Patent Publication Number: US-2023157135-A1

Title: Display panel, method for manufacturing the same and display device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims a priority to the Chinese patent application No. 202010127827.4 filed on Feb. 28, 2020, which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present disclosure relates to the field of display technology, in particular to a display panel, a method for manufacturing the display panel, and a display device. 
     BACKGROUND 
     Along with the development of the display manufacturing technology, a display device has been widely used, and plays an indispensable role in our work and lives. Currently, a Quantum Dot Light-Emitting Diode (QLED) display device has become more and more popular due to such advantages as wide color gamut, high color purity and high color reproduction capability. 
     In the related art, usually Organic Light-Emitting Diode (OLED) is used to excite a quantum dot light-emitting unit to emit colored light. However, when a quantum dot module is pressed against a light-emitting module, an encapsulation film layer of the light-emitting module may be damaged, and the OLED may be easily eroded by moisture and oxygen, leading to an imperfect display effect of the quantum dot display device. 
     SUMMARY 
     In a first aspect, the present disclosure provides in some embodiments a display panel, including: a light-emitting module including an electroluminescent element and a thin film encapsulation layer for encapsulating the electroluminescent element arranged on a first substrate sequentially; a quantum dot module including a plurality of quantum dot light-emitting units spaced apart from each other; and a second substrate located between the light-emitting module and the quantum dot module, and configured to support the quantum dot module at a side of the light-emitting module away from the first substrate. An orthogonal projection of the thin film encapsulation layer onto the first substrate is located within an orthogonal projection of the second substrate onto the first substrate. 
     In a possible embodiment of the present disclosure, the display panel further includes a retaining wall located between the first substrate and the second substrate, and configured to enclose the light-emitting module. 
     In a possible embodiment of the present disclosure, the display panel further includes an optically clear adhesive configured to fill a gap among the retaining wall, the light-emitting module and the second substrate. 
     In a possible embodiment of the present disclosure, the quantum dot module further includes optical sensors electrically coupled to sensing lines and each configured to detect an intensity of light emitted by a corresponding quantum dot light-emitting unit, and the intensity of the light is used as a basis for compensating for a luminous intensity of the electroluminescent element corresponding to the optical sensor. 
     In a possible embodiment of the present disclosure, an orthogonal projection of the optical sensor onto the first substrate partially overlaps an orthogonal projection of the quantum dot light-emitting unit onto the first substrate. 
     In a possible embodiment of the present disclosure, the quantum dot light-emitting units include a red quantum dot light-emitting unit, a green quantum dot light-emitting unit and a blue quantum dot light-emitting unit. A width of an overlapping region between an orthogonal projection of the red quantum dot light-emitting unit onto the first substrate and the orthogonal projection of the corresponding optical sensor onto the first substrate along a row direction of the electroluminescent element is larger than a width of an overlapping region between an orthogonal projection of the green quantum dot light-emitting unit onto the first substrate and the orthogonal projection of the corresponding optical sensor onto the first substrate along the row direction of the electroluminescent element; and/or a width of an overlapping region between an orthogonal projection of the blue quantum dot light-emitting unit onto the first substrate and the orthogonal projection of the corresponding optical sensor onto the first substrate along the row direction of the electroluminescent element is larger than the width of the overlapping region between the orthogonal projection of the green quantum dot light-emitting unit onto the first substrate and the orthogonal projection of the corresponding optical sensor onto the first substrate along the row direction of the electroluminescent element. 
     In a possible embodiment of the present disclosure, a black matrix is provided between adjacent quantum dot light-emitting units. 
     In a possible embodiment of the present disclosure, the quantum dot module further includes a plurality of supporting structures, each supporting structure is located between a corresponding black matrix and the second substrate to define an accommodation space between the corresponding black matrix and the second substrate, and a corresponding optical sensor is located in the accommodation space. 
     In a possible embodiment of the present disclosure, the quantum dot module further includes a plurality of light-shielding structures, each light-shielding structure is located between the corresponding supporting structure and the second substrate, each optical sensor is arranged at a side of the corresponding light-shielding structure away from the light-emitting module, and an orthogonal projection of the optical sensor onto the first substrate is located within an orthogonal projection of the corresponding light-shielding structure onto the first substrate. 
     In a possible embodiment of the present disclosure, the quantum dot module further includes a plurality of supporting structures, each supporting structure is located at a side of a corresponding black matrix away from the second substrate to define an accommodation space at the side of the corresponding black matrix away from the second substrate, and a corresponding optical sensor is located in the accommodation space. 
     In a possible embodiment of the present disclosure, the quantum dot module further includes a plurality of light-shielding structures, each light-shielding structure abuts against a surface of a corresponding supporting structure away from the second substrate, each optical sensor is arranged at a side of the corresponding light-shielding structure close to the second substrate, and an orthogonal projection of the optical sensor onto the first substrate is within an orthogonal projection of the corresponding light-shielding structure onto the first substrate. 
     In a possible embodiment of the present disclosure, the supporting structure is made of a black material. 
     In a possible embodiment of the present disclosure, an anti-crosstalk structure is further provided at a side of the second substrate close to the first substrate, and an orthogonal projection of a gap between two adjacent quantum dot light-emitting units onto the first substrate is located within an orthogonal projection of the anti-crosstalk structure onto the first substrate. 
     In a second aspect, the present disclosure provides in some embodiments a method for manufacturing a display panel, including: providing a first substrate, and sequentially forming an electroluminescent element and a thin film encapsulation layer on the first substrate; providing a second substrate, and forming a quantum dot module on the second substrate, the quantum dot module including a plurality of quantum dot light-emitting units spaced apart from each other; and encapsulating the second substrate onto the thin film encapsulation layer. An orthogonal projection of the thin film encapsulation layer onto the first substrate is located within an orthogonal projection of the second substrate onto the first substrate. 
     In a possible embodiment of the present disclosure, the forming the quantum dot module on the second substrate includes: forming light-shielding structures on the second substrate; forming optical sensors and supporting structures at a side of each light-shielding structure away from the second substrate, an orthogonal projection of each optical sensor onto the first substrate and an orthogonal projection of each supporting structure onto the first substrate not overlapping each other and being located within an orthogonal projection of the corresponding light-shielding structure onto the first substrate; forming a black matrix at a side of each supporting structure away from the second substrate; and forming each quantum dot light-emitting unit between two adjacent black matrices, an orthogonal projection of each quantum dot light-emitting unit onto the first substrate partially overlapping the orthogonal projection of the corresponding optical sensor onto the first substrate. 
     In a possible embodiment of the present disclosure, the forming the quantum dot module on the second substrate includes: forming black matrices and the quantum dot light-emitting units each located between two adjacent black matrices on the second substrate; providing a third substrate, and forming light-shielding structures on the third substrate; forming an optical sensor and a supporting structure at a side of each light-shielding structure away from the third substrate, an orthogonal projection of the optical sensor onto the third substrate and an orthogonal projection of the supporting structure onto the third substrate not overlapping each other and being located within an orthogonal projection of the corresponding light-shielding structure onto the third substrate; and encapsulating the third substrate at a side of each quantum dot light-emitting unit away from the second substrate, the optical sensors, the supporting structures and the light-shielding structures being located between the third substrate and the second substrate, and an orthogonal projection of each quantum dot light-emitting unit onto the second substrate partially overlapping the orthogonal projection of the corresponding optical sensor onto the second substrate. 
     In a third aspect, the present disclosure provides in some embodiments a display device, including the above-mentioned display panel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to illustrate the technical solutions of the embodiments of the present disclosure in a clearer manner, the drawings required for the description of the embodiments of the present disclosure will be described hereinafter briefly. Obviously, the following drawings merely relate to some embodiments of the present disclosure, and based on these drawings, a person of ordinary skill in the art may obtain other drawings without any creative effort. 
         FIG.  1    is a schematic view showing a display panel according to one embodiment of the present disclosure; 
         FIG.  2    is a schematic view showing an optical sensor in the display panel according to one embodiment of the present disclosure; 
         FIG.  3    is a schematic view showing a layer structure of the optical sensor according to one embodiment of the present disclosure; 
         FIG.  4    is a schematic view showing a size of each structure in a quantum dot module in  FIG.  1   ; 
         FIG.  5    is another schematic view showing the display panel according to one embodiment of the present disclosure; 
         FIGS.  6   a  to  6   f    are schematic views showing the manufacture of the quantum dot module in the display panel according to one embodiment of the present disclosure; and 
         FIG.  7   a    and  FIG.  7   b    are schematic views showing two parts for encapsulation in the quantum dot module of the display panel according to one embodiment of the present disclosure. 
     
    
    
     REFERENCE SIGN LIST 
     
         
           110  light-emitting module 
           111  electroluminescent element 
           111 A anode 
           111 B cathode 
           111 C light-emitting layer 
           111 D pixel definition layer 
           112  thin film encapsulation layer 
           113  thin film transistor array layer 
           120  first substrate 
           130  quantum dot module 
           131  quantum dot light-emitting unit 
           132  color filter layer 
           133  optical sensor 
           134  black matrix 
           135  supporting structure 
           136  light-shielding structure 
           137  anti-crosstalk structure 
           140  second substrate 
           150  retaining wall 
           160  optically clear adhesive 
           170  third substrate 
           171  first planarization layer 
           172  second planarization layer 
           173  third planarization layer 
           174  fourth planarization layer 
           181  first inorganic layer 
           182  second inorganic layer 
           183  third inorganic layer 
           184  fourth inorganic layer 
           185  fifth inorganic layer 
           186  sixth inorganic layer. 
       
    
     DETAILED DESCRIPTION 
     In order to make the objects, the technical solutions and the advantages of the present disclosure more apparent, the present disclosure will be described hereinafter in a clear and complete manner in conjunction with the drawings and embodiments. Obviously, the following embodiments merely relate to a part of, rather than all of, the embodiments of the present disclosure, and based on these embodiments, a person skilled in the art may, without any creative effort, obtain the other embodiments, which also fall within the scope of the present disclosure. 
     An object of the present disclosure is to provide a display panel, a method for manufacturing the display panel, and a display device, so as to solve the problem in the related art where an OLED is easily eroded by moisture and oxygen and thereby an imperfect display effect occurs for a quantum dot display device when a quantum dot module is pressed against a light-emitting module and an encapsulation film layer of the light-emitting module is damaged. 
     The present disclosure provides in some embodiments a display panel which, as shown in  FIG.  1   , includes: a light-emitting module  110  including an electroluminescent element  111  and a thin film encapsulation layer  112  for encapsulating the electroluminescent element  111  arranged on a first substrate  120  sequentially; a quantum dot module  130  including a plurality of quantum dot light-emitting units  131  spaced apart from each other; and a second substrate  140  located between the light-emitting module  110  and the quantum dot module  130 , and configured to support the quantum dot module  130  at a side of the light-emitting module  110  away from the first substrate  120 . An orthogonal projection of the thin film encapsulation layer  112  onto the first substrate  120  is located within an orthogonal projection of the second substrate  140  onto the first substrate  120 . 
     According to the embodiments of the present disclosure, the second substrate is arranged between the light-emitting module and the quantum dot module, and a weight of the quantum dot module is applied onto the thin-film encapsulation layer of the light-emitting module through the second substrate, so it is able to reduce a pressure applied onto the thin film encapsulation layer, prevent the thin film encapsulation layer from being damaged, and prevent moisture and oxygen from entering the electroluminescent element, thereby to ensure luminous efficiency of the electroluminescent element and a display effect of the display device. 
     The light-emitting module  110  is formed on the first substrate  120  and includes the electroluminescent element  111  and the thin film encapsulation layer  112 . The electroluminescent element  111  is used to emit basic light, such as blue light, that excites the quantum dot light-emitting unit  131  to emit light. The thin-film encapsulation layer  112  is used to prevent external moisture and oxygen from entering the light-emitting module  110  to erode the electroluminescent element, thereby to prevent the luminous efficiency of the electroluminescent element from being deteriorated. The thin film encapsulation layer includes an inorganic film layer and an organic film layer. 
     The electroluminescent element  111  includes an anode  111 A, a cathode  111 B and a light-emitting layer  111 C. The anode  111 A is located between the first substrate  120  and the light-emitting layer  111 C, the cathode layer  111 B is located between the light-emitting layer  111 C and the thin film encapsulation layer  112 . The light-emitting layer  111 C is coupled to the anode  111 A and the cathode  111 B. In a possible embodiment of the present disclosure, an orthogonal projection of the light-emitting layer  111 C onto the first substrate  120  is located within an orthogonal projection of the anode  111 A onto the first substrate  120 . 
     In the embodiments of the present disclosure, the electroluminescent element  111  is an OLED. Under the effect of an electric field formed by the anode  111 A and the cathode  111 B, holes generated by the anode  111 A and electrons generated by the cathode  111 B move toward a hole transport layer and an electron transport layer respectively, and migrate to the light-emitting layer  111 C, so as to generate energy to excite visible light. 
     A pixel definition layer  111 D is further arranged between the cathode  111 B and the anode  111 A, and configured to insulate the light-emitting layers  111 C of two adjacent electroluminescent elements  111  from each other. 
     The light-emitting module  110  further includes other structures, such as a thin film transistor array layer  113  used to control an electric signal for the electroluminescent element  111 , a buffer layer, an insulation layer, etc., which will not be particularly defined herein. 
     The quantum dot module  130  is formed on the second substrate  140  and includes the plurality of quantum dot light-emitting units  131  spaced apart from each other. The quantum dot light-emitting units  131  include quantum dot light-emitting units in different colors arranged in a preset order. The quantum dot light-emitting units include a red quantum dot light-emitting unit, a green quantum dot light-emitting unit and a blue quantum dot light-emitting unit. Of course, the quantum dot light-emitting units also include other color quantum dot light-emitting units, such as a white quantum dot light-emitting unit. When the basic light is blue light, the blue quantum dot light-emitting unit  131  is a blue transparent layer. 
     The quantum dot module  130  further includes other structures, such as a color filter layer  132  at a light-exiting side of each quantum dot light-emitting unit  131 . The color filter layer  132  is arranged in such a manner as to correspond to a color of the quantum dot light-emitting unit  131 , and configured to allow target light emitted through exciting the color filter layer  132  to pass therethrough and block the basic light. When the basic light is blue light, a blue color filter layer is used to allow the blue light to pass therethrough and block light in the other colors. 
     The weight of the quantum dot module  130  supported by the second substrate  140  is applied onto the thin-film encapsulation layer  112 . Due to a large force bearing area, the pressure is small, so it is able to prevent the thin film encapsulation layer  112  from being damaged, thereby to prevent moisture and oxygen from entering the light-emitting module  110  through the thin-film encapsulation layer  112 . 
     In addition, the quantum dot module  130  is entirely pressed against the second substrate  140 , so it is able to further prevent the deformation of the quantum dot light-emitting units  131  when the light-emitting module  110  and the quantum dot module  130  are arranged opposite to each other, and improve the uniformity of light emission of the quantum dot light-emitting units  131 , thereby to improve the display quality of the display device. 
     In a possible embodiment of the present disclosure, the display panel further includes a retaining wall  150  located between the first substrate  120  and the second substrate  140 , and configured to enclose the light-emitting module  110 . The display panel further includes an optically clear adhesive  160  configured to fill a gap among the retaining wall  150 , the light-emitting module  110  and the second substrate  140 . 
     The second substrate  140  supported by the retaining wall  150  and the first substrate  120  are arranged opposite to each other for the encapsulation, and the retaining wall  150  is used to carry a weight of the second substrate  140 . When the gap among the retaining wall  150 , the light-emitting module  110  and the second substrate  140  is filled with the optically clear adhesive  160 , it is able to fix positions of the retaining wall  150 , the light-emitting module  110  and the second substrate  140 . In addition, the optically clear adhesive  160  also carries a part of the weight of the second substrate  140 , so as to protect the thin film encapsulation layer  112  of the light-emitting module  110 . 
     In a possible embodiment of the present disclosure, as shown in  FIG.  1   , the quantum dot module  130  further includes optical sensors  133  electrically coupled to sensing lines and each configured to detect an intensity of light emitted by a corresponding quantum dot light-emitting unit  131 . The intensity of the light is used as a basis for compensating for a luminous intensity of the electroluminescent element corresponding to the optical sensor. 
     In the embodiments of the present disclosure, each quantum dot light-emitting unit  131  corresponds to one optical sensor  133  for measuring the intensity of light emitted by the quantum dot light-emitting unit  131 . To be specific, as shown in  FIG.  2   , the optical sensor  133  includes a switching unit  1331  and a photodiode  1332 . A switching unit  1331  is used to control an output end of the photodiode  1332  to be electrically coupled to a sensing line Sense. The sensing line Sense is used to transmit an electric signal outputted by the photodiode  1332  to an integrated circuit (such as a field programmable logic gate array). The integrated circuit is configured to determine the luminous intensity of each quantum dot light-emitting unit  131  through analyzing the electric signal outputted by the photodiode  1332 , and determine a compensation value for the electroluminescent element  111  corresponding to each quantum dot light-emitting unit  131 , so as to compensate for the light emitted by the electroluminescent element  111 . 
     As shown in  FIG.  2   , the display panel includes a constant-voltage line V 0 , a scanning line Scan and the sensing line Sense. A first end of the photodiode  1332  is coupled to the constant-voltage line V 0 , and a second end of the photodiode  1332  is coupled to an input end of the switching unit  1331 . An output end of the switching unit  1331  is coupled to the sensing line Sense, and a control end of the switching unit  1331  is coupled to the scanning line Scan. Under the control of a scanning signal from the scanning line Scan, the switching unit  1321  controls the second end of the photodiode  1332  to be electrically coupled to the sensing line Sense, so as to write the electric signal from the photodiode  1332  into the sensing line Sense. 
     The switching unit  1331  is an N-type thin film transistor, the input end of the switching unit  1331  is a source electrode of the N-type thin film transistor, the output end of the N-type thin film transistor  1331  is a drain electrode of the N-type thin film transistor, and the control electrode of the N-type thin film transistor  1331  is a gate electrode of the N-type thin film transistor. Of course, the switching unit  1331  is also a P-type thin film transistor, a triode, etc., which will not be particularly defined herein. 
     A film structure of the optical sensor  133  in the display panel is shown in  FIG.  3   . In  FIG.  3 ,  301    represents the constant-voltage line V 0 ,  302  represents the photodiode  1332 ,  303  represents the control end of the switching unit  1331  connected to the scanning line Scan, and  304  represents the sensing line Sense. 
     Further, an orthogonal projection of each optical sensor  133  onto the first substrate  120  partially overlaps an orthogonal projection of the corresponding quantum dot light-emitting unit  131  onto the first substrate  120 . 
     As shown in  FIG.  4   , a width a of the optical sensor  133  in a direction parallel to the second substrate  140  ranges from 2 μm to 25 μm. In a possible embodiment of the present disclosure, a width of the optical sensor used to measure the luminous intensity of the green quantum dot light-emitting unit is 5.2 μm, and a width of the optical sensor used to measure the luminous intensity of each of the red quantum dot light-emitting unit and the blue quantum dot light-emitting unit is 9.5 μm. 
     A width b of the quantum dot light-emitting unit  131  in the direction parallel to the second substrate  140  ranges from 10 μm to 200 μm. In a possible embodiment of the present disclosure, a width of the green quantum dot light-emitting unit  131  in the direction parallel to the second substrate  140  is 52 μm, and a width of each of the red quantum dot light-emitting unit and the blue quantum dot light-emitting unit in the direction parallel to the second substrate  140  is 95 μm. 
     A height c of the quantum dot light-emitting unit  131  in a direction perpendicular to the second substrate  140  ranges from 1 μm to 20 μm, e.g., 12 μm. 
     In the embodiments of the present disclosure, an overlapping width of an overlapping region between the orthogonal projection of the optical sensor  133  onto the first substrate  120  and the orthogonal projection of the quantum dot light-emitting unit  131  onto the first substrate  120  ranges from 2 μm to 18 μm. In a possible embodiment of the present disclosure, an overlapping width of an overlapping region between the orthogonal projection of the optical sensor  133  onto the first substrate  120  and an orthogonal projection of the green quantum dot light-emitting unit  131  onto the first substrate  120  is 2.6 μm, and an overlapping width of an overlapping region between the orthogonal projection of the optical sensor  133  onto the first substrate  120  and an orthogonal projection of the red quantum dot light-emitting unit or the blue quantum dot light-emitting unit onto the first substrate  120  is 5.1 μm. 
     A width of an overlapping region between an orthogonal projection of the red quantum dot light-emitting unit onto the first substrate and the orthogonal projection of the corresponding optical sensor onto the first substrate along a row direction of the electroluminescent element is larger than a width of an overlapping region between an orthogonal projection of the green quantum dot light-emitting unit onto the first substrate and the orthogonal projection of the corresponding optical sensor onto the first substrate along the row direction of the electroluminescent element; and/or, a width of an overlapping region between an orthogonal projection of the blue quantum dot light-emitting unit onto the first substrate and the orthogonal projection of the corresponding optical sensor onto the first substrate along the row direction of the electroluminescent element is larger than the width of the overlapping region between the orthogonal projection of the green quantum dot light-emitting unit onto the first substrate and the orthogonal projection of the corresponding optical sensor onto the first substrate along the row direction of the electroluminescent element. 
     The width along the row direction of the electroluminescent element refers to a horizontal length in  FIG.  4   . 
     A ratio of the overlapping width to the width of the quantum dot light-emitting unit approximately ranges from 0.040 to 0.065, and a ratio of the width of the optical sensor to the width of the quantum dot light-emitting unit approximately ranges from 0.08 to 0.120. 
