JPH01100843A - Electron beam generator - Google Patents

Abstract

PURPOSE:To simplify the construction of a device having a deflecting function by constituting an equipment out of a surface transmitting type emission element having an electron generation source between electrodes and an electrode for drawing out electron beams from this generation source so as to change the voltage to be applied to the electrode to make the orbit of electron beams. CONSTITUTION:The surface of a glass board 1 is coated with a film 2 consisting of metal or metal oxide and at this central part an electron emitting part 5 is provided and electrons 3, 4 are provided apart on both sides of it to form a surface transmitting type emission element. Next, insulators 6 having the thickness are provided on the electrodes 3, 4, and thereon a plate-shaped electrode 7 consisting of metal mesh for drawing out electrons is bridged and an electric circuit 16 is connected to electrodes 3, 4, 7 and by changing voltage to be applied to these electrodes, electronic beams emitted from the emitting part 5 is let pass through the mesh of the electrode 7 toward the target arranged apart on the electrode 7. For this reason, the circuit is provided with a microprocessor 8 actuated by starting command, a memory, a D/A converter 15, a power source 13 and transistor groups 9-12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an electron beam generating device that uses a surface conduction type emitter as an electron beam generating source.

[Conventional technology]

Conventionally, so-called hot cathodes have been widely used as electron beam sources. However, in recent years, in the field of display devices and electron beam lithography devices, it has become possible to extract large currents with higher efficiency.
Moreover, there is a demand for an electron beam source that can be arranged in large numbers at a fine pitch.

In order to meet such demands, various cold cathode elements are being studied, and for example, methods have been reported in which field emission electron guns are formed by a thin film process and a large number of them are arranged two-dimensionally. (C, A, 5pindt et al.

J, Appl, Phys,, VOl, 47. N1
1.12. P5248° In order for such an electron beam generating device using a cold cathode to be widely applied, it is desirable that the generated electron beam can be deflected over a wide angle. For this purpose, it has conventionally been common practice to provide a pair of deflection electrodes on the cold cathode element for generating a deflection electric field.

Fig. 5 shows a cross section of an electron beam generator in which a pair of deflection electrodes are provided on a field emission type cold cathode. In the figure, 51 is a substrate, 52 is a metal thin film, and 53 is an electron radiation source. metal protrusion,
54 is an insulator, 55 is an extraction electrode, 56 and 57 are deflection electrodes provided facing each other, and 58 and 59 are members that serve as supports for the deflection electrodes 56 and 57 and also serve as electrical connections with the outside. It is.

When a voltage with 55 being positive is applied between the metal thin film 52 and the extraction electrode 55, at a voltage above a certain threshold,
An electron beam is emitted from the tip of the metal protrusion 53 by field emission. The electron beam is deflected by a voltage applied between deflection electrodes 56 and 57. In FIG. 5, a positive potential is applied to the electrode 56 and a negative potential is applied to the electrode 57, and the electron beam (dotted line)
A case is illustrated in which it is deflected in the X-axis stopping direction.

[Problem that the invention is trying to solve] However,
In the above-mentioned conventional example, the cold cathode element itself is manufactured by a thin film process, and therefore miniaturization is possible, but it is difficult to accurately attach deflection electrodes to the cold cathode element.

That is, in order to provide the deflection electrode with sufficient deflection sensitivity, it is advantageous to have a longer length along the electron flight direction (y direction). In order to make (in FIG. 5) sufficiently thick, it is difficult to manufacture the deflection electrode using a thin film process, and when a method such as thick film printing is used, the metal protrusion 53 Problems arise in that the metal members may be damaged or their surfaces may be contaminated.Therefore, metal members shown in FIG. The common method was to position it and then fix it.

However, as the cold cathode elements become finer or a larger number of elements are arranged, it becomes more difficult to manufacture and fix the deflection electrodes, and the manufacturing yield tends to drop significantly. Similarly, even in electron beam generators using cold cathodes other than field emission type, problems with deflection electrodes always occur when miniaturization or multiplication is performed.

The present invention has been made in view of the problems of the prior art described above.
The purpose is to realize an electron beam generating device that can deflect an electron beam with a simple electrode structure, is suitable for miniaturization and multiplication, and is easy to manufacture.

