An OLED panel that avoids color mixing during evaporation and a method for preparing the same

Abstract

The present invention provides an OLED panel that avoids color mixing during evaporation and a preparation method thereof, the OLED panel comprising: a substrate, including a pixel definition layer, the pixel definition layer including a plurality of pixel areas, the pixel area including a plurality of different sub-pixel areas; an organic functional layer; a support layer, including a plurality of support blocks arranged outside the sub-pixel area on the substrate; and a substrate material layer, arranged around each sub-pixel color area, to isolate two adjacent sub-pixel areas. The OLED panel provided by the present invention can effectively avoid the gaseous organic material from shifting to the heterochromatic sub-pixel area by arranging the substrate material layer on the pixel definition layer to separate the different sub-pixel areas on the pixel definition layer, thereby avoiding the color mixing of organic materials in different sub-pixel areas, and improving the yield rate and display quality of the OLED panel. The substrate material layer is arranged on the substrate, and there is no gap between it and the substrate, which more effectively avoids the offset and color mixing of heterochromatic organic materials.

Description

Technical Field

[0001] The present invention relates to the technical field of OLED panels, and in particular to an OLED panel that avoids color mixing during evaporation and a preparation method thereof. Background Art

[0002] During the evaporation process of AMOLED panels, a fine metal mask (FMM) is used to define the coating range of the R / G / B organic layers. During the evaporation process, the coating will produce a shadow effect due to the poor matching relationship between the evaporation angle of the evaporator and the FMM taper angle. For example, when the evaporated R color organic material is offset, the coating shadow part may shift to the G&B color, causing the risk of color mixing.

[0003] The current practice is to prevent color mixing by aligning the space during the vapor deposition process, and to keep the openings on the precision metal mask accurately aligned with the different color areas of the pixel definition layer on the LTPS substrate. However, in the edge area of ​​the LTPS substrate, the coating Shadow effect is more serious. When the organic material coating is offset, the organic material Shadow part can easily shift to the different color PDL, causing color mixing.

[0004] In the prior art, some technicians have modified the precision metal mask and set a retaining wall around the evaporation opening on the precision metal mask. During the evaporation process, the retaining wall is in contact with the LTPS substrate to ensure that the organic material is in the cavity formed by the precision metal mask, the retaining wall and the LTPS substrate, thereby avoiding offset and color mixing of the organic material. However, during the evaporation process of the organic material, if there is a certain gap between the retaining wall and the LTPS substrate, there is still a certain risk of color mixing. Summary of the invention

[0005] To solve the above problems in the prior art, the present invention provides an OLED substrate and a preparation method thereof, in which a substrate material layer is arranged on a substrate to prevent the deviation of organic materials in different pixel areas during evaporation and avoid color mixing.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A first aspect of the present invention is to provide an OLED panel that avoids color mixing during evaporation, comprising:

[0008] A substrate, comprising a pixel definition layer, the pixel definition layer comprising a plurality of pixel regions, and the pixel region comprising a plurality of different sub-pixel regions;

[0009] Organic functional layer;

[0010] A support layer, comprising a plurality of support blocks disposed outside the sub-pixel region on the substrate; and

[0011] The substrate material layer is arranged around each sub-pixel color area to isolate two adjacent sub-pixel areas.

[0012] Furthermore, each sub-pixel region corresponds to a different color in a color system.

[0013] Furthermore, the organic functional layer includes, from bottom to top, a hole injection layer, a hole input layer, an organic light emitting layer, an electron transport layer and an electron injection layer.

[0014] Furthermore, the sub-pixel region is rectangular, and the substrate material layer includes:

[0015] A first blocking block is arranged along one side of the rectangle formed by the sub-pixel areas;

[0016] A second blocking block is arranged along the opposite side of the rectangle formed by the sub-pixel areas and parallel to the first blocking block;

[0017] A third blocking block is disposed along a side of the rectangle formed by the sub-pixel areas and perpendicular to the first blocking block; and

[0018] The fourth blocking block is arranged along the opposite side of the rectangle formed by the sub-pixel areas and parallel to the third blocking block.

[0019] Furthermore, the material of the substrate material layer is a photoreactive material.

[0020] Furthermore, the material of the substrate material layer is positive photoresist.

[0021] Furthermore, the substrate material layer is flush with the top surface of the support layer.

[0022] A second aspect of the present invention is to provide a method for preparing the above-mentioned OLED panel, comprising the following steps:

[0023] S00, preparing a substrate material layer on a substrate;

[0024] S01, using a precision metal mask to vapor-deposit a color in a sub-pixel region on a pixel definition layer;

[0025] Wherein, the support layer and the substrate material layer support the precision metal mask;

[0026] The substrate material layer isolates the colors in different sub-pixel areas.

[0027] Furthermore, the method for preparing the substrate material layer in S00 includes: depositing a film on the substrate using a chemical vapor deposition method; then exposing the film, and finally developing it to complete the preparation.

[0028] Furthermore, the evaporation in s01 includes:

[0029] Providing a precision metal mask, on which a vapor deposition opening corresponding to the sub-pixel area is disposed;

[0030] The precision metal mask is arranged below the substrate, the evaporation opening corresponds to the sub-pixel area, and the precision metal mask is in contact with the substrate material layer and the support layer;

[0031] The organic material is heated to sublime or melt and evaporate, and is deposited on the sub-pixel region through the evaporation opening.

[0032] Furthermore, the size of the evaporation opening is equal to or larger than the size of the sub-pixel area.

[0033] The present invention adopts the above technical solution, which has the following technical effects compared with the prior art:

[0034] The present invention provides an OLED panel that avoids color mixing during evaporation and a preparation method thereof. A substrate material layer is arranged on the pixel definition layer of the substrate to separate different sub-pixel areas in the pixel area on the pixel definition layer. During the evaporation process, the gaseous organic material can be effectively prevented from shifting to the heterochromatic sub-pixel area due to the shadow effect, thereby avoiding the color mixing of organic materials in different sub-pixel areas, and improving the yield rate and display quality of the OLED panel; wherein the substrate material layer is arranged to be flush with the top surface of the support layer, which can assist the support layer in supporting the precision metal mask. The advantage of the OLED panel provided by the present invention over the setting of retaining walls on the precision metal mask to avoid color mixing of different sub-pixel areas is that the substrate material layer is arranged on the substrate, and there is no gap between it and the substrate, which more effectively avoids the offset and color mixing of heterochromatic organic materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the principle of color mixing caused by the offset of organic materials in different sub-pixel areas of a substrate during evaporation in the prior art;

[0036] Figure 2 A schematic structural diagram of an OLED panel for preventing color mixing during evaporation provided by an embodiment of the present invention;

[0037] Figure 3 A schematic diagram of the principle of the substrate in the evaporation process of an OLED panel for avoiding color mixing during evaporation provided by an embodiment of the present invention;

[0038] Figure 4 A schematic diagram of a substrate material layer and a sub-pixel region in an OLED panel for preventing color mixing during evaporation provided by an embodiment of the present invention;

[0039] Figure 5 A schematic diagram of a substrate material layer and a sub-pixel region in an OLED panel for preventing color mixing during evaporation provided by an embodiment of the present invention;

[0040] Figure 6A schematic diagram of a substrate material layer and a support layer in an OLED panel to prevent color mixing during evaporation provided by an embodiment of the present invention;

[0041] The figure numbers therein are: 10-substrate, 11-R color zone, 111-offset color mixing zone, 12-G color zone, 13-B color zone, 20-organic functional layer, 21-hole injection layer, 22-hole transport layer, 23-light-emitting layer, 24-electron transport layer, 25-electron injection layer, 30-cathode, 40-precision metal mask, 41-evaporation opening, 50-substrate material layer, 60-support layer. DETAILED DESCRIPTION

[0042] The present invention is described in detail and specifically by specific examples below to provide a better understanding of the present invention, but the following examples do not limit the scope of the present invention.

