JPH04286853A - Electroluminescent device - Google Patents

Abstract

PURPOSE:To heighten the luminescence brightness by taking luminescence out of the side, to which electrons are radiated, of a phosphor layer. CONSTITUTION:An electric field radiating-type electron beam source 1 and a collector plate 2 are set to face each other. An open window 5 to transmit electrons radiated from the electron beam source 1 is formed in the center part of the collector 2. A d.c. electric power source V2 is so connected with the electron beam source 1 and the collector plate 2 as to connect the anode with the collector plate 2. A phosphor layer 3 is formed in the side, which is on the opposite to the electron beam source 1, of the collector plate 2. After the electrons radiated from the electron beam source 1 pass the open window 5, they are drawn to the collector plate 2 and thus the phosphor layer 3 emits luminescence.

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 in which a phosphor layer is excited by electrons emitted from a field emission type electron beam source to emit light.

0002

[Prior Art] Conventionally, a field emission type electron beam source is disposed in a container such as a glass container that is sealed with a vacuum inside, and is excited by electrons emitted from the electron beam source to emit light. A light emitting element is provided in which a phosphor layer is placed in front of an electron beam source. In this type of light emitting element, a transparent electrode is formed on the inner peripheral surface of a container facing an electron beam source, and a phosphor layer is formed on the surface of this transparent electrode. The transparent electrode is set at a positive potential with respect to the electron beam source, and electrons emitted from the electron beam source are accelerated toward the transparent electrode, reach the phosphor layer, and emit light. A light emitting element having such a configuration is expected to be used as a display element because it is small and has low loss.

0003

[Problem to be Solved by the Invention] By the way, when a phosphor layer is irradiated with electrons, the probability of being irradiated with electrons increases as the area closer to the surface of the phosphor layer increases. Considering the distribution, it is thought that the amount of light emitted increases toward the surface. In the light-emitting element with the above configuration, the surface that utilizes the light generated in the phosphor layer (hereinafter referred to as the observation surface) is the opposite side to the surface on which the phosphor layer is irradiated with electrons, so it mainly fluoresces. Light generated on the surface side of the body layer passes through the phosphor layer and is used. As a result, a problem arises in that the amount of attenuation of light increases, leading to a decrease in luminous efficiency.

The present invention aims to solve the above-mentioned problems, and provides a light emitting element with higher luminous efficiency than the conventional one.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a field emission type electron beam source and a field emission type electron beam source arranged in front of a radiation surface of the electron beam source so as to be substantially parallel to the radiation surface. The collector plate includes a collector plate set at a positive potential with respect to the electron beam source, and a phosphor layer formed on the surface of the collector plate opposite to the electron beam source, and the collector plate is configured to receive radiation from the electron beam source. An aperture window through which electrons can pass is provided in a position corresponding to the front of the emission surface of the electron beam source, and the phosphor layer is excited by electrons emitted from the electron beam source and attracted to the collector plate after passing through the aperture window. This is done so that it emits light.

[0006]

[Operation] According to the above configuration, the electrons emitted from the electron beam source pass through the aperture window of the collector plate, and then are irradiated onto the phosphor layer formed on the surface of the collector plate, causing the phosphor layer to emit light. Since the surface that utilizes the light generated in the phosphor layer is the same surface that irradiates the phosphor layer with electrons, the light generated on the surface of the phosphor layer is transmitted through the phosphor layer. The light emission brightness is higher than before.

[0007]

[Example] (Example 1) In this example, as shown in FIG. 1, a field emission type electron beam source 1 is provided, a collector plate 2 is arranged in front of the emission surface of the electron beam source 1, In addition, collector board 2
A transparent electrode 4 is placed in front of the. A phosphor layer 3 is formed on the surface of the collector plate 2 facing the transparent electrode 4 .

The electron beam source 1 has a flat gate having a large number of through holes, and conical emitters arranged at positions corresponding to the respective through holes of the gate. This electron beam source 1 has a strong electric field (for example,
108 V/m or higher), electrons are emitted from the emitter and taken out through the through hole of the gate. The collector plate 2 is formed into a circular shape using stainless steel, and a circular opening window 5 is formed in the center at a portion corresponding to the radiation surface of the electron beam source 1. The size of the opening window 5 is set so that electrons emitted from the electron beam source 1 can pass therethrough. The phosphor layer 3 is formed by depositing a low-speed electron beam-excited phosphor on the collector plate 2. Further, the transparent electrode 4 is made of ITO (i) on a glass plate or the like.
It is formed by depositing a conductive film such as ndium tin oxide. The electron beam source 1, the collector plate 2, and the transparent electrode 4 are housed in a container such as a glass container that is evacuated and sealed. Further, the transparent electrode 4 may be one in which a transparent conductive film is formed on the inner peripheral surface of the container.

A DC power source V1 for electron beam emission is connected between the gate electrode G and emitter electrode E of the electron beam source 1, with the gate electrode G serving as a positive electrode. This DC power supply V
1, the above-mentioned strong electric field is formed between the gate and the emitter and electrons are emitted. Further, an accelerating DC power supply V2 is connected between the gate electrode G of the electron beam source 1 and the collector plate 2, with the collector plate 2 as the positive electrode, and the electrons emitted from the electron beam source 1 are accelerated and opened. window 5
The voltage is set so that the light passes through and is attracted to the front side of the collector plate 2. Further, a reflection DC power supply V3 is connected between the gate electrode G and the transparent electrode 4, with the gate electrode G as the positive electrode, and the electrons transmitted through the aperture window 5 receive a repulsive force from the transparent electrode 4 and are sent to the collector plate. 2 (arrows in the figure indicate electron orbits).

