Abstract:
A color filter substrate comprising a substrate, a light blocking layer on the substrate having a plurality of wells with bottoms that contact the substrate, and a plurality of channels between the wells, and a color layer material which fills the wells and channels.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATION  
       [0001]     This application claims priority to Korean Patent Application No. 2005-53103, filed on Jun. 20, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Technical Field  
         [0003]     The present disclosure relates to a color filter substrate and a method of fabricating the color filter substrate. More particularly, the present disclosure relates to a color filter substrate having an improved uniformity and method of fabricating the same.  
         [0004]     2. Discussion of the Related Art  
         [0005]     An inkjet printing method is widely used as a method of forming a color filter layer. In such a method, openings are formed through a light blocking layer which is formed on a substrate, and a color ink is sprayed onto the substrate through the openings.  
         [0006]      FIGS. 1A and 1B  are sectional views illustrating a conventional method of forming a color filter layer.  
         [0007]     Referring to  FIGS. 1A and 1B , openings  3  are formed through a light blocking layer  2 , which is formed on a substrate  1 . A color ink  4  is sprayed onto the exposed substrate  1  through the openings  3  and not sprayed onto the light blocking layer  2 . When the color ink  4  sprayed onto the exposed substrate  1  is cured under a predetermined temperature, a color filter layer  5  is formed on the substrate  1  as shown in  FIG. 1B . However, the thickness of the color filter layer  5  is uneven due to the coffee stain effect. The coffee stain effect reveals that during drying of a liquid, the interaction of surface tension and evaporation may cause an uneven distribution of material left behind. For example, when the color ink  4  having a volatile solvent is cured, a portion of the color ink  4  making contact with the light blocking layer  2  evaporates more quickly than a portion of the color ink  4  that does not make contact with the light blocking layer  2 . As a result, a color filter layer  5  is produced with an uneven thickness as shown in  FIG. 1B .  
       SUMMARY OF THE INVENTION  
       [0008]     In an exemplary embodiment of the present invention, a color filter substrate comprises a substrate, a light blocking layer, and a color layer material. The light blocking layer is formed on the substrate. The light blocking layer has a plurality of wells having bottoms that contact the substrate and a plurality of channels between the wells. A color layer material fills the wells and the channels. The wells may be arranged in a matrix of rows and columns. The color layer material in a column of the matrix may differ in color from an adjacent column of the matrix. The color layer material in a row of the matrix may differ in color from an adjacent row of the matrix.  
         [0009]     In an exemplary embodiment of the present invention, a method of fabricating a color filter substrate is provided as follows. A light blocking layer is formed on a substrate and patterned to form a plurality of openings through the light blocking layer. A plurality of channels are formed on the light blocking layer between the openings to allow each of the openings to be connected to an adjacent opening thereto. A plurality of color layers is formed on the substrate exposed through the openings and on the channels of the light blocking layer between the openings. Each of the color layers connects the openings arranged in a same line such that the color layers are substantially parallel to each other.  
         [0010]     Each of the color layers may have a different color from that of adjacent color layers thereto. A color ink is sprayed onto the substrate exposed through the openings and onto the channels of the light blocking layer between the openings to form the color layers. The openings may be substantially simultaneously formed with the channels using a single mask. The openings may be arranged in a matrix shape and the color layers connect the openings arranged either in a vertical direction or in a horizontal direction. The openings formed through the light blocking layer are connected to each other through the channels, so that the color ink sprayed onto the substrate exposed through the openings and onto the light blocking layer may flow between the openings, thereby forming a color layer with a uniform thickness.  
         [0011]     According to an exemplary embodiment of the present invention, a method of fabricating a color filter substrate includes forming a light blocking layer on a substrate, patterning the light blocking layer to form a plurality of wells through the light blocking layer, forming a plurality of channels in the light blocking layer between the wells to allow each of the wells to be connected to adjacent wells, and filling the channels and wells with a color layer material.  
         [0012]     The wells may be arranged in a matrix of rows and columns. The color layer material in a column of the matrix may differ in color from an adjacent column of the matrix. The color layer material in a row of the matrix may differ in color from an adjacent row of the matrix. The color layer material may be applied by spraying a colored ink onto the substrate exposed by the wells and the channels between the wells. The wells and channels may be formed together using a single mask. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     The above and other features of the present invention will become readily apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:  
         [0014]      FIGS. 1A and 1B  are sectional views illustrating a conventional method of forming a color filter layer;  
         [0015]      FIG. 2  illustrates a color filter substrate according to an exemplary embodiment of the present invention;  
         [0016]      FIG. 3A  is a cross-sectional view taken along line I-I′ of  FIG. 2 ;  
         [0017]      FIG. 3B  is a cross-sectional view illustrating an exemplary embodiment of the color filter substrate shown in  FIG. 3A ;  
         [0018]      FIGS. 4A  to  4 D are cross-sectional views illustrating a method of fabricating the color filter substrate shown in  FIG. 2  according to an exemplary embodiment of the invention;  
         [0019]      FIGS. 5A  to  5 D are cross-sectional views illustrating a method of fabricating the color filter substrate shown in  FIG. 2  according to an exemplary embodiment of the present invention;  
         [0020]      FIG. 6  illustrates a color filter substrate according to an exemplary embodiment of the present invention;  
         [0021]      FIG. 7  is a cross-sectional view taken along line II-II′ of  FIG. 6 ;  
         [0022]      FIG. 8  is a cross-sectional view taken along line III-III′ of  FIG. 6 ; and  
         [0023]      FIGS. 9A and 9B ,  10 A and  10 B,  11 A and  11 B and  12 A and  12 B are cross-sectional views illustrating a method of fabricating the color filter substrate of  FIG. 6  according to an exemplary embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS  
       [0024]     It will be understood that when an element or layer is referred to as being “on”, “connected to” or “coupled to” another element or layer, it can be directly on, connected or coupled to the other element or layer, or intervening elements or layers may be present.  
         [0025]     It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.  
         [0026]     Spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.  
         [0027]     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms, “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “includes” and/or “including”, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.  
         [0028]     Hereinafter, the exemplary embodiments of the present invention will be explained in detail with reference to the accompanying drawings.  
         [0029]      FIG. 2  illustrates a color filter substrate according to an exemplary embodiment of the present invention.  
         [0030]     Referring to  FIG. 2 , a color filter substrate  100  includes a substrate  10 , a light blocking layer  20 , and a color layer  50 . The color layer  50  displays a predetermined color. The light blocking layer  20  is formed on the substrate  10 . Openings  30  corresponding to pixels are formed on the light blocking layer  20  to partially expose the substrate  10 . The color layer  50  is formed on the substrate  10  exposed through the openings  30 . The light blocking layer  20  formed on the substrate  10  prevents light interference between the pixels.  
         [0031]     The color layer  50  may display various color layers, for example, a red color layer  50   r , a green color layer  50   g  and a blue color layer  50   b . The red, green and blue color layers  50   r ,  50   g  and  50   b  are alternately arranged with each other and each of the red, green and blue color layers  50   r ,  50   g  and  50   b  is arranged in a line. The light blocking layer  20  has channels  60  positioned between all wells that makeup the same color layer of the red, green and blue color layers  50   r ,  50   g  and  50   b.    
         [0032]      FIG. 3A  is a cross-sectional view taken along a line I-I′ of  FIG. 2 .  FIG. 3B  is a cross-sectional view illustrating an exemplary embodiment of the color filter substrate shown in  FIG. 3A .  
         [0033]     Referring to  FIGS. 2 and 3 A, the light blocking layer  20  through which the wells  30  are formed, is formed on the substrate  10 . The channels  60  are formed on the light blocking layer  20  between all wells that makeup the same color layer of the red, green and blue color layers  50   r ,  50   g  and  50   b . Using the inkjet method, as shown in  FIG. 3A , the red color layer  50   r  is formed on the substrate  10  exposed through the openings  30  so the red color layer  50   r  may be formed with a uniform thickness.  
         [0034]     When the red, green and blue color layers  50   r ,  50   g  and  50   b  are formed by the inkjet method, the channels  60  may have variable sizes and shapes. The channels  60  may have a concave shape such as a U-shape, a V-shape, etc. In addition, the channels  60  may have a depth that is substantially similar to or shallower than a thickness of the light blocking layer  20 . The depth of the channels  60  are determined in consideration of a function of the light blocking layer  20  that prevents light interference between adjacent pixels to improve a contrast. For example, when the light blocking layer  20  has a thickness of about 1.5 micrometers, the channels  60  may have a thickness above about 0.1 micrometers to below about 1.5 micrometers.  
         [0035]     In  FIG. 3A , the channels  60  have a width W suitable for allowing the color ink to flow into adjacent pixels. When the width W of the channels  60  is too small, the color ink sprayed onto the light blocking layer  20  may not flow into adjacent pixels because a distance between adjacent openings has become too large.  
         [0036]     As shown in  FIG. 3B , the channels  60  may have substantially the same width W as the distance between adjacent openings, so that the channels  60  may be connected with an adjacent opening thereto. The channels  60  may have a concave shape such as a U-shape, a V-shape, etc.  
         [0037]      FIGS. 4A  to  4 D are cross-sectional views illustrating a method of fabricating the color filter substrate shown in  FIG. 2 . In  FIGS. 4A  to  4 D, the same reference numerals denote the same elements in  FIGS. 3A and 3B .  
         [0038]     Referring to  FIG. 4A , the light blocking layer  20  is formed on the substrate  10 . The substrate  10  may be a transparent glass substrate and the light blocking layer  20  may be a metal layer such as chromium (Cr) or a polymer resin such as a black-colored photoresist material. When the light blocking layer  20  is made of a metal layer, the layer is formed on the substrate  10  and the openings  30  may be patterned by a photolithography process. When the light blocking layer  20  is made of a polymer resin, the resin is coated onto the substrate  10  and the openings  30  may be patterned by partially removing the polymer resin due to exposure/development of the resin.  
         [0039]     Referring to  FIG. 4B , the channels  60  are formed on the light blocking layer  20  between the openings  30 . The channels  60  may be formed by a photography process when the openings  30  are formed.  
         [0040]     Referring to  FIG. 4C , the color ink  40  is sprayed onto portions of the substrate  10  exposed by the openings  30 . The color ink  40  includes pigment determining colors and a volatile solvent. The volatile solvent of the color ink  40  evaporates when the color ink  40  sprayed onto the substrate  10  is cured. The color ink  40  is divided into red, green and blue color inks. Each of the red, green and blue color inks is separately sprayed onto the substrate  10  along a subset of the openings  30  that are arranged in the same direction.  
         [0041]     As shown in  FIG. 4C , the color ink  40  is sprayed not only onto the substrate  10  exposed through the openings  30  but also onto the light blocking layer  20  between the openings  30 , thereby forming the red, green and blue color layers  50   r ,  50   g  and  50   b  (refer to  FIGS. 2, 3A  and  3 B) each with uniform thicknesses. In a conventional color filter substrate, the color ink is sprayed only onto the substrate exposed through the openings. As a result, when the color ink sprayed onto the substrate is cured, the volatile solvent of the color ink evaporates at a different rate in accordance with a region of the substrate exposed through the openings, thereby resulting in color layers with non-uniform thicknesses. However, when the color ink  40  is successively sprayed onto the substrate  10  exposed through the openings  30  and onto the light blocking layer  20  at which the channels  60  are formed, the color ink  40  may have a uniform thickness since the color ink  40  flows between the openings  30  through the channels  60  on the light blocking layer  20 . Thus, the volatile solvent of the color ink  40  may be uniformly volatilized regardless of the regions onto which the color ink  40  is sprayed. The color ink  40  may be thickly sprayed onto the substrate  10  exposed through the openings  30  in consideration of a volume reduction of the sprayed color ink  40  when the volatile solvent of the sprayed ink  40  is volatilized.  
