Patent ID: 12219817

DETAILED DESCRIPTION

Specific implementations of the present disclosure will be described further in detail below with reference to the accompanying drawings and embodiments. The following embodiments serve to illustrate the present disclosure, but are not intended to limit the scope of the present disclosure. The embodiments in the present disclosure and the features in the embodiments may be randomly combined with each other if there is no conflict.

FIG.1is a schematic diagram of a display substrate after a pixel film layer is formed through an ink jet printing process. As shown inFIG.1, the display substrate includes a base substrate10and pixel define layers20disposed on the base substrate10. Sub-pixel regions30for accommodating print ink droplets40are formed on the base substrate10between the pixel define layers20. In the process of ink jet printing, the printing ink droplets40need to accurately drop into the sub-pixel regions30and an organic functional layer50is formed after drying. Based on the current printing technology, the diameter of a printing ink droplet40formed by the printer nozzle is substantially the same as the size of a sub-pixel region30, and it is difficult to accurately control the printing ink droplet40to fall to the predetermined position of the sub-pixel region30by dropping, resulting in uneven spreading of the printing ink droplet40in the sub-pixel region30, which further causes an uneven thickness of the organic functional layer50formed by the printing ink droplets40as well as uneven light emission of the display apparatus.

An embodiment of the present disclosure provides a display substrate, which includes a base substrate and a pixel define layer disposed on the base substrate, and the pixel define layer includes first define layers and a second define layer, wherein a printing region is formed on the base substrate between the first define layers, and the second define layer is disposed on the printing region and divides the printing region into at least two sub-printing regions. A height of the first define layers is greater than that of the second define layer in a direction perpendicular to the base substrate.

The technical solutions of the embodiments of the present disclosure will be illustrated in detail below by the embodiments.

FIG.2is a schematic diagram of a structure of a display substrate according to an embodiment of the present disclosure.FIG.3is a sectional view of a display substrate according to an embodiment of the present disclosure.FIG.3illustrates a sectional view taken along an A-A direction inFIG.2as an example to explain a structure of the display substrate of the present disclosure. The type of the display substrate in the embodiments of the present disclosure is not limited, for example, it may be an OLED display substrate or quantum dot display substrate. The present description takes an OLED display substrate as an example. As shown inFIG.2andFIG.3, the display substrate of the embodiment of the present disclosure includes a base substrate10and a pixel define layer20disposed on the base substrate10, wherein the pixel define layer20includes first define layers201and a second define layer202. A printing region60is formed on the base substrate10between the first define layers201, and the second define layer202is disposed on the printing region60and divides the printing region60into at least two sub-printing regions, wherein a height of the first define layers201is greater than that of the second define layer202in a direction perpendicular to the base substrate10.

According to the embodiment of the present disclosure, the first define layers201form a printing region60on the base substrate10, so that printing ink droplets can accurately flow into the printing region60under the restriction of the first define layers201. At least two sub-printing regions are formed in the printing region60by the second define layer202, so that the printing ink droplets in the printing region60accurately flow into the sub-printing regions under the restriction of the second define layer202and are spread evenly on the sub-printing regions, thereby ensuring the thickness uniformity of the film formation of the sub-pixel regions.

In an exemplary embodiment, the material of the base substrate10is not limited, which may be a rigid material. In an exemplary embodiment, the material may include, but is not limited to, silicon wafer, glass, mica sheet or other rigid carrier materials.

In an exemplary embodiment, in the direction perpendicular to the base substrate10, the height of the second define layer202is ⅓ to ¾ of the height of the first define layers201, so that the printing droplets will not overflow the first define layers201, and the printing droplets in the printing region will be spread evenly under the restriction of the second define layer202, making the printing droplets uniformly form a film. For example, the height of the first define layers201ranges from 1 μm to 5 μm, and the height of the second define layer202ranges from 0.34 μm to 3.75 μm.

