Display device

Abstract

Provided is a display device including: an optical layer disposed on a display unit and including a cholesteric liquid crystal; and a cover glass disposed on the optical layer, in which the cover glass includes a flat portion and a curved portion disposed outside the flat portion, and the cholesteric liquid crystal overlaps the curved portion. According to the present invention, by forming an optical layer between a display unit and a cover glass, a viewing angle-based color change of a flat portion and a curved portion of the cover glass can be minimized.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10 - 2023 - 0190060, filed on December 22, 2023, which is incorporated herein by reference in its entirety as if fully set forth herein. Technical field

[0003] The present invention relates to a display device. Background art

[0004] Display devices are widely used as display screens for laptops, tablets, smartphones, portable display devices, and portable information devices, as well as for televisions or monitors. With the development of technology, in addition to the image display function, display devices can also provide a photographing function or various sensing functions. Therefore, display devices need to include electronic devices such as cameras or sensors.

[0005] Among display devices, an organic light - emitting display device is a self - emissive type, having advantages such as excellent viewing angles and contrast ratios compared to liquid crystal displays (LCDs), and because it does not require a separate backlight, it is possible to have a light weight and a thin thickness, and the power consumption is favorable. In addition, the organic light - emitting display device has the advantages of being able to drive at a DC low voltage, having a fast response speed, and especially a low manufacturing cost.

[0006] Recently, in order to minimize the bezel area of a display device, cover glass having a curvature in the edge region has been used. However, due to this curvature, the brightness and the light wavelength band vary according to the viewing angle, and research is being conducted to solve this problem. Summary of the invention

[0007] The present invention has been made in view of the above problems, and an object of the present invention is to provide a display device with improved viewing angle characteristics for a curved surface.

[0008] According to one aspect of the present invention, the above object and other objects can be achieved by providing a display device including: a display unit including a display area provided with a plurality of sub - pixels and a non - display area surrounding the display area; an optical layer disposed on the display unit and including a cholesteric liquid crystal; and a cover glass disposed on the optical layer, wherein the cover glass includes a flat portion and a curved portion disposed outside the flat portion, and the cholesteric liquid crystal overlaps with the curved portion.

[0009] In addition, according to an aspect of the present invention, the above object and other objects can be achieved by providing a display device, the display device including: a substrate including a display area provided with a plurality of sub-pixels and a non-display area surrounding the display area; a light-emitting device provided on the substrate and in each of the plurality of sub-pixels; a packaging layer provided in the display area and the non-display area and covering the light-emitting device; an optical layer provided on the packaging layer, the optical layer including a first area and a second area having characteristics different from those of the first area; and a cover glass provided on the optical layer, the cover glass including a flat portion and a curved portion, wherein the entire first area of the optical layer corresponds to the display area, and the second area of the optical layer includes a first portion corresponding to the display area and a second portion corresponding to the non-display area. Description of the Drawings

[0010] Figure 1 is an exploded perspective view of a display device according to an embodiment of the present invention.

[0011] Figure 2 and Figure 3 is a plan view of a display device according to an embodiment of the present invention.

[0012] Figure 4 is a cross-sectional view of a sub-pixel SP according to an embodiment of the present invention.

[0013] Figure 5 (a) to (c) of are wavelength and luminance curves of sub-pixels in a first group of regions according to an embodiment of the present invention based on the viewing angle.

[0014] Figure 6 (a) to (f) of are luminance curves of sub-pixels in a first group of regions and a second group of regions according to an embodiment of the present invention.

[0015] Figure 7 is a cross-sectional view of a display device according to an embodiment of the present invention.

[0016] Figure 8 (a) to (d) of are curves showing color changes of sub-pixels in a first group of regions and a second group of regions based on the viewing angle according to an embodiment of the present invention.

[0017] Figure 9 is a cross-sectional view of a display device according to another embodiment of the present invention. Detailed Description of the Embodiments

[0018] The advantages, features, and methods for implementing the present invention will be clarified by the following embodiments described with reference to the accompanying drawings. However, the present invention can be implemented in different forms and should not be construed as limited to the embodiments listed herein. Instead, these embodiments are provided to make the present disclosure comprehensive and complete, and to fully convey the scope of the present invention to those skilled in the art. In addition, the present invention is only defined by the scope of the claims.

[0019] The shapes, sizes, proportions, angles, and quantities disclosed in the accompanying drawings for describing the embodiments of the present invention are only examples, and thus the present invention is not limited to the details illustrated. The same reference numerals refer to the same elements throughout. In the following description, when it is determined that a detailed description of related known functions or configurations will unnecessarily obscure the key points of the present invention, such detailed description will be omitted. When using "comprising", "having", and "including" to describe in the present invention, other parts may be added unless "only" is used. Terms in the singular form may include the plural form unless there is a contrary indication.

[0020] When interpreting an element, although not explicitly described, the element is interpreted as including an error range.

[0021] When describing positional relationships, for example, when the positional relationship is described as "on...", "above...", "below...", and "after...", one or more other parts may be provided between the two parts unless "exactly" or "directly" is used.

[0022] It will be understood that although terms such as "first" and "second" may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of the present invention, the first element may be referred to as the second element, and similarly, the second element may be referred to as the first element.

[0023] Those skilled in the art can fully understand that the features of the embodiments of the present invention can be partially or wholly combined or combined with each other, and various interoperations and drives can be performed technically between them. The embodiments of the present invention can be implemented independently of each other, or can be implemented together in a mutually dependent relationship.

[0024] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0025] Figure 1 is an exploded perspective view of a display device 1000 according to an embodiment of the present invention.

[0026] Referring to Figure 1 , the display device 1000 according to an embodiment of the present invention may include a display unit 10, an optical layer 200, and a cover glass 300.

[0027] The display unit 10 can emit light to display an image. The display unit 10 may include a display area DA and a non-display area NDA surrounding the display area DA. The display area DA is an area where an image can be displayed, and the non-display area NDA is an area where no image is displayed.

