Patent Publication Number: US-11650461-B2

Title: Display substrate and manufacturing method thereof and display apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. Ser. No. 16/650,092 filed on Mar. 24, 2020 which is a national stage application of international application PCT/CN2019/105512 filed on Sep. 12, 2019, which claims priority to Chinese Patent Application No. 201811441329.6 filed Nov. 29, 2018, the disclosures of which are incorporated herein by reference in their entirety for all purposes. 
    
    
     TECHNICAL FIELD 
     Embodiments of the present disclosure relate to a display substrate and a manufacturing method thereof and a display apparatus. 
     BACKGROUND 
     In the field of display, an array substrate of a display panel is provided with a plurality of insulation layers and a plurality of conductive layers separated by the plurality of insulation layers. For example, the plurality of insulation layers include an inorganic insulation layer and an organic insulation layer, and the organic insulation layer may be made thicker than the inorganic insulation layer, so that the organic insulation layer can be used for reducing storage capacitance and reducing a load and power consumption. 
     SUMMARY 
     Embodiments of the present disclosure provide a display substrate and a manufacturing method thereof and a display apparatus. The display substrate has a good water vapor blocking ability. 
     At least one embodiment of the disclosure provides a display substrate, comprising: a base substrate; a sealant on the base substrate; and a contact layer between the base substrate and the sealant, the contact layer being in contact with the sealant, a contact layer surface of the contact layer away from the base substrate is non-flat at a contact position where the contact layer is in contact with the sealant. 
     For example, the contact layer surface comprises at least one contact layer groove at the contact position where the contact layer is in contact with the sealant, and the sealant extends into the at least one contact layer groove. 
     For example, the at least one contact layer groove comprises a first groove and a second groove, and the first groove and the second groove are different in depth. 
     For example, the first groove is plural and the second groove is plural, and a plurality of first grooves and a plurality of second grooves are staggered. 
     For example, the at least one contact layer groove comprises a closed loop-shaped groove. 
     For example, the display substrate further comprises an organic layer between the base substrate and the contact layer, wherein an organic layer surface of the organic layer being away from the base substrate is non-flat at a position the sealant, so that the contact layer surface is non-flat at the contact position. 
     For example, the organic layer surface has at least one organic layer groove at the position of the sealant, and both the contact layer and the sealant extend into the at least one organic layer groove. 
     For example, the at least one organic layer groove comprises at least one via-hole typed groove and at least one blind-hole typed groove, a depth of the via-hole typed groove is equal to a thickness of the organic layer, and a depth of the blind-hole typed groove is smaller than the thickness of the organic layer. 
     For example, the at least one organic layer groove comprises a plurality of via-hole typed grooves, and a depth of each via-hole typed groove is equal to a thickness of the organic layer. 
     For example, the display substrate further comprises: a first inorganic layer on the base substrate; and a second inorganic layer on a side of the first inorganic layer away from the base substrate, wherein orthographic projections of the first inorganic layer and the second inorganic layer on the base substrate both overlap with an orthographic projection of the sealant on the base substrate, and the second inorganic layer is used as the contact layer. 
     For example, the display substrate further comprises: a first inorganic layer on the base substrate; and a second inorganic layer on a side of the first inorganic layer away from the base substrate, wherein both the first inorganic layer and the second inorganic layer are between the contact layer and the base substrate. 
     For example, the display substrate further comprises: a first metal layer, a semiconductor layer, a second metal layer and an electrode layer, wherein the first inorganic layer is between the first metal layer and the semiconductor layer, the second inorganic layer is between the semiconductor layer and the second metal layer, and both the organic layer and the contact layer are between the second metal layer and the electrode layer. 
     For example, materials of the first inorganic layer and the second inorganic layer are same in chemical composition, and a refractive index of the first inorganic layer is greater than a refractive index of the second inorganic layer so as to increase stripping resistance of the sealant. 
     For example, the materials of the first inorganic layer and the second inorganic layer are same as each other, and the material is selected from the group consisting of silicon dioxide, silicon nitride, and silicon oxynitride and combination thereof. 
     For example, the sealant is a light curable type sealant. 
     At least one embodiment of the disclosure provides a display apparatus, which comprises the display substrate in above-mentioned embodiments. 
     At least one embodiment of the disclosure provides a manufacturing method of a display substrate, comprising: forming a contact layer on the base substrate; and forming a sealant on the contact layer, the sealant being in contact with the contact layer, a contact layer surface of the contact layer away from the base substrate is non-flat at a contact position where the contact layer is in contact with the sealant. 
