JP2003045352A - Electron gun for cathode ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron gun for a cathode ray tube enabled to instantaneously operate, consume small power, and easy to manufacture. SOLUTION: As shown in the figure (a), the electron gun for a cathode ray tube is composed of a cold cathode electrode 10 composed of a field emission type electron source, and an electrostatic lens 20 as a convergence electrode converging the electrons emitted from the cold cathode electrode 10. The electrostatic lens 20 is composed of a third grid G3, a fourth grid G4, and a fifth grid G5. For the cold cathode electrode 10, as shown in the figure (b), a strong electric field drift layer 6 composed of an oxidized porous polycrystalline silicon layer is formed on the main surface side of an n-type silicon substrate 1, and a surface electrode 7 is formed on the strong electric field drift layer 6. An ohmic electrode 2 is formed on the back surface of the n-type silicon substrate 1, and a lower electrode is formed by the n-type silicon substrate 1 and the ohmic electrode 2.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electron gun for a cathode ray tube.

[0002]

2. Description of the Related Art As shown in FIG. 8, a conventional electron gun for a cathode ray tube has a hot cathode 30, a cathode sleeve 31, and a first cathode.
Grid G1, second grid G2, third grid G3,
The fourth grid G4 and the fifth grid G5 are provided, and the beam current amount is controlled by the cathode sleeve 31, the first grid G1, and the second grid G2, and the third grid G4.
The third, fourth grid G4, and fifth grid G5 constitute a focusing electrode (electrostatic lens) to accelerate and focus the electron beam.

As a cathode used in this type of electron gun, there are a hot cathode disclosed in JP-A-11-224619 and a Spindt-type cold cathode disclosed in JP-A-9-82248.

The above-mentioned hot cathode has a feature that the electron emission is stable and robust, but in order to emit the electron, 7
Since it needs to be heated to a high temperature of 00 ° C. or higher, standby power is required, and there are problems in terms of startability and power consumption.

On the other hand, since the Spindt-type cold cathode does not need to be heated, it has the characteristics that it can be operated immediately and the power consumption can be reduced as compared with the hot cathode. Here, the Spindt-type cold cathode has a basic configuration as shown in FIG.
That is, the Spindt-type cold cathode includes a conical emitter tip 41 and a gate electrode 42 that has a radiation hole 42a that exposes the tip of the emitter tip 41 and that is arranged insulated from the emitter tip 41. By applying a high voltage to the gate electrode 42 with the emitter tip 41 as a cathode in a vacuum, an electron beam is emitted from the tip of the emitter tip 41 through the emission hole 42a.

However, since the electron emission angle (divergence angle) emitted from the tip of the emitter tip 41 is relatively large in the Spindt-type cold cathode, a focusing gate electrode is provided on the above-mentioned gate electrode 42 via an insulating layer. Although a so-called two-stage gate structure Spindt-type cold cathode has been proposed, it has a drawback that the structure is complicated and manufacturing is difficult.

As an electron gun using the Spindt-type cold cathode having the one-stage gate structure, an electron gun having the Spindt-type electrode 100 having the configuration shown in FIG. 10 and having the configuration shown in FIG. 11 has been proposed.

Spindt-type cold cathode 10 having the structure shown in FIG.
In the case of 0, the insulating layer 43 and the conical emitter tip 41 are formed on the cathode electrode layer 102 made of a conductive material and formed on one surface of the n-type silicon substrate 101.
Radiation hole 4 that exposes the tip of the emitter tip 41 above
The gate electrode 42 having 2a is formed, and the beam current amount can be controlled by changing the magnitude of the voltage applied between the n-type silicon substrate 101 and the gate electrode 42. In the Spindt-type cold cathode 100 having the configuration shown in FIG. 10, in order to reduce the electrostatic capacitance between the gate electrode 42 and the n-type silicon substrate 101, silicon oxide is formed on the one surface side of the n-type silicon substrate 101. The insulating layer 103 made of a film is formed so as to be embedded. Here, the insulating layer 103 is formed by making a part of the n-type silicon substrate 101 porous by anodic oxidation treatment, then thermally oxidizing it, and further planarizing it by chemical mechanical polishing (CMP).

