KR100351027B1 - Driver for field emission light-emitting devices - Google Patents

Abstract

(Problem) Provided is a driving device for a field emission light emitting device capable of increasing the anode voltage.

(Solution) When a positive bias voltage is applied with the anode selection voltage as Va ₁ and the anode non-selection voltage as Va ₂ , the potential difference between adjacent anode electrodes is lowered by the quotient of the bias voltage Va ₂ . The voltage can be increased. After the end of one frame period, a non-display period is provided until the next image is displayed. In this non-display period, the periods 1a and 2a at the GND level, for example, at which the anode voltages 1 and 2 are voltages at which secondary electrons are not emitted from the protective film 81 are inserted. As a result, it is possible to remove the charges charged on the protective film 81 and to prevent the progress of charging.

Description

DRIVER FOR FIELD EMISSION LIGHT-EMITTING DEVICES

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a driving device for a field emission type light emitting device such as a field emission display (FED).

When the applied electric field of the metal or semiconductor surface is about 10 ⁹ [volts / m], electrons pass through the barrier due to the tunnel effect, and electrons are emitted in vacuum even at room temperature. This phenomenon is called field emission. By utilizing semiconductor micromachining technology, it is possible to produce a surface emission type field emission portion composed of an array of field emission portions, and is used in field emission display devices such as FED. In addition, the application of the field emission unit to an optical print forming an image on a photosensitive film as a one-dimensional array is also considered.

In such a field emission type light emitting device for an optical print head for a display device, high luminance is one problem. This is because the luminous efficiency of the conventional phosphor is not good at low anode voltage. In a two-electrode full color FED and a so-called bladder-type anode electrode structure, the anode voltage cannot be increased.

4-8, the structure and the driving method of the conventional two-electrode type FED will be described, and the reason why the anode voltage cannot be increased is explained.

4 is a schematic configuration diagram for explaining an example of a two-electrode full color FED.

In the figure, 31 is a cathode substrate, 32 is an anode substrate, 33 is a spacer, 34-1 to 34-4 is a cathode electrode, 35 is a patch-shaped gate electrode, 36-1 to 36-5 is an anode electrode, 37 Is a phosphor dot.

This color FED is an anode substrate having a cathode substrate 31 having a field emission portion formed in a two-dimensional matrix, and a phosphor dot 37 formed in a two-dimensional matrix on anode electrodes 36-1 to 36-5 opposite thereto. (32) are arranged to face each other, and the space | interval of both is uniformly supported by the spacer 33, the outer periphery of both board | substrates is sealed, and the inside was kept in the vacuum state.

On the cathode substrate 31, the cathode electrodes 34-1 to 34-5 are arranged in a stripe shape, arranged in the column direction. Although the detailed structure of the field emission unit is omitted, the image electrodes are formed on the cathode electrodes 36-1 to 36-4, and a plurality of fine cone-shaped emitters are formed thereon through the resistive layer, and the gate electrode on the patch is formed. It faces the anode substrate 32 side through the opening part of 37. As shown in FIG. The field emission portion is constituted by the cathode electrodes 34-1 to 34-4, the cone-shaped emitter, and the patch-like gate electrode. In addition, the wiring between the some gate electrode 35 is abbreviate | omitted in this figure, and is mentioned later with reference to FIG.

On the other hand, on the lower surface of the transparent anode substrate 32, transparent anode electrodes 36-1 to 36-5 are arranged in a columnar manner in a stripe shape. The above-described cathode electrodes 34-1 to 34-4 are parallel to each other in a one-to-one correspondence. Every other odd-numbered anode electrode 36-1, 36-3, 36-5, ... is connected in common at the front end, and every other even-numbered anode electrode 36-2, 36-4,... Is commonly connected at the rear end not shown. That is, the anode electrode which has two anode terminals by which every other alternately meshes is formed.

As the anode electrodes 36-1 to 36-5, a conductive transparent thin film of ITO (Indium Tin Oxide) is used, and on the lower surface thereof, each of the plurality of phosphor dots 37 having the same emission color is used as the anode electrodes 36-1 to 36 respectively. Application | coating is formed at predetermined intervals in the longitudinal direction of -5). Red (R) on the anode electrode 36-1, green (G) on the anode electrode 36-2, blue (B) on the anode electrode 36-3, red (R) on the anode electrode 36-4 In the column direction, three primary colors of phosphor dots 37 of R, G, and B are alternately arranged to form a display unit. The field emission portion having the phosphor dot 37 and the gate electrode 35 correspond one-to-one.

When a gate voltage of tens of volts is applied to a specific gate electrode 35 on the cathode substrate 31 side with respect to the cathode potential, electrons are emitted from the cone-shaped emitter and at the same time, several hundred to the anode electrode immediately above. When the anode voltage of volts is applied, electrons emitted from the emitter are rounded to the phosphor dot 37 directly above, and the phosphor dot 37 emits light. The signal voltage of the pulse width corresponding to the gradation of the image signal is applied to the cathode wiring connected to the field emission unit having the gate electrode 35 to which the gate voltage is applied, so that the amount of light emitted from the phosphor dot 37 is applied to the gradation. It is controlled to follow.

FIG. 5 is an electrode connection diagram for explaining a method of driving the two-electrode full color FED shown in FIG. 1.

In the figure, the same code | symbol is attached | subjected to the same part as FIG. 4, and description is abbreviate | omitted. 41 to 44 are gate wirings, and 45 and 46 are anode wirings. The gate electrode 35 and the phosphor dot 37 facing the gate electrode 35 are described again.

The gate wirings 41 to 44 extend in the column direction, are alternately connected to every other dot of the gate electrode 35, and the two gate terminals G1, G2, G3, G4,. , (G _n-1 , G _n ) are taken out. The anode wires 45 and 46 are connected to the pair of anode electrodes 36-1, 36-3, 36-5, ..., and (36-2, 36-4, 36-6, ...) on the bladder, The anode terminals A1 and A2 are drawn out. Although the m cathode electrodes and the cathode wirings are not shown, in FIG. 4, adjacent cathode electrodes 34-1, 34-2, (34-3, 34-4),... Each one is in contact with one cathode terminal.

The total number of gate terminals (gate wirings) is twice the number of display lines in the row direction. However, since the multiplexer can be driven by the matrix of the cathode wiring and the gate wiring, the cathode wiring is taken out as one terminal by connecting two adjacent lines to each other.

The pixel selection method of the two-electrode full color FED is performed only by the matrix of the gate wirings 41 to 44 arranged in the row direction and the cathode wiring arranged in the column direction, and one frame is performed by performing linear sequential scanning in the row direction. Displays an image.

FIG. 6 is a driving timing diagram of the two-electrode full color FED shown in FIG. 4. An example of a pixel selection method will now be described with reference to FIG. 5.

In the figure, 51 and 52 are anode voltages applied to the anode terminals A1 and A2, and 53 to 60 are gate terminals G ₁ , G ₃ , G ₅ ,..., G _n-1 , G ₂ , G ₄ , G ₆ ,..., G _2n ). Two non-illustrated cathode electrodes C _{1 to} C _m arranged in the column direction are commonly connected to one cathode terminal, and data pulses for determining the light emission amount of the phosphor dot are simultaneously applied. 61 is a data pulse applied to the cathode electrode C _m in the period in which the scan pulse is applied to the gate terminal G _2n .

In the period in which the positive anode voltage 51 is applied to the anode electrode A1 and the anode voltage 52 of the GND level (0 volt) is applied to the anode electrode A2, the odd-numbered gate terminal G is applied. Scan pulses 53 to 55 are sequentially applied to ₁ , G ₃ , G ₅ ,..., G _n-1 , and in synchronization with this, the gray level of the selected pixel is applied to each of the cathode electrodes C _{1 to} C _m . According to the data pulse of the width.

On the other hand, in the period in which the positive anode voltage 52 is applied to the anode electrode A2 and the anode voltage 51 of the GND level is applied to the anode electrode A1, the even-numbered gate terminals G ₂ and G are applied. Scan pulses 56 to ₆₀ are sequentially applied to ₄ , G ₆ , ... G _n ), and data pulses are applied to the respective cathode terminals C _{1 to} C _{m in} synchronization with this.

