JPS59108257A - Low pressure metal vapor discharge lamp - Google Patents

Abstract

PURPOSE:To obtain a discharge lamp able to distribute lights to a determined direction effectively and also to enable the form of the reflecting plate to be designed freely by providing a reflecting plate between discharge space and non-discharge space. CONSTITUTION:A discharge lamp is constituted with an external tube 1 of cylindrical form forming an air tight space, concentric cylindrical internal tube 2 installed at the approximate center of the external tube 1 and a reflecting plate 3 installed between the external tube 1 and the internal tube 2, the same air tight space as that within the external tube 1 is built within the internal tube through the opening 4 provided on the internal tube 2, a pair of electrodes 5, 5 are disposed in the vicinity of both ends of the internal tube 2, inside of the internal tube 2 is made a discharge space A and the other space within the external tube 1 is made a non-discharge space B. And the external surface area of the external tube 1 Sb constituting non-discharge space B against the external surface area Sa of the internal tube 2 constituting discharge space A, is made to satisfy Sb>=5Sa, and main discharge (luminous) material is made of metal vapor. Index 6 as shown in the drawing are the holders to fix the internal tube 2 and the reflecting plate 3.

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) Discharge lamp binding-ζ, which provides high luminance and large luminous flux, has been realized and put into practical use, for example, in high-pressure metal vapor discharge lamps such as mercury lamps. However, this type of discharge lamp
Provision 1 requires that the lamp be operated at high pressure and high temperature during steady lighting, so for several minutes after lighting starts, the inside of the tube is at low temperature and low pressure, so there is not enough light, which requires a so-called warm-up time. Another disadvantage is that if the lamp is turned off after it has been turned on and an attempt is made to turn it on, it cannot be restarted due to the high temperature and pressure inside the tube, and it takes several minutes for the lamp to be turned off before it can be restarted. 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 ugly. 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 this drawback, the applicant of the present application first provided non-discharge spaces B in the same airtight discharge spaces in a tube formed in an airtight manner, and the non-discharge spaces B were provided with respect to the outer surface area Sa of the discharge spaces A. We proposed a low-pressure metal vapor discharge lamp in which the outer surface area Sb was sb≧5・Sa (Japanese Patent Application No. 5'1-1605
No. 34) intends to effectively distribute light in a specific direction using such a discharge lamp, a configuration 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 fixture, but it has the disadvantage that the desired light distribution cannot be achieved unless the reflector plate a is formed as large as shown (needing to be at least twice as large as the lamp b), and the lamp Most of the light from b exits the outer tube 1, passes through the reflector a, enters the outer tube 1 again, and then exits again, passing through the upper and outer tube l.
There is a drawback that the loss of 1M light transmission (absorption, scattering) during this period is large. 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. .

(Objective of the Invention) The present invention was made in view of the above-mentioned drawbacks, and its object is to provide a low-pressure metal vapor discharge lamp that can efficiently distribute light in a specific direction.

(Disclosure of the Invention) FIG. 3 is a simplified sectional view showing an embodiment of the present invention, and FIG. 4 is a horizontal 117Tfih view of the same as above, showing a cylindrical outer tube 1 forming an airtight space, and the outer tube 1. It consists of a concentric cylindrical inner tube 2 disposed approximately at the center of the inner tube, and a reflection plate 3 disposed between the outer tube 1 and the inner tube 2. The same airtight space as the inside of the outer tube I is formed through the opening 4, and a pair of electrodes 5, 5 are arranged near both ends of the inner tube 2.
The inner space is defined as a discharge space A, and the other space within the outer bulb 1 is defined as a non-discharge space B. Then, the outer surface area forming the non-discharge space B, that is, the outer surface area sb of the outer tube 1, is sb with respect to the outer surface area Sa forming the discharge space, that is, the outer surface area Sa of the inner tube 2.
≧5.Sa, and the main discharge (light-emitting) substance is metal vapor. In addition, 6 in the figure is a holder for fixing the inner tube 2 and the reflection plate 3.

It goes without saying that the present invention does not need to be limited to the above-mentioned embodiments. For example, if the main discharge is contained, the inner tube 2 may be substantially omitted; Any configuration may be used as long as the space A is formed. Further, if the cross-sectional shape of the reflecting plate 3 is a paraboloid as shown in FIG. 5, the main light distribution directions will be parallel.

(Effects of the Invention) As described above, the present invention provides a discharge space A and a non-discharge space B, each of which is airtight, in a tube formed airtight, and the ratio of the non-discharge space B to the outer surface area Sa of the discharge space is The low-pressure metal vapor discharge lamp in which the outer surface area sb is sb≧5·Sa is characterized in that a reflecting plate is provided between the discharge space A and the non-discharge space B. 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, extra space is required outside the discharge lamp. Moreover, since the shape of the reflector plate 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 itself, it has the additional effect of easily providing a discharge lamp with improved starting performance and lighting stability.

[Brief explanation of the drawing]

1 and 2 are simplified sectional views of the conventional example, FIG. 3 is a simplified sectional view showing one embodiment of the present invention, FIG. 4 is a cross sectional view of the same, and FIG. 5 is a different embodiment of the present invention. FIG. 3 is a simplified cross-sectional view showing an example. 1...Outer tube, 2...Inner tube, 3...Reflector, 4...
- Opening, 5...electrode. Patent applicant Matsushita Electric Works Co., Ltd. Agent Patent attorney Toshikuro Takemoto (two idiots)

Claims (2)

[Claims] (1) A discharge space A and a non-discharge space B are provided in an airtight tube, and the outer surface area sb of the non-discharge space B is set to sb≧5 with respect to the outer surface area Sa of the discharge space A.
A low-pressure metal vapor discharge lamp characterized in that a reflector plate is provided between the discharge space A and the non-discharge space B. (2) The low-pressure metal vapor discharge lamp according to claim 1, wherein the discharge space A is constructed by arranging an inner tube having an opening inside an outer tube that forms the non-discharge space B.