JP4504655B2 - Electron emission device, drive device and display - Google Patents

Description

  The present invention relates to an electron emission device, an electron emission panel, a driving device, and a display, and more particularly to an electron emission device, a driving device, and a display that have uniform electron emission characteristics and display an image with high definition. .

  A conventional electron emission device includes an electron emission unit that emits electrons when a predetermined voltage is applied, and a resistor unit that is connected in series to the electron emission unit to prevent the occurrence of overcurrent. The electron emission part includes a Spindt type emitter, an MIS (Metal-Insulator-Semiconductor) type emitter, an MIM (Metal-Insulator-Metal) type emitter, or an emitter using a CNT (Carbon Nano Tube). (For example, Patent Document 1). These emitters are manufactured by an ultra thin film forming technique and an ultra fine processing technique.

In addition, a display using the electron emission device as described above includes a plurality of electron emission units for each pixel, the electrons emitted by the electron emission unit are accelerated by the anode voltage, and the accelerated electrons are applied to the phosphor. By being incident, the phosphor emits fluorescence, and an image is displayed.
Japanese Patent Laid-Open No. 2000-100371

  However, in such a conventional electron emission device, even when a plurality of electron emission devices are manufactured in the same manufacturing process by the ultra thin film formation technology and the ultrafine processing technology, the electron emission characteristics vary. For this reason, even when the same voltage is applied to each electron emission portion, the number of electrons emitted by each electron emission device varies. That is, the conventional electron emission device has a problem that the number of emitted electrons cannot be made uniform. In addition, in a display using a plurality of conventional electron emission portions, the number of electrons emitted between the electron emission portions cannot be made uniform, and the number of electron emission portions per pixel can be reduced. Since the electron emission characteristic per pixel is averaged at most, there is a problem that an image cannot be displayed with high definition.

  The present invention has been made to solve such a problem, and even when the electron emission characteristics of the electron emission portion are different, the number of electrons emitted per unit time can be made uniform. A radiation device, a driving device, and a display are provided.

An electron emission device according to claim 1 of the present invention is connected in series to an electron emission means having one or more electron emission portions for emitting electrons when an applied voltage equal to or higher than a threshold is applied, and the electron emission means. a capacitor portion for storing charges of the cathode current generated when the electron emitting means emits the electron, a charge-emitting circuit section for discharging charge accumulated in the capacitor section, the charge in the capacitor section Timing pulse applying means for applying a timing pulse indicating the start of charge accumulation and the start of discharge of charge to the capacitor section and the charge discharge circuit section, and the electron emission means together with the start of charge accumulation in the capacitor section The emission of the electrons starts, and the applied voltage decreases according to the accumulation of the electric charge in the capacitor unit, and the threshold value is exceeded. It has a configuration in which stop the emission of the electrons when they become fence.

With this configuration, since the number of electrons emitted per unit time from the electron emission means is controlled by the capacitor unit , the number of electrons emitted per unit time can be reduced without depending on the electron emission characteristics of the electron emission means. It can be made uniform.

Further, this configuration, it is possible to release the charge accumulated in the capacitor unit in each unit time, it can be returned to the initial state capacitor portion per unit time.

A driving apparatus according to claim 2 of the present invention is a driving apparatus for driving an electron emission panel in which a plurality of electron emission means according to claim 1 are arranged in a matrix, wherein the plurality of electron emission means The capacitor unit and the charge emission circuit unit are connected to each other, and the timing pulse application unit applies the timing pulse to the capacitor unit and the charge emission circuit unit connected to each of the plurality of electron emission units. It has the composition which is.

  With this configuration, it is possible to provide a driving device that can make the number of electrons emitted per unit time uniform by each electron emission means without depending on the electron emission characteristics of each electron emission means.

Further, this configuration, it is possible to release the charge accumulated in the capacitor unit in each unit time, it can be returned to the initial state capacitor portion per unit time.

According to a third aspect of the present invention, there is provided a display comprising: the driving device according to the second aspect; and a phosphor panel that emits fluorescence when electrons emitted from the electron emission panel are incident. Have.

  With this configuration, the number of electrons emitted per unit time is controlled to be uniform by one electron emitting means, so that the brightness of the fluorescence emitted by the electrons emitted by one electron emitting means is made uniform. can do. For this reason, the number of electron emission portions per pixel can be reduced, and an image can be displayed with high definition.

The present invention, even when the electron emission characteristic of the electron emission portion are different, electron emission devices can be made uniform the number of electrons emitted from the electron emitting means per unit time, the driving device and a display It can be provided.

  Embodiments of the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, an electron emission apparatus 1000 according to the present invention includes an electron emission means 1100 having an electron emission section 1110 that emits electrons when a voltage higher than a threshold is applied, and the electron emission means 1100 emits electrons. And an electron number detecting means 1200 for detecting the number of electrons emitted by the electron emitting means 1100 by time-integrating the cathode current value of the cathode current generated. In FIG. 1, the electron emitter 1110 is shown as an equivalent circuit.

  The electron emission device 1000 is connected to an external power supply 100, and the external power supply 100 is connected to the electron emission means 1100 via a gate voltage application means 110 that applies a gate voltage to the electron emission means 1100 and an electron number detection means 1200. Cathode voltage applying means 120 for applying a cathode voltage and timing pulse applying means 130 for applying a timing pulse to be described later to the electron number detecting means 1200 are provided.

  Here, the cathode current refers to a current that flows between the electron emission means 1100 and the cathode voltage application means 120 via the electron number detection means 1200.

The electron emission means 1100 has a gate side terminal 1100 a electrically connected to the external power source 100 and a cathode side terminal 1100 b electrically connected to the electron number detection means 1200. In the following description, the threshold value of the voltage at which the electron emitting means 1100 emits electrons is expressed as V _th (V).

  The electron emitting means 1100 is a conventional Spindt emitter, MIS emitter, MIM emitter, surface conduction emitter (SCE), DLC (Diamond Like Carbon) or CNT. If it is comprised by the used emitter etc. and it is a conventional emitter, the structure will not be limited. In the case of a Spindt-type emitter, it goes without saying that a refractory metal material such as niobium, tungsten or molybdenum, a semiconductor material such as silicon, or the like is used as the tip material.

The electron number detecting means 1200 controls the electron emitting means 1100 to stop emitting electrons when the number of electrons emitted by the electron emitting means 1100 reaches a preset value. Note that the number of electrons detecting means 1200 is such that when the number of electrons emitted by the electron emitting means 1100 reaches a preset value, the value of the voltage applied to the electron emitting means 1100 becomes V _th or less. The electron emission means 1100 is controlled so as to stop the emission of electrons.

  Here, a configuration example of the electron number detection unit 1200 will be described.

  The electron number detection means 1200 is connected in series with the electron emission means 1100, and stores a capacitor unit 1210 that accumulates electric charge according to the cathode current, and a data voltage application circuit unit 1220 for applying a cathode voltage to the electron emission means 1100. And a charge discharge circuit unit 1230 for discharging the charge accumulated in the capacitor unit 1210. Note that the timing of cathode voltage application by the data voltage application circuit unit 1220 and the timing of charge emission by the charge emission circuit unit 1230 are controlled by timing pulses. In other words, the timing pulse refers to a pulse voltage for controlling the timing at which the cathode voltage is applied to the electron emission means 1100 and further for controlling the timing of charge emission.

  The data voltage application circuit unit 1220 includes a first transistor 1221, a fixed power source 1222, and a second transistor 1223. In addition, the charge discharge circuit portion 1230 includes a resistor 1231, an inverter 1232, and a third transistor 1233. Note that the first transistor 1221, the second transistor 1223, and the third transistor 1233 are each configured by a field effect transistor (FET).

  The capacitor unit 1210 has a first capacitor terminal 1210a electrically connected to the cathode side terminal 1100b and a second capacitor terminal 1210b connected to the data voltage application circuit unit 1220.

The first transistor 1221 is turned off when a voltage of −V _C (V) is applied to the gate terminal, and a voltage of V _GS −V _C (V) is applied to the gate terminal. In addition, it is turned on. Note that the first transistor 1221 has a source terminal electrically connected to the cathode voltage application unit 120, a drain terminal electrically connected to the second capacitor terminal 1210b, and a gate terminal connected to the negative electrode of the fixed power source 1222. Electrically connected.

The fixed power source 1222 is configured to generate an electromotive force of V _C −V _GS (V). Note that the fixed power source 1222 has a positive electrode electrically connected to the timing pulse applying unit 130 and a negative electrode electrically connected to the gate terminal of the first transistor 1221.

The second transistor 1223 is turned off when a voltage of 0 (V) is applied to the gate terminal, and is turned on when a voltage of −V _GS (V) is applied to the gate terminal. It is supposed to become. Note that the second transistor 1223 has a drain terminal electrically connected to the second capacitor terminal 1210b, a source terminal grounded, and a gate terminal electrically connected to the timing pulse applying unit 130.

  The resistor 1231 has one terminal electrically connected to the first capacitor terminal 1210 a and one terminal electrically connected to the drain terminal of the third transistor 1233.

  The inverter 1232 inverts the sign of the voltage value of the timing pulse applied by the timing pulse applying unit 130 and applies the timing pulse with the inverted sign of the voltage value to the gate terminal of the third transistor 1233. ing.

The third transistor 1233 is turned off when a voltage of 0 (V) is applied to the gate terminal, and turned on when a voltage of V _GS (V) is applied. It has become. Note that the third transistor 1233 has a drain terminal electrically connected to the resistor 1231, a source terminal grounded, and a gate terminal electrically connected to the inverter 1232.

Here, the above-described ON state refers to a state in which a current can flow when a voltage is applied between the source terminal and the drain terminal, and the above-described OFF state refers to the source terminal and the drain terminal. Even when a voltage is applied between the two, a current cannot flow. The voltage value V _GS described above is smaller than the voltage value V _C described above.

  Hereinafter, the operation of the electron emission apparatus 1000 according to the embodiment of the present invention will be described with reference to the block diagram of FIG. 1 and the timing chart of FIG.

In the following description, V _FET1 refers to a voltage applied to the gate terminal of the first transistor 1221, and V _FET2 refers to a voltage applied to the gate terminal of the second transistor 1223. , V _FET3 refers to a voltage applied to the gate terminal of the third transistor 1233. In _addition, the _{I Cap,} the current flowing through the capacitor 1210, namely refers to the current value of the cathodic current, and _{V E,} the absolute value of the potential difference between the gate-side terminal 1100a and a cathode-side terminal 1100b V _Cap is an absolute value of a potential difference between the first capacitor terminal 1210a and the second capacitor terminal 1210b.

First, at time T ₁ , a gate voltage having a voltage value V _G (V) and a cathode voltage having a voltage value −V _C (V) are applied to the electron emission device 1000. Also, at time _{T 1,} the voltage value of the timing pulses consists _-V GS (V) to 0 _(V), V _FET1 becomes _{-V C + V GS (V)} , the first transistor 1221 is turned on It is. For this reason, V _E becomes V _G + V _C (V), and electrons are emitted by the electron emission means 1100. At this time, I _Cap is I ₁ (A).

Next, between time T ₁ and time T ₂ , charges are accumulated in the capacitor unit 1210 due to the cathode current flowing through the capacitor unit 1210, V _Cap increases, and V _E decreases as V _Cap increases. When V _E becomes smaller than V _th (V), that is, when V _Cap becomes larger than V _G + V _C −V _th (V) (time T ₂ ), the electron emission means 1100 As the electron emission is stopped, I _Cap becomes 0 (A), and the increase in V _Cap and the decrease in V _E are stopped. Then, the parameters are not changed between the time T _2, the time T _3.

After that, at time T ₃ , a timing pulse having a voltage value of −V _GS (V) is applied to the fixed power source 1222, the second transistor 1223, and the inverter 1232 by the timing pulse applying unit 130, whereby V _FET1 , Since V _FET2 and V _FET3 become −V _C (V), −V _GS (V), and V _GS (V), respectively, the first transistor 1221, the second transistor 1223, and the third transistor 1233 Are an off state, an on state, and an on state, respectively. As a result, V _E becomes V _G (V). Further, the electric charge accumulated in the capacitor unit 1210 is released, and V _Cap gradually decreases from V _G + V _C −V _th (V) to 0 (V) between time T ₃ and time T _4. .

Here, a difference in operation between the three electron emission devices A, B, and C having different electron emission characteristics at time T ₁ will be described with reference to the timing chart of FIG. It is assumed that V _th of the electron emission means 1100 of each electron emission device is equal. In addition, the capacitances of the capacitor units 1210 of the respective electron emission devices are assumed to be equal. In FIG. 3, I _1A , I _1B and I _1C refer to I _{Cap at} time T ₁ of the electron emission devices A, B and C. In FIG. 3, time T _2A , time T _2B, and time T _{2C mean that} the value of V _Cap of the capacitor unit 1210 of the electron emission devices A, B, and C is V _G + V _C −V _th (V). This is the time when

It can be assumed that the current value I _Cap of the cathode current generated when electrons are emitted from each electron emission means 1100 is proportional to the number of electrons emitted by each electron emission device per minute unit time. The amount of charge accumulated in the capacitor unit 1210 of each electron emission device in accordance with the cathode current is obtained by integrating the time I _Cap from time T ₁ to time T _2A , T _2B or T _2C. Can be considered equal. Here, in any capacitor unit 1210 of the electron emission device, V _{Cap at} time T ₂ is V _G + V _C −V _th (V), and thus the amount of charge accumulated in the capacitor unit 1210 of each electron emission device is Naturally, they will be equal.

That is, when V _Cap increases from 0 (V) to V _G + V _C −V _th (V), the number of electrons emitted by each electron emission device is different when I _{Cap at} time T ₁ is different. Even if they are, they are equal. For this reason, when the time from the time when electrons are emitted until the timing pulse is applied, that is, when the time from time T ₁ to time T ₃ is considered as one unit time, the number of electrons emitted per unit time is It can be made uniform.

  In the above description, the example in which the electron emission means 1100 is configured by one electron emission unit 1110 has been described. Can be implemented. By constituting the electron emitting means 1100 with a plurality of n electron emitting portions 1110a to 1110n, the cathode current from the electron emitting means 1100 can be increased as compared with the case where it is constituted by one electron emitting portion 1110.

  As described above, in the electron emission device according to the embodiment of the present invention, since the number of electrons emitted from the electron emission means per unit time is controlled by the electron number detection means, the electron emission characteristics of the electron emission means The number of electrons emitted per unit time can be made uniform without depending on.

  Next, the display 2000 according to the embodiment of the present invention will be described.

  In FIG. 5, the display 2000 of the present invention includes an electron emission panel 2100, a driving device 2200, and a phosphor panel 2300.

The electron emission panel 2100 includes a plurality of electron emission means 2110. Each electron emitting means 2110 is arranged in a matrix, and emits electrons when a voltage is applied. Note that V _th of each electron emitting means 2110 is assumed to be equal.

  The electron emission means 2110 is configured by one electron emission part 2111 shown in an equivalent circuit in FIG. 6A or a plurality of n electron emission parts 211a to 211n as shown in FIG. 6B. Yes.

  For example, as shown in FIG. 7, the electron emission panel 2100 includes a plurality of scanning lines and a plurality of cathodes for applying a voltage to each electron emission means 2110. Each scanning line is arranged so as to be orthogonal to each cathode. Note that each of the scanning line and the cathode includes an electrical wiring.

  Each electron emitting means 2110 is arranged in a region where each scanning line and each cathode intersect to form a pixel. Each electron emitting means 2110 has four electron emitting portions 2111. The number of electron emitting portions 2111 is not limited to four, and may be one or more.

  The driving device 2200 sequentially applies a pulse voltage to each of a plurality of scanning lines and each cathode based on a video signal input from the outside, and drives each electron emission means 2110 in a matrix manner. The pulse voltage applied to the scan line refers to the gate voltage described above, and the pulse voltage applied to the cathode refers to the cathode voltage described above.

  Here, a more detailed configuration of the driving device 2200 will be described. The driving device 2200 includes a plurality of electron number detecting means 2210 electrically connected to the cathodes, a gate voltage applying means 2220 for sequentially applying a gate voltage to each scanning line based on a video signal input from the outside, Cathode voltage application means 2230 for sequentially applying a cathode voltage to each cathode via each electron number detection means 2210 based on an externally input video signal, and timing pulse application for applying a timing pulse to each electron number detection means 2210 Means 2240 and anode voltage application means 2250 for applying an anode voltage for accelerating electrons emitted by the electron emission panel 2100 to the transparent electrode of the phosphor panel 2300 are provided.

  Each electron number detection means 2210 is configured in the same manner as the electron number detection means 1200 described above, and includes a capacitor section, a data voltage application circuit section, and a charge emission circuit section. Assume that the capacitances of the capacitor portions of the respective electron number detection means 2210 are equal. In addition, the data voltage application circuit unit and the charge discharge circuit unit of each electron number detection unit 2210 operate according to the timing pulse applied by the timing pulse application unit 2240 so as to discharge the charge accumulated in the capacitor unit. It has become. The timing pulse applying means 2240 applies a timing pulse similar to the timing pulse applying means 130 described above to the data voltage applying circuit portion and the charge discharging circuit portion of each electron number detecting means 2210.

  The phosphor panel 2300 is installed to face the electron emission panel 2100 with a gap maintained in a vacuum. The phosphor panel 2300 includes a transparent electrode (not shown) and a phosphor, and an anode voltage for accelerating the electrons radiated by the respective electron emission means 2110 is applied to the transparent electrode by the driving device 2200. It has come to be. In addition, electrons emitted by the respective electron emission means 2110 of the electron emission panel 2100 and accelerated by the anode voltage are incident on the phosphor, and the phosphor has a predetermined shape when the electrons are incident. It emits fluorescence at a wavelength.

  Hereinafter, the operation of the display 2000 according to the embodiment of the present invention will be described. In FIG. 7, a case where a pixel at the intersection of the cathode B and the scanning line A emits light will be described as an example. The electron emitting means 2110 that forms this pixel is referred to as an electron emitting means 2110X.

  First, when the pixel at the intersection of the cathode B and the scanning line A is caused to emit light in accordance with a video signal input from the outside, the cathode voltage applied to the cathode B connected to the electron emission means 2110X at the pixel position. And a gate voltage is applied to the scanning line A.

  Then, electrons are emitted by the electron emitting means 2110X, and the emitted electrons are accelerated by the anode voltage applied to the phosphor panel 2300 by the anode voltage applying means 2250 and are incident on the phosphor panel 2300. Fluorescence is emitted. At this time, the number of electrons emitted per unit time by the electron emission means 2110X is controlled by the electron number detection means 2210 as described above.

  Similarly, in other electron emitting means 2110, electrons are emitted when a gate voltage and a cathode voltage are applied in accordance with a video signal input from the outside. At this time, since the number of electron detectors 2210 are controlled so that the number of electrons emitted by each electron emitter 2110 per unit time is equal, the luminance of the fluorescence emitted by the phosphor per unit time. Are equal.

