Display device

Abstract

This disclosure relates to a display device, and according to an aspect of this disclosure, the display device includes: a display panel, a polarizing film disposed on the display panel, and a plurality of retardation films disposed on the polarizing film and having different in-plane phase differences Rin, wherein the in-plane phase difference Rin of each of the plurality of retardation films is 10000 nm or greater. According to exemplary embodiments of this disclosure, color distortion such as color irregularities, color shifts, and interference colors is improved, and the recognition of rainbow spots is minimized.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2021-0174895, filed on December 8, 2021, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to display devices, and more specifically, to display devices that improve rainbow spots to have excellent display quality and can be easily implemented as flexible display devices. Background Technology

[0004] As the display field has entered the information age, the field of displays that visually express electrical information signals has developed rapidly. In response, various display devices with superior performance, such as thinness, light weight, and low power consumption, have been developed. Specific examples of such display devices include liquid crystal displays (LCDs), plasma display panels (PDPs), field emission displays (FEDs), and organic light-emitting diode displays (OLEDs).

[0005] Among various display devices, organic light-emitting diode (OLED) displays do not require a separate light source. Therefore, OLED displays can be manufactured to be lightweight and thin, offering advantages in manufacturing processes and low power consumption due to low-voltage operation. Firstly, OLED displays include self-emissive elements and a layer formed from an organic thin film, resulting in superior flexibility and elasticity compared to other display devices, making it advantageous to realize them as flexible display devices.

[0006] Typically, in organic light-emitting display devices, in order to suppress the degradation of visibility and contrast caused by light incident from the outside into the display device, a polarizing film is provided on the display panel, and a protective film is provided to protect the polarizing film. Summary of the Invention

[0007] In existing display devices, polyethylene terephthalate (PET) film is primarily laminated to protect the polarizing film. PET film is inexpensive and has excellent durability, but its birefringence properties cause a reduction in display quality due to optical distortion when used as a protective film.

[0008] To reduce optical distortion, a high-retardation film, known as stretched PET film or ultra-retardation film (SFR), is laminated onto the polarizing film. However, in this case, rainbow stains are visible when a user wears polarized sunglasses and views the image on the display device, thus reducing display quality (the so-called "rainbow effect").

[0009] Therefore, the purpose of this disclosure is to provide a display device that has excellent display quality by minimizing or reducing the visibility of rainbow spots.

[0010] Furthermore, the purpose of this disclosure is to provide a display device that maintains high display quality while exhibiting excellent folding reliability, so as to be implemented as various flexible display devices such as foldable or rollable display devices.

[0011] The purpose of this disclosure is not limited to the purposes mentioned above, and other purposes not mentioned above will be clearly understood by those skilled in the art from the following description.

[0012] According to an aspect of this disclosure, a display device includes: a display panel, a polarizing film disposed on the display panel, and a plurality of retardation films disposed on the polarizing film and having different in-plane phase differences Rin, wherein the in-plane phase difference Rin of each of the plurality of retardation films is 10000 nm or greater.

[0013] Further details of the exemplary embodiments are included in the detailed description and accompanying drawings.

[0014] According to exemplary embodiments of this disclosure, color distortions such as color irregularities, color shifts, and interfering colors are improved, and the visibility of rainbow spots is minimized or reduced.

[0015] According to an exemplary embodiment of this disclosure, the rainbow spots are not visible from the front and from a horizontal viewing angle, making it possible to provide a display device with excellent display quality.

[0016] Furthermore, according to exemplary embodiments of this disclosure, folding reliability is ensured while maintaining excellent display quality, enabling the realization of various types of flexible display devices.

[0017] The effects of this disclosure are not limited to those illustrated above, and include a variety of other effects as described in this specification. Attached Figure Description

[0018] The above and other aspects, features and other advantages of this disclosure will become clearer from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0019] Figure 1 This is a cross-sectional view of a display device according to an exemplary embodiment of the present disclosure;

[0020] Figure 2 The optical axes of the first retardation film, the second retardation film, and the polarizing film in the plane are shown.

[0021] Figure 3This shows an in-plane phase difference R with a diameter of 137.5 nm. in PET film and in-plane phase difference R with 3000nm in A graph showing the relationship between the transmittance of PET film laminates and wavelength;

[0022] Figure 4 The image shows the effect of wearing polarized sunglasses and viewing an image including those with polarized sunglasses. Figure 3 A diagram shown to a user of a display device of an exemplary embodiment of a laminate with the indicated transmittance;

[0023] Figure 5 This is a graph showing the relationship between the transmittance of the SRF film and the wavelength;

[0024] Figure 6 It shows the effect of wearing polarized sunglasses and viewing an image including those with polarized sunglasses. Figure 5 The image shown is what a user of a display device would see of an SRF film with the indicated transmittance.

