JPS5857854B2 - Hiyojisouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention controls electrons emitted from a planar electron source using electron flow control electrodes arranged in a manner that intersects with each other, and further accelerates this electron flow to collide with a phosphor. The present invention relates to a device that displays figures that emit light or television images.

As an example of a panel-type display device, a display device is known that includes a planar electron source in a vacuum container, grid-like control electrodes arranged in an intersecting manner, and a light-emitting surface coated with a phosphor.

However, it has not been put into practical use to date.

The main reasons for this are: (1) It is difficult to manufacture a grid-like control electrode with a structure that can reliably control electron flow.

(2) The connection between the control circuit and the large number of grid-shaped control electrode terminals appearing vertically and horizontally becomes extremely complicated.

The present invention provides an industrially valuable display device that completely overcomes these difficulties.

The present invention will be explained below with reference to the drawings.

FIG. 1 shows a perspective view of a display device that is an embodiment of the present invention.

In the figure, reference numeral 1 denotes a transparent casing, for example a glass container, the interior of which is maintained at a high vacuum.

2 is a planar electron source, and a thermionic electron source, a field emission electron source, a photoelectron emission source, etc. are used.

3 are the first and second electron flow control electrodes (second grid electrode and third grid electrode) of the electron flow control grid plates 4, 4';6;
The first grid electrode is made of a metal plate with holes formed at positions corresponding to the intersection points of 6'.

the electron flow control grid plate 4.4' is made of a semiconductor substrate;
The first and second electron flow control electrodes 6, 6' buttons, an image signal processing circuit 5, and a drive circuit are provided within the substrate or on the surface of the substrate.

Reference numeral 8 denotes an accelerating electrode made of a transparent conductive film that is adhered to the inner surface of the housing 1', and a phosphor film 7 that emits light upon collision with an electron beam is adhered to its surface.

Each part will be explained in more detail.

The housing 1 may be cylindrical or rectangular, but it is desirable that at least one surface (face surface) be smooth.

A transparent accelerating electrode 8 for accelerating electrons, such as a tin oxide film (trade name Nesa Glass), an indium oxide film, etc., is fixed to the inner wall of the face surface.

A thin layer of phosphor material, such as zinc oxide, is applied thereon.

Zinc oxide phosphor is known as a phosphor that can emit light upon collision with a low-energy electron beam, but it is possible to use the phosphor used in ordinary cathode ray tubes as long as the high acceleration voltage is not a problem. Needless to say.

Further, when emitting light using a high-energy electron beam, a metal back electrode used in a normal cathode ray tube can be used instead of a transparent electrode.

It is well known that color display can be achieved by alternately arranging phosphors that emit red, green, and blue light in correspondence to the positions of the holes in the electron flow control electrode.

The planar electron source 2 includes a hot cathode formed on a substrate with excellent heat insulation properties, a pseudo-planar electron source in which a plurality of hot cathode rays each having a metal wire surface coated with an oxide cathode material are arranged in parallel, a field emission source, and a photoelectron source. Cold cathode electron sources such as emissive sources are used.

As a substrate material with excellent heat insulating properties, a substrate formed by solidifying fine wires of potassium titanate can be used.

The thermal conductivity coefficient of this board is 0.043Kcal/m-h・
"c", which is about half of the thermal conductivity coefficient of ceramic fiber, 0, IKcat/m·h-'c, and has an extremely low thermal conductivity.

Therefore, by fixing this substrate to the inner wall surface of the casing, the temperature of the hot cathode can be maintained at 700 to 800 DEG C. while the outer wall surface of the casing is kept at almost room temperature.

Another advantage is that only a small amount of power is consumed to heat the cathode.

The hole diameter of the first grid electrode 3 is selected to be slightly larger than the diameter of the through holes of the electron flow control grid plate.

By changing the applied voltage, the electron flow rate can be controlled, and therefore the brightness of the display surface can be controlled uniformly over the entire display surface.

It also serves to relatively reduce the local potential distribution of the cathode that occurs when a directly heated cathode is used as an electron source.

Note that, when the cathode itself has an acceleration mechanism as a planar electron source, as in the case of a field emission cathode, the first grid electrode is not particularly necessary.

FIG. 2 shows a schematic cross-sectional view of the display device and the basic connections of each electrode.

In the figure, the sealing portion 10 is a power source for an electron source.

