JP3275768B2 - High pressure metal vapor discharge lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-pressure metal vapor discharge lamp having an arc tube made of a translucent ceramic.

[0002]

2. Description of the Related Art As a conventional high-pressure metal vapor discharge lamp having an arc tube made of ceramic, a lamp using an arc tube in which both ends of a cylindrical portion are shrink-fitted with disks is known (Japanese Patent Laid-Open No. 6-196131). No.).

In such a conventional high-pressure metal vapor discharge lamp, even when the lighting direction changes, that is, when the lighting is performed in a vertical direction or the electrodes are arranged horizontally and the lighting is performed horizontally, the condensed phase of the excess luminescent metal compound is burned. As a result, characteristics that are present in the closed portion and do not depend on the lighting direction can be obtained. However, such shrink-fitting closures have a problem in reliability with respect to airtightness, and the characteristics are not sufficiently ensured during the life.

[0004]

On the other hand, in an arc tube having a cylindrical portion and a tapered portion, and a tapered portion connected to both ends of the cylindrical portion, the cylindrical portion and the tapered portion are connected to each other. Therefore, there is no need to block by shrink fitting, and reliability for airtightness can be ensured. However, depending on the lighting direction, the position of the condensed phase of the surplus luminescent metal compound changes,
There was concern that the characteristics would fluctuate.

An arc tube having a cylindrical portion and a tapered portion, and having a tapered portion connected to both ends of the cylindrical portion, is a shape usually employed in an arc tube using a quartz material. There are many disclosed examples of the arc tube used. However, compared to quartz, ceramic materials have different properties such as heat conduction and heat radiation, and it is not possible to control the coldest point in the arc tube by the shape of the sealing part or the heat insulation film. The method of preventing the characteristic change when the lighting direction changes due to the shape of the device cannot be applied, and a new study for suppressing the characteristic change when the lighting direction changes is needed.

An object of the present invention is to provide a high-pressure metal vapor discharge lamp in which a characteristic of an arc tube having a tapered portion has little change with respect to a change in a lighting direction. With the goal.

[0007]

A high-pressure metal vapor discharge lamp according to the present invention has a pair of electrodes, at least mercury, a rare gas, and a luminescent metal compound sealed therein, and a first cylindrical portion and a first cylindrical portion. A tapered portion connected to both ends, a second tubular portion smaller than the inner diameter of the first tubular portion at one end of each of the tapered portions, and a pair of the electrodes are located inside It said electrode comprising an arc tube made of ceramic which is fixed and held to the second cylindrical portion so as, with the tapered portion in the surface of the arc tube, the angle α is 50 degrees to the axis of the electrode
80 degrees, and the ratio of the length L (mm) of the first cylindrical portion to the inner diameter D (mm) of the first cylindrical portion is -0.014α +
It has a configuration in which 1.4 ≦ (D / L) ≦ 0.017α + 0.36.

As a result, it has high efficiency and high color rendering properties,
A high-pressure metal vapor discharge lamp having excellent life characteristics without any limitation on the lighting direction can be obtained.

[0009]

Embodiments of the present invention will be described below.

As shown in FIGS. 1 and 2, a high-pressure metal vapor discharge lamp according to an embodiment of the present invention has an arc tube 1 made of ceramic in an outer tube 9, and the arc tube 1 has an inner diameter. D has a first cylindrical portion 11 having a length of 10.6 mm and a length L of 10.8 mm, second cylindrical portions 17a and 17b, and a tapered portion 12. Tapered portions are provided at both ends of the first cylindrical portion 11. 1
2 are connected to each other.
The other ends of the second cylindrical portions 17a and 17b smaller than the inner diameter of the first cylindrical portion 11 are connected to each other.

Electrode shafts 14a, 14b made of tungsten wires having electrode coils 13a, 13b at one end are connected to sealing bodies 15a, 15b made of alumina containing tungsten.
It is airtightly integrated with shrink fit. The sealing bodies 15a, 15b having the electrode shafts 14a, 14b are inserted into the second cylindrical portions 17a, 17b so that the electrode coils 13a, 13b are located in the first cylindrical portion 11, and the frit 16
Is hermetically sealed. At this time, there is an angle α between the inner surface of the tapered portion 12 of the arc tube 1 and the electrode shafts 14a and 14b. In the case of the present embodiment, the angle α is 64 degrees.

In this embodiment, the electrode shafts 14a and 14b penetrate the sealing bodies 15a and 15b, and the portions of the electrode shafts 14a and 14b derived from the arc tube 1
a, 4b also play a role. Further, mercury, a rare gas, and a luminescent metal compound are sealed inside the arc tube 1.

The luminous tube 1 is surrounded by a light-transmitting tube 2 having openings at both ends, and further provided inside the light-transmitting tube 2 with openings at both ends closed by metal plates 3a and 3b. Current supply lines 4a derived from both ends of the arc tube 1
4b penetrates the metal plates 3a and 3b.

One end of the outer tube 9 is closed, and the other end is provided with a stem 5 sealed. An electrode shaft 14a, that is, the other end of the current supply line 4a is connected to the support wire 6a derived from the stem 5, and one end of the support wire 8 is connected to the support wire 6b derived from the stem 5, An electrode shaft 14 is attached to the other end of the support wire 8.
b, that is, the other end of the current supply line 4b is connected. As described above, the arc tube 1 holds the current supply lines 4a and 4b derived from the arc tube 1 by being connected to the support wires 6a or the support wires 8, respectively.

The current supply lines 4a, 4b and the metal plates 3a, 3b are insulated by an insulating sleeve 7. Also, the base 10 is covered so as to cover the sealing portion between the stem 5 and the outer tube 9.
Is attached. Further, nitrogen gas is sealed in the outer tube 9.

In the arc tube 1, the electrode shafts 14a,
The angle α between the central axis of the base 14b and the slope of the tapered portion 12 inside the arc tube 1 is 45 to 80 degrees, and the inner diameter D (mm) relative to the length L (mm) of the first cylindrical portion 11, that is, D /
The initial characteristics with respect to the lighting direction variation when L was changed from 0.4 to 1.5 were examined. As a characteristic with respect to the lighting direction variation, a difference in correlated color temperature between vertical lighting and horizontal lighting at a lamp power of 150 W was used. The result is shown in FIG.

At this time, the electrode coils 13a, 13b
Is a 0.25 mm tungsten wire wound five turns, the electrode shafts 14a and 14b are 0.5 mm tungsten rods, and the inner diameter d of the second cylindrical portions 17a and 17b is 2.0 m.
m. The encapsulating metal compound was dysprosium iodide, thallium iodide, sodium iodide, and lithium iodide at a composition ratio of 22: 19: 55: 4, respectively, 5.0.
mg, 16 KPa of argon gas, and a lamp voltage of 9
An appropriate amount of mercury is sealed so as to be 3V.

As is apparent from FIG. 3, the change in the color temperature characteristic due to the change in the lighting direction is reduced by increasing the angle α, and there is a margin for suppressing the difference in the correlated color temperature to a change amount of 300 K or less. In consideration of this, the angle α needs to be 50 degrees or more. Also, it can be seen that the color temperature change amount decreases as D / L approaches 1.

FIG. 4 shows a straight line A and a straight line B for the value of D / L with respect to the angle α when the amount of change becomes 300K. As is clear from FIG. 4, in order to make the variation of the correlated color temperature between vertical lighting and horizontal lighting less than 300 K, as shown in FIG. Angle α
And D / L. The angle α between the tapered portion 12 and the electrode shafts 14a and 14b is preferably up to 80 degrees from the manufacturing surface of the tapered portion 12. When the angle is set to 80 degrees or more, the inner angle between the first cylindrical portion 11 and the tapered portion 12 becomes small, and a thin portion is locally formed in the blow molding. As a result, the strength is weakened, and cracks occur during lighting. The arc tube is preferably formed by blowing from the viewpoint of cost.

In the present embodiment, the electrode shafts 14a, 1
Although 4b has penetrated the sealing bodies 15a and 15b, it may be configured to use a conductive cermet and not penetrate. At least one of the sealing bodies 15a and 15b may be sealed by shrink fitting instead of frit.

[0021]

As described above, according to the present invention, it is possible to obtain a high-pressure metal vapor discharge lamp having a high efficiency and a high color rendering with little change in characteristics even if the lighting direction changes.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional front view of a high-pressure metal vapor discharge lamp according to an embodiment of the present invention.

FIG. 2 is a sectional view of the arc tube.

FIG. 3 is a diagram for explaining that a change in characteristics due to a change in a lighting direction depends on the shape of an arc tube;

FIG. 4 is a view for explaining conditions of a shape of an arc tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Arc tube 11 1st cylindrical part 12 Taper part 13a, 13b Electrode coil 14a, 14b Electrode shaft 15a, 15b Sealing body 17a, 17b 2nd cylindrical part

──────────────────────────────────────────────────続 き Continuing from the front page (72) Yoshiharu Nishiura, Inventor 1-1, Yukicho, Takatsuki-shi, Osaka Prefecture Inside Matsushita Electronics Corporation (72) Inventor Kazuo Takeda 1-1, Yukicho, Takatsuki-shi, Osaka Matsushita Electronics Within Kogyo Co., Ltd. (72) Inventor Koichi Sugimoto 1-1, Komachi, Takatsuki-shi, Osaka Pref. Matsushita Electronic Kogyo Co., Ltd. (58) Field surveyed (Int. Cl. ⁷ , DB name) H01J 61/32

Claims (1)

(57) [Claims] 1. Inside, a pair of electrodes and at least mercury,
Noble gas, a luminescent metal compound is sealed, and has a first cylindrical portion and a tapered portion connected to both ends of the first cylindrical portion, and an inner diameter of the first cylindrical portion at one end of each of the tapered portions. A second tube portion smaller than the first tube portion, and a luminous tube made of ceramic in which the electrodes are fixedly held to the second tube portion such that the pair of electrodes are located inside, and the taper inside the luminous tube is provided . a Department within the surface at an angle α of 50 to 80 degrees with the axis of the electrode, and the ratio of the inner diameter D of the first cylindrical portion length of the first cylindrical portion to (mm) L (mm) is - 0.014α
A high-pressure metal vapor discharge lamp, wherein + 1.4 ≦ (D / L) ≦ 0.017α + 0.36.