JPS5842946B2 - fluorescent lamp - Google Patents

Description

[Detailed description of the invention] This invention relates to fluorescent lamps.

The structure of conventional fluorescent lamps and their shortcomings are explained first.
This will be explained based on the figure and FIG.

That is, in a conventional fluorescent lamp consisting of a 40W, 32mrrt tube, for example, as shown in FIG. A mount in which a filament 5 is pinched in 4 is sealed to both ends of the glass tube 1.

The filament 5 is coated with a suitable electron emissive material.

The other end of the lead-in wire 4 is connected to a base pin 6.

A predetermined amount of mercury and an inert gas are sealed in the discharge space 7 inside the tube.

In addition, a glass tube 1 is installed to assist in starting the fluorescent lamp.
There is also a type in which a metal transparent conductive film (hereinafter referred to as NESA film) 8 is applied between the phosphor and the phosphor 2.

The basic alternating current lighting operation of this fluorescent lamp is performed as follows.

(1) First, a preheating current is applied to the filament to uniformly heat each part of the filament.

(2) If the filament voltage is different from the ionization voltage of the filled gas, the filled gas is ionized.

(3) The generated ions and electrons alternately flow into both ends of the filament.

(4) Due to this inflow, both end portions of the filament become incandescent, producing a bright spot and producing a negative glow around this portion, lowering the temperature of the middle portion of the filament.

(5) This glow generation reduces the cathode drop, making it easier to light up.

(6) At this time, when the preheating circuit is opened, the light is turned on by the inductance kick of the ballast, creating a bright spot on the power supply side that becomes a source of thermionic emission, and sustaining the discharge.

(The above is the Illuminating Engineering Society of Japan vol. 42 Arashi 11
(From Kizaki, P. 15-P. 16) Such fluorescent lamps have the following drawbacks.

(1) The tube wall temperature of this fluorescent lamp during lighting is 2
In a room at 5℃, the distribution is as shown in Figure 2, and the bright spot temperature of the filament during lamp lighting is approximately 100℃.
It has reached 0℃.

On the other hand, since the ambient temperature of the lamp is low, around room temperature, there is a large temperature difference, and heat mainly escapes to the tube wall around the filament by radiation.

Therefore, as shown in FIG. 2, the temperature distribution on the tube wall is the highest at the filament position, and gradually decreases as it approaches the center of the tube, becoming almost uniform at a position several tens of α away from the tube end.

Since the tube wall temperature shows the above distribution, the mercury sealed in the lamp concentrates and precipitates in part A, which is relatively low temperature and has a large temperature difference (temperature gradient), and as shown in Figure 2. This causes stains due to mercury precipitation as shown in the figure, which deteriorates the appearance of the lamp when it is lit.

(2) In a rapid-start type fluorescent lamp in which a Nesa film is applied to the inner surface of the fluorescent lamp as a starting aid, the dog portion of the potential distribution inside the tube while the lamp is lit corresponds to the stain 9 due to mercury precipitation mentioned above. As a result, a slight discharge occurs between the mercury grains and the Nesa film through the phosphor, resulting in dielectric breakdown of the phosphor (so-called pock phenomenon).

(3) The bright spot temperature of the filament maintains an equilibrium state of approximately 1000℃ after compensating for heat loss due to radiation, and the cathode drop voltage is equal to the value including the compensation for heat loss. It has become.

In other words, cathode drop voltage = (voltage required for discharge) + (voltage to compensate for heat loss).

On the other hand, power consumption in the cathode section is expressed as (cathode drop voltage) x (lamp current), but this power is not useful for light output.

Therefore, the greater the power consumption at the electrodes, the lower the efficiency of the lamp.

Conventionally, the lamp efficiency is reduced by the cathode drop voltage valve to compensate for this heat loss.

As described above, the temperature distribution of the tube wall of the glass tube 1 causes contamination 9 of the tube wall due to mercury and a decrease in lamp efficiency.

Therefore, an object of the present invention is to control the temperature distribution of the tube wall of a glass tube to prevent mercury contamination;
Another object of the present invention is to provide a highly efficient fluorescent lamp.

An embodiment of this invention will be explained based on FIGS. 3 to 6.

First, FIGS. 3A and 3B each show the first embodiment, and 1 is for 40W with a diameter of 32mm and a length of 120mm.
The phosphor 2 is coated on the inner surface of a 0 mm glass tube.

A mount in which a filament 5 is pinched onto an introduction wire 4 embedded in a glass stem 3 is sealed to both ends of this glass tube 1.

The filament 5 is coated with a suitable electron emissive material.

The other end of the lead-in wire 4 is connected to a base pin 6.

An inner tube 10 made of ultraviolet-transparent glass is placed between the glass tube 1 and filament 5 of this lamp, and the inner tube 10 is coated with an infrared reflective film 11 such as indium oxide In2O3>tin oxide 5n02, and the glass stem 3 is It is fixed by an embedded support fitting 12.

This inner tube 10 has a diameter of 2571t71L, and starts from the lower end of the glass stem 3, several minutes beyond the tip of the filament 5 (in other words, in the discharge space, near the boundary between the Faraday dark area and the positive column, 7CrIL from the end of the glass tube). ) has been inserted.

Further, a predetermined amount of mercury and an inert gas are sealed in the discharge space 7, and a Nesa film 8 is applied to form a rabbit start type.

Note that this inner tube 10 may have a structure in which it is directly bonded to the mount as shown in FIG. 3B.