Reference numeral 11 denotes a power source for applying a positive voltage to the planar electron source 2 to the first grid electrode 3.

Reference numeral 12 denotes a power source for applying a bias voltage to the first electron flow control electrode 6 and the second electron flow control electrode 6', and a power source for operating the image signal processing circuit.

The same potential or a negative voltage with respect to the planar electron source 2 is applied to the first and second electron flow control electrodes.

Reference numeral 13 denotes a power source for applying a high voltage for accelerating the electron flow controlled by the first and second electron flow control electrodes 6, 6'.

14 is an image signal processing circuit that cannot be integrated within the first and second electron flow control electrode substrates.

In the case of television signals, this includes a tuning circuit, a detection circuit, a video signal amplification circuit, a sync separation circuit, etc.

FIG. 3a shows an overall view of the electron flow control grid plate 4, and a sectional view thereof.

The grating plate 4 is made of a semiconductor substrate, for example, with a thickness of 150 to 20 mm.
It consists of a 0μ silicon substrate.

In the figure, 18 is an input terminal for image signals and power supply.

Reference numerals 5 and 5' denote a signal processing circuit and a drive circuit 1, which are formed on a part of the semiconductor substrate, respectively.

The drive circuit 5' and the group of electron flow control electrodes 6 are formed at the same time and are directly connected on the same substrate.

In the signal processing circuit 5, for example, as shown in FIG. 4, a sample and hold circuit, an A-D conversion circuit, a control signal generation circuit, a load signal generation circuit, and -scanning line image signals are recorded. Memory circuits etc. are integrated.

An electrode drive circuit for controlling the electron beam current is integrated in the drive circuit 5'.

As a memory circuit element, it is also possible to form a CCD element that can sequentially transfer and parallelly transfer the image signals of (1) scanning lines.

electron flow control grid plates 4 provided substantially perpendicular to each other;
A through hole 15.15 is provided at the intersection of the 4' button and the electrodes 6, 6'.
' are provided for each.

Electron flow control grid electrode 6 can be constructed in several ways.

Figure 5a shows the second part.

Figures 5 and 5C show cross sections taken along line A--A.

An insulating layer 16 is formed on the surface of the electron flow control grid plate 4 made of semiconductor.
will be established.

When using a silicon substrate, this insulating layer 16 is obtained by oxidizing the surface of the substrate, for example, by thermal oxidation.

The example shown in FIG. 5 is a case where no insulating layer is provided on the inner wall surface of the through hole 15, and the example shown in FIG. 5C is a case where an insulating layer is provided on the inner wall surface.

In the structure of b, when an electron flow control voltage is applied to the electrode 6,
Since a potential difference occurs between the electrode 6 and the grid plate 4, the potential within the through hole 15 does not match the potential of the electron flow control electrode 6, and the electron flow control effect of the control electrode is reduced.

On the other hand, in structure C, the drawbacks of case b are eliminated, or because the inner wall surface is an insulator, electrons adhere to it, disturbing the electric field inside the through hole.

However, in either case, these drawbacks can be eliminated by setting the relationship between the depth and diameter of the through holes 15, 15' formed in the notch 17 under specific conditions.

Next, the reason will be explained.

Let us consider the electron flow control ability of the first electron flow control electrode 6 shown in FIG.

For example, assume that a positive voltage is applied to the first grid electrode 3 and the electron current control electrode 6'.

When the first electron flow control electrode 6 and the substrate potential are held at zero potential, the potential inside the through hole is a smear of the positive potential applied to the first grid electrode 3 and the second electron flow control electrode 6'. ” gives a slightly positive potential.

The value of this positive potential varies depending on the diameter R of the through hole and the thickness T of the substrate.

The smaller T/R, the higher the potential inside the hole.

That is, the present invention solves this problem by setting T/R<1.

Now, when a positive potential is applied to the first electron flow control electrode 6, the potential inside the through hole becomes higher, but when T/R>1, the influence of the potential on the inner wall of the hole is strong, and the potential inside the hole is almost It does not change.

In addition, in the case of the electron flow control electrode structure shown in FIG.
Since the inner wall surface is an insulator, electrons adhere to the wall surface and become negatively charged, and the inside of the through hole becomes a negative potential, making it impossible for electrons to pass through.

Even if a positive potential is applied to the electron flow control electrode, the charge on the wall surface does not change.

