WO2006075405A1

WO2006075405A1 - Electron emitting element

Info

Publication number: WO2006075405A1
Application number: PCT/JP2005/000500
Authority: WO
Inventors: Yukihisa Takeuchi; Tsutomu Nanataki; Iwao Ohwada; Takayoshi Akao
Original assignee: Ngk Insulators, Ltd.
Priority date: 2005-01-17
Filing date: 2005-01-17
Publication date: 2006-07-20
Also published as: CN1879184A

Abstract

An electron emitting element (10A) is provided with an emitter part (12) composed of a dielectric material, and an upper electrode (14) and a lower electrode (16) whereupon a driving voltage (Va) is applied for electron emission. The upper electrode (14) is formed on an upper plane of the emitter part (12), and the lower electrode (16) is formed on a lower plane of the emitter part (12). The upper electrode (14) is provided with a plurality of penetrating parts (20) from which the emitter part (12) is exposed. In the upper electrode (14), a plane facing the emitter part (12) at a circumference part (26) of the penetrating part (20) is separated from the emitter part (12).

Description

Specification

Electron emitter

Technical field

[0001] The present invention relates to an electron-emitting device having a first electrode and a second electrode formed in a substance serving as an emitter.

Background art

[0002] Recently, an electron-emitting device has a force sword electrode and an anode electrode, and is applied to various applications such as a field emission display (FED) and a backlight. When applied to FED, a plurality of electron-emitting devices are two-dimensionally arranged, and a plurality of phosphors for these electron-emitting devices are arranged with a predetermined interval.

[0003] As a conventional example of this electron-emitting device, for example, Patent Documents 1 to 15 all use a dielectric as a substance that serves as an emitter. However, there is a problem that fine processing is required, a high voltage must be applied for electron emission, and the panel manufacturing process is complicated and the manufacturing cost increases.

[0004] Consequently, it has been considered that a substance serving as an emitter is composed of a dielectric, and various theories are described in the following Non-Patent Documents 1 to 13 regarding electron emission from the dielectric.

Patent Document 1: JP-A-1-311533

Patent Document 2: JP-A-7-147131

Patent Document 3: Japanese Patent Laid-Open No. 2000-285801

Patent Document 4: Japanese Patent Publication No. 46-20944

Patent Document 5: Japanese Patent Publication No. 44-26125

Non-Patent Document 1: Yasuoka, Ishii, "Pulse electron source using a ferroelectric cathode" Applied Physics No. 68 卷 No. 5, p546-550 (1999)

Non-Patent Literature 2: VFPuchkarev, GAMesyats, On the mechanism of emission from the ferroelectric ceramic cathode, J. Appl. Phys., Vol. 78, No. 9, 1 November, 1995, p. 5633-5637 Non-Patent Document 3: H.Riege, Electron emission ferroelectrics-a review, Nucl. Instr. And Meth.A340, p. 80-89 (1994)

Disclosure of the invention

Problems to be solved by the invention

Incidentally, in the conventional electron-emitting device 200, as shown in FIG. 39, when the upper electrode 204 and the lower electrode 206 are formed on a substance (emitter portion) 202 serving as an emitter, particularly on the emitter portion 202. Thus, the upper electrode 204 is formed in close contact with the upper electrode 204. The electric field concentration point is a force that is the triple point of the upper electrode 204Z emitter 202Z vacuum. In this case, the peripheral portion of the upper electrode 204 corresponds.

[0006] However, since the peripheral portion of the upper electrode 204 is in close contact with the emitter portion 202, there is a problem that the energy required for emitting electrons with a small electric field concentration is small. In addition, since the electron emission location is limited to the peripheral portion of the upper electrode 204, the overall electron emission characteristics vary, making it difficult to control the electron emission and lowering the electron emission efficiency. There is also.

[0007] The present invention has been made in view of such problems, and can easily generate a high electric field concentration, and can increase the number of electron emission locations. An object of the present invention is to provide an electron-emitting device that can achieve high output and high efficiency and can be driven at a low voltage.

[0008] Further, another object of the present invention is simply applied to a display having a plurality of electron-emitting devices arranged in accordance with a plurality of pixels and performing image display by electron emission from each electron-emitting device. An object of the present invention is to provide an electron-emitting device that can be used.

Means for solving the problem

[0009] An electron-emitting device according to the present invention includes a substance serving as an emitter composed of a dielectric, and a first electrode and a second electrode to which a driving voltage for electron emission is applied, The first electrode is formed on a first surface of the substance serving as the emitter, and the second electrode is formed on a second surface of the substance serving as the emitter, and at least the first electrode. Has a plurality of penetrating portions from which the substance serving as the emitter is exposed, and of the first electrode, the surface force facing the substance serving as the emitter in the peripheral portion of the penetrating portion The material force serving as the emitter Spaced apart It is characterized by.

[0010] First, a drive voltage is applied between the first electrode and the second electrode. This drive voltage is, for example, a pulse voltage or an AC voltage, which is higher or lower than the reference voltage (e.g. OV) over time, from a voltage level lower or higher than the reference voltage. It is defined as a voltage that changes rapidly at a level.

[0011] Further, a triple junction is formed at a contact point between the first surface of the substance serving as an emitter, the first electrode, and a medium (for example, a vacuum) around the electron-emitting device. here

A triple junction is defined as an electric field concentrator formed by the contact between the first electrode and the substance serving as an emitter and a vacuum. The triple junction also includes the triple point where the first electrode, the substance serving as the emitter, and the vacuum exist as one point. In the present invention, the triple junction is formed in the peripheral portion of the plurality of through portions and the peripheral portion of the first electrode. Therefore, when the driving voltage as described above is applied between the first electrode and the second electrode, electric field concentration occurs in the triple junction described above.

[0012] Then, when an output period having a voltage level higher or lower than the reference voltage is a first output period, and an output period having a voltage level lower or higher than the reference voltage is a second output period, first, In the output period of 1, the electric field concentration in one direction occurs, for example, in the triple junction described above. For example, of the substance serving as an emitter, the portion corresponding to the penetrating portion of the first electrode and the peripheral edge of the first electrode Electrons are accumulated in the vicinity of the part. At this time, the first electrode functions as an electron supply source.

[0013] In the next second output period, when the voltage level of the drive voltage changes suddenly, electric field concentration in the reverse direction occurs at the triple junction, and among the substances serving as the emitter, the electron Electrons are emitted through the penetrating part from the part where the ions were accumulated. Of course, electrons are also emitted from the vicinity of the outer periphery of the first electrode.

In another electron emission method, first, in the first output period, preparation for electron emission (for example, polarization in one direction of a substance serving as an emitter) is performed. If the voltage level of the drive voltage changes suddenly during the second output period, electric field concentration occurs at the triple junction described above, and primary electrons are emitted from the first electrode due to this electric field concentration. Part of the material that becomes the emitter It will collide with the vicinity of the outer periphery of the first electrode. As a result, secondary electrons (including reflected electrons of the primary electrons) are emitted from the part where the primary electrons collide. That is, in the initial stage of the second output period, secondary electrons are emitted from the vicinity of the through hole and the outer periphery of the first electrode.

[0015] In this electron-emitting device, first, since the plurality of through portions are formed in the first electrode, electrons are evenly emitted from each through portion and the vicinity of the outer periphery of the first electrode, Variations in the overall electron emission characteristics are reduced, control of electron emission is facilitated, and electron emission efficiency is increased.

[0016] Further, the present invention provides a shape in which a gap is formed between a surface of the first electrode facing the substance serving as the emitter at a peripheral portion of the penetrating part and the substance serving as the emitter. Therefore, when a drive voltage is applied, electric field concentration is likely to occur in the gap portion. This leads to a high efficiency of electron emission, and a low drive voltage (electron emission at a low voltage level) can be realized.

As described above, according to the present invention, a gap is formed between the surface of the first electrode facing the substance serving as the emitter in the peripheral portion of the penetrating part and the substance serving as the emitter. In addition, since the peripheral portion of the through-hole in the first electrode has a hook shape (flange shape), the electric field concentration in the gap portion increases, and the hook-like portion (penetration) Electrons are easily generated from the peripheral part of the part. This leads to higher output and higher efficiency of electron emission, and lower drive voltage can be realized. In addition, either the method of emitting electrons accumulated in a substance serving as an emitter or the method of emitting secondary electrons by colliding primary electrons from the first electrode with a material serving as an emitter. Since the peripheral portion of the through portion of the electrode functions as a gate electrode (control electrode, focus electron lens, etc.), the straightness of the emitted electrons can be improved. This is advantageous in reducing crosstalk when, for example, a large number of electron-emitting devices are arranged as an electron source for display.

As described above, in the present invention, high electric field concentration can be easily generated. However, the number of electron emission portions can be increased, and high output and high efficiency can be achieved for electron emission. In addition, low voltage drive (low power consumption) is also possible.

[0019] In the configuration, at least the first surface of the substance serving as the emitter is Concavities and convexities are formed by a grain boundary of the dielectric, and the first electrode may have the penetrating portion formed in a portion corresponding to the concave portion in the grain boundary of the dielectric.

[0020] Thereby, in the first electrode, the surface of the peripheral portion of the through portion that faces the substance serving as the emitter is separated from the material force serving as the emitter, that is, the periphery of the through portion. It is possible to easily realize a configuration in which a gap is formed between the surface of the portion facing the substance serving as the emitter and the substance serving as the emitter.

[0021] Further, in the above configuration, the first surface of the substance serving as the emitter is formed between a surface of the first electrode facing the substance serving as the emitter in the peripheral portion of the penetrating portion. The maximum angle Θ is preferably 1 ° ≤ Θ ≤60 °. Further, in the above configuration, in the vertical direction between the first surface of the substance serving as the emitter and the surface of the first electrode facing the substance serving as the emitter in the periphery of the through portion. The maximum spacing along the d force is preferably 0 / zm <d≤m. With these configurations, the degree of electric field concentration in the gap portion can be further increased, and high output and high efficiency with respect to electron emission, and low drive voltage can be efficiently achieved.

[0022] In the above configuration, a floating electrode may exist in a portion corresponding to the penetrating portion of the first surface of the substance serving as the emitter. In this case, since the floating electrode also serves as an electron supply source, a large number of electrons can be emitted to the outside through the through portion in the electron emission stage (the second output period described above).

[0023] Further, in the above configuration, the through portion may be a hole. Of the substance serving as an emitter, the part where the polarization is reversed or changed in accordance with the drive voltage applied between the first electrode and the second electrode is the part immediately below where the first electrode is formed (the first part). 1) and the inner peripheral force of the penetrating part (second part) corresponding to the region facing inward of the penetrating part, especially the second part is the drive voltage level and electric field concentration It will change depending on the degree. Therefore, in the present invention, the average diameter of the holes is preferably 0.1 m or more and 10 μm or less. Within this range, there is almost no variation in the electron emission distribution emitted through the penetrating portion, and electrons can be emitted efficiently.

[0024] When the average diameter of the holes is less than 0.1 μm, the region for accumulating electrons is narrowed and the amount of electrons emitted is reduced. Of course, it is possible to provide many holes, but the difficulty Along with this, there is a concern that the manufacturing cost is increased. When the average diameter of the holes exceeds 10 m, the ratio (occupancy) of the portion (second portion) contributing to electron emission in the exposed portion of the substance serving as the emitter is reduced. The release efficiency of the is reduced.

[0025] Further, in the above configuration, the through portion may be a notch or a comb-shaped notch. In this case, the average width of the notches is preferably 0.1 m or more and 10 μm or less.

[0026] In the above configuration, the through portion may be a slit having an arbitrary shape. In this case, the average width of the slit is preferably 0.1 m or more and 10 μm or less.

[0027] In addition, an electron-emitting device according to the present invention includes a substance serving as an emitter made of a dielectric, a first electrode formed so as to be in contact with the first surface of the substance serving as the emitter, and A second electrode formed so as to be in contact with the second surface of the substance serving as the emitter, and at least the first electrode has a plurality of through portions through which the substance serving as the emitter is exposed. In the electrical operation, the first electrode is formed by a capacitor made of a substance serving as the emitter between the first electrode and the second electrode, and the plurality of through portions formed in the first electrode. And an aggregate of a plurality of capacitors formed between the substance serving as the emitter.

[0028] That is, a gap is formed between a surface of the peripheral portion of the penetrating portion facing the emitter material and the emitter material, and an aggregate of capacitors is formed by the plurality of gaps. Will be. In this case, the capacitance value of the capacitor due to the gap is relatively small, and most of the applied voltage is applied to the gap due to the partial pressure with the capacitor due to the substance serving as an emitter. High output is realized. In addition, the aggregate of these capacitors has a structure in which they are connected in series to a capacitor made of a substance that serves as an emitter. Therefore, the overall capacitance value is smaller than the capacitance value of the capacitor due to the substance serving as the emitter. From this, it is possible to obtain desirable characteristics that electron emission is high output and overall power consumption is small.

[0029] In addition, the electron-emitting device according to the present invention is an electron-emitting device having an electron-emitting portion in a state in which the amount of positive charge and the amount of negative charge due to accumulation of electrons are balanced by applying a negative voltage (first The amount of negative charge is greater than the amount of positive charge as more electrons accumulate. The second state force changes to a state (third state) in which the amount of positive charge and the amount of negative charge associated with electron emission are balanced by applying a positive voltage. When the amount of positive charges changes to a state where the amount of positive charges is larger than the amount of negative charges as more electrons are emitted, the applied voltage for changing to the first state is set to VI and the third state. Mark for change Caro]

I VI I <I V2 I

It is characterized by having the following characteristics. In this case, 1.5 X I VI I <I V2 I may be used.

[0030] This facilitates application to a display having a plurality of electron-emitting devices arranged in accordance with a plurality of pixels and performing image display by electron emission from each electron-emitting device.

[0031] For example, when the display period of one image is one frame, all the electron-emitting devices are scanned during a certain period in the one frame to emit a plurality of electrons corresponding to the pixel to be emitted. By applying a storage voltage corresponding to the luminance level of the pixel corresponding to each element, an amount of charge corresponding to the luminance level of the pixel corresponding to each of the plurality of electron-emitting elements corresponding to the pixel to be emitted is accumulated. In the next period, a constant emission voltage is applied to all the electron-emitting devices, and the plurality of electron-emitting device forces corresponding to the pixels to be lit are each in an amount corresponding to the luminance level of the corresponding pixel. Can be emitted, and the pixel to be lit can emit light.

In this invention, the ratio of the change in the amount of positive charge and the amount of electrons in the first state is Δ Q1Z ΔVI, and the ratio of the change in the amount of positive charge and the amount of electrons in the third state (A Q1Z AV1)> (A Q2Z AV2) where Δ Q 2Z AV2 Based on these relationships, when V3 is the voltage at which electrons are accumulated and saturated, and V4 is the voltage at which electrons start to be emitted, the characteristics of 1≤I V4 I / I V3 I ≤1.5 are obtained. be able to.

[0033] Usually, for example, the electron-emitting devices are arranged in a matrix, and the electron-emitting devices are selected in units of one row in synchronization with the horizontal scanning period, and each of the selected electron-emitting devices is selected. When the pixel signal corresponding to the luminance level of the pixel is supplied, the pixel signal is also supplied to the non-selected pixel. [0034] If the electron-emitting device in the non-selected state, for example, emits electrons due to the influence of the pixel signal, there is a problem that the image quality of the display image is deteriorated and the contrast is lowered.

However, since the present invention has the characteristics described above, the voltage level of the pixel signal supplied to the electron-emitting device in the selected state is an arbitrary voltage from the reference voltage to the voltage V3, and is not selected. Even in a simple voltage relationship where, for example, a signal having a polarity opposite to that of the pixel signal is supplied to the electron-emitting device in the state, the non-selected pixel is detected by the signal to the pixel in the selected state. A memory effect can be achieved at each pixel that is not affected.

High brightness and high contrast can be achieved.

[0036] The electron-emitting device according to the present invention includes a substance serving as an emitter made of a dielectric, and a first electrode and a second electrode to which a driving voltage for electron emission is applied. In the electron-emitting device, by applying a voltage in one direction between the first electrode and the second electrode, a state force in which the substance serving as the emitter is polarized in one direction is changed to a state in which polarization is reversed. a voltage as a first coercive voltage vl, when the voltage applied to the thus the polarization of the voltage from the state in the other direction is changed in the one direction again and the second coercive voltage v2, VKO or V ² ° 0 And having the characteristics of I vl I and IV ² I. In this case, 1.5 XI vl I <I v2 I may be sufficient.

[0037] When the rate of change in polarization when the first coercive voltage is applied is A qlZ Avl, and the rate of change in polarization when the second coercive voltage is applied is A q2Z Av2, (Δql / Δν1)> (Δq2 / Δν2). From these relationships, when the voltage at which electrons are accumulated and saturated is v3, and the voltage at which electrons start to be emitted is v4, the characteristics of 1≤I v4 I / I v3 I ≤1.5 can be obtained. it can.

Therefore, also in the present invention, it is easy to apply to a display having a plurality of electron-emitting devices arranged according to a plurality of pixels and displaying an image by electron emission from each electron-emitting device. become.

Also, the memory effect can be realized in each pixel in which the non-selected pixel is not affected by the signal to the selected pixel, and high brightness and high contrast can be achieved.

[0040] As described above, according to the electron-emitting device of the present invention, high electric field concentration can be easily generated, and the force can be increased in the number of electron-emitting locations. Therefore, high output and high efficiency can be achieved, and low voltage driving (low power consumption) is also possible.

[0041] Further, according to the electron-emitting device according to the present invention, the display has a plurality of electron-emitting devices arranged in accordance with a plurality of pixels, and displays an image by electron emission of each electron-emitting device force. Easy to apply.

Brief Description of Drawings

FIG. 1 is a cross-sectional view showing a partially omitted electron-emitting device according to the first embodiment.

FIG. 2 is an enlarged cross-sectional view showing a main part of the electron-emitting device according to the first embodiment.

FIG. 3 is a plan view showing an example of the shape of a through-hole formed in the upper electrode.

FIG. 4 is a diagram showing a voltage waveform of a drive voltage in the first electron emission method.

FIG. 5 is an explanatory diagram showing the state of electron emission in the second output period of the first electron emission method.

FIG. 6 is a diagram showing a voltage waveform of a drive voltage in the second electron emission method.

FIG. 7 is an explanatory diagram showing a state of electron emission in the second output period of the second electron emission method.

FIG. 8 is a diagram showing an example of a cross-sectional shape of a collar portion of the upper electrode.

FIG. 9 is a diagram showing another example of the cross-sectional shape of the collar portion of the upper electrode.

FIG. 10 is a diagram showing still another example of the cross-sectional shape of the collar portion of the upper electrode.

FIG. 11 is an equivalent circuit diagram showing a connection state of various capacitors connected between the upper electrode and the lower electrode.

[FIG. 12] FIG. 12 is a diagram for explaining the capacitance calculation of various capacitors connected between the upper electrode and the lower electrode.

FIG. 13 is a plan view showing a first modification of the electron-emitting device according to the first embodiment with a part thereof omitted.

FIG. 14 is a plan view showing a second modification of the electron-emitting device according to the first embodiment with a part thereof omitted.

FIG. 15 is a partial omission of a third modification of the electron-emitting device according to the first embodiment. FIG.

FIG. 16 is a diagram showing the voltage-charge amount characteristic (voltage-polarization amount characteristic) of the electron-emitting device according to the first embodiment.

FIG. 17A is an explanatory diagram showing the state at point p 1 in FIG. 16, FIG. 17B is an explanatory diagram showing the state at point p 2 in FIG. 16, and FIG. 17C is from the point p 2 in FIG. It is explanatory drawing which shows the state until it reaches point p3.

[FIG. 18] FIG. 18A is an explanatory diagram showing a state from point p3 to point p4 in FIG. 16, FIG. 18B is an explanatory diagram showing a state immediately before reaching point p4 in FIG. 16, and FIG. FIG. 17 is an explanatory diagram showing a state from point p4 to point p6 in FIG.

FIG. 19 is a block diagram showing a display unit and a drive circuit of a display configured using the electron-emitting device according to the first embodiment.

FIG. 20A to FIG. 20C are waveform diagrams showing amplitude modulation of a pulse signal by the amplitude modulation circuit.

FIG. 21 is a block diagram showing a signal supply circuit according to a modification.

FIG. 22A to FIG. 22C are waveform diagrams showing pulse width modulation of a pulse signal by a pulse width modulation circuit.

FIG. 23A is a diagram showing a hysteresis curve when the voltage Vsl in FIG. 20A or FIG. 22A is applied, and FIG. 23B is a hysteresis curve when the voltage Vsm in FIG. 20B or 22B is applied. FIG. 23C is a diagram showing a hysteresis curve when the voltage Vsh in FIG. 20C or FIG. 22C is applied.

FIG. 24 is a configuration diagram showing one arrangement example of the collector electrode, the phosphor and the transparent plate on the upper electrode.

FIG. 25 is a configuration diagram showing another arrangement example of the collector electrode, the phosphor and the transparent plate on the upper electrode.

圆 26] Fig. 26A is a diagram showing the waveforms of the write pulse and the lighting pulse used in the first experimental example (experiment of the electron emission state of the electron-emitting device), and Fig. 26B shows the waveform in the first experimental example. FIG. 6 is a diagram showing a state of electron emission from the electron-emitting device with a detection voltage waveform of the light-receiving device. [FIG. 27] FIG. 27 is a diagram showing waveforms of an address pulse and a lighting pulse used in the second to fourth experimental examples.

FIG. 28 is a characteristic diagram showing the results of a second experimental example (an experiment in which the amount of electrons emitted from the electron-emitting device varies depending on the amplitude of the write pulse).

FIG. 29 is a characteristic diagram showing the results of a third experimental example (an experiment in which the amount of electrons emitted from the electron-emitting device varies depending on the amplitude of the lighting pulse).

FIG. 30 is a characteristic diagram showing the results of a fourth experimental example (an experiment in which the amount of electrons emitted from the electron-emitting device varies depending on the collector voltage level).

FIG. 31 is a timing chart showing an example of a display driving method.

FIG. 32 is a table showing a relationship between applied voltages in the driving method shown in FIG.

FIG. 33 is a cross-sectional view showing a partially omitted electron-emitting device according to the second embodiment.

FIG. 34 is a cross-sectional view showing a first modification of the electron-emitting device according to the second embodiment with a part thereof omitted.

FIG. 35 is a cross-sectional view showing a partially omitted second modification of the electron-emitting device according to the second embodiment.

FIG. 36 is a cross-sectional view showing a third variation of the electron-emitting device according to the second embodiment with a part thereof omitted.

FIG. 37 is a cross-sectional view showing the electron-emitting device according to the third embodiment with a part thereof omitted.

FIG. 38 is a cross-sectional view showing a first modification of the electron-emitting device according to the third embodiment with a part thereof omitted.

FIG. 39 is a cross-sectional view showing a partially omitted electron-emitting device according to a conventional example. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the electron-emitting device according to the present invention will be described with reference to FIGS.

[0044] First, the electron emission device according to the present embodiment is applied not only as a display, but also to an electron beam irradiation device, a light source, an LED alternative use, an electronic component manufacturing device, and an electronic circuit component. can do.

[0045] The electron beam in the electron beam irradiation apparatus has high energy and excellent absorption performance as compared with the ultraviolet light in the currently widely used ultraviolet irradiation apparatus. Examples of applications include solidifying insulating films when stacking wafers in semiconductor devices, applications that cure printing inks uniformly when printing is dried, and applications that sterilize medical devices in their packaging. There is.

[0046] The use as a light source is for high luminance and high efficiency specifications, and includes, for example, a light source application for a projector in which an ultra-high pressure mercury lamp or the like is used. When the electron-emitting device according to this embodiment is applied to a light source, it has features such as downsizing, long life, high-speed lighting, and reduced environmental load due to mercury-free.

[0047] As LED alternative applications, there are surface light source applications such as indoor lighting, automotive lamps, traffic lights, etc., chip light sources, traffic lights, backlights for small liquid crystal displays for mobile phones

[0048] Applications of the electronic component manufacturing apparatus include an electron beam source for a film forming apparatus such as an electron beam evaporation apparatus, an electron source for plasma generation (for active gases such as gas) in a plasma CVD apparatus, and gas decomposition. There are applications such as electron sources. There are also vacuum microdevice applications such as terahertz high-speed switching elements and high-current output elements. In addition, it is also preferably used as a printer component, that is, a light emitting device for exposing a photosensitive drum by a combination with a phosphor, and an electron source for charging a dielectric.

[0049] Electronic circuit components can be used for digital devices such as switches, relays, and diodes, and analog devices such as operational amplifiers because they can output a large current and have a high amplification factor.

First, as shown in FIG. 1, an electron-emitting device 10A according to the first embodiment includes a plate-like emitter part (substance serving as an emitter) 12 made of a dielectric, and the emitter part 12 A first electrode (for example, an upper electrode) 14 formed on the first surface (for example, the upper surface) of the first electrode and a second electrode (for example, the lower electrode) formed on the second surface (for example, the lower surface) of the emitter 12. 16 and a pulse generation source 18 for applying a driving voltage Va between the upper electrode 14 and the lower electrode 16.

[0051] The upper electrode 14 has a plurality of through portions 20 through which the emitter portion 12 is exposed. In particular, Emits Concavities and convexities 22 due to dielectric grain boundaries are formed on the surface of the upper portion 12, and the through-holes 20 of the upper electrode 14 are formed in portions corresponding to the recesses 24 in the grain boundaries of the dielectric. In the example of FIG. 1, the case where one through portion 20 is formed corresponding to one concave portion 24 is shown, but there may be a case where one through portion 20 is formed corresponding to a plurality of concave portions 24. . The particle size of the dielectric constituting the emitter portion 12 is preferably 0.1 m-10 m, and more preferably 2 μΐη-7 μm. In the example shown in Fig. 1, the particle size of the dielectric is 3 μm.

Further, in the first embodiment, as shown in FIG. 2, a surface 26 a of the upper electrode 14 facing the emitter portion 12 in the peripheral portion 26 of the through portion 20 is separated from the emitter portion 12. is doing. In other words, a gap 28 is formed between the surface 26 a of the upper electrode 14 facing the emitter 12 in the peripheral portion 26 of the penetrating portion 20 and the emitter portion 12, and the peripheral portion 26 of the penetrating portion 20 in the upper electrode 14. Is shaped like a bowl (flange). Therefore, in the following description, “the peripheral portion 26 of the through portion 20 of the upper electrode 14” is referred to as “the flange portion 26 of the upper electrode 14”. In the examples of FIGS. 1, 2, 5, 5, 7, 8-10, and 15, the cross section of the protrusion 30 of the irregularities 22 in the dielectric grain boundaries is typically shown in a semicircular shape. A certain force is not limited to this shape.

Further, in the first embodiment, the thickness t of the upper electrode 14 is set to 0.01 m ≦ t ≦ 10 m, and the upper surface of the emitter 12, that is, the convex portion 30 at the grain boundary of the dielectric is 30. The maximum angle Θ between the surface of the upper electrode 14 (which is also the inner wall surface of the recess 24) and the lower surface 26a of the flange 26 of the upper electrode 14 is set to 1 ° ≤ Θ ≤ 60 °. In addition, the maximum distance d along the vertical direction between the surface of the convex portion 30 (inner wall surface of the concave portion 24) and the lower surface 26a of the flange portion 26 of the upper electrode 14 at the dielectric grain boundary of the emitter 12 is expressed as follows: 0 m <d ≤ 10 m.

[0054] Further, in the first embodiment, the shape of the penetrating portion 20, in particular, as shown in FIG. 3, is the shape of the hole 32, for example, a circular shape or an elliptical shape. There are those that include a curved portion such as a track shape, and polygonal shapes such as a square and a triangle. In the example of FIG. 3, the hole 32 has a circular shape.

In this case, the average diameter of the holes 32 is 0.1 m or more and 10 m or less! This average diameter represents the average of the lengths of different line segments passing through the center of the hole 32.

[0056] Here, the material of each component will be described. As the dielectric constituting the emitter section 12, a dielectric having a relatively high relative dielectric constant, for example, 1000 or more may be employed. it can. In addition to barium titanate, such dielectrics include lead zirconate, lead magnesium niobate, lead nickel niobate, lead zinc niobate, manganese manganate lead tantalate, lead nickel tantalate, Ceramics containing lead antimony stannate, lead titanate, lead magnesium tungstate, lead cobalt niobate, etc., or any combination thereof, and those whose main component contains 50% by weight or more of these compounds In addition, lanthanum, calcium, strontium, molybdenum, tungsten, norium, niobium, zinc, nickel, manganese and other oxides, combinations of these, or other compounds are appropriately applied to the ceramics. It is possible to list those added to the above.

[0057] For example, in the binary system nPMN-mPT (where n and m are mole ratios) of lead magnesium niobate (PMN) and lead titanate (PT), increasing the mole ratio of PMN, The Curie point is lowered, and the dielectric constant at room temperature can be increased.

In particular, when n = 0.85-1.0 and m = l.0−n, the relative dielectric constant is preferably 3000 or more. For example, when n = 0.91 and m = 0.09, it is possible to obtain an it permittivity of 15000 at room temperature, and when n = 0.95 and m = 0.05, a relative permittivity of 20000 at room temperature is obtained.

[0059] Next, in the three-component system of lead magnesium niobate (PMN), lead titanate (PT), and lead zirconate (PZ), in addition to increasing the molar ratio of PMN, tetragonal and pseudocubic crystals Alternatively, a composition in the vicinity of a morphotropic phase boundary (MPB) between a tetragonal crystal and a rhombohedral crystal is preferable for increasing the relative dielectric constant. For example, PMN: PT: PZ = 0.3 75: 0. 375: 0.25 [trowel it dielectric constant 5500, PMN: PT: PZ = 0.5: 0. 375: 0.125 The rate is 4500, which is particularly preferable. Furthermore, it is preferable to improve the dielectric constant by mixing a metal such as platinum into these dielectrics within a range that can ensure insulation. In this case, for example, 20% by weight of platinum may be mixed in the dielectric.

As described above, the emitter 12 can be a piezoelectric Z electrostrictive layer, an antiferroelectric layer, or the like. When the piezoelectric Z electrostrictive layer is used as the emitter 12, the piezoelectric Z Examples of electrostrictive layers include lead zirconate, lead magnesium niobate, lead nickel niobate, lead zinc niobate, lead manganese niobate, lead magnesium tantalate, lead nickel tantalate, antimony stannate, titanium Acid bell, barium titanate, magnesium tungstic acid bell , Cobalt niobate bell, etc., or ceramics containing any combination thereof.

[0061] Principal component strength S The compound may contain 50% by weight or more of these compounds. Among the ceramics, a ceramic containing lead zirconate is most frequently used as a constituent material of the piezoelectric Z electrostrictive layer constituting the emitter section 12.

[0062] When the piezoelectric Z electrostrictive layer is composed of ceramics, the ceramics may further include oxides such as lanthanum, calcium, strontium, molybdenum, tungsten, norium, niobium, zinc, nickel, manganese, Alternatively, a ceramic obtained by appropriately adding any combination of these or other compounds may be used. In addition, ceramics with Si O, CeO, Pb Ge O or any combination thereof added to the ceramics.

2 2 5 3 11

May be used. Specifically, 0.2 wt% of SiO is added to PT-PZ-PMN piezoelectric material.

2

A material containing 0.1 wt% CeO or 1 to 2 wt% Pb Ge 2 O is preferred.

2 5 3 11

[0063] For example, it is preferable to use a ceramic containing lead magnesium niobate, lead zirconate and lead titanate as main components and further containing lanthanum or strontium.

[0064] When the piezoelectric Z electrostrictive layer is dense or porous, the porosity is preferably 40% or less.

[0065] When an antiferroelectric layer is used as the emitter section 12, the antiferroelectric layer is mainly composed of lead zirconate as a main component, or a component composed of lead zirconate and lead stannate. However, it is desirable to add a lanthanum acid zirconate to a zirconate bell and add zirconate or lead niobate to a component that has the power of a zirconate bell and a tin stannate.

[0066] Further, the antiferroelectric layer may be porous, and in the case of being porous, the porosity is preferably 30% or less.

[0067] Further, strontium bismuth tantalate (SrBi Ta 2 O 3) was used for the emitter 12.

In the case of 2 2 9, polarization inversion fatigue is small and preferable. Such a material with low polarization reversal fatigue is a layered ferroelectric compound and is represented by the general formula (BiO ² ) ² ⁺ (ABO ² ) ² . Where gold

2 m-1 m 3m + l

The ions of genus A are Ca ²⁺ , Sr ²⁺ , Ba Pb ²⁺ , Bi ³⁺ , La ³⁺ etc., and the ions of metal B are Ti ⁴⁺ , Ta ⁵⁺ , Nb ⁵⁺ etc. . [0068] Further, by mixing a piezoelectric Z electrostrictive Z antiferroelectric ceramic with a glass component such as lead borosilicate glass and other low melting point compounds (for example, bismuth oxide), the firing temperature is reduced. Can be lowered.

[0069] Further, in the case of being composed of piezoelectric Z electrostrictive Z antiferroelectric ceramics, the shape thereof is a sheet-like molded body, a sheet-like laminated body, or those obtained by laminating or bonding these to another supporting substrate. It may be.

[0070] In addition, by using a lead-free material for the emitter 12 and making the emitter 12 a material having a high melting point or high evaporation temperature, it becomes difficult to be damaged by the collision of electrons or ions. .

[0071] The upper electrode 14 is made of an organometallic paste that provides a thin film after firing. For example, a material such as platinum resinate paste is preferably used. Also, oxide electrodes that suppress polarization reversal fatigue such as ruthenium oxide (RuO), iridium oxide (IrO), ruthenium

2 2 Strontium teniumate (SrRuO), La Sr CoO (eg χ = 0 · 3 or 0 · 5), La

3 1-χ χ 3 1-χ

Ca ΜηΟ (if row f, χ = 0.2), La Ca Mn Co O (row f, row x = 0.2, y = 0.05), x 3 1-x x 1-y y 3

For example, a mixture of these in platinum resinate paste is preferable.

[0072] The upper electrode 14 is made of the above-mentioned materials using various thick film forming methods such as screen printing, spraying, coating, dubbing, coating, and electrophoresis, sputtering, ion beam, and vacuum deposition. , Ion plating, chemical vapor deposition (CVD), and various other thin film formation methods such as plating, can be formed according to a normal film formation method, preferably the former thick film formation method .

On the other hand, the lower electrode 16 is made of platinum, molybdenum, tungsten, or the like. Further, it is composed of a conductor having resistance to a high-temperature oxidizing atmosphere, such as a simple metal, an alloy, a mixture of an insulating ceramic and a simple metal, a mixture of an insulating ceramic and an alloy, and preferably, platinum, iridium High melting point precious metals such as palladium, rhodium, molybdenum, etc., and those composed mainly of alloys such as silver-palladium, silver-platinum, platinum-palladium, and cermet materials of platinum and ceramic materials. More preferably, it is made of a material mainly composed of platinum or a platinum-based alloy.

[0074] Further, the lower electrode 16 may be made of carbon or a graphite-based material. Electricity The ratio of the ceramic material added to the pole material is preferably about 5-30% by volume. Of course, you may use the same material as the upper electrode mentioned above.

The lower electrode 16 is preferably formed by the thick film forming method. The thickness of the lower electrode 16 is preferably 20 m or less, more preferably 5 m or less.

[0076] A heat treatment (firing treatment) is performed each time the emitter 12, the upper electrode 14, and the lower electrode 16 are formed, whereby an integrated structure can be obtained.

[0077] The temperature involved in the firing process for integrating the emitter section 12, the upper electrode 14, and the lower electrode 16 is in the range of 500-1400 ° C, preferably in the range of 1000-1400 ° C. Good. Furthermore, when heat-treating the film-like emitter 12, it is preferable to perform a firing process while controlling the atmosphere together with the evaporation source of the emitter 12 so that the composition of the emitter 12 is not unstable at high temperatures. .

By performing the firing treatment, in particular, the film to be the upper electrode 14 contracts, for example, from a thickness of 10 m to a thickness of 0.0: m, and at the same time, a plurality of holes and the like are formed. As a result, FIG. As shown, a plurality of through portions 20 are formed in the upper electrode 14, and a peripheral portion 26 of the through portion 20 is formed in a bowl shape. Of course, the film to be the upper electrode 14 may be baked after being patterned (wet etching or dry etching) or lift-off or the like in advance (before baking). In this case, as will be described later, a notch shape or a slit shape can be easily formed as the through portion 20.

[0079] Note that a method may be employed in which the emitter portion 12 is covered with an appropriate member and the surface of the emitter portion 12 is not directly exposed to the firing atmosphere.

Next, the principle of electron emission of the electron emitter 10A will be described. First, a drive voltage Va is applied between the upper electrode 14 and the lower electrode 16. This drive voltage Va is higher or lower than the reference voltage (e.g. OV) from the reference voltage (e.g. OV) or lower than the reference voltage over time, such as a Norse voltage or an AC voltage. High !, defined as a voltage that rapidly changes to the voltage level.

[0081] Further, a triple junction is formed at a contact point between the upper surface of the emitter section 12, the upper electrode 14, and a medium (for example, vacuum) around the electron-emitting device 10A. Here, the triple junction is formed by contacting the upper electrode 14, the emitter 12 and the vacuum. Defined as the electric field concentration part. The triple junction includes a triple point where the upper electrode 14, the emitter 12 and the vacuum exist as one point. The degree of vacuum in the atmosphere is preferably 10 ² − 10− ⁶ Pa, more preferably 10 ³ − 10− ⁵ Pa.

In the first embodiment, the triple junction is formed at the flange portion 26 of the upper electrode 14 and the peripheral portion of the upper electrode 14. Therefore, when the drive voltage Va as described above is applied between the upper electrode 14 and the lower electrode 16, electric field concentration occurs in the triple junction described above.

First, the first electron emission method will be described with reference to FIG. 4 and FIG. In the first output period T1 in FIG. 4, a voltage V2 lower than the reference voltage (in this case, OV) is applied to the upper electrode 14, and a voltage VI higher than the reference voltage is applied to the lower electrode 16. In the first output period T1, electric field concentration occurs in the triple junction described above.For example, in the emitter part 12, the part exposed from the through part 20 of the upper electrode 14 or the part near the peripheral part of the upper electrode 14 is used. Electrons are accumulated. At this time, the upper electrode 14 functions as an electron supply source.

[0084] In the next second output period T2, the voltage level of the driving voltage Va changes rapidly, that is, a voltage VI higher than the reference voltage is applied to the upper electrode 14, and the reference voltage is applied to the lower electrode 16. When a voltage V2 lower than the voltage is applied, the electric field concentration in the reverse direction occurs at the triple junction described above, and the electrons are accumulated in the emitter section 12 as shown in FIG. Electrons are emitted from the exposed portion through the penetrating portion 20. Of course, electrons near the outer periphery of the upper electrode 14 are also emitted.

Next, the second electron emission method will be described. First, in the first output period T1 in FIG. 6, a voltage V3 higher than the reference voltage is applied to the upper electrode 14, and a voltage V4 lower than the reference voltage is applied to the lower electrode 16. In the first output period T1, preparation for electron emission (for example, polarization in one direction of the emitter 12) is performed. In the next second output period T2, the voltage level of the drive voltage Va changes suddenly, that is, a voltage V4 lower than the reference voltage is applied to the upper electrode 14, and a voltage V3 higher than the reference voltage is applied to the lower electrode 16. When applied, this time, an electric field concentration occurs in the above-described triple junction, and the primary electrons are emitted from the upper electrode 14 due to the electric field concentration. It will collide with the part exposed from the penetration part 20, and the outer peripheral part vicinity of the upper electrode 14. FIG. As a result, as shown in FIG. 7, secondary electrons (including reflected electrons of the primary electrons) are emitted from the portion where the primary electrons collide. That is, in the initial stage of the second output period T2, secondary electrons are emitted from the vicinity of the outer peripheral portion of the penetrating portion 20 and the upper electrode 14.

Then, in the electron-emitting device 10A according to the first embodiment, since the plurality of through portions 20 are formed in the upper electrode 14, each of the through portions 20 and the peripheral force near the outer peripheral portion of the upper electrode 14 are formed. Electrons are emitted evenly, the variation in the overall electron emission characteristics is reduced, the electron emission is easily controlled, and the electron emission efficiency is increased.

[0087] In the first embodiment, since the gap 28 is formed between the flange portion 26 and the emitter portion 12 of the upper electrode 14, when the drive voltage Va is applied, Electric field concentration is likely to occur in the gap 28 portion. This leads to a high efficiency of electron emission, and a low driving voltage (electron emission at a low voltage level) can be realized.

[0088] As described above, in the first embodiment, the upper electrode 14 has the flange portion 26 formed in the peripheral portion of the penetrating portion 20, and thus the electric field concentration in the gap 28 portion described above. Combined with the increase in size, electrons are easily emitted from the flange 26 of the upper electrode 14. This leads to higher output and higher efficiency of electron emission, and lowering of the drive voltage Va can be realized. In addition, the first electron emission method (the method for emitting electrons accumulated in the emitter unit 12) and the second electron emission method (the primary electrons from the upper electrode 14 collide with the emitter unit 12). Even if the secondary electron is emitted, the flange 26 of the upper electrode 14 functions as a gate electrode (control electrode, focus electron lens, etc.), so that the straightness of the emitted electrons can be improved. Can do. This is advantageous in reducing crosstalk when a large number of electron-emitting devices 10A are arranged to form, for example, an electron source for a display.

As described above, in the electron-emitting device 10A according to the first embodiment, high electric field concentration can be easily generated, the force can be increased, and the number of electron emission locations can be increased. High output and high efficiency can be achieved, and low voltage drive (low power consumption) is also possible.

[0090] In particular, in the first embodiment, at least the upper surface of the emitter section 12 is caused by a dielectric grain boundary. The upper electrode 14 has a through-hole 20 formed in a portion corresponding to the recess 24 in the grain boundary of the dielectric, so that the flange 26 of the upper electrode 14 can be easily realized. Can be made.

[0091] Further, the upper surface of the emitter 12, that is, the maximum angle formed by the surface of the convex portion 30 (inner wall surface of the concave portion 24) at the grain boundary of the dielectric and the lower surface 26a of the flange portion 26 of the upper electrode 14 0 is set to 1 ° ≤ Θ ≤ 60 °. Between the surface of the convex part 30 (the inner wall surface of the concave part 24) and the lower surface 26a of the flange part 26 of the upper electrode 14 at the grain boundary of the dielectric of the emitter part 12 Since the maximum distance d along the vertical direction is Ο μ m <d ≤ 10 μ m, these configurations can increase the degree of electric field concentration at the gap 28 and High output, high efficiency, and low drive voltage can be efficiently achieved.

Further, in the first embodiment, the through portion 20 has the shape of the hole 32. As shown in FIG. 2, the portion of the emitter 12 where the polarization is reversed or changed according to the driving voltage Va applied between the upper electrode 14 and the lower electrode 16 (see FIG. 1) Formed V, a part immediately below the first part (first part) 40, and a part (second part) 42 corresponding to a region from the inner periphery of the penetrating part 20 toward the inner part of the penetrating part 20, The second portion 42 changes depending on the level of the driving voltage Va and the degree of electric field concentration. Therefore, in the first embodiment, the average diameter of the holes 32 is set to 0.1 m or more and 10 μm or less. Within this range, there is almost no variation in the emission distribution of electrons emitted through the penetrating portion 20, and electrons can be emitted efficiently.

[0093] When the average diameter of the holes 32 is less than 0.1 µm, the region for accumulating electrons is narrowed, and the amount of electrons emitted is reduced. Of course, it is conceivable to provide a large number of holes 32, but there is a concern that the manufacturing cost will increase due to difficulty. When the average diameter of the holes 32 exceeds 10 m, the ratio (occupancy) of the portion (second portion) 42 contributing to electron emission in the portion exposed from the penetrating portion 20 of the emitter 12 is small. Thus, the electron emission efficiency is reduced.

As shown in FIG. 2, the cross-sectional shape of the flange portion 26 of the upper electrode 14 may be a shape that extends horizontally on both the upper surface and the lower surface, and as shown in FIG. It is almost horizontal, and the upper end of the collar 26 may be raised upward. Further, as shown in FIG. 9, the lower surface 26a of the flange portion 26 gradually inclines upward toward the center of the penetrating portion 20. Alternatively, as shown in FIG. 10, the lower surface 26a of the flange portion 26 may be gradually inclined downward toward the center of the penetrating portion 20. The example of FIG. 8 can enhance the function as a gate electrode. In the example of FIG. 10, the gap 28 is narrowed, so that electric field concentration is more likely to occur, and high output of electron emission, High efficiency can be improved.

In the first embodiment, as shown in FIG. 11, in the electrical operation, the capacitor C 1 by the emitter unit 12 and the gaps 28 are interposed between the upper electrode 14 and the lower electrode 16. A plurality of capacitor Ca aggregates are formed. That is, a plurality of capacitors Ca by each gear 28 are configured as one capacitor C2 connected in parallel to each other, and in terms of equivalent circuit, a capacitor C1 by the emitter 12 is connected in series with the capacitor C2 by the aggregate. It becomes a connected form.

[0096] Actually, the capacitor C1 by the emitter 12 is not connected in series to the capacitor C2 by the aggregate, depending on the number of through-holes 20 formed in the upper electrode 14, the overall formation area, etc. The capacitor component connected in series changes.

Here, as shown in FIG. 12, for example, the capacitance calculation is performed assuming that 25% of the capacitor C1 by the emitter 12 is connected in series with the capacitor C2 by the aggregate. . First, since the gap 28 is vacuum, the relative dielectric constant is 1. The maximum interval d of the gaps 28 is 0.1 m, the area S of one gap 28 is S = 1 ^ mxl / zm, and the number of gaps 28 is 10,000. Also, assuming that the dielectric constant of the emitter 12 is 2000, the thickness of the emitter 12 is 20 m, and the opposing area of the upper electrode 14 and the lower electrode 16 is 200 m X 200 μm, the capacitance value of the capacitor C2 by the aggregate Is 0.885pF, and the capacitance value of the capacitor C1 by the emitter section 12 is 35.4pF. When the portion connected in series with the capacitor C2 by the aggregate in the capacitor C1 by the emitter 12 is 25% of the total, the capacitance value of the capacitor connected by the series (capacitance of the capacitor C2 by the aggregate) The capacitance value including the quantity value is 0.805 pF, and the remaining capacitance value is 26.6 pF.

[0098] Since the serially connected portion and the remaining portion are connected in parallel, the total capacitance value is 27.5 pF. This capacitance value is 78% of the capacitance value 35.4pF of the capacitor C1 by the emitter 12. That is, the total capacitance value is less than the capacitance value of the capacitor C1 by the emitter unit 12 / J. [0099] As described above, the aggregate of the capacitors Ca by the plurality of gaps 28 has a relatively small capacitance value of the capacitor Ca by the gaps 28. From the partial pressure with the capacitor C1 by the emitter unit 12, Most of the applied voltage Va is applied to the gap 28, and in each gap 28, high output of electron emission is realized.

[0100] Further, since the capacitor C2 by the aggregate has a structure connected in series to the capacitor C1 by the emitter section 12, the overall capacitance value is smaller than the capacitance value of the capacitor C1 by the emitter section 12. For this reason, the electron emission has a high output, and if the overall power consumption becomes small, it is preferable to obtain characteristics.

Next, three modifications of the electron-emitting device 10A according to the first embodiment described above will be described with reference to FIGS.

First, the electron-emitting device lOAa according to the first modification differs as shown in FIG. 13 in that the shape of the penetrating portion 20, particularly the shape in view of the upper surface force, is the shape of the notch 44. As the shape of the notch 44, as shown in FIG. 13, a comb-like notch 46 in which a large number of notches 44 are continuously formed is preferable. In this case, the variation in the emission distribution of the electrons emitted through the through-hole 20 is reduced, which is advantageous in efficiently emitting electrons. In particular, it is preferable that the average width of the notches 44 is not less than 0 and not more than 10 m. This average width indicates the average of the lengths of a plurality of different line segments orthogonal to the center line of the notch 44.

