JPH0461740A - Life notifying method for fluorescent discharge lamp - Google Patents

Abstract

PURPOSE:To construct a device concerned in a small size and suppress the cost by forming a pair of hot cathodes of a fluorescent discharge lamp provided with different lifetimes, and installing a thermosensitive element only at the tube end side fitted with that of the hot cathodes which is set on the shorter lifetime side. CONSTITUTION:A fluorescent discharge lamp 1 is equipped with a pair of hot cathodes 2. 3, which are provided with different lifetimes, and a temp. fuse 4 as a thermosensitive element is installed only on the side with that of the hot cathodes 2 which is formed with shorter lifetime. Accordingly the lifetime of the lamp 1 depends upon the hot cathode 2 set with shorter lifetime and can be notified certainly through provision of thermosensitive element on that of the tube ends where this hot cathode 2 is installed. Thereby the number of thermosensitive elements can be decreased to the half to lead to constructing of the device in small size and suppressing the cost.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to fluorescent discharge lamps that are used inside, for example, automobiles or portable equipment.

[Conventional technology]

FIG. 3 shows an example of this type of conventional lifespan notification method, in which tube ends at both ends of the fluorescent discharge lamp 91 are placed opposite to each of the hot cathodes 92 and 93 of the fluorescent discharge lamp 91. Temperature fuses 94 and 95 are provided, and the temperature fuses 94 and 95 are blown out by utilizing the phenomenon that the temperature at the end of the tube increases at the end of the life of the fluorescent discharge lamp 91, The output will notify you when it is time to replace it.

[Problem to be solved by the invention]

However, with the conventional notification method described above, it is impossible to predict which side of the hot cathode 92, 93 will experience a temperature rise faster due to manufacturing variations, etc. Therefore, for example, when configured to detect only one side of the hot cathode 92, 93, If a temperature rise occurs early on the non-detection side, this temperature rise will cause burnout of equipment, etc. Therefore, a configuration in which temperature fuses 94 and 95 are provided at both tube ends as described above is adopted. This has become unavoidable, causing problems that increase the size of the device and increase costs, and it has been a challenge to solve this problem.

[Means to solve the problem]

As a specific means for solving the above-mentioned conventional problems, the present invention provides a lifespan notification method for a fluorescent discharge lamp in which a heat-sensitive element is arranged at the end of the tube and the lifespan is notified by the output of the heat-sensitive element. A fluorescent discharge lamp characterized in that a pair of hot cathodes of the discharge lamp are formed with different lifespans, and the heat-sensitive element is disposed only on the tube end side where the hot cathode set to have a short life is disposed. The above-mentioned conventional problems are solved by providing a lifespan notification method.

【Example】

Next, the present invention will be explained in detail based on an embodiment shown in the drawings. The reference numeral 1 in FIG. 1 is a fluorescent discharge lamp, and this fluorescent discharge lamp 1 is similar to the conventional example in that it is provided with a pair of hot cathodes 2.3. Hot cathode 2
The hot cathode 3 and the hot cathode 3 are formed with different lifespans, and a temperature fuse 4, which is a heat-sensitive element, is disposed only on the side of the hot cathode 2, which is formed with a shorter life. Next, means for providing a reliable difference in life between the hot cathode 2 and the hot cathode 3 will be explained. What is shown in FIG. 2 is a graph showing the results of experiments conducted by the inventor to realize the present invention.
The curve shown by represents the amount of emitter such as Bas 5r1Ca applied to the hot cathode 2 (or hot cathode 3), and
This figure shows the relationship with the lifespan of the fluorescent discharge lamp 1. According to the figure, for example, by applying approximately 0.5-g of coating, the fluorescent discharge lamp 1 can have a lifespan of approximately 15,000 hours. It has been shown that the fluorescent discharge lamp 1 can be expected to have a longer lifespan by further increasing the amount of the emitter applied. Based on the above experimental results, in the present invention, the hot cathode 2 side, which is the one of the pair, is coated with enough emitter to guarantee the required specified lifespan, and the other side, the hot cathode 3 side, is coated with enough emitter to guarantee the required specified lifespan. is consciously applied to the hot cathode 2 by applying more emitters.
and the hot cathode 3. Due to this life difference, the life of the fluorescent discharge lamp 1 depends on the hot cathode 2, which is set to be shorter. The lifespan can be reliably notified simply by providing it at the end of the tube on the side where the hot cathode 2 is disposed. In addition, in actual implementation, it is difficult to adjust the application amount in milligram units as explained above.
If the surface areas of the hot cathode 2 and the hot cathode 3 are formed to be different, and the coating is applied by, for example, a depping method, each can be formed so that a prescribed amount of emitter is deposited on each. The invention is extremely easy to implement.

【Effect of the invention】

As explained above, according to the present invention, a pair of hot cathodes of a fluorescent discharge lamp are formed with different lifespans, so that the lifespan of the fluorescent discharge lamp is determined by one of the hot cathodes. By placing it on the hot cathode side, which determines the lifespan, it is possible to reliably notify, and the number of heat-sensitive elements can be halved, resulting in an excellent effect on miniaturization and cost reduction of this type of notification method. be.

[Brief explanation of drawings]

Fig. 1 is a schematic wiring diagram showing an embodiment of the method for notifying the life of a fluorescent discharge lamp according to the present invention, and Fig. 2 shows the relationship between the amount of emitter coating and the life of the fluorescent discharge lamp in the same embodiment. graph,
FIG. 3 is a schematic wiring diagram showing a conventional example. 1---------Fluorescent discharge lamp 2.3-----
---One hot cathode 4--Temperature fuse

Claims (2)

[Claims] (1) A lifespan notification method for a fluorescent discharge lamp in which a heat-sensitive element is arranged at the end of the tube and the lifespan is announced based on the output of the heat-sensitive element, in which a pair of hot cathodes of the fluorescent discharge lamp are formed with different lifespans, A method for notifying the life of a fluorescent discharge lamp, characterized in that the heat-sensitive element is disposed only on the tube end side where the hot cathode, which is set to have a short life, is disposed. (2) The fluorescent discharge lamp according to claim (1), wherein the life of the hot cathode is set by providing a difference in the amount of emitter applied to each hot cathode. Lifespan notification method.