In the electron gun shown in FIG. 11, an auxiliary focusing electrode 45 arranged in close contact with the gate electrode 42 on the one surface side of the Spindt-type cold cathode 100 and an anode 46 arranged opposite to the focusing electrode 45. Equipped with a Spindt-type cold cathode 10
When a gate voltage is applied to the zero gate electrode 42 through the auxiliary focusing electrode 45, electrons are emitted from the tip of the emitter tip 41 and pass through a hole 46a penetrating the anode 46. In the configuration of FIG. 11, the anode 46 corresponds to the first grid G1 in FIG. 8, and the second grid G2, the third grid G3, the fourth grid G4, and the fourth grid G4 are used for use as an electron gun for a cathode ray tube. 5
It is necessary to separately provide the grid G5.

[0010]

However, as shown in FIG.
Since the Spindt-type electrode 100 is used as the cold cathode in the electron gun having the configuration shown in FIG.
There is a problem in that it is difficult to control the beam current amount because it is affected by the electric field due to the grid G1, the second grid G2, etc. Further, since the cold cathode as the electron source is composed of the Spindt-type cold cathode 100, there is a problem that the structure of the cold cathode is complicated and the manufacture is difficult.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electron gun for a cathode ray tube, which can be operated immediately and have low power consumption and which is easy to manufacture.

[0012]

In order to achieve the above-mentioned object, the invention of claim 1 is a strong semiconductor layer comprising a porous semiconductor layer oxidized or nitrided or oxynitrided between a lower electrode and a surface electrode facing each other. A cold cathode in which electrons injected from the lower electrode into the strong electric field drift layer via the electric field drift layer drift toward the surface electrode and are emitted through the surface electrode, and a focusing electrode for focusing the electron beam emitted from the cold cathode. By adopting a cold cathode as an electron source, immediate operation and low power consumption are possible, and moreover, between the lower electrode and the surface electrode facing each other. Electrons emitted from a cold cathode having a strong electric field drift layer consisting of an oxidized, nitrided, or oxynitrided porous semiconductor layer are emitted along the direction normal to the surface electrode. Since the electron emission angle is smaller than that of the Spindt-type cold cathode, it is not necessary to provide the first grid and the second grid as in the conventional case, the structure is simple and the manufacturing is easy, and the beam current amount can be controlled. It will be easier.

According to the invention of claim 2, in the invention of claim 1, since the beam current amount is controlled by controlling the potential of the lower electrode of the cold cathode, the beam current amount can be controlled only by the potential of the lower electrode, The beam current amount can be controlled with good controllability because it is not affected by the electric field due to the anode as in the conventional case.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) As shown in FIG. 1A, an electron gun for a cathode ray tube according to this embodiment has a cold cathode 10 composed of a field emission type electron source and a cold cathode 10. The electrostatic lens 20 is a focusing electrode that focuses the generated electrons. Here, the electrostatic lens 20 is shown in FIG.
The third grid G3, the fourth grid G4, and the fifth grid G5 described in the conventional configuration shown in FIG.

The cold cathode 10 is, as shown in FIG.
N-type silicon substrate as a conductive substrate ((100) substrate of single crystal silicon whose resistivity is relatively close to that of the conductor)
The strong electric field drift layer 6 made of an oxidized porous polycrystalline silicon layer is formed on the main surface side of
The surface electrode 7 is formed on top. An ohmic electrode 2 is formed on the back surface of the n-type silicon substrate 1.
Here, a material having a small work function (for example, gold) is used for the surface electrode 7, and the film thickness of the surface electrode 7 is 10 to 10.
It is set to about 15 nm. Further, in this embodiment, the n-type silicon substrate 1 and the ohmic electrode 2 form a lower electrode. Therefore, the surface electrode 7 faces the lower electrode, and the strong electric field drift layer 6 is interposed between the lower electrode and the surface electrode 7. Note that in the example shown in FIG. 1B, the strong electric field drift layer 6 is formed on the main surface of the n-type silicon substrate 1, but between the n-type silicon substrate 1 and the strong electric field drift layer 6, for example, A semiconductor layer made of a non-doped polycrystalline silicon layer may be interposed.

Hereinafter, a method of manufacturing the cold cathode 10 will be described with reference to FIG.
Will be described with reference to.

