JPH09161728A - Metal halide lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lamp having good luminous efficiency and color rendering property and suitable for a high-vision illumination light source by specifying the relation between the rated lamp current and the inner diameter of a light emitting tube in the metal halide lamp sealed with Dy-Tl-Cs additives. SOLUTION: A quartz tare is full press-machined to manufacture a light emitting tube 1. Dysprosium iodide, thalium iodide, cesium iodide, mercury, and argon gas as rare gas are sealed in the light emitting tube 1. This lamp satisfies I>=10 (A), 2.3>I/D<2> >1.6, where I (A) is the rated current of the lamp, and D (cm) is the inner diameter of the light emitting tube 1. The rated lamp voltage of the light emitting tube 1 is preferably set to 100-130V. When the inner diameter is made 29.5mm or below, this lamp has the color temperature of about 5500K or below and the average color rendering index Ra of 90 or above, and it can satisfy the color characteristics.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal halide lamp, and more particularly to improvement of a metal halide lamp in which a Dy-Tl-Cs-based additive of 1 KW or more is enclosed in an arc tube.

[0002]

2. Description of the Related Art As an element for evaluating the lamp characteristics of various light sources, a color rendering property that expresses how a color looks with respect to an object to be illuminated, particularly an average color rendering index (Ra) is defined. This Ra
The high color rendering metal halide lamp having a value of 90 or more is used in many places as a light source for indoor lighting, and its lamp characteristics have been highly evaluated. In addition, with the recent full-scale high-definition broadcasting, indoor and outdoor stadiums,
Lamps with high color rendering are also required for lighting sports facilities such as stadiums.

Conventionally, metal halide lamps containing Sc-Na type additives are mainly used for lighting indoor and outdoor stadiums and other sports facilities. This is manufactured by a full press process in which a straight tube-shaped quartz glass is used for an arc tube and its end is heated and sealed as it is. On the other hand, a small lamp with a small lamp input (250 W or less), which is well known as a high color rendering metal halide lamp for indoor use, uses a Dy-Tl-Cs-based additive, and a high wattage of this type of metal halide lamp. (1 kW or more) is being promoted. Since the arc tube that encloses this additive needs to have a high end temperature,
A narrow arc-shaped arc tube is used, which is manufactured by processing quartz glass of the arc tube so that its end is thinner than the central part and sealing the part.

[0004]

By the way, Sc-Na
Metal halide lamps with system additives have good luminous efficiency,
Although the lamp characteristics are stable, the average color rendering index (Ra) is as low as about 65 due to the characteristics of the encapsulated additive, and there is a problem in that it cannot satisfy Ra80 or higher, which is suitable for a light source for high-definition broadcasting, and cannot cope with it.

On the other hand, the Dy-Tl-Cs-based additive metal halide lamp is optimal as a light source for high-definition broadcasting with a Ra of 90 or more, but the arc tube is narrow-processed during manufacturing, so the workability is poor, There is a problem that automation is difficult. Also, when processing quartz glass (joining processing of quartz glass), since the H ₂ burner is used for heating, the OH ⁻ group remains mixed in the sealing processing part, and the processing is performed during lamp lighting. There is a problem in that H ₂ is generated from some parts and causes blackening of the lamp, which affects the life characteristics of the lamp. Further, when a general-purpose full press method in which no quartz glass is connected is used as a processing method of the quartz glass and the arc tube of the additive is constituted, the vapor pressure of the additive is low, and therefore the arc tube temperature needs to be raised. However, this arc tube end structure has a problem that the temperature does not rise and a sufficient vapor pressure cannot be obtained, so that desired lamp characteristics cannot be obtained.

Generally, a high-pressure discharge lamp such as a metal halide lamp is for 100V and 2V depending on the magnitude of the line voltage.
There are two types of lamps for 00V. 100V class lamp (generally, lamp voltage is 100 to 130V)
Causes the lamp voltage to decrease and the lamp current to increase.
In addition, 200V class lamp (generally, the lamp voltage is 240 ~
270V lamp) has a limitation in lamp design that the lamp voltage becomes large and the lamp current becomes small.
In addition, since the 200V class lamp has a larger amount of mercury than the 100V class lamp, there is a problem that the lighting conditions are limited, such as arc fluctuation during vertical lighting.

The present invention has been made in view of the above, and by defining the design conditions of an arc tube manufactured by a general-purpose full-press working method, the lamp power is 1 kW or more and the lamp characteristics are good, and particularly the color rendering is performed. The purpose is to provide a metal halide lamp that has high performance and is optimal for high-vision lighting. Another object of the present invention is to provide a metal halide lamp which is capable of increasing the lamp current because the lamp voltage is low and which is stable in lamp characteristics and which is most suitable for high-vision illumination with a lamp power of 1 kW or more.

