JPH06295707A - Discharge lamp - Google Patents

Abstract

PURPOSE:To shorten radiation time necessary for heating processing to internal electrodes by arranging the unformed parts of a phosphor coat in positions corresponding to the internal electrodes of a bulb. CONSTITUTION:A phosphor coat 2 is formed on an inner wall of a glass bulb 1. Coat separating tools are inserted from both opening ends of the bulb 1, and the unformed parts 3 of the phosphor coat 2 are arranged on the whole periphery or the half periphery in positions corresponding to electrodes 4. An injection optical device 6 is arranged in the vicinity of the unformed parts 3 of the phosphor coat 2 of the bulb 1, and a laser beam generated, for example, by a YAG laser oscillator becomes an infrared beam by the injection optical device, and passes through the unformed parts 3 of the phosphor coat 2, and is radiated to the internal electrodes 4 and 4. The electrodes 4 and 4 radiated by the infrared beam are heated, and decompose a mercury alloy material filled in the electrodes 4 and 4, and generate mercury vapor inside of the bulb 1, and heighten a degree of vacuum inside of the bulb 1 by a getter material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp having a small size and a thin tube, which is optimal as an illumination light source for a liquid crystal display device or the like.
The present invention relates to a discharge lamp most suitable for electrode heat treatment after sealing an internal electrode in a bulb.

[0002]

2. Description of the Related Art A narrow-tube cold cathode discharge lamp used as a back lighting light source for a liquid crystal display device includes a mercury alloy material on a surface or a recess at the end of a bulb having a phosphor coating formed on substantially the entire inner wall surface. The electrode coated or filled with getter material is sealed, the inside of the valve is evacuated, and the internal electrode is heated from the outside of the valve by high frequency induction heating method to decompose the mercury alloy and generate mercury vapor inside the valve. In addition, a getter material has been proposed in which the impure gas in the valve is adsorbed to increase the degree of vacuum (for example, JP-A-4-10445).
No. 2, JP-A-4-149954).

In recent years, along with thinning of liquid crystal display devices, it has been required to make valves thinner, and in order to cope with this thinning, internal electrodes to be installed are inevitably made smaller and thinner. Therefore, in the heat treatment of the internal electrodes by the conventional high frequency induction heating method, the heating efficiency is poor and the heat treatment work is difficult.

Therefore, in recent years, instead of the high frequency induction heating method,
A method of irradiating the electrode with an infrared beam having a peak value in the range of 0.8 to 1.5 μm to heat the electrode has been devised.

[0005]

When the internal electrode is irradiated with an infrared beam that has passed through the bulb for heat treatment, in the cold cathode discharge lamp described in the above-mentioned prior art, the phosphor coating has a phosphor coating on the inner wall surface of the bulb. Since it is formed in almost the entire area of the, the phosphor coating interferes with the transmission of the infrared beam, and the transmittance is about 50.
% Decrease. Due to this reduction in irradiation efficiency, there is a problem that the heat treatment time becomes about twice as long and the production efficiency is reduced to cause a manufacturing defect, and the reduction in energy efficiency is uneconomical.

An object of the present invention is to improve the transmittance of an infrared beam with respect to the internal electrodes of a miniaturized and thinned bulb, thereby shortening the irradiation time required for the heat treatment of the internal electrodes, and improving the production and energy efficiency. It is to provide a discharge lamp that can be improved.

[0007]

In order to achieve the above object, in the discharge lamp of the present invention, a phosphor coating is formed on the inner wall surface of the bulb, and the inner electrode is provided in the discharge lamp. The non-formed part of the phosphor coating is provided at the corresponding position.

Further, the non-formed portion of the phosphor coating is a range corresponding to the length of the internal electrode along the axial direction of the bulb, and the whole or half circumference is along the circumferential direction of the bulb. Is preferred.

[0009]

[Function] Since the fluorescent substance non-forming portion is provided in the bulb near the electrode, the infrared beam can be irradiated to the internal electrode through the transparent glass, and the transmittance of the fluorescent substance coating does not decrease. .

[0010]

Embodiments of the present invention will now be described with reference to the drawings.

In the embodiment shown in FIGS. 1-3,
A phosphor coating 2 is formed on the inner wall of a glass bulb 1 having a tube diameter of 3 dishes and a wall thickness of 0.4 mm. As shown in FIG. 2, the coating stripping tool 7 is inserted from both open ends of the bulb 1 to physically peel off the phosphor coating 2 formed on the inner wall surface of the bulb 1, and the portion where the phosphor coating 2 is not formed. 3 is provided all around the position corresponding to the electrode 4. In addition to the method of peeling the phosphor coating 2 by the physical means, before the phosphor coating 2 is completely dried,
It is also conceivable to eject water or an organic solvent from the nozzle to remove the phosphor coating 2 near the tube end of the bulb 1.

