JPS61190851A - Light-emission electron tube - Google Patents

Abstract

PURPOSE:To enhance the light emission efficiency of a light-emission electron tube, in the light-permeable body of which a low-pressure light emission gas, a cathode and an anode are sealed, by providing an electroconductive substance located in all the space behind the anode and having almost the same potential as the anode. CONSTITUTION:A low-pressure light emission gas, which emits light due to the collision of electrons of evaporated mercury or the like with the gas, a cathode and a reticulate anode 3 are sealed in the light-permeable body 1 of a light-emission electron tube. The electrons having passed through the anode 3 are caused to collide with the gas is a back space 4 to generate ultraviolet rays which are changed into visible light through a fluorescent substance on the inside surface of the tube body 1. An electroconductive substance 7 having voids such as those of wool is provided in the whole back space 4. The potential on the substance 7 is kept nearly equal to that on the anode 3 so that the electrons having entered into the back space 4 are not pulled back to the anode 3 but cause the stimulated emission of light. The light emission efficiency of tube is thus enhanced.

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 bombardment with electrons and emits light outside the tube.

(Background Art) As a prior art, for example, there is a lamp as disclosed in Japanese Patent Application Laid-Open No. 57-130364 (Japanese Patent Application No. 56-2.06266).

In such a lamp, as shown in FIG. 1, the inside of the tube 1 is not completely vacuumed, but the mercury vapor is heated to several mTorr, for example.
A low vacuum of about r is used, and a thermionic emission type cathode 2 is used.
The emitted electrons are accelerated by applying an electric field, and by forming the anode 3 into a mesh-like or lattice-like structure, most of the electrons pass through, and the back space 4 emits ultraviolet radiation like mercury vapor and air. The mercury is collided with a gas to excite the mercury to generate ultraviolet radiation, and this ultraviolet radiation is applied to a phosphor (ultraviolet-excited type) coated on the inner surface of the tube body 1 to perform the desired visible light conversion.

In addition, in the figure, 5 is a DC power supply, and 6 is a resistor.

By the way, in the conventional technology, the electrons after causing excited light emission are collected at the anode 3. This means that the electrons that have entered the back space 4 are always pulled toward the anode 3 by an electric force (that is, are subjected to negative acceleration).

As a result, as shown in FIG. 2, electrons no longer reach the part of the back space 4 close to the inner wall surface of the tube body 1 (the shaded part 4'' in the figure), making it impossible to make the entire back space 4 emit light. could not.

(Object of the Invention) The present invention has been made to improve the above-mentioned drawbacks, and its purpose is to provide a light-emitting electron tube in which electrons incident on the back space cause excited light emission throughout the space. It is in.

(Disclosure of the Invention) The present invention comprises: a tube body in which a low-pressure light emitting gas is sealed and is transparent to light radiation; a thermionic emission type cathode disposed inside the cough tube body; In a light-emitting electron tube comprising an electron-transmissive anode disposed at a distance from the cathode that is shorter than the mean free path of electrons, the anode is It is characterized by disposing a conductive material having approximately the same potential as the electric potential.

FIG. 3 shows a principle diagram according to the present invention, and is made of a material that is transparent to the desired light radiation (herein, light radiation includes ultraviolet radiation and infrared radiation), such as transparent glass, to ensure an airtight seal. A thermionic emission type cathode 2 is disposed inside a substantially spherical tube body 1 formed in the tube body 1. Inside the tube body 1, a cathode 2 is excited by the collision of electrons such as a rare gas or vaporized mercury. A low-pressure light-emitting gas capable of emitting light is enclosed,
A fluorescent substance is coated on the inner surface of the tube body 1 as required.

In front of the cathode 2, an electron-transmissive anode 3 having a mesh or lattice shape is disposed, and a conductive material 7 having a certain amount of gap is disposed throughout the space 4 in front of the anode 3 (back space). It is arranged. Here, the distance between the cathode 2 and the anode 3 is shorter than the mean free path of electrons, and the space possessed by the conductive material 7 is also approximately close to the mean free path of electrons. In the figure, 5.8 is a DC power supply, and 6 is a resistor. With this configuration, the potential of the conductive material 7 is set to be the same as or close to the potential of the anode 3.

Next, the operation will be explained. Electrons emitted from the cathode 2 are accelerated by the anode 3. The electrons that have passed through the anode 3 then proceed through a space 4 behind the potential distribution as shown in FIG. 4(b). In conventional light-emitting electron tubes, when electrons pass through the anode 3, a force acts to pull them back to the anode 3. However, in the present invention, the potential distribution is approximately uniform.
Therefore, the electrons proceed at the same speed as when they passed through the anode 3, and the atoms sealed in the tube body 1 (for example, vaporized mercury H
g) collides with and emits excited light. After that, it is absorbed by the nearest conductive material 7.

As the conductive material 7 disposed inside the tubular body 1, it is preferable to use a wool-like material made of a metal that does not form amalgam, such as tungsten wool.
It may also be a series of needle-shaped (non-amalgam-forming) metals. Moreover, FIG. 4 is a characteristic diagram showing the potential distribution inside the tube, (a) is a characteristic diagram according to the conventional example, and (b) is a characteristic diagram according to the present invention. K on the horizontal axis of each figure is the cathode position. of,
A indicates the anode position, and H indicates the inner wall surface position of the tube body 1, respectively.

(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. In a light-emitting electron tube consisting of a cathode of By disposing a conductive material having approximately the same potential as the electric potential, electrons incident on the back space cause excited light emission in approximately the entire area of the space. Therefore, it is possible to provide a light-emitting electron tube with extremely high luminous efficiency.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a conventional light emitting electron tube, Fig. 2 is a schematic diagram explaining the operation of the same as above, Fig. 3 is a schematic diagram of a light emitting electron tube according to the present invention, and Fig. 4 is a potential distribution inside the tube. , +8) is a characteristic diagram according to the conventional example, and (b) is a characteristic diagram according to the present invention. 1... tube body, 2... cathode, 3... anode,
4... Back space, 7... Conductive material.

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 cathode disposed inside the tube, and a distance from the cathode. In a light-emitting electron tube consisting of an electron-transmissive anode disposed at a position shorter than the mean free path of electrons, a conductive material having approximately the same potential as that of the anode is provided over substantially the entire space in front of the anode. A light-emitting electron tube characterized in that: