Abstract:
A reflective-type liquid crystal display device includes first and second substrates, a liquid crystal layer between the first and second substrates, thin film transistors on each cross of gate and data bus lines, a photoresist layer on the gate and data bus lines, and thin film transistors, reflection electrodes on the photoresist layer and electrically coupled to the thin film transistors, and light shield layers on the gate and data bus lines.

Description:
BACKGROUND OP THE INVENTION  
         [0001]    A. Field of the Invention  
           [0002]    This invention relates to a liquid crystal display device and, more particularly, a reflective-type liquid crystal display device and a method of manufacturing thereof.  
           [0003]    B. Description of the Related Art  
           [0004]    The liquid crystal display device (hereinafter “LCD”) can be classified into a transmissive-type LCD using a back light and a reflective-type LCD using a surrounding light in accordance with the driving type. The transmissive-type LCD, however, requires a high consumption power. Further, it is difficult to minimize the apparatus due to the back light.  
           [0005]    For the above reason, recently, the reflective-type LCD have been extensively studied.  
           [0006]    Since a matter of concern of the reflective-type LCD is to use the surrounding light effectively, at present, a reflective-type LCD having a light compensation film which is provided inner side and/or outer side of the apparatus or a modified structure of reflector being proposed.  
           [0007]    The U.S. Pat. No. 5,500,750 have proposed a reflector having convex portions. The above patent disclosed a structure comprising a pair of substrates having a liquid crystal layer therebetween, a plurality of bumps on the lower substrate, an insulating layer on the bumps, and a plurality of reflection electrodes on the insulating layer and thin film transistors (hereinafter “TFT”). In this structure, the reflection electrode which functions as a black matrix on the TFT is electrically insulated from other electrodes, and a plurality of black filters shield open regions between neighboring reflection electrodes.  
           [0008]    The above LCD, however, have manufactured by complex processes, and have not proposed to use the surrounding light effectively. Namely, since the black filter is disposed in the direction which light is incident, an incidence area of light is limited and a light leakage may be generated on the opened regions between neighboring reflection electrodes.  
         SUMMARY OF THE INVENTION  
         [0009]    In view of the foregoing, it is an object of the present invention to provide a reflective-type LCD having a superior efficiency and to provide a method of manufacturing thereof.  
           [0010]    The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.  
           [0011]    To achieve the object and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention includes first and second substrates, a liquid crystal layer between the first and second substrates, a photoresist layer on the first substrate, a plurality of reflection electrodes on the photoresist layer, a plurality of black matrixes on open regions between neighboring reflection electrodes, a first alignment layer over the first substrate, a counter electrode on the second substrate, and a second alignment layer over the second substrate.  
           [0012]    According to another aspect of the invention, the reflection electrodes are opened at TFT regions as well as between neighboring reflection electrodes.  
           [0013]    A method according to the invention includes the steps of providing first and second substrates, forming a plurality of TFTs on the first substrate, forming a photoresist layer over the first substrate, forming a plurality of black matrixes on the photoresist layer, forming a plurality of reflection electrodes on the photoresist layer and the black matrixes, providing first and second alignment layers on the first and second substrates, and providing a liquid crystal layer between the first and second substrates.  
           [0014]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. 
       
    
    
       [0015]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate the embodiments of the invention and, together with the description, serve to explain the principles of the invention.  
       BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    [0016]FIG. 1A is a plan view of an LCD in accordance with a first embodiment of the present invention, and FIG. 1B is a section view in accordance with A-A line of FIG. 1A.  
         [0017]    [0017]FIG. 2A is a plan view of an LCD in accordance with a second embodiment of the present invention, and FIG. 2B is a section view in accordance with A-A line of FIG. 2A.  
         [0018]    [0018]FIG. 3 is a section view in accordance with B-B line of FIG. 1A and FIG. 2A. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]    Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.  
         [0020]    [0020]FIG. 1A is a plan view of an LCD in accordance with a first embodiment of the present invention, and FIG. 1B is a section view in accordance with A-A line of FIG. 1A.  
         [0021]    As shown in the drawings, an unit pixel in accordance with the present invention is represented by, a gate bus line  11 , a data bus line  20 , and a gate electrode  12  on a first substrate  10   a , a gate insulator  14  on the first substrate  10   a , a semiconductor layer  16 , an ohmic contact layer  18 , a source electrode  19   a , and a drain electrode  19   b  on the gate insulator  14 , a photoresist layer  22  over the first substrate  10   a , a black matrix  24  on the photoresist layer  22 , a reflection electrode  26  on the photoresist layer  22 , a first alignment layer  30   a  on the reflection electrode  26 , a counter electrode  29  on a second substrate  10   b , and a second alignment layer  30   b  on the counter electrode  29 .  
         [0022]    A method for manufacturing the LCD having above-mentioned structure is described in detail hereinafter.  
         [0023]    The gate electrode  12  is formed by depositing and patterning a metal such as Ta, Cr, or Al by the sputtering method on the first substrate  10   a , at this time the gate bus line  11  is formed. The gate insulator  14  is formed by depositing an inorganic material such as SiNx or SiOx by the PECVD(plasma enhanced chemical vapor deposition) method on the gate insulator  14  and the first substrate  10   a . The semiconductor layer  16  and the ohmic contact layer  18  are formed by depositing and patterning materials such as a-Si:H and n + a-Si:H by PECVD method. After, the source electrode  19   a , the drain electrode  19   b , and the data bus line  20  are formed by depositing a metal such as Ti, Cr/Al, Cr/Al-Ta, or Cr/Al/Al-Ta by sputtering method.  
         [0024]    To form the photoresist layer  22  on the TFT and the gate and data bus lines  11 ,  20  includes the steps of depositing a photopolymer resin such as acrylic resin over the first substrate  10   a , exposing the photopolymer resin to light such as ultraviolet light with a mask(not shown) having a plurality of micro patterns, partially developing the photopolymer resin exposed to light whereby a surface of the photopolymer resin being continually bent. In that processes, two regions to be developed or undeveloped are determined by the micro patterns of the mask. Further, a size of the region to be developed is 0.1-0.5 d  preferably wherein the d is thickness of the photoresist layer  22  and it&#39;s size is in 1-5 micrometer. A bent shape of the surface is determined by exposing time of light and/or developing time.  
         [0025]    The reflection electrode  26  is formed by depositing a metal such as Al or Ag by evaporation or sputtering methods on the photoresist layer  22 , at this time, the reflection electrode  26  is electrically coupled to the drain electrode  19   b  through a contact hole  28 . Further, the neighboring reflection electrodes on the gate and data bus lines  11 ,  20  are electrically insulated from each other.  
         [0026]    A mark  24  in the drawing represents a black matrix, the black matrix  24  is formed by depositing a material such as a black resin at an open region on the gate and data bus lines  11 ,  20 .  
         [0027]    The first and second alignment layer  30   a ,  30   b  are formed by rubbing method using polyimide, polyamide, polyvinylalcohol, polyamic acid, or Sio 2  and/or photo-alignment method using a photo-alignment material such as polysiloxanecinnamate, polyvinylcinnamate, or celluosecinnamate. Further in case the photo-alignment method, it is possible to expose UV light to at least one surface of the substrates using non-polarized light or partially polarized light.  
         [0028]    The counter electrode  29  is formed by depositing a transparent metal such as ITO(indium tin oxide) by sputtering method.  
         [0029]    [0029]FIG. 2A is a plan view of an LCD in accordance with a second embodiment of the present invention, and FIG. 2B is a section view in accordance with A-A line of FIG. 2A.  
         [0030]    The second embodiment of the present invention proceeds in the same manner as for the first embodiment except that the reflection electrode  26  on the TFT is removed and the black matrix  24  is extended onto a removed region of the reflection electrode so as to prevent from an abnormal electric field which may be generated on the TFT.  
         [0031]    [0031]FIG. 3 is a section view in accordance with B-B line of FIG. 1A and FIG. 2A, as shown in the drawing, some parts of the data bus line  20  on the gate insulator  14  covered by the neighboring reflection electrodes, the black matrix  24  is formed on the open region between the neighboring reflection electrodes. By this structure, light leakage on the open region is prevented.  
         [0032]    According to the present invention, it is possible to achieve a reflective-type LCD having a superior efficiency because the black matrix is on the phoresist layer.  
         [0033]    Further, it is possible to manufacture the reflective-type LCD with simple processes.  
         [0034]    Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein.  
         [0035]    It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims and their equivalents.