arranged so that the tube axis of the tube is parallel to the central axis of the outer tube, heat radiation from the arc tube to the tube under normal lighting of the tube is reduced. Can be
Thermal deterioration of the lighting tube can be suppressed.

(Examples) Hereinafter, the present invention will be described in detail based on examples shown in the drawings.

FIG. 1 is a schematic structural explanatory view of a metal halide lamp which is one embodiment of a high-pressure metal vapor discharge lamp of the present invention.
(1) is an outer tube, the tip of the neck (2) is hermetically sealed, a base (3) is covered, and an arc tube (4) inside.
And a starting device (5). The arc tube (4) is formed by attaching a pair of electrodes (6A) and (6B) and enclosing a predetermined enclosure therein, and is supported by the outer tube (1) by the support frames (7A) and (7B). You. The starting device (5) is a rectangular plate-shaped ceramic resistor (8), a normally closed bimetal switch (9) provided on the resistor (8), and a lighting tube (10).
Are connected in series, and the starting device (5) is connected in parallel with the arc tube (4).

The rectangular plate-shaped ceramic resistor (8) is installed alongside the center axis of the outer tube (1), and the lighting tube (10) also has its center axis set at the center of the outer tube (1). The ceramic resistor (8) is arranged at a position facing the flat portion (8a) so as to be parallel to the axis.

FIG. 2 shows a lighting circuit diagram of the lamp. When the power supply is turned on, a current flows through a starting device (5) comprising a lighting tube (10), a ceramic resistor (8), and a normally closed bimetal switch (9). The operation of the lighting tube (10) induces an intermittent pulse voltage in the ballast (12), which is superimposed on the power supply voltage, and the two electrodes (6A) of the arc tube (4),
(6B) is applied to start the lamp.

When the lamp is turned on, the temperature inside the outer tube (1) rises, and the heat causes the bimetal switch (9) to open, thereby disconnecting the starting circuit from the lighting circuit.

With such a configuration, since the ceramic resistor (8) does not have a form in which the outer tube neck (2) is covered, the heat convection in the entire outer tube passes through the neck (2) and the main body. As a result, the ceramic resistor (8) is easily cooled when the lamp is turned off. In addition, since the bimetal switch (9) installed on the resistor (8) is cooled and closed early, the restart time can be reduced, and the size of the ceramic resistor (8) can be reduced. It can be designed to a desired size without being restricted by the cross-sectional area of the outer tube neck (2). Further, since the ceramic resistor (8) does not block light emitted from the arc tube (4) in the direction of the base (3), that is, in the direction of the neck (2), the efficiency can be improved. In addition, since the lighting tube (10) does not receive a large amount of heat during the sealing process of the outer tube (1) as in the related art, the damage can be avoided.

Furthermore, since the lighting tube (10) is disposed so that the tube axis of the lighting tube (10) is along the center axis of the outer tube (1), the tube axis of the lighting tube is centered on the outer tube. Radiation heat from the arc tube (4) to the lighting tube (10) can be reduced as compared with the case provided in the direction perpendicular to the axis. For this reason, there is an advantage that thermal deterioration of the lighting tube (10) over time due to radiant heat from the arc tube (4) can be reduced.

〔The invention's effect〕

According to the present invention, the plate-shaped ceramic resistor is installed in parallel with the central axis of the outer tube, and the lighting tube and the normally closed bimetal switch are installed at positions opposed to each other across the plane portion of the ceramic resistor. As a result, it is possible to suppress the thermal convection in the outer tube from being hindered by the ceramic resistor, and to perform the restart satisfactorily without being restricted by the size of the ceramic resistor. Furthermore, since the tube axis of the lighting tube is arranged along the central axis of the outer tube, the deterioration of the lighting tube with time due to radiant heat from the arc tube can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic structural explanatory view of an embodiment of a metal vapor discharge lamp of the present invention, FIG. 2 is a diagram showing a lighting circuit of the embodiment, FIG.
The figure is a schematic configuration explanatory view of a conventional lamp. (1) ... outer tube, (2) ... neck, (4) ... arc tube, (5) ... starting device, (8) ... ceramic resistor, (9) ... normally closed bimetal switch , (8a)… Planar part of ceramic resistor, (10)… Lighting tube.

Continued on the front page (72) Inventor Hisanori Sano 1-1201, Funakoshi-cho, Yokosuka City Inside Toshiba Yokosuka Plant, Inc. (72) Inventor Kazuo Takahashi 201-1, One, Funakoshi-cho, Yokosuka City Inside Yokosuka Plant, 56 References JP-A-58-82453 (JP, A) JP-A-56-73856 (JP, A) JP-A-55-154053 (JP, A) JP-A-55-165566 (JP, A) 56-69691 (JP, A)

Claims (1)

(57) [Claims] An outer tube; an arc tube housed in the outer tube; and a ceramic resistor housed in the outer tube formed in a plate shape such that a wide flat portion is parallel to a center axis of the outer tube. A normally-closed bimetal switch disposed opposite to one plane of the ceramic resistor in the outer tube; and disposed opposite the other plane of the ceramic resistor so that the tube axis is parallel to the center axis of the outer tube. And a lighting tube provided.