JP3671875B2 - Field emission electron source - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a field emission electron source configured to emit an electron beam by field emission.
[0002]
[Prior art]
Conventionally, a field emission electron source has been proposed in which a strong electric field drift layer made of an oxidized or nitrided porous semiconductor layer is formed on one surface side of a conductive substrate, and a surface electrode is formed on the strong electric field drift layer. (For example, refer to JP-A-8-250766, JP-A-9-259795, JP-A-10-326557, JP2996642, JP2987140, etc.).
[0003]
As this type of field emission electron source, for example, one having the structure shown in FIG. 7 is known. In the field emission electron source 10 ′ having the configuration shown in FIG. 7, a strong electric field drift layer 6 made of an oxidized porous polycrystalline silicon layer is formed on the main surface side of an n-type silicon substrate 1 which is a conductive substrate. A surface electrode 7 made of a metal thin film is formed on the drift layer 6, and an ohmic electrode 2 is formed on the back surface of the n-type silicon substrate 1. In the example shown in FIG. 7, the non-doped polycrystalline silicon layer 3 is interposed between the n-type silicon substrate 1 and the strong electric field drift layer 6, but the n-type without the polycrystalline silicon layer 3 being interposed. A configuration in which a strong electric field drift layer 6 is formed on a silicon substrate 1 has also been proposed.
[0004]
In order to emit electrons from the field emission electron source 10 ′ having the configuration shown in FIG. 7, a collector electrode 21 disposed to face the surface electrode 7 is provided, and a vacuum is applied between the surface electrode 7 and the collector electrode 21. Then, while applying the DC voltage Vps between the surface electrode 7 and the n-type silicon substrate 1 so that the surface electrode 7 is on the high potential side (positive electrode) with respect to the n-type silicon substrate 1 (ohmic electrode 2), 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 set appropriately, electrons injected from the n-type silicon substrate 1 drift through the strong electric field drift layer 6 and are emitted through the surface electrode 7 (note that the one-dot chain line in FIG. Electrons e emitted through the electrode 7^-Shows the flow). The surface electrode 7 is made of a material having a small work function (for example, gold), and the film thickness of the surface electrode 7 is set to about 10 nm to 15 nm.
[0005]
In the field emission electron source 10 ′ having the above-described configuration, the current flowing between the surface electrode 7 and the ohmic electrode 2 is called a diode current Ips, and the current flowing between the collector electrode 21 and the surface electrode 7 (that is, If the current due to the electron beam emitted through the surface electrode 7 is called an emission current (emission electron current) Ie (see FIG. 7), the ratio of the emission current Ie to the diode current Ips (= Ie / Ips) is large. The higher the electron emission efficiency. In the field emission electron source 10, electrons can be emitted even when the DC voltage Vps applied between the surface electrode 7 and the ohmic electrode 2 is set to a low voltage of about 10 to 20 V, and the DC voltage Vps is large. As the emission current Ie increases.
[0006]
In this field emission type electron source 10 ', the electron emission characteristic is less dependent on the degree of vacuum, and a popping phenomenon does not occur during electron emission, and electrons can be stably emitted with high electron emission efficiency.
[0007]
In the field emission electron source 10 ′ described above, the strong electric field drift layer 6 deposits a non-doped polycrystalline silicon layer on the n-type silicon substrate 1 which is a conductive substrate, and then anodizes the polycrystalline silicon layer. It is formed by oxidizing the porous polycrystalline silicon layer (porous polycrystalline silicon layer) at a temperature of, for example, 900 ° C. by a rapid heating method.