     It should be appreciated that, luminous efficiency of a green sub-pixel is larger than luminous efficiency of a blue sub-pixel and luminous efficiency of a red sub-pixel, so a size of the green quantum dot light-emitting unit is smaller than a size of the blue sub-pixel and a size of the red sub-pixel. Based on a preset ratio, sizes of the optical sensor and color filter layer corresponding to the green quantum dot light-emitting unit are also smaller than sizes of the optical sensor and color filter layer corresponding to the quantum dot light-emitting unit in the other colors. 
     In this way, it is able for the optical sensor  133  to directly sense the light from the quantum dot light-emitting unit  131 . In addition, the optical sensor  133  overlaps the quantum dot light-emitting unit  131  to a small extent, so it is able to reduce a region where the light is shielded by the optical sensor  133 . 
     In addition, in the case that the quantum dot module  130  further includes the color filter layer  132 , a width d of the color filter layer  132  in the direction parallel to the second substrate  140  ranges from 10 μm to 200 μm. In a possible embodiment of the present disclosure, the width of the color filter layer corresponding to the green quantum dot light-emitting unit in the direction parallel to the second substrate  140  is 67 μm, and the width of the color filter layer corresponding to the red quantum dot light-emitting unit or the blue quantum dot light-emitting unit in the direction parallel to the second substrate  140  is 110 μm. 
     A height e of the color filter layer  132  in the direction perpendicular to the second substrate  140  ranges from 1 μm to 10 μm, e.g., 1.6 μm. 
     Further, a black matrix  134  is provided between adjacent quantum dot light-emitting units  131 . 
     Through the black matrix  134 , it is able to prevent the basic light from passing through a gap between the adjacent quantum dot light-emitting units  131 . The color filter layer  132  only corresponds to a region where the quantum dot light-emitting unit  131  is located, and the basic light passing through the gap between adjacent quantum dot light-emitting units  131  is not blocked by the color filter layer  132 . At this time, a ratio of the basic light in display light is reduced, and thereby the display effect of the display device is adversely affected. 
     A height of the black matrix  134  in the direction perpendicular to the second substrate  140  is the same as the height c of the quantum dot light-emitting unit  131  in the direction perpendicular to the second substrate  140 , and ranges from 1 μm to 20 μm, e.g., 12 μm. 
     In a possible embodiment of the present disclosure, as shown in  FIG.  1   , the quantum dot module  130  further includes a plurality of supporting structures  135 , each supporting structure  135  is located between the corresponding black matrix  134  and the second substrate  140  to define an accommodation space between the corresponding black matrix  134  and the second substrate  140 , and a corresponding optical sensor  133  is located in the accommodation space. 
     The quantum dot module  130  further includes the supporting structure  135  located between the corresponding black matrix  134  and the second substrate  140  to define the accommodation space for accommodating the corresponding optical sensor  133  between the corresponding black matrix  134  and the second substrate  140 . 
     An orthogonal projection of each supporting structure  135  onto the second substrate  140  is located within an orthogonal projection of the corresponding black matrix  134  onto the second substrate  140 . As shown in  FIG.  4   , a height f of the supporting structure  135  in the direction perpendicular to the second substrate  140  ranges from 1 μm to 10 μm, e.g., 4.5 μm. 
     In the embodiments of the present disclosure, apart from defining a space for accommodating the optical sensor  133  between the second substrate  140  and the black matrix  134  (the quantum dot light-emitting unit  131 ), the supporting structure  135  is also made of a black material so as to isolate light path spaces corresponding to the quantum dot light-emitting units  131  from each other, prevent the light emitted by the quantum dot light-emitting units  131  from interfering with each other, and enable the optical sensor  133  to only detect the light emitted by the corresponding quantum dot light-emitting unit  131  without being affected by the light emitted by the other quantum dot light-emitting units  131 , thereby to improve the accuracy of luminous compensation as well as the display effect of the display device. 
     As shown in  FIG.  1   , the quantum dot module  130  further includes a plurality of light-shielding structures  136 , each light-shielding structure  136  is located between the corresponding retaining wall  135  and the second substrate  140 , each optical sensor  133  is arranged at a side of the corresponding light-shielding structure  136  away from the light-emitting module  110 , and an orthogonal projection of each optical sensor  133  onto the first substrate  120  is located within an orthogonal projection of the corresponding light-shielding structure  136  onto the first substrate  120 . 
     In the embodiments of the present disclosure, the light-shielding structure  136  is formed at a side of the second substrate  140  close to the optical sensor  133 , and the orthogonal projection of the optical sensor  133  onto the first substrate  120  is located within the orthogonal projection of the corresponding light-shielding structure  136  onto the first substrate  120 , that is, the light-shielding structure  136  is configured to block the light from a side of the second substrate  140  away from the optical sensor  133 , so as to prevent the optical sensor  133  from being adversely affected by the light emitted by the light-emitting module  110  during the measurement, thereby to improve the accuracy of luminous compensation as well as the display effect of the display device. 
     A width g of the light-shielding structure  136  in the direction parallel to the second substrate  140  ranges from 10 μm to 100 μm, e.g., 30 μm. A spacing h between adjacent light-shielding structures  136  in the direction parallel to the second substrate  140  ranges from 10 μm to 200 μm. A spacing corresponding to the green quantum dot light-emitting unit is 60 μm, and a spacing corresponding to each of the red quantum dot light-emitting unit and the blue quantum dot light-emitting unit is 90 μm. 
     In another possible embodiment of the present disclosure, as shown in  FIG.  5   , the quantum dot module  130  further includes a plurality of supporting structures  135 , each supporting structure  135  is located at a side of the corresponding black matrix  134  away from the second substrate  140  to define an accommodation space on the side of the corresponding black matrix  134  away from the second substrate  140 , and a corresponding optical sensor  133  is located in the accommodation space. 
     The quantum dot module  130  further includes the supporting structure  135  located between the black matrix  134  and a third substrate  170  and configured to define the accommodation space for accommodating the optical sensor  133  between the black matrix  134  and the third substrate  170 . 
     In the embodiments of the present disclosure, an orthogonal projection of the supporting structure  135  onto the second substrate  140  is within an orthogonal projection of the corresponding black matrix  134  onto the second substrate  140 . A height f of the supporting structure  135  in the direction perpendicular to the second substrate  140  in  FIG.  4    ranges from 1 μm to 10 μm, e.g., 4.5 μm. 
     In the embodiments of the present disclosure, apart from defining a space for accommodating the optical sensor  133  between the third substrate  170  and the black matrix  134  (the quantum dot light-emitting unit  131 ), the supporting structure  135  is also made of a black material, so as to isolate light path spaces corresponding to the quantum dot light-emitting units  131  from each other, prevent the light emitted by the quantum dot light-emitting units  131  from interfering with each other, and enable the optical sensor  133  to only detect the light emitted by the corresponding quantum dot light-emitting unit  131  without being adversely affected by the light emitted by the surrounding quantum dot light-emitting units  131 , thereby to improve the accuracy of luminous compensation as well as the display effect of the display device. 
     As shown in  FIG.  5   , the quantum dot module  130  further includes a plurality of light-shielding structures  136 , each light-shielding structure  136  abuts against a surface of the corresponding supporting structure  135  away from the second substrate  140 , each optical sensor  133  is arranged at a side of the corresponding light-shielding structure  136  close to the second substrate  140 , and an orthogonal projection of the optical sensor  133  onto the first substrate  110  is located within an orthogonal projection of the light-shielding structure  136  onto the first substrate  110 . 
     In the embodiments of the present disclosure, the light-shielding structure  136  is formed at a side of the third substrate  160  close to the optical sensor  133 , the optical sensor  133  is formed at a side of the light-shielding structure  136  close to the second substrate  140 , and the third substrate  160  and the second substrate  140  are arranged opposite to each other for encapsulation. 
     In the embodiments of the present disclosure, the orthogonal projection of the optical sensor  133  onto the first substrate  120  is located within the orthogonal projection of the light-shielding structure  136  onto the first substrate  120 , that is, the light-shielding structure  136  is configured to block the light from a side of the third substrate  160  away from the optical sensor  133 , so as to prevent the optical sensor  133  from being adversely affected by the light from the side of the third substrate  160  away from the optical sensor  133  during measurement, thereby to improve the accuracy of luminous compensation as well as the display effect of the display device. 
     In addition, in the other embodiments of the present disclosure, as shown in  FIG.  1    and  FIG.  5   , an anti-crosstalk structure  137  is further provided at a side of the second substrate  140  close to the first substrate  120 , and an orthogonal projection of a gap between two adjacent quantum dot light-emitting units  131  onto the first substrate  120  is located within an orthogonal projection of the anti-crosstalk structure  137  onto the first substrate  120 , so as to prevent light emitted by the quantum dot light-emitting unit in a first color from entering the quantum dot light-emitting unit in a second color. 
     In the embodiments of the present disclosure, the anti-crosstalk structure  137  is configured to prevent the light emitted by the quantum dot light-emitting unit  131  from diffracting from the second substrate  140  into spaces corresponding to other quantum dot light-emitting units  131 . In addition, the anti-crosstalk structure  137  is further configured to absorb the light emitted by the light-emitting module  110  that is beyond the region where the quantum dot light-emitting unit  131  is located, so as to enable each quantum dot light-emitting unit  131  to receive the uniform basic light. 
     It should be appreciated that, inorganic material layers deposited through chemical vapor deposition (CVD) are further provided between various structures in the quantum dot module  130 , and each inorganic material layer is made of silicon nitride, silicon oxynitride, silicon oxide, etc. Through the inorganic material layers, it is able to prevent moisture and oxygen from entering the light-emitting module  110  and ensure the luminous efficiency of the quantum dot module  130 . For example, in  FIG.  1   , a first inorganic layer  181  is deposited between the optical sensor  133  and the light-shielding structure  136 . For another example, in  FIG.  5   , a fourth inorganic layer  184  is deposited between the quantum dot light-emitting unit  131  and the color filter layer  132 . 
     The present disclosure further provides in some embodiments a method for manufacturing a display panel, which includes: providing a first substrate, and sequentially forming an electroluminescent element and a thin film encapsulation layer on the first substrate; providing a second substrate, and forming a quantum dot module on the second substrate, the quantum dot module including a plurality of quantum dot light-emitting units spaced apart from each other; and encapsulating the second substrate onto the thin film encapsulation layer, an orthogonal projection of the thin film encapsulation layer onto the first substrate being located within an orthogonal projection of the second substrate onto the first substrate 
     According to the embodiments of the present disclosure, the second substrate is arranged between the light-emitting module and the quantum dot module, and a weight of the quantum dot module is applied onto the thin-film encapsulation layer of the light-emitting module through the second substrate, so it is able to reduce a pressure applied onto the thin film encapsulation layer, prevent the thin film encapsulation layer from being damaged, and prevent moisture and oxygen from entering the electroluminescent element, thereby to ensure luminous efficiency of the electroluminescent element and a display effect of the display device. 
     As shown in  FIG.  1   , the light-emitting module  110  is formed on the first substrate  120  and includes the electroluminescent element  111  and the thin film encapsulation layer  112 . The electroluminescent element  111  is used to emit basic light, such as blue light, that excites the quantum dot light-emitting unit  131  to emit light. The thin-film encapsulation layer  112  is used to prevent external moisture and oxygen from entering the light-emitting module  110  to erode the electroluminescent element, thereby to prevent the luminous efficiency of the electroluminescent element from being deteriorated. The thin film encapsulation layer includes an inorganic film layer and an organic film layer. 
     The electroluminescent element  111  includes an anode  111 A, a cathode  111 B and a light-emitting layer  111 C. The anode  111 A is located between the first substrate  120  and the light-emitting layer  111 C, the cathode  111 B is located between the light-emitting layer  111 C and the thin film encapsulation layer  112 . The light-emitting layer  111 C is coupled to the anode  111 A and the cathode  111 B. In a possible embodiment of the present disclosure, an orthogonal projection of the light-emitting layer  111 C onto the first substrate  120  is located within an orthogonal projection of the anode  111 A onto the first substrate  120 . 
     In the embodiments of the present disclosure, the electroluminescent element  111  is an OLED. Under the effect of an electric field formed by the anode  111 A and the cathode  111 B, holes generated by the anode  111 A and electrons generated by the cathode  111 B move toward a hole transport layer and an electron transport layer respectively, and migrate to the light-emitting layer  111 C, so as to generate energy to excite visible light. 
     A pixel definition layer  111 D is further included between the cathode  111 B and the anode  111 A, and configured to insulate light-emitting layers  111 C of two adjacent electroluminescent elements  111  from each other. 
     The light-emitting module  110  further includes other structures, such as a thin film transistor array layer  113  used to control an electric signal for the electroluminescent element  111 , a buffer layer, an insulation layer, etc., which will not be particularly defined herein. 
     The quantum dot module  130  is formed on the second substrate  140  and includes the plurality of quantum dot light-emitting units  131  spaced apart from each other. The quantum dot light-emitting units  131  include quantum dot light-emitting units in different colors arranged in a preset order. The quantum dot light-emitting units include a red quantum dot light-emitting unit, a green quantum dot light-emitting unit and a blue quantum dot light-emitting unit. Of course, the quantum dot light-emitting units also include other color quantum dot light-emitting units, such as a white quantum dot light-emitting unit. When the basic light is blue light, the blue quantum dot light-emitting unit  131  is a blue transparent layer. 
     The quantum dot module  130  further includes other structures, such as a color filter layer  132  at a light-exiting side of each quantum dot light-emitting unit  131 . The color filter layer  132  is arranged in such a manner as to correspond to a color of the quantum dot light-emitting unit  131 , and configured to allow target light emitted through exciting the color filter layer  132  to pass therethrough and block the basic light. When the basic light is blue light, a blue color filter layer is used to allow the blue light to pass therethrough and block light in the other colors. 
     The weight of the quantum dot module  130  supported by the second substrate  140  is applied onto the thin-film encapsulation layer  112 . Due to a large force bearing area, the pressure is small, so it is able to prevent the thin film encapsulation layer  112  from being damaged, thereby to prevent moisture and oxygen from entering the light-emitting module  110  through the thin-film encapsulation layer  112 . 
     In addition, the quantum dot module  130  is entirely pressed against the second substrate  140 , so it is able to further prevent the deformation of the quantum dot light-emitting units  131  when the light-emitting module  110  and the quantum dot module  130  are arranged opposite to each other, and improve the uniformity of light emission of the quantum dot light-emitting units  131 , thereby to improve the display quality of the display device. 
     Further, the forming the quantum dot module on the second substrate includes: forming light-shielding structures on the second substrate; forming an optical sensor and a supporting structure at a side of each light-shielding structure away from the second substrate, an orthogonal projection of the optical sensor onto the first substrate and an orthogonal projection of the supporting structure onto the first substrate not overlapping each other and being located within an orthogonal projection of the light-shielding structure onto the first substrate; forming a black matrix at a side of the supporting structure away from the second substrate; and forming a quantum dot light-emitting unit between two adjacent black matrices, an orthogonal projection of each quantum dot light-emitting unit onto the first substrate partially overlapping the orthogonal projection of the corresponding optical sensor onto the first substrate. 
     In the embodiments of the present disclosure, as shown in  FIG.  6   a   , the light-shielding structures  136  are formed on the second substrate  140 . Before the formation of the light-shielding structures  136 , the anti-crosstalk structures  137  are further formed on a surface of the second substrate  140  opposite to the first substrate  120 . After the formation of the light-shielding structures  136 , a first planarization layer  171  is formed. A surface of the first planarization layer  171  away from the second substrate  140  is flush with a surface of each light-shielding structure  136  away from the second substrate  140 . After the formation of the first planarization layer  171 , a first inorganic layer  181  is formed on the light-shielding structures  136  and the first planarization layer  171 . Via-holes are provided in such a manner as to penetrate through the first inorganic layer  181  at target regions, and an orthogonal projection of each via-hole onto the second substrate  140  is located within an orthogonal projection of the corresponding light-shielding structure  136  onto the second substrate  140 . 
     Next, the optical sensors  133  are formed at a side of the first inorganic layer  181  away from the second substrate  140 , and each optical sensor  133  is arranged close to the corresponding target region, as shown in  FIG.  6   . The supporting structures  135  are formed at the target regions, and each supporting structure  135  covers the corresponding via-hole. A height of each supporting structure  135  in a direction perpendicular to the second substrate  140  is larger than a height of the optical sensor  133  in the direction perpendicular to the second substrate  140 . A second inorganic layer  182  covering the optical sensors  133  and the supporting structures  135  is formed, as shown in  FIG.  6     c.    
     Next, a second planarization layer  172  covering the optical sensors  133 , the supporting structures  135 , the first inorganic layer  181  and the second inorganic layer  182  is formed on the second substrate  140 , black matrices  134  are formed on the second planarization layer  172 , and the orthogonal projection of each supporting structure  135  onto the second substrate  140  is located within an orthogonal projection of a corresponding black matrix  134  onto the second substrate  140 , as shown in  FIG.  6     d.    
     Next, quantum dot light-emitting units  131  in different colors are formed in gaps between the black matrices  134 , as shown in  FIG.  6   e   , and an orthogonal projection of each quantum dot light-emitting unit  131  onto the first substrate  120  partially overlaps the orthogonal projection of the corresponding optical sensor  133  onto the first substrate  120 . 
     In addition, after the formation of the quantum dot light-emitting units  131  of the quantum dot module  130 , a third inorganic layer  183  covering the black matrices  134  and the quantum dot light-emitting units  131  is further formed, and the color filter layers  132  spaced apart from each other and black matrices each between adjacent color filter layers  132  are formed on the third inorganic layer  183 . 
     Further, the forming the quantum dot module on the second substrate includes: forming the black matrices and the quantum dot light-emitting units each located between two adjacent black matrices on the second substrate; providing a third substrate, and forming the light-shielding structures on the third substrate; forming the optical sensor and the supporting structure at a side of each light-shielding structure away from the third substrate, an orthogonal projection of the optical sensor onto the third substrate and an orthogonal projection of the supporting structure onto the third substrate not overlapping each other and being located in an orthogonal projection of the light-shielding structure onto the third substrate; and encapsulating the third substrate at a side of the quantum dot light-emitting units away from the second substrate. The optical sensor, the supporting structure and the light-shielding structure are located between the third substrate and the second substrate, and an orthogonal projection of each quantum dot light-emitting unit onto the second substrate partially overlaps the orthogonal projection of the corresponding optical sensor onto the second substrate. 
     In the embodiments of the present disclosure, as shown in  FIG.  7   a   , the black matrices  134  are formed on the second substrate  140 , and then the quantum dot light-emitting units  131  in different colors are formed in the gaps between the black matrices  134 . After the formation of the quantum dot light-emitting units  131 , a fourth inorganic layer  184  covering the black matrices  134  and the quantum dot light-emitting units  131  is formed, and the color filter layers  132  spaced apart from each other and black matrices each between adjacent color filter layers  132  are formed on the fourth inorganic layer  184 . 
     In the embodiments of the present disclosure, as shown in  FIG.  7   b   , the light-shielding structures  136  are formed on the third substrate  160 . After the formation of the light-shielding structures  136 , a third planarization layer  173  is formed. A surface of the third planarization layer  173  away from the third substrate  160  is flush with a surface of each light-shielding structure  136  away from the third substrate  160 . After the formation of the third planarization layer  173 , a fifth inorganic layer  185  is formed on the light-shielding structures  136  and the third planarization layer  173 . Second via-holes are provided in such a manner as to penetrate through the fifth inorganic layer  185  at second target regions, and an orthogonal projection of each second via-hole onto the third substrate  160  is located within the orthogonal projection of the corresponding light-shielding structure  136  onto the third substrate  160 . 
     Next, the optical sensors  133  are formed at a side of the fifth inorganic layer  185  away from the third substrate  160 , and each optical sensor  133  is arranged close to the corresponding second target region, as shown in  FIG.  7   b   . The supporting structures  135  are formed at the second target regions, and each supporting structure  135  covers the corresponding second via-hole. A height of each supporting structure  135  in the direction perpendicular to the third substrate  160  is larger than a height of the optical sensor  133  in the direction perpendicular to the third substrate  160 . A sixth inorganic layer  186  covering the optical sensors  133  and the supporting structures  135  is formed, as shown in  FIG.  7     b.    
     The present disclosure further provides in some embodiments a display device, including the above-mentioned display panel. 
     The display device is a monitor, a mobile phone, a tablet personal computer, a television, a wearable electronic device, a navigation display device, etc. 
     Unless otherwise defined, any technical or scientific term used herein shall have the common meaning understood by a person of ordinary skills. Such words as “first” and “second” used in the specification and claims are merely used to differentiate different components rather than to represent any order, number or importance. Similarly, such words as “one” or “one of” are merely used to represent the existence of at least one member, rather than to limit the number thereof. Such words as “include” or “including” intends to indicate that an element or object before the word contains an element or object or equivalents thereof listed after the word, without excluding any other element or object. Such words as “connect/connected to” or “couple/coupled to” may include electrical connection, direct or indirect, rather than to be limited to physical or mechanical connection. Such words as “on”, “under”, “left” and “right” are merely used to represent relative position relationship, and when an absolute position of the object is changed, the relative position relationship will be changed too. 
     It should be appreciated that, in the case that such an element as layer, film, region or substrate is arranged “on” or “under” another element, it may be directly arranged “on” or “under” the other element, or an intermediate element may be arranged therebetween. 
     The above embodiments are for illustrative purposes only, but the present disclosure is not limited thereto. Obviously, a person skilled in the art may make further modifications and improvements without departing from the spirit of the present disclosure, and these modifications and improvements shall also fall within the scope of the present disclosure.