KR102715321B1 - Display device - Google Patents

Abstract

A display device is provided. The display device includes a substrate, a thin film transistor layer disposed on the substrate, a light emitting element layer disposed on the thin film transistor layer, and a thin film encapsulation layer disposed on the light emitting element layer, wherein the thin film encapsulation layer includes an encapsulating organic film including an acrylic copolymer containing an aromatic ring, and the acrylic copolymer is formed by copolymerizing a first monomer having a hydrocarbon group having 1 to 30 carbon atoms and a second monomer including at least one aromatic ring compound and having a hydrocarbon group having 1 to 30 carbon atoms.

Description

Display device {Display device}

The present invention relates to a display device. More specifically, it relates to a display device including a thin film encapsulation layer having a phase difference function.

The importance of display devices is gradually increasing along with the development of multimedia. In response, various display devices such as liquid crystal display devices (LCDs) and organic light emitting diode display devices (OLEDs) are being developed.

Among display devices, an organic light-emitting display device includes an organic light-emitting element, which is a self-luminous element. The organic light-emitting element may include two opposing electrodes and an organic light-emitting layer interposed therebetween. Electrons and holes provided from the two electrodes recombine in the light-emitting layer to generate excitons, and the generated excitons change from an excited state to a ground state, thereby emitting light.

These organic light-emitting display devices are attracting attention as next-generation display devices because they do not require a separate light source, so they consume less power and can be configured as lightweight and thin, and they also have high-quality characteristics such as a wide viewing angle, high brightness and contrast, and fast response speed.

The problem to be solved by the present invention is to provide an organic light emitting display device including a thin film encapsulation layer having a phase difference function.

The problem that the present invention seeks to solve is to provide a display device with reduced side external light reflection.

The tasks of the present invention are not limited to the tasks mentioned above, and other technical tasks not mentioned will be clearly understood by those skilled in the art from the description below.

According to one embodiment of the present invention for solving the above-described problem, a display device includes a substrate, a thin film transistor layer disposed on the substrate, a light emitting element layer disposed on the thin film transistor layer, and a thin film encapsulation layer disposed on the light emitting element layer, wherein the thin film encapsulation layer includes an encapsulating organic film including an acrylic copolymer containing an aromatic ring, and the acrylic copolymer is formed by copolymerizing a first monomer having a hydrocarbon group having 1 to 30 carbon atoms and a second monomer including at least one aromatic ring compound and having a hydrocarbon group having 1 to 30 carbon atoms.

The above thin film encapsulation layer can satisfy the following equation 1.

[Formula 1]

nz≠nx=ny

(Here, 'nx' is the refractive index of the thin film encapsulation layer in the X-axis direction, which is the longitudinal axis of the thin film encapsulation layer, 'ny' is the refractive index of the thin film encapsulation layer in the Y-axis direction, which is the width direction axis of the thin film encapsulation layer perpendicular to the X-axis, and 'nz' is the refractive index of the thin film encapsulation layer in the Z-axis direction, which is the thickness direction axis of the thin film encapsulation layer perpendicular to the X-axis and the Y-axis.)

The above thin film encapsulation layer may be a +C plate satisfying the following equation 2.

[Formula 2]

nz>nx=ny

The thickness direction phase difference value (Rth) of the above thin film encapsulation layer can have a range of -275 nm to 0 nm based on a wavelength of 550 nm.

The thickness direction phase difference value (Rth) of the above thin film encapsulation layer can have a range of -80 nm to -20 nm based on a wavelength of 550 nm.

The optical member may further include an optical member disposed on the thin film encapsulation layer, and the optical member may include a phase difference film of a +A plate disposed on the thin film encapsulation layer.

The above phase difference film may include at least one of a quarter wave plate (λ/4 plate) or a half wave plate (λ/2 plate).

The above thin film encapsulation layer may further include a first encapsulation inorganic film disposed between the encapsulation organic film and the light emitting element layer, and a second encapsulation inorganic film disposed on the encapsulation organic film.

It may further include a touch sensor layer disposed between the second bag inorganic membrane and the phase difference film.

The first monomer and the second monomer each contain at least one acrylic functional group, and the acrylic functional group may contain at least one of an acrylate group, an acrylamide group, an acrylnitile group, and a methacrylate group.

The first monomer may be an acrylic monomer containing an alkyl group or alkylene group having 10 to 20 carbon atoms, and the second monomer may be an acrylic monomer containing an alkyl group or alkylene group having 1 to 10 carbon atoms and at least one aromatic ring compound.

The first monomer may be represented by the following chemical formula 1, and the second monomer may be represented by the following chemical formula 2.

[Chemical Formula 1]

[Chemical formula 2]

The above acrylic copolymer can be formed by copolymerizing 20 to 40 parts by weight of the first monomer and 60 to 80 parts by weight of the second monomer.

The above acrylic copolymer can be formed by copolymerizing 35 parts by weight of the first monomer and 65 parts by weight of the second monomer.

According to another embodiment for solving the above problem, a display device includes a display panel, a polarizing film disposed on the display panel, and at least one +A plate retardation film disposed between the polarizing film and the display panel, wherein the display panel includes a substrate, a thin film transistor layer disposed on the substrate, a light emitting element layer disposed on the thin film transistor layer, and a thin film encapsulation layer disposed on the light emitting element layer, and the thin film encapsulation layer includes an encapsulation organic film having a thickness direction retardation value (Rth) in a range of -275 nm to 275 nm with respect to a wavelength of 550 nm.

