JPS6314462B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a low-pressure mercury vapor discharge lamp (hereinafter abbreviated as low-pressure discharge lamp), such as a fluorescent lamp.

Fluorescent lamps, which are a type of low-pressure discharge lamp, are conventionally
As shown in FIG. 1, a stem 4 supporting a lead wire 3 is sealed inside both ends of a glass tube 2 whose inner surface is coated with a phosphor 1, and an electron radioactive material is attached to the tip of the lead wire 3. A filament electrode 5 coated with is supported. Furthermore, caps 7 each having two cap pins 6 are sealed to the outside of both ends of the glass tube 2 . The discharge space 8 within the glass tube 2 is filled with mercury particles and a predetermined amount of diluent such as argon gas after the evacuation and vacuum processes.

To explain the operation of such a conventional fluorescent lamp,
Accelerated electrons inside the tube collide with mercury atoms to excite them, and when the mercury atoms in this excited state return to a stable ground state, they emit mainly ultraviolet rays of 254 nm. This ultraviolet light is irradiated onto the phosphor 1,
The fluorescent lamp emits light by emitting visible light from the fluorescent body 1.

To explain the above in more detail, when _an electron with an energy of 4.89eV or more among the electrons in the tube collides with a mercury atom, the mercury atom is excited to the ^{6 3 P} ₁ excitation level; When a certain mercury atom returns to its ground state, it emits 254 nm ultraviolet light. Even if an electron with an energy of 4.89eV or less collides with a mercury atom, no change occurs in the internal state of the mercury atom, the energy of the electron only accelerates the mercury atom, and the energy lost by the electron becomes a loss. .

Therefore, in general, in order to improve the luminous efficiency of a fluorescent lamp, it is more advantageous to have as many high-speed electrons as 4.89 eV or higher.

Generally, in a low-pressure discharge lamp, the charge within the tube diffuses to the tube wall, where it recombines with ions and is lost. To compensate for this lost charge, some of the accelerated electrons (high-speed electrons with energy greater than 10.43 eV) collide with mercury atoms inside the tube, ionizing the mercury and creating a new charge. The newly created electrons have low energy, and the high-speed electrons that collide with each other also lose their speed. These slowed-down electrons are again accelerated by the electric field to become high-speed electrons. Therefore, the electrons that reach the tube wall do not contribute to light emission and are completely lost.

In order to improve this drawback, the applicant has developed the second
We proposed a low-pressure discharge lamp as shown in the figure. The structure different from the conventional fluorescent lamp shown in FIG. 1 is that a mesh-shaped conductive cylinder 9 is provided across the discharge space 8 in the tube, that is, approximately between the two electrodes 5, 5, and the cylinder 9 is lowered from the cathode side potential. Furthermore, the cylindrical body 9 is made of a conductive material such as stainless steel, and the size of the mesh is 8 ^M to 14 ^M. (14 ^M indicates the number of sieves contained in 1 square inch is 14).

The case where a fluorescent lamp having such a structure is used in a circuit as shown in FIG. 3 will be explained. The conductive cylindrical body ₉ is connected to the _second ,
Since the third AC power sources E ₂ and E ₃ are connected to the main power source E ₁ with the polarities as shown in the figure, when the fluorescent lamp is lit by the ballast L and glow starter G, the conductive The cylindrical body 9 always has a more negative potential than the cathode side potential. Therefore, the electrons within the tube that try to diffuse toward the tube wall are repelled by the negatively biased conductive cylinder 9 and are eventually confined within the tube. Therefore, it is now possible to confine high-speed electrons with an energy of 4.89 eV or more, which is effective for fluorescent lamp light emission, inside the tube, eliminating the loss of high-speed electrons that are lost at the tube wall and no longer contribute to light emission, as in the past. Since this can be prevented, the luminous efficiency of the fluorescent lamp can be improved.

However, in such an improved fluorescent lamp, a part of the ultraviolet rays generated inside the tube is blocked by the newly installed conductive cylinder 9 inside the tube, reducing the amount of ultraviolet rays hitting the phosphor 1 and reducing the luminous efficiency. It was found that the improvement effect was reduced. In addition, since the conductive cylinder 9 is inside the tube, the terminal electrically connected to the cylinder 9 must be placed outside the lamp in order to connect the power supplies E ₂ and E ₃ to bring the cylinder 9 to a negative potential. Therefore, there was a problem in that either the stem 4 had to have a different shape from the conventional one or the glass tube 2 had to have a special shape.

The present invention has been made to improve the above-mentioned drawbacks, and an object of the present invention is to form a transparent conductive coating on the outer surface of a glass tube of a low-pressure discharge lamp such as a fluorescent lamp, and apply the conductive coating to the cathode. By electrically connecting the potential to be more negative than the side potential, an electric field is generated from inside the tube toward the conductive coating, and due to the presence of this electric field, high-speed electrons that would be lost at the tube wall are trapped inside the tube, and the mercury By increasing the chances of collision with atoms, which effectively contributes to light emission, it improves the luminous efficiency of the lamp, and by forming a transparent conductive coating, the efficiently emitted light is not lost, and the conductive coating is made of glass. The object of the present invention is to provide a low-pressure discharge lamp with a simple structure by forming the lamp on the outer surface of the tube.

Hereinafter, the present invention will be explained in detail based on Examples. Fourth
The figure is a partially sectional front view showing one embodiment of the present invention.The structure is different from the conventional fluorescent lamp shown in FIG. Other configurations are the same except that a coating 10 is applied and electrical connection terminals (not shown) are provided at appropriate locations on the conductive coating 10, so the same reference numerals as those shown in FIG. 1 are used. In particular, the explanation will be omitted.

Next, the operation and effects of the fluorescent lamp having such a configuration will be explained. When the electrically conductive film 10 is connected to the terminal 11 and made to have a more negative potential than the cathode side potential using a circuit configuration as shown in FIG. 6, the positive column plasma becomes positive and the electrically conductive film 10 becomes negative during discharge. , an electric field is generated from the positive column plasma toward the conductive coating 10. When an insulator is placed in an electric field, dielectric polarization occurs because the insulator is a dielectric. Therefore, it will be easily understood that the glass tube 2, which is an insulator located between the positive column plasma and the conductive film 10, causes dielectric polarization as shown in FIG.
In addition, in FIG. 5, arrow E indicates the direction of the electric field,
+ indicates a positive potential, and - indicates a negative potential. Due to this dielectric polarization, the inner surface of the glass tube 2 of the fluorescent lamp has a negative potential. Then, the electrons trying to diffuse toward the tube wall as described above generate an electrical repulsion force between them and the tube wall, which is at a negative potential, and are confined within the tube. Therefore, it is effective for emitting light from fluorescent lamps.
It is now possible to confine high-speed electrons with energy of 4.89 eV or more inside the tube, and it is possible to prevent the loss of high-speed electrons at the tube wall and no longer contribute to light emission, which improves the luminous efficiency of fluorescent lamps. Improvements can be made. As an example, when the present invention was applied to a 10W fluorescent lamp, the luminous efficiency was improved by about 10%. Since the conductive coating 10 is transparent, the emitted light can be used efficiently as described above without loss. Furthermore, since the conductive coating 10 is provided on the outer peripheral surface of the glass tube 2, the coating 10 can be used efficiently. A fluorescent lamp with a simple terminal configuration for electrical connection can be provided.

[Brief explanation of the drawing]

1 and 2 are partially sectional front views showing conventional fluorescent lamps, FIG. 3 is a circuit diagram for lighting the fluorescent lamp shown in FIG. 2, and FIG. 4 is a diagram showing one example of the present invention. FIG. 5 is an enlarged sectional view of the same glass tube portion as above, and FIG. 6 is a circuit diagram for lighting the fluorescent lamp according to the present invention. 1... Fluorescent material, 2... Glass tube, 5... Electrode,
10... Conductive film.

Claims (1)

[Claims] 1 A low-pressure mercury vapor discharge lamp equipped with electrodes facing each other at both ends of a glass tube whose inner surface is coated with a phosphor, wherein a transparent conductive coating is formed on the outer surface of the glass tube, and the conductive coating is coated with the A low-pressure mercury vapor discharge lamp that is biased to a more negative potential than the cathode side potential of both electrodes.