JPH04282540A - Plane type image display device - Google Patents

Abstract

PURPOSE:To improve emitting intensity of light by increasing intensity of an electron beam to an anode from a cathode of a field emission type plane display. CONSTITUTION:An electron source, formed on a base body 11, is constituted of electron sources 12 to 15 of plurality of orders, and an electron from a cathode 23 is amplified by stages in each electron source 12 to 15. As a result, a strong electron beam can be irradiated to an anode 17, and emitting intensity of light of a light emitting material layer 35 can be increased.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat image display device, and more particularly to a flat image display device in which a light emitter emits light by electron beams from a plurality of electron sources.

0002

[Prior Art] CRTs in currently mainstream television receivers
Planar image display devices are being considered as alternative image display devices, and examples of such planar image display devices include liquid crystal displays (LCDs), electroluminescent devices (ELDs), and plasma display devices ( In addition, field emission type image display devices are also attracting attention in terms of screen brightness. Here, to briefly explain the field emission type image display device, a conical cathode made of molybdenum or the like with a diameter of 1.0 microns or less formed on a substrate using a semiconductor manufacturing process is used as an emission source. A plate-shaped gate electrode is formed on the tip side of the cathode, and has a hole corresponding to each cathode. The gate electrode is separated from the tip of the cathode, and a high voltage is applied between the two to generate field emission, and an electron beam is extracted from the cathode. Then, by irradiating this electron beam onto a light emitting body (phosphor) arranged on the back surface of the anode, a desired screen is displayed. Such field emission type image display devices are described in, for example, US Pat. No. 3,665,241 and Japanese Patent Laid-Open No. 1-294336.

FIG. 2 is a cross-sectional view of an example of a conventional field emission type image display device. A plurality of pointed cathodes 102 are arranged and formed on a base 101 . A gate electrode 104 is formed on the base 101 with an insulating film 103 interposed therebetween. Electrons are extracted by the voltage applied between the gate electrode 104 and the cathode 102. This gate electrode 104 has a hole 104a on the cathode 102, and the gate electrode 104 has a hole 104a on the cathode 102.
The electron beam from 2 passes through the hole 104a. and,
A planar anode 105 facing the base 101 to which a high voltage is applied is irradiated with the electron beam, and the electrons reach the light-emitting layer 106 on the back surface of the anode 105, causing the light-emitting layer 106 to emit light.

0004

[Problems to be Solved by the Invention] However, in such a field emission type image display device, the point-shaped cathode 1
The electron beam emitted from the electron beam 02 is easily scattered, and the emission intensity in the light emitter layer 106 is not sufficient. Therefore, new technical ingenuity was needed to form a brighter screen.

SUMMARY OF THE INVENTION In view of the above technical problems, the present invention aims to provide a flat image display device that uses an electron source that emits a powerful electron beam to improve the luminous intensity of a light emitter. do.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the flat image display device of the present invention includes a base, a plurality of electron sources disposed on the base, and a vacuum space for the electron sources. The electron source has a plurality of electron sources, and each electron source amplifies electrons one after another. It is characterized by irradiating a light emitting body.

[0007]

[Operation] The electron source of the flat image display device of the present invention is composed of secondary or higher order electron sources, and each electron source amplifies and emits electrons. Therefore, a large amount of electrons are finally emitted from the electron source, and the emission intensity of the light emitter is improved.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described with reference to the drawings. The flat image display device of this embodiment includes a plurality of electron sources, and can emit a large amount of electrons to irradiate the light emitting layer.

FIG. 1 is a schematic cross-sectional view of the flat image display device of this embodiment. On the base 11, primary to quaternary electron sources 12 to 15 are formed in a hierarchical structure. These primary electron sources to quaternary electron sources 12 to 15 are arranged such that odd-numbered electron sources 12 and 14 and even-numbered electron sources 13 and 15 are distributed across a vacuum space 16.
They are provided so as to face each other with the two sides in between. These primary electron sources to quaternary electron sources 12 to 15 are arranged so that the order increases from the base 11 side toward the anode 17 made of an aluminum film on the odd-numbered side and the even-numbered side, respectively.

The primary electron source 12 has a cathode 23 made of a metal such as molybdenum or tungsten sandwiched between interlayer insulating films 21 and 22 made of a silicon oxide film or the like. Electrically, the cathode 23 is grounded. The tip 23a of the cathode 23 has sawtooth-like peaks and valleys.
It is desirable to concentrate the electric field. The tip 23a side of the cathode 23 is open, and electrons are emitted from the opening 24. Extraction electrodes 25a and 25b are provided at the portion where the opening 24 connects to the vacuum space 16.
is coming. By applying a required extraction voltage to the extraction electrodes 25a and 25b, electrons are extracted from the cathode 23, and the primary electrons I1 are introduced into the vacuum space 16.

A secondary electron source 13 faces the primary electron source 12 with a vacuum space 16 in between, and is connected to a substrate 11 and an anode 17.
The position in between is located slightly closer to the anode 17 than the primary electron source 12. Secondary electron source 1
3 is an electron source layer 2 made of cesium oxide, magnesium oxide, etc.
7 is sandwiched between interlayer insulating films 26 and 28. A required positive voltage is applied to this electron source layer 27. A primary electron source 12 is provided on the surface of the electron source layer 27 on the vacuum space 16 side.
is irradiated with primary electrons I1 from . As a result, secondary electrons I2 are amplified and emitted from the electron source layer 27.

The tertiary electron source 14 faces the secondary electron source 13 with a vacuum space 16 in between, and is formed further above the primary electron source 12 on the substrate 11, that is, closer to the anode 17. The tertiary electron source 14 is located closer to the anode 17 than the secondary electron source 13 is. This tertiary electron source 14 includes an electron source layer 30 made of cesium oxide, magnesium oxide, etc., and an interlayer insulating film 29,
It has a structure sandwiched by 31. A higher voltage is applied to the electron source layer 30 of the tertiary electron source 14 than to the electron source layer 27 of the secondary electron source 13. The surface of the electron source layer 30 on the vacuum space 16 side is irradiated with secondary electrons I2 from the secondary electron source 13. Therefore, from the electron source layer 30 of the tertiary electron source 14, tertiary electrons I3 are amplified based on the secondary electrons I2.
is emitted towards the vacuum space 16.

The quaternary electron source 15 is located in the vacuum space 16.
It is arranged on the side of the secondary electron source 13 and faces the tertiary electron source 14 across the vacuum space. Electron source layer 27 of secondary electron source 13
The quaternary electron source 1 is placed on the interlayer insulating film 28 formed on the top of the
An electron source layer 32 made of cesium oxide, magnesium oxide, etc. of No. 5 is formed. Electron source layer 3 of this quaternary electron source 15
The position No. 2 is located closer to the anode 17 than the position of the tertiary electron source 14. An interlayer insulating film 33 is formed on the anode 17 side of the electron source layer 32, and the electron source layer 32 is sandwiched between the interlayer insulating films 28 and 33. This quaternary electron source 15
A voltage higher than that applied to the electron source layer 30 of the tertiary electron source 14 is applied to the electron source layer 32 of the tertiary electron source 14 . Therefore, in this quaternary electron source 15 as well, as in the tertiary electron source 14 and the secondary electron source 13, the surface of the electron source layer 32 on the vacuum space 16 side has three
The tertiary electrons I3 from the secondary electron source 14 are irradiated, and the 4
Amplified quaternary electrons I4 are emitted from the electron source layer 32 of the secondary electron source 15 toward the vacuum space 16.

A gate electrode 34 is arranged on the anode 17 side of the interlayer insulating film 33 and the interlayer insulating film 31. The gate electrode 34 is an electrode that controls the irradiation of the anode 17 with the quaternary electrons I4 by an electric field formed by the gate electrode, and when a high voltage is applied, the anode 17 is irradiated with the quaternary electrons I4. , when a low voltage is applied, the anode 17 is not irradiated with the quaternary electrons I4. This gate electrode 34 is formed to have an opening 37 that opens on an extension line toward the anode 17 side of the vacuum space 16 where the plurality of electron sources 12 to 14 face. For example, when electron sources consisting of a plurality of electron sources 12 to 14 are arranged in a two-dimensional matrix on the base 11, the openings 37 are also arranged in a two-dimensional matrix corresponding to their positions.

The anode 17 is connected to the gate electrode 34.
are arranged via a vacuum space 38 at a distance W. The anode 17 is an aluminum thin film having a surface parallel to the main surface of the base 11, and a high voltage is applied thereto. This anode 17
The thickness is, for example, about 100 angstroms. Electrons from the electron source reach the anode 17 in response to the electric field generated by the thin anode 17, and reach the light emitting layer 35 on the back surface thereof. The light emitting layer 35 formed on the opposite side of the base 11 of the anode 17 is bombarded with a large amount of electron beams greatly amplified by the multi-order electron sources 12 to 15, and emits intense light. A front panel glass 36 is formed on the surface of the light emitter layer 35 opposite to the anode 17, and an image generated by the light emitted from the light emitter layer 35 is displayed through the front panel glass 36.

In the flat image display device of this embodiment having such a structure, the secondary electron source 1 is connected to the primary electron source 12.
3 is supplied with a high voltage of about 50 to 100 V, the tertiary electron source 14 is supplied with a high voltage of about 50 to 100 V to the secondary electron source 13, and the quaternary electron source 15 is supplied with a high voltage of about 50 to 100 V to the secondary electron source 13.
4, a high voltage of about 50 to 100V is supplied. In this way, by applying a stepwise high voltage to each electron source, the electrons are amplified by each electron source and are distributed in the vacuum space 16.
is gradually sent to the anode 17 side. The energy of the electrons at this time is about 50 to 100 eV. Electrons emitted from the quaternary electron source 15 are emitted to the anode 17 according to the voltage of the gate electrode 34. For example, since each electron source can intensify electrons ten times or more, the quaternary electrons I4 emitted from the quaternary electron source 15 are made into a sufficiently amplified and powerful electron beam. Therefore, the light-emitting layer 15 can emit light with extremely high brightness, and a clear image can be displayed.

In the above-described embodiment, the arrangement of the plurality of electron sources is divided across the vacuum space 16, and the anode 17
Although the arrangement is such that the order gradually increases toward the side, the arrangement is not limited to this, and it is also possible to arrange multiple order electron sources in a plane, in which the electrons are amplified in an arc. , it is also possible to have a structure in which the anode is finally irradiated. Further, in this embodiment, up to a fourth order electron source is used, but the number is not limited to this, and orders such as third order, fifth order, sixth order, . . . may be used.

[0018]

Effects of the Invention As described above, the flat image display device of the present invention has a plurality of electron sources, and each time an electron is emitted from a lower order electron source to a higher order electron source, the electrons are amplified. Therefore, it is possible to irradiate the light emitting body with an extremely powerful electron beam, and sufficient light emission intensity is obtained, resulting in a clear image being displayed.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an example of a flat image display device of the present invention.

[Fig. 2] A schematic cross-sectional view of an example of a conventional flat image display device.

[Explanation of symbols]

11...Base 12...Primary electron source 13...Secondary electron source 14...Third electron source 15... Quaternary electron source 16,38...vacuum space 17...Anode 23...Cathode 27, 30, 32...electron source layer 34...Gate electrode 35... Luminous layer 37...Opening

Claims (1)

[Claims] Claim 1: A base body, a plurality of electron sources disposed on the base body, an electrode facing the electron source through a vacuum space, and a light emitting body provided on the opposite side of the electrode from the base body. 1. A flat image display device comprising a plurality of electron sources, each of which has a plurality of order electron sources, and each electron source amplifies electrons one after another and irradiates the light-emitting body with the electrons.