JP4866028B2 - Field emission display and driving method thereof - Google Patents

Description

  The present invention relates to a field emission display and a driving method thereof, and more particularly to a field emission display that vibrates an electron beam and a driving method thereof.

  As a cold cathode of a field emission display, a cold cathode having a cold cathode emitter made of a carbon-based material, a spin cathode cold cathode, a SCE (Surface Conduction Electron emitter) cold cathode, and the like have been studied. In addition, as a carbon-based material, CNT (Carbon Nanotube), GNF (Graphite Nanofiber), DLC (Diamond Like Carbon) and the like have been evaluated.

  However, since the cold cathode has a fine shape, it is difficult to manufacture a plurality of cold cathodes in a uniform shape. For this reason, the electron emission characteristics between the cold cathodes are different due to the variation in the shape between the cold cathodes, and there is a problem that the luminance varies and flickers between the pixels, thereby degrading the image quality.

In order to solve such a problem, a method in which the luminance of each pixel is measured in advance and the difference is superimposed on the image signal (see, for example, Patent Document 1), the number of cold cathodes in the pixel is increased, and cooling is performed. A method of averaging the amount of electron emission of the cathode, a method of arranging FET (Field Effect Transistor) in series in each pixel, and controlling a current flowing through the cold cathode emitter (for example, refer to Patent Document 2), a cathode electrode and A method of limiting a current by providing a resistor between a cold cathode or a power source (for example, see Patent Document 3) has been studied.
JP 2003-248452 A JP 2002-244588 A JP 2001-250469 A

  However, when the field emission display has a high definition, the size of the pixel tends to be small, and it is difficult to form a large number of cold cathodes in one subpixel. For this reason, there has been a problem that high-quality images cannot be obtained due to luminance variations and flickering between pixels.

  In addition, when a field emission display with a large screen is made high-definition, it is difficult to provide a large number of FETs and TFTs for each small pixel, and variations in luminance and flicker between pixels cannot be compensated, resulting in a high-quality image. There was a problem that could not get.

  Accordingly, the present invention has been made in view of the above-described problems, and a field emission display capable of obtaining a high-quality image by suppressing luminance variation and flicker between pixels on a high-definition screen, and An object is to provide a driving method thereof.

According to one aspect of the present invention, a field emission type including a front plate having a phosphor, and a back plate having a cold cathode composed of a plurality of electrodes stacked via an insulating layer and a cold cathode emitter. In the display, an electrode closest to the front plate among the plurality of stacked electrodes is divided into a plurality of strip electrodes, and a predetermined pulse voltage is applied to at least three strip electrodes among the plurality of strip electrodes. A function of vibrating an electron beam emitted from the cold cathode; input image data based on a luminance level of an adjacent pixel; first image data in which an image is displayed by vibrating the electron beam; There is provided a field emission display provided with data processing means for dividing the electron beam into second image data on which an image is displayed without vibrating the electron beam .

  According to the present invention, among the stacked electrodes, the electrode closest to the front plate is divided into a plurality of strip electrodes, and a predetermined pulse voltage is applied to at least three strip electrodes among the plurality of strip electrodes. By oscillating the electron beam emitted from the cold cathode, the number of cold cathodes that emit electrons to the phosphor corresponding to each pixel is increased, thereby suppressing luminance variation and flicker between pixels, A quality image can be obtained.

According to another aspect of the present invention, a field emission comprising a front plate having a phosphor, and a back plate having a cold cathode comprised of a plurality of electrodes and a cold cathode emitter laminated via an insulating layer. In the method for driving a flat panel display, among the plurality of electrodes, an electrode closest to the front plate is divided into a plurality of strip electrodes, and among the plurality of strip electrodes, a strip electrode corresponding to a cold cathode that should emit an electron beam A first voltage applied to a strip electrode on one side including at least an electrode adjacent to the strip, and a strip on the other side including at least an electrode adjacent to the strip electrode corresponding to the cold cathode from which the electron beam is to be emitted. the magnitude relation between the second voltage and applying the voltage to switch to the time applied to the electrode has a function for vibrating the electron beam, by the data processing means, the input image data, the adjacent image The first image data in which an image is displayed by vibrating the electron beam and the second image data in which an image is displayed without vibrating the electron beam are divided on the basis of the luminance level of the first image. There is provided a method for driving a field emission display, wherein the electron beam is vibrated when displaying data, and the electron beam is not vibrated when displaying the second image data .

  According to the present invention, among the plurality of electrodes, the electrode closest to the front plate is divided into a plurality of strip electrodes, and the plurality of strip electrodes are adjacent to the strip electrode corresponding to the cold cathode from which the electron beam is to be emitted. A first voltage applied to a strip electrode on one side including at least an electrode, and a strip electrode corresponding to a cold cathode from which an electron beam is to be emitted and a strip electrode on the other side including at least an adjacent electrode on the other side A voltage is applied so that the magnitude relationship with the second voltage is switched over time, and the electron beam is oscillated to increase the number of cold cathodes that emit electrons to the phosphor corresponding to each pixel. High-quality images can be obtained by suppressing variations in brightness and flicker.

  According to the present invention, high-quality images can be obtained on a high-definition screen by reducing variations in luminance and flicker between pixels.

  Next, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a perspective view showing an outline of a field emission display according to a first embodiment of the present invention. In FIG. 1, A is a pixel composed of three sub-pill cells (hereinafter referred to as “pixel A”), B _{1 to} B _n are scanning lines (hereinafter referred to as “scanning lines B _{1 to} B _n ”), X , X direction indicates the longitudinal direction of the scanning lines B _{1 to} B _n , and Y and Y directions indicate directions orthogonal to the scanning lines B _{1 to} B _n , respectively.

As shown in FIG. 1, the field emission display 10 has n (n is a natural number) scanning lines B _{1 to} B _n , and includes a front plate 11, a back plate 12, a data driver 13, and scanning. The configuration includes a driver 14, a control device 15, and a data input terminal 16.

  The front plate 11 includes a substrate 17, an anode electrode 18, and a phosphor 19. The anode electrode 18 is provided so as to cover the lower surface 17A of the substrate 17 (the surface of the substrate 17 facing the back plate 12). The phosphor 19 is provided so as to cover the anode electrode 18. The phosphor 19 includes a plurality of red phosphors 19A, a green phosphor 19B, and a blue phosphor 19C. The plurality of red phosphors 19A, green phosphors 19B, and blue phosphors 19C are arranged in the order of red phosphors 19A, green phosphors 19B, and blue phosphors 19C in the X and X directions. .

