JPH02257559A - Flat type fluorescent lamp - Google Patents

Abstract

PURPOSE:To simplify encapsulation of mercury and reduce crack initiation at the seal part by forming a pair of cold cathodes from Hg alloy, and by forming lead-in terminals from a thin wire or foil having a low thermal conductivity. CONSTITUTION:When mercury is to be encapsulated in a flat sealed vessel 16, a pair of cold cathodes 17a, 17b are high frequency heated upon exhaustion of the vessel 16, which causes evaporation of a certain amount of mercury from the cold cathodes 17a, 17b consisting of Hg alloy, and it is encapsulated in the vessel 16. The heat from high temp. heated cold cathodes 17a, 17b is conducted to Dumet wires 19a, 19b, respectively. Low thermal conductivity of these Dumet wires 19a, 19b suppresses heat conduction from the cold cathodes 17a, 17b to the seal part to lead to prevention of this part from temp. rise, and also crack initiation at the seal part can be reduced. Use of a foil of a conductor in lieu of Dumet wire will provide the same effect.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a flat fluorescent lamp suitable for backlighting a liquid crystal display panel such as a liquid crystal television from the back side. This invention relates to a flat fluorescent lamp with an improved cold cathode and introduction terminal.

(Prior art) Conventionally, as this type of flat fluorescent lamp, Japanese Patent Laid-Open No. 62
There is a flat fluorescent lamp 1 shown in Japanese Patent No. 208537, which is constructed as shown in FIGS. 5 to 8, and includes a front plate 2 made of a single transparent plate glass,
A back plate 3 made of a single sheet of glass having the same shape and size is arranged concentrically and facing each other.

Also, between the outer peripheries of both plays 1-2.3,
A glass spacer frame 4 assembled into a rectangular frame is airtightly interposed and fixed by, for example, a glass frit, thereby forming a flat sealed container 5 in the shape of a flat rectangular box.

The flat airtight container 5 has a pair of cold cathodes 6a and 6b, such as hollow cathode cold cathodes, spaced apart from each other and facing each other inside thereof, and a discharge space 7 in which discharge is caused between the pair of cold cathodes 6a and 6b. It is formed in an oblate shape.

The air inside the flat airtight container 5 is exhausted through a circular exhaust pipe 8, and at least one rare gas such as xenon, krypton, argon, neon, helium, etc. is introduced into the flat airtight container 5 through the exhaust pipe 8. A predetermined m of mercury is sealed.

(Problem to be Solved by the Invention) However, in such a conventional flat fluorescent lamp 1, when a predetermined amount of mercury is sealed in the airtight container 5, the mercury must be granulated and passed through the exhaust pipe 8 to the table. Since it is inserted into the container 5, the light emitting surface around this particulate mercury has high brightness, while the area other than this part has low brightness, and the lamp averages 1ift.
There is a problem in that it lowers the brightness and also causes uneven brightness.

In order to improve this, as a method of enclosing an appropriate amount of mercury,
There is a method in which a pair of cold cathodes 6a and 6b are made of a mercury alloy, and during the manufacturing process, the cold cathodes 6a and 6b are heated with high frequency to evaporate the mercury, and the mercury is sealed in the table container 5.

However, with this method, cracks are likely to occur in the sealing portions that seal the pair of plate-shaped lead pieces 9a and 9b, which are respectively connected to the pair of cold cathodes 68.6b, which significantly reduces the yield during manufacturing. There is a challenge to reduce this.

That is, as shown in FIG. 5, the pair of lead pieces 9a and 9b hermetically penetrate the frit glass 10 that airtightly connects the spacer frame 4 and the back plate 3, and extend to the outside.
It is connected to a required electrical circuit (not shown).

Therefore, a pair of cold cathodes 6a and 5b made of mercury alloy
is heated to, for example, about 800 to 900°C by high frequency heating, and the heat of the pair of cold cathodes 6a, 6b is transferred to each lead piece 9a, 9b, causing elongation.
These lead plugs 9a.

Thermal stress occurs in the frit glass 10 that seals the glass 9b, making it easy to crack and impairing the airtightness of the flat closed container 5.

Therefore, the present invention was made in consideration of the above-mentioned circumstances, and its purpose is to simplify mercury encapsulation and to solve the problem of cracks occurring in the sealing part that seals a pair of lead-in terminals connected to a pair of cold cathodes. It is an object of the present invention to provide a flat fluorescent lamp which can reduce the amount of oxidation and improve the yield during manufacturing.