First, an ohmic electrode 2 is formed on the back surface of the n-type silicon substrate 1, and then a non-doped polycrystalline silicon layer 3 is formed as a semiconductor layer on the main surface of the n-type silicon substrate 1, so that the structure shown in FIG. A structure as shown in a) is obtained. As a method of forming the polycrystalline silicon layer 3, for example, a CVD method (eg, LPCVD method, plasma CVD method, catalytic CVD method, etc.), sputtering method, or CGS is used.
(Continuous Grain Silicon) method or the like may be adopted.

After the non-doped polycrystalline silicon layer 3 is formed, the polycrystalline silicon layer 3 is made porous in the anodic oxidation process to form a porous polycrystalline silicon layer 4 which is a porous semiconductor layer. A structure as shown in FIG. 2B is obtained. Here, in the anodizing process, 5
Approximately 1: 1 of 5 wt% hydrogen fluoride aqueous solution and ethanol
Using a anodic oxidation treatment tank containing an electrolytic solution composed of the mixed solution mixed in step 1, the platinum electrode (not shown) is used as the negative electrode and the n-type silicon substrate 1 (ohmic electrode 2) is used as the positive electrode to form the polycrystalline silicon layer 3 Porous polycrystalline silicon layer 4 is formed by anodizing at a constant current while irradiating light. Although the polycrystalline silicon layer 3 is made entirely porous in the present embodiment, a part thereof may be made porous.

After completion of the above-mentioned anodizing process,
By oxidizing the porous polycrystalline silicon layer 4 in the oxidation step, the strong electric field drift layer 6 made of the oxidized porous polycrystalline silicon layer is formed, and the structure as shown in FIG. 2C is obtained. Although the rapid heating method (rapid thermal oxidation: RTO) is adopted in the oxidation step in the present embodiment, an electrolyte solution (for example, diluted sulfuric acid, diluted nitric acid, aqua regia, etc.) is used.
Using a oxidization treatment tank containing a platinum electrode (not shown) as a negative electrode and the n-type silicon substrate 1 (ohmic electrode 2) as a positive electrode, a constant current is passed to electrochemically form the porous polycrystalline silicon layer 4. You may employ the method of oxidizing etc.

After the strong electric field drift layer 6 is formed, a surface electrode 7 made of a gold thin film is formed on the strong electric field drift layer 6 to form a field emission type electron source having a structure shown in FIG. 2D. The cold cathode 10 is obtained. In the present embodiment, the surface electrode 7 is formed by the electron beam evaporation method, but the method of forming the surface electrode 7 is not limited to the electron beam evaporation method, and for example, the sputtering method may be used.

Next, the basic operation of the cold cathode 10 is shown in FIG.
Also, description will be made with reference to FIG.

In order to emit electrons from the cold cathode 10 described above, as shown in FIG. 3, a collector electrode 21 opposed to the surface electrode 7 is provided, and the surface electrode 7 and the collector electrode 21 are provided.
In the state where a vacuum is applied between the surface electrode 7 and the lower electrode, a DC voltage Vps is applied between the surface electrode 7 and the lower electrode so that the surface electrode 7 is on the higher potential side (positive electrode) with respect to the lower electrode. A direct-current voltage Vc is applied between the collector electrode 21 and the surface electrode 7 so that is on the high potential side with respect to the surface electrode 7. If each DC voltage Vps, Vc is set appropriately, n
The electrons injected from the silicon substrate 1 drift in the strong electric field drift layer 6 and are emitted through the surface electrode 7 (note that the alternate long and short dash line in FIG. 3 indicates the flow of electrons e ⁻ emitted through the surface electrode 7). .

By the way, as described in the above-mentioned manufacturing method, the strong electric field drift layer 6 is formed by making the non-doped polycrystalline silicon layer porous by anodic oxidation and then oxidizing it by a rapid heating method. Although formed, the surface of the grains contained in the polycrystalline silicon layer before the anodic oxidation treatment was made porous by the anodization treatment, and the crystal state of the remaining grains was maintained, so that FIG. As shown in FIG.
A thin silicon oxide film 52 formed on the surface of each grain 51, a large number of nanometer-sized (for example, about 10 nm) microcrystalline silicon (semiconductor microcrystals) 63 interposed between the grains 51, and each microcrystalline silicon 63. It is considered that at least the silicon oxide film (insulating film) 64 formed on each surface and having a film thickness smaller than the crystal grain size of the microcrystalline silicon 63 is included.