[0008]
As shown in FIG. 8, the strong electric field drift layer 6 formed as described above includes at least columnar polycrystalline silicon grains (semiconductor crystals) 51 and a thin silicon oxide film formed on the surface of the grains 51. 52, a nanometer-order silicon microcrystal 63 interposed between the grains 51, and a silicon oxide film 64 which is an oxide film formed on the surface of the silicon microcrystal 63 and having a film thickness smaller than the crystal grain size of the silicon microcrystal 63. It is thought that it is composed of That is, in the strong electric field drift layer 6, the surface of each grain contained in the polycrystalline silicon layer before the anodic oxidation treatment is made porous so that the crystalline state is maintained at the center of each grain. . Therefore, most of the electric field applied to the strong electric field drift layer 6 is concentrated on the silicon oxide film 64, and the injected electrons are accelerated by the strong electric field applied to the silicon oxide film 64, and between the grains 51 are brought to the surface. Since it drifts in the direction of the arrow in FIG. 8 (upward in FIG. 8), the electron emission efficiency can be improved. Here, in the field emission electron source 10 ′ having such a strong electric field drift layer 6, the heat generated in the strong electric field drift layer 6 is released through the grains 51, thereby preventing the occurrence of a popping phenomenon during electron emission. It is thought that. The electrons reaching the surface of the strong electric field drift layer 6 are considered to be hot electrons, and are easily tunneled through the surface electrode 7 and emitted into the vacuum.
[0009]
In the above-mentioned field emission electron source 10 ′, an n-type silicon substrate is used as the conductive substrate. However, as shown in FIG. 9, the conductive layer 12 is formed on one surface of the insulating substrate 11 ′ made of a glass substrate. A field emission electron source 10 ″ using the one formed with the same structure as that of the field emission electron source 10 ′ shown in FIG. 7 is denoted by the same reference numeral. The description is omitted.
[0010]
In order to emit electrons from the field emission electron source 10 ″ having the configuration shown in FIG. 9, a collector electrode 21 disposed opposite to the surface electrode 7 is provided, and a vacuum is applied between the surface electrode 7 and the collector electrode 21. Thus, the DC voltage Vps is applied between the surface electrode 7 and the conductive layer 12 so that the surface electrode 7 is on the high potential side (positive electrode) with respect to the conductive layer 12, and the collector electrode 21 is connected to the surface electrode 7. A DC voltage Vc is applied between the collector electrode 21 and the surface electrode 7 so as to be on the high potential side.If each DC voltage Vps, Vc is appropriately set, electrons injected from the conductive layer 12 are applied. Drifts in the strong electric field drift layer 6 and is emitted through the surface electrode 7 (note that the one-dot chain line in FIG.^-Shows the flow. )
In the field emission electron source 10 ″ having the above-described configuration, 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 (that is, If the current due to the electron beam emitted through the surface electrode 7) is called an emission current (emission electron current) Ie (see FIG. 9), the ratio of the emission current Ie to the diode current Ips (= Ie / Ips) is The larger the value, the higher the electron emission efficiency. In this field emission type electron source 10 ″, electrons are generated even when the DC voltage Vps applied between the surface electrode 7 and the conductive layer 12 is set to a low voltage of about 10-20V. The emission current Ie increases as the DC voltage Vps increases.
[0011]
Further, when the field emission electron source 10 ″ shown in FIG. 9 is applied as an electron source of a display, for example, the configuration shown in FIG. 10 may be adopted.
[0012]
The display shown in FIG. 10 has a frame-like support between a rear plate (not shown) made of a flat glass substrate to which a field emission electron source 10 is bonded and a face plate 30 made of a flat glass substrate. The space between the rear plate and the face plate is maintained in a vacuum with a spacer (not shown) interposed. A collector electrode (transparent electrode) made of an ITO film is formed on the face plate 30 facing the field emission electron source 10, and the collector electrode facing the field emission electron source 10 is formed on the face facing the field emission electron source 10. , G, and B are formed with a plurality of pixels.
[0013]
The field emission electron source 10 shown in FIG. 10 includes an insulating substrate 11 ′ made of a glass substrate, a lower electrode 12a made of a plurality of conductive layers arranged on one surface of the insulating substrate 11 ′, A strong electric field drift layer 6 having a drift portion 6a made of a plurality of oxidized porous polycrystalline silicon layers formed so as to overlap with the lower electrode 12a and a separation portion 6b made of a polycrystalline silicon layer filling between the drift portions 6a. And a plurality of surface electrodes 7 formed on the strong electric field drift layer 6 in a direction intersecting with the lower electrode 12a.
