KR20080098795A - Display device - Google Patents

Abstract

In the display device, the pixel electrodes are formed on the first base substrate, and the second base substrate faces the first base substrate. The color pixels are formed on the second base substrate in one-to-one correspondence with the pixel electrodes, and partially cover the corresponding pixel electrode. The common electrode is formed on the second base substrate to cover the color pixels. The electrophoretic layer includes a plurality of electrophoretic particles and is interposed between the pixel electrodes and the common electrode. Therefore, when one of the color pixels is expressed, the purity of the expressed color can be prevented from being lowered. As a result, display characteristics of the display device can be improved.

Description

Display device {DISPLAY APPARATUS}

1A is a plan view illustrating an electrophoretic display device according to an exemplary embodiment of the present invention.

FIG. 1B is a cross-sectional view taken along the line II ′ of FIG. 1A.

2A to 2C are cross-sectional views for describing the orientation of the electrophoretic particles shown in FIG. 1B.

3A and 3B illustrate an alignment mis margin of the electrophoretic display of FIG. 1A.

4A is a plan view illustrating a liquid crystal display according to another exemplary embodiment of the present invention.

FIG. 4B is a cross-sectional view taken along the line II-II ′ of FIG. 4A.

5A is a plan view illustrating an electrophoretic display device according to another exemplary embodiment of the present invention.

FIG. 5B is a cross-sectional view taken along the line III-III ′ of FIG. 5A.

* Description of the symbols for the main parts of the drawings *

100-1st display board 200-2nd display board

220-Color filter layer 300-Electrophoretic layer

DL-data line GL-gate line

PA1 to PA3-First to third pixel areas 701, 702, 703-Electrophoretic display

The present invention relates to a display device, and more particularly, to a display device capable of improving display characteristics.

In general, the display device receives an image signal and displays an image, and includes a cathode ray tube display device, a liquid crystal display, an electrophoretic display, and the like.

The cathode ray tube display device includes a vacuum tube therein and emits an electron beam from an electron gun to display an image. The cathode ray tube display device must have a sufficient distance for the electron beam to rotate, and thus has a disadvantage of being thick and heavy.

The liquid crystal display displays an image by using a characteristic in which liquid crystal molecules are changed in an arrangement direction by an electric field, and the electrophoretic display uses a phenomenon in which charged particles move by an electric field, that is, by using electrophoresis. Display the video. Liquid crystal displays and electrophoretic displays are thinner and lighter than cathode ray tube displays. In particular, since the electrophoretic labeling device is a reflective display device for displaying an image using external light, there is no need to provide a separate light source, and thus, it is thinner and lighter than the liquid crystal display device.

The liquid crystal display and the electrophoretic display include an array substrate and a color filter substrate coupled to the array substrate. The array substrate includes pixel electrodes arranged in a matrix and thin film transistors that respectively switch data voltages applied to the pixel electrodes. The color filter substrate includes color pixels corresponding to the pixel electrodes one-to-one and a common electrode facing the pixel electrodes. An electric field is formed between the array substrate and the color filter substrate by the potential difference between the pixel electrode and the common electrode.

Meanwhile, the liquid crystal display and the electrophoretic display reduce the intensity of the electric field during low voltage driving, thereby decreasing the contrast ratio. In particular, in the electrophoretic display, collisions occur between charged particles, so that the charged particles do not move smoothly. Therefore, the contrast ratio is further lowered than that of the liquid crystal display. Therefore, when one of the color pixels is expressed, the surrounding color pixels are expressed to decrease the purity of a single color. For example, when the red color is expressed, green and blue color pixels are expressed to lower the purity of the red color.

On the other hand, since the luminance and color visibility of the red, green and blue color pixels are different, the amount of the red, green and blue color pixels must be adjusted to achieve white balance. For this purpose, the thicknesses of the red, green and blue color pixels are formed differently. However, different thicknesses of the red, green, and blue color coordinates are not easily formed in the process, and planarization of the color filter substrate becomes poor.

An object of the present invention is to provide a display device capable of improving display characteristics.

A display device according to an exemplary embodiment of the present invention for achieving the above object includes a first base substrate, pixel electrodes, a second base substrate, color pixels, a common electrode, and an electrophoretic layer.

