KR20060104114A - Method of compensating uniformity among pixels of electron emission panel, apparatus thereof - Google Patents

Abstract

The present invention relates to a method for compensating for the uniformity between pixels of an electron emitting panel and an apparatus thereof capable of improving the uniformity between pixels of an electron emitting panel made of an electron emitting device. The method for compensating the uniformity between pixels of an electron emission panel according to the present invention includes a method for compensating for the electron emission panel in which pixels are defined in regions where scan electrodes and data electrodes which are alternately arranged side by side intersect each other from an image signal input from the outside. Generating an input gradation displayed on the pixel and driving the electron emission panel in each pixel unit according to the input gradation to generate compensation data; And a compensation driving step. The compensation data generating step measures the output gradation output to each pixel according to the same input gradation for all the pixels, and determines the compensation value in each pixel from the output gradation difference between each pixel. In the compensation driving step, the electron emission panel is driven with respect to the input gradation in each pixel by reflecting a compensation value by the output gradation difference between the pixels in each pixel. According to the present invention, it is possible to improve the uniformity between pixels of an electron emitting panel made of an electron emitting device.

Description

Method of compensating uniformity among pixels of electron emission panel, apparatus etc.

1 is a perspective view showing an embodiment of an electron emission panel to which a method for compensating the uniformity between pixels of an electron emission panel of the present invention and a device thereof may be applied.

2 is a perspective view showing another embodiment of an electron emission panel to which the method of compensating for the uniformity between pixels of the electron emission panel and the device of the present invention can be applied.

3 is a view schematically illustrating an electrode arrangement to which a driving signal is applied in the electron emission panel illustrated in FIGS. 1 and 2.

4 is a flowchart schematically illustrating a compensation data generation step in a method for compensating for uniformity between pixels of an electron emission panel according to a preferred embodiment of the present invention.

FIG. 5 is a flow chart schematically showing a relationship between gate voltage and emission current in different pixels in a method for compensating the uniformity between pixels of an electron emission panel and an electron emission apparatus to which the device is applied, according to a preferred embodiment of the present invention.

FIG. 6 is a graph schematically illustrating a principle of determining a compensation value in the compensation value determining step in the compensation data generating step of FIG. 4.

7 is a flowchart schematically illustrating a compensation value determining step of FIG. 6.

8 is a flowchart schematically illustrating a compensation driving step in the method for compensating for uniformity between pixels of an electron emission panel according to a preferred embodiment of the present invention.

9 is a graph schematically illustrating a compensation value setting step in the compensation driving step of FIG. 8.

FIG. 10 is a timing diagram schematically illustrating a compensation driving principle by pulse width modulation as an embodiment of the driving step of FIG. 8.

FIG. 11 is a timing diagram schematically illustrating a compensation driving principle by amplitude modulation as an embodiment of the driving step of FIG. 8.

12 is a schematic block diagram of an electron emission apparatus to which the method and device for compensating the uniformity between pixels of an electron emission panel according to a preferred embodiment of the present invention.

FIG. 13 schematically illustrates an embodiment of a method for compensating for uniformity between pixels of an electron emission panel and a compensation table in the apparatus according to the present invention.

<Description of Symbols for Main Parts of Drawings>

10: electron emission panel, 60: output gradation measurement unit,

70: compensation unit, 71: compensation control unit,

72: first storage means, 73: second storage means,

74: image filter, 75: data drive control unit.

The present invention relates to a method and apparatus for driving an electron emission panel employing an electron emission device, and more particularly, to an electron emission panel that can improve uniformity between pixels of an electron emission panel made of an electron emission device. An inter pixel uniformity compensation method and apparatus thereof are provided.

In general, an electron emission device has a method using a hot cathode and a cold cathode as an electron source.

The electron-emitting device using the cold cathode is a field emitter array (FEA) type, a surface conduction emitter (SCE) type, a metal-insulator-metal (MIM) type, a metal-insulator-semiconductor (MIS) type, and a BSE. (Ballistic electron Surface Emitting) type and the like are known.

The FEA type has a low work function or ?? When the material with high function is used as the electron emission source, it uses the principle that electrons are easily released by electric field difference in vacuum, and it is a tip structure with pointed tip structure mainly made of molybdenum (Mo), silicon (Si), Graphite, DLC Carbon-based materials such as (Diamond Like Carbon), and devices that apply nano-materials such as nanotubes or nanowires to electron emission have been developed.

The SCE type is a device in which an electron emission part is formed by providing a conductive thin film between the first electrode and the second electrode disposed to face each other on a first substrate and providing microcracks to the conductive thin film. The device utilizes a principle that electrons are emitted from the electron emission portion, which is the fine gap, by applying a voltage to the electrode to flow a current to the surface of the conductive thin film.

The MIM type and the MIS type electron emitting devices each form an electron emitting portion formed of a metal-dielectric layer-metal (MIM) and a metal-dielectric layer-semiconductor (MIS) structure, and are disposed between two metals or metals and semiconductors having a dielectric layer therebetween. It is a device using the principle that electrons are released as they move and accelerate from a metal having a high electron potential or a metal having a low electron potential when a voltage is applied therebetween.

The BSE type is an average free information of electrons in a semiconductor. When the size of the semiconductor is reduced to a small dimension region, the electron supply layer is formed of a metal or a semiconductor on an ohmic electrode by using the principle that electrons travel without scattering. The insulating layer and the metal thin film are formed thereon to emit electrons by applying power to the ohmic electrode and the metal thin film.

The electron emitting panel made of the electron emitting device includes scan electrodes extending in one direction and data electrodes extending to intersect the scan electrodes, and a pixel may be defined in the crossing regions. Each pixel emits visible light, and its luminance varies depending on a driving signal applied to each pixel.

