JPH04282529A - Fluorescent lamp - Google Patents

Abstract

PURPOSE:To provide a structure with bases further a small size in high efficiency by facilitating handling with simple constitution. CONSTITUTION:Bases 8 are attached to both end parts of a light emitting tube 1, and external lead-in wires 7, drawn out to the outside from the end parts of this light emitting tube and formed of elastic material, are flexed into a coil shape in a condition not in contact with each other to electrically connect each point end of these external lead-in wires 7 to the bases 8.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent lamp used as a backlight for a liquid crystal panel.

0002

[Prior Art] Recently, small devices such as portable televisions, word processors, and video cameras equipped with liquid crystal panels have been developed.
A small fluorescent lamp is used as a backlight for the liquid crystal panel. These fluorescent lamps are required to have low power consumption and high efficiency, are usually used with a lamp current of 50 mA or less, and are required to have a structure that is easy to install and replace in equipment.

Conventionally, cold cathode fluorescent lamps have been mainly used for such backlights.

0004

[Problems to be Solved by the Invention] However, cold cathode fluorescent lamps have low luminous efficiency due to large electrode loss. On the other hand, hot cathode fluorescent lamps have the feature of low electrode loss, but because the calorific value of the electrodes is small, the coldest part is formed behind the electrodes, making it difficult for the vapor pressure of mercury to rise, and heat There was a problem in that the original high efficiency feature of cathode fluorescent lamps was lost. This was particularly noticeable when the lamp structure was such that a cap was attached to the end of the arc tube in order to facilitate attachment of the lamp to equipment and lamp replacement.

The present invention has been made to solve these problems, and provides a compact, high-efficiency fluorescent lamp that can be easily attached to and detached from equipment, and that suppresses the temperature drop in the coldest part of the lamp. It is something to do.

[0006]

[Means for Solving the Problems] In order to solve these problems, the fluorescent lamp of the present invention has a lamp current of 50 m.
In a device that is lit under A or below, an electrode coated with an electron radioactive substance is held by an internal lead-in wire and sealed to the end of the arc tube, and a cap is attached to the end of the arc tube, The internal lead-in wire and the base are electrically connected to each other by a bent external lead-in wire in a non-contact state, and the external lead-in wire is made of an elastic material.

[0007]

[Function] In a small hot cathode fluorescent lamp with a small lamp current, if a cap is attached to the end of the arc tube, the luminous efficiency will be greatly reduced. According to the inventor's study, this is
This is because the heat at the end of the arc tube escapes to the cap through the external lead-in wire, and the temperature of the coldest part formed near the base of the internal lead-in wire decreases, reducing the mercury vapor pressure inside the arc tube. I understand.

On the other hand, in the fluorescent lamp of the present invention, the external lead-in wires of the arc tube are bent without contacting each other.
Since the internal lead-in wire is connected to the cap, the length of the external lead-in wire to the cap is longer than before, which prevents heat from the end of the arc tube from escaping to the cap via the external lead-in wire. can do. Moreover, since an elastic material is used for the external lead-in wire, it becomes easy to ensure that the external lead-in wire is kept in a non-contact state.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, a glass bulb 2 of an arc tube 1
A glass glass holding two internal lead-in wires 3 is attached to both ends of the glass glass.
4 is sealed. Both internal lead-in wires 3 carry an electrode 5 and a getter 6 on which an electron-emitting substance is deposited. Further, an external lead-in wire 7 made of an elastic material is connected to one of the pair of internal lead-in wires 3, and this external lead-in wire 7 is bent into a coil shape and attached to the end of the arc tube 1. The cap 8 is electrically connected to the cap 8. The wire diameter of the external lead-in wire 7 is smaller than the wire diameter of the inner lead-in wire 3, thereby suppressing the escape of heat through the external lead-in wire 7. The cap 8 is located at a distance l that is more than 2.5 times the wire diameter of the external lead-in wire 7 between it and the end surface of the arc tube 1, and is bent into the space 9 formed between them. An external lead-in line 7 is housed. Thereby, the external lead-in wires 7 can be bent without contacting each other within the space 9 while ensuring a long effective length.

