JPS61190852A - Light-emission electron tube - Google Patents

Abstract

PURPOSE:To enhance the light emission efficiency of a light-emission electron tube, in the light-permeable tube body of which a low-pressure light emission gas, a cathode and an anode are sealed, by providing a plurality of electroconductive members of the same form as the anode behind it. 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 2 and a reticulate anode 3 are sealed in the light-permeable tube body 1 of a light-emission electron tube. The electrons having passed through the anode 3 are caused to collide with the gas in 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. A plurality of electron-permeable electroconductive members 7 having the form as the anode 3 are provided in the back space 4 and disposed at intervals each nearly equal to the mean free path of the electrons, so that the electrons having entered into the back space are repeatedly accelerated and spread in the whole space. Space charge is thus removed to enhance the light emission efficiency of the tube.

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. 56-206266).

As shown in FIG. 1, in such a lamp, the inside of the tube 1 is not completely vacuumed, but the inside of the tube 1 is kept under a vacuum of 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 mehshe-like or lattice-like structure, most of the electrons pass through, and are converted into ultraviolet emitting gas such as mercury vapor in the back space 4. The collision excites mercury and causes ultraviolet radiation, and this ultraviolet radiation is transmitted to tube body 1.
It is applied to a phosphor (ultraviolet-excited type) coated on the inner surface of the lamp to perform the desired visible light conversion.

Note that in the figure, 5 is a DC power supply, and 6 is a resistor.

By the way, in the prior art, as shown in FIG. 2, the electrons emitted from the cathode 2 are accelerated by the anode 3, and after passing through the anode 3, they collide with the enclosed substance (e.g., vaporized mercury Hg), and the electrons are change. the result,
A space charge is generated near the front surface of the anode 3. This space charge is caused by electrons newly emitted from the cathode 2
This has the disadvantage that the light is prevented from entering the space 4, resulting in a significant drop in luminous efficiency.

(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 with high luminous efficiency by removing the space charge generated in the back space. There is something to do.

(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; a thermionic-emitting cathode disposed within the tube; In a light-emitting electron tube consisting of an electron-transmissive anode disposed at a distance from the cathode that is less than the mean free path of electrons, a space in front of the anode (back space) has a shape similar to that of the anode. It is characterized in that a plurality of electron-transmissive conductors (for example, metal meshes) are arranged at intervals approximately equal to the mean free path of electrons.

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-emitting cathode 2 is disposed inside a substantially spherical tube 1 formed in the tube 1. Inside the tube 1, a cathode 2 is excited by the collision of electrons such as a rare gas and vaporized mercury. A low-pressure light emitting gas capable of emitting light is sealed, and a fluorescent material 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 the anode 3
In the front space (back space) 4, a plurality of conductors 7 having the same shape as the anode 3 and allowing electrons to pass therethrough, such as a metal mesh, are arranged. Here, the distance between the cathode 2 and the anode 3 is shorter than the mean free path of electrons, and the distance between the anode 3 and the conductor 7 and the distance between adjacent conductors 7 are each approximately equal to the mean free path of the electrons. are set equal. Note that in the figure, 5 is a DC power supply, and 6 is a resistor.

Next, the operation will be explained. Electrons emitted from the cathode 2 are accelerated by the anode 3. After passing through the anode 3, it collides with the enclosed substance (e.g., vaporized water tlHg), changes its direction of travel, and loses energy.
The electrons are accelerated again by the anode 3, or by the conductor 7, which is the same type and position as the anode 3, or has a high potential, depending on the position where the electrons exist. The electrons accelerated by the anode 3 repeat the same movement and are finally absorbed by the anode 3. Further, electrons accelerated by the conductor 7 pass through the conductor 7. After passing through the conductor 7, the electrons collide with the encapsulating material and are accelerated again by the next conductor 7 or the conductor 7 that has passed. Electrons repeatedly perform such movements, therefore, by accelerating the electrons many times in this manner and spreading the distribution over the entire tube body 1, the influence of space charges can be reduced.

(Effects of the Invention) As described above, the present invention includes a tube in which a low-pressure light emitting gas is sealed 5 and is transparent to light radiation, and a thermionic radiation disposed inside the tube. In a light-emitting electron tube consisting of a shaped cathode and an electron-transmissive anode disposed at a distance from the cathode that is shorter than the mean free path of the electrons, electrons are placed in a space in front of the anode in the same shape as the anode. By arranging multiple conductive conductors at intervals approximately equal to the mean free path of electrons, we were able to reduce the influence of space charge and provide a more efficient light-emitting electron tube. .

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a conventional light-emitting electron tube, FIG. 2 is a schematic diagram illustrating the operation of the same, and FIG. 3 is a schematic diagram of a light-emitting electron tube according to the present invention. 1... tube body, 2... cathode, 3... anode,
4... Back space, 7... Electric conductor.

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 anode that allows electrons to pass and is placed at a position shorter than the mean free path of electrons, a conductor that has the same shape as the anode and that allows electrons to pass is placed in the space in front of the anode to reduce the mean free path of electrons. A light-emitting electron tube characterized in that a plurality of light-emitting electron tubes are arranged at intervals substantially equal to the stroke.