[0014]
In this field emission type electron source 10, strong electric force is provided between a plurality of lower electrodes 12 a arranged on one surface of an insulating substrate 11 ′ and a plurality of surface electrodes 7 formed on the strong electric field drift layer 6. Since the drift portion 6a of the electric field drift layer 6 is sandwiched, the surface electrode 7 and the lower portion are selected by applying a voltage between the selected pair of the surface electrode 7 and the lower electrode 12a as appropriate. A strong electric field acts only on the drift portion 6a at a portion corresponding to the intersection with the electrode 12a to emit electrons. That is, this corresponds to the arrangement of the electron source element 10a composed of the surface electrode 7, the lower electrode 12a, and the drift portion 6a at the lattice point of the matrix (lattice) composed of the surface electrode 7 and the lower electrode 12a. By selecting a set of the surface electrode 7 and the lower electrode 12a to be emitted, electrons can be emitted from the desired electron source element 10a. Here, the drift portion 6a is considered to have the same configuration as that of FIG. That is, the drift portion 6 a includes at least columnar polycrystalline silicon grains (semiconductor crystals) 51, a thin silicon oxide film 52 formed on the surface of the grains 51, and nanometer-order silicon microcrystals interposed between the grains 51. 63 and a silicon oxide film 64 which is an oxide film formed on the surface of the silicon microcrystal 63 and having a film thickness smaller than the crystal grain size of the silicon microcrystal 63.
[0015]
By the way, in the above-described display, since the airtight space surrounded by the face plate 30, the rear plate, and the supporting spacer is kept in a vacuum state, the face plate 30 and the rear plate can be caused by atmospheric pressure even if the screen area is increased. In addition to the supporting spacer, a reinforcing spacer (not shown) is interposed between the field emission electron source 10 and the face plate 30.
[0016]
[Problems to be solved by the invention]
By the way, in the display using the field emission electron source 10 described above, a reduction in thickness and an increase in screen area are expected. In such a display, after the field emission electron source 10 is bonded to the rear plate, it is necessary to evacuate after interposing a reinforcing spacer between the field emission electron source 10 and the face plate 30, The reinforcing spacers need to be arranged between adjacent pixels, and it is necessary to make them difficult to see from the outside. Therefore, when the spacing between the pixels is, for example, about 50 μm to 100 μm, the reinforcing spacers in the pixel juxtaposition direction And the height of the reinforcing spacer in the thickness direction of the insulating substrate 11 ′ is set to about several mm, and there is a problem that it takes time to arrange the reinforcing spacer.
[0017]
The present invention has been made in view of the above reasons, and an object of the present invention is to provide a field emission electron source capable of simplifying a display assembly process when used as an electron source of a display.
[0018]
[Means for Solving the Problems]
  In order to achieve the above object, an invention according to claim 1 includes an insulating substrate and a plurality of electron source elements that are formed on one surface side of the insulating substrate and emit electrons. From a ceramic substrate in which reinforcing spacers made of ceramic projecting in the thickness direction from the one surface are integrally formed by a sintering method so as to keep a distance between a face plate spaced apart on the surface side and opposed to a specified distance. Become, Insulating substrateIs made of SiC or AlN, and the reinforcing spacer ceramic is ZrO.₂Or Al₂O₃Or a step of disposing a separate reinforcing spacer between the field emission electron source and the face plate at the time of assembly as in the prior art when used as an electron source of a display. This eliminates the need to position and fix separate reinforcing spacers for the field emission electron source and the face plate, simplifying the display assembly process and increasing the display area. Becomes easier. In addition, since ceramics such as SiC or AlN have higher thermal conductivity than glass, the heat generated in the electron source element can be dissipated more efficiently than when a glass substrate is used as an insulating substrate as in the prior art. The reliability as an electron source can be improved. The ceramic substrate on which the reinforcing spacer is integrally formed can be easily formed by a sintering method, and the reinforcing spacer can easily correspond to various shapes.