On the other hand, in the case where the same driving signal is applied to each pixel of the electron emission panel, visible light having the same luminance should be emitted from each pixel. However, due to various manufacturing process problems including the characteristics of the electron emission source of the electron emitting panel and the characteristics of the fluorescent film, even if the same driving signal is applied to each pixel, the same brightness is not expressed on the panel. Unevenness may arise.

The present invention is to solve the various problems including the above problems, and to determine the compensation value that can compensate for the characteristics of the emission current or luminance characteristics of each pixel for each gray scale, the electron emitting panel It is an object of the present invention to provide a method for compensating the uniformity between pixels of an electron emitting panel and a device for improving the uniformity between pixels of an electron emitting panel made of electron emitting devices by reflecting the compensation value during driving. It is done.

In order to achieve the above object and various other objects, the method for compensating the uniformity between pixels of the electron emission panel according to the present invention includes electrons in which pixels are defined in regions where scan electrodes and data electrodes that are alternately arranged side by side cross each other. Generating an input gradation displayed on each pixel from an image signal input from the outside, and driving the electron emission panel in each pixel unit according to the input gradation to generate a compensation data; And a compensation driving step.

The compensation data generating step measures the output gradation output to each pixel according to the same input gradation for all the pixels, and determines the compensation value in each pixel from the output gradation difference between each pixel. In the compensation driving step, the electron emission panel is driven with respect to the input gradation in each pixel by reflecting a compensation value by the output gradation difference between the pixels in each pixel.

In the compensation data generating step, a measurement input gray scale determination step of determining a specific input gray scale to be displayed on all the pixels, a test driving step of test driving all the pixels with the measured input gray scale, and each of the pixels An output gradation measurement step of measuring the output gradation by the measurement input gradation in the step of determining a compensation value at each pixel from the difference of the output gradations between each pixel, and each of the And a compensation table generating step of generating a compensation table from a compensation value at the pixel of.

In the compensation driving step, a display gradation determining step of determining an input gradation to be displayed on each pixel from the image signal as a display gradation, and reflecting the compensation value of each pixel of the compensation table with respect to the display gradation. Compensation display gradation determining step for determining the compensation display gradation to drive the driving, driving step for driving the electron emitting panel according to the compensation display gradation.

The pixel-to-pixel uniformity compensator of an electron emission panel according to another aspect of the present invention includes an image signal input from an external device with respect to an electron emission panel in which pixels are defined in regions where scan electrodes and data electrodes that are alternately arranged side by side intersect. An output gradation generated from each pixel by driving the electron emission panel in each pixel unit according to the input gradation, and measuring an output gradation output to each pixel by the input gradation A gray scale measuring unit; And calculating a compensation value at each pixel for each input gradation from the input gradation and an output gradation corresponding thereto, and reflecting the compensation value at each pixel for the input gradation at each pixel. Compensation unit for driving the discharge panel is provided.

According to the present invention, a compensation value capable of compensating the characteristics of the emission current or the luminance characteristic of each pixel with respect to each of the gray levels can be determined, and the compensation value can be driven when the electron emission panel is driven. In this way, the uniformity between pixels of the electron emitting panel made of the electron emitting device can be improved.

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the present invention.

1 is a perspective view showing an embodiment of an electron emission panel to which a method for compensating the uniformity between pixels of an electron emission panel of the present invention and a device thereof may be applied.

Referring to FIG. 1, the electron emission panel 10 may include a space bar supporting the first panel 2, the second panel 3, and the first panel 2 and the second panel 3 spaced apart from each other. (space bars) 41,... 43.

The first panel 2 includes a transparent first substrate 21, an anode electrode 22, and fluorescent cells F _R11 ,..., F _Bnm .

The anode electrode 22 is disposed on the first substrate 21 in the direction from the first substrate 21 to the second substrate 31, and the fluorescent cells on the anode electrode 22 in the direction of the second substrate 31. (F _R11 , ..., F _Bnm ) are disposed. Red, blue and green phosphors are disposed in the fluorescent cells, respectively.

The second panel 3 includes the second substrate 31, the electron emission sources E _R11 ,..., E _Bnm , the insulating layer 33, and the cathode electrodes C _R1 ... ., C _Bm ) and gate electrodes G ₁ , ..., G _n .

The cathode electrodes C _R1 , ..., C _Bm are electrically connected to the electron emission sources E _R11 , ..., E _Bnm , and the insulating layer 33 and the gate electrodes G _{1 ,.} .., G _n ) is formed with through holes H _R11 , ..., H _Bnm corresponding to electron emission sources E _R11 , ..., E _Bnm .

Electron emission sources whose potential difference is electrically connected to the cathode electrodes due to the driving voltages applied to the cathode electrodes and the gate electrodes (generally, the voltage applied to the cathode electrodes is lower than the voltage applied to the gate electrodes). When the electron emission exceeds the electron emission start voltage at which electron emission can be initiated, electrons start to be emitted from the electron emission sources. At this time, when a high positive voltage of 1 to 4 kilovolts (KV) is applied to the anode, electrons emitted from the electron emission sources are accelerated to converge into fluorescent cells and collide with fluorescent materials of the fluorescent cells to generate visible light. .

2 is a perspective view showing another embodiment of an electron emission panel to which the method of compensating for the uniformity between pixels of the electron emission panel and the device of the present invention can be applied.

Referring to the drawings, the electron emission panel illustrated in FIG. 2 has the same configuration and operation principle except that the electron emission panel, cathode electrodes, and gate electrodes illustrated in FIG. 1 are different from each other.

The electron emission panel 10 may include space bars supporting the first panel 2, the second panel 3, and the first panel 2 and the second panel 3 spaced apart from each other. 41, ..., 43).

The first panel 2 includes a transparent first substrate 21, an anode electrode 22, and fluorescent cells F _R11 ,..., F _Bnm .

The anode electrode 22 is disposed on the first substrate 21 in the direction from the first substrate 21 to the second substrate 31, and the fluorescent cells on the anode electrode 22 in the direction of the second substrate 31. (F _R11 , ..., F _Bnm ) are disposed. Red, blue and green phosphors are disposed in the fluorescent cells, respectively.

The second panel 3 includes the second substrate 31, the electron emission sources E _R11 ,..., E _Bnm , the insulating layer 33, and the cathode electrodes C _R1 ... ., C _Bm ) and gate electrodes G ₁ ,..., G _n .

The cathode electrodes C _R1 , ..., C _Bm are electrically connected to the electron emission sources E _R11 , ..., E _Bnm , and the insulating layer 33 and the gate electrodes G _{1 ,.} .., G _n ) is formed with through holes H _R11 , ..., H _Bnm corresponding to electron emission sources E _R11 , ..., E _Bnm .

The cathode electrodes C are electrically connected to the electron emission sources E, extend through the insulating layer 33 on the gate electrodes G in the direction of the first substrate, and extend to the sides of the electron emission sources E. Opposite electrodes T are formed.

In the electron emission panel having the structure in which the gate electrodes G are positioned below the cathode electrodes C as shown in FIG. 2, the cathode is caused by a potential difference between the counter electrode T and the cathode electrode C connected to the gate electrode. The electrons emitted from the electrode are slightly attracted toward the counter electrode T and then accelerated toward the anode electrode 22 of the first panel 2.

3 is a view schematically illustrating an electrode arrangement to which a driving signal is applied in the electron emission panel illustrated in FIGS. 1 and 2.

Referring to the drawings, scan electrodes extend in one direction and data electrodes extend in a direction crossing the direction in which the scan electrodes extend. One pixel (pixel, Px), which is a basic unit in which an image is expressed in the crossing area, is defined. The scan driving signal is sequentially applied to the scan electrodes, and the data driving signal is applied to the data electrodes in accordance with the scan signal to emit visible light having a luminance corresponding to each pixel.

In FIG. 3, one region where the scan electrode and the data electrode cross each other is defined as one pixel, but fluorescent materials for emitting red, green, and blue light may be applied according to the direction in which the data electrodes extend. Since visible light is emitted in an area where the data electrodes and one scan electrode intersect, one pixel may be defined in an area where the three data electrodes and one scan electrode intersect. In this case, an area where one data electrode and one scan electrode intersect becomes one sub pixel.

As the scan electrodes shown in FIG. 3, they may be the cathode electrodes shown in FIGS. 1 and 2, or the gate electrodes shown in FIGS. 1 and 2. Also, as the data electrodes illustrated in FIG. 3, the gate electrodes illustrated in FIGS. 1 and 2 may be used, or the cathode electrodes illustrated in FIGS. 1 and 2 may be used.

The method for compensating the uniformity between pixels of an electron emission panel according to the present invention includes a method for compensating for the electron emission panel in which pixels are defined in regions where scan electrodes and data electrodes which are alternately arranged side by side intersect each other from an image signal input from the outside. Generating an input gradation displayed on the pixel and driving the electron emission panel in each pixel unit according to the input gradation to generate compensation data; And a compensation driving step.

The compensation data generating step measures the output gradation output to each pixel according to the same input gradation for all the pixels, and determines the compensation value in each pixel from the output gradation difference between each pixel. In the compensation driving step, the electron emission panel is driven with respect to the input gradation in each pixel by reflecting a compensation value by the output gradation difference between the pixels in each pixel.

In the following description of the present invention, the compensation data generating step is shown in FIG. 4, and the compensation driving step is shown in FIG. 8.

4 is a flowchart schematically illustrating a compensation data generation step in a method for compensating for uniformity between pixels of an electron emission panel according to a preferred embodiment of the present invention. FIG. 5 is a flow chart schematically showing a relationship between gate voltage and emission current in different pixels in a method for compensating the uniformity between pixels of an electron emission panel and an electron emission apparatus to which the device is applied, according to a preferred embodiment of the present invention.

Referring to the drawing, the step of generating the compensation data (step 400), the step of determining the measurement input gradation (steps 401, 402, 405), the test driving step (step 403), the output gradation measurement step (step 404), the compensation value determination A step (406), and a compensation table generation step (step 407).

In the measurement input gradation determining step (steps 401, 402, 405), a specific input gradation to be displayed on all pixels is determined as the measurement input gradation. In the test driving step (step 403), all the pixels are test-driven with the measurement input gradation. In the output gradation measurement step (step 404), the output gradation by the measurement input gradation in each pixel is measured. In the step of determining the compensation value (step 406), the compensation value in each pixel is determined from the difference in output gradations between each pixel. In the compensation table generating step (step 407), a compensation table is generated from the compensation values in each pixel.

In the generating of the compensation data (step 400), a compensation value of each of the pixels is obtained for each input gradation while sequentially increasing the gradation from an input gradation having a minimum gradation weight to an input gradation having a maximum gradation weight.

To this end, the measurement input gradation determining step (steps 401, 402, 405), the input gradation initialization step (step 401), determining whether the input gradation is the highest gradation weight gradation (step 402), and measuring the input gradation And changing to the next input gradation (step 405), measuring a specific input gradation to be displayed on all pixels while sequentially increasing the gradation from an input gradation with a minimum gradation weight to an input gradation with a maximum gradation weight. Determined by gradation.

That is, in the case of the embodiment expressing the image in 256 gray scales, the test operation is performed on all the pixels for each gray scale up to 255 gray scales, starting from 0 gray scales and increasing by 1 gray scale. The output gradation of can be measured.

In this case, the present invention is not limited thereto, and according to the embodiment, after initializing the input gradation (step 401) by various methods for all the input gradations, it is determined whether the test drive and the output gradation measurement have been completed for all the input gradations. In step 402, the measurement input gradation is changed (step 405), and test driving and output gradation measurement are performed on all input gradations.