As shown in FIG. 14, the electron-emitting device lOAb according to the second modification is different in that the shape of the penetrating portion 20, particularly the shape seen from the top surface, is a slit 48. Here, the slit 48 is a slit having a length in the major axis direction (longitudinal direction) of 10 or more times the length in the minor axis direction (short direction). Therefore, a hole having a length in the major axis direction (longitudinal direction) less than 10 times the length in the minor axis direction (short direction) can be defined as the shape of the hole 32 (see FIG. 3). Further, the slit 48 includes one in which a plurality of holes 32 are connected and connected. In this case, the average width of the slits 48 is preferably set to 0 .: m or more and 10 m or less. This is because variations in the emission distribution of electrons emitted through the penetrating portion 20 are reduced, and this is advantageous in efficiently emitting electrons. This average width indicates the average length of a plurality of different line segments orthogonal to the center line of the slit 48.

[0104] The electron-emitting device lOAc according to the third modification is formed on the top of the emitter 12 as shown in FIG. The difference is that the floating electrode 50 exists in a portion of the surface corresponding to the penetrating portion 20, for example, the concave portion 24 of the grain boundary of the dielectric. In this case, since the floating electrode 50 also serves as an electron supply source, in the electron emission stage (the second output period T2 in the first electron emission method described above (see FIG. 4)), a large number of electrons are passed through the through-hole. It can be released outside through 20.

Here, characteristics of the electron-emitting device 10A according to the first embodiment, in particular, voltage charge amount characteristics (voltage-polarization amount characteristics) will be described.

The electron-emitting device 10A according to the first embodiment draws an asymmetric hysteresis curve with reference voltage = o (v) as a reference, as shown in the characteristics of FIG. 16, in vacuum.

[0107] This characteristic will be described. First, when the electron emitting portion of the emitter 12 is defined as an electron emitting portion, at the point pi (initial state) where a reference voltage is applied, the electron emitting portion In this state, almost no electrons are accumulated. Thereafter, when a negative voltage is applied, the amount of positive charges in the electron emission portion increases, and accordingly, electrons are accumulated. As the level of the negative voltage is increased in the negative direction, the amount of positive charge and the amount of electrons are balanced at a certain negative voltage point p2 as the electrons accumulate in the electron emission portion, and the negative voltage Increasing the level in the negative direction further increases the amount of accumulated electrons, resulting in a state where the amount of negative charge is greater than the amount of positive charge. At point p3, the electron is saturated.

[0108] Thereafter, when the level of the negative voltage is decreased and a positive voltage is applied exceeding the reference voltage, emission of electrons starts at point p4. Increasing this positive voltage in the positive direction increases the amount of emitted electrons, and at point p5, the amount of positive charge and the amount of electrons are balanced. At the point _P 6, the accumulated electrons are almost released, and the difference between the positive charge amount and the negative charge amount is almost the same as in the initial state.

[0109] Characteristic portions of this characteristic are as follows.

[0110] (1) When the negative voltage at point p2 where the amount of positive charge and the amount of electrons are in equilibrium is VI, and the positive voltage at point p5 is V2,

I VI I <I V2 I

It is. [0111] (2) More specifically, 1.5 XI VI I <I V2 I.

[0112] (3) When the rate of change in the amount of positive charge and the amount of electrons at point p2 is A Q1Z AV1, and the rate of change in the amount of positive charge and the amount of electrons at point ρ5 is A Q2Z AV2,

(A Ql / AVl)> (A Q2 / AV2)

It is.

[0113] (4) When V3 is the voltage at which electrons are accumulated and saturated, and V4 is the voltage at which electron emission starts,

1≤ I V4 I / I V3 I ≤1.5

It is.

Next, the characteristic of FIG. 16 will be described from the standpoint of the voltage-one-polarization characteristic. In the initial state, the description will be made on the assumption that the emitter section 12 is polarized in the negative direction and the negative pole of the dipole moment is directed to the upper surface of the emitter section 12 (see FIG. 17A).

First, as shown in FIG. 16, at a point pi (initial state) where a reference voltage (eg, OV) is applied, the negative pole of the dipole moment is applied to the upper surface of the emitter section 12 as shown in FIG. 17A. Since it is in the facing state, almost no electrons are accumulated on the upper surface of the emitter 12.

[0116] After that, when a negative voltage is applied and the level of the negative voltage is increased in the negative direction, the polarization starts to reverse around the point where the negative coercive voltage is exceeded (see point p2 in Fig. 16). All polarizations are reversed at 16 points p3 (see Fig. 17B). Due to this polarization inversion, electric field concentration occurs in the triple junction described above, and electrons are accumulated in, for example, the portion exposed from the penetrating portion 20 of the upper electrode 14 or the portion near the peripheral edge of the upper electrode 14 in the emitter portion 12. (See Figure 17C). In particular, electrons are emitted (internally emitted) from the upper electrode 14 toward a portion of the emitter portion 12 exposed from the through portion 20 of the upper electrode 14. Then, at point p3 in FIG.

[0117] After that, when the level of the negative voltage is decreased and a positive voltage is applied exceeding the reference voltage, the charged state of the upper surface of the emitter unit 12 is maintained up to a certain voltage level ( (See Figure 18A). When the level of the positive voltage is further increased, a region in which the negative pole of the dipole moment begins to face the upper surface of the emitter 12 immediately before the point p4 in FIG. 16 (FIG. 18). B (see Fig. 18C), and then the level is raised and electron emission starts after point p4 in Fig. 16 (see Fig. 18C). When the positive voltage is increased in the positive direction, the amount of emitted electrons is increased, positive per exceeding the coercive voltage (the point p5) force polarization is expanded region again inverted, the point _P 6, is accumulated Most of the electrons were released, and the amount of polarization at this time was almost the same as the amount of polarization in the initial state.

[0118] Characteristic portions of the characteristics of the electron-emitting device 10A are as follows.

[0119] (A) When the negative coercive voltage is vl and the positive coercive voltage is v2,

I vl I <I v2 I

It is.

[0120] (B) More specifically, 1.5 X I vl I <I v2 I.

(C) When the rate of change in polarization when a negative coercive voltage vl is applied is A qlZ Avl, and the rate of change in polarization when a positive coercive voltage v2 is applied is Δ q2Z Δ v2,

(A ql / Avl)> (A q2 / Av2)

It is.

[0122] (D) When the voltage at which electrons are accumulated and saturated is v3 and the voltage at which electrons start to be emitted is v4,

1≤ I v4 I / I v3 I ≤1.5

It is.

[0123] Since the electron-emitting device 10A according to the first embodiment has the characteristics as described above, the electron-emitting device 10A includes a plurality of electron-emitting devices 10A arranged according to a plurality of pixels, It can be easily applied to a display that displays an image by emitting electrons from the child 10A.

Next, a display 100 configured using the electron-emitting device 10A according to the first embodiment will be described.

As shown in FIG. 19, the display 100 includes a display unit 102 in which a large number of electron-emitting devices 10A are arranged in a matrix or staggered manner corresponding to pixels, and a drive for driving the display unit 102. And a driving circuit 104. In this case, one electron emitting element 10A may be allocated per pixel, or a plurality of electron emitting elements 10A may be allocated per pixel. You may do it. In this embodiment, in order to simplify the description, the description will be made on the assumption that one electron-emitting device 10A is assigned per pixel.

This drive circuit 104 is provided with a plurality of row selection lines 106 for selecting a row for the display unit 102, and a plurality of signals for supplying the pixel signal Sd to the display unit 102. Wire 108 is wired.

In addition, the drive circuit 104 selectively supplies a selection signal Ss to the row selection line 106 to sequentially select the electron-emitting devices 10A for each row, and the signal line 108 has a parameter. The pixel signal Sd is output to the real signal, the signal supply circuit 112 supplies the pixel signal Sd to each row selected by the row selection circuit 110 (selected row), and the input video signal Sv and the synchronization signal Sc. And a signal control circuit 114 for controlling the row selection circuit 110 and the signal supply circuit 112 based on the above.

[0128] A power supply circuit 116 (for example, 50V and 0V) is connected to the row selection circuit 110 and the signal supply circuit 112, and in particular, a pulse power supply is connected between the negative line between the row selection circuit 110 and the power supply circuit 116 and GND (ground). 118 is connected. The pulse power supply 118 outputs a pulsed voltage waveform having a reference voltage (for example, 0 V) in a charge accumulation period Td, which will be described later, and a voltage (for example, 400 V) in the light emission period Th.

[0129] In the charge accumulation period Td, the row selection circuit 110 outputs the selection signal Ss to the selected row and outputs the non-selection signal Sn to the non-selected row. In addition, the row selection circuit 110 outputs a constant voltage (for example, −350 V) in which the power supply voltage (for example, 50 V) from the power circuit 116 and the voltage from the pulse power supply 118 (for example, −400 V) are added during the light emission period Th. .

The signal supply circuit 112 includes a pulse generation circuit 120 and an amplitude modulation circuit 122. The pulse generation circuit 120 generates and outputs a pulse signal Sp having a constant amplitude (eg, 50 V) with a constant pulse period during the charge accumulation period Td, and outputs a reference voltage (eg, 0 V) during the light emission period Th. To do.

[0131] In the charge accumulation period Td, the amplitude modulation circuit 122 amplitude-modulates the pulse signal Sp from the pulse generation circuit 120 in accordance with the luminance level of the pixel related to the selected row, and each pixel related to the selected row. The pixel signal Sd is output and the reference voltage from the pulse generation circuit 120 is output as it is during the light emission period Th. These timing control sequences The luminance levels of the plurality of pixels selected in the above are supplied to the amplitude modulation circuit 122 through the signal control circuit 114.

[0132] For example, as shown in three examples in FIGS. 20A to 20C, when the luminance level is low, the amplitude of the pulse signal Sp is set to the low level Vsl (see FIG. 20A), and when the luminance level is medium, The amplitude of the pulse signal Sp is set to the medium level Vsm (see Fig. 20B). If the luminance level is high, the amplitude of the pulse signal Sp is set to the high level Vsh (see Fig. 20C). In this example, when applied to the force display 100 shown in the example divided into three, the pulse signal Sp is amplitude-modulated in 128 steps or 256 steps, for example, according to the luminance level of the pixel.

Here, a modification of the signal supply circuit 112 will be described with reference to FIGS. 21 to 22C.

As shown in FIG. 21, the signal supply circuit 112a according to the modification includes a pulse generation circuit 124 and a pulse width modulation circuit 126. The pulse generation circuit 124 is a pulse whose voltage rises continuously in the voltage waveform applied to the electron emitter 10A (shown by the solid line in FIGS. 22A to 22C) during the charge accumulation period Td. Generates and outputs the signal Spa (indicated by a broken line in FIGS. 22A to 22C), and outputs a reference voltage during the light emission period Th. In the charge accumulation period Td, the pulse width modulation circuit 126 modulates the pulse width Wp (see FIGS. 22A to 22C) of the pulse signal Spa from the pulse generation circuit 124 according to the luminance level of the pixel relating to the selected row. These are output as pixel signals Sd of the pixels related to the selected row. In the light emission period Th, the reference voltage from the pulse generation circuit 124 is output as it is. Also in this case, the timing control and the supply of the luminance levels of the selected pixels to the pulse width modulation circuit 126 are performed through the signal control circuit 114.

[0135] For example, as shown in three examples in FIGS. 22A to 22C, when the luminance level is low, the pulse width Wp of the pulse signal Spa is shortened and the substantial amplitude is set to the low level Vsl (see FIG. 22A). If the brightness level is medium, the pulse width Wp of the pulse signal Spa is set to the medium length, the actual amplitude is set to the medium level Vsm (see Figure 22B), and the brightness level is high. In this case, the pulse width Wp of the pulse signal Spa is lengthened and the substantial amplitude is set to the high level Vsh (see Fig. 22C). Here are three examples, but when applied to the display 100 The pulse width of the noise signal Spa is modulated in 128 steps or 256 steps, for example, according to the luminance level of the pixel.

Here, changes in the characteristic diagram when the level of the negative voltage related to the above-described electron accumulation is changed are shown in FIG. 20A to FIG. 20C as examples of three amplitude modulations for the pulse signal Sp shown in FIG. 2A—In relation to the three pulse width modulation examples for the pulse signal Spa shown in FIG. 22C, at the negative voltage level Vsl shown in FIG. 20A and FIG. 22A, as shown in FIG. The amount of electrons stored in 10A is small. At the negative voltage level Vsm shown in FIG. 20B and FIG. 22B, the amount of accumulated electrons is medium as shown in FIG. 23B, and at the negative voltage level Vsh shown in FIG. 20C and FIG. As shown, the amount of accumulated electrons is large and almost saturated.

As shown in FIGS. 23A to 23C, the voltage level at the point p4 at which the electron emission starts is almost the same. In other words, even after the electrons are accumulated, even if the applied voltage changes up to the voltage level shown at point p4, it can be seen that a memory effect is exhibited in which there is almost no change in the amount of accumulated electrons.

[0138] When the electron-emitting device 10A according to the first embodiment is used as a pixel of the display 100, as shown in FIG. 24, a transparent material made of glass or attal, for example, is disposed above the upper electrode 14. A plate 130 is disposed, and a collector electrode 132 made of, for example, a transparent electrode is disposed on the back surface (the surface facing the upper electrode 14) of the transparent plate 130, and a phosphor 134 is applied to the collector electrode 132. . A bias voltage source 136 (collector voltage Vc) is connected to the collector electrode 132 via a resistor. Needless to say, the electron-emitting device 10A is disposed in the vacuum space. The degree of vacuum in the atmosphere is preferably 10 ² − 10− ⁶ Pa, more preferably 10 ³ − 10− ⁵ Pa.

[0139] The reason for selecting such a range is that, in a low vacuum, (1) because there are many gas molecules in the space, if too much plasma that is easy to generate plasma is generated, the amount of positive ions will be large. There is a possibility of colliding with the upper electrode 14 to promote damage, and (2) phosphors due to electrons accelerated sufficiently by the collector voltage Vc when the emitted electrons collide with gas molecules before reaching the collector electrode 132 〖. This is because 134 may not be sufficiently excited.

[0140] On the other hand, in a high vacuum, although it is easy to emit electrons from the point where the electric field concentrates, This is because there is a problem that the size of the support and the vacuum seal becomes large, which is disadvantageous for miniaturization.

In the example of FIG. 24, the collector electrode 132 is formed on the back surface of the transparent plate 130, and the phosphor 134 is formed on the surface of the collector electrode 132 (the surface facing the upper electrode 14). In addition, as shown in FIG. 25, the phosphor 134 may be formed on the back surface of the transparent plate 130, and the collector electrode 132 may be formed so as to cover the phosphor 134!

[0142] This is a configuration used in a CRT or the like, and the collector electrode 132 functions as a metal back. Electrons emitted from the emitter 12 pass through the collector electrode 132 and enter the phosphor 134 to excite the phosphor 134. Therefore, the collector electrode 132 is thick enough to allow electrons to pass through, and is preferably less than lOOnm. The greater the kinetic energy of electrons, the thicker the collector electrode 132 can be made.

[0143] With such a configuration, the following effects can be obtained.

(A) When the phosphor 134 is not conductive, charging (negative) of the phosphor 134 can be prevented, and the acceleration electric field of electrons can be maintained.

(B) The collector electrode 132 reflects the light emission of the phosphor 134, and the light emission of the phosphor 134 can be efficiently emitted to the transparent plate 130 side (light emission surface side).

(C) Excessive collision of electrons with the phosphor 134 can be prevented, and deterioration of the phosphor 134 and generation of gas from the phosphor 134 can be prevented.

Next, four experimental examples (first to fourth experimental examples) for the electron-emitting device 10A according to the first embodiment are shown.

[0148] In the first experimental example, the electron emission state of the electron-emitting device 10A is observed. That is, as shown in FIG. 26A, a write pulse Pw having a voltage of 70V is applied to the electron-emitting device 10A to accumulate electrons in the electron-emitting device 10A, and then a lighting pulse having a voltage of 280V. Ph was applied to emit electrons. The electron emission state was measured by detecting the light emission of the phosphor 1 34 with a light receiving element (photodiode). The detected waveform is shown in Figure 26B. The duty ratio of the write pulse Pw and the lighting pulse Ph was 50%.

[0149] From this first experimental example, it can be seen that light emission started in the middle of the rise of the lighting pulse Ph, and light emission ended at the initial stage of the lighting pulse Ph. Therefore, the lighting pulse Ph It is considered that the light emission is not affected even if the period is shortened. This leads to a shortening of the high voltage application period, which is advantageous in reducing the power consumption.

[0150] The second experiment example shows how the electron emission amount force of the electron-emitting device 10A changes depending on the amplitude of the write pulse Pw shown in FIG. The change in the amount of emitted electrons was measured by detecting the light emission of the phosphor 134 with a light receiving element (photodiode) as in the first experimental example. The experimental results are shown in FIG.

[0151] In Fig. 28, the solid line A shows the characteristics when the amplitude of the lighting pulse Ph is 200V and the amplitude of the writing pulse Pw is changed from 10V to 80V, and the solid line B shows the amplitude of the lighting pulse Ph is 350V. The characteristics when the amplitude of the write pulse Pw is changed from 10V to –80V are shown.

As shown in FIG. 28, when the write pulse Pw is changed from 20 V to 40 V, it can be seen that the light emission luminance changes almost linearly. In particular, when the lighting pulse Ph amplitude is 350 V and 200 V, the dynamic range of the emission luminance change with respect to the write pulse Pw is wider in the case of 350 V, which improves the brightness and contrast of the image display. It can be seen that it is advantageous for improvement. This tendency can be seen in the range until the light emission brightness is saturated with respect to the amplitude setting of the lighting pulse Ph. Therefore, it is preferable to set the optimal value.

[0153] The third experiment example shows how the electron emission amount force of the electron-emitting device 10A changes depending on the amplitude of the lighting pulse Ph shown in Fig. 27. The change in the amount of emitted electrons was measured by detecting the light emission of the phosphor 134 with a light receiving element (photodiode) as in the first experimental example. The experimental results are shown in Fig. 29.

In FIG. 29, the solid line C shows the characteristics when the amplitude of the write pulse Pw is 40V and the amplitude of the lighting pulse Ph is changed from 50V to 400V, and the solid line D is the amplitude of the write pulse Pw. Shows the characteristics when the lighting pulse Ph amplitude is changed from 50V to 400V.

As shown in FIG. 29, when the lighting pulse Ph is changed from 100 V to 300 V, it can be seen that the emission luminance changes almost linearly. In particular, write pulse Pw oscillation Comparing the width between 40V and 70V, the 70V range has a wider dynamic range of the light emission luminance change with respect to the lighting pulse Ph, which is advantageous for improving the brightness and contrast of the image display. I know that there is. This tendency is a force that seems to be more advantageous as the amplitude (in this case, absolute value) of the write pulse Pw is increased over the range until the emission luminance is saturated with respect to the amplitude setting of the write pulse Pw. Even in this case, it is preferable to set the optimum value in relation to the withstand voltage and power consumption of the signal transmission system.

[0156] The fourth experimental example looks at how the electron emission amount force of the electron-emitting device 10A changes depending on the level of the collector voltage Vc shown in Fig. 24 or Fig. 25. The change in the amount of emitted electrons was measured by detecting the light emission of the phosphor 134 with a light receiving element (photodiode) as in the first experimental example. The experimental results are shown in FIG.

[0157] In Fig. 30, the solid line E shows the characteristics when the level of the collector voltage Vc is 3kV and the amplitude of the lighting pulse Ph is changed from 80V to 500V. The solid line F is the level of the collector voltage Vc. The characteristics when the amplitude of the lighting pulse Ph is changed from 80V to 500V are shown.

[0158] As shown in Fig. 30, the dynamic range of the emission luminance change with respect to the lighting pulse Ph is wider than when the collector voltage Vc is 7 kV and the force is 3 kV. It can be seen that it is advantageous in improving the above. This tendency is a force that seems to be more advantageous as the level of the collector voltage Vc is increased. In this case as well, it is preferable to set the optimum value in relation to the withstand voltage and power consumption of the signal transmission system.

Here, one driving method of the display 100 described above will be described with reference to FIG. 31 and FIG. FIG. 31 typically shows the operation of pixels in 1 row, 1 column, 2 rows, 1 column, and n rows, 1 column. The electron-emitting device 10A used here has a coercive voltage vl at point p2 in FIG. 16 of, for example, 20V, a coercive voltage v2 at point p5 of + 70V, a voltage v3 at point p3 of −50V, and a voltage at point p4. v4 has the characteristics of + 50V.

Further, as shown in FIG. 31, when the display period of one image is one frame, one charge accumulation period Td and one light emission period Th are included in the one frame, One charge accumulation period Td includes n selection periods Ts. Since each selection period Ts becomes the selection period Ts of the corresponding row, it does not correspond !, and the nl number of rows becomes the non-selection period Tn. [0161] Then, in this driving method, during the charge accumulation period Td, all the electron-emitting devices 10A are scanned, and pixels corresponding to a plurality of electron-emitting devices 10A corresponding to ON-target (light-emitting target) pixels, respectively. By applying a voltage according to the brightness level of the pixel, charges (electrons) of an amount corresponding to the brightness level of the pixel corresponding to each of the plurality of electron-emitting devices 10A corresponding to the ON target pixel are accumulated, and the next light emission In period Th, a constant voltage is applied to all the electron-emitting devices 10A, and an amount of electrons corresponding to the luminance level of the corresponding pixel is emitted from the plurality of electron-emitting devices 10A corresponding to the ON target pixels. Thus, the ON target pixel emits light.

More specifically, as shown in FIG. 32, first, in the selection period Ts of the first row, for example, a selection signal Ss of 50 V is supplied to the row selection line 106 of the first row, and the other For example, a non-selection signal Sn of 0 V is supplied to the row selection line 106 of the row. Among the pixels in the first column, the voltage of the pixel signal Sd supplied to the signal line 108 of the pixel to be turned ON (light emission) is in the range of 0 V or more and 30 V or less, and each of the corresponding pixels The voltage depends on the brightness level. If the luminance level is maximum, it will be 0V. The modulation according to the luminance level of the pixel signal Sd is performed through the amplitude modulation circuit 122 shown in FIG. 19 and the pulse width modulation circuit 126 shown in FIG.

[0163] Accordingly, between the upper electrode 14 and the lower electrode 16 of the electron-emitting device 10A corresponding to each pixel to be turned ON in the first row, a voltage of -50 V or more and -20 V or less is applied depending on the luminance level. Is applied. As a result, electrons corresponding to the applied voltage are accumulated in each of the electron-emitting devices 10A described above. For example, since the electron-emitting device corresponding to the pixel in the first row and the first column has, for example, the maximum luminance level, the state becomes a point p3 in the characteristic of FIG. The maximum amount of electrons is accumulated in the exposed area.

[0164] The voltage of the pixel signal Sd supplied to the electron-emitting device 10A corresponding to the pixel indicating OFF (quenching) is, for example, 50 V. Thus, the electron-emitting device corresponding to the OFF target pixel 0V is applied to 10A, which is the state of point pi in the characteristics of Fig. 16, and no electrons are stored.

[0165] After the supply of the pixel signal Sd to the first row is completed, in the selection period Ts of the second row, 2 A 50V selection signal Ss is supplied to the row selection line 106 of the row, and a 0V non-selection signal Sn is supplied to the row selection lines 106 of the other rows. Also in this case, a voltage of 50V or more and 20V or less is applied between the upper electrode 14 and the lower electrode 16 of the electron-emitting device 10A corresponding to the pixel to be turned on (light emission) according to the luminance level. At this time, for example, in a non-selected state, a voltage of 0 V or more and 50 V or less is applied between the upper electrode 14 and the lower electrode 16 of the electron-emitting device 10A corresponding to the pixel in the first row. Since the voltage does not reach point 4 of the 16 characteristics, electrons are not emitted from the electron-emitting device 10A corresponding to the pixel to be turned ON (light emission) in the first row. That is, the pixel in the first row in the non-selected state is not affected by the pixel signal Sd supplied to the pixel in the second row in the selected state.