The back plate 12 includes a substrate 21, m (m is a natural number) cathode electrodes 23 ₁ to 23 _m , an insulating layer 24, n (n is a natural number) gate electrodes 25 _{1 to} 25 _n , And a cold cathode 27. The cathode electrodes 23 ₁ to 23 _m and the gate electrodes 25 _{1 to} 25 _n are a plurality of stacked electrodes.

The cathode electrodes 23 ₁ to 23 _m are strip-shaped electrodes, and are provided on the upper surface 21A of the substrate 21 so that the longitudinal direction thereof is the Y and Y directions. The cathode electrodes 23 ₁ to 23 _m are connected to the data driver 13 and are applied with data voltage pulses. The insulating layer 24 is provided on the upper surface 21A of the substrate 21 so as to cover the cathode electrodes 23 ₁ to 23 _m .

The gate electrodes 25 _{1 to} 25 _n are _n electrodes in a band shape, and are arranged at a position closest to the front plate 11 among the plurality of stacked electrodes. The gate electrodes 25 _{1 to} 25 _n are provided on the insulating layer 24 so that the longitudinal directions thereof are the X and X directions (so as to be orthogonal to the cathode electrodes 23 ₁ to 23 _m ). The gate electrodes 25 _{1 to} 25 _n are connected to the scanning driver 14 and are configured to be able to change the voltage (predetermined voltage) applied to each of the gate electrodes 25 _{1 to} 25 _n . A plurality of cold cathodes 27 are provided in a region F where the gate electrodes 25 _{1 to} 25 _n and the cathode electrodes 23 ₁ to 23 _m are orthogonal to each other.

  FIG. 2 is a cross-sectional view of the cold cathode of the present embodiment. As shown in FIG. 2, the cold cathode 27 is provided on the substrate 21, and includes a cathode electrode 23, an insulating layer 24, a gate electrode 25, and a cold cathode emitter 29. An opening 28 exposing the cathode electrode 23 is formed in the insulating layer 24 and the gate electrode 25. The cold cathode emitter 29 is provided on the cathode electrode 23 exposed in the opening 28. The cold cathode emitter 29 is for emitting electrons.

3 and 4 are diagrams schematically showing a cross-sectional view of a field emission display when an electron beam is deflected. In FIGS. 3 and 4, the voltage VG _k-1 applied to the gate electrode 25 _{k-1 (k} is 2 ≦ k a natural number of ≦ n-1), the voltage applied to the gate electrode 25 _k VG _k, gate The following description will be made assuming that the voltage applied to the electrode 25 _{k + 1} is VG _{k + 1} .

Here, with reference to FIG. 3 and FIG. 4, the method of deflecting the electron beam E will be described by taking as an example the case of deflecting the electron beam E from the cold cathode 27 _k corresponding to the gate electrode 25 _k .

As shown in FIG. 3, when the electron beam E emitted from the cold cathode 27 _k is deflected to the gate electrode 25 _k-1 side (the upper side of the field emission display 10), the cold cathode from which the electron beam E is to be emitted. with 27 voltage to the gate electrode 25 _k corresponding to _k VG _k applies the (electron voltage to release), the voltage VG _k-1 (the gate electrode 25 _k-1 adjacent to the gate electrode 25 _k on one side a first voltage) is applied a voltage VG k _{+ 1} (second voltage) to the gate electrode 25 k _{+ 1} adjacent to the gate electrode 25 _k on the other side. The voltages VG _k−1 and VG _{k + 1} are voltages that satisfy VG _k > VG _k−1 > VG _{k + 1} .

Thus, the gate electrode 25 _k-1 adjacent to and on both sides of the gate electrode 25 _k, 25 _{k + 1} to _{VG k> VG k-1>} VG k + 1 become such a voltage VG _k-1, VG _{k +} By applying ₁ , an equipotential line D1 as shown in FIG. 3 can be formed, and the electron beam E emitted from the cold cathode 27 _k can be deflected to the gate electrode 25 _k−1 side.

As shown in FIG. 4, when the electron beam E emitted from the cold cathode 27 _k is deflected to the gate electrode 25 _{k + 1} side (the lower side of the field emission display 10), the electron beam E should be emitted. with voltage VG _k to the gate electrode 25 _k corresponding to the cold cathode 27 _k applies the (electron voltage to release), the voltage VG _k-1 to the gate electrode 25 _k-1 adjacent to the gate electrode 25 _k on one side (first voltage) is applied a voltage VG k _{+ 1} (second voltage) to the gate electrode 25 k _{+ 1} adjacent to the gate electrode 25 _k on the other side. The voltages VG _k−1 and VG _{k + 1} are voltages that satisfy VG _k > VG _{k + 1} > VG _k−1 .

Thus, the gate electrode _{25 k-1, 25 k +} 1 to _{VG k> VG k + 1>} VG k-1 to become such a voltage _{VG k-1, VG k +} 1 adjacent to the gate electrode 25 _k By applying, an equipotential line D2 as shown in FIG. 4 can be formed and the electron beam E emitted from the cold cathode 27 _k can be deflected to the gate electrode 25 _{k + 1} side.

In addition, by applying a voltage so that the magnitude relationship between the voltages VG _k-1 and VG _{k + 1} applied to the gate electrodes 25 _k-1 and 25 _{k + 1} is temporally switched, it corresponds to the gate electrode 25 _k . The electron beam E emitted from the cold cathode 27 _k can be oscillated in the Y and Y directions of the field emission display 10.

In this way, the voltage VG _k (voltage at which electrons are emitted) is applied to the gate electrode 25 _k corresponding to the cold cathode 27 _k to which the electron beam E is to be emitted, and the adjacent gate electrode 25 _k-1 on one side. voltage applied to the VG _k-1 (first voltage), the magnitude relationship between the voltage VG k _{+ 1} is applied to the gate electrode 25 k _{+ 1} on the other side adjacent to the gate electrode 25 _k (second voltage) By applying a voltage so as to switch over time, the number of cold cathodes 27 that emit electrons to the phosphors 19 corresponding to each pixel A can be increased. As a result, the influence of the electron emission characteristics of the cold cathode emitters 29 on the image can be reduced, and a high-quality image in which luminance variations and flickering between the pixels A are suppressed can be obtained.

3 and 4, the voltage is applied only to the gate electrodes 25 _k-1 and 25 _{k + 1} adjacent to both sides of the gate electrode 25 _k corresponding to the cold cathode 27 _k that should emit the electron beam E. has been described as an example, the gate electrode 25 _k-1 adjacent to and on both sides of the gate electrode 25 _k, 25 _k + ₁ may apply a voltage to the plurality of gate electrodes, including a. That is, by applying a voltage VG _k-1 of the gate electrode 25 _k-1 to a gate electrode of at least including one side adjacent to the gate electrode 25 _k corresponding to the cold cathode 27 _k should be released electron beam E, the gate electrode 25 _k and the gate electrode 25 k _{+ 1} adjacent on the other may be applied a voltage VG k _{+ 1} to a gate electrode of at least including the other side. In short, equipotential lines D1 and D2 as shown in FIGS. 3 and 4 may be formed. In this case as well, adjacent to both sides of the gate electrode 25 _k corresponding to the cold cathode 27 _{k from} which the electron beam E should be emitted. It is possible to obtain the same effect as when a voltage is applied only to the gate electrodes 25 _k-1 and 25 _{k + 1} .

Next, the data driver 13 will be described with reference to FIG. The data driver 13 has m drive circuits (not shown), and each drive circuit is connected to any one of the cathode electrodes 23 ₁ to 23 _m . The data driver 13 is connected to the control device 15 and applies a voltage to the cathode electrodes 23 ₁ to 23 _m based on a control signal from the control device 15.

The scanning driver 14 has n drive circuits (not shown), and each drive circuit is connected to any one of the gate electrodes 25 _{1 to} 25 _n . The scanning driver 14 is connected to the control device 15 and applies a voltage to the gate electrodes 25 _{1 to} 25 _n based on a control signal from the control device 15.

  The control device 15 performs overall control of the field emission display 10 and has a data processing means 30. The control device 15 controls the data driver 13 and the scanning driver 14 by a control signal. The data input terminal 16 is a terminal for receiving input image data a from the outside.

  Here, the relationship between the luminance level of the display image and the resolution will be described. In the display image, in the image forming area where the change in the luminance level is small, the influence of the visibility due to the luminance variation and the flickering is large, but the influence of the visibility due to the deterioration of the resolution is small. On the other hand, in the image region where the change in the luminance level is large, the influence of the visibility due to the luminance variation and the flickering is small, but the influence of the visibility due to the deterioration of the resolution is large.

  The data processing means 30 is connected to the data input terminal 16 and the data driver 13. The data processing means 30 is based on the threshold value G of the difference between the luminance levels of the adjacent pixels that have been inputted in advance with the input image data a from the data input terminal 16, and the data processing means 30 The first image data and the second image data are transmitted to the data driver 13 separately for one image data and the second image data in the region where the luminance level of the adjacent pixel A is greatly changed. The data processing means 30 sets the first image data when the luminance level of the adjacent pixel A is smaller than the threshold value G of the difference between the luminance levels inputted in advance, and the threshold value inputted with the luminance level of the adjacent pixel A beforehand. When it is larger than G, it is set as the second image data. The electron beam E is vibrated when displaying the first image data, and the electron beam E is not vibrated when displaying the second image data.

  In this way, the data processing means that divides the input image data a into the first image data in the region where the change in the luminance level is small and the second image data in the region where the change in the luminance level is large based on the threshold value G inputted in advance. 30, the first image data is displayed by vibrating the electron beam E, and the second image data is displayed without vibrating the electron beam E, so that the resolution of the display image by vibrating the electron beam E is improved. Deterioration can be suppressed. Note that an optimal value can be appropriately selected as the threshold value G input in advance according to the performance of the display.

FIG. 5 is a diagram showing an example of a driving waveform of the field emission display according to the present embodiment. 5, (a) shows the waveform of the voltage pulse applied to the gate electrodes 25 _{1 to} 25 _k−1 , (b) shows the waveform of the voltage pulse applied to the gate electrode 25 _k , and (c) shows the gate electrode 25 _{k +.} The waveform of the voltage pulse applied to ₁ and (d) show the waveform of the voltage pulse applied to the gate electrodes 25 _{k + 2 to} 25 _n , respectively.

Next, a method for driving the field emission display 10 will be described with reference to FIG. 5, taking as an example the case of scanning the scanning line B _k (k is a natural number of 1 ≦ k ≦ n).

  In the field emission display 10 of the present embodiment, one horizontal scanning period (1H) is divided into two periods, and an image is displayed by vibrating the electron beam E using the first half H / 2 period. An image is displayed using a method in which the electron beam E is not vibrated using the second half H / 2 period.

Specifically, at time t ₁ , the voltage V _GE (voltage value at which electrons are emitted) is applied to the gate electrode 25 _k corresponding to the scanning line B _k , the voltage V _GS is applied to the gate electrodes 25 _{1 to} 25 _k−1. A voltage V _G0 is applied to each of the electrodes 25 _{k + 1 to} 25 _n (V _GE > V _G0 > V _GS ). Accordingly, equipotential line D2 as described with reference to FIG preceding is formed, the electron beam E emitted from the cold cathode 27 _k is deflected to the cold cathode 27 _{k + 1} side.

Next, at time t ₂ Oite, voltage V _G0 to the gate electrode 25 ₁ ~25 _k-1, respectively applied the voltage V _GS to the gate electrode 25 _k + 1 ~25 _n. Accordingly, the equipotential lines D1 as described in FIG. 3 former is formed, the electron beam E emitted from the cold cathode 27 _k is deflected to the cold cathode 27 _k-1 side. In the first half H / 2 period (between times t _{1 and} t ₃ ), a data voltage pulse corresponding to the first image data is applied to the cathode electrodes 23 ₁ to 23 _m .

In this way, in the first half of the horizontal scanning period (1H) of H / 2 (between times t _{1 and} t ₃ ), the gate electrodes 25 _{1 to} 25 _k−1 and the gate electrodes 25 _{k + 1 to} 25 _n Are applied with a voltage pulse (voltage pulse for electron beam deflection) whose phase is shifted by half a wavelength, and a data voltage pulse corresponding to the first image data is applied to the cathode electrodes 23 ₁ to 23 _m . The first image data with a small change in luminance level can be displayed by vibrating E. Note that the number of voltage pulses applied to the gate electrodes 25 _{1 to} 25 _k-1 and the gate electrodes 25 _{k + 1 to} 25 _n in the first half H / 2 period may be one or more. The form is not limited.

