JPH04286855A - Electroluminescent device - Google Patents

Abstract

PURPOSE:To prevent an electron beam source from deteriorating due to the collision of positive ions of a gas remaining in a glass container. CONSTITUTION:A transparent electrode 2 is formed at a site of the inner circumference of a glass container 1 whose inside is made vacuum. A phosphor layer is formed on the surface of the transparent electrode 2 and an electric field radiating-type electron beam source 4 is set on the opposite to the phosphor layer 3 in the glass container 1. An anode of an electric power source 6 is connected with the transparent electrode 2 and at the same time a cathode of the electric power source 6 is connected with the electron beam source 4 and then electron beam radiated from the electron beam source 4 is radiated to the phosphor layer 3 to emit luminescence. A grid 9 is so set near the electron beam source 4 as to make the electron beam be transmitted. The generation of an electric field toward the electron beam source 4 from the transparent electrode 2 is suppressed by connecting the transparent electrode 2 and the grid 9 with the same voltage.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device which emits light by irradiating a phosphor layer with an electron beam from a field emission type electron beam source.

0002

2. Description of the Related Art Conventionally, as shown in FIG. 5, this type of light emitting device has a phosphor layer 3 disposed opposite to an electron beam source 4, and the electron beam from the electron beam source 4 is emitted from the phosphor layer. It is provided that the layer 3 emits light by irradiating it. The electron beam source 4 is a glass container 1 as a vacuum container whose inside is evacuated.
A transparent electrode 2 is formed on the inner peripheral surface of the glass container 1 at a portion facing the electron beam source 4 . Further, the phosphor layer 3 is deposited on the surface of the transparent electrode 2. Electron beam source 4
An acceleration DC power source 6 is connected between the transparent electrode 2 and the transparent electrode 2 in order to accelerate the electrons 7 emitted from the electron beam source 4.
is connected as the positive terminal.

The electron beam source 4 includes a field emission type gate 4b having a plate-shaped gate 4b formed with a large number of through holes 4a, and a conical emitter 4c disposed corresponding to each through hole 4a. using things. In this electron beam source 4, a gate 4b and an emitter 4c are connected to a cathode DC power source 5 such that the gate 4b becomes a positive electrode, and a strong electric field (for example, 108 V/m or more) is applied between the gate 4b and the emitter 4c. ) to emit electrons from the surface of the emitter 4c. Electrons 7 emitted from emitter 4c
is emitted through the through hole 4a of the gate 4b.

0004

[Problems to be Solved by the Invention] In the above configuration, when the electrons 7 collide with the molecules of the residual gas in the glass container 1 and the molecules of the residual gas are positively ionized, the positive ions 8 are transferred to the electron beam source 4. Since the positive ions 8 are accelerated toward the electron beam source 4 by the electric field generated between the electron beam source 4 and the transparent electrode 2, the positive ions 8 collide with the electron beam source 4 and cause damage, causing deterioration of the electron beam source 4. There was a problem that it could cause

The present invention aims to solve the above-mentioned problems and provides a light-emitting element in which deterioration of an electron beam source due to ionized residual gas is prevented.

[0006]

[Means for Solving the Problems] In claim 1, in order to achieve the above object, there is provided a field emission type electron beam source, which is arranged opposite to the electron beam source and set at a positive potential with respect to the electron beam source. In a light-emitting element, a transparent electrode is placed in a vacuum container with a phosphor layer that emits light when irradiated with electrons emitted from an electron beam source interposed therebetween. A grid connected to the same potential as the transparent electrode is placed nearby.

In claim 2, a field emission type electron beam source;
A transparent electrode placed facing the electron beam source and set at a positive potential with respect to the electron beam source was placed in a vacuum container with a phosphor layer that emits light when irradiated with electrons emitted from the electron beam source sandwiched therebetween. In the light emitting element, a grid set at a positive potential with respect to the electron beam source and the transparent electrode is disposed near the electron beam source between the electron beam source and the phosphor layer.

In claim 3, a field emission type electron beam source;
A transparent electrode placed facing the electron beam source and set at a positive potential with respect to the electron beam source was placed in a vacuum container with a phosphor layer that emits light when irradiated with electrons emitted from the electron beam source sandwiched therebetween. In a light emitting element, a grid set at a positive potential with respect to the electron beam source is placed near the electron beam source between the electron beam source and the phosphor layer, and the electron beam is transferred between the grid and the phosphor layer. An ion collector plate set at a negative potential with respect to the transparent electrode is provided at a position that does not interfere with irradiation to the phosphor layer.

[0009]

[Operation] According to the structure of claim 1, since the grid connected to the same potential as the transparent electrode is disposed near the electron beam source between the electron beam source and the phosphor layer, the phosphor layer Since no electric field is formed between the electron beam and the grid, less of the ionized residual gas generated inside the vacuum vessel is accelerated toward the electron beam source. As a result, damage to the electron beam source due to collision of positive ions in the residual gas with the electron beam source can be suppressed.

According to the structure of claim 2, a grid set at a positive potential with respect to the electron beam source and the transparent electrode is disposed near the electron beam source between the electron beam source and the phosphor layer. Therefore, positive ions generated between the phosphor layer and the grid can be prevented from diffusing into the electric field formed between the transparent electrode and the grid, compared to the structure of claim 1. As a result, the effect of suppressing damage to the electron beam source becomes even higher.

According to the structure of claim 3, a grid set to a positive potential with respect to the electron beam source is arranged near the electron beam source between the electron beam source and the phosphor layer, and the grid and the phosphor layer are arranged at a positive potential with respect to the electron beam source. An ion collector plate set at a negative potential with respect to the transparent electrode is installed at a position that does not impede the irradiation of the electron beam to the phosphor layer. The recombination of positive ions can be promoted, and the effect of suppressing damage to the electron beam source is even higher than that of the structures of claims 1 and 2.

0012

[Example] (Example 1) As shown in FIG.
The basic configuration other than the provision of is the same as the conventional configuration shown in FIG. 5, so the different parts will be mainly explained. As the vacuum container, a glass container 1 which is sealed with a vacuum inside is used. A field emission type electron beam source 4 (described in the prior art) is disposed inside the glass container 1, and a transparent electrode 2 is provided on one surface of the glass container 1 facing the electron beam source 4. It is formed. The transparent electrode 2 is made of ITO (
This is a well-known transparent conductive film formed using indium tin oxide or the like. A phosphor layer 3 is formed on the surface of the transparent electrode 2, and when the phosphor layer 3 is irradiated with electrons 7 emitted from an electron beam source 4, light is emitted. A cathode DC power source 5 is connected to the electron beam source 4, and an accelerating DC power source 6 is connected between the electron beam source 4 and the transparent electrode 2 so that the transparent electrode 2 is the positive electrode. Therefore, the transparent electrode 2 has a positive potential with respect to the electron beam source 4,
Electrons 7 emitted from the electron beam source 4 are accelerated toward the transparent electrode 2.

By the way, there is a phosphor layer 3 inside the glass container 1.
and the electron beam source 4, a grid 9 is placed near the electron beam source 4.
is installed. The grid 9 is formed of metal so that the electrons 7 emitted from the electron beam source 4 can pass therethrough. Further, the grid 9 is connected to the transparent electrode 2 so as to have the same potential. According to the above configuration, since no electric field is formed in the space between the grid 9 and the transparent electrode 2, residual gas ionized into positive ions 8 in this space is not attracted to the electron beam source 4. There isn't. That is, of the positive ions 8 in the residual gas, only the positive ions 8 generated between the electron beam source 4 and the grid 9 have a possibility of colliding with the electron beam source 4. The number of positive ions 8 colliding with 4 is significantly reduced compared to the conventional case. Here, it is considered that the positive ions 8 generated in the above space disappear by recombining with electrons on the peripheral wall of the glass container 1, the phosphor layer 3, etc.

On the other hand, since no electric field is formed between the transparent electrode 2 and the grid 9, the electrons 7 emitted from the electron beam source 4 are accelerated until they reach the grid 9, and then move toward the transparent electrode at approximately the same speed. It will move towards 2. Therefore, if the voltage applied to the transparent electrode 2 is kept the same as in the conventional structure shown in FIG. 5, the energy obtained by the electrons 7 will be the same as in the conventional structure, and the intensity of light emission will not change.

(Embodiment 2) In this embodiment, as shown in FIG. 2, a direct current for preventing diffusion is applied between the transparent electrode 2 and the grid 9 so that the grid 9 has a positive potential with respect to the transparent electrode 2. The power supply 10 is connected. The voltage of the DC power source 10 for preventing diffusion is set to about several volts to about ten-odd volts so that the phosphor layer 3 is not damaged by the ionized residual gas. Furthermore, by providing the diffusion prevention DC power supply 10, the acceleration voltage of the electrons 7 emitted from the electron beam source 4 to the transparent electrode 2 is lowered by the voltage of the diffusion prevention DC power supply 10. It is necessary to set the voltage of 6 to be higher by the voltage of the diffusion prevention DC power supply 10.

According to the above configuration, an electric field directed from the grid 9 toward the transparent electrode 2 is formed in the space between the transparent electrode 2 and the grid 9, and the positive ions 8 generated in the space become electrons. Any attempt to diffuse between the source 4 and the grid 9 will be blocked by the grid 9. Moreover, since the electric field formed in the space by the diffusion prevention DC power source 10 accelerates the positive ions 8 toward the transparent electrode 2, the number of positive ions 8 colliding with the electron beam source 4 is further reduced. Therefore, damage caused by positive ions 8 to the electron beam source 4 can be reliably prevented.

(Embodiment 3) In this embodiment, as shown in FIG. 3, in addition to the structure of Embodiment 1, an ion collector plate 12 is disposed between the grid 9 and the transparent electrode 2. The ion collector plate 12 is disposed at a position where it does not hinder the progress of the electrons 7 emitted from the electron beam source 4. Here, the ion collector plate 12 is assumed to have a cylindrical shape, but it goes without saying that it may have another shape. The transparent electrode 2 and the grid 9 are connected to have the same potential, and the transparent electrode 2
The ion attracting DC power supply 11 is connected so that the ion collector plate 12 has a negative potential.

According to this configuration, the positive ions 8 generated between the phosphor layer 3 and the grid 9 are transferred to the ion collector plate 12.
, the number of positive ions 8 colliding with the electron beam source 4 and the phosphor layer 3 decreases. The voltage of the ion attraction DC power supply 11 is set to a voltage sufficiently lower than the voltage of the acceleration DC power supply 6 so as not to disturb the progress of the electrons 7 from the electron beam source 4.

(Embodiment 4) In this embodiment, as shown in FIG. 4, the shape of the grid 9 in Embodiment 1 is changed. That is, a hemispherical diffusion portion 9a that is convex in a direction away from the electron beam source 4 is formed in a portion of the grid 9 that faces the electron beam source 4. If the grid 9 having such a shape is used, the electrons 7 emitted from the electron beam source 4 will spread by passing through the diffusion part 9a, and the phosphor layer will be The ratio of the irradiation area of 4 can be increased,
Although the electron beam source 4 with a small emission area is used, the emission area can be made large.

[0020]

As described above, according to the structure of claim 1, a grid connected to the same potential as the transparent electrode is disposed near the electron beam source between the electron beam source and the phosphor layer. Therefore, no electric field is formed between the phosphor layer and the grid, and less of the ionized residual gas generated inside the vacuum chamber is accelerated toward the electron beam source. . As a result, damage to the electron beam source due to collision of positive ions in the residual gas with the electron beam source can be suppressed.

According to the structure of claim 2, a grid set at a positive potential with respect to the electron beam source and the transparent electrode is disposed near the electron beam source between the electron beam source and the phosphor layer. Therefore, positive ions generated between the phosphor layer and the grid can be prevented from diffusing into the electric field formed between the transparent electrode and the grid, compared to the structure of claim 1. This has the advantage of further increasing the effect of suppressing damage to the electron beam source.

According to the structure of claim 3, a grid set to a positive potential with respect to the electron beam source is arranged near the electron beam source between the electron beam source and the phosphor layer, and the grid and the phosphor layer are arranged at a positive potential with respect to the electron beam source. An ion collector plate set at a negative potential with respect to the transparent electrode is installed at a position that does not impede the irradiation of the electron beam to the phosphor layer. This has the advantage that recombination of positive ions can be promoted, and the effect of suppressing damage to the electron beam source is higher than that of the structures of claims 1 and 2.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing Example 1.

FIG. 2 is a schematic cross-sectional view showing Example 2.

FIG. 3 is a schematic cross-sectional view showing Example 3.

FIG. 4 is a schematic cross-sectional view showing Example 4.

FIG. 5 is a schematic cross-sectional view showing a conventional example.

[Explanation of symbols]

1 Glass container 2 Transparent electrode 3 Phosphor layer 4. Electron beam source 5 DC power supply for cathode 6 DC power supply for acceleration 7 Electron 8 Positive ions 9 Grid 10 DC power supply for diffusion prevention 11 DC power supply for ion suction 12 Ion collector plate

Claims (3)

[Claims] Claim 1: A field emission type electron beam source and a transparent electrode placed opposite to the electron beam source and set at a positive potential with respect to the electron beam source are connected by irradiation with electrons emitted from the electron beam source. In a light-emitting element placed in a vacuum container with a light-emitting phosphor layer in between, a grid connected to the same potential as the transparent electrode is arranged near the electron beam source between the electron beam source and the phosphor layer. A light emitting element characterized by: 2. A field emission type electron beam source and a transparent electrode placed opposite to the electron beam source and set at a positive potential with respect to the electron beam source are connected by irradiation with electrons emitted from the electron beam source. In a light-emitting element placed in a vacuum container with a luminescent phosphor layer in between, a transparent electrode is placed near the electron beam source between the electron beam source and the phosphor layer and set at a positive potential with respect to the electron beam source and the transparent electrode. A light emitting element characterized by having a grid arranged therein. 3. A field emission type electron beam source and a transparent electrode placed opposite to the electron beam source and set at a positive potential with respect to the electron beam source are connected by irradiation with electrons emitted from the electron beam source. In a light-emitting element placed in a vacuum container with a light-emitting phosphor layer in between, a grid set at a positive potential with respect to the electron beam source is placed near the electron beam source between the electron beam source and the phosphor layer. A light-emitting element characterized in that an ion collector plate set at a negative potential with respect to the transparent electrode is provided between the grid and the phosphor layer at a position that does not impede irradiation of the electron beam to the phosphor layer.