Display apparatus

Abstract

This invention provides a display device. The display device includes: a substrate comprising a plurality of sub-pixels; a thin-film transistor (TFT) located on the substrate; a planarization layer located on the TFT; an anode disposed on the planarization layer and for each sub-pixel; a light-emitting layer disposed on the anode; and a cathode located on the light-emitting layer. The planarization layer includes: a contact hole for connecting the anode and the TFT; and a trench portion located opposite the contact hole based on the anode.

Description

Technical Field

[0001] This invention relates to a display device, and more specifically, to a display device capable of improving brightness and viewing angle. Prior Technology

[0002] The field of display devices that visually represent electrical information signals is rapidly developing. Therefore, various studies are being conducted on display devices to improve performance, such as thin profile, brightness, and low power consumption.

[0003] Typical display devices include liquid crystal display (LCD) devices, field emission display (FED) devices, electrowetting display (EWD) devices, organic light emission display (OLED) devices, and the like.

[0004] Electroluminescent displays, including OLEDs, are self-emissive and, unlike LCDs, do not require a separate light source. Therefore, electroluminescent displays can be manufactured in thinner and lighter designs. Furthermore, electroluminescent displays not only offer advantages in terms of power consumption due to low-voltage operation but also boast superior color implementation, response speed, viewing angle, and contrast ratio (CR). Therefore, electroluminescent displays are expected to be used in a variety of fields. Summary of the Invention

[0005] The present invention provides a display device that is particularly capable of suppressing the degradation of the luminous efficacy and viewing angle of a light-emitting diode.

[0006] The present invention provides a display device that is particularly capable of suppressing asymmetric color shift (ASCS) that occurs when the azimuth angle is changed at the same viewing angle.

[0007] The present invention provides a display device that is particularly capable of suppressing brightness at low viewing angles.

[0008] The technical features of this invention are not limited to those mentioned above, and those skilled in the art will clearly understand other technical features not mentioned above from the following description.

[0009] A display device according to an exemplary embodiment of the present invention includes: a substrate comprising a plurality of sub-pixels; a thin-film transistor disposed on the substrate; a planarization layer disposed on the thin-film transistor; an anode disposed on the planarization layer and for each sub-pixel; a light-emitting layer disposed on the anode; and a cathode disposed on the light-emitting layer. The planarization layer includes: a contact hole for connecting the anode and the thin-film transistor; and a trench portion located opposite the contact hole based on the anode.

[0010] Further details of the exemplary embodiments are included in the detailed description and drawings.

[0011] According to the present invention, the display device includes an anode having a symmetrical shape in cross-section. Therefore, azimuth-dependent ASCS can be suppressed.

[0012] According to the present invention, the display device includes a trench portion symmetrical to the contact holes in the planarization layer. Therefore, the shape of the anode can be adjusted.

[0013] According to the present invention, the display device can improve luminous efficiency and viewing angle.

[0014] According to the present invention, the display device can improve the lifespan of the light-emitting diode.

[0015] The effects of the present invention are not limited to those exemplified above, and many more effects are included in this specification. Simple Explanation of the Diagram

[0016] The above and other aspects, features and advantages of the invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, wherein: Figure 1 is a plan view of a display device according to an exemplary embodiment of the present invention; Figure 2 is an enlarged plan view of the PX region in Figure 1; Figure 3 is a cross-sectional view taken along line I-I' in Figure 2; Figure 4 is a schematic cross-sectional view of an illustrative example of a display device; Figures 5A and 5B are diagrams illustrating the spherical coordinate system on the display device; Figure 6 is a plan view of a display device according to another exemplary embodiment of the present invention; Figure 7 is a cross-sectional view taken along line II-II' in Figure 6; Figure 8 is a cross-sectional view of a display device according to another exemplary embodiment of the present invention; Figure 9 is a plan view of a display device according to yet another exemplary embodiment of the present invention; Figure 10 shows schematic cross-sectional views of the light-emitting diodes of the display devices according to illustrative Example 1 and illustrative Example 2, respectively; and Figure 11 is a graph showing the ASCS measured depending on the viewing angle and azimuth angle in each of illustrative example 1, illustrative example 2 and embodiments of the present invention. Implementation

[0017] The advantages and features of the present invention, and the methods for achieving such advantages and features, will become clear from the exemplary embodiments described below in conjunction with the accompanying drawings. However, the present invention is not limited to the exemplary embodiments disclosed herein, and will be practiced in various ways. The exemplary embodiments are provided by way of example only, so that those skilled in the art can fully understand the content and scope of the present invention.

[0018] The shapes, dimensions, proportions, angles, quantities, and similarities illustrated in the accompanying drawings, used to describe exemplary embodiments of the present invention, are merely examples, and the invention is not limited thereto. Throughout the specification, similar reference numerals generally refer to similar elements. Furthermore, in the following description of the invention, detailed explanations of known related technologies may be omitted to avoid unnecessarily obscuring the subject matter. Terms such as "comprising," "including," "having," and "consisting of" as used herein are generally intended to allow for the addition of other components, unless these terms are used in conjunction with the term "only." Any reference to the singular may include the plural unless expressly stated otherwise.

[0019] Even if not explicitly stated, the component is interpreted as including a normal error range.

[0020] When using terms such as "above," "over," "below," and "beside" to describe the positional relationship between two parts, one or more parts may be located between the two parts, unless these terms are used with the terms "immediately" or "directly."

[0021] When an element or layer is placed "on" another element or layer, the element or layer may be directly on the other element or layer, or the other element or layer may be placed therebetween.

[0022] Although the terms "first," "second," and similar are used to describe various elements, these elements are not bound by these terms. These terms are only used to distinguish one element from other elements. Therefore, in the technical concept of the present invention, the first element mentioned below may be the second element.

[0023] Throughout the instruction manual, similar reference numbers generally refer to similar components.

[0024] For ease of description, the dimensions and thickness of each component shown in the figures are illustrated, but the invention is not limited to the dimensions and thickness of the components described.

[0025] The features of the various embodiments of the present invention can be partially or wholly attached to or combined with each other, and can be interlocked and operated in various technical ways, and the embodiments can be implemented independently or in conjunction with each other.

[0026] In the following, a display device according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0027] Figures 1 to 3 are diagrams used to explain a display device according to an exemplary embodiment of the present invention. Figure 1 is a plan view of a display device according to an exemplary embodiment of the present invention. Figure 2 is an enlarged plan view of the PX region of Figure 1. Figure 3 is a cross-sectional view taken along line I-I' of Figure 2.