Next, at time t ₃ , the voltage V _G0 is applied to the gate electrodes 25 _{k + 1 to} 25 _n , and the electron beam E oscillates in the latter H / 2 period (between times t _{3 and} t ₄ ). The second image data having a large change in luminance level is displayed. At this time, a data voltage pulse corresponding to the second image data is applied to the cathode electrodes 23 ₁ to 23 _m in the latter H / 2 period (between times t _{3 and} t ₄ ).

Even when the scanning line B _{k + 1} is scanned in one horizontal scanning period from time t _{4 to} time t ₆ , scanning can be performed by the same method as that for the scanning line B _k . Further, the other scanning lines B _{1 to} B _k−1 and B _{k + 2 to} B _n can be scanned by the same method as the scanning line B _k . The voltage V _G0 can be set to 0 V, for example.

  According to the present embodiment, one horizontal scanning period (1H) is divided into two, and the first image data is displayed by vibrating the electron beam E using the first half H / 2 period. By displaying the second image data without oscillating the electron beam E using the period of / 2, the number of cold cathodes 27 that emit electrons to the phosphors 19 corresponding to each pixel A is increased, It is possible to reduce the influence of the electron emission characteristics of the cathode emitter 29 on the image, suppress degradation of the resolution of the display image, and display a high-quality image.

(Second Embodiment)
FIG. 6 is a perspective view showing an outline of a field emission display according to the second embodiment of the present invention. In FIG. 6, the same components as those of the field emission display 10 according to the first embodiment are denoted by the same reference numerals.

As shown in FIG. 6, the field emission display 40 has n scanning lines B _{1 to} B _n , and includes a front plate 11, a data driver 13, a scanning driver 14, a control device 15, The data input terminal 16, the back plate 41, and the focus electrode driver 46 are provided.

The back plate 41 includes a substrate 21, m cathode electrodes 23 ₁ to 23 _m , insulating layers 24 and 42, n gate electrodes 25 _{1 to} 25 _n , and n focus electrodes 43 ₁ to 43 _n. And a plurality of cold cathodes 45. That is, the back plate 41 has a configuration in which the insulating layer 42 and the focus electrodes 43 ₁ to 43 _n are further provided in the configuration of the back plate 12 of the first embodiment, and the cold cathode 45 is provided instead of the cold cathode 27. It is said that.

The cathode electrodes 23 ₁ to 23 _m , the gate electrodes 25 _{1 to} 25 _n , and the n focus electrodes 43 ₁ to 43 _n are a plurality of stacked electrodes. The insulating layer 42 is provided on the insulating layer 24 so as to cover the gate electrodes 25 _{1 to} 25 _n .

The focus electrodes 43 ₁ to 43 _n are _n electrodes formed in a band shape, and are arranged at a position closest to the front plate 11 among the plurality of stacked electrodes. The longitudinal directions of the focus electrodes 43 ₁ to 43 _n are the X and X directions, and are provided on the insulating layer 42 so as to face the gate electrodes 25 _{1 to} 25 _n .

The focus electrodes 43 ₁ to 43 _n are connected to a focus electrode driver 46, and are configured such that a voltage can be applied to the focus electrodes 43 ₁ to 43 _n by the focus electrode driver 46. The focus electrodes 43 ₁ to 43 _n are electrodes for focusing the electron beam E.

A plurality of cold cathodes 45 are provided in a region J where the gate electrodes 25 _{1 to} 25 _n and the focus electrodes 43 ₁ to 43 _n and the cathode electrodes 23 ₁ to 23 _m are orthogonal to each other.

  FIG. 7 is a cross-sectional view of the cold cathode of the present embodiment. As shown in FIG. 7, the cold cathode 45 is provided on the substrate 21, and includes a cathode electrode 23, insulating layers 24 and 42, a gate electrode 25, a cold cathode emitter 29, and a focus electrode 43. Has been. The insulating layers 24 and 42, the gate electrode 25, and the focus electrode 43 have an opening 48 that exposes the cathode electrode 23.

As shown in FIG. 6, the focus electrode driver 46 has n drive circuits, and each drive circuit is connected to any one of the focus electrodes 43 ₁ to 43 _n . The focus electrode driver 46 is connected to the control device 15 and applies a voltage to each of the focus electrodes 43 ₁ to 43 _n based on a control signal from the control device 15.

FIG. 8 and FIG. 9 are diagrams schematically showing cross-sectional views of the field emission display when the electron beam is deflected. 8 and 9, the focusing electrode 43 _{k-1 (k} is 1 ≦ k a natural number of ≦ n) the voltage applied to the VF _k-1, the voltage applied to the focus electrode 43 _k VF _k, the focus electrode 43 _{k The} following description will be made assuming that the voltage applied to ₊₁ is VF _{k + 1} .

Next, a method for deflecting the electron beam E will be described with reference to FIGS. 8 and 9 by taking as an example the case of deflecting the electron beam E emitted from the cold cathode 45 _k corresponding to the focus electrode 43 _k .

As shown in FIG. 8, when the electron beam E emitted from the cold cathode 45 _k is deflected to the focus electrode 43 _k-1 side (above the field emission display 40), the electron beam is applied to the focus electrode 43 _k. E together applies a voltage VF _k focusing, voltage to the focus electrode 43 _k-1 and the adjacent focus electrode 43 _k on one side VF _k-1 (first voltage), the focusing electrode 43 _k on the other side And a voltage VF _{k + 1} (second voltage) smaller than the voltage VF _{k- 1} is applied to the adjacent focus electrode 43 _{k + 1} .

Thus, with the focus electrode 43 _k electron beam E applies a voltage VF _k focusing, VF _k-1 to the focus electrode _{43 k-1, 43 k +} 1 adjacent to the focus electrode 43 _k> VF _{k +} by applying a voltage _{VF k-1, VF k +} 1 to be _1, to form an equipotential line D3 as shown in FIG. 8, with focusing the emitted electron beams E from the cold cathode 45 _k, The focused electron beam E can be deflected to the focus electrode 43 _k-1 side.