The pixel electrodes are formed on the first base substrate in an array form, and the second base substrate faces the first base substrate. The color pixels are formed on the second base substrate in a one-to-one correspondence with the pixel electrodes, and partially cover the corresponding pixel electrodes. The common electrode is formed on the second base substrate to cover the color pixels. The electrophoretic layer includes a plurality of electrophoretic particles and is interposed between the pixel electrodes and the common electrode.

The color pixels have at least one different area. Specifically, the pixel electrode includes red, green, and blue pixels formed in one-to-one correspondence with the pixel electrodes. The green color has the smallest area. The red, green, and blue color pixels have different areas and have the same thickness.

First, second, and third holes are formed in the red, green, and blue color pixels, respectively, and the size of the first, second, and third holes is inversely proportional to the area of the color pixels.

In addition, the display device according to another exemplary embodiment includes a first base substrate, pixel electrodes, color pixels, openings, a second base substrate, and a common electrode. The pixel electrodes are formed on the first base substrate. The second base substrate faces the first base substrate. The color pixels are formed on the second base substrate in a one-to-one correspondence with the pixel electrodes. The openings are formed on the second base substrate and are adjacent to the color pixels in parallel. The common electrode is formed on the second base substrate to cover the color pixels and the openings.

The color pixels have at least one different area. The color pixels include red color pixels, green color pixels, and blue color pixels formed in one-to-one correspondence with the pixel electrodes. The red, green, and blue color pixels have different sizes.

According to such a display device, when the color pixels partially cover the corresponding pixel electrode, when the color pixels of any one of the color pixels are expressed, there is a relatively high possibility that the color pixels provided around the expressed color pixels are expressed. Decreases. Therefore, the purity of the expressed color is prevented from decreasing.

In addition, the color pixels have different areas and have the same thickness. Therefore, the difference in color visibility of each color pixel can be reduced, and the upper surface of the second display substrate can be flattened. Thereby, the display characteristic of a display apparatus can be improved.

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

FIG. 1A is a plan view illustrating an electrophoretic display device according to an exemplary embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along the line II ′ of FIG. 1A.

1A and 1B, an electrophoretic display device 701 according to an exemplary embodiment of the present invention may include a first display substrate 100 and a second display substrate 200 facing the first display substrate 100. ), An electrophoretic layer 300 interposed between the first display substrate 100 and the second display substrate 200.

The first display substrate 100 includes a first base substrate 110, a plurality of gate lines GL, a plurality of data lines DL, thin film transistors 120, and pixel electrodes 130.

The first base substrate 110 has a plurality of pixel areas defined in an array form. However, in the exemplary embodiment of the present invention, only the first to third pixel areas PA1 to PA3 are shown. The first to third pixel areas PA1 to PA3 are sequentially arranged in the first direction D1 to form one dot area DTA.

The plurality of gate lines GL is formed on an upper surface of the base substrate 110 and extends in the first direction D1. The plurality of data lines DL extend in a second direction D2 orthogonal to the first direction D1, are insulated from and cross the plurality of gate lines GL, and the first through third lines. The pixel areas PA1 to PA3 are defined. The plurality of gate lines GL receives a gate signal and provides the gate signals to the thin film transistors 120, respectively, and the plurality of data lines DL receives the data signal to the thin film transistors 120, respectively. to provide.

The thin film transistors 120 and the pixel electrodes 130 are provided in the first to third pixel areas PA1 to PA3, respectively. The thin film transistors 120 are sequentially formed on the gate electrode 121 branched from one of the corresponding gate lines of the plurality of gate lines GL and on the gate electrode 121 (not shown). And an ohmic contact layer (not shown), a source electrode 122 branched from a corresponding one of the plurality of data lines DL, and formed on an upper surface of the ohmic contact layer, and an upper surface of the ohmic contact layer. It includes a drain electrode 123 formed in each. The pixel electrodes 130 are electrically connected to the drain electrodes 123 provided in the corresponding pixel areas of the first to third pixel areas PA1 to PA3. The thin film transistors 120 are turned on by receiving a gate-on signal from the corresponding gate line, and the turned-on thin film transistors 120 receive a data signal from the corresponding data line to correspond to the corresponding gate line. The data voltage is provided to the pixel electrode.