[0028] Referring to FIG1, the display device 100 includes: a display area DA; and a non-display area NDA. The display area DA is an area in which a plurality of pixels PX are disposed to substantially display an image. Pixels PX including a light-emitting area for displaying the image and driving circuitry for driving the pixels PX may be disposed in the display area DA. The non-display area NDA surrounds the display area DA. The non-display area NDA is an area in which no image is substantially displayed. Furthermore, various lines, driver ICs, printed circuit boards, etc., for driving the pixels PX disposed in the display area DA and the driving circuitry are disposed in the non-display area NDA.

[0029] Referring to Figure 1, a plurality of pixels PX are disposed in the display area DA. The plurality of pixels PX are arranged in a matrix. Referring to Figure 2, each of the plurality of pixels PX includes a plurality of sub-pixels SP1, SP2, and SP3. Each of the sub-pixels SP1, SP2, and SP3 is an element for displaying a color and includes a light-emitting area that emits light and a non-light-emitting area that does not emit light. In this invention, the area where the light-emitting layer is disposed is called the light-emitting area, and the other area is called the non-light-emitting area.

[0030] Figure 2 illustrates the anodes 121a, 121b and 121c, the second contact holes CH2a, CH2b and CH2c, and the trench portions HP1, HP2 and HP3 constituting the first to third sub-pixels SP1, SP2 and SP3 of the display device 100.

[0031] A pixel PX may include: a first sub-pixel SP1; a second sub-pixel SP2; and a third sub-pixel SP3. For example, referring to FIG2, the first sub-pixel SP1 and the second sub-pixel SP2 may be disposed relative to each other in a second direction (e.g., the Y-axis direction), while the third sub-pixel SP3 may be disposed relative to one or more of the first sub-pixel SP1 or the second sub-pixel SP2 in a first direction different from the second direction (e.g., the X-axis direction). However, the present invention is not limited thereto.

[0032] The first sub-pixel SP1, the second sub-pixel SP2, and the third sub-pixel SP3 can display different colors from each other. Depending on the need, some sub-pixels SP1, SP2, and SP3 can display the same color. Each of the first sub-pixel SP1, the second sub-pixel SP2, and the third sub-pixel SP3 can be one of a red sub-pixel, a green sub-pixel, a blue sub-pixel, or a white sub-pixel. In this invention, the first sub-pixel SP1 is described as a green sub-pixel, the second sub-pixel SP2 as a red sub-pixel, and the third sub-pixel SP3 as a blue sub-pixel. However, the invention is not limited thereto.

[0033] Referring to Figures 1 to 3, a display device 100 according to an exemplary embodiment of the present invention includes: a substrate SUB; a transistor layer TRL; a planarization layer PLN; a light-emitting diode layer EDL; and an encapsulation layer ENCAP.

[0034] The substrate SUB supports various components included in the display device 100 and may be made of an insulating material. The substrate SUB may include: a first substrate 110a; a second substrate 110b; and an interlayer insulating film 110c. For example, the first substrate 110a and the second substrate 110b may be polyimide (PI) substrates. The interlayer insulating film 110c may be disposed between the first substrate 110a and the second substrate 110b. As described above, since the substrate SUB is composed of the first substrate 110a, the second substrate 110b, and the interlayer insulating film 110c, moisture penetration can be suppressed.

[0035] Various patterns 131, 132, 133 and 134 for forming transistors (such as driving transistors Td), various insulating films 111a, 111b, 112, 113a, 113b and 114, and various metal patterns TM, GM and 135 can be disposed in the transistor layer TRL.

[0036] The stacked structure of the transistor layer TRL will be described in more detail below.

[0037] A multiple buffer layer 111a may be disposed on the second substrate 110b. A metal layer 135 may be disposed on the multiple buffer layer 111a. In this document, the metal layer 135 may be used as a light shield and may also be referred to as a light shielding layer.

[0038] An active buffer layer 111b may be disposed on the multiple buffer layer 111a and the metal layer 135. An active layer 134 for driving the transistor Td may be disposed on the active buffer layer 111b. For example, the active layer 134 may be made of polycrystalline silicon (p-Si), amorphous silicon (a-Si), or oxide semiconductor, but is not limited thereto.

[0039] The gate insulating film 112 can be disposed on the active layer 134. The gate insulating film 112 can be composed of a single layer or multiple layers of silicon oxide (SiOx) and silicon nitride (SiNx).

[0040] The gate electrode 131 driving the transistor Td can be disposed on the gate insulating film 112. The gate electrode 131 is disposed on the gate insulating film 112 to overlap with the active layer 134. The gate electrode 131 can be made of various conductive materials (such as magnesium (Mg), aluminum (Al), nickel (Ni), chromium (Cr), molybdenum (Mo), tungsten (W), gold (Au), or alloys thereof). However, the invention is not limited thereto.

[0041] The gate material layer GM can be disposed on the gate insulating film 112 at a position different from the position where the driving transistor Td is located.

[0042] The first interlayer insulating film 113a can be disposed on the gate electrode 131 and the gate material layer GM. The metal pattern TM can be disposed on the first interlayer insulating film 113a. The second interlayer insulating film 113b can be disposed on the first interlayer insulating film 113a to cover the metal pattern TM.

[0043] The source electrode 132 and drain electrode 133 of the driving transistor Td can be disposed on the second interlayer insulating film 113b.

[0044] The source electrode 132 and drain electrode 133 can be connected to one side and the other side of the active layer 134 respectively through contact holes installed in the second interlayer insulating film 113b, the first interlayer insulating film 113a and the gate insulating film 112. The source electrode 132 and drain electrode 133 can be made of various conductive materials such as magnesium (Mg), aluminum (Al), nickel (Ni), chromium (Cr), molybdenum (Mo), tungsten (W), gold (Au) or alloys thereof.

[0045] The portion of the active layer 134 that overlaps with the gate electrode 131 can be used as a channel region. One of the source electrode 132 and the drain electrode 133 is connected to one side of the channel region in the active layer 134, while the other of the source electrode 132 and the drain electrode 133 is connected to the other side of the channel region in the active layer 134.

[0046] The passivation layer 114 can be disposed on the source electrode 132 and the drain electrode 133. The passivation layer 114 is used to protect the driving transistor Td and can be composed of a single layer or multiple layers of inorganic film such as silicon oxide (SiOx) and silicon nitride (SiNx).

[0047] The planarization layer PLN may be located on the transistor layer TRL. The planarization layer PLN may include a first planarization layer 115a and a second planarization layer 115b. The planarization layer PLN is used to protect the driving transistor Td and planarize the upper part of the driving transistor Td. The first planarization layer 115a may be disposed on the passivation layer 114, and the first connection electrode 125 and the second connection electrode 126 may be disposed on the first planarization layer 115a.

[0048] The first connecting electrode 125 can be connected to either the source electrode 132 or the drain electrode 133 through the first contact hole CH1 disposed in the first planarization layer 115a. The second connecting electrode 126 can be exposed through the trench HP disposed in the second planarization layer 115b.

[0049] The second planarization layer 115b may be disposed on the first connecting electrode 125.

[0050] The second planarization layer 115b includes: a second contact hole CH2; and a trench portion HP. The second contact hole CH2 is used to connect the anode 121 of the light-emitting diode 120, described later, to the first connecting electrode 125. For example, a connection portion 127 is formed in the second contact hole CH2, which connects the anode 121 to the first connecting electrode 125. In some embodiments, the connection portion 127 is deposited as the same layer as the anode 121 and is integral with the anode 121, extending within the second contact hole CH2. In some embodiments, the connection portion 127 and the anode 121 are made of different materials or are different layers. The trench portion HP is a region of the second planarization layer 115b. In some embodiments, the anode 121 does not extend into the trench portion HP and is separated from the trench portion HP by a dam 116. Details of the second contact hole CH2 and the trench portion HP will be described below.

[0051] The light-emitting diode layer (EDL) can be located on the second planarization layer 115b.

[0052] The stacked structure of the light-emitting diode (EDL) layer will be described in detail below.

[0053] A light-emitting diode 120 comprising an anode 121, a light-emitting layer 122, and a cathode 123 may be mounted on a second planarization layer 115b.

[0054] The anode 121 may be disposed on the second planarization layer 115B. In this document, the anode 121 may be electrically connected to the first connecting electrode 125 via a second contact hole CH2 disposed in the second planarization layer 115B. The anode 121 may be made of a metallic material.

[0055] The display device 100 may be a top-emitting display device, wherein light emitted from the light-emitting diode 120 is emitted onto the substrate SUB on which the light-emitting diode 120 is disposed. In this case, the anode 121 may further include: a transparent conductive layer; and a reflective layer located on the transparent conductive layer. The transparent conductive layer may be made of a transparent conductive material such as ITO and IZO. The reflective layer may be made of, for example, silver (Ag), aluminum (Al), gold (Au), molybdenum (Mo), tungsten (W), chromium (Cr), or alloys thereof. The anode 121 may be formed separately for each of the first sub-pixel SP1, the second sub-pixel SP2, and the third sub-pixel SP3.

[0056] A dam 116 is disposed on the anode 121 and the second planarization layer 115b. The dam 116 may cover the edge of the anode 121 and border the light-emitting region 140. In this document, the portion of the dam 116 corresponding to the light-emitting region of the sub-pixel may be opened. A portion 121C of the anode 121 may be exposed through the opening of the dam 116. The dam 116 may be made of inorganic insulating materials such as silicon nitride (SiNx) or silicon oxide (SiOx) or organic insulating materials such as benzocyclobutene resin, acrylic resin or amide resin, but is not limited thereto.

[0057] A light-emitting layer 122 may be disposed on and around the opening of the embankment 116. That is, the light-emitting layer 122 may be disposed on the anode 121 exposed through the opening of the embankment 116. The light-emitting layer 122 may comprise a plurality of organic films. The light-emitting layer 122 is a layer in which electrons and holes recombine to emit light. Therefore, light-emitting layers 122 emitting light of corresponding colors may be disposed in sub-pixels SP1, SP2, and SP3 respectively. For example, a green organic light-emitting layer may be disposed in the first sub-pixel SP1, a red organic light-emitting layer may be disposed in the second sub-pixel SP2, and a blue organic light-emitting layer may be disposed in the third sub-pixel SP3. However, the invention is not limited thereto. A single light-emitting layer 122 may be disposed to extend beyond the light-emitting region 140, but when discussing the size or side of the light-emitting layer 122, the portion of the light-emitting layer 122 within the light-emitting region is referred to as the light-emitting layer of the relevant sub-pixel. Similarly, an anode 121 may be disposed to extend beyond, for example, the light-emitting region 140 including portions not exposed by the opening of the embankment 116. When discussing the size or side of anode 121, the portion of anode 121 within the light-emitting area of ​​a sub-pixel is referred to as the anode of the relevant sub-pixel.

[0058] The cathode 123 may be disposed on the light-emitting layer 122. The cathode 123 is not patterned for each of the sub-pixels SP1, SP2, and SP3, but may be mounted as a layer covering the light-emitting layer 122 and the embankment 116. That is, the cathode 123 may be mounted as a single layer in the first sub-pixel SP1, the second sub-pixel SP2, and the third sub-pixel SP3. The cathode 123 may be made of a metallic material with a low work function to smoothly supply electrons to the light-emitting layer 122. For example, the cathode 123 may be made of a metallic material selected from calcium (Ca), barium (Ba), aluminum (Al), silver (Ag), and alloys containing one or more of these, but is not limited thereto. When the display device 100 is configured as a top-emitting type drive, the cathode 123 is formed to have a very small thickness and is substantially transparent.

[0059] To improve the luminous efficacy of the light-emitting diode 120, the light-emitting diode 120 may further include a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer (not shown for simplicity). For example, the hole injection layer and the hole transport layer may be disposed between the anode 121 and the light-emitting layer 122. Additionally, the electron transport layer and the electron injection layer may be disposed between the light-emitting layer 122 and the cathode 123. Furthermore, a hole blocking layer or an electron blocking layer may be provided to further improve the recombination efficiency of holes and electrons in the light-emitting layer 122.

[0060] The encapsulation layer ENCAP can be located on the light-emitting diode layer EDL.

[0061] The encapsulation layer ENCAP can have a single-layer structure or a multi-layer structure. For example, the encapsulation layer ENCAP may include: a first encapsulation layer 117a; a second encapsulation layer 117b; and a third encapsulation layer 117c.

[0062] In this document, the first encapsulation layer 117a and the third encapsulation layer 117c may be inorganic films, while the second encapsulation layer 117b may be an organic film. Among the first encapsulation layer 117a, the second encapsulation layer 117b, and the third encapsulation layer 117c, the second encapsulation layer 117b may be the thickest and may be used as a planarization layer.

[0063] The first encapsulation layer 117a may be disposed on the cathode 123 and closest to the light-emitting diode 120. The first encapsulation layer 117a may be made of an inorganic insulating material suitable for low-temperature deposition. For example, the first encapsulation layer 117a may be made of silicon nitride (SiNx), silicon oxide (SiOx), silicon oxynitride (SiON), or aluminum oxide (Al₂O₃). The first encapsulation layer 117a is deposited in a low-temperature atmosphere. Therefore, the first encapsulation layer 117a can suppress damage to the light-emitting layer 122 containing organic materials susceptible to high-temperature atmospheres during the deposition process.

[0064] The second encapsulation layer 117b may be configured to have a smaller area than the first encapsulation layer 117a. For example, the second encapsulation layer 117b may be configured to expose the end of the first encapsulation layer 117a. For example, the first encapsulation layer 117a may extend laterally beyond the second encapsulation layer 117b. The second encapsulation layer 117b may serve as a buffer layer to reduce interlayer stress caused by bending of the flexible display device, and may also be used to enhance planarization performance.

[0065] For example, the second encapsulation layer 117b may be made of an organic insulating material such as acrylic resin, epoxy resin, polyimide, polyethylene, or silicon oxycarbide (SiOC). For example, the second encapsulation layer 117b may be prepared by inkjet printing, but is not limited thereto.

[0066] The third encapsulation layer 117c may be mounted on the substrate SUB containing the second encapsulation layer 117b to cover the upper and side surfaces of each of the second encapsulation layer 117b and the first encapsulation layer 117a. The third encapsulation layer 117c may reduce or block external moisture or oxygen from penetrating into the first encapsulation layer 117a or the second encapsulation layer 117b. For example, the third encapsulation layer 117c may be made of an inorganic insulating material (such as silicon nitride (SiNx), silicon oxide (SiOx), silicon oxynitride (SiON), or aluminum oxide (Al₂O₃)).

[0067] Although not shown in Figure 3, the color filter can be mounted on the encapsulation layer ENCAP. However, the invention is not limited thereto.

[0068] Although not shown in Figure 3, the touch sensing layer may be further mounted on the encapsulation layer ENCAP. However, the invention is not limited thereto.

[0069] Although not shown in Figure 3, a polarizing layer may be further disposed on the encapsulation layer ENCAP. The polarizing layer disposed in the display area DA of the substrate SUB is used to suppress the reflection of external light. When the display device 100 is used outdoors, external natural light enters and is reflected by the reflective layer contained in the anode 121 of the light-emitting diode 120 or by the metal electrode disposed below the light-emitting diode 120. In this case, the image of the display device 100 may be visually unreadable due to reflected light. The polarizing layer polarizes light entering from the outside in a specific direction and suppresses reflected light from being emitted to the outside of the display device 100.

[0070] Although not shown in Figure 3, the cover glass can be bonded to the polarizing layer using an adhesive layer. The adhesive layer can be used to bond the components of the display device 100 to each other. The adhesive layer can be made of, but is not limited to, optically clear display adhesives such as pressure-sensitive adhesives, optically clear adhesives (OCA), or optically clear resins (OCR). The cover glass can be used to protect the components of the display device 100 from external impacts and to inhibit damage such as scratches.

[0071] The groove portion HP installed in the second planarization layer 115b of the display device 100 according to an exemplary embodiment of the present invention will be described in detail with reference to FIG2 and FIG3.

[0072] The display device 100 has limitations in terms of thickness and brightness, and the upper surface of the planarization layer may not be completely flat for various reasons. For example, contact holes for connecting an anode disposed on the planarization layer to a thin-film transistor are formed in the planarization layer. In this case, the planarization layer surrounding the contact hole may lose height or decrease in height during the process of forming the contact hole. Therefore, when the anode is deposited on the planarization layer after the contact hole is formed, the anode is formed along the shape of the upper surface of the planarization layer. Therefore, the anode surrounding the contact hole may be partially tilted along the upper surface of the planarization layer. Generally, the contact hole is arranged to overlap with the side portion of the anode. Therefore, the side portion of the anode overlapping the contact hole has a different tilt than the other side portion of the anode. Therefore, the anode can be disposed on the planarization layer to have an asymmetrical shape in cross-section. This structure will be described together with the structure of the display device according to the illustrative example.

[0073] Figure 4 is a schematic cross-sectional view of an illustrative example. Referring to Figure 4, in the display device according to the illustrative example, the upper surfaces of the insulating film 13b and the planarization layers 15a and 15b located at the upper part are uneven due to the plurality of metal patterns TM located at the lower part. Therefore, the surface of the anode 21 adjacent to the contact hole is uneven and has an uneven shape S. Furthermore, it can be seen that the side portion of the anode 21 overlapping the contact hole is more inclined downward than the other side portion of the anode 21, and the anode 21 is asymmetrical in the lateral direction. According to the illustrative example shown in Figure 4, it can be seen that the inclination of the left and right sides of the anode 21 differs by approximately 2.0°.

[0074] As described above, if the anode has an asymmetrical shape with different inclinations between one side and the other side, the luminous efficacy of the subpixel may be degraded. For example, if the anode is asymmetrically arranged, the light-emitting diode may also have an asymmetrical uneven surface, which can lead to a degraded viewing angle. For example, when measuring color coordinates while changing the azimuth angle at the same viewing angle, ASCS may occur.

[0075] In the following text, ASCS that occurs when the azimuth angle is changed at the same viewpoint will be described with reference to Figures 5A and 5B.

[0076] Figures 5A and 5B are diagrams illustrating the spherical coordinate system on the display device.

[0077] As shown in Figures 5A and 5B, a spherical coordinate system can be referenced on the display device 100. The origin of the spherical coordinate system can be located at the center of the display area DA of the display device 100. The spherical coordinate system is used to distinguish measurement points for determining the display quality of the display device 100.

[0078] The coordinates of a spherical coordinate system can be represented by r, θ, and Φ. In this paper, r is the distance from the origin to the measurement point, θ is the angle between the Z-axis (or the normal axis of the display device 100) and the straight line along the origin and the measurement point, and Φ is the angle between the Y-axis (or the horizontal axis passing through the center of the display device 100) and the straight line projected onto the XY plane (or the front surface of the display device 100) along the straight line along the origin and the measurement point. For ease of description, θ is called the viewing angle, and Φ is called the azimuth angle.

[0079] Figure 5A shows five measurement points P1 to P5. The first viewing angle of the first measurement point P1 is 0°. Each of the second to fifth viewing angles θ1, θ2, θ3, and θ4 of the second to fifth measurement points P2 to P5 has a certain angle with the Z-axis (or the normal axis of the display device 100). The second to fifth viewing angles θ1, θ2, θ3, and θ4 of the second to fifth measurement points P2 to P5 can be 15°, 30°, 45°, and 60°, respectively. The second to fifth viewing angles θ1, θ2, θ3, and θ4 of the second to fifth measurement points P2 to P5 can be 20°, 40°, 60°, and 80°, respectively. The second to fifth viewing angles θ1, θ2, θ3, and θ4 of the second to fifth measurement points P2 to P5 can also be 10°, 20°, 30°, and 40°, respectively.