[0028] A plurality of sub-pixels SP and a plurality of signal lines for driving the plurality of sub-pixels SP may be provided in the display area DA. The plurality of signal lines may include a plurality of data lines and a plurality of gate lines.

[0029] The optical layer 200 may be provided on the display unit 10. The optical layer 200 may cover the upper surface of the display unit 10. In addition, the optical layer 200 may absorb or reflect the light emitted from the display unit 10. A detailed description thereof will be given later.

[0030] The cover glass 300 may be provided on the optical layer 200. Since the cover glass 300 is configured to transmit the light emitted from the display unit 10, the cover glass 300 may be formed of a transparent material. Although Figure 1 it is illustrated that the area of the lower surface of the cover glass 300 is the same as the area of the upper surface of the optical layer 200, the present invention is not limited thereto. For example, the area of the lower surface of the cover glass 300 may be larger than the area of the upper surface of the optical layer 200. Accordingly, a part of the lower surface of the cover glass 300 may be exposed to the outside. Alternatively, the cover glass 300 may cover a part of the side surface of the optical layer 200 or the display unit 10, but is not limited thereto.

[0031] The cover glass 300 may include a flat portion 310 and a curved portion 320 surrounding the flat portion 310. The upper and lower surfaces of the flat portion 310 may be flat. In addition, the upper surface of the curved portion 320 may have a curvature, and the lower surface of the curved portion 320 may be flat. That is, the thickness of the curved portion 320 may decrease in a direction away from the flat portion 310 starting from the boundary region between the flat portion 310 and the curved portion 320. That is, the thickness of the curved portion 320 may decrease toward the end of the cover glass 300. Accordingly, the edge of the upper surface of the cover glass 300 may be a curved surface.

[0032] In addition, although Figure 1 it is illustrated that the curved portion 320 surrounds the entire edge of the flat portion 310, the present invention is not limited thereto. For example, the curved portion 320 may be provided only in the outer regions of one side and the other side of the flat portion 310 that are not adjacent to each other.

[0033] Figure 2 and Figure 3 are plan views of a display device 1000 according to an embodiment of the present invention. Figure 2 illustrates the display unit 10, Figure 3 illustrates in Figure 2The structure in which the cover glass 300 is provided on the display unit 10.

[0034] Referring to Figure 2 , the display unit 10 may include a display area DA and a non-display area NDA surrounding the display area DA. A plurality of sub-pixels SP may be provided in the display area DA. The plurality of sub-pixels SP may be arranged in a matrix form having a plurality of rows and columns.

[0035] The plurality of sub-pixels SP may include a plurality of red sub-pixels SP_R, a plurality of green sub-pixels SP_G, and a plurality of blue sub-pixels SP_B. The red sub-pixel SP_R may emit red light, the green sub-pixel SP_G may emit green light, and the blue sub-pixel SP_B may emit blue light. Although Figure 2 illustrates a structure in which the red sub-pixel SP_R, the green sub-pixel SP_G, and the blue sub-pixel SP_B are arranged in sequence in the horizontal direction, it is not limited thereto. In addition, the plurality of sub-pixels SP may further include white sub-pixels that emit white light, but it is not limited thereto.

[0036] In this case, the plurality of sub-pixels SP may be composed of a plurality of unit pixels UP including one red sub-pixel SP_R, one green sub-pixel SP_G, and one blue sub-pixel SP_B formed in sequence.

[0037] Referring to Figure 3 , the cover glass 300 may cover the upper surface of the display unit 10. As described above, the cover glass 300 may include a flat portion 310 having a flat upper surface, and a curved portion 320 surrounding the flat portion 310 and having a curved upper surface.

[0038] In this case, in the display area DA, the area where the sub-pixels SP overlapping with the flat portion 310 of the cover glass 300 are provided may be the first group area GA1, and the area where the sub-pixels SP overlapping with the curved portion 320 of the cover glass 300 are provided may be the second group area GA2. Since the curved portion 320 of the cover glass 300 surrounds the flat portion 310, the second group area GA2 may also surround the first group area GA1. In addition, the second group area GA2 may include at least one unit pixel UP, but it is not limited thereto. In addition, at least one sub-pixel SP may overlap with the boundary area between the flat portion 310 and the curved portion 320, but it is not limited thereto.

[0039] Figure 4 is a cross-sectional view of the sub-pixel SP according to an embodiment of the present invention.

[0040] Referring to Figure 4, a sub-pixel SP according to an embodiment of the present invention may include a substrate 100, a thin film transistor 110, a passivation layer 120, a first planarization layer 130, a connection electrode 135, a second planarization layer 140, a bank 150, a encapsulation layer 160, and a light emitting device OLED.

[0041] The substrate 100 may be formed of glass or plastic, but is not limited thereto. The display device according to an embodiment of the present invention may be configured as a top emission type in which the emitted light is emitted upward. Therefore, as the material of the substrate 100, not only a transparent material but also an opaque material may be used.

[0042] The thin film transistor 110 may be disposed on the substrate 100. The thin film transistor 110 may include a gate electrode 111, a semiconductor layer 112, a gate insulating layer 113, a source electrode 114, and a drain electrode 115.

[0043] The gate electrode 111 of the thin film transistor 110 may be disposed on the substrate 100. In addition, the semiconductor layer 112 may be disposed on the gate electrode 111. The semiconductor layer 112 may include a polysilicon semiconductor or an oxide semiconductor. In addition, when the semiconductor layer 112 includes an oxide semiconductor, it may include at least one oxide of indium gallium zinc oxide (IGZO), indium zinc oxide (IZO), indium gallium tin oxide (IGTO), and indium gallium oxide (IGO).

[0044] In order to insulate the gate electrode 111 from the semiconductor layer 112, a gate insulating layer 113 may be disposed between the gate electrode 111 and the semiconductor layer 112. The gate insulating layer 113 may include a single layer of silicon nitride (SiNx) or silicon oxide (SiOx) or a multi-layer thereof. In addition, Figure 4 The bottom gate structure in which the semiconductor layer 112 is disposed on the gate electrode 111 is illustrated, but is not limited thereto. For example, a top gate structure in which the gate electrode 111 is disposed on the semiconductor layer 112 may be used.

[0045] The source electrode 114 and the drain electrode 115 may be disposed on the semiconductor layer 112 while facing each other. In addition, a passivation layer 120 may be disposed on the source electrode 114 and the drain electrode 115. A contact hole exposing a part of the drain electrode 115 may be formed in the passivation layer 120. In addition, the passivation layer 120 may be formed of an inorganic insulating material such as silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiOxNy).

[0046] The first planarization layer 130 may be disposed on the thin film transistor 110, and the second planarization layer 140 may be disposed on the first planarization layer 130. The first planarization layer 130 and the second planarization layer 140 may compensate for the step difference caused by the thin film transistor 110, thereby planarizing the upper region of the thin film transistor 110. In addition, the first planarization layer 130 and the second planarization layer 140 may be formed of an organic insulating material such as acrylic resin, epoxy resin, phenolic resin, polyamide resin, or polyimide resin.

[0047] The light emitting device OLED may be disposed on the second planarization layer 140. The light emitting device OLED may include a first electrode ANO, a light emitting layer EL, and a second electrode CAT.

[0048] The first electrode ANO is disposed on the second planarization layer 140 and may serve as the anode of the display device. The first electrode ANO may be electrically connected to the drain electrode 115 of the thin film transistor 110 through a connection electrode 135 disposed on the first planarization layer 130.

[0049] The first electrode ANO may include a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). Alternatively, the first electrode ANO may include a metal material such as aluminum (Al), silver (Ag), copper (Cu), molybdenum (Mo), titanium (Ti), tungsten (W), or chromium (Cr), or an alloy thereof. In addition, although illustrated as a single layer, the first electrode ANO may be formed of multiple layers.

[0050] The bank 150 may be disposed on the second planarization layer 140 and the first electrode ANO. The bank 150 may define a light emitting region EA and a non-light emitting region NEA. That is, the region where the bank 150 is not disposed may become the light emitting region EA, and the region where the bank 150 is disposed may become the non-light emitting region NEA.

[0051] The bank 150 may include an organic insulating material such as acrylic resin, epoxy resin, phenolic resin, polyamide resin, polyimide resin, etc. Alternatively, the bank 150 may include an inorganic insulating material such as silicon oxide (SiOx), silicon nitride (SiNx), or silicon oxynitride (SiOxNy). In addition, the bank 150 may include a black dye to absorb light incident from the outside.

[0052] The light emitting layer EL may be disposed on the first electrode ANO. The light emitting layer EL may also be disposed on the bank 150. That is, the light emitting layer EL may be disposed in the light emitting region EA and the non-light emitting region NEA.

[0053] The light-emitting layer EL may include a hole transport layer, an organic light-emitting layer, and an electron transport layer. In this case, when a voltage is applied to the first electrode ANO and the second electrode CAT, holes and electrons move to the organic light-emitting layer through the hole transport layer and the electron transport layer, respectively, and may combine with each other in the organic light-emitting layer to emit light.

[0054] The second electrode CAT may be disposed on the light-emitting layer EL. The second electrode CAT may serve as the cathode of the display device. Similar to the light-emitting layer EL, the second electrode CAT may be disposed in the light-emitting area EA and the non-light-emitting area NEA.

[0055] Since the display device according to an embodiment of the present invention is configured in an upward light-emitting method, the second electrode CAT may include a transparent conductive material such as ITO (indium tin oxide) or IZO (indium zinc oxide) to transmit the light emitted from the light-emitting layer EL upward.

[0056] The encapsulation layer 160 may be disposed on the light-emitting device OLED. The encapsulation layer 160 may include an organic insulating material such as an acrylic resin, an epoxy resin, a phenolic resin, a polyamide resin, or a polyimide resin.

[0057] Figure 5 (a) to (c) are curves of the wavelength λ and the luminance I of the sub-pixel SP in the first group of regions GA1 according to an embodiment of the present invention based on the viewing angle θ. Figure 5 The luminance I shown in (a) to (c) is a view illustrating the luminance of the light generated in the sub-pixel SP in the first group of regions GA1 and passing through the flat portion 310 of the cover glass 300.

[0058] Figure 5 (a) to (c) illustrate the change in the wavelength band of the light emitted from the red sub-pixel SP_R, the green sub-pixel SP_G, and the blue sub-pixel SP_B disposed in the first group of regions GA1 of the display area DA based on the viewing angle θ.

[0059] The viewing angle θ may be the angle between the normal line based on the substrate 100 and the viewing position of the user. The viewing angle θ may include a first viewing angle θ1, a second viewing angle θ2, and a third viewing angle θ3. The second viewing angle θ2 may be greater than the first viewing angle θ1, and the third viewing angle θ3 may be greater than the second viewing angle θ2. In addition, the third viewing angle θ3 may be 60° or less. For example, the first viewing angle θ1 may be 0°, the second viewing angle θ2 may be 30°, and the third viewing angle θ3 may be 45°. That is, the first viewing angle θ1 may be the direction perpendicular to the upper surface of the substrate 100.

[0060] Refer to Figure 5In (a), the red sub-pixel SP_R can emit red light with a wavelength greater than or equal to approximately 600 nm and less than or equal to 650 nm. Refer to Figure 5 In (b), the green sub-pixel SP_G can emit green light with a wavelength greater than or equal to approximately 500 nm and less than or equal to 550 nm. Additionally, refer to Figure 5 In (c), the blue sub-pixel SP_B can emit blue light with a wavelength greater than or equal to 400 nm and less than or equal to 480 nm.