In this case, the voltages VF _k−1 and VF _{k + 1} applied to the focus electrodes 43 _k−1 and 43 _{k + 1} are set so as to satisfy the relationship of VF _k−1 > VF _k > VF _{k + 1.} Good. Thus, by making the voltage VF _k-1 larger than the voltage VF _k , it is possible to easily deflect the electron beam E emitted from the cold cathode 45 _k .

As shown in FIG. 9, when the electron beam E emitted from the cold cathode 45 _k is deflected to the focus electrode 43 _{k + 1} side (the lower side of the field emission display 40), the electron beam is applied to the focus electrode 43 _k. E together applies a voltage VF _k focusing, voltage to the focus electrode 43 _k-1 and the adjacent focus electrode 43 _k on one side VF _k-1 (first voltage), the focusing electrode 43 _k on the other side A voltage VF _{k + 1} (second voltage) larger than the voltage VF _{k- 1} is applied to the focus electrode 43 _{k + 1} adjacent to the _first electrode.

Thus, voltage VF _k and the focus electrode _{43 k-1, 43 k +} 1 to _{VF k-1 <VF k +} 1 become such a voltage VF _k-1 for focusing an electron beam E in the focus electrode 43 _k , VF _{k + 1} is applied to form an equipotential line D4 as shown in FIG. 9, and the electron beam E emitted from the cold cathode 45 _k is focused and the focused electron beam E is It can be deflected to the focus electrode 43 _{k + 1} side.

In this case, the voltages VF _k−1 and VF _{k + 1} applied to the focus electrodes 43 _k−1 and 43 _{k + 1} are set so as to satisfy the relationship of VF _{k + 1} > VF _k > VF _k−1. Good. Thus, by making the voltage VF _{k + 1} larger than the voltage VF _k , it is possible to easily deflect the electron beam E emitted from the cold cathode 45 _k .

Further, by applying a voltage so that the magnitude relationship between the voltages VF _k-1 and VF _{k + 1} applied to the focus electrodes 43 _k-1 and 43 _{k + 1} is temporally switched, it is focused by the focus electrode 43 _k. The electron beam E can be oscillated.

In this way, the voltage VF _k (the voltage at which the electron beam E converges) is applied to the focus electrode 43 _k corresponding to the cold cathode 45 _k that should emit the electron beam E, and adjacent to the focus electrode 43 _k on one side. focus electrode 43 and the voltage VF _k-1 is applied to _k-1 (first voltage), the voltage VF k _{+ 1} (second to be applied to the focus electrode 43 k _{+ 1} adjacent to the focusing electrode 43 _k on the other side of By applying a voltage so that the magnitude relationship with the voltage) changes over time, the electron beam E focused by the focus electrode 43 _k is vibrated, and electrons are emitted to the phosphors 19 corresponding to the respective pixels A. By increasing the number of the cold cathodes 45, the luminance variation and flickering between the pixels A can be suppressed, and a higher quality image can be obtained.

8 and 9, the voltage is applied only to the focus electrodes 43 _k-1 and 43 _{k + 1} adjacent to both sides of the focus electrode 43 _k corresponding to the cold cathode 45 _k that should emit the electron beam E. has been described as an example, a voltage may be applied to the plurality of focus electrodes including a focus electrode _{43 k-1, 43 k +} 1 adjacent to both sides of the focus electrode 43 _k. That is, by applying a voltage VF _k-1 the focus electrode 43 _k-1 to the focus electrode of at least including one side adjacent to the focus electrode 43 _k corresponding to the cold cathode 45 _k should be released electron beam E, focus electrode 43 _k and the focus electrode 43 k _{+ 1} adjacent on the other may be applied to voltage VF k _{+ 1} to the focus electrode of the other side including at least. In short, it is sufficient to form equipotential lines D3, D4 shown in FIGS. 8 and 9, the focusing electrode 43 _k-1 adjacent to and on both sides of the focus electrode 43 _k Again, 43 k + ₁ only The same effect as when a voltage is applied can be obtained.

FIG. 10 is a diagram showing an example of a driving waveform of the field emission display according to the present embodiment. 10, (a) shows the waveform of the voltage pulse applied to the gate electrodes 25 _{1 to} 25 _k−1 , (b) shows the waveform of the voltage pulse applied to the gate electrode 25 _k , and (c) shows the gate electrode 25 _{k +. 1} shows a waveform of a voltage pulse applied to ₁ , (d) shows a waveform of a voltage pulse applied to the gate electrodes 25 _{k + 2 to} 25 _n , and (e) shows a waveform of a voltage pulse applied to the focus electrodes 43 ₁ to 43 _k−1. (F) is a waveform of a voltage pulse applied to the focus electrode 43 _k , (g) a waveform of a voltage pulse applied to the focus electrode 43 _{k + 1} , and (h) is applied to the focus electrodes 43 _{k + 2} to 43 _n . The waveform of the voltage pulse is shown respectively.

Next, a method for driving the field emission display 40 will be described with reference to FIG. 10, taking as an example the case of scanning the scanning line B _k (k is a natural number of 1 ≦ k ≦ n).

  Also in the field emission display 40 of the present embodiment, similarly to the field emission display 10 of the first embodiment, one horizontal scanning period (1H) is divided into two periods, and the first half H / 2 period. The first image data is displayed by vibrating the electron beam E, and the second image data is displayed without vibrating the electron beam E in the latter half H / 2 period.

Specifically, at time t ₁ , the voltage V _GE is applied to the gate electrode 25 _k corresponding to the scanning line B _k , and the voltage V _G0 is applied to the other gate electrodes 25 _{1 to} 25 _k−1 and 25 _{k + 1 to} 25 _n. (voltage for focusing and emitting electron beams E) focus electrode 43 _k to the voltage V _FF opposed to the gate electrode 25 _k, electrons in the focus electrode 43 ₁ ~43 _k-1 adjacent to the focus electrode 43 _k on one side voltage V _FW for deflecting the beam E, with respectively applied voltage V _F0 for deflecting the electron beam E in the focus electrode 43 k _{+ 1} ~43 _n adjacent to the focusing electrode 43 _k on the other side, the cathode A data voltage pulse corresponding to the first image data is applied to the electrodes 23 ₁ to 23 _m . The voltages V _F0 , V _FF , and V _FW are voltages that satisfy the relationship of V _F0 > V _FF > V _FW .

As a result, during the period from time t ₁ to time t ₂ , the equipotential line D4 as described above with reference to FIG. 9 is formed, and the electron beam E emitted from the cold cathode 45 _k is converged and converged. E is deflected to the cold cathode 45 _{k + 1} side (the lower side of the field emission display 40).

Next, at time t ₂ Oite, focus electrode 43 ₁ ~43 _k-1 voltage V _F0 for deflecting the electron beam E, the voltage for deflecting the electron beam E in the focus electrode 43 k _{+ 1} ~43 _n V _FW is applied respectively.

As a result, during the period from time t ₂ to time t ₃ , the equipotential line D3 as described above with reference to FIG. 8 is formed, and the electron beam E emitted from the cold cathode 45 _k is converged and converged. E is deflected to the cold cathode 45 _k-1 side (above the field emission display 40).

As described above, in the first half of the horizontal scanning period (1H), the voltage pulse whose phase is shifted by half wavelength between the focus electrodes 43 ₁ to 43 _k-1 and the focus electrodes 43 _{k + 1} to 43 _n during the H / 2 period. (Electron beam deflection voltage pulse) is applied, and a data voltage pulse corresponding to the first image data is applied to the cathode electrodes 23 ₁ to 23 _m to thereby generate an electron beam E emitted from the cold cathode 45 _k. The focused electron beam E can be vibrated and an image corresponding to the first image data can be displayed.

The number of voltage pulses applied to the focus electrodes 43 ₁ to 43 _k-1 and the focus electrodes 43 _{k + 1} to 43 _n in the first half H / 2 period may be one or more. The form is not limited.

Next, at time t ₃ , the voltage V _F0 is applied to the focus electrodes 43 _{k + 1} to 43 _n , and the data voltage pulse corresponding to the second image data is applied to the cathode electrodes 23 ₁ to 23 _m , An image corresponding to the second image data is displayed without oscillating the electron beam E during the latter half H / 2 period.

In the case where the scanning line B _{k + 1} is scanned in the subsequent horizontal scanning period from time t _{4 to} t ₆ , scanning can be performed by the same method as that for the scanning line B _k . Further, the other scanning lines B _{1 to} B _k−1 and B _{k + 2 to} B _n can be scanned by the same method as the scanning line B _k .

  According to the present embodiment, one horizontal scanning period (1H) is divided into two, and the first image data is displayed by vibrating the focused electron beam E using the first half H / 2 period. By displaying the second image data without oscillating the focused electron beam E using the latter H / 2 period, the number of cold cathodes 45 that emit electrons to the phosphors 19 corresponding to the respective pixels A can be determined. By increasing the luminance, it is possible to suppress luminance variation and flickering between the pixels A and display a higher quality image.

(Third embodiment)
FIG. 11 is a perspective view showing an outline of a field emission display according to a third embodiment of the present invention. In FIG. 11, the same components as those of the field emission display 40 of the second embodiment are denoted by the same reference numerals.

As shown in FIG. 11, the field emission display 50 includes n scanning lines B _{1 to} B _n , and includes a front plate 11, a data driver 13, a scanning driver 14, a control device 15, The data input terminal 16, the back plate 51, and the cathode drive circuit 55 are provided.

The back plate 51 includes a substrate 21, m (m is a natural number) gate electrodes 25 _{1 to} 25 _m , insulating layers 24 and 42, n (n is a natural number) focus electrodes 43 ₁ to 43 _n , It has a cathode electrode 52 and a plurality of cold cathodes 53.

The gate electrodes 25 _{1 to} 25 _m are provided on the insulating layer 24 so that the longitudinal directions thereof are the Y and Y directions. The gate electrodes 25 _{1 to} 25 _m are connected to the data driver 13 and are applied with data voltage pulses.

The focus electrodes 43 ₁ to 43 _n are _n electrodes formed in a band shape, and are arranged at a position closest to the front plate 11 among the plurality of stacked electrodes. The focus electrodes 43 ₁ to 43 _n are provided on the insulating layer 42 so that the longitudinal directions thereof are the X and X directions. The focus electrodes 43 ₁ to 43 _n are connected to the scanning driver 14 and applied with scanning voltage pulses. The focus electrodes 43 ₁ to 43 _n are electrodes orthogonal to the gate electrodes 25 _{1 to} 25 _m .

  The cathode electrode 52 is a plate-like electrode and is a common electrode for the plurality of cold cathodes 53. The cathode electrode 52 is connected to the cathode drive circuit 55.

  Thus, by making the cathode electrode 52 a single plate-like electrode, the step of patterning the cathode electrode 52 becomes unnecessary, and therefore the manufacturing process of the field emission display 50 can be simplified. Further, since only one drive circuit is required for the cathode electrode 52, the number of drive circuits is reduced as compared with the field emission display 40 of the second embodiment that requires m cathode drive circuits. can do.

A plurality of cold cathodes 53 are provided in a region K where the gate electrodes 25 _{1 to} 25 _m and the focus electrodes 43 ₁ to 43 _n are orthogonal to each other. The cold cathode 53 has the same configuration as the cold cathode 45 of the second embodiment, except that the cathode electrode 52 is provided instead of the cathode electrodes 23 ₁ to 23 _m .

  12 and 13 schematically show cross-sectional views of the field emission display when the electron beam is deflected.

As shown in FIG. 12, when the electron beam E emitted from the cold cathode 53 _k is deflected to the focus electrode 43 _k-1 side (above the field emission display 50), the electron beam is applied to the focus electrode 43 _k. E together applies a voltage VF _k focusing, voltage to the focus electrode 43 _k-1 and the adjacent focus electrode 43 _k on one side VF _k-1 (first voltage), the focusing electrode 43 _k on the other side And a voltage VF _{k + 1} (second voltage) smaller than the voltage VF _{k- 1} is applied to the adjacent focus electrode 43 _{k + 1} . As a result, an equipotential line D5 as shown in FIG. 12 is formed to focus the electron beam E emitted from the cold cathode 53 _k and deflect the focused electron beam E toward the focus electrode 43 _k-1. Can be made.

