JPH0564416B2 - - 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 tubular body in which a low-pressure light emitting gas is sealed and is transparent to light radiation, and two thermionic-emitting cathodes disposed within the tubular body. and an electron-transmissive anode, in which a current-voltage characteristic is made positive, thereby eliminating the need for a current-limiting element and achieving higher luminous efficiency. .

Hereinafter, the present invention will be explained in detail based on Examples.

Embodiment 1 FIG. 2 shows a principle diagram according to the first embodiment of the present invention. A first cathode 2a of the thermionic emission type is disposed inside the tube body 1, which is airtightly formed of a material having a material such as _transparent glass. An anode 3 is arranged, and further a distance L ₂ from the anode 3
A thermionic emission type second cathode 2b is disposed at the position. Here, the mean free path of the electron is λ
Then, there is a relationship L ₁ <λ<L ₂ . In addition,
A low-pressure light-emitting gas such as a rare gas or vaporized mercury that can be excited by the collision of electrons and emit light is sealed inside the tube 1, and a phosphor is provided on the inner surface of the tube 1 as necessary. is deposited. A heating power source 6 is provided at both ends of each of the cathodes 2a and 2b.
is connected, and a DC power supply 5 is connected between the anode 3 and the first cathode 2a.

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 mercury.

Electrons drawn from the first cathode 2a toward the anode 3 by the DC power supply 5 collide with mercury atoms after passing through the anode 3, and ionize the mercury atoms. As a result, the space is electrically neutralized, electrons emitted from the cathode 2a are allowed to enter the entire interior of the tube 1 (without being affected by space charges), and the neutralization of the entire interior of the tube 1 is maintained. Therefore, the energy of the incident electron is quite high (+ several eV) to cause the excited emission of mercury atoms. This high energy electron (high energy electron)
is a low-energy thermal electron (low-energy electron) of several eV or less emitted from the second cathode 2b.
By colliding with the electrons, the energy of each electron is averaged. The averaged energy (5 to 10 eV) is optimal for excitation and emission of mercury atoms.

Incidentally, although the emitted electrons from the first cathode 2a ionize mercury atoms, this hardly occurs between the first cathode 2a and the anode 3.
Therefore, the current-voltage characteristic becomes positive and no current limiting element is required.

Embodiment 2 FIG. 4 shows a principle diagram according to a second embodiment of the present invention, which includes a first cathode 2a and an electron-transmissive structure disposed at a position shorter than the mean free path of electrons from the cathode 2a. A voltage is applied between the anode 3 and the anode 3 so that the electrons have enough energy to sufficiently ionize the enclosed atoms, emitting high-energy electrons, and the electron has a mean free path longer than the mean free path of the electron from the anode 3. A voltage (lower than the ionization voltage) that has the optimum energy to excite the enclosed atoms is applied between the second cathode 2b and the second cathode 2b disposed at the same position, thereby emitting low-energy electrons. It is. Note that the first
Components that are equivalent to those in the embodiment are given the same reference numerals.

Next, the operation of the above embodiment will be explained with reference to FIG. The first cathode 2a is connected by the DC power supply 5.
After passing through the anode 3, the electrons (high-energy electrons) extracted from the source toward the anode 3,
It collides with the enclosed atoms and ionizes them. In that case, since there is no accelerating electric field after ionization, no electron avalanche is caused. Then, when the space is neutralized by ionization, the second cursode 2
Electrons are accelerated by the DC power source 7 from b toward the anode 3. This voltage is only sufficient to excite the enclosed gas and is not high enough to cause ionization. Therefore, the electrons (low-energy electrons) emitted from the second cathode 2b collide with the encapsulated material on the way and drift toward the anode 3 while exciting the encapsulated material. Since these low-energy electrons do not cause ionization, the current-voltage characteristic becomes positive and no current limiting element is required.

(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 a thermionic emission type disposed inside the tube. 1st of
a cathode, an electron-transmissive anode disposed at a position where the distance from the cathode is shorter than the mean free path of electrons, and a thermal anode disposed at a position where the distance from the anode is longer than the mean free path of electrons. A light-emitting electron tube comprising an electron-emitting second cathode, wherein a voltage sufficient to ionize the light-emitting gas is applied between the first cathode and the anode to emit high-energy electrons. By emitting low-energy electrons from the second cathode to separate electrons that cause ionization and electrons that cause light emission, it is possible to provide a light-emitting electron tube with positive current-voltage characteristics and high luminous efficiency. Ta.

[Brief explanation of drawings]

Fig. 1 is a principle diagram of a conventional example, Fig. 2 is a principle diagram showing a first embodiment of the present invention, Fig. 3 is an explanatory diagram of the same operation, and Fig. 4 is a principle diagram showing a second embodiment of the present invention. figure,
FIG. 5 is an explanatory diagram of the same operation as above. 1... tube body, 2a, 2b... cathode, 3...
Anode, 5, 6, 7...DC power supply.

Claims (1)

[Scope of Claims] 1. A tube in which a low-pressure light emitting gas is sealed and is transparent to light radiation, and a thermionic-emitting first cathode disposed within the tube. , an electron-transmissive anode disposed at a position where the distance from the cathode is shorter than the mean free path of electrons, and a thermionic emission type disposed at a position where the distance from the anode is longer than the mean free path of electrons. A light-emitting electron tube comprising: a second cathode;
A light-emitting electron tube characterized in that a voltage sufficient to ionize a light-emitting gas is applied between the cathode and anode of the light-emitting gas, and high-energy electrons are emitted therefrom, and low-energy electrons are emitted from the second cathode. . 2. The low-energy electrons collide with the high-energy electrons to average their energy, and have an energy value such that the averaged energy value is an optimal value for exciting the light-emitting gas. The light-emitting electron tube according to claim 1, which is an electron. 3. The light-emitting electron tube according to claim 1, wherein the low-energy electrons are electrons having an energy value optimal for exciting the light-emitting gas.