Detailed Description
In the drawings, the thickness of layers, films, panels, regions, etc. have been exaggerated for clarity. Like reference numerals refer to like elements throughout the specification. It will be understood that when an element such as a layer, film, region or substrate is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element, there are no intervening elements present. As used herein, "connected" may refer to physical and/or electrical connections. Further, "electrically connected" or "coupled" may mean that there are additional elements between the two elements.
It will be understood that, although the terms first, second, third, etc. may be used herein to describe various components, elements, regions, layers and/or sections, these components, elements, regions, and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a "first component," "member," "region," "layer" or "portion" discussed below could be termed a second component, member, region, layer or portion without departing from the teachings herein.
Unless defined otherwise, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present invention and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Fig. 1A to fig. 1F are schematic cross-sectional views illustrating a manufacturing process of a display panel according to an embodiment of the invention. Fig. 2A is a partial top view of a display panel before a plurality of dielectric patterns are disposed thereon according to an embodiment of the invention. Fig. 2B is a partial top view of a display panel according to an embodiment of the invention.
Fig. 2A and 2B schematically illustrate only some of the members for convenience of explanation and observation. In the present embodiment, the display panel 10 (shown in fig. 1F) includes a substrate 100, an active device layer 120, an insulating layer 140, a plurality of first electrodes 150, a plurality of dielectric patterns 160, a plurality of organic light emitting patterns 200, and a second electrode 180. The method of making the panel 10 will be apparent from an example.
Referring to fig. 1A, a substrate 100 is provided. The substrate 100 may be made of glass, quartz, organic polymer, opaque/reflective material (e.g., conductive material, metal, wafer, ceramic, or other suitable material) or other suitable material. If a conductive material or metal is used, an insulating material (not shown) is coated on the substrate 100 to avoid the short circuit problem.
Next, an active device layer 120 is disposed on the substrate 100. The active device layer 120 may be, for example, an active device array (not shown), wherein the active device array includes a plurality of Thin Film Transistors (TFTs) (not shown). The thin film transistor is, for example, a low temperature polysilicon thin film transistor (LTPS) or an amorphous silicon thin film transistor (a-Si), but the invention is not limited thereto.
Next, an insulating layer 140 is disposed on the active device layer 120. The insulating layer 140 has a plurality of first regions 12 and a second region 14 between the first regions 12. In the present embodiment, the material of the insulating layer 140 includes an inorganic material. The inorganic material includes silicon nitride (SiNx) or other suitable materials, but the invention is not limited thereto.
Then, a plurality of first electrodes 150 are disposed on the insulating layer 140. The first electrodes 150 are separated from each other and respectively located on the first regions 12. Referring to fig. 1A and fig. 2A, in the present embodiment, each first electrode 150 is disposed on each first region 12, and the plurality of first regions 12 are separated by the second regions 14 to be independent from each other. In the present embodiment, each of the first electrodes 150 is disposed in the corresponding first region 12 independently and arranged in an array manner, but the invention is not limited thereto. In other embodiments, each of the first electrodes 150 may also be arranged in a pre-designed pattern.
In one embodiment, the first electrode 150 may be a single layer, a double layer, or a multi-layer structure. The material of the first electrode 150 may be a conductor material, for example: aluminum (Al), silver (Ag), chromium (Cr), copper (Cu), nickel (Ni), titanium (Ti), molybdenum (Mo), magnesium (Mg), platinum (Pt), gold (Au), and the like, or, for example, may be a metal oxide such as: indium tin oxide, indium zinc oxide, aluminum tin oxide, aluminum zinc oxide, indium gallium oxide, or other suitable materials, or a stack of at least two of the foregoing. For example, the first electrode 150 may be a three-layer structure composed of ITO/Ag/ITO, but the invention is not limited thereto. In other embodiments, the first electrode 150 may also be a three-layer structure of Ti/Al/Ti or Mo/Al/Mo. In some embodiments, the first electrode 150 may be formed by Chemical Vapor Deposition (CVD), Physical Vapor Deposition (PVD), Atomic Layer Deposition (ALD), evaporation (VTE), Sputtering (SPT), or a combination thereof. In some embodiments, the first electrode 150 may serve as an anode (anode) of the organic light emitting pattern 200, but the present invention is not limited thereto.