[Means for solving the problem (and operation)] According to the present invention, a surface conduction type emitter is used as an electron beam generation source, and a method for extracting the electron beam generated from the electron beam generation source of the element is used. The electrode has means for varying the trajectory of the emitted electron beam, thereby realizing an electron beam generating device with a simple structure that solves the above-mentioned problems.

Furthermore, the present invention provides an effect unique to the above device configuration in which the flight direction of the electron beam is controlled by the voltage applied between the two electrodes of the surface conduction type emission element and the voltage applied to the extraction electrode. We are using.

Before explaining the operation of the present device, the experiment that led the inventors to devise the present invention will be explained. The inventors measured the characteristics of a surface conduction type emission device using an experimental system as shown in FIG. We discovered that the trajectory of the electron beam changes when we change . For example, when observing the generation position using glass with a transparent electrode coated with a phosphor as the collector electrode 21, the light emitting point moves in the direction in which ΔXi decreases as Va increases.

In addition, as shown in FIG. 5(b), when the direction of the voltage Vf applied between the two poles of the surface conduction type emission element is reversed, the position of the light emitting point becomes opposite to the electron emitting part 5, and V
When Va is increased while f is constant, ΔX2 moves in the direction of decrease.

In this way, the electron beam trajectory becomes thicker due to the voltage applied to the electrodes provided parallel to the substrate surface of the electron-emitting device. This is not seen with radial cold cathodes.

Although the principle of this phenomenon has not been fully elucidated, the inventors are currently considering two causes as described below.

First, the potential distribution in the space above the surface conduction type element is, for example, in the form shown in Figure (c), and while the emitted electrons are flying in space, they are It is also possible that the effect is accelerated. The reason why the lines representing equipotentials in the figure are concentrated in the emission part 5 of the surface conduction type emission element is that this part of the thin film 2 has a particularly high resistance due to the forming process, and the resistance between the electrodes 3 and 4 is increased by the forming process. This is because it is considered that most of the voltage Vf applied to is applied here. When a large voltage is applied by the collector electrode 21, the potential distribution becomes as shown in the figure (d), but as is clear from the figure, the direction of the force applied to the electrons is more in the X direction. It's getting closer. Therefore, the larger the voltage Va applied to the collector electrode 21, the thicker the X-direction component (becomes) compared to the X-direction component of the acceleration that electrons receive, and as a result, as described in FIG. It moves in the direction in which Δx1 becomes smaller.

Second, it is considered that an electron beam having an initial velocity in the X direction is emitted from the surface conduction type emitter. The mechanism by which electron emission from surface conduction type emitters occurs is not fully understood at present, but the local region 5 of the thin film 2 is exposed to an applied voltage Vf.
Therefore, a strong electric field parallel to the X-axis should be generated, and it is quite conceivable that the electrons flying into space have a velocity component in the X direction. Therefore, as shown in FIG. 2(e), the initial velocity υ from the surface conduction type emitter. =(
Assume that electrons with υOx, υoy) are emitted.

It is assumed that these electrons are accelerated in the X direction by the collector electrode potential Va [v]. (Actually, as explained in the first effect above, electrons are thought to be accelerated in the X direction due to the distortion of the equipotential surface during flight, but in order to simplify the model, here Assume that the potential of the surface of the type-emitting element is 0 [V], and that all equipotential surfaces in the space above the element are parallel to the element surface.) If the electron-emitting part is the coordinate origin and t is time (S), then
Coordinates of electrons emitted at t=O(S) (x + y)
is, y= υ 0.・t ten-at”
・・・・・・・・・・・・・・・・・・・・・ ■
X= υOx 'j
Pa・・・・・・・・・・・・・・・ ■It is expressed as. Here, a [m/S2] is the acceleration that the electron receives.

By eliminating t from ■ and ■ and substituting a found in ■, the orbit of the electron can be found and expressed as follows.

■As is clear from the equation, the trajectory of the electron beam changes depending on the voltage Va applied to the collector electrode, and as Va increases,
The slope of the parabola increases, and ΔX moves in the direction of decreasing.

As explained above, the inventors discovered that the first effect, that is, the potential distribution in the space above the element is distorted, and this is caused by Va.
The phenomenon explained earlier occurs due to two effects: the initial velocity of the emitted electron has an X-direction component, and therefore the trajectory changes due to Va. I believe.