In the above configuration, the radiation surface of the electron beam source 1 is 1 mm in diameter, the collector plate 2 is a disk with a diameter of 10 mm, the opening window 5 is a circular hole with a diameter of 2 mm, and the distance between the electron beam source 1 and the collector plate 2 is 2mm, DC power supplies V1, V2, V3
When the voltages were set to 100 V, 100 V, and 20 V, respectively, electrons were generated by field emission, and an emission current of about 50 μA was generated. The generated electrons pass through the aperture window 5
After passing through the transparent electrode 2 and reaching the front of the collector plate 2,
It moved backward toward the phosphor layer 3 due to the repulsive force from the phosphor layer 3, causing the phosphor layer 3 to emit light.

According to the above structure, the light generated on the surface of the phosphor layer 3 is extracted without passing through the phosphor layer 3, so that the luminance is higher than that of the conventional device. (Example 2) In this example, as shown in FIG.
A phosphor layer 3' is provided separately from the collector plate 2. Further, an accelerating DC power source V4 is connected between the gate electrode G of the electron beam source 1 and the transparent electrode 4 so that the transparent electrode 4 serves as a positive electrode. The area of the phosphor layer 3' is set to be slightly larger than the aperture window 5 and smaller than the phosphor layer 3.

Here, for example, the phosphor layer 3 is formed of a blue phosphor, the phosphor layer 3' is formed of a green phosphor, and each DC power source V1, V2, V4 is
When the voltages were set to 00V, 0V, and 100V, most of the emission current flowed through the transparent electrode 4, and green light was emitted. Further, when the DC power sources V1, V2, and V4 were set to 100 V, 100 V, and -20 V, respectively, most of the emission current flowed through the collector plate 2 and emitted blue light.

As exemplified above, in the configuration of this embodiment, the phosphor layers 3 and 3' are formed of phosphors of different colors, and the color of the emitted light is changed by controlling the voltage of each DC power source V2, V4. It is possible to do so. (Embodiment 3) In this embodiment, as shown in FIG. 3, the collector plate 2 is divided into a first electrode plate 2a and a second electrode plate 2b. A slit-shaped opening window 5 is formed in between. Here, the first electrode plate 2a and the second electrode plate 2b are electrically separated, and phosphor layers 3a and 3b are respectively deposited thereon. Accelerating DC power supplies V5 and V6 are connected between the first electrode plate 2a and the second electrode plate 2b and the gate electrode G of the electron beam source 1, respectively, with the gate electrode G as a negative electrode. Further, the transparent electrode 4 has a phosphor layer 3' formed in its center, as in the second embodiment.

Here, for example, the first electrode plate 2a and the second
It is assumed that the width of the opening window 5 between the electrode plate 2b and the electrode plate 2b is 2 mm, and that the phosphor layer 3a is made of a blue phosphor, the phosphor layer 3b is made of a red phosphor, and the phosphor screen layer 3' is made of a green phosphor. In this configuration, each DC power source V1, V4, V5, V6
were set to 100 V, 100 V, 0 V, and 0 V, respectively, most of the emission current flowed through the transparent electrode 4, and the light emitting element emitted green light. In addition, each DC power supply V1, V4, V5, V6 is 100V,
When the voltages were set to -20V, 100V, and 0V, most of the emission current flowed through the first electrode plate 2a, and the light emitting element emitted blue light. Furthermore, each DC power supply V1, V
4, V5, and V6 at 100V and -20V, respectively.
When the voltages were set to 0V and 100V, most of the emission current flowed through the second electrode plate 2b, and the light emitting element emitted red light.

According to the above configuration, each DC power supply V
By controlling the voltages of V4, V5, and V6, it is possible to select three emitted colors, and the range of color control can be further expanded compared to the second embodiment.

[0016]

Effects of the Invention As described above, in the present invention, the electrons emitted from the electron beam source pass through the aperture window of the collector plate, and then are irradiated onto the phosphor layer formed on the surface of the collector plate, so that the phosphor layer The layer is made to emit light, and the surface that uses the light generated in the phosphor layer is the same surface that is irradiated with electrons to the phosphor layer, so the light generated on the surface of the phosphor layer becomes fluorescent. It is used without passing through the body layer, and has the advantage that the luminance is higher than in the past.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing Example 1. FIG.

FIG. 2 is a schematic perspective view showing a second embodiment.

FIG. 3 is a schematic perspective view showing Example 3.

[Explanation of symbols]

1　Electron beam source 2 Collector board 3 Phosphor layer 4 Transparent electrode 5 Opening window

Claims (1)

[Claims] 1. A field emission type electron beam source; a collector plate disposed in front of a radiation surface of the electron beam source so as to be substantially parallel to the radiation surface and set at a positive potential with respect to the electron beam source; A phosphor layer is formed on the surface of the collector plate opposite to the electron beam source, and the collector plate has an aperture window in front of the emission surface of the electron beam source through which electrons emitted from the electron beam source can pass. 1. A light-emitting element, characterized in that the phosphor layer is excited by electrons emitted from an electron beam source, transmitted through an aperture window, and then attracted to a collector plate to emit light.