Referring to fig. 1B and fig. 2A, a plurality of dielectric layers 160 are disposed on the first electrodes 150. For example, the dielectric patterns 160 partially overlap the first electrodes 150 in a direction perpendicular to the substrate 100, and a portion of the dielectric patterns 160 is located in the second region 14. The dielectric patterns 160 are separated from each other and have a plurality of openings 162. The openings 162 are located in the first region 12 and respectively overlap with the corresponding first electrodes 150 in a direction perpendicular to the substrate 100. Specifically, the openings 162 expose the first electrodes 150. In the present embodiment, the gap D between the dielectric patterns 160 overlaps the second region 14 of the insulating layer 140, and the gap D exposes the insulating layer. In the present embodiment, the dielectric pattern 160 is formed by, for example, first forming a dielectric material (not shown) on the insulating layer 140 and covering the first electrode 150. The dielectric material is patterned by, for example, photolithography to form a plurality of separated dielectric patterns 160 and corresponding openings 162, but the invention is not limited thereto.
Please refer to fig. 1C, a surface treatment 300 is performed on the insulating layer 140 exposed in the gap D. For example, the step of performing the surface treatment 300 includes performing a plasma treatment on the insulating layer 140 using tetrafluoromethane (CF4) as a working gas. In the present embodiment, after the step of performing the surface treatment 300, the insulating layer 140 exposed in the gap D has a high contact angle with respect to Propylene Glycol Methyl Ether Acetate (PGMEA), and the contact angle is greater than 40 °. In other words, the insulating layer 140 exposed by the gap D has a hydrophobic and/or ink-repellent property. Specifically, the exposed insulating layer 140 has a hydrophobic surface. Thus, compared to the conventional method of forming the accommodating space for defining the pixel structure by the retaining wall structure, the present embodiment does not need to provide the retaining wall structure for accommodating the organic light emitting pattern 200 formed subsequently, and can define the pixel structure and avoid mixing or color mixing of the organic light emitting patterns 200 on the adjacent dielectric patterns 160.
Next, referring to fig. 1D, fig. 1E and fig. 2B, a plurality of organic light emitting patterns 200 are disposed on the dielectric pattern 160 and in the openings 162, respectively. Referring to fig. 1D, in the present embodiment, in order to increase the material utilization rate and reduce the manufacturing cost of the display panel 10, the organic light emitting pattern 200 may be formed by an Ink Jet Printing (IJP) process. For example, the organic light emitting material 200' may be disposed on the dielectric pattern 160 and in the opening 162 and contact the first electrode 150 by an inkjet coating process. The organic light emitting material 200' is, for example, a liquid material of the organic light emitting pattern 200 as a pixel.
Then, referring to fig. 1D, fig. 1E and fig. 2, the liquid organic light emitting material 200' is dried by a curing process (not shown) to form the solid organic light emitting pattern 200. In some embodiments, the organic light emitting pattern 200 may be a multi-layer structure including a Hole Injection Layer (HIL), a Hole Transfer Layer (HTL), and a light Emitting Layer (EL). FIG. 1E is shown in a single layer configuration for ease of illustration and clarity.
In some embodiments, the hole injection layer is made of a material such as copper phthalocyanine, star-like arylamines, polyaniline, polyethylene dioxythiophene, or other suitable materials. The material of the hole transport layer is, for example, a triarylamine, a cross-structure diaminobiphenyl, a diaminobiphenyl derivative, or other suitable materials. The light emitting layer may be a red organic light emitting pattern, a green organic light emitting pattern, a blue organic light emitting pattern, or a light emitting pattern of different colors (e.g., white, orange, yellow, etc.) generated by mixing light of respective spectrums.