EMBODIMENT OF THE INVENTION The electron beam generator of this invention is demonstrated in detail based on an Example below.

[Embodiment 1] FIG. 1 is a cross-sectional view of the first embodiment of the present invention, where l is a glass substrate, 2 is a thin film made of, for example, a metal or metal oxide, and 3 and 4 are the thin films 2. (In the present invention, depending on the material of 2, an electrode formed of the same material as electrodes 3 and 4 may be used.) 5 is a surface conduction type emission. In the field of devices, the electron emitting portion is formed by subjecting the thin film 3 to a conventionally known process called forming, and the above-mentioned elements 1 to 5 constitute a surface conduction type emission device. Further, 6 is an insulating layer, and 7 is an electrode for extracting electrons emitted from the electron emitting portion. In this example, a plate-shaped electrode is used using a metal mesh having many fine holes.

In addition, in the figure, the part surrounded by dotted line 16 is an electric circuit for driving this device, 8 is a control microprocessor, 9
, 10, 11.12 are switching transistors, 13
1 is a constant voltage source that generates a constant voltage, 14 is a memory, and 15 is a D/A converter.

First, the direction in which the electron beam should be emitted to the present device (ie, the direction of the target) is given as a drive command from the outside.

Based on the instructions, the microprocessor 8 appropriately controls the voltages applied to the electrodes 3.4 of the surface conduction type emitter and the plate electrode 7, and causes the electron beam to fly toward the target.

The operation of each part will be explained step by step below. First, the voltage applied to the surface conduction type emission device is controlled as follows. The microprocessor 8 controls the O of transistors 9 to 12.
Signals Sl to S4 are output for controlling N and OFF, and this combination allows the electrode 3 of the surface conduction type emitter to
．． The polarity of the voltage applied to 4 is determined. In the example shown in FIG. 1, since the target is located closer to the electrode 4 than the electron emitting section 5, Vf should be applied in the direction shown in FIG. 2(b). , microprocessor 8
turns on transistors 9 and 12 and turns off transistors 10 and 11
Control signals 81 to S4 are generated to cause F. (Also, if the target is located closer to the electrode 3 than the electron emitting part 5, the microprocessor 8 controls the transistor lO so that Vf is applied in the direction shown in FIG. and 11@ON, and a control signal 5l-84 is generated to turn 9 and 12 OFF.) On the other hand, the voltage applied to the plate electrode (metal mesh) 7 is controlled as follows. First, the microprocessor 8 calculates how far ΔX in FIG. 1 should be in order to make the electron beam fly toward the target, and outputs it to the memory 14.

The memory 14 stores the voltage applied to the electrode 7 in advance,
Since the relationship of the displacement amount ΔX is stored, when the calculation result is input from the microprocessor 8, the voltage to be applied is immediately outputted to the D/A converter 15 as digital numerical data. The D/A converter 15 generates a voltage based on the numerical data and applies it to the electrode 7.

Through the series of operations described above, this device is capable of deflecting an electron beam over a wide range.

[Example 2] FIG. 3 shows two other embodiments of the present invention.

In the first embodiment, a metal mesh was used as the plate electrode, which is a main component of the present invention, but instead, for example, a metal plate 31 shown in FIG. b
It is also possible to use a metal plate 33 shown in ). 31 is
It is suitable for selectively irradiating a plurality of targets arranged at certain intervals, and 33 is suitable for continuously irradiating electron beams. 31 or 3
A metal plate like No. 3 can be manufactured inexpensively and with high precision by photo-etching.

Further, it is desired that the spacer separating the metal plate and the surface conduction type emission element has good electrical insulation properties and good dimensional accuracy of the shape, but the member 32 shown in FIG. It can be easily manufactured using synthetic glass. When photosensitive glass is used, it is possible to manufacture more complex shapes, so in some cases, the substrate 1 or the metal plate 31 may be
A groove for positioning may be provided in the contact portion with.

In the case of FIG. 3B, an insulating layer 34 is formed on the lower surface of the metal plate 33 by thick film printing to serve as a spacer. As mentioned in the prior art section, for example, it is difficult to laminate an insulating layer or deflection electrode pair on top of a field emission type electron gun by thick film printing, but in the case of the present invention, as an electrode Since the method uses a metal plate and an insulating layer is printed on the metal plate side, problems such as element damage and contamination do not occur.