In addition, according to the embodiment, instead of performing test driving and output gray scale measurement for all input gray scales, test driving and output gray scale measurement are selectively performed only on some gray scales among all gray scales, and corresponding compensation is performed. You can also get the values.

In the test driving step (step 403), a test drive is performed on all the pixels with the measurement input gradation. The test driving is performed on all the pixels with respect to the measurement input gradation determined in the measurement input gradation determining steps (steps 401, 402, and 405). . At this time, the test drive can drive the electron emission panel by the driving method shown in Fig. 10 or 11, the pulse width modulation (PWM, Pulse Amplitude) and amplitude modulation (PAM, Pulse Amplitude) according to each gray scale weight It can be driven by various methods including modulation.

In the output gradation measurement step (step 404), the output gradation by the measurement input gradation in each pixel is measured, and the output gradation may be measured by the emission current from the electron emission source or the luminance measured on the electron emission panel. will be.

That is, as an embodiment in which the output gradation is measured in the output gradation measurement step (step 404), it is electrically connected to a scan electrode or a data electrode to emit electrons, and is output from an electron emission source corresponding to each pixel. The output gradation can be measured by measuring the emission current. Also, as another embodiment in which the output gradation is measured in the output gradation measurement step (step 404), the output gradation may be measured by measuring the luminance output from each pixel.

In Figure 5, there is a discharge current from the electron emission sources corresponding in different pixels (C _1, C ₂₎ by a gate voltage to be applied according to the respective gray-scale weights are shown, each of the different pixels (C ₁ It can be seen that the emission current characteristics corresponding to C ₂ ) are represented by different curves in the C ₁ pixel and the C ₂ pixel.

That is, by the gate voltage (Vg) corresponding to the same input gradation in the C ₁ pixel emission current of (a) level is output, the C ₂ pixels (b) is the emission current, the output of the level, the compensation according to the invention If this is not done, it can be seen that the luminance expressed between the pixels of the electron emission panel is displayed differently, so that the overall image quality of the panel may be degraded.

FIG. 6 is a graph schematically illustrating a principle of determining a compensation value in the compensation value determining step in the compensation data generating step of FIG. 4. 7 is a flowchart schematically illustrating a compensation value determining step of FIG. 6. FIG. 13 schematically illustrates an embodiment of a method for compensating for uniformity between pixels of an electron emission panel and a compensation table in the apparatus according to the present invention.

Referring to the figure, the step of determining the compensation value (step 406) is to determine the compensation value in each pixel from the difference in the output grayscales between the respective pixels. A maximum output gradation pixel determination step (step 702), a compensation reference gradation determination step (step 703), and a pixel-specific compensation value determination step (step 704).

In the determination of the minimum output gradation pixel (step 701), a pixel having the minimum output gradation among all the pixels is determined. In the determination of the maximum output gradation pixel (step 702), a pixel having the maximum output gradation among all the pixels is determined. do.

In the step of determining the compensation reference gradation (step 703), an input gradation such as an output gradation of the pixel having the maximum output gradation is equal to the output gradation of the pixel having the minimum output gradation is determined as the compensation reference gradation of the measurement input gradation. In the pixel-specific compensation value determining step (step 704), a compensation value for each measurement input gray level in each pixel is determined from the compensation reference gray level for each measurement input gray level.

At this time, steps 701 to 704 are preferably performed for each input gradation in the same manner as by the measurement input gradation determination steps (steps 401, 402, 405).

The method for determining a compensation value for one input gray level in the compensation value determining step (step 406) may be performed through the method shown in FIG. 6. In this embodiment, the output value is determined for each input gray level. This is an embodiment in the case where luminance is measured as gray scale.

In this case, the compensation value for each measurement input gradation in each pixel is obtained by subtracting the compensation reference gradation from an input gradation having the same output gradation as the output gradation of the pixel having the minimum output gradation for each measurement input gradation in each pixel. It is preferable to determine from the subtracted value.

For example, the first tone in the case of a (G _C) of the input gray level, a is 1 pixel (C _A) The luminance B _C, the luminance in the second pixel (C _B) is B _B, the third In the pixel C _C , the luminance is B _A. In this case, the first gradation G _C is represented by the minimum luminance B _A in the third pixel C _C and the highest luminance B _C in the first pixel C _A.

Therefore, the compensation reference gradation G0 becomes the third gradation G _A , and the compensation value of the first pixel C _A is G _A -G _A , and the compensation value of the second pixel C _B is G _B- The compensation value of G _A , the third pixel C _C is G _C -G _A. That is, if G _A gray is 250 gray, G _B gray is 252 gray, and G _C gray is 250 gray, the compensation value of the first pixel C _A is 0 and the compensation value of the second pixel C _B is 2 , The compensation value of the third pixel (C _C ) is five.

The compensation table is preferably formed by a coordinate value of each pixel and a compensation value corresponding to the coordinate value for each input gradation. In FIG. 13, a compensation in each of all pixels for one input gradation is shown. One embodiment of a compensation table is shown that corresponds to a value. The compensation table according to the present invention may be formed for each input gradation section in which the compensation table is divided into each input gradation or a plurality of sections.

That is, as an embodiment of the compensation table, the total input gradation is divided into a plurality of gradation intervals, the compensation value of each pixel is obtained for each gradation interval, and then the coordinates of each pixel for each gradation interval are obtained. It may be formed by a value and a compensation value corresponding to the coordinate value. At this time, the compensation value in each gradation section is preferably determined as the compensation value of the highest input gradation in each gradation section.

At this time, in the compensation value setting step (step 803) shown in Figure 8, the compensation value for each input grayscale may be set to a value obtained by interpolation from the compensation value for each grayscale interval.