It is to be noted that the difference between the surface tension of the liquid and the adsorption force of the dam structure causes the uneven film thickness during the drying process of the liquid droplet, so the thickness of the organic light emitting pattern formed by the above conventional process increases as approaching the dam structure, resulting in uneven film thickness. Since the display panel 10 according to an embodiment of the present invention arranges the dielectric pattern 160 on the first electrode 150, the PGMEA contact angle of the dielectric pattern 160 is less than 10 °. In other words, the dielectric pattern 160 has hydrophilicity and/or ink affinity. Accordingly, the droplet-shaped organic light emitting material 200' may be adsorbed onto the dielectric pattern 160 and fixed to the dielectric pattern 160 through the hydrophobic and/or ink-repellent insulating layer 140. Thus, the present embodiment can define a plurality of pixel structures without the conventional dam structure for accommodating the organic light emitting materials 200'. Therefore, the dielectric patterns 160 can prevent the organic light emitting patterns 200 on the adjacent dielectric patterns 160 from mixing or color mixing, and further improve the aperture ratio of the display panel 10 and the display quality. In addition, since the present embodiment does not need to provide a conventional dam structure, the film thickness of the organic light emitting pattern 200 formed after curing the organic light emitting material 200' can be uniform and uniform, so as to provide uniform brightness and good display quality.
Referring to fig. 1F and fig. 2B, fig. 1F is a schematic cross-sectional view of the display panel 10 of fig. 2B along a sectional line a-a'. Then, the second electrode 180 is disposed on the organic light emitting pattern 200. In this embodiment, before the step of disposing the second electrode 180, an electron transport layer 170 may be further disposed between the organic light emitting pattern 200 and the second electrode 180. The electron transport layer 170 is formed on the organic light emitting pattern 200 by a thermal evaporation process, for example, to reduce the driving voltage of the organic light emitting pattern 200. The electron transport layer 170 is disposed on the insulating layer 140, covers the dielectric pattern 160, and contacts the insulating layer 140 exposed by the gap D in the second region 14. In the present embodiment, the material of the electron transport layer may be an oxazole derivative and its dendrimer, a metal chelate compound (e.g., Alq3), an azole compound, a diazaanthracene derivative, a silicon-containing heterocyclic compound, or other suitable materials.
In the embodiment, the second electrode 180 may be disposed on the organic light emitting pattern 200 in a full-surface manner and overlap the dielectric pattern 160, the organic light emitting pattern 200 and the first electrode 150, but the invention is not limited thereto. The material of the second electrode 180 may be a transparent conductor material, such as metal oxide, e.g., indium tin oxide, indium zinc oxide, aluminum tin oxide, aluminum zinc oxide, or indium germanium zinc oxide. In some embodiments, the second electrode 180 may be formed by Chemical Vapor Deposition (CVD), Physical Vapor Deposition (PVD), Atomic Layer Deposition (ALD), evaporation (VTE), Sputtering (SPT), or a combination thereof. In some embodiments, the second electrode 180 may serve as a cathode (cathode) of the organic light emitting pattern 200.
In short, in the display panel 10 according to an embodiment of the invention, the dielectric patterns 160 are disposed on the first electrode 150, and the dielectric patterns 160 are hydrophilic and/or ink-repellent, while the insulating layer 140 exposed by the gaps D between the dielectric patterns 160 can be made hydrophobic and/or ink-repellent by the surface treatment 300. Therefore, the droplet-shaped organic light emitting material 200' may be adsorbed onto the dielectric pattern 160 and fixed on the dielectric pattern 160 by being pushed away by the hydrophobic and/or ink-repellent properties of the gap D of the insulating layer 140. Thus, the display panel 10 can define a plurality of pixel structures without using a conventional barrier structure to accommodate the organic light emitting materials 200'. Therefore, the dielectric patterns 160 can prevent the organic light emitting patterns 200 on the adjacent dielectric patterns 160 from mixing or color mixing, and can improve the aperture ratio of the display panel 10 and the display quality. In addition, the process of the display panel 10 can be simplified and the manufacturing cost can be reduced. In addition, since the present embodiment does not need to provide a conventional retaining wall structure, the film thickness of the organic light emitting pattern 200 formed after curing the organic light emitting material 200' can be uniform and uniform, so that the display panel 10 can provide uniform brightness and good display quality.
Structurally, referring to fig. 1F and 2B, the display panel 10 includes a substrate 100, an active device layer 120 disposed on the substrate 100, an insulating layer 140 disposed on the active device layer 120, a plurality of first electrodes 150, a plurality of dielectric patterns 160, a plurality of organic light emitting patterns 200, and a second electrode 180 disposed on the organic light emitting patterns 200. The insulating layer 140 has a plurality of first regions 12 and a second region 14 between the first regions 12. The first electrodes 150 are separated from each other and disposed on the first regions 12 of the insulating layer 140, respectively. The dielectric patterns 160 are separated from each other and disposed on the first electrodes 150, respectively, and have a plurality of openings 162. The openings 162 overlap the first electrodes 150 in a direction perpendicular to the substrate 100. The organic light emitting patterns 200 are disposed on the dielectric patterns 200 and in the openings 162, respectively, and the gap D between the dielectric patterns overlaps with the second region 14 of the insulating layer 140. The second electrode 180 is disposed on the organic light emitting pattern 200. In this embodiment, the display panel 10 further includes an electron transport layer 170 disposed between the organic light emitting pattern 200 and the second electrode 180. The electron transport layer 170 contacts the insulating layer 140.
Referring to fig. 1F, fig. 2A and fig. 2B, in the present embodiment, an orthogonal projection of each first electrode 150 on the substrate 100 is surrounded by an orthogonal projection of each dielectric pattern 160 on the substrate 100. In other words, a portion of the dielectric pattern 160 may overlap and contact the first electrode 150, and another portion may overlap and contact the insulating layer 140. In addition, the organic light emitting pattern 200 overlaps the dielectric pattern 160. The orthographic projection outer edge of the dielectric pattern 160 on the substrate 100 is surrounded by the orthographic projection edge of the organic light-emitting pattern 200 on the substrate 100. The organic light emitting pattern 200 contacts the insulating layer 140 in the gap D. Under the above arrangement, the organic light emitting pattern 200 may be fixed to the dielectric pattern 160. Thus, the display panel 10 can define a plurality of pixel structures without using a conventional barrier structure, and can prevent the mixing or color mixing of the adjacent organic light emitting patterns 200, thereby improving the display quality. In addition, since the conventional dam structure is not required in the embodiment, the film thickness of the organic light emitting pattern 200 may be uniform and uniform, so that the display panel 10 may provide uniform brightness and good display quality.
In the present embodiment, the distance W1 from the edge of the opening 162 to the second region 14 in the direction perpendicular to the substrate 100 is greater than or equal to 1 micron and less than or equal to 5 microns. Further, a distance W2 from the edge of the first electrode 150 to the outer edge of the dielectric pattern 160 is 1 micron or more and 5 microns or less. Under the above configuration, the size of the opening 160 can be adjusted to increase the aperture ratio, and the distance between the adjacent organic patterns 200 can be further reduced to increase the number of pixel structures, thereby improving the display quality of the display panel 10.
In short, in the display panel 10 according to an embodiment of the invention, the dielectric patterns 160 are disposed on the first electrode 150, and the dielectric patterns 160 are hydrophilic and/or ink-repellent, while the insulating layer 140 exposed by the gaps D between the dielectric patterns 160 can be made hydrophobic and/or ink-repellent by the surface treatment 300. Accordingly, the organic light emitting pattern 200 may be fixed to the dielectric pattern 160. Thus, the display panel 10 can define a plurality of pixel structures without using a conventional dam structure, and can avoid mixing or color mixing of the adjacent organic light emitting patterns 200, thereby further improving the aperture ratio of the display panel 10 and the display quality. In addition, since the conventional dam structure is not required in the embodiment, the film thickness of the organic light emitting pattern 200 may be uniform and uniform, so that the display panel 10 may provide uniform brightness and good display quality.
The following embodiments follow the component reference numerals and part of the contents of the foregoing embodiments, wherein the same reference numerals are used to indicate the same or similar components, and for the part of the description where the same technical contents are omitted, reference may be made to the foregoing embodiments, and the description in the following embodiments is not repeated.
Fig. 3A is a schematic cross-sectional view of a display panel according to another embodiment of the invention. The display panel 10A shown in the present embodiment is similar to the display panel 10 shown in fig. 1F, and the main difference is that: the second region 14 of the insulating layer 140 has a protrusion 142A, and an orthogonal projection of the protrusion 142A on the substrate 100 is separated from an orthogonal projection of the first electrode 150 on the substrate 100. In the present embodiment, the protrusion structure 142A and the insulating layer 140 are the same film layer. For example, after the insulating layer 140 is formed, the insulating layer 140 may be patterned by photolithography to form the protrusion structure 142A in the second region 14. Under the above arrangement, the protrusion 142A may be formed between adjacent first electrodes 150 and assist the dielectric pattern 160 to define a plurality of pixel structures. Specifically, the protrusion structure 142A may further prevent the adjacent organic light emitting patterns 200 from mixing or color mixing due to the flow. In addition, the protrusion structure 142A is located in the second region 14 without the light emitting function between the first electrodes 150, and therefore, the aperture ratio of the display panel 10A is not affected. Thus, the display panel 10A can achieve similar technical effects as the above embodiments.
In the present embodiment, the height H1A of the protrusion structure 142A is greater than or equal to 0.1 micrometers and less than or equal to 10 micrometers. For example, the height H1A of the protrusion 142A is the height from the top surface 143A of the protrusion 142A to the surface of the insulating layer 140. With the above arrangement, the height H1A of the protrusion 142A can be adjusted to be similar to the thickness of the organic light emitting pattern 200. Therefore, the film thickness of the organic light emitting pattern 200 can be uniform, and the generation of leakage current can be reduced, so that the display panel 10 can provide uniform brightness and good display quality.
Fig. 3B is a schematic cross-sectional view of a display panel according to another embodiment of the invention. The display panel 10B shown in the present embodiment is similar to the display panel 10A shown in fig. 3A, and the main difference is that: the cross-sectional shape of the protruding structure 142B of the display panel 10B is circular arc, and the cross-sectional shape of the protruding structure 142A of the display panel 10A is trapezoid. Thus, the display panel 10B can achieve similar technical effects as the above embodiments.
In summary, in the display panel and the manufacturing method thereof according to the embodiment of the invention, the dielectric patterns are disposed on the first electrode, and the dielectric patterns have hydrophilic and/or ink-affinity, and the insulating layer exposed by the gaps between the dielectric patterns can have hydrophobic and/or ink-phobic properties by surface treatment. Accordingly, the organic light emitting pattern may be fixed to the dielectric pattern. Therefore, the display panel can define a plurality of pixel structures without the help of the traditional retaining wall structure, can avoid the mixing or color mixing of adjacent organic light-emitting patterns, can further improve the aperture opening ratio of the display panel and improve the display quality. In addition, since the conventional retaining wall structure is not required, the film thickness of the organic light emitting pattern can be consistent and uniform, so that the display panel can provide uniform brightness and good display quality. In addition, a protrusion structure may be formed between adjacent first electrodes to further avoid mixing or color mixing of adjacent organic light emitting patterns due to flow. In addition, the convex structure is positioned in the second area without the light emitting function between the first electrodes, so that the aperture opening ratio of the display panel is not influenced. In addition, the height of the protruding structure can be adjusted to be similar to the thickness of the organic light-emitting pattern. Therefore, the film thickness of the organic light-emitting pattern can be uniform, and the generation of leakage current can be reduced, so that the display panel can provide uniform brightness and good display quality.
Although the present invention has been described with reference to the above embodiments, it should be understood that the invention is not limited to the embodiments, and various changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention.