Patent Publication Number: US-2023157047-A1

Title: Organic light emitting diode display

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a Continuation of U.S. patent application Ser. No. 17/373,256, filed Jul. 12, 2021, which is a Continuation of U.S. patent application Ser. No. 16/577,475, filed Sep. 20, 2019, which issued as U.S. Pat. No. 11,063,233, which is a Continuation of U.S. patent application Ser. 15/669,653, filed Aug. 4, 2017, which issued as U.S. Pat. No. 10,431,764, which is a Continuation of U.S. patent application Ser. No. 14/476,809, filed Sep. 4, 2014, which issued as U.S. Pat. No. 9,728,744, which claims priority from Korean Patent Application No. 10-2013-0123512, filed on Oct. 16, 2013, each of which is hereby incorporated by reference for all purposes as if fully set for the herein. 
    
    
     BACKGROUND 
     1. Field 
     Embodiments relate to an organic light emitting diode (OLED) display and to an OLED display including a pixel defining layer. 
     2. Description of the Related Art 
     A display device is a device displaying an image. An OLED display has recently received attention. The OLED display may have self-luminous characteristics and does not generally require a separate light source, unlike a liquid crystal display device, and thus can have reduced thickness and weight. Further, the OLED display may have high-quality characteristics, such as low power consumption, high luminance, and a high reaction speed. 
     SUMMARY 
     Embodiments are directed to an organic light emitting diode display that include a first substrate, a plurality of electrodes on the first substrate and spaced apart from each other, a pixel defining layer on the plurality of electrodes, spacers on the pixel defining layer, and a second substrate on the spacers. The pixel defining layer includes a plurality of openings spaced apart from each other and respectively open to the plurality of electrodes. The spacers on the pixel defining layer are at crossing points of a plurality of virtual lines, the spacers crossing spaces between adjacent openings of the plurality of openings. 
     Each spacer may include a main body having a center point coincident to a respective crossing point, and protrusions protruding from the main body toward the spaces between adjacent openings. Each protrusion may have an area that may be about 3% to about 6% of an entire area of any one of the adjacent openings. Each protrusion may have an area that may be about 4.5% of an entire area of any one of the adjacent openings. The main body may have a quadrangular shape, and each protrusion may have a triangular shape. The OLED display may further include a first common layer on the electrodes and the spacers, organic light emission layers on the first common layer corresponding to the plurality of openings, and a second common layer on the first common layer, and on the light emission layers and the spacers. 
     An OLED display includes a first substrate, a plurality of first electrodes on the first substrate, a plurality of second electrodes, a plurality of third electrodes, a pixel defining layer, spacers, and a second substrate on the spacers. The plurality of first electrodes is spaced apart from each other in a first direction extending along a surface of the first substrate. Each of the plurality of second electrodes is between adjacent ones of the plurality of first electrodes in the first direction. The plurality of third electrodes is spaced apart from each other in a second direction parallel to the first direction, and corresponds to the adjacent first electrodes and second electrodes, respectively. The pixel defining layer is on the first electrodes, the second electrodes, and the third electrodes. The pixel defining layer includes first openings open to a part of the first electrodes, second openings spaced apart from the first openings and open to a part of the second electrodes, and third openings spaced apart from the second openings and open to a part of the third electrodes. The spacers are on the pixel defining layer at crossing points of first virtual lines. The spacers cross first spaces between the first openings and the second openings. The second virtual lines cross second spaces between the first openings and the third openings. 
     Each spacer may include a main body at a respective crossing point, a first protrusion protruding from the main body toward a respective first space between a respective one of the first openings and a respective one of the second openings, a second protrusion protruding from the main body toward a respective second space between the respective one of the first openings and a respective one of the third openings, and a third protrusion protruding from the main body toward a third space between the the respective one of the second openings and the respective one of the third openings. Each spacer may have a quadrangular shape. Each of the respective first openings, the respective second openings, and the respective third openings may have a rectangular shape. One or more of the first protrusion, the second protrusion, and the third protrusion may have an area that may be 3% to 6% of an entire area of any one of the respective first openings and the respective second openings. One or more of the first protrusion, the second protrusion, and the third protrusion may have an area that may be about 4.5% of an entire area of any one of the respective first openings and the respective second openings. Each spacer may be spaced apart from the respective third openings by about 7 μm to about 14 μm. Each spacer may be spaced apart from the respective third openings by about 13 μm. The OLED display may have a quadrangular shape, and each of the first protrusion, the second protrusion, and the third protrusion may have a triangular shape. A first corner of the main body may be adjacent to a first corner of the respective one of the first openings, and a second corner of the main body may be adjacent to a first corner of the respective one of the second openings. 
     The OLED display may further include: a first common layer on the first electrodes, the second electrodes, the third electrodes, and the spacers; a first organic light emission layer on the first common layer corresponding to the first openings; a second organic light emission layer on the first common layer corresponding to the second openings; a third organic light emission layer on the first common layer corresponding to the third openings; and a second common layer on the first common layer, and on the first organic light emission layer, the second organic light emission layer, the third organic light emission layer, and the spacer. Each of the first organic light emission layer, the second organic light emission layer, and the third organic light emission layer may emit light of a different color. The third organic light emission layer may emit blue light, and any one of the first organic light emission layer and the second organic light emission layer may emit red light, and the other one may emit green light. The pixel defining layer and the spacer may be integral. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features will become apparent to those of skill in the art by describing in detail embodiments with reference to the attached drawings in which: 
         FIG.  1    illustrates a top plan view of a part of an OLED display according to a first embodiment. 
         FIG.  2    illustrates a cross-sectional view taken along line II-II of  FIG.  1   . 
         FIG.  3    illustrates a top plan view of a part of an OLED display according to another embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey exemplary implementations to those skilled in the art. In the drawing figures, the dimensions of layers and regions may be exaggerated for clarity of illustration. In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for understanding and ease of description, in a non-limiting manner. Like reference numerals refer to like elements throughout. In addition, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” or “comprising,” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. 
     An OLED display is described with reference to  FIGS.  1  and  2   .  FIG.  1    illustrates a top plan view of a part of an OLED display.  FIG.  1    mainly illustrates a first electrode, a pixel defining layer, an organic light emission layer, and a spacer.  FIG.  2    illustrates a cross-sectional view taken along line II-II of  FIG.  1   . As illustrated in  FIGS.  1  and  2   , an OLED display  1000  may include a first substrate SU 1 , a circuit unit PC, first electrodes E 1 , second electrodes E 2 , third electrodes E 3 , a pixel defining layer PDL, spacers SPC, a first common layer CL 1 , a first organic light emission layer OL 1 , a second organic light emission layer OL 2 , a third organic light emission layer OL 3 , a second common layer CL 2 , a common electrode CE, and a second substrate SU 2 . 
     The first substrate SU 1  may include an insulating substrate made of glass, quartz, ceramic, metal, plastics, and the like. Further, for example, where the first substrate SU 1  is made of plastics and the like, the OLED display may have a flexible characteristic, and a stretchable or rollable characteristic. 
     The circuit unit PC may be on the first substrate SU 1 , and may include wires including one or more scan lines, data lines, driving power lines, common power lines and the like, pixel circuits, such as two or more thin film transistors (TFT) and one or more capacitors, and the like connected to the wires to correspond to one pixel. The circuit unit PC may include various suitable structures. The term “pixel” refers to a minimum unit of displaying an image. 
     The first electrodes E 1  may be on the first substrate SU 1 . The number of first electrodes E 1  may be plural. The respective first electrodes E 1  may be spaced apart from each other in a first direction L 1  extended along a surface of the first substrate SU 1 . The second electrodes E 2  may be on the first substrate SU 1 , and the number of second electrodes E 2  may be plural. Each of the plurality of second electrodes E 2  may be between adjacent first electrodes E 1  in the first direction L 1 . The third electrodes E 3  may be on the first substrate SU 1 , and the number of third electrodes E 3  may be plural. The respective third electrodes E 3  may be to be spaced apart from each other in a second direction L 2  parallel to the first direction L 1 . First and second directions L 1 , L 2 , may each be considered as an array extending in two directions, for example, forwards and backwards along a common axis. The third electrodes E 3  may correspond to the first electrodes E 1  and the second electrodes E 2 . The third electrode E 3  may have a larger area than the first electrode E 1  and the second electrode E 2 . Each of the first electrode E 1 , the second electrode E 2 , and the third electrode E 3  may be an anode electrode serving as a hole injection electrode or may be a cathode electrode. The first electrode E 1 , the second electrode E 2 , and the third electrode E 3  may each independently be a light transmissive electrode, a light transflective electrode, or a light reflective electrode. One or more types of electrode may overlap, in part, with one or more other types of electrode. Any electrode may partially overlap with one or more other electrodes. For example, two or more of the first electrode E 1 , the second electrode E 2 , and the third electrode E 3  may overlap partially with one another. 
     The pixel defining layer PDL may be on the first electrode E 1 , the second electrode E 2 , and the third electrode E 3 , and may cover a border of each of the first electrode E 1 , the second electrode E 2 , and the third electrode E 3 . The pixel defining layer PDL may include first openings OM 1 , second openings OM 2 , and third openings OM 3  through which a part of each of the first electrodes E 1 , the second electrodes E 2 , and the third electrodes E 3  are opened. The first opening OM 1  may be open to a part of the first electrode E 1 , and may have a substantially rectangular shape. The first opening OM 1  may be spaced apart from the third opening OM 3  and the second opening OM 2 , and may have a smaller area than the third opening OM 3 . The first opening OM 1  may have a polygonal shape, for example, such as a triangle, quadrangular shape, a rectangle, a pentagon, a hexagon, a heptagon, and an octagon. The number of first openings OM 1  may be plural, and each of the plurality of first openings OM 1  may open to a part of one of the plurality of first electrodes E 1 . The first organic light emission layer OL 1  emitting red light may be on the first electrode E 1  open to the first opening OM 1 . 
     Organic light emission layers emitting light of various colors, such as blue, green, and white, may be on the first electrode E 1  open to the first opening OM 1 . 
     The second opening OM 2  may open to a part of the second electrode E 2 , and may have a substantially rectangular shape. The second opening OM 2  may be spaced apart from the third opening OM 3  and the first opening OM 1 , and may have a smaller area than the third opening OM 3 . The second opening OM 2  may have a polygonal shape, for example, such as a triangle, quadrangular shape, a rectangle, a pentagon, a hexagon, a heptagon, and an octagon. The number of second openings OM 2  may be plural, and each of the plurality of second openings OM 2  may be open to a part of one of the plurality of second electrodes E 2 . The second organic light emission layer OL 2  emitting green light may be on the second electrode E 2  open to the second opening OM 2 . Organic light emission layers emitting light of various colors, such as blue, red, and white, may be on the second electrode E 2  open to the second opening OM 2 . 
     The third opening OM 3  may be open to a part of the third electrode E 3 , and may have a substantially rectangular shape. The third opening OM 3  may be spaced apart from the first opening OM 1  and the second opening OM 2 , and may have a larger area than the first opening OM 1  and the second opening OM 2 . The third opening OM 3  may have a polygonal shape, for example, such as a triangle, quadrangular shape, a rectangle, a pentagon, a hexagon, a heptagon, and an octagon. The number of third openings OM 3  may be plural, and each of the plurality of third openings OM 3  may be open a part of one of the plurality of third electrodes E 3 . The third organic light emission layer OL 3  emitting blue light may be on the third electrode E 3  opened to the third opening OM 3 . Organic light emission layers emitting various colors, such as green, red, and white, and may be on the third electrode E 3  open to the third opening OM 3 . The aforementioned first opening OM 1 , second opening OM 2 , and third opening OM 3  may be spaced apart from each other, and a short side of each of the first opening OM 1  and the second opening OM 2  may face a long side of the third opening OM 3 . 
     The spacer SPC may be on a topmost portion of the pixel defining layer PDL. 
     The spacer SPC may be at a crossing point of a first virtual line VL 1  crossing a space between the first opening OM 1  and the second opening OM 2 , and a second virtual line VL 2  crossing a space between the first opening OM 1  and the third opening OM 3 . The spacer SPC may be at a point at which the first opening OM 1 , the second opening OM 2 , and the third opening OM 3  are adjacent to each other, not between the first opening OM 1  and the second opening OM 2 . The number of spacers SPC may be plural, and each of the plurality of spacers SPC may be at a crossing point of one of the plurality of first virtual lines VL 1  and one of the plurality of second virtual lines VL 2 . The spacer SPC may include a main body MB, a first protrusion PR 1 , a second protrusion PR 2 , and a third protrusion PR 3 . 
     The main body MB may be at a crossing point of the first virtual line VL 1  and the second virtual line VL 2 . The main body MB may have a quadrangular shape. The main body MB may have a polygonal shape, for example, such as a triangle, quadrangular shape, a rectangle, a pentagon, a hexagon, a heptagon, and an octagon. One corner of the main body MB spaced apart from the third opening OM 3  may be adjacent to a corner of the first opening OM 1 , and the other corner of the main body MB spaced apart from the third opening OM 3  may be adjacent to a corner of the second opening OM 2 . The main body MB may be spaced apart from the first opening OM 1 , the second opening OM 2 , and the third opening OM 3 . For example, the main body MB may be spaced apart from the third opening OM 3  by a spaced distance LE of about 7 μm to about 14 μm. For example, the main body MB may be spaced apart from the third opening OM 3  by a spaced distance LE of about 13 μm from the third opening OM 3 . 
     The first protrusion PR 1  may protrude from the main body MB toward a space between the first opening OM 1  and the second opening OM 2  along the first virtual line VL 1 , and may have a triangular shape. The second protrusion PR 2  may protrude from the main body MB toward a space between the first opening OM 1  and the third opening OM 3  along the second virtual line VL 2 , and may have a triangular shape. The third protrusion PR 3  may protrude from the main body MB toward a space between the second opening OM 2  and the third opening OM 3  along the second virtual line VL 2 , and may have a triangular shape. 
     One or more of the first protrusion PR 1 , the second protrusion PR 2 , and the third protrusion PR 3  may have an area that is, for example, about 3% to about 6% of the entire area of any one of the first opening OM 1  and the second opening OM 2 , or, for example, may have an area substantially that is about 4.5% of the entire area of any one of the first opening OM 1  and the second opening OM 2 . A combined area of the two first protrusions PR 1  facing along the first virtual line VL 1  may have an area of, for example, about 6% to about 12% of the entire area of any one of the first opening OM 1  and the second opening OM 2 , or, for example, may substantially have an area of about 9% of the entire area of any one of the first opening OM 1  and the second opening OM 2 . Further, a combined area of the second protrusion PR 2  and the third protrusion PR 3  facing along the second virtual line VL 2  may have an area, for example, of about 6% to about 12% of the entire area of any one of the first opening OM 1  and the second opening OM 2 , or, for example, may substantially have an area of about 9% of the entire area of any one of the first opening OM 1  and the second opening OM 2 . The spacer SPC may be integral with the pixel defining layer PDS, or may include a different material from that of the pixel defining layer PDL. 
     The first common layer CL 1  may be on the first electrode E 1 , the second electrode E 2 , the third electrode E 3 , the pixel defining layer PDL, and the spacer SPC, and may include one or more layers selected from a hole injection layer, a hole transporting layer, an electron injection layer, and an electron transporting layer. The first organic light emission layer OL 1  may be on the first common layer CL 1  on the first electrode E 1  to correspond to the first opening OM 1 . The first organic light emission layer OL 1  may include an organic material emitting red light, and may emit red light. 
     The first organic light emission layer OL 1  may include an organic material emitting light of green, blue, or white, and, for example, the first organic light emission layer OL 1  may emit green, blue, or white light. 
     The second organic light emission layer OL 2  may be on the first common layer CL 1  on the second electrode E 2  to correspond to the second opening OM 2 . The second organic light emission layer OL 2  may include an organic material emitting green light, and may emit green light. The second organic light emission layer OL 2  may include an organic material emitting red, blue, or white light, and, for example, the second organic light emission layer OL 2  may emit red, blue, or white light. 
     The third organic light emission layer OL 3  may be on the first common layer CL 1  on the third electrode E 3  to correspond to the third opening OM 3 . The third organic light emission layer OL 3  may include an organic material emitting blue light, and may emit blue light. 
     The third organic light emission layer OL 3  may include an organic material emitting red, green, or white light, and, for example, the third organic light emission layer OL 3  may emit red, green, or white light. The aforementioned first organic light emission layer OL 1 , second organic light emission layer OL 2 , and third organic light emission layer OL 3  may emit light of different colors, respectively. Further, the third organic light emission layer OL 3  may emit blue light, and any one of the first organic light emission layer OL 1  and the second organic light emission layer OL 2  emits red light, and the other one may emit green light. 
     The second common layer LC 2  may be on the first common layer CL 1  on the first organic light emission layer OL 1 , the second organic light emission layer OL 2 , the third organic light emission layer OL 3 , the pixel defining layer PDL, and the spacer SPC, and may include one or more layers selected from a hole injection layer, a hole transporting layer, an electron injection layer, and an electron transporting layer. The common electrode CE may be on the second common layer CL 2  over an entire surface or partial surface of the first substrate 
     SU 1 , and may be a cathode serving as an electron injection electrode, or an anode serving as a hole injection electrode. The common electrode CE may include a light transmissive electrode or a light reflective electrode. The second substrate SU 2  may include an insulating substrate including glass, quartz, ceramic, metal, plastics, or the like. Further, for example, when the second substrate SU 2  is made of plastics or the like similar to the first substrate SU 1 , the OLED display may have a flexible characteristic, a stretchable characteristic, and/or rollable characteristic. 
     In the OLED display  1000 , the spacer SPC may be at the crossing point of the first virtual line VL 1  crossing the space between the first opening OM 1  and the second opening OM 2  and the second virtual line VL 2  crossing the space between the first opening OM 1  and the third opening OM 3 . If the second substrate SU 2  is bent due to external force, the second substrate SH 2  may come into contact with the spacer SPC, and the material of the second common layer CL 2  on the spacer SPC may be unintentionally transferred to the second substrate SU 2 . The material transferred to the second substrate SU 2  is not on the first opening OM 1 , the second opening OM 2 , and the third opening OM 3  even when the external force is removed and the second substrate SU 2  returns to a flat form. A spot may be suppressed from being generated in light emitted through the first opening OM 1 , the second opening OM 2 , and the third opening OM 3  from the first organic light emission layer OL 1 , the second organic light emission layer OL 2 , and the third organic light emission layer OL 3 . 
     In the OLED display  1000 , the spacer SPC may include the first protrusion PR 1  extended from the main body MB along the first virtual line VL 1 , and the second protrusion PR 2  and the third protrusion PR 3  may extend from the main body MB along the second virtual line VL 2 . Therefore, even though the second substrate SU 2  may be bent due to external force, the second substrate SU 2  may be suppressed from being in contact with the first organic light emission layer OL 1 , the second organic light emission layer OL 2 , and the third organic light emission layer OL 3  exposed by the first opening OM 1 , the second opening OM 2 , and the third opening OM 3 , respectively. 
     In the OLED display  1000 , even though the spacer SPC may include the first protrusion PR 1  and extending from the main body MB along the first virtual line VL 1 , and the second protrusion PR 2  and the third protrusion PR 3  extending from the main body MB along the second virtual line VL 2 , each of the first protrusion PR 1 , the second protrusion PR 2 , and the third protrusion PR 3  may have a triangular shape, and the combined area of the two first protrusions PR 1  facing each other along the first virtual line VL 1  may have the area that may be, for example, about 6% to about 12% of the entire area of any one of the first opening OM 1  and the second opening OM 2 . The combined area of the second protrusion PR 2  and the third protrusion PR 3  facing each other along the second virtual line VL 2  may have an area, for example, of about 6% to about 12% of the entire area of any one of the first opening OM 1  and the second opening OM 2 . For example, when the second substrate SU 2  is bent due to external force and comes into contact with the first protrusion PR 1 , the second protrusion PR 2 , and the third protrusion PR 3  such that the material of the second common layer CL 2  on the spacer SPC is unintentionally transferred to the second substrate SU 2 , the material transferred to the second substrate SU 2  may not be positioned on the first opening OM 1 , the second opening OM 2 , or the third opening OM 3  even after the external force is removed and the second substrate returns to a flat form. A spot may be suppressed from being generated in light emitted through the first opening OM 1 , the second opening OM 2 , and the third opening OM 3  from the first organic light emission layer OL 1 , the second organic light emission layer OL 2 , and the third organic light emission layer OL 3 . The OLED display  1000  may be provided in which a spot is suppressed from being generated in an image displayed by light emitted from each of the first organic light emission layer OL 1 , the second organic light emission layer OL 2 , and the third organic light emission layer OL 3 . 
     An OLED display according to another embodiment is described with reference to  FIG.  3   .  FIG.  3    illustrates a top plan view of a part of the OLED display according to the embodiment. As illustrated in  FIG.  3   , a spacer SPC of an OLED display  1002  according to the second embodiment at a crossing point of a first virtual line VL 1  and a second virtual line VL 2 , and may have a quadrangular shape. In the OLED display  1002  according to the second embodiment, the spacer SPC may be at a crossing point of the first virtual line VL 1  crossing a space between a first opening OM 1  and a second opening OM 2  and the second virtual line VL 2  crossing a space between the first opening OM 1  and a third opening OM 3 , and may have a quadrangular shape. For example, when a second substrate SU 2  is bent due to external force and comes into contact with the spacer SPC such that a material of a second common layer CL 2  on the spacer SPC is unintentionally transferred to the second substrate SU 2 , the material transferred to the second substrate SU 2  need not be positioned on the first opening OM 1 , the second opening OM 2 , or the third opening OM 3  even when the external force is removed and the second substrate SU 2  returns to a flat form. A spot may be suppressed from being generated in light emitted through the first opening OM 1 , the second opening OM 2 , and the third opening OM 3  from a first organic light emission layer OL 1 , a second organic light emission layer OL 2 , and a third organic light emission layer OL 3 . The OLED display  1002  may be provided in which a spot may be suppressed from being generated in an image displayed by light emitted from the first organic light emission layer OL 1 , the second organic light emission layer OL 2 , and the third organic light emission layer OL 3 . 
     By way of summation and review, an OLED display may include a first substrate, a pixel circuit including a thin film transistor, a first electrode connected with the pixel circuit, a pixel defining layer including a plurality of openings through which the first electrode may be exposed, a spacer on the pixel defining layer, an organic light emission layer on the first electrode to correspond to the opening, a second electrode on the organic light emission layer, and a second substrate on the second electrode. The spacer may be between the adjacent openings, and when, for example, the second substrate may be bent due to external force, the second substrate may be in contact with the spacer, so that a material on the spacer may be unintentionally transferred to the second substrate. For example, when the second substrate returns to a flat form after removing the external force, the material transferred to the second substrate may be on the opening such that a spot may be generated in light emitted through the opening from the organic light emission layer. 
     As described herein, an OLED display is provided in which even though the second substrate may be bent due to external force so that a material on the spacer may is transferred to the second substrate, the material transferred to the second substrate may be suppressed from being on the opening. 
     Example embodiments have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. In some instances, as would be apparent to one of ordinary skill in the art as of the filing of the present application, features, characteristics, and/or elements described in connection with a particular embodiment may be used singly or in combination with features, characteristics, and/or elements described in connection with other embodiments unless otherwise specifically indicated. Accordingly, it will be understood by those of skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present disclosure as set forth in the following claims.