JPH0388256A - Fluorescent lamp - Google Patents

Abstract

PURPOSE:To prevent snaking of a positive column for stabilization of flux of light thereof by forming the cross section shape of the bending part in a flat shape while making the maximum diameter of the flat shape longer than the minimum diameter of the flat cross section of a straight part. CONSTITUTION:Cross sections of the straight parts 11a, 12a of respective straight bulbs 11, 12 are formed, for instance, in a flat shape of an elliptic shape, while a discharge path to be passed through by a positive column is formed on the axis of the center of gravity Oa of the flat cross section. On the other hand, a cross section of a connection part 13 is formed, for instance, almost in a fan shape and a long diameter l0 10 is longer set up than a short diameter (s) of the cross section shape of the straight parts 11a, 12a. In this case, electron density of the positive column passed through the respective straight parts 11a, 12a is not heightened at the connection part 13 so that snaking is reduced. In this way, generation provability on snaking is lowered so as to stabilize discharge.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a fluorescent lamp having a bent portion that bends a discharge path into an inverted U-shape or the like, and particularly relates to a fluorescent lamp with an improved bent portion. Regarding.

(Prior Art) As this type of inverted U-shaped fluorescent lamp, those shown in FIGS. 3 and 4 are known, and the fluorescent lamp 1 shown in FIG. Straight valve 2a, 2
The opposing surfaces of the rain upper ends of b are integrally connected via the connecting part 2C, for example, by so-called burner blow-out, etc.
The entire structure is shaped like an inverted U.

The fluorescent lamp 1 has a pair of electrodes 3a at both ends of the inverted U-shape.
, 3b are sealed, and a fluorescent film is attached to the inner peripheral surface thereof, and mercury and rare gas are sealed inside.

On the other hand, the inverted U-shaped fluorescent lamp 4 shown in FIG. is configured in an inverted U shape.

A pair of left and right electrodes ga and 8b are hermetically sealed at the lower ends of both valves 5.6 in the figure.

Further, both bulbs 5.6 have a fluorescent film coated on their inner peripheral surfaces over almost the entire length, and are filled with mercury and a rare gas.

(Problems to be Solved by the Invention) However, in such a conventional fluorescent lamp 1.4, the bulbs 2a, 2b, 5. The cross-sectional shape of 6 is formed into a flat shape such as an ellipse, and furthermore,
Since the inner diameters of these inverted U-shaped bent portions 2d and 4a are smaller than the inner diameters of the respective glass bulbs 2a, 2b, and 5.6, these fluorescent lamps 1 and 4 can be lit in a high current range. Then, in these bent portions 2d and 4a, so-called "snaking" occurs in which the positive column appears to undulate, making the discharge unstable.

When this snaking occurs, there is a significant temporal change in the luminous flux.
Spatial non-uniformity occurs.

The present invention has been made in consideration of the above circumstances, and its object is to provide a fluorescent lamp capable of preventing snaking of the positive column and stabilizing its luminous flux.

[Structure of the invention]

(Means for Solving the Problems) First, the inventors analyzed the mechanism of occurrence of this snaking phenomenon for the fluorescent lamp I.

As a result, it was found that this snaking phenomenon occurs more often in flat bulbs, and that it is more likely to occur in proportion to the impurity concentration at the time of manufacturing the lamp, and approximately in proportion to the square of the electron density of the discharge.

That is, when the discharge electron density increases in the communication portion 2C of the fluorescent lamp 1 shown in FIG. 3, the probability that snaking will occur from this portion increases.

According to experiments conducted by the present inventors, the ratio of the cross-sectional area of the communicating portion 2c to the cross-sectional area of the straight portions 2a and 2b of the bulb 2 having a flat cross-sectional area and the probability of occurrence of snaking have a relationship as shown in the following table.

