Patent Description:
A display device is a device that displays an image. Recently, an OLED display has been drawing attention.

The OLED display has a self-luminous characteristic. Because the OLED display does not need a separate light source, unlike a liquid crystal display, it can have a relatively smaller thickness and weight than liquid crystal displays. In addition, the OLED display exhibits high-quality characteristics such as low power consumption, high luminance, high response speed, etc..

In general, the OLED display includes a plurality of pixels for emitting light of different colors. The plurality of pixels emit light to display an image.

Here, the pixel refers to a minimum unit for displaying the images. For instance, there may be a gate line, a data line, and a power line such as a driving power line to drive each pixel. In addition, there may be an insulation layer such as a pixel definition layer to define an area and a shape of each pixel. Further, each pixel may be positioned between its neighboring pixels.

An organic emission layer included in the pixel of an OLED display may be deposited and formed by using a mask such as a fine metal mask (FMM). When reducing a gap between the neighboring pixels to obtain a high aperture ratio of the pixels, deposition reliability may be deteriorated. On the other hand, when increasing the gap between the pixels to improve the deposition reliability, the aperture ratio of the pixels may be deteriorated.

For instance, <CIT> - which constitutes prior art under Art. <NUM>(<NUM>) EPC - is directed to a pixel arrangement for an OLED display, wherein the pixels may have different polygonal shapes. Furthermore, <CIT> and <CIT> both disclose a pixel arrangement for display panels wherein pixels of a first color are surrounded by four pixels of different colors.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

Aspects of embodiments of the present invention relate generally to a pixel arrangement structure for an OLED display. More particularly, aspects of embodiments of the present invention relate to a pixel arrangement structure of an OLED display that displays an image by emitting light through a plurality of pixels.

An exemplary embodiment of the present invention provides a pixel arrangement structure for an OLED display having an improved aperture ratio of each of the pixels while efficiently setting up gaps between the pixels.

According to an exemplary embodiment of the present invention, a pixel arrangement structure of an organic light emitting diode (OLED) display is provided according to claim <NUM>.

The further embodiments are defined in dependent claims.

According to an exemplary embodiment of the present invention, the pixel arrangement structure of the OLED display improves the aperture ratio of the pixels while efficiently setting up the gaps between the pixels.

<FIG> is a view of a pixel arrangement structure of an OLED display according to an exemplary embodiment of the present invention.

Several exemplary embodiments according to the present invention are described hereinafter in detail with reference to the accompanying drawing to allow one of ordinary skill in the art to practice the invention without undue experimentation. The present invention can be embodied in several different forms, and is not limited to the exemplary embodiments that are described herein.

In order to clarify the description of embodiments of the present invention, parts that are not related to the invention may be omitted. In addition, the same elements or equivalents are referred to with the same reference numerals throughout the specification.

Further, since sizes and thicknesses of constituent members shown in the accompanying drawing may be arbitrarily given for better understanding and ease of description, the present invention is not limited to the illustrated sizes and thicknesses.

Hereinafter, a pixel arrangement structure (or pixel arrangement) of an OLED display according to an exemplary embodiment will be described with reference to <FIG>. The drawing is a view schematically showing a portion of pixels forming an OLED display.

<FIG> shows a pixel arrangement structure of an OLED display according to an exemplary embodiment of the present invention.

As shown in <FIG>, the pixel arrangement structure of the OLED display includes a plurality of first pixels <NUM>, a plurality of second pixels <NUM>, and a plurality of third pixels <NUM>.

According to one embodiment, the pixel refers to a minimum unit for displaying an image (for example, the minimum addressable unit of the display).

In one embodiment, power lines such as a gate line, a data line, a driving power line, and the like, are located among the first pixels <NUM>, the second pixels <NUM>, and the third pixels <NUM>, for driving each of the pixels. In addition, in one embodiment, an insulation layer, such as a pixel defining layer, is provided for defining each of the pixels. Further, in one embodiment, each of the first pixels <NUM>, the second pixels <NUM>, and the third pixels <NUM> comprises an OLED including an anode, an organic emission layer, and a cathode. These configurations are technologies known in the art and further description thereof is omitted for ease of description. In one embodiment, the shape of each of the pixels is defined by the power lines, the pixel defining layer, the anode, or the like.

In the pixel arrangement of <FIG>, each of the first pixels <NUM> has a smaller area (e.g., is smaller in area) than neighboring second pixels <NUM> and third pixels <NUM>, and has a polygon shape. The first pixels <NUM> have an octagonal shape among the polygon shapes. In other embodiments, which are not part of the present invention, the first pixels <NUM> have one or more of various polygon shapes such as a triangle, a rectangle, a pentagon, a hexagon, a heptagon, and the like. For example, the first pixels <NUM> that neighbor each other among the plurality of first pixels <NUM> may have hexagon shapes that are symmetrical to each other. In one embodiment, each of the plurality of first pixels <NUM> has the same hexagonal shape.

In one embodiment, the first pixels <NUM> are spaced apart from each other and arranged in rows, such as along a first virtual straight line VL1. In one embodiment, the first pixels <NUM> emit green light, and include an organic emission layer for emitting green light. In other embodiments, the first pixels <NUM> include an organic emission layer that emits light of one or more of various colors such as blue, red, or white color for emitting blue light, red light, or white light.

In the drawing, the second pixels <NUM> are arranged diagonally with respect to the first pixels <NUM>, namely at first vertices P1 along one diagonal of a virtual square VS having one of the first pixels <NUM> as a center point (or center) of the virtual square VS. In a similar fashion, in the drawing, the third pixels <NUM> are arranged diagonally with respect to the first pixels <NUM>, namely at second vertices P2 along the other diagonal of the virtual square VS.

In the virtual square VS of the drawing, each of the second pixels <NUM> is separated from the first pixel <NUM>, and is centered at one of the first vertices P1 of the virtual square VS. Each of the second pixels <NUM> has a larger area than the neighboring first pixel <NUM> and the neighboring third pixels <NUM>, and has a hexagonal shape. In other embodiments, the second pixels <NUM> have one or more of various polygonal shapes such as a triangle, a rectangle, a pentagon, a hexagon, a heptagon, and the like.

In the drawing, the second pixels <NUM> each have the same hexagonal shape. In addition, the second pixels <NUM> are arranged diagonally and separated from each other by the first pixels <NUM>. In one embodiment, the second pixels <NUM> emit blue light, and include an organic emission layer for emitting blue light. In other embodiments, the second pixels <NUM> include an organic emission layer that emits light of one or more of various colors such as red, green, or white for emitting red light, green light, or white light.

In a similar fashion, in the virtual square VS of the drawing, each of the third pixels <NUM> is separated from the first pixel <NUM> and the second pixels <NUM>, and is centered at one of the second vertices P2 neighboring the first vertices P1 of the virtual square VS. Each of the third pixels <NUM> has a larger area than the neighboring first pixel <NUM> and a smaller area than the neighboring second pixels <NUM>. The third pixels <NUM> preferably have a quadrilateral shape among polygon shapes. In other embodiments, the third pixels <NUM> may have one or more of various polygonal shapes such as a triangle, a rectangle, a pentagon, a hexagon, a heptagon, and the like.

In <FIG>, the third pixels <NUM> each have the same quadrilateral shape. In addition, the third pixels <NUM> are arranged diagonally and separated from each other by the first pixels <NUM>. In one embodiment, the third pixels <NUM> emit red light, and include an organic emission layer for emitting red light. In other embodiments, the third pixels <NUM> include an organic emission layer that emits light of one or more of various colors such as blue, green, or white for emitting emit blue light, green light, or white light.

In <FIG>, each of the second pixels <NUM> and the third pixels <NUM> has a hexagonal shape and a quadrilateral shape, respectively. In another embodiment, each of the second pixels <NUM> and the third pixels <NUM> respectively has a quadrilateral shape and a hexagonal shape. That is, in this other embodiment, one of the second pixels <NUM> or the third pixels <NUM> has a hexagonal shape and the other has a quadrilateral shape.

In one embodiment, the first pixels <NUM>, the second pixels <NUM>, and the third pixels <NUM> respectively emit green light, blue light, and red light. In other embodiments, the first pixels <NUM>, the second pixels <NUM>, and the third pixels <NUM> emit light of the same color. In still other embodiments, the first pixels <NUM>, the second pixels <NUM>, and the third pixels <NUM> emit light of different colors. In some embodiments, the first pixels <NUM> emit green light, and one of the second pixels <NUM> or the third pixels <NUM> emit blue light while the other emit red light.

In <FIG>, the third pixels <NUM> and the second pixels <NUM> are spaced apart from each other and alternately arranged in rows, such as along a second virtual straight line VL2. In a similar fashion, in the drawing, the third pixels <NUM> and the second pixels <NUM> are spaced apart from each other and alternately arranged in columns. Accordingly, in the virtual square VS, two of the second pixels <NUM> have their corresponding centers positioned at the first vertices P1 and two of the third pixels <NUM> have their corresponding centers positioned at the second vertices P2 to enclose a corresponding one of the first pixels <NUM> in the virtual square VS.

As described and illustrated in <FIG>, the center of each of the second pixels <NUM> is positioned at one of the first vertices P1 of the virtual square VS. In addition, the center of the corresponding first pixel <NUM> is the center of the virtual square VS. Further, the center of each of the third pixels <NUM> is positioned at one of the second vertices P2. Therefore, the plurality of second pixels <NUM> of which the centers are positioned at the first vertices P1 and the plurality of third pixels <NUM> of which the centers are positioned at the second vertices P2 respectively enclose one of the first pixels <NUM> in the virtual square VS.

Further, the first pixels <NUM>, the second pixels <NUM>, and the third pixels <NUM> have polygon shapes. In <FIG>, the distance between one of the first pixels <NUM> and an adjacent one of the second pixels <NUM> as well as a distance between one of the first pixels <NUM> and an adjacent one of the third pixels <NUM> is the same first length L1. In addition, a distance between one of the second pixels <NUM> and an adjacent one of the third pixels <NUM> is a second length L2 that is different from the first length L1. Further, in the drawing, a distance between neighboring first pixels <NUM> is a third length L3 that is longer than the first length L1 and the second length L2.

For example, in some embodiments, the first length L1 is between <NUM> (micrometers) and <NUM>, the second length L2 is between <NUM> and <NUM>, and the third length L3 is between <NUM> and <NUM>.

Therefore, gaps of the first length L1 are formed between adjacent pairs of the first pixels <NUM> and the second pixels <NUM>, and between adjacent pairs of the first pixels <NUM> and the third pixels <NUM>. In addition, the gaps of the third length L3 that is longer than the first length L1 are formed between the neighboring ones of the first pixels <NUM>. In one embodiment, this results in improved deposition reliability in the deposition process using the fine metal mask to form the green, blue, and red organic emission layers respectively included in the first pixels <NUM>, the second pixels <NUM>, and the third pixels <NUM>.

In addition, in one embodiment, the plurality of second pixels <NUM> and the plurality of third pixels <NUM> are arranged to enclose the first pixels <NUM> in the virtual squares VS so that an aperture ratio of each of the first pixels <NUM>, the second pixels <NUM>, and the third pixels <NUM> can be improved. Accordingly, in one embodiment, the manufacturing time and the manufacturing cost of the OLED display is reduced and the display quality of the image of the OLED display is improved.

Further, in the pixel arrangement structure of the OLED display of the drawing according to an exemplary embodiment of the present invention, the second pixels <NUM> that emit blue light have the shortest life span among the first pixels <NUM>, the second pixels <NUM>, and the third pixels <NUM>. Accordingly, the second pixels <NUM> have a larger area than the first pixels <NUM> and the third pixels <NUM>, thereby suppressing the deterioration of the life span of the OLED display. That is, in one embodiment, the pixel arrangement structure of the OLED display of the drawing provides improved life span.

As described above, in the pixel arrangement structure of the OLED display of <FIG> according to an exemplary embodiment of the present invention, the first pixels <NUM>, the second pixels <NUM>, and the third pixels <NUM> have simple polygonal shapes such as an octagon, a hexagon, and a quadrangle. In consideration of the deposition process of the organic emission layer, which in one embodiment is a unique manufacturing feature of the OLED display, a center of one of the first pixels <NUM> is positioned at the center of the virtual square VS, a center of one of the second pixels <NUM> is positioned at the first vertex P1, and a center of one of the third pixels <NUM> is positioned at the second vertex P2 to both improve deposition reliability of the organic emission layer in the deposition process using the fine metal mask and improve an aperture of each of the first, second, and third pixels <NUM>, <NUM>, and <NUM>.

That is, according to an exemplary embodiment of the present invention as illustrated in the drawing, the pixel arrangement structure of the OLED display includes a plurality of first pixels <NUM> having an octagonal shape, a plurality of second pixels <NUM> having a hexagonal shape, and a plurality of third pixels <NUM> having a quadrilateral shape. In one or more embodiments, the shapes and arrangement of the first pixels <NUM>, the second pixels <NUM>, and the third pixels <NUM> improve the deposition reliability of the organic emission layer while also improving the aperture ratio of each of the first pixels <NUM>, the second pixels, <NUM>, and the third pixels <NUM>.

While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications included within the scope of the appendec claims.

Claim 1:
A pixel arrangement structure of an organic light emitting diode display, comprising:
first pixels (<NUM>) each having a center coinciding with a center of a virtual square (VS);
second pixels (<NUM>) separated from the first pixels (<NUM>) and each having a center at a first vertex (P1) of the virtual square (VS), wherein each of the second pixels (<NUM>) located at a first vertex (P1) of a diagonal line of the virtual square (VS) is spaced apart from a second pixel (<NUM>) located at the other vertex (P1) of the diagonal line with a first pixel (<NUM>) interposed therebetween; and
third pixels (<NUM>) separated from the first pixels (<NUM>) and the second pixels (<NUM>), and each having a center at a second vertex (P2) neighboring the first vertex (P1) of the virtual square (VS),
wherein a distance between each of the first pixels (<NUM>) and an adjacent second pixel (<NUM>) as well as a distance between each of the first pixels (<NUM>) and an adjacent third pixel (<NUM>) is a same first length (L1),
wherein a distance between each of the second pixels (<NUM>) and an adjacent third pixel (<NUM>) is a same second length (L2) different from the first length (L1), and a distance between the two adjacent first pixels (<NUM>) is a third length (L3) that is longer than the first length (L1) and the second length (L2),
wherein the first pixels (<NUM>), the second pixels (<NUM>), and the third pixels (<NUM>) have polygonal shapes,
characterized in that
the first pixels (<NUM>) have an octagonal shape, and the second pixels (<NUM>) have a different shape from a shape of the third pixels (<NUM>),
each of the second pixels (<NUM>) and the third pixels (<NUM>) is larger in area than the first pixel (<NUM>),
the first length (L1) is between <NUM> and <NUM>, the second length (L2) is between <NUM> and <NUM>, and the third length (L3) is between <NUM> and <NUM>.