JPH0452931Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Field of industrial application] The invention is suitable for use in compact fluorescent lamps, especially those with a
It concerns a compact fluorescent lamp that is 120 mm or less and has a power consumption of 2 W or less.

[Technical background]

Recently, new products such as wristwatch-type TVs and pocket TVs have been developed, and the screens of these TVs are formed using liquid crystal elements, and backlights for illuminating these liquid crystal elements are small and consume little power. Electroluminescence has been used since then. (See "Nikkei Electronics," p. 67, published January 31, 1983) However, this EL board currently does not have sufficient brightness, which causes the problem that the screen is dark.

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

Fluorescent lamps used as backlights need to be small and have low power consumption, and in practical terms, the total length of the envelope tube is
It is required that the width is 120mm or less and the power consumption is 2W 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 gap, and a heat-insulating holding material that airtightly seals both ends of the outer tube. This is achieved by a compact fluorescent lamp having a double-tube structure having an outer tube having an outer diameter of 20 mm or less, and a part of the outer tube having a mirror surface.

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 attached to the envelope tube 4 so that a space S surrounding the outer wall of the envelope tube 4 is formed between the inner wall of the outer tube 1 and the outer wall of the envelope tube 4 at an interval of about 1 to 5 mm.
, 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 embedded 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 to create a vacuum, 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 envelope tube 4, the total length L of the lamp is 120 mm or less, and the outer diameter D of the outer tube 1 is 20 mm or less. and outer tube 1
The wall thickness of the enclosure tube 4 is approximately 0.5 to 0.9 mm, and the wall thickness of the envelope tube 4 is approximately 0.3 to 0.9 mm.
It is 0.7mm.

In this example, as shown in FIG. 2, a reflective film 7 made of, for example, aluminum foil is provided over a part of the outer tube 1, for example, over approximately half of the outer wall surface or inner wall surface. Approximately half the circumference of the tube 1 has a mirror surface.

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. Not shown are 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, krypton, 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 having the above configuration, as will be understood from the explanation of the experimental examples to be described later, since approximately half the circumference of the outer bulb is a mirror surface, part of the light emitted from the discharge section is on the mirror surface side. The light directed toward the is reflected by the mirror surface and projected in the opposite direction. Therefore, the light from the discharge section can be projected in almost one direction. As a result, the light utilization rate is high and it can be used in a normal temperature atmosphere. It is quite bright, and it has a double-pipe structure, and there is a void around the outer periphery of the envelope tube, and this void is separated from the outside space by the outer tube and a heat-insulating retainer. Due to the heat retention effect, heat dissipation from the envelope tube is small, and the outer diameter of the outer tube is less than 20 mm, so the outer surface area is small, so heat dissipation from the outer tube is small, and the total length is less than 120 mm, resulting in low power consumption. Even though it is 2W or less, 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 temperature of the coldest point of the sealed tube is significantly suppressed. The mercury vapor pressure within the sealed tube is maintained at a sufficiently high level, resulting in high luminous efficiency even at low temperatures, and the efficiency of light utilization is improved, making it possible to obtain sufficient brightness. The installation space for the backlight of the liquid crystal element that makes up the screen of ultra-compact TVs and the like is naturally limited to a small space. The thickness of the lamp is also required to be small, but in this invention, the thickness of the fluorescent lamp, that is, the outer diameter of the outer tube, is set to 20 mm or less. The installation space required when incorporated into a TV is small, and the screen can be made sufficiently bright not only in a room temperature atmosphere but also in a low temperature atmosphere without hindering the downsizing of ultra-compact TVs. This provides a bright screen that is not affected by the brightness of the screen, which provides 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 I according to the present invention having the following configuration was manufactured.

Total length of sealed tube...103mm Outer diameter of outer tube...15mm Inner diameter of sealed tube...6.45mm Electrode spacing...59mm Filled gas...Argon gas Filled gas pressure...15 torr Mercury amount...1mg Filament electrode ...Wind a tungsten wire of 2.67 in MG display into a coil.Electronic emitter...Fix by coating a mixture of triple carbonate and zirconia.Empty space...2.5mm Empty pressure...Atmospheric pressure Lamp voltage... 45V Lamp current: 15mA Power consumption: 0.67W Mirror surface: Aluminum foil is placed around half of the outer bulb An experiment was conducted in which the fluorescent lamp I with the above configuration was actually turned on under various ambient temperatures. The luminance of the outer surface of the lamp was measured at each temperature, and the dependence of luminance on ambient temperature was investigated. The results are shown by solid line I in FIG.

On the other hand, for comparison, a fluorescent lamp for comparison was manufactured in the same manner except that a mirror surface was not formed on the outer tube, and a fluorescent lamp was also made in the same manner without forming a mirror surface on the outer tube.
Comparative fluorescent lamps were prepared in the same manner except that the chamber was hermetically sealed and the space was evacuated, and comparative fluorescent lamps were prepared in the same manner except that the outer tube and retaining material were not provided. Fluorescent lamp for comparison,
Similar experiments were conducted using , and. The results are also shown in Figure 3. In the figure, the broken line shows the results of the comparative fluorescent lamp, the broken line shows the results of the comparative fluorescent lamp, and the broken line shows the results of the comparative fluorescent lamp.

As can be understood from the solid line I in FIG. 3, the fluorescent lamp according to the present invention has considerably high brightness at room temperature, and the decrease in brightness with a decrease in ambient temperature is small, and the luminance at 0°C Even in a low-temperature atmosphere, the luminance was high and the brightness was sufficient. As can be understood from the solid line I and the broken line, when a mirror surface is formed on the outer tube, the brightness is approximately 1.4 times higher than when no mirror surface is formed, and the brightness can be further increased by forming a mirror surface. I understand. Also, solid line I
As can be understood from the broken line, if a mirror surface is not formed even if the air is evacuated, the brightness will be low at room temperature, and as can be understood from the broken line, it is not a double tube structure but a so-called single tube structure. In a fluorescent lamp for comparison of structure, the brightness decreases significantly as the ambient temperature decreases, and in an atmosphere as low as 0°C, the brightness is considerably reduced to approximately 16% of the maximum value, which is sufficient for practical use. I couldn't get it.

[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. The compact fluorescent lamp is characterized in that it has a double-tube structure, and has an outer diameter of 20 mm or less, and a part of the outer tube has a mirror surface. It is small and has low power consumption, is quite bright even in a room temperature atmosphere, and is not easily affected by ambient temperature even in a low temperature atmosphere, and has high luminous efficiency and can provide sufficient brightness. Therefore, 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, which is a great practical advantage.

[Brief explanation of the drawing]

1 and 2 are an explanatory longitudinal sectional front view and an explanatory side view showing one embodiment of the present invention, respectively, and FIG.
The figure is a diagram showing the ambient temperature dependence of brightness 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, 7... Reflective 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, which comprises an envelope tube, an outer tube surrounding the envelope tube with an air gap between the outer tube and the outer tube. and a heat-insulating retaining material that airtightly seals both ends of the outer tube, the outer diameter of the outer tube being 20 mm or less, and a part of the outer tube having a mirror surface. A small fluorescent lamp.