In Table 1, if the probability of occurrence of snaking is, for example, 5%,
The cross-sectional area ratio of the connecting portion 2c to the straight portions 2a and 2b is 20.
This shows that when 100 % fluorescent lamps 1 were manufactured and they were lit at a constant brightness (for example, electron density 5×10 17 /n'), a snaking phenomenon occurred in 5 fluorescent lamps 1.

Therefore, according to Table 1, snaking can be reduced by increasing the ratio of the cross-sectional area of the communicating portion 2C to the cross-sectional area of the straight portions 2a and 2b.

In addition, in the bent part 2d, the discharge takes the shortest path, so it deviates toward the inner circumference of the bend, making the UV (ultraviolet ray) intensity on the inner circumference higher than on the outer circumference, creating a difference in brightness between the inner and outer circumference. let

Therefore, by slightly deviating the central axis of the bent portion 2d toward the outer circumference of the bend, the positive column is prevented from shifting toward the inner circumference of the bend, and the difference in brightness between the inner and outer circumferences is equalized. can do.

To this end, in the present invention, the cross-sectional area of the communicating portion 2C of the bent portion 2d is expanded, and the center of gravity of the cross-sectional shape is slightly moved toward the outer peripheral portion of the bent portion 2d.

That is, the present invention is configured as follows.

In a fluorescent lamp having a straight portion in which a discharge path is regulated to be straight by a flat bulb, and a bent portion that bends the straight discharge path, the bent portion has a cross-sectional shape formed in a flat shape. Further, it is characterized in that the maximum diameter of the flat shape is longer than the minimum diameter of the flat cross section of the straight portion.

(Function) The bent portion of the fluorescent lamp of the present invention has a flat cross-sectional shape, and the maximum diameter of the flat shape is longer than the minimum diameter of the flat cross-section of the straight portion. The ratio of the cross-sectional area of the bent portion to the cross-sectional area of the straight portion increases.

Therefore, according to the present invention, as is clear from Table 1, it is possible to reduce snaking during discharge at the bent portion, and it is possible to stabilize the luminous flux.

(Example) An example of the present invention will be described below based on FIGS. 1 and 2.

FIG. 2 is a partially cutaway front view showing the overall configuration of an embodiment of the present invention. By connecting the parts together by the connecting part 13,
The entire structure is shaped like an inverted U.

Each straight valve 11.12 has a pair of left and right electrodes 14a, 14b hermetically sealed at its lower end in the figure.
The electrode sealed ends are sealed with pinch seals 15a and 15b.

Both bulbs 11, 12 and the connecting portion 13 have a fluorescent film (not shown) coated on their inner peripheral surfaces almost entirely and over almost their entire length, and mercury and rare gas are sealed inside.

The connecting portion 13 is formed, for example, by blowing out a burner.

This is done by heating and softening the opposing surfaces of the upper ends of both bulbs 11 and 12 in the figure, which are arranged in parallel, using a burner flame, and then connecting the pair of electrodes 14.
Before sealing parts a and 14b, air at a predetermined pressure is blown from the opening at the lower end in the figure to blow out the glass walls of these heat-softened parts.

Both valves 1 are attached to the periphery of the opening opened by this blow-out
1. Cylindrical protruding walls are formed that protrude slightly in opposite directions.

Therefore, these two protruding walls are butted together and fused together, and the fused area and its surrounding area are heated again with a burner flame to anneal, and this heated and softened part is inserted into the mold to form each valve. 11. Molding is carried out by blowing air at a predetermined pressure into 12.

By this molding, the connecting part 13 and the valve 1 before and after it
The thickness of the bent portion 16 of 1.12 can be made almost equal, distortion can be reduced, and mechanical strength can be increased.

In this way, the fluorescent lamp 10 is constructed using a straight bulb 11.1.
A bending portion 16 that bends the straight discharge path formed in the discharge path 2 into a substantially inverted U shape can be integrally formed.

and the straight portions 11a, 12 of each straight valve 11.12.
The cross section of a is formed, for example, in an elliptical flat shape as shown in FIG.
The long axis l, which is the maximum diameter of 11II111, is set to 20 m+a, and the flatness of the short axis/long axis is 0.4.