[0025] Figure 7 This illustrates an exemplary embodiment of the present disclosure when there is an in-plane phase difference R of 10000 nm. in PET film and an in-plane phase difference R of 20000nm in A graph showing the relationship between the transmittance of the laminate and wavelength when PET film is laminated;

[0026] Figure 8 It shows the effect of wearing polarized sunglasses and viewing an image including those with polarized sunglasses. Figure 7 A diagram shown to a user of a display device of an exemplary embodiment of a laminate with the indicated transmittance;

[0027] Figure 9 This shows an in-plane phase difference R with a value of 10000 nm. in PET film and in-plane phase difference R with 3000nm in A graph showing the relationship between the transmittance of PET film laminates and wavelength;

[0028] Figure 10 It shows the effect of wearing polarized sunglasses and viewing an image including those with polarized sunglasses. Figure 9 The image shown is what a user of a display device would see of a laminate with the indicated transmittance.

[0029] Figure 11 This shows an in-plane phase difference R with a value of 20,000 nm. in PET film and in-plane phase difference R with 3000nm in A graph showing the relationship between the transmittance of PET film laminates and wavelength;

[0030] Figure 12It shows the effect of wearing polarized sunglasses and viewing an image including those with polarized sunglasses. Figure 11 The image shown is a display device showing the transmittance of the laminate; and

[0031] Figures 13 to 17 A cross-sectional view of a display device according to another exemplary embodiment of the present disclosure is shown. Detailed Implementation

[0032] The advantages and features of this disclosure, as well as methods for achieving these advantages and features, will become clear from the exemplary embodiments described in detail below with reference to the accompanying drawings. However, this disclosure is not limited to the exemplary embodiments disclosed herein, but can be implemented in various forms. The exemplary embodiments are provided by way of example only to enable those skilled in the art to fully understand the disclosure and scope of this disclosure. Therefore, this disclosure is limited only by the scope of the appended claims.

[0033] The shapes, dimensions, scales, angles, numbers, etc., shown in the accompanying drawings used to describe exemplary embodiments of this disclosure are merely examples, and this disclosure is not limited thereto. Throughout the specification, the same reference numerals generally denote the same elements. Furthermore, in the following description of this disclosure, detailed descriptions of known related technologies may be omitted to avoid unnecessarily obscuring the subject matter of this disclosure. Terms such as “comprising,” “having,” and “consisting of” as used herein are generally intended to allow for the addition of additional 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.

[0034] Even if not explicitly stated, components are interpreted as including the normal tolerance range.

[0035] When using terms such as “on top of,” “above,” “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 following” or “directly.”

[0036] When an element or layer is placed "on" another element or layer, the other layer or element can be directly inserted on or between the other elements.

[0037] Although the terms "first," "second," etc., are used to describe individual components, these components are not limited by these terms. These terms are merely used to distinguish one component from others. Therefore, the first component mentioned below can be a second component in the technical concept of this disclosure.

[0038] Throughout the specification, the same reference numerals generally denote the same elements.

[0039] For ease of description, the dimensions and thickness of each component shown in the accompanying drawings are illustrated, but this disclosure is not limited to the dimensions and thickness of the components shown.

[0040] Features of various embodiments of this disclosure may be partially or completely adhered to or combined with each other, and may be technically interlocked and operated in different ways, and the embodiments may be performed independently of each other or in relation to each other.

[0041] In the following, a display device according to an exemplary embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

[0042] Figure 1 This is a schematic cross-sectional view of a display device according to an exemplary embodiment of the present disclosure. (Refer to...) Figure 1 The display device 100 according to an exemplary embodiment of the present disclosure includes a display panel 110, a polarizing film 120, a plurality of retardation films 141 and 142, a support film 130, a hard coating layer 150, and a plurality of adhesive layers ADH1, ADH2, ADH3, and ADH4.

[0043] Display panel 110 is a component for displaying images. Display panel 110 includes a display area and a non-display area. The display area is an area in which multiple pixels are arranged to substantially display an image. Within the display area, pixels including an emission area for displaying the image and driving circuitry for driving the pixels can be provided. The non-display area is configured to surround the display area. The non-display area is an area that does not display images and is provided with various wiring, driver ICs, and printed circuit boards for driving the pixels and driving circuitry arranged within the display area.

[0044] For example, display panel 110 may be an organic light-emitting display panel that includes organic light-emitting diodes to display images using light emitted from the organic light-emitting diodes. In the following description, for ease of description, the example of a display panel being an organic light-emitting display panel is used, but it is not limited thereto.

[0045] The display panel 110 can be flexible. Therefore, the display panel 110 can be modified in various forms, such as curved, folded, bent, or rolled, while maintaining display quality.

[0046] For example, the display panel 110 may include a flexible substrate, thin-film transistors, and organic light-emitting diodes.

[0047] The flexible substrate supports various components configured for the display panel 110. The flexible substrate 110 may be a flexible plastic substrate. For example, the plastic substrate may be selected from polyimide, polyethersulfone, polyethylene terephthalate, and polycarbonate, but is not limited thereto.

[0048] An organic light-emitting diode (OLED) is disposed on a flexible substrate. The OLED may include an anode, a cathode, and an organic light-emitting layer disposed between the anode and the cathode. In the OLED, holes injected from the anode and electrons injected from the cathode combine on the organic light-emitting layer to emit light. Images can be displayed using the light emitted as described above.

[0049] A driving thin-film transistor (TFT) can be disposed between a flexible substrate and an organic light-emitting diode (OLED) to drive the OLED. The TFT can be disposed in each of a plurality of sub-pixel regions. For example, the TFT may include a gate electrode, an active layer, a source electrode, and a drain electrode.

[0050] A polarizing film 120 is disposed on the display panel 110. The polarizing film 120 selectively transmits light to reduce the reflection of external light incident on the display panel 110. Specifically, the display panel 110 includes various metallic materials used in thin-film transistors, wiring, and organic light-emitting diodes. Therefore, external light incident on the display panel 110 can be reflected from the metallic materials with high reflectivity, causing the visibility of the display device 100 to be reduced due to the reflection of external light. The polarizing film 120 linearly polarizes the external light along a predetermined direction. Therefore, the reflection of external light can be minimized, and the visibility and contrast of the display device 100 can be improved.

[0051] For example, polarizing film 120 can be selected from, but is not limited to, iodine-based polarizing films, dye-based polarizing films, and polyene-based polarizing films. Iodine-based polarizing films are formed by the orientation of polyvinyl alcohol (PVA) chains, in which iodine or iodide ion chains are stretched to exhibit polarization properties. Dye-based polarizing films are formed by the orientation of PVA chains, in which dichroic dyes are stretched to exhibit polarization properties. In contrast, polyene-based polarizing films exhibit polarization properties by forming polyenes through a dehydration reaction of a PVA film or a dehydrochlorination reaction of a polyvinyl chloride (PVC) film. However, the type of polarizing film 120 is not limited to these.

[0052] If necessary, an optional λ / 4 retardation film may be disposed between the display panel 110 and the polarizing film 120. When light reflected by the metal layer reaches the polarizing film 120, the λ / 4 retardation film alters the light path so that it does not pass through the polarizing film 120, thereby reducing the degradation of visibility caused by reflected light.

[0053] The polarizing film 120 can be bonded to the display panel 110 by means of a first adhesive layer ADH1. The first adhesive layer ADH1 can be formed using an optically transparent adhesive for displays, such as a pressure-sensitive adhesive, an optically transparent adhesive, or an optically transparent resin. However, when the polarizing film 120 is formed by forming a liquid coating agent into a film, the first adhesive layer ADH1 can be omitted.

[0054] A support film 130 is disposed on the polarizing film 120. The support film 130 supports a plurality of retardation films 141 and 142, which will be described below. For example, the support film 130 may be a transparent thin film glass or a plastic film. Specifically, for example, the plastic film may be formed of a material selected from, but not limited to, polyethylene terephthalate, polyimide, polymethyl methacrylate, polycarbonate, and polypropylene.

[0055] The support film 130 can be bonded to the polarizing film 120 by means of a second adhesive layer ADH2. For example, the second adhesive layer ADH2 can be formed using an optically transparent adhesive for displays, such as a pressure-sensitive adhesive, an optically transparent adhesive, or an optically transparent resin.

[0056] Multiple retardation films 141 and 142 are disposed on the support film 130. As an example, the multiple retardation films 141 and 142 shown in the figures include a first retardation film 141 and a second retardation film 142, but are not limited thereto.

[0057] A first retardation film 141 is disposed on a support film 130. The first retardation film 141 and the support film 130 can then be bonded together by a third adhesive layer ADH3. For example, an optically transparent adhesive used in displays, such as a pressure-sensitive adhesive, an optically transparent adhesive, or an optically transparent resin, can be used to form the third adhesive layer ADH3.

[0058] A second retardation film 142 is disposed on the first retardation film 141. At this time, a fourth adhesive layer ADH4 can be disposed between the second retardation film 142 and the first retardation film 141. The fourth adhesive layer ADH4 bonds the second retardation film 142 and the first retardation film 141. For example, the fourth adhesive layer ADH4 can be selected from pressure-sensitive adhesives, optically transparent adhesives, and optically transparent resins, but is not limited thereto.

[0059] For example, each of the first retardation film 141 and the second retardation film 142 can be a film formed from any one of the following materials: polyethylene terephthalate, polyethersulfone, polycarbonate, polyimide, polypropylene, cyclic olefin polymers, cyclic olefin copolymers, and polymethyl methacrylate. Desiredly, for example, each of the first retardation film 141 and the second retardation film 142 can be a polyethylene terephthalate film. This has the advantages of being inexpensive, readily available, and easy to control physical properties such as phase difference.

[0060] For example, the in-plane phase difference R of each of the first retardation film 141 and the second retardation film 142 in The in-plane phase difference can be 10,000 nm or higher, and the in-plane phase difference of the first retardation film 141 and the in-plane phase difference of the second retardation film 142 can be different from each other. As described above, when the first retardation film 141 and the second retardation film 142, having different in-plane phase differences of 10,000 nm or greater, are laminated on the polarizing film 120, the rainbow effect is improved, resulting in excellent visibility of the display device 100. Specifically, according to an exemplary embodiment of this disclosure, even if a user views the screen while wearing polarized sunglasses, the rainbow effect will not be detected, and a high-quality image can be viewed.

[0061] For example, the in-plane phase difference of the first retardation film 141 is 10,000 nm to 15,000 nm, and the in-plane phase difference of the second retardation film 142 can be 20,000 nm to 23,000 nm. When the in-plane phase difference of each of the first retardation film 141 and the second retardation film 142 is within the range mentioned above, rainbow spots can be effectively reduced. When the in-plane phase difference is too small, the improvement in visibility and the improvement in rainbow spots may not be significant. Meanwhile, the in-plane phase difference of the first retardation film 141 and the second retardation film 142 can be controlled according to the film stretching ratio, stretching temperature, and thickness. Generally, the higher the stretching ratio, the lower the stretching temperature, and / or the greater the thickness, the higher the in-plane phase difference. Therefore, in order to control the in-plane phase difference between the first retardation film 141 and the second retardation film 142 to a high level, it is necessary to increase the stretching ratio or increase the film thickness. That is, in order to provide a retardation film with a high in-plane phase difference, it is necessary to increase the stretching ratio, which is undesirable due to reduced process efficiency and a decrease in visibility and rainbow spot improvement compared to process efficiency. Furthermore, when the film thickness is too large, the thickness of the display device also increases, potentially limiting its application as a flexible display device, such as a foldable or rollable display device. Therefore, it is desirable to control the in-plane phase difference between the first retardation film 141 and the second retardation film 142 within the range mentioned above.

[0062] For example, the thickness of each of the first retardation film 141 and the second retardation film 142 can be from 30 μm to 120 μm. Within this range, the in-plane phase difference of each film has a value within a desired range to properly maintain the thickness of the display device 100 and ensure folding reliability. Therefore, the display device 100 becomes thin and can be implemented as a flexible display device.

[0063] Furthermore, when the film thickness is too large, the phase difference R in the thickness direction... thIn some cases, the improvement in visibility and rainbow effect of the display device may not be significant. For example, the thickness direction phase difference of each of the first retardation film 141 and the second retardation film 142 may be 0.5 times or less than the in-plane phase difference. For example, when the in-plane phase difference of the first retardation film 141 is 10000 nm, the thickness direction phase difference is 5000 nm or less, and when the in-plane phase difference of the second retardation film 142 is 20000 nm, the thickness direction phase difference is 10000 nm or less. In this case, the visibility and rainbow effect of the display device can be effectively improved.

[0064] Furthermore, to further improve display quality, the optical axis of each of the first retardation film 141, the second retardation film 142, and the polarizing film 120 can be controlled. Referring below... Figure 2 Together, the optical axes of each of the first retardation film 141, the second retardation film 142, and the polarizing film 120 are described. Figure 2 The optical axis in a plane is shown for each of the first retardation film 141, the second retardation film 142, and the polarizing film 120.