Since there are two gate wirings 41 to 44 per one display line, one frame of the image is divided into two subframes. By applying a positive anode voltage to one of the anode terminals A1 and A2 in synchronism with the subframe period, the anode electrodes 36-1, 36-3, 36-5, 36-2, 36- 4, 36-6) are alternately switched, so that the potentials of the anode electrodes on both sides of the selected anode electrode are always at the GND level (0 volt). As a result, a focused electric field is formed, electrons are focused on the selected phosphor dot 37, and spreading of electrons emitted from the emitter of the field emission unit can be suppressed.

With the two-electrode anode structure described above, in order to increase the anode voltage in order to obtain high brightness, the withstand voltage between the anode electrode and the gate electrode and the withstand voltage between the anode electrodes must be improved simultaneously. However, due to the structural constraint that the wiring gap between the anode electrodes is very narrow, when the anode voltage is increased, the electric field strength between the anode electrodes increases and the dielectric breakdown occurs. It is considered that this dielectric breakdown starts with the discharge between the electrodes, and when the degree of vacuum decreases due to the generation of gas, the discharge occurs between the anode electrode and the gate electrode.

Since the gap between the anode electrodes inevitably becomes narrower when the resolution of the display image is increased, the luminance improvement and the high resolution due to the high anode voltage are incompatible. In addition, since the equivalent load between the anode electrodes becomes capacitive, an inrush current flows when the anode voltage is switched to a rectangular wave. Therefore, simply raising the anode voltage is difficult not only withstand voltage but also with power consumption. In addition, depending on the inter-electrode gap, the electrode layer may be destroyed by the inrush current.

As described above, in the structure of the two-electrode full color FED, it is difficult to increase the anode voltage, and high luminance is difficult. Therefore, the present inventor has proposed a driving method in which the off level of the anode voltage is not a zero potential but a positive potential in order to increase the driving voltage of the anode without increasing the potential difference between the anode electrodes. (SOCIETY FOR INFORMATION DISPLAY INTERNATIONAL SYMPOSIUM DIGEST OF TECHNICAL PARERS VOLUME XXIX, May 17, 1998, US P. 193-196). As a result, even in the conventional structure, the driving voltage of the anode can be increased to realize high luminance.

FIG. 7 is a waveform diagram illustrating a driving apparatus of the two-electrode full color FED of FIG. In the figure, 71 and 72 are anode voltages applied to the anode terminals A1 and A2. The scan pulses applied to the gate terminals and the data pulses applied to the cathode terminals C _{1 to} C _n are the same as in FIG. 6.

When a positive bias voltage is applied with the anode selection voltage (on level) as V _a1 and the anode non-selection voltage (off level) as V _a2 , the potential difference (switching voltage) between adjacent anode electrodes is V _a1 -V and by _a2, it is lowered by a bias voltage (V _a2) quotient. This means that even if the anode voltage is increased by the quotient of the bias voltage _Va2 , the potential difference between the anode electrodes does not change from the conventional one. As a result, the anode voltage can be made higher by the bias voltage V _a2 quotient than in the related art. As a result, the luminous efficiency of the phosphor dot can be improved and the luminous luminance can be increased. By way of example to the V _a2 to 300V it can hoist the V _a1 to 800V.

Therefore, the anode voltage (V _a1) can be higher than the anode voltage resistance between the electrodes. However, since the focusing ability is lowered, there is a concern that the light emitting dots adjacent to light may be emitted. However, the decrease in the focusing speed can be compensated by the design such as narrowing the area of the field emission section.

The two-electrode full color FED described above uses switching of the anode voltage to focus the emitted electrons on the desired phosphor dot 37. Therefore, since the voltage of OFF can be taken freely, the above-mentioned driving becomes possible.

However, in the above-described proposed method, there is no new period since the period at which the anode voltage becomes the GND level (zero volts) is eliminated.