In the cold cathode 10 described above, it is considered that electron emission occurs in the following model. When the DC voltage applied as a positive electrode to the lower electrode composed of the n-type silicon substrate 1 and the ohmic electrode 2 reaches a predetermined value (critical value), the surface field electrode 7 moves from the n-type silicon substrate 1 side to the strong electric field drift layer. Electrons are injected into 6 by thermal excitation. on the other hand,
A large number of microcrystalline silicon 63 having a crystal grain size of nanometer is present in the strong electric field drift layer 6.
Since the silicon oxide film 64, which is an insulating film having a thickness smaller than the crystal grain size of the microcrystalline silicon 63, is formed on the surface of the microcrystalline silicon 63, the electric field applied to the strong electric field drift layer 6 is almost the microcrystalline silicon 63. Since it is applied to the silicon oxide film 64 formed on the surface of, the injected electrons are accelerated by the strong electric field applied to the silicon oxide film 64 and drift in the strong electric field drift layer 6 toward the surface electrode 7 (note that The upward arrow in FIG. 4 indicates the drift direction of the electron e ⁻ ). Here, the crystal grain size of the microcrystalline silicon 63 is the mean free path of electrons (the mean free path of electrons in silicon is 5
It is sufficiently smaller than 0 nm),
The electrons reach the surface of the strong electric field drift layer 6 with almost no collision with the microcrystalline silicon 63. In short, the electrons injected into the strong electric field drift layer 6 are accelerated by the electric field applied to the silicon oxide film 64 on the surface of the microcrystalline silicon 63 without scattering due to collision, and the electrons of the next microcrystalline silicon 63 Energy is increased by repeating the phenomenon of plunging into the silicon oxide film 64 on the surface. Therefore, the electrons that have reached the surface of the strong electric field drift layer 6 are hot electrons, and since the hot electrons have energy of several kT or more than in the thermal equilibrium state, they easily tunnel through the surface electrode 7 and are emitted into a vacuum. .

In the cold cathode 10 having the above structure, the current flowing between the surface electrode 7 and the lower electrode (ohmic electrode 2) is called a diode current Ips, and the current flowing between the collector electrode 21 and the surface electrode 7 is called. Is referred to as an emission current (emitted electron current) Ie (see FIG. 3), the electron emission efficiency increases as the ratio of the emission current Ie to the diode current Ips (= Ie / Ips) increases. In the cold cathode 10 described above, the DC voltage Vps is 10
Since electrons can be emitted even at a low voltage of about 20 V, low power consumption can be achieved. Further, in the above-mentioned cold cathode 10, the electron emission characteristics (emission current Ie, electron emission efficiency, etc.) have a low degree of vacuum dependency, and the popping phenomenon does not occur during electron emission, and electrons are stably emitted with high electron emission efficiency. can do. Here, the popping phenomenon does not occur because the heat generated in the strong electric field drift layer 6 during the operation of the cold cathode 10 is dissipated through the grains 51 in the strong electric field drift layer 6 and the temperature of the strong electric field drift layer 6 rises. It is thought that this is because it is suppressed.

Further, the cold cathode 10 described above has a high vacuum (10
^-5 Pa to 10 ^-6 Pa) can be used in a lower vacuum (10 ^-4 to 10 ¹ Pa) as compared with the Spindt-type cold cathode that needs to be used at ^-5 Pa to 10 ^-6 Pa). It will be easier.

In the cathode ray tube electron gun of this embodiment, however, the emission direction of the electron beam emitted through the surface electrode 7 of the cold cathode 10 is easily aligned with the normal direction of the surface electrode 7.
Since electrons are emitted along the normal direction of the surface electrode 7,
The electron emission angle is smaller than that of the Spindt-type cold cathode, and there is no need to provide the first grid G1 and the second grid G2 as in the conventional configuration shown in FIG. Moreover, the control of the beam current amount becomes easy.
Further, in the electron gun for the cathode ray tube of the present embodiment, since the cold cathode 10 is adopted as the electron source, immediate operation and low power consumption are possible.