[Structure of the invention]

(Means for Solving the Problems) The present invention comprises a pair of cold cathodes made of a mercury alloy, and each introduction terminal connected to the cold cathodes has a low thermal conductivity of mI! i1 or formed from a foil body,
It is composed as follows.

That is, the present invention provides a method in which a pair of cold cathodes are notated facing each other in a discharge space within a flat closed container, and each part of a pair of introduction terminals respectively connected to these cold cathodes is passed through the flat closed container in an airtight manner. In the planar fluorescent lamp which extends outside, the pair of cold cathodes are each made of a mercury alloy, and each of the introduction terminals is made of either a thin wire with low thermal conductivity or a foil made of an s'R body. It is characterized by the fact that it has been formed.

(Function) By heating a pair of cold cathodes made of a mercury alloy, for example, by high-frequency heating, mercury is evaporated from each cold cathode,
Mercury can be sealed in a flat airtight container.

Furthermore, when heating such a pair of cold cathodes, the heat is transferred to the inlet terminal allIIIA or the foil body, but since the i-line and the foil body have low thermal conductivity, it is difficult to , the temperature difference between these ms and the sealing part that seals the foil body can be kept low.

For this reason, the thermal stress applied to the sealing portion can be reduced, so that the occurrence of cracks in the sealing portion can be reduced. As a result, it is possible to improve the yield when manufacturing a flat fluorescent lamp.

(Example) Examples of the present invention will be described below based on FIGS. 1 to 4.

FIG. 1 is an exploded perspective view showing the overall configuration of an embodiment of the present invention. In the figure, a flat fluorescent lamp 11 is used as a backlight for illuminating a liquid crystal spring such as a liquid crystal television from the back.
A front plate 1-12 made of a single transparent glass plate and a back plate 13 made of a single glass plate of the same shape and size are arranged concentrically and facing each other.

Moreover, between the outer peripheral edges of these plates 12 and 13,
With a spacer frame 14 of a rectangular glass frame interposed therebetween, as shown in FIG.
It constitutes a flat container 16 in the shape of a flat rectangular box.

The front plate 12 has a fluorescent film (not shown) coated almost entirely on its inner surface, and its outer surface serves as a light-emitting surface.

On the other hand, the back plate 13 has a light magnification f (not shown) on its inner surface.
The ik film and the light reflecting film are applied in two layers, upper and lower.

The flat inter-table container 16 has a pair of cold cathodes 178.17b, such as hollow cathode cold cathodes, disposed therein so as to be spaced apart from each other in a direction perpendicular to the direction in which the front plate 12 and the back plate 13 face each other. The discharge space 18 in which discharge is caused between the pair of cold cathodes 178 and 17b is formed in a flat shape.

The pair of cold cathodes 17a, 17b are made of a required mercury alloy, for example, in the shape of a box with a square cross section, and mercury is evaporated from the pair of cold cathodes 17a, 17b by heating, for example, to about 800 to 900°C by high frequency heating. The required amount of mercury is sealed in the airtight container 16.

Further, the pair of cold cathodes 16a and 16b are connected to one end in the axial direction with a pair of Dumet wires 19a and 19b by spot welding or the like.

The pair of Dumet wires 19a and 19b have a diameter of 0, for example.
．． It is formed into a thin wire of 2III&, and by reducing its axial cross-sectional area, the heat transfer rate from the pair of six-shades 117a and 17b during high-frequency heating is reduced.

As shown in FIG. 3, the tips of the Dumet wires 19a and 19b hermetically pass through the frit glass 15 that airtightly connects the back glass 13 to the spacer frame 14, and extend to the outside to connect to an electrical circuit (not shown), etc. It is now connected.

In FIGS. 1 to 3, reference numeral 20 is an exhaust pipe. For example, a dope is connected to this exhaust pipe 20 to exhaust the inside of the flat closed container 16, and the flat closed container 16 is evacuated through this exhaust pipe 20. xenon, krypton, argon,
It is filled with at least one rare gas such as neon or helium.

When mercury is sealed in the flat airtight container 16,
After completing the assembly of the flat fluorescent lamp 11, the container 1 between the flat
After evacuating the inside of the flat fluorescent lamp 11, a pair of cold cathodes 1 are heated from the outside of the flat fluorescent lamp 11 using a high frequency heating coil (not shown).
78.17b is radio-frequency heated to, for example, about 800-900°C.

Then, a pair of cold cathodes 17a made of a mercury alloy.

