JPH0452932Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a compact fluorescent lamp, particularly a compact fluorescent lamp with a total length of 120 mm or less and a power consumption of 2 W or less.

[Technical background]

Recently, new products such as color pocket TVs have been developed, and the screen of these TVs is formed using liquid crystal elements.As a backlight to illuminate this liquid crystal element, EL (EL) is used because it is small and has low power consumption. (electroluminescent) plates are used. (See page 67 of Nikkei Electronics, January 31, 1983).

However, this EL board currently does not have sufficient brightness, resulting in a dark screen.

For this reason, the present inventor has considered using a fluorescent lamp as a backlight.

Fluorescent lamps used as such backlights need to be compact and have low power consumption, and practically require a total length of 120 mm or less and power consumption of 2 W or less.

However, in fluorescent lamps that are small and have low power consumption, the amount of heat generated when the lamp is turned on is small, and the heat capacity is also small, so the temperature of the envelope tube when the lamp is turned on is greatly affected by the ambient temperature. Therefore, at low temperatures, such as when the ambient temperature is 5°C or less, the temperature of the envelope tube of a fluorescent lamp does not rise sufficiently, and as a result, the temperature of the coldest point of the envelope becomes low. There is a problem in that the mercury vapor pressure within the envelope tube decreases, resulting in a decrease in issuing efficiency and the inability to provide sufficient brightness of illumination.

[Purpose of invention]

The present invention was developed based on the above-mentioned circumstances.It is small in size, has low power consumption, is quite bright in a normal temperature atmosphere, and is not affected by the ambient temperature even in a low temperature atmosphere, and has high luminous efficiency. The purpose of the present invention is to provide a compact fluorescent lamp that can provide sufficient brightness.

[Structure of the idea]

The above objectives are to have a total length of 120 mm or less and to reduce power consumption.
A fluorescent lamp of 2W or less, which includes an enclosed tube, an outer tube that surrounds the enclosed tube with an air in between, and a heat-insulating retaining material that airtightly seals both ends of the outer tube. This is achieved by a compact fluorescent lamp characterized in that it has a double tube structure and the outer diameter of the envelope tube is 6 mm or less.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is an explanatory diagram showing an example of a fluorescent lamp according to the present invention. 1 is an outer tube made of glass; 4 is an airtight sealed tube made of glass;
A double pipe structure is formed by the envelope tube 4 and holding materials 6, 6, which will be described later. The outer tube 1 is connected to the envelope tube 4 so that a space S surrounding the outer wall of the envelope tube 4 is formed at an interval of about 1 to 10 mm between the inner wall of the outer tube 1 and the outer wall of the envelope tube 4.
, and both are held by heat insulating holding materials 6, 6 at both ends of each.
In the illustrated example, the ends 41, 41 of the sealed tube 4 are buried and fixed in the retainers 6, 6, respectively, and these retainers 6, 6 are respectively embedded in the ends 11, 11 of the outer tube 1.
The outer tube 1 is hermetically sealed by being hermetically fitted, and a double tube structure is constituted by the envelope tube 4, the outer tube 1, and the holding members 6, 6. The air S is preferably reduced in pressure and evacuated, in which case the envelope tube 4 and the outer tube 1 are
It is possible to further improve the heat insulation properties between the two. A fluorescent film 42 is provided on the inner wall surface of the sealed tube 4, the total length L of the lamp is 120 mm or less, and the outer diameter d of the sealed tube 4 is 6 mm or less. The outer diameter D of the outer tube 1 is preferably 20 mm or less, and the wall thicknesses of the envelope tube 4 and the outer tube 1 are, for example, about 0.3 to 0.7 mm.

Reference numerals 2 and 2 indicate filament electrodes, which are fixed in position within the space at both ends of the envelope tube 4 so as to face each other by lead wires 3 and 3, respectively. Although not shown, the filament electrodes 2, 2
It is also possible to replace either one of them with a ring-shaped, plate-shaped, or rod-shaped metal electrode. The distance between the filament electrodes 2, 2 is, for example, 100 mm or less. The filament electrodes 2, 2 are made of a high melting point metal such as tungsten or molybdenum, and are in the form of, for example, a single, double or triple coil, or a straight line, and an electron emitter is fixed to the metal wire by, for example, coating. The weight of the coil portion to which the electron emitter is fixed is preferably about 0.3 to 5.0 mg, for example. This is because the weight reduction reduces the power consumption during preheating, and the heat capacity is small, making it easier to raise the temperature. Materials for the electron emitter include oxides or carbonates of alkali metals and alkaline earth metals,
Other materials commonly used as electron emitters can be used. The lead wires 3, 3 are composed of a diamond wire, a Kovar wire, or the like. In the case of lighting with direct current, one of the filament electrodes 2, 2 functions as a hot cathode, and in the case of lighting with alternating current, both of the filament electrodes 2, 2 function as a hot cathode.

For example, a mercury-impregnated alloy 5, 5 is fixed to the lead wires 3, 3 in the envelope tube 4, and by thermal decomposition, a trace amount of mercury, for example, about 0.5 to 3.0 mg, enters the envelope tube 4. In addition to enclosing mercury so that it can be released,
A gas selected from argon or neon, or a mixture thereof, of about 6 to 50 Torr is sealed.

Then, when the lamp is turned on, power is supplied to the fluorescent lamp so that the power consumption is 2W or less.