[0008]

In order to achieve the above-mentioned object, the present invention relates to dsprosium iodide, thallium iodide, and
1KW filled with cesium iodide, mercury and rare gas
In the above metal halide lamp, when the rated lamp current of the lamp is I (A) and the inner diameter of the arc tube is D (cm), I ≧ 10 (A), 2.3> I / D ² > 1.6 It is characterized by The rated lamp voltage of the arc tube is 100V to 130V.

[0009]

As described above, the arc tube of the metal halide lamp in which the Dy-Tl-Cs-based additive is enclosed is a narrow tare, but even when manufactured by general full press processing, the lamp current value is 10A or more. If so, the temperature of the electrodes sealed at both ends of the arc tube increases due to the flow of current. If I / D ² is larger than 1.6, the end temperature of the arc tube rises, and good color characteristics are obtained.
If D ² is larger than 2.3, the luminous efficiency drops sharply. Therefore, by defining the luminous efficiency during that period, good lamp characteristics can be obtained even in a full-press processed luminous tube.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a side view showing an embodiment of a metal halide lamp according to the present invention, in which 1 is a 1500 W arc tube in which main electrodes 2 and 3 are sealed at both ends of a quartz glass tube.
Inner diameter 28 mm, outer diameter 32 mm, arc length 90 m
m, the mandrel diameter of the electrode is 2.0 mm, and a quartz tare is manufactured by full pressing. In the arc tube 1, 15 mg of dysprosium iodide and 8.1 m of thallium iodide were used.
2660 Pa of g, cesium iodide 5.0 mg, mercury 40 mg, and argon gas as a rare gas are enclosed. Further, an auxiliary electrode 4 is provided near one of the main electrodes 3 of the arc tube 1, and a heat insulating film 5 made of fine particles such as zirconium oxide is deposited on the outer surfaces of both ends of the arc tube.
The arc tube 1 thus configured is held in the outer bulb 6 via the arc tube columns 7 and 8 fixed to the tip of the outer bulb 6 and the stem. Further, 9 is a lead wire for electrically connecting the other main electrode 2 and the auxiliary electrode 4, and 10 is an outer cap. The rated lamp current of this lamp is 14A.

Next, an experimental example will be described. First, the relationship between the lamp current per unit area of the arc tube and the color temperature will be described. FIG. 2 shows changes in color temperature when the inner diameter of the arc tube is changed without changing the wall load of the arc tube. It can be seen that the lamp in which the above-mentioned additive is filled satisfies the Ra of 90 or more at the color temperature of 5500K or less when the inner diameter of the arc tube is 29.5 mm or less. From this, the value of I / D ² is 1.6
With the above, the color characteristics can be satisfied.

FIG. 3 shows the relationship between the lamp current per unit area of the arc tube and the luminous efficiency. As shown in FIG. 3, when the value of I / D ² is 2.3 or more, the light emission efficiency drops sharply, the light emission efficiency becomes lower than 80 lm / W, and the lamp characteristics cannot be satisfied. These phenomena occur when the rated lamp current is 10 A or more, and the radiation of heat from the electrodes due to the lamp current cannot obtain such an effect when the current value is smaller than 10 A. Therefore, as described above, the relationship between the lamp rated current I and the inner diameter D of the arc tube is I ≧ 10, 2.3> I / D ² >
When it is specified as 1.6, good lamp characteristics can be obtained in the metal halide lamp having the above configuration.

In the above embodiment, the lamp power is 1500 W,
Although a metal halide lamp having a lamp current of 14 A and a lamp voltage of 120 V has been described, substantially the same effect as the above is recognized as long as the lamp has a lamp power of 1 kW or more and a lamp current of 10 A or more and contains the above-mentioned additive.

[0014]

As described above based on the embodiments, according to the present invention, in a metal halide lamp of 1 kW or more in which a Dy-Cs-Tl-based additive is enclosed in the arc tube, a straight tube quartz is used as the arc tube. Even if a glass is used in a full-press shape, the light emission efficiency and color rendering properties are good, and a metal halide lamp most suitable as a light source for high-definition lighting can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of a metal halide lamp according to the present invention.

FIG. 2 is a characteristic diagram showing a relationship between a lamp current per unit area of an arc tube and a color temperature.

FIG. 3 is a characteristic diagram showing the relationship between the lamp current per unit area of the arc tube and the luminous efficiency.

[Explanation of symbols]

 1 arc tube 2,3 main electrode 4 auxiliary electrode 5 heat insulating film 6 outer bulb 7,8 arc tube support 9 lead wire 10 base

Claims (2)

[Claims] 1. An arc tube obtained by full-pressing a straight-lined quartz-made tare container is filled with dysprosium iodide, thallium iodide, cesium iodide, mercury, and a rare gas.
In a metal halide lamp of KW or more, if the rated lamp current of the lamp is I (A) and the inner diameter of the arc tube is D (cm), I ≧ 10 (A), 2.3> I / D ² > 1.6 Metal halide lamp characterized by doing 2. The arc tube has a rated lamp voltage of 100.
The metal halide lamp according to claim 1, which has a voltage of V to 130V.