17b] is evaporated and sealed in the container 16 between the flat tables.

Further, the heat of the pair of cold cathodes 17a and 17b heated to a high temperature is transferred to the pair of Dumets 119a and 19b, respectively.

However, these are the only ones! - Since the thermal conductivity of the wires 19a and 19b is low, the pair of cold cathodes 17a are heated by high frequency heating.
, 17b, when releasing mercury from the cold cathodes 17a, 17b.
It is possible to suppress heat conduction from the sealing portion to the sealing portion, preventing a rise in temperature of the sealing portion, and reducing occurrence of cracks in the sealing portion.

As a result, it is possible to improve the yield during manufacturing of the flat fluorescent lamp 11.

When a predetermined voltage is applied between the pair of Dumet wires 19a and 19b in the flat fluorescent lamp 11 configured as described above, glow discharge occurs between the pair of cold cathodes 17a and 17b, and this glow discharge flattened container 1
The mercury atoms in 6 are excited to generate ultraviolet light, which excites a fluorescent film (not shown) on the front plate 12, is converted into visible light, and is irradiated from the light emitting surface on the outer surface of the front plate 12.

In addition, the ultraviolet rays generated within the flat airtight container 16 are transmitted to the light diffusion film (not shown) of the back plate 13 and the completely destroyed rJ4IIl.
The light is diffusely reflected and guided to the fluorescent film side of the front plate 12, where it is again converted into visible light by the fluorescent film, increasing the luminous efficiency, and visible light is irradiated from the light emitting surface on the outer surface of the front plate 12. Ru.

Therefore, the entire front plate 12 emits light almost uniformly, so there is little unevenness in brightness.

In the above embodiment, a pair of cold cathodes 178.17b and a pair of Schmetz Jl! Although an example in which J19a and 19b are connected has been described, the present invention is not limited to this. For example, instead of Dumet wires 19a and 19b, as shown in FIG. A pair of cold cathodes 1 are connected using the configured foil bodies 30a and 30b as introduction terminals.
It may be connected to 7a and 17b.

In this embodiment as well, each of the foil bodies 30a and 30b is made extremely thin to reduce thermal conductivity.
The heat of the pair of cold cathodes 17a, 17b is transferred to these foil bodies 30a,
30b, and these foil bodies 30a,
It is possible to reduce the temperature difference with the frit glass 15 that seals the glass 30b, reduce the thermal stress applied to the frit glass 15, and reduce the occurrence of cracks therein.

〔Effect of the invention〕

As explained above, in the present invention, each of the pair of cold cathodes is formed of a mercury alloy, and the conductor connected to these cold cathodes is formed of either a thin wire or a foil body. By high-frequency heating, mercury can be evaporated from these cold cathodes, and mercury can be easily sealed in a flat sealed container.

In addition, the heat generated during heating of these cold cathodes is transferred to each introduction terminal, but since each of these introduction terminals is composed of a thin wire or a foil body that reduces heat conduction, a seal is used to seal each of these introduction terminals. It is possible to reduce the temperature difference with the sealing part, reduce thermal stress in the sealing part, and reduce the occurrence of cracks in the sealing part.

Therefore, according to the present invention, it is possible to improve the yield when manufacturing a flat fluorescent lamp.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view showing the overall configuration of an embodiment of the flat fluorescent lamp according to the present invention, FIG. 2 is a plan view showing the assembled state of the embodiment shown in FIG. 4 is a perspective view of essential parts of another embodiment of the present invention, FIG. 5 is an exploded perspective view showing the overall structure of a conventional planar fluorescent lamp, and FIG. FIG. 7 is a front view of FIG. 6, and FIG. 8 is a sectional view taken along the line ■--■ of FIG. 6. 16...Flat closed container, 17a, 17b...Cold cathode, 18...Discharge space, 19a, 19b...Dumet wire (thin wire), 3oa, 30b...Foil body. Applicant's agent - Hisashi Hatano Figure 1 Figure 1

Claims (1)

[Claims] A pair of cold cathodes are arranged to face each other in a discharge space within a flat sealed container, and each part of a pair of introduction terminals connected to each of these cold cathodes is caused to pass through the flat sealed container in an airtight manner and extend to the outside. A planar fluorescent lamp, characterized in that the pair of cold cathodes are each made of a mercury alloy, and each of the introduction terminals is made of either a thin wire with low thermal conductivity or a foil body made of an electrical conductor. shaped fluorescent lamp.