Patent Publication Number: US-2023140663-A1

Title: Display panel and display device

Description:
FIELD OF DISCLOSURE 
     The present invention relates to a field of display technology and in particular, to a display panel and a display device. 
     DESCRIPTION OF RELATED ART 
     Organic light-emitting diode (OLED) displays are self-luminous display devices, because they can use organic light-emitting materials to self-luminate under an applied voltage, without a need for an additional backlight. Therefore, the OLED displays have advantages such as being light and thin. In addition, because organic materials are flexible and easy to bend, the OLED displays can be made into flexible and foldable displays. Therefore, the OLED displays are more extensively used in the display field. 
     At present, due to the flexible and easy bending characteristics of OLED displays, manufacturers have launched many products such as “curved screens”, “surround screens”, and “waterfall screens” to further increase a screen ratio and enhance display effects. However, the “surround screen” and “waterfall screen” are bent a large angle at left and right ends of a display, so that when viewing an image vertically with respect to the display, due to the large viewing angle, displayed images in curved display regions at the left and right ends of the display inevitably have color shift problems such as “green edges” and other undesirable color shift problems known on the market. 
     In summary, it is necessary to provide a new display panel and a display device to solve the above technical problems. 
     SUMMARY 
     The display panel and the display device provided by the present invention solve a problem of conventional display panels and display devices. The problem is that, different color lights emitted by an organic light-emitting layer have different changes in brightness and chromaticity at different viewing angles, so images displayed at a bent portion of the display panel easily have larger color shifts at large viewing angles. 
     To solve the above problem, the present invention provides a technical solution as follows. 
     The present invention provides a display panel, comprising a flat display region and a curved display region located on at least one side of the flat display region, wherein the display panel further comprises: 
     an array substrate; 
     a pixel definition layer disposed on the array substrate, wherein the pixel definition layer defines a plurality of pixel definition openings; 
     an organic light-emitting layer disposed in the pixel definition opening and configured to emit various color lights; 
     a cathode layer disposed on the pixel definition layer and the organic light-emitting layer; 
     an encapsulation layer disposed on the cathode layer; and 
     an absorption layer disposed on one side of the pixel definition layer away from the array substrate, wherein the absorption layer comprises a red light absorber coating, a green light absorber coating, or a blue light absorber coating, the absorption layer is disposed corresponding to at least a portion of the pixel definition layer in the curved display region for selectively absorbing at least one color light emitted by the organic light emitting layer disposed in the curved display region. 
     In the display panel according to one embodiment of the present invention, the absorption layer is disposed between the pixel-definition layer and the cathode layer. 
     In the display panel according to one embodiment of the present invention, the absorption layer is disposed between the cathode layer and the encapsulation layer. 
     In the display panel according to one embodiment of the present invention, the absorption layer is disposed on the encapsulation layer. 
     In the display panel according to one embodiment of the present invention, the encapsulation layer comprises a first inorganic encapsulation layer, an organic encapsulation layer, and a second inorganic encapsulation layer sequentially stacked on the cathode layer, and the absorption layer is disposed inside the encapsulation layer. 
     In the display panel according to one embodiment of the present invention, a thickness of the first inorganic encapsulation layer and a thickness of the second inorganic encapsulation layer range from 1 nm to 10 μm, and a thickness of the organic encapsulation layer ranges from 10 nm to 20 μm. 
     In the display panel according to one embodiment of the present invention, the plurality of color lights emitted by the organic light-emitting layer at least comprise a first color light, a second color light, and a third color light; in a vertical viewing angle, a brightness ratio of the first color light in the flat display region to the first color light in the curved display region is greater than a brightness ratio of the second color light in the flat display region to the second color light in the curved display region, and the brightness ratio of the second color light in the flat display region to the second color light in the curved display region is equal to a brightness ratio of the third color light in the flat display region to the third color light in the curved display region; and the absorption layer absorbs at least a portion of the first color light. 
     In the display panel according to one embodiment of the present invention, the first color light, the second color light, and the third color light are red light, green light, and blue light in any sequence; and the first color light, the second color light, and the third color light are different colors. 
     In the display panel according to one embodiment of the present invention, the curved display regions are located at opposite two sides of the flat display region, and each of the curved display regions is bent in a direction away from a display direction of the display panel. 
     In the display panel according to one embodiment of the present invention, a thickness of the absorption layer ranges from 0.01 μm to 10 μm. 
     The present invention provides a display panel comprising a flat display region and a curved display region located on at least one side of the flat display region, wherein the display panel further comprises: 
     an array substrate; 
     a pixel definition layer disposed on the array substrate, wherein the pixel definition layer defines a plurality of pixel definition openings; 
     an organic light-emitting layer disposed in the pixel definition opening and configured to emit various color lights; 
     a cathode layer disposed on the pixel definition layer and the organic light-emitting layer; 
     an encapsulation layer disposed on the cathode layer; and 
     an absorption layer disposed on one side of the pixel definition layer away from the array substrate, wherein the absorption layer is disposed corresponding to at least a portion of the pixel definition layer in the curved display region for selectively absorbing at least one color light emitted by the organic light emitting layer disposed in the curved display region. 
     In the display panel according to one embodiment of the present invention, the absorption layer is disposed between the pixel definition layer and the cathode layer. 
     In the display panel according to one embodiment of the present invention, the absorption layer is disposed between the cathode layer and the encapsulation layer. 
     In the display panel according to one embodiment of the present invention, the absorption layer is disposed on the encapsulation layer. 
     In the display panel according to one embodiment of the present invention, the encapsulation layer comprises a first inorganic encapsulation layer, an organic encapsulation layer, and a second inorganic encapsulation layer sequentially stacked on the cathode layer, and the absorption layer is disposed inside the encapsulation layer. 
     In the display panel according to one embodiment of the present invention, the absorption layer is arranged between the first inorganic encapsulation layer and the organic encapsulation layer. 
     In the display panel according to one embodiment of the present invention, the absorption layer is arranged between the organic encapsulation layer and the second inorganic encapsulation layer. 
     In the display panel according to one embodiment of the present invention, the plurality of color lights emitted by the organic light emitting layer at least comprise a first color light, a second color light, and a third color light; in a vertical viewing angle, a brightness ratio of the first color light in the flat display region to the first color light in the curved display region is greater than a brightness ratio of the second color light in the flat display region to the second color light in the curved display region, and the brightness ratio of the second color light in the flat display region to the second color light in the curved display region is equal to a brightness ratio of the third color light in the flat display region to the third color light in the curved display region; and the absorption layer absorbs at least a portion of the first color light. 
     In the display panel according to one embodiment of the present invention, the first color light, the second color light, and the third color light are red light, green light, and blue light in any sequence; and the first color light, the second color light, and the third color light are different colors. 
     The present invention provides a display device which comprises the display panel mentioned above. 
     In the display panel and the display device of the present invention, by providing the absorption layer corresponding to at least a portion of the pixel definition layer located in the curved display region, at least one color light emitted by the organic light-emitting layer located in the curved display region is selectively absorbed, so as to adjust the brightness ratios of the various color lights emitted by the organic light-emitting layer at large viewing angles, and reduce the risk of color shift in a white screen at large viewing angles. At the same time, the absorption layer has no absorption and interference effects on the light emitted in a forward (vertical) direction by the organic light-emitting layer at the vertical viewing angle, so that this configuration does not cause color shift of images at a vertical viewing angle, and the display performance of the display panel is improved. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       In order to more clearly illustrate the embodiments of the present disclosure or related art, figures which will be described in the embodiments are briefly introduced hereinafter. It is obvious that the drawings are merely for the purposes of illustrating some embodiments of the present disclosure, and a person having ordinary skill in this field can obtain other figures according to these figures without inventive work. 
         FIG.  1    is a schematic plan view illustrating a display panel according to one embodiment of the present application; 
         FIG.  2    is a schematic cross-sectional view illustrating the display panel according to one embodiment of the present invention; 
         FIG.  3    is a schematic cross-sectional view illustrating a structure of the display panel in a curved display region according to a first embodiment of the present invention; 
         FIG.  4    is a schematic cross-sectional view illustrating the structure of the display panel in the curved display region according to a second embodiment of the present invention; 
         FIG.  5    is a schematic cross-sectional view illustrating the structure of the display panel in the curved display region according to a third embodiment of the present invention; 
         FIG.  6    is a schematic cross-sectional view illustrating the structure of the display panel in the curved display region according to a fourth embodiment of the present invention; and 
         FIG.  7    is a schematic cross-sectional view illustrating the structure of the display panel in the curved display region according to a fifth embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     A description is provided below with reference to the accompanying drawings to illustrate specific embodiments of the present invention. The directional terms mentioned in the present invention, such as “upper”, “lower”, “front”, “rear”, “left”, “right”, “inner”, “outer”, and “lateral”, are for illustrative purposes based on the accompanying drawings. Therefore, the directional terms are only used to describe and understand the present invention, rather than to limit the present invention. In the drawings, structurally similar elements are indicated by the same reference numerals. 
     The present invention is directed to solving a problem of conventional display panels and display devices. The problem is that, different color lights emitted by an organic light-emitting layer have different changes in brightness and chromaticity at different viewing angles, so images displayed in a bent portion of the display panel easily have larger color shifts at large viewing angles. The present invention can solve this defect. 
     Please refer to  FIGS.  1  and  2   , showing a display panel according to one embodiment of the present invention. The display panel comprises a flat display region  100  and a curved display region  200  located on at least one side of the flat display region  100 . The present embodiment does not limit a positional relationship between the flat display region  100  and the curved display region  200 . The curved display region  200  can be arranged on one or more sides of the flat display region  100 , so as to form, for example, a “curved screen” or a “waterfall screen”. The curved display region  200  can also surround the flat display region  100 , so as to form, for example, a “surround screen”. In the display panel shown in  FIGS.  1  and  2   , the curved display regions  200  are located at opposite two sides of the flat display region  100 . The curved display region  200  is bent away from a display direction of the display panel. 
     Please refer to  FIGS.  3 ,  4 ,  5 ,  6 , and  7   , the display panel comprises an array substrate  10 , a pixel definition layer  20 , an organic light-emitting layer  30 , a cathode layer  50 , an encapsulation layer  60 , and an absorption layer  40 . The pixel definition layer  20  is disposed on the array substrate  10 , and the pixel definition layer  20  defines a plurality of pixel definition openings  201 . The organic light-emitting layer  30  is disposed in the pixel definition openings  201 , and the organic light-emitting layer  30  is used to emit various color lights. The cathode layer  50  is disposed on the pixel definition layer  20  and the organic light-emitting layer  30 , and the encapsulation layer  60  is disposed on the cathode layer  50  to prevent water and oxygen from entering the organic light-emitting layer  30  from outside. It should be noted that an anode layer (not illustrated in the drawings) is disposed on the array substrate  10 , and the anode layer and the organic light-emitting layer  30  are arranged corresponding to each other. 
     Specifically, the various color lights emitted by the organic light-emitting layer  30  comprise at least a first color light, a second color light, and a third color light, wherein the first color light, the second color light, and the third color light are red light, green light, and blue light in any sequence, and the first color light, the second color light, and the third color light are of different colors. 
     It should be noted that when the user views a displayed image of the display panel from a vertical viewing angle, that is, at a large viewing angle, the flat display region  100  displays a white screen since the red light, the green light, and the blue light emitted by the organic light-emitting layer  30  located in the flat display region  100  have a preset brightness ratio. However, an actual outgoing light path of the light from the curved display region  200  is longer than an actual outgoing light path of the light from the flat display region  100 , and as a result, brightness ratios of the red light, the green light, and the blue light emitted by the organic light-emitting layer  30  in the curved display region  200  and the curved display region  200  are different. Therefore, a color shift problem is caused in the curved display area  200  at a large viewing angle. For example, in comparison, when the red light has a relatively high brightness, the curved display region  200  has a red color shift; when the green light has a relatively high brightness, the curved display region  200  has a green color shift; when the blue light has a relatively high brightness, the curved display region  200  has a blue color shift. It should be noted that what color shift the curved display region  200  displays depends on the brightness and chromaticity of the red light, green light, and blue light at different viewing angles. The more common one is green color shift. The reason is that brightness attenuation of the red light in relation to viewing angles is usually greater than that of the green light in relation to viewing angles. 
     In terms of working principles, in a vertical viewing angle, when a brightness ratio of the first color light in the flat display region  100  to the first color light in the curved display region  200  is greater than a brightness ratio of the second color light in the flat display region  100  to the second color light in the curved display region  200 , and the brightness ratio of the second color light in the flat display region  100  to the second color light in the curved display region  200  is equal to a brightness ratio of the third color light in the flat display region  100  to the third color light in the curved display region  200 , then the absorption layer  40  absorbs at least a portion of the first color light, so that the first color light, the second color light, and the third color light emitted by the organic light-emitting layer  30  in the curved display region  200  and the flat display region  100  have the same brightness ratio. In other words, the red light, the green light, and the blue light emitted by the organic light-emitting layer  30  in the curved display region  200  and the flat display region  100  have the same brightness ratio. This way, the brightness ratios of the various color lights emitted by the organic light-emitting layer  30  at large viewing angles can be adjusted, and the risk of color shift in a white screen at a large viewing angle can be reduced. 
     Structurally, the absorption layer  40  is disposed on one side of the pixel definition layer  20  away from the array substrate  10 . The absorption layer  40  is arranged corresponding to at least a portion of the pixel definition layer  20  in the curved display region  200 , and configured to selectively absorb at least one color light emitted by the organic light-emitting layer  30  located in the curved display region  200 . Specifically, the absorption layer  40  can be made of a red light absorber coating or a green light absorber coating, or a blue light absorber coating which has high performance on selective absorption of red light, green light and blue light respectively. For example, when the curved display region  200  has a red color shift, the absorption layer  40  adopts a red light absorber coating, and material of the absorption layer  40  can include cadmium telluride; when the curved display region  200  has a green color shift, the absorption layer  40  adopts a green light absorber coating, and material of the absorption layer  40  can include dipyrrolborane; when the curved display region  200  has a blue color shift, the absorption layer  40  adopts a blue absorber coating, and material of the absorption layer  40  can include lotsorb absorber B-800 (2 mm, PC) or other suitable absorber paint. 
     It should be noted that the absorption layer  40  can be arranged corresponding to only a portion of the pixel definition layer  20  in the curved display region  200 , or can be arranged corresponding to all of the pixel definition layer  20  in the curved display area  200 , as long as the absorption layer  40  does not overlap the organic light-emitting layer  30  in the curved display region  200  in a vertical direction. Under this condition, the absorption layer  40  has no absorption or interference effects on the outgoing light emitted in a forward direction by the organic light-emitting layer  30  at a vertical viewing angle, so the absorption layer  40  does not cause color shift of images at the vertical viewing angle. 
     Referring to  FIG.  3   , in one embodiment, the absorption layer  40  is located between the pixel definition layer  20  and the cathode layer  50 , and is arranged corresponding to at least a portion of the pixel definition layer  20  located in the curved display region  200 . The absorption layer  40  is configured to absorb some oblique light, the cathode layer  50  covers the pixel definition layer  20 , the organic light-emitting layer  30 , and the absorption layer  40 , and the encapsulation layer  60  covers the cathode layer  50 . The present embodiment does not limit a specific structure of the encapsulation layer  60 . 
     Referring to  FIG.  4   , in one embodiment,  FIG.  4    is different from  FIG.  3    in that, the absorption layer  40  is located between the cathode layer  50  and the encapsulation layer  60 , and is arranged corresponding to at least a portion of the pixel definition layer  20  in the curved display region  200 . The absorption layer  40  is arranged on the cathode layer  50 , and the encapsulation layer  60  covers the cathode layer  50  and the absorption layer  40 . Similarly, the present embodiment does not limit the specific structure of the encapsulation layer  60 . 
     Referring to  FIG.  5   , in one embodiment,  FIG.  5    is different from  FIG.  3    in that, the absorption layer  40  is located on the encapsulation layer  60  and is arranged corresponding to at least a portion of the pixel definition layer  20  in the curved display region  200 . The cathode layer  50  covers the pixel definition layer  20  and the organic light-emitting layer  30 , and the encapsulation layer  60  covers the cathode layer  50 . Similarly, the present embodiment does not limit the specific structure of the encapsulation layer  60 . 
     Since both the cathode layer  50  and the encapsulation layer  60  are transparent, the light emitted by the organic light-emitting layer  30  located in the curved display region  200  can be transmitted through the encapsulation layer  60 . 
     Further, referring to  FIGS.  6  and  7   , the encapsulation layer  60  includes a multi-layer encapsulation structure, and the encapsulation layer  60  includes a first inorganic encapsulation layer  601 , an organic encapsulation layer  602 , and a second inorganic encapsulation layer  603  that are sequentially stacked on the cathode layer  50 .  FIGS.  6  and  7    are different from  FIGS.  3 ,  4  and  5    in that, the absorption layer  40  is located inside the encapsulation layer  60 . 
     Specifically, referring to  FIG.  6   , in one embodiment, the absorption layer  40  is located between the first inorganic encapsulation layer  601  and the organic encapsulation layer  602 , and the cathode layer  50  covers the pixel definition layer.  20  and the organic light-emitting layer  30 , the first inorganic encapsulation layer  601  is disposed on the cathode layer  50 , and the absorption layer  40  is disposed on the first inorganic encapsulation layer  601  and is arranged corresponding to at least a portion of the pixel definition layer  20  in the curved display region  200 . The organic encapsulation layer  602  covers the absorption layer  40  and the first inorganic encapsulation layer  601 , and the second inorganic encapsulation layer  603  covers the organic encapsulation layer  602 . 
     Specifically, referring to  FIG.  7   , in one embodiment, the absorption layer  40  is located between the organic encapsulation layer  602  and the second inorganic encapsulation layer  603 , and the cathode layer  50  covers the pixel definition layer.  20  and the organic light emitting layer  30 , the first inorganic encapsulation layer  601  covers the cathode layer, the organic encapsulation layer  602  covers the first inorganic encapsulation layer  601 , and the absorption layer  40  is disposed on the organic encapsulation layer and is arranged corresponding to at least a portion of the pixel definition layer  20  in the curved display region  200 . The second inorganic encapsulation layer  603  covers the absorption layer  40  and the organic encapsulation layer  602 . 
     Selectively, materials of the first inorganic encapsulation layer  601  and the second inorganic encapsulation layer  603  comprise SiNx, SiONx, and AlOx, and materials of the organic encapsulation layer  602  comprise acrylic organic polymers. 
     Specifically, thicknesses of the first inorganic encapsulation layer  601  and the second inorganic encapsulation layer  603  range from 1 nm to 10 μm, and a thickness of the organic encapsulation layer  602  ranges from 10 nm to 20 μm. 
     It should be noted that, in the embodiments shown in  FIG.  6    and  FIG.  7   , the encapsulation layer  60  is a three-layer encapsulation structure, but the present invention is not limited in this regard. The encapsulation layer  60  can also be an encapsulation structure having five, seven, or more layers. There are more possibilities for the specific position of the absorption layer  40  as the structure of the encapsulation layer  60  may change. Such changes are within the protection scope of the present application, and a detailed description thereof is omitted herein. 
     Specifically, a thickness of the absorption layer  40  ranges from 0.01 μm to 10 μm. 
     The present invention also provides a display device. The display device comprises the above-mentioned display panel. The display device can be a mobile terminal, a tablet computer, a sports bracelet, a remote control, or an all-in-one computer. The display device has advantages of having small color shift at a large viewing angle, and a detailed description thereof is not repeated herein for brevity. 
     In the display panel and the display device of the present invention, by providing the absorption layer corresponding to at least a portion of the pixel definition layer located in the curved display region, at least one color light emitted by the organic light-emitting layer located in the curved display region is selectively absorbed, so as to adjust the brightness ratios of the various color lights emitted by the organic light-emitting layer at large viewing angles, and reduce the risk of color shift in the white screen at large viewing angles. At the same time, the absorption layer has no absorption and interference effects on the light emitted in a forward (vertical) direction by the organic light-emitting layer at the vertical viewing angle, so that this configuration does not cause color shift of the image at the vertical viewing angle, and the display performance of the display panel is improved. 
     In summary, although the present invention has been disclosed in preferable embodiments as above, the above-mentioned embodiments are not intended to limit the present invention. Persons of ordinary skill in the art can make various modifications and changes. Such changes and modifications are deemed to be within the protection scope of the present invention defined by the appended claims.