In this way, in the case of the present invention, the electrode structure for realizing the deflection function is simple and can be manufactured using photoetching technology or printing technology.
A multi-electron beam source in which a large number of the devices shown in 2 are arranged on the same substrate can be easily realized.

[Example 3] Also, based on the basic idea of the present invention, the target to be irradiated with the electron beam deflected may be adjacent to the plate-shaped electrode, or may be the plate-shaped electrode itself. . Therefore, it goes without saying that a display device as shown in FIG. 4 is also included in the concept of the present invention. In the figure, 41 is a glass plate, 42 is a transparent electrode provided on the lower surface of the glass plate 41, and 43 to 46 are phosphors.

This device controls the polarity of the voltage applied between the electrodes 3 and 4 and the magnitude of the voltage applied to the transparent electrode 42, as can be inferred from the explanation of FIGS. 2(a) and 2(b) above. By doing so, one of the phosphors 43 to 46 is caused to selectively emit light for display.

At that time, considering that when the electron beam irradiates the phosphor 44 or 45, it is accelerated by a higher voltage than when irradiating the phosphor 43 or 46, (a) 44.45:
A phosphor material that is more suitable for high-speed electron beams than 43.46 is used.

Alternatively, (b) The coating thickness of the phosphor of 44.45 is made larger than that of 43.46.

You may try to do something like this.

The inventors have succeeded in fabricating a high-luminance, thin display device by arranging a plurality of display units two-dimensionally as shown in FIG. 4.

〔Effect of the invention〕

As explained above, in the present invention, by utilizing the phenomenon peculiar to surface conduction type emission elements, an electron beam generating device having a deflection function can be realized with an extremely simple structure. As a result, it has become possible to easily miniaturize and multiply devices, and the cost required for manufacturing has also become low.

[Brief explanation of the drawing]

Figure 1: A diagram showing the main configuration of an electron beam generator in which the present invention was implemented. Figure 2: A diagram explaining the experiment that led to the invention. Figure 3: Another embodiment of the present invention. FIG. 4: A diagram showing a display device according to another embodiment of the present invention; FIG. 5: A diagram showing an example of a conventional electron beam generating device; l is a substrate; 3.4 is the electrode of the surface conduction type emission device; 5 is the electron emission region; 6, 32°34
is an insulating spacer, and 7, 31, and 33 are plate electrodes. Muzuto's Regret 4 No. 51

Claims (9)

[Claims] (1) An electron beam generating device having a surface conduction type emitter having an electron beam generating source between electrodes, and an electrode for extracting the electron beam generated from the electron beam generating source, the electron beam generating device extracting the electron beam. An electron beam generating device characterized in that the electrode for the electron beam has means for varying the trajectory of the emitted electron beam. (2) The electron beam generating device according to claim 1, wherein the means for varying the trajectory of the emitted electron beam is to change a voltage applied to an electrode for extracting the electron beam. (3) By increasing the voltage applied to the electrode for extracting the electron beam, the deviation of the trajectory of the emitted electron beam with respect to the normal line of the electron emitting section is reduced. The electron beam generator according to item 2. (4) By changing the voltage applied to the electrode for extracting the electron beam and the voltage applied between the electrodes,
The electron beam generating device according to claim 1, characterized in that the trajectory of the emitted electron beam is varied. (5) The trajectory of the emitted electron beam is reversed with respect to the normal line of the electron emitting part by changing the polarity of the voltage applied between the electrodes. Electron beam generator. (6) The electron beam generating device according to claim 1, wherein the electrode for extracting the electron beam is an electrode held above the surface conduction type emission element and substantially parallel to the element. (7) The electron beam generating device according to claim 6, wherein the electrode for extracting the electron beam is a plate-shaped electrode made of a metal mesh having a plurality of holes. (8) In the electron beam generating device, the voltage applied between the electrodes or the voltage applied to the electrode for extracting the electron beam is controlled by a microprocessor. electron beam generator. (9) The electron beam generator according to claim 1, wherein the electron beam generator includes a memory device and a D/A converter.