JPH03187138A - Image display device - Google Patents

Abstract

PURPOSE:To improve an image quality, and to achieve the long-life of an image display device by irradiating the radiation electron flow emitted from the point of a cathode, on a phosphor layer on a transparent conductive film, in such a way that an electron is amplified, through the electron multiplier plate provided between a gate electrode and the transparent conductive film. CONSTITUTION:Pass holes 30 are regularly arranged between a gate electrode 25 and a transparent conductive film 28 as an anode, while an electron multiplier plate 31 is formed out of a material having a characteristic as a secondary electron multiplier. The radiation electron flow emitted from a cathode point 26 is irradiated on a phosphor layer 29 on the transparent conductive film 28, by amplifying electron. The irradiation current required for each cathode point 26 to obtain necessary display luminance is reduced thereby, and the electron flow that runs into the gate electrode 25 can be reduced, whereby the degree of damage given to the cathode point 26 due to the bombardment of gas ions can be reduced. The working life can be expected to be longer, and an image of good quality can thus be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image display device that irradiates a phosphor with a stream of radiated electrons emitted from a cold cathode and displays an image using the light from the phosphor. It is.

[Conventional technology]

Figure 2 shows IEEE Transactions of Electron Devices.
actions of Electron Device
es, 36 [1] (1989-1), C,A,
5pindt, “Field-Enitter A
rraysApplied to Vacuun Fl
uorescent Display” P, 225-
227) is a configuration diagram showing a conventional image display device described in Japanese Patent No. 227).

In the conventional device shown in FIG. 2, a base electrode (cathode) 3 is formed on a St substrate 1 covered with oxide M2, and a gate electrode f#! 5 is formed. Several tens to hundreds of electrode holes 6 are formed in the gate electrode 5, and a cathode tip (not shown) formed in the shape of a conical projection is formed in the electrode hole 6.

On the other hand, a transparent front substrate 8 placed opposite to the substrate 1 with a spacer 7 in between has an IT
The device has a transparent conductive film (anode) made of a transparent conductive film (anode), and three types of phosphor layers 10 having different fluorescent colors are formed thereon.

Here, Figure 3 is from the Journal of Applied Physics.
l+ysics47 [12] (1976-12
) (US), Helican In5tituteo
f Physics, C, 8, 5pindt,
”Physical properties of
thin-filtm field 0IliSSiO
n CathOdeS withnolybdcnun
2 is a cross-sectional view showing the cathode tip portion of the image display device described in ``Cones'', P, 5248-5263).The cathode tip shown here is indicated by the reference numeral 6, the details of which are not shown in FIG. As shown in FIG. 3, in such an apparatus, the St substrate 1
1, an insulating film 12 made of SiO□ is formed, and a cathode tip 13 in the shape of a conical projection is formed in the center of a cavity 12a of the insulating film 12. Furthermore, a gate electrode 14 having an electrode hole 14a surrounding the tip portion of the cathode tip 13 is provided on the insulator [12].

Then, in order to emit electrons from the cathode tip 13, 10
Applying a strong electric field of about 7V/am, the cathode tip f4A13
emit an electron current from the transparent conductive film (
The light is accelerated and aggregated by reference numeral 9 in FIG. 2 and irradiated onto the phosphor layer (reference numeral 10 in FIG. 2) to display an image.

On the other hand, Figure 4 shows the Procedures of the SI
D, 29/3. (1988), Hans, J.R.
ell, “The Achievement of
color in the 12-in, channel
el-multiplier CRT"P, 201-2
Planar type C incorporating the electron multiplier function board described in 05)
FIG. 5 is an external perspective view showing the RT, and FIG. 5 is a schematic sectional view showing an enlarged main part of FIG. 4. In this CRT, an electron beam emitted from an electron gun 21 is reflected by a primary deflection electrode 22, an inversion/convergence lens 23, and a secondary deflection electrode 24, and after being subjected to planar deflection control, the electron beam is multiplied. The electron flow incident on the function board 25 and multiplied by the electrons is an accelerated type f!, as shown in FIG. The light is extracted while being accelerated and converged by the light beam 26, deflected by the deflection electrode 27 for selecting the three primary colors, and irradiated onto the R (red), G (green), and B (blue) phosphors 29 on the front substrate 28.

