JPH0638331B2 - Low pressure discharge lamp - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a low pressure discharge lamp having a single base structure.

[Background Art] As a lamp suitable for use in a large display, a decorative display, etc., a fluorescent lamp 2 which is lit by using a high frequency inverter 1 as shown in FIG. 18 and a CRT single tube 3 as shown in FIG. There is a fluorescent lamp 2 in Fig. 1
Since it originally has electrodes at both ends and forcibly bends what should be a double-ended structure, it is difficult to reduce the size because it is complicated and expensive, and it is impossible and wasteful for the desired light distribution. Further, since the discharge is the same as that of the conventional fluorescent lamp, there is a drawback that the starting voltage and the discharge sustaining voltage are high.

Further, in the conventional example of FIG. 19, a high voltage anode 5 and a cathode 6
It is necessary to apply a high voltage between the
However, the structure is complicated and the cost is high, and the luminous efficiency from the surface of the phosphor 4 is still low.

Further, a small electrode has a problem that the response is poor due to heat radiation, and the efficiency is low and the life is short.

[Object of the Invention] The present invention has been made in view of the above-mentioned problems, and the object thereof is that the structure is essentially one-sided, and that it is simple in structure and can be driven with a low power supply voltage. (EN) Provided is a low-pressure discharge lamp capable of emitting light with high brightness.

DISCLOSURE OF THE INVENTION According to the present invention, an electron emission cathode and a mesh-shaped or ring-shaped apertured anode are arranged close to each other at one end in a tubular body, and the distance between the anode and the cathode is sufficiently smaller than the entire length of the tubular body. The anode side of the anode is set to a sufficiently wide space and the space inside the tube is filled with a small amount of light-emitting gas so that the pressure is a few mmTorr during operation, and a negative resistance discharge is generated between the anode and cathode. The first invention is a low-pressure discharge lamp which is characterized in that a cathode for electron emission and a mesh-shaped or ring-shaped opening anode are arranged in close proximity to each other at one end inside the tube, and the cathode between the anode and the cathode is arranged between them. The distance is set to be sufficiently smaller than the entire length of the tube, the space on the side opposite to the cathode of the anode is set sufficiently wide, and a small amount of light emitting gas is enclosed in the tube so that the pressure is several mmTorr during operation. A static magnetic field is applied outside one end of the tube body on the cathode side in a direction substantially parallel to the electric field between the cathode and the anode, and negative resistance discharge is caused between the anode and the cathode. In addition to the second invention of the low-pressure discharge lamp, the cathode for electron emission and the mesh-shaped or ring-shaped opening anode are arranged close to each other at one end in the tube, and the distance between the anode and the cathode is compared with the entire length of the tube. And the anode side of the cathode side is set to be sufficiently wide, and a small amount of light emission gas is sealed in the tube body so that the pressure is several mm Torr during operation. A low-pressure discharge lamp, characterized in that magnets are arranged outside the other end of the tube on the opposite side so that the polarities are opposite to each other, and a negative resistance discharge is generated between the anode and the cathode. To do A description will be given below with reference to examples.

Embodiment 1 FIG. 1 shows a basic present embodiment of the first invention, and in this embodiment, a light-transmissive tubular body 8 having a short outer shape and a large columnar shape is used, and the inner circumference of the tubular body 8 is used. The inner surface and the inner surface are coated with a phosphor 9, and a light-emitting gas 10 such as mercury is used for several mmT.
A cathode 11 and an anode 12 are arranged close to each other at the bottom, which is one end of the tubular body 8, by enclosing about orr.

The cathode 11 is a thermionic electron cathode that emits electrons and is directly heated (or indirectly heated). Here, a cathode that is strong against vacuum evaporation such as an impregnated cathode or a BI (Barium Integrated) cathode is most suitable because it is closer to a vacuum as compared with an ordinary fluorescent lamp because there is substantially no rare gas.

As the anode 12, a mesh-shaped (or ring-shaped) open-type anode is used.
The distance l with 1 is selected to have a relational relationship with the mean free path λ of the electron, and the relation is set to several λ ≧ l ≧ several 1 λ 2.

