JPH062203Y2 - Small metal halide lamp - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a small metal halide lamp of 100 W (watt) or less.

[Technical background of the device and its problems]

Recently, from the viewpoint of power saving, technological development has been underway to replace a conventional incandescent light bulb with a metal halide lamp having excellent luminous efficiency, and for example, Japanese Patent Laid-Open No. 54-63567 discloses such a technology. A compact metal halide lamp of 100 W or less of interest is shown. When such a small metal halide lamp is used outdoors, there are also restrictions on the lighting equipment that houses the lamp due to problems such as ceiling height and space behind the ceiling. By doing so, it is considered that the lighting equipment is downsized or the light distribution is improved. However, when a metal halide lamp is lit horizontally, the arc bends upward and approaches or contacts the upper tube wall of the arc tube abnormally, which causes a decrease in lamp efficiency and color rendering, as well as the lamp voltage during lighting. However, there are drawbacks such as the disappearance and the shortening of the life due to the sudden rise of.

To deal with this, for example, in JP-A-54-150870, the electrodes are tilted and sealed, and the tip positions of the electrodes are unevenly distributed below the central axis of the arc tube so that the arc bends upward during lighting. However, the means for making the arc center line coincide with the arc tube center axis is shown. However, such means also have various problems in the case where the input of the arc tube is small, for example, in a small metal halide lamp having an arc tube inner volume of 1 cc or less at 100 W or less. This situation will be described with reference to FIG. Fig. 1 shows a 40W small metal halide lamp arc tube, and the sealing parts (1
a), (1a) electrodes (2), (2) seal the base (2a), (2a), external lead wire (4), via molybdenum foil (3), (3), (Four)
Respectively connected to.

The electrodes (2) and (2) are inclined and sealed, and the respective tip portions (2b) and (2b) are unevenly distributed below the arc tube central axis (A). Such an arc tube (1) has a volume of 1 cc or less and is extremely small compared to the arc tubes of conventional medium to high wattage lamps, so naturally the light emitting section and sealing parts (1a), (1a) are also small. Therefore, it is difficult to accurately control the inclination angle of the electrodes (2) and (2) in terms of manufacturing, and it is difficult to accurately obtain a predetermined inter-electrode distance and electrode position. Moreover, since the electrode (2) is inclined in the sealing portion (1a) and is biasedly sealed, the sealing width on both sides of the electrode (2) becomes uneven, or the electrode base (2a) ), (2a) and molybdenum foils (3), (3) are not joined well, and this part is unreasonable, which causes cracks in the sealing parts (1a), (1a) during sealing. Raised or molybdenum foil
(3) and (3) have the drawback that foil breakage occurs and the temperature distribution during lighting differs among lamps, making it difficult to obtain a lamp having uniform characteristics.

[Purpose of device]

The present invention has been made in consideration of the above circumstances, and it is possible to reduce the deviation of the arc center line from the arc tube center line during horizontal lighting and prevent the occurrence of damage to the arc tube sealing portion.
Further, it is an object of the present invention to provide a small metal halide lamp having improved characteristics and stable characteristics by maintaining a predetermined distance between electrodes and electrode positions accurately.

[Outline of device]

The present invention is a small metal halide lamp of 100 W or less which is used for lighting in a horizontal position. The arc tube is provided with a sealing part having electrodes sealed at both ends of the arc tube so as to be inclined upward from the central axis of the arc tube. Further, the tip ends of both electrodes sealed along the central axis of the sealing portion are located below the central axis of the arc tube.

[Example of device]

Hereinafter, the details of the present invention will be described with reference to the illustrated embodiment. FIG. 2 is a drawing showing an arc tube of a 40 W small metal halide lamp, in which (a) is a front view and (b) is a plan view. In the figure, (1) is an arc tube made of quartz glass and having a maximum inner diameter of about 8 mm and formed into a substantially spherical shape. At both ends of the arc tube, electrodes (2) and (2) are sealed, respectively. , (1a) its central axis (B), (B) with respect to the central axis (A) of the arc tube (1),
It is provided so as to be inclined upward and unevenly distributed in a state where the arc tube is lit. Further, the electrodes (2) and (2) are such that the distal end portions (2b) and (2b) of the central axis (A) of the arc tube are eccentrically distributed downward in the lighting state of the arc tube, and the base end portion ( 2
Connect a) and (2a) to one end of molybdenum foil (3) and (3), and connect one end of external lead wires (4) and (4) to the other end of molybdenum foil (3) and (3). The linear connecting body consisting of the electrode base end (2a), molybdenum foil (3) and one end of the external lead wire (4) is connected along the central axis (B) of the sealing part (1a). It has been sealed. Further, for example, 100 torr of argon gas, 10 mg of mercury, 2 mg of scandium iodide and sodium iodide as metal halides in total, and further 0.05 mg of scandium metal are enclosed in the arc tube (1). Note that (5) is the tip portion of the exhaust pipe. Although not shown, such an arc tube is usually sealed in an outer tube having a base attached to one end to complete a lamp.

Next, the following table shows the results of the characteristic comparison test between the conventional lamp shown in FIG.

The number of tests is 30 for each, and the common target value is the target setting value of the electrode distance is 4mm ± 0.05mm, lamp voltage 85V ± 5V,
The initial light flux is 3,200n, the color temperature is 3200K to 3500K, there is no crack in the sealing part, there is no foil breakage of the molybdenum foil, etc. .

As is clear from the table, the effect of the present invention is remarkable. The reason for this is that in the conventional lamp, only the electrode (2) was tilted, whereas the lamp of the present invention, together with the electrode (2), has the sealing part (1a)
Since it is also formed so as to be tilted upward and unevenly distributed with respect to the central axis of the arc tube (A) when the arc tube is lit,
The width of the sealing parts on both sides centering on the electrode base (2a) is uniform and cracks are less likely to occur, and the electrode base (2a), molybdenum foil (3) and external lead wire (4) are linear and Sealing part (1
Since it is provided along the central axis (B) of a), foil breakage or the like does not occur. Moreover, since the electrode (2) is not forcibly inclined with respect to the sealing portion (1a), the electrode tip portion (2b) is unevenly distributed below the arc tube central axis (A), and both tip portions ( Since it is easy to keep the distance between 2a) and (2a) at a predetermined interval,
It is also easy to set various optical characteristics in desired ranges.

FIG. 3 shows another embodiment, FIG. 3 (a) is a front view, and FIG. 3 (b) is a plan view thereof. The same parts as those of the previous embodiment shown in FIG. Omit it. In this embodiment, the angle of the crushing surface of the sealing parts (1a) and (1a) in the previous example is changed by 90 °, and the angle of uneven distribution of the sealing part with respect to the arc tube central axis (A) is It is similar to the embodiment of. In this case, the same effect was obtained.

Although each of the above embodiments relates to a 40 W lamp, the present invention has the same effect in other small metal halide lamps of 100 W or less.

[Effect of device]

As described above in detail, according to the present invention, the position of the electrode of the small metal halide lamp of 100 W or less used for horizontal lighting is located below the central axis of the arc tube so that the arc position substantially coincides with the central axis of the arc tube. In addition, since the sealing portion itself is provided with the electrodes in a biased manner (inclined) with respect to the arc tube, a predetermined design is facilitated, and the sealing portion is not damaged, and a lamp having improved characteristics is obtained. Made it possible.

[Brief description of drawings]

FIG. 1 is a front view of an arc tube of a conventional lamp, FIG. 2 is a front view of an arc tube of an embodiment of the present invention, a is a front view thereof, and FIG. 3 is a view of an arc tube of another embodiment. a is a front view and b is a top view, respectively. (1) …… Arc tube, (1a) …… Sealing part (2) …… Electrode, (3) …… Molybdenum foil

Claims (1)

[Scope of utility model registration request] 1. A sealing part having electrodes sealed at both ends of the arc tube is provided so as to be eccentrically inclined above a central axis of the arc tube and is sealed along the central axis of the sealing part. A small metal halide lamp for horizontal lighting of 100 W or less, characterized in that the tips of both electrodes are positioned below the central axis of the arc tube.