The above-mentioned encapsulating organic film may include an acrylic copolymer formed by copolymerizing a first monomer having a hydrocarbon group having 1 to 30 carbon atoms and a second monomer having a hydrocarbon group having 1 to 30 carbon atoms, including at least one aromatic ring compound.

The first monomer may be represented by the following chemical formula 1, and the second monomer may be represented by the following chemical formula 2.

[Chemical Formula 1]

[Chemical formula 2]

The above acrylic copolymer can be formed by copolymerizing 35 parts by weight of the first monomer and 65 parts by weight of the second monomer.

The above phase difference film may include at least one of a quarter wave plate (λ/4 plate) or a half wave plate (λ/2 plate).

The above display panel further includes a touch sensor layer disposed on the thin film encapsulation layer, and a thickness direction phase difference value (Rth) of the thin film encapsulation layer can have a range of -80 nm to -20 nm based on a wavelength of 550 nm.

Specific details of other embodiments are included in the detailed description and drawings.

A display device according to one embodiment includes an organic thin film encapsulation layer having optical anisotropy by forming a plate-like matrix, and the organic thin film encapsulation layer can have a thickness-direction phase difference function. In addition, the organic thin film encapsulation layer can protect an organic light-emitting layer by blocking external moisture while having a phase difference function.

Accordingly, the display device according to one embodiment has the effect of preventing external light reflection that can be seen from the side.

The effects according to the embodiments are not limited to the contents exemplified above, and more diverse effects are included in the present specification.

FIG. 1 is a perspective view of a display device according to one embodiment.
FIG. 2 is a schematic cross-sectional view of a display device according to one embodiment.
FIG. 3 is a schematic structural diagram showing members included in a display panel according to one embodiment.
FIG. 4 is a cross-sectional view of a display panel according to one embodiment.
Fig. 5 is a cross-sectional view showing a light emitting element layer according to one embodiment.
Figure 6 is a cross-sectional view illustrating a modified example of the structure illustrated in Figure 5.
Figure 7 is a cross-sectional view illustrating another modified example of the structure illustrated in Figure 5.
Figure 8 is an enlarged view of part Q of Figure 4.
FIG. 9 is a drawing illustrating a planar structure of a polymer crystal molecule according to one embodiment.
Figure 10 is a plan view showing a crystal phase formed by polymer crystal molecules according to one embodiment.
Figure 11 is a schematic diagram showing the structure of a bag organic film according to one embodiment.
FIGS. 12 and 13 are schematic diagrams showing that light incident on a display device according to one embodiment is reflected.
Fig. 14 is a schematic cross-sectional view of a display device according to another embodiment.
Figure 15 is a schematic diagram showing that light incident on the display device of Figure 14 is reflected.
Figure 16 is a Poincare sphere showing the results of an external light reflection experiment of the display device of Figure 2.
Figure 17 is a Poincare sphere showing the results of an external light reflection experiment of the display device of Figure 14.
Figure 18 is a graph showing the luminance deviation of reflected light representing the results of an external light reflection experiment of the display device of Figure 2.
Figure 19 is a graph showing the luminance deviation of reflected light representing the results of an external light reflection experiment of the display device of Figure 14.
Fig. 20 is a graph showing the luminance deviation of reflected light representing the results of an external light reflection experiment of a display device according to one embodiment.

The advantages and features of the present invention, and the methods for achieving them, will become clear with reference to the embodiments described in detail below together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and the embodiments are provided only to make the disclosure of the present invention complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims.

When elements or layers are referred to as being "on" another element or layer, this includes both cases where the other element is directly on it or where there are other layers or elements intervening therebetween. Conversely, when an element is referred to as being "directly on" it indicates that there are no other intervening elements or layers. Like reference numerals throughout the specification refer to like elements.

Hereinafter, examples will be described with reference to the attached drawings.

FIG. 1 is a perspective view of a display device according to one embodiment.

Referring to FIG. 1, the display device (10) can be applied to various electronic devices, such as tablet PCs, smart phones, car navigation units, cameras, center information displays (CIDs) provided in cars, wristwatch-type electronic devices, PDAs (Personal Digital Assistants), PMPs (Portable Multimedia Players), small and medium-sized electronic devices such as game consoles, televisions, outdoor billboards, monitors, personal computers, and laptop computers, and medium and large-sized electronic devices such as laptop computers. However, these are presented as exemplary embodiments, and it is obvious that they can be employed in other electronic devices without departing from the concept of the present invention.

In some embodiments, the display device (10) may have a rectangular shape in plan view. The display device (10) may include two short sides extending in one direction and two long sides extending in another direction intersecting the one direction. A corner where the long side and the short side of the display device (10) in plan view meet may be a right angle, but is not limited thereto, and may have a rounded curved shape. The plan view of the display device (10) is not limited to the exemplified shapes, and may be applied in a square, circle, ellipse, or other shapes.

The display device (10) may be formed in a substantially rectangular shape in a plane. The display device (10) may be formed in a rectangular shape with vertical corners in a plane or a rectangular shape with rounded corners. The display device (10) may include four sides or edges. The display device (10) may include long sides and short sides.

The display device (10) may include one side and the other side. At least one of the one side and the other side of the display device (10) may be a display surface. In one embodiment, the display surface is located on one side of the display device (10), and no display may be performed in the direction of the other side. Although the following description focuses on such an embodiment, the display device may be a double-sided display device in which display is performed on both the one side and the other side.