Then, the cathode 11 is heated by using the DC power supply 13, and a voltage is applied to the anode 12 through the stabilizing resistor 14 to reach a voltage (10V or more) at which discharge occurs between the anode 12 and the cathode 11. Then, the space charge in the vicinity of the cathode 11 is neutralized, so that electrons are sufficiently emitted and accelerated to an energy comparable to the anode voltage. Here, since the anode 12 is an open type anode, most of the electrons penetrate the wide space behind the anode 12. In the back space, electrons collide with the light emitting gas 10 made of mercury to cause excitation and ionization, and light emission occurs. The ultraviolet light generated by this light emission strikes the phosphor 9 and emits visible light to the tube 8.
Discharge to the outside. If the phosphor 9 is not applied, ultraviolet rays will be emitted. By the way, since the dimension of the tube body 8 is about several times to 10 times the mean free path of electrons, electrons can be sufficiently diffused except between the cathode 11 and the anode 12, and light emission can be sufficiently performed in the back space.

By the way, in this embodiment, the emission of electrons from the cathode 11 is made sufficient, and the applied voltage to the anode 12 is set to 1
By setting the voltage to 0 V, the discharge with the anode 12 becomes a negative resistance discharge, the ionization (and thus excitation) multiplication effect is large, the ionization (excitation) efficiency is improved, and as a result, the light emission efficiency is increased. Further, sufficient discharge and ionization are performed, so that ions are sufficiently generated, space charges near the cathode 11 are more effectively neutralized, and an ion sheath is formed in the cathode 11 to efficiently emit electrons. Further, since the ions plunge into the cathode 11, the cathode 11 is effectively heated, and as a result, the function of the cathode 11 works efficiently with less electric power. Further, since a sufficient current can be passed, high-luminance light emission can be obtained, and further, the lamp voltage does not increase even if the input is increased, so that the DC power supply 13 can be a voltage stop power supply.

FIG. 2 shows the current-voltage characteristics of this embodiment, and FIG. 3 shows a comparison between this embodiment (a) and the conventional general fluorescent lamp (b). In this embodiment, the starting voltage a, It can be seen that the required power supply voltage b and the operating voltage c are lower than those a ', b', c'of the conventional example.

Example 2 FIG. 4 shows Example 2 of the present invention, in which the tube 8 of the lamp of this example comprises a cylindrical bulb having a diameter of about 30 mm and a flow rate of about 50 mm, and the anode 12 comprises a ring-shaped nickel electrode. The cathode 11 is an indirectly heated barium-impregnated cathode. A few to several tens of mg of mercury is enclosed as a light emitting gas 10 in the tube 8 so as to be about several mm Torr during operation, and calcium halophosphate is used as the phosphor 9 applied to the inner peripheral surface and the inner ceiling of the tube 8. Alternatively, a white phosphor made of a combination of rare earths is used. Therefore, in the lamp of this example, the lamp voltage was about 20 V, the lamp power was about 5 W, the luminous flux was about 150 m, and the brightness in the space behind the anode 12 was about 10,000 Cd / m ² . A transistor constant current / switching circuit is used as the lighting circuit, and the transistor Tr is controlled so that the current set by the zener diode ZD and the resistor R flows through the lamp. The light intensity can be adjusted by changing the amplitude and the amplitude. Reference numeral 15 in the drawing is a power source for heating the filament 16.

Although the phosphor 9 is coated on the inner ceiling surface and the inner peripheral surface in the above-described embodiment, the light emitting surface as the display may be only the ceiling surface, and thus the coating surface may be only the inner ceiling surface.

Embodiment 3 This embodiment is such an embodiment of the second invention in which the brightness and the luminous efficiency are further improved as compared with the above-mentioned embodiment, and in this embodiment, as shown in FIG. Tube 8
The ring-shaped cathode is used as the anode 12 and is applied only to the inner ceiling surface of the tube. Outside the one end of the tubular body 1 close to the cathode 11, the electric field between the cathode 11 and the anode 12 is substantially parallel. A magnet 17 composed of a permanent magnet or an electromagnet for applying a static magnetic field in the direction is closely arranged.

Then, the electrons that come out of the cathode 11 and penetrate through the anode 12 are subjected to a force by the magnetic field and swirl around the magnetic line of force x shown in FIG. That is, in addition to the original electric force due to the electric field, a force due to the magnetic field is applied, and as a result, a movement in the form of a so-called magnetic force line trap that is wrapped around the magnetic force line x occurs. Therefore, as a result, electrons gather at the strong magnetic field line x, that is, at the center of the tube body 8 shown in FIG.
There is no waste that electrons are diffused into the entire tube body 8 as in the case where there is no magnetic field as shown in FIG. Furthermore, since the motion of the electrons is a small swirling motion around the magnetic field line x as shown in Fig. 8, it shows the property that the mean free path is smaller than that in the case without the magnetic field shown in Fig. 9, The chances of colliding with and excitating the light emitting gas 10 made of mercury increases. That is, the excitation efficiency of electrons per electron is increased, and the overall emission efficiency is improved.