Further, FIGS. 4A and 4B each show a second embodiment, in which the inner tube 10' made of ultraviolet transmitting glass coated with an infrared reflective film 11 on the inner surface is further extended to 25 cr.
The IL is inserted into the positive column from the end of the tube to the central part off the ramp, and has the same structure as the first embodiment in other respects.

Note that the inner tube 10' is supported by the support fitting 1 as shown in Fig. 4A.
2, or may be directly bonded to the mount as shown in FIG.

Furthermore, FIG. 5 shows a third embodiment, which has a double-tube structure in which an inner tube 10'' made of ultraviolet-transmitting glass whose inner surface is coated with an infrared reflective film 11 is inserted along the entire length of the lamp. The second embodiment has the same structure as the first embodiment.

This inner tube 10 is fixed from both ends by support fittings 12 embedded in the glass stem 3.

Each of the fluorescent lamps configured in this manner performs lighting operation exactly the same as a conventional fluorescent lamp.

During lighting, ultraviolet light emitted by mercury atoms excited by accelerated electrons in the fluorescent lamp tube passes through the inner tubes 10 and 10' made of ultraviolet-transmitting glass.

The phosphor 2 deposited on the glass tube 1 through 1σ'
is excited, and visible light is emitted from the excited phosphor 2.

On the other hand, the radiant heat from the filament 5 is
, 10' by the infrared reflective film 11 on the inner tubes 10, 10'.
, 10'', the amount of heat rays escaping to the tube wall of the glass tube 1 of the fluorescent lamp decreases, and the temperature of the tube wall decreases.

Since the heat loss of the filament is reflected back in the same way, the power consumption of the electrodes to compensate for this heat loss is reduced.

As a result, the following effects occur.

(1) Tube wall temperature distribution Regarding Examples 1 to 3, the tube wall temperature distribution during lighting in a room at 25°C is gradual over the entire length of the glass tube 1, as shown by curves I to ■ in Fig. 6, respectively. Therefore, large temperature differences (like the conventional example shown in Figure 2)
temperature gradient) has disappeared.

In particular, the tube ends are the coldest.

Furthermore, in the case of Example 3 (curve ■), the temperature at the central portion of the lamp is several degrees lower than that of the conventional lamp.

Therefore, the contamination 9 due to mercury precipitation is most concentrated at the end of the tube, and then very sparsely and thinly deposited over a fairly wide area near the center of the lamp.

Therefore, the appearance of blackening due to mercury precipitation has become completely unnoticeable.

Incidentally, since the luminance at the end of the tube is originally low (=dark), dirt is noticeable<<, but there is no problem in appearance due to mercury precipitation.

(2) Pock phenomenon In rabbit-start fluorescent lamps with Nesa film, a large part of the potential distribution inside the tube during lamp operation (
Since almost no mercury particles were deposited in the area (10 to 20 CrrL from the tube end), mercury particles were not deposited through the phosphor.
There was no chance of slight discharge between the Nesa films, and the pock phenomenon could be prevented.

(3) Heat loss in the filament As the heat loss is reflected back to the filament by the infrared reflective film on the inner surface of the inner tube, the cathode drop voltage decreases by the voltage valve used to compensate for the heat loss, and the voltage drop at the electrode decreases by that amount. Lamp efficiency increased due to reduced power consumption.

(4) Other effects (a) Preventing blackening at the end of the lamp tube due to scattering of electrode material Since a transparent inner tube is placed around the filament, it is no longer possible to prevent blackening of the end of the lamp tube due to scattering of electrode material as in the past. It has the same effect as a metal ring.

Moreover, since the inner tube is transparent, there is no shadow like that of a conventional metal ring (conventionally, the 40W class uses a metal ring, so the luminous flux fell by about 301 m).

(b) Energy-saving effect Since the fluorescent lamp has a double-tube structure (especially in Examples 2 and 3, the inner tube is inserted into the positive column), it is possible to substantially reduce the lamp tube diameter and achieve the same effect. have

As a result, the lamp current is reduced and the ballast power loss is reduced accordingly.

The table below shows the reduction values.

As described above, in the fluorescent lamp of the present invention, an inner tube made of ultraviolet-transmitting glass with an infrared reflective film formed on the inner surface is interposed in the space between the glass tube and the electrode, so that heat is reflected within the inner tube. As a result, the temperature of the tube wall decreases and its distribution becomes gentler, and as a result, the precipitation of mercury is suppressed, and the places where a lot of mercury is precipitated become near the ends of the tube where the brightness is low, making it less noticeable and the pock phenomenon also prevented. Furthermore, it has the effect that heat loss of the filament is reduced and efficiency can be increased.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway side view of a conventional fluorescent lamp, Fig. 2 is an explanatory diagram of the condition of the tube wall and its temperature distribution during use, and Figs. FIG. 6 is a partially cutaway side view of the fluorescent lamp of the third embodiment, and is an explanatory diagram of the tube wall condition and its temperature distribution during use. 1... Glass tube, 5... Filament (electrode), 10.10', 10''... Inner tube.

Claims (1)

[Scope of Claims] 1. A fluorescent lamp in which an inner tube made of ultraviolet-transmitting glass with an infrared reflective film formed on the inner surface is interposed in the space between the glass tube and the electrode. 2. A fluorescent lamp according to claim 1, in which the inner tube is arranged near the end of the glass tube. 3. A patent in which the inner tube extends from the end of the glass tube to near the center of the glass tube. A fluorescent lamp according to claim 1. 4. A fluorescent lamp according to claim 1, wherein the inner tube extends over the entire length of the glass tube.