KR20090073887A - Color electric paper display device and driving method thereof - Google Patents

Abstract

A color electric paper display device and a driving method thereof are provided to install a CLC color filter substrate, thereby realizing an image having improved reflection brightness. The second substrate(110) comprises an RGB(Red, Green, Blue) CLC(Colesteric Liquid Crystal) color filter(115) and a common electrode(117). The RGB CLC color filter corresponds to a pixel electrode(105) formed on a unit pixel area of the first substrate(100). An EPD film(120) is installed between the first substrate and the second substrate. A plurality of microcapsules(122) forming an electrophoretic device is sealed together with a binder(121) to form an EP film.

Description

COLOR ELECTRIC PAPER DISPLAY DEVICE AND DRIVING METHOD THEREOF

The present invention relates to a color EPD (Color Electric Paper Display) device and a driving method thereof, and more particularly, to a color EPD device having a CLC (Cholesteric Liquid Crystal) color filter substrate for improving reflection brightness and It relates to a driving method.

Recently, EPD devices have been in the spotlight as display devices that are comfortable to read without being stressed, such as e-books and e-papers. Such EPD devices are required to be thin, lightweight, durable, and easy to read so that content can be viewed as printed. In addition, as the color content is gradually increased, the EPD device is required to display the content in color. As a color EPD device that can satisfy various consumer's needs, a reflective color display device that can reduce power consumption without a backlight can be used.

In this regard, an EPD device using an electrophoretic device is known as a reflective display device. Hereinafter, an EPD device using a microcapsule type electrophoretic device will be described.

1 is a view schematically showing a cross-sectional structure of a color EPD device according to one example of the prior art.

As shown in Fig. 1, the color EPD apparatus includes a color filter substrate 1 having color filters 3 of R, G, and B, a TFT array substrate 10 having a thin film transistor TFT, and two substrates. It includes the film-shaped EPD film 5 formed in between. Here, the EPD film 5 may include an adhesive layer 6a formed on at least one side.

Here, the TFT array substrate 10 is formed in a four-layer structure. The first layer closest to the EPD film 5 is formed of a plurality of pixel electrodes P. As shown in FIG. The second and third layers each comprise an insulating layer (not shown) each comprising a plurality of TFTs corresponding to any one of the pixel electrodes P in a one-to-one relationship. In the second layer, the drain electrode D and the source electrode S corresponding to any one of the TFTs are formed in a one-to-one relationship. In the third layer, gates G corresponding to any one of the TFTs are formed in a one-to-one relationship. The source electrode S of each TFT is connected to the corresponding pixel electrode P. As shown in FIG. The fourth layer, which is the lowest layer, is a base-body layer made of glass formed to integrally support the first to third layers.

The color filter substrate 1 is formed on a transparent plastic substrate 2 made of polyethylene terephthalate (PET) or the like, and formed on the plastic substrate 2 and corresponds to the pixel electrode P of the TFT array substrate 10, respectively. Color filter (3) in which resists of red (R), green (G), and blue (B) are sequentially formed on a black matrix (not shown) that partitions an area of a black matrix and a plastic substrate (2) partitioned by a black matrix And a facing electrode 4 made of a transparent conductive film formed on the black matrix and the color filter 3 facing the pixel electrode P of the TFT array substrate 10.

In addition, the film-like EPD film 5 includes a microcapsule 7 spreading inwardly and a binder 6 made of a polymer filled between the microcapsules 7 to bond the microcapsules 7. . Each microcapsule 7 reaches a size of about 40 μm, and a solvent (not represented) made of IPA (isopropyl alcohol) or the like is encapsulated by encapsulation inside each microcapsule 7. At this time, in the solvent, white particles 8, which are titanium oxide-based white pigments having nano-sizes, and black particles 9, which are nano-sized carbon-based black pigments, are spread by a dispersion method, and each white particle 8 is dispersed. It has a negative polarity and each black particle 9 has a positive polarity.

Through this structure, for example, the light transmitted through the color filter 3 of green (G) is reflected by each microcapsule 7 in a white display state lying on the pixel electrode P, and the color of G It is transmitted to the human eye through the filter (3). Eventually, green can be recognized by this principle.

2 is a view showing a cross-sectional structure of a color EPD apparatus employing a film filter substrate according to another example of the prior art.

As shown in Fig. 2, the color EPD apparatus is composed of a color filter substrate 20, an EPD substrate 30, and a TFT array substrate 40, and each substrate is sequentially stacked by adhesive layers 23 and 31a. It is formed by lamination in the form. Here, the color filter substrate 20 includes a color filter 22 in which red (R), green (G), and blue (B) resists are sequentially arranged and formed on the transparent substrate 21, and the EPD substrate ( 30 is formed by forming the facing electrode 27 on the transparent substrate 26 and the electrophoretic element consisting of the microcapsules 32 and the binder 31 thereon, the TFT array substrate 40 is a transparent substrate or A TFT element formed on a stainless steel foil is formed to correspond to each color pixel of the color filter substrate 20.

However, in the color EPD apparatus according to the above two examples, since the color filters of R, G, and B sequentially arranged on the color filter substrates 1 and 20 are formed of a resist, each of the color filters of R, G, and B is formed. Each time, the photolithography process such as coating (or coating), exposure, development, etc. is repeated every time, which causes a lot of trouble in the process, and in particular, more effort is required when forming a color filter on a transparent substrate rather than a glass substrate. It is also a waste of money and time.

Above all, the color EPD device having the above structure absorbs 2/3 of the incident light, that is, incident light, from the color pixels of R, G, and B, respectively, and thus 1/3 of the black / white EPD device. It has a reflection brightness of 3 or less, which deteriorates the visibility in realizing the image.

The present invention has been made to improve the above problems, the object of which is to apply a reflection type CLC color filter to the color EPD device to improve the reflection brightness of the R, G, B color filters, through which the color The present invention provides a color EPD device and a driving method thereof for implementing an image in an EPD device.

The color EPD device according to the first embodiment of the present invention for achieving the above object is formed in a plurality of gate lines and data lines that are formed to cross each other to define a unit pixel region, and the intersection region of the gate line and the data line A first substrate comprising a thin film transistor and a pixel electrode formed in the unit pixel region; Red (R), green (G), and blue (B) CLC color filters respectively corresponding to the pixel electrodes formed on the unit pixel region of the first substrate, and formed on the color filters to face the pixel electrodes. A second substrate including a common electrode; A plurality of microcapsules provided between the first substrate and the second substrate and constituting the electrophoretic device may be composed of an EPD film sealed with a binder to form a film.

In addition, the driving method of the color EPD device according to the first embodiment of the present invention includes a plurality of gate lines and data lines crossing and being formed to define a unit pixel area, and a thin film transistor formed at an intersection area of the gate line and data line. A first substrate including a pixel electrode formed in the unit pixel region; Red (R), green (G), and blue (B) CLC color filters respectively corresponding to pixel electrodes formed on the unit pixel region of the first substrate, and formed on the color filters to face the pixel electrodes. A second substrate including a common electrode; A color EPD device provided between the first substrate and the second substrate, wherein the plurality of microcapsules constituting the electrophoretic device are sealed together with a binder to form a film, the color EPD apparatus comprising: a pixel electrode of the first substrate; Applying a voltage to the common electrode of the second substrate to move the white particles of the microcapsules in the direction of the CLC color filter, the light of a specific wavelength range reflected through the CLC color filter and the white of the microcapsules after passing through the same CLC color filter Mixing the light reflected by the particles to produce a white image; And applying a voltage to the pixel electrode of the first substrate and the common electrode of the second substrate to move the black particles of the microcapsule in the direction of the CLC color filter to reflect light of a specific wavelength band reflected through the CLC color filter. And absorbing the light transmitted through the CLC color filter into the black particles of the microcapsules to implement an image of a specific color.

In addition, a color EPD device according to a second embodiment of the present invention includes a plurality of gate lines and data lines crossing and forming each other to define a unit pixel area, a thin film transistor formed at an intersection area of the gate line and data line, A first substrate including a pixel electrode formed in the unit pixel region; CLC color filters of red (R), green (G), blue (B), and white (W) corresponding to pixel electrodes formed on the unit pixel region of the first substrate, and formed on the color filter A second substrate including a common electrode facing the pixel electrode; A plurality of microcapsules provided between the first substrate and the second substrate and constituting the electrophoretic device may be composed of an EPD film sealed with a binder to form a film.

In addition, one driving method of the color EPD device according to the second embodiment of the present invention may be formed by crossing and forming a plurality of gate lines and data lines defining unit pixel regions, and intersecting regions of the gate lines and data lines. A first substrate including a formed thin film transistor and a pixel electrode formed in the unit pixel region; CLC color filters of red (R), green (G), blue (B), and white (W) corresponding to pixel electrodes formed on the unit pixel region of the first substrate, and formed on the color filter A second substrate including a common electrode facing the pixel electrode; A color EPD device provided between the first substrate and the second substrate, wherein the plurality of microcapsules constituting the electrophoretic device are sealed together with a binder to form a film, the color EPD apparatus comprising: a pixel electrode of the first substrate; Applying a voltage to the common electrode of the second substrate to move the white particles of the microcapsules in the direction of the CLC color filter, the light of a specific wavelength range reflected through the CLC color filter and the white of the microcapsules after passing through the same CLC color filter Mixing the light reflected by the particles to produce an image of white; And applying a voltage to the pixel electrode of the first substrate and the common electrode of the second substrate to move the black particles of the microcapsule in the direction of the CLC color filter to reflect light of a specific wavelength band reflected through the CLC color filter. And absorbing the light transmitted through the CLC color filter into the black particles of the microcapsules to implement an image of a specific color.

In addition, another driving method of the color EPD device according to the second embodiment of the present invention includes a plurality of gate lines and data lines that cross and form each other to define a unit pixel region, and an intersection region of the gate lines and data lines. A first substrate including a thin film transistor formed on the substrate and a pixel electrode formed on the unit pixel region; CLC color filters of red (R), green (G), blue (B), and white (W) corresponding to pixel electrodes formed on the unit pixel region of the first substrate, and formed on the color filter A second substrate including a common electrode facing the pixel electrode; A color EPD device provided between the first substrate and the second substrate, wherein the plurality of microcapsules constituting the electrophoretic device are sealed together with a binder to form a film, the color EPD apparatus comprising: a pixel electrode of the first substrate; A voltage is applied to the common electrode of the second substrate to move the white particles of the microcapsules in the direction of the CLC color filters of R, G, and B to transmit light of a specific wavelength band reflected through the CLC color filter and through the same CLC color filter. Then mixing the light reflected by the white particles of the microcapsules to produce an image of white; And applying a voltage to the pixel electrode of the first substrate and the common electrode of the second substrate to move the black particles of the microcapsule in the direction of the CLC color filter of W, so that visible light of all wavelengths transmitted through the CLC color filter is applied to the microcapsules. It is characterized by comprising the step of absorbing the black particles to implement a black image.