As shown in FIG. 13, when the electron beam E emitted from the cold cathode 53 _k is deflected to the focus electrode 43 _{k + 1} side (the lower side of the field emission display 50), the electron beam is applied to the focus electrode 43 _k. E together applies a voltage VF _k focusing, voltage to the focus electrode 43 _k-1 and the adjacent focus electrode 43 _k on one side VF _k-1 (first voltage), the focusing electrode 43 _k on the other side A voltage VF _{k + 1} (second voltage) larger than the voltage VF _{k- 1} is applied to the focus electrode 43 _{k + 1} adjacent to the _first electrode. As a result, an equipotential line D6 as shown in FIG. 13 is formed to focus the electron beam E emitted from the cold cathode 45 _k and deflect the focused electron beam E toward the focus electrode 43 _{k + 1.} Can be made.

Further, by applying a voltage so that the magnitude relationship between the voltages VF _k-1 and VF _{k + 1} applied to the focus electrodes 43 _k-1 and 43 _{k + 1} is temporally switched, it is focused by the focus electrode 43 _k. The electron beam E can be oscillated.

12 and 13, the voltage is applied only to the focus electrodes 43 _k−1 and 43 _{k + 1} adjacent to both sides of the focus electrode 43 _k corresponding to the cold cathode 53 _k that should emit the electron beam E. has been described as an example, a voltage may be applied to the plurality of focus electrodes including a focus electrode _{43 k-1, 43 k +} 1 adjacent to both sides of the focus electrode 43 _k. That is, by applying a voltage VF _k-1 the focus electrode 43 _k-1 to the focus electrode of at least including one side adjacent to the focus electrode 43 _k corresponding to the cold cathode 53 _k should be released electron beam E, focus electrode 43 _k and the focus electrode 43 k _{+ 1} adjacent on the other may be applied to voltage VF k _{+ 1} to the focus electrode of the other side including at least. In short, it is sufficient to form equipotential lines D5, D6 shown in FIGS. 12 and 13, the focusing electrode 43 _k-1 adjacent on both sides of the case focusing electrode 43 _k also, 43 k + ₁ only The same effect as when a voltage is applied can be obtained.

FIG. 14 is a diagram showing an example of a driving waveform of the field emission display according to the present embodiment. 14, (a) shows the waveform of the voltage pulse applied to the focus electrodes 43 ₁ to 43 _k−1 , (b) shows the waveform of the voltage pulse applied to the focus electrode 43 _k , and (c) shows the focus electrode 43. The waveform of the voltage pulse applied to _{k + 1} , (d) shows the waveform of the voltage pulse applied to the focus electrodes 43 _{k + 2} to 43 _n , respectively.

Next, a method for driving the field emission display 50 will be described with reference to FIG. 14 by taking as an example the case of scanning the scanning line B _k (k is a natural number of 1 ≦ k ≦ n).

  Also in the field emission display 50 of the present embodiment, as in the field emission display 40 of the second embodiment, one horizontal scanning period (1H) is divided into two periods, and the first half H / 2 period. The image corresponding to the first image data is displayed by oscillating the focused electron beam E, and the image corresponding to the second image data without oscillating the focused electron beam E in the second half H / 2 period. Display.

Specifically, at time t ₁ , the voltage V _FF (voltage for focusing the electron beam) is applied to the focus electrode 43 _k corresponding to the scanning line B _k , and the electron beam E is deflected to the focus electrodes 43 ₁ to 43 _k−1 . A voltage V _FW for application and a voltage V _F0 (V _FF > V _F0 > V _FW ) for deflecting the electron beam E are applied to the focus electrodes 43 _{k + 1} to 43 _n , respectively, and the gate electrodes 25 _{1 to} 25 _m A voltage pulse for data corresponding to the first image data is applied.

As a result, during the period of time t _{1 to} t ₂ , the equipotential line D6 as described in FIG. 13 is formed, and the focused electron beam E emitted from the cold cathode 53 _k is focused on the cold cathode 53 _{k +.} It is deflected to the ₁ side (the lower side of the field emission display 50).

In the present embodiment, the focus electrodes 43 ₁ to 43 _n pass electrons emitted from the cold cathode emitters 29 _{1 to} 29 _{n at} the voltage V _FF to reach the phosphor 19, and the voltage V _F0. In addition, electrons emitted from the cold cathode emitters 29 _{1 to} 29 _{n at the} voltage V _FW reach the gate electrodes 25 _{1 to} 25 _n (the phosphor 19 is not irradiated with an electron beam). Therefore, in order to deflect the electron beam E, the voltage V _FW must be less than the voltage V _F0, the magnitude relation between the voltage _{V FF, V F0, V FW} , and V _FF> V _F0> V _FW Become.

Next, at time t ₂ Oite, focus electrode 43 ₁ ~43 _k-1 voltage V _F0 for deflecting the electron beam E, the voltage for deflecting the electron beam E in the focus electrode 43 k _{+ 1} ~43 _n V _FW is applied respectively.

As a result, during the period of time t _{2 to} t ₃ , the equipotential line D5 as described with reference to FIG. 12 is formed, and the focused electron beam E emitted from the cold cathode 53 _k is focused on the cold cathode 53 _k. It is deflected to the _-1 side (the upper side of the field emission display 50).

Thus, in H / 2 period of the first half of one horizontal scanning period (1H), the voltage V _FF (voltages for focusing the electron beam) is applied to the focus electrode 43 _k, the focus electrode 43 ₁ ~ 43 _k-1 A voltage pulse (voltage pulse for electron beam deflection) whose phase is shifted by a half wavelength is applied to the focus electrodes 43 _{k + 1} to 43 _n and data corresponding to the first image data is applied to the gate electrodes 25 _{1 to} 25 _m . By applying the voltage pulse for operation, the focused electron beam E can be oscillated to display an image corresponding to the first image data.

Next, at time t ₃ , a voltage V _F0 is applied to the focus electrodes 43 _{k + 1} to 43 _n and a data voltage pulse corresponding to the second image data is applied to the gate electrodes 25 _{1 to} 25 _m . An image corresponding to the second image data is displayed without oscillating the electron beam E focused in the latter H / 2 period.

Even when the scanning line B _{k + 1} is scanned in one horizontal scanning period from time t _{4 to} time t ₆ , scanning can be performed by the same method as that for the scanning line B _k . Further, the other scanning lines B _{1 to} B _k−1 and B _{k + 2 to} B _n can be scanned by the same method as the scanning line B _k .