         [0042]     When the color ink  40  is sprayed, the color ink  40  is applied not only onto the substrate  10  exposed through the openings  30 , but also onto the light blocking layer  20  between the openings  30 . In an exemplary embodiment of the invention, the light blocking layer  20  has a thickness of about 1.5 micrometers, the color ink  40  sprayed onto the exposed substrate  10  has a thickness of about 1.6 micrometers, and the color ink  40  sprayed onto the light blocking layer  20  has a thickness of about 1.0 micrometers. Thus, a sum of the thickness of the light blocking layer  20  and the thickness of the color ink  40  sprayed onto the light blocking layer  20  is about 2.5 micrometers which is shallower than a sum of the thickness of the light blocking layer  20  and the thickness of the color ink  40  sprayed onto the exposed substrate  10 . This is because the color ink  40  sprayed onto the light blocking layer  20  has flowed to the openings  30  adjacent thereto.  
         [0043]     The channels  60  formed on the light blocking layer  20  have a concave shape so the color ink  40  sprayed onto the light blocking layer  20  may flow to the openings  30  adjacent thereto.  
         [0044]     Referring to  FIG. 4D , when the volatile solvent of the color ink  40  is volatilized under a predetermined temperature after the color ink  40  is sprayed, the red, green and blue color layers  50   r ,  50   g  and  50   b  may be formed on the substrate  10 . The color ink  40  sprayed onto the exposed substrate  10  through the openings  30  may evaporate at the same rate regardless of the region exposed by the substrate  10  through the openings  30 , so that the red, green and blue color layers  50   r ,  50   g  and  50   b  may each have uniform thicknesses.  
         [0045]      FIGS. 5A  to  5 D are cross-sectional views illustrating a method of fabricating the color filter substrate shown in  FIG. 2  according to an exemplary embodiment of the present invention. In  FIGS. 5A  to  5 D, the same reference numerals denote the same elements in  FIGS. 4A and 4D .  
         [0046]     Referring to  FIG. 5A , a layer  20 ′, which serves as the light blocking layer  20 , is formed on the substrate  10 . The substrate  10  may be a transparent glass substrate and the light blocking layer  20  may be a black-colored photoresist material. The layer  20 ′ for the light blocking layer  20  may be a positive type black-colored photoresist material.  
         [0047]     Referring to  5 B, the layer  20 ′ is exposed to a light passed through a slit mask  70  having a different transmittance in accordance with regions thereof. The slit mask  70  has various regions through which the light passes. The light either does not pass or partially passes, so that the openings  30  and the channels  60  may be formed using a single mask. The slit mask  70  has a first transmission region  71 , a second transmission region  72  and a non-transmission region  73 . The first and second transmission regions  71  and  72  correspond to the openings  30  and the channels  60 , respectively. The light substantially passes through the first transmission region  71  and partially passes through the second transmission region  72 , meaning that the intensity of the light passing through the second transmission region  72  is less than the intensity of the light passing through the first transmission region  71 . When the exposed layer  20 ′ using the slit mask  70  is developed, a portion of the layer  20 ′ corresponding to the first transmission region  71  is removed to form the openings  30  (refer to  FIG. 5C ) through the layer  20 ′. In addition, a portion of the layer  20 ′ corresponding to the second transmission region  72  is partially removed to form the channels  60  (refer to  FIG. 5C ), while the portion of the layer  20 ′ corresponding to the first transmission region  71 , and a portion of the layer  20 ′ corresponding to the non-transmission region  73  remain to form the light blocking layer  20  between the openings  30 . The channels  60  formed on the light blocking layer  20  may have various concave shapes such as a U-shape, a V-shape, etc., thereby allowing the second transmission region  72  to have various transmittances.  
         [0048]     Referring to  FIG. 5C , the color ink  40  is sprayed onto the substrate  10  exposed through the openings  30  formed through the light blocking layer  20  and onto the light blocking layer  20  on which the channels  60  are formed along the openings  30 . The color ink  40  sprayed onto the light blocking layer  20  on which the channel  60  is formed may partially flow to the openings  30  adjacent thereto, thereby uniformly distributing the color ink  40  onto the substrate  10  exposed through the openings  30 .  
         [0049]     The color ink  40  sprayed onto the substrate  10  exposed through the openings  30  is cured under a predetermined temperature to form the red color layer  50   r  as shown in  FIG. 5D . Although processes for the light blocking layer shown in  FIG. 5B  are different from those for the light blocking layer shown in  FIGS. 4A and 4B , the color filter substrate shown in  FIG. 5D  may have the same structure as the color filter substrate shown in  FIG. 4D .  