In any of the above cases, by reducing T/R, that is, by setting T/R<1, the influence of the inner wall surface of the through hole can be reduced, and the ability to control the electron flow can be improved.

An ideal electrode structure is one in which a portion of the electrode penetrates into the inner wall surface of the through hole.

The formation of the insulating layer 16 and the formation of the electron flow control electrode 6 are as follows:
The image signal processing circuit and the drive circuit can be integrated around the electron flow control electrode group at the same time, and are of great industrial value since they can eliminate the major drawbacks of this type of display device.

Furthermore, FIG. 6 shows another electrode configuration.

A shows a part of the electrode 6 group, and b shows its cross section.

Reference numeral 16 indicates an insulating layer provided on the surface of the grid plate. 4 is an electron flow control grid plate made of a semiconductor substrate, which is a P-type semiconductor.

19 is an n-type layer formed by thermal diffusion technology and serves as an electron flow control grid.

Generally, the electron flow control grid is controlled by applying the same potential or a slightly negative potential to the cathode, and applying a positive potential only when allowing electron flow to pass through.

A p-n junction is formed between the grating plate 4 and the electrode 19, and the configuration is such that a reverse voltage is applied to this p-n junction only when passing electron flow. Similar to the electrode configuration shown, it can be operated substantially in the same manner as a control electrode formed on an insulating layer.

Moreover, the advantage of this electrode configuration is that it can be easily applied to the inner wall surface of the through hole.
Since a -n junction can be formed and the inner wall surface can also be used as an electrode, the electric field within the through hole is not disturbed and the electron flow control effect is extremely good.

Furthermore, since the inner wall opening of the through-hole can be used as a conductor, the number of through-holes per unit area can be increased, and a high-quality image with better resolution can be obtained.

Name, the insulating layer 16 has a p-n button at the end of the p-n junction.
This is also necessary to prevent deterioration of the bond.

Next, its operation will be explained.

Electrons emitted from the flat electron source 2 are extracted by the first grid electrode 3 to which a positive voltage is applied.

Some of the accelerated electrons reach the vicinity of the first electron flow control electrode 6 through the through holes provided in the first grid electrode 3.

Since the first electron flow control electrode 6 is applied with the same potential or a negative voltage with respect to the flat electron source 2, it cannot pass through the through hole provided in the second electron flow control electrode 6 and is repelled. It flows into the first grid electrode 8.

Now, when a positive voltage is applied to one of the first electron flow control electrode groups, electrons pass through all the through holes provided in this electrode and reach the vicinity of the second electron flow control electrode 6'.

Similarly, when a positive voltage is applied to some of the second group of electrodes, the electrons pass through the through holes provided in the electrodes to which the voltage is applied.

The electron flow controlled in this manner is accelerated by the accelerating electrode 8 and collides with the phosphor film 7 to cause it to emit light.

For example, when used as a television image display device, the first
A vertical synchronization signal is sequentially applied to the electron flow control electrode group from above,
A television image can be obtained by simultaneously applying one scanning line worth of video signals to each second electron flow control electrode.

As explained above, the present invention can reduce the disturbance of the electric field in the through holes in the electron flow control grid plate,
In addition, highly accurate through holes can be easily formed, thereby providing a display device with extremely high industrial value.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a perspective view of a display device which is an embodiment of the present invention, Fig. 2 is a schematic sectional view of the display device, and Fig. 3 a and b are electron flow control grid plates, respectively. FIG. 4 is a block diagram of the image display circuit, FIG. 5 a, b, and c are plan views of an example of the electron flow control electrode, and FIG. FIG. 2 is a plan view and a cross-sectional view of another example. 2... Planar electron source, 4, 4'... Electron flow control grid plate, 6.6'... Electron flow control electrode, 8... Acceleration electrode, 15... Through hole.

Claims (1)

[Claims] 1. A planar electron source, an electron flow control grid plate provided with a group of electron flow control electrodes arranged parallel to the planar electron source and crossing each other, and accelerating the electron flow passing through the electron flow control grid plate. and a phosphor that emits light by collision of the electron flow accelerated by the acceleration means, and the electron flow control grid plate has a thickness of T and has a plurality of through holes for passing the electron flow. A display device comprising an insulating plate and an electrode formed at least around each of the through holes, and having a relationship of T/'R<1, where R is the diameter of the through hole.