[0019]
According to a second aspect of the present invention, in the first aspect of the invention, the electron source element includes a lower electrode formed on the one surface side of the insulating substrate, a surface electrode facing the lower electrode in the thickness direction, A drift portion made of an oxidized or nitrided or oxynitrided porous semiconductor layer interposed between the lower electrode and the surface electrode is provided, and a voltage is applied between the surface electrode and the lower electrode with the surface electrode as a high potential side. Sometimes, electrons injected from the lower electrode due to an electric field acting on the drift portion drift through the drift portion and are emitted through the surface electrode. Therefore, the emission direction of the electron beam emitted from the electron source element is normal to the surface electrode. Since it is easy to align in the direction, there is no need to provide a complicated shadow mask or electron converging lens, the display can be thinned, and the reinforcing spacer from the above surface of the insulating substrate It is possible to reduce the projection height.
[0020]
According to a third aspect of the present invention, in the second aspect of the present invention, since the lower electrode of the ceramic substrate is integrally formed with the insulating substrate, the lower electrode can be formed regardless of the reinforcing spacer. Therefore, the layout design of the lower electrode is facilitated.
[0021]
According to a fourth aspect of the present invention, in the first to third aspects of the invention, the insulating substrate also serves as a rear plate for forming an airtight space in which the electron source elements are accommodated together with the face plate. The number of parts can be reduced, the number of assembly steps can be reduced, and the cost can be reduced.
[0023]
  Also, Insulating substrateIs made of SiC or AlN, Insulating substrateIs Al₂O₃Compared with the case where it consists of, heat conductivity becomes high, and it becomes possible to efficiently radiate the heat generated in each electron source element to the outside.
[0024]
  Also reinforcedSpacerIs ZrO ₂ Or Al ₂ O ₃ Or SiC and highSince it is a resistor, charges are less likely to accumulate than when the reinforcing spacer is formed of an insulator, and the reinforcing spacer is less likely to be charged up due to electron scattering on the face plate side. Reliability can be increased.
[0026]
  Claim5Claimed inventionClaims 1 to 4In the present invention, the reinforcing spacer has a resistivity of 10³-10⁹It is characterized by being Ωcm, which is a preferred embodiment.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
Hereinafter, a display using the field emission electron source of the present embodiment will be described with reference to FIGS.
[0028]
In the display having the configuration shown in FIG. 1, a field emission electron source 10 and a face plate 30 made of a flat glass substrate are arranged to face each other. Although not shown, a collector electrode (transparent electrode) made of an ITO film is formed on the face plate 30 facing the field emission electron source 10, and the field emission electron source 10 in the collector electrode and A plurality of pixels composed of three phosphor cells of R, G, and B are formed on the opposite surface.
[0029]
In the field emission electron source 10, a strong electric field drift layer 6 is laminated on one surface side of an insulating substrate 11 in which a plurality of lower electrodes 12 a are arranged on one surface side, and on the strong electric field drift layer 6. A plurality of surface electrodes 7 formed in a direction orthogonal to the lower electrode 12a are provided. That is, the lower electrode 12a and the surface electrode 7 are disposed so as to be orthogonal to each other with the strong electric field drift layer 6 interposed therebetween. Here, the strong electric field drift layer 6 includes a drift portion 6a made of a plurality of oxidized porous polycrystalline silicon layers formed at each of the intersecting portions of the plurality of lower electrodes 12a and the plurality of surface electrodes 7, It is comprised by the isolation | separation part 6b which consists of a polycrystalline-silicon layer which fills between the drift parts 6a. The lower electrode 12a is embedded in the insulating substrate 11 with the surface on the one surface side of the insulating substrate 11 exposed, and the one surface of the insulating substrate 11 and the surface of the lower electrode 12a Are on the same plane. The lower electrode 12a is formed in a strip shape, and pads 27 are formed on both ends in the longitudinal direction. Further, the surface electrode 7 is formed in a strip shape, and is connected to the pad 28 at both ends in the longitudinal direction.
[0030]
In the field emission electron source 10, a plurality of lower electrodes 12 a arranged on one surface side of the insulating substrate 11 and a plurality of surface electrodes 7 formed on the strong electric field drift layer 6 are provided. Since the drift portion 6a of the strong electric field drift layer 6 is sandwiched, by selecting a set of the surface electrode 7 and the lower electrode 12a as appropriate and applying a voltage between the selected sets, the selected surface electrode 7 and A strong electric field acts only on the drift portion 6a corresponding to the intersection with the lower electrode 12a to emit electrons. That is, this corresponds to the arrangement of the electron source element 10a composed of the surface electrode 7, the lower electrode 12a, and the drift portion 6a at the lattice point of the matrix (lattice) composed of the surface electrode 7 and the lower electrode 12a. By selecting a set of the surface electrode 7 and the lower electrode 12a to be emitted, electrons can be emitted from the desired electron source element 10a. Here, the drift portion 6a is considered to have the same configuration as that of FIG. That is, the drift portion 6 a includes at least columnar polycrystalline silicon grains (semiconductor crystals) 51, a thin silicon oxide film 52 formed on the surface of the grains 51, and nanometer-order silicon microcrystals interposed between the grains 51. 63 and a silicon oxide film 64 which is an insulating film formed on the surface of the silicon microcrystal 63 and having a film thickness smaller than the crystal grain size of the silicon microcrystal 63. Here, each grain 51 is considered to be formed along the thickness direction of the insulating substrate 11. In the above-described electron source element 10a, since the emission direction of the electron beam emitted through the surface electrode 7 is easily aligned with the normal direction of the surface electrode 7, it is not necessary to provide a complicated shadow mask or an electron focusing lens, and the display is thin. Can be realized. Further, since electrons can be emitted even when the voltage applied between the surface electrode 7 and the lower electrode 12a is set to a low voltage of about 10 to 20 V, power consumption can be reduced.
[0031]
By the way, in this embodiment, the thing of a structure as shown in FIG. In other words, in the present embodiment, the insulating substrate 11 is insulated from the one surface so that the distance between the insulating substrate 11 and the face plate 30 disposed opposite to the one surface side is kept at a specified distance. The reinforcing substrate 11b protruding in the thickness direction of the conductive substrate 11 and the ceramic substrate in which the lower electrodes 12a are integrally formed are used. Each reinforcing spacer 11b in the present embodiment is formed in a direction perpendicular to the lower electrode 12a, and protrudes toward the face plate 30 in such a manner that the separating portion 6b of the strong electric field drift layer 6 is divided. Here, the reinforcing spacer 11b is formed in a strip shape, the thickness in the extending direction of the lower electrode 12a is about several μm according to the interval between the pixels, and the height in the thickness direction of the insulating substrate 11 is several mm. What is necessary is just to set to a grade. Such a ceramic substrate can be easily formed by a sintering method or the like, and the shape of the reinforcing spacer 11b can easily correspond to various shapes.
[0032]
Thus, in the field emission electron source 10 according to the present embodiment, the reinforcing spacer 11b is integrally formed on the insulating substrate 11, and the field emission electron source 10 is reinforced after the field emission electron source 10 is formed. Since it is not necessary to position the spacer 11b for the display, a step of disposing a separate reinforcing spacer between the field emission electron source 10 and the face plate 30 during assembly as in the prior art when used as an electron source of a display. Is no longer necessary. In other words, the step of positioning and fixing separate reinforcing spacers with respect to the field emission electron source 10 and the face plate 30 is not necessary, so that the display assembly process can be simplified and the display can be easily increased in area. become.
