Patent Publication Number: US-2016238871-A1

Title: Array substrate and liquid crystal display panel using same

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the field of flat panel displaying, and in particular to an array substrate and a liquid crystal display panel using the array substrate. 
     2. The Related Arts 
     Liquid crystal displays (LCDs) have a variety of advantages, such as thin device body, low power consumption, and being free of radiation, and are thus of wide applications, such as mobile phones, personal digital assistants (PDAs), digital cameras, computer monitors, and notebook computer screens. 
     Most of the liquid crystal displays that are currently available in the market are backlighting liquid crystal displays, which comprise an enclosure, a liquid crystal display panel arranged in the enclosure, and a backlight module mounted in the enclosure. The structure of a conventional liquid crystal display panel is composed of a color filter (CF) substrate, a thin-film transistor (TFT) array substrate, and a liquid crystal layer arranged between the two substrates and the principle of operation is that a driving voltage is applied to the two glass substrates to control rotation of the liquid crystal molecules of the liquid crystal layer in order to refract out light emitting from the backlight module for generating images. Since the liquid crystal display panel itself does not emit light, light must be provided from the backlight module in order to normally display images. Thus, the backlight module is one of the key components of the liquid crystal displays. The backlight modules can be classified in two types, namely a side-edge backlight module and a direct backlight module, according to the site where light gets incident. The direct backlight module comprises a light source, such as a cold cathode fluorescent lamp (CCFL) or a light-emitting diode (LED), which is arranged at the backside of the liquid crystal display panel to form a planar light source directly supplied to the liquid crystal display panel. The side-edge backlight module comprises an LED light bar, serving as a backlight source, which is arranged at an edge of a backplane to be located rearward of one side of the liquid crystal display panel. The LED light bar emits light that enters a light guide plate (LGP) through a light incident face at one side of the light guide plate and is projected out of a light emergence face of the light guide plate, after being reflected and diffused, to pass through an optic film assembly so as to form a planar light source for the liquid crystal display panel. 
     Referring to  FIG. 1 , a schematic view is given to show the structure of a conventional liquid crystal display panel, which comprises an array substrate  100 , a color filter (CF) substrate  300  laminated to the array substrate  100 , and a liquid crystal (LC) layer  500  arranged between the array substrate  100  and the color filter substrate  300 , wherein the color filter substrate  300  comprises a pixel structure formed thereon to realize color displaying. 
     With the progress of technology, what is currently available in a liquid crystal display panel that combines a pixel structure with an array substrate and is referred to as COA (Color Filter On Array) technology. Based on such technology, a coplanar liquid crystal display panel (as shown in  FIG. 2 ) is available, which comprises: an array substrate  100 ′, a color filter substrate  300 ′ laminated to the array substrate  100 ′, and a liquid crystal layer  500 ′ arranged between the array substrate  100 ′ and the color filter substrate  300 ′, wherein the array substrate  100 ′ comprises a thin-film transistor (TFT) array and a pixel structure formed thereon. The thin-film transistor array comprises: a gate terminal  102 , a gate insulation layer  104  formed on the gate terminal  102 , source/drain terminals  106  formed on the gate insulation layer  104 , and an oxide semiconductor layer  108  formed on the source/drain terminals  106 . The oxide semiconductor layer  108  is generally formed of indium gallium zinc oxide (IGZO) and in the manufacturing process thereof, the source/drain terminals  106  must be formed first and forming the source/drain terminals  106  requires a second metal (M 2 ) layer be formed first and then subjected to etching. However, forming of the second metal layer readily causes damages to the surface of the gate insulation layer  104 , making the surface of the gate insulation layer  104  relatively roughened. When the oxide semiconductor layer  108  is then formed on the surface of the gate insulation layer  104 , poor property of the thin-film transistor may result. 
     Further, in such a liquid crystal display panel, the pixel structure of a pixel electrode  109  (as shown in  FIG. 3 ) is an entire solid surface structure. Such a structure leads to a relatively small aperture ratio of the liquid crystal display panel, thereby resulting in poor displaying performance of the liquid crystal display panel. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide an array substrate, which has a simple structure and excellent electrical property. 