8 is a schematic cross-sectional view of the electrode type full color FED of FIG. 4 for explaining a driving problem. In the figure, the same code | symbol is attached | subjected to the same part as FIG. 4, and description is abbreviate | omitted. 81 is an insulating protective film and is covered on the anode substrate 32 between the anode electrodes 36-1 and 36-2. In other words, the protective film 81 is an insulating portion whose surface is exposed on the side of the cathode substrate 31 having the gate electrode 35 between the anode electrodes 36-1 and 36-2. Electrons emitted from the field emission section having the gate electrode 35 to which the gate voltage (+ Vg) is applied are adorned to the opposing phosphor dots 37. In that case, part of the protection film 81 is also rounded to emit secondary electrons. For this reason, the protective film 81 charges to + (charge-up). As this charging proceeds, the breakdown voltage between the anode electrodes 32-1 and 32-2 decreases.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a driving device for a field emission type light emitting device capable of increasing an anode voltage.

In the invention according to claim 1, a plurality of anode electrodes are alternately connected in common, a plurality of anode terminals are drawn out, an insulating portion is exposed on an anode substrate, and a plurality of field emission means are opposed to the plurality of anode electrodes. The anode selection voltage and the anode non-selection voltage, which is a positive voltage lower than the anode selection voltage, are alternately supplied to each of the anode terminals, so that electrons from the preselected field emission means are focused and the anode is selected. A driving device of a field emission type light emitting element for emitting phosphor dots on an electrode, the switching device comprising switching driving means for supplying the anode selection voltage and the anode non-selection voltage to each of the anode terminals in an image output period. The image ratio between the image output periods while being supplied alternately In at least a part of the output period, a voltage at which secondary electrons are not emitted from the insulator is applied.

Therefore, by applying the anode non-selection voltage in the image output period, even if the anode voltage is increased, an increase in the potential difference between the anode electrodes can be prevented, so that no dielectric breakdown occurs. Further, in at least a part of the image non-output period, by applying a voltage at which secondary electrons are not emitted from the exposed insulating portion, excessive charging of the exposed insulating portion can be suppressed, and a drop in the withstand voltage can be prevented.

In the invention according to claim 2, a plurality of anode electrodes are alternately connected in common, a plurality of anode terminals are drawn out, an insulating portion is exposed on the anode substrate, and an arrangement of a plurality of field emission means is opposed to the plurality of anode electrodes. The anode selection voltage and the anode non-selection voltage, which is a positive voltage lower than the anode selection voltage, are alternately supplied to each of the anode terminals, so that electrons from the preselected field emission means are focused and the phosphor dot on the anode electrode is collected. An apparatus for driving a field emission type light emitting element for emitting light, the apparatus comprising: switching driving means, the switching driving means alternately supplying the anode selection voltage and the anode non-selection voltage to each of the anode terminals in an image output period. An image non-output period between the image output period and In the period of at least a portion to the insulating non-emitting phosphor is a secondary electron voltage to a voltage at the same time does not release from the voltage applied portion.

Therefore, even if the anode voltage is increased by applying the anode non-selection voltage in the image output period, the rise of the potential difference between the anode electrodes can be prevented, so that no dielectric breakdown occurs. Furthermore, in at least a part of the image non-output period, by applying a voltage at which secondary electrons are not emitted from the exposed insulating portion, excessive charging of the exposed insulating portion can be suppressed, and a drop in the withstand voltage can be prevented. At the same time, light emission of the phosphor can be prevented in at least part of the above-described image non-output period.

In the invention according to claim 3, the field emission type light emitting device according to claim 1 or 2 has a gate voltage output means, and the gate voltage output means is provided at each of the anode terminals from the insulation portion. The gate pulse is applied to the gate electrode of each of the field emission means in a period during which a voltage at which the secondary electrons are not emitted is applied. Therefore, deterioration of the electron emission characteristic of the field emission means can be prevented.

In the invention according to claim 4, the field emission type light emitting device according to claim 3 has a gate voltage control means, and the gate voltage control means outputs the voltage value of the gate pulse in the image output period. It is controlled by a value different from the voltage value of the scanning pulse.

Therefore, irrespective of the electron emission amount in the image output period related to the display luminance, the electron emission amount for preventing the deterioration of the electron emission characteristic can be set to an optimum value.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a waveform diagram of a first example for explaining the driving device of the field emission type light emitting device of the present invention.

Fig. 2 is a waveform diagram of a second example for explaining the driving device of the field emission type light emitting device of the present invention.

Figure 3 is a block diagram of a driving device of the field emission type light emitting device of the present invention.

4 is a schematic configuration diagram for explaining an example of a two-electrode full color FED.

FIG. 5 is an electrode connection diagram illustrating a method of driving the two-electrode full color FED of FIG. 4. FIG.

6 is a driving timing diagram of the two-electrode full color FED of FIG. 4;

FIG. 7 is a waveform diagram illustrating the driving device of the two-electrode full color FED of FIG. 4 already proposed. FIG.

8 is a schematic cross-sectional view of the two-electrode full color FED of FIG. 4 for explaining a driving problem.

(Explanation of symbols for the main parts of the drawing)

1, 3, 51, 71... Anode voltage applied to anode terminal A1

2, 4, 52, 72... Anode voltage applied to anode terminal A2

53 to 60. Scan pulses applied to the gate terminals G ₁ , G ₃ , G ₅ ..., G _n-1 , G ₂ , G ₄ , G ₆ ,..., G _2n

81... Shield

1 is a waveform diagram of a first example for explaining the driving apparatus of the field emission type light emitting device of the present invention.

In the figure, 1 and 2 are anode voltages applied to the anode terminals A1 and A2. After the end of one frame period of the display image, a non-displaying (blanking = blanking) period in which no image is displayed is provided until the next display image is displayed. In this non-display period, the anode voltages 1 and 2 together, the voltage at which secondary electrons are not emitted from the protective film 81 (Fig. 8), that is, the voltage below the secondary electron emission voltage, for example , The periods 1a and 2a at the GND level (0 volts) are inserted. As a result, the charge of the protective film 81 can be removed every frame to prevent the progress of charging.

However, depending on the material of the protective film 81, the phosphor material of the fluorescent dot 37 (FIGS. 4 and 8), and the like, even if the anode voltage is not emitted from the secondary film from the protective film 81 (FIG. 8), the phosphor dots There may be a case where the 37 (FIGS. 4 and 8) emits light. Since the time is extremely short in the above-described periods 1a and 2a, it is preferable not to emit light even if the phosphor dot 37 emits light even if it is not a big problem. Therefore, in the above-described periods 1a and 2a, the anode voltage is not only a voltage at which secondary electrons are not emitted, but also a voltage at which the phosphor dot 37 does not emit light (phosphor non-emitting voltage), that is, a light emission start voltage. It is more preferable if it is the following voltages. The GND level (0 volt) is a voltage at which secondary electrons are not emitted from the protective film 81, and is also a phosphor non-emitting voltage.

Moreover, the scan pulses applied to the gate terminals and the data pulses applied to the cathode terminals C _{1 to} C _K are the same as in FIG. 6. Scan pulses are not generated in the non-display period.

The periods 1a and 2a in which the anode voltages 1 and 2 are voltages at which secondary electrons are not emitted from the protective film 81 or voltages at which secondary electrons are not emitted from the protective film 81 and at the same time phosphor non-emitting voltages ) Is preferably inserted into the non-display period for each frame described above. However, when the degree of charging is small due to the material of the protective film 81 or the like, it may be inserted about once in a plurality of frames. In this case, with respect to the anode voltages 1 and 2 applied to each of the anode terminals A1 and A2, at the same time, the secondary electrons from the protective film 81 or the voltage at which secondary electrons are not emitted from the protective film 81. The above-described periods 1a and 2a may be inserted alternately without inserting the periods 1a and 2a which are phosphor non-emitting voltages at the same voltage as which is not emitted.

Fig. 2 is a waveform diagram of a second example for explaining the driving apparatus of the field emission type light emitting device of the present invention.

In the figure, 3 and 4 are anode voltages applied to each of the anode terminals A1 and A2. In this example, not only the non-display periods 3a and 4a at the end of one frame period, but also the non-display period is provided at the end of the subframe, and in this non-display period, the anode voltages 3 and 4 are provided with the protective film 81 Is the voltage at which secondary electrons are not emitted from or the secondary electrons are not emitted from the protective film 81 at the same time (3b, 4b) at the phosphor non-emitting voltage, for example, at the GND level (0 volts). ) Is being inserted. Therefore, the antistatic ability is improved compared with the embodiment of FIG.

Also in this example, the scan pulses applied to the gate terminals and the data pulses applied to the cathode terminals C _{1 to} C _K are the same as in FIG. 6. In the non-display period, no scan pulse is generated on the gate electrode.

Next, in addition to the prevention of the drop in the breakdown voltage between the anode electrodes described above, a driving apparatus capable of preventing the deterioration of electron emission by the cleaning effect of the emitter surface will be described. In this case, the waveforms of the anode voltages 1 and 2 (3 and 4 in Fig. 2) are the same as those in Figs. 1 and 2, but are in the non-display period of the image, and the anode voltages 1 and 2 are the protective films. The voltage at which secondary electrons are not emitted from the 81 or the secondary electrons are not emitted from the protective film 81 and at the same time the periods 1a and 2a of the phosphor non-emitting voltage (3a, 3b, in FIG. 2). In 4a and 4b), a refresh pulse is applied to the gate electrode, and the field emission portion is placed in the field emission state.

Specifically, each anode voltage (1, 2 (3, 4)) has a protective film 81 for the refresh pulses that are sequentially turned on, which is the same as the scan pulses 53 to 60 shown in FIG. 6 occurring in the image display period. In the period (1a, 2a (3a, 3b, 4a, 4b)), which is the voltage at which the secondary electrons are not emitted from the second electrode or the secondary electrons are not emitted from the protective film 81, and at the same time, the phosphor non-emitting voltage. Generate. In the field emission section where this refresh pulse is applied to the gate electrode, electrons are emitted from the emitter, flow into the gate electrode, and the surface of the emitter is cleaned by this current, resulting in deterioration of electron emission characteristics. Can be prevented. In addition, while suppressing the progress of the accumulation of charges charged to the insulator layer near the gate electrode, the ability to suppress the progress of the charge of the protective film 81 on the anode substrate 32 side is also improved.

However, it was found that when the refreshing action is too strong, the electron emission characteristics deteriorate. The refreshing action may be effective at the peak value of the gate current, but at present it is estimated that the refresh action is effective at the product of the magnitude of the gate current and the energization time, that is, the effective value of the electron emission amount. Therefore, it is necessary to set the product of the magnitude of the refresh pulse voltage applied to each gate electrode and the application time to an appropriate value.

In order to prevent the charge between the anode electrodes described above, the anode voltages 1 and 2 are simultaneously phosphors at a voltage at which secondary electrons are not emitted from the protective film 81 or at a voltage at which secondary electrons are not emitted from the protective film 81. It is preferable that the period of the non-emitting voltage is longer. Accordingly, the periods 1a and 2a at which the anode voltages 1 and 2 are phosphor non-emitting voltages at the same time as the voltage at which the secondary electrons are not emitted from the protective film 81 or at the voltage at which the secondary electrons are not emitted from the protective film 81. Compared with the length of), the appropriate on-period of the refresh pulse applied to each gate electrode is short.

Therefore, in the above-described periods 1a and 2a, it is not necessary to apply the refresh pulse to each gate electrode every frame. Refresh pulses may be applied to all gate electrodes once every several to several tens of frames. For example, the all-gate electrode is scanned once during the above-described periods 1a and 2a of the plurality of frames, for example, all of the electric currents at the GND level. Alternatively, the all-gate electrode is scanned once in one of the above-described periods 1a and 2a of a plurality of frames, for example, at a GND level.

Further, the scan pulses 53 to 60 shown in Fig. 6 scan at a point in time that no voltage is applied to one gate terminal. However, with respect to the refresh pulse, even if a plurality of gate terminals are turned on at the same time, there is no problem, and the formation of the gate terminals to be turned on at the same time is not a problem. Therefore, for example, when the refresh pulses are simultaneously applied to the plurality of gate terminals, for example, the same refresh pulse is applied to the odd and even gate electrodes or the plurality of gate terminals are simultaneously turned on and the gate terminals to be turned on one by one are scanned. For example, the refresh pulses may be sequentially applied as if G ₁ and G ₂ are turned on at some timing and G ₂ and G ₃ are turned on at the next timing.

In the above-described refreshing action, the degree of deterioration of the field emission unit is greatly changed even with a slight change in conditions. In the image display, most of the emitted electrons are distributed to the anode electrode, and the gate current hardly flows. Therefore, the design conditions of the gate drive circuit for refreshing differ greatly from the design conditions at the time of image display operation. The refresh pulse voltage, the application time and the like are made uniform for each gate electrode. In addition, since the amount of gate current is greatly increased compared with the image display operation, the number of gates for simultaneously turning on the refresh pulse is preferable in consideration of the limitation of the current capacity of the gate power supply.

Although the value varies depending on the design of the FED panel, an example shows that the electron emission amount is excessive at 20 mArms (root mean square) during the period (1a, 2a) where the anode voltage is at the GND level, and the electron emission for refreshing is an example. For example, it is preferable to carry out about once in four frames and to set it to about 400 µArms or less.

Since the electron emission amount is controlled by the gate voltage, the gate voltage is controlled so that the gate voltage for the scan pulse and the refresh pulse for the image display period and the gate voltage for the refresh pulse can be set to different voltages to drive the image. The amount of emission current during refresh can be controlled independently of the amount of electron emission during the period.

3 is a block diagram of a driving device of the field emission type light emitting device according to the present invention. In the figure, 11 is a signal input buffer, 12 is a controller, 13 is a display RAM (random access memory), 14 is a data driver, 15 is an anode power supply / anode switch circuit, 16 is a gate voltage control circuit, 17 is a gate power supply, 18 is a scan driver, 19 is a cathode power supply, and 20 is an FED panel. The overall configuration is the same as that of the drive device for the conventional two-electrode full color FED.

The image signal is input to the controller 12 together with the synchronization signal through the signal input buffer 11, and one frame of image data is stored in the display RAM 13 for each RGB. The controller 12 reads the RGB data stored in the display RAM 13 in a predetermined order according to the selection order of the phosphor dots 37 and transfers the data to the data driver 14. The cathode terminal of the data driver 14. The cathode power source 19 as from a voltage (Vcc), FED panel 20, a data pulse having a pulse width that depends on the gray level of the received supply, RGB data of the in the (cathode electrode (C ₁ ~ C _m )).

The anode power supply / anode switch circuit 15 synchronizes three different voltages (anode selection voltage V _a1 , anode non-selection voltage V _a2 , and phosphor non-emitting voltage GND in FIG. 1) with a synchronous signal. A circuit for switching output at a predetermined timing. The controller 12 controls the anode power supply / anode switch circuit 15 in synchronization with the input synchronization signal, and displays the anode voltage (shown in FIG. 1) at each of the anode terminals A1 and A2 of the FED panel 20. 1, 2) or the anode voltages 3, 4 shown in FIG. The controller 12 also controls the gate voltage control circuit 16 which is supplied with the voltage Vcc from the gate power supply 17, generates a scan pulse, and supplies it to the scan driver 18. The controller 12 controls the scan driver 18 to supply scan pulses to one of the gate terminals G _{1 to} G _2n . In the case of a resolution of 1/4 VGA (320 x 240), n = 240 and m = 960 (the number of cathode terminals 480).

Furthermore, in the case of generating a refresh pulse, the controller 12 determines that the anode voltage is a voltage at which secondary electrons are not emitted from the protective film 81 or a voltage at which secondary electrons are not emitted from the protective film 81 and at the same time a phosphor ratio. In the period of the light emission voltage, the gate voltage control circuit 16 is controlled to generate a refresh pulse having a narrow pulse width. At the same time, the scan driver 18 is controlled, the gate terminals G _{1 to} G _2n are selected and switched at high speed, and all the gate terminals (gates are configured with one period or one frame of the image non-output period as one cycle. A refresh pulse to the electrode).

In the above description, as described with reference to FIG. 8, the effect of the charging of the protective film 81 which is the exposed insulating portion has been described. However, the anode electrode 32 is formed on the surface of the anode substrate 32 of glass without applying the protective film 81. It may be exposed between (36). In this case, the anode substrate 32 becomes an exposed insulator, and part of the electrons emitted from the field emission unit steps around to emit secondary electrons, so that charging progresses, and thus the withstand voltage decreases.

In the above description, a two-electrode full-color FED panel using a straight stripe-shaped anode has been described as a specific example, and a problem and a driving device for solving the problem have been described.

However, an anode selection voltage is applied to one anode electrode, such as a full-duty system using a zig-zag on the zigzag anode known from Fig. 3, etc. of a paper referred to in the prior art, and the phosphor dot 37 is made to emit light. The anode voltage can be made high in the same manner as long as the anode electrode has an adjacent anode electrode at a low voltage and focuses the emission electrons on the phosphor dots 37 which are capable of emitting light.

Not only the two-electrode type but also the three or more anode electrodes, if the same focusing action is used, the anode voltage can be increased. Not only a color FED, but a monochromatic FED is also good. The present invention can also be applied not only to an image display device but also to a case where light is emitted in accordance with image data using a field emission unit in a one-dimensional or two-dimensional array like an optical print head.

As is apparent from the above description, the present invention ends without raising the switching voltage between the anode electrodes even when the anode voltage for selecting and emitting the phosphor dots is high, so that the dielectric breakdown due to the increase in the electric field strength between the electrodes does not occur, and the anode There is an effect that the voltage can be easily increased. Furthermore, the phosphor at which secondary electrons are not emitted from the insulation exposed to the anode voltage, or the voltage at which secondary electrons are not emitted from the exposed insulation, or the voltage at which secondary electrons are not emitted from the exposed insulation By inserting the level of the non-luminous voltage, it is possible to suppress the progress of charging on the surface of the anode substrate and to prevent the fall of the withstand voltage. As a result, stable high brightness can be achieved.

A refresh pulse is applied to the gate electrode in a period in which each anode voltage is a voltage at which secondary electrons are not emitted from the exposed insulation or a voltage at which secondary electrons are not emitted from the exposed insulation and at the same time a phosphor non-emitting voltage. The effect is that the emitter electrons can clean the emitter surface and prevent deterioration of the electron-emitting characteristics. Since the electron emission amount is controlled by the gate voltage, the voltage at which the secondary electrons are not emitted from the insulator exposed by the gate voltage and the anode voltage of the image display period, or the voltage at which the secondary electrons are not emitted from the exposed insulator and at the same time the phosphor ratio When the gate voltage at the light emission voltage is set at different potentials and driven, it is possible to control the amount of emission current in the refresh period regardless of the brightness of the display image.

Claims (4)

A plurality of anode electrodes are alternately connected in common, and a plurality of anode terminals are drawn out, an insulating portion is exposed on the anode substrate, and a plurality of field emission means are arranged to face the plurality of anode electrodes, and to each of the anode terminals. And the anode selection voltage and the anode non-selection voltage, which is a positive voltage lower than the anode selection voltage, are alternately supplied, so that electrons from the previously selected field emission means are focused to emit the phosphor dots on the anode electrode. And a switching driving means, wherein the switching driving means alternately supplies the anode selection voltage and the anode non-selection voltage to each of the anode terminals in the image output period, and during the image output period. In at least some of the image non-output periods in Drive device of the field emission type light-emitting device characterized in that the voltage that the secondary electrons are not emitted from the insulating portion is applied. A plurality of anode electrodes are alternately connected in common, a plurality of anode terminals are drawn out, an insulating portion is exposed on the anode substrate, and a plurality of field emission means are arranged opposite to the plurality of anode electrodes, and each of the anode terminals And the anode selection voltage, and the anode non-selection voltage, which is a positive voltage lower than the anode selection voltage, are alternately supplied, so that electrons from the previously selected field emission means are focused to emit the phosphor dots on the anode electrode. And a switching driving means, wherein the switching driving means alternately supplies the anode selection voltage and the anode non-selection voltage to each of the anode terminals in the image output period, and at the same time during the image output period. In at least a portion of the image non-output period in Drive device of the field emission type light-emitting device which comprises applying a voltage that is isolated from the parts of the secondary electrons are not emitted, and also the non-light emitting phosphor voltage of voltage. A gate voltage output means as set forth in claim 1 or 2, wherein said gate voltage output means has said gate voltage output means within said period in which a voltage at which secondary electrons are not emitted from said insulation portion is applied. A device for driving a field emission type light emitting device, characterized in that a gate pulse is applied to a gate electrode of each field emission means. 4. The electric field according to claim 3, further comprising a gate voltage control means, the gate voltage control means controlling the voltage value of the gate pulse to a value different from the voltage value of the scanning pulse output in the image output period. An apparatus for driving a light emitting device.