Also, as another embodiment of the compensation table, a compensation value in each grayscale section may be determined as a compensation value of an intermediate input grayscale in each grayscale section.

Further, as another embodiment of the compensation table, the compensation value in each gradation section may be determined by the arithmetic mean of the compensation values for all input gradations in each gradation section.

The compensation value determining step according to the present invention is not limited to the method according to the present embodiment, and various methods may be applied to various methods for implementing the present invention.

8 is a flowchart schematically illustrating a compensation driving step in the method for compensating for uniformity between pixels of an electron emission panel according to a preferred embodiment of the present invention. 9 is a graph schematically illustrating a compensation value setting step in the compensation driving step of FIG. 8.

Referring to the drawing, in the compensation driving step (step 800), the electron emission panel reflects the compensation value by the difference between the output gradations in each pixel with respect to the input gradation in each pixel in the compensation driving step. A display gray scale determination step (step 801), a compensation display gray scale determination step (steps 802 to 804), and a driving step (step 805) are provided.

In the display gradation determining step (step 801), an input gradation to be displayed on each pixel is determined as the display gradation from the input image signal. In the compensation display gradation determining step (steps 802 to 804), a compensation display gradation for driving each pixel is determined by reflecting the compensation value of each pixel of the compensation table with respect to the display gradation. In the driving step (step 805), the electron emission panel is driven in accordance with the compensation display gradation to display luminance of each pixel on the electron emission panel.

The compensation display gradation determining step (steps 802 to 804) is to determine a compensation display gradation for driving each pixel with respect to the display gradation, and the display gradation changing step (step 802), the compensation value setting step (step 803), and Compensation display gradation determination step (step 804) is provided.

In the display gradation changing step (step 802), the display gradation is changed to the compensation reference gradation according to the compensation reference gradation with the display gradation as an input gradation, and in the compensation value setting step (step 803), compensation for the display gradation from the compensation table is performed. A value is set, and in the step of determining the compensation display gradation (step 804), the compensation display gradation is determined from the compensation reference gradation and the compensation value for the display gradation.

The compensation value setting step (step 803) is a step of setting a compensation value for the display gray scale, an embodiment of which is shown in FIG. That is, in the case of the embodiment shown in Figure 9 is a graph showing a compensation value setting method when the compensation table is formed by dividing the entire input gradation into a plurality of gradation intervals.

That is, a compensation table is formed by obtaining a compensation value in each pixel for each of the gradation intervals, and then, for each gradation interval, by a coordinate value of each pixel and a compensation value corresponding to the coordinate value. It can be applied to the embodiment. In particular, there is an advantage in that memory can be saved as a storage means for storing the compensation table when the compensation value is determined for each section as described above.

In this case, as described above, a compensation table is formed for each section, and a value in which the compensation value in each section may be applied to the table, but according to an embodiment, the compensation value for each input gradation may be determined. It may be set to a value obtained by real-time calculation by interpolation from the compensation value for each gradation section. In this case, memory space savings and more detailed gradation compensation are possible.

In the step of determining the compensation display gradation (step 804), the compensation display gradation is determined from the compensation reference gradation and the compensation value for the display gradation, and the compensation display gradation is determined by the sum of the compensation reference gradation and the compensation value for the display gradation. desirable.

In the present embodiment, since the input gray level at the pixel whose compensation value is the maximum output gray is the same as the output gray level of the pixel having the smallest output gray, the compensation gray level is determined as a positive reference gray level. Value is obtained, and the compensation display gradation is determined by the sum of the compensation reference gradation and the compensation value for the display gradation. However, the present invention is not limited thereto, and in other embodiments, such as setting a compensation reference gradation, the compensation indication gradation may be obtained by another method.

In the driving step (step 805), the electron emission panel is driven in accordance with the compensation display gradation to display brightness of each pixel on the electron emission panel, and the pulse width modulation (PWM, Pulse) according to each gradation weight is performed. It can be driven by a variety of methods including Width Modulation (PAM) and Pulse Amplitude Modulation (PAM), the specific driving method is shown in Figures 10 and 11.

FIG. 10 is a timing diagram schematically illustrating a compensation driving principle by pulse width modulation as an embodiment of the driving step of FIG. 8. FIG. 11 is a timing diagram schematically illustrating a compensation driving principle by amplitude modulation as an embodiment of the driving step of FIG. 8.

Referring to the drawings, a gray scale expression method for adjusting the luminance of visible light emitted from the electron emission panel includes a pulse width modulation (PWM) method for controlling an application time of a data driving signal, and data. There is a pulse amplitude modulation (PAM) method for controlling the voltage magnitude of the driving signal. FIG. 10 illustrates a gray scale representation by the PWM scheme, and FIG. 11 illustrates a gray scale representation by the PAM scheme. have.

In FIG. 10, scan driving signals sequentially applied to the scan electrodes are represented as one scan driving signal for convenience.

When the scan driving signal Scan having a constant pulse width is sequentially applied to the scan electrodes, the data driving signal Data having a pulse width that varies according to the gray scale to be expressed for each luminance is applied to the data electrodes.

That is, the data driving signal may have a first data voltage V having a potential higher than the emission start voltage V _th , which is a threshold point at which electron emission can be initiated in relation to the scan driving signal, so that gray scale expression is possible according to the pulse width. _D1 ) and a second data voltage V _D2 having a potential lower than the emission start voltage V _th . The scan driving signal has a scan voltage Vscan and a predetermined pulse width PWscan during a scan period in which scan electrodes are sequentially scanned.

