Display device including privacy protection film

Abstract

A display device according to an example embodiment of the present disclosure includes a display panel and a privacy protection film disposed above the display panel and can selectively restrict a viewing angle, the privacy protection film including a first substrate, a first electrode disposed on the first substrate, a decorative resin layer disposed on the first electrode and including a plurality of accommodation portions and implementing an external light reflection image, a second electrode disposed on the decorative resin layer, a second substrate disposed on the second electrode, and an ink accommodated in each of the plurality of accommodation portions and including a plurality of charged pigment particles having an electrode property and a solvent, and the decorative resin layer contains light interference particles.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2025-0057374, filed with the Korean Intellectual Property Office on April 30, 2025, the disclosure of which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to a privacy protection film and a display device including the privacy protection film, and more specifically, to a display device for a vehicle that includes a privacy protection film capable of achieving a wide viewing angle mode and a narrow viewing angle mode, and capable of achieving the same visibility as the interior materials of the vehicle in the narrow viewing angle mode and non-driving mode. Background Technology

[0004] With the increasing demand for personal privacy protection, various related products are being developed in various fields. Among products that guarantee personal privacy, the demand for privacy protection devices attached to various display devices such as mobile phones, tablet PCs, and monitors to block side light transmission and reduce viewing angles is also increasing year by year.

[0005] In this regard, privacy films have conventionally been used, which alternately form light-transmitting regions that transmit light and light-blocking regions that block light in specific directions. In light incident from below, light with an incident angle greater than a predetermined angle is absorbed or blocked by the repeatedly formed light-blocking regions and therefore cannot pass through the privacy film. Thus, at viewing angles equal to or greater than the predetermined angle, light transmittance is significantly reduced, thereby achieving privacy protection. However, in the case of conventional privacy films, the viewing angle cannot be restored to its current state unless the film itself is removed, making it inconvenient to remove the film when privacy is not required.

[0006] Recently, in order to solve this inconvenience, a privacy protection film has been developed that can selectively switch between wide-viewing-angle and narrow-viewing-angle modes based on an externally applied electrical signal without attaching or removing the film.

[0007] However, in conventional switchable privacy films, light is blocked in narrow viewing angle mode, resulting in only a black image being visually recognized, which presents aesthetic limitations. For example, display devices can be included in vehicles to provide various information to the driver and passengers. Display devices used in vehicles may detract from the aesthetics of the vehicle's interior. Summary of the Invention

[0008] One objective of this disclosure is to provide a privacy protection film capable of displaying various colors and images other than black and white in a narrow viewing angle mode, and a display device including the privacy protection film.

[0009] Another objective of this disclosure is to provide a display device suitable for vehicles and to achieve a privacy protection film with visibility similar to that of interior trim materials in vehicles.

[0010] The purpose of this disclosure is not limited to the above-mentioned purposes, and other purposes not mentioned above will be clearly understood by those skilled in the art through the following description.

[0011] An exemplary embodiment of the present disclosure provides a display device comprising a display panel and a privacy protection film disposed above the display panel and capable of selectively restricting the viewing angle. The privacy protection film comprises: a first substrate; a first electrode disposed on the first substrate; a decorative resin layer disposed on the first electrode and including a plurality of receiving portions and realizing an image reflected by external light; a second electrode disposed on the decorative resin layer; a second substrate disposed on the second electrode; and an ink disposed in each of the plurality of receiving portions and comprising a plurality of charged pigment particles having polarity and a solvent, wherein the decorative resin layer comprises light interference particles.

[0012] Further details of the embodiments are included in the detailed description and the accompanying drawings.

[0013] According to embodiments of this disclosure, the privacy protection film includes charged pigment particles to achieve both wide-viewing-angle and narrow-viewing-angle modes. Simultaneously, the privacy protection film includes light interference particles to achieve a reflected image visible to the user in narrow-viewing-angle mode or when the display panel is not driven.

[0014] According to embodiments of this disclosure, by adjusting the structure of the light interference particles, various adjustments can be made to the reflected image, such as color or pattern, generated due to the constructive interference of reflected light.

[0015] According to embodiments of this disclosure, in a display device for a vehicle, aesthetics can be improved by matching the interior trim materials in a non-driving vehicle.

[0016] The effects of this disclosure are not limited to those illustrated above, and many more effects are included in this disclosure. Attached Figure Description

[0017] 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: Figure 1 This is a schematic cross-sectional view of a display device including a privacy protection film according to an exemplary embodiment of the present disclosure.

[0018] Figure 2A This is a schematic cross-sectional view of a privacy screen in a display device according to an embodiment of the present disclosure, in the case of a narrow viewing angle mode.

[0019] Figure 2B This is a schematic cross-sectional view of a privacy screen in a display device according to an embodiment of the present disclosure, in the case of a wide viewing angle mode.

[0020] Figure 3A This is a schematic cross-sectional view illustrating how an image is generated by external light reflection in a display device according to an embodiment of the present disclosure when the privacy protection film is in wide viewing angle mode and the display panel is in non-driving mode.

[0021] Figure 3B This is a schematic cross-sectional view illustrating how an image is generated by external light reflection in a display device according to an embodiment of the present disclosure when the privacy protection film is in wide viewing angle mode and the display panel is in driving mode.

[0022] Figure 3C This is a schematic cross-sectional view illustrating how an image is generated by external light reflection in a display device according to an embodiment of the present disclosure when the privacy protection film is in narrow viewing angle mode and the display panel is in driving mode.

[0023] Figure 4 This is a schematic cross-sectional view of a display device including a privacy protection film according to another exemplary embodiment of the present disclosure.

[0024] Figure 5 This is a cross-sectional view illustrating a method for manufacturing a privacy protection film according to an exemplary embodiment of the present disclosure.

[0025] Figure 6 This is a schematic cross-sectional view of a display device according to yet another exemplary embodiment of the present disclosure.

[0026] Figure 7 This is a schematic cross-sectional view of a display device according to yet another exemplary embodiment of the present disclosure.

[0027] Figure 8 This is an exemplary view of a display device applied to a vehicle according to an exemplary embodiment of the present disclosure.

[0028] Figure 9 This is a table showing the evaluation results of the brightness relative to the viewing angle and the realized reflected image according to the driving mode of each of Example 1, Example 2, Comparative Example and Reference Example. Detailed Implementation

[0029] The advantages and features of this disclosure, as well as methods for implementing these advantages and features, will become clear from the exemplary embodiments described in detail below and the accompanying drawings. However, this disclosure is not limited to the exemplary embodiments disclosed herein, but will be implemented in various forms. The exemplary embodiments are provided by way of example only so that those skilled in the art can fully understand the disclosure and scope of this disclosure.

[0030] The shapes, dimensions, ratios, angles, quantities, etc., shown in the accompanying drawings used to describe exemplary embodiments of this disclosure are merely examples, and this disclosure is not limited thereto. 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 used in conjunction with the term “only.” Unless otherwise expressly stated, any reference to the singular may include the plural form.

[0031] Even if not explicitly stated, components are interpreted as including the normal error range.

[0032] When using terms such as “on,” “above,” “below,” and “next to” to describe the positional relationship between two parts, one or more parts may be located between the two parts, unless the term is used with the terms “closely” or “directly.”

[0033] When one element or layer is placed "on" another element or layer, another layer or element can be directly inserted on or between that other element.

[0034] Although the terms "first," "second," etc., are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from other components. Therefore, the first component mentioned below can be a second component under the technical concept of this disclosure.

[0035] Throughout this disclosure, the same reference numerals generally denote the same elements.

[0036] For ease of description, the dimensions and thickness of each component shown in the accompanying drawings are illustrated, and this disclosure is not limited to the dimensions and thickness of the components shown.

[0037] Features of the various embodiments of this disclosure may be combined or integrated with each other in part or in whole, and may be technically interlocked and operated in various ways, and the embodiments may be performed independently or in association with each other.

[0038] The present disclosure will be described in detail below with reference to the accompanying drawings.

[0039] Figure 1 This is a schematic cross-sectional view of a display device including a privacy protection film according to an exemplary embodiment of the present disclosure.

[0040] The display device 100 according to an exemplary embodiment of the present disclosure includes a display panel PNL and a privacy protection film PPF.

[0041] A display panel PNL is a panel in which an image is displayed, and can be an organic light-emitting display panel PNL or a liquid crystal display panel PNL, but is not limited thereto. In the following description, it will be assumed that the display panel PNL is an organic light-emitting display panel.

[0042] The display panel PNL includes a substrate (SUB), thin-film transistors (TFTs), organic light-emitting elements (ELs), and an encapsulation layer (Encap).

[0043] A substrate SUB is a substrate used to support various components of a display panel PNL and can be formed of an insulating material. For example, a substrate SUB can be a glass substrate or a plastic substrate. For example, a plastic substrate can be selected from, but is not limited to, polyimide, polyethersulfone, polyethylene terephthalate, and polycarbonate.

[0044] A buffer layer 101 may be disposed on the substrate SUB to prevent the components of the display device from deteriorating due to oxygen or moisture. The buffer layer 101 may be formed as a single layer, or, if necessary, as a multi-layer structure.

[0045] A thin-film transistor (TFT), comprising a gate (G), an active layer (ACT), a source (S), and a drain (D), is disposed on a buffer layer 101. Figure 1 For ease of description, only the driving thin-film transistor TFTs among the various thin-film transistor TFTs that may be included in the display device 100 are shown. Furthermore, in Figure 1 In this paper, a thin-film transistor (TFT) with a coplanar structure is used as an example for description, but it is not limited to this. Thin-film transistor (TFT) with an anti-interlaced structure can also be used.

[0046] For example, an active layer ACT is disposed on a buffer layer 101, and a gate insulating layer 103 for insulating the active layer ACT from the gate G is disposed on the active layer ACT. Furthermore, an interlayer insulating layer 102 for insulating the gate G, source S, and drain D is disposed on the buffer layer 101. The source S and drain D, respectively in contact with the active layer ACT, are formed on the interlayer insulating layer 102. A planarization layer 104 may be disposed on the thin-film transistor TFT. The planarization layer 104 planarizes the upper portion of the thin-film transistor TFT. The planarization layer 104 may include contact holes for electrically connecting the anode AND of the thin-film transistor TFT and the organic light-emitting element EL.

[0047] An organic light-emitting element (EL) is disposed on the planarization layer 104. The organic light-emitting element (EL) includes an anode (AND), a cathode (CAT), and an organic light-emitting layer (EML).

[0048] The anode AND is disposed on the planarization layer 104. The anode AND is a component for providing holes to the organic light-emitting layer EML and is formed of a conductive material with a high work function. The anode AND can be a transparent conductive layer formed of a transparent conductive oxide (TCO). For example, the anode AND can be formed of one or more transparent conductive oxides selected from, but not limited to, indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), tin oxide (SnO2), zinc oxide (ZnO), indium copper oxide (ICO), and aluminum:zinc oxide (Al:ZnO, AZO).

[0049] A dam 105 is disposed on the anode AND and the planarization layer 104. The dam 105 defines the light-emitting area by covering the edge of the anode AND. The dam 105 can be formed of an insulating material to insulate each anode AND from each other. Furthermore, the dam 105 can be configured as a black dam with high light absorption to prevent color mixing between adjacent organic light-emitting devices.

[0050] The cathode CAT is disposed on the anode AND. The cathode CAT can be formed of a metallic material with a low work function to smoothly provide electrons to the organic light-emitting layer EML. For example, the cathode CAT can be formed of a metallic material selected from calcium (Ca), barium (Ba), aluminum (Al), silver (Ag), and alloys including one or more of these, but is not limited thereto. The cathode CAT is not patterned, but is formed as a layer on the anode AND. When the display device 100 is driven in a top-emitting mode, the cathode CAT can be formed to have a very thin thickness to be substantially transparent.

[0051] The organic light-emitting layer (EML) is positioned between the anode (AND) and the cathode (CAT). The EML is a layer in which electrons and holes combine to emit light.

[0052] To improve the luminous efficiency of the display panel PNL, it can further include a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer. For example, the hole injection layer and the hole transport layer can be disposed between the anode (AND) and the organic light-emitting layer (EML), and the electron transport layer and the electron injection layer can be disposed between the organic light-emitting layer (EML) and the cathode (CAT). Furthermore, a hole blocking layer or an electron blocking layer can be provided to further improve the recombination efficiency of holes and electrons in the organic light-emitting layer (EML).

[0053] An encapsulation layer (Encap) is disposed on the cathode (CAT) to minimize degradation of the organic light-emitting display panel due to moisture or oxygen. The encapsulation layer planarizes the upper surface of the display panel (PNL). The encapsulation layer can have a multilayer structure with inorganic layers formed of inorganic insulating material and organic layers formed of organic material stacked on top of each other. For example, the encapsulation layer includes at least one organic layer (PCL) and at least two inorganic layers (PAS1 and PAS2), and can have a multilayer structure with alternating layers of inorganic and organic PCL, but is not limited thereto. For example, the encapsulation layer can have a three-layer structure including a first inorganic layer (PAS1), an organic layer (PCL), and a second inorganic layer (PAS2). For example, the first inorganic layer (PAS1) and the second inorganic layer (PAS2) can each be independently made of materials selected from silicon nitride (SiN). x ), silicon oxide (SiO) x The organic layer PCL can be formed from one or more of silicon nitride oxide (SiON) or aluminum oxide (Al2O3), but is not limited thereto. For example, the organic layer PCL can be formed from one or more of epoxy resin, polyimide, polyethylene and silicon carbide oxide (SiOC), but is not limited thereto.

[0054] If necessary, the touch sensor unit can be disposed on the encapsulation layer to selectively impart touch sensing functionality to the display device 100.

[0055] The following text describes a privacy protection film PPF that can protect user privacy by selectively limiting the viewing angle in a display device.

[0056] The privacy protection film (PPF) is installed on the display panel PNL.

[0057] Privacy protection film (PPF) is applied to organic light-emitting display devices or liquid crystal display devices and operates in a wide viewing angle mode. In this mode, with an electric field present, light incident from the bottom at various angles is well transmitted, allowing the image displayed on the device to be seen not only on the front surface but also on the side surfaces. Conversely, without an electric field, light incident from the bottom at an angle greater than or equal to a predetermined angle is absorbed. Therefore, privacy protection can be achieved by operating in a narrow viewing angle mode, allowing the user to view the image displayed on the device only on the front surface or within a narrow viewing angle range.

[0058] refer to Figure 1 The privacy protection film PPF includes a first substrate 110a, a first electrode 120a, a decorative resin layer 130, an ink 140, a second electrode 120b, and a second substrate 110b, wherein the decorative resin layer 130 includes a plurality of receiving portions CP.

[0059] The first substrate 110a may be formed of a transparent insulating material. For example, the first substrate 110a may be formed of an insulating polymer selected from polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), polycarbonate (PC), and polyimide (PI).

[0060] For example, the thickness of the first substrate 110a can be from 10 μm to 50 μm, but is not limited thereto.

[0061] The first electrode 120a is disposed on the first substrate 110a. The first electrode 120a may be formed of a transparent conductive material to transmit light incident from the bottom well. For example, the transparent conductive material may be at least one selected from indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), aluminum zinc oxide (AZO), etc., but is not limited thereto.

[0062] The first electrode 120a may be formed on the front surface of the first substrate 110a and may be patterned to selectively overlap with a plurality of accommodating portions CP as needed.

[0063] For example, the thickness of the first electrode 120a can be from 10 μm to 30 μm, but is not limited to this.

[0064] A decorative resin layer 130 is disposed on the first electrode 120a. The decorative resin layer 130 transmits internal light incident from the lower part of the privacy protection film PPF and realizes a reflected image through external light incident from the upper part of the privacy protection film PPF. Specifically, the decorative resin layer 130 transmits upward light emitted from the display panel PNL disposed below the privacy protection film PPF, allowing the user to recognize the image realized from the display panel PNL. On the other hand, the decorative resin layer 130 can realize a reflected image, such as color or pattern, through constructive interference of the reflected light during the process of reflecting external light incident from the upper part of the privacy protection film PPF. A detailed description of the realization of a reflected image through the decorative resin layer 130 will be described later.

[0065] The decorative resin layer 130 may include optical interference particles 135 and a base resin.

[0066] The optical interference particle 135 is a material that induces constructive interference of light at multiple interfaces and can be a plate-shaped particle with a core-shell structure. The optical interference particle 135 includes a core 135a made of a low-refractive-index material and a shell 135b surrounding the core 135a and made of a high-refractive-index material.

[0067] The core 135a is located at the center of the optical interference particle 135. The core 135a is a material that determines mechanical strength and transparency, and can be made of a low refractive index material. For example, the refractive index of the core 135a can be below 1.8 or below 1.6, but is not limited thereto.

[0068] Specifically, core 135a may include layered clay compounds, inorganic oxides, or low-refractive-index polymers. For example, the layered clay compound may be one or more selected from mica, montmorillonite, vermiculite, chlorite, montmorillonite, MMT, chlorite, soapstone, lithium soapstone, and bentonite, but is not limited thereto. The inorganic oxide may be at least one selected from silica (SiO2), alumina (Al2O3), or porous inorganic oxides, but is not limited thereto. Furthermore, the low-refractive-index polymer is a polymer with a refractive index of 1.8 or less or 1.6 or less, and may be one or more selected from polyester, polyacrylonitrile, polystyrene, nylon, polypropylene, polyvinyl alcohol, polycarbonate, polyethylene naphthalate, polyethylene terephthalate, polymethyl methacrylate, polyetheretherketone, polyphenylene terephthalate, polyphenylene sulfide, or copolymers thereof, but is not limited thereto.

[0069] The core 135a can have a plate shape in which the width and length are greater than the thickness. For example, the core 135a may have a size of less than 3 μm and the thickness to plate length ratio may be 1:2 to 1:100 or 1:5 to 1:50, but is not limited thereto.

[0070] The outer shell 135b is configured as a surface surrounding the core 135a. The outer shell 135b is made of a material that determines the intensity of reflection due to external light and the color of the decorative resin layer 130 due to reflected light, and may be made of a high refractive index material. For example, the refractive index of the outer shell 135b may be greater than that of the core 135a, and may be 0.2 or more, or 0.4 or more, greater than that of the core 135a. Specifically, the refractive index of the outer shell 135b may be 1.8 or more, or 2.0 or more, but is not limited thereto.

[0071] Specifically, the outer shell 135b may be made of inorganic oxides. For example, the outer shell 135b may be one or more selected from aluminum oxide (Al2O3), titanium oxide (TiO2), iron oxide (Fe2O3), zirconium oxide (ZrO2), cerium oxide (CeO2) and vanadium oxide (V2O5), but is not limited thereto.

[0072] The thickness of the outer shell 135b can be adjusted according to the color of the decorative resin layer 130 caused by the reflected light to be achieved. For example, the thickness of the outer shell 135b can be from 50 nm to 300 nm, but is not limited thereto.

[0073] The decorative resin layer 130 may contain light interference particles 135 in an amount ranging from 1.0 wt% to 20.0 wt% or from 2.0 wt% to 10.0 wt% relative to the entire decorative resin layer 130. When the content of light interference particles 135 is less than the above range, the enhanced interference effect of reflected light is insufficient to achieve the color of the decorative resin layer 130 through reflected light. When the content of light interference particles 135 is greater than the above range, the total transmittance of the decorative resin layer 130 will decrease, thereby reducing the brightness of the display device.

[0074] The base resin can be a transparent insulating resin capable of transmitting light incident from below. For example, the resin can include acrylic resin, specifically, an acrylic resin formed by curing a polyurethane acrylate-based compound. Acrylic resins formed from polyurethane acrylate-based compounds have the advantages of high curability, high transparency, and high adhesive properties. For example, decorative resin layer 130 may contain 80 wt% to 99 wt% of a polyurethane acrylate-based compound, but is not limited thereto.

[0075] Multiple accommodating portions CP are formed in the decorative resin layer 130. Each of the multiple accommodating portions CP is capable of absorbing ink 140 that is incident from the outside. The multiple accommodating portions CP are grooves formed in the decorative resin layer 130 and formed on the first electrode 120a in a manner facing the second electrode 120b.

[0076] Each of the plurality of receiving portions CP is configured to be spaced apart from each other at a predetermined interval along a first direction (x-axis direction) perpendicular to the thickness direction (z-axis direction) of the decorative resin layer 130.

[0077] Each of the plurality of receiving portions CP extends in a second direction (y-axis direction) perpendicular to the first direction (x-axis direction). That is, each of the plurality of receiving portions CP can extend from one corner of the first electrode 120a to another corner parallel to it, and can be formed on the first electrode 120a in a strip structure.

[0078] Each of the plurality of receiving portions CP can be configured such that its width increases from the first electrode 120a toward the second electrode 120b. That is, the width of the upper surface of each of the plurality of receiving portions CP is greater than the width of the lower surface. Although the cross-sectional shape of each of the plurality of receiving portions CP is shown in the figures as an inverted trapezoid, it is not limited thereto.

[0079] Each of the plurality of receiving portions CP can be formed to penetrate the decorative resin layer 130, but is not limited thereto. For example, each of the plurality of receiving portions CP can be formed to be spaced apart from either the first electrode 120a or the second electrode 120b. That is, only one of the upper and lower surfaces of the decorative resin layer 130 can be open, so that the decorative resin layer 130 is not penetrated.

[0080] The ink 140 is configured to be contained in each of a plurality of containment portions CP. The ink 140 can absorb light incident from the outside in the plurality of containment portions CP.

[0081] The ink 140 includes charged pigment particles 141 and a solvent 142. The charged pigment particles 141 are light-absorbing materials, and their function is to substantially absorb light incident from the outside within the ink 140. The solvent 142 uniformly disperses the charged pigment particles 141, which are the solid content, into multiple containers CP so as to prevent sedimentation by gravity. Therefore, the charged pigment particles 141 are uniformly dispersed in the solvent 142, and the ink 140 is black.

[0082] The charged pigment particles 141 are polarized and can be positively or negatively charged absorbing materials. Therefore, when a voltage is applied to the first electrode 120a and the second electrode 120b, the charged pigment particles 141, uniformly dispersed in the solvent 142, move due to the electric field formed therebetween. A detailed description will follow later.

[0083] Specifically, the charged pigment particles 141 can be light-absorbing materials whose surfaces have been modified with negatively charged functional groups. Specifically, the negatively charged pigment particles 141 can be light-absorbing materials whose surfaces have been modified with functional groups selected from carboxylic acid groups (-COO). - ), sulfonic acid group (-SO3) - ), sulfate groups (SO4) 2- ) and fluoride ions (F - Dye particles with one or more functional groups in ) are surface modified.

[0084] The charged pigment particles 141 can be black. For example, the charged pigment particles 141 may include, but are not limited to, charged carbon nanotubes (CNTs), charged carbon black, and charged electrophoretic particles. In particular, the charged carbon nanotubes have a uniform surface area and a uniform surface shape, and therefore have high charge and uniform properties. In this case, the bistable nature of the privacy protection film (PPF) is improved, the actuation characteristics are enhanced, and the actuation stability can be improved, especially at low temperatures.

[0085] The charged pigment particles 141 may be included in an amount ranging from 0.1 wt% to 5.0 wt% relative to the total content of ink 140. When the content of charged pigment particles 141 is too small, the light absorption effect will decrease, and when the content of charged pigment particles 141 is too large, the dispersibility will decrease.

[0086] Solvent 142 may be a nonpolar solvent. For example, solvent 142 includes, but is not limited to: aromatic hydrocarbons such as benzene, toluene, xylene, phenylxylene ethane, diisopropylnaphthalene, and cycloalkanes; aliphatic hydrocarbons such as hexane, dodecylbenzene, cyclohexane, kerosene, and paraffinic hydrocarbons; halogenated hydrocarbons such as chloroform, trichloroethylene, tetrachloroethylene, trifluoroethylene, tetrafluoroethylene, dichloromethane, and ethyl bromide; phosphate esters such as tricresyl phosphate, trioctyl phosphate, diphenyl octyl phosphate, and tricyclohexyl phosphate; and phthalates such as dibutyl phthalate, dioctyl phthalate, and dibutyl phthalate. Phthalate esters of cinnamate and dicyclohexyl phthalate; carboxylic acid esters such as butyl oleate, diethylene glycol dibenzoate, dioctyl sebacate, dibutyl sebacate, trioctyl trimellitate, triethyl citrate, octyl maleate, dibutyl maleate and ethyl acetate; and isopropyl biphenyl, isopentyl biphenyl, chlorinated paraffin, diisopropylnaphthalene, 1,1-xylylethane, 1,2-xylylethane, 2,4-di-tert-aminophenol and N,N-dibutyl-2-butoxy-5-tert-octylaniline.

[0087] On the other hand, ink 140 may further contain additives such as dispersants and surfactants.

[0088] In the following text, we will refer to them together. Figure 2A and Figure 2B Describe each of the narrow-view and wide-view modes in detail.

[0089] Figure 2A This is a schematic cross-sectional view of a privacy screen in a display device according to an embodiment of the present disclosure, in the case of a narrow viewing angle mode. Figure 2B This is a schematic cross-sectional view of a display device according to an embodiment of the present disclosure, showing the privacy screen in wide-viewing-angle mode. Figure 2A and Figure 2B In this diagram, some components of the display panel PNL are omitted and only briefly shown. Specifically, only the substrate SUB, organic light-emitting elements (EL), and encapsulation layer (Encap) are shown as components of the display panel PNL.

[0090] On the other hand, Figure 2A and Figure 2B In the display device shown, the display panel PNL is in a driving mode that emits light from the organic light-emitting element EL. That is, the switch of the display panel PNL is turned on to emit light from the display panel PNL and the light enters the privacy protection film PPF.

[0091] First, refer to Figure 2A The privacy protection film PPF1 operates in a narrow viewing angle mode. In this mode, when no electric field is formed between the first electrode 120a and the second electrode 120b, charged pigment particles 141 are uniformly dispersed in the solvent 142, randomly distributed in multiple containment portions CP. As the charged pigment particles 141 are randomly distributed in the multiple containment portions CP, the multiple containment portions CP absorb incident light. Therefore, light incident at an angle greater than or equal to a predetermined angle is blocked by the multiple containment portions CP.

[0092] In other words, in narrow viewing angle mode, light emitted from the display panel PNL and incident on the privacy protection film PPF1 is absorbed by charged pigment particles 141 distributed in multiple receiving portions CP, thus preventing it from escaping to the outside of the privacy protection film PPF1. For example, in the light emitted from the display panel PNL and incident on the bottom of the privacy protection film PPF1, light L1a incident at a first angle θ1 relative to the front surface (z-axis) exits to the outside of the privacy protection film PPF1, but light L1b incident at an angle greater than the first angle θ1 (e.g., at a second angle θ2) does not escape to the outside through the charged pigment particles 141 in the receiving portion CP.

[0093] Therefore, users can view different images depending on their viewing angle. (Reference) Figure 2A Within a first angle θ1, the user can visually identify the first image IMG1, which is an image displayed by the display panel PNL. However, at angles greater than the first angle θ1, the user cannot visually identify the image displayed by the display panel PNL because the light emitted from the display panel PNL does not pass through the privacy protection film PPF1 and is not emitted to the outside. In this case, at angles greater than the first angle θ1, the user can visually identify the second image IMG2, which is a reflected image realized by the decorative resin layer 130 of the privacy protection film PPF1. The second image IMG2 is an image realized by the constructive interference of reflected light and may have color or a specific pattern shape. A detailed description of the reflected image realized by the decorative resin layer 130 will be described later.

[0094] exist Figure 2A In the display device 100a shown, the privacy protection film PPF1 can operate in a narrow viewing angle mode, so that the image displayed by the display panel PNL can only be visually recognized within a predetermined angle, and the image displayed by the display panel PNL cannot be visually recognized at a viewing angle beyond the predetermined angle, thereby achieving privacy protection.

[0095] Next, refer to Figure 2BThe privacy protection film PPF2 operates in a wide viewing angle mode. In wide viewing angle mode, when an electric field is formed between the first electrode 120a and the second electrode 120b by applying a voltage, the charged pigment particles 141, randomly distributed in the multiple accommodating portions CP, move toward the electrodes by the electric field. That is, they move toward the opposite electrode according to the type of charge on the charged pigment particles 141.

[0096] For example, when the charged pigment particles 141 are negatively charged, when a positive voltage is applied to the first electrode 120a and a negative voltage is applied to the second electrode 120b, the negatively charged pigment particles 141 move toward the lower surface of the receiving portion CP, which is in contact with the first electrode 120a opposite to the second electrode. Therefore, the charged pigment particles 141 accumulate at a predetermined height above the lower surface of the receiving portion CP.

[0097] In other words, most of the area, except for the region adjacent to the lower surface of the receiving portion CP (where charged pigment particles 141 are stacked), has a very low density of charged pigment particles 141 to form a transparent layer. Therefore, light can be transmitted to the transparent area with low density of charged pigment particles 141. Thus, in wide viewing angle mode, of the light emitted from the display panel PNL and incident on the privacy protection film PPF2, light incident at a first angle θ1 relative to the front surface (z-axis) and light incident at a larger second angle θ2 can also exit to the outside. Figure 2A In contrast, only light L1b incident at an angle greater than the second angle θ2 cannot escape to the outside because of the charged pigment particles 141 in the accommodating part CP. Therefore, compared with Figure 2A Compared to the situation shown, as the angle of light emitted outside the privacy protection film PPF2 increases, Figure 2B The privacy protection film PPF2 shown can work in wide viewing angle mode.

[0098] Therefore, users can visually recognize images with a wide field of view. Specifically, refer to... Figure 2B Within the first angle θ1, the user can visually identify the first image IMG1 as an image displayed by the display panel PNL. Furthermore, even due to... Figure 2A Even in the narrow viewing angle mode, where the second angle θ2 cannot be visually recognized, the user can still visually recognize the first image IMG1 as an image displayed by the display panel PNL.

[0099] As another example, when the charged pigment particles 141 are positively charged, a negative voltage is applied to the first electrode 120a and a positive voltage is applied to the second electrode 120b, thereby achieving a voltage similar to that applied to the first electrode 120a. Figure 2B The wide-view mode will be operated in the same way, and its redundant description will be omitted.

[0100] The viewing angle can be adjusted by the width of the lower surface of the receiving part CP, the width of the upper surface, the height of the receiving part CP, and the distance between adjacent receiving parts CP.

[0101] For example, the width of the lower surface of the receiving portion CP can be 5 μm to 15 μm or 8 μm to 15 μm, the width of the upper surface of the receiving portion CP can be 25 μm to 50 μm or 25 μm to 40 μm, the height of the receiving portion CP can be 100 μm to 160 μm or 120 μm to 160 μm, and the spacing between adjacent receiving portions CP can be 30 μm to 60 μm. Within this range, a wider viewing angle can be provided in wide-viewing-angle mode without reducing brightness, and light can be emitted at a sufficiently smaller viewing angle in narrow-viewing-angle mode to achieve more effective privacy protection.

[0102] The privacy protection film PPF can contain ink 140 including charged pigment particles 141 and solvent 142 in multiple containment sections CP, and can switch between wide viewing angle mode and narrow viewing angle mode by applying voltage.

[0103] In the following text, we will refer to them together. Figures 3A to 3C The description details how the image content caused by external light reflection is achieved based on the driving mode of the display panel and the driving mode of the privacy protection film.

[0104] Figure 3A This is a schematic cross-sectional view illustrating how an image is generated by external light reflection in a display device according to an embodiment of the present disclosure when the privacy protection film is in wide viewing angle mode and the display panel is in non-driving mode.

[0105] refer to Figure 3A The display panel PNL is in a non-driving mode where no image is displayed, and the switch of the display panel PNL is turned off, so that no light is emitted from the organic light-emitting element EL. Therefore, light does not incident on the privacy protection film PPF2. The privacy protection film PPF2 is in a wide viewing angle mode, in which the charged pigment particles 141 in the accommodating portion CP move to the vicinity of the first electrode 120a to provide a wide viewing angle.

[0106] External light L2 incident on the privacy protection film is reflected from the upper part of the privacy protection film PPF2 in the decorative resin layer 130 and emitted as a first reflected light L3a and a second reflected light L3b. In this case, the first reflected light L3a and the second reflected light L3b constructively interfere with each other to produce a specific color or pattern.

[0107] More specifically, the external light L2 is reflected by multiple interfaces of the light interference particles 135 in the decorative resin layer 130 to be emitted as first reflected light L3aa and second reflected light L3ab. A portion of the external light L2 incident on the light interference particles 135 is reflected as first reflected light L3aa at a first interface between the core 135a and the upper outer shell 135b constituting the light interference particles 135, and another portion of the external light L2 is reflected as second reflected light L3ab at a second interface between the core 135a and the outer shell 135b.

[0108] In this scenario, due to the refractive index difference between the core 135a and the outer shell 135b, another portion of the external light L2 is refracted at a specific angle of refraction at the first interface between the core 135a and the upper outer shell 135b. It is then reflected at the second interface between the core 135a and the outer shell 135b and exits through the first interface as the second reflected light L3ab. Here, the first reflected light L3aa and the second reflected light L3ab have a light path difference due to the refraction caused by the refractive index difference between the core 135a and the outer shell 135b, as well as the thickness of the core 135a. They constructively interfere with each other based on the light path difference and wavelength to produce a reflected image with a specific color or pattern.

[0109] Specifically, since the display panel PNL located beneath the privacy protection film PPF is black due to its non-driving mode, the reflected image caused by the constructive interference of the first reflected light L3a and the second reflected light L3b can be clearly seen by the user. Therefore, in the non-driving mode of the display panel PNL, the user can visually identify the second image IMG2, which is a reflected image generated by the decorative resin layer 130 of the privacy protection film PPF, without any limitation on the viewing angle.

[0110] On the other hand, the color or pattern achieved by the constructive interference of reflected light can be changed according to the thickness of the core 135a and the shell 135b. For example, as the thickness of the shell 135b increases, the visually recognizable reflected color can be adjusted by changing the reflected wavelength. Specifically, in the case where the light interference particle 135 comprises a 3 μm thick core 135a made of mica and a shell 135b made of titanium oxide (TiO2), as the thickness of the titanium oxide (TiO2) increases from 50 nm to 300 nm, the reflected color can change from yellow through red and blue to green.

[0111] On the other hand, even in Figure 3AThe image shows the privacy film in wide viewing angle mode. Even in narrow viewing angle mode, external light can still undergo constructive interference through the light interference particles 135 of the decorative resin layer 130. Even in this case, because the display panel PNL is black due to its non-driving mode, the user can visually identify reflected images with color or patterns due to the constructive interference of reflected light.

[0112] Figure 3B This is a schematic cross-sectional view illustrating how an image is generated by external light reflection in a display device according to an embodiment of the present disclosure when the privacy protection film is in wide viewing angle mode and the display panel is in driving mode.

[0113] refer to Figure 3B The display panel PNL is in a driving mode for displaying images, and the switch of the display panel PNL is turned on to emit light from the organic light-emitting element EL and the light is incident on the lower part of the privacy protection film PPF2.

[0114] At this time, as Figure 3A As shown, in Figure 3B In the privacy protection film PPF2 shown, external light L2 is reflected in the decorative resin layer 130 and emitted as a first reflected light L3a and a second reflected light L3b. In this case, the first reflected light L3a and the second reflected light L3b can constructively interfere with each other to produce a specific color or pattern.

[0115] However, unlike the display panel PNL which is in non-driving mode Figure 3A When the display panel PNL is in drive mode Figure 3B In this configuration, the display panel PNL is in a driving mode for displaying an image, and light L1 emitted from the display panel PNL and incident on the privacy protection film passes through the decorative resin layer 130 between multiple receiving portions CP. In this case, since the privacy protection film PPF2 is in a wide viewing angle mode, light L1 emitted from the display panel PNL can be incident while tilted relative to the front surface (z-axis) at a predetermined angle or greater. Because the amount of light L1 emitted from the display panel PNL is significantly greater than the amount of reflected light L3a and L3b, the reflected image formed by the constructive interference of the first reflected light L3a and the second reflected light L3b caused by the external light L2 is not visually recognizable by the user, and the first image IMG1 displayed on the display panel PNL can be visually recognized.

[0116] Figure 3C This is a schematic cross-sectional view illustrating how an image is generated by external light reflection in a display device according to an embodiment of the present disclosure when the privacy protection film is in narrow viewing angle mode and the display panel is in driving mode.

[0117] refer to Figure 3C The display panel PNL is in a driving mode for displaying images, and the switch of the display panel PNL is turned on to emit light from the organic light-emitting element EL and incident on the lower part of the privacy protection film PPF1.

[0118] Unlike the display panel PNL which is in drive mode and the privacy film PPF2 which is in wide viewing angle mode, Figure 3B ,exist Figure 3C In the middle, the privacy protection film PPF1 is in a narrow viewing angle mode in which charged pigment particles 141 are dispersed in the receiving portion CP. Therefore, as referenced Figure 2A As mentioned above, in Figure 3C In the process, the viewing angle of light L1 emitted from the display panel PNL and incident on the privacy protection film PPF1 is limited by the charged pigment particles 141 dispersed in the accommodating part CP, resulting in high brightness on the front and low brightness on the side.

[0119] In this case, such as Figure 3C As shown, external light L4 incident on the privacy protection film PPF from the top can be emitted as first reflected light L5a and second reflected light L5b through light interference particles 135 contained in the decorative resin layer 130. A reflected image with color or pattern can be achieved through the constructive interference of the first reflected light L5a and the second reflected light L5b. At this time, light L1 emitted from the display panel PNL is blocked by charged pigment particles 141 dispersed in the receiving portion CP at an angle greater than the viewing angle, allowing the user to see the reflected image resulting from the constructive interference of the reflected light caused by the external light L4 incident at an angle greater than the viewing angle.

[0120] In other words, when the privacy film PPF is in narrow viewing angle mode, the reflected image achieved by the decorative resin layer 130 can be visually recognized by the user at an angle exceeding the viewing angle. Therefore, unlike conventional privacy films where black images are only visually recognized at an angle exceeding the viewing angle, in the privacy film according to the exemplary embodiments of this disclosure, a reflected image with specific colors and patterns can be visually recognized at an angle exceeding the viewing angle in narrow viewing angle mode, allowing for the addition of various aesthetic features.

[0121] Figure 4 This is a schematic cross-sectional view of a display device including a privacy protection film according to another exemplary embodiment of the present disclosure.

[0122] refer to Figure 4The display device 200 according to an exemplary embodiment of the present disclosure includes a display panel PNL and a privacy protection film PPF. In this case, the privacy protection film PPF includes a first substrate 110a, a first electrode 120a, a decorative resin layer 230, an ink 140, a second electrode 120b, and a second substrate 110b, wherein the decorative resin layer 230 includes a plurality of receiving portions CP and a plurality of transmissive portions TP. In addition to the decorative resin layer 230 in the privacy protection film PPF further including a plurality of transmissive portions TP, Figure 4 The display device shown is Figure 1 The display device 100 shown is basically the same, so redundant descriptions will be omitted.

[0123] refer to Figure 4 The privacy protection film PPF includes multiple receiving sections (CP), multiple transmission sections (TP), and multiple decorative sections (RP).

[0124] Each of the multiple transmissive portions TP is a region that transmits light from the outside, and each of the multiple transmissive portions TP is disposed between multiple receiving portions CP. Therefore, similar to the receiving portions CP, each of the multiple transmissive portions TP is arranged to be spaced apart from each other at a fixed interval in a first direction (x-axis direction) perpendicular to the thickness direction (z-axis direction) of the decorative resin layer 230. Furthermore, each of the multiple transmissive portions TP extends along a second direction (y-axis direction) perpendicular to the first direction (x-axis direction). That is, each of the multiple transmissive portions TP extends from any one corner of the first electrode 120a to another corner parallel to it, forming a strip-shaped structure on the first electrode 120a.

[0125] Each of the plurality of transmissive sections TP can be configured such that its width decreases from the first electrode 120a toward the second electrode 120b. That is, the width of the lower surface of each of the plurality of transmissive sections TP is greater than the width of its upper surface. Figure 4 The diagram shows that each of the plurality of transmission sections TP has a trapezoidal cross-sectional shape, but is not limited thereto. For example, the cross-sectional shape of each of the plurality of transmission sections TP may be an inverted trapezoidal shape similar to that of the receiving section CP.

[0126] Each of the plurality of transmissive portions TP can be formed to penetrate the decorative resin layer 230, but is not limited thereto. For example, each of the plurality of transmissive portions TP can be formed to be spaced apart from either the first electrode 120a or the second electrode 120b. That is, only one of the upper and lower surfaces of the decorative resin layer 230 can be open, so that the decorative resin layer 230 is not penetrated.

[0127] Multiple transmissive elements (TPs) can transmit light incident from the outside. For example, light emitted from the display panel (PNL) located below the privacy film (PPF) can be transmitted from the bottom to the top.

[0128] Therefore, the multiple transmissive portions TP can be formed of an air layer or a transparent resin. The transparent resin can be formed of a transparent insulating resin capable of transmitting light incident from the bottom. For example, the transparent resin can include, but is not limited to, acrylic resin.

[0129] On the other hand, each of the multiple transmissive portions TP is configured to be spaced apart from the receiving portion CP. In this case, the space between the multiple transmissive portions TP and the multiple receiving portions CP can be defined as multiple decorative portions RP.

[0130] Each of the plurality of decorative sections RP is disposed between the receiving section CP and the transmitting section TP. The plurality of decorative sections RP transmit internal light incident from the lower part of the privacy protection film PPF and reflect at least a portion of external light incident from the upper part of the privacy protection film PPF. The plurality of decorative sections RP can achieve reflective images such as colors or patterns through constructive interference of the reflected light.

[0131] Multiple decorative parts RP are made of the material constituting the decorative resin layer 230. That is, the multiple decorative parts RP contain light interference particles 135 and a base resin. The materials constituting the multiple decorative parts RP are referenced. Figure 1 The materials described are the same, so their detailed descriptions will be omitted.

[0132] In this case, the ratio of the area of ​​the plurality of receiving portions CP and the plurality of decorative portions RP to the area of ​​the plurality of transmissive portions TP on the cross section can be 1:2 to 2:1 or approximately 1:1. The plurality of receiving portions CP absorb light emitted from the display panel PNL, and the plurality of decorative portions RP have semi-transmissive properties that reflect external light while transmitting light emitted from the display panel PNL. When the ratio of the sum of the areas of the plurality of receiving portions CP and the plurality of decorative portions RP to the area of ​​the transmissive portion TP that transmits light satisfies the above-mentioned range, the display device has high brightness, and the reflected image caused by the constructive interference of the reflected light can be visually recognized.

[0133] On the other hand, the ratio of the area of ​​the multiple receiving portions CP to the area of ​​the multiple decorative portions RP on the cross section can be 1:2 to 2:1 or approximately 1:1. When the ratio of the area of ​​the multiple receiving portions CP to the area of ​​the multiple decorative portions RP satisfies the above range, the viewing angle limiting performance is excellent, and the reflected image caused by the constructive interference of reflected light can be easily realized.

[0134] Figure 4The privacy protection film PPF shown in another exemplary embodiment of this disclosure transmits light emitted from the display panel PNL to be visible to the user, while simultaneously realizing a reflected image such as color or pattern through constructive interference of reflected light caused by external light. In this case, the privacy protection film PPF can arrange multiple transmissive portions TP between multiple receiving portions CP, thereby improving the brightness of the display device.

[0135] In the following text, reference will be made to Figure 5 A method for manufacturing a privacy protection film according to another embodiment of the present disclosure is described in detail.

[0136] Figure 5 This is a cross-sectional view illustrating a method for manufacturing a privacy protection film according to an exemplary embodiment of the present disclosure.

[0137] First, such as Figure 5 As shown in stage (a), a decorative coating composition comprising a curable resin containing optical interference particles 135 is prepared. The prepared decorative coating composition is applied onto the release layer 10 and then cured to form a decorative coating 230'.

[0138] Next, as Figure 5 As shown in stage (b), a plurality of transmissive portions TP are formed on the decorative coating 230'. At this time, the process of forming the transmissive portions TP can remove a portion of the decorative coating 230' by performing a molding process or a photoresist process. In this case, the plurality of transmissive portions TP can be formed with a width that decreases from the upper surface toward the lower surface.

[0139] Next, as Figure 5 As shown in stage (c), the decorative coating 230' is rotated so that the release layer 10 is on top, inverting its upper and lower surfaces, and then the first substrate 110a and the first electrode 120a are formed on the lower surface of the decorative coating 230'.

[0140] Next, as Figure 5 As shown in stage (d), after removing the release layer 10, a plurality of receiving portions CP are formed. The process of forming the receiving portions CP can be performed by a molding process located between and spaced apart from each of the plurality of transmissive portions TP to remove a portion of the decorative coating 230'. At this time, the plurality of receiving portions CP can be formed to have a width that decreases from the upper surface of the decorative coating 230' toward the lower surface.

[0141] Next, as Figure 5 As shown in stage (e), ink 140 comprising charged pigment particles and solvent is injected into each of the plurality of containment sections CP.

[0142] Next, as Figure 5 As shown in stage (f), a privacy protection film can be manufactured by forming a second substrate 110b and a second electrode 120b on the upper surface of the decorative coating resin layer 230.

[0143] The privacy protection film PPF disclosed herein can be used in display devices.

[0144] Figure 6 This is a schematic cross-sectional view of a display device according to yet another exemplary embodiment of the present disclosure.

[0145] refer to Figure 6 The display device 300 according to an exemplary embodiment of the present disclosure includes a display panel PNL, a polarizing layer POL, a privacy protection film PPF, and a cover window CW. In addition to the display device 300 further including a polarizing layer POL and a cover window CW, Figure 6 The display device 300 shown and Figure 1 The display device 100 shown is basically the same, so redundant descriptions will be omitted.

[0146] A polarizing layer (POL) is disposed on the display panel PNL. A common problem with organic light-emitting diode (OLED) displays is that external light is reflected by the metal material used to form the cathode, which has high reflectivity, thus reducing reflective visibility and contrast. Therefore, to reduce reflections caused by external light, a polarizing layer (POL) is disposed between the display panel PNL and the cover window (CW) to absorb external light. The polarizing layer (POL) is a layer with a predetermined light transmittance level that absorbs external light and its reflected light to prevent a decrease in contrast.

[0147] The cover window (CW) protects the display device 300 from external impacts and scratches. Therefore, the cover window (CW) can be made of a transparent material with high impact and scratch resistance. Furthermore, the cover window (CW) protects the display panel (PNL) from moisture penetration from the outside.

[0148] The cover window (CW) can be implemented as a plastic-based cover to reduce the thickness and weight of the display device 300. For example, the cover window CW can be a layer made of polymers such as polyimide, polyamide-imide, polyethylene terephthalate, polymethyl methacrylate, polypropylene glycol, and polycarbonate, but is not limited to these. Furthermore, the cover window CW can have a multilayer structure with various functional layers stacked on top of each other. For example, the cover window CW may include various functional layers such as an external light reflection reduction layer, a UV blocking layer, and a hard coating.

[0149] The privacy screen protector (PPF) is positioned below the cover window (CW). The PPF can be applied to the display panel (PNL) to provide a narrow viewing angle mode and a wide viewing angle mode. In the narrow viewing angle mode, it provides an image visible to the user, induced by light emitted from the organic light-emitting layer of the display panel (PNL). In the wide viewing angle mode, it provides an image visible to others around the display panel (PNL).

[0150] The privacy protection film's PPF, narrow viewing angle mode, and wide viewing angle mode configuration, as well as the reflective image achieved through the decorative resin layer 130, are referenced above. Figure 1 , Figure 2A , Figure 2B and Figures 3A to 3C Since the content described is the same, redundant descriptions will be omitted.

[0151] Figure 7 This is a schematic cross-sectional view of a display device according to yet another exemplary embodiment of the present disclosure.

[0152] refer to Figure 7 Apart from the different positions of the privacy protection film PPF, the display device 400 according to yet another exemplary embodiment of this disclosure and Figure 6 The display device 300 shown is basically the same, so redundant descriptions will be omitted.

[0153] The privacy protection film (PPF) is positioned between the polarizing layer (POL) and the cover window (CW). The PPF can be applied to the display panel (PNL) to provide a narrow viewing angle mode and a wide viewing angle mode. In the narrow viewing angle mode, it provides an image visible to the user, induced by light emitted from the organic light-emitting layer of the display panel (PNL). In the wide viewing angle mode, it provides an image visible to others around the display panel (PNL).

[0154] In addition, since the cover window CW is set on the privacy protection film PPF, it can protect the privacy protection film PPF from the influence of the external environment or user touch input.

[0155] Figure 8 This is an exemplary view of a display device applied to a vehicle according to an exemplary embodiment of the present disclosure.

[0156] The display device 1000 according to an exemplary embodiment of the present disclosure may be disposed on at least a portion of the dashboard of a vehicle. The dashboard of the vehicle includes a configuration disposed in front of the front seats of the vehicle (e.g., the driver's seat and the front passenger seat). For example, input configurations for operating various functions inside the vehicle (e.g., air conditioning, audio system, and navigation system) may be disposed on the dashboard of the vehicle.

[0157] In the display device 1000 according to an exemplary embodiment of the present disclosure, the display device 1000 may be disposed on the dashboard of a vehicle and operate as an input unit for operating at least a portion of the various functions of the vehicle. The display device 1000 may provide various information related to the vehicle, such as driving information of the vehicle (e.g., the current speed of the vehicle, the amount of fuel remaining and the distance traveled) and information on vehicle components (e.g., the degree of damage to the vehicle's tires).

[0158] The display device 1000 can be installed across the driver's seat and the front passenger seat in the front row of the vehicle. Users of the display device 1000 can include the driver and the passenger in the front passenger seat. Both the driver and the passenger can use the display device 1000.

[0159] The display device 1000 according to an exemplary embodiment of this disclosure includes a privacy film located on the display panel PNL. Wide viewing angle mode and narrow viewing angle mode can be freely selected by the user through the privacy film. Simultaneously, the privacy film can achieve reflective images such as colors or patterns through constructive interference of reflected light during the reflection of external light incident from the front surface of the display device 1000. By using the privacy film to achieve reflective images and selectively adjusting the color or pattern of the reflected images to integrate with the vehicle's interior, aesthetics are maximized.

[0160] The effects of the present disclosure described above will be described in more detail below with reference to examples and comparative examples. However, the following examples are for illustrative purposes only, and the scope of the present disclosure is not limited to the following examples.

[0161] Figure 9 This is a table showing the brightness relative to the viewing angle and the evaluation results of the achieved image based on the driving mode of each of Example 1, Example 2, Comparative Example and Reference Example.

[0162] Example 1 is Figure 1 The privacy protection film shown, and the light interference particles 135 constituting the decorative resin layer 130, use particles comprising a core 135a made of mica with a major axis to minor axis ratio of 5:1 and a major axis length of 3 μm, and a shell 135b made of TiO2 surrounding the core 135a with a thickness of 200 nm. Multiple receptacles CP formed in the decorative resin layer 130 are formed with a lower surface width of 8 μm, an upper surface width of 24 μm, a height of 100 μm, and a gap of 100 μm, and ink 140 comprising charged carbon black and solvent 142 is injected into the receptacles CP.

[0163] Example 2 is Figure 4The privacy protection film shown, compared to Example 1, has multiple transmissive portions TP formed between multiple receiving portions CP. Each transmissive portion TP has a lower surface width of 15 μm, an upper surface width of 6 μm, and a height of 100 μm, and is formed to be spaced 6 μm apart from the receiving portions.

[0164] The comparative example is a privacy protection film with a structure that does not contain light interference particles, compared to Example 1.

[0165] The reference example is a privacy protection film with a structure that further includes a reflective photosensitive layer containing optical interference particles 135 located on the upper electrode, compared to the comparative example.

[0166] [Experimental Example 1]

[0167] To determine the driving characteristics of the privacy films manufactured according to the Comparative Example, Reference Example, Example 1, and Example 2, the luminance relative to the viewing angle over time was measured. Furthermore, an image visible from above the privacy film was captured when the display panel PNL beneath the privacy film was in non-driving mode. The luminance was measured using a SpectraDo PR-680, and the results are as follows: Figure 9 As shown in the image.

[0168] refer to Figure 9 In the comparative example, in the non-driving mode, the display panel PNL is not visually recognized and black is visually recognized. However, in Examples 1 and 2, including the decorative resin layer 130, constructive interference of reflected light occurs due to the light interference particles 135, and an image with a deep yellow hue is partially visually recognized. That is, even when the display device is not driven, a specific color or pattern can be visually recognized in the display device, and by utilizing this color or pattern, the surrounding interior decoration can be matched to enhance aesthetics.

[0169] On the other hand, in Example 2, by further forming a decorative part in the decorative resin layer 130, it was confirmed that the brightness was improved at both the front (0°) and a specific viewing angle (30°) compared to Example 1.

[0170] Exemplary embodiments of this disclosure can also be described as follows: An exemplary embodiment of the present disclosure provides a display device including a display panel and a privacy film disposed on the upper part of the display panel and selectively restricting the viewing angle. The privacy film includes: a first substrate; a first electrode disposed on the first substrate; a decorative resin layer disposed on the first electrode and including a plurality of receiving portions for realizing an image reflected by external light; a second electrode disposed on the decorative resin layer; a second substrate disposed on the second electrode; and an ink contained in each of the plurality of receiving portions and including a plurality of charged pigment particles having polarity and a solvent, wherein the decorative resin layer contains light interference particles.

[0171] Optical interference particles can be materials that cause constructive interference of reflected light at multiple interfaces due to external light.

[0172] Optical interference particles can be plate-shaped particles that include a core and a shell with a refractive index greater than that of the core.

[0173] The refractive index of the core can be below 1.6, while the refractive index of the outer shell can be above 2.0.

[0174] The core may contain at least one of mica, silicon dioxide (SiO2), and low-refractive-index polymers.

[0175] The outer shell may contain one or more of the following: aluminum oxide (Al2O3), titanium oxide (TiO2), iron oxide (Fe2O3), zirconium oxide (ZrO2), cerium oxide (CeO2), and vanadium oxide (V2O5).

[0176] The core size can be less than 3 μm, and the shell thickness can be from 50 nm to 300 nm.

[0177] The thickness of the outer shell can range from 50 nm to 300 nm.

[0178] The charged pigment particles can be positively or negatively charged carbon nanotubes, carbon black, or electrophoretic particles.

[0179] Each of the plurality of receiving portions may be formed facing the second electrode, configured to be spaced apart from each other at a predetermined interval along a first direction perpendicular to the thickness direction of the decorative resin layer, and extending along the thickness direction and a second direction perpendicular to the first direction.

[0180] The width of each of the plurality of accommodating portions may increase as it approaches the second electrode from the first electrode.

[0181] The decorative resin layer may further include multiple transmissive portions located between multiple receiving portions.

[0182] The width of each of the multiple transmission sections can decrease as it approaches the second electrode from the first electrode.

[0183] The decorative resin layer may include a plurality of decorative portions located between the receiving portion and the transmitting portion and provided with light interference particles. The ratio of the area of ​​the plurality of receiving portions and the plurality of decorative portions to the area of ​​the plurality of transmitting portions on the cross section may be 1:2 to 2:1.

[0184] The ratio of the area of ​​multiple receiving parts to the area of ​​multiple decorative parts on the cross section can be from 1:2 to 2:1.

[0185] Each of the multiple transmissive sections can be formed from transparent resin or an air layer.

[0186] The display device may further include a polarizing layer disposed on the display panel and a cover window disposed on the polarizing layer. A privacy protection film may be disposed between the polarizing layer and the cover window or below the cover window.

[0187] While 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 various 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 embodiments are illustrative in all embodiments 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 the equivalent scope thereof should be understood to fall within the scope of the present disclosure.

Claims

1. A display device, comprising: Display panel; as well as A privacy protection film is disposed on the upper part of the display panel and can selectively restrict the viewing angle. The privacy protection film includes: First substrate; A first electrode is disposed on the first substrate; A decorative resin layer is disposed on the first electrode, including multiple receiving portions, and realizes an external light reflection image; The second electrode is disposed on the decorative resin layer; A second substrate, the second substrate being disposed on the second electrode; and The ink, contained in each of the plurality of receptacles, comprises a plurality of charged pigment particles having polarity and a solvent. The decorative resin layer includes optical interference particles.

2. The display device according to claim 1, wherein, The optical interference particles are materials that cause constructive interference of reflected light generated by external light at multiple interfaces.

3. The display device according to claim 1, wherein, The optical interference particle is a plate-shaped particle comprising a core and a shell with a refractive index greater than that of the core.

4. The display device according to claim 3, wherein, The refractive index of the core is below 1.6, and The refractive index of the outer shell is greater than 2.

0.

5. The display device according to claim 3, wherein, The core comprises at least one of mica, silicon dioxide (SiO2), and a low-refractive-index polymer.

6. The display device according to claim 3, wherein, The outer shell contains at least one selected from aluminum oxide (Al2O3), titanium oxide (TiO2), iron oxide (Fe2O3), zirconium oxide (ZrO2), cerium oxide (CeO2), and vanadium oxide (V2O5).

7. The display device according to claim 3, wherein, The kernel size is less than 3 μm, and The thickness of the outer shell is 50 nm to 300 nm.

8. The display device according to claim 1, wherein, The charged pigment particles are positively or negatively charged carbon nanotubes, carbon black, or electrophoretic particles.

9. The display device according to claim 1, wherein, Each of the plurality of accommodating portions is formed facing the second electrode, and the plurality of accommodating portions are configured to be spaced apart from each other at a predetermined interval along a first direction perpendicular to the thickness direction of the decorative resin layer, and extend along the thickness direction and a second direction perpendicular to the first direction.

10. The display device according to claim 9, wherein, The width of each of the plurality of accommodating portions increases as it approaches the second electrode from the first electrode.

11. The display device according to claim 1, wherein, The decorative resin layer also includes a plurality of transmissive portions located between the plurality of receiving portions.

12. The display device according to claim 11, wherein, The width of each of the plurality of transmissive sections decreases from the first electrode toward the second electrode.

13. The display device according to claim 11, wherein, The decorative resin layer includes a plurality of decorative portions located between the receiving portion and the transmissive portion and provided with the light interference particles, and The ratio of the sum of the areas of the plurality of receiving portions and the plurality of decorative portions on the cross section along the thickness direction to the area of ​​the plurality of transmissive portions is 1:2 to 2:

1.

14. The display device according to claim 13, wherein, The ratio of the area of ​​the plurality of receiving portions to the area of ​​the plurality of decorative portions on the cross section along the thickness direction is 1:2 to 2:

1.

15. The display device according to claim 11, wherein, Each of the plurality of transmissive sections is formed of transparent resin or an air layer.

16. The display device according to claim 1, further comprising: A polarizing layer is disposed on the display panel; as well as A cover window, wherein the cover window is disposed on the polarizing layer. The privacy protection film is disposed between the polarizing layer and the cover window or below the cover window.

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