     Another object of the present invention is to provide a liquid crystal display panel, which has a simple structure, a large aperture ratio, and excellent displaying performance. 
     To achieve the above objects, the present invention provides an array substrate, which comprises: a glass substrate, a gate terminal formed on the glass substrate, a gate insulation layer formed on the gate terminal and the glass substrate, source/drain terminals formed on the gate insulation layer, an oxide semiconductor layer formed on the source/drain terminals and the gate insulation layer, a protective layer formed on the oxide semiconductor layer, the source/drain terminals, and the gate insulation layer, a color filter formed on the protective layer, a planarization layer formed on the color filter and the protective layer, and a pixel electrode formed on the planarization layer. The pixel electrode is electrically connected to the source/drain terminals. The pixel electrode comprises an arrangement of lines that forms a radiating structure surrounding a center defined by a cross-shaped structure. 
     The gate insulation layer comprises a recess formed thereon to correspond to the oxide semiconductor layer and the oxide semiconductor layer covers the source/drain terminals and the recess. 
     The oxide semiconductor layer comprises an indium gallium zinc oxide layer. 
     The pixel electrode is formed of nano indium tin oxide. 
     The present invention also provides a liquid crystal display panel, which comprises: an array substrate, a color filter substrate laminated to the array substrate, and a liquid crystal layer arranged between the array substrate and the color filter substrate. The array substrate comprises: a glass substrate, a gate terminal formed on the glass substrate, a gate insulation layer formed on the gate terminal and the glass substrate, source/drain terminals formed on the gate insulation layer, an oxide semiconductor layer formed on the source/drain terminals and the gate insulation layer, a protective layer formed on the oxide semiconductor layer, the source/drain terminals, and the gate insulation layer, a color filter formed on the protective layer, a planarization layer formed on the color filter and the protective layer, and a pixel electrode formed on the planarization layer. The pixel electrode is electrically connected to the source/drain terminals. The pixel electrode comprises an arrangement of lines that forms a radiating structure surrounding a center defined by a cross-shaped structure. 
     The gate insulation layer comprises a recess formed thereon to correspond to the oxide semiconductor layer and the oxide semiconductor layer covers the source/drain terminals and the recess. 
     The oxide semiconductor layer comprises an indium gallium zinc oxide layer and the pixel electrode is formed of nano indium tin oxide. 
     The liquid crystal display panel further comprises a black matrix and a spacer arranged between the array substrate and the color filter substrate. 
     The black matrix and the spacer are formed on the color filter substrate. 
     The black matrix and the spacer are formed on the array substrate. 
     The present invention further provides a liquid crystal display panel, which comprises: an array substrate, a color filter substrate laminated to the array substrate, and a liquid crystal layer arranged between the array substrate and the color filter substrate, the array substrate comprising: a glass substrate, a gate terminal formed on the glass substrate, a gate insulation layer formed on the gate terminal and the glass substrate, source/drain terminals formed on the gate insulation layer, an oxide semiconductor layer formed on the source/drain terminals and the gate insulation layer, a protective layer formed on the oxide semiconductor layer, the source/drain terminals, and the gate insulation layer, a color filter formed on the protective layer, a planarization layer formed on the color filter and the protective layer, and a pixel electrode formed on the planarization layer, the pixel electrode being electrically connected to the source/drain terminals, the pixel electrode comprising an arrangement of lines that forms a radiating structure surrounding a center defined by a cross-shaped structure; 
     wherein the gate insulation layer comprises a recess formed thereon to correspond to the oxide semiconductor layer and the oxide semiconductor layer covers the source/drain terminals and the recess. 
     The oxide semiconductor layer comprises an indium gallium zinc oxide layer and the pixel electrode is formed of nano indium tin oxide. 
     The liquid crystal display panel further comprises a black matrix and a spacer arranged between the array substrate and the color filter substrate. 
     The black matrix and the spacer are formed on the color filter substrate. 
     The black matrix and the spacer are formed on the array substrate. 
     The efficacy of the present invention is that the present invention provides an array substrate and a liquid crystal display panel using the array substrate, in which a color filter is arranged on the array substrate and a pixel electrode is provided in an arrangement of lines that forms a radiating structure surrounding a center defined by a cross-shaped structure so as to effectively increase the aperture ratio and enhance the displaying performance. Further, a recess is formed in the gate insulation layer to provide an excellent contact surface between an oxide semiconductor layer and a gate insulation layer so as to effectively improve electrical property and enhance the quality of the liquid crystal display panel. 
     For better understanding of the features and technical contents of the present invention, reference will be made to the following detailed description of the present invention and the attached drawings. However, the drawings are provided for the purposes of reference and illustration and are not intended to impose limitations to the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The technical solution, as well as other beneficial advantages, of the present invention will be apparent from the following detailed description of embodiments of the present invention, with reference to the attached drawing. In the drawing: 
         FIG. 1  is a cross-sectional view showing the structure of a conventional liquid crystal display panel; 
         FIG. 2  is a schematic view showing a conventional liquid crystal display panel having a COA (Color Filter On Array) structure; 
         FIG. 3  is a schematic view showing a pixel structure of the liquid crystal display panel of  FIG. 2 ; 
         FIG. 4  is a schematic view showing the structure of an array substrate according to the present invention; 
         FIG. 5  is a schematic view showing a pixel structure of the array substrate according to the present invention; and 
         FIG. 6  is a schematic view showing the structure of a liquid crystal display panel according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     To further expound the technical solution adopted in the present invention and the advantages thereof, a detailed description is given to a preferred embodiment of the present invention and the attached drawings. 
     Referring to  FIGS. 4 and 5 , the present invention provides an array substrate, which comprises: a glass substrate  20 , a gate terminal  22  formed on the glass substrate  20 , a gate insulation layer  23  formed on the gate terminal  22  and the glass substrate  20 , source/drain terminals  24  formed on the gate insulation layer  23 , an oxide semiconductor layer  25  formed on the source/drain terminals  24  and the gate insulation layer  23 , a protective layer  26  formed on the oxide semiconductor layer  25 , the source/drain terminals  24 , and the gate insulation layer  23 , a color filter  27  formed on the protective layer  26 , a planarization layer  28  formed on the color filter  27  and the protective layer  26 , and a pixel electrode  29  formed on the planarization layer  28 . The pixel electrode  29  is electrically connected to the source/drain terminals  24  and the pixel electrode  29  comprises an arrangement of lines that forms a radiating structure surrounding a center defined by a cross-shaped structure. By forming the color filter  27  on the array substrate and providing the pixel electrode  29  in an arrangement of lines that forms a radiating structure surrounding a center defined by a cross-shaped structure, the aperture ratio is effectively increased and the displaying performance is enhanced. 
     The gate terminal  22 , the gate insulation layer  23 , the oxide semiconductor layer  25 , and the source/drain terminals  24  collectively constitute a thin-film transistor for realizing control of driving. The color filter  27  functions to realize color displaying. 
     Further, the gate insulation layer  23  comprises a recess  232  formed thereon to correspond to the oxide semiconductor layer  25 , and the oxide semiconductor layer  25  covers both the source/drain terminals  24  and the recess  232 . A specific manufacture operation is that in performing etching on a second metal layer to form the source/drain terminals  24 , a portion of the gate insulation layer  23  that corresponds to the oxide semiconductor layer  25  (namely the portion between the source/drain terminals  24 ) is subjected to further etching to form the recess  232  in order to remove a damaged portion of the gate insulation layer  23  resulting from bombardment by the second metal layer, thereby providing an excellent contact surface between the oxide semiconductor layer  25  and the gate insulation layer  23  and thus effectively improving electrical property and enhancing the quality of the array substrate. 
     In the instant embodiment, the oxide semiconductor layer  25  is an indium gallium zinc oxide (IGZO) layer. The pixel electrode  29  is formed of nano indium tin oxide (ITO). 
     Referring to  FIGS. 6 , as well as  FIGS. 4 and 5 , the present invention further provides a liquid crystal display panel, which comprises: an array substrate  40 , a color filter substrate  60  laminated to the array substrate  40 , and a liquid crystal layer  80  arranged between the array substrate  40  and the color filter substrate  60 . The array substrate  40  comprises: a glass substrate  20 , a gate terminal  22  formed on the glass substrate  20 , a gate insulation layer  23  formed on the gate terminal  22  and the glass substrate  20 , source/drain terminals  24  formed on the gate insulation layer  23 , an oxide semiconductor layer  25  formed on the source/drain terminals  24  and the gate insulation layer  23 , a protective layer  26  formed on the oxide semiconductor layer  25 , the source/drain terminals  24 , and the gate insulation layer  23 , a color filter  27  formed on the protective layer  26 , a planarization layer  28  formed on the color filter  27  and the protective layer  26 , and a pixel electrode  29  formed on the planarization layer  28 . The pixel electrode  29  is electrically connected to the source/drain terminals  24  and the pixel electrode  29  comprises an arrangement of lines that forms a radiating structure surrounding a center defined by a cross-shaped structure. By forming the color filter  27  on the array substrate and providing the pixel electrode  29  in an arrangement of lines that forms a radiating structure surrounding a center defined by a cross-shaped structure, the aperture ratio is effectively increased and the displaying performance is enhanced. 
     The gate terminal  22 , the gate insulation layer  23 , the oxide semiconductor layer  25 , and the source/drain terminals  24  collectively constitute a thin-film transistor, which drives liquid crystal molecules contained in the liquid crystal layer  80  to rotate so as to realize selection of light and thus achieve displaying. The color filter  27  functions to realize color displaying. 
     Further, the gate insulation layer  23  comprises a recess  232  formed thereon to correspond to the oxide semiconductor layer  25 , whereby the oxide semiconductor layer  25  covers both the source/drain terminals  24  and the recess  232 . A specific manufacture operation is that in performing etching on a second metal layer to form the source/drain terminals  24 , a portion of the gate insulation layer  23  that corresponds to the oxide semiconductor layer  25  (namely the portion between the source/drain terminals  24 ) is subjected to further etching to form the recess  232  in order to remove a damaged portion of the gate insulation layer  23  resulting from bombardment by the second metal layer, thereby providing an excellent contact surface between the oxide semiconductor layer  25  and the gate insulation layer  23  and thus effectively improving electrical property and enhancing the quality of the array substrate. 
     The oxide semiconductor layer  25  is an indium gallium zinc oxide layer. The pixel electrode  29  is formed of nano indium tin oxide. 
     It is noted that the liquid crystal display panel of the present invention further comprises a black matrix  50  and a spacer  70  arranged between the array substrate  40  and the color filter substrate  60 . The black matrix  50  and the spacer  70  are formed on the color filter substrate  60  or the array substrate  40 . In the instant embodiment, the black matrix  50  and the spacer  70  are formed on the color filter substrate  60  and are located under a common electrode  72  that is formed on the color filter substrate  60 . 
     In summary, the present invention provides an array substrate and a liquid crystal display panel using the array substrate, in which a color filter is arranged on the array substrate and a pixel electrode is provided in an arrangement of lines that forms a radiating structure surrounding a center defined by a cross-shaped structure so as to effectively increase the aperture ratio and enhance the displaying performance. Further, a recess is formed in the gate insulation layer to provide an excellent contact surface between an oxide semiconductor layer and a gate insulation layer so as to effectively improve electrical property and enhance the quality of the liquid crystal display panel. 
     Based on the description given above, those having ordinary skills of the art may easily contemplate various changes and modifications of the technical solution and technical ideas of the present invention and all these changes and modifications are considered within the protection scope of right for the present invention.