JP4884115B2 - Electron emitter - Google Patents

Description

  The present invention relates to an electron-emitting device including an emitter portion made of a dielectric, a lower electrode formed at a lower portion of the emitter portion, and an upper electrode formed at an upper portion of the emitter portion.

  Conventionally, an emitter portion made of a dielectric, a lower electrode (lower electrode layer) formed on the lower surface of the emitter portion, and an upper electrode (upper electrode layer) formed on the upper surface of the emitter portion and having many fine through holes There is known an electron-emitting device that emits electrons from a fine through hole of an upper electrode by reversing a dielectric dipole (polarization reversal).

  In this element, first, a voltage that makes the potential of the upper electrode lower than the potential of the lower electrode is applied between the upper electrode and the lower electrode (between the upper and lower electrodes). In other words, when the potential of the lower electrode is used as a reference, a negative potential is applied to the upper electrode. As a result, the dipole of the emitter section is inverted so that the positive electrode side faces the upper electrode side. That is, negative polarization reversal occurs. As a result, electrons are supplied from the upper electrode to the upper part of the emitter part, and accumulated in the upper part of the emitter part. Next, a voltage is applied between the upper and lower electrodes so that the potential of the upper electrode is the same as the potential of the lower electrode. Thereafter, a voltage that makes the potential of the upper electrode higher than the potential of the lower electrode is applied between the upper and lower electrodes. In other words, when the potential of the lower electrode is used as a reference, a positive potential is applied to the upper electrode.

Thereby, the dipole of the emitter section is inverted so that the negative electrode side faces the upper electrode side. That is, positive polarization inversion occurs. As a result, the electrons accumulated in the upper part of the emitter part receive a Coulomb repulsive force from the dipole and are emitted through the fine through hole of the upper electrode. A dielectric having a relative dielectric constant of, for example, 1000 or more has been used as the dielectric of the emitter that performs such an electron emission operation (see Patent Document 1).
JP 2005-174905 A (paragraph 0063)

  Such an electron-emitting device can be applied to various devices that require emitted electrons, such as a display, a liquid crystal backlight, an electron irradiation device, and an electronic component manufacturing device. Therefore, naturally, it is preferable that the amount of emitted electrons (the amount of emitted electrons) is large. However, conventionally, in order to emit more electrons, sufficient studies have not been made as to what kind of characteristics it is preferable to use for the emitter portion.

  Therefore, the present inventor conducted an experiment to measure the amount of emitted electrons by using a dielectric having various characteristics for the emitter portion. The inventors paid attention to the ratio Pr / P of the remanent polarization amount Pr to the total polarization amount P of the electron-emitting device when analyzing the experimental results.

  Furthermore, the inventor stated that “the amount of polarization when the potential of the upper electrode is set lower than the potential of the lower electrode, and the residual polarization when the potential of the upper electrode is set to the same potential as the potential of the lower electrode. Attention was also paid to the ratio ΔP / P of the negative polarization decrease amount ΔP to the total polarization amount P, where “the absolute value of the difference between the two” is defined as the negative polarization decrease amount ΔP.

  When electrons are emitted from such an electron-emitting device, the relationship between the voltage (applied voltage) applied to the emitter made of dielectric (between the upper and lower electrodes) and the amount of charge appearing between the upper and lower electrodes of the electron-emitting device (voltage− For example, as shown in FIG. 1, the polarization characteristic has a relationship having hysteresis.

Here, the applied voltage is the potential of the upper electrode (the potential of the upper electrode minus the potential of the lower electrode) when the potential of the lower electrode is used as a reference. That is, the applied voltage is equal to the element voltage Vka.
The total polarization amount P is a charge amount in a state in which the charge amount does not increase even when the applied voltage is increased (positive maximum charge amount, point A in FIG. 1), and the charge amount is decreased even if the applied voltage is decreased. This is the difference from the charge amount (negative maximum charge amount, point B in FIG. 1) in a state where there is no charge (the negative charge amount does not increase). That is, the total polarization amount P is a charge amount corresponding to the length of the line segment AB in FIG.

  The remanent polarization amount Pr is obtained when the applied voltage becomes zero by decreasing the applied voltage from the applied voltage (positive maximum applied voltage) Vp in a state where the amount of charge does not increase even when the applied voltage is increased. Increase the applied voltage from the charge amount (positive residual charge amount, point C in FIG. 1) and the applied voltage (negative maximum applied voltage) Vm in a state where the charge amount does not decrease even if the applied voltage is decreased. Is the difference from the charge amount when the applied voltage becomes zero (negative residual charge amount, point D in FIG. 1). That is, the remanent polarization amount Pr is a charge amount corresponding to the length of the line segment CD in FIG.

  The negative polarization decrease amount ΔP is a difference (absolute value) between the negative maximum charge amount (point B in FIG. 1) and the negative residual charge amount (point D in FIG. 1) in FIG. This is the charge amount corresponding to the length of the line segment DB.

  As described above, the inventor paid attention to the ratio Pr / P of the remanent polarization amount Pr with respect to the total polarization amount P, and investigated the relationship between the ratio Pr / P and the amount of emitted electrons. As a result, the inventors have found that the amount of emitted electrons is remarkably increased when the ratio Pr / P is 0.7 or more.

The reason is estimated as follows.
(Estimation Reason 1) The ratio Pr / P of the residual polarization quantity Pr to the total polarization quantity P is large, which means that the negative polarity residual polarization quantity (the charge quantity corresponding to the length of the line segment OB in FIG. , Point O is also the origin) is large. If the amount of negative remanent polarization is large, electrons accumulated in the upper part of the emitter due to the applied voltage being set to a negative voltage will be emitted when the applied voltage becomes 0 or a positive voltage near 0. It can be securely held at the top of the part. Therefore, the number of electrons that can be emitted from the emitter portion does not drop significantly until the positive side polarization reversal occurs. As a result, the amount of emitted electrons becomes a large value. On the other hand, when the amount of negative remanent polarization is small, when the applied voltage becomes 0 or a positive voltage close to 0, the electrons accumulated in the upper part of the emitter part leak from the emitter part to the upper electrode. End up. Therefore, the amount of electrons that can be emitted from the emitter section at the time when positive side polarization reversal occurs is reduced. As a result, the amount of emitted electrons is reduced.

  (Estimation reason 2) According to the experiment, when the ratio Pr / P of the remanent polarization amount Pr to the total polarization amount P is large, the applied voltage increases in the vicinity of the voltage (positive coercive electric field voltage) that causes the positive polarization inversion. The rate of increase in the amount of charge at the top of the emitter at this time (hereinafter simply referred to as “the rate of change in charge amount at the time of positive side polarization reversal”) is large. That is, when the ratio Pr / P is large, the fact that the slope of the hysteresis curve in the region surrounded by the broken line LC in the graph of FIG. This is considered to be because when the ratio Pr / P is large, the positive side polarization inversion of the dipoles of the emitter portion occurs all at once in a short time. When positive side polarization reversal occurs simultaneously within a short time, the electrons accumulated in the upper part of the emitter section receive a large Coulomb repulsive force from the dipole within a short time.

  Further, as shown in FIG. 2, when attention is paid to the point Q at the top of the emitter section 13, the emitter section 13 which is a dielectric between the lower electrode 12 and the point Q has a capacitor Cf (capacitance value = Cfer). A capacitor Cg (capacitance value = Cgap) is formed in the space between the upper surface of the emitter section 13 and the lower surface of the upper electrode 14 at the point Q. Therefore, at the position of the point Q, the upper and lower electrodes can be regarded equivalently as being connected by a line in which these capacitors Cf and Cg are connected in series.

  In this case, when the voltage between the electrodes of the capacitor Cg and the voltage between the electrodes of the capacitor Cf are expressed as Vgap and Vfer, respectively, the voltage Vin applied between the upper and lower electrodes is divided into the voltage Vgap and the voltage Vfer. And, when the positive side polarization inversion charge amount change rate is large at the time of positive side polarization inversion, it means that the capacitance (Cfer) of the capacitor Cf at that time is large. It means that it is getting bigger. Therefore, electrons are strongly accelerated by the large voltage Vgap and are vigorously emitted in the vertical direction (upward) with respect to the plane formed by the upper electrode 14 through the fine through hole 14a.

  For these reasons, the number of electrons leaking to the upper electrode is reduced, and most of the electrons are emitted above the upper electrode. As a result, the amount of emitted electrons becomes a large value.

  As described above, by using a dielectric having a ratio Pr / P of the residual polarization amount Pr to the total polarization amount P of 0.7 or more in the emitter portion, or the negative polarization decrease amount ΔP with respect to the total polarization amount P. By using a dielectric having a ratio ΔP / P of 0.1 or less, an electron-emitting device having a very large amount of emitted electrons can be provided.

  Embodiments of an electron emission device according to the present invention will be described below with reference to the drawings. This electron emission device can be suitably used for various devices that require an electron emission source, such as a display, a backlight for liquid crystal, an electron irradiation device, and an electronic component manufacturing device.

(Constitution)
FIG. 3 is a configuration diagram of the entire liquid crystal backlight to which the electron-emitting device according to the embodiment of the present invention is applied. The backlight includes an electron emission device 10, a drive voltage application unit 20, and a bias power supply unit 30.

The electron emission device 10 includes an electron emission element 10A.
The electron-emitting device 10 </ b> A includes a substrate 11, a lower electrode (lower electrode layer) 12, an emitter section 13, and an upper electrode (upper electrode layer) 14.

  As shown in FIGS. 3 and 4, the substrate 11 has an upper surface and a lower surface parallel to a plane (XY plane) formed by the X axis and the Y axis orthogonal to each other. It is a thin plate body having a thickness direction in the Z-axis direction orthogonal to each. The substrate 11 is made of a material mainly composed of zirconium oxide (for example, glass or ceramics).

  The lower electrode 12 is made of a conductive material (here, silver or platinum), and is formed in a layer on the upper surface of the substrate 11. That is, the lower electrode 12 is a thin film electrode having an upper surface and a lower surface parallel to the XY plane, and the thickness direction is the Z-axis direction.

  The emitter section 13 is made of a ferroelectric material (for example, ternary material PMN-PT-PZ of lead magnesium niobate (PMN), lead titanate (PT) and lead zirconate (PZ)). The ferroelectric constituting the emitter section 13 will be described in detail later. The emitter section 13 is a thin plate body having an upper surface and a lower surface parallel to the XY plane, and the thickness direction is the Z-axis direction. The emitter section 13 is formed on the upper surface of the lower electrode 12. On the upper surface of the emitter section 13, as shown in an enlarged view in FIG. 4, irregularities due to dielectric grain boundaries 13 a are formed.

  The upper electrode 14 is made of a conductive material (here, platinum), and is formed in a layer shape on the upper surface of the emitter section 13. That is, the upper electrode 14 is a thin film electrode having an upper surface and a lower surface parallel to the XY plane, and the thickness direction is the Z-axis direction. The upper electrode 14 is formed on the emitter section 13 so as to sandwich the emitter section 13 between the lower electrode 12 and face the lower electrode 12. As shown in FIG. 4 and FIG. 5 which is a partially enlarged plan view of the upper electrode 14, a plurality of fine through holes 14 a are formed in the upper electrode 14. A portion of the peripheral portion of the fine through hole 14a facing the emitter portion 13 (the upper surface of the emitter portion 13) is separated from the emitter portion 13 (the upper surface of the emitter portion 13) by a predetermined distance. The structure of the upper electrode 14 is also referred to as a “saddle structure”.

  The lower electrode 12, the emitter section 13, and the upper electrode 14 made of an organic metal paste (for example, platinum resinate paste) are integrated by a baking process. By this baking process for integration, the film to be the upper electrode 14 shrinks from a thickness of 10 μm to a thickness of 0.1 μm, for example. At this time, the plurality of fine through holes 14 a described above are formed in the upper electrode 14.

  Referring again to FIG. 3, the electron emission device 10 further includes a transparent plate 15, a collector electrode 16, a phosphor 17 and a housing member 18.

  The transparent plate 15 is a thin plate body having an upper surface and a lower surface that are parallel to each other and having a thickness direction in a direction perpendicular to these surfaces. The shape of the transparent plate 15 in plan view is substantially the same rectangle as the electron-emitting device 10A. The transparent plate 15 is made of a transparent material (here, glass or acrylic). The transparent plate 15 is disposed above the electron-emitting device 10A (Z-axis positive direction) at a position away from the upper surface of the electron-emitting device 10A (upper surface of the upper electrode 14) by a predetermined distance. The transparent plate 15 is disposed so that the lower surface thereof is parallel to the plane (XY plane) of the upper electrode 14.

  The collector electrode 16 is made of a transparent conductive material (here, a transparent conductive film, ITO). The collector electrode 16 is formed in a film shape on the entire lower surface of the transparent plate 15. The collector electrode 16 is an electrode for forming an electric field that accelerates and attracts electrons emitted from the electron-emitting device 10A.

The phosphor 17 is formed in a film shape on the lower surface of the transparent plate 15 so as to cover the collector electrode 16. When the electrons collide, the phosphor 17 is excited by the electrons, and emits white light when transitioning from the excited state to the ground state. A typical example of such a white phosphor is Y ₂ O ₂ S: Tb. The white phosphor may be formed by mixing three kinds of phosphors that respectively generate red, green, and blue light at an appropriate ratio. The light generated by the phosphor 17 travels upward through the collector electrode 16 and the transparent plate 15 and enters a liquid crystal display (not shown).

The sealing member 18 is a container that forms a sealed space that houses the electron-emitting device 10 </ b> A, the transparent plate 15, the collector electrode 16, and the phosphor 17. The sealed space is maintained in a substantially vacuum state (for example, preferably 10 ² to 10 ⁻⁶ Pa, more preferably 10 ⁻³ to 10 ⁻⁵ Pa).

  The drive voltage application unit 20 applies the drive voltage Vin between the lower electrode 12 and the upper electrode 14. The drive voltage Vin becomes a voltage (the negative maximum applied voltage) Vm that makes the potential of the upper electrode 14 lower than the potential of the lower electrode 12 for a predetermined time, and then the potential of the upper electrode 14 and the potential of the lower electrode 12 are Is a voltage that repeats a pulsed voltage that becomes a voltage (the positive maximum applied voltage) Vp that makes the potential of the upper electrode 14 higher than the potential of the lower electrode 12 by a predetermined time through a voltage that equalizes.

  The bias power supply 30 includes a DC constant voltage power supply 31 and a resistor 32. The DC constant voltage power supply 31 applies a positive predetermined voltage Vc to the collector electrode 16 via a resistor 32. Thereby, the collector electrode 16 forms an electric field for accelerating and attracting electrons emitted from the electron-emitting device 10A, and captures the electrons emitted from the electron-emitting device 10A.

(Principle and operation of electron emission)
Next, the operation principle regarding the electron emission of the electron emission apparatus 10 configured as described above will be described. FIG. 6 is a voltage-polarization characteristic line showing the relationship between the voltage applied to the electron-emitting device (the device voltage that is the actual potential difference between the upper and lower electrodes) and the amount of charge appearing between the upper and lower electrodes of the electron-emitting device. FIG.

  First, it is assumed that the electron-emitting device is in a state surrounded by a broken line S0 in FIG. At this time, as shown in FIG. 7, all the electrons in the emitter section 13 are emitted, and no electrons are accumulated in the emitter section 13. That is, the upper part of the emitter section 13 is not charged. The negative pole side of the dipole DP of the emitter section 13 is in a state facing the upper surface of the emitter section 13 (Z-axis positive direction, that is, the upper electrode 14 side).

  In this state, when the drive voltage Vin is set to a predetermined negative voltage Vm so that the potential of the upper electrode 14 is lower than the potential of the lower electrode 12, the charge amount Q gradually decreases. When the actual element voltage Vka (the potential of the upper electrode 14 based on the potential of the lower electrode 12 and the applied voltage V in FIG. 6) becomes a voltage in the vicinity of the negative coercive field voltage, FIG. As shown in FIG. 4, the direction of the dipole DP of the emitter section 13 starts to reverse. That is, polarization reversal (negative side polarization reversal) starts. This state is a state of a region surrounded by a broken line S1-1 in FIG.

  By this negative side polarization reversal, contact points (triple junction) and / or fine through-holes 14a between the upper surface of the emitter section 13, the upper electrode 14, and the surrounding medium (in this case, vacuum) are formed. The electric field increases at the tip of the upper electrode 14 (electric field concentration occurs), and electrons begin to be supplied from the upper electrode 14 toward the emitter section 13 as shown in FIG. The supplied electrons are mainly in the upper part of the emitter portion 13, in the vicinity of the portion exposed from the fine through hole 14 a of the upper electrode 14, and in the vicinity of the end portion of the upper electrode 14 forming the fine through hole 14 a ( Hereinafter, it is simply accumulated in the “near the fine through-hole 14a”). This state is a state of an area surrounded by a broken line S1-2 in FIG. Thereafter, when the negative side polarization reversal is completed, the element voltage Vka rapidly changes toward the negative predetermined voltage Vm. As a result, the accumulation of electrons is completed (the electron accumulation saturation state is reached).

  In this state, when the drive voltage Vin is set to a positive predetermined voltage Vp so that the potential of the upper electrode 14 is higher than the potential of the lower electrode 12, the charge amount Q starts to gradually increase. Then, until the element voltage Vka (applied voltage V) reaches a voltage slightly smaller than the positive coercive electric field voltage, the charged state of the emitter section 13 is maintained as shown in FIG. This state is a state of a region surrounded by a broken line S2 in FIG.

  Thereafter, the element voltage Vka reaches a voltage in the vicinity of the positive coercive electric field voltage. As a result, as shown in FIG. 11, the negative electrode side of the dipole DP starts to face the upper surface side of the emitter section 13. That is, the polarization is reversed again (positive-side polarization reversal starts). This state is a state of an area surrounded by a broken line S3-1 in FIG.

  Thereafter, when positive side polarization reversal occurs continuously, the number of dipoles DP whose negative side is reversed to the upper surface side of the emitter section 13 increases. As a result, as shown in FIG. 12, the electrons accumulated in the vicinity of the fine through hole 14a receive the Coulomb repulsive force from the dipole DP and are emitted upward (Z-axis positive direction) through the fine through hole 14a. Is done. This state is a state of an area surrounded by a broken line S3-2 in FIG.

  Thereafter, the electron emission is completed, and the element voltage Vka reaches the voltage Vp. As a result, the state of the emitter section 13 returns to the initial state shown in FIG. The above is a series of operating principles (one electron emission cycle) related to the accumulation and emission of electrons. As described above, the electron-emitting device generates a large amount of electrons in one pulse in one electron emission cycle.

(Various dielectrics and amount of emitted electrons)
Hereinafter, various experimental results performed using dielectrics having different characteristics for the emitter section 13 will be described.

<Comparison between ferroelectric material and electrostrictive material>
The voltage-polarization characteristic diagram shown in FIG. 1 is a measurement result of the electron-emitting device (sample 1) provided with the dielectric 13 made of a ferroelectric material. In this case, the measurement was performed at room temperature (25 ° C.). Sample 1 is made of the above-described ternary material PMN-PT-PZ. The inventor conducted a similar experiment on the electron-emitting device (sample 2) provided with the dielectric 13 made of an electrostrictive material, and obtained the result shown in FIG. Sample 2 is made of a two-component material PMN-PT. Further, an experiment (measurement) method for obtaining a “voltage-polarization characteristic diagram” in this specification will be described later.

About these sample 1 and sample 2, the result of measuring the amount of emitted electrons, the ratio Pr / P of the remanent polarization amount Pr to the total polarization amount P, and the ratio ΔP / P of the negative polarity decrease amount ΔP to the total polarization amount P Is shown in Table 1.

  From Table 1, the amount of emitted electrons when the emitter portion 13 is made of a ferroelectric material (sample 1) is much higher than the amount of emitted electrons when the emitter portion 13 is made of an electrostrictive material (sample 2). It is understood that it is big. Further, comparing FIG. 1 with FIG. 13, it can be understood that the charge amount change rate at the time of positive side polarization reversal of sample 1 is larger than the charge amount change rate at the time of positive side polarization reversal of sample 2. At this time, the ratio Pr / P of sample 1 was 0.7 or more, and the ratio Pr / P of sample 2 was smaller than 0.7. Further, the ratio ΔP / P of Sample 1 was 0.1 or less, and the ratio ΔP / P of Sample 2 was larger than 0.1.

<Results of heating experiments on ferroelectric materials>
Next, a description will be given of experimental results obtained by changing the temperature (element temperature) of the emitter section 13 for the sample 1 (electron emitting element using a ferroelectric material for the emitter section 13). The Curie temperature Tc of this ferroelectric material is 150 ° C. In this experiment, the electron emitters heated to 75 ° C., 100 ° C., 140 ° C., and 150 ° C. are called sample 3, sample 4, sample 5, and sample 6 for convenience. . Note that the heating was performed for a sufficient time after placing the vacuum vessel in which the electron-emitting device was placed inside the thermostat. The experimental element temperature is the surface temperature of the vacuum vessel in which the element is placed.

