Patent Publication Number: US-2023136874-A1

Title: Display panel

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The application is a continuation of International Application PCT/CN2021/104547, filed on Jul. 5, 2021, which claims priority to Chinese Patent Application CN202010941775.4, filed on Sep. 9, 2020, the entire contents of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present application relates to the field of display technology, and in particular, to a display panel. 
     BACKGROUND 
     An existing display panel usually includes an isolation layer disposed between an organic light-emitting structure layer and a encapsulation structure. Since the edge of the isolation layer is exposed to the air, which makes water and oxygen easily intrude from the edge, the reliability of the encapsulation is affected. 
     SUMMARY 
     In view of this, the embodiments of the present application provide a display panel to solve the problem in the prior art that the edge of the isolation layer is easy to be intruded by water and oxygen therefrom. 
     The embodiments of the present application provide a display panel, including: an array substrate comprising a display area and a frame area surrounding the display area; a protrusion located in the frame area, the protrusion comprising a first side wall on a side close to the display area and a second side wall on a side away from the display area, at least one of the first side wall and the second side wall comprising a concave area; and an isolation layer stacked on one side of the array substrate and the protrusion, the protrusion being located in an orthographic projection of the isolation layer on the array substrate. 
     According to the display panel provided by the embodiments of the present application, the protrusions are provided, and a concave area is formed on the first side wall and/or the second side wall of the protrusion. In this way, since the concave area is not in the deposition direction, the film needs to be deposited by diffusion of ions or atoms, resulting in a thinning or even disconnection of the film thickness of the subsequently prepared isolation layer in the concave area. In addition, since the reduced thickness of the isolation layer can be effectively suppressed the intrusion of water and oxygen. Therefore, the isolation layer in the concave area can inhibit the intrusion of water and oxygen, thereby reducing the probability of water and oxygen intrusion through the edge of the isolation layer as a whole and improving the reliability of the encapsulation. At the same time, by providing the protrusions, the length of the isolation layer is extended, that is, the invasion path of water and oxygen is extended, thereby further reducing the probability of water and oxygen intrusion and improving the reliability of the encapsulation. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a schematic structural diagram of a display panel according to an embodiment of the present application. 
         FIG.  2    is a schematic structural diagram of a display panel according to another embodiment of the present application. 
         FIG.  3    is a schematic structural diagram of a protrusion provided by an embodiment of the present application. 
         FIG.  4    is a schematic diagram of a manufacturing process of a protrusion provided by an embodiment of the present application. 
         FIG.  5    is a schematic diagram of a manufacturing process of a protrusion according to another embodiment of the present application. 
         FIG.  6    is a structural block diagram of a display device according to an embodiment of the present application. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application. 
       FIG.  1    is a schematic structural diagram of a display panel according to an embodiment of the present application. As shown in  FIG.  1   , the display panel  10  includes an isolation layer  13  disposed between an organic light-emitting structure layer  110  and a encapsulation structure  12 . The isolation layer  13  can block plasma generated in the process of preparing the encapsulation structure  12 , so as to prevent the plasma from adversely affecting the organic light-emitting structure layer  110 , thereby affecting the display effect. The preparation process of the isolation layer  13  uses the same mask as the inorganic encapsulation layer  121  in the encapsulation structure  12 . Therefore, as shown in  FIG.  1   , the isolation layer  13  covers a display area AA where the organic light-emitting structure layer  110  is located, and further extends to a frame area SS of an array substrate  11 . The encapsulation structure  12  does not cover a sidewall of the isolation layer  13 , and the sidewall of the isolation layer  13  is directly exposed to the air. In this case, since a compactness of the isolation layer  13  is lower than a compactness of the inorganic encapsulation layer  121  in the encapsulation structure  12 , water and oxygen in the air are likely to intrude inward from the sidewall of the isolation layer  13 , reducing the reliability of the encapsulation. 
     In view of this, referring to  FIG.  2   , another embodiment of the present application provides a display panel. As shown in  FIG.  2   , a display panel  20  includes an array substrate  21 , an isolation layer  23  and a protrusion  24 . Specifically, the array substrate  21  includes a display area AA and a frame area SS surrounding the display area AA. The protrusion  24  is located in the frame area SS and includes a first side wall  241  on a side close to the display area AA and a second side wall  242  on a side away from the display area AA. At least one of the first side wall  241  and the second side wall  242  includes a concave area. The isolation layer  23  is stacked on one side of the array substrate  21  and the protrusion  24 , and the protrusion  24  is located in an orthographic projection of the isolation layer  23  on the array substrate  21 . 
     The array substrate  21  includes a base substrate and a thin-film transistor (TFT) array formed on the base substrate. The base substrate may be made of any one of a glass material, a metal material, or a plastic material including polyethylene terephthalate, polyethylene naphthalate (PEN), or polyimide. The TFT array can be directly disposed on the base substrate. It should be understood that, in addition to the thin film transistors, the TFT array may also include film layers such as a planarization layer and a passivation layer, which are not limited herein. 
     The isolation layer  23  may be a single film layer or may be a composite film layer composed of a plurality of film layers stacked in sequence. The isolation layer  23  can be prepared by using any inorganic material with water and oxygen barrier function. In one embodiment, the material of the isolation layer  23  is silicon oxide. 
     The array substrate  21  is divided into a display area AA and a frame area SS surrounding the display area AA. The display area AA is provided with an organic light-emitting structure layer  210  for emitting light, the frame area SS is provided with the protrusion  24 , and the barrier layer  23  is stacked on the array substrate  21 , covering the organic light-emitting structure layer  210  and the protrusion  24 . 
     The organic light-emitting structure layer  210  includes a pixel defining layer, a first electrode layer, a light-emitting layer and a second electrode layer which are sequentially provided on the array substrate  21 . The pixel defining layer is provided with an opening to expose the first electrode layer. The light-emitting layer is disposed in the opening of the pixel defining layer and on the exposed first electrode layer. The second electrode layer covers the light-emitting layer. The light-emitting layer may include sub-pixels emitting red light, sub-pixels emitting green light, or sub-pixels emitting blue light. In one embodiment, the first electrode layer is an anode, and the second electrode layer is a cathode. 
     In this embodiment, the height of the protrusion  24  protruding from the surface of the array substrate on which the protrusions are disposed is greater than or equal to 1 micrometer and less than or equal to 10 micrometers. The isolation layer  23  includes a silicon oxide layer. The thickness of the silicon oxide layer is greater than or equal to 5 angstroms and less than or equal to 2000 angstroms. Considering the precision of the existing film forming device, the silicon oxide layer is easier to be prepared when the thickness of the silicon oxide layer is 600 angstroms. 
     The concave area on the first side wall  241  and/or the second side wall  242  of the protrusion  24  refers to the area formed on the first side wall  241  and/or the second side wall  242  that is protruded around and recessed in the middle, that is, the center is recessed toward the interior of the protrusion  24  compared to the periphery. 
     In this case, when the isolation layer  23  is prepared by chemical vapor deposition (CVD) or atomic layer deposition (ALD), since the concave area of the protrusion  24  is not in the deposition direction, the film needs to be deposited by the diffusion of ions or atoms, resulting in the subsequent prepared isolation layer  23  being thinned or even disconnected in the concave area. In addition, since the thickness of the isolation layer  23  is thinned, it is beneficial to inhibit the intrusion of water and oxygen, so the isolation layer  23  in the concave area has a higher ability of water and oxygen inhibition, thereby reducing the probability of water and oxygen intruding inward through the edge of the isolation layer, and improving the reliability of the encapsulation. At the same time, by providing the protrusion  24 , the length of the isolation layer  23  is extended, that is, the water and oxygen intrusion path is extended, thereby further reducing the probability of water and oxygen intrusion and improving the reliability of encapsulation. 
     It should be noted that, the display panel  20  may include a number of protrusions  24 , the number of protrusions are linearly arranged in a direction from the display area AA to the frame area SS. The embodiment of the present application does not limit the number of the protrusions  24 . In one embodiment, the number of protrusions  24  is greater than or equal to three and less than or equal to six. Since the more the number of protrusions  24  is, the stronger the blocking ability against water and oxygen is, but at the same time, the size of the frame area SS also increases accordingly. By setting the number of protrusions  24  to 3-6, a compromise can be achieved between suppressing the intrusion of water and oxygen and reducing the size of the frame. 
       FIG.  3    is a schematic structural diagram of a protrusion provided by an embodiment of the present application. As shown in  FIG.  2    and  FIG.  3   , the protrusion  24  surround the display area AA. The protrusion  24  includes a first cross section S 1  and a second cross section S 2  parallel to the array substrate  21  respectively, and the second cross section S 2  is located between the first cross section S 1  and the array substrate  21 . The orthographic projection of the second cross section S 2  on the first cross section S 1  falls within the first cross section S 1 . In this case, both the first sidewall  241  and the second sidewall  242  corresponding to the protrusion  24  include a concave area  240 , thereby further improving the reliability of encapsulation. 
     Specifically, in one embodiment, as shown in  FIG.  3   , the protrusion  24  includes a first surface B 1  in contact with the array substrate  21  and a second surface B 2  provided opposite to the first surface B 1 , and a width of the protrusion  24  gradually increases from the first surface B 1  to the second surface B 2 . The width of the protrusion  24  refers to the vertical distance between a first intersection line of a cross section parallel to the array substrate  21  with the first side wall  241  of the protrusion  24  and a second intersection line of the cross section parallel to the array substrate  21  with the second side wall  242 . The vertical distance is a length of the vertical line. 
     For example, as shown in  FIG.  2    and  FIG.  3   , in the direction from the display area AA to the frame area SS, the cross section of the protrusion  24  is an inverted trapezoid. In this case, in one embodiment, the protrusion  24  is formed by photocuring a negative photoresist, where the negative photoresist is mainly a polymer containing epoxy groups, vinyl groups or episulfides. In one embodiment, the materials for forming the protrusion  24  include but are not limited to high molecular polymers such as epoxy resin, polymethyl methacrylate, polyimide, and the like. 
     The protrusion  24  with the inverted trapezoid cross-section can be prepared by the following steps.  FIG.  4    is a schematic diagram of a manufacturing process of a protrusion provided by an embodiment of the present application. Referring to  FIG.  4   , specifically, an organic layer  240  is first deposited on an array substrate  21  by means of inkjet printing or silk-screen deposition, and then the organic layer  240  is patterned through exposure and development. For the negative-tone adhesive, the exposure degree decreases as the depth increases, that is, the deeper the position is, the easier it is to be developed. Therefore, the developed negative-tone adhesive forms the protrusion  24  with the inverted trapezoid cross-section. 
     In this embodiment, the included angle θ between the sidewall of the protrusion  24  with the inverted trapezoid cross-section and the array substrate  21  is greater than 0° and less than or equal to 60°. 
     In one embodiment, a frame area SS of the array substrate  21  includes a base substrate and an organic layer on the base substrate, the organic layer includes the protrusion  24 , and the protrusion  24  is located on the surface of the organic layer away from the base substrate, that is, the protrusion  24  and the organic layer are integrally formed. 
     According to the display panel provided in this embodiment, the protrusion  24  with the inverted trapezoid cross-section is formed on the array substrate  21 , and the process is simple and easy to implement. 
     In one embodiment,  FIG.  5    is a schematic diagram of a manufacturing process of a protrusion provided by another embodiment of the present application. As shown in  FIG.  5   , the protrusion  34  includes a first surface B 1  contacting an array substrate  21  and a second surface B 2  provided opposite to the first surface B 1 , and a width of the protrusion  34  decreases first and then increases from the first surface B 1  to the second surface B 2 . 
     For example, as shown in  FIG.  2    and  FIG.  5   , in the direction from the display area AA to the frame area SS, the cross section of the protrusion  34  is approximately I-shaped. In this case, in one embodiment, the protrusion  34  is formed of a metallic material. Since the adhesion between inorganic materials and inorganic materials is stronger than that between organic materials and inorganic materials, the use of metal to form the protrusion  34  can further improve adhesion between the protrusion  34  and isolation layer  23  compared to the use of organic materials to form the protrusion  34 . 
     The protrusion  34  with the I-shaped cross-section can be prepared by the following steps. Referring to  FIG.  5    of the present application, first, a metal layer  340  is deposited on the array substrate  21 , and then a protective adhesive  341  is coated on the metal layer  340 ; then an anisotropic etching process is used, and the etching rate is controlled to increase first and then reduce as the etching depth increases, the protrusion  34  with the I-shaped cross-section is obtained; finally, the protective glue  341  is removed. 
     In one embodiment, the array substrate  21  includes a wiring layer, and the wiring layer includes the protrusion  34 . In this case, the protrusion  34  and the circuit traces in the array substrate  21  are prepared synchronously, and the material that forms the protrusion  34  is the same as that of the circuit traces in the array substrate  21 , such as titanium-aluminum-titanium alloy. Specifically, an opening is further opened at the position corresponding to the edge region SS of the array substrate  21  in the existing mask for preparing the wiring layer, so as to deposit a metal layer in the edge region SS, and then an anisotropic etching process is used to form the protrusion  34  with the I-shaped cross-section. 
     According to the display panel provided in this embodiment, the protrusion  34  with the I-shaped cross-section are formed on the array substrate  21 , and the process is simple and easy to implement. 
     In one embodiment, the display panel  20  provided by any of the embodiments described above further includes a dam located in the frame area SS of the array substrate  21 , as shown in  FIG.  2   . The dam is located on the side of the protrusion  24  close to the display area AA, and the isolation layer  23  further covers the dam. Specifically, the frame area SS of the array substrate  21  is provided with a first dam  251  and a second dam  252  sequentially surrounding the display area AA, and the protrusion  24  surround the second dam  252 . The first dam  251  is used to define the boundary of the organic encapsulation layer  222 , that is, theoretically, the boundary of the organic encapsulation layer  222  terminates at the side of the first dam  251  close to the display area AA. The second dam  252  is used to define the boundary of the first inorganic encapsulation layer  221  and the second inorganic encapsulation layer  223 , that is, theoretically, the boundary of the first inorganic encapsulation layer  221  and the second inorganic encapsulation layer  223  terminates at the second dam  252 . The first dam  251  and the second dam  252  can further block the intrusion of water and oxygen from the edge of the encapsulation structure  22 . 
     It should be understood that due to a certain distance between the mask used in CVD film formation and the array substrate  21 , the first inorganic encapsulation layer  221  and the second inorganic encapsulation layer  223  will cross the second dam  252 , and a shadow area Q of the inorganic encapsulation layer is formed on a side of the second dam  252  away from the display area AA, and the protrusion  24  is located in the shadow area Q of the inorganic encapsulation layer. In this case, the protrusion  24  can function. 
     In one embodiment, as shown in  FIG.  2   , the display panel  20  further includes an encapsulation structure  22  stacked on the side of the isolation layer  23  away from the array substrate  21 , an orthographic projection of the encapsulation structure  22  on the array substrate  21  and an orthographic projection of the isolation layer  23  on the array substrate  21  are coincident. The encapsulation structure  22  includes a first inorganic encapsulation layer  221 , an organic encapsulation layer  222  and a second inorganic encapsulation layer  223  stacked on the array substrate  21  in sequence. In this case, the isolation layer  23  and the inorganic encapsulation layers in the encapsulation structure  22 , that is, the first inorganic encapsulation layer  221  and the second inorganic encapsulation layer  223 , share the same mask, thereby reducing the cost. 
     Specifically, the steps of forming the encapsulation structure  22  are as follows: a first inorganic encapsulation layer  221  is deposited on the display area AA and inside the second dam  252  by a CVD method, and the thickness may be 0.5 μm-1.5 μm. Since there is a certain distance between the mask and the array substrate  21 , the first inorganic encapsulation layer  221  will cross the second dam  252 . Then, an organic material is deposited inside the first dam  251  by inkjet printing, and after leveling and UV curing, an organic encapsulation layer  252  is formed, and the thickness of the organic encapsulation layer  252  may be 4-10 microns. Then, a second inorganic encapsulation layer  223  is again deposited on the organic encapsulation layer  222  within the second dam  252 , and the thickness may be 0.5 micrometers to 1.5 micrometers. Likewise, since there is a certain distance between the mask and the array substrate  21 , the second inorganic encapsulation layer  223  also crosses the second dam  252 . The process of depositing the inorganic encapsulation layer multiple times together forms the shadow area Q of the inorganic barrier layer. 
     In one embodiment, as shown in  FIG.  2   , the frame area SS of the array substrate  21  includes a plurality of film layers stacked in sequence, and one end of the protrusion  24  close to the array substrate  21  is embedded in at least one of the plurality of film layers. 
     For example, in the display panel  20  shown in  FIG.  2   , the frame area SS of the array substrate  21  includes a base substrate and an organic layer on the base substrate, and the protrusion  24  is embedded in the organic layer. In this case, the edge area of the display panel  20  is flexible, the display panel is suitable for preparing a curved screen, and the protrusion  24  is embedded in the organic layer, which can avoid cracks at the position where the protrusion  24  contacts the organic layer during the process of forming the curved screen, thereby improving the reliability. 
     The present application also provides a display device.  FIG.  6    is a structural block diagram of a display device according to an embodiment of the present application. The display device  50  may be a TV, a tablet battery, a mobile phone, or the like. As shown in  FIG.  6   , the display device  50  includes a display panel  51 , a storage module  52  and a processing module  53 . 
     The storage module  52  is used for storing media information. Specifically, the encoder performs analog-to-digital conversion according to coding rules, converts pixel information, such as pixel color, grayscale, contrast, etc., into binary numbers, and stores the binary numbers in the storage module  52 . 
     The processing module  53  is connected to the display panel  51  and the storage module  52  for displaying media information on the display panel  51 . Specifically, the processing module  53  controls the power supply of the power module to the other modules. After the power supply module supplies power, the processing module  53  accepts the image digital information stored in the storage module  52 , performs digital-to-analog conversion on the image digital information, that is, converts the binary digital into original image information, and transmits it to the display panel for display. 
     The display device  50  provided according to the various embodiments of the present application and the display panel provided by any of the above embodiments are based on the same application concept. Details not described in the display device  50  can be found in the display panel, which will not be repeated here. 
     The foregoing description has been presented for the purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of the application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof