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EP-3240029-B1 - DISPLAY SUBSTRATE, MANUFACTURING METHOD AND DISPLAY DEVICE THEREOF

EP3240029B1EP 3240029 B1EP3240029 B1EP 3240029B1EP-3240029-B1

Inventors

  • WANG, HUIFENG
  • LIU, Ze

Dates

Publication Date
20260506
Application Date
20150421

Claims (6)

  1. A method for manufacturing a display substrate, comprising steps of: forming pixel partition walls(101,102) for defining pixel regions(200,201) of the display substrate; and forming display layers at the pixel regions(200,201) by inkjet printing, wherein the step of forming the pixel partition walls(101,102) comprises: forming first pixel partition walls (101) for defining first pixel regions(200) and second pixel partition walls(102) for defining second pixel regions(201), each first pixel partition wall(101) being of a height greater than each second pixel partition wall(102), and a plurality of adjacent second pixel regions(201) being located within an identical first pixel region(200), and the step of forming the display layers at the pixel regions(200,201) by inkjet printing comprises: inkjet printing an identical material at each first pixel region(200) by at least one nozzle(10, 11, 12), so as to form the identical display layer at the plurality of second pixel regions(201) within the first pixel region(200), the display layer being of a height greater than the height of each second pixel partition wall(102), characterized in that the step of forming the first pixel partition walls(101) and the second pixel partition walls(102) comprises: forming patterns of first layers(1011), the first layers(1011) being located at regions where the first pixel partition walls(101) and the second pixel partition walls(102) are located; and forming patterns of second layers(1012) on the first layers(1011), the second layers(1012) only being located at regions where the first pixel partition walls(101) are located; and wherein the display substrate is a color filter substrate, the first pixel partition walls (101) and the second pixel partition walls (102) are each made of resin, organic silicon or silicon dioxide, the first pixel partition walls (101) and the second pixel partition walls (102) form black matrices, and a sum of thicknesses of each first layer (1011) and each second layer (1012) is greater than a thickness of the display layer; wherein a short side of each first pixel region(200) extends in a row direction, the identical material is inkjet-printed at all the first pixel regions(200) in an identical column simultaneously by a sprayer(13) including a plurality of nozzles (10, 11, 12), and the sprayer(13) is moved in the row direction so as to inkjet print the corresponding material at the first pixel regions(200) in all the columns; wherein the identical material is inkjet-printed at each first pixel region (200) by at least two nozzles (10,11,12); wherein a width of the second layer (1012) in a direction parallel to the display substrate decreases gradually along a direction perpendicular to the display substrate; wherein the first layer(1011) is of a thickness of 10nm to 100µm; wherein the second layer(1012) is of a thickness of 100nm to 100µm.
  2. The method according to claim 1, wherein the first pixel regions(200) are each of a strip-like shape and arranged in a matrix form.
  3. A display substrate, wherein the display substrate is a color filter substrate, the display substrate comprising: pixel partition walls(101,102) for defining pixel regions(200,201) of the display substrate, the pixel partition walls(101,102) comprising first pixel partition walls(101) for defining first pixel regions(200) and second pixel partition walls(102) for defining second pixel regions(201), each first pixel partition wall(101) being of a height greater than each second pixel partition wall(102), a plurality of adjacent second pixel regions(201) being located at an identical first pixel region(200); an identical display layer formed at the plurality of second pixel regions(201) within each first pixel region(200), the display layer being of a height greater than the height of each second pixel partition wall(102), characterized in that each first pixel partition wall(101) comprises a first layer(1011) and a second layer(1012) on the first layer(1011), each second pixel partition wall(102) comprises the first layer(1011), the first pixel partition walls (101) and the second pixel partition walls (102) form black matrices, and a sum of thicknesses of the first layer (1011) and the second layer (1012) is greater than a thickness of the display layer; wherein the second layers(1012) are only located at regions where the first pixel partition walls(101) are located; wherein the first pixel partition walls (101) and the second pixel partition walls (102) are each made of resin, organic silicon or silicon dioxide, wherein a short side of each first pixel region(200) extends in a row direction, and the display layers at the first pixel regions(200) in an identical column are made of an identical material; wherein a width of the second layer (1012) in a direction parallel to the display substrate decreases gradually along a direction perpendicular to the display substrate; wherein the first layer(1011) is of a thickness of 10nm to 100µm; wherein the second layer(1012) is of a thickness of 100nm to 100µm.
  4. The display substrate according to claim 3, wherein the first pixel regions(200) are each of a strip-like shape and arranged in a matrix form.
  5. The display substrate according to claim 3 or 4, wherein three adjacent second pixel regions(201) are located at an identical first pixel region(200).
  6. A display device comprising the display substrate according to any one of claims 3 to 5.

Description

TECHNICAL FIELD The present disclosure relates to the field of display technology, in particular to a display substrate, its manufacturing method and a display device. BACKGROUND Organic light-emitting diode (OLED) display device has been considered as a next-generation display technology due to its advantages over a liquid crystal display, such as self-luminescence, rapid response, wide viewing angle, high brightness, vivid colors, light weight and thinness. As a main structure of the OLED display device, an OLED display substrate includes a plurality of pixel regions defined by a pixel definition layer, and each pixel region includes an OLED that emits a ray in a specific color, respectively. During the manufacture of the OLED display substrate, films of the OLED are mainly formed by an evaporation or solution process. The evaporation process has been widely used for the manufacture of a small-size display device. The solution process mainly includes inkjet printing, spaying, spinning, and screen printing. Due to a high material utilization rate and being applicable to a large-size product, the inkjet printing technique has been considered as an important way for the mass production of the large-size OLED display device. In order to improve the production efficiency, a sprayer of an inkjet printing device includes a plurality of nozzles, so as to form a plurality of display layers (e.g., an organic light-emitting layer) at pixel regions in an identical color. However, during the actual manufacture, it is impossible to fully ensure an even ink amount from the respective nozzles. Prior to the inkjet printing, it is required to precisely adjust the ink amount for each nozzle, so that an error among ink volumes from the nozzles in unit time is less than ±0.3%. When a larger error occurs, it is able for human's eyes to distinguish between pixels due to brightness differences caused by this error after the display device is lightened up. Hence, one of the core techniques for inkjet printing lies in how to provide an even inkjet amount for the pixels. As shown in Fig.1, pixel regions are arranged in a matrix form in the related art, and each pixel region is usually of a strip-like shape (e.g., a red pixel region 2, a red pixel region 3 and a blue pixel region 4). Currently, each sprayer 13 from a manufacturer is usually provided with 256 or 512 nozzles 1. Hence, for the mass production of a TV with a resolution of 3840*2160, when the sprayer 13 with 256 nozzles 1 is adopted, 5 sprayers 13 are required so as to print the 3840 display layers in an identical row and at pixel regions in an identical color, and then the 5 sprayers 13 are required to be moved simultaneously in a direction as shown by an arrow in Fig.1 so as to print the OLEDs in an identical color in all of the rows. Usually, it takes 3 to 5 hours to control a volume error for 256 nozzles 1 to be less than 0.3%, so it will take a very long time period to control the volume error for 1280 nozzles 1 to be less than 0.3%. In addition, after a certain period of time, it is required to re-adjust the ink volumes from the 1280 nozzles 1 at the expense of a lot of time and ink. In Fig.1, different grayscales represent different thicknesses of the display layers in the red pixel units 2. Moreover, JP 2005310713A disclose an organic light emitting device, wherein each unit pixel is divided into a plurality of light emitting parts 52R. The organic light emitting device includes barrier ribs B for partitioning the unit pixels by surrounding the plurality of light emitting parts 52R. US 2009/153044 A1 disclose an OLED display device including a substrate, a plurality of pixel electrodes arranged in a matrix on the substrate, and a counter electrode disposed opposite the plurality of pixel electrodes. US 2005/285509 A1 disclose an organic electroluminescent device, in which the organic electroluminescent device has an organic functional layer formed by a liquid phase method, the organic functional layer formed in a uniform thickness while maintaining an aperture ratio, thereby obtaining a uniform and high efficient emission. US 2006/0284957A1 disclose a color filter and manufacturing method therefor. JP 2008091070A disclose a light-emitting device and an electronic equipment. SUMMARY An object of the present disclosure is to provide a display substrate and its manufacturing method, as defined in the appended set of claims, so as to prevent the occurrence of uneven brightness due to different thicknesses of pixel layers for pixel units formed by inkjet printing. Another object of the present disclosure is to provide a display device, so as to prevent the display quality thereof from being seriously affected due to the uneven thicknesses of display layers. According to the embodiments of the present disclosure, the pixel partition walls of the display substrate include the first pixel partition walls for defining the first pixel regions and the second pixel partition