JPH0531266B2 - - 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 it accelerates the thermoelectrons emitted by one cathode 2a, forms them into a beam and makes them reach the anode 3, decelerates them after passing through the anode 3, and transfers them to the other cathode 2b. The speed is set so that it reaches 0 just before reaching the target.

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 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. .

FIG. 2 shows a principle diagram of the present invention, and shows a material that is transparent to desired light radiation (here, light radiation includes ultraviolet radiation and infrared radiation), such as transparent glass. A first cathode 2a of the thermoelectron emission type is disposed inside the tube body 1 which is airtightly formed, and is located at a distance from the cathode 2a.
An electron-transmissive anode 3 is disposed at a position _L1 , and a thermionic-emitting second cathode 2b is disposed at a distance _L2 from the cathode 2a. Here, if the mean free path of the 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 collision with electrons and emit light is sealed inside the tube 1, and the inner surface of the tube 1 is filled with a fluorescent gas as needed. A light body is deposited.

The first and second cathodes 2a, 2b
A heating power source 6 is connected to each end of the
A DC power supply 5 is connected between the first cathode 2a and the anode 3, and applies a voltage such that the electrons have enough energy to sufficiently ionize the enclosed atoms. Further, a DC power supply 7 is connected between the first cathode 2a and the second cathode 2b, and applies a voltage (lower than the ionization voltage) having the optimum energy to excite the enclosed atoms.

Next, the operation will be explained with reference to FIG.

Electrons drawn from the first cathode 2a toward the anode 3 by the DC power supply 5 collide with the enclosed atoms after passing through the anode 3, and ionize the enclosed atoms. In this case, since there is no accelerating electric field for both electrons and ions after ionization, subsequent ionization does not occur. In other words, the current-voltage characteristics are positive. Then, when the space is neutralized by ionization, electrons are accelerated from the second cathode 2a toward the first cathode 2a by the power source 7. This voltage is only sufficient to excite the enclosed gas and is not high enough to cause ionization. Therefore, the electrons emitted from the second cathode 2b collide with the encapsulated material on the way, and drift toward the first cathode 2a while exciting the encapsulated material. Since these electrons do not cause ionization, the current-voltage characteristic becomes positive and no current limiting element is required.

Note that the voltage for causing excitation may be obtained from the AC power supply 9 as shown in Figure 4. With this configuration, the cathode and anode change every half cycle, so that the voltage generated during DC lighting It also has the additional effect of preventing cataforesis, which tends to occur.

(Effects of the Invention) As described above, the present invention comprises 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 cathode 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, and the first cathode and Applying an optimal voltage between the second cathode to excite the light emitting gas,
By separating the electrons that cause ionization and the electrons that cause light emission, there is no need for a current limiting element.
Moreover, it was possible to provide a light-emitting electron tube with high luminous efficiency.

[Brief explanation of the drawing]

FIG. 1 is a principle diagram of a conventional example, FIG. 2 is a principle diagram 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. 1... tube body, 2a, 2b... cathode, 3...
Anode, 5, 6, 7, 9... power supply.

Claims (1)

[Claims] 1. A tube in which a low-pressure light emitting gas is sealed and is transparent to light radiation, a thermionic emission type first cathode disposed within the tube, and a distance from the cathode. an electron-transmissive anode disposed at a position where is shorter than the mean free path of electrons; and a thermionic-emitting second cathode disposed at a position where the distance from the cathode is longer than the mean free path of electrons. A light-emitting electron tube comprising: applying a voltage sufficient to ionize the light-emitting gas between the first cathode and the anode; and applying a voltage sufficient to ionize the light-emitting gas between the first cathode and the second cathode. A light-emitting electron tube characterized by applying the optimum voltage to excite.