[Problem to be solved by the invention]

However, in the conventional example shown in FIG. 2 and FIG.
Since a strong electric field on the order of /c+n is required, an extremely sharp tta tip is required. For this reason, damage caused by the impact of residual gas ions concentrates on a narrow area (sharp tip portion) of the cathode tip, resulting in a problem that the operational life of the cathode tip is shortened.

Furthermore, in the conventional example shown in FIGS. 4 and 5,
Although the volume of the display device is significantly reduced compared to a normal CRT, there is a problem that it cannot be made thinner than a liquid crystal, EL, or plasma display device.

Furthermore, it is necessary to individually converge and deflect the electron beam from one electron gun in order to select the three primary colors, which poses the problem of complicating the structure of the apparatus. Furthermore,
The deflection electrode has a relatively large capacitance (15 nF), and an excessive peak current of about 0.5 A is required for switching under the conditions of a deflection voltage of 70 V and a switching time of 2 to 3 μs, so a relatively large power drive circuit is required. There was a problem that required it.

Therefore, the present invention has been made to solve the problems of the prior art described above, and its objectives are to provide a system with a long operating life, a small and simple configuration, good image quality, and high reliability. An object of the present invention is to provide an image display device.

[Means to solve the problem]

An image display device according to the present invention includes an insulating substrate, a cathode provided on the insulating substrate, a #polar tip formed on the cathode in the shape of a protrusion having a sharp tip, and the cathode tip. a gate electrode formed to have an electrode hole surrounding the
a transparent substrate disposed opposite to the insulating substrate at a predetermined interval; an anode provided on a surface of the transparent substrate opposite to the cathode tip; and an anode provided on the anode and provided with the cathode tip. an image display device comprising: a phosphor layer that emits light in response to a radiant electron flow emitted from the anode to the anode;
An electron field@function plate is provided between the gate electrode and the anode to amplify the emitted electron flow from the cathode tip by means of a through hole having an inner surface having an electron amplification function.

[For production]

In the present invention, an electron multiplier plate is provided between the gate electrode and the anode to amplify the electron flow emitted from the cathode tip and irradiate the phosphor layer on the anode. In this way, the emission current required by each cathode tip to obtain the required display brightness can be lowered, thereby reducing the electron flow flowing into the gate electrode and further reducing the gas ion collisions. This can reduce the degree of damage to the cathode tip caused by

〔Example〕

The present invention will be explained below based on the illustrated embodiments.

FIG. 1 is a top view showing one embodiment of the image display device according to the present invention, and FIGS. 6(a) and (b) show an example of the hole arrangement of the electron multiplier function board 31 of the present embodiment. The plan view and FIG. 7 are cross-sectional views showing the electron multiplier function board 31 of this embodiment.

As shown in FIG. 1, in actual turning, the thickness of the SL substrate 21, which is the back substrate, is 0.5 to 1.5 mm.
A striped base electrode (negative 11i) 23 with a thickness of about 0.5 μm is provided on the upper surface of the insulating film 22 with a thickness of about 0 am, and an insulating film 2 with a thickness of about 0.5 to 1.5 μm is provided on the base electrode (negative 11i) 23 with a thickness of about 0.5 μm.
4. Striped gate electrodes 25 made of Mo and having a thickness of about 0.2 to 1.0 μm are sequentially provided. Also,
The insulating film 24 and the gate electrode 25 each have a diameter of 1.5 mm.
~3.0 μm cavity portion 24a and gate electrode hole 25a
There are several to hundreds of . Furthermore, each cavity 24a (electrode hole 25a) on the base electrode 23
Inside, one cathode tip 26 made of Mo is disposed with a curved radius of about 0.05 to 0.2 μm at the tip.

On the other hand, a front substrate 27 made of transparent glass is arranged opposite to the St substrate 21, and the cathode tip 2 of this front substrate 27 is disposed opposite to the St substrate 21.
A transparent conductive film 28 as an anode is provided on each of the six sides. Furthermore, R (red) is displayed on the transparent conductive film 28 by fluorescence.
Two phosphor layers that emit light of colors , G (green), and B (blue) are provided in a striped pattern.

In this embodiment, for example, there is a connection between the gate electrode @ 25 and the transparent conductive film 28 in FIG. 6(a) or FIG.
) are arranged in a regular array through holes 30 as shown in FIG.

This electron multiplier function board 31 is made of, for example, MgO, CS
It is made of a material having secondary electron multiplication characteristics such as 20. Further, an input side electrode 32 and an output side pole 33 are provided for forming an accelerating electric field for the electron flow passing through the through hole 30.

In this embodiment, as shown in FIG. 6(a), one pixel (here, pixel refers to the range displayed by the cathode tip located within one electrode hole) is provided in one through hole 30. In addition, as shown in FIG. 6(b), a plurality of through holes 30 can be made to correspond to one pixel, and the multiplication gain for each pixel can be averaged to reduce luminance variations between pixels. You can also.

Here, by setting the length of the through hole 30 (the length in the thickness direction of the electron multiplier function board 31) to several times to several tens of times the equivalent diameter of the through hole 30, the length can be set to several tens to several hundreds. A double multiplication gain can be achieved.

When displaying an image, an electric field is applied to the cathode tip #i26 by the gate electrode 25 to cause electron flow to be emitted from the cathode tip #i26.

Then, this radiated electron flow is incident on the through hole 30 of the electron multiplier function board 31 where a potential gradient is formed by the input side electrode 32 and the output side electrode 33. The electron flow incident here has an electron multiplication function and is multiplied by hitting the inner surface of the through hole 30, and is also accelerated and collected in the direction of the phosphor 29 by the transparent conductive film 28, and is irradiated onto the phosphor 29. The phosphor 29 is excited by the electron flow and outputs light of a predetermined color through the transparent electrode film 28 and the front substrate 27 to display an image.

As explained above, in this embodiment, the gate electrode 25 and the transparent conductive g! 28, an electron multiplier function board 31
The radiant electron current emitted from the cathode tip 26 is amplified and irradiated onto the phosphor layer 29 on the transparent conductive film 28 . By doing so, the radiation current required for each cathode tip f@26 to obtain the necessary display brightness can be significantly reduced from several tens of minutes to several hundred bones. The flow of electrons flowing into the gate electrode can be reduced. Therefore, by reducing the gate current, it is possible to reduce the burden on a drive circuit (not shown) for gate voltage control. Furthermore, by reducing the gate current, the voltage drop caused by the current flowing through the gate electrode can be reduced, and the brightness unevenness caused by this voltage drop can be reduced, so that image quality can be improved.

Furthermore, a reduction in the electric field at the cathode tip @26 means a reduction in the impact energy due to residual gas ions, and also a reduction in the electric field at the cathode tip f@26.
Since the radius of curvature of the cathode tip 26 can be expanded, the degree of damage to the cathode tip @26 due to gas ion collisions can be reduced, and the operating life of the device can be extended.

Further, according to this embodiment, as shown in FIG. 5, the surface of the phosphor layer 29 is set directly facing the electron multiplier function plate 31, and the conventional example shown in FIGS. No need for deflection am for RGB selection control, simplification of in,
The thickness can be reduced.

Incidentally, FIG. 8 is a sectional view showing another example of the electron multiplier function board. In this electron multiplier function board, electron holes are arranged in an insulating thin plate 61 such as 8102, and a semi-insulating film 62 having secondary electron multiplier properties such as MgO1C820 is formed on the inner surface of the hole. Further, @poles 63, 64 are provided for forming an accelerating electric field for the electron flow. In this embodiment as well, efficient electron multiplication can be performed as in FIG. 1.

FIG. 9 is a diagram illustrating the constituent countries of another embodiment of the present invention, and FIG. 10 is an explanatory diagram of the electron flow E of this embodiment. In the drawings, the same reference numerals are given to the components corresponding to the embodiment shown in FIG.

In this embodiment, a striped base electrode (cathode ) 23 with a thickness of 0.5 to 1
．． Insulating film 24 of about 5 μm, thickness 0.2 to 1. O)tm
Striped gate Th electrodes 25 made of Mo are sequentially provided. Further, the insulating FyA 24 and the gate electrode 25 each have a diameter of 1.5 to 3. Several to hundreds of cavity portions 24a and gate electrode holes 25a each having a size of approximately Oczm are provided. Further, in each cavity 24a (electrode hole 25a) on the base electrode 23, a plurality of cathode tips 26 made of Mo and having a curved radius of about 0.05 to 0.2 μm at the tip are arranged. .

On the other hand, a front substrate 27 made of transparent glass is arranged opposite to the Si substrate 21, and the cathode tip 2 of this front substrate 27 is disposed opposite to the Si substrate 21.
A transparent conductive film 28 as an anode is provided on the surface 6011. Furthermore, R(
A phosphor layer 29 that emits light of red (red), G (green), and B (blue) colors is provided in a striped pattern.

In this embodiment, a plurality of through holes 30, which are formed by communicating small chambers of random size and random shape, are arranged at random positions between the gate electrode 25 and the transparent conductor 1i28. , this hole allows the cathode tip 26 to
It is equipped with an electron multiplier function board 31 that amplifies the emitted electron flow from the radiated electron flow. This electron multiplier function board 31 is made of, for example, MgO
It is made of a material having a secondary electron multiplication property such as 1Cs20, and is manufactured by a known method such as mixing a foaming material with a thin plate having a secondary electron multiplication property and firing the mixture. In addition, an input side electrode 32 and an output side type @33 are used to form an accelerating electric field for the electron flow passing through the through hole 30.
In this embodiment, the opening area of the through hole 30 is set so as to collect a plurality of electron flows in the gate electrode hole 25a. Here, by setting the length of the through hole (the length in the thickness direction of the electron multiplier function board 31) to several times to several tens of times the equivalent diameter of the through hole 30, the length can be several tens to several hundred times larger. It is possible to achieve a multiplication gain of

When displaying an image, an electric field is applied to the cathode tip 26 by the gate electrode 25 to cause electron flow to be emitted from the cathode tip 26 in order to cause the cathode tip 26 to emit electrons.

Then, this radiation electron flow flows between the input side electrode 32 and the output side type t.
The light enters the through hole 30 of the electron multiplier function board 31 where a potential gradient is formed by if133. The incident electron flow here is multiplied by hitting the inner surface of the through hole 30, which has a random size and random shape and has an electron multiplication function, and is also accelerated in the direction of the phosphor 29 by the transparent conductive film 28 and aggregated. and irradiates the phosphor 29. The phosphor 29 is excited by the electron flow and outputs light of a predetermined color through the transparent type 28 and the front substrate 27 to display an image.

As explained above, in this embodiment, a plurality of through holes 30, which are formed by communicating small chambers of random size and random shape, are randomly formed between the gate electrode 25 and the transparent conductive film 28. The phosphor layer 2 on the transparent conductive v428 is equipped with an electron multiplier plate 31 configured to be arranged at a position that amplifies the emitted electron flow emitted from the cathode tip 26.
9 is irradiated. By doing so, the radiation current required for each cathode tip 26 to obtain the necessary display brightness can be significantly reduced from tens of minutes to hundreds of minutes, so that the gate electrode The flow of electrons flowing into the substrate can be reduced. Therefore, by reducing the gate current, it is possible to reduce the burden on a drive circuit (not shown) for gate voltage control. Furthermore, by reducing the gate current, the voltage drop caused by the current flowing through the gate electrode can be reduced, and the brightness unevenness caused by this voltage drop can be reduced, so that image quality can be improved.

Furthermore, the cathode tip r! Reducing the electric field of 1A26 means reducing the impact energy caused by residual gas ions, and also makes it possible to expand the radius of curvature of the cathode tip tIM26, so the degree of damage to the cathode tip 26 due to gas ion collisions can be reduced. The operating life of the device can be extended.

In addition, the electron multiplier function board 31, which has a plurality of through holes 30 arranged at random positions, which are formed by communicating small chambers of random size and random shape, is manufactured by mixing foaming materials and firing them. This is a simple method, and the manufacturing cost is lower than that of a regular arrangement of through holes.
The price of the device can be kept low.

Furthermore, one through hole does not correspond to one pixel (here, pixel refers to the area displayed by the cathode tip located within one electrode hole), but rather multiple through holes 30. can be made to correspond to one pixel, the multiplication gain of each pixel by the electron multiplier function board 31 is averaged, and it is possible to obtain good image quality with small luminance variations between pixels.

Further, according to this embodiment, as shown in FIG. 5, the surface of the phosphor layer 29 is set directly facing the electron multiplier function plate 31, and the conventional example shown in FIGS. It does not require a deflection mechanism for RGB selection control, simplifying the structure,
The thickness can be reduced.

Incidentally, FIG. 11 is a sectional view showing another example of the electron multiplier function board applied to the embodiment of FIG. 9. In this electron multiplier function board 41, electron holes are randomly arranged in a semi-insulating thin plate having secondary electron multiplication properties such as MgO, Cs2O, etc., and the electron flow passing through the holes is accelerated. give an electric field,
Electrodes 42 and 43 are provided on both sides of the electron multiplier plate 41.

Moreover, FIG. 12 is a sectional view showing still another example of the electron multiplier function board applied to the embodiment of FIG. 9.

In this electron multiplier function board, electron holes are randomly arranged in an insulating thin plate 51 made of, for example, SiO2, and a semi-insulating material having secondary electron multiplier properties, such as MgO1C820, is formed on the inner surface of the hole. fi 52 is provided, and electrodes 53 and 54 for forming an accelerating electric field for electron flow are also provided. In both the embodiments shown in FIG. 11 and FIG. 12, efficient electron multiplication can be performed in the same manner as in FIG. 9.

〔Effect of the invention〕

As explained above, in the present invention, an electron multiplier plate is provided to amplify the radiation electron flow emitted from the cathode tip and irradiate it to the phosphor layer on the transparent conductive film. The radiation current required at the tip is significantly reduced, and the electron flow flowing into the gate electrode is reduced, which reduces the burden on the drive circuit for gate voltage control and improves the reliability of the device. . Furthermore, by reducing the gate current, the voltage drop caused by the current flowing through the gate electrode can be reduced, and the brightness unevenness caused by this voltage drop can be reduced, so that image quality can be improved.

Furthermore, reducing the electric field at the cathode tip means reducing the impact energy caused by residual gas ions, and also makes it possible to expand the radius of curvature of the cathode tip, which reduces damage to the cathode tip due to gas ion collisions. The operating life of the device can be extended.

Further, since the phosphor layer surface is set directly opposite the electron multiplier function plate, there is no need for a deflection mechanism for RGB selection control, and the structure can be simplified and made thinner.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of an image display device according to the present invention, FIG. 2 is a block diagram showing an example of a conventional image display device, and FIG. 3 is a block diagram showing an example of a conventional image display device. The cross-sectional view shown in Figure 4 is a planar CR incorporating a conventional electron multiplier function board.
Figure 5 is an enlarged schematic sectional view of the main part of Figure 4. Figures 6 (a) and (b) are the hole arrangement of the electron multiplier plate in Figure 1. 7 is a cross-sectional view showing the electron multiplier function board of FIG. 1, and FIG. 8 is a plan view showing an example of the electron multiplier function board of FIG. 1. 9 is a block diagram showing another embodiment of the present invention, FIG. 10 is an explanatory diagram of electron flow in the embodiment of FIG. 9, and FIGS. 11 and 12 are the embodiment of FIG. 9. FIG. 3 is a sectional view showing another example of the electron multiplier function board in FIG. 21... St substrate 22... Insulating film 23... Base electrode (cathode) 24... Insulating film 24a... Cavity part 25... Gate electrode 25a... Gate electrode hole 26... Cathode tip 27...front substrate 28...transparent conductive film 29...phosphor layer 30...through hole 31...electron multiplier function plate 32...input 1lII electrode 33...output 1111 electrode

Claims (1)

[Scope of Claims] An insulating substrate, a cathode provided on the insulating substrate, a cathode tip formed on the cathode in the shape of a protrusion having a sharp tip, and an electrode hole surrounding the cathode tip. a gate electrode formed to have a transparent substrate facing the insulating substrate at a predetermined distance; an anode provided on a surface of the transparent substrate facing the cathode tip; In an image display device comprising a phosphor layer provided on the anode and emitting light in response to a radiant electron flow emitted from the cathode tip to the anode, an electron amplification function is provided between the gate electrode and the anode. 1. An image display device comprising: an electron multiplier plate that amplifies the emitted electron flow from the cathode tip by means of a through hole having an inner surface having a diameter of 1.