JPH06132011A - Compact low pressure mercury rare gas discharge lamp - Google Patents

Abstract

(57) [Summary] [Purpose] A small-sized low-pressure mercury rare gas discharge that can obtain higher brightness in fluorescent lamps and can emit more ultraviolet rays in ultraviolet lamps, and has a long life. Provide a lamp. [Structure] A pair of electrodes, in which a rare gas mainly consisting of argon and krypton and a small amount of mercury are enclosed in a bulb having an inner diameter of 5 mm or less, and a filament coated with an emitter is covered with a cylindrical sleeve with a bottom, The small-sized low-pressure mercury rare gas discharge lamps arranged facing each other are characterized in that the mixing amount of krypton is 10 to 40 mol% of the total rare gas, and the filling pressure of all the rare gas is 40 Torr or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-sized low-pressure mercury rare gas discharge lamp, and more specifically, a small fluorescent lamp suitably used as a light source for reading an image reader or a backlight for a liquid crystal display, or a photochemical reaction. The present invention relates to a small ultraviolet lamp that is preferably used as a germicidal lamp.

[0002]

2. Description of the Related Art Small-sized low-pressure mercury lamps are used in various fields. Among them, small-sized mercury fluorescent lamps are rapidly expanding in demand as backlights for liquid crystal displays and reading light sources for image readers. is doing. And the downsizing wave due to personalization of computers, word processors, and facsimiles has never stopped, demand for smaller, lighter, and thinner models has expanded rapidly, and backlights and light sources for reading have also become smaller and more compact. The need for brightness lamps is very high.

Further, in personal equipment, it is generally required that parts such as lamps are designed not to be replaced until the life of the product is exhausted, and it is essential that the lamps have high brightness and long life. It is a factor. Under such circumstances, as a conventional backlight, a cold cathode type small mercury fluorescent lamp, which prioritizes the extension of life, is used.

[0004]

However, in the cold cathode type compact mercury fluorescent lamp, even if it is satisfactory in terms of life, it is not sufficiently satisfactory in terms of brightness. There is a problem. In addition, the semi-hot type electrode developed by the present inventors, that is, a small mercury fluorescent lamp having an electrode in which a filament coated with an emitter is covered with a cylindrical sleeve with a bottom has a higher brightness than the cold cathode type. Although it can be used as a high lamp, there is a limit to high brightness, and a satisfactory backlight has not been obtained particularly for a liquid crystal color display. On the other hand, in the field of UV lamps for photochemical reactions and sterilization, there is a growing demand for smaller low-pressure mercury lamps that emit more UV light, but satisfactory products have not yet been developed.

The present invention has been made to solve the above problems, and its purpose is to:
It is an object of the present invention to provide a small-sized low-pressure mercury rare gas discharge lamp which can obtain a higher brightness in a fluorescent lamp, can emit a larger amount of ultraviolet rays in an ultraviolet lamp, and has a long life.

[0006]

In the small-sized low-pressure mercury rare gas discharge lamp of the present invention, a rare gas mainly containing argon and krypton and a trace amount of mercury are enclosed in a bulb having an inner diameter of 5 mm or less, and an emitter is applied. In a small-sized low-pressure mercury rare gas discharge lamp in which a pair of electrodes covering the formed filament with a cylindrical sleeve having a bottom are arranged so as to face each other, the krypton content is 10 to 40 mol% of the total rare gas. It is characterized in that the filling pressure of the rare gas is set to 40 Torr or more.

[0007]

[Function] Since a pair of electrodes in which a filament coated with an emitter is covered with a cylindrical sleeve with a bottom is used, it is resistant to sputtering against ion bombardment and can be a long-life lamp, and krypton and argon are the main constituents. Since the content of this krypton is set to 10 to 40 mol% of the total rare gas, when the filling pressure of all the rare gas is set to 40 Torr or more, as will be apparent from the experimental results described later, It can be a high brightness lamp.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a sectional view for explaining a small fluorescent lamp with an output of 3.5 W used as a backlight for a liquid crystal display, in which 1 is a bulb and 2 is a pair of electrodes arranged so as to face both ends of the bulb 1. Reference numeral 3 is a lead wire that is hermetically penetrated through the bulb 1 and connected to the electrode 2. Reference numeral 4 is a bulb 1.
It is a phosphor coated on the inner surface of.

The bulb 1 is made of lead glass having an inner diameter of 3.34 mm, a wall thickness of 0.38 mm, and a length of 260 mm.
The three-wavelength phosphor 4 mixed in a weight ratio of R: G: B = 1: 1: 1 is applied to the inner surface to a thickness of about 15 μm. In the case of an ultraviolet radiation lamp, the bulb 1 needs to be made of a material having a high ultraviolet transmittance, and for example, quartz glass is used. When used in a germicidal lamp or the like, the phosphor 4 is not usually applied, but in the case of an ultraviolet lamp used for a special purpose, the phosphor 4 that emits the necessary wavelength range may be applied.

As shown in the enlarged sectional view of FIG. 2, the electrode 2 has a filament 21 wound around a double coil, an emitter 22 applied to the filament 21, and a sleeve 2 covering the filament 21 and the emitter 22.
3 and 3. The filament 21 has a wire diameter of 30.
A tungsten wire of μm is wound around a double coil of 3 mm in length, and it is designed to have a very small heat capacity. Between the single and double filaments of this filament 21, barium, calcium, and strontium are used as emitters. Oxide is applied.
One end 21a of the filament 21 and the lead wire 3
The tip end 3a of the is held by the crushed portion 23a of the sleeve 23. A pipe made of stainless steel is used for the sleeve 23, and the tip 21b of the filament 21 is arranged at a position slightly retracted from the tip opening 23b of the sleeve 23.

In the bulb 1, a trace amount of mercury of about 3 μl and a noble gas consisting mainly of argon and krypton are contained.
More than thor is sealed, and krypton is mixed so that the content in all rare gases is 10 to 40 mol%. Krypton is encapsulated in order to increase the amount of ultraviolet radiation, and when it is 10 mol% or less, the increase in brightness is small and the effect cannot be sufficiently achieved. Again 4
When the content is 0 mol% or more, the effect of increasing the brightness cannot be obtained unless the gas pressure to be enclosed is considerably high, and not only the effect is low, but also the starting voltage rises.

FIG. 3 shows the results of an investigation of the influence of the mixing ratio of argon and krypton and the filling pressure of all noble gases on the brightness, and FIG. 4 shows the mixing ratio of argon and krypton and the filling pressure of all noble gases. It is the result of investigating the effect of the luminance on the luminance efficiency. In the investigation, three lamps with different mixing ratios of argon and krypton and the filling pressure of all noble gases were made for each plot point, and the lamps were lit by controlling the lighting current to be constant at 12 mA. It was carried out by obtaining the average value of the luminance. Also in FIG.
Is a conventional type fluorescent lamp in which 70 Torr of argon is enclosed, and a high-intensity fluorescent lamp of the present invention in which the mixing amount of krypton is 20 mol% and the rare gas mixed with Argon-Krypton is enclosed in 70 Torr. FIG. 3 is a diagram showing the relationship of the above, and is a diagram showing the maximum brightness of the conventional type as 100.

As shown in FIG. 3, when the mixing amount of krypton is 10 to 40 mol%, the brightness becomes higher than that of the conventional 100% argon gas when the filling pressure of the rare gas is 40 Torr or more. The brightness increase was about 20 to 40%. This indicates that a large amount of ultraviolet rays that excite the phosphor is generated, and when used as an ultraviolet lamp, a large amount of ultraviolet rays are emitted by an amount corresponding to increased brightness. In addition, as shown in FIG. 4, when the krypton mixing amount is 10 to 40 mol%, the luminance efficiency does not change so much even when the rare gas filling pressure is 70 Torr or more, and is 10 to 10% higher than that of the conventional type. It was up 15%. As described above, there is a demerit that the starting voltage rises when the rare gas filling pressure is increased. Therefore, it is considered that about 70 Torr is suitable as the rare gas filling pressure.

In a mercury fluorescent lamp, since the vapor pressure of mercury changes depending on the ambient temperature, it is well known that the brightness is also influenced by the ambient temperature. FIG. 5 compares the relationship between the ambient temperature and the luminance between the high-intensity type fluorescent lamp of the present invention and the conventional type fluorescent lamp. As shown in FIG. 5, since the mercury vapor pressure is low at low temperatures, ultraviolet light emission from mercury is reduced and the brightness is also reduced. Further, when the mercury vapor pressure rises as the ambient temperature rises, self-absorption of ultraviolet rays emitted from mercury occurs, and due to this self-absorption, the brightness changes with a peak at around 30 ° C. And the fluorescent lamp of the present invention is
20% more than conventional fluorescent lamps at room temperature above 0 ℃
The above brightness can be increased.

Since the small-sized low-pressure mercury rare gas discharge lamp of the present invention uses the filament coated with the emitter as the electrode covered with the cylindrical sleeve having the bottom, it has a long life. 10 to 4
A rare gas mainly containing argon containing 0 mol% of krypton is used, and it is turned on at an ambient temperature of 10 ° C or higher. Therefore, the brightness is increased by 20% or more and the amount of ultraviolet radiation is increased compared to the conventional 100% argon. Can be improved.

[0016]

As described in detail above, the small-sized low-pressure mercury rare gas discharge lamp of the present invention can increase the brightness and the amount of ultraviolet radiation without sacrificing the life of the lamp. It can be made suitable as a light source for reading an original of an image reader, or a light source for photochemistry or sterilization.

[Brief description of drawings]

FIG. 1 is a sectional view for explaining a compact fluorescent lamp according to the present invention.

FIG. 2 is an explanatory diagram of an electrode used in the present invention.

FIG. 3 is a diagram showing the relationship between the mixing ratio of argon and krypton, the filling pressure of all rare gases, and the brightness.

FIG. 4 is a diagram showing the relationship between the mixing ratio of argon and krypton, the filling pressure of all rare gases, and the luminance efficiency.

FIG. 5 is a relationship diagram between ambient temperature and relative brightness.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Bulb 2 ... Electrode 21 ... Filament 22 ... Emitter 23 ... Sleeve 3 ... Lead wire 4 ... Phosphor

Front page continuation (72) Inventor Seiichi Uesei 1194 Sado, Bessho-cho, Himeji-shi, Hyogo Ushio Denki Co., Ltd. Within

Claims (1)

[Claims] 1. A pair of a valve having an inner diameter of 5 mm or less, in which a rare gas mainly containing argon and krypton and a small amount of mercury are enclosed, and a filament coated with an emitter is covered with a cylindrical sleeve having a bottom. A small-sized low-pressure mercury rare gas discharge lamp having electrodes arranged opposite to each other, characterized in that the mixing amount of krypton is 10 to 40 mol% in the total rare gas, and the filling pressure of the total rare gas is 40 Torr or more. Compact low pressure mercury rare gas discharge lamp.