As illustrated in FIG. 10, when the gray level of the nth data driving signal Data [n] and the n + 1th data driving signal Data [n + 1] is the same, the nth and n + 1th data driving signals are equal to each other. Pulse widths are the same (PW [n] = PW [n + 1]). When the gradation of the n + 2 th data driving signal Data [n + 2] is lower than the gradation of the n + 1 th data driving signal Data [n + 1], the n + 2 th data driving signal Data [ n + 2]) is smaller than the pulse width of the n th data drive signal Data [n] (PW [n]> PW [n + 2]), and the n + 3 th data drive signal Data [ n + 3]) is higher than the nth data driving signal Data [n], the pulse width of the n + 3th data driving signal Data [n + 3] is the nth data driving signal ( Greater than the pulse width of Data [n] (PW [n] <PW [n + 3]). Meanwhile, the blanking signals BK [n], ... BK [n + 1] are applied to the scan electrodes and the data electrodes between the application periods of the first to fourth data driving signals.

10 illustrates that the potential of the scan driving signal is higher than that of the data driving signal. According to the electron emission panel 10 shown in FIGS. 1 and 2, potentials applied to the electron emission sources E _R11 ,..., E _Bnm electrically connected to the cathode electrodes are applied to the gate electrodes G _1. Since electrons are emitted from the electron emission sources E _R11 , ..., E _{Bnm only} at a potential lower than the potential applied to G _n ), according to the driving signal of FIG. 10, the cathodes of FIGS. The electrodes C _R1 , ..., C _Bm may be used as the data electrodes D ₁ ,..., D _m , and the gate electrodes G ₁ ,... G _n ) may be used as the scan electrodes S ₁ ,..., S _n .

In addition, the potential of the scan driving signal and the potential of the data driving signal illustrated in FIG. 10 may be applied in reverse, and in this case, the cathode electrodes C _R1 ,..., C _Bm are the scan electrodes S _1. , ..., S _n ), and the gate electrodes G ₁ ,..., G _n may be used as the data electrodes D ₁ , ..., D _m .

At this time, the driving pulse width PW [n] in the data driving signal having the respective pulse widths is the pulse width PW0 [n] corresponding to the compensation reference gradation corresponding to each input gradation and the respective compensation values PWC. [n]).

In the embodiment of the gradation representation method using the PAM method shown in FIG. 11, the embodiment is implemented by the PWM gradation representation method shown in FIG. 10 except that the amplitude of each pulse in the data driving signal is changed instead of the pulse width. It is the same as the example, so refer to it. However, the driving amplitude PA [n] in the data driving signal having the respective amplitude is the amplitude PA0 [n] according to the compensation reference gradation corresponding to each input gradation and the respective compensation value PAC [n]. ) Is the sum of

12 is a schematic block diagram of a method for compensating for uniformity between pixels of an electron emission panel and an electron emission apparatus to which the apparatus can be applied, according to the present invention.

The electron emitting device includes an electron emitting panel 10 and its driving devices 81 to 83, 60, and 70. The driving device of the electron emission panel includes an image processor 81, a compensator 70, a scan driver 83, and a data driver 82.

The image processor 81 converts an external analog image signal into a digital signal to generate internal image signals such as red (R), green (G), and blue (B) image data, clock signals, and vertical and horizontal synchronization signals. Let's do it.

Compensation section 70 generates a data driving signal (S _D) and the scan driving signal (S _S) to the drive control signal consisting of a (S _D, S _S) according to the internal image signals from the image processor 81. The data driver 82 generates a display data signal by processing the data driving signal S _D among the driving control signals S _D and S _S from the compensator 70, and generates the display data signal. It is applied to the data electrode lines of the emission panel 10. The data electrode lines may be connected to the cathode electrode lines C _R1 ,..., C _Bm or the gate electrode lines G ₁ ,..., G _n in the panel 10. The scan driver 83 processes the scan driving control signal S _S from the driving control signals _SD and S _S from the compensator 70 and applies the scan driving control signal S _S to the scan electrode lines. As the scan electrode lines, the gate electrode lines G ₁ ,..., G _n or the cathode electrode lines C _R1 ,..., C _Bm in the panel 10 may be used.

The pixel-to-pixel uniformity compensator of an electron emission panel according to an embodiment of the present invention provides an electron emission panel in which pixels are defined in regions where scan electrodes and data electrodes which are alternately arranged side by side intersect each other from an image signal input from the outside. By generating the input gradation displayed on the pixel, and driving the electron emission panel in each pixel unit according to the input gradation, the pixel to be driven by the uniformity compensation method between the pixels of the electron emission panel shown in Figs. A uniformity compensating device, comprising: an output gray scale measuring unit 60; And a compensator 70.

The output gradation measuring unit 60 measures the output gradation output to each pixel by the input gradation. The compensator 70 obtains a compensation value in each pixel for each input gradation from an input gradation and an output gradation corresponding thereto, and reflects the compensation value in each pixel for the input gradation in each pixel. To drive the electron emission panel.

The output gray scale measuring unit 60 may measure the output gray scale by measuring an emission current output from an electron emission source electrically connected to the scan electrode or data electrode to emit electrons. As another embodiment of the output gray scale measuring unit 60, the output gray scale may be measured by measuring luminance output from each pixel.

The compensation unit 70 may include a compensation control unit 71, a first storage unit 72, a second storage unit 73, an image filter 74, and a data driving control unit 75.

The compensation controller 71 obtains a compensation value in all pixels for each input gradation while sequentially increasing the input gradation from an input gradation having a minimum gradation weight to an input gradation having a maximum gradation weight. In addition, the specific input gradation to be displayed on all pixels is measured input gradation, and from the output gradation according to the measurement input gradation, the output gradation of the pixel having the maximum output gradation is the output gradation of the pixel having the minimum output gradation; Preferably, the same input gradation is determined as the compensation reference gradation of the measured input gradation.