[0061] Refer to Figure 5 In (a) to (c), as the viewing angle gradually changes from the first viewing angle θ1 to the second viewing angle θ2, the brightness curves of the red sub-pixel SP_R, the green sub-pixel SP_G, and the blue sub-pixel SP_B can shift to the left. That is, as the viewing angle changes from the first viewing angle θ1 to the second viewing angle θ2, the wavelength ranges of the red sub-pixel SP_R, the green sub-pixel SP_G, and the blue sub-pixel SP_B can move to a relatively shorter wavelength region. Additionally, as the viewing angle changes from the first viewing angle θ1 to the second viewing angle θ2, the brightness I of the red sub-pixel SP_R, the green sub-pixel SP_G, and the blue sub-pixel SP_B decreases.

[0062] Furthermore, as the viewing angle gradually changes from the second viewing angle θ2 to the third viewing angle θ3, the brightness curves of the red sub-pixel SP_R, the green sub-pixel SP_G, and the blue sub-pixel SP_B can shift to the left. That is, as the viewing angle gradually changes from the second viewing angle θ2 to the third viewing angle θ3, the wavelength ranges of the red sub-pixel SP_R, the green sub-pixel SP_G, and the blue sub-pixel SP_B can move to a relatively shorter wavelength region. Additionally, as the viewing angle gradually changes from the second viewing angle θ2 to the third viewing angle θ3, the brightness I of the red sub-pixel SP_R, the green sub-pixel SP_G, and the blue sub-pixel SP_B decreases.

[0063] That is, as the magnitude of the viewing angle θ increases, the wavelength ranges of all sub-pixels SP move to a relatively shorter wavelength region. Additionally, as the magnitude of the viewing angle θ increases, the brightness I of all sub-pixels SP decreases.

[0064] In this case, the ranges in which the wavelength bands of the red sub-pixel SP_R, the green sub-pixel SP_G, and the blue sub-pixel SP_B move toward the short-wavelength region may be different. Specifically, refer to Figure 5 In (a) to (c), the changes in the wavelength bands can increase in the order of the blue sub-pixel SP_B, the green sub-pixel SP_G, and the red sub-pixel SP_R. That is, based on the viewing angle θ, the change in the wavelength band of the red sub-pixel SP_R can be the largest, and the change in the wavelength band of the blue sub-pixel SP_B can be the smallest. Additionally, the change in the wavelength band of the green sub-pixel SP_G can be between the change in the wavelength band of the red sub-pixel SP_R and the change in the wavelength band of the blue sub-pixel SP_B.

[0065] When the changes in the wavelength bands based on the viewing angle θ of each of the red sub-pixel SP_R, green sub-pixel SP_G, and blue sub-pixel SP_B are similar, color balance can be maintained even when the overall brightness decreases. However, as described above, the changes in the wavelength bands based on the viewing angle θ of each of the red sub-pixel SP_R, green sub-pixel SP_G, and blue sub-pixel SP_B may be different. Therefore, as the viewing angle θ increases, the balance of red light, green light, and blue light cannot be maintained, and thus color difference may occur. For example, when the brightness of blue light is relatively small compared to the brightness of red light and green light, a yellowish color may be achieved.

[0066] Figure 6 (a) to (f) of are the luminance I curves of the sub-pixels SP in the first group of regions GA1 and the second group of regions GA2 according to an embodiment of the present invention. In this case, compared with the viewing angles of the luminance I curves of (a) to (c) of Figure 5 the reference viewing angle of the luminance I curves of (a) to (f) of Figure 6 can be a larger angle. In this case, the larger angle can be 60° or more and 80° or less.

[0067] Figure 6 (a) to (c) of show the luminance I based on the wavelength λ of the light generated by the red sub-pixel SP_R, green sub-pixel SP_G, and blue sub-pixel SP_B provided in the first group of regions GA1 of the display area DA and passing through the flat portion 310 of the cover glass 300.

[0068] Referring to Figure 6 (a) of, the red sub-pixel SP_R can emit red light with a wavelength greater than or equal to about 600 nm and less than or equal to 650 nm. In addition, the peak of the luminance I of the red light emitted from the red sub-pixel SP_R provided in the first group of regions GA1 can be referred to as the first red luminance value R1.

[0069] Referring to Figure 6 (b) of, the green sub-pixel SP_G can emit green light with a wavelength greater than or equal to about 500 nm and less than or equal to 550 nm. In addition, the peak of the luminance I of the green light emitted from the green sub-pixel SP_G provided in the first group of regions GA1 can be referred to as the first green luminance value G1.

[0070] Referring to Figure 6 (c) of, the blue sub-pixel SP_B can emit blue light with a wavelength greater than or equal to about 400 nm and less than or equal to 480 nm. In addition, the peak of the luminance I of the blue light emitted from the blue sub-pixel SP_B provided in the first group of regions GA1 can be referred to as the first blue luminance value B1.

[0071] As described above, the light emitted from the sub-pixels SP in the first group of regions GA1 can pass through the flat portion 310 of the cover glass 300, and the light emitted from the sub-pixels SP in the second group of regions GA2 can pass through the curved portion 320 of the cover glass 300. In this case, since the upper surfaces of the flat portion 310 and the curved portion 320 have different shapes, the paths of the light emitted from the sub-pixels SP in each of the first group of regions GA1 and the second group of regions GA2 may be different.

[0072] Specifically, when the light generated in the first group of regions GA1 is emitted toward the flat portion 310 of the cover glass 300, total internal reflection occurs at a relatively large angle. That is, some of the light is not emitted to the outside but is reflected back toward the substrate 100. Therefore, as described in (a) to (c) above, when the viewing angle increases, the brightness of the red light, green light, and blue light in the flat portion 310 of the cover glass 300 decreases. Figure 5 As described in (a) to (c) above, when the viewing angle increases, the brightness of the red light, green light, and blue light in the flat portion 310 of the cover glass 300 decreases.