In the cathode ray tube electron gun of the present embodiment, if the potential of the lower electrode of the cold cathode 10 is V1 and the potential of the surface electrode 7 is V2 (see FIG. 1A), the lower portion of the cold cathode 10 will be used. Since the beam current amount is controlled by controlling the electrode potential V1, the beam current amount can be controlled only by the lower electrode potential V1 and is not affected by the electric field from the anode as in the conventional case. Can be controlled with good controllability.

(Embodiment 2) The basic structure of the electron gun for cathode ray tubes of this embodiment is substantially the same as that of Embodiment 1, and one of the insulating substrates made of a glass substrate (eg, quartz glass substrate) is used as a conductive substrate. A difference is that a conductive film made of a metal film (for example, a tungsten film) is provided on the surface.

As shown in FIG. 5, the cold cathode 10 in this embodiment has a strong electric field drift layer 6 made of an oxidized porous polycrystalline silicon layer formed on a conductive layer 12 on an insulating substrate 11, A surface electrode 7 is formed on the strong electric field drift layer 6. In this embodiment, the conductive layer 12 constitutes the lower electrode. Therefore, also in the cold cathode 10 in this embodiment, the surface electrode 7 faces the lower electrode, and the strong electric field drift layer 6 is interposed between the lower electrode and the surface electrode 7. The structure of the surface electrode 7 is the same as that of the first embodiment.

Hereinafter, a method of manufacturing the cold cathode 10 according to this embodiment will be described with reference to FIG.

First, a conductive layer 12 made of a metal film (for example, a tungsten film) is formed on one surface side of the insulating substrate 11 by a sputtering method or the like to form a conductive substrate, and then the main surface of the conductive substrate is formed. Side (here, the conductive layer 12
The upper layer is a non-doped polycrystalline silicon layer 3 as a semiconductor layer.
By forming the, the structure as shown in FIG. 6A is obtained. As a method of forming the polycrystalline silicon layer 3, for example, a CVD method (LPCVD method, plasma CVD method)
Method, catalytic CVD method, etc., sputtering method and CGS (Contin
The uous grain silicon) method or the like may be adopted.

After the non-doped polycrystalline silicon layer 3 is formed, the polycrystalline silicon layer 3 is made porous in the anodic oxidation process to form a porous polycrystalline silicon layer 4 as a porous semiconductor layer. A structure as shown in FIG. 6B is obtained. Here, in the anodizing process, 5
Approximately 1: 1 of 5 wt% hydrogen fluoride aqueous solution and ethanol
A platinum electrode (not shown) is used as a negative electrode and a conductive layer 1 is used by using an anodizing treatment tank containing an electrolytic solution composed of the mixed solution mixed in.
The porous polycrystalline silicon layer 4 is formed by performing anodic oxidation at a constant current while irradiating the polycrystalline silicon layer 3 with light using 2 as a positive electrode. Although the polycrystalline silicon layer 3 is made entirely porous in the present embodiment, a part thereof may be made porous.

After completion of the above-mentioned anodizing process,
By oxidizing the porous polycrystalline silicon layer 4 in the oxidation step, the strong electric field drift layer 6 made of the oxidized porous polycrystalline silicon layer is formed, and the structure as shown in FIG. 6C is obtained. Although the rapid heating method (rapid thermal oxidation: RTO) is adopted in the oxidation step in the present embodiment, an electrolyte solution (for example, diluted sulfuric acid, diluted nitric acid, aqua regia, etc.) is used.
Using a oxidization treatment tank containing a platinum electrode (not shown) as a negative electrode and the n-type silicon substrate 1 (ohmic electrode 2) as a positive electrode, a constant current is passed to electrochemically form the porous polycrystalline silicon layer 4. You may employ the method of oxidizing etc. If an electrochemical oxidation method is adopted, a relatively inexpensive glass substrate having a low heat resistant temperature can be used as the insulating substrate 11.

After the strong electric field drift layer 6 is formed, a surface electrode 7 made of a gold thin film is formed on the strong electric field drift layer 6 to form a field emission electron source having a structure shown in FIG. 6D. The cold cathode 10 is obtained. In the present embodiment, the surface electrode 7 is formed by the electron beam evaporation method, but the method of forming the surface electrode 7 is not limited to the electron beam evaporation method, and for example, the sputtering method may be used.

Next, the basic operation of the cold cathode 10 is shown in FIG.
Will be described with reference to.

In order to emit electrons from the cold cathode 10 described above, as shown in FIG. 7, a collector electrode 21 opposed to the surface electrode 7 is provided, and the surface electrode 7 and the collector electrode 21 are provided.
The surface electrode 7 has the conductive layer 12 in a vacuum state between
A DC voltage Vps is applied between the surface electrode 7 and the conductive layer 12 so as to be on the high potential side (positive electrode) with respect to
A DC voltage Vc is applied between the collector electrode 21 and the surface electrode 7 so that the collector electrode 21 is on the high potential side with respect to the surface electrode 7. If the DC voltages Vps and Vc are appropriately set, the electrons injected from the conductive layer 12 drift in the strong electric field drift layer 6 and are emitted through the surface electrode 7 (note that the chain line in FIG. 7 indicates the surface electrode). 7 shows the flow of electrons e ⁻ emitted through 7).

In the cold cathode 10 of this embodiment, the current flowing between the surface electrode 7 and the conductive layer 12 is called a diode current Ips, and the current flowing between the collector electrode 21 and the surface electrode 7 is an emission current ( Emitted electron current) Ie
If it is called (see FIG. 7), the diode current Ips
Ratio of emission current Ie to (= Ie / Ips)
Is larger, the electron emission efficiency is higher.

As in the first embodiment, the strong electric field drift layer 6 has a large number of columnar polycrystalline silicon grains 51, and a thin silicon oxide film formed on the surface of each grain 51, as shown in FIG. 52, a large number of nanometer-sized (for example, about 10 nm) microcrystalline silicon (semiconductor microcrystals) 63 interposed between the grains 51, and crystal grains of the microcrystalline silicon 63 formed on the surface of each microcrystalline silicon 63. It is considered that at least the silicon oxide film (insulating film) 64 having a film thickness smaller than the diameter is included.

Therefore, the cold cathode 10 according to the present embodiment.
Then, it is considered that electron emission occurs in the following model. That is, a DC voltage Vps is applied between the surface electrode 7 and the conductive layer 12 with the surface electrode 7 as a positive electrode, and
The collector electrode 2 is provided between the collector electrode 21 and the surface electrode 7.
When the DC voltage Vps reaches a predetermined value (critical value) by applying the DC voltage Vc with 1 as a positive electrode, electrons e ⁻ are generated from the conductive layer 12 as the lower electrode to the strong electric field drift layer 6 by thermal excitation. Injected. On the other hand, most of the electric field applied to the strong electric field drift layer 6 is applied to the silicon oxide film 64, so the injected electrons e ⁻ are accelerated by the strong electric field applied to the silicon oxide film 64, and the strong electric field drift layer 6 4 drifts toward the surface in the direction of the arrow in FIG. 4 (upward in FIG. 4), tunnels through the surface electrode 7, and is discharged into a vacuum. Then,
In the strong electric field drift layer 6, electrons injected from the conductive layer 12 are accelerated by an electric field applied to the silicon oxide film 64 without being scattered by the microcrystalline silicon 63, drift, and are emitted through the surface electrode 7 ( (Ballistic electron emission phenomenon) and heat generated in the strong electric field drift layer 6 is radiated through the grains 51, so that popping phenomenon does not occur at the time of electron emission, and electrons can be emitted stably. The electrons that have reached the surface of the strong electric field drift layer 6 are considered to be hot electrons, and easily tunnel through the surface electrode 7 and are emitted into a vacuum.

Therefore, in the cathode ray tube electron gun of this embodiment, as in the first embodiment, the emission direction of the electron beam emitted through the surface electrode 7 of the cold cathode 10 is easily aligned with the normal direction of the surface electrode 7, Since electrons are emitted along the normal direction of the surface electrode 7, the electron emission angle is smaller than that of the Spindt-type cold cathode, and the first grid G1 and the second grid G2 are arranged as in the conventional configuration shown in FIG. Since it is not necessary to provide the structure, the structure is simplified and the manufacturing is facilitated, and the control of the beam current amount is facilitated. Further, in the electron gun for the cathode ray tube of the present embodiment, since the cold cathode 10 is adopted as the electron source, immediate operation and low power consumption are possible.

By the way, in each of the above-mentioned embodiments, the strong electric field drift layer 6 is constituted by the oxidized porous polycrystalline silicon layer, but the strong electric field drift layer 6 is nitrided by the porous polycrystalline silicon layer or oxynitrided. It may be composed of a porous polycrystalline silicon layer, or may be composed of another oxidized, nitrided or oxynitrided porous semiconductor layer. Here, when the strong electric field drift layer 6 is a nitrided porous polycrystalline silicon layer, each of the silicon oxide films 52 and 64 described in FIG. 4 becomes a silicon nitride film, and the strong electric field drift layer 6 is oxidized. When the nitrided porous polycrystalline silicon layer is used, each of the silicon oxide films 52 and 64 described in FIG. 4 becomes a silicon oxynitride film.

[0043]

According to the invention of claim 1, a strong electric field drift layer made of a porous semiconductor layer oxidized or nitrided or oxynitrided is interposed between a lower electrode and a surface electrode facing each other, and a strong electric field drift from the lower electrode. Electrons injected into the layer drift toward the surface electrode and are emitted through the surface electrode, and a cold cathode that focuses the electron beam emitted from the cold cathode. By adopting, it is possible to realize immediate operation and low power consumption, and further, a strong electric field drift layer composed of a porous semiconductor layer oxidized or nitrided or oxynitrided between a lower electrode and a surface electrode facing each other. Electrons emitted from the cold cathode with the interposition of are emitted along the normal direction of the surface electrode and the electron emission angle is smaller than that of the Spindt-type cold cathode. UNA first grid, easier to manufacture and requires without structure in which the second grid becomes easy and there is an effect that also controls the beam current becomes easy.

According to the invention of claim 2, in the invention of claim 1, since the beam current amount is controlled by controlling the potential of the lower electrode of the cold cathode, the beam current amount can be controlled only by the potential of the lower electrode, Since there is no influence of the electric field from the anode as in the conventional case, there is an effect that the beam current amount can be controlled with good controllability.

[Brief description of drawings]

FIG. 1 shows the first embodiment, (a) is a schematic configuration diagram of an electron gun, and (b) is a schematic sectional view of a cold cathode.

FIG. 2 is a cross-sectional view of main steps for explaining the method for manufacturing the cold cathode used in the above.

FIG. 3 is an operation explanatory view of the cold cathode used in the above.

FIG. 4 is an operation explanatory view of the cold cathode used in the above.

FIG. 5 is a schematic sectional view of a cold cathode according to a second embodiment.

FIG. 6 is a cross-sectional view of main steps for explaining the method for manufacturing the cold cathode used in the above.

FIG. 7 is an operation explanatory view of an example cathode used in the above.

FIG. 8 is a schematic configuration diagram showing a conventional example.

FIG. 9 is a schematic cross-sectional view showing an example of a conventional Spindt-type cathode.

FIG. 10 shows another example of a conventional Spindt-type cold cathode,
(A) is a schematic plan view and (b) is a schematic sectional view.

FIG. 11 is a schematic configuration diagram of an electron gun using the above Spindt-type cold cathode.

[Explanation of symbols]

1 n-type silicon substrate 2 Ohmic electrodes 6 Strong electric field drift layer 7 Surface electrode 10 Cold cathode 20 electrostatic lens G3 3rd grid G4 4th grid G5 Fifth Grid

Continued front page    (72) Inventor Takuya Komoda             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company (72) Inventor Yoshiaki Honda             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company (72) Inventor Takashi Hatai             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company (72) Inventor Tsutomu Kagehara             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company F-term (reference) 5C031 DD09                 5C041 AA08 AB03

Claims (2)

[Claims] 1. A strong electric field drift layer made of a porous semiconductor layer oxidized or nitrided or oxynitrided is interposed between a lower electrode and a surface electrode facing each other, and electrons injected from the lower electrode to the strong electric field drift layer are generated. An electron gun for a cathode ray tube, comprising: a cold cathode that drifts toward a surface electrode and is emitted through the surface electrode; and a focusing electrode that focuses an electron beam emitted from the cold cathode. 2. The electron gun for a cathode ray tube according to claim 1, wherein the beam current amount is controlled by controlling the potential of the lower electrode of the cold cathode.