JP5126276B2 - Image display device - Google Patents

Description

  The present invention relates to an image display device and a driving method of the image display device, and more particularly to a technique effective when applied to an image display device in which a plurality of luminance modulation elements are arranged in a matrix.

  Examples of image display devices in which a plurality of luminance modulation elements are arranged in a matrix include a liquid crystal display, a field emission display (FED), and an organic electroluminescence display. The luminance modulation element is a device that changes luminance by an applied voltage. Here, the luminance corresponds to transmittance or reflectance in the case of a liquid crystal display, and brightness of light emission in the case of a display using a light emitting element such as a field emission display or an organic electroluminescence display.

  Such a display has an advantage that the thickness of the image display device can be reduced.

  Therefore, it is particularly effective as a portable image display device.

  Examples of the background art include Patent Document 1, Non-Patent Document 1, Non-Patent Document 2, Non-Patent Document 3, Non-Patent Document 4, Non-Patent Document 5, and the like. These documents will be described in detail later.

JP-A-2002-162927

1997 SID International Symposium Digest of Technical Papers, pages 1073-1076 (issued in May 1997) 1999 SID International Symposium Digest of Technical Papers, pp. 372-375 (May 1999) EURODISPLAY '90, 10 th International Display Research Conference Proceedings (vde-verlag, Berlin, 1990), pp. 374-377 Japanese Journal of Applied Physics, Vol.34, Part 2, No.6A, pp. L705 ~ L707 (1995) Japanese Journal of Applied Physics, Vol.36, Part 2, No.7B, pp. L939 to L941 (1997)

In a portable image display device, low power consumption is an important characteristic. In a stationary or desktop display device, it is desirable that the power consumption is small from the viewpoint of effective use of energy or from the viewpoint of reducing heat generation of the display device.
However, conventionally, a large amount of electric power for charging and discharging the electric capacity of the luminance modulation element has been a factor for increasing the power consumption.

  In order to solve this problem, in an image display device in which unipolar luminance modulation elements are arranged in a matrix, a method for reducing charge / discharge power by setting non-selected electrodes to high impedance is, for example, the applicant's method. It is disclosed in Japanese Patent Application Laid-Open No. 2002-162927. In this method, the load capacitance of the data line circuit is substantially reduced by setting the non-selected scanning line in a higher impedance state than the selected scanning line, thereby reducing the charge / discharge power. On the other hand, in this method, since the potential of the electrode in the high impedance state is in a floating state, the potential is not constant. That is, an unintended voltage (induced voltage) is induced in the high impedance state electrode.

In the above disclosed example, based on the fact that this induced voltage tends to have a specific polarity, an image display method in which this induced voltage hardly affects the display image by combining the luminance modulation characteristics of the unipolar luminance modulation element is disclosed. doing.
However, since the electrode in a high impedance state is indefinite in principle, an unintended voltage is sometimes induced, which may affect the display state.
To solve this problem, a method for controlling the polarity of the induced voltage by setting only the scanning line adjacent to the selected scanning line to a low impedance state is disclosed in Japanese Patent Application Laid-Open No. 2002-162927. However, since it is indefinite in principle for electrodes in a high impedance state, even when the method disclosed in the above-mentioned known example is used, an unintended voltage is sometimes induced and affects the display state. There can be.

In order to describe the features of the present invention, the problems of the conventionally disclosed driving method will be described in detail. Here, an example in which a combination of a thin film electron source and a phosphor is used as the luminance modulation element will be described.
FIG. 2 is a diagram showing a schematic configuration of the luminance modulation element matrix. A luminance modulation element 301 is formed at each intersection of the row electrode 310 and the column electrode 311. Note that FIG. 2 shows a case of 3 rows × 3 columns. However, in the case of a color display device, the luminance modulation element 301 is actually the same as the number of sub-pixels in the case of a color display device. Is arranged. That is, the number N of rows and the number M of columns are typically N = several hundreds to thousands of rows and M = several hundreds to thousands of columns, respectively.

  In the case of color image display, one pixel is formed by a combination of red, blue, and green sub-pixels. In this specification, sub-pixels ( Sub-pixels) are also called “pixels”. Alternatively, a pixel for monochrome display and a sub-pixel for color display may be collectively referred to as “dot”.

  FIG. 3 is a timing chart for explaining a driving method of a conventional image display apparatus. A negative pulse (scanning pulse 750) having an amplitude (VK) is applied from one of the row electrodes 310 (selected row electrode) from the row electrode drive circuit 41, and at the same time from the column electrode drive circuit 42 to the column. A positive pulse (data pulse 760) having an amplitude (Vdata) is applied to how many electrodes 311 (selected column electrodes). The luminance modulation element 301 in which the two pulses are overlapped emits light because a voltage sufficient to emit light is applied. In the luminance modulation element 301 to which no positive pulse having an amplitude (Vdata) is applied, a sufficient voltage is not applied and light is not emitted. The row electrode 310 to be selected, that is, the row electrode 310 to which the scan pulse is applied is sequentially selected, and the data pulse to be applied to the column electrode 311 is also changed corresponding to the row. When all rows are scanned in this way during one field period, an image corresponding to an arbitrary image can be displayed. In the matrix display device, the invalid power consumption of the drive circuit becomes a problem. The reactive power consumption is power consumed to charge / discharge electric charges in the capacitance of the element to be driven, and does not contribute to light emission.

  Now, let the capacitance per one of each luminance modulation element 301 be Ce. As can be seen from FIG. 2, each column electrode drive circuit 42 is connected to a load capacitance of NCe. Therefore, when a data pulse is applied to m luminance modulation elements per row, a load capacity of mNCe is connected in the entire column electrode drive circuit 42. The power for charging / discharging the load capacity is the above-described reactive power consumption. When the number of times the screen is rewritten per second (field frequency) is f, the reactive power (Pdata) in the column electrode drive circuit 42 is expressed by the following equation (1).

Pdata = f, N2, M, Ce, (Vdata) 2 (1)
Next, consider a case where the scanning lines other than the scanning line to which the scanning pulse is applied (referred to as the scanning line in the selected state) are in a floating state (FIG. 4). In this way, the load capacity of the data line circuit is substantially reduced, so that the reactive power in the column electrode drive circuit 42 is reduced. In order to place a non-selected scanning line in a floating state, the non-selected scanning line may be set to a high impedance state. A reactive power reduction method using this method is disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-162927 by the present applicant. In this case, the load capacity of the entire data line circuit is expressed by the following equation (2).
(2) Formula

This takes a maximum value at m = M / 2. In the driving method in which the scanning line in the non-selected state is connected to low impedance, the load capacity of the data line takes the maximum value at m = M, but the scanning line in the non-selected state is set to the high impedance state compared to this maximum value. The maximum value in the driving method is reduced to 1/4. On the other hand, if the non-selected scanning lines are set in a floating state, the potentials of these scanning lines become indefinite, which may affect the display image. However, as disclosed in Japanese Patent Application Laid-Open No. 2002-162927 of the present applicant, the polarity of the voltage induced in the non-selected scanning line is induced in a specific direction. That is, the voltage VF, scan induced in the non-selected scanning line is expressed by the following equation (3).
(3) Formula VF, scan = (m / M) Vdata = x Vdata
Here, x = m / M is a ratio of the number of luminance modulation elements in an ON state in one row and is called a lighting rate. Vdata is the amplitude voltage of the data pulse.
The lighting rate x is positive or zero. Therefore, when Vdata is set to a positive voltage as in the drive waveform of FIG. 4, the induced voltage VF, scan is positive or zero. In the case of FIG. 4, since luminance is modulated when a negative voltage is applied to the scanning line, this induced voltage has a polarity that does not cause luminance modulation. Therefore, the influence of the induced voltage on the display image can be made sufficiently small by using a unipolar luminance modulation element and connecting in a direction in which the luminance is not modulated with the polarity of the induced voltage.

Here, a “unipolar” luminance modulation element will be described.
An element that does not emit light even when a reverse polarity voltage is applied, and more generally, an element whose luminance modulation state is not selected is called a “unipolar luminance modulation element” in the sense of luminance modulation only with positive polarity. I will decide. On the other hand, an element that emits light even when a voltage of opposite polarity is applied, or an element whose luminance modulation state is selected, is referred to as a “bipolar luminance modulation element” in the sense that luminance modulation is performed with two positive and reverse polarities. I will call it.

  As is apparent from the above description, “does not modulate the luminance with the reverse polarity” is sufficient if the crosstalk of the display does not occur even when the reverse polarity voltage is applied. Even if an element that modulates brightness only slightly by applying a reverse polarity voltage is virtually invisible to the human eye, or is in a range that does not cause a problem as a display device, it is substantially “no brightness modulation”. Therefore, it can be regarded as a “unipolar” luminance modulation element.

  The unipolar luminance modulation element will be further described in detail. Consider a luminance modulation element having the luminance-voltage characteristics shown in FIGS. 5 (a) and 5 (b). Here, a light emitting element will be described as an example of the luminance modulation element. In FIG. 5, the vertical axis represents the luminance, that is, the brightness in the case of the light emitting element, and the horizontal axis represents the voltage applied to the luminance modulation element. In the characteristics shown in FIG. 5A, the luminance increases when a positive voltage is applied, but the luminance is substantially zero when a negative voltage is applied. That is, the luminance modulation element having the characteristic (a) is unipolar. On the other hand, in FIG. 5B, the luminance also changes when a negative voltage is applied. That is, the luminance modulation element having the characteristic (b) is bipolar.

  Consider a case where a matrix of N rows × M columns is constituted by these luminance modulation elements and the drive voltage shown in FIG. 4 is applied. A scanning pulse having a negative voltage VK is applied to the selected row, and a half-selected state ("half-selected") is set. A data pulse of a positive voltage Vdata is applied to the data line of the luminance modulation element to be lit in the selected row. Therefore, a voltage Vdata−VK = | Vdata | + | VK | is applied to the luminance modulation element at the intersection of the selected scanning line and the selected data line, whereby the luminance modulation element emits light (point C in the figure).

  At this time, the voltage VF, scan expressed by the equation (3) is induced in the scanning line in the non-selected state. Therefore, a voltage of −VF, scan is applied to the luminance modulation element at the intersection of the non-selected scanning line and the non-selected data line (point D in the figure). In the case of the bipolar luminance modulation element shown in FIG. 5B, the induced voltage −VF, scan emits light slightly (point D in the figure). That is, an unintended luminance modulation element emits light. For this reason, the display image is disturbed. This is a problem when the non-selected scanning line is set to high impedance.

  This problem can be solved by using a unipolar luminance modulation element. In the case of the unipolar luminance modulation element shown in FIG. 5A, no light is emitted even when −VF, scan is applied (point D in the figure). Therefore, even if the non-selected scanning line has a high impedance, the display is not disturbed.

  In the above description, the scanning pulse is a negative voltage and the data pulse is a positive voltage. Conversely, it goes without saying that the same applies when the scanning pulse is a positive voltage and the data pulse is a negative voltage. In this case as well, equation (6) holds, and the voltage VFG, scan induced on the scan electrode becomes a negative voltage. Since this has a reverse polarity for the luminance modulation element, if a unipolar luminance modulation element is used, no erroneous display occurs as described above.

Examples of the bipolar luminance modulation element include a liquid crystal element and a thin film type inorganic electroluminescence element. Examples of the unipolar luminance modulation element include an organic electroluminescence element and an electron emission element combined with a phosphor.
The organic electroluminescence element is also called an organic light emitting diode, and has a diode characteristic that it emits light when a forward voltage is applied, but does not emit light with a reverse polarity voltage. The organic electroluminescent element is described in Non-Patent Document 1, for example. Alternatively, a polymer-type organic electroluminescent element is described in Non-Patent Document 2.

  An example of a luminance modulation element in which a phosphor and an electron-emitting element are combined is described in Non-Patent Document 3, for example. In this example, the electron-emitting device includes an electron-emitting emitter tip and a gate electrode that applies an electric field to the emitter tip. When a positive voltage is applied to the gate electrode with respect to the emitter tip, electrons are emitted from the emitter tip to cause the phosphor to emit light, but when a negative voltage is applied, no electrons are emitted. That is, it is a unipolar luminance modulation element.

As described above, Patent Document 1 of the present applicant discloses that the influence of an induced voltage on a display image can be reduced by using a unipolar luminance modulation element. However, the forward polarity voltage of the luminance modulation element is sometimes induced in the scanning electrode in the floating state.
For example, due to capacitive coupling between adjacent scan electrodes, a forward polarity voltage may be induced in the adjacent scan line when a scan pulse is applied. In order to prevent this, Patent Document 1 of the present applicant discloses a method of setting only the scanning line adjacent to the scanning line to which the scanning pulse is applied to a low impedance state.

  However, the method disclosed in Patent Document 1 may not prevent the generation of forward polarity induced voltage. Even in such a case, the present invention provides a method for minimizing the influence on a display image in a display device including a unipolar luminance modulation element while minimizing the generation of a forward polarity induced voltage. It is to provide.

The present invention has been made in order to solve the above-described problems of the prior art, and an object of the present invention is to provide a technique capable of reducing reactive power in a luminance modulation element matrix in an image display device. It is to provide.
Still another object of the present invention is to provide a technique for further stabilizing the induced voltage of an electrode in a high impedance state, thereby stably displaying an image.
In addition, in a display device using a luminance modulation element in which an electron-emitting element and a phosphor are combined, if there is a floating electrode, abnormal discharge is likely to occur due to a high voltage applied to the phosphor. It was.

Of the inventions disclosed in this application, the outline of typical ones will be briefly described as follows.
It has a plurality of luminance modulation elements that modulate the luminance by applying a positive voltage and do not modulate the luminance by applying a reverse polarity voltage, and have a plurality of parallel scan electrodes and a plurality of parallel data electrodes. The luminance modulation element is disposed at the intersection of the scan electrode and the data electrode, and is connected to the plurality of scan electrodes and connected to the plurality of data electrodes. In the image display device having the second driving means, at a certain point in the scanning period, the scanning electrode is in a selected state to which a scanning pulse is applied and in a non-selected state other than that. Divided,
The number of scanning lines in the selected state is n1,
The scanning line in the non-selected state is divided into a non-selected scanning line in a high impedance state and a non-selected scanning line in a low impedance state, and the non-selected scanning line in the high impedance state is in the selected state. A non-selected scanning line in a low impedance state that is in a higher impedance state than a certain scanning line is in a lower impedance state than a non-selected scanning line in the high impedance state;
The number of the non-selected scanning lines in the low impedance state is n1 × 2 or more.

  In other words, using mathematical formulas, it is as follows. The impedance of the scanning line in the selected state is Z (SEL), the impedance in the unselected state in the high impedance state is Z (NS, HZ), and the impedance in the unselected state in the low impedance state is Z (NS, LZ). The number of scanning lines in the selected state is N (SEL), the number of scanning lines in the non-selected state in the high impedance state N (NS, HZ), and the number of scanning lines in the non-selected state in the low impedance state is N If (NS, LZ), Z (SEL) <Z (NS, HZ), Z (NS, LZ) <Z (NS, HZ), and N (NS, LZ) ≧ 2 × N (SEL) It is characterized by being satisfied.

  It has a plurality of luminance modulation elements that modulate the luminance by applying a positive voltage and do not modulate the luminance by applying a reverse polarity voltage, and have a plurality of parallel scan electrodes and a plurality of parallel data electrodes. , An image display device having a first driving means connected to the plurality of scanning electrodes and outputting a scanning pulse, and a second driving means connected to the plurality of data electrodes, wherein the scanning electrode comprises a scanning pulse. Is set to at least three states: a high impedance state non-selected state and a low impedance non-selected state, and the low impedance state non-selected state scanning line is in the high impedance state. The non-selected state is a lower impedance state than the scanning line, and the low-impedance state non-selected state and the high-impedance state non-selected state alternate Characterized in that it is repeated.

  It has a plurality of luminance modulation elements that modulate the luminance by applying a positive voltage and do not modulate the luminance by applying a reverse polarity voltage, and have a plurality of parallel scan electrodes and a plurality of parallel data electrodes. , An image display device having a first driving means connected to the plurality of scanning electrodes and outputting a scanning pulse, and a second driving means connected to the plurality of data electrodes, wherein the first driving means is , Having at least three states, a selected state in which a scan pulse is applied, a non-selected state in a high impedance state, and a non-selected state in a low impedance state, and an output impedance when outputting the unselected state in the low impedance state is , The impedance is lower than the output impedance when outputting the non-selected state of the high impedance state, and the non-selected state of the low impedance state and And repeating the non-selected state of the serial high-impedance state alternately.

  It has a plurality of luminance modulation elements composed of a combination of an electron-emitting device and a phosphor, and has a plurality of scan electrodes parallel to each other and a plurality of data electrodes parallel to each other, and is connected to the plurality of scan electrodes. In an image display device having a first driving means for outputting a scanning pulse and a second driving means connected to the plurality of data electrodes, the scanning electrode has a selected state to which a scanning pulse is applied, and a high state. The low-impedance state non-selected scanning line has at least three states, ie, an impedance state non-selected state and a low-impedance non-selected state. The non-selected state of the low impedance state and the non-selected state of the high impedance state are alternately repeated.

  FIG. 6 shows a voltage waveform that appears in a certain row electrode 310 during operation. FIG. 6 shows an observation waveform in a thin film electron source matrix composed of 60 row electrodes 310 and 60 column electrodes 311. In this figure, the horizontal scale is 2 ms and the vertical scale is 2V. A negative pulse (a in the figure) is a scanning pulse, and a positive pulse (b in the figure) on the right side of the figure is an inversion pulse. Only when these two pulses are applied is the low impedance state, and the other periods are the high impedance state. The positive pulse (c in the figure) appearing other than that is an induced potential induced in a high impedance period. As described above, since this is a reverse polarity for the thin film electron source, no electron emission occurs. On the other hand, a negative voltage is induced during a period (d in the figure) immediately after applying the scanning pulse until applying the inversion pulse. This is an induced potential due to the influence of applying a negative scan pulse and the application of a negative scan pulse to the adjacent row electrode 310.

As can be seen from this figure, the induced voltage of forward polarity tends to persist once induced.
Therefore, in the present invention, an induced voltage having a forward polarity is applied continuously or continuously to a non-selected scanning line by appropriately setting the scanning line in the non-selected state to a low-impedance non-selected voltage. prevent. This stabilizes the image display.

  Thus, in the present invention, the number of non-selected scanning lines in a low impedance state increases. Therefore, there is a concern that reactive power will increase. Therefore, the reactive power in the image display device according to the present invention is calculated.

  Consider a matrix display with N effective scan lines and M data lines. At a certain moment, one scanning line is applied with a scanning pulse, and the number of non-selected scanning lines in a low impedance state is n0-1. Here, the number of effective scanning lines is the number of scanning electrodes N0 divided by the number of scanning lines that are scanned simultaneously. For example, if only one scanning line is scanned at a certain time (“one-row simultaneous driving method”), N = N0. In the case of a driving method in which the upper and lower portions of the screen are divided into two, and one scanning line in each of the upper half area and the lower half area is simultaneously scanned (“two rows simultaneous driving method”), N = N0 / 2.

FIG. 7 is an equivalent circuit diagram in this case. It is a figure which shows the equivalent circuit at the time of selecting m column electrodes 311 and fixing (Mm) non-selected column electrodes 311 to the ground potential. As shown in FIG. 7, a total of n0 scanning lines including one selected scanning line and (n0-1) non-selected scanning lines are in a low impedance state, and the remaining (N-n0) scanning lines. Are in a floating state. The load capacity of the entire m selected column electrodes 311 at this time is expressed by the following equation (4).
(4) Formula

Here, b = n0 / N is obtained by dividing the number of scanning lines in a low impedance state by the number of effective scanning lines (hereinafter referred to as a low impedance ratio in this specification), and x = m / M is lit in one row. It is the ratio (lighting rate) of the dots.
As described above, the reactive power of the data line is proportional to the load capacity of the data line expressed by equation (4). Therefore, knowing the value of the load capacity of the data line can determine the magnitude of reactive power.
FIG. 8 is a plot of data line load capacity as a function of lighting rate. This figure is calculated with N = 500. The number of low impedance scanning lines n0 = 1, 10, 50, 100 is obtained.
As described above, the load capacity of the data line varies depending on the lighting rate x. The maximum value regarding the lighting rate of the load capacity is expressed by the following equation (5).
(5) Formula Ccol (max) = NMCe / {4 (1-b)}
Since n0 = 1 corresponds to the case where only the selected scanning line has a low impedance, it corresponds to the conventional driving method. Looking at the increase in load capacity relative to the conventional driving method (n0 = 1), the increase is only 2% at n0 = 10 (low impedance ratio b = 10/500).
Even when n0 = 50 (b = 10%), the increase in load capacity is only 10%.

  Compared to the drive method in which all non-selected scan lines are set to low impedance non-select potential (referred to as “fixed potential drive”), the drive method in which all non-selected scan lines are set to high impedance is the reactive power of the data line circuit. Is reduced to ¼ (= 25%) as described above. Therefore, if the low impedance ratio b is limited to about 10%, the reactive power of the data line circuit in the image display device of the present invention is only 28% in the case of the fixed potential driving, and the display is performed without impairing the low power effect. An image stabilization effect can be obtained.

Here, “fixed potential” means “fixed potential” with respect to the floating potential. That is, it indicates a state in which the set value and the potential on the actual wiring match, and is essentially in a low impedance state. In other words, it does not necessarily mean that it is fixed at a constant potential in time.
The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.
According to the image display device of the present invention, it is possible to reduce reactive power accompanying charging / discharging of the capacitive component of the luminance modulation element, and to reduce power consumption.

It is a figure for demonstrating the drive method of the image display apparatus of this invention. It is a figure which shows schematic structure of a brightness | luminance modulation element matrix. It is a figure for demonstrating the drive method of the conventional image display apparatus using a luminance modulation element matrix. It is a figure for demonstrating the drive method of the conventional image display apparatus using a luminance modulation element matrix. It is the figure which showed typically the voltage dependence of the luminance modulation characteristic of the unipolar and bipolar luminance modulation element. It is the figure which observed the voltage on the scanning electrode of a high impedance state in the conventional image display apparatus. It is a figure showing the equivalent circuit of the image display apparatus of this invention. It is a figure which shows the relationship between a lighting rate and load capacity in the image display apparatus of this invention. It is a top view which shows the structure of a part of thin film electron source matrix of the electron source plate of Embodiment 1 of this invention. It is a top view which shows the positional relationship of the electron source plate of Embodiment 1 of this invention, and a fluorescence display board. It is principal part sectional drawing which shows the structure of the image display apparatus of Embodiment 1 of this invention. It is a connection diagram which shows the state which connected the drive circuit to the display panel of Embodiment 1 of this invention. It is a figure which shows the drive waveform in Embodiment 1 of this invention. It is a top view which shows the structure of a part of thin film electron source matrix of the electron source plate of Example 2 of this invention. It is principal part sectional drawing which shows the structure of the image display apparatus of Example 2 of this invention. It is a connection diagram which shows the state which connected the drive circuit to the display panel of Example 2 of this invention. It is a figure which shows the drive waveform in Example 2 of this invention. It is the schematic which extracted the brightness | luminance modulation element and the electrode in this invention. It is a figure which shows an example of the row electrode drive circuit in Example 2 of this invention. It is a figure which shows another example of the row electrode drive circuit in Example 2 of this invention. It is a top view which shows the structure of a part of thin film electron source matrix of the electron source plate of Example 3 of this invention. It is principal part sectional drawing which shows the structure of the image display apparatus of Example 3 of this invention. It is a connection diagram which shows the state which connected the drive circuit to the display panel of Example 3 of this invention. It is a figure which shows the drive waveform in Example 3 of this invention. It is a voltage waveform diagram which shows the definition of the scanning period and non-scanning period in this specification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

  The image display apparatus according to Embodiment 1 of the present invention uses a display panel in which a luminance modulation element of each dot is formed by a combination of a thin film electron source matrix, which is an electron emission electron source, and a phosphor, and a row of the display panel. A drive circuit is connected to the electrode and the column electrode.

  A thin-film electron source is an electron-emitting device having a structure in which an electron acceleration layer such as an insulating layer is inserted between two electrodes (an upper electrode and a lower electrode). Hot electrons accelerated in the electron acceleration layer are passed through the upper electrode. Then, it is discharged in a vacuum. Examples of thin-film electron sources include MIM electron sources composed of metal-insulator-metal, ballistic electron surface emitting devices using porous silicon or the like for the electron acceleration layer (for example, Non-Patent Document 4), electrons Those using a semiconductor-insulator laminated film as an acceleration layer (for example, Non-Patent Document 5) are known.

Hereinafter, an example using the MIM electron source will be described.
Here, the display panel includes an electron source plate on which a thin film electron source matrix is formed and a fluorescent display plate on which a phosphor pattern is formed.

FIG. 9 is a plan view showing a partial configuration of the thin film electron source matrix of the electron source plate of the present embodiment, and FIG. 10 shows the positional relationship between the electron source plate and the fluorescent display plate of the present embodiment. FIG.
FIG. 11 is a cross-sectional view of the main part showing the configuration of the image display apparatus according to the present embodiment. FIG. 11 (a) is a cross-sectional view taken along the line AB shown in FIGS. FIG. (B) is a cross-sectional view taken along the line C-D shown in FIGS. 9 and 10. However, in FIG. 9 and FIG. 10, the illustration of the substrate 14 is omitted.

Furthermore, in FIG. 11, the scale in the height direction is arbitrary. That is, the lower electrode 13 and the upper electrode bus line 32 have a thickness of several μm or less, but the distance between the substrate 14 and the substrate 110 is about 1 to 3 mm.
Further, in the following description of the structure of the image display device, description will be made with reference to a drawing of an electron source matrix of 3 rows × 3 columns. These drawings are ones of electron source matrices having a large number of rows and columns. It is drawing which showed the part. The number of rows / columns in a typical display panel is several hundreds to thousands of rows and thousands of columns.

9 and 11, a thin film electron source is formed at the intersection of the lower electrode 13 (acting as a scanning line) and the upper electrode bus line 32 (acting as a data line). The thin film electron source has a structure in which an upper electrode 11, a tunnel insulating layer 12, and a lower electrode 13 are stacked. The upper electrode 11 is connected to the upper electrode bus line 32.
When a voltage at which the upper electrode 11 becomes positive is applied between the upper electrode 11 and the lower electrode 13, electrons are accelerated in the tunnel insulating layer 12 to generate hot electrons, and are passed through the upper electrode 11 in vacuum. Electrons are emitted to
In FIG. 9, a region 35 surrounded by a dotted line indicates an electron emission portion (electron source element of the present invention).

The electron emitting portion 35 is a place defined by the tunnel insulating layer 12, and electrons are emitted from this region into a vacuum.
Since the electron emission portion 35 is covered with the upper electrode 11 and does not appear in the plan view, it is shown by a dotted line.

The fluorescent display panel according to the present embodiment includes a black matrix 120 formed on a substrate 110 such as soda glass, red (R), green (G), and blue (B) phosphors (114A to 114C), and And a metal back film 122 (electron acceleration electrode) formed thereon.
The distance between the substrate 110 and the substrate 14 was about 1 to 3 mm.

The spacer 60 is inserted to prevent the display panel from being damaged by a force from outside the atmospheric pressure when the inside of the display panel is evacuated.
Therefore, when manufacturing a display device having a display area of about 4 cm wide × 9 cm long using glass having a thickness of 3 mm for the substrate 14 and the substrate 110, the atmospheric pressure is obtained by the mechanical strength of the substrate 110 and the substrate 14 itself. Therefore, it is not necessary to insert the spacer 60.

The shape of the spacer 60 is, for example, a rectangular parallelepiped shape as shown in FIG.
Here, the support columns of the spacer 60 are provided every three rows, but the number of support columns (arrangement density) may be reduced as long as the mechanical strength can withstand.
The spacer 60 is made of glass or ceramics, and plate-like or columnar columns are arranged side by side.

The sealed display panel is evacuated to a vacuum of about 1 × 10 −7 Torr and sealed.
In order to maintain a high degree of vacuum in the display panel, a getter film is formed or a getter material is activated at a predetermined position (not shown) in the display panel immediately before or after sealing.
The manufacturing method of the display panel having the configuration shown in FIGS. 9, 10, and 11 is disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-162927 of the present applicant.
FIG. 12 is a connection diagram illustrating a state in which a drive circuit is connected to the display panel of the present embodiment.

  The row electrode 310 (matches the lower electrode 13 in the present embodiment) is connected to the row electrode drive circuit 41, and the column electrode 311 (matches the upper electrode bus line 32 in the present embodiment) is connected to the column electrode drive circuit 42. Is done.

Here, the connection between each drive circuit (41, 42) and the electron source plate is, for example, a tape carrier package bonded with an anisotropic conductive film, or a semiconductor constituting each drive circuit (41, 42). The chip is formed by chip-on-glass or the like that is directly mounted on the substrate 14 of the electron source plate.
An acceleration voltage of about 3 to 6 KV is constantly applied to the metal back film 122 from the acceleration voltage source 43.

FIG. 1 is a timing chart showing an overall image of an example of a waveform of a drive voltage output from each drive circuit shown in FIG.
In the figure, the dotted line indicates a high impedance output.
Actually, the output impedance may be about 1 to 10 MΩ, and in this embodiment, it is set to 5 MΩ.

  A scanning pulse 750 is sequentially applied to the row power intensity 310 (scanning electrode). A data pulse 760 is applied to the column electrode 311. In a pixel to which the scan pulse 750 and the data pulse 760 are applied simultaneously, a sufficient voltage is applied between the upper electrode 11 and the lower electrode 13 to emit electrons. The electrons are accelerated by the acceleration voltage applied to the acceleration electrode 122 on the phosphor plate, and then collide with the phosphor 114 to cause the phosphor to excite and emit light.

An image is displayed on the display panel by scanning all the row electrodes 310.
An inversion pulse 755 is applied to the row electrode 310 once within one field period of the video signal. A voltage having a polarity opposite to that at the time of electron emission is applied to the thin film electron source by the inversion pulse 755, thereby improving the life characteristics of the thin film electron source. When the inversion pulse 755 is applied during the blanking period of the video signal, the consistency with the video signal is good.

FIG. 13 is a detailed diagram of the timing chart of FIG.
At time t (1), a scanning pulse 750 is applied to the row electrode 310R1 to make it a selected state.
When the data pulse 760 is simultaneously applied to the column electrodes 311C1 and C2, the phosphors of the pixels (R1, C1) and (R1, C2) emit light.

At time t (2), a scanning pulse 750 is applied to the row electrode 310R2 to select it. At the same time, when the data pulse 760 is applied to the column electrode 311C1, the phosphor of the pixel (R2, C1) emits light.
In this manner, when the voltage waveform is applied to FIG. 13, the hatched pixels in FIG. 12 emit light. By changing the waveform of the data pulse 760, any pixel can be made to emit light.
In FIG. 13, the dotted line portion in the voltage waveform diagram applied to the row electrode 310 is in a high impedance state. At time t (2), a scan pulse 750 is applied to the row electrode 310R2, and during this period, the adjacent row electrode 310R1 is in the low impedance state non-selected state 751. The non-selected state in the low impedance state refers to a state in which the output impedance of the drive circuit is set lower than that in the high impedance state and the non-selected state, that is, the state in which the scan pulse 750 is not applied in this embodiment.

At time t (5) and t (8), the row electrode 310R1 is again set to a low impedance state non-selected state 751.
As can be seen from FIG. 13, the number n1 of row electrodes selected by applying the scan pulse 750 at a certain time, for example, time t (8), is one of the row electrodes R8. On the other hand, the number of non-selected scanning lines in the low impedance state is three of the row electrodes R1, R4 and R7, which is n1 × 2 or more.

  Since the row electrode R8 to which the scan pulse 750 is applied is also in the low impedance state, the number n0 of row electrodes in the low impedance state is four. This corresponds to n0 in the equation (4). Usually, since the number N of row electrodes is about 500 to 1000, b = n0 / N is about 0.6% to 0.3%. Therefore, as calculated from the equation (4), the reactive power due to setting the non-selected state of the low impedance state is sufficiently small.

  A second embodiment of the present invention will be described with reference to FIGS. 14, 15, 16, and 17. FIG. The image display apparatus according to the second embodiment uses a display panel in which a luminance modulation element of each dot is formed by a combination of a thin film electron source matrix, which is an electron emission electron source, and a phosphor. A drive circuit is connected to the column electrode.

  FIG. 14 is a plan view of a cathode plate among the display panels constituting the image display device of the second embodiment. 15 and 16 are cross-sectional views of the display panel constituting the image display apparatus according to the second embodiment. The cross section between A and B shown in FIG. 14 corresponds to FIG. 15A, and the cross section between C and D corresponds to FIG. In this embodiment, a thin film electron source is formed at the intersection of the row electrode 310 (same as the upper electrode bus line 32) and the column electrode 311 (same as the lower electrode 13). In FIG. 14, electrons are emitted from the electron emission portion 35. The emitted electrons are accelerated by the voltage applied to the metal back film 122 and then irradiated to the phosphors 114A, 114B, and 114C, and the phosphors are excited to emit light.

14, 15, and 16 illustrate a matrix of 4 rows × 3 columns, but an actual display device has hundreds to thousands of rows and thousands of columns. These figures show some of them.
As shown in FIGS. 14 and 15A, a spacer electrode 315 is provided between the row electrode 310 of the second row and the row electrode 310 of the third row. The spacer electrode 315 was at ground potential. Then, the spacer 60 is installed on the spacer electrode 315. The spacer 60 provides conductivity with an appropriate resistance value. The upper end of the spacer 60 is connected to the metal back film 122, and the lower end is connected to the spacer electrode 315. Therefore, the electric field distribution near the spacer 60 is uniform between the phosphor screen 110 and the substrate 14. Further, even when electrons are irradiated to the spacer 60 to charge the spacer, the charged charge is removed because the charged charge flows to the metal back film 112 or the spacer electrode 315. In this way, the electric field distribution in the vicinity of the spacer 60 is kept uniform, and adverse effects such as distorting the electron beam trajectory can be prevented.
The number of spacers varies depending on the thickness of the substrate used and the pitch of the electrodes. In this embodiment, the number is about one for every 40 row electrodes.

FIG. 16 shows the connection between the display panel and the drive circuit in this embodiment. Each row electrode 310 is connected to the row electrode drive circuit 41, and each column electrode 311 is connected to the column electrode drive circuit 42. The spacer electrode 315 may be set to substantially the same potential as the row electrode 310 or the column electrode 311. In this embodiment, the ground potential is set. The metal back film 122 is connected to the acceleration voltage source 43.

  FIG. 17 shows output voltage waveforms (R1, R2,...) Of the row electrode drive circuit 41 and output voltage waveforms (C1, C2,...) Of the column electrode drive circuit 42. The dotted line in the figure indicates that the output of the row electrode drive circuit 41 is in a high impedance state. In this embodiment, the impedance in the high impedance state is set to 5 MΩ.

At time t (1), a positive scan pulse 750 is applied to the row electrode 310R1. In this embodiment, the scan pulse amplitude Vscan is set to + 5V. At the same time, a negative voltage data pulse 760 is applied to the column electrodes 311C1 and C2. Here, the amplitude Vdata of the data pulse is set to -3V. Then, since the scanning pulse and the data pulse are superimposed and applied to the dots (1, 1) and (1, 2), a voltage of 8V is applied to the thin film electron source, and electrons are emitted. The emitted electrons are accelerated by the metal back film 112 and then collide with the phosphor 114 to excite and emit the phosphor.
At time t (2), a scanning pulse 750 is applied to the row electrode R2. At the same time, a data pulse 760 is applied to the column electrode 311C1. Then, the dot (2, 1) emits light. At time t (2), the row electrode R1 is set to a non-selection voltage in a low impedance state. Here, it was set to 0V.

In this way, any dot can be emitted by combining the scan pulse and the data pulse. In the drive waveform of FIG. 17, the shaded dots in FIG. 16 emit light. This is a standard line sequential drive method.
When all the row electrodes (that is, scanning lines) are scanned, one image is displayed. This is called a one-field period. A moving image is displayed by repeating this operation.

  One field period is divided into a “scan period” in which the scan pulse 750 is sequentially applied to the scan lines and a “non-scan period” in which the scan pulse is not applied to any of the scan lines (FIG. 25). The “scan period” defined in this specification refers to a period in which a scan pulse is applied to any one of the scan lines as shown in FIG. When the non-scanning period corresponds to the blanking period of the video signal, the consistency with the video signal is good. In this embodiment, the inversion pulse 755 is applied during the non-scanning period. As described above, since the inversion pulse has a voltage opposite to that of electron emission, electron emission does not occur and does not contribute to light emission. However, it contributes to extending the life of thin film electron sources.

  A period during which the scan pulse 750 is not applied in the scan period (in FIG. 17, for example, a period after time t (2) in the case of the row electrode R1) is a non-selection period. After applying the scanning pulse 750, the non-selected state 751 of the low impedance state is once set (time t (2)), and then the high impedance state is set (dotted line in FIG. 17, times t (3) to t (5)). Period). Thereafter, the low-impedance state non-selected state 751 is set at time t (5). Then, after the time t (6), the high impedance state is set again. Thus, in the non-selection period, the high impedance state and the low impedance state unselected state are repeated as appropriate. Accordingly, as described above, reactive power can be reduced and crosstalk can be eliminated. One method for setting n0 scanning lines in a low impedance state at an arbitrary time in the scanning period will be described below with reference to FIG. Here, the scanning period refers to a period obtained by removing a blanking period from one field period. In other words, the scanning period corresponds to a period in which scanning pulses are sequentially applied.

In the following description, the time width of the selection period in one row is 1H, and the time width is displayed in units of 1H (see FIG. 17).
After applying the scan pulse 750 to the first row electrode R1, the low impedance state is set to the non-selected state 751 for 1H. Thereafter, the low impedance non-selected state 751 is set every np [H]. The second row R2 is a waveform obtained by shifting the waveform of the first row R1 by the time of 1H. Similarly, after the third row R3, the waveform in the previous row is shifted by 1H. In this way, at any time in the scanning period, the number of row electrodes in the low impedance unselected state 751 becomes N / np. Here, N is the number of row electrodes. When combined with the number n1 of row electrodes in the selected state, the number n0 of row electrodes in the low impedance state is given by equation (7).
n0 = (N / np) + n1
become. Therefore, the following relational expression holds between the ratio of the row electrodes in the low impedance state (low impedance ratio) b = n0 / N and np.
(8) Formula

  In FIG. 17, np = 3 [H] is set to make it easy to see the setting pattern of the non-selected state 751 in the low impedance state, but in practice, for example, np = 20 [H], N = 480, and n1 = 1, b = 5.2%, and as shown in FIG. 8, the increase in reactive power can be suppressed slightly, which is preferable.

  In a display device using a combination of an electron-emitting device and a phosphor as a luminance modulation element, if the electrode in contact with the vacuum surface is set to a floating potential, abnormal discharge such as arc discharge is caused by a high voltage applied to the phosphor. There was a problem that it might trigger. This is because the floating electrode is charged by the electric charge released into the vacuum. In this embodiment, the row electrode 310 is in contact with the vacuum surface. According to the driving method of the present invention, the row electrode 310 is appropriately set in a low impedance state in one field, so that charge charging can be prevented and occurrence of abnormal discharge can be eliminated. For example, in the example of FIG. 17, the row electrode 310 is set to a low impedance state every np [H]. Thus, the present invention is particularly effective for a display device using a combination of an electron-emitting device and a phosphor as a luminance modulation device.

The preferable range of the impedance value in the high impedance state in the present invention is set as follows.
FIG. 18 is a schematic diagram in which the luminance modulation element 301, the row electrode 310, and the column electrode 311 are extracted from the display panel. The row electrode 310 corresponds to a scanning line in the display panel. The resistor R represents the output impedance of the row electrode driving circuit. In this embodiment, the luminance modulation element 301 is a combination of a thin film electron source and a phosphor.

Consider a case where there is a voltage change of amplitude ΔV at the column electrode 311. Since the current supplied from the row electrode driving circuit is limited by the resistor R, the change amount ΔVEL of the inter-terminal voltage VEL of the luminance modulation element changes according to the following equation (9).
(9) Formula ΔVEL = ΔV (1−exp [−t / τ]),
τ = RCL
Here, CL is the load capacity of the row electrode. That is, the value is the sum of the capacitance of all the luminance modulation elements connected to one row electrode to which the ΔV pulse is applied and the inter-wiring stray capacitance.

  The selection time width of one scanning line is 1H. In the case of τ = 5H, even if a voltage change of ΔV is given to the column electrode, the change amount ΔVEL of the element voltage after 1H is only 0.18 × ΔV. Since the reactive power which is a problem in the present invention is proportional to the square of (ΔVEL), it can be seen that a sufficiently low power effect can be obtained when τ = 5H.

That is, if the value of the impedance R is set so that τ ≧ 5H, the effect of the present invention can be obtained. This is the definition of the high impedance state in the present invention.
FIG. 19 shows an example of the configuration of the row electrode drive circuit 41. output is connected to each row electrode 310. When a certain row electrode is selected, when the switch circuit SW1 is connected to the selection (SEL) side, the scan pulse output from the scan pulse generation circuit is applied to the row electrode, and the selected state is obtained. On the other hand, when the row electrode is not selected, the switch circuit SW1 is connected to the non-selected (NS) side. When the switch circuit SW2 is disconnected, a high impedance state is established in which the output impedance is defined by the resistor R. On the other hand, when the switch circuit SW2 is connected, the row electrodes are in a low impedance state and not selected. In FIG. 19, V (NS, LZ) indicates a potential in a non-selected state in a low impedance state, and V (NS, HZ) indicates a potential in a non-selected state in a high impedance state.

In this embodiment, V (NS, LZ) and V (NS, HZ) are set to the ground potential.
FIG. 20 shows another example of the configuration of the row electrode drive circuit 41. In this example, a voltage limiter circuit is added to the configuration of FIG. In other words, in order to limit the potential fluctuation of the row electrode in a high impedance state to a certain range, the high level limiter potential VLH and the low level limiter potential VLL are connected via a diode. In this circuit configuration, the potential fluctuation of the row electrode in the high impedance state is limited to the range of VLH and VLL.

In this embodiment, VLH = 1V and VLL = −5V. The reason why the absolute values of the set values of VLH and VLL are different is that the luminance modulation element constituting the display panel is a unipolar device. That is, in this embodiment, since the row electrode changes to a positive potential in the forward direction, it may cause display crosstalk, so the potential change tolerance is small. On the other hand, since the change of the row electrode to the negative potential is the change of the reverse polarity, display crosstalk is not caused. Therefore, the potential fluctuation tolerance on the negative voltage side is large.
As will be described later, when the voltage limiter circuit is activated, the scanning line becomes low impedance, so that the low power effect is temporarily reduced. Therefore, in order to maximize the low power effect, it is preferable that the allowable voltage range of the voltage limiter be as large as possible and the limiter not be operated. In the present invention, the allowable voltage in the reverse polarity direction is set to be large by utilizing the unipolar characteristics of the luminance modulation element, and this is realized.
Alternatively, the voltage limiter may be set only on the forward polarity voltage side of the luminance modulation element, and the limiter may not be provided on the reverse polarity voltage side. For example, in accordance with the present embodiment, in FIG. 20, only the VLH side limiter circuit may be provided, and the VLL side limiter circuit may not be provided.

By using the voltage limiter circuit in this way, it is possible to further stabilize the display image.
When the induced voltage of the row electrode exceeds the limiter voltage and the limiter circuit is activated, the row electrode becomes low impedance. As an example, consider the case in FIG. 17 where the limiter voltage exceeds the induced potential of the row electrode 310R1 at time t (6). Then, at time t (6), the row electrode 310R1 has a low impedance through the limiter circuit, so that the power reduction effect is temporarily reduced. However, since it is set to the low impedance non-selected state 751 at time t (8), it is pulled back into the limiter voltage range. Therefore, after time t (9), the state again returns to the high impedance state.

  A third embodiment of the present invention will be described with reference to FIGS. 21, 22, 23, and 24. FIG. The image display apparatus of the third embodiment uses a display panel in which a luminance modulation element of each dot is formed by a combination of a thin film electron source matrix, which is an electron emission electron source, and a phosphor. A drive circuit is connected to the column electrode.

In this embodiment, some of the row electrodes also function as the spacer electrode 315. A row electrode that also functions as a spacer electrode is referred to as a spacer-installed row electrode 316. That is, as shown in FIGS. 21 and 22, the spacer 60 is installed on the spacer installation row electrode 316. The shape and configuration of the spacer-installed row electrode 316 may be the same as the other row electrodes 310. In FIG. 21, the spacer 60 is installed in a dotted line part.
As in the second embodiment, the spacer 60 is prevented from being charged by imparting appropriate conductivity to the spacer 60.

The display panel described in this embodiment can be manufactured by the same method as in the second embodiment.
FIG. 23 is a diagram showing a method of connecting the display panel and the drive circuit of this embodiment. The spacer-installed row electrode 316 is connected to the row electrode drive circuit 41 in the same manner as the other row electrodes.

  FIG. 24 shows output voltage waveforms (R1, R2,...) Of the row electrode drive circuit 41 and output voltage waveforms (C1, C2,...) Of the column electrode drive circuit 42. The dotted line in the figure indicates that the output of the row electrode drive circuit 41 is in a high impedance state. In this embodiment, the impedance in the high impedance state is set to 5 MΩ.

  In this embodiment, the spacer-installed row electrode 316 (R3) is always set to the non-selected state 751 in the low impedance state during the image display operation. Since a high voltage is applied to the metal back film 122, a minute leak current flows to the spacer-installed row electrode 316 through the spacer 60 imparted with appropriate conductivity. This prevents the spacer from withstanding electricity and keeps the electric field around the spacer uniform.

The conductivity of the spacer 60 is sufficient as long as it prevents the spacer from withstanding electricity, and a slight conductivity is sufficient. Therefore, the resistance value of the spacer is set sufficiently higher than the output impedance of the row electrode drive circuit 41. Therefore, the scanning pulse 750 can be applied to the spacer-installed row electrode 316 as well.
In the display panel, the number of spacer-installed row electrodes 316 is ns. Then the number of low impedance scan lines at any time during the scan period is:
(10) Formula
n0 = (N / np) + n1 + ns
become. Here, the definitions of the symbols N, n0 and n1 are the same as those described above. Therefore, the following relational expression holds between the ratio of the row electrodes in the low impedance state (low impedance ratio) b = n0 / N and np.
(11) Formula

In FIG. 24, np = 3 [H] is set in order to make the setting pattern of the non-selected state 751 in the low impedance state easy to see, but actually, for example, np = 20 [H]. Assuming that the number of spacer-installed row electrodes 316 is nS = 10, N = 480, and n1 = 1, then b = 7.3%. Therefore, as shown in FIG. .

  In the above description, an image display device in which a thin film electron source and a phosphor are combined as a luminance modulation element has been described. It is obvious that the present invention can be applied to an image display device using other unipolar luminance modulation elements.

DESCRIPTION OF SYMBOLS 10 ... Vacuum, 11 ... Upper electrode, 12 ... Tunnel insulating layer, 13 ... Lower electrode, 14, 110 ... Substrate, 15 ... Protective insulating layer, 32 ... Upper electrode bus line, 35 ... Electron emission part, 41 ... Row electrode drive Circuits 42... Column electrode driving circuit 43... Acceleration voltage source 60. Spacer 114 A. Red phosphor 114 B Green phosphor 114 C Blue phosphor 120 Black matrix 122 Metal back film 301 Luminance modulation element, 310... Row electrode, 311... Column electrode, 750... Scan pulse, 751 .. non-selection state in low impedance state, 755.
315... Spacer electrode, 316.

Claims (16)

Modulated luminance in the positive polarity voltage application, and has a plurality of luminance modulation element without intensity modulation at a voltage application of a reverse polarity, the display having a plurality of scanning electrodes are parallel to each other, and a plurality of parallel data electrodes to each other In the image display device having a panel, a first drive unit connected to the plurality of scan electrodes and outputting a scan pulse, and a second drive unit connected to the plurality of data electrodes, the scan electrode includes: At least three states are set: a selected state to which a scan pulse is applied, a non-selected state in a high impedance state, and a non-selected state in a low impedance state, and the unselected scanning line in the low impedance state is set in the high impedance state. The non-selected state is a lower impedance state than the scanning line, and the low-impedance state non-selected state and the high-impedance state unselected state Status and are repeated alternately,
The first driving means enters a low impedance state when the potential of the scanning electrode in the non-selected state exceeds a preset voltage range, and keeps the potential of the scanning electrode within the set voltage range. An image display device comprising means. The predetermined voltage range is characterized in that an absolute value of a setting voltage on the reverse polarity side of the luminance modulation element is set larger than an absolute value of a setting voltage on the positive polarity side of the luminance modulation element. 2. The image display device according to 1. A display having a plurality of luminance modulation elements whose luminance is modulated by applying a positive polarity voltage and not modulated by applying a reverse polarity voltage, and having a plurality of scanning electrodes parallel to each other and a plurality of data electrodes parallel to each other In the image display device having a panel, a first drive unit connected to the plurality of scan electrodes and outputting a scan pulse, and a second drive unit connected to the plurality of data electrodes, the scan electrode includes: At least three states are set: a selected state to which a scan pulse is applied, a non-selected state in a high impedance state, and a non-selected state in a low impedance state, and the unselected scanning line in the low impedance state is set in the high impedance state. The non-selected state is a lower impedance state than the scanning line, and the low-impedance state non-selected state and the high-impedance state unselected state Status and are repeated alternately,
At the same time, the number of the scanning electrodes in the selected state is n1, the number of the scanning electrodes is N, and the average period in which the low impedance state non-selected state and the high impedance state non-selected state are repeated is np [H ], An image display device satisfying the following expression:
(1 / np) + (n1 / N) ≦ 0.1 4. The image display device according to claim 1, wherein an image display operation is performed by a line sequential driving method. When the capacitance of the scanning electrode is CL, the output impedance of the first driving means when the high impedance state is set to the non-selected state is Z, and the time width of the selection period of one scanning line is H , Z × CL> 5 × H is satisfied, The image display device according to claim 1 . The image display apparatus according to any one of claims 1 to 5 impedance of the non-selected state scanning lines of the high impedance state is characterized by a higher 1 M.OMEGA. The image display apparatus according to any one of claims 1 to 6, wherein the organic light emitting diode as the luminance modulation element. It has a plurality of luminance modulation elements composed of a combination of an electron-emitting device and a phosphor, and has a plurality of scan electrodes parallel to each other and a plurality of data electrodes parallel to each other, and is connected to the plurality of scan electrodes. In an image display device having a first driving means for outputting a scanning pulse and a second driving means connected to the plurality of data electrodes, the scanning electrode has a selected state to which a scanning pulse is applied, and a high state. There are at least three states, a non-selected state of impedance state and a non-selected state of low impedance, and the non-selected state scanning line in the low impedance state has a lower impedance state than the non-selected state scanning line in the high impedance state. And the non-selected state of the low impedance state and the non-selected state of the high impedance state are alternately repeated,
The first driving means enters a low impedance state when the potential of the scanning electrode in the non-selected state exceeds a preset voltage range, and keeps the potential of the scanning electrode within the set voltage range. An image display device having means. The predetermined voltage range is characterized in that an absolute value of a setting voltage on the reverse polarity side of the luminance modulation element is set larger than an absolute value of a setting voltage on the positive polarity side of the luminance modulation element. 8. The image display device according to 8 . It has a plurality of luminance modulation elements composed of a combination of an electron-emitting device and a phosphor, and has a plurality of scan electrodes parallel to each other and a plurality of data electrodes parallel to each other, and is connected to the plurality of scan electrodes. In an image display device having a first driving means for outputting a scanning pulse and a second driving means connected to the plurality of data electrodes, the scanning electrode has a selected state to which a scanning pulse is applied, and a high state. There are at least three states, a non-selected state of impedance state and a non-selected state of low impedance, and the non-selected state scanning line in the low impedance state has a lower impedance state than the non-selected state scanning line in the high impedance state. And the non-selected state of the low impedance state and the non-selected state of the high impedance state are alternately repeated,
At the same time, the number of the scanning electrodes in the selected state is n1, the number of the scanning electrodes is N, and the average period in which the low impedance state non-selected state and the high impedance state non-selected state are repeated is np [H ], An image display device satisfying the following expression:
(1 / np) + (n1 / N) ≦ 0.1 It has a plurality of luminance modulation elements composed of a combination of an electron-emitting device and a phosphor, and has a plurality of scan electrodes parallel to each other and a plurality of data electrodes parallel to each other, and is connected to the plurality of scan electrodes. In an image display device having a first driving means for outputting a scanning pulse and a second driving means connected to the plurality of data electrodes, the scanning electrode has a selected state to which a scanning pulse is applied, and a high state. There are at least three states, a non-selected state of impedance state and a non-selected state of low impedance, and the non-selected state scanning line in the low impedance state has a lower impedance state than the non-selected state scanning line in the high impedance state. And the non-selected state of the low impedance state and the non-selected state of the high impedance state are alternately repeated,
Some of the scanning electrodes are in contact with a spacer, and the scanning electrode in contact with the spacer is always set in a low impedance state during a display operation period. It has a plurality of luminance modulation elements composed of a combination of an electron-emitting device and a phosphor, and has a plurality of scan electrodes parallel to each other and a plurality of data electrodes parallel to each other, and is connected to the plurality of scan electrodes. In an image display device having a first driving means for outputting a scanning pulse and a second driving means connected to the plurality of data electrodes, the scanning electrode has a selected state to which a scanning pulse is applied, and a high state. There are at least three states, a non-selected state of impedance state and a non-selected state of low impedance, and the non-selected state scanning line in the low impedance state has a lower impedance state than the non-selected state scanning line in the high impedance state. And the non-selected state of the low impedance state and the non-selected state of the high impedance state are alternately repeated,
At the same time, the number of scan electrodes in the selected state is n1, the number of scan electrodes is N, the number of scan electrodes in contact with the spacer is ns, the low-impedance state non-selected state and the high-impedance state An image display device characterized by satisfying the following expression, where np [H] is an average period in which the non-selected state is repeated.
(1 / np) + (n1 + ns) /N≦0.1 The image display device according to claim 8, wherein the image display operation is performed by a line sequential driving method. When the capacitance of the scanning electrode is CL, the output impedance of the first driving means when the high impedance state is set to the non-selected state is Z, and the time width of the selection period of one scanning line is H , Z × CL> 5 × H is satisfied, The image display device according to claim 8 . 15. The image display device according to claim 8, wherein the scanning electrode is formed on a side closer to a vacuum than the data electrode. The image display device according to claim 8, wherein the scanning electrode is in contact with a vacuum.

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