The display device (10) can be divided into a display portion (DA) that displays an image or video depending on whether it is displayed on a flat surface or not, and a non-display portion (NDA) arranged around the display portion (DA).

The display unit (DA) may be arranged at the center of the display device (10). The display unit (DA) may include a plurality of pixels. The plurality of pixels may include a first pixel (PX1) that emits light of a first color (e.g., red light having a peak wavelength in a range of about 610 nm to about 650 nm), a second pixel (PX2) that emits light of a second color (e.g., green light having a peak wavelength in a range of about 510 nm to about 550 nm), and a third pixel (PX3) that emits light of a third color (e.g., blue light having a peak wavelength in a range of about 430 nm to about 470 nm). The first pixel (PX1), the second pixel (PX2), and the third pixel (PX3) may be arranged alternately along the matrix direction. Each pixel (PX1, PX2, PX3) may be arranged in various ways, such as a stripe type or a pentile type. That is, multiple pixels can be arranged alternately on the plane. For example, the pixels can be arranged in the direction of the matrix, but are not limited thereto.

The non-display area (NDA) can be arranged around the display area (DA). The non-display area (NDA) can surround the display area (DA). In one embodiment, the display area (DA) is formed in a rectangular shape, and the non-display area (NDA) can be arranged around the four sides of the display area (DA), but is not limited thereto. A black matrix can be arranged in the non-display area (NDA) to prevent light emitted from adjacent pixels from leaking out.

FIG. 2 is a schematic cross-sectional view of a display device according to one embodiment.

Referring to FIG. 2, the display device (10) may include a display panel (100), an optical member (300), and a cover window (500).

The display panel (100) may be a light-emitting display panel including a light-emitting element. For example, the display panel (100) may be an organic light-emitting display panel using an organic light-emitting diode, an ultra-small light-emitting diode display panel using an ultra-small light-emitting diode (micro LED), and a quantum dot light-emitting display panel including a quantum dot light-emitting diode. Hereinafter, the display panel (100) will be described mainly as an organic light-emitting display panel.

FIG. 3 is a schematic structural diagram showing members included in a display panel according to one embodiment.

Referring to FIG. 3, the display panel (100) may include a substrate (SUB), a thin film transistor layer (DRL) on the substrate (SUB), a light emitting element layer (EML) on the thin film transistor layer (DRL), a thin film encapsulation layer (ENL) on the light emitting element layer (EML), and a touch sensor layer (TSL) on the thin film encapsulation layer (ENL).

The substrate (SUB) may be a flexible substrate including a flexible polymer material such as polyimide. Accordingly, the display panel (100) may be bent, folded, or rolled. In some embodiments, the substrate may include a plurality of sub-substrates overlapped in the thickness direction with a barrier layer therebetween. In this case, each sub-substrate may be a flexible substrate.

A thin film transistor layer (DRL) may be disposed on a substrate (SUB). The thin film transistor layer (DRL) may include a circuit that drives an emission device layer (EML) of a pixel. The thin film transistor layer (DRL) may include a plurality of thin film transistors.

The light emitting element layer (EML) can be arranged on top of the thin film transistor layer (DRL). The light emitting element layer (EML) can include an organic light emitting layer. The light emitting element layer (EML) can emit light with various brightness depending on the driving signal transmitted from the thin film transistor layer (DRL).

A thin film encapsulation layer (ENL) may be arranged on the light emitting element layer (EML). The thin film encapsulation layer (ENL) may include an inorganic film or a laminated film of an inorganic film and an organic film. According to one embodiment, the thin film encapsulation layer (ENL) blocks moisture from the outside to protect the light emitting element layer (EML) which is vulnerable to moisture, and at the same time, has a phase difference function to prevent external light reflection by the thin film transistor layer (DRL).

The touch sensor layer (TSL) may be arranged on the thin film encapsulation layer (ENL). The touch sensor layer (TSL) is a layer that recognizes a touch input and may perform the function of a touch member. The touch sensor layer (TSL) may include a plurality of sensing areas and sensing electrodes. In the drawing, the touch sensor layer (TSL) is illustrated as being directly formed on the thin film encapsulation layer (ENL) and included in the display panel (100), but is not limited thereto. In some cases, the touch sensor layer (TSL) may be formed as a separate touch member and may be arranged in a state of being attached to the display panel (100). A specific description of the structure of the display panel (100) and the thin film encapsulation layer (ENL) will be described later with reference to other drawings.

Referring again to FIG. 2, the optical member (300) may be placed on the display panel (100). The optical member (300) may polarize passing light and may play a role in reducing external light reflection. According to one embodiment, the optical member (300) includes a polarizing film (310) and at least one phase difference film (330), and may prevent visibility degradation due to external light reflection.

The polarizing film (310) may include a polyvinyl alcohol film. The polarizing film (310) may be stretched in one direction. The stretching direction of the polarizing film (310) may be an absorption axis, and a direction perpendicular thereto may be a transmission axis. The polarizing film (310) includes a polarizer, which may be a functional element capable of extracting light vibrating in a specific direction from incident light vibrating in various directions. As the polarizer, a polyvinyl alcohol-based linear polarizer manufactured by uniaxially stretching a polyvinyl alcohol (PVA)-based film on which a dichroic dye or iodine is adsorbed and oriented may be used.

In an exemplary embodiment, the phase difference film (330) may be a +A plate layer including at least one of a λ/2 plate (half-wave plate) and a λ/4 plate (quarter-wave plate). Accordingly, the phase difference film (330) may have a thickness-wise phase difference value (Rth) close to 0, and an in-plane phase difference value (R ₀ ) may have a positive value. When the phase difference film (330) is a λ/4 plate (quarter-wave plate), a phase difference of 1/4 wavelength of incident light may be generated, and incident linearly polarized light may be changed into circularly polarized light by using the +A plate. In particular, incident light (Lo, illustrated in FIG. 12) that is vertically incident on the phase difference film (330) may be linearly polarized by passing through the polarizing film (310), and may be changed into circularly polarized light by passing through the phase difference film (330), thereby being blocked from being reflected to the outside. A more detailed description of the polarizing film (310) and the phase difference film (330) will be provided later.

Meanwhile, although not shown in the drawing, the polarizing film (310) and the phase difference film (330) of the optical member (300) may further include a protective substrate arranged above and below them to protect them. The protective substrate may be made of a cellulose resin such as triacetyl cellulose, a polyester resin, or the like, but is not limited thereto.

The cover window (500) may be placed on the optical member (300) to cover the upper surface of the display panel (100). Accordingly, the cover window (500) may have the function of protecting the upper surface of the display panel (100). The cover window (500) may be made of a transparent material. The cover window (500) may be made of, for example, glass or plastic.

When the cover window (500) includes glass, the glass may be ultra-thin glass (UTG) or thin film glass. When the glass is made of an ultra-thin film or thin film, it may have flexible properties such that it can be bent, folded, or rolled. The thickness of the glass may be, for example, in a range of 10 ㎛ to 300 ㎛, and specifically, glass having a thickness of 30 ㎛ to 80 ㎛ or about 50 ㎛ may be applied. The glass of the cover window (500) may include soda lime glass, alkali aluminosilicate glass, borosilicate glass, or lithium alumina silicate glass. The glass of the cover window (500) may include chemically strengthened or thermally strengthened glass to have high strength. Chemical strengthening may be performed through an ion exchange treatment process in an alkaline salt. The ion exchange treatment process may be performed twice or more.

If the cover window (500) includes plastic, it may be more advantageous in exhibiting flexible characteristics such as folding. Examples of plastics applicable to the cover window (500) include, but are not limited to, polyimide, polyacrylate, polymethylmethacrylate (PMMA), polycarbonate (PC), polyethylenenaphthalate (PEN), polyvinylidene chloride, polyvinylidene difluoride (PVDF), polystyrene, ethylene vinylalcohol copolymer, polyethersulphone (PES), polyetherimide (PEI), polyphenylene sulfide (PPS), polyallylate, triacetyl cellulose (TAC), cellulose acetate propionate (CAP), etc. The plastic cover window (500) may be formed by including one or more of the plastic materials listed above.

A cover window protective layer may be arranged in front of the cover window (500). The cover window protective layer may perform at least one of the functions of preventing scattering, absorbing shock, preventing impressions, preventing fingerprints, and preventing glare of the cover window (500). The cover window protective layer may be formed by including a transparent polymer film. The transparent polymer film may include at least one of PET (PolyEthylene Terephthalate), PEN (PolyEthylene Naphthalate), PES (Polyether Sulfone), PI (PolyImide), PAR (PolyARylate), PC (PolyCarbonate), PMMA (PolyMethyl MethAcrylate), or COC (CycloOlefin Copolymer) resin.

Although not shown in the drawing, the display panel (100), the optical member (300), and the cover window (500) of the display device (10) may be mutually coupled through a plurality of coupling members. Among the coupling members, all coupling members disposed on one side of the display panel (100), i.e., the upper surface on which the cover window (500) is disposed, may be optically transparent. The coupling members may be an optically cleared adhesive film (OCA) or an optically cleared resin (OCR).

Below, the structure of the display panel (100) will be described in detail with reference to other drawings.

FIG. 4 is a cross-sectional view of a display panel according to one embodiment.

Referring to FIGS. 3 and 4, a display panel (100) according to one embodiment may include a substrate (SUB) 110, a thin film transistor layer (DRL), a light emitting element layer (EML), a thin film encapsulation layer (ENL), and a touch sensor layer (TSL). The light emitting area of the display panel (100) refers to an area where the light emitting element layer (EML) is formed and displays an image, and the non-light emitting area refers to a surrounding area of the light emitting area.

The substrate (110) may be a rigid substrate or a flexible substrate capable of bending, folding, rolling, etc. The substrate (110) may be made of an insulating material such as glass, quartz, or polymer resin. Examples of polymeric materials may include polyethersulphone (PES), polyacrylate (PA), polyarylate (PAR), polyetherimide (PEI), polyethylenenapthalate (PEN), polyethyleneterepthalate (PET), polyphenylenesulfide (PPS), polyallylate, polyimide (PI), polycarbonate (PC), cellulosetriacetate (CAT), cellulose acetate propionate (CAP), or a combination thereof. The substrate (110) may also include a metallic material.

A thin film transistor layer (DRL) is disposed on a substrate (110, SUB). The thin film transistor layer (DRL) includes a buffer film (115), thin film transistors (120), a gate insulating film (130), an interlayer insulating film (140), a protective film (150), and a planarizing film (160).

The buffer film (115) may be disposed on the substrate (110). The buffer film (115) may be formed on the substrate (110) to protect the thin film transistors (120) and light-emitting elements from moisture penetrating through the substrate (110) that is vulnerable to moisture permeation. The buffer film (115) may be formed of a plurality of inorganic films that are alternately laminated. For example, the buffer film (115) may be formed as a multi-film in which one or more inorganic films of a silicon oxide film (SiOx), a silicon nitride film (SiNx), and SiON are alternately laminated. However, the present invention is not limited thereto, and the buffer film (115) may be omitted. In addition, a light-shielding layer formed to overlap with the thin film transistors (120) described below may be further disposed between the buffer film (115) and the substrate (110).

Thin film transistors (120) are arranged on a buffer film (115). Each of the thin film transistors (120) includes an active layer (121), a gate electrode (126), a source electrode (123), and a drain electrode (124). In FIG. 4, the thin film transistor (120) is exemplified as being formed in a top gate manner in which the gate electrode (126) is positioned above the active layer (121), but is not limited thereto. The thin film transistors (120) may be formed in a bottom gate manner in which the gate electrode (126) is positioned below the active layer (121), or in a double gate manner in which the gate electrode (126) is positioned both above and below the active layer (121).

The active layer (121) is arranged on the buffer film (115). The active layer (121) may be formed of a silicon-based semiconductor material or an oxide-based semiconductor material. As described above, a light-shielding layer may be further arranged between the buffer film (115) and the substrate (110), and the light-shielding layer may be arranged to overlap the active layer (121). The light-shielding layer may block external light incident on the active layer (121).

A gate insulating film (130) may be placed on the active layer (121). The gate insulating film (130) may be formed of an inorganic film, for example, a silicon oxide film (SiOx), a silicon nitride film (SiNx), or a multi-film thereof.

The gate electrode (126) may be arranged on the gate insulating film (130) to form a gate line. The gate electrode (126) and the gate line may be formed as a single layer or multiple layers made of one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof.

An interlayer insulating film (140) may be placed on the gate electrode (126) and the gate line. The interlayer insulating film (140) may be formed of an inorganic film, for example, a silicon oxide film (SiOx), a silicon nitride film (SiNx), or a multi-film thereof.

The source electrode (123), the drain electrode (124), and the data line may be arranged on the interlayer insulating film (140). Each of the source electrode (123) and the drain electrode (124) may be connected to the active layer (121) through a contact hole penetrating the gate insulating film (130) and the interlayer insulating film (140). The source electrode (123), the drain electrode (124), and the data line may be formed as a single layer or multiple layers made of one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof.

The protective film (150) is arranged on the source electrode (123), the drain electrode (124), and the data line, and can perform the function of insulating the thin film transistor (120). The protective film (150) can be formed of an inorganic film, for example, a silicon oxide film (SiOx), a silicon nitride film (SiNx), or a multi-film thereof.

The planarization film (160) is disposed on the protective film (150) and can perform the function of planarizing the step caused by the thin film transistor (120). The planarization film (160) can be formed of an organic film such as an acrylic resin, an epoxy resin, a phenolic resin, a polyamide resin, or a polyimide resin.

An emission layer (EML) may be disposed on a thin film transistor layer (DRL). The emission layer (EML) may include emission elements and a pixel defining film (195).

The light-emitting elements and pixel defining film (195) may be arranged on the planarization film (160). The light-emitting element may be an organic light-emitting element (OLED), in which case the light-emitting element may include an anode electrode (191), light-emitting layers (192), and a cathode electrode (193).

The anode electrode (191) can be formed on the planarization film (160). The anode electrode (191) can be connected to the drain electrode (124) of the thin film transistor (120) through a contact hole penetrating the protective film (150) and the planarization film (160).

The pixel defining film (195) may be formed to cover the edge of the anode electrode (191) on the planarizing film (160) to define pixels. That is, the pixel defining film (195) serves as a pixel defining film that defines pixels. Each pixel represents a region in which an anode electrode (191), a light-emitting layer (192), and a cathode electrode (193) are sequentially laminated, and holes from the anode electrode (191) and electrons from the cathode electrode (193) are combined with each other in the light-emitting layer (192) to emit light. The anode electrode (191) of the light-emitting element layer (EML) may be respectively arranged within each pixel defined by the pixel defining film (195).

Light-emitting layers (192) are formed on the anode electrode (191) and the pixel defining film (195). The light-emitting layer (192) may be an organic light-emitting layer. The light-emitting layer (192) may emit one of red light, green light, and blue light. Alternatively, the light-emitting layer (192) may be a white light-emitting layer that emits white light, and in this case, the light-emitting layer may have a stacked form of a red light-emitting layer, a green light-emitting layer, and a blue light-emitting layer, and may be a common layer commonly formed in pixels. In this case, the display panel (100) may further include separate color filters for displaying red, green, and blue.

The light emitting layer (192) may include a hole transporting layer, a light emitting layer, and an electron transporting layer. In addition, the light emitting layer (192) may be formed in a tandem structure of two or more stacks, and in this case, a charge generation layer may be formed between the stacks.

The cathode electrode (193) is formed on the light-emitting layer (192). The cathode electrode (193) may be formed to cover the light-emitting layer (192). The cathode electrode (193) may be a common layer formed commonly in the pixels. That is, the cathode electrode (193) may be arranged on the whole surface regardless of the light-emitting layer (192) of the light-emitting element layer (EML).

When the light emitting element layer (EML) is formed in a top emission manner in which light is emitted upward, the anode electrode (191) can be formed of a highly reflective metal material, such as a laminated structure of aluminum and titanium (Ti/Al/Ti), a laminated structure of aluminum and ITO (ITO/Al/ITO), an APC alloy, and a laminated structure of an APC alloy and ITO (ITO/APC/ITO). The APC alloy is an alloy of silver (Ag), palladium (Pd), and copper (Cu). In addition, the cathode electrode (193) can be formed of a transparent metal material (TCO, Transparent Conductive Material) such as ITO or IZO that can transmit light, or a semi-transmissive metal material (Semi-transmissive Conductive Material) such as magnesium (Mg), silver (Ag), or an alloy of magnesium (Mg) and silver (Ag). When the cathode electrode (193) is formed of a semi-transparent metal material, the light emission efficiency can be increased by a micro cavity.

When the light emitting element layer (EML) is formed in a bottom emission manner in which light is emitted in a downward direction, the anode electrode (191) may be formed of a transparent conductive material (TCO) such as ITO or IZO, or a semi-transmissive conductive material such as magnesium (Mg), silver (Ag), or an alloy of magnesium (Mg) and silver (Ag). The cathode electrode (193) may be formed of a metal material having a high reflectivity, such as a laminated structure of aluminum and titanium (Ti/Al/Ti), a laminated structure of aluminum and ITO (ITO/Al/ITO), an APC alloy, and a laminated structure of an APC alloy and ITO (ITO/APC/ITO). When the anode electrode (191) is formed of a semi-transmissive metal material, the light emission efficiency may be increased by a micro cavity.

Meanwhile, as described above, the light emitting layer (192) of the light emitting element layer (EML) can be formed with a structure of two or more stacks including a hole transporting layer, a light emitting layer, and an electron transporting layer. For detailed descriptions thereof, refer to FIGS. 5 to 7.

Fig. 5 is a cross-sectional view showing a light-emitting element layer according to one embodiment. Fig. 6 is a cross-sectional view showing a modified example of the structure shown in Fig. 5. Fig. 7 is a cross-sectional view showing another modified example of the structure shown in Fig. 5.

Referring to FIG. 5, in one embodiment, the light emitting layer (192) of the light emitting element layer (EML) may include a first hole transport layer (HTL1) positioned on the anode electrode (191), a first light emitting layer (EL11) positioned on the first hole transport layer (HTL1), and a first electron transport layer (ETL1) positioned on the first light emitting layer (EL11). In this embodiment, the light emitting layer (192) may include only one light emitting layer, for example, the first light emitting layer (EL11) as the light emitting layer, and the first light emitting layer (EL11) may be a blue light emitting layer. However, the stacked structure of the light emitting layer (192) is not limited to the structure of FIG. 5, and may be modified as illustrated in FIGS. 6 and 7.

Referring to FIG. 6, the light-emitting layer (192) may further include a first charge generation layer (CGL11) positioned on the first light-emitting layer (EL11) and a second light-emitting layer (EL12) positioned on the first charge generation layer (CGL11), and the first charge transport layer (ETL1) may be positioned on the second light-emitting layer (EL12).

The first charge generation layer (CGL11) may serve to inject charges into each adjacent light-emitting layer. The first charge generation layer (CGL11) may serve to control a charge balance between the first light-emitting layer (EL11) and the second light-emitting layer (EL12). In some embodiments, the first charge generation layer (CGL11) may include an n-type charge generation layer and a p-type charge generation layer. The p-type charge generation layer may be disposed on the n-type charge generation layer.

The second light-emitting layer (EL12) may, but is not limited to, emit blue light like the first light-emitting layer (EL11). The second light-emitting layer (EL12) may emit blue light having the same peak wavelength as or a different peak wavelength than the first light-emitting layer (EL11). In another embodiment, the first light-emitting layer (EL11) and the second light-emitting layer (EL12) may emit light of different colors. That is, the first light-emitting layer (EL11) may emit blue light and the second light-emitting layer (EL12) may emit green light.

The light-emitting layer (192) of the above-described structure includes two light-emitting layers, so that the light-emitting efficiency and lifespan can be improved compared to the structure of FIG. 5.

FIG. 7 illustrates that the light-emitting layer (192) may include three light-emitting layers (EL11, EL12, EL13) and two charge generation layers (CGL11, CGL12) interposed therebetween. As illustrated in FIG. 7, the light-emitting layer (192) may further include a first charge generation layer (CGL11) positioned on a first light-emitting layer (EL11), a second light-emitting layer (EL12) positioned on the first charge generation layer (CGL11), a second charge generation layer (CGL12) positioned on the second light-emitting layer (EL12), and a third light-emitting layer (EL13) positioned on the second charge generation layer (CGL12). The first charge transport layer (ETL1) may be positioned on the third light-emitting layer (EL13).

The third light-emitting layer (EL13) can emit blue light, similar to the first light-emitting layer (EL11) and the second light-emitting layer (EL12). In one embodiment, the first light-emitting layer (EL11), the second light-emitting layer (EL12), and the third light-emitting layer (EL13) each emit blue light, and their wavelength peaks may all be the same, or some may be different. In another embodiment, the light-emitting colors of the first light-emitting layer (EL11), the second light-emitting layer (EL12), and the third light-emitting layer (EL13) may be different. For example, each light-emitting layer may emit blue or green, or each light-emitting layer may emit red, green, and blue, thereby emitting white light overall.

Referring again to FIG. 4, the thin film encapsulation layer (ENL) may be disposed on the light emitting element layer (EML). The thin film encapsulation layer (ENL) may be disposed on the light emitting element layer (EML) to seal the substrate (110) in order to prevent impurities or moisture from penetrating from the outside. In an exemplary embodiment, the thin film encapsulation layer (ENL) may have a water vapor transmittion rate (WVTR) of 1 x 10 ^-6 g/day or less. However, the present invention is not limited thereto.

The thin film encapsulation layer (ENL) can be disposed over the entire surface regardless of each pixel of the light emitting element layer (EML). The thin film encapsulation layer (ENL) covers the light emitting element layer (EML) including the cathode electrode (193) disposed thereunder, so that the light emitting element layer (EML) can be surrounded and sealed by the thin film encapsulation layer (ENL). In addition, although not shown in the drawing, a capping layer covering the cathode electrode (193) can be further disposed between the thin film encapsulation layer (ENL) and the cathode electrode (193), in which case the thin film encapsulation layer (ENL) can directly cover the capping layer.

According to one embodiment, the thin film encapsulation layer (ENL) may include a first encapsulation inorganic film (171), an encapsulation organic film (175), and a second encapsulation inorganic film (173) sequentially laminated on a cathode electrode (193).

The first encapsulated inorganic film (171) may be arranged on one surface of the cathode electrode (193). As described above, the cathode electrode (193) may conformally reflect the step at the bottom to include an uneven shape on the surface. The first encapsulated inorganic film (171) is made of an inorganic material and may conformally reflect at least a part of the uneven shape of the cathode electrode (193) at the bottom. Accordingly, the first encapsulated inorganic film (171) may include an uneven shape on the surface like the cathode electrode (193). The first encapsulated inorganic film (171) may be arranged to cover the cathode electrode (193) to perform a function of protecting it.

The second bag inorganic film (173) can be placed on one side of the bag organic film (175).

The first bag inorganic film (171) and the second bag inorganic film (173) may be in direct contact at the edge portion. For example, when the planar shapes of the first bag inorganic film (171) and the second bag inorganic film (173) are larger than the bag organic film (175), they may be in contact with each other at the end portion. Accordingly, the bag organic film (175) may be completely sealed by the first bag inorganic film (171) and the second bag inorganic film (173). Although not shown in the drawing, the second bag inorganic film (173) may extend outwardly further than the first bag inorganic film (171), and in some cases, the first bag inorganic film (171) may extend outwardly further, or the first bag inorganic film (171) and the second bag inorganic film (173) may be formed to have the same size in plan such that the end portions are aligned with each other.

The first encapsulating inorganic film (171) and the second encapsulating inorganic film (173) may each be made of silicon nitride, aluminum nitride, zirconium nitride, titanium nitride, hafnium nitride, tantalum nitride, silicon oxide, aluminum oxide, titanium oxide, tin oxide, cerium oxide, silicon oxynitride (SiON), lithium fluoride, and the like.

The encapsulating organic film (175) can be placed between the first encapsulating inorganic film (171) and the second encapsulating inorganic film (173). The encapsulating organic film (175) can fill the uneven shape of the surface of the first encapsulating inorganic film (171) to alleviate or flatten the lower step.

The encapsulating organic film (175) is arranged to cover the first encapsulating inorganic film (171), but may be formed thicker than the first encapsulating inorganic film (171). The encapsulating organic film (175) containing an organic material is arranged to cover the first encapsulating inorganic film (171) having a step or uneven pattern formed, but may be formed so that the upper surface is substantially flat. That is, the encapsulating organic film (175) may also perform a function of compensating for the step of the first encapsulating inorganic film (171).

The bag organic film (175) may be made of acrylic resin, methacrylic resin, polyisoprene, vinyl resin, epoxy resin, urethane resin, cellulose resin, perylene resin, etc., but is not limited thereto.

In addition, the encapsulating organic film (175) according to one embodiment may include polymer crystal molecules (PM) having a network or plate-like crystal phase. The polymer crystal molecules (PM) have a crystal phase having a shape extending in a horizontal direction and may be stacked in a direction perpendicular thereto to form the encapsulating organic film (175). The polymer crystal molecules (PM) have different values in the refractive index in the direction of the plane extending in one direction and the refractive index in the thickness direction perpendicular thereto, and the encapsulating organic film (175) may have a thickness-direction phase difference. The display device (10) according to one embodiment may include polymer crystal molecules (PM) having a network or plate-like crystal phase so that the thin film encapsulating layer (ENL) may have a phase difference function.

As described above, the source electrode (123), the drain electrode (124), etc. of the thin film transistor layer (DRL) can include a material with high reflectivity to reflect external light incident from the outside toward the display surface of the display device (10). The thin film encapsulation layer (ENL) according to one embodiment has a phase difference function, thereby preventing reflection of external light incident in the direction of the display device (10). A description thereof will be given later with reference to other drawings.

The touch sensor layer (TSL) can be disposed on the thin film encapsulation layer (ENL). Since the touch sensor layer (TSL) is disposed directly on the thin film encapsulation layer (ENL), there is an advantage in that the thickness of the display device (10) can be reduced compared to a case where a separate touch panel including the touch sensor layer (TSL) is attached on the thin film encapsulation layer (ENL).

The touch sensor layer (TSL) may include touch electrodes for detecting a user's touch in a capacitive manner, and touch lines connecting the pads and the touch electrodes. For example, the touch sensor layer (TSL) may detect a user's touch in a self-capacitance manner or a mutual capacitance manner. The touch electrodes of the touch sensor layer (TSL) may be arranged in the display area (DA). The touch lines of the touch sensor layer (TSL) may be arranged in the non-display area (NDA).

Below, the thin film encapsulation layer (ENL) of the display panel (100) will be described in detail with reference to other drawings.

Figure 8 is an enlarged view of portion Q of Figure 4.

Referring to FIG. 8, the encapsulating organic film (175) of the thin film encapsulating layer (ENL) may include at least one polymer crystal molecule (PM) having a crystal phase extending in the first direction (DR1). The crystal phase of the polymer crystal molecule (PM) may have a network or plate-like structure in which the length extending in the first direction (DR1) is longer than the thickness in the second direction (DR2) perpendicular thereto. The polymer crystal molecule (PM) has a length measured in the first direction (DR1), i.e., the longitudinal direction or the width direction, which is the plane direction, which is different from the length measured in the second direction (DR2), i.e., the thickness direction. Accordingly, the polymer crystal molecule (PM) may have optical anisotropy in which the refractive index according to the plane direction and the refractive index according to the thickness direction are different from each other. The encapsulating organic film (175) formed by stacking polymer crystal molecules (PM) having such a network or plate-like crystal phase in the thickness direction may also have optical anisotropy. According to one embodiment, the encapsulating organic film (175) may have optical anisotropy in which the refractive index in the plane direction and the refractive index in the thickness direction are different by laminating the crystal phase of the polymer crystal molecule (PM) in the thickness direction. For example, the encapsulating organic film (175) may be a +C plate having a refractive index in the thickness direction greater than the refractive index in the plane direction. Accordingly, the display device (10) according to one embodiment may include the encapsulating organic film (175) of the +C plate to compensate for the insufficient thickness direction retardation value (Rth) of the retardation film (330) of the +A plate. External light incident in the lateral direction of the display device (10) is phase-delayed in the retardation film (330) of the +A plate and the encapsulating organic film (175) of the +C plate, thereby preventing external light reflection in the thin film transistor layer (DRL) of the display panel (100). A more detailed description will be given later.

Meanwhile, the polymer crystal molecule (PM) may be formed by polymerizing first and second monomers having different molecular structures. In one embodiment, the polymer crystal molecule (PM) may have one monomer form a chain of the polymer crystal molecule (PM), and another monomer may be branched from the chain to form an intermolecular interaction with another chain or an intramolecular interaction with another functional group within the chain. Accordingly, the polymer crystal molecule (PM) may form a single network or chain-like crystal phase by the intermolecular attraction formed between two different chains and the intramolecular attraction within the chain.

According to one embodiment, the polymer crystal molecule (PM) may be an acrylic copolymer containing an aromatic ring, which may be a copolymer of a first monomer (PAM1) having a hydrocarbon group having 1 to 30 carbon atoms and a second monomer (PAM2) having a hydrocarbon group having 1 to 30 carbon atoms and including at least one aromatic ring compound. Each of the first monomer (PAM1) and the second monomer (PAM2) may include at least one acrylic functional group. In an exemplary embodiment, the acrylic functional group may be, but is not limited to, an acrylate group, an acrylamide group, an acrylnitile group, a methacrylate group, or the like.

The first monomer (PAM1) can form a polymer chain included in the polymer crystal molecule (PM). That is, the first monomer (PAM1) is a monomer forming a main chain portion in a copolymer formed by copolymerization with the second monomer (PAM2), and may include a carbon chain longer than that of the second monomer (PAM2). In an exemplary embodiment, the first monomer (PAM1) may include a hydrocarbon group having 1 to 30 carbon atoms, and as an example, the first monomer (PAM1) may include an alkyl group or alkylene group having 10 to 20 carbon atoms. The first monomer (PAM1) may include at least one acrylic functional group bonded to the alkyl group or alkylene group, and preferably, the first monomer (PAM1) may include two acrylic functional groups bonded to the alkylene group having 10 to 20 carbon atoms. However, the present invention is not limited thereto.

The second monomer (PAM2) may include a functional group that forms an intermolecular force or an intramolecular force between polymer chains within the polymer crystal molecule (PM). The functional group of the second monomer (PAM2) forms a branch branched from the main chain of the first monomer (PAM1) in a copolymer formed by copolymerization with the first monomer (PAM1), and the functional group of the branch may form an intramolecular force with another functional group of the first monomer (PAM1) or the second monomer (PAM2), or an intermolecular force with another copolymer molecule. In an exemplary embodiment, the second monomer (PAM2) may include an aromatic ring compound, and the second monomer (PAM2) may include a hydrocarbon group having 1 to 30 carbon atoms, including at least one aromatic ring compound. For example, the second monomer (PAM2) may include one or more aromatic ring compounds and may include an alkyl group or alkylene group having 1 to 10 carbon atoms, and preferably, the second monomer (PAM2) may include two aromatic ring compounds bonded to an alkylene group having 1 to 10 carbon atoms, but is not limited thereto.

FIG. 9 is a drawing illustrating a planar structure of a polymer crystal molecule according to one embodiment.

FIG. 9 is a drawing schematically illustrating a network-like or plate-like crystal phase formed by a first monomer (PAM1) and a second monomer (PAM2) of a polymer crystal molecule (PM), and the polymer crystal molecule (PM) according to one embodiment may not necessarily have a structure as shown in FIG. 9. For convenience of explanation, the first monomer (PAM1) is illustrated as having a structure including two first functional groups (F1) and a hydrocarbon group (C1), and the second monomer (PAM1) is illustrated as having a structure including one second functional group (F2) and an aromatic ring compound (C2), and these can be represented by structural formulas 1 and 2, respectively.

[Structural formula 1]

F1-C1-F1

[Structural formula 2]

F2-C2

(Here, F1 is a first functional group of the first monomer (PAM1), C1 is a hydrocarbon group of the first monomer (PAM1), F2 