The getter 6 has a getter material such as zircon powder attached to one surface of the substrate and a mercury compound attached to the other surface, and mercury is released into the glass bulb 2 by heating. It is also used to absorb impure gases. In addition to the mercury mentioned above, a rare gas such as argon is sealed inside the glass bulb 2, and a phosphor layer 10 is formed on the inner surface of the glass bulb 2.

Next, a specific example of the fluorescent lamp of the present invention will be described. Lamp total length L
40mm glass bulb outer diameter D
4.1mm internal lead-in wire material
Iron, chromium, manganese alloy wire diameter
0.3mm external lead-in wire material
Stainless steel wire diameter
0.2mm lead-in wire length
15m
m (coiled) Distance between the cap and the end of the arc tube l 2
mm electrode
filament coil electron radioactive material
BaO, SrO, CaO phosphor
Three-wavelength rare earth phosphor emission color
8000K sealed gas
argon 4
When 10 lamps with 0 Torr specifications above were lit at high frequency with a lamp current of 10 mA at an ambient temperature of 25°C,
High brightness of 16,000 cd/m2 on average was obtained at the center of the arc tube.

On the other hand, in a conventional fluorescent lamp, the arc tube is the same as above, and the external lead wire is directly connected to the cap without bending, without creating a space between the end surface of the arc tube and the cap, the center of the arc tube The brightness of the area was 12,000 cd/m2.

As is clear from the above comparison, it can be seen that the fluorescent lamps of the embodiments of the present invention can significantly improve the luminous efficiency compared to the conventional ones.

[0015] In the above embodiment, a case was described in which a filament coil was held as an electrode by two internal lead-in wires, but in the present invention, the electrode may have a thin plate shape, a cylindrical shape, or a composite shape with a coil. In addition, the present invention may be applied to cases where these electrodes are held by a single internal lead-in wire, or where the electron emitting substance is other substances such as ThO or LaB6, and as long as it is a fluorescent lamp that operates as a hot cathode. Of course, similar effects can be obtained by doing so.

Furthermore, in the above embodiment, the case where both sides are hot cathode type fluorescent lamps has been described, but the present invention can also be practiced in the case where one side is a hot cathode type and the other side is a cold cathode type fluorescent lamp, and in this case, Similar effects can be obtained by implementing the present invention only on the hot cathode side.

[0017]

As explained above, in the present invention, the external lead-in wires of the arc tube are bent without contacting each other, and the tips of the wires are connected to the cap. Heat from the end can be prevented from escaping to the cap, the temperature of the coldest part can be kept high, and the mercury vapor pressure inside the arc tube can be increased. Furthermore, since the present invention uses an elastic material as the external lead-in wire, even if the external lead-in wire is deformed due to temporary force applied when assembling the cap, the external lead-in wire will return to its original state. It is possible to maintain a non-contact state with each other. In addition, the elastic action allows the external lead-in wire to be connected to the base, thereby eliminating the need for processes such as soldering. Therefore, the present invention can provide a compact, high-efficiency fluorescent lamp with a simple lamp structure that is equipped with a base and is easy to use.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a fluorescent lamp that is an embodiment of the present invention.

[
Explanation of symbols] 1 Arc tube 2 Glass bulb 3 Internal lead-in line 5 Electrode 7 External lead-in line 8 Base 9 Space

Claims (1)

[Claims] Claims: 1. A fluorescent lamp that is operated with a lamp current of 50 mA or less, in which an electrode coated with an electron radioactive substance is held by an internal lead-in wire and sealed to an end of an arc tube;
A cap is attached to the end of the arc tube, and the internal lead-in wire and the cap are electrically connected by an external lead-in wire bent in a non-contact state, and the external lead-in wire is made of an elastic material. A fluorescent lamp characterized by comprising: