Patent Publication Number: US-2023157139-A1

Title: Organic light-emitting diode display panel

Description:
BACKGROUND OF INVENTION 
     Field of Invention 
     The present application relates to the field of display technology, and in particular to an organic light-emitting diode (OLED) display panel. 
     Description of Prior Art 
     OLED displays have a wide range of advantages, such as high color gamut, good viewing angles, and fast response times. However, OLED displays also have some shortcomings of their own. For example, OLED displays have lower brightness and poorer stability than other displays. 
     On the other hand, for an organic light-emitting diode (OLED) display based on an inkjet printing process, there is a risk of color shift at certain viewing angles, due to a microcavity effect of organic light-emitting monomers of red/green/blue sub-pixels of the OLED display. In order to improve the viewing angles and brightness of the OLED, many improvement methods have been proposed. For example, adding optical microstructures (such as microlens arrays, gratings, etc.) on a light-exiting surface, or adding a refractive index matching layer between light-exiting interfaces. These methods have a certain effect, but feasibility of mass production is not high. 
     In one technology, a solution for adding scattering particles to a thin film encapsulation (TFE) layer is proposed. This solution has its own unique advantages, such as simple manufacturing process, no need for patterning, and controllable particles. However, there are also problems. A tetrafluoroethylene layer is a functional layer that acts as thin film encapsulation to insulate water and oxygen. When the scattering particles are mixed, portions of the TFE layer may penetrate up and down locally due to uneven dispersion or other reasons, which impacts encapsulation effect. On the other hand, due to strong reflection of the OLED display, it is necessary to attach a circular polarizer to a surface of the OLED display, thereby greatly reducing the reflectivity of ambient light. However, the circular polarizer will cause an efficiency of emitted light to be reduced by more than 50%, which is a key factor of affecting brightness of the OLED display device. Meanwhile, a thickness of the circular polarizer itself is often more than 100 microns, and it is attached to an outer side of the OLED display device, which is not conducive to curling, flexibility, and folding functions of the OLED display device. 
     In order to resolve the above problems, the industry has begun to use RGB color filters combined with a thin anti-reflective (AR) film to remove a polarizing film. However, because an anode of the OLED display has a very strong reflectivity, the color filters cannot completely filter out reflected light from the anode, resulting in a reflectivity maintained at about 10%. Such reflectivity will exhibit a poor visual effect even in places where the ambient light is slightly strong. 
     Referring to  FIG.  1   .  FIG.  1    is a schematic diagram of a structure of an organic light-emitting diode (OLED) display panel in the prior art. As shown in  FIG.  1   , since a light transmittance of a color filter layer  100  is generally high, when the color filter layer  100  is used to reduce the reflected light, the effect of reducing the reflected light that can be achieved depends on a degree of light absorption of the color filter layer  100 . Further, referring to  FIG.  2   ,  FIG.  2    is a spectrum diagram of the transmitted light of the color filter layer in the prior art. As shown in  FIG.  2   , light transmittance of the color filter layer  100  at peaks of a green light band, a blue light band, and a red light band is above 80%, so round-trip transmission of reflected light can be simply calculated as T=0.8*0.8*anode reflection. which is still very large. 
     Therefore, the existing technology has shortcomings and urgently needs improvement. 
     SUMMARY OF INVENTION 
     An object of embodiments of the present application is to provide an organic light-emitting diode (OLED) display panel, wherein by adopting a light-absorbing material layer in a light-exiting direction of the organic light-emitting layer to filter out reflected light of an anode metal layer of the organic light-emitting layer, a poor visual effect can be prevented even in places where ambient light is slightly strong, thereby improving user&#39;s experience. 
     An embodiment of the present application provides an organic light-emitting diode (OLED) display panel, which includes: 
     a substrate; 
     an organic light-emitting layer disposed on the substrate, and provided with a plurality of organic light-emitting monomers; 
     a color filter layer disposed on a side of the organic light-emitting layer facing toward a light-exiting direction; and 
     a light-absorbing material layer disposed on the side of the organic light-emitting layer facing toward a light-exiting direction. 
     In the OLED display panel described in an embodiment of the present application, the organic light-emitting layer includes a cathode metal layer, an anode metal layer, and a light-emitting layer located between the cathode metal layer and the anode metal layer; the light-emitting layer is formed of the plurality of organic light-emitting monomers; and the light-emitting layer emits light toward a side away from the substrate; and 
     wherein the color filter layer is disposed on a side of the cathode metal layer away from the substrate, and the light-absorbing material layer is disposed on a side of the color filter layer away from the substrate. 
     In the OLED display panel described in an embodiment of the present application, the organic light-emitting layer includes a cathode metal layer, an anode metal layer, and a light-emitting layer located between the cathode metal layer and the anode metal layer; the light-emitting layer is formed of the plurality of organic light-emitting monomers; and the light-emitting layer emits light toward a side close to the substrate; and 
     wherein the color filter layer is disposed on a side of the anode metal layer close to the substrate, and the light-absorbing material layer is disposed on a side of the color filter layer close to the substrate. 
     In the OLED display panel described in an embodiment of the present application, the light-absorbing material layer includes a plurality of pixel areas corresponding to the plurality of organic light-emitting monomers; and 
     a thickness of the light-absorbing material layer in the pixel areas is 50 nanometers to 2000 nanometers. 
     In the OLED display panel described in an embodiment of the present application, the light-absorbing material layer includes a plurality of pixel areas corresponding to the plurality of organic light-emitting monomers; and 
     an absorbance of the light-absorbing material layer in the pixel areas for light with a wavelength of 380 nanometers to 700 nanometers is less than 95%. 
     In the OLED display panel described in an embodiment of the present application, the light-absorbing material layer includes a plurality of pixel areas corresponding to the plurality of organic light-emitting monomers; and the light-absorbing material layer further includes non-pixel areas corresponding to spacer areas of the plurality of organic light-emitting monomers; and 
     an absorbance of the non-pixel areas is greater than an absorbance of the pixel areas. 
     In the OLED display panel described in an embodiment of the present application, the light-absorbing material layer includes a plurality of pixel areas corresponding to the plurality of organic light-emitting monomers; the light-absorbing material layer further includes non-pixel areas corresponding to spacer areas of the plurality of organic light-emitting monomers; and the substrate includes a first substrate area and a second substrate area; 
     wherein the color filter layer includes a first color filter area and a second color filter area; and 
     wherein the first color filter area corresponds to the second substrate area, the second color filter area corresponds to the first substrate area, and the pixel areas and the non-pixel areas correspond to the first substrate area. 
     In the OLED display panel described in an embodiment of the present application, the light-absorbing material layer further includes a first area, and the first area corresponds to the first color filter area. 
     In the OLED display panel described in an embodiment of the present application, an absorbance of the light-absorbing material layer in the first area is greater than or equal to an absorbance of the light-absorbing material layer in the non-pixel areas. 
     In the OLED display panel described in an embodiment of the present application, a thickness of the light-absorbing material layer in the non-pixel areas is greater than a thickness of the light-absorbing material layer in the pixel areas. 
     In the OLED display panel described in an embodiment of the present application, the non-pixel areas protrude from the pixel areas to form a plurality of pixel holes on a side of the light-absorbing material layer facing away from the light exiting direction, and each of the pixel holes is provided with the organic light-emitting monomers. 
     In the OLED display panel described in an embodiment of the present application, the non-pixel areas are coated with a light-shielding material layer. 
     Another embodiment of the present application also provides an organic light-emitting diode (OLED) display panel, which includes: 
     a substrate; 
     an organic light-emitting layer disposed on the substrate, and provided with a plurality of organic light-emitting monomers; 
     a color filter layer disposed on a side of the organic light-emitting layer facing toward a light-exiting direction; 
     a light-absorbing material layer disposed on the side of the organic light-emitting layer facing toward a light-exiting direction, 
     wherein the light-absorbing material layer includes a plurality of pixel areas corresponding to the plurality of organic light-emitting monomers; 
     a thickness of the light-absorbing material layer in the pixel areas is 50 nanometers to 2000 nanometers; and 
     an absorbance of the light-absorbing material layer in the pixel areas for light with a wavelength of 380 nanometers to 700 nanometers is less than 95%. 
     In the OLED display panel described in an embodiment of the present application, the organic light-emitting layer includes a cathode metal layer, an anode metal layer, and a light-emitting layer located between the cathode metal layer and the anode metal layer; the light-emitting layer is formed of the plurality of organic light-emitting monomers; and the light-emitting layer emits light toward a side away from the substrate; and 
     wherein the color filter layer is disposed on a side of the cathode metal layer away from the substrate, and the light-absorbing material layer is disposed on a side of the color filter layer away from the substrate. 
     In the OLED display panel described in an embodiment of the present application, the organic light-emitting layer includes a cathode metal layer, an anode metal layer, and a light-emitting layer located between the cathode metal layer and the anode metal layer; the light-emitting layer is formed of the plurality of organic light-emitting monomers; and the light-emitting layer emits light toward a side close to the substrate; and 
     wherein the color filter layer is disposed on a side of the anode metal layer close to the substrate, and the light-absorbing material layer is disposed on a side of the color filter layer close to the substrate. 
     In the OLED display panel described in an embodiment of the present application, the light-absorbing material layer includes a plurality of pixel areas corresponding to the plurality of organic light-emitting monomers; and the light-absorbing material layer further includes non-pixel areas corresponding to spacer areas of the plurality of organic light-emitting monomers; and 
     an absorbance of the non-pixel areas is greater than an absorbance of the pixel areas. 
     In the OLED display panel described in an embodiment of the present application, the light-absorbing material layer includes a plurality of pixel areas corresponding to the plurality of organic light-emitting monomers; the light-absorbing material layer further includes non-pixel areas corresponding to spacer areas of the plurality of organic light-emitting monomers; and the substrate includes a first substrate area and a second substrate area; 
     wherein the color filter layer includes a first color filter area and a second color filter area; and 
     wherein the first color filter area corresponds to the second substrate area, the second color filter area corresponds to the first substrate area, and the pixel areas and the non-pixel areas correspond to the first substrate area. 
     In the OLED display panel described in an embodiment of the present application, the light-absorbing material layer further includes a first area, and the first area corresponds to the first color filter area. 
     In the OLED display panel described in an embodiment of the present application, an absorbance of the light-absorbing material layer in the first area is greater than or equal to an absorbance of the light-absorbing material layer in the non-pixel areas. 
     In the OLED display panel described in an embodiment of the present application, a thickness of the light-absorbing material layer in the non-pixel areas is greater than a thickness of the light-absorbing material layer in the pixel areas. 
     In view of above, in the OLED display panel and the OLED display device provided by the embodiments of the present application, by adopting a light-absorbing material layer in a light-exiting direction of the organic light-emitting layer to filter out reflected light of an anode metal layer of the organic light-emitting layer, a poor visual effect can be prevented even in places where ambient light is slightly strong, thereby improving user&#39;s experience. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The following describes the specific implementations of the present application in detail with reference to the accompanying drawings, which will make the technical solutions and other beneficial effects of the present application obvious. 
         FIG.  1    is a schematic diagram of a structure of an organic light-emitting diode (OLED) display panel in the prior art. 
         FIG.  2    is a spectrum diagram of transmitted light of a color filter layer in the prior art. 
         FIG.  3    is a schematic diagram of a first structure of an organic light-emitting diode (OLED) display panel in an embodiment of the present application. 
         FIG.  4    is a schematic diagram of a second structure of the OLED display panel in an embodiment of the present application. 
         FIG.  5    is a schematic diagram of a third structure of the OLED display panel in an embodiment of the present application. 
         FIG.  6    is a schematic diagram of a fourth structure of the OLED display panel in an embodiment of the present application. 
         FIG.  7    is a schematic diagram of a fifth structure of the OLED display panel in an embodiment of the present application. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. 
     The present application provides an organic light-emitting diode (OLED) display panel, including: a substrate; an organic light-emitting layer disposed on the substrate, and provided with a plurality of organic light-emitting monomers; a color filter layer disposed on a side of the organic light-emitting layer facing toward a light-exiting direction; and a light-absorbing material layer disposed on the side of the organic light-emitting layer facing toward a light-exiting direction. In the present application, by adopting a light-absorbing material layer in a light-exiting direction of the organic light-emitting layer to filter out reflected light of an anode metal layer of the organic light-emitting layer, a poor visual effect can be prevented even in places where ambient light is slightly strong, thereby improving user&#39;s experience. 
     Referring to  FIG.  1    in conjunction with  FIG.  2   , a light-absorbing material layer is employed to coat a color filter layer to achieve further absorption of reflected light. Since the color filter layer  100  itself has excellent light transmission performance for green light, blue light, and red light emitted by the organic light-emitting layer  200  and the organic light-emitting layer  300 , after removing a polarizing film and adding the color filter, luminous brightness of an organic light-emitting diode (OLED) display panel will be increased by more than 60%, so that there is a sufficient level of brightness to use a light-absorbing material that absorbs all visible light bands. 
     Referring to  FIG.  3   ,  FIG.  3    is a schematic diagram of a first structure of an organic light-emitting diode (OLED) display panel in an embodiment of the present application. As shown in  FIG.  3   , the OLED display panel includes: a substrate  10 , an organic light-emitting layer  20 , a light-absorbing material layer  30 , and a color filter layer  40 . 
     The OLED display panel in an embodiment of the present application is a bottom light-emitting type OLED display panel. That is, the OLED display panel of an embodiment of the present application emits light toward a side close to the substrate  10 . Specifically, the organic light-emitting layer  20  is disposed on the substrate  10 ; the color filter layer  40  is disposed in a light-exiting direction of the organic light-emitting layer  20 ; and the light-absorbing material layer  30  is disposed in the light-exiting direction of the organic light-emitting layer  20 . In an embodiment of the present application, the substrate  10 , the light-absorbing material layer  30 , the color filter layer  40 , and the organic light-emitting layer  20  are stacked in sequence. 
     Specifically, the substrate  10  includes a substrate body and a TFT array layer disposed on the substrate body. The substrate body may be a transparent glass substrate or a transparent PV material substrate. The organic light-emitting layer  20  has a same structure as the organic light-emitting layer in the prior art, and includes an anode metal layer, an electron injection layer, an electron transport layer, a light-emitting layer, a hole transport layer, a hole injection layer, and a cathode metal layer, which belong to the prior art, and details will not be described herein for brevity. The color filter layer  40  may be a quantum dot color filter layer. In some embodiments, the color filter layer  40  may also be a conventional color filter layer. 
     In some embodiments, referring to  FIG.  4   ,  FIG.  4    is a schematic diagram of a second structure of an organic light-emitting diode (OLED) display panel in an embodiment of the present application. As shown in  FIG.  4   , the substrate  10  includes a first substrate area  11  and a second substrate area  12 . The light-absorbing material layer  30  includes pixel areas  31 , non-pixel areas  32 , and a first area. The color filter layer  40  includes a first color filter area  41  and a second color filter area  42 . 
     The light-emitting layer includes a plurality of organic light-emitting monomers distributed in an array at intervals. The plurality of organic light-emitting monomers include blue organic light-emitting monomers  20   a , green organic light-emitting monomers  20   b , and red organic light-emitting monomers  20   c.    
     It should be noted that the organic light-emitting layer  20  includes a cathode metal layer, an anode metal layer, and a light-emitting layer located between the cathode metal layer and the anode metal layer; the light-emitting layer is formed of a plurality of organic light-emitting monomers; and the light-emitting layer faces away from the substrate, wherein the color filter layer is arranged on a side of the cathode metal layer away from the substrate, and the light-absorbing material layer is arranged on the side of the color filter layer away from the substrate. 
     The plurality of pixel areas  31  are arranged corresponding to the plurality of organic light-emitting monomers. The non-pixel areas  32  are arranged corresponding to spacer areas of the plurality of organic light-emitting monomers. The first color filter area  41  is disposed corresponding to the second substrate area  12  of the substrate  10  and the first area  33  of the light-absorbing material layer  30 . That is, the first color filter area  41  is arranged corresponding to the TFT array layer for shielding thin film transistors and metal traces of the TFT array layer. The second color filter area  42  is arranged corresponding to the first substrate area of the substrate. The pixel areas  31  and the non-pixel areas  32  are arranged corresponding to the first substrate area of the substrate. 
     Specifically, a thickness of the light-absorbing material layer  30  in the pixel area  31  is 50 nanometers to 2000 nanometers. A light absorbance of the light-absorbing material layer in the pixel areas for light with a wavelength of 380 nanometers to 700 nanometers is less than 95%. In addition, the light absorbance of the light-absorbing material layer  30  in the pixel areas is lower than the light absorbance of the light-absorbing material layer  30  in the non-pixel area, so as to better absorb light reflected by the metal traces in the space areas. 
     Of course, there are many ways to realize the light absorbance of the light-absorbing material layer in the pixel areas  31  being lower than the light absorbance of the light-absorbing material layer in the non-pixel area. In some embodiments, the thickness of the pixel areas  31  is less than the thickness of the non-pixel area. In some embodiments, the non-pixel areas  32  are coated with a light-shielding material layer. Alternatively, in some embodiments, the thickness of the pixel areas  31  is less than the thickness of the non-pixel area, and the non-pixel areas  32  are coated with a light-shielding material layer. 
     In some embodiments, referring to  FIG.  5   ,  FIG.  5    is a schematic diagram of a third structure of an organic light-emitting diode (OLED) display panel in an embodiment of the present application. As shown in  FIG.  5   , a thickness of pixel areas  31  is less than a thickness of non-pixel areas  32 . Specifically, on the side of the light-absorbing material layer  30  facing away from the light-exiting direction, that is, on the side away from the substrate  10 , the non-pixel areas  32  protrude from the pixel areas  31  to form a plurality of pixel holes, and each of the pixel holes is provided with the organic light-emitting monomers. The plurality of organic light-emitting monomers of the organic light-emitting layer include blue organic light-emitting monomers  20   a , green organic light-emitting monomers  20   b , and red organic light-emitting monomers  20   c . Specifically, in the manufacturing process, the pixel areas are thinned by a photolithography process to obtain a plurality of pixel holes, so that there is no need to provide a black matrix, which can reduce the process steps, improve efficiency, and reduce costs. 
     Of course, it is appreciated that in some embodiments, the non-pixel areas  32  can also be coated with a light-shielding material layer to increase light absorbance of the non-pixel areas. 
     In view of above, in the OLED display panel and the OLED display device provided by the embodiments of the present application, by adopting a light-absorbing material layer in a light-exiting direction of the organic light-emitting layer to filter out reflected light of an anode metal layer of the organic light-emitting layer, a poor visual effect can be prevented even in places where ambient light is slightly strong, thereby improving user&#39;s experience. 
     Referring to  FIG.  6   ,  FIG.  6    is a schematic diagram of a fourth structure of an organic light-emitting diode (OLED) display panel in an embodiment of the present application. The OLED display panel includes a substrate  10 , an organic light-emitting layer  20 , a light-absorbing material layer  30 , and a color filter layer  40 . 
     The OLED display panel in this embodiment is a top light-emitting OLED display panel. That is, the OLED display panel of an embodiment of the present application emits light toward a side away from the substrate  10 . Specifically, the organic light-emitting layer is arranged on the substrate; the color filter layer is arranged in a light-exiting direction of the organic light-emitting layer; and the light-absorbing material layer is arranged in the light-exiting direction of the organic light-emitting layer. In an embodiment of the present application, the substrate  10 , the organic light-emitting layer  20 , the color filter layer  40 , and the light-absorbing material layer  30  are stacked in sequence. 
     Specifically, the substrate  10  includes a substrate body and a TFT array layer disposed on the substrate body. The substrate body may be a transparent glass substrate or a transparent PV material substrate. The organic light-emitting layer  20  has a same structure as the organic light-emitting layer in the prior art, and includes an anode metal layer, an electron injection layer, an electron transport layer, a light-emitting layer, a hole transport layer, a hole injection layer, and a cathode metal layer, which belong to the prior art, and details will not be described herein for brevity. The color filter layer  40  may be a quantum dot color filter layer. In some embodiments, the color filter layer  40  may also be a conventional color filter layer. 
     In some embodiments, referring to  FIG.  7   ,  FIG.  7    is a schematic diagram of a fifth structure of the OLED display panel in the embodiments of the present application. As shown in  FIG.  7   , the substrate  10  includes a first substrate area  11  and a second substrate area  12 . The light-absorbing material layer  30  includes pixel areas  31 , pixel areas  32 , and a first area. The color filter layer  40  includes a first color filter area  41  and a second color filter area  42 . 
     The light-emitting layer includes a plurality of organic light-emitting monomers distributed in an array at intervals. The plurality of organic light-emitting monomers include blue organic light-emitting monomers  20   a , green organic light-emitting monomers  20   b , and red organic light-emitting monomers  20   c.    
     It should be noted that the organic light-emitting layer  20  includes a cathode metal layer, an anode metal layer, and a light-emitting layer located between the cathode metal layer and the anode metal layer; the light-emitting layer is formed of a plurality of organic light-emitting monomers; and the light-emitting layer faces away from the substrate, wherein the color filter layer is arranged on a side of the cathode metal layer away from the substrate, and the light-absorbing material layer is arranged on the side of the color filter layer away from the substrate. 
     The plurality of pixel areas  31  are arranged corresponding to the plurality of organic light-emitting monomers. The non-pixel areas  32  are arranged corresponding to spacer areas of the plurality of organic light-emitting monomers. The first color filter area  41  is disposed corresponding to the second substrate area  12  of the substrate  10  and the first area  33  of the light-absorbing material layer  30 . That is, the first color filter area  41  is arranged corresponding to the TFT array layer for shielding thin film transistors and metal traces of the TFT array layer. The second color filter area  42  is arranged corresponding to the first substrate area of the substrate. The pixel areas  31  and the non-pixel areas  32  are arranged corresponding to the first substrate area of the substrate. 
     Specifically, a thickness of the light-absorbing material layer  30  in the pixel area  31  is 50 nanometers to 2000 nanometers. A light absorbance of the light-absorbing material layer in the pixel areas for light with a wavelength of 380 nanometers to 700 nanometers is less than 95%. In addition, the light absorbance of the light-absorbing material layer  30  in the pixel areas is lower than the light absorbance of the light-absorbing material layer  30  in the non-pixel area, so as to better absorb light reflected by the metal traces in the space areas. 
     Of course, there are many ways to realize the light absorbance of the light-absorbing material layer in the pixel areas  31  being lower than the light absorbance of the light-absorbing material layer in the non-pixel area. In some embodiments, the thickness of the pixel areas  31  is less than the thickness of the non-pixel area. In some embodiments, the non-pixel areas  32  are coated with a light-shielding material layer. Alternatively, in some embodiments, the thickness of the pixel areas  31  is less than the thickness of the non-pixel area, and the non-pixel areas  32  are coated with a light-shielding material layer. 
     Further, a thickness of pixel areas  31  is less than a thickness of non-pixel areas  32 . Specifically, on the side of the light-absorbing material layer  30  facing away from the light-exiting direction, that is, on the side away from the substrate  10 , the non-pixel areas  32  protrude from the pixel areas  31  to form a plurality of pixel holes, and each of the pixel holes is provided with the organic light-emitting monomers. The plurality of organic light-emitting monomers of the organic light-emitting layer include blue organic light-emitting monomers  20   a , green organic light-emitting monomers  20   b , and red organic light-emitting monomers  20   c . Specifically, in the manufacturing process, the pixel areas are thinned by a photolithography process to obtain a plurality of pixel holes, so that there is no need to provide a black matrix, which can reduce the process steps, improve efficiency, and reduce costs. 
     Of course, it is appreciated that in some embodiments, the non-pixel areas  32  can also be coated with a light-shielding material layer to increase light absorbance of the non-pixel areas. 
     In view of above, in the OLED display panel and the OLED display device provided by the embodiments of the present application, by adopting a light-absorbing material layer in a light-exiting direction of the organic light-emitting layer to filter out reflected light of an anode metal layer of the organic light-emitting layer, a poor visual effect can be prevented even in places where ambient light is slightly strong, thereby improving user&#39;s experience. 
     The above descriptions are only examples of the present application and are not used to limit the protection scope of the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.