Next, the state of electrons passing through the anode 12 is as follows when compared with the case where there is no magnetic field as in the first embodiment. That is, without a magnetic field, electron energy close to the potential of the anode 12 is obtained on average as shown in FIG. 10 as shown in FIG. 10, but in the presence of a magnetic field as shown in FIG. Since the energy is mainly determined by the spatially distributed potential,
As shown in FIG. 13, the energy is lower than that without a magnetic field, and as a result, the luminous efficiency is approached to 5 to 10 eV, which is desirable for excitation of ultraviolet rays of 254 nm, and the luminous efficiency is improved.

As described above, in the present embodiment, the effect of improving the light emission luminance in the specific direction and the light emission efficiency by the application of the static magnetic field is added to the effect of using the negative characteristics. The strength of the magnetic field generated by the magnet 17 is set so that the Larmor radius of electrons near the anode 12 in the tube 8 is 0. Several to several tens of mm (for example, 0.1 mm to 0.3 m
The magnetic field strength is such that m).

Example 4 Although the tubular body 8 of each of the above-mentioned examples was a short-length cylindrical tubular body,
The present embodiment is an embodiment corresponding to the third aspect of the present invention, which realizes a highly efficient single-base lamp that emits light sufficiently over the whole even with a thin straight tubular body 8.

In this embodiment, as shown in FIG. 14, a thin straight tubular body 8
A cathode 11 and a mesh-shaped or ring-shaped open-type anode 12 are arranged at one end side of the tube body, and magnets 17a and 17b made of permanent magnets or electromagnets are closely arranged outside both ends of the tubular body 8. There is. Then, the phosphor 9 is applied to the inner peripheral surface of the tube body 8 corresponding to the space behind the anode 12,
Further, the light emitting gas 10 made of mercury is enclosed so that the internal pressure of the tube becomes several mm Torr during operation.

The polarities of the opposing magnets 17a and 17b are different.

In this embodiment, however, as shown in FIG. 15 (a), the electrons penetrating the anode 12 due to the magnetic field line x in the tube axis direction swirl around the magnetic field line x as shown in FIG. And move in the space behind the anode 12. As a result, the light emitting gas 10 made of mercury collides with the light emitting gas 10 on the way to move to cause excitation and light emission.
As shown in (b), light is emitted substantially uniformly over the entire space behind the anode 12. The difference from the third embodiment is that in the third embodiment, the magnet 17 is provided on the cathode 11 side, and the magnetic field lines x are distributed in the diffusion direction, so that the light emission slightly spreads out like a fan in the space behind the anode 12. In the example, the line of magnetic force x is narrowed at both ends of the tube body 8, so that electrons are confined in the long back space and uniformly emit light. Note that the strength of the magnetic field generated by the magnets 17a and 17b is set so that the Larmor radius of electrons near the anode in the tube is 0. Several to several tens of mm (for example, 0.1 mm to 0.3 mm)
The magnetic field strength is such that

Fifth Embodiment This embodiment is a modification of the fourth embodiment and includes magnets 17a and 17a.
The magnetic field intensity of b is weakened, the distribution of the magnetic field lines x is widened as shown in FIG. 17, and a tubular body such as a rugby ball can be used as the tubular body 8.

Although the light emitting gas 10 in each of the above embodiments is mercury, it may be a light emitting gas such as sodium or cesium.

[Advantages of the Invention] In the first invention, an electron emission cathode and a mesh-shaped or ring-shaped opening anode are arranged close to each other at one end in the tubular body, and the distance between the anode and the cathode is sufficiently larger than the entire length of the tubular body. It is set small, and the space opposite the cathode side of the anode is made sufficiently wide. A small amount of light emission gas is sealed in the tube so that the pressure is several mm Torr during operation, and voltage is applied between the anode and cathode. Since it is equipped with a discharge power source means for generating a negative resistance discharge, it is possible to emit light in the space behind the anode. Therefore, a single-ended mold lamp in which the anode and the cathode are arranged at one end of the tube is provided. It can be realized, and the anode and cathode can be appropriately shortened, and the pressure inside the tube is a low pressure of only the light emitting gas, so it is possible to start and maintain lighting at a low power supply voltage. Due to the anti-characteristic operation, the efficiency of the function of the cathode is high, high brightness and low lamp voltage can be maintained, and because of the above-mentioned configuration, light emission can be turned on and off easily and at high speed by turning on and off the anode voltage. Therefore, the present invention can be applied to displays and the like, and has the effect of being inexpensive because of its simple structure. Further, in the second invention, a cathode / anode is provided outside one end of the cathode side tube. Since a static magnetic field is applied in a direction substantially parallel to the electric field between the electrons, electrons can be swirled along the lines of magnetic force, and it is possible to improve the emission brightness in a specific direction and the emission efficiency. In addition to the effects of the first aspect of the invention, the third aspect of the invention is that the magnets are arranged outside one end of the tube body on the cathode side and the other end of the tube body on the opposite side so that the polarities are opposite to each other. Long body However, since electrons can be moved between both ends of the tube without being diffused, even if the space behind the anode is long, it can uniformly emit light, and the magnets at both ends generate a magnetic field suitable for the shape of the tube. The effect that the entire tubular body can be made to uniformly emit light by being formed is achieved together with the effect of the first invention.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of Embodiment 1 corresponding to the first invention, FIGS. 2 and 3 are operational characteristic explanatory diagrams of the same, and FIG. 4 is a schematic configuration diagram of Embodiment 2 of the same, and FIG. Is a schematic configuration diagram of a third embodiment corresponding to the second invention, and FIGS. 6 to 13 are the same as the third embodiment.
14 is an operation explanatory diagram of FIG.
15 to 16 are schematic diagrams for explaining the operation of the above-mentioned fourth embodiment, FIG. 17 is a schematic configuration diagram of the above-mentioned fifth embodiment, and FIGS. 18 and 19 are schematic structures of a conventional example, respectively. Figure 8
Is a tube, 10 is a light emitting gas, 11 is a cathode, 12 is an anode, and 17, 17a and 17b are magnets.

Claims (5)

[Claims] 1. An electron emission cathode and a mesh-shaped or ring-shaped opening anode are arranged in close proximity to one end in the tube body, and the distance between the anode and the cathode is set sufficiently smaller than the entire length of the tube body. Moreover, the space on the side opposite to the cathode of the anode is made sufficiently wide, and a small amount of light emission gas is enclosed in the tube so that the pressure becomes several mmTorr during operation, and a voltage is applied between the anode and the cathode to make it negative. A low-pressure discharge lamp comprising a discharge power source means for generating a resistance discharge. 2. The low pressure discharge lamp according to claim 1, wherein the light emitting gas is mercury. 3. An electron emission cathode and a mesh-shaped or ring-shaped opening anode are arranged in close proximity to one end in the tube body, and the distance between the anode and the cathode is set sufficiently smaller than the entire length of the tube body, Moreover, the space opposite to the cathode side of the anode is made sufficiently wide, and a small amount of light emission gas is enclosed in the tube body so that the pressure becomes a few mmTorr during operation, and the cathode and anode are provided outside one end of the cathode side tube body. Between the anode and the cathode, and a discharge power source means for generating a negative resistance discharge by applying a voltage between the anode and the cathode. Low pressure discharge lamp to be. 4. The strength of the static magnetic field is set so that the Larmor radius of electrons near the anode in the tube is 0. The low pressure discharge lamp according to claim 3, characterized in that the magnetic field strength is set to several mm to several tens mm. 5. An electron emission cathode and a mesh-shaped or ring-shaped opening anode are arranged in proximity to one end in the tube body, and the distance between the anode and the cathode is set sufficiently smaller than the entire length of the tube body. In addition, the space opposite the cathode side of the anode is made sufficiently wide, and a small amount of light emission gas is enclosed in the tube body so that the pressure becomes a few mmTorr during operation, and the tube body outside the cathode side and on the opposite side. A magnet is disposed outside the other end of the battery so that the polarities thereof are opposite to each other, and a discharge power supply means for applying a voltage between the anode and the cathode to generate a negative resistance discharge is provided. Low pressure discharge lamp.