  In the above description, the number of times the timing pulse is applied by the timing pulse applying means 2240 is set to one time within the time when the gate voltage and the cathode voltage are applied to one electron emitting means 2110. The display 2000 is capable of displaying a binary image with uniform luminance. In addition, the display 2000 can display the time by setting the number of times that the timing pulse is applied by the timing pulse applying means 2240 to a plurality of times within the time when the gate voltage and the cathode voltage are applied to one electron emitting means 2110. Divided gradation display can be performed.

  As described above, the display 2000 according to the embodiment of the present invention has a configuration in which the electron number detection unit 2210 controls the number of electrons per pixel, and thus the electron emission unit 2110 of the electron emission unit 2110 has the configuration. Regardless of the number, variation in current between pixels can be reduced, and fluorescence brightness can be made uniform.

  Therefore, in the display 2000 according to the embodiment of the present invention, even when the electron emission means 2110 is constituted by the plurality of electron emission parts 2111, the electron emission means 2110 can be constituted by a smaller number of electron emission parts 2111 than in the prior art. Therefore, it is possible to achieve higher definition than the conventional phosphor panel.

It is a block diagram of the electron emission apparatus of embodiment of this invention. It is a timing chart which shows the flow of operation | movement which concerns on the electron emission apparatus of embodiment of this invention. It is a timing chart which shows the difference in operation | movement of the electron emission apparatus from which electron emission characteristics differ. It is a figure which shows an example in which the electron emission means was comprised by the several electron emission part. It is a block diagram of a display of an embodiment of the invention. (A) It is a figure which shows the structural example of the electron emission means by one electron emission part. (B) It is a figure which shows the structural example of the electron emission means by several electron emission part. It is a top view of the electron emission panel of embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 External power supply 110, 2220 Gate voltage application means 120, 2230 Cathode voltage application means 130, 2240 Timing pulse application means 1000 Electron emission device 1100, 2110 Electron emission means 1100a Gate side terminal 1100b Cathode side terminal 1110 (a to n), 2111 (A to n), electron emission unit 1200, 2210 electron number detection means 1210 capacitor unit 1210a first capacitor terminal 1210b second capacitor terminal 1220 data voltage application circuit unit 1221 first transistor 1222 fixed power supply 1223 second transistor 1230 Charge Emission Circuit Unit 1231 Resistor 1232 Inverter 1233 Third Transistor 2000 Display 2100 Electron Emission Panel 2200 Driver 2250 Anode Voltage Application Unit 23 0 phosphor panel

Claims (3)

An electron emission unit having an electron emission portion which emits electrons more than one when the threshold or more of the applied voltage is applied, generated when said electron emitting means are connected in series to emit the electrons to said electron emitting means A capacitor unit for accumulating the charge of the cathode current , a charge emission circuit unit for discharging the charge accumulated in the capacitor unit, and a timing pulse indicating the start of accumulation of the charge and the start of discharge of the charge in the capacitor unit And a timing pulse applying means for applying to the capacitor part and the charge discharging circuit part,
The electron emission means starts emission of the electrons together with the start of accumulation of the charge in the capacitor unit, and the applied voltage decreases according to the accumulation of the charge in the capacitor unit and becomes smaller than the threshold value. An electron emission device for stopping emission of electrons. A driving apparatus for driving an electron emission panel in which a plurality of electron emission means according to claim 1 are arranged in a matrix,
The capacitor unit and the charge emission circuit unit are connected to each of the plurality of electron emission means,
The driving device according to claim 1, wherein the timing pulse applying unit applies the timing pulse to the capacitor unit and the charge discharge circuit unit connected to each of the plurality of electron emitting units. 3. A display comprising: the driving device according to claim 2; and a phosphor panel that emits fluorescence when electrons emitted by the electron emission panel are incident thereon.

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