[0166] Similarly, in the selection period Ts of the nth row, the 50V selection signal Ss is supplied to the row selection line 106 of the nth row, and the 0V non-selection signal is supplied to the row selection line 106 of the other row. Sn is supplied. Also in this case, a voltage of −50 V or more and −20 V or less is applied between the upper electrode 14 and the lower electrode 16 of the electron-emitting device 10A corresponding to the pixel to be turned ON (light emission) according to the luminance level. . At this time, a voltage of 0 V or more and 50 V or less is applied between the upper electrode 14 and the lower electrode 16 of the electron-emitting device 10A corresponding to each pixel in one row and one (n−1) row in the non-selected state. Of these non-selected pixels, when electrons are emitted from the electron-emitting device 10A corresponding to the pixel to be turned ON (light emission), nothing happens.

[0167] The light emission period Th starts when the selection period Ts of the n-th row has elapsed. In this light emission period Th, a reference voltage (for example, 0 V) is applied to the upper electrode 14 of the all-electron emitting device 10A through the signal supply circuit 112, and a voltage (350 V) is applied to the lower electrode 16 of the all-electron emitting device 10A. Pulse power supply 118 -400V + row selection circuit 110 power supply voltage 50V) is applied. As a result, a high voltage (+350 V) is applied between the upper electrode 14 and the lower electrode 16 of the all-electron emitting device 10A. All the electron-emitting devices 10A are in the state of the characteristic point p6 in FIG. 16, and as shown in FIG. 18C, electrons are transmitted from the portion where the electrons are accumulated in the emitter section 12 through the penetrating section 20. Released. Of course, electrons are also emitted from the vicinity of the outer periphery of the upper electrode 14.

That is, electrons are emitted from the electron-emitting device 10A corresponding to the pixel to be turned ON (light emission). The emitted electrons are guided to the collector electrode 132 corresponding to these electron-emitting devices 10A to excite the corresponding phosphor 134 and emit light. Thereby, the surface force image of the transparent plate 130 is displayed.

[0169] Similarly, in the frame unit, electrons are accumulated in the electron-emitting device 10A corresponding to the pixel to be turned ON (light emission) in the charge accumulation period Td, and the electrons accumulated in the light emission period Th are By emitting and emitting fluorescent light, the surface force of the transparent plate 130 is also displayed as a moving image or a still image.

Thus, the electron-emitting device according to the first embodiment has a plurality of electron-emitting devices 10A arranged according to a plurality of pixels, and the electron-emitting devices from each electron-emitting device 10A This makes it easy to apply to the display 100 that displays images.

[0171] For example, as described above, all the electron-emitting devices are scanned during the charge accumulation period Td in one frame, and the luminance of each of the pixels corresponding to the plurality of electron-emitting devices 10A corresponding to the ON target pixels is determined. By applying a voltage according to the level, an amount of charge corresponding to the luminance level of the pixel corresponding to each of the plurality of electron-emitting devices 10A corresponding to the ON target pixel is accumulated, and in the next light emission period Th. By applying a constant voltage to all the electron-emitting devices 10A, a plurality of electron-emitting devices 10A corresponding to the pixels to be turned on emit electrons corresponding to the luminance level of the corresponding pixels, and turn on. The target pixel can be made to emit light.

[0172] In the first embodiment, for example, the relationship between the voltage V3 at which electrons are accumulated and saturated and the voltage V4 at which the emission of electrons starts is 1≤ I V4 I / I V3 I ≤1.5.

[0173] Usually, for example, the electron-emitting devices 10A are arranged in a matrix, synchronized in the horizontal scanning period, and the electron-emitting devices 10A are selected in units of one row, and the selected electron-emitting devices 10A are selected. Thus, when the pixel signal Sd corresponding to the luminance level of each pixel is supplied, the pixel signal Sd is also supplied to the non-selected pixel.

[0174] When the electron-emitting device 10A in the non-selected state emits, for example, electrons due to the influence of the pixel signal Sd, there is a problem that the image quality of the display image is deteriorated and the contrast is lowered.

However, since the first embodiment has the above-described characteristics, the selected state electrons The voltage level of the pixel signal Sd supplied to the emitting element 10A is set to an arbitrary voltage from the reference voltage to the voltage V3, and a signal having a polarity opposite to that of the pixel signal Sd is supplied to the non-selected electron emitting element 10A, for example. Even in a simple voltage relationship, the memory effect at each pixel can be realized without the pixel in the non-selected state being affected by the pixel signal Sd to the pixel in the selected state. High contrast can be achieved.

[0176] On the other hand, in this display 100, necessary charges are accumulated in all the electron-emitting devices 10A during the charge accumulation period Td, and electrons are emitted from all the electron-emitting devices 10A during the subsequent light-emitting period Th. A voltage necessary for the ON is applied, and electrons are emitted from the plurality of electron-emitting devices 10A corresponding to the ON target pixels so that the ON target pixels emit light.

[0177] Normally, when a pixel is constituted by the electron-emitting device 10A, it is necessary to apply a high voltage to the electron-emitting device 10A in order to cause the pixel to emit light. For this reason, when charges are accumulated during scanning of pixels and further light emission is performed, it is necessary to apply a high voltage over a period during which one image is displayed (for example, one frame), resulting in high power consumption. There is a problem of becoming. Also, the circuit that selects each electron-emitting device 10A and supplies the pixel signal Sd needs to be a circuit that supports high voltage.

However, in this example, after charges are accumulated in all the electron-emitting devices 1 OA, a voltage is applied to all the electron-emitting devices 10A so that the pixels corresponding to the ON-target electron-emitting devices 10A emit light. It is a thing.

[0179] Accordingly, the period Th in which the voltage for emitting electrons (emission voltage) is applied to all the electron-emitting devices 10A is naturally shorter than one frame, and the first period shown in FIGS. 26A and 26B is used. The power consumption can be greatly reduced compared to the case where charge accumulation and light emission are performed during scanning to the pixel because the period of applying the emission voltage can be shortened so that the power of the experimental example 1 can also be achieved. Can be made.

[0180] Further, since the period Td for accumulating charges in the electron-emitting device 10A and the period Th for emitting electrons from the electron-emitting device 10A corresponding to the ON target pixel are separated, each electron-emitting device 10A has a brightness level. The circuit for applying the corresponding voltage can be driven at a low voltage.

[0181] Further, the pixel signal corresponding to the image and the charge accumulation period Td selection signal SsZ non-selection signal S n is the force that needs to be driven for each row or column. As can be seen from the above-described embodiments, the drive voltage may be several tens of volts. Therefore, an inexpensive multi-output driver used in a fluorescent display tube or the like is used. Can be used. On the other hand, in the light emission period Th, the voltage that sufficiently discharges electrons may be higher than the drive voltage, but since all the pixels to be turned on need to be driven together, No circuit parts are required. For example, it is sufficient to have a drive circuit with only one output composed of high withstand voltage discreet components, which is advantageous in that the cost is low and the circuit scale is small.

[0182] Next, an electron-emitting device 10B according to a second embodiment will be described with reference to FIG.

As shown in FIG. 33, the electron-emitting device 10B according to the second embodiment has substantially the same configuration as the electron-emitting device 10A according to the first embodiment described above. The constituent material of the electrode 14 is the same as that of the lower electrode 16, the thickness t of the upper electrode 14 is thicker than 10 μm, and the penetrating part 20 is etched (wet etching, dry etching), liftoff, laser, etc. It is characterized in that it is artificially formed using. As the shape of the penetrating portion 20, the shape of the hole 32, the shape of the notch 44, and the shape of the slit 48 can be adopted as in the first embodiment described above.

[0184] Furthermore, the lower surface 26a of the peripheral portion 26 of the penetrating portion 20 in the upper electrode 14 is gradually inclined upward as it is directed toward the center of the penetrating portion 20. This shape can be easily formed by using, for example, lift-off.

[0185] Also in the electron-emitting device 10B according to the second embodiment, similarly to the electron-emitting device 10A according to the first embodiment described above, high electric field concentration can be easily generated, and In addition, it is possible to increase the number of electron emission locations, to achieve high output and high efficiency for electron emission, and to enable low voltage driving (low power consumption).

Further, like the electron-emitting device lOBa according to the first modification shown in FIG. 34, the floating electrode 50 may be present in a portion corresponding to the penetrating portion 20 in the upper surface of the emitter portion 12.

[0187] Further, like the electron-emitting device lOBb according to the second modification shown in FIG. 35, an electrode having a substantially T-shaped cross section may be formed as the upper electrode 14. Further, like the electron-emitting device lOBc according to the third modification shown in FIG. 36, the shape of the upper electrode 14, particularly, the shape in which the peripheral portion 26 of the penetrating portion 20 of the upper electrode 14 is raised may be used. . In this case, the film material to be the upper electrode 14 may include a material that is gasified during the firing process. Thereby, in the firing step, the material is gasified, and as a result, a large number of through portions 20 are formed in the upper electrode 14 and the peripheral portion 26 of the through portion 20 is lifted.

[0189] Next, an electron-emitting device 10C according to a third embodiment will be described with reference to FIG.

As shown in FIG. 37, the electron-emitting device 10C according to the third embodiment is made of a force having substantially the same configuration as the electron-emitting device 10A according to the first embodiment described above, for example, ceramics. The lower electrode 16 is formed on the substrate 60, the emitter 12 is formed on the substrate 60 and covers the lower electrode 16, and the upper electrode is formed. 14 is different in that 14 is formed on the emitter 12.

[0191] Inside the substrate 60, a space 62 for forming a thin portion described later is provided at a position corresponding to a portion where each of the emitter portions 12 is formed. The void 62 has a small diameter provided on the other end surface of the substrate 60 and communicates with the outside through the through hole 64.

[0192] In the substrate 60, the portion where the void 62 is formed is thin (hereinafter referred to as the thin portion 66), and the other portions are thick and are fixed to support the thin portion 66. It is designed to function as part 68.

That is, the substrate 60 is a laminate of the substrate layer 60A as the lowermost layer, the spacer layer 60B as the intermediate layer, and the thin plate layer 60C as the uppermost layer, and among the spacer layers 60B, the emitter 60 It can be grasped as an integral structure in which a void 62 is formed at a location corresponding to the portion 12. The substrate layer 60A functions not only as a reinforcing substrate but also as a wiring substrate. The substrate 60 may be formed by single firing of the substrate layer 60A, the spacer layer 60B, and the thin plate layer 60C, or may be formed by bonding these layers 60A-60C.

[0194] The thin-walled portion 66 is preferably a high heat resistant material. The reason is that the thin-walled portion 66 is directly supported by the fixing portion 68 without using the material having poor heat resistance such as an organic adhesive for the emitter portion 12. In the case of a structure to be held, it is preferable that the thin portion 66 is a high heat resistant material so that the thin portion 66 does not change quality at least when the emitter portion 12 is formed.

[0195] In addition, the thin-walled portion 66 includes a wiring that leads to the upper electrode 14 formed on the substrate 60, and the lower electrode 1

In order to achieve electrical separation from the wiring leading to 6, is preferably an electrical insulating material.

[0196] Therefore, the material of the thin-walled portion 66 may be a highly heat-resistant metal or a material such as a hollow whose surface is covered with a ceramic material such as glass, but ceramics is most suitable. .

[0197] Ceramics constituting the thin-walled portion 66 include, for example, stabilized acid zirconium, acid aluminum, magnesium oxide, titanium oxide, spinel, mullite, aluminum nitride, silicon nitride, glass A mixture of these can be used. Of these, aluminum oxide and stabilized acid-zirconium force are preferred from the viewpoint of strength and rigidity. Stabilized zirconium oxide is particularly suitable from the viewpoints of relatively high mechanical strength, relatively high toughness, and relatively small chemical reaction with the upper electrode 14 and the lower electrode 16. is there. Note that stabilized zirconium oxide includes stabilized zirconium oxide and partially stabilized zirconium oxide. Stabilized zirco oxide

-UM has a cubic crystal structure, so no phase transition occurs.

[0198] On the other hand, zirconium oxide has a phase transition between monoclinic and tetragonal crystals at around 1000 ° C, and cracks may occur during such phase transition. Oxide stabilized zirconium two © beam is calcium oxide, magnesium oxide, yttrium oxide, scandium oxide, acid I spoon ytterbium, cerium oxide, a stabilizer such as rare earth metal Sani匕物, 1 one 30 mole ⁰ / _{Contains 0} . In order to improve the mechanical strength of the substrate 60, it is preferable that the stabilizer contains yttrium oxide. In this case, yttrium oxide, preferably 1. 5-6 mole ^_0/0, further preferably contains 2-4 mole ^_0/0, further comprising containing the aluminum oxide 0.5 1 5 mole ^_0/0 It is preferable.

[0199] Further, the force that can make the crystal phase a cubic + monoclinic mixed phase, a tetragonal + monoclinic mixed phase, a cubic + tetragonal + monoclinic mixed phase, etc. From the viewpoints of strength, toughness, and durability, the main crystal phase is a tetragonal or tetragonal + cubic mixed phase. [0200] When the substrate 60 also has a ceramic force, a relatively large number of crystal grains constitute the substrate 60. In order to improve the mechanical strength of the substrate 60, the average grain size of the crystal grains is preferably 0.05-2 m, more preferably 0.1-.

[0201] On the other hand, the fixing portion 68 preferably has a ceramic force, but may be the same ceramic as the material of the thin-walled portion 66 or may be different. As the ceramics constituting the fixed portion 68, for example, as in the material of the thin portion 66, for example, stabilized acid zirconium, acid medium, magnesium oxide, titanium oxide, spinel, mullite. Aluminum nitride, silicon nitride, glass, a mixture thereof, or the like can be used.

[0202] In particular, the substrate 60 used in the electron-emitting device 10C is made of a material mainly composed of acid zirconium, a material mainly composed of acid aluminum, or a material mainly composed of a mixture thereof. Is preferably employed. Among them, a material mainly composed of zirconium oxide is preferred.

[0203] Although a clay or the like may be added as a sintering aid, it is necessary to adjust the aid component so as not to include excessively glassy substances such as silicon oxide and boron oxide. This is because these easily vitrified materials are advantageous in bonding the substrate 60 and the emitter 12, but promote the reaction between the substrate 60 and the emitter 12, and the predetermined emitter 12 is formed. This is because it is difficult to maintain the characteristics, and as a result, the device characteristics are deteriorated.

[0204] That is, it is preferable to limit the amount of silicon oxide or the like in the substrate 60 to 3% or less, more preferably 1% or less by weight. Here, the main component means a component present in a ratio of 50% or more by weight.

[0205] Further, the thickness of the thin portion 66 and the thickness of the emitter portion 12 are preferably the same dimension. This is because when the thickness of the thin portion 66 is extremely thicker than the thickness of the emitter portion 12 (by one digit or more), the thin portion 66 acts to prevent the shrinkage of the emitter portion 12 from firing shrinkage. The stress at the interface between the portion 12 and the substrate 60 becomes large, and it is easy to peel off. On the other hand, if the thickness dimension is approximately the same, the substrate 60 (thin wall portion 66) can easily follow the firing shrinkage of the emitter portion 12, which is preferable for an integrated substrate. Specifically, it is preferable that the thickness of the thin-walled portion 66 is 1 to 100 m 3 to 50 m force S, more preferably 5 to force S Even more preferred. On the other hand, the thickness of the emitter portion 12 is preferably 5-100 m, more preferably 5-30 μm, even more preferably 5-30 μm.

[0206] And, as a method of forming the emitter portion 12 on the substrate 60, various thick film forming methods such as a screen printing method, a dubbing method, a coating method, an electrophoresis method, an ion beam method, a sputtering method, Various thin film formation methods such as vacuum deposition, ion plating, chemical vapor deposition (CVD), and plating can be used.

[0207] In addition, as a firing process for the electron-emitting device 10C, a material that becomes the lower electrode 16, a material that becomes the emitter portion 12, and a material that becomes the upper electrode 14 are sequentially laminated on the substrate 60, and then an integrated structure is formed. The substrate may be fired, or the lower electrode 16, the emitter portion 12, and the upper electrode 14 may be heat-treated (fired) each time they are formed to be integrated with the substrate 60. Depending on the method of forming the upper electrode 14 and the lower electrode 16, a heat treatment (firing treatment) for integration is not required! ,In some cases.

[0208] The temperature related to the baking treatment for integrating the substrate 60, the emitter section 12, the upper electrode 14, and the lower electrode 16 is in the range of 500-1400 ° C, preferably 1000-1400. It should be in the range of ° C. Furthermore, when heat treatment is performed on the film-like emitter 12, the firing process is performed while controlling the atmosphere together with the evaporation source of the emitter 12 so that the yarn formation of the emitter 12 does not become unstable at high temperatures! Preferred to do.

[0209] Alternatively, a method may be employed in which the emitter portion 12 is covered with an appropriate member and fired so that the surface of the emitter portion 12 is not directly exposed to the firing atmosphere. In this case, it is preferable to use the same material as the substrate 60 as the covering member.

[0210] In the electron-emitting device 10C according to the third embodiment, the emitter 12 contracts during firing, and the stress generated during the contraction passes through deformation of the void 62 and the like. Thus, the emitter 12 can be sufficiently densified. By improving the densification of the emitter section 12, the withstand voltage is improved, and the polarization inversion and the polarization change in the emitter section 12 are efficiently performed, and the characteristics as the electron-emitting device 10C are improved. become.

[0211] In the third embodiment described above, a substrate having a three-layer structure is used as the substrate 60. However, as shown in the electron-emitting device lOCa according to the modification of FIG. 38, the lowermost substrate layer 60A is used. Saving You can use the abbreviated two-layer substrate 60a.

It should be noted that the electron-emitting device according to the present invention is not limited to the above-described embodiment, but can of course have various configurations without departing from the gist of the present invention.

Claims

The scope of the claims

[1] It has a substance (12) that becomes an emitter composed of a dielectric, and a first electrode (14) and a second electrode (16) to which a driving voltage (Va) for electron emission is applied. And

The first electrode (14) is formed on a first surface of the substance (12) serving as the emitter, and the second electrode (16) is a second surface of the substance (12) serving as the emitter. And at least the first electrode (14) has a plurality of through portions (20) from which the substance (12) serving as the emitter is exposed, and the first electrode (14) includes: The surface (26a) facing the substance (12) serving as the emitter in the peripheral part (26) of the penetrating part (20) is the substance (1

2) An electron-emitting device characterized in that the force is separated.

[2] The electron-emitting device according to claim 1,

At least the first surface of the substance (12) serving as the emitter is formed with concaves and convexes (22) due to grain boundaries of the dielectric,

The electron-emitting device according to claim 1, wherein the first electrode (14) has the penetrating portion (20) formed in a portion corresponding to the concave portion (24) in the grain boundary of the dielectric.

[3] The electron-emitting device according to claim 1,

The first surface of the substance (12) serving as the emitter and the substance (12) serving as the emitter in the peripheral part (26) of the through-hole (20) of the first electrode (14) Electron emitting device characterized in that the maximum angle formed by the surface (26a) is 0 force 1 ° ≤ Θ≤60 °.

[4] The electron-emitting device according to claim 1,

The first surface of the substance (12) serving as the emitter and the substance (12) serving as the emitter in the peripheral part (26) of the through-hole (20) of the first electrode (14) The electron-emitting device characterized in that the maximum distance d along the vertical direction between the surface (26a) and the surface (26a) is 0 m <d≤10 m.

[5] The electron-emitting device according to claim 1,

An electron-emitting device, wherein a floating electrode (50) is present in a portion corresponding to the penetrating portion (20) in the first surface of the substance (12) serving as the emitter.

[6] The electron-emitting device according to claim 1,

The electron-emitting device, wherein the through portion (20) is a hole (32).

[7] The electron-emitting device according to claim 6,

The electron-emitting device characterized in that an average diameter of the holes (32) is 0.1 m or more and 10 μm or less.

[8] The electron-emitting device according to claim 1,

The electron-emitting device, wherein the penetrating part (20) is a notch (44).

[9] The electron-emitting device according to claim 8,

The penetrating part (20) is a comb-shaped notch (44),

[10] The electron-emitting device according to claim 8,

The electron emission element, wherein an average width of the notches (44) is 0.1 m or more and 10 μm or less.

[11] The electron-emitting device according to claim 1,

The electron-emitting device, wherein the penetrating portion (20) is a slit (48) having an arbitrary shape.

[12] The electron-emitting device according to claim 11,

The electron emission element, wherein an average width of the slit (48) is 0.1 m or more and 10 μm or less.

[13] Emitter material (12) composed of dielectric,

A first electrode (14) formed to be in contact with the first surface of the substance (12) serving as the emitter;

A second electrode (16) formed so as to be in contact with the second surface of the substance (12) serving as the emitter,

At least the first electrode (14) has a plurality of through portions (20) through which the substance (12) serving as the emitter is exposed,

In electrical operation, between the first electrode (14) and the second electrode (16), a capacitor (C1) made of the substance (12) serving as the emitter,

A plurality of capacitors (between the first electrode (14) and the substance (12) serving as the emitter by the plurality of through portions (20) formed in the first electrode (14). Ca) An electron-emitting device characterized in that an aggregate (C2) is formed.

[14] In an electron-emitting device having an electron-emitting portion,

By applying a negative voltage, the amount of positive charge accompanying the accumulation of electrons and the amount of negative charge change to an equilibrium state (first state), and the amount of negative charges increases with the accumulation of further electrons. More than V, change to state (second state),

When the second state force positive voltage is applied, the amount of positive charge and the amount of negative charge associated with electron emission change to an equilibrium state (third state). When the amount changes to a state greater than the amount of negative charge,

When the applied voltage for changing to the first state is VI and the applied voltage for changing to the third state is V2,

I VI I <I V2 I

An electron-emitting device having the following characteristics:

[15] The electron-emitting device according to claim 14,

1. 5 X I VI I <I V2 I

An electron-emitting device characterized in that

[16] The electron-emitting device according to claim 14,

When the rate of change in the amount of positive charge and the amount of electrons in the first state is Δ Q1Z Δ VI, and the rate of change in the amount of positive charge and the amount of electrons in the third state is Δ Q2Z Δ V2,

(A Ql / AVl)> (A Q2 / AV2)

An electron-emitting device characterized in that

[17] The electron-emitting device according to claim 14,

Let V3 be the voltage at which electrons accumulate and become saturated, and V4 be the voltage at which electron emission starts.

1≤ I V4 I / I V3 I ≤1.5

An electron-emitting device characterized in that

[18] It has a substance (12) to be an emitter composed of a dielectric, and a first electrode (14) and a second electrode (16) to which a driving voltage (Va) for electron emission is applied For electron-emitting devices! ,,, By applying a voltage in one direction between the first electrode (14) and the second electrode (16), the substance (12) serving as the emitter is polarized in the negative direction. The polarization is reversed. When the voltage that changes to the state is the first coercive voltage vl, and the voltage whose polarization changes again in the one direction by applying a voltage from this state to the other direction is the second coercive voltage v2,

vl <0 or v2 <0 and

I vl I <I v2 I

An electron-emitting device having the following characteristics:

[19] The electron-emitting device according to claim 18,

1. 5 X I vl I <I v2 I

An electron-emitting device characterized in that

[20] The electron-emitting device according to claim 18,

When the rate of change in polarization when the first coercive voltage is applied is Δ qlZ Δνΐ, and the rate of change in polarization when the second coercive voltage is applied is A q2Z Av2,

(A ql / Avl)> (A q2 / Av2)

An electron-emitting device characterized in that

[21] The electron-emitting device according to claim 18,

If the voltage at which electrons are accumulated and saturated is v3, and the voltage at which electrons start to be emitted ^ v4,

1≤ I v4 I / I v3 I ≤1.5

An electron-emitting device characterized in that