The first display substrate 100 further includes a gate insulating layer 141, a passivation layer 142, and an organic insulating layer 143. The gate insulating layer 141 is formed on the first base substrate 110 to cover the gate lines GL and the gate electrode 121. The passivation layer 142 and the organic insulating layer 143 are formed on the gate insulating layer 141 to cover the data lines DL and the thin film transistors 120. The organic insulating layer 160 may be formed of a photosensitive acrylic resin, and may be spaced apart from the data lines DL and the pixel electrodes 130 by a predetermined distance to planarize an upper surface of the array substrate 100.

In addition, a contact hole CH exposing the drain electrode 123 is formed in the passivation layer 142 and the organic insulating layer 143. The pixel electrodes 130 are formed on the top surface of the organic insulating layer 143 and are electrically connected to the drain electrode 123 through the contact hole CH.

The second display substrate 200 is provided on the first display substrate 100. The second display substrate 200 may include a second base substrate 210 facing the first base substrate 110, a color filter layer 220 formed on the second base substrate 210, and a common electrode 230. Include. In one embodiment of the present invention, the second base substrate 210 is made of a flexible material such as polyethylene terephthalate (PET). The common electrode 230 faces the pixel electrodes 130 and receives a common voltage. Therefore, an electric field is formed between the common electrode 230 and the pixel electrodes 130 by a potential difference between the common voltage and the data voltage. In an example of the present invention, the pixel electrodes 130 and the common electrode 230 are made of a transparent conductive material such as indium zinc oxide (IZO) or indium tin oxide (ITO).

An electrophoretic layer 300 including a plurality of electrophoretic particles is interposed between the pixel electrodes 130 of the first display substrate 100 and the common electrode 230 of the second display substrate 200. do. The plurality of electrophoretic particles include white particles 312 and black particles 313 charged with charges having different polarities. The black particles 313 and the white particles 312 move in accordance with the magnitude and direction of an electric field formed between the pixel electrodes 130 and the common electrode 230 to adjust the gray level of the pixel area. Display. The movement of the plurality of electrophoretic particles will be described in detail later with reference to FIGS. 2A to 2C.

The electrophoretic display device 701 further includes an adhesive member 400 for attaching the electrical interworking layer 300 to the first display substrate 100. The adhesive member 400 is interposed between the electrophoretic layer 300 and the first display substrate 100 to attach the electrophoretic layer 300 to the first display substrate 100. In an example of the present invention, the electrophoretic layer 300 may be formed integrally with the second display substrate 200 to be formed of one film.

The color filter layer 220 is formed on the second base substrate 210 in a one-to-one correspondence with the pixel electrodes 130 and includes color pixels partially covering the corresponding pixel electrode 130. As shown in FIG. 1B, each of the color pixels is adjacent to each of the openings exposing the second base substrate 200. In addition, as illustrated in FIG. 1A, all of the color pixels and the openings adjacent thereto are formed to extend along the second direction D2. The color pixels include at least red, green, and blue color pixels 221, 222, 223 that express color using light reflected from the white and black particles 312, 313. The red, green, and blue color pixels 221, 222, and 223 are formed on the second base substrate 210 in a one-to-one correspondence with the first to third pixel areas PA1 to PA3. The red, green, and blue color pixels 221, 222, and 223 are formed using photoresists containing red, green, and blue pigments, respectively.

In an exemplary embodiment, the red color pixel 221 is formed in the first pixel area PA1, the green color pixel 222 is formed in the second pixel area PA2, and the blue color pixel is formed. 223 is formed in the third pixel area PA3. Accordingly, red, green, and blue colors are respectively expressed in the first to third pixel areas PA1 to PA3 according to the grayscale values of the first to third pixel areas PA1 to PA3. Meanwhile, in the regions in which the red, green, and blue color pixels 221, 222, and 223 are not formed among the first to third pixel areas PA1 to PA3, the first to third pixel areas PA1 to PA3 are not formed. White or black color is expressed according to each gray value of PA3).

Meanwhile, the white, red, green, and blue colors, which are respectively expressed in the red, green, and blue color pixels 221, 222, and 223, are mixed to adjust the white balance in the dot area DTA. However, since the red, green, and blue color pixels 221, 222, and 223 have different color visibility and luminance, the amounts of the red, green, and blue pigments are respectively adjusted to achieve the white balance.

 In the exemplary embodiment of the present invention, the red, green, and blue color pixels 221, 222, and 223 have the same thickness and have different areas, thereby controlling the amount of the red, green, and blue pigments. In general, among the red, green, and blue color pixels 221, 222, and 223, the color visibility and luminance of the blue color pixel 223 are the worst, followed by the color visibility and luminance of the red color pixel 221. Appears good. On the other hand, the color visibility and luminance of the green color pixel 222 appear best among them.

Therefore, it is preferable to reduce the area of the green color pixel 222 than the areas of the red and blue color pixels 221 and 223. The areas of the red, green, and blue color pixels 221, 222, and 223 increase in the order of the green color pixel 222, the red color pixel 222, and the blue color pixel 223. In one embodiment of the present invention, the red, green and blue color pixels (221, 222, 223) preferably has an area ratio of 7: 4: 9. As a result, it is possible to reduce the difference in color visibility and luminance occurring between the red, green, and blue color pixels 221, 222, and 223.

In addition, the red, green, and blue color pixels 221, 222, and 223 have the same thickness because the white balance is adjusted by varying the areas of the red, green, and blue color pixels 221, 222, and 223. It can be formed to have. Therefore, the top surface of the second display 200 may be planarized. In addition, by adjusting the thicknesses of the red, green, and blue color pixels 221, 222, and 223, the color visibility and luminance difference generated between the red, green, and blue color pixels 221, 222, and 223 may be overcome. It is easier to adjust the area of the red, green and blue color pixels 221, 222, and 223 than in the case.

In the present embodiment, the red, green, and blue color pixels 221, 222, and 223 extend in the second direction D2 within the corresponding pixel electrode. Preferably, the red, green, and blue color pixels 221, 222, and 223 cross the center of the corresponding pixel electrode and are spaced apart from each other by a predetermined distance. The separation distances between the adjacent color pixels among the red, green, and blue color pixels 221, 222, and 223 are different from each other.

Meanwhile, the second display substrate 200 is formed on the second base substrate 210 to cover the color pixels, and reduces the step difference between an area where the color pixels are provided and an area where the color pixels are not provided. An overcoat layer 240 is further included. The overcoat layer 240 is formed on the entire surface of the second base substrate 210, and the common electrode 230 is formed on the overcoat layer 240 with a uniform thickness.

2a to 2c is a view showing the orientation of the plurality of electrophoretic particles according to the electric field.

Referring to FIG. 2A, an electrophoretic layer 300 is interposed between the pixel electrode 130 and the common electrode 230. In the embodiment of the present invention, the electrophoretic layer 300 is composed of a plurality of microcapsules 310 having a spherical shape, each microcapsule 310 is a dispersion medium 311 made of a transparent insulating liquid, the dispersion medium And a plurality of electrophoretic particles dispersed within 311. The plurality of electrophoretic particles consist of white particles and black particles 312 and 313. The white particles and the black particles 312 and 313 are charged with electric charges having different polarities.

A surfactant is added to the dispersion medium 311, and the specific gravity of the dispersion medium 311 and the white particles and the black particles 312 and 313 is almost the same to prevent precipitation by gravity. In addition, the dispersion medium 311 prevents the pulling of the white particles and the black particles 312 and 313 or the aggregation of the white particles and the black particles 312 and 313 into a large mass. .

In one embodiment of the present invention, the white particles 312 are charged with a positive charge and are made of a material such as titanium dioxide (TiO ₂ ) to have a white color. The black particles 313 are charged with a negative charge and are made of carbon powder such as carbon black to have a black color.

In the state where no electric field is formed between the pixel electrode 130 and the common electrode 230, the white particles and the black particles 312 and 313 do not have directivity, and thus the pixel electrode 130 Randomly provided between the common electrode 230 and.

Subsequently, as illustrated in FIG. 2B, when a data voltage having a positive polarity (+) with respect to the common voltage applied to the common electrode 230 is applied to the pixel electrode 130, the pixel electrode is caused by a voltage difference. An electric field is formed at 130 and the common electrode 230.

In this case, the white particles 312 charged with the positive charge move toward the common electrode 230, and the black particles 313 charged with the negative charge correspond to the pixel electrode ( 130) go to the side. As such, when an electric field having positive polarity (+) is formed between the pixel electrode 130 and the common electrode 230, the white gray level is displayed in the pixel area.

As described above, when the white gray scale is displayed, light incident through the common electrode 230 is reflected by the white particles 312, and the reflected light is again reflected through the common electrode 230. By exiting, the user can visually recognize an image of white gradation. In addition, when a color pixel is provided on the common electrode 230 to which the reflected light is emitted again, the color of the color pixel is expressed, so that the user may recognize the expressed color.

As illustrated in FIG. 2C, when a data voltage having negative polarity (−) is applied to the pixel electrode 130 with respect to the common voltage applied to the common electrode 230, the pixel electrode 130 and the common voltage are applied to the pixel electrode 130. An electric field is formed in the electrode 230.

In this case, the white particles 312 charged with the positive charge move toward the pixel electrode 130, and the black particles 313 charged with the negative charge are the common electrodes. It moves to the 230 side. As such, when an electric field having a negative polarity (−) is formed between the pixel electrode 130 and the common electrode 230, a black gray level is displayed in the pixel area.

As described above, when the black gradation is displayed, light incident through the common electrode 230 is absorbed by the black particles 313 so that light is hardly emitted through the common electrode 230. . Therefore, the color of the color pixels provided on the common electrode 230 is not expressed, and the user may recognize the image of the black gradation.

Referring back to FIG. 1B, when one of the red, green, and blue color pixels 221, 222, and 223 is expressed, the pixel electrode and the common electrode 230 corresponding to the color pixel to be expressed may be formed. An electric field having positive polarity (+) is formed therebetween, and an electric field having negative polarity (−) is formed between the pixel electrode and the common electrode 230 corresponding to the other color pixels. An example of expressing the color of the blue color pixel 223 provided in the third pixel area PA3 is described in the embodiment of the present invention.

An electric field having a negative polarity (−) is formed in the first and second pixel areas PA1 and PA2, and an electric field having a positive polarity (+) is formed in the third pixel area PA3. Accordingly, the black particles 313 move toward the common electrode 230 in the first and second pixel areas PA1 and PA2, and the white particles 312 in the third pixel area PA2. The common electrode 230 moves to the common electrode 230. Therefore, the color of the blue color pixel 223 is expressed, and the colors of the red and green color pixels 221 and 222 are not expressed. As a result, the user can visually recognize the blue color in the dot area DTA.

However, when the white and black particles 312 and 313 move, a collision occurs between the white and black particles 312 and 313 so that the white in the first and second second pixel areas PA1 and PA2. A portion of the particles 312 may move to the common electrode 230. As a result, colors of the red and green color pixels 221 and 222 are expressed in the first and second pixel areas PA1 and PA2 and are mixed with the blue color. As a result, the purity of the blue color visually recognized in the dot area DTA is lowered.

As described above, in order to prevent the purity of the blue color from decreasing, the electrophoretic display device 701 according to the exemplary embodiment of the present invention corresponds to the red, green, and blue color pixels 221, 222, and 223. And partially cover the pixel electrode. Therefore, the area occupied by the red, green, and blue color pixels 221, 222, and 223 in the first to third pixel areas PA1 to PA3 is reduced. As a result, the red, green, and blue color pixels 221, 222, and 223 may be prevented from lowering in purity of the blue color than in the case where the corresponding pixel electrodes are overlapped with each other. That is, since the area of the red and green color pixels 221 and 222 is reduced, the red and green of the light reflected by the white particles 312 in the first and second pixel areas PA1 and PA2 are reduced. This is because the light passing through the color pixels 221 and 222 is reduced. Therefore, when the color of any one of the color pixels is expressed, the purity of the expressed color can be prevented from being lowered.

3A and 3B illustrate an alignment mis margin of the electrophoretic display of FIG. 1A.

3A and 3B, when an alignment miss occurs when the first display substrate 100 and the second display substrate 200 are bonded to each other, that is, as shown in FIGS. 3A and 3B, the first display substrate 100 may be aligned. 2 When the display substrate 200 moves to the right by a predetermined distance with respect to the first display substrate 100 and is bonded to the first display substrate 100, the first display substrate 100 and the second display substrate ( Alignment miss occurs between 200). The electrophoretic display device 701 is not normally displayed until alignment between the color pixels and the corresponding pixel electrode is performed. Therefore, when the misalignment between the first display substrate 100 and the second display substrate 200 causes an alignment error between the color pixels and the pixel electrodes 130, the electrophoretic display device 701 is used. The abnormal image is displayed in.

In the present embodiment, the red, green, and blue color pixels 221, 222, and 223 extend side by side in the same direction to partially cover the corresponding pixel electrode. In addition, the red, green and blue color pixels 221, 222, and 223 cross the center of the corresponding pixel electrode and are spaced apart from each other. Accordingly, the alignment mis margin is increased than when the red, green, and blue color pixels 221, 222, and 223 are formed to completely overlap with the corresponding pixel electrode. As a result, defects due to misalignment of the first and second display substrates 100 and 200 are reduced. In the present exemplary embodiment, the alignment miss margin is a distance A between the blue color pixel 223 and the pixel electrode adjacent to the blue color pixel 223.

4A is a plan view illustrating an electrophoretic display device according to another exemplary embodiment. FIG. 4B is a cross-sectional view taken along the line II-II ′ of FIG. 4A. However, the same reference numerals are given to the same components as those shown in FIGS. 1A and 1B among the components illustrated in FIGS. 4A and 4B, and detailed description thereof will be omitted.

4A and 4B, the liquid crystal display 702 according to the present exemplary embodiment may include a first display substrate 100, a second display substrate 200 facing the first display substrate 100, and the first display substrate 100. The liquid crystal layer 600 is interposed between the first display substrate 100 and the second display substrate 200. The liquid crystal display 702 has a structure similar to the electrophoretic display 701 illustrated in FIGS. 1A and 1B except for the liquid crystal layer 600. Therefore, detailed descriptions of the first and second display substrates 100 and 200 will be omitted, and components of the electrophoretic display apparatus 701 different from those of the electrophoretic display apparatus 701 may be omitted. Explain.

The first display substrate 100 may include a first base substrate 110, a plurality of gate lines GL, a plurality of data lines DL, thin film transistors 120, pixel electrodes 130, and a gate insulating film. 141, a protective film 142, and an organic insulating film 143.

The second display substrate 200 includes a second base substrate 210, a color filter layer 220, a common electrode 230, and an overcoat layer 240, and is coupled to face the first display substrate 100. do. The second display substrate 200 is formed on the second base substrate 210 to correspond to a region where the gate lines GL, the data lines DL, and the thin film transistors 120 are formed. It further includes a black matrix 250. The black mattress 250 may be made of a light blocking material to block light leakage from the periphery of each of the first to third pixel areas PA1 to PA3.

The liquid crystal display 701 further includes a backlight unit (not shown) provided on a rear surface of the first display substrate 100 to provide light to the first display substrate 100.

The liquid crystal layer 600 is interposed between the first display substrate and the second display substrates 100 and 200 by a dropping method or a vacuum injection method. The arrangement direction of the liquid crystal molecules 610 of the liquid crystal layer 600 is changed according to the potential difference between the common electrode 230 and the pixel electrodes 130, and the light transmittance is changed according to the arrangement direction. The color pixels express each color using the light.

In this embodiment, as shown in Figs. 1A and 1B, an example of expressing the blue color pixel 223 is described. For example, the liquid crystal display 702 is a normally white TN (Twist Nematic) mode, and the liquid crystal layer 600 includes liquid crystal molecules 610 having positive dielectric anisotropy. . Each liquid crystal molecule 610 has an elliptical cross section in which the major and minor axes are different from each other. Hereinafter, the alignment direction of the liquid crystal molecules 610 will be described based on the long axis direction.

The liquid crystal display 702 may further include first and second polarizers (not shown) attached to the outside of the first and second display substrates 100 and 200, respectively. The two polarizing plates are arranged such that the absorption axes are perpendicular to each other.

In the off state of the liquid crystal display 702, the liquid crystal molecules 321 are initially aligned horizontally with respect to the first and second display substrates 100 and 200. When the liquid crystal molecules 610 are arranged in parallel with the first and second display substrates 100 and 200, the light incident on the first polarizing plate is polarized in one direction and then the liquid crystal molecules 610 are separated. A phase change is generated as it passes through the second polarizing plate. Thus, the liquid crystal display 702 maintains a white state.

When an electric field is formed between the pixel electrodes 130 and the common electrode 230, an electric field is formed in a direction perpendicular to the first and second display substrates 100 and 200, and the liquid crystal molecules 610. ) Are arranged in a direction parallel to the electric field. Thus, the liquid crystal molecules 610 are arranged in a direction perpendicular to the first and second display substrates 100 and 200. In this state, light incident on the first polarizing plate is polarized in one direction and then absorbed by the second polarizing plate, and the liquid crystal display 702 is in a black state.

The first and second pixel areas PA1 and PA2 are applied by applying a data voltage to the pixel electrodes corresponding to the red and green color pixels 221 and 222 to recognize the blue color in the dot area DTA. The liquid crystal molecules 610 are arranged in a direction perpendicular to the first and second display substrates 100 and 200. In addition, the third pixel area PA corresponding to the blue color pixel 223 is maintained in an off state so that the liquid crystal molecules 610 are arranged in the parallel direction.

On the other hand, when driving at a low voltage in order to reduce the power consumption of the liquid crystal display, the liquid crystal molecules 610 are not arranged in a direction perpendicular to the first and second display substrates 100 and 200, and are inclined. Are arranged. The red and green colors when the liquid crystal molecules 610 disposed in the first and second pixel areas PA1 and PA2 are inclined with respect to the first and second display substrates 100 and 200. Pixels 221 and 222 are expressed and mixed with the blue color. As a result, the purity of the blue color in the dot area DTA is lowered.

However, since the color pixels partially cover the corresponding pixel electrode, the probability that the light is emitted through the red and green color pixels 221 and 222 is reduced. Therefore, the probability that the red and green color pixels 221 and 222 are expressed is reduced, and as a result, the purity of the blue color expressed in the blue color pixel 233 can be prevented from being lowered.

FIG. 5A is a plan view illustrating an electrophoretic display device according to another exemplary embodiment. FIG. 5B is a cross-sectional view taken along the cutting line II-II ′ of FIG. 5A. However, the same reference numerals are given to the same components as those shown in FIGS. 1A and 1B among the components shown in FIGS. 5A and 5B, and detailed description thereof will be omitted.

5A and 5B, the electrophoretic display device 703 according to the present exemplary embodiment may include a first display substrate 100, a second display substrate 200 facing the first display substrate 100, and the second display substrate 200. An electrophoretic layer 300 is interposed between the first display substrate 100 and the second display substrate 200.

The first display substrate 100 includes a first base substrate 110, a plurality of gate lines GL, a plurality of data lines DL, thin film transistors 120, pixel electrodes 130, and a gate insulating layer. 141, a protective film 142, and an organic insulating film 143. The second display substrate 200 includes a second base substrate 210, a color filter layer 220, a common electrode 230, and an overcoat layer 240.

In the present embodiment, the red, green, and blue color pixels 225, 226, and 227 cover the corresponding pixel electrode and extend to an area where the gate lines GL and data lines DL are formed. And overlaps the gate lines GL and the data lines DL. First to third holes H1 to H3 are formed in the red, green, and blue color pixels 225, 226, and 227, respectively. Accordingly, the red, green, and blue color pixels 225, 226, and 227 partially cover the corresponding pixel electrode, and the red, green, and blue colors are formed by the sizes of the first to third holes H1 to H3. And the areas of blue color pixels 225, 226, 227 are reduced. As a result, when the blue color pixel 227 is expressed in the dot area DTA, the colors of the red and green color pixels 225 and 226 are prevented from being expressed. In addition, since the white or black color is expressed in the first to third holes H1 to H3, the purity of the blue color may be prevented from being lowered.

For example, the first to third holes H1 to H3 are formed at the centers of the red, green, and blue color pixels 225, 226, and 227 and have a rectangular shape.

The sizes of the first to third holes H1 to H3 are different from each other. The first hole H1 is formed in the red color pixel 225, and the second hole H2 larger than the first hole H1 is formed in the green color pixel 226. Thus, the green color pixel 226 has a smaller area than the red color pixel 226. In addition, the third hole H3 smaller than the first hole H1 is formed in the blue color pixel 227. Thus, the blue color pixel 227 has a larger area than the red and green color pixels 225 and 226.

For example, the sizes of the first to third holes H1 to H3 have a ratio of 3: 6: 1. When the total area of the region where the first hole H1 and the red color pixel 225 are formed is '100', the first hole H1 occupies about 30% of the total area. When the total area of the region where the second hole H2 and the green color pixel 226 are formed is '100', the second hole H2 occupies about 60% of the total area. In addition, when the total area of the region where the third hole H3 and the blue color pixel 227 are formed is '100', the third hole H3 occupies about 10% of the total area.

As the sizes of the first to third holes H1 to H3 decrease in the order of the second hole H2, the first hole H1, and the third hole H3, the red, green, and blue color pixels ( The areas of 225, 226, and 227 increase in the order of the green color pixel 226, the red color pixel 225, and the blue color pixel 227. As a result, the color visibility and luminance difference generated between the red, green, and blue color pixels 225, 226, and 227 may be reduced. Therefore, white balance can be achieved in the dot area DTA.

Meanwhile, the red, green, and blue color pixels 225, 226, and 227 have the same thickness, so that the top surface of the second display 200 may be flattened. In addition, the red, green, and blue color pixels 225, 226 may be adjusted by adjusting the thicknesses of the red, green, and blue color pixels 225, 226, and 227 to overcome the differences in color visibility and luminance of each color pixel. , 227) to overcome the difference in color visibility and luminance of each pixel by process.

In the present embodiment, an example in which the first to third holes H1 to H3 are formed in a rectangular shape is described, but may be formed in a shape other than the rectangular shape. In addition, the color pixels in which the first to third holes H1 to H3 are formed may be applied to the liquid crystal display.

According to such a display device, the color pixels partially cover the corresponding pixel electrode. Therefore, when one of the color pixels is expressed, the color is prevented from being expressed in the surrounding color pixels. As a result, the purity of the expressed color can be prevented from decreasing.

In addition, the color pixels have different areas and have the same thickness. Therefore, the difference in color visibility of each color pixel can be reduced, and the upper surface of the second display substrate can be flattened. Thereby, the display characteristic of a display apparatus can be improved.

Although described with reference to the embodiments above, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the invention as set forth in the claims below. Could be.

Claims (22)

A first base substrate; Pixel electrodes formed on the first base substrate; A second base substrate facing the first base substrate; Color pixels formed on the second base substrate in one-to-one correspondence with the pixel electrodes, and partially covering the corresponding pixel electrode; A common electrode formed on the second base substrate to cover the color pixels; And And a plurality of electrophoretic particles, the electrophoretic layer interposed between the pixel electrodes and the common electrode. The display device of claim 1, wherein the color pixels include color pixels having at least one different area. The display device of claim 2, wherein the color pixels include red, green, and blue pixels formed in one-to-one correspondence with the pixel electrodes. The display device of claim 3, wherein the red, green, and blue color pixels have the same thickness. The display device of claim 4, wherein the red, green, and blue color pixels have different areas. The display device of claim 5, wherein the green color pixel has the smallest area and the blue color pixel has the largest area. The method of claim 5, And first and third holes are formed in the red, green, and blue color pixels, respectively. The display device of claim 7, wherein the size of the first to third holes is inversely proportional to the area of the color pixels. The display device of claim 8, wherein the first to third holes have a ratio of 3: 6: 1. The method of claim 5, And wherein the red, green, and blue color pixels cross a central portion of the corresponding pixel electrode and are spaced apart from each other. The display device of claim 1, wherein the plurality of electrophoretic particles comprise a plurality of black particles and a plurality of white particles having different polarities. A first base substrate; Pixel electrodes formed on the first base substrate; A second base substrate facing the first base substrate; Color pixels formed on the second base substrate in a one-to-one correspondence with the pixel electrodes; Openings formed on the second base substrate and adjacent to the color pixels in parallel; And And a common electrode formed on the second base substrate to cover the color pixels and the openings. The display device of claim 12, wherein the openings expose the second base substrate. The display device of claim 13, wherein the color pixels include color pixels having at least one different area. The display device of claim 14, wherein the color pixels include red, green, and blue pixels formed in one-to-one correspondence with the pixel electrodes. The display device of claim 15, wherein the red, green, and blue color pixels have the same thickness. The display device of claim 16, wherein the red, green, and blue color pixels have different areas. 18. The display device according to claim 17, wherein the green color pixel has the smallest area and the blue color pixel has the largest area. The display device of claim 12, further comprising an electrophoretic layer including a plurality of electrophoretic particles and interposed between the pixel electrode and the common electrode. The display device of claim 19, wherein the plurality of electrophoretic particles comprise a plurality of black particles and a plurality of white particles having different polarities. The display device of claim 12, further comprising a liquid crystal layer interposed between the common electrode and the pixel electrode. The display device of claim 12, further comprising an overcoat layer formed between the color pixels and the common electrode.

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