  According to the present embodiment, it is possible to display a high-definition image while suppressing degradation of the resolution of the display image, and to simplify the manufacturing process of the field emission display 50. Further, the cost of the field emission display 50 can be reduced by reducing the number of drive circuits.

  In FIG. 11, one plate-like cathode electrode 52 is used as an electrode common to the plurality of cold cathodes 53, but instead of using the cathode electrode 52 as an electrode common to the cold cathode 53, one plate-like gate is used. The electrode may be an electrode common to the plurality of cold cathodes 53, and the cathode electrode 52 may be divided into strips and used as data electrodes.

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to such specific embodiments, and within the scope of the present invention described in the claims, Various modifications and changes are possible. The present invention is also applicable to, for example, a monochrome display that is not color.

  INDUSTRIAL APPLICABILITY According to the present invention, the present invention can be applied to a field emission display and a driving method thereof that can reduce luminance variation and flicker between pixels and obtain a high-quality image.

It is the perspective view which showed the outline of the field emission display of the 1st Embodiment of this invention. It is sectional drawing of the cold cathode of this Embodiment. FIG. 2 is a diagram (part 1) schematically showing a cross-sectional view of a field emission display when an electron beam is deflected by a voltage applied to a gate electrode. FIG. 6 is a diagram (part 2) schematically showing a cross-sectional view of a field emission display when an electron beam is deflected by a voltage applied to a gate electrode. It is the figure which showed an example of the drive waveform of the field emission type display of this Embodiment. It is the perspective view which showed the outline of the field emission display of the 2nd Embodiment of this invention. It is sectional drawing of the cold cathode of this Embodiment. FIG. 2 is a diagram (part 1) schematically showing a cross-sectional view of a field emission display when an electron beam is deflected. FIG. 6 is a diagram (part 2) schematically showing a cross-sectional view of a field emission display when an electron beam is deflected. It is the figure which showed an example of the drive waveform of the field emission type display of this Embodiment. It is the perspective view which showed the outline of the field emission display of the 3rd Embodiment of this invention. FIG. 2 is a diagram (part 1) schematically showing a cross-sectional view of a field emission display when an electron beam is deflected. FIG. 6 is a diagram (part 2) schematically showing a cross-sectional view of a field emission display when an electron beam is deflected. It is the figure which showed an example of the drive waveform of the field emission type display of this Embodiment.

Explanation of symbols

10, 40, 50 Field emission display 11 Front plate 12, 41, 51 Rear plate 13 Data driver 14 Scanning driver 15 Control device 16 Data input terminal 17, 21 Substrate 17A Bottom surface 18 Anode electrode 19 Phosphor 19A Red phosphor 19B Green phosphor 19C Blue phosphor 21A Upper surface 23, 23 ₁ to 23 _m , 52 Cathode electrode 24, 42 Insulating layer 25, 25 _{1 to} 25 _n , 25 _k−1 , 25 _k , 25 _{k + 1} , 25 ₁ to 25 25 _m gate electrodes 27, 27 _k-1 , 27 _k , 27 _{k + 1} , 45, 45 _k-1 , 45 _k , 45 _{k + 1} , 53, 53 _{k -1} , 53 _k , 53 _{k + 1} cold cathode 28, 48 Opening 29, 29 _k-1 , 29 _k , 29 _{k + 1} Cold cathode emitter 30 Data processing means 43, 43 ₁ to 43 _n , 43 _k-1 , 43 _k , 43 _{k + 1} Focus electrode 46 Focus Electrode dry 55 cathode drive circuit a input image data A pixel B ₁ .about.B _n scan lines D1~D6 equipotential line E electron beam F, J, K region

Claims (6)

A front plate having a phosphor;
In a field emission display comprising a back plate having a cold cathode composed of a plurality of electrodes and a cold cathode emitter laminated via an insulating layer,
Of the plurality of stacked electrodes, the electrode closest to the front plate is divided into a plurality of strip electrodes, and a predetermined pulse voltage is applied to at least three strip electrodes among the plurality of strip electrodes, and the cold cathode Has the function of vibrating the electron beam emitted from
Input image data based on the luminance level of adjacent pixels, first image data in which an image is displayed by vibrating the electron beam, and second image data in which an image is displayed without vibrating the electron beam A field emission display characterized in that data processing means is provided .   The plurality of stacked electrodes are a plurality of cathode electrodes formed in a strip shape, and a plurality of gate electrodes formed in a strip shape orthogonal to the plurality of cathode electrodes and closest to the front plate. 2. The field emission display according to 1.   The plurality of stacked electrodes include a plurality of striped cathode electrodes, a plurality of striped gate electrodes orthogonal to the cathode electrode, and a strip-shaped facing the plurality of gate electrodes and closest to the front plate. 2. The field emission display according to claim 1, wherein the field emission display is a plurality of focus electrodes.   The plurality of stacked electrodes include a single cathode electrode having a plate shape, a plurality of gate electrodes having a strip shape, and a plurality of strip shapes orthogonal to the plurality of gate electrodes and closest to the front plate. 2. The field emission display according to claim 1, wherein the field emission display is a focus electrode.   The pulse voltage is at least other than the strip electrode corresponding to the cold cathode to emit the electron beam so that the electron beam oscillates in one horizontal scanning period when the horizontal scanning period of the scanning line is divided into two. The field emission display according to any one of claims 1 to 4, wherein a non-constant voltage is applied to one strip electrode. A front plate having a phosphor;
In a driving method of a field emission display comprising a back plate having a cold cathode composed of a plurality of electrodes and a cold cathode emitter laminated via an insulating layer,
Of the plurality of electrodes, the electrode closest to the front plate is divided into a plurality of strip electrodes,
Among the plurality of strip electrodes, a first voltage applied to a strip electrode on one side including at least a strip electrode corresponding to a cold cathode to emit an electron beam and a cold strip to emit the electron beam. A voltage is applied so that the magnitude relationship between the band-like electrode corresponding to the cathode and the second voltage applied to the other-side band-like electrode including at least the adjacent electrode on the other side is switched to vibrate the electron beam. Has a function to
The data processing means displays first image data in which the image is displayed by vibrating the electron beam based on the luminance level of the adjacent pixels, and the image is displayed without vibrating the electron beam. It is divided into second image data, and the electron beam is vibrated when displaying the first image data, and the electron beam is not vibrated when displaying the second image data. Driving method of field emission display.

Images