The mounts used are coaxial with the lead wires 5, 5 coaxially with the electrodes 4, 4 in which a mercury alloy powder and a getter powder are filled in a cylindrical body having a diameter smaller than the inner diameter of the bulb 1.
Is attached. Depending on the material of the bulb 1, the material of the lead wires 5 and 5 is, for example, an alloy containing nickel, chromium, or iron as a main component, or a material in which a nickel wire and a dumet wire are connected by welding. The mount is inserted so that the electrode 4 is installed from one end of the bulb 1. The electrode 4 is arranged at a position corresponding to the non-formed portion 3 of the phosphor coating 2. The periphery of one end of the bulb 1 is heated by, for example, a burner or the like to hermetically seal the lead wires 5 and 5. The mount is inserted from the other end of the bulb 1 so that the electrode 4 is installed at a position corresponding to the non-formed portion 3 of the phosphor coating 2. Valve 1
Evacuate from the other end of the chamber and use argon, neon,
A noble gas such as krypton or xenon is sealed in and hermetically sealed by heating as in the above sealing method. The lead wires 5 and 5 extend through the end wall of the bulb 1 in an airtight manner and are led out to the outside.

Next, the heat treatment method for the internal electrodes 4, 4 will be described with reference to FIG. An emission optical device 6 is provided in the vicinity of the non-formation portion 3 of the phosphor coating 2 of the bulb 1. For example, infrared rays generated by a YAG laser oscillator, that is, a laser beam becomes an infrared beam from the emission optical device 6, and the phosphor coating is formed. The internal electrodes 4 and 4 are irradiated with the light through the non-formed portion 3 of 2. The electrodes 4 and 4 irradiated with the infrared beam are heated to about 900 ° C., decompose the mercury alloy material filled in the electrodes 4 and 4, generate mercury vapor inside the bulb 1, and seal it. Impurity gas in the valve 1 is adsorbed by the getter material to raise the vacuum degree to a desired level.

The heat treatment method for the internal electrode is one of fixed position.
The irradiation is not limited to the case where the light is emitted from each of the emission optical devices 6, but the plurality of emission optical devices 6 are arranged at different positions, and the phosphor coating 2
It is efficient to irradiate the internal electrode 4 seen from the non-formation portion 3 with infrared beams from multiple directions. In this case, the electrodes 4 and 4 at both ends of the discharge lamp can be simultaneously irradiated and heated.

In the embodiment shown in FIG. 4, the non-formed portion 3 of the phosphor coating 2 is provided in a semi-peripheral range along the circumferential direction. The other structure is the same as that of the embodiment shown in FIGS.

In this embodiment, the emission optical device 6 is provided near the non-forming portion 3 which is narrower than the non-forming portion 3 of the phosphor coating 2 of the embodiment shown in FIGS. Electrode 4
It irradiates an infrared beam on the.

[0017]

According to the first aspect of the invention, since the non-formed portion of the phosphor coating is provided at the position corresponding to the internal electrode of the bulb,
It is said that the infrared beam passes through this non-formed part without being disturbed by the phosphor coating, and the improvement of the transmittance can improve the production efficiency by reducing the irradiation efficiency and the irradiation time, and further the energy efficiency. effective.

According to the second aspect of the present invention, since the non-formed portion of the phosphor coating is provided in the entire circumference or in the semi-periphery along the circumferential direction, it does not hinder the irradiation of the infrared beam.
In addition, since the non-formation portion is the minimum required range, there is an effect that the brightness of the discharge lamp and the emitted light amount do not decrease.

[Brief description of drawings]

FIG. 1 is a partially cutaway explanatory view of a discharge lamp.

FIG. 2 is an explanatory diagram showing a method of manufacturing a discharge lamp.

FIG. 3 is an explanatory diagram showing a heat treatment method for internal electrodes.

FIG. 4 is a diagram showing another embodiment.

[Explanation of symbols]

 1 Bulb 2 Phosphor coating 3 Non-formation part 4 Electrode 5 Lead wire

Claims (2)

[Claims] 1. A discharge lamp in which a phosphor coating 2 is formed on an inner wall surface of a bulb 1 and internal electrodes 4 and 4 are provided, and the phosphor coating 2 is provided at a position corresponding to the internal electrodes 4 and 4 of the bulb 1. 2. A discharge lamp comprising a non-forming part 3 of FIG. 2. The non-forming part 3 according to claim 1 is a valve 1.
The range according to the length of the internal electrodes (4, 4) along the axial direction of, and the entire circumference or the semi-circumference along the circumferential direction of the bulb (1). Electric light.