  The voltage-polarization characteristic diagram when the element temperature is room temperature (sample 1) is as shown in FIG. On the other hand, voltage-polarization characteristic diagrams of Samples 3 to 6 are shown in FIGS.

For these samples (Sample 1 and Samples 3 to 6), the amount of emitted electrons, the ratio Pr / P of the residual polarization quantity Pr to the total polarization quantity P, and the ratio ΔP / of the negative polarity polarization reduction quantity ΔP to the total polarization quantity P The results measured for P are shown in Table 2.

  FIG. 18 is a graph illustrating the amount of emitted electrons with respect to the ratio Pr / P based on Table 2. From FIG. 18, it is understood that the amount of emitted electrons is remarkably increased in the region where the ratio Pr / P is 0.7 or more.

  FIG. 19 is a graph illustrating the amount of emitted electrons with respect to the ratio ΔP / P based on Table 2. From FIG. 19, it is understood that the amount of emitted electrons is remarkably increased in the region where the ratio ΔP / P is 0.1 or less.

<Experimental results on dielectric materials with different Curie temperatures>
Next, a plurality of electron-emitting devices (samples 7 to 12) including dielectric materials having different Curie temperatures Tc were prepared, and similar experiments were performed at room temperature. The Curie temperature of each sample is as shown in FIGS. Samples 7 to 12 are each made of a two-component material PMN-PT.

For these samples (samples 7 to 12), the amount of emitted electrons, the ratio Pr / P of the residual polarization quantity Pr to the total polarization quantity P, and the ratio ΔP / P of the negative polarity polarization reduction quantity ΔP to the total polarization quantity P are measured. The results are shown in Table 3.

  FIG. 26 is a graph illustrating the amount of emitted electrons with respect to the ratio Pr / P based on Table 3. FIG. 27 is a graph illustrating the amount of emitted electrons with respect to the ratio ΔP / P based on Table 3. From Table 3, FIG. 26 and FIG. 27, it can be understood that the amount of emitted electrons of the samples 10 to 12 having a high Curie temperature Tc is much larger than the amount of electrons emitted from the samples 7 to 9 having a low Curie temperature Tc. At this time, the ratio Pr / P of samples 10 to 12 was 0.3 or more, and the ratio ΔP / P was 0.1 or less. On the other hand, the ratio Pr / P of samples 7 to 9 was smaller than 0.3, and the ratio ΔP / P was larger than 0.1.

(Experiment (measurement) method to obtain a "voltage-polarization characteristic diagram")
Finally, the measurement method performed to obtain each of the above “voltage-polarization characteristic diagrams” (therefore, the amount of emitted electrons, the total polarization amount P, the residual polarization amount Pr, the negative polarization decrease amount ΔP, etc.) will be briefly described. . FIG. 28 is a circuit diagram used for this measurement.

  The amount of emitted electrons is obtained by measuring the current Ie caused by the electrons reaching the collector electrode 16 using the ammeter 30a and integrating the current Ie with respect to one electron emission cycle. Further, in the voltage-polarization characteristic diagram, the current Idrive flowing between the upper electrode 14 and the lower electrode 12 is measured by an ammeter 20a, and the potential difference (applied voltage) between the upper electrode 14 and the lower electrode 12 at that time. The integral value of the current Idrive measured with respect to Vdrive is obtained by plotting on the graph. From the voltage-polarization characteristic diagram, a total polarization amount P, a remanent polarization amount Pr, a negative polarity decrease amount ΔP, and the like are obtained.

(Summary)
As described above, regarding the ratio Pr / P of the remanent polarization amount Pr to the total polarization amount P of the electron-emitting device, if the ratio Pr / P is at least 0.7 or more, a very large amount of emitted electrons is obtained. It is understood that it is obtained. In addition, regarding the ratio ΔP / P of the negative polarization reduction amount ΔP to the total polarization amount P, it is understood that a very large amount of emitted electrons can be obtained if the ratio ΔP / P is 0.1 or less. The reason for this is as described in the above estimation reasons 1 and 2 (a large ratio Pr / P is effectively equivalent to a small ratio ΔP / P). Therefore, according to the present invention, an electron-emitting device capable of emitting more electrons with less power consumption is provided.