As a result of the above configuration and driving method, the color EPD device according to the present invention has a simplified process for forming a color filter substrate as compared to the conventional color EPD device, and also has a CLC color filter substrate, so that the reflected luminance is higher than that of the conventional color EPD device. It is possible to realize an improved image.

Hereinafter, the configuration and driving method will be described in more detail with reference to the accompanying drawings.

3 is a cross-sectional view illustrating pixels of a color EPD device according to a first embodiment of the present invention.

As shown in FIG. 3, in the color EPD device according to the first embodiment of the present invention, a unit pixel area is defined by crossing a plurality of gate lines and a data line, and formed at an intersection area of the gate line and the data line. A TFT array substrate 100 (hereinafter referred to as a first substrate) including a TFT and a pixel electrode 105 formed in the unit pixel region, and a red (R) corresponding to the unit pixel on the first substrate 100, respectively. ), A color filter substrate 110 having a CLC (Colesteric Liquid Crystal) color filter 115 of green (G) and blue (B) and including a common electrode 117 facing the pixel electrode 105 ( Hereinafter, a plurality of microcapsules 122 formed between the second substrate) and the first substrate 100 and the second substrate 110 to form an electrophoretic device are sealed together with the binder 121 to form an EPD. And the membrane 120. Here, the EPD film 120 may include an adhesive layer 121a formed on at least one side.

First, the first substrate 100 is formed on a stainless steel (SUS) substrate 101 or a plastic substrate by crossing each other, a plurality of gate lines and data lines defining unit pixel regions, and the gate lines and data. A pixel electrode 105 formed in a unit pixel region defined by a line, and a TFT formed in a region where the gate line and the data line cross each other. In this case, when the first substrate 100 is formed using the plastic substrate, the process must be performed at a low temperature of about 150 degrees, so that the SUS substrate 101 can be more stabilized than the plastic substrate. It has a better advantage in terms of reliability.

In addition, on the SUS substrate 101 constituting the first substrate 100, a gate line is formed in a horizontal direction, a gate electrode G extending to the gate line to form a part of the TFT is formed, and the gate electrode. An insulating film 102 is formed on the SUS substrate 101 on which (G) is formed. On the insulating film 102, a data line crossing the gate line orthogonal to the gate line, a drain electrode D extending to the data line and partially overlapping the gate electrode G, and a drain electrode D thereof. A source electrode S is formed on the gate electrode G so as to face each other. In addition, the passivation layer 103 is formed on the data line, the source electrode S, and the drain electrode D, and the pixel electrode 105 is formed on the passivation layer 103 of the unit pixel region. 105 is connected to the source electrode S of the TFT via the contact hole 104 on the protective film 103.

On the other hand, the second substrate 110 and the black matrix 113 (black matrix) partitioning a region facing the pixel electrode 105 formed in the unit pixel of the first substrate 100 on the plastic transparent substrate 111 And a CLC color filter 115 formed on the transparent substrate 111 in a region partitioned by the black matrix 113 and corresponding to the unit pixels on the first substrate 100 and implementing colors of R, G, and B, respectively. And a common electrode 117 formed on the black matrix 113 and the CLC color filter 115 to form an electric field facing the pixel electrode 105 on the first substrate 110.

Here, the transparent substrate 111 may be a process after a separate H ₂ (hydrogen) plasma treatment to improve the coating property of the CLC.

In addition, the CLC herein is a material (hereinafter, blue mixture) formulated to have a reflection function of a corresponding blue wavelength before and after 460 nm in initial orientation, for example, a 85.1% nematic LC having a reactive group (reactive) mesogene) and about 14% of the chiral dopant having reactive groups and exhibiting conformationality upon absorption of light. In this case, the blue mixture may further include a photoinitiator for the photoreaction, and other additives including a solvent and a surfactant for controlling the coatability and thickness. The blue mixture thus formed has a characteristic that the wavelength range of reflection gradually increases by UV exposure.

In order to realize the R, G, and B subpixels, the blue mixture is coated on the transparent substrate 111 partitioned by the black matrix 113, and then a mask is applied to ultraviolet (UV) rays having a main wavelength band of 365 nm or more in air. Exposure is performed by covering a portion of the blue pixel by a coating of the blue mixture with a mask and firstly exposing the remaining blue pixels to the time when the green color is realized to form green pixels, and the green pixels. Some of the parts are covered with a mask and secondly exposed to the exposed green pixels to form red pixels. As a result, the CLC color filter 115 may be formed on the transparent substrate 111 to reflect R, G, and B colors or mixed colors of R, G, and B colors through reflection of light. have.

Then, irradiate UV with UV lamps having a main wavelength of 365 nm or less on all R, G, and B CLC color filters 115 formed according to the UV exposure amount, or N2 with the same UV lamp as the color implementation. When exposed in the atmosphere, the curing reaction of the reactive liquid crystal occurs, the CLC color filter 115 is stabilized, it is necessary to properly adjust the curing wavelength and exposure atmosphere so that the color previously implemented is not affected.

CLC is a type of liquid crystal in which the liquid crystal molecules form a helical structure. If the spiral direction is right, it is divided into right handed CLC (R-CLC) and the left hand direction is left handed CLC (L-CLC). The spiral structure has a period, that is, a pitch and reflects light of a specific wavelength corresponding to the pitch. Therefore, R-CLC reflects the right circular polarization of the wavelength and L-CLC reflects the left circular polarization of the wavelength.

Therefore, in view of this point, the CLC color filter 115 of the present invention may be formed of a CLC having any one of R-CLC and L-CLC, but on the other hand, the reflection efficiency for each color In order to increase the R-CLC and L-CLC it is preferable to form a stack.

The common electrode 117 is formed on the plastic substrate 111 on which the CLC color filter 115 and the black matrix 113 are formed to face the pixel electrode 105 of the first substrate 100. have.

In addition, an EPD film 120 is formed between the first substrate 100 and the second substrate 110. The EPD film 120 is formed by sealing a plurality of microcapsules 122 constituting the electrophoretic device by the binder 121. The EPD film 120 is laminated when the second substrate 110 is formed or when the first substrate 100 is formed. It is laminated to form the EPD film 120. In this case, the EPD 120 includes an adhesive layer 121a formed on at least one side.

Here, the microcapsules 122 include white particles 124 and black particles 123 having different charge values, such that the pixel electrode 105 of the first substrate 100 is included. ) And the white particles 124 and the black particles 123 in the microcapsules 122 are charged to the two electrodes 105 and 117 according to the voltage applied to the common electrode 117 of the second substrate 110. The light of a specific wavelength band transmitted through the CLC color filter 115 on the second substrate 110 is reflected or absorbed again.

Hereinafter, an example of implementing an image using a color EPD device having the above configuration will be described.

FIG. 4A is a diagram illustrating a case where a white background screen is implemented on a display of a color EPD device.

As shown in FIG. 4A, when a screen serving as a background is implemented in white, the screen is applied to the pixel electrode 105 on the first substrate 100 and the common electrode 117 on the second substrate 110. The white particles 124 in the microcapsules 122 forming the EPD film 120 by adjusting the voltage to the R, G, and B CLC color filters 115a, 115b, and 115c on the second substrate 110. All will be moved.

In this case, the light incident from the outside is reflected by the light of R through the CLC color filter 115a of R, the light of the G / B wavelength band transmitted through the CLC color filter 115a of R is the microcapsules 122 Is reflected through the white particles 124.

The light incident from the outside is reflected by the G light through the CLC color filter 115b of G, and the light of the R / B wavelength band transmitted through the CLC color filter 115b of the G is white of the microcapsules 122. Reflected through the particles 124.

In addition, the light of B is reflected from the light incident from the outside through the CLC color filter 115c of B, and the light of R and G except for the light having the wavelength of B is the microcapsules 122 of the microcapsule 122. It is reflected by the white particles 124.

As a result, white light (WHITE) generated by reflecting through the CLC color filters 115a, 115b, and 115c of the pixels R, G, and B, and light reflected through the white particles 124 of the microcapsules 122 is generated. White light (WHITE) generated by these processes may be mixed to form white light having a relatively high luminance.

 FIG. 4B is a diagram showing a low luminance white background image on a display of a color EPD device.

As shown in FIG. 4B, when the screen serving as a background is implemented to have a low luminance white color, the pixel electrode 105 on the first substrate 100 and the common electrode 117 on the second substrate 110 are provided. ), The black particles 123 in the microcapsules 122 forming the EPD film 120 are controlled by the voltage applied to the R, G, and B CLC color filters 115a, 115b, and 115c on the second substrate 110. Will be moved in both directions.

In this case, the light incident from the outside is reflected by the light of R through the CLC color filter 115a of R, the light of the G / B wavelength band transmitted through the CLC color filter 115a of R is the microcapsules 122 Is absorbed through the black particles 123.

The light incident from the outside is reflected by the G light through the CLC color filter 115b of G, and the light of the R / B wavelength band transmitted through the CLC color filter 115b of the G is black of the microcapsules 122. Is absorbed by the particles 123.

In addition, the light of B is reflected from the light incident from the outside through the CLC color filter 115c of B, and the light of R and G except for the light having the wavelength of B is the microcapsules 122 of the microcapsule 122. Absorbed by the black particles 123.

This is reflected by only the CLC color filters 115a, 115b, and 115c of the pixels R, G, and B, which generate white light (WHITE). Thus, as compared with FIG. Will form.

 FIG. 4 (c) is a diagram illustrating a red color image on a high-brightness background screen of white on a display of a color EPD device.

As shown in FIG. 4C, when a red image is to be implemented on a white high luminance screen as a background, the pixel electrode 105 on the first substrate 100 and the second substrate 110 are common to each other. The microcapsule 122 forming the EPD film 120 in the CLC color filter 115b of G and the CLC color filter 115c of B on the second substrate 110 by adjusting the voltage applied to the electrode 117. The white particles 124 within are moved in the direction of the CLC color filter 115 on the second substrate 110, while the EPD film 120 is formed in the CLC color filter 115a of R on the second substrate 110. The black particles 123 in the microcapsules 122 are moved in the direction of the CLC color filter 115 on the second substrate 110.

In this case, the light incident from the outside is reflected by the light of R through the CLC color filter 115a of R, the light of the G / B wavelength band transmitted through the CLC color filter 115a of R is the microcapsules 122 Is absorbed through the black particles 123.

The light incident from the outside is reflected by the G light through the CLC color filter 115b of G, and the light of the R / B wavelength band transmitted through the CLC color filter 115b of the G is white of the microcapsules 122. Reflected through the particles 124.

In addition, the light of B is reflected from the light incident from the outside through the CLC color filter 115c of B, and the light of R and G except for the light having the wavelength of B is the microcapsules 122 of the microcapsule 122. It is reflected by the white particles 124.

As a result, the white particles 124 of the microcapsules 122 after passing through the light generated through the G and B CLC color filters 115b and 115c and through the G and B CLC color filters 115b and 115c. The light reflected through) is mixed to generate white light, while the light of R is reflected through the CLC color filter 115a of R, and the G / B wavelength light transmitted through the CLC color filter 115a of R is The red image may be realized by being absorbed by the black particles 123 of the microcapsules 122 so that the red image may be realized on the white background screen having high brightness.

Of course, this is only one example, so if properly applied, green and blue images can be realized on a high brightness white background, and further, red, green and blue on a high brightness white background. Any number of images can be implemented with any combination of images.

However, the color EPD device according to the first embodiment of the present invention as described above includes a disadvantage that black cannot be implemented.

Hereinafter, a color EPD device according to a second embodiment of the present invention will be described.

5 is a cross-sectional view illustrating a pixel of a color EPD device according to a second embodiment of the present invention.

As shown in FIG. 5, in the color EPD device, a plurality of gate lines and data lines cross each other to define a unit pixel region, and a TFT formed at an intersection region of the gate line and data line and a pixel formed in the unit pixel region. Red (R), green (G), and blue (corresponding to the TFT array substrate 200 (hereinafter referred to as a first substrate) including the electrode 205 and the unit pixels on the first substrate 200, respectively) B), a color filter substrate 210 (hereinafter referred to as a second substrate) comprising a CLC color filter 215 of the bag W and a common electrode 217 facing the pixel electrode 205; A plurality of microcapsules 222 provided between the first substrate 200 and the second substrate 210 to form an electrophoretic device include an EPD film 220 sealed with the binder 221 to form a film. have. Here, the EPD film 220 includes an adhesive layer 221a formed on at least one side.

First, the first substrate 200 is formed by crossing each other on the SUS substrate 201 or the plastic substrate to define a unit pixel region, and a unit pixel defined by the gate line and the data line. A pixel electrode 205 formed in the region, and a TFT formed in the region where the gate line and the data line intersect. In this case, when the first substrate 200 is formed using the plastic substrate, the process must be performed at a low temperature of about 150 degrees, so that the SUS substrate 201 can be more stabilized than the plastic substrate. It has a better advantage in terms of reliability.

Incidentally, a gate line is formed in the horizontal direction on the SUS substrate 201 constituting the first substrate 200, a gate electrode G extending to the gate line to form a part of the TFT is formed, and the gate electrode The insulating film 202 is formed on the SUS substrate 201 in which (G) was formed. On the insulating film 202, a data line that intersects the gate line orthogonal to the gate line, a drain electrode D that extends to the data line and partially overlaps the gate electrode G, and a drain electrode D thereof. A source electrode S is formed on the gate electrode G so as to face each other. In addition, the passivation layer 203 is formed on the data line, the source electrode S, and the drain electrode D, and the pixel electrode 205 is formed on the passivation layer 203 of the unit pixel region. 205 is connected to the source electrode S of the TFT via a contact hole (not shown) on the protective film 203.

On the other hand, the second substrate 210 is a black matrix 213 partitioning an area facing the pixel electrode 205 formed on the unit pixel of the first substrate 200 on the transparent substrate 211, and the black matrix A CLC color filter 215 formed on the transparent substrate 211 in a region partitioned by 213 to implement R, G, B, and W colors corresponding to the unit pixels on the first substrate 200, and A common electrode 217 is formed on the black matrix 213 and the CLC color filter 215 to form an electric field facing the pixel electrode 205 on the first substrate 200.

Here, the transparent substrate 211 may be made after a separate H ₂ (hydrogen) plasma treatment to improve the coating property of the CLC.

Here, the CLC is a material (hereinafter referred to as a blue mixture) formed to have a reflecting function of a corresponding blue wavelength before and after 460 nm in the initial orientation, for example, 85.1% nematic LC having a reactive group ( reactive mesogene, and about 14% of chiral dopants that have reactive groups and show conformationality due to absorption of light. In this case, the blue mixture may further include a photoinitiator for the photoreaction, and other additives including a solvent and a surfactant for controlling the coatability and thickness. The blue mixture thus formed has a characteristic that the wavelength range of reflection gradually increases by UV exposure.

In order to realize the R, G, B, and W subpixels, a blue mixture is coated on the transparent substrate 211 partitioned by the black matrix 213, and then a mask is applied to ultraviolet rays having a main wavelength band of 365 nm or more in air. ), A part of the blue pixel is covered by a coating of the blue mixture with a mask, and then the first exposure is performed until the green color is applied to the remaining exposed blue pixels to form a green pixel. Some of the pixels are covered with a mask and subsequently further exposed to the exposed green pixels to form a red pixel, and some of the red pixels are covered with a mask and further exposed to the third exposed red pixels. In this case, white pixels capable of transmitting visible light in all wavelength bands may be formed. As a result, the color of R, G, B, and W, or the color of R, G, B, and W, and the EPD function are added through the reflection of light on the transparent substrate 211 to realize black. CLC color filter 215 may be formed.

Then, irradiate UV with UV lamps having a main wavelength of 365 nm or less on all R, G, and B CLC color filters 215 formed according to the UV exposure amount, or N2 with the same UV lamp as the color implementation. When exposed in the atmosphere, the curing reaction of the reactive liquid crystal occurs, the CLC color filter 215 is stabilized, it is necessary to properly adjust the curing wavelength and exposure atmosphere so that the color previously implemented is not affected.

CLC is a kind of liquid crystal in which the liquid crystal molecules form a spiral arrangement. The spiral is divided into R-CLC when the spiral direction is right and L-CLC when the spiral direction is left. The spiral structure of the CLC has a period, that is, a pitch. It has a feature that reflects light of a specific wavelength. Therefore, R-CLC reflects the right circular polarization of the wavelength and L-CLC reflects the left circular polarization of the wavelength.

Therefore, in view of this point, the CLC color filter 215 of the present invention may be formed of a CLC having any one of R-CLC and L-CLC, but on the other hand, the reflection efficiency for each color In order to increase the R-CLC and L-CLC it is preferable to form a stack.

The common electrode 217 is formed on the plastic substrate 211 on which the CLC color filter 215 and the black matrix 213 are formed to generate an electric field facing the pixel electrode 205 of the first substrate 200. .

In addition, an EPD film 220 is formed between the first substrate 200 and the second substrate 210. The EPD film 220 is formed by sealing a plurality of microcapsules 222 constituting the electrophoretic device by the binder 221 and is laminated when the second substrate 210 is formed or when the first substrate 200 is formed. It is laminated to form the EPD film 220. In this case, the EPD film 220 includes an adhesive layer 221a formed on at least one side.

Here, the microcapsules 222 include white particles 224 and black particles 223 having different charge values, such that the pixel electrode 205 and the second substrate 210 of the first substrate 200 are included. The white particles 224 and the black particles 223 in the microcapsules 222 are charged to the two electrodes 205 and 217, respectively, according to the voltage applied to the common electrode 217 of the CLC color on the second substrate 210. The light reflects or absorbs light of a specific wavelength band transmitted through the filter 215 again.

Hereinafter, an example of implementing an image using a color EPD device according to the second embodiment of the present invention will be described.

FIG. 6 (a) is a diagram showing when a white background screen is implemented on a display of a color EPD device.

As shown in FIG. 6A, when a screen serving as a background is implemented in white, the screen is applied to the pixel electrode 205 on the first substrate 200 and the common electrode 217 on the second substrate 210. The white particles 224 in the microcapsules 222 forming the EPD film 220 by controlling the voltage to be applied to the CLC color filters 215a, 215b, 215c of R, G, B, and W on the second substrate 200. 215d).

In this case, the light incident from the outside is reflected by the light of R through the CLC color filter 215a of R, the light of the G / B wavelength band transmitted through the CLC color filter 215a of R is the microcapsules 222 Is reflected through the white particles 224.

The light incident from the outside is reflected by the G light through the CLC color filter 215b of G, and the light of the R / B wavelength band transmitted through the CLC color filter 215b of the G is white of the microcapsule 222. Reflected through the particles 224.

In addition, the light of B is reflected from the light incident from the outside through the CLC color filter 215c of B, and the light of R and G except for the light having the wavelength band of B is the microcapsule 222. It is reflected by the white particles 224.

Through the CLC color filter 215d of W, visible light from all wavelengths of R, G, and B incident from the outside is transmitted, and the transmitted light is reflected back through the white particles 224 of the microcapsules 222. Comes out.

As a result, white light generated by reflecting through the R, G, and B CLC color filters 215a, 215b, and 215c forming the pixel, and transmitted through the R, G, and B CLC color filters 215a, 215b, and 215c. After the light reflected through the white particles 224 of the microcapsules 222 and the light reflected through the white particles 224 of the microcapsules 222 after passing through the color filter 215d of W is mixed The generated white light can form a relatively high luminance white light.

 FIG. 6 (b) is a diagram illustrating a white background screen and a black image on a display of a color EPD device.

As illustrated in FIG. 6B, when the screen serving as a background is implemented in white and a black image is implemented on the white background, the pixel electrode 205 on the first substrate 200 The voltage applied to the common electrode 217 on the second substrate 210 is adjusted to control the CLC color filter 215a of R, the CLC color filter 215b of G, and the CLC color filter B of the second substrate 210 ( The white particles 224 in the microcapsules 222 forming the EPD film 220 in 215c are moved in the direction of the CLC color filter 215 on the second substrate 200, while the W on the second substrate 210 is moved. The black particles 223 in the microcapsules 222 forming the EPD film 220 are moved in the CLC color filter 215d toward the CLC color filter 215 on the second substrate 200.

In this case, the light incident from the outside is reflected by the light of R through the CLC color filter 215a of R, and the light of the G / B wavelength band transmitted through the CLC color filter 215a of R is the microcapsule 222. Is reflected through the white particles 224.

The light incident from the outside is reflected by the G light through the CLC color filter 215b of G, and the light of the R / B wavelength band transmitted through the CLC color filter 215b of the G is white of the microcapsule 222. Reflected through the particles 224.

In addition, the light of B is reflected from the light incident from the outside through the CLC color filter 215c of B, and the light of R and G except for the light having the wavelength band of B is the microcapsule 222. It is reflected by the white particles 224.

On the other hand, light incident from the outside is transmitted through visible light of all wavelengths of R, G, and B through the CLC color filter 215d of W, and the transmitted light is transmitted by the black particles 223 of the microcapsules 222. Is absorbed.

As a result, the microcapsule 222 after passing through the light reflected through the CLC color filters 215a, 215b, and 215c of R, G, and B, and the CLC color filters 215a, 215b, and 215c of the R, G, and B. The light reflected through the white particles 224 is mixed with each other to generate white light, and after passing through the color filter 215d of W, absorbed by the black particles 223 of the microcapsules 222 to realize the white The black image is implemented on the background screen.

FIG. 6C is a diagram illustrating a red color image on a high-brightness background screen of white on a display of a color EPD device.

As shown in FIG. 6 (c), when a red image is to be implemented on a white high luminance screen as a background, the pixel electrode 205 on the first substrate 200 is common to the second substrate 210. The EPD film 220 is controlled by the CLC color filter 215b of G, the CLC color filter 215c of B, and the CLC color filter 215d of W on the second substrate 210 by adjusting the voltage applied to the electrode 217. The white particles 224 in the microcapsules 222 that form the structure are moved in the direction of the CLC color filter 215 on the second substrate 200, while the CLC color filter 215a of R on the second substrate 210 is moved. The black particles 223 in the microcapsules 222 forming the EPD film 220 are moved in the direction of the CLC color filter 215 on the second substrate 200.

In this case, the light incident from the outside is reflected by the light of R through the CLC color filter 215a of R, and the light of the G / B wavelength band transmitted through the CLC color filter 215a of R is the microcapsule 222. Is absorbed through the black particles 223.

The light incident from the outside is reflected by the G light through the CLC color filter 215b of G, and the light of the R / B wavelength band transmitted through the CLC color filter 215b of the G is white of the microcapsule 222. Reflected through the particles 224.

In addition, the light of B is reflected from the light incident from the outside through the CLC color filter 215c of B, and the light of R and G except for the light having the wavelength band of B is the microcapsule 222. It is reflected by the white particles 224.

Through the CLC color filter 215d of W, visible light from all wavelengths of R, G, and B incident from the outside is transmitted, and the transmitted light is reflected through the white particles 224 of the microcapsules 222. Comes out.

As a result, the light reflected through the CLC color filters 215b and 215c of G and B and the CLC color filters 215b and 215c of G and B are transmitted and then reflected through the white particles 224 of the microcapsules 222. The light and the light reflected by the white particles 224 of the microcapsules 222 after passing through the color filter 215d of the W are mixed with each other to generate white light, while through the CLC color filter 215a of R. The light of R is reflected and the G / B wavelength light transmitted through the CLC color filter 215a of R is absorbed by the black particles 223 of the microcapsules 222 to realize red color, thereby displaying red on a high-brightness white background. An image of can be implemented.

1 schematically illustrates a cross-sectional structure of a color EPD device according to one example of the prior art;

2 is a view showing a cross-sectional structure of a color EPD apparatus employing a film-like color filter substrate according to another example of the prior art;

3 is a cross-sectional view illustrating a pixel of a color EPD device according to a first embodiment of the present invention;

4 (a) to 4 (c) are diagrams showing an image implementation example of the color EPD device shown in FIG.

5 is a cross-sectional view illustrating a pixel of a color EPD device according to a second embodiment of the present invention;

6 (a) to 6 (c) are diagrams showing an example of implementing the image of FIG.

Claims (19)

A first gate line comprising a plurality of gate lines and data lines intersecting and formed to define a unit pixel region, a thin film transistor formed at an intersection of the gate line and data line, and a pixel electrode formed in the unit pixel region Board; Red (R), green (G), and blue (C) color liquid crystal (CLC) color filters corresponding to pixel electrodes formed on the unit pixel region of the first substrate, respectively, and are formed on the color filter. A second substrate including a common electrode facing the pixel electrode; The color EPD device is provided between the first substrate and the second substrate, the plurality of microcapsules constituting the electrophoretic device comprises an EPD film sealed with a binder to form a film. The CLC color filter of claim 1, wherein the CLC color filter of blue (B) is formed by mixing a nematic liquid crystal having a reactive group and a Kaile dopant having a reactive group and showing a conformational change by absorption of light. Color EPD device. The color EPD device of claim 2, wherein the blue color CLC color filter may further include a photo initiator, a xylene solvent, and a surfactant. The color EPD apparatus according to claim 2, wherein the CLC color filter of blue (B) reflects wavelengths of blue (B) before and after 460 nm. The color EPD device according to claim 1, wherein the CLC color filter of green (G) is formed by exposing the CLC color filter of blue (B) to a UV light of 365 nm or more for a predetermined period. The color EPD device according to claim 1, wherein the red (C) CLC color filter is formed by exposing the green (C) CLC color filter to a UV light of 365 nm or more for a predetermined period. The color EPD apparatus of claim 1, wherein the microcapsule comprises white particles and black particles charged with positive and negative charges. A first gate line comprising a plurality of gate lines and data lines intersecting and formed to define a unit pixel region, a thin film transistor formed at an intersection of the gate line and data line, and a pixel electrode formed in the unit pixel region A substrate; Red (R), green (G), and blue (C) color liquid crystal (CLC) color filters corresponding to pixel electrodes formed on the unit pixel region of the first substrate, respectively, and are formed on the color filter. A second substrate including a common electrode facing the pixel electrode; In the color EPD device provided between the first substrate and the second substrate, the plurality of microcapsules forming the electrophoretic device comprises an EPD film sealed with a binder to form a film, Applying a voltage to the pixel electrode of the first substrate and the common electrode of the second substrate to move the white particles of the microcapsules in the direction of the CLC color filter to obtain the same CLC color filter as the light of a specific wavelength range reflected through the CLC color filter. Mixing the light reflected by the white particles of the microcapsules after transmission to produce a white image; And Applying a voltage to the pixel electrode of the first substrate and the common electrode of the second substrate to move the black particles of the microcapsules in the direction of the CLC color filter to reflect light of a specific wavelength range reflected by the CLC color filter, the same CLC And absorbing the light transmitted through the color filter into the black particles of the microcapsules to implement an image of a specific color. A first gate line comprising a plurality of gate lines and data lines intersecting and formed to define a unit pixel region, a thin film transistor formed at an intersection of the gate line and data line, and a pixel electrode formed in the unit pixel region Board; Red (R), green (G), blue (B), and white (C) color liquid crystal (CLC) color filters corresponding to pixel electrodes formed on the unit pixel region of the first substrate, and the color filter A second substrate formed on and including a common electrode facing the pixel electrode; The color EPD device is provided between the first substrate and the second substrate, the plurality of microcapsules constituting the electrophoretic device comprises an EPD film sealed with a binder to form a film. The method of claim 9, wherein the CLC color filter of the blue (B) is formed by mixing nematic liquid crystal having a reactive group, and a Kaile dopant having a reactive group and showing a conformational change by absorption of light. Color EPD device. 10. The color EPD device according to claim 9, wherein the CLC color filter of blue (B) may additionally include a photoinitiator, a xylene solvent, and a surfactant. The color EPD apparatus according to claim 9, wherein the CLC color filter of blue (B) reflects wavelengths of blue (B) before and after 460 nm. The color EPD apparatus according to claim 9, wherein the CLC color filter of green (G) is formed by exposing the CLC color filter of blue (B) to a UV light of 365 nm or more for a predetermined period. The color EPD apparatus according to claim 9, wherein the red (C) CLC color filter is formed by exposing the green (C) CLC color filter to UV of 365 nm or more for a predetermined period. The color EPD device according to claim 9, wherein the CLC color filter of the bag (W) is formed by exposing the red (C) CLC color filter to UV of 365 nm or more for a predetermined period. 10. The color EPD device according to claim 9, wherein the microcapsule comprises white particles and black particles charged with positive and negative charges. A first gate line comprising a plurality of gate lines and data lines intersecting and formed to define a unit pixel region, a thin film transistor formed at an intersection of the gate line and data line, and a pixel electrode formed in the unit pixel region A substrate; Red (R), green (G), blue (B), and white (C) color liquid crystal (CLC) color filters corresponding to pixel electrodes formed on the unit pixel region of the first substrate, and the color filter A second substrate formed on the second substrate and including a common electrode facing the pixel electrode; In the color EPD device provided between the first substrate and the second substrate, a plurality of microcapsules forming an electrophoretic device comprises an EPD film sealed with a binder to form a film, The same CLC color filter as light applied to a pixel electrode of the first substrate and a common electrode of the second substrate by moving a white particle of a microcapsule in the direction of the CLC color filter to reflect light through the CLC color filter. After passing through the mixture of the light reflected by the white particles of the microcapsules to implement the image of white; And Applying a voltage to the pixel electrode of the first substrate and the common electrode of the second substrate to move the black particles of the microcapsules in the direction of the CLC color filter to reflect light of a specific wavelength range reflected by the CLC color filter, the same CLC And absorbing the light transmitted through the color filter into the black particles of the microcapsules to implement an image of a specific color. 18. The method of claim 17, wherein the image of the specific color is at least one of R, G, B, and Black. A first gate line comprising a plurality of gate lines and data lines intersecting and formed to define a unit pixel region, a thin film transistor formed at an intersection of the gate line and data line, and a pixel electrode formed in the unit pixel region A substrate; Red (R), green (G), blue (B), and white (C) color liquid crystal (CLC) color filters corresponding to pixel electrodes formed on the unit pixel region of the first substrate, and the color filter A second substrate formed on the second substrate and including a common electrode facing the pixel electrode; In the color EPD device provided between the first substrate and the second substrate, a plurality of microcapsules forming an electrophoretic device comprises an EPD film sealed with a binder to form a film, By applying a voltage to the pixel electrode of the first substrate and the common electrode of the second substrate, the white particles of the microcapsule are moved in the direction of the CLC color filters of R, G, and B to reflect light of a specific wavelength band reflected through the CLC color filter. And, after passing through the same CLC color filter to mix the light reflected by the white particles of the microcapsules to implement an image of white; And By applying a voltage to the pixel electrode of the first substrate and the common electrode of the second substrate, the black particles of the microcapsule are moved in the direction of the CLC color filter of W so that visible light of all wavelengths passing through the CLC color filter is black in the microcapsule. A method of driving a color EPD device, comprising the step of absorbing particles to produce a black image.

Images