JPH0564417B2 - - Google Patents

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a light-emitting electron tube that excites a light-emitting gas sealed inside the tube by collision with electrons and emits light outside the tube.

(Background Art) As a prior art, for example, there is a lamp as shown in Japanese Patent Application No. 106230/1982.

Such a lamp, as shown in FIG. A pair of cathodes 2a, 2b is disposed inside the tubular body 1, and at least one of the cathodes 2a, 2b is of the thermionic emission type (for convenience of explanation,
In the figure, the cathode 2a on the left side is a thermionic emission type cathode). Both cathodes 2a, 2b mentioned above
An electron-permeable anode 3 having a mesh or lattice shape is disposed approximately in the middle of the electrode. Also,
A low-pressure light-emitting gas such as a rare gas or vaporized mercury that can be excited by collision with electrons and emit light is sealed inside the tube 1 . A DC voltage is applied between the anode 3 and the cathodes 2a, 2b by a DC power source 5 via a resistor 4, respectively. The magnitude of the DC voltage is such that the thermoelectrons emitted from one cathode 2a are accelerated, formed into a beam shape, and reach the anode 3;
After passing through the anode 3, the speed is decelerated, and the speed is set to zero just before reaching the other cathode 2b.

Next, to briefly explain the operation of the lamp configured as described above, electrons emitted from the thermionic emission type cathode 2a are accelerated by the electric field, and most of them pass through the anode 3 as they are and enter the deceleration electric field region. The electrons enter the cathode 2b, stall just before the cathode 2b, and have a velocity of 0, which accelerates them in the opposite direction. in this way,
The electrons reciprocate around the anode 3 and collide with the enclosed substance (e.g., vaporized mercury) many times to cause excited light emission, which results in more efficient ultraviolet radiation and a lamp with high luminous efficiency. It is said that it will be done.

However, the anode 3 and cathode 2a, 2
If the distance b is long, the electrons will collide with mercury atoms between them, and will not pass through the anode 3 unless a fairly high voltage is applied. Moreover, in that case,
The current-voltage characteristic is negative, and a current limiting element is required like a general discharge lamp, so there is no difference from a general discharge lamp. Furthermore, when the voltage is low, space charges are generated due to non-ionizing collisions between electrons and mercury atoms, and the electrons do not pass through the anode 3.

On the other hand, if the distance between the anode 3 and cathodes 2a, 2b is short, the phenomenon according to the above theory may occur;
It was found that because the light emitting area itself was small, the overall luminous flux was low.

(Object of the Invention) The present invention has been made to improve the above-mentioned problems, and its purpose is to take advantage of the characteristics of a light-emitting electron tube, that is, its positive current-voltage characteristics. Another object of the present invention is to provide a lamp with higher luminous efficiency.

(Disclosure of the Invention) The present invention comprises a tube in which a low-pressure light emitting gas is sealed and is transparent to light radiation, and two thermionic-emitting cathodes disposed within the tube. and two anodes (at least one of which is electron-transmissive), the distance between one cathode and the anode (which is electron-transmissive) is shorter than the mean free path of electrons, and By making the distance between the other cathode and the anode sufficiently longer than the mean free path of electrons, the light emitting region is expanded and the light emitting efficiency is increased.

FIG. 2 shows a diagram of the principle of the present invention, and is made of a material that is transparent to desired light radiation (here, light radiation includes ultraviolet radiation and infrared radiation), such as transparent glass. Inside the airtight tubular body 1, first and second cathodes 2a and 2b of thermionic emission type are disposed, and an electron-permeable electrode is placed at a distance L ₁ from the first cathode 2a. a first anode 3a, and a second cathode 2b
Second anodes 3b are disposed at distances L ₂ from each other. Here, if the mean free path of an electron is λ, then there is a relationship L ₁ <λ<L ₂ .
Note that a low-pressure light-emitting gas such as a rare gas or vaporized mercury that can be excited by electron collision and emit light is sealed inside the tube 1, and the inner surface of the tube 1 is filled with fluorescent gas as needed. The body is covered. and,
A heating power source 6 is connected to both ends of each of the cathodes 2a and 2b, and there is a gap between the first anode 3 and the first cathode 2a such that electrons have enough energy to ionize the enclosed substance. A DC power supply 7 for applying voltage is connected, and a voltage (lower than the ionization voltage) having the optimum energy to excite the enclosed substance is applied between the second anode 3b and the second cathode 2b. A DC power supply 8 for supplying the power is connected.

Next, the operation of the above embodiment will be explained with reference to FIG. 3, taking as an example the case where the light emitting gas is vaporized mercury.

Electrons extracted from the first cathode 2a toward the first anode 3a by the DC power source 7 collide with mercury atoms after passing through the anode 3a, thereby ionizing the mercury atoms. In that case, there is no accelerating electric field after ionization, so no electron avalanche occurs. Therefore, the first cathode 2a
The current-voltage characteristic between the first anode 3a and the first anode 3a is positive. Then, when the space is neutralized by ionization, the transition from the second cathode 2b to the second anode 3b
The electrons are accelerated by the DC power supply 8.
This voltage only excites the mercury atoms,
Not high enough to cause ionization (e.g. 5eV ~
9eV). Therefore, the electrons emitted from the second cathode 2b collide with mercury atoms on the way and drift toward the second anode 3b while exciting them. Since these electrons do not cause ionization, the current-voltage characteristics are still positive. Therefore, no current limiting element is required to operate the lamp according to the invention.

The arrangement of both cathodes 2a and 2b is shown in FIG.
It may be configured as shown in .

(Effects of the Invention) As described above, the present invention includes a tube in which a low-pressure light emitting gas is sealed and is transparent to light radiation, and two thermoelectrons disposed inside the tube. a radiation-type cathode and a cathode, at least one of which is electron-transmissive;
In a light-emitting electron tube comprising two anodes, the distance between one cathode and an electron-transmissive anode is made shorter than the mean free path of electrons, and a voltage sufficient to ionize the light-emitting gas is applied therebetween. , by making the distance between the other cathode and the other anode sufficiently longer than the mean free path of electrons, and applying an optimal voltage to excite the light-emitting gas between them, causing electrons that cause ionization and light emission. The electrons can be separated and the area for causing light emission can be extended throughout the tube. Therefore, according to the present invention, a light-emitting electron tube with positive current-voltage characteristics, no need for a current limiting element, and a wider light-emitting area, that is, with high light-emitting efficiency, can be provided.

[Brief explanation of the drawing]

Fig. 1 is a principle diagram of a conventional example, Fig. 2 is a principle diagram showing an embodiment of the present invention, Fig. 3 is an explanatory diagram of the same operation, and Fig. 4 is a principle diagram showing a different embodiment of the present invention. be. 1... tube body, 2a, 2b... cathode, 3a,
3b...anode, 6,7,8...power supply.

Claims (1)

[Claims] 1 A tube in which a low-pressure light emitting gas is sealed and is transparent to light radiation, two thermionic emission type cathodes disposed within the tube, and at least one of which is electron-transmissive. In a light-emitting electron tube comprising two anodes, the distance between one of the cathodes and the electron-transmissive anode is made shorter than the mean free path of electrons, and a voltage sufficient to ionize the light-emitting gas is applied between the two anodes. A light-emitting electron tube characterized in that the distance between the other cathode and the other anode is sufficiently longer than the mean free path of electrons, and an optimum voltage for exciting a light-emitting gas is applied therebetween.