In an exemplary embodiment, the base substrate10is provided with at least two adjacent printing regions60, and sub-printing regions in at least two of the adjacent printing regions60are combined to form a pixel region70. In an exemplary embodiment, in the direction parallel to the base substrate10, the printing region60is a regular hexagon. A first define layer201is a regular hexagon and is disposed around the printing region60. The second define layer202is disposed along a diagonal direction of the printing region60, and two ends of the second define layer202are connected with the first define layers201. The second define layer202evenly divides the printing region60into two sub-printing regions, both of which are isosceles trapezoid and symmetrically disposed with the second define layer202as the center line. The adjacent printing regions60on the substrate10at least include a first sub-printing region301, a second sub-printing region302and a third sub-printing region303, wherein the first sub-printing region301, the second sub-printing region302and the third sub-printing region303are adjacent to each other. A printing region60on a side of the first sub-printing region301close to the second sub-printing region302and the third sub-printing region303is configured as a red sub-pixel region, a printing region60on a side of the second sub-printing region302close to the first sub-printing region301and the third sub-printing region303is configured as a green sub-pixel region, and a printing region60on a side of the third sub-printing region303close to the first sub-printing region301and the second sub-printing region302is configured as a blue sub-pixel region. The part of printing region60on the side of the first printing region301close to the second sub-printing region302and the third sub-printing region303, the part of printing region60on the side of the second sub-printing region302close to the first sub-printing region301and the third sub-printing region303, and the part of printing region60on the side of the third sub-printing region303close to the first sub-printing region301and the second sub-printing region302are combined and to form the triangle pixel region70. Among them, adjacent printing regions60means that one edge of the adjacent printing regions60shares the first define layer201.

In an exemplary embodiment, in the direction parallel to the base substrate10, the pixel region70may be triangular to increase an effective display area of the pixel region70.

In some embodiments, the printing region may have various shapes, such as regular or irregular shapes such as triangles, rectangles, quadrangles, pentagons, etc., which will not be repeated here in the present disclosure.

In some embodiments, the pixel region may be have various shapes, such as regular or irregular shapes such as rectangle, quadrilateral, pentagon, etc., which will not be repeated here in the present disclosure.

In an exemplary embodiment, the display substrate of the embodiment of the present disclosure further includes a drive circuit layer disposed on the base substrate10, wherein the drive circuit layer includes a plurality of drive transistors, and the drive transistors are in one-to-one correspondence with the sub-printing regions in the printing region and are configured to drive the organic functional layers on the sub-printing regions in the printing region to emit light.

In an exemplary embodiment, in the direction perpendicular to the base substrate10, a first define layer201includes a first hydrophilic material layer and a first hydrophobic material layer which are stacked, and the first hydrophobic material layer is located on a side of the first hydrophilic material layer away from the base substrate10. The second define layer202includes a second hydrophilic material layer; or, the second define layer202includes a second hydrophilic material layer and a second hydrophobic material layer located on a side of the second hydrophilic material layer away from the base substrate10. Among them, the first hydrophobic material layer and the second hydrophobic material layer are made of hydrophobic materials, which can restrict printing ink droplets to dropping into designated printing regions and sub-printing regions, effectively control the climbing of printing ink droplets on the first and second defined layers, and improve the uniformity of film formation. The hydrophobic material is a material having repellency to ink in which an organic electroluminescent material is dissolved. The hydrophobic material may be fluorinated polymethylmethacrylate or fluorinated polyimide. The first hydrophilic material layer and the second hydrophilic material layer are hydrophilic materials, and the first hydrophilic material layer and the second hydrophilic material layer better attract printing ink droplets by utilizing the characteristics of the hydrophilic materials, so as to ensure that the printing ink droplets are completely and adequately spread and form a film uniformly in the drying process. The hydrophilic material is a material attractive to a solution in which an organic electroluminescent material is dissolved. The hydrophilic material may be one of polyisoprene, polystyrene and epoxy resin.

A manufacturing process of the display substrate in the present embodiment includes:

In Step 1, an anode layer is formed on a base substrate. Forming an anode layer on the base substrate includes depositing a conductive thin film on the base substrate10, patterning the conductive thin film through a patterning process, and forming an anode layer pattern (not shown in the figures) on the base substrate10; herein, the conductive thin film may be made of a metal material, such as argentum (Ag), copper (Cu), aluminum (Al), molybdenum (Mo), or an alloy material of the above metals, such as aluminum neodymium alloy (AlNd), molybdenum niobium alloy (MoNb), or may be multi-layer metals, such as molybdenum (Mo)/copper (Cu)/molybdenum (Mo), or may be in a stacked structure formed by a metal and a translucent conductive material, such as indium tin oxide (ITO)/argentum (Ag)/indium tin oxide (ITO).

In Step 2, a pixel define layer is formed on a base substrate. Forming the pixel define layer on the base substrate includes depositing a pixel define thin film on the base substrate10on which the aforementioned patterns are formed; wherein the pixel define thin film is made of photosensitive material. Irradiating a gray mask plate with a light source, wherein light passes through a completely light transmittance region of the gray mask plate, so that the pixel define thin film in the completely light transmittance region becomes a completely exposed region, and the pixel define thin film in the completely exposed region is completely removed after development. The light cannot pass through a non-light transmittance region of the gray mask plate, so that the pixel define thin film in the non-light transmittance region becomes an unexposed region, and the pixel define thin film in the unexposed region is completely retained after development to form the first define layer201. The light passes through a partially light transmittance region of the gray mask plate, so that the pixel define thin film in the partially light transmittance region becomes a partially exposed region, and the pixel define thin film in the partially exposed region is partially removed after development to form a second define layer202. The first define layer s201and the second define layer202form a pixel define layer20, as shown inFIG.3. The base substrate10between the first define layers201forms a printing region60, and the second define layer202is disposed on the printing region60and divides the printing region60into at least two sub-printing regions. In the direction perpendicular to the base substrate10, the height of the first define layer201is greater than that of the height of the second define layer202.

In an exemplary embodiment, the base substrate may be an array substrate. Before formation of the anode layer and the pixel define layer, a drive circuit layer may be formed on the base substrate10in advance. The drive circuit layer includes a plurality of drive transistors, and the drive transistors are in one-to-one correspondence with the sub-printing regions in the printing region.

In an exemplary embodiment, the anode layer includes an anode located in each sub-pixel region, and the anode in each sub-pixel region may be connected with a drive transistor corresponding to the sub-pixel region through a via hole in the sub-pixel region.

FIG.4is a first sectional view of a display substrate after film formation according to the embodiment of the present disclosure. An embodiment of the disclosure further provides an ink jet printing method for a display substrate, which may be applied to any one of the aforementioned display substrates, and the method includes:ejecting printing ink droplets40into a printing region60of the display substrate through a nozzle, wherein the printing ink droplets40cover at least two sub-printing regions in the printing region60; andusing an evaporation process (e.g., vacuum evaporation process) to make the printing ink droplets40form an organic functional layer50, as shown inFIG.4. Among them, the organic functional layer may include one or more of the following: hole injection layer, hole transport layer, light-emitting layer, electron injection layer and electron transport layer.

In an exemplary embodiment, after the printing ink droplets40drop into the printing region60, the printing ink droplets40are separated by the second define layer202on the printing region60, so that the printing ink droplets40on adjacent sub-printing regions in the printing region60are disconnected at the second define layer202, and then the organic functional layers50formed by the printing ink droplets40are disconnected at the second define layer202, as shown inFIG.4.

FIG.5is a second sectional view of a display substrate after film formation according to the embodiment of the present disclosure. In an exemplary embodiment, as shown inFIG.5, the printing ink droplets40drop into and are spread in the printing region60, and the printing ink droplets40cover the sub-printing regions and the second define layer202in the printing region60, so that the organic functional layers50formed by the printing ink droplets40is a continuous film layer, and a vertical projection of the organic functional layer50on the base substrate10overlaps with a vertical projection of the printing region60on the base substrate10.

According to the embodiment of the present disclosure, dropping printing ink droplets40into the printing region60makes the printing ink droplets40cover at least two sub-printing regions in the printing region60, and the organic functional layers50on at least two sub-printing regions in the printing region60are manufactured by the same printing ink droplets40, which can form smaller sub-pixel units without changing the accuracy of printing equipment.

An embodiment of the present disclosure further provides a display apparatus which includes any one of the above display substrates. The display apparatus may be any product or component with a display function such as a mobile phone, a tablet computer, a television, a display, a laptop computer, a digital photo frame, a navigator, etc.

In the description of the present disclosure, it should be understood that an orientation or positional relation indicated by the terms “middle”, “upper”, “lower”, “front”, “rear”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer” and the like is based on the orientation or positional relation shown in the accompanying drawings, which is only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have the specific orientation, or be constructed and operated in the specific orientation, and thus cannot be interpreted as a limitation on the present disclosure.

In the description of the embodiments of the present disclosure, it should be noted that unless otherwise clearly specified and defined, the terms “install”, “couple”, “connect” should be broadly interpreted, for example, a connection may be a fixed connection, or a detachable connection, or an integrated connection; it may be a mechanical connection or an electrical connection; it may be a direct connection, or may be an indirect connection through an intermediary, or may be an internal connection between two elements. Those of ordinary skill in the art may understand the meanings of the terms in the present disclosure according to specific situations.

Although the embodiments disclosed in the present disclosure are as described above, the content described is only the embodiments used to facilitate the understanding of the present disclosure, and is not intended to limit the present disclosure. Anyone skilled in the art to which the present disclosure belongs can make any modifications and changes in the implementation forms and details without departing from the spirit and scope disclosed in the present disclosure. However, the scope of patent protection of the present disclosure is still subject to the scope defined by the appended claims.