Further, a discharge path through which a positive column passes is formed at the center of gravity axis Oa of this flat cross section.

On the other hand, as shown in FIG. 1(B), the cross section of the connecting portion 13 is formed, for example, in a substantially fan shape, with the major axis i being the maximum diameter.
o is 10 mm, it is formed with a fan-shaped center angle of 17 degrees,
The major axis to 10 is set longer than the minor axis 58 mm of the cross-sectional shape of the straight portions 11a and 12a.

The cross-sectional area of this connecting portion 13 is the straight portion 11a, 1
It occupies about 70% of the cross-sectional area of 2a, and as is clear from Table 1, the probability of occurrence of snaking in the connecting portion 13 has been reduced to about 0.1% or less.

That is, since the electron density of the positive column that has passed through each of the straight portions 11a and 12a does not increase significantly at the connecting portion 13, it is possible to significantly reduce snaking.

Further, as shown in FIG. 1(B), since the cross-sectional shape of the connecting portion 13 is fan-shaped, the center axis Ob of the connecting portion 13 is aligned with the bent portion 16.
can be eccentrically moved from the inner peripheral part d side to the outer peripheral part U side, and the discharge path of the positive column passing along the center axis Ob can be located almost at the center of gravity of the sector.

For this reason, the positive pillar is bent at the inner circumferential portion d at the connecting portion 13.
By moving closer to the side, the brightness on the inner periphery d side is made higher than on the outer periphery U side, preventing a difference in brightness from occurring between the inner and outer periphery parts d and u, and equalizing the brightness. can.

However, since the deviation of such a discharge path also depends on the pressure of the filled gas and the discharge current, the present invention does not necessarily limit the cross-sectional shape of the connecting portion 13 to a fan shape, but rather the cross-sectional area of the connecting portion 13 is directly It is sufficient that the area ratio is increased so as not to be extremely small with respect to the cross-sectional area of the shaped portions 11a, 12a, and the difference in discharge electron density between the straight portions 11a, 12a and the bent portion 16 is reduced.

〔Effect of the invention〕

As explained above, in the present invention, the cross-sectional shape of the bent portion of the fluorescent lamp is formed into a flat shape, and the maximum diameter of the flat shape is made longer than the minimum diameter of the flat cross-section of the straight portion. The ratio of the cross-sectional area of the bent portion of the discharge path to the cross-sectional area of the straight portion of the discharge path increases.

Therefore, according to the present invention, the difference in discharge electron density between the bent portion and the straight portion can be reduced, the probability of occurrence of snaking in the bent portion can be reduced, and the discharge can be stabilized.

As a result, the luminescence of the fluorescent lamp becomes stable.

[Brief explanation of drawings]

FIG. 1(A) is a cross-sectional view showing a cross section of a straight portion of a discharge path of an embodiment of the fluorescent lamp according to the present invention shown in FIG.
Figure (B) is a cross-sectional view showing the cross section of the connecting part shown in Figure 2, Figure 2 is a partially cutaway front view of an embodiment of the fluorescent lamp according to the present invention, and Figures 3 and 4 are FIG. 1 is a configuration diagram of a conventional inverted U-shaped fluorescent lamp. 10...Fluorescent lamp, 11.12...Bulb, 11
'a, 12a... straight part, 13... connecting part, 16.
...Bending part, Oa, Ob... Central axis, p, IO...
Long axis (maximum diameter), S... short axis (minimum diameter).

Claims (1)

[Claims] In a fluorescent lamp having a straight portion in which a discharge path is regulated to be straight by a flat bulb, and a bent portion that bends the straight discharge path, the bent portion has a cross-sectional shape formed in a flat shape. Further, a fluorescent lamp characterized in that the maximum diameter of the flat shape is longer than the minimum diameter of the flat cross section of the straight portion.