[0065] Reference Figure 2 The angle θ1 formed by the optical axis 141A of the first retardation film 141 and the optical axis 142A of the second retardation film 142 can be 90°±10°. The angle θ2 formed by the optical axis 141A of the first retardation film 141 and the optical axis 120A of the polarizing film 120 can be 45°±10° or 135°±10°. The angle θ3 formed by the optical axis 142A of the second retardation film 142 and the optical axis 120A of the polarizing film 120 can be 45°±10° or 135°±10°. That is, when the angle θ2 formed by the optical axis 141A of the first retardation film 141 and the optical axis 120A of the polarizing film 120 is 45°±10°, the angle θ3 formed by the optical axis 142A of the second retardation film 142 and the optical axis 120A of the polarizing film 120 can be 135°±10°. Conversely, when the angle θ3 formed by the optical axis 142A of the second retardation film 142 and the optical axis 120A of the polarizing film 120 is 45°±10°, the angle θ2 formed by the optical axis 141A of the first retardation film 141 and the optical axis 120A of the polarizing film 120 can be 135°±10°. In this case, when a user views the image of the display device 100 while wearing polarized sunglasses, the rainbow effect is not visible, resulting in excellent display quality.

[0066] The storage modulus of each of the first retardation membrane 141 and the second retardation membrane 142 can be 10. 6 Pa to 10 9Pa. The Poisson's ratio of each of the first retardation film 141 and the second retardation film 142 may be from 0.30 to 0.43. Storage modulus and Poisson's ratio are physical properties related to the folding characteristics of the first retardation film 141 and the second retardation film 142. When the storage modulus and Poisson's ratio are within the ranges mentioned above, the folding characteristics and reliability of the film are excellent, making it easy to realize the display device as a flexible display device, such as a foldable or rollable display device. The storage modulus and Poisson's ratio can be measured by the method defined in ASTM E2001-13 and at room temperature (20±5℃).

[0067] A hard coating layer 150 may be disposed on the second retardation film 142. The hard coating layer 150 is positioned on the top layer to be exposed to the outside. The hard coating layer 150 protects the display device 100 from foreign objects or scratches. Therefore, the hard coating layer 150 may be formed of a material with high surface hardness. For example, the hard coating layer 150 may be formed of a polyurethane-based resin or an acrylic resin, but is not limited thereto. The hard coating layer 150 may be formed by directly coating a hard coating composition, and as another example, it may be formed by bonding a separate hard coating film to the second retardation film 142 using an adhesive.

[0068] In the following text, reference will be made to Figures 3 to 11 The rainbow spot improvement effect of a display device according to an exemplary embodiment of the present disclosure is described.

[0069] first, Figure 3 This shows an in-plane phase difference R with a diameter of 137.5 nm. in PET film and in-plane phase difference R with 3000nm in A graph showing the relationship between the transmittance of PET film laminates and wavelength. Figure 4 This is an illustration of someone wearing polarized sunglasses and viewing an image including those with... Figure 3 The diagram shown is what a user of a display device would see in an exemplary embodiment of a laminate with the indicated transmittance.

[0070] refer to Figure 3 A PET film with an in-plane phase difference of 137.5 nm and a PET film with an in-plane phase difference of 3000 nm are laminated together, allowing strong transmission of light with specific wavelengths in the visible spectrum. In this case, due to the large differences in transmittance for each wavelength, it can be confirmed that this causes color irregularities, color shifts, and interference colors, as shown in... Figure 4 As shown, the rainbow effect is strongly visible. Specifically, the rainbow effect is strongly visible in any direction—front, left, and right—resulting in a reduction in display quality.

[0071] Figure 5It is a graph showing the relationship between the transmittance of the SRF film and the wavelength, and Figure 6 This is an illustration of someone wearing polarized sunglasses and viewing an image including those with... Figure 5 The image shown is a diagram of the SRF film's transmittance as seen by the user of a display device. The SRF film has an in-plane phase difference R of 8000 nm. in Commercially available delay membranes. (Refer to...) Figure 5 In an SRF film with an in-plane phase difference of 8000 nm, the relationship with [the desired phase difference] was confirmed. Figure 3 Compared to the laminate with the same transmittance, more peaks with similar phase differences were observed in the visible light region, but the differences in transmittance for each wavelength remained significant. Therefore, rainbow patterns were clearly visible when viewing the display screen while wearing polarized sunglasses.