         [0050]      FIG. 6  illustrates a color filter substrate according to an exemplary embodiment of the present invention.  FIG. 7  is a cross-sectional view taken along line II-II′ of  FIG. 6 .  FIG. 8  is a cross-sectional view taken along line III-III′ of  FIG. 6 . In FIGS.  6  to  8 , the same reference numerals denote the same elements in  FIGS. 2A and 3B .  
         [0051]     Referring to FIGS.  6  to  8 , a color filter substrate  100  includes a substrate  10 , a light blocking layer  20  and a color layer  50 . The light blocking layer  20 , through which openings  30  are formed, is formed on the substrate  10  to partially expose the substrate  10 . The color layer  50  is formed on the exposed substrate  10  through the openings  30 .  
         [0052]     The color layer  50  may display various color layers, for example, a red color layer  50   r , a green color layer  50   g  and a blue color layer  50   b . The red, green and blue color layers  50   r ,  50   g  and  50   b  are alternately arranged with each other, and each of the red, green and blue color layers  50   r ,  50   g  and  50   b  is arranged in a line. The light blocking layer  20  is provided with channels  60  positioned between wells that makeup the same color layer of the red, green and blue color layers  50   r ,  50   g  and  50   b.    
         [0053]     The channels  60  are formed on the light blocking layer  20  such that the openings  30  that makeup the same color layer are connected to each other. The channels  60  may have a concave shape such as a U shape, a V shape, etc.  
         [0054]     When a red color ink is sprayed along a line where a corresponding color layer will be formed, the red color ink is sprayed onto the exposed substrate  10  through the openings  30  and onto the light blocking layer  20  on which the channels  60  are formed. The red color ink sprayed onto the light blocking layer  20  flows to adjacent openings  30  through the channels  60 , so that the red color ink sprayed onto the exposed substrate  10  may be formed to have a uniform thickness.  
         [0055]     Thus, when the red color ink sprayed onto the substrate  10  is cured, the volatile solvent of the red color ink is uniformly volatilized without regard to regions onto which the red color ink is sprayed. As a result, the red color layer  50   r  may be formed to have a uniform thickness as shown in  FIGS. 7 and 8 . The green and blue color layers  50   g  and  50   b  are formed by the same method as the red color layer  50   r , thereby uniformly forming the green and blue color layers  50   g  and  50   b.    
         [0056]      FIGS. 9A and 9B ,  10 A and  10 B,  11 A and  11 B and  12 A and  12 B are cross-sectional views illustrating a method of fabricating the color filter substrate of  FIG. 6  according to an exemplary embodiment of the invention.  
         [0057]     Referring to  FIGS. 9A and 9B , the light blocking layer  20  through which the openings  30  are formed, is formed on the substrate  10 .  
         [0058]     As shown in  FIGS. 10A and 10B , the light blocking layer  20  is patterned to form the channels  60  that are positioned between the openings  30  and to connect the adjacent openings  30 . Although not shown in  FIGS. 10A and 10B , the openings  30  and the channels  60  may be formed together by a photolithography process using a slit mask.  
         [0059]     Referring to  FIGS. 11A and 11B , the red color ink is sprayed onto the exposed substrate  10  through the openings  30  and onto the light blocking layer  20  on which the channels  60  are formed. The color ink may be sprayed in order of red, green and blue color inks.  
         [0060]     Referring to  FIGS. 12A and 12B , the red color ink sprayed onto the substrate  10  and the light blocking layer  20  is cured to form the red color layer  50   r . The red color ink sprayed onto the exposed substrate  10  flows to the adjacent openings  30  through the channels  60  while the red color ink is cured under a predetermined temperature, thereby uniformly forming the red color layer  50   r  as shown in  FIG. 12B . The green and blue color layers  50   g  and  50   b  are formed by the same method as the red color layer  50   r , thereby uniformly forming the green and blue color layers  50   g  and  50   b.    
         [0061]     Although the exemplary embodiments of the present invention have been described, it is understood that the present invention should not be limited to these exemplary embodiments but various changes and modifications can be made by one ordinary skilled in the art within the spirit and scope of the present invention as hereinafter claimed.