The compensation reference gradation is obtained from an input gradation having an output gradation equal to the output gradation of a pixel having a minimum output gradation with respect to the measurement input gradation in each pixel. It is preferable to determine from the subtracted value. In this case, the compensation table may be formed by a coordinate value of each pixel and a compensation value corresponding to the coordinate value for each input gradation.

The compensation table is stored in the first storage means 72, and preferably, the compensation table includes a nonvolatile ROM (Read Only Memory). According to the present invention, when a compensation value is stored for each gradation section of the compensation table, a space of a memory in which the compensation table is stored can be saved. In this case, the applied compensation table may be the same as the compensation table in the method for compensating the uniformity between pixels of the electron emission panel illustrated in FIGS. 4 to 11.

The second storage means 73 is temporarily stored in the compensation table, it is preferably made of a random access memory (RAM) that can be accessed faster than the first storage means.

That is, when driving, the compensation table stored in the first storage means 72 is read and temporarily stored in the second storage means 73 capable of fast reading and writing. Therefore, the present invention can effectively cope with high-speed frequency characteristics of a video signal, especially when used in a high resolution video display device such as an HDTV.

In the image filter 74, when an input gradation corresponding to each pixel is to be displayed, the input gradation to be displayed on each pixel is changed to a compensation reference gradation corresponding to each input gradation. 11 to 11, the input gradation to be displayed on each pixel in the inter-pixel uniformity compensation method of the electron emission panel shown in FIG. 11 is changed to the compensation reference gradation corresponding to each input gradation.

In the data driving controller 75, the pulse width modulation (PWM) and the amplitude modulation (PAM) according to the respective gray scale weights are used to drive the electron emission panel by the driving method shown in FIG. 10 or 11. Pulse width modulation or amplitude modulation can be performed to be driven by various methods, including Pulse Amplitude Modulation. However, according to the exemplary embodiment, the data driving controller 75 may be included in the compensation controller 71.

According to the method for compensating the uniformity between pixels of an electron emitting panel according to the present invention and the apparatus thereof, a compensation value capable of compensating the characteristics of the emission current or the luminance characteristic of each pixel for each gray scale is determined, and the electron emission is determined. By driving the panel while reflecting the compensation value, the pixel-to-pixel uniformity of the electron-emitting panel made of the electron-emitting device can be improved.

That is, since the compensation value corresponding to each input gray scale is applied, the uniformity between pixels can be improved in all gray scales, and more accurate gray scale expression can be achieved.

In addition, since a reference table with a small capacity can be compensated for the entire gray scale, the product price of the electron-emitting device can be reduced.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (38)

For an electron emission panel in which pixels are defined in regions where scan electrodes and data electrodes that are alternately arranged side by side are generated, an input gradation displayed on each pixel is generated from an image signal input from the outside, and according to the input gradation By driving the electron emission panel in each pixel unit, A compensation data generation step of measuring an output gradation output to each pixel according to the same input gradation for all pixels, and determining a compensation value in each pixel from the output gradation difference between each pixel; And Between the pixels of the electron emission panel having a compensation driving step for driving the electron emission panel by reflecting the compensation value of the output gray level difference between the pixels in the respective pixels with respect to the input gray level in each pixel. Uniformity Compensation Method. The method of claim 1, The compensation data generating step, A measurement input gradation determining step of determining a specific input gradation to be displayed on all the pixels as a measurement input gradation, A test driving step of test driving all the pixels with the measurement input gradation; An output gradation measuring step of measuring the output gradation by the measurement input gradation in each pixel; A compensation value determining step of determining a compensation value in each pixel from the difference of the output gradations between each pixel, and And a compensation table generating step of generating a compensation table from the compensation values of the respective pixels. The method of claim 2, In the generating of the compensation data, an electron emission panel for obtaining a compensation value of each pixel for each input gradation while sequentially increasing the input gradation from an input gradation having a minimum gradation weight to an input gradation having a maximum gradation weight. Uniformity compensation method between pixels. The method of claim 2, In the output gray scale measurement step, measuring the output gradation by measuring the emission current output from the electron emission source that is electrically connected to the scan electrode or data electrode to measure the output gradation uniformity between the pixels. The method of claim 2, In the output gradation measuring step, the uniformity compensation method between the pixels of the electron emitting panel for measuring the output gradation by measuring the luminance output from each pixel. The method of claim 2, The compensation value determining step, Determining a pixel having the minimum output gray level among all the pixels; Determining a pixel having the maximum output gray level among all the pixels; Determining an input gradation at the pixel of which the output gradation is maximum equal to the output gradation of a pixel having the minimum output gradation as a compensation reference gradation of the measurement input gradation, and And determining a compensation value for each measurement input gradation in each pixel from the compensation reference gradation for each measurement input gradation. The method of claim 6, The compensation value for each measurement input gradation in each pixel is A method for compensating the uniformity between pixels of an electron emission panel, which is determined from a value obtained by subtracting the compensation reference gradation from an input gradation having an output gradation equal to the output gradation of a pixel having a minimum output gradation in each pixel. The method of claim 2, And the compensation table comprises, for each input gradation, a coordinate value of each pixel and a compensation value corresponding to the coordinate value. The method of claim 2, The compensation driving step, A display gradation determining step of determining an input gradation to be displayed on each pixel from the video signal as a display gradation; A compensation display gradation determining step of determining a compensation display gradation for driving each pixel by reflecting a compensation value in each pixel of the compensation table with respect to the display gradation; And a driving step of driving the electron emission panel according to the compensation display gradation. The method of claim 9, Wherein the step of determining the compensation display gradation, A display gradation changing step of changing the display gradation to the compensation reference gradation according to a compensation reference gradation using the display gradation as an input gradation; A compensation value setting step of setting a compensation value for the display gray scale from the compensation table; And a compensation display gradation determining step for determining a compensation display gradation from the compensation reference gradation and the compensation value with respect to the display gradation. The method of claim 10, The compensation table divides the entire input gradation into a plurality of gradation intervals, obtains a compensation value in each pixel for each gradation interval, and then, for each gradation interval, The uniformity compensation method between the pixels of the electron emission panel formed by the compensation value corresponding to the coordinate value. The method of claim 11, And a compensation value in each of the gradation sections is determined as a compensation value of the highest input gradation within each gradation section. The method of claim 12, And in the compensation value setting step, a compensation value for each input gradation is set to a value obtained by interpolation from the compensation value for each gradation section. The method of claim 11, And a compensation value in each of the gray scale sections is determined as a compensation value of an intermediate input gray scale in each of the gray scale sections. The method of claim 11, And a compensation value in each of the gradation sections is determined by an arithmetic mean of the compensation values for all the input gradations in each gradation section. The method of claim 10, In the step of determining the compensation display gradation, And the compensation display gradation is determined by the sum of the compensation reference gradation and the compensation value for the display gradation. The method of claim 9, In the driving step, A method for compensating for uniformity between pixels of an electron emission panel, wherein the electron emission panel is driven by pulse width modulation according to the compensation display gradation. The method of claim 9, In the pre-drive stage, A method for compensating for uniformity between pixels of an electron emitting panel, wherein the electron emitting panel is driven by amplitude modulation of a pulse according to the compensation display gray scale. For an electron emission panel in which pixels are defined in regions where scan electrodes and data electrodes that are alternately arranged side by side are generated, an input gradation displayed on each pixel is generated from an image signal input from the outside, and according to the input gradation By driving the electron emission panel in each pixel unit, An output gradation measuring unit configured to measure an output gradation output to each of the pixels by the input gradation; And Obtaining a compensation value at each pixel for each input gradation from the input gradation and an output gradation corresponding thereto, and reflecting the compensation value at each pixel for the input gradation at each pixel to reflect the electron emission. An inter pixel uniformity compensation device of an electron emission panel having a compensation unit for driving a panel. The method of claim 19, In the output gray scale measurement unit, the uniformity compensation device between the pixels of the electron emission panel for measuring the output gradation by measuring the emission current output from the electron emission source that is electrically connected to the scan electrode or data electrode. The method of claim 19, In the output gray scale measurement unit, the uniformity compensation device between the pixels of the electron emitting panel for measuring the output gray scale by measuring the brightness output from each pixel. The method of claim 19, The compensation unit includes an electron emission control unit including a compensation control unit that obtains the compensation value in all pixels for each input gradation while sequentially increasing the input gradation from an input gradation having a minimum gradation weight to an input gradation having a maximum gradation weight. Panel-to-pixel uniformity compensation device. The method of claim 22, In the compensation controller, a specific input gradation to be displayed on all the pixels is a measurement input gradation, and the output gradation at the pixel having the maximum output gradation is the minimum output gradation from the output gradation according to the measurement input gradation. And an input gradation such as an output gradation of a pixel is determined as a compensation reference gradation of the measurement input gradation. The method of claim 23, wherein The compensation reference gradation is obtained from an input gradation having an output gradation equal to the output gradation of a pixel having a minimum output gradation with respect to the measurement input gradation in each pixel. An inter pixel uniformity compensation device of an electron emission panel determined from a subtracted value. The method of claim 24, And the compensation control unit generates a compensation table formed for each input gray level by a coordinate value of each pixel and a compensation value corresponding to the coordinate value. The method of claim 25, And the compensator further comprises first storage means for storing the compensation table. The method of claim 26, An inter-pixel uniformity compensation device of an electron emission panel, wherein the first storage means is made of nonvolatile ROM (Read Only Memory). The method of claim 27, And the compensator further comprises second storage means for temporarily storing the compensation table and enabling faster access than the first storage means. The method of claim 28, An inter-pixel uniformity compensating device of an electron emission panel, wherein the second storage means comprises a random access memory (RAM). The method of claim 25, And the compensation unit further comprises an image filter for changing an input gradation to be displayed on each pixel to a compensation reference gradation corresponding to each input gradation when the compensation gradation is to display an input gradation corresponding to each pixel. Uniformity compensation device between pixels of emission panel. The method of claim 25, The compensation table divides the entire input gradation into a plurality of gradation intervals, obtains a compensation value in each pixel for each gradation interval, and then, for each gradation interval, The uniformity compensation device between pixels of the electron emission panel formed by the compensation value corresponding to the coordinate value. The method of claim 31, wherein And the compensation value in each of the gradation sections is determined as the compensation value of the highest input gradation within each gradation section. 33. The method of claim 32, In the compensation control unit, when it is desired to display each input gradation on each pixel, an electron emission panel in which a compensation value for each input gradation is set to a value obtained by interpolation from the compensation value for each gradation section. Inter-pixel uniformity compensation device. The method of claim 31, wherein And the compensation value in each of the gradation sections is determined as the compensation value of the intermediate input gradation within each gradation section. The method of claim 31, wherein And the compensation value in each of the gradation sections is determined by an arithmetic mean of the compensation values for all input gradations in each gradation section. The method of claim 23, wherein When the driving controller is to display each input gradation on each pixel, a compensation display gradation is obtained by reflecting the compensation value in the compensation reference gradation corresponding to each input gradation, and according to the compensation display gradation The uniformity compensation device between pixels of the electron emission panel generating a compensation drive signal for driving the electron emission panel. The method of claim 36, And a data driving control unit for driving by pulse width modulation by the driving control unit by a pulse width obtained by adding a pulse width corresponding to the compensation value to a pulse width corresponding to the compensation reference gray scale. Liver uniformity compensation device. The method of claim 36, The drive control unit, And a data driving control unit configured to drive by amplitude modulation based on the amplitude obtained by adding the amplitude corresponding to the compensation value with respect to the amplitude corresponding to the compensation reference gradation.

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