     For example, sequentially forming a first inorganic material layer and a second inorganic material layer on the base substrate; and performing patterning processing on the first inorganic material layer and the second inorganic material layer during same mask process, so as to respectively form a first inorganic layer and a second inorganic layer, wherein the second inorganic layer is used as the contact layer; and in a dry etching process of the same mask process, a dry etching rate of the first inorganic material layer is smaller than a dry etching rate of the second inorganic material layer. 
     For example, sequentially forming a first inorganic material layer, a second inorganic material layer and a contact-layer material layer on the base substrate; and performing patterning processing on the first inorganic material layer the second inorganic material layer and the contact-layer material layer during same mask process, so as to respectively form a first inorganic layer, a second inorganic layer and the contact layer, wherein in a dry etching process of the same mask process, dry etching rates of the first inorganic material layer, the second inorganic material layer and the contact-layer material layer are sequentially increased. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to clearly illustrate the technical solution of the embodiments of the disclosure, the drawings of the embodiments will be briefly described in the following; it is obvious that the described drawings are only related to some embodiments of the disclosure and thus are not limitative of the disclosure. 
         FIG.  1 A  is a partially cross-sectional schematic diagram of a display panel according to an embodiment of the present disclosure; 
         FIG.  1 B  is a partially schematic diagram of a display substrate as shown in  FIG.  1 A ; 
         FIG.  1 C  is a top-view schematic diagram of a partial structure in the display substrate as shown in  FIG.  1 A ; 
         FIG.  2 A  is a partially cross-sectional schematic diagram of a display panel according to another embodiment of the present disclosure; 
         FIG.  2 B  is a partially schematic diagram of a display substrate as shown in  FIG.  2 A ; 
         FIG.  2 C  is a schematic diagram of the display substrate as shown in  FIG.  2 A  blocking water vapor; 
         FIG.  2 D  is a cross-sectional schematic diagram of a display substrate including two through-hole grooves according to yet another embodiment of the present disclosure; 
         FIG.  2 E  is a top-view schematic diagram of two through-hole grooves as shown in  FIG.  2 D ; 
         FIG.  3    is a partially sectional schematic diagram of a display panel according to still another embodiment of the present disclosure; 
         FIG.  4    is a schematic diagram of a display substrate having via holes disposed in a plurality of inorganic layers according to an embodiment of the present disclosure; 
         FIG.  5    is a light-transmittance graph showing a plurality of inorganic layers in a display substrate having different refractive indices according to an embodiment of the present disclosure; 
         FIG.  6    is a partially cross-sectional schematic diagram of a display panel according to another embodiment of the present disclosure; 
         FIG.  7    is a schematic diagram of forming an organic material layer on a base substrate in a manufacturing method of a display substrate according to an embodiment of the present disclosure; 
         FIG.  8 A  and  FIG.  8 B  are schematic diagrams of forming a first inorganic layer, a second inorganic layer and a contact layer in a manufacturing method of a display substrate according to an embodiment of the present disclosure; and 
         FIG.  9    is a schematic diagram of forming a first inorganic material layer and a second inorganic material layer on a base substrate in a manufacturing method of a display substrate according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In order to make objects, technical details and advantages of the embodiments of the disclosure apparent, the technical solutions of the embodiments will be described in a clearly and fully understandable way in connection with the drawings related to the embodiments of the disclosure. Apparently, the described embodiments are just a part but not all of the embodiments of the disclosure. Based on the described embodiments herein, those skilled in the art can obtain other embodiment(s), without any inventive work, which should be within the scope of the disclosure. 
     Unless otherwise defined, all the technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. The terms “first,” “second,” etc., which are used in the description and the claims of the present disclosure, are not intended to indicate any sequence, amount or importance, but distinguish various components. The terms “comprises,” “comprising,” “includes,” “including,” etc., are intended to specify that the elements or the objects stated before these terms encompass the elements or the objects and equivalents thereof listed after these terms, but do not preclude the other elements or objects. The phrases “connect”, “connected”, etc., are not intended to define a physical connection or mechanical connection, but may include an electrical connection, directly or indirectly. “On,” “under,” “right,” “left” and the like are only used to indicate relative position relationship, and when the position of the object which is described is changed, the relative position relationship may be changed accordingly. 
     In a display panel, due to arrangement of an organic insulation layer, paths for water vapor to enter the interior of the display panel are elongated, resulting in that reliability of a high-temperature high-humidity experiment of the display panel is reduced. 
     At least one embodiment of the present disclosure provides a display substrate and a manufacturing method thereof and a display apparatus. In the display substrate, a film layer (referred to “contact layer” hereafter) in contact with a sealant has a non-flat surface at a position where the film layer is in contact with the sealant, so that a position of the sealant, which is in contact with the non-flat surface, is also not flat, and thus, a path for water vapor molecules to enter a sealed region of the display panel from an interface between the sealant and the contact layer can be prolonged, thereby benefiting for increasing a water vapor blocking ability of the display panel and increasing high-temperature high-humidity reliability of the product. 
     The display substrate and the manufacturing method thereof and the display apparatus which are provided by the embodiments of the present disclosure will be illustrated in detail below in connection with the drawings. 
     At least one embodiment of the present disclosure provides a display substrate. As shown in  FIG.  1 A  and  FIG.  1 B , the display substrate includes a base substrate  100 A and a sealant  300  positioned on the base substrate  100 A, the display substrate further includes a contact layer  50  which is positioned between the base substrate  100 A and the sealant  300  and is in contact with the sealant  300 , and a contact layer surface  50 A (an upper surface of the contact layer  50  as shown in the drawings) of the contact layer  50 , which is away from the base substrate  100 A, is not flat at a contact position where the contact layer  50  is in contact with the sealant  300 , so that the sealant  300  is also not flat at the contact position. It should be noted that  FIG.  1 A  and  FIG.  1 B  only show part of components in the display substrate, and for example, structures such as a conductive layer, a semiconductor layer or an insulation layer and the like, which are not shown in the drawings, are also arranged between the contact layer  50  and the base substrate  100 A. 
     For example, the base substrate  100 A is a transparent substrate, such as a glass substrate, a quartz substrate or a plastic substrate and the like. 
     For example, the sealant  300  is organic glue, e.g., light curable glue (for example, ultraviolet light curable glue) or thermally curable glue and the like. 
     For example, the contact layer  50  is a transparent material layer such as an inorganic layer or an organic layer, and for example, the inorganic layer is an inorganic insulation layer, and the organic layer is an organic insulation layer. 
     For example, as shown in  FIG.  1 A  and  FIG.  1 B , a display panel includes a first substrate  100  and a second substrate  200  which are arranged face to face, the sealant  300  connects the first substrate  100  with the second substrate  200 , and the first substrate  100  includes the base substrate  100 A. For example, the display panel is a liquid crystal panel, and in this case, a sealed cavity formed by the first substrate  100 , the second substrate  200  and the sealant  300  is filled with a liquid crystal material so as to form a liquid crystal cell, and a spacer PS is arranged between the first substrate  100  and the second substrate  200  so as to keep a cell gap of liquid crystals. It should be noted that embodiments of the display panel include, but are not limited to, the liquid crystal panel. 
     For example, the first substrate  100  is an array substrate, the array substrate is provided with switching elements (e.g., a transistor) arranged in an array and pixel electrodes respectively and electrically connected with the switching elements, and the first substrate  100  further includes an electrode layer  70  and an alignment layer  60  covering the electrode layer  70 . For example, the alignment layer  60  and the sealant  300  do not overlap with each other. For example, the electrode layer  70  is a pixel electrode layer including the pixel electrode, alternatively, the electrode layer  70  includes a strip-shaped pixel electrode and a strip-shaped common electrode which are alternately arranged; and in other embodiments, the first substrate  100  further includes another electrode layer overlapping with the electrode layer  70 , one of the another electrode layer and the electrode layer  70  is a pixel electrode layer including the pixel electrode, and the other one of the another electrode layer and the electrode layer  70  is a common electrode layer including the common electrode. 
     For example, the second substrate  200  includes the base substrate (e.g., the transparent substrate such as the glass substrate, the quartz substrate or the plastic substrate and the like), a black matrix BM positioned on the base substrate and an overcoat layer OC positioned between the black matrix BM and the sealant  300 . For example, the second substrate  200  is a color filter substrate including a color filter layer. 
     For example, in order to transfer a shape of a non-flat portion of the contact layer surface  50 A of the contact layer  50  to the sealant  300 , the contact layer  50  contacts the sealant  300  in such a mode that: the contact layer surface  50 A of the contact layer  50 , which is away from the base substrate  100 A, is provided with at least one contact layer groove at the contact position where the contact layer  50  is in contact with the sealant  300 , and the sealant  300  extends into the at least one contact layer groove. 
     For example, the at least one contact layer groove formed on the contact layer surface  50 A of the contact layer  50  includes different depths of grooves. For example, as shown in  FIG.  1 A  and  FIG.  1 B , the at least one contact layer grooves formed on the contact layer surface  50 A of the contact layer  50  includes a first groove  51  and a second groove  52 , and the first groove  51  and the second groove  52  have different depths. In a case that the contact layer  50  is formed of an organic insulation layer, an organic material in a bottom of the groove with a relatively small depth among the first groove  51  and the second groove  52  can absorb part of water molecules so as to further reduce the water molecules entering a sealed region; and similarly, in a case that the contact layer  50  is formed of an inorganic insulation layer and the contact layer  50  covers the organic insulation layer, the organic material in the bottom of the groove with the relatively small depth among the first groove  51  and the second groove  52  can absorb part of water molecules, so as to further reduce the water molecules entering the sealed region. 
     In other embodiments, for example, the at least one contact layer groove formed on the contact layer surface  50 A of the contact layer  50  is the same in depth. 
     For example, in order to further increase the water vapor blocking ability of the display panel, as shown in  FIG.  1 A  and  FIG.  1 B , the at least one contact layer groove formed on the contact layer surface  50 A of the contact layer  50  includes a plurality of first grooves  51  and a plurality of second grooves  52 . The plurality of first grooves  51  and the plurality of second grooves  52  are staggered, i.e., the second groove  52  is arranged between at least two adjacent first grooves  51 , and/or the first groove  51  is arranged between at least two adjacent second grooves  52 . For example, the plurality of first grooves  51  and the plurality of second grooves  52  are alternately and cyclically arranged, i.e., one second groove  52  is arranged between any two adjacent first grooves  51  and one first groove  51  is arranged between any two adjacent second grooves  52 . 
     For example, in order to further increase the water vapor blocking ability of the display panel, as shown in  FIG.  1 C , the at least one contact layer groove formed on the contact layer surface  50 A of the contact layer  50  includes a closed loop-shaped groove (with reference to a deep color loop shape in  FIG.  1 C ). For example, the at least one contact layer groove includes a plurality of closed loop-shaped grooves, and for example, both the first groove  51  and the second groove  52  are the closed loop-shaped grooves. It should be noted that a region surrounded by two dotted lines in  FIG.  1 C  is a region where the sealant  300  is positioned, a region surrounded by the region where the sealant  300  is positioned is the sealed region. For example, the aforementioned spacer PS, the alignment layer  60  and the electrode layer  70  are arranged in the sealed region. 
     For example, a non-flat organic layer is formed on the base substrate  100 A, and then the contact layer  50  covering the organic layer (for example, the contact layer  50  covers and is in direct contact with the organic layer) is formed, in this way, the contact layer surface  50 A of the contact layer  50  is not flat at the contact position where the contact layer  50  is in contact with the sealant  300 . In this case, for example, as shown in  FIG.  2 A  and  FIG.  2 B , a display substrate provided by at least one embodiment of the present disclosure further includes an organic layer  14  positioned between the base substrate  100 A and the contact layer  50 . An organic layer surface  14 A (with reference to an upper surface of the organic layer  14  in the drawings) of the organic layer  14 , which is away from the base substrate  100 A, is not flat at a position of the sealant  300 , that is, the organic layer surface  14 A of the organic layer  14  is provided with a non-flat portion overlapping with the sealant  300 , so that the contact layer surface  50 A of the contact layer  50  is not flat at the contact position. 
     It should be noted that  FIG.  2 A  and  FIG.  2 B  only show part of components in the display substrate, and for example, structures such as a conductive layer, a semiconductor layer or an insulation layer and the like, which are not shown in the drawings, are also arranged between the organic layer  14  and the base substrate  100 A. In addition, the arrangement mode of the contact layer  50  and the sealant  300  in  FIG.  2 A  and  FIG.  2 B  can refer to related description in the embodiment as shown in  FIG.  1 A  and  FIG.  1 B , and is not repeated herein. 
     In the embodiment of the present disclosure, even if both the contact layer  50  and the non-flat portion overlap with the sealant  300 , the mask plate for forming the contact layer  50  doesn&#39;t need to change, because the non-flat organic layer  14  is firstly formed and then the contact layer in direct contact with the organic layer  14  is formed, in this way, the non-flat portion of the contact layer  50  is formed. It only needs to avoid that the formed contact layer  50  fills and levels up the non-flat portion of the organic layer  14 . For example, as shown in  FIG.  2 A  and  FIG.  2 B , the contact layer  50  is not flat and is continuous at the position of the non-flat portion of the organic layer  14 . 
     For example, the organic layer surface  14 A of the organic layer  14 , which is away from the base substrate  100 A, is provided with at least one organic layer groove at the position of the sealant  300 , the contact layer  50  extends into the at least one organic layer groove, and the sealant  300  also extends into the at least one organic layer groove. In the embodiment of the present disclosure, the organic layer  14  can be made thicker, which enables the organic layer groove in the organic layer  14  to have a large depth, so that a portion of the sealant  300 , which extends into the organic layer groove, has a large length, thereby further benefiting for prolonging the path for the water molecules to enter the sealed region (the entrance path of the water molecules can refer to  FIG.  2 C ) to further increase the water vapor blocking ability of the display panel. 
