JPS6227497B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a fluorescent lamp, and is particularly suitable for manufacturing a rapid-start type fluorescent lamp. Conventionally, in preheating start type fluorescent lamps,
While evacuating the inside of the bulb, electricity is applied to the filament to decompose the electron radioactive material, and then, before filling in mercury, a high voltage is applied between both filaments to create a faint discharge that disturbs various parts of the tube, such as the phosphor and the bulb. It is known to eliminate impurity gases such as adsorbed gases and decomposed gases of undecomposed electron radioactive substances. However, when this technology is applied to a rapid-start fluorescent lamp that has a transparent conductive film formed on the inner surface of the bulb and a phosphor film on top of this conductive film, the current during a faint discharge flows through the conductive film and this Since the conductive film is destroyed, it is not only difficult to start, but also the mercury sealed in the tube adheres to the destroyed part of the conductive film, adversely affecting the appearance, which is inappropriate.
In particular, rapid start type fluorescent lamps generally use a triple coil filament, which is made by winding a subwire around a main wire and further winding a secondary coil, but the resistance of the subwire is higher than that of the main wire. Therefore, the temperature of the sub-wire is low when energized, and as a result, the decomposition of the electron radioactive material on the side of the sub-wire is insufficient, and impurity gas is difficult to be completely discharged. Compared to optical lamps, it is more likely to cause an abnormal discharge phenomenon called snaking in the early stages of lighting, and it is also more likely to cause blackening caused by the combination of impure gas and mercury after being lit for several thousand hours.
For this purpose as well, it is necessary to eliminate impurity gas by the faint discharge described above before filling the mercury. The present invention was made based on the above circumstances, and includes a method in which gamma alumina and a phosphor are coated on a conductive film formed on the inner surface of a bulb, and a filament coated with an electron radioactive substance is sealed at both ends of the bulb. Then, while evacuating the fluorescent lamp, electricity is applied to the filament to decompose the electron radioactive substance, and a high voltage is applied between the filaments to generate a faint discharge, and this discharge completely decomposes the electron radioactive substance. , the adsorbed impurity gas in various parts of the tube is released, and furthermore, damage to the conductive film is prevented. Hereinafter, the details of the present invention will be explained with reference to Examples. First, one of the fluorescent lamps to which the present invention is applied
An example is shown in FIG. In the figure, 1 is a straight tube type bulb, 2 is a transparent conductive film formed on the inner surface of the bulb 1, 3 is a phosphor coating formed on the conductive film, 4 is a flare stem that closes the end face of the bulb 1, 5,
5 is a pair of lead wires extending through the stem 4 and into the valve 1; 6 is a pair of lead wires 5, 5;
A triple coil filament is mounted between the tips of the filament 6, 7 is an electron radioactive material coated on the filament 6, and 8 is an exhaust pipe provided on the stem 4. The phosphor coating 3 is formed by adhering to the phosphor a mixture of gamma alumina in an amount of 0.1 to 1 wt% of the weight of the phosphor. Next, the exhaust sealing process for this fluorescent lamp will be summarized using the exhaust schedule shown in the second diagram.
A number of heads are arranged in a ring around the edge of the turntable 10, and a first position 11 of the heads
The lamp is attached at the second position 12, the exhaust pipe 8 is connected to the exhaust system, and the position belonging to the range 13 is located in the heating furnace 14, which is heated while being evacuated to eliminate the adsorbed impurity gas. Next, at position 16 belonging to range 15, the lead wires 5, 5 contact the writing rails 17, 17 to energize the filament 6, and the electron radioactive substance 7 is decomposed and activated by the heat, and is emitted at this time. The cracked gas is sufficiently exhausted. And position 18
In each filament 6, 6, approximately
While passing a heating current of 0.55A, another rail (not shown) is used to connect the filaments 6 and 6 at both ends.
A no-load voltage of 700V is applied to generate a faint discharge, and the ion bombardment of this discharge completely decomposes the electron radioactive material 7, and also removes the decomposed electron radioactive material and phosphor coating 3 inside the tube. Impure gas adsorbed on the member is also released and exhausted at the same time. Then, in position 19, mercury is sealed,
Next, starting gas is charged at position 20, and exhaust pipe 8 is sealed at position 21.
At position 22, the sealed lamp is taken out. Therefore, the phosphor coating 3 made of a phosphor mixed with alumina easily causes a weak discharge even at a no-load voltage of approximately 500 to 600 V, which is 100 to 200 V lower than that in a case that does not contain alumina. . The higher the alumina mixing ratio, the greater the effect, but γ
When the amount of alumina mixed is about 2% of the weight of the phosphor, another problem arises, which is that the luminous flux decreases significantly during the life, which is not preferable. According to experiments, the preferred range of the amount of gamma alumina mixed is 0.1 to 1.0% of the phosphor weight. In this way, by mixing γ alumina into the phosphor film 3, it has become possible to lower the no-load voltage, and as a result, the destruction of the conductive film 2 can be reduced to the extent that it does not pose a problem in practice. . In other words, the branch current of the discharge current flowing into the conductive film 2 could be suppressed to the extent that destruction of the conductive film 2 could be prevented. Therefore, it is thought that the function of γ alumina is to increase the degree of vacuum in the lamp through getter action, thereby making it easier for the discharge current to flow through the lamp space. In other words, when a getter agent is mixed and applied to the phosphor, this getter effect is caused by the impurity gas in the discharge space of the lamp during the normal exhaust process, that is, the process of heating the lamp, exhausting the lamp, and performing natural cooling. The purpose is to absorb and facilitate discharge. However, there are many different types of sticklers, but
The finer the particle size, the better, the less likely it is to combine with mercury and amalgam, and the performance of which remains unchanged until the end of its life, and γ alumina nearly satisfies these conditions. In addition, in tests in which the particle size of γ alumina was varied, particles with an average particle size of 5 to 50 mμ were most effective in lowering the discharge current. Next, using a rapid start type 40W fluorescent lamp as an example, the abnormal discharge occurrence rate and tube wall blackening occurrence rate were compared between the above-mentioned lamp of this example and the comparative example. The results are shown in the table below.

[Table] In this way, according to the method of this example, it is possible to decompose undecomposed electron radioactive materials by low-light discharge and eliminate adsorbed impurity gases, and prevent abnormal discharges caused by residual impurity gases from occurring on the tube wall after the lamp is completed. There is little blackening, and there is little damage to the conductive film due to the action of γ alumina, so there is little deterioration in lighting appearance due to increased starting voltage or mercury adhesion. Note that in the above embodiment, γ alumina is mixed into a phosphor to form a phosphor film, but the present invention is not limited to this. For example, a γ alumina film is formed on a conductive film, and γ alumina is added thereto. A phosphor film may be formed on the conductive film, or a γ film may be formed on the conductive film.
An alumina-free phosphor coating may be formed and gamma alumina deposited thereon. As described above, the method for manufacturing a fluorescent lamp of the present invention includes coating gamma alumina and a phosphor on a conductive film formed on the inner surface of a bulb, and sealing a filament coated with an electron radioactive substance on both ends of the bulb. While evacuating the fluorescent lamp, electricity is applied to the filament to decompose the electron radioactive substance, and before filling in mercury, a high voltage is applied between the filaments at both ends to generate a faint discharge and eliminate impurity gas inside the tube. Therefore, there is less abnormal discharge and blackening of the tube wall, and there is less damage to the conductive coating, so there is an advantage that there is less increase in starting voltage and less deterioration in lighting appearance due to mercury adhesion.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an example of a lamp to which the fluorescent lamp manufacturing method of the present invention is applied, and FIG. 2 is an explanatory diagram showing the manufacturing method. DESCRIPTION OF SYMBOLS 1... Bulb, 2... Conductive film, 3... Phosphor coating, 6... Filament, 7... Electron radioactive material.

Claims (1)

[Claims] 1. A fluorescent lamp comprising gamma alumina and a phosphor coated on a conductive film formed on the inner surface of the bulb, and a filament coated with an electron radioactive substance at both ends of the bulb is evacuated. The method is characterized in that, while electricity is applied to the filament to decompose the electron radioactive substance, a high voltage is applied between the filaments at both ends to generate a faint discharge and eliminate impurity gas in the tube before filling with mercury. Method of manufacturing light lamps. 2. A method for manufacturing a fluorescent lamp according to claim 1, characterized in that gamma alumina is mixed and deposited on the phosphor in an amount of 0.1% to 1% of the weight of the phosphor.