JP3211271B2 - Light emitting element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device such as a light emitting cell of a graphic fluorescent display tube and a large display device and a light source, and more particularly to a light emitting device using a field emission device.

[0002]

2. Description of the Related Art FIG. 6 shows an example of a conventional light emitting device using a field emission device. The field emission device 101 is provided on the cathode substrate 100. That is, the cathode electrode 102, the insulating layer 103, and the gate electrode 104 are stacked on the cathode substrate 100. A hole and an opening are formed in the insulating layer 103 and the gate electrode 104 by etching, and a cone-shaped emitter 105 is formed on the cathode electrode 102 in the hole of the insulating layer 103.
Are formed. An anode electrode 106 made of ITO is provided on the anode substrate 106 facing the cathode substrate 100.
7 is provided, and a phosphor 108 is attached to the anode electrode 107 to form an anode 109.

A predetermined voltage is applied to the anode 109, the cathode electrode 102 is scanned on the cathode side, and a selection signal is applied to the gate electrode 104 to select the field emission element 101 at a desired position. As a result, the phosphor 108 of the anode 109 located at a position facing the selected field emission element 101 is selectively illuminated and displayed.

[0004]

The above-mentioned conventional light emitting device has the following problems. First, since the cathode and the anode are close to each other, a discharge occurs when a high voltage is applied to the anode 109. For this reason, in general, the anode voltage must be 1 kV or less, and high-luminance display cannot be performed.

Next, in order to perform color display, a sulfide-based phosphor which is a phosphor having high luminous efficiency even at a low voltage has to be used. However, this phosphor has a problem in that it is decomposed by the excitation of excited electrons having energy equal to or higher than a certain value, contaminating the emitter and reducing the emission.

Next, since the cathode and the anode are directly opposed to each other, when the anode electrode is common, so-called leakage light emission is apt to occur due to electrons colliding with the pixel next to the pixel to emit light, and the crosstalk characteristic is reduced. There was a problem that it was not good.

An object of the present invention is to provide a light emitting device using a field emission device capable of realizing a high-luminance color display with little leakage light emission.

[0008]

A light emitting device according to the present invention comprises a cathode substrate, a field emission device having an emitter and a gate, provided on the cathode substrate, and a control electrode provided to face the field emission device. When the anode substrate facing the cathode substrate across the control electrode, the light-emitting element comprising an anode having a phosphor provided on the anode substrate, the control electrode and the cathode substrate
By the pillar material erected on each inner surface of the anode substrate
The control electrode is formed of a metal mesh corresponding to each pixel constituting the anode.
The opening is formed.

Further, according to the present invention, the invention according to claim 1 is provided.
In the optical element, the aperture ratio of the metal mesh is 80% or more.
It may be.

[0010]

The electrons are emitted from the selected field emission device on the cathode substrate. The electrons are converged at the opening of the control electrode and strike only the anode pixel on the anode substrate corresponding to the opening.

[0011]

FIG. 1 shows a light emitting device 1 according to a first embodiment. A strip-shaped cathode electrode 4 of a field emission device 3 is provided on a cathode substrate 2 made of a glass plate by photolithography. An insulating layer 5 is provided on the surface,
Further, a gate electrode 6 is provided in a direction orthogonal to the cathode electrode 4. Insulating layer 5 on the cathode electrode 4
A hole 7 is formed in the gate electrode 6 by photolithography, and a cone-shaped emitter 8 is provided in the hole 7. A plurality of emitters 8 (two in the first embodiment shown) are provided for one pixel.

An anode substrate 9 is provided above and parallel to the cathode substrate 2, and the two substrates 2 and 9 together with a side plate (not shown) constitute a box-shaped vacuum envelope.

On the inner surface of a light-transmitting anode substrate 9 such as a glass plate, a light-transmitting anode electrode 10 such as ITO is formed. On the anode electrode 10,
Phosphors r, g, and b emitting red, green, and blue light are attached to form a set of three pixels R, G, and B, and a metal back 11 made of aluminum is provided. An anode 11 which is a light emitting display unit is configured.

A control electrode 15 is provided between the field emission device 3 and the anode 12. The control electrode 15 is made of a metal plate, and has an opening 16 for each pixel of the anode 12. This control electrode 1
Reference numeral 5 denotes a pedestal 2 comprising a support member 18 erected on the inner surface of the cathode substrate 2 via a pedestal 17 and a support member 20 erected on the inner surface of the anode substrate 9 via a pedestal 19.
It is fixed by being sandwiched between both substrates 2 and 9 via 1 and 21.

Next, the operation of the above configuration will be described. An anode voltage of, for example, 2 kV or more is applied to the anode 12. In the field emission device 3, 0 or a negative cathode voltage is applied to the cathode electrode 4, and a gate voltage of 60 to 100 V is applied to the gate electrode 6 in synchronization with the application of the cathode voltage.
That is, electron emission is controlled by matrix driving of the cathode electrode 4 and the gate electrode 6, and pixel selection at the anode 12 is performed.

A voltage intermediate between the anode 12 and the cathode electrode 4, for example, a control voltage of 1 kV is applied to the control electrode 15. As a result, electrons emitted from the emitter 8 of the field emission device 3 pass through the opening 16 of the control electrode 15.
Are converged by passing through, and the passing aperture 16 collides with pixels R, G, and B facing each other to emit light.

FIG. 2 shows a light emitting device 30 according to a second embodiment. This light emitting element 30 has a larger size of one pixel than that of the first embodiment, and is used, for example, in a light emitting cell constituting a large-sized outdoor display device.

A fluorescent material 34 and a metal back 35 are provided on an anode electrode 33 on an anode substrate 32 to form an anode 31 which is a large-area pixel.

A control electrode 38 is provided between a pixel on the anode substrate 32 and a field emission element 37 on a cathode substrate 36 described later. Although not shown, the control electrode 3
8 is the same as that of the first embodiment. Control electrode 38
Is made of metal, and an opening of the anode substrate 32 facing the pixel is a metal mesh 39.

The cathode substrate 3 below the control electrode 38
A plurality of field emission devices 37 are formed on 6.
That is, the cathode electrode 40 is formed on the cathode substrate 36, and the insulating layer 41 and the gate electrode 42 are stacked thereon. A hole 43 is formed in each of the insulating layer 41 and the gate electrode 42, and a cone-shaped emitter 44 is formed on the cathode electrode 40 in the hole 43.

The field emission device 37 is of the Spindt type, and the divergence angle of the electron beam is about 30 °. Therefore, the area of the field emission device 37 may be smaller than the area of the metal mesh 39 of the control electrode 38. For example, if the diameter of the area where the field emission element 37 is disposed is x and the distance between the gate electrode 42 and the control electrode 38 is L, the diameter of the metal mesh 39 of the control electrode 38 is x + 2Ltan15 °.

The driving conditions of this embodiment are almost the same as those of the first embodiment. Next, the operation and effect of this embodiment will be described more specifically. In the structure of this embodiment, the aperture ratio is 80
% And a control electrode (Mesh Grid) using a metal mesh of not less than% in the opening of the control electrode 38 and a control electrode (No Grid) having a 10 mm square hole are fixed at a position of 4 mm from the cathode side to compare characteristics. Was performed. FIG.
Fig. 7 shows changes in the anode current with respect to the grid voltage. There is almost no change in the control electrode having a 10 mm square hole, which is substantially the same as that in a light emitting element having a large pixel without a grid. On the other hand, in a control electrode (mesh grid) having an opening of a metal mesh, the anode current increases in accordance with the grid voltage, and electrons from the cathode are converged by the mesh grid and reach the anode. Understand.

FIG. 4 shows a change in the area of the light emitting region (Spot Area) with respect to the grid voltage. According to this figure, it can be seen that the diffusion effect of the mesh grid works effectively.

FIG. 5 shows a change in anode current with respect to anode voltage when a mesh grid is used. From this figure, it can be seen that an almost stable anode current can be obtained for an anode voltage of 2 kV or more. This also indicates that the mesh grid works effectively as a screen grid for the anode voltage and prevents discharge.

[0025]

According to the light emitting device of the present invention, the control electrode is provided between the field emission device and the anode, and the control electrode has an opening corresponding to the pixel of the anode. Therefore, according to the present invention, the following effects can be obtained.

(1) Since a high voltage can be applied to the anode, it is possible to use a phosphor for high voltage excitation light emission.
The problem caused by the sulfide phosphor can be solved. (2) A full-color, high-luminance type light-emitting element can be formed. (3) Since the control electrodes are provided, electrons can be converged and diffused, and only the pixels to be selected can emit light uniformly. (4) A flat display that is thinner, lower in power consumption, higher in quality, lower in distortion and more resistant to vibration than in a CRT can be realized.

[Brief description of the drawings]

FIG. 1 is a sectional view of a first embodiment.

FIG. 2 is a sectional view of a second embodiment.

FIG. 3 is a graph of an experimental result showing an effect of the second embodiment.

FIG. 4 is a graph of an experimental result showing an operation and effect of the second embodiment.

FIG. 5 is a graph of an experimental result showing the operation and effect of the second embodiment.

FIG. 6 is an exploded perspective view of a conventional light emitting device.

[Explanation of symbols]

 Reference Signs List 1,30 Light emitting element 2,36 Cathode substrate 3,37 Field emission element 6,42 Gate electrode 8,44 Emitter 9,32 Anode substrate 12,31 Anode 15,38 Control electrode 16 Opening 39 Metal mesh as opening r , G, b, 34 phosphor

Continued on the front page (72) Inventor Tatsuo Yamaura 629 Oshiba, Mobara-shi, Chiba Prefecture Inside Futaba Electronics Co., Ltd. (72) Inventor Hisashi Nakada 629 Oshiba, Mobara-shi, Chiba Prefecture Futaba Electronics Corporation (72) Invention Applicant Kazuyoshi Otsu 629 Oshiba, Mobara-shi, Chiba Prefecture Futaba Electronics Co., Ltd. (72) Inventor Masateru Taniguchi 629 Oshiba, Mobara-shi, Chiba Prefecture Futaba Electronics Industry Co., Ltd. (56) References JP-A-2-299137 (JP, A) JP-A-3-152838 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 63/06 H01J 1/46 H01J 31/12

Claims (2)

(57) [Claims] 1. A cathode substrate, a field emission device having an emitter and a gate, provided on the cathode substrate, a control electrode provided to face the field emission device, and the cathode substrate sandwiching the control electrode A light emitting element comprising an anode substrate facing the anode substrate and an anode having a phosphor provided on the anode substrate, wherein the control electrode is
The cathode substrate and the anode substrate are erected on respective inner surfaces thereof.
A metal plate sandwiched between the supporting members, and the control electrode has a metal member corresponding to each pixel constituting the anode.
A light-emitting element having an opening formed of a brush . 2. The method according to claim 1, wherein the metal mesh has an aperture ratio of 80% or more.
Emitting element of a claim 1, wherein.