     In order to avoid a case that an excessive opening width of the organic layer groove causes large influence on the water vapor blocking ability of the display panel, the opening width of the at least one organic layer groove in the organic layer  14  is, for example, smaller than or equal to 10 micrometers, i.e., a size of an orthographic projection of each organic layer groove on the base substrate  100 A is smaller than or equal to 10 micrometers. In consideration of accuracy of the mask for producing the organic layer  14 , for example, the opening width of each organic layer groove is greater than or equal to 6 micrometers and less than or equal to 10 micrometers. 
     For example, as shown in  FIG.  2 A  and  FIG.  2 B , the at least one organic layer groove disposed on the organic layer surface  14 A of the organic layer  14  and at the position of the sealant  300  includes at least one via-hole typed groove  141  and at least one blind-hole typed groove  142 , a depth of the via-hole typed groove  141  is equal to a thickness of the organic layer  14  so as to enable the via-hole typed groove  141  to penetrate the organic layer  14 , and a depth of the blind-hole typed groove  142  is smaller than the thickness of the organic layer  14 . A material of the organic layer at the position of the blind-hole typed groove  142  can absorb part of water molecules so as to further reduce the water molecule entering the sealed region. 
     For example, as shown in  FIG.  2 D , the organic layer groove includes a plurality of via-hole typed grooves  141  (in  FIG.  2 D , there are two via-hole typed grooves for example), and the depth of each via-hole typed groove  141  is equal to the thickness of the organic layer  14 . For example, as shown in  FIG.  2 E , each via-hole typed groove  141  is a closed loop-shaped groove. 
     For example, in any one of embodiments of the present disclosure, the organic layer  14  can be made from resin or a similar transparent insulation organic material so as to obtain a large thickness. 
     For example, as shown in  FIG.  3   , a display substrate provided by at least one embodiment of the present disclosure includes a first inorganic layer  11  positioned on the base substrate  100 A and a second inorganic layer  12  positioned on a side of the first inorganic layer  11 , which is away from the base substrate  100 A. Orthographic projections of the first inorganic layer  11  and the second inorganic layer  12  on the base substrate  100 A both overlap with an orthographic projection of the sealant  300  on the base substrate  100 A, and both orthographic projections of the first inorganic layer  11  and the second inorganic layer  12  on the base substrate  100 A are positioned between the contact layer  50  and the base substrate  100 A. Herein, the term “overlap” means that there is an overlap region between comparison objects, and thus, the comparison objects may completely coincide with each other, and also may partially coincide with each other. In this embodiment, each of the orthographic projections of the first inorganic layer  11  and the second inorganic layer  12  on the base substrate  100 A has an overlap region with the orthographic projection of the sealant  300  on the base substrate  100 A, and the non-flat surface of the contact layer  50  is formed in the overlap regions, so as to further increase the water vapor blocking ability of the display panel. It should be noted that the arrangement mode of the contact layer  50  and the sealant  300  in the embodiment as shown in  FIG.  3    can refer to related description in the embodiment as shown in  FIG.  1 A  and  FIG.  1 B , and the arrangement mode of the organic layer  14  in the embodiment as shown in  FIG.  3    can refer to related description in the embodiment as shown in  FIG.  2 A  and  FIG.  2 B , which are not repeated herein. 
     For example, the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50  are all inorganic insulation layers. For example, as shown in  FIG.  3   , a first metal layer  81 , a semiconductor layer  90 , a second metal layer  82  and an electrode layer  70  are sequentially arranged on the base substrate  100 A. The first inorganic layer  11  is positioned between the first metal layer  81  and the semiconductor layer  90 , the second inorganic layer  12  is positioned between the semiconductor layer  90  and the second metal layer  82 , and both the organic layer  14  and the contact layer  50  are positioned between the second metal layer  82  and the electrode layer  70 . 
     For example, the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50  can be formed by the same mask process (i.e., a patterning process achieved by using the same mask). For example, in the same mask process, a via hole  125  as shown in  FIG.  4   , which simultaneously penetrates the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50 , is formed by dry etching. The via hole  125  is used for implementing, for example, an electrical connection between a conductive structure which the electrode layer  70  includes and a conductive structure which the first metal layer  81  includes. 
     For example, for the same dry etching process (i.e., a dry etching step which the same mask process includes), dry etching rates of the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50  are sequentially increased (i.e., the smaller a distance to the base substrate  100 A is, the smaller the dry etching rate is); in other words, the layer further away from the base substrate  100 A is easier to etch. It is beneficial for enabling the via hole  125  simultaneously penetrating the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50  to have a good appearance, i.e., an opening size of the via hole  125  is gradually increased in a direction away from the base substrate, so as to ensure the electrical connection between different conductive structures at the position of the via hole  125 . 
     In study, an inventor of the present application founds that, in a case that materials of the plurality of inorganic layers which the display substrate includes adopt the same chemical composition, the higher refractive index of the inorganic layer is, the smaller the dry etching rate of the inorganic layer is. Based on this, the inventor of the present application notices that a good dry etching effect and a high light-transmittance can be simultaneously obtained while the materials of the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50  are same in their chemical compositions and the refractive indices of the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50  are sequentially reduced (i.e., the smaller the distance to the base substrate  100 A is, the higher the refractive index is). Namely, after dry-etching, a laminated structure of the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50  not only has a high light transmittance, but also makes the via hole  125  having the good appearance. In a case that the sealant  300  is the light curable type sealant, a good curable effect can be obtained so as to promote stripping resistance of the sealant  300 . 
     For example, a material of the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50  is selected from a group consisting of silicon dioxide, silicon nitride, and silicon oxynitride and combination thereof. For example, all the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50  are silicon dioxide thin films, or are silicon nitride thin films, or are silicon oxynitride thin film. The refractive indices of the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50  are sequentially reduced, and in this case, for ultraviolet light in a wavelength range of 335 nm to 385 nm or ultraviolet light in a wavelength range of 275 nm to 300 nm, the light transmittances of the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50  are sequentially increased. For example, as shown in  FIG.  5   , the refractive indices (RI) of the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50  are 1.95, 1.9 and 1.85 respectively, and for the ultraviolet light in the wavelength range of 335 nm to 385 nm or the ultraviolet light in the wavelength range of 275 nm to 300 nm, their light transmittances are sequentially increased along with increase of the refractive indices. 
     In other embodiments, for example, the materials of the first inorganic layer  11  and the second inorganic layer  12  are the same in chemical composition, and the refractive index of the first inorganic layer  11  is greater than the refractive index of the second inorganic layer  12 ; alternatively, the material of one of the first inorganic layer  11  and the second inorganic layer  12  has same chemical composition with the contact layer  50 , and the refractive index of one of the first inorganic layer  11  and the second inorganic layer  12  is greater than the refractive index of the second inorganic layer  12 . 
     In other embodiments, for example, as shown in  FIG.  6   , a display substrate provided by at least one embodiment of the present disclosure includes a first inorganic layer  21  covering the base substrate  100 A and a second inorganic layer  22  covering the first inorganic layer  21 , both the first inorganic layer  21  and the second inorganic layer  22  overlap with the sealant  300 , and the second inorganic layer  22  is used as the contact layer  50 . 
     It should be noted that  FIG.  6    only shows part of components of the display substrate, and for example, structures such as a conductive layer, a semiconductor layer or an insulation layer and the like, which are not shown in the drawing, are also arranged between the first inorganic layer  21  and the base substrate  100 A. In addition, the arrangement mode of the contact layer  50  and the sealant  300  in the embodiment as shown in  FIG.  6    can refer related description in the embodiment as shown in  FIG.  1 A  and  FIG.  1 B , and the arrangement mode of the organic layer  14  in the embodiment as shown in  FIG.  6    can refer to related description in the embodiment as shown in  FIG.  2 A  and  FIG.  2 B , which are not repeated herein. 
     For example, for the same dry etching process, a dry etching rate of the first inorganic layer  21  is smaller than a dry etching rate of the second inorganic layer  22 . It is beneficial for enabling a via hole simultaneously penetrating the first inorganic layer  21  and the second inorganic layer  22  to have a good appearance so as to ensure an electrical connection between different conductive structures at the position of the via hole. 
     For example, materials of the first inorganic layer  21  and the second inorganic layer  22  are the same in chemical composition and a refractive index of the first inorganic layer  21  is greater than a refractive index of the second inorganic layer  22 , which not only are beneficial for enabling a laminated structure of the first inorganic layer  21  and the second inorganic layer  22  to form the via hole with the good appearance after dry etching, but also can enable the laminated structure to have a high light transmittance. 
     For example, both the first inorganic layer  21  and the second inorganic layer  22  are silicon dioxide thin films, or are silicon nitride thin films or are silicon oxynitride thin films, and the refractive index of the first inorganic layer  21  is greater than the refractive index of the second inorganic layer  22 . In this case, for the ultraviolet light in the wavelength range of 335 nm to 385 nm or the ultraviolet light in the wavelength range of 275 nm to 300 nm, a light transmittance of the first inorganic layer  21  is smaller than a light transmittance of the second inorganic layer  22 , so that the laminated structure of the first inorganic layer  21  and the second inorganic layer  22  has a high light transmittance. 
     At least one embodiment of the present disclosure further provides a display apparatus, which includes the display substrate according to any one of the aforementioned embodiments. 
     For example, the display apparatus provided by the embodiment of the present disclosure can be any product or component with a display function, such as a liquid crystal panel, electronic paper, an Organic Light-Emitting Diode (OLED) panel, a mobile phone, a laptop personal computer, a television, a display, a notebook computer, a digital photo frame, a navigator and the like. 
     At least one embodiment of the present disclosure further provides a manufacturing method of a display substrate. By taking the display substrate as shown in  FIG.  1 A ,  FIG.  2 A ,  FIG.  3    and  FIG.  6    as an example, the method includes: forming the contact layer  50  on the base substrate  100 A; and forming the sealant  300  on the contact layer  50 , the sealant  300  being in contact with the contact layer  50 , such that the contact layer surface  50 A of the contact layer  50 , which is away from the base substrate  100 A, is not flat at the contact position where the contact layer  50  is in contact with the sealant  300 . 
     For example, the sealant  300  is formed by a curing process. For example, the sealant  300  is formed by a light curing (e.g., an ultraviolet curing) process. For example, wet glue for forming the sealant  300  is irradiated by the light from the same side of the base substrate  100  to be cured, so as to obtain the sealant  300 . For example, the sealant  300  is also formed by a thermal curing process. 
     It should be noted that as shown in  FIG.  1 A ,  FIG.  2 A ,  FIG.  3    and  FIG.  6   , the display panel includes a first substrate  100  and a second substrate  200  which are arranged face to face. In the manufacturing method provided by the embodiment of the present disclosure, the wet glue is first coated on the first substrate  100 , and then, the wet glue is connected with the second substrate  200 , next, the wet glue is cured to obtain the sealant  300 ; alternatively, the wet glue is first coated on the second substrate  200 , and then, the wet glue is connected with the first substrate  100 , next, the wet glue is cured to obtain the sealant  300 . 
     For example, the manufacturing method provided by at least one embodiment of the present disclosure further includes: as shown in  FIG.  7   , forming an organic material layer  140  on the base substrate  100 A; and forming the organic layer  14  as shown in  FIG.  2 A ,  FIG.  3    and  FIG.  6    by performing patterning processing on the organic material layer  140 ; the organic layer surface  14 A of the organic layer  14 , which is away from the base substrate  100  A, is not flat at the position of the sealant  300 , so that the contact layer surface  50 A of the contact layer  50  is not flat at the contact position. 
     For example, patterning processing for forming the organic layer  14  includes steps of performing exposure process on the organic material layer  140  by using a mask and performing development process on the exposed material. In this case, the organic layer  14  is produced by adopting a photoresist, and for example, the organic layer  14  adopts a negative photoresist so as to obtain a better water vapor blocking ability; alternatively, patterning processing for forming the organic layer  14  includes steps of coating the photoresist, performing exposure process on the photoresist by using the mask, performing development process on the exposed photoresist to form a photoresist pattern and performing etching process by using the photoresist pattern. 
     For example, for the display substrate as shown in  FIG.  3   , a manufacturing method provided by at least one embodiment of the present disclosure includes: as shown in  FIG.  8 A , sequentially forming a first inorganic material layer  110 , a second inorganic material layer  120  and a contact-layer material layer  500  on the base substrate  100 A. For example, the patterned organic layer  14  is formed after the formation of the first inorganic material layer  110  and the second inorganic material layer  120 , and then the contact-layer material layer  500  is formed on the organic layer  1 . In the same mask process, the patterning processing is performed on the first inorganic material layer  110 , the second inorganic material layer  120  and the contact-layer material layer  500  so as to respectively form the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50 , as shown in  FIG.  8 B . For a dry etching process which the same mask process includes, dry etching rates of the first inorganic material layer  110 , the second inorganic material layer  120  and the contact-layer material layer  500  are sequentially increased. It is beneficial for enabling the via hole  125  simultaneously penetrating the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50  to have a good appearance, i.e., the opening size of the via hole  125  is gradually increased in the direction away from the base substrate, so as to ensure the electrical connection between different conductive structures at the position of the via hole  125 . 
     For example, a mask process includes steps of coating the photoresist, performing exposure process on the photoresist by using a mask, performing development process on the exposed photoresist to form the photoresist pattern and performing dry etching based on the photoresist pattern. 
     For example, materials of the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50  are the same in chemical composition and the refractive indices of the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50  are sequentially reduced, in this way, after dry-etching, a laminated structure of the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50  not only has a high light transmittance, but also makes the via hole  125  having the good appearance. In a case that the sealant  300  is the light curable type sealant, a good curable effect can be obtained so as to promote stripping resistance of the sealant  300 . 
     For example, a material of the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50  is selected from a group consisting of silicon dioxide, silicon nitride, and silicon oxynitride and combination thereof. For example, all the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50  are silicon dioxide thin films, or are silicon nitride thin films or are silicon oxynitride thin film. The refractive indices of the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50  are sequentially reduced, and in this case, in the manufacturing method provided by at least one embodiment of the present disclosure, forming the sealant  300  includes: irradiating the wet glue for forming the sealant  300  from one side of the base substrate  100 A by using ultraviolet light in a wavelength range of 335 nm to 385 nm or ultraviolet light in a wavelength range of 275 nm to 300 nm so as to obtain the cured sealant  300 . 
     For example, the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50  are all formed by using chemical vapor deposition, or plasma enhanced chemical vapor deposition, or other methods. For example, in a case that the first inorganic layer  11 , the second inorganic layer  12  and the contact layer  50  are all the silicon nitride thin films, a plurality of silicon nitride thin films which are the same in chemical composition but different in refractive index are formed by regulating the following parameters, such as a radio frequency power, a pressure in a film forming chamber, concentrations of reaction gases silane (SiH4) and ammonia gas (NH3) and the like. 
     For example, for the display substrate as shown in  FIG.  6   , a manufacturing method provided by at least one embodiment of the present disclosure includes: as shown in  FIG.  9   , sequentially forming a first inorganic material layer  210  and a second inorganic material layer  220  between the base substrate  100 A and the sealant  300 ; and in the same mask process, performing patterning processing on the first inorganic material layer  210  and the second inorganic material layer  220  to respectively form the first inorganic layer  21  and the second inorganic layer  22  as shown in  FIG.  6   , the second inorganic layer  22  being used as the contact layer  50 ; for a dry etching process which the same mask process includes, a dry etching rate of the first inorganic material layer  210  being smaller than a dry etching rate of the second inorganic material layer  220 . 
     For example, both the first inorganic layer  21  and the second inorganic layer  22  are silicon dioxide thin films, or are silicon nitride thin films or are silicon oxynitride thin films, and the refractive indices of the first inorganic layer  21  and the second inorganic layer  22  are sequentially reduced. In this case, in the manufacturing method provided by at least one embodiment of the present disclosure, forming the sealant  300  includes: irradiating the wet glue for forming the sealant  300  from one side of the base substrate  100 A by using ultraviolet light in a wavelength range of 335 nm to 385 nm or ultraviolet light in a wavelength range of 275 nm to 300 nm so as to obtain the cured sealant  300 . 
     For example, both the first inorganic layer  21  and the second inorganic layer  22  are formed by using chemical vapor deposition, or plasma enhanced chemical vapor deposition, or other methods. For example, a plurality of thin films which are the same in chemical composition but different in refractive index can be formed by regulating the following parameters, such as the radio frequency power, the pressure in a film forming chamber, concentrations of reaction gases and the like. 
     In the manufacturing method provided by the embodiments of the present disclosure, the arrangement mode of each component can refer to related description in the embodiments of the display substrate, and is not repeated herein. 
     In view of foregoing, the embodiments of the present disclosure provide the display substrate and the manufacturing method thereof and the display apparatus. The film layer in contact with the sealant has the non-flat surface at the position where the film layer is in contact with the sealant, so that the sealant is a non-flat at a position where the sealant is in contact with the non-flat surface. Thus, the path for the water vapor molecules to enter the sealed region of the display panel from the interface between the sealant and the contact layer can be prolonged, thereby benefiting for increasing the water vapor blocking ability of the display panel. In some embodiments, in a case of forming the sealant by using a light curable process, the transmittance of light for curing the sealant can be increased by enabling the materials of a plurality of inorganic layers between the sealant and the base substrate to be the same in chemical composition and enabling their refractive indices to be sequentially reduced, so as to increase the curing effect and stripping resistance of the sealant. 
     In the disclosure, the following should be noted: 
     (1) The accompanying drawings involve only the structure(s) in connection with the embodiment(s) of the present disclosure, and other structure(s) can be referred to common design(s). 
     (2) For the purpose of clarity only, in accompanying drawings for illustrating the embodiment(s) of the present disclosure, the thickness and a size of a layer or area may be enlarged or narrowed, that is, the drawings are not drawn in a real scale. 
     (3) In case of no conflict, features in one embodiment or in different embodiments can be combined as a new embodiment. 
     What is described above is related to the illustrative embodiments of the disclosure only and not limitative to the scope of the disclosure; the scopes of the disclosure are defined by the accompanying claims.