[0073] On the other hand, when a part of the light generated in the second group of regions GA2 is emitted toward the curved portion 320 of the cover glass 300, total internal reflection does not occur at a relatively large angle. That is, even at a relatively large angle, a part of the light generated in the second group of regions GA2 can pass through the curved portion 320 of the cover glass 300 and be emitted to the outside. Therefore, the brightness of a specific wavelength band in the curved portion 320 of the cover glass 300 increases. Therefore, the brightness I curves of the sub-pixels SP in the first group of regions GA1 and the sub-pixels SP in the second group of regions GA2 may be different from each other.

[0074] Specifically, Figure 6 (d) to (f) of illustrate the brightness I based on the wavelength λ of the light generated by the red sub-pixel SP_R, green sub-pixel SP_G, and blue sub-pixel SP_B provided in the second group of regions GA2 of the display area DA and passing through the curved portion 320 of the cover glass 300.

[0075] Referring to Figure 6 (d), the peak of the brightness I of the red light emitted from the red sub-pixel SP_R in the second group of regions GA2 can be referred to as the second red brightness value R2. In this case, the second red brightness value R2 can be greater than the first red brightness value R1.

[0076] Referring to Figure 6 (e), the peak of the brightness I of the green light emitted from the green sub-pixel SP_G in the second group of regions GA2 can be referred to as the second green brightness value G2. In this case, the second green brightness value G2 can be greater than the first green brightness value G1.

[0077] Referring to Figure 6In (f), the peak of the luminance I of the blue light emitted from the blue sub-pixels SP_B in the second group of regions GA2 can be referred to as the second blue luminance value B2. In this case, the second blue luminance value B2 can be less than the first blue luminance value B1.

[0078] That is to say, when the viewing angle is a large angle, compared with the first group of regions GA1, the luminance of the red light and the green light increases and the luminance of the blue light decreases in the second group of regions GA2. Therefore, chromatic aberration also occurs in the second group of regions GA2 when the viewing angle is a large angle. Specifically, when the viewing angle is a large angle, a light yellow color can be achieved in the curved portion 320 of the cover glass 300 and at the same time it has a higher luminance than the light of the flat portion 310 of the cover glass 300.

[0079] To improve Figure 5 and Figure 6 the above-described color change, the present invention discloses a display device 1000 including an optical layer 200. This will be described with reference to Figure 7 below.

[0080] Figure 7 is a cross-sectional view of a display device 1000 according to an embodiment of the present invention. As described above in Figure 1 the display device 1000 may have a structure in which a display unit 10, an optical layer 200, and a cover glass 300 are sequentially provided.

[0081] As described above, the display unit 10 may include a display area DA and a non-display area NDA surrounding the display area DA. In addition, a plurality of sub-pixels SP may be provided in the display area DA.

[0082] As described above in Figure 4 each of the plurality of sub-pixels SP includes a light-emitting device OLED provided on a substrate 100, and a packaging layer 160 may cover the light-emitting device OLED. In Figure 7 the detailed structure of each sub-pixel SP will be omitted.

[0083] In this case, the substrate 100 and the packaging layer 160 may be provided in the display area DA and the non-display area NDA, and the light-emitting device OLED of each sub-pixel SP may be provided in the display area DA. In addition, the light-emitting device OLEDs of each sub-pixel SP may be separated from each other by a bank (not shown).

[0084] Light-emitting device OLEDs of a plurality of sub-pixels SP are provided in each of the first group of regions GA1 and the second group of regions GA2. Figure 7 illustrates that two light-emitting device OLEDs are respectively provided on one side and the other side of the first group of regions GA1, but the present invention is not limited thereto.

[0085] The cover glass 300 may be disposed on the display unit 10. Since the cover glass 300 transmits the light emitted from the display unit 10, the cover glass 300 may be formed of a transparent material. The cover glass 300 may include a flat portion 310 and a curved portion 320 surrounding the flat portion 310. The upper surface and the lower surface of the flat portion 310 may be flat. In addition, the upper surface of the curved portion 320 may have a curvature, and the lower surface of the curved portion 320 may be flat.

[0086] The flat portion 310 of the cover glass 300 may cover the entire first group region GA1 of the display unit 10. In addition, the area of the flat portion 310 of the cover glass 300 may be larger than the area of the first group region GA1 of the display unit 10.

[0087] The curved portion 320 of the cover glass 300 may cover the second group region GA2 and the non-display region NDA of the display unit 10. The curved portion 320 of the cover glass 300 may cover the entire second group region GA2 or only cover a partial region of the second group region GA2. For example, in the second group region GA2, at least one light-emitting device OLED may be disposed in the boundary region between the flat portion 310 and the curved portion 320.

[0088] The optical layer 200 may be disposed between the display unit 10 and the cover glass 300. The optical layer 200 may cover the entire upper surface of the display unit 10. In addition, the cover glass 300 may cover the entire upper surface of the optical layer 200.

[0089] The optical layer 200 may include a first region 210 and a second region 220 surrounding the first region 210.

[0090] The first region 210 of the optical layer 200 may correspond to the flat portion 310 of the cover glass 300. The area of the upper surface of the first region 210 of the optical layer 200 may be the same as the area of the lower surface of the flat portion 310 of the cover glass 300. That is, since the flat portion 310 overlaps with the entire first group region GA1 of the display unit 10, the first region 210 may also overlap with the entire first group region GA1 of the display unit 10. In addition, when the area of the flat portion 310 is larger than the area of the first group region GA1 of the display unit 10, the area of the first region 210 may also be larger than the area of the first group region GA1 of the display unit 10. That is, the sub-pixels SP of the first group region GA1 may overlap with both the first region 210 of the optical layer 200 and the flat portion 310 of the cover glass 300.

[0091] The first region 210 of the optical layer 200 may include a liquid crystal material 211 and a dichroic dye 212. The liquid crystal material 211 may be a liquid crystal material including a polymerizable end group. For example, the liquid crystal material 211 may include a mesogen exhibiting liquid crystal properties and a polymerizable end group. In addition, the liquid crystal material 211 may be aligned in a direction perpendicular to the substrate 100. In this case, since the dichroic dye 212 is aligned in the same direction as the liquid crystal material 211, the dichroic dye 212 may also be aligned in a direction perpendicular to the substrate 100.

[0092] The dichroic dye 212 may absorb light in a specific wavelength band. For example, the dichroic dye 212 may absorb light in a wavelength band of more than 500 nm and less than 650 nm. That is, the dichroic dye 212 may absorb light in the red wavelength band and the green wavelength band.

[0093] Therefore, when light emitted from a plurality of light-emitting devices OLED is directed to the liquid crystal material 211, the light may pass through the liquid crystal material 211 and be emitted to the outside. In addition, when light emitted from a plurality of light-emitting devices OLED is directed to the dichroic dye 212, light in a specific wavelength band may be absorbed by the dichroic dye 212, and the remaining wavelength band of light may pass through the dichroic dye 212 and be emitted to the outside.

[0094] As described above, the liquid crystal material 211 and the dichroic dye 212 may be aligned in a direction perpendicular to the substrate 100. Therefore, among the light emitted from a plurality of light-emitting devices OLED, light incident on the first region 210 of the optical layer 200 in a direction having a predetermined angle is more likely to be directed to the dichroic dye 212 than light incident on the first region 210 of the optical layer 200 in a direction perpendicular to the first region 210. For example, light emitted from a plurality of light-emitting devices OLED may be incident on the first region 210 in a direction having an angle of 60° or less.

[0095] That is, among the light emitted from a plurality of light-emitting devices OLED, light incident on the first region 210 in a direction having a predetermined angle is more likely to be absorbed by the dichroic dye 212 than light incident on the first region 210 in a perpendicular direction.

[0096] As above in Figure 5As described in [reference], chromatic aberration may occur in the flat portion 310 of the cover glass 300 as the viewing angle increases within the range of 0° to 60°. However, according to the present invention, by forming the optical layer 200 having the dichroic dye 212 in the region corresponding to the flat portion 310 of the cover glass 300, the light incident on the first region 210 of the optical layer 200 in a direction having a predetermined angle can be absorbed. For example, in the first group of regions GA1, when the brightness of blue light is relatively small compared to the brightness of red light and green light, the dichroic dye 212 can be formed to absorb red light and green light. Therefore, the brightness of red light and green light can be reduced, and thus the brightness of red light, green light, and blue light can be similar to each other. Therefore, by maintaining the balance of red light, green light, and blue light, the chromatic aberration based on the viewing angle of the flat portion 310 can be minimized.

[0097] The second region 220 of the optical layer 200 may correspond to the curved portion 320 of the cover glass 300. The area of the upper surface of the second region 220 of the optical layer 200 may be the same as the area of the lower surface of the curved portion 320 of the cover glass 300. That is, since the curved portion 320 of the cover glass 300 covers the second group of regions GA2 and the non-display region NDA of the display unit 10, the second region 220 of the optical layer 200 may also cover the second group of regions GA2 and the non-display region NDA of the display unit 10.

[0098] The second region 220 of the optical layer 200 may include a first portion 220a overlapping with the second group of regions GA2 and a second portion 220b overlapping with the non-display region NDA. In addition, when the curved portion 320 of the cover glass 300 covers the entire second group of regions GA2, the first portion 220a of the second region 220 of the optical layer 200 may also cover the entire second group of regions GA2. Alternatively, when the curved portion 320 of the cover glass 300 only covers a part of the second group of regions GA2, the first portion 220a of the second region 220 of the optical layer 200 may also only cover a part of the second group of regions GA2. That is, in the second group of regions GA2, at least one light-emitting device OLED may overlap both the boundary region between the flat portion 310 and the curved portion 320 and the boundary region between the first region 210 and the second region 220.

[0099] The second region 220 of the optical layer 200 may include a cholesteric liquid crystal 221. The cholesteric liquid crystal 221 may be distributed in both the first portion 220a and the second portion 220b of the second region 220. The cholesteric liquid crystal 221 may have a helical structure in which the optical axes of the liquid crystal molecules in each layer are misaligned with the optical axes of the liquid crystal molecules in the adjacent layer. When the liquid crystal molecules of the cholesteric liquid crystal 221 have a rod shape, the optical axis of the liquid crystal molecules may correspond to the long axis of the liquid crystal molecules, such that the optical axis and the absorption axis may be perpendicular to each other.

[0100] In this case, since the cholesteric liquid crystal 221 does not receive an electric field, the cholesteric liquid crystal 221 can be in a planar state. Therefore, the cholesteric liquid crystal 221 can reflect light in a specific wavelength range.

[0101] Specifically, the reference wavelength range Δλ of the light reflected by the cholesteric liquid crystal 221 r can be defined by Equation 1 below. In this case, the reference wavelength range Δλ r refers to the wavelength range of the light reflected when the light is perpendicularly incident on the cholesteric liquid crystal 221. That is, when light having a wavelength corresponding to the range of Equation 1 is perpendicularly incident on the cholesteric liquid crystal 221, the light can be reflected by the cholesteric liquid crystal 221.

[0102] Equation 1: Δλ r = PΔn

[0103] In this case, P can be the distance at which the optical axis of the liquid crystal molecules in the cholesteric liquid crystal 221 makes a 360° rotation, that is, the pitch. In addition, Δn can be the difference between the refractive index of the cholesteric liquid crystal 221 with respect to light polarized parallel to the optical axis of the cholesteric liquid crystal 221 and the refractive index of the cholesteric liquid crystal 221 with respect to light polarized perpendicular to the optical axis of the cholesteric liquid crystal 221.