[0043] like Figure 1 As shown, in the prior art, during the evaporation process of the AMOLED panel, a precision metal mask 40 is used to define the range of the organic layer coating in different color areas of the pixel definition layer on the substrate 10. Generally, the evaporation opening 41 on the precision metal mask 40 is precisely aligned with the different sub-pixel areas of the pixel definition layer on the substrate 10 to achieve precise evaporation. However, when the positioning angle between the precision metal mask 40 and the different sub-pixel areas on the substrate 10 is not good, the position of the evaporation opening 41 and the different color areas will be offset. At this time, the organic layer will be offset and mixed between the different sub-pixel areas on the pixel definition layer. For example, the organic matter in the R color area 11 will be offset to the G color area 12, forming an offset mixed color area 111, causing the pixel definition layer to be mixed, affecting the display quality of the OLED panel and causing product losses.

[0044] like Figure 2 and Figure 3 As shown, the present invention provides an OLED panel that avoids color mixing during evaporation, including a substrate 10 and an organic functional layer 20; the substrate 10 has a pixel definition layer, the pixel definition layer includes a plurality of pixel areas, and a pixel area includes a plurality of different sub-pixel areas. The substrate 10 can select different substrate substrates according to needs, such as LTPS substrates, or other OLED panel substrates in the prior art.

[0045] Specifically, each sub-pixel area corresponds to a different color in a color system. The color system can be selected according to different OLED panel requirements, for example, it can be selected as an RGB color system, a CMYK color system, a YIQ color system or a YCbCr color system, etc. All color systems of OLED panels that can be prepared by evaporation are within the scope of the present invention. In a preferred embodiment of the present invention, the color system selects the RGB color system, and the sub-pixel areas in each pixel area are respectively the R color area 11, the G color area 12 and the B color area 13.

[0046] The organic functional layer 20 includes a hole injection layer 21, a hole transport layer 22, an organic light emitting layer 23, an electron transport layer 24 and an electron injection layer 25 from bottom to top, that is, in a direction away from the substrate 10. The anode of the OLED panel is arranged in the substrate 10, and the cathode 30 is arranged on the organic functional layer to supply power to the organic functional layer 20.

[0047] The substrate 10 further includes a support layer 60 and a substrate material layer 50. The support layer 60 includes a plurality of support blocks disposed on the substrate 10 except for the sub-pixel region; the substrate material layer 50 is disposed around each sub-pixel region to isolate two adjacent sub-pixel regions.

[0048] Among them, Figure 6 As shown, the support block included in the support layer 60 is flush with the top surface of the substrate material layer 50. The support layer 60 is used to support the precision metal mask 40, and at the same time plays a role in controlling the thickness between substrates and the uniformity of the substrate thickness. It contacts the precision metal mask 40 during the evaporation process of the substrate 10. The substrate material layer 50 is flush with the top surface of the support layer 60. During the evaporation process, the substrate material layer 50 and the support layer 60 are both in contact with the precision metal mask 40, and together play the role of supporting the precision metal mask 40, which can prevent the precision metal mask 40 from being deformed, and at the same time ensure the uniformity of the thickness of the substrate 10.

[0049] The support layer 60 can be selected from a photo spacer and is disposed on the substrate 10 by photolithography. Its shape and height can be selected according to the needs of the manufacturer. The support layer 60 can also be selected from other forms of spacers, all of which are included in the scope of the present invention.

[0050] like Figure 4 As shown, taking the RGB color system as an example, each sub-pixel area is a rectangle, and the substrate material layer 50 includes a first blocking block, a second blocking block, a third blocking block and a fourth blocking block arranged at intervals on the periphery of the four sides of the rectangle formed by the sub-pixel area. Among them, the first blocking block is arranged along one side of the rectangle formed by the sub-pixel area; the second blocking block is arranged along the opposite side of the rectangle formed by the sub-pixel area parallel to the first blocking block; the third blocking block is arranged along the side of the rectangle formed by the sub-pixel area perpendicular to the first blocking block; the fourth blocking block is arranged along the opposite side of the rectangle formed by the sub-pixel area parallel to the third blocking block. The four blocking blocks isolate two adjacent different sub-pixel areas, for example, in the RGB color system, separate the R color area 11 and the G color area 12.

[0051] It is obvious that the four corners of the periphery of adjacent sub-pixel areas are not separated, and it is possible that color mixing between different sub-pixel areas will still occur during the evaporation process. But in fact, this risk can be avoided by accurately aligning the evaporation opening 41 on the precision metal mask 40 with the sub-pixel area that needs to be evaporated. When the alignment is offset, generally only a small offset of the evaporation opening 41 relative to the sub-pixel area will occur, and the risk of color mixing will occur at the edge of the sub-pixel area. If the four corners of the sub-pixel area are offset, the evaporation opening 41 has already been offset in two directions with respect to the sub-pixel area, and this large offset can be avoided by precise alignment. The small offset can be blocked by the first blocking block, the second blocking block, the third blocking block and the fourth blocking block to avoid the risk of color mixing at the edge of the sub-pixel area. Therefore, by setting a discontinuous substrate material layer 50 on the periphery of the four sides of the rectangle formed by the sub-pixel area, the color mixing at the edge of the sub-pixel area can be avoided, and the material of part of the substrate material layer 50 can be saved, which is more economical.

[0052] like Figure 5 As shown, the sub-pixel area is in a rectangular shape, the substrate material layer 50 is continuously arranged on the periphery of the rectangle formed by the sub-pixel area, and the first blocking block, the second blocking block, the third blocking block and the fourth blocking block are continuously arranged to form a rectangular wall. The substrate material layer 50 arranged as a rectangular wall can isolate each adjacent sub-pixel area in all directions, and can completely avoid the risk of color mixing that may occur at the edges and corners of the sub-pixel area.

[0053] The material of the substrate material layer 50 is a photoreactive material, which is prepared on the pixel definition layer of the substrate 10 by chemical vapor deposition (CVD). In a preferred embodiment of the present invention, the material of the substrate material layer 50 is a positive photoresist.

[0054] The present invention also provides a method for preparing an OLED panel that avoids color mixing during evaporation as described above, the method comprising the following steps:

[0055] S00, preparing a substrate material layer 50 on a substrate 10;

[0056] S01, using a precision metal mask 40 to vapor-deposit a color in a sub-pixel region on a pixel definition layer;

[0057] The support layer 60 and the substrate material layer 50 are in contact with and support the precision metal mask 40 during the evaporation process; the substrate material layer 50 isolates organic materials of different colors in different sub-pixel regions during the evaporation process.

[0058] The arrangement of other components in the substrate 10, the organic functional layer 20 and the cathode 30 is the same as the preparation method in the prior art and will not be described again here.

[0059] In S00, the preparation of the substrate material layer 50 on the substrate 10 specifically includes: firstly, a layer of photoreactive material is deposited on the substrate 10 by CVD, then the layer of photoreactive material is exposed through a photomask, the part to be formed into the substrate material is not exposed to light, and the remaining part is exposed to light to react, and finally the photoreactive material exposed to light is dissolved by a developer, leaving the part not exposed to light to form the substrate material layer 50, and the preparation is completed. The shape of the photomask matches the shape of the required substrate material layer 50.

[0060] like Figure 3 As shown, S01 specifically includes:

[0061] A precision metal mask 40 is provided, and a vapor deposition opening 41 corresponding to the sub-pixel area is disposed on the precision metal mask 40;

[0062] The precision metal mask 40 is disposed below the substrate 10 , the evaporation opening 41 corresponds to the sub-pixel region, and the precision metal mask 40 is in contact with the substrate material layer 50 and the support layer 60 ;

[0063] The organic material is heated to sublime or melt and evaporate, and is deposited on the corresponding sub-pixel region through the evaporation opening 41 .

[0064] The size of the evaporation opening 41 is equal to or larger than the size of the sub-pixel area, thereby ensuring that the gaseous organic material can be completely deposited on the sub-pixel area through the evaporation opening 41 .

[0065] The beneficial effects of the present invention are as follows: by setting a substrate material layer 50 on the pixel definition layer of the substrate 10, different sub-pixel areas on the pixel definition layer are separated, and during the evaporation process, color mixing caused by factors such as shadow effect or offset between the evaporation opening 41 on the precision metal mask 40 and the sub-pixel area is avoided. Compared with setting a retaining wall on the precision metal mask 40 to separate different sub-pixel areas on the pixel definition layer, the present invention directly sets the substrate material layer 50 on the substrate 10. During the evaporation process, there is no gap between the substrate material layer 50 and the pixel definition layer, and the adjacent sub-pixel areas can be completely separated, thereby avoiding color mixing between different sub-pixel areas (such as the R color area 11 and the G color area 12). In addition, the top of the substrate material layer 50 and the support layer 60 on the substrate 10 in the present invention are flush, which can cooperate to support the precision metal mask 40 during the evaporation process and control the substrate thickness and uniformity at the same time.

[0066] The specific embodiments of the present invention are described in detail above, but they are only examples, and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions made to the present invention are also within the scope of the present invention. Therefore, the equalization changes and modifications made without departing from the spirit and scope of the present invention should be included in the scope of the present invention.

Claims

1. An OLED panel that avoids color mixing during evaporation, characterized in that: include: A substrate, comprising a pixel definition layer, wherein the pixel definition layer comprises a plurality of pixel regions, and the pixel regions comprise a plurality of different sub-pixel regions; Organic functional layer; A support layer, comprising a plurality of support blocks disposed outside the sub-pixel region on the substrate; and A substrate material layer is disposed around each of the sub-pixel regions to isolate two adjacent sub-pixel regions; The substrate material layer is flush with the top surface of the support layer; The sub-pixel area is in a rectangular shape, and the substrate material layer includes: A first blocking block is arranged along one side of the rectangle formed by the sub-pixel area; A second blocking block is arranged along an opposite side of a rectangle formed by the sub-pixel areas and parallel to the first blocking block; A third blocking block is disposed along a side of the rectangle formed by the sub-pixel areas and perpendicular to the first blocking block; and A fourth blocking block is arranged along an opposite side of the rectangle formed by the sub-pixel areas and parallel to the third blocking block; The first blocking block, the second blocking block, the third blocking block and the fourth blocking block are continuously arranged to form a rectangular wall.

2. The OLED panel according to claim 1, characterized in that: Each of the sub-pixel regions corresponds to a different color in a color system.

3. The OLED panel according to claim 1, characterized in that: The material of the substrate material layer is a photoreactive material.

4. The OLED panel according to claim 1, characterized in that: The material of the substrate material layer is positive photoresist.

5. A method for preparing an OLED panel according to any one of claims 1 to 4, characterized in that: The steps include: S00, preparing the substrate material layer on the substrate; S01, using a precision metal mask to evaporate and form color in the sub-pixel area on the pixel definition layer; Wherein, the support layer and the substrate material layer support the precision metal mask; The substrate material layer isolates the colors in different sub-pixel areas.

6. The preparation method according to claim 5, characterized in that: The method for preparing the substrate material layer in S00 includes: forming a film by chemical vapor deposition on the substrate; then exposing the formed film, and finally developing it to complete the preparation.

7. The preparation method according to claim 5, characterized in that: The evaporation in S01 includes: Providing a precision metal mask, wherein the precision metal mask is provided with an evaporation opening corresponding to the sub-pixel area; The precision metal mask is disposed below the substrate, the evaporation opening corresponds to the sub-pixel area, and the precision metal mask is in contact with the substrate material layer and the support layer; The organic material is heated to make it sublime or melt and evaporate, and then deposited on the sub-pixel area through the evaporation opening.

8. The preparation method according to claim 7, characterized in that: The size of the evaporation opening is equal to or larger than the size of the sub-pixel area.

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