[0072] Figure 7 This illustrates an exemplary embodiment of the present disclosure, including an in-plane phase difference R having a value of 10,000 nm. in PET film and an in-plane phase difference R of 20000nm in A graph showing the relationship between the transmittance of PET film laminates and wavelength. Figure 8 This is an illustration of someone wearing polarized sunglasses and viewing an image including those with... Figure 7 A diagram showing the transmittance of a laminate according to an exemplary embodiment, as viewed by a user of a display device. (Refer to...) Figure 7 It was confirmed that a peak with an in-plane phase difference of 20,000 nm was observed between the peak of the PET film with an in-plane phase difference of 10,000 nm and an adjacent peak. Therefore, in the visible light region, peaks with similar phase differences appear within a short time, reducing the difference in transmittance for each wavelength. In this case, as... Figure 8 As shown, the rainbow pattern is confirmed to be almost invisible not only from the front but also from the lateral view.

[0073] at the same time, Figure 9 This shows an in-plane phase difference R with a value of 10000 nm. in PET film and in-plane phase difference R with 3000nm in A graph showing the relationship between the transmittance of PET film laminates and wavelength. Figure 10 It shows the effect of wearing polarized sunglasses and viewing an image including those with polarized sunglasses. Figure 9 The image shows the transmittance of the laminate as seen by the user of a display device. (Refer to...) Figure 9 When PET films with an in-plane phase difference of 10000 nm and PET films with an in-plane phase difference of 3000 nm are laminated, the difference in transmittance at some wavelengths such as 580 nm, 625 nm, and 720 nm is relatively large compared to other wavelengths. Therefore, as... Figure 10As shown, it is confirmed that the rainbow pattern is slightly visible from a frontal view, while it is strongly visible from a lateral view.

[0074] Figure 11 This shows an in-plane phase difference R with a value of 20,000 nm. in PET film and in-plane phase difference R with 3000nm in A graph showing the relationship between the transmittance of PET film laminates and wavelength. Figure 12 It shows the effect of wearing polarized sunglasses and viewing an image including those with polarized sunglasses. Figure 11 The image shows the transmittance of the laminate as seen by the user of the display device. (See also...) Figure 11 and Figure 12 It is confirmed that a PET film with an in-plane phase difference of 20,000 nm is included, so as to... Figure 9 and Figure 10 Compared to the previous film, the rainbow effect at the frontal view was further improved. However, it was confirmed that the rainbow effect remained strongly visible at the lateral view.

[0075] In other words, a first retardation film 141 with an in-plane phase difference of 10,000 nm to 15,000 nm and a second retardation film 142 with an in-plane phase difference of 20,000 nm to 23,000 nm are disposed on the polarizing film 120, thereby reducing the difference in transmittance for each wavelength in the visible light region. Therefore, the visibility of the rainbow spot can be significantly reduced.

[0076] Meanwhile, the placement order of the support film 130, the first retardation film 141, and the second retardation film 142 disposed on the polarizing film 120 can be changed in various orders. Figures 13 to 17 This is a cross-sectional view of a display device according to another exemplary embodiment of the present disclosure. Except for the placement order of the support film 130, the first retardation film 141, and the second retardation film 142, Figures 13 to 17 The display device shown in each of them is with Figure 1 The display devices shown are essentially the same.

[0077] Reference Figure 13 In another exemplary embodiment of the display device 200 according to the present disclosure, a second retardation film 142 is disposed on a support film 130, and a first retardation film 141 is disposed on the second retardation film 142. A hard coating layer 150 may be directly disposed on the first retardation film 141. Alternatively, the hard coating layer 150 may be bonded to the first retardation film 141 by an adhesive.

[0078] Reference Figure 14In another exemplary embodiment of the display device 300 according to this disclosure, a support film 130 is disposed between a first retardation film 141 and a second retardation film 142. Specifically, the first retardation film 141 is disposed on a polarizing film 120, the support film 130 is disposed on the first retardation film 141, and the second retardation film 142 is disposed on the support film 130. Adhesive layers ADH3 and ADH4 are disposed between them to bond each of the films. A hard coating layer 150 may be disposed directly on the second retardation film 142. Alternatively, the hard coating layer 150 may be bonded to the second retardation film 142 by an adhesive.

[0079] Reference Figure 15 In another exemplary embodiment of the display device 400 according to this disclosure, a support film 130 is disposed between a first retardation film 141 and a second retardation film 142. Specifically, the second retardation film 142 is disposed on a polarizing film 120, the support film 130 is disposed on the second retardation film 142, and the first retardation film 141 is disposed on the support film 130. Adhesive layers ADH3 and ADH4 are disposed between them to bond each of the films. A hard coating layer 150 may be disposed directly on the first retardation film 141. Alternatively, the hard coating layer 150 may be bonded to the first retardation film 141 by an adhesive.

[0080] Reference Figure 16 In another exemplary embodiment of the display device 500 according to this disclosure, a support film 130 is disposed above a plurality of retardation films 141 and 142. Specifically, a first retardation film 141 is disposed on a polarizing film 120, a second retardation film 142 is disposed on the first retardation film 141, and the support film 130 is disposed on the second retardation film 142. The support film 130 may be disposed on the plurality of retardation films 141 and 142, wherein the surface of the support film 130 faces away from the plurality of retardation films 141 and 142, and may also face away from the display panel 110. A hard coating layer 150 may be directly disposed on the support film 130. As another example, the hard coating layer 150 may be bonded to the support film 130 by an adhesive.

[0081] Reference Figure 17 In another exemplary embodiment of the display device 600 according to this disclosure, a support film 130 is disposed above a plurality of retardation films 141 and 142. Specifically, a second retardation film 142 is disposed on a polarizing film 120, a first retardation film 141 is disposed on the second retardation film 142, and the support film 130 is disposed on the first retardation film 141. The support film 130 may be disposed between the plurality of retardation films 141 and 142 and a hard coating layer 150. The hard coating layer 150 may be disposed directly on the support film 130. As another example, the hard coating layer 150 may be bonded to the support film 130 by an adhesive.

[0082] Figures 13 to 17 Each of the display devices shown has a similar Figure 1 The display device shown is positioned differently, namely, a first retardation film 141 with an in-plane phase difference of 10,000 nm to 15,000 nm, a second retardation film 142 with an in-plane phase difference of 20,000 nm to 23,000 nm, and a support film 130. However, the same effect can be provided. With Figure 7 and Figure 8 As described above, when the first retardation film 141 and the second retardation film 142 are laminated, the transmission peaks of the second retardation film 142 compensate for the transmittance drop in the band where the transmittance between adjacent peaks in the transmission spectrum of the first retardation film 141 decreases sharply. Therefore, in the visible light region, peaks with similar phase differences appear within a short time, reducing the difference in transmittance for each wavelength. Consequently, the rainbow pattern is invisible not only from a frontal view but also from a lateral view, resulting in excellent display quality.

[0083] Exemplary embodiments of this disclosure can also be described as follows:

[0084] According to an aspect of this disclosure, a display device includes: a display panel, a polarizing film disposed on the display panel, and a plurality of retardation films disposed on the polarizing film and having different in-plane phase differences Rin, wherein the in-plane phase difference Rin of each of the plurality of retardation films is 10000 nm or greater.

[0085] The multiple retardation films may include a first retardation film and a second retardation film. The in-plane phase difference Rin of the first retardation film may be from 10,000 nm to 15,000 nm, and the in-plane phase difference Rin of the second retardation film may be from 20,000 nm to 23,000 nm.

[0086] The optical axes of the first retardation film and the second retardation film can be arranged at 90±10°.

[0087] The optical axis of the first retardation film and the optical axis of the polarizing film can be arranged at 45±10° or 135±10°, and the optical axis of the second retardation film and the optical axis of the polarizing film can be arranged at 45±10° or 135±10°.

[0088] The optical axes of the first retardation film and the polarization film can be arranged at 45±10°, and the optical axes of the second retardation film and the polarization film can be arranged at 135±10°.

[0089] The optical axes of the first retardation film and the polarization film can be arranged at 135±10°, and the optical axes of the second retardation film and the polarization film can be arranged at 45±10°.

[0090] The thickness-direction phase difference Rth of each of the multiple retardation films can be 0.5 times or less of the in-plane phase difference Rin.

[0091] The display device may also include a support film disposed between the polarizing film and a plurality of retardation films, or disposed above the plurality of retardation films, or disposed between a first retardation film and a second retardation film.

[0092] The support film can be disposed on the polarizing film, the second retardation film can be disposed between the polarizing film and the support film, and the first retardation film can be disposed on the support film.

[0093] A support film can be disposed on a polarizing film, a first retardation film can be disposed on a support film, and a second retardation film can be disposed on a first retardation film.

[0094] The support film can be placed between the polarizing film and multiple retardation films.

[0095] The support membrane can be placed between the first retardation membrane and the second retardation membrane.

[0096] The display device may also include a support film disposed on a plurality of delay films, wherein the surface of the support film facing away from the plurality of delay films may also face away from the display panel.

[0097] The thickness of each of the multiple delay films can be from 30 μm to 120 μm.

[0098] Each of the plurality of delayed films may include at least one of polyethylene terephthalate, polyethersulfone, polycarbonate, polyimide, polypropylene, cyclic olefin polymer, cyclic olefin copolymer and polymethyl methacrylate.

[0099] The storage modulus of each of the multiple delay films can be 10. 6 Pa to 10 9 Pa, and Poisson's ratio is 0.30 to 0.43.

[0100] Although exemplary embodiments of the present disclosure have been described in detail with reference to the accompanying drawings, the present disclosure is not limited thereto and may be embodied in many different forms without departing from the technical concept of the present disclosure. Therefore, the exemplary embodiments of the present disclosure are provided for illustrative purposes only and are not intended to limit the technical concept of the present disclosure. The scope of the technical concept of the present disclosure is not limited thereto. Therefore, it should be understood that the above exemplary embodiments are illustrative in all respects and do not limit the present disclosure. The scope of protection of the present disclosure should be interpreted based on the appended claims, and all technical concepts within their equivalents should be interpreted as falling within the scope of the present disclosure.

Claims

1. A display device, comprising: Display panel; A polarizing film is disposed on the display panel; as well as a plurality of retardation films provided on the polarizing film and having different in-plane retardations R in , wherein the in-plane retardation R of each of the plurality of retardation films in is 10000 nm or more, and wherein the plurality of retardation films includes a first retardation film disposed on the polarizing film and a second retardation film disposed on the first retardation film, the in-plane phase difference R in of the first retardation film is 10000 nm to 15000 nm, and the in-plane phase difference R in of the second retardation film is 20000 nm to 23000 nm.

2. The display device according to claim 1, wherein, The optical axis of the first retardation film and the optical axis of the second retardation film are arranged at 90 ± 10°.

3. The display device according to claim 2, wherein, The optical axis of the first retardation film is arranged at 45 ± 10° or 135 ± 10° with the optical axis of the polarizing film, and the optical axis of the second retardation film is arranged at 45 ± 10° or 135 ± 10° with the optical axis of the polarizing film.

4. The display device according to claim 3, wherein, The optical axis of the first retardation film is arranged at 45 ± 10° with the optical axis of the polarizing film, and the optical axis of the second retardation film is arranged at 135 ± 10° with the optical axis of the polarizing film.

5. The display device according to claim 3, wherein, The optical axis of the first retardation film is arranged at 135 ± 10° with the optical axis of the polarizing film, and the optical axis of the second retardation film is arranged at 45 ± 10° with the optical axis of the polarizing film.

6. The display device according to claim 1, wherein, The phase difference R in the thickness direction of each of the plurality of delay films th The in-plane phase difference R in 0.5 times or less.

7. The display device according to claim 1, further comprising: A support film is disposed between the polarizing film and the plurality of retardation films, or above the plurality of retardation films, or between the first retardation film and the second retardation film.

8. The display device according to claim 7, wherein, The support film is disposed on the polarizing film, the second retardation film is disposed between the polarizing film and the support film, and the first retardation film is disposed on the support film.

9. The display device according to claim 7, wherein, The support film is disposed on the polarizing film, the first retardation film is disposed on the support film, and the second retardation film is disposed on the first retardation film.

10. The display device according to claim 7, wherein, The support film is disposed between the polarizing film and the plurality of retardation films.

11. The display device according to claim 7, wherein, The support membrane is disposed between the first delay membrane and the second delay membrane.

12. The display device according to claim 1, further comprising a support film disposed on the plurality of delay films, wherein, The surface of the support film that is opposite to the plurality of delay films is also opposite to the display panel.

13. The display device according to claim 1, wherein, Each of the plurality of delay films has a thickness of 30 μm to 120 μm.

14. The display device according to claim 1, wherein, Each of the plurality of delayed films includes at least one of polyethylene terephthalate, polyethersulfone, polycarbonate, polyimide, polypropylene, cyclic olefin polymer, cyclic olefin copolymer and polymethyl methacrylate.

15. The display device according to claim 1, wherein, The storage modulus of each of the plurality of delay films is 10. 6 Pa to 10 9 Pa, and Poisson's ratio is 0.30 to 0.43.

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