[0104] In addition, the central wavelength λ0 of the light reflected by the cholesteric liquid crystal 221 can be defined by Equation 2 below. The central wavelength λ0 can be the central value of the reference wavelength range Δλ r

[0105] Equation 2: λ0 = 0.5NP

[0106] In this case, N can be the sum of the refractive index of the cholesteric liquid crystal 221 with respect to light polarized parallel to the optical axis of the cholesteric liquid crystal 221 and the refractive index of the cholesteric liquid crystal 221 with respect to light polarized perpendicular to the optical axis of the cholesteric liquid crystal 221.

[0107] That is, the cholesteric liquid crystal 221 can adjust the central wavelength λ0 and the reference wavelength range Δλ by adjusting the pitch P r

[0108] In this case, since the cholesteric liquid crystal 221 has a helical structure, the reflection wavelength range can change according to the angle of the incident light. That is, as the viewing angle increases, the reflection wavelength range of the cholesteric liquid crystal 221 can change.

[0109] Specifically, when the viewing angle is a large angle of 60° or more and 80° or less, compared with the reference wavelength range Δλ r ​​In contrast, the reflection wavelength range of the cholesteric liquid crystal 221 can be shifted to a relatively shorter wavelength region. For example, the central wavelength λ0 of the cholesteric liquid crystal 221 can be about 750 nm. That is to say, the reference wavelength range Δλ of the cholesteric liquid crystal 221 r can be in the infrared region. In this case, when the viewing angle is a large angle, the reflection wavelength range of the cholesteric liquid crystal 221 can be shifted to a region above 500 nm and below 650 nm. That is to say, when the viewing angle is a large angle, the cholesteric liquid crystal 221 can reflect light in the red wavelength band and the green wavelength band. The light reflected by the cholesteric liquid crystal 221 can be emitted toward the substrate 100.

[0110] As described above in Figure 6 , when the viewing angle is a large angle, a pale yellow color can be achieved on the curved portion 320 of the cover glass 300. However, according to the present invention, by forming the optical layer 200 having the cholesteric liquid crystal 221 in the region corresponding to the curved portion 320 of the cover glass 300, the light incident from the display unit 10 onto the second region 220 of the optical layer 200 can be reflected. In particular, in the large angle direction above 60° and below 80°, the red light and the green light incident from the display unit 10 onto the second region 220 of the optical layer 200 can be reflected. Therefore, the brightness of the red light and the green light can be reduced, and thus the brightness of the red light, the green light, and the blue light can be similar to each other. Therefore, by maintaining the balance of the red light, the green light, and the blue light, the viewing angle-based color difference of the curved portion 320 can be minimized.

[0111] In addition, since the reference wavelength range Δλ of the cholesteric liquid crystal 221 r is in the infrared region, the light in the visible light region incident on the cholesteric liquid crystal 221 from the display unit 10 in the vertical direction and at a small angle can be transmitted. Therefore, the brightness of the light pointing in the vertical direction and at a small angle can be unaffected.

[0112] Figure 8 (a) to (d) of Figure 8 show curves of the color change of the sub-pixels SP based on the viewing angle θ in the first group of regions GA1 and the second group of regions GA2 according to an embodiment of the present invention. Referring to

[0113] (a) to (d) of

[0114] In this case, Ref is a structure in which the cover glass 300 is directly disposed on the display unit 10, and E1 is a structure in which an optical layer 200 is disposed between the display unit 10 and the cover glass 300 as described above. Figure 7 in the structure.

[0115] Figure 8 (a) and (b) of FIG. illustrate the color change of light generated by the sub-pixels SP in the first set of regions GA1 and passing through the flat portion 310 of the cover glass 300. The first viewing angle θ1 can be 0°, and the second viewing angle θ2 can be greater than the first viewing angle θ1. For example, the second viewing angle θ2 can be 45°.

[0116] At the first viewing angle θ1, since Figure 8 the points of (a) and (b) of FIG. are at the origin, the color balance can be maintained.

[0117] At the second viewing angle θ2, Figure 8 the point of (a) of FIG. can move between the red direction R and the green direction G. Therefore, at the second viewing angle θ2, the structure of Ref can have relatively higher brightness of red light and green light than the brightness of blue light. On the other hand, at the second viewing angle θ2, Figure 8 the point of (b) of FIG. can be closer to the origin than Figure 8 the point of (a) of FIG. Therefore, compared with the structure of Ref, even when the viewing angle increases in the first set of regions GA1, the structure of E1 including the optical layer 200 can minimize the color change.

[0118] Figure 8 (c) and (d) of FIG. illustrate the color change of light generated by the sub-pixels SP in the second set of regions GA2 and passing through the curved portion 320 of the cover glass 300. The first viewing angle θ1 can be 0°, and the third viewing angle θ3 can be greater than the second viewing angle θ2. For example, the third viewing angle θ3 can be 75°.

[0119] At the first viewing angle θ1, Figure 8 the points of (c) and (d) of FIG. maintain the position of the origin, so that the color balance can be maintained.

[0120] At the third viewing angle θ3, Figure 8 the point of (c) of FIG. can move between the red direction R and the green direction G. Therefore, at the third viewing angle θ3, the structure of Ref can have relatively higher brightness of red light and green light than the brightness of blue light. In addition, Figure 8 the range in which the point of the third viewing angle θ3 in (c) of FIG. moves from the origin can be greater than Figure 8 the range in which the point of the second viewing angle θ2 in (a) of FIG. moves from the origin. That is, compared with the first set of regions GA1, the color change can be greater in the second set of regions GA2.

[0121] On the other hand, at the third viewing angle θ3, Figure 8 the point of (d) is closer to the origin than Figure 8 the point of (c). Therefore, compared with the structure of Ref, even when the viewing angle increases in the second group of regions GA2, the structure including E1 of the optical layer 200 can minimize color change.

[0122] Therefore, according to the present invention, by forming the optical layer 200 between the display unit 10 and the cover glass 300 having the flat portion 310 and the curved portion 320, the color change of the flat portion 310 and the curved portion 320 can be minimized.

[0123] Figure 9 is a cross-sectional view of a display device according to another embodiment of the present invention.