[0080] Figure 5B shows eight azimuth angles Φ1 to Φ8 as examples. The first to eighth azimuth angles can be 0°, 45°, 90°, 135°, 180°, 225°, 270° and 315° respectively.

[0081] The ASCS that occurs when the azimuth angle changes at the same viewing angle can be measured as the changes in color coordinates Δu' and Δv' in the Z-axis direction when the azimuth angle Φ1 to Φ8 is changed at a certain viewing angle θ1, θ2, θ3, or θ4. The changes in color coordinates Δu' and Δv' can be based on the color coordinates u' and v' of the CIE 1976 color coordinate system.

[0082] A display device 100 according to an exemplary embodiment of the present invention includes a trench portion HP corresponding to a second contact hole CH2 disposed in a second planarization layer 115b. A trench portion HP corresponding to each sub-pixel can be provided. For example, the trench portion HP can be provided in each of the first sub-pixel SP1, the second sub-pixel SP2, and the third sub-pixel SP3. For example, the first trench portion HP1 can be provided in the first sub-pixel SP1, the second trench portion HP2 can be provided in the second sub-pixel SP2, and the third trench portion HP3 can be provided in the third sub-pixel SP3. The first trench portion HP1, the second trench portion HP2, and the third trench portion HP3 can differ from each other in shape, size, depth, position, etc. The shape of the first trench portion HP1, the second trench portion HP2, and the third trench portion HP3 can vary according to the shape of the second contact holes CH2a, CH2b, and CH2c disposed in their respective sub-pixels.

[0083] For example, the trench portion HP may be located opposite the second contact hole CH2, based on or relative to the anode 121 and / or across the center line 122(cl) (122a(cl), 122b(cl), 122c(cl) shown in FIG. 2) of the light-emitting region 140 between the trench portion HP and the corresponding second contact hole CH2. For example, referring to FIG. 2, the trench portion HP1 of the first sub-pixel SP1 is located opposite the second contact hole CH2a in the second planarization layer 115b of the first sub-pixel SP1, across the center line 122a(cl) of the light-emitting region 140a in the Y-axis direction. For example, the trench portion HP1 is substantially symmetrical in position to the second contact hole CH2a along the X-axis relative to the center line 122a(cl). FIG. 2 shows the trench portion HP1 being symmetrical in position to the second contact hole CH2a along the X-axis based on the center line 122a(cl). However, the present invention is not limited thereto. The centerline of the light-emitting region can be any line passing through the center of the light-emitting region, and the trench portion HP can be symmetrical in position to the second contact hole CH2 based on any of these centerlines passing through the center of the light-emitting region 140. Alternatively or additionally, the trench portion HP can be symmetrical to the second contact hole CH2 based on the centerline passing through the center of the respective anode 121 or the center of the respective light-emitting layer 122. For example, the trench portion HP2 of the second sub-pixel SP2 can be located opposite the second contact hole CH2b of the second sub-pixel SP2 in the Y-axis direction, for example, the two are symmetrical based on centerline 122b(cl). Furthermore, the trench portion HP3 of the third sub-pixel SP3 can be located opposite the second contact hole CH2c of the third sub-pixel SP3 in the X-axis direction, for example, the two are symmetrical based on centerline 122c(cl).

[0084] Figure 2 shows that the first sub-pixel SP1, the second sub-pixel SP2, and the third sub-pixel SP3 all include trench portions HP (HP1, HP2, and HP3). However, the present invention is not limited thereto. For example, in some embodiments, some, but not all, sub-pixels include trench portions HP. For example, in some embodiments, only the second sub-pixel SP2, which is a red sub-pixel, includes a second trench portion HP2. In this case, the first sub-pixel SP1, which is a green sub-pixel, and the third sub-pixel SP3, which is a blue sub-pixel, may not include the first trench portion HP1 and the third trench portion HP3, respectively. Referring to Figure 2, the second contact hole CH2b of the second sub-pixel SP2 can be installed in the narrow space between the first sub-pixel SP1 and the second sub-pixel SP2. In this case, it is difficult to install additional components for planarizing the second planarization layer 115b and the anode 121. Therefore, in the second sub-pixel SP2, the trench portion HP2 can be provided in a wide space opposite to the second contact hole CH2.

[0085] Referring to Figure 3, the groove portion HP is located opposite the second contact hole CH2 in, for example, the Y-axis direction. The groove portion HP may have a width W2 and a depth D2 that are substantially the same as the width W1 and depth D1 of the second contact hole CH2. Since the groove portion HP is mounted relative to the second contact hole CH2, the upper surfaces of the second planarization layer 115b adjacent to the second contact hole CH2 and the groove portion HP decrease in height with the same inclination. That is, the two portions of the second planarization layer 115b adjacent to the second contact hole CH2 and the groove portion HP are substantially symmetrical to each other in shape or form. Furthermore, the anode 121 and the light-emitting layer 122 are disposed on the second planarization layer 115b. Therefore, the side portion of the anode 121 or the light-emitting layer 122 adjacent to the second contact hole CH2 and the other side portion of the anode 121 or the light-emitting layer 122 adjacent to the groove portion HP decrease in height along the upper surface of the second planarization layer 115b with the same inclination. That is, the side portion of the anode 121 or the light-emitting layer 122 adjacent to the second contact hole CH2 and the other side portion of the anode 121 or the light-emitting layer 122 adjacent to the trench portion HP are symmetrical about each other in the Y-axis direction.

[0086] In this case, the ASCS that occurs when the azimuth angle is changed in the Z-axis direction at the same viewing angle can be significantly reduced. For example, in the second sub-pixel SP2, the second contact hole CH2 and the trench HP are symmetrical about each other in the Y-axis direction based on the anode 121. Therefore, the ASCS of the second sub-pixel SP2 measured in the Z-axis direction at the same viewing angle at azimuth angles of 90° and 270° can be reduced.

[0087] Meanwhile, the groove portion HP can have substantially the same shape as the second contact hole CH2. However, the invention is not limited thereto. For example, the depth D2 of the groove portion HP can be 90% to 110% or 94% to 105% of the depth D1 of the second contact hole CH2. Furthermore, the width W2 of the groove portion HP in cross-section can be 75% to 125% of the width W1 of the second contact hole CH2. When the depth and size of the groove portion HP satisfy the above-mentioned range (referred to as the similarity range or threshold range) based on the second contact hole CH2, the difference in inclination between the anode adjacent to the groove portion HP and the anode adjacent to the second contact hole CH2 can be reduced to less than 2° or 1°. Therefore, the ASCS that occurs when changing the azimuth angle in the Z-axis direction at the same viewing angle can be reduced.

[0088] The distance d2 (d2a, d2b, d2c shown in FIG. 2) from the side portion of the light-emitting region 140 or the side portion of the anode 121 in the light-emitting region 140 to the trench portion HP can be within a similarity range of 80% to 120% to the distance d1 (d1a, d1b, d1c shown in FIG. 2) from the other side portion of the light-emitting region 140 or the other side portion of the anode 121 in the light-emitting region 140 to the second contact hole CH2. In other words, the difference between distance d2 and distance d1 is within a threshold range, for example, 0% to 20% of d1. When the distance d2 from the side portion of the light-emitting region 140 or the side portion of the anode 121 to the trench portion HP satisfies the above range based on the second contact hole CH2, the flatness of the anode 121 can be improved considering the process margin, and thus the light-emitting layer 122 can be improved. The distance d2 from the side portion of the light-emitting region 140 or the side portion of the anode 121 in the light-emitting region 140 to the trench portion HP can vary depending on the sub-pixel array structure and the type of sub-pixel. For example, referring to FIG2, the distance d2a from the side portion of the light-emitting region 140a or the side portion of the anode 121a of the first sub-pixel SP1 (which is, for example, a green sub-pixel) to the trench portion HP1 can be 86% to 114% of the distance d1a from the other side portion of the light-emitting region 140a or the other side portion of the anode 121a to the second contact hole CH2a. Furthermore, the distance d2b from the side portion of the light-emitting region 140b or the side portion of the anode 121b of the second sub-pixel SP2 (which is a red sub-pixel) to the trench portion HP2 can be 86% to 114% of the distance d1b from the other side portion of the light-emitting region 140b or the other side portion of the anode 121b to the second contact hole CH2b. Furthermore, the distance d2c from the side portion of the light-emitting region 140c or the side portion of the anode 121c of the third sub-pixel SP3 (which is a blue sub-pixel) to the trench HP3 can be 83% to 117% of the distance d1c from the other side portion of the light-emitting region 140c or the other side portion of the anode 121c to the second contact hole CH2c. When the distance from the side portion of the light-emitting region 140 or the side portion of the anode 121 in the light-emitting region 140 to the trench HP satisfies the above range, the difference in tilt between the anode adjacent to the trench HP and the anode adjacent to the second contact hole CH2 can be reduced. In addition, considering the distance between sub-pixels, the reduction in the tilt of the anode adjacent to the trench HP can be suppressed.

[0089] Figure 6 is a plan view of a display device according to an exemplary embodiment of the present invention. Figure 7 is a cross-sectional view taken along line II-II' of Figure 6.

[0090] Except that the display device 200 further includes a dummy electrode 227 but does not include a second connection electrode, the display device 200 shown in Figures 6 and 7 is substantially the same as the display device 100 shown in Figures 2 and 3. Therefore, its lengthy description is omitted.

[0091] Referring to Figures 6 and 7, a virtual electrode 227 is disposed in a trench portion HP formed in the second planarization layer 115b. The virtual electrode 227 may be made of the same material as the anode 121 on the same layer. The virtual electrode 227 causes a portion of the anode 121 to be recessed along the shape of the corresponding portion of the anode 121 that is inclined by the second contact hole CH2. Therefore, the anode 121 has a symmetrical shape.

[0092] For example, referring to Figures 6 and 7, the virtual electrode 227 is disposed in the trench portion HP, spaced apart from the anode 121, and thus has an island shape. The virtual electrode 227 and the trench portion HP correspond to the second contact hole CH2 and the anode 121 disposed in the second contact hole CH2. Therefore, when the second contact hole CH2 tilts one side of the anode 121, the other side of the anode 121 can also tilt accordingly. Thus, this side of the anode 121 and the other side of the anode 121 can be symmetrical to each other. In this document, the second connecting electrode is not disposed below the virtual electrode 227. However, the invention is not limited thereto.

[0093] Figure 8 is a cross-sectional view of a display device according to an exemplary embodiment of the present invention.

[0094] Except that the display device 300 further includes a second connection electrode 326 and the virtual electrode 227 contacts the second connection electrode 326, the display device 300 shown in FIG8 is substantially the same as the display device 200 shown in FIG6 and FIG7. Therefore, its lengthy description is omitted.

[0095] In the display device 300 shown in FIG8, a second connection electrode 326 is disposed on the first planarization layer 115a, corresponding to the trench portion HP. Since the trench portion HP exposes the second connection electrode 326, the dummy electrode 227 directly contacts the second connection electrode 326 through the trench portion HP. The second connection electrode 326 can be connected to a power supply line. In this case, the resistance can be reduced by the dummy electrode 227. Therefore, the voltage drop (IR drop) can be improved.

[0096] Figure 9 is a plan view of a display device according to an exemplary embodiment of the present invention.

[0097] Except that the display device 400 further includes a fourth sub-pixel SP4 and a trench portion HP4 and a virtual electrode 227d in the fourth sub-pixel SP4, the display device 400 shown in FIG9 is substantially the same as the display device 100 shown in FIG2. Therefore, its lengthy description is omitted.

[0098] Referring to Figure 9, a pixel PX may further include a fourth sub-pixel SP4. The fourth sub-pixel SP4 may display the same color or a different color as one of the first sub-pixel SP1, the second sub-pixel SP2, and the third sub-pixel SP3. For example, the sub-pixels may be configured to have a pentile structure, where the first sub-pixel SP1 and the third sub-pixel SP3 are red and blue sub-pixels, respectively, while the second sub-pixel SP2 and the fourth sub-pixel SP4 are both green sub-pixels.

[0099] In this configuration, each of the first sub-pixel SP1, the second sub-pixel SP2, the third sub-pixel SP3, and the fourth sub-pixel SP4 may include a trench portion HP and a dummy electrode 227. In this document, the trench portion HP and the dummy electrode 227 may be disposed opposite to the second contact hole CH2 formed in the second planarization layer 115b. For example, referring to FIG9, the trench portion HP1 and the dummy electrode 227a in the first sub-pixel SP1 may be disposed in the X-axis direction at a position symmetrical to the second contact hole CH2a. Therefore, the anode 121a may have a symmetrical tilt. Similarly, the trench portions HP2, HP4 and the dummy electrodes 227b, 227d in each of the second sub-pixels SP2 and the fourth sub-pixel SP4 may be disposed in the diagonal direction in the XY plane at a position symmetrical to the second contact holes CH2b, CH2d. Furthermore, the trench portion HP3 and the dummy electrode 227c in the third sub-pixel SP3 may be disposed in the diagonal direction in the XY plane at a position symmetrical to the second contact hole CH2c.

[0100] In this invention, the display device 100 has been described as a top-emitting display device. However, the invention is not limited thereto. The display device 100 can also be implemented as a bottom-emitting display device. In the bottom-emitting display device 100, the anode 121 can be made of only a transparent conductive material without a reflective layer. However, even in the bottom-emitting display device 100, the trench portion HP and the virtual electrode 227 can be mounted on a planarization layer, thereby giving the anode 121, whose side portion is recessed due to the contact hole, a symmetrical structure.

[0101] In the following description, the effects of forming the groove portion will be described in more detail with reference to embodiments and illustrative examples of the present invention. However, the following embodiments are used to illustrate the present invention, and the scope of the present invention is not limited to the following embodiments. The structure of the illustrative example will be described with reference to FIG10. FIG10 shows schematic cross-sectional views of the light-emitting diodes of the display devices according to illustrative example 1 and illustrative example 2, respectively.

[0102] Referring to Figure 10, as a cross-section of the red sub-pixel, illustrative example 1 has a structure in which the anode is connected to the first connecting electrode through a second contact hole. In this document, the second contact hole is spaced 1.4 μm from the side portion of the anode 21. Referring to Figure 10, the side portion of the anode 21 is recessed due to the second contact hole. In illustrative example 1, the difference in inclination between one side portion and the other side portion of the anode 21 adjacent to the second contact hole is 2.1°.

[0103] Compared to illustrative example 1, illustrative example 2, as a cross-section of the red sub-pixel, has a structure in which the embankment 16 extends toward the light-emitting region. That is, the end of the embankment 16 in illustrative example 1 is aligned with L1, while the end of the embankment 16 in illustrative example 2 is aligned with L2. Therefore, the second contact hole is spaced 2.4 μm apart from the side portion of the anode 21. In illustrative example 2, the embankment 16 extends toward the light-emitting region. Therefore, the recessed portion of the anode 21 can be covered by the second contact hole, and thus, the anode 21 can have a flat shape in the portion opened by the embankment 16. In illustrative example 2, the difference in inclination between one side portion and the other side portion of the anode 21 adjacent to the second contact hole is 1.6°.

[0104] In an embodiment of the present invention, the trench portion HP and the second contact hole CH2 of the red sub-pixel are mounted opposite each other, as shown in Figures 2 and 3. In this paper, the second contact hole CH2 is spaced 1.4 μm apart from the side portion of the anode 121, and the trench portion HP is spaced 1.4 μm apart from the other side portion of the anode 121.

[0105] In the following description, ASCS occurring when the azimuth angle is changed at the same viewing angle is measured in each of Illustrative Example 1, Illustrative Example 2, and Embodiment 1 of the present invention.

[0106] Figure 11 is a graph showing the ASCS (Autonomous Aspect Ratio) measured in each of Illustrative Example 1, Illustrative Example 2, and Embodiment 1 of the present invention, depending on the viewing angle and azimuth angle. Figure 11 shows the ASCS values ​​(Δu'v') between the azimuth angle Φ of 90° and 270° as the viewing angle θ on the Z-axis changes.

[0107] Referring to Figure 11, it can be seen that in illustrative example 2, the ASCS is reduced compared to illustrative example 1, but the effect is not significant. However, it can be seen that in embodiment 1 of the present invention, the ASCS is reduced by approximately 40% compared to illustrative example 1. Furthermore, in illustrative example 2, the embankment extends to cover the non-flat portion of the anode, and therefore the size of the light-emitting region of the sub-pixel is reduced, which leads to a shortened lifetime of the light-emitting diode. However, in embodiment 1 of the present invention, the size of the flat portion of the anode is increased, and the anode has a symmetrical shape, without any reduction in the size of the light-emitting region. Therefore, the size of the light-emitting region can also be increased. Therefore, in embodiment 1 of the present invention, the lifetime can be improved compared to illustrative example 2.

[0108] Exemplary embodiments of the present invention may also be described below.

[0109] According to one aspect of the present invention, a display device is provided. The display device includes: a substrate comprising a plurality of sub-pixels; a thin-film transistor disposed on the substrate; a planarization layer disposed on the thin-film transistor; an anode disposed on the planarization layer and for each sub-pixel; a light-emitting layer disposed on the anode; and a cathode disposed on the light-emitting layer. The planarization layer includes: a contact hole for connecting the anode and the thin-film transistor; and a trench portion located opposite the contact hole based on the anode.

[0110] The groove section can be configured to be symmetrical about the anode and the contact hole.

[0111] The contact hole can be spaced apart from the side of the anode by a predetermined distance, and the groove portion can be spaced apart from the other side of the anode by the same predetermined distance.

[0112] The distance from the other side of the anode to the groove can be 80% to 120% of the distance from the side of the anode to the contact hole.

[0113] The anode can be symmetrical in the transverse direction based on the cross-section of the side portion of the anode and another side portion.

[0114] The planarization layer may include: a first planarization layer located on a thin-film transistor; and a second planarization layer located on the first planarization layer. The contact hole may include: a first contact hole disposed in the first planarization layer; and a second contact hole disposed in the second planarization layer, and the trench portion may have the same depth as the second contact hole.

[0115] The display device may further include a first connection electrode and a second connection electrode located on a first planarization layer. A second contact hole may expose the first connection electrode and connect the first connection electrode to the anode. A trench may overlap with the second connection electrode and expose the second connection electrode.

[0116] The display device may further include a virtual electrode disposed in the trench portion. The virtual electrode may be mounted on the same layer as the anode.

[0117] The virtual electrode can be spaced a predetermined distance from the anode.

[0118] The display device may further include a first connection electrode and a second connection electrode located on a first planarization layer. The anode may contact the first connection electrode through a second contact hole, while the virtual electrode may contact the second connection electrode through a trench.

[0119] Although exemplary embodiments of the invention have been described in detail with reference to the accompanying drawings, the invention is not limited thereto and may be embodied in many different forms without departing from the technical concept of the invention. Therefore, the exemplary embodiments of the invention are provided for illustrative purposes only and are not intended to limit the technical concept of the invention. The scope of the technical concept of the invention is not limited thereto. Therefore, it should be understood that the exemplary embodiments described above are illustrative in nature and do not limit the invention. The scope of protection of the invention should be interpreted based on the following claims scope, and all technical concepts within its equivalent scope should be interpreted as falling within the scope of the invention.

[0120] The various embodiments described above can be combined to provide further embodiments. The nature of the embodiments can be modified as needed to provide even further embodiments using the concepts of various embodiments.

[0121] Based on the detailed description above, such and other changes can be made to the embodiments. Generally, the terminology used in the following claims should not be construed as limiting the scope of the claims to the specific embodiments disclosed in the specification and claims, but should be construed as encompassing the entire range of all possible embodiments together with the entitled equivalents claimed in this claim. Therefore, the scope of the claims is not limited to this invention.

[0122] This application claims priority to Korean Patent Application No. 10-2024-0030305, filed on February 29, 2024, with the Korean Intellectual Property Office, the invention of which is incorporated herein by reference.

[0123] 13b: Insulating film 15a, 15b: Planarization layers 16: Embankment 21: Anode 100: Display device 110a: First substrate 110b: Second substrate 110c: Interlayer insulating film 111a: Insulating film, multiple buffer layers 111b: Insulating film, active buffer layer 112: Insulating film, gate insulating film 113a: Insulating film, first interlayer insulating film 113b: Insulating film, second interlayer insulating film 114: Insulating film, passivation layer 115a: First planarization layer 115b: Second planarization layer 116: Embankment 117a: First encapsulation layer 117b: Second encapsulation layer 117c: Third encapsulation layer 120: Light Emitting Diode 121, 121a, 121b, 121c: Anode 122: Emissive Layer 122(cl): Centerline 123: Cathode 122a(cl), 122b(cl), 122c(cl): Centerline 125: First connecting electrode 126: Second connecting electrode 127: Connection part 131: Pattern, Gate Electrode 132: Pattern, Source Electrode 133: Pattern, Drain Electrode 134: Pattern, Active Layer 135: Metallic patterns, metallic layers 140, 140a, 140b, 140c: Emitting regions 200: Display device 227, 227a, 227b, 227c, 227d: Virtual electrodes 300: Display device 326: Second connecting electrode 400: Display device CH1: First contact hole CH2, CH2a, CH2b, CH2c, CH2d: Second contact hole D1, D2: Depth d1, d1a, d1b, d1c, d2, d2a, d2b, d2c: Distance DA: Display area EDL: Light Emitting Diode Layer ENCAP: Encapsulation layer GM: Metal pattern, gate material layer HP, HP1, HP2, HP3, HP4: Grooves NDA: Non-display area P1, P2, P3, P4, P5: Measurement points PLN: Planarization layer PX: pixel S: Uneven shape SP1: Subpixel, First Subpixel SP2: Sub-pixel, Second Sub-pixel SP3: Subpixel, Third Subpixel SP4: Fourth subpixel SUB:Substrate Td: Driving transistor TM: Metal Pattern TRL: Transistor Layer W1, W2: Width X: X-axis Y: Y-axis Z: Z-axis θ1, θ2, θ3, θ4: Viewpoint Φ, Φ1, Φ2, Φ3, Φ4, Φ5, Φ6, Φ7, Φ8: azimuth angle

Claims

1. A display device, comprising: A substrate comprising a plurality of sub-pixels; a thin-film transistor located on the substrate; A planarization layer is located on the thin-film transistor; an anode is disposed on the planarization layer and for each sub-pixel; a light-emitting layer is disposed on the anode; and a cathode is located on the light-emitting layer, wherein the planarization layer includes: a contact hole for connecting the anode and the thin-film transistor; and a trench portion based on the anode being located opposite the contact hole, and wherein the trench portion is configured to be substantially symmetrical based on the anode and the contact hole.

2. The display device as described in claim 1, wherein, The contact hole is spaced apart from a first side surface of the anode by a first distance, the groove is spaced apart from a second side surface of the anode by a second distance, the second side surface is opposite to the first side surface, and the second distance is within a threshold range of a percentage of the first distance.

3. The display device as described in claim 2, wherein, The second distance from the second side surface of the anode to the trench is 80% to 120% of the first distance from the first side surface of the anode to the contact hole.

4. The display device as described in claim 2, wherein, The anode is symmetrical in the transverse direction based on the cross-section between the first side portion and the second side portion of the anode.

5. The display device as described in claim 1, wherein, The planarization layer includes: a first planarization layer located on the thin-film transistor; and a second planarization layer located on the first planarization layer. The contact hole includes: a first contact hole located in the first planarization layer; and a second contact hole located in the second planarization layer. The trench portion and the second contact hole have substantially the same depth.

6. The display device as described in claim 5, further comprising: A connecting portion is located in the second contact hole; A first connecting electrode and a second connecting electrode are located on the first planarization layer, wherein the second contact hole exposes at least a portion of the first connecting electrode, the connecting portion connects the first connecting electrode to the anode, and the trench portion overlaps with the second connecting electrode and exposes at least a portion of the second connecting electrode.

7. The display device as described in claim 5, further comprising: A virtual electrode is disposed in the trench portion, wherein the virtual electrode and the anode are mounted on the same layer.

8. The display device as described in claim 7, wherein, The virtual electrode is spaced apart from the anode.

9. The display device as described in claim 7, further comprising: A first connecting electrode and a second connecting electrode are located on the first planarization layer, wherein the anode contacts the first connecting electrode through the second contact hole, and the virtual electrode contacts the second connecting electrode through the trench portion.

10. A display device, comprising: A substrate comprising a plurality of sub-pixels; a thin-film transistor located on the substrate; A planarization layer is located on the thin-film transistor; an anode is located on the planarization layer; a dam is located on the anode and has a light-emitting region exposing a portion of the anode; a light-emitting layer is disposed on the anode surrounding the light-emitting region; and a cathode is located on the light-emitting layer, wherein the planarization layer includes: a first hole adjacent to a first side portion of the light-emitting region; and a second hole adjacent to a second side portion of the light-emitting region, the second side portion being opposite to the first side portion of the light-emitting region, and wherein the first hole and the second hole are substantially symmetrical to each other in position relative to a centerline passing through the light-emitting region.

11. The display device as claimed in claim 10, further comprising a connection pattern located in the first hole, the connection pattern being connected to the anode, wherein, The anode is separated from the second hole through the embankment.

12. The display device as claimed in claim 11 further includes a virtual electrode located in the second hole, the virtual electrode being separated from the anode by a distance.

13. The display device as claimed in claim 10, wherein, One layer of the anode extends into the first hole, and the anode layer does not extend into the second hole.

14. The display device as claimed in claim 10, wherein, The first hole has a first width, and the second hole has a second width, which is 75% to 125% of the first width.

15. The display device as claimed in claim 10, wherein, The first hole has a first depth, and the second hole has a second depth, which is 90% to 110% of the first depth.

16. The display device as claimed in claim 10, wherein, The anode is connected to the thin-film transistor through the first hole and separated from the second hole through the dam.

17. A display device, comprising: One substrate; A thin-film transistor is located on the substrate; A planarization layer is located on the thin-film transistor; an anode is located on the planarization layer; a dam is located on the anode and has an opening exposing a first portion of the anode; wherein the planarization layer includes a first hole and a second hole; and wherein the first portion of the anode is located between the first hole and the second hole, and wherein the first hole is substantially symmetrical with respect to the first portion of the anode and the second hole.

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