JPH0117231B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a completely new low-pressure discharge lamp that has high brightness and provides a large luminous flux.

(Background Art) High-pressure metal vapor discharge lamps such as mercury lamps have been realized and put into practical use as discharge lamps that can provide high luminance and large luminous flux. However, this type of discharge lamp is designed to operate at high pressure and high temperature during steady lighting, so for several minutes after lighting starts, there is a so-called warm-up period in which the inside of the tube is low temperature and low pressure, so there is not enough light. In addition, if you turn off the light after it has been turned on and try to turn it on again immediately, you will not be able to restart it due to the high temperature and pressure inside the pipe, and it will take several minutes after the light is turned off before it can be restarted. There is a drawback. Furthermore, even if you try to obtain the desired light color and color temperature, the number of practically usable discharge (light-emitting) substances is limited to a few types, so the light color and color temperature will be specific, making it difficult to design freely. It also has the disadvantage of being difficult. Furthermore, due to the high temperature, general soft glass cannot be used, and expensive quartz glass, polycrystalline alumina tubes, etc. are required, and processing is also expensive.

In order to improve these drawbacks, the applicant of the present application previously proposed the following low-pressure metal vapor discharge lamp (Japanese Patent Laid-Open No. 59-68161).

The low-pressure metal vapor discharge lamp is comprised of a cylindrical outer tube forming an airtight space and a concentric cylindrical inner tube disposed approximately at the center of the outer tube, with both ends of the inner tube open; A pair of electrodes are disposed in both openings,
The inside of the inner tube is defined as a discharge space A, and the other space inside the outer tube is defined as a non-discharge space B. Then, the outer surface area (outer surface area of the inner tube) Sb forming the non-discharge space B with respect to the outer surface area (outer surface area of the inner tube) Sb forming the discharge space A is set to Sb≧5・Sa, and the main discharge (light-emitting) material is converted into metal vapor.

As mentioned above, since the above-mentioned discharge lamp is a low-pressure metal vapor discharge, its operating materials are essentially the same as a fluorescent lamp, and it reaches sufficient brightness immediately after starting, and can be re-lit after being turned off. can be done immediately. Also,
Since the non-discharge space B is extremely wider than the discharge space A (Sb≧5・Sa), and each discharge space A and B form the same airtight space through the opening, the coldest temperature of the metal vapor is , the temperature is sufficiently lower than the temperature inside the discharge space, and highly efficient radiation can be maintained. Therefore, although the temperature of the discharge space is higher than that of a single-tube discharge lamp consisting only of the discharge space A, the coldest temperature is regulated by the non-discharge space B, so it is lower. The difference becomes larger as the above B/A becomes larger. This becomes very effective when increasing the lamp input and aiming for high brightness and large luminous flux.

By the way, when attempting to effectively distribute light in a specific direction using the discharge lamp as described above, configurations as shown in FIGS. 1 and 2 can be considered. What is shown in Fig. 1 is the use of a so-called reflector plate device, but it has the disadvantage that the desired light distribution cannot be achieved unless the reflector plate a is made as large as shown (needing to be at least twice the size of the lamp b), and the lamp b Most of the light passes through the outer tube 1 three or more times, such as once exiting the outer tube 1, passing through the reflector a, entering the outer tube 1 again, and exiting again, resulting in light transmission loss during this time. It has the disadvantage of high absorption and scattering. On the other hand, the one shown in Fig. 2 has a reflective film c formed on the inner surface of the outer tube 1, and although it has the advantage of not taking up as much space as the former, it is difficult to obtain an arbitrary or desired light distribution. , the cross-sectional shape of the outer tube 1 cannot be determined unambiguously, and it is generally difficult and complicated to coat the inner surface of the outer tube 1 with a reflective film c having a high reflectance. .

(Object of the Invention) The present invention has been made in view of the above-mentioned drawbacks, and its purpose is to provide a low-pressure metal vapor discharge lamp that has high brightness and a large luminous flux, and can efficiently distribute light in a specific direction. There is something to do.

(Disclosure of the Invention) FIG. 3 is a sectional view showing one embodiment of the present invention, and FIG.
The figure is a simplified cross-sectional view of the same as above, and shows a cylindrical outer tube 1 forming an airtight space, a concentric cylindrical inner tube 2 disposed approximately at the center of the outer tube 1, and an outer tube 1. Inner tube 2
and a reflecting plate 3 disposed between the inner tube 2 and the inner tube 2.
Inside, the same airtight space as the inside of the outer tube 1 is formed through an opening 4 provided in the inner tube 2, and a pair of electrodes 5, 5 are arranged near both ends of the inner tube 2. is defined as a discharge space A, and other spaces within the outer bulb 1 are defined as a non-discharge space B. Then, the outer surface area forming the discharge space A, that is, the outer surface area Sa of the inner tube 2, and the outer surface area forming the non-discharge space B, that is, the outer surface area Sb of the outer tube 1, is Sb≧5・Sa, and the main discharge (light-emitting) material Let be metal vapor. In the figure, 6 is a holder for fixing the inner tube 2 and the reflecting plate 3, 7 is a fluorescent body, 8 is a stem, and 9 is an exhaust pipe.

Here, the outer tube 1 is formed of a general transparent soft glass tube, and has a diameter of 38 mm and a total length of 350 mm.
The inner tube 2 is made of a transparent hard glass tube, has a diameter of 6 mm, and has a rare earth phosphor 7 coated on its inner surface. The reflecting plate 3 has a semicircular cross section and is made of a nickel plate with a mirrored inner surface. The stem 8 is a so-called button stem made of glass or ceramic, and the holder 6 is made of ceramic. Also,
Several tens of milligrams of mercury and several Torr of argon are sealed inside the outer tube 1.

Next, an example of the manufacturing method will be briefly explained. First, the protrusions of the holder 6 are inserted into both ends of the inner tube 2, and then both ends of the reflector 3 are fixed to the holder 6 with a thermosetting inorganic adhesive or the like. Then, the open end of one holder 6 and the inner surface of the stem 8 to which the exhaust pipe 9 is sealed are glued, and this is then inserted into the outer tube 1, which is separately sealed with one open end to the other stem 8 with glass frit. At the same time, the open end is brought into contact with the stem 8, and the corresponding contact portion is hermetically sealed with glass frit. Thereafter, gas is filled in through the exhaust pipe 9 in the usual manner, and activation, sealing, etc. are performed to complete the structure.
In addition, in order to prevent damage to the contact part due to thermal expansion, variation in dimensional accuracy, etc. during processing, a soft cushioning material such as a cover sheet may be provided at the contact part as necessary.

In the above example, when the lamp current is 0.2A, the lamp voltage is 100V, the lamp power is 20W, the luminous flux is 500m, and the surface temperature of the inner tube 2 is approximately 120℃ (ambient temperature
20℃), the coldest temperature of mercury (inner surface of outer tube 1) is about 50℃,
A reflective light source that can provide a linear light source with 4 to 5 times the brightness of a general 10W fluorescent lamp with approximately the same external shape as this example, and can also provide effective light distribution in a specific direction. I was able to get

It goes without saying that the present invention is not limited to the above embodiments. Furthermore, if the shape of the reflecting plate 3 is made parabolic as shown in FIG. 5, the main light distribution directions will be parallel.

(Effects of the Invention) As described above, the present invention provides an inner tube having an opening in the outer tube and forming the discharge space A within the outer tube that is airtight and forms the non-discharge space B, and the inner tube that forms the discharge space A. In a low-pressure metal vapor discharge lamp in which the outer surface area Sb of non-discharge space B with respect to the outer surface area Sa of space A is Sb≧5・Sa, and the main discharge substance is metal vapor, the light emitted from the inner tube is arranged inside the outer bulb. It is characterized by the provision of a reflective plate for light control. Therefore, in a low-pressure metal vapor discharge lamp that is compact, can be turned on instantly, and can provide high brightness and large luminous flux, when trying to effectively distribute light in a specific direction, it is necessary to install unnecessary external parts of the discharge lamp. Since no space is required and the shape of the reflector can be freely designed, a discharge lamp having a desired specific light distribution can be easily provided. Furthermore, most of the reflected light reflected by the reflector plate passes through the outer tube only once and exits the tube, so it is possible to provide a discharge lamp with low light transmission (absorption, scattering) loss and high light distribution efficiency. Furthermore, since it is easy to impart conductivity to the reflector plate itself, it has the additional effect of easily providing a discharge lamp with improved starting performance and lighting stability.

[Brief explanation of drawings]

Figures 1 and 2 are simplified sectional views of the conventional example;
The figure is a cross-sectional view showing one embodiment of the present invention, FIG. 4 is a simplified cross-sectional view of the same, and FIG. 5 is a simplified cross-sectional view showing a different embodiment of the present invention. 1...Outer tube, 2...Inner tube, 3...Reflector, 4...
...opening, 5...electrode.

Claims (1)

[Scope of Claims] 1. An inner tube having an opening in the outer tube and forming a discharge space A is provided in an outer tube that is airtight and forms a non-discharge space B, and the outer surface area of the discharge space A is
In a low-pressure metal vapor discharge lamp in which the outer surface area Sb of the non-discharge space B with respect to Sa is Sb≧5・Sa and the main discharge substance is metal vapor, a reflector plate that controls the distribution of light emitted from the inner tube into the outer tube. A low-pressure metal vapor discharge lamp characterized by being provided with.