It is a voltage-polarization characteristic diagram of the electron-emitting device (sample 1) which concerns on embodiment of this invention. It is a schematic sectional drawing of the electron-emitting element for demonstrating the presumed reason for the amount of emitted electrons increasing. It is a block diagram of the apparatus with which the electron-emitting device which showed the characteristic in FIG. 1 was applied. FIG. 4 is an enlarged partial cross-sectional view of the electron-emitting device shown in FIG. FIG. 4 is an enlarged partial plan view of the upper electrode shown in FIG. 3. It is a voltage-polarization characteristic diagram for demonstrating the action | operation of an electron emission element. It is the figure which showed one state of the electron emission element. It is the figure which showed another one state of the electron emission element. It is the figure which showed another one state of the electron emission element. It is the figure which showed another one state of the electron emission element. It is the figure which showed another one state of the electron emission element. It is the figure which showed another one state of the electron emission element. It is a voltage-polarization characteristic diagram of an electron-emitting device (sample 2). It is a voltage-polarization characteristic diagram of an electron-emitting device (sample 3). It is a voltage-polarization characteristic diagram of an electron-emitting device (sample 4). It is a voltage-polarization characteristic diagram of an electron-emitting device (sample 5). It is a voltage-polarization characteristic diagram of an electron-emitting device (sample 6). It is the graph which showed the amount of emitted electrons with respect to ratio Pr / P of sample 1 and samples 3-6. It is the graph which showed the amount of emitted electrons with respect to ratio (DELTA) P / P of sample 1 and samples 3-6. It is a voltage-polarization characteristic diagram of an electron-emitting device (sample 7). It is a voltage-polarization characteristic diagram of an electron-emitting device (sample 8). It is a voltage-polarization characteristic diagram of an electron-emitting device (sample 9). It is a voltage-polarization characteristic diagram of an electron-emitting device (sample 10). It is a voltage-polarization characteristic diagram of an electron-emitting device (sample 11). It is a voltage-polarization characteristic diagram of an electron-emitting device (sample 12). It is the graph which showed the amount of emitted electrons with respect to ratio Pr / P of samples 7-12. It is the graph which showed the amount of emitted electrons with respect to ratio (DELTA) P / P of samples 7-12. It is a circuit diagram for demonstrating the measuring method for obtaining a voltage-polarization characteristic diagram.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Electron emission apparatus, 10A ... Electron emission element, 11 ... Substrate, 12 ... Lower electrode, 13 ... Emitter part, 14 ... Upper electrode, 14a ... Fine through-hole, 15 ... Transparent plate, 16 ... Collector electrode, 17 ... Fluorescence body.

Claims (2)

An emitter part made of a dielectric, a lower electrode formed at the lower part of the emitter part, and an upper part of the emitter part so as to face the lower electrode with the emitter part sandwiched between the lower electrode. And an upper electrode formed so that a plurality of fine through-holes are formed and a surface of the fine through-hole that is opposed to the emitter part is spaced apart from the emitter part by a predetermined distance; Yes, and an electron-emitting device that emits repeatedly a plurality of electrons through the micro through holes when a predetermined drive voltage is applied between the lower electrode and the upper electrode,
A ratio Pr / P of a remanent polarization amount Pr to a total polarization amount P of the emitter section when the driving voltage is applied and the electrons are repeatedly emitted is 0.7 or more. element. An emitter part made of a dielectric, a lower electrode formed at the lower part of the emitter part, and an upper part of the emitter part so as to face the lower electrode with the emitter part sandwiched between the lower electrode. And an upper electrode formed so that a plurality of fine through-holes are formed and a surface of the fine through-hole that is opposed to the emitter part is spaced apart from the emitter part by a predetermined distance; The potential of the upper electrode is set to a potential lower than the potential of the lower electrode, then the potential of the upper electrode is set to the same potential as the potential of the lower electrode, and then the upper electrode When a drive voltage with one cycle set to a potential higher than the potential of the lower electrode is applied between the upper electrode and the lower electrode, a plurality of through the fine through holes of the upper electrode That emits a single pulse of electrons A release element,
The difference between the amount of polarization when the potential of the upper electrode is set lower than the potential of the lower electrode and the amount of residual polarization when the potential of the upper electrode is set to the same potential as the potential of the lower electrode Is defined as the negative polarization reduction amount ΔP, the ratio of the negative polarization reduction amount ΔP to the total polarization amount P in the one cycle when the driving voltage is applied and the electrons are repeatedly emitted. An electron-emitting device, wherein ΔP / P is 0.1 or less.

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