[0033]
  In this embodiment, the thickness is set so that the insulating substrate 11 can be used as a rear plate, and the insulating substrate 11 is an electron together with the face plate 30 and a supporting spacer (not shown). Since it also serves as a rear plate for forming an airtight space in which the source element 10a is accommodated, the number of parts can be reduced, the number of assembly steps can be reduced, and the cost can be reduced. Where the insulating substrate11A material having a small thermal expansion coefficient with the face plate 30 (for example, Al₂O₃) Due to the difference in thermal expansion coefficient between the insulating substrate 11 and the face plate 30 in the assembly process.And insulating substrate 11It is possible to prevent cracking. Al₂O₃,AlNSince ceramics such as SiC have higher thermal conductivity than glass, heat generated in the electron source element 10a can be radiated more efficiently than in the case where an insulating substrate 11 ′ made of a glass substrate is used as in the prior art. The reliability as an electron source can be improved. In particular, if the main component of the insulating substrate 11 is SiC or AlN, the main component is Al.₂O₃Compared with the case, the thermal conductivity is increased, and the heat dissipation can be further improved. Here, the thermal conductivity of glass is ˜1 W / mK, the thermal conductivity of SiC is 60 to 70 W / mK, the thermal conductivity of AlN is ˜80 W / mK,Al ₂ O ₃ The thermal conductivity of is 10 to 40 W / mK.
[0034]
Note that the degree of vacuum in the airtight space surrounded by the face plate 30, the insulating substrate 10, and the supporting spacer is 10 degrees.^-FourPa-10¹It is set to about Pa.
[0035]
By the way, if the reinforcing spacer 11b is an insulator, when electrons are scattered on the face plate 30 side, the reinforcing spacer 11b is charged up and a desired voltage can be applied between the collector electrode and the surface electrode 7. There is a risk of disappearing. In order to solve this type of problem, at least the reinforcing spacer 11b of the ceramic substrate may be set to a high resistance. If the reinforcing spacer 11b has a high resistance, charges are less likely to accumulate than when the reinforcing spacer 11b is formed of an insulator, and the reinforcing spacer 11b is caused by scattering of electrons on the face plate 30 side. Charge-up is less likely to occur, and display reliability can be improved. Here, as a main component of the high-resistance reinforcing spacer 11b, ZrO₂, Al₂O_Three, SiC may be selected as appropriate, and the resistivity of the reinforcing spacer 11b is 10^Three-10⁹It is desirable to set to about Ωcm.
[0036]
In this embodiment, as shown in FIGS. 1 and 2, since the ceramic substrate in which the reinforcing spacer 11b and the lower electrode 12a are integrally formed on the insulating substrate 11 is used, the lower portion is used regardless of the reinforcing spacer 11b. Since the electrode 12a can be formed, there is an advantage that the layout design of the lower electrode 12a becomes easy. However, the lower electrode 12a is not necessarily formed integrally with the insulating substrate 11, and for example, as shown in FIG. A ceramic substrate in which only the reinforcing spacer 11b is integrally formed on the insulating substrate 11 may be used.
[0037]
(Embodiment 2)
The basic configuration of the field emission electron source 10 of the present embodiment is substantially the same as that of the first embodiment. As shown in FIGS. 4 and 5, a plurality of prismatic reinforcing spacers 11 b are integrated as an insulating substrate 11. The formed ceramic substrate is used, and the difference is that the lower electrode 12a made of a metal material (for example, Cr, W, etc.) is formed so as to protrude from the one surface of the insulating substrate 11. Here, the reinforcing spacer 11b protrudes toward the face plate 30 (see FIG. 1) described in the first embodiment so as to penetrate the separating portion 6b of the strong electric field drift layer 6. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.
[0038]
In this embodiment, since the reinforcing spacer 11b is formed in a prismatic shape, the lower electrode patterned in a predetermined shape on the one surface side of the insulating substrate 11 integrally formed with the reinforcing spacer 11b. 12a can be easily formed, and it is possible to easily cope with changes in the pattern and material of the lower electrode 12a.
[0039]
(Embodiment 3)
The substrate configuration of the field emission electron source 10 of the present embodiment is substantially the same as that of the second embodiment, and as shown in FIG. 6, as shown in FIG. The difference is that 12b is formed. Here, the lower electrode 12a is formed of n-type polycrystalline silicon, and the insulating portion 12b is formed of non-doped polycrystalline silicon. In this embodiment, after forming a non-doped polycrystalline silicon layer on the one surface side of the insulating substrate 11 integrally formed with the reinforcing spacer 11b, the n-type multi-layer is utilized by using a lithography technique, an ion implantation technique, and the like. By forming the lower electrode 12a made of crystalline silicon, the remaining portion becomes the insulating portion 12b made of non-doped polycrystalline silicon. The strong electric field drift layer 6 is formed by forming a non-doped polycrystalline silicon layer so as to cover the lower electrode 12a and the insulating portion 12b, and then subjecting the polycrystalline silicon layer to anodic oxidation or oxidation. Drift portion 6a is formed.
[0040]
Therefore, in this embodiment, since the insulating portion 12b is formed between the adjacent lower electrodes 12a, the flatness of the surface of the strong electric field drift layer 6 can be improved, and disconnection of the surface electrode 7 is prevented. be able to.
[0041]
By the way, in each said embodiment, although the drift part 6a of the strong electric field drift layer 6 is formed with the oxidized porous polycrystalline silicon layer, the drift part 6a is formed with the porous polycrystalline silicon layer nitrided or oxynitrided. Alternatively, a porous semiconductor layer other than the porous polycrystalline silicon layer may be formed by oxidation, nitridation, or oxynitridation. In the case where the drift portion 6a is a nitrided porous polycrystalline silicon layer, the silicon oxide films 52 and 64 described with reference to FIG. 8 are both silicon nitride films, and the drift portion 6a is oxynitrided porous polycrystalline silicon. In the case of layers, the silicon oxide films 52 and 64 are both silicon oxynitride films.
[0042]
Further, each of the electron source elements 10a described above is formed for each subpixel made of any of R, G, and B phosphors provided on the face plate 30 facing the field emission electron source 10. Therefore, if the surface electrode 7 and the lower electrode 12a are formed only in a portion overlapping the drift portion 6a in the thickness direction of the insulating substrate 11 and a bus electrode made of a low-resistance conductive material is provided, the selected electron The delay time until the electron beam is emitted from the source element 10a can be shortened, and the reduction and variation of the emission current due to the voltage drop in the wiring can be suppressed.
[0043]
【The invention's effect】
  The invention of claim 1 includes an insulating substrate and a plurality of electron source elements that are formed on one surface side of the insulating substrate and emit electrons, and the insulating substrate is disposed opposite to and spaced apart from the one surface side. A reinforcing spacer made of ceramic that protrudes in the thickness direction from the one surface so as to keep a distance between the face plate and the face plate to be a predetermined distance is made of a ceramic substrate integrally formed by a sintering method., Insulating substrateIs made of SiC or AlN, and the reinforcing spacer ceramic is ZrO.₂Or Al₂O₃Alternatively, when it is made of SiC and used as an electron source for a display, a step of disposing a separate reinforcing spacer between the field emission electron source and the face plate at the time of assembly as in the prior art becomes unnecessary. This eliminates the need for positioning and fixing separate reinforcing spacers for the field emission electron source and the face plate, simplifying the display assembly process and facilitating an increase in the display area. effective. In addition, since ceramics such as SiC or AlN have higher thermal conductivity than glass, the heat generated by the electron source element can be dissipated more efficiently than when a glass substrate is used as an insulating substrate as in the prior art. The reliability of the electron source can be improved. The ceramic substrate on which the reinforcing spacer is integrally formed can be easily formed by a sintering method, and the reinforcing spacer can easily correspond to various shapes.
[0044]
According to a second aspect of the present invention, in the first aspect of the invention, the electron source element includes a lower electrode formed on the one surface side of the insulating substrate, a surface electrode facing the lower electrode in the thickness direction, A drift portion made of an oxidized or nitrided or oxynitrided porous semiconductor layer interposed between the lower electrode and the surface electrode is provided, and a voltage is applied between the surface electrode and the lower electrode with the surface electrode as a high potential side. Sometimes, electrons injected from the lower electrode due to an electric field acting on the drift portion drift through the drift portion and are emitted through the surface electrode. Therefore, the emission direction of the electron beam emitted from the electron source element is normal to the surface electrode. Since it is easy to align in the direction, there is no need to provide a complicated shadow mask or electron converging lens, the display can be thinned, and the reinforcing spacer from the above surface of the insulating substrate There is an effect that it is possible to reduce the projection height.
[0045]
According to a third aspect of the present invention, in the second aspect of the present invention, since the lower electrode of the ceramic substrate is integrally formed with the insulating substrate, the lower electrode can be formed regardless of the reinforcing spacer. effective. Therefore, the layout design of the lower electrode is facilitated.
[0046]
According to a fourth aspect of the present invention, in the first to third aspects of the invention, the insulating substrate also serves as a rear plate for forming an airtight space in which the electron source elements are accommodated together with the face plate. The number of parts can be reduced, the number of assembly processes can be reduced, and the cost can be reduced.
[0048]
  Also, Insulating substrateIs made of SiC or AlN, Insulating substrateIs Al₂O₃Compared with the case where it consists of, there exists an effect that heat conductivity becomes high and it becomes possible to thermally radiate the heat generated in each electron source element to the outside efficiently.
[0049]
  Also reinforcedSpacerIs ZrO ₂ Or Al ₂ O ₃ Or SiC and highSince it is a resistor, charges are less likely to accumulate than when the reinforcing spacer is formed of an insulator, and the reinforcing spacer is less likely to be charged up due to electron scattering on the face plate side. There is an effect that reliability can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a display using a field emission electron source according to a first embodiment.
FIG. 2 is a schematic perspective view of the main part of the above.
FIG. 3 is a schematic perspective view of a main part of another configuration example same as above.
4 is a schematic perspective view of a field emission electron source showing Embodiment 2. FIG.
FIG. 5 is a schematic perspective view of the main part of the above.
6 is a schematic cross-sectional view of a field emission electron source showing Embodiment 3. FIG.
FIG. 7 is an operation explanatory diagram of a field emission electron source showing a conventional example.
FIG. 8 is an operation explanatory diagram of the field emission electron source of the above.
FIG. 9 is an operation explanatory diagram of a field emission electron source showing another conventional example.
FIG. 10 is a schematic configuration diagram of a display using the above.
[Explanation of symbols]
6 Strong electric field drift layer
6a Drift part
6b Separation part
7 Surface electrode
10 Field emission electron source
10a Electron source element
11 Insulating substrate
11b Spacer
12a Lower electrode

Claims (5)

An insulating substrate and a plurality of electron source elements that are formed on one surface side of the insulating substrate and emit electrons, and the insulating substrate is spaced from the one surface side and is opposed to a face plate that is disposed opposite to the face plate. The reinforcing spacer made of ceramic that protrudes in the thickness direction from the one surface so as to keep the distance at a specified distance is made of a ceramic substrate integrally formed by a sintering method , the insulating substrate is made of SiC or AlN, and the reinforcing spacer A field emission electron source, wherein the ceramic is made of ZrO _2, Al ₂ O _3, or SiC.   The electron source element includes a lower electrode formed on the one surface side of the insulating substrate, a surface electrode facing the lower electrode in the thickness direction, and an oxidation or nitridation interposed between the lower electrode and the surface electrode. Or a drift portion made of an oxynitrided porous semiconductor layer, which is injected from the lower electrode by an electric field acting on the drift portion when a voltage is applied between the surface electrode and the lower electrode with the surface electrode as a high potential side. 2. The field emission electron source according to claim 1, wherein the electrons drift through the drift portion and are emitted through the surface electrode.   3. The field emission electron source according to claim 2, wherein the ceramic substrate has the lower electrode formed integrally with the insulating substrate.   4. The field emission according to claim 1, wherein the insulating substrate also serves as a rear plate for forming an airtight space in which the electron source elements are accommodated together with the face plate. Type electron source. 5. The field emission electron source according to claim 1 , wherein the reinforcing spacer has a resistivity of 10 ³ to 10 ⁹ Ωcm .

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