[Function and effect of the example]

According to the compact fluorescent lamp with the above configuration, as will be understood from the explanation of the experimental examples described below, the outer diameter of the envelope tube is 6 mm or less, so the cross-sectional area of the discharge part is small and the power consumption is low. In the same case, the discharge current density is higher and the amount of heat generated is larger than that of a sealed tube with a larger outer diameter, and the distance between the inner wall of the sealed tube and the arc formed on the filament electrode tube when lighting is It is small in size, so the amount of heat received per unit area of the envelope tube is large, and it has a double-pipe structure with a void around the outer periphery of the envelope tube. Because it is separated from the space,
Due to the heat retention effect of the air, the heat loss of the envelope tube is small, so when the light is turned on, the temperature of the tube wall of the envelope tube increases sufficiently, so the total length is 120 mm or less and the power consumption is 2W or less. Despite this, the temperature of the sealed tube is high even at low temperatures, such as when the ambient temperature is below 5°C, and as a result, the decrease in the coldest point temperature of the sealed tube is greatly suppressed, and the temperature inside the sealed tube is The mercury vapor pressure is maintained sufficiently high, and as a result, it is quite bright at room temperature, and even at low temperatures, the luminous efficiency is high and sufficient brightness can be obtained. From this, when used as a backlight for a liquid crystal element, the screen can be made sufficiently bright not only in a room temperature atmosphere but also in a low temperature atmosphere.
In the end, a bright screen can be obtained regardless of the ambient temperature, resulting in great practical benefits.

[Experiment example]

Next, an example of a lighting experiment conducted by actually manufacturing a fluorescent lamp according to the present invention will be described. A fluorescent lamp according to the present invention having the following configuration was manufactured.

Total length...120mm Outer tube outer diameter...16.4mm Envelope tube outer diameter...4.1mm Empty spacing...5.2mm Electrode spacing...82mm Filled gas...Argon gas Filled gas pressure...25 Torr Mercury amount... ...1mg Material of filament electrode ...Tungsten Electron emitter ...A mixture of barium, strontium, and calcium carbonates added with zirconia is fixed by coating Lamp voltage ...76V Lamp current ...15mA Power consumption ...1.1W Experiments were conducted in which the fluorescent lamp having the above configuration was actually turned on at various ambient temperatures, and the luminance of the outer surface of the lamp was measured at each temperature to investigate the dependence of luminance on ambient temperature. The results are shown by solid line I in FIG.

On the other hand, for comparison, a comparative fluorescent lamp A was prepared in the same manner except that the outer tube and the holding material were not provided and the outer diameter of the envelope tube was 7.75 mm. A similar experiment was carried out using a comparative fluorescent lamp B having a double tube structure, which was manufactured in the same manner except that the diameter was set to mm. The results are also shown in Figure 2. In the same figure, the broken line indicates the results for comparison fluorescent lamp A.
The dash-dotted line represents the results for comparison fluorescent lamp B.

As can be understood from the solid line I in FIG. 2, the fluorescent lamp according to the present invention has considerably high brightness even in a normal temperature atmosphere, and the decrease in brightness due to a decrease in ambient temperature is small, and Even in a low temperature atmosphere, the brightness was high at about 21,000 nt, which was sufficient, and the reduction rate was small at less than 30% compared to the brightness value under optimal temperature conditions (30 to 50 degrees Celsius).

On the other hand, as can be seen from the broken lines and dashed-dotted lines, the comparative fluorescent lamps A and B have considerably low brightness even in a normal temperature atmosphere, and their brightness significantly decreases in a low-temperature atmosphere of 0°C. The reduction rate was quite large, over 50%, and in the end it was not possible to obtain sufficient brightness for practical use.

[Effect of idea]

As explained in detail above, the present invention has a total length of
A fluorescent lamp with a size of 120 mm or less and a power consumption of 2 W or less, which includes a sealed tube, an outer tube surrounding the sealed tube with an air in between, and a heat insulator that airtightly seals both ends of the outer tube. This compact fluorescent lamp has a double-tube structure with a heat-retaining material, and the outer diameter of the envelope tube is 6 mm or less. In addition to being fairly bright at low temperatures, it is not easily affected by ambient temperature and has high luminous efficiency, providing sufficient brightness even in low-temperature environments. For this reason, when used as a backlight for a liquid crystal element, the screen can be made sufficiently bright not only in a normal temperature atmosphere but also in a low temperature atmosphere, and a great practical benefit can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an explanatory sectional view showing one embodiment of the present invention, and FIG. 2 is a diagram showing the dependence of brightness on ambient temperature in a fluorescent lamp according to the present invention and a comparative fluorescent lamp. 1... Outer tube, 2, 2... Filament electrode,
3,3...Lead wire, 4...Enclosed tube, 5,5...
Mercury-impregnated alloy, 6,6...holding material, S...empty,
42... Fluorescent film.

Claims (1)

[Scope of Claim for Utility Model Registration] A fluorescent lamp with a total length of 120 mm or less and a power consumption of 2 W or less, comprising an envelope tube, an outer tube surrounding the envelope tube with an air gap between the outer tube and the outer tube. 1. A small fluorescent lamp, characterized in that it has a double tube structure with a heat insulating holding material that airtightly seals both ends, and the outer diameter of the sealed tube is 6 mm or less.