[0124] Compared with Figure 7 it discloses a substantially identical structure, except for the optical layer 200. Therefore, the same reference numerals are used for the same components as those in the display device 1000 shown in Figure 9 and repeated descriptions are omitted. Figure 7 Referring to

[0125] Figure 9 the optical layer 200 may include a first region 210 and a second region 220. In this case, Figure 7 the first region 210 of the optical layer 200 of Figure 9 includes a liquid crystal material 211 and a dichroic dye 212, while

[0126] in Figure 7 the first region 210 of the optical layer 200 of Figure 9 may include only the liquid crystal material 211.

[0127] It is obvious to those skilled in the art that the above disclosure is not limited to the above embodiments and drawings, and various substitutions, modifications and changes can be made to the present invention without departing from the spirit or scope of the present invention. Thus, the scope of the present invention is defined by the appended claims, and all changes or modifications derived from the meaning, scope and equivalent concepts of the claims fall within the scope of the present invention.​

Claims

1. A display device, comprising: A display unit, the display unit comprising a display area provided with a plurality of sub-pixels and a non-display area surrounding the display area; an optical layer disposed on the display unit and comprising cholesteric liquid crystal; and A cover glass disposed on the optical layer, The cover glass includes a flat portion and a curved portion disposed outside the flat portion, and the cholesteric liquid crystal overlaps the curved portion. 2 . The display device according to claim 1 , wherein the cholesteric liquid crystal reflects light in an infrared region incident on the cholesteric liquid crystal from the display unit in a direction of a normal line perpendicular to a substrate of the display unit. 3 . The display device according to claim 2 , wherein the cholesteric liquid crystal transmits light in an infrared region incident on the cholesteric liquid crystal from the display unit in a direction having an angle of 60° or more and 80° or less with the normal line. 4 . The display device according to claim 1 , wherein the cholesteric liquid crystal transmits light in a visible light region incident on the cholesteric liquid crystal from the display unit in a direction of a normal line perpendicular to a substrate of the display unit.

5. The display device according to claim 4, wherein the cholesteric liquid crystal transmits a portion of light in a visible light region incident on the cholesteric liquid crystal from the display unit in a direction having an angle of 60° or more and 80° or less with respect to the normal line, and reflects a remaining portion of light in a visible light region incident on the cholesteric liquid crystal from the display unit in a direction having an angle of 60° or more and 80° or less with respect to the normal line.

6. The display device according to claim 5, wherein the cholesteric liquid crystal transmits blue light incident on the cholesteric liquid crystal from the display unit in a direction having an angle of 60° or more and 80° or less with respect to the normal line, and reflects red light and green light incident on the cholesteric liquid crystal from the display unit in a direction having an angle of 60° or more and 80° or less with respect to the normal line. 7 . The display device according to claim 1 , wherein the optical layer includes a first region and a second region disposed outside the first region, and the cholesteric liquid crystal is disposed in the second region. 8 . The display device according to claim 7 , wherein the first area overlaps with the flat portion, and the second area overlaps with the curved portion. 9 . The display device according to claim 8 , wherein an area of ​​an upper surface of the first region is the same as an area of ​​a lower surface of the flat portion, and an area of ​​an upper surface of the second region is the same as an area of ​​a lower surface of the curved portion. 10 . The display device of claim 7 , wherein the second area includes a first portion overlapping the display area and a second portion overlapping the non-display area. 11 . The display device according to claim 7 , wherein the first region includes a liquid crystal material arranged in a direction perpendicular to a substrate of the display unit. 12 . The display device according to claim 11 , wherein the first region further comprises a dichroic dye, and the dichroic dye is arranged in a direction perpendicular to the substrate. 13 . The display device according to claim 12 , wherein the dichroic dye absorbs light in a red wavelength range and a green wavelength range.

14. The display device according to claim 1, wherein the display area includes a first group of areas overlapping the flat portion and a second group of areas overlapping the curved portion, and A plurality of sub-pixels are disposed in each of the first group of regions and the second group of regions. The display device according to claim 14 , wherein the flat portion covers the entire first group of regions. 16 . The display device according to claim 14 , wherein the bent portion covers the entire non-display area and a portion of the second group of areas. 17 . The display device according to claim 16 , wherein at least one sub-pixel among the plurality of sub-pixels overlaps a boundary region between the flat portion and the curved portion. 18 . The display device according to claim 1 , wherein a lower surface of the curved portion is flat, and an upper surface of the curved portion is curved. 19 . The display device according to claim 18 , wherein a thickness of the bent portion decreases from a boundary area between the planar portion and the bent portion toward an end of the bent portion.

20. A display device, comprising: A substrate, the substrate comprising a display area provided with a plurality of sub-pixels and a non-display area surrounding the display area; a light emitting device disposed on the substrate and disposed in each of the plurality of sub-pixels; an encapsulation layer disposed in the display area and the non-display area and covering the light emitting device; An optical layer disposed on the encapsulation layer, the optical layer comprising a first region and a second region having a property different from that of the first region; and A cover glass disposed on the optical layer, the cover glass comprising a flat portion and a curved portion, wherein the entire first area of ​​the optical layer corresponds to the display area, and The second area of ​​the optical layer includes a first portion corresponding to the display area and a second portion corresponding to the non-display area. 21 . The display device of claim 20 , wherein the second region of the optical layer comprises cholesteric liquid crystal. 22 . The display device of claim 20 , wherein the first region of the optical layer includes a liquid crystal material aligned in a direction perpendicular to the substrate. 23 . The display device of claim 22 , wherein the first region of the optical layer further comprises a dichroic dye aligned in the same direction as the liquid crystal material. 24 . The display device of claim 20 , wherein the first portion and the second portion of the second region of the optical layer correspond to the curved portion of the cover glass. 25 . The display device of claim 20 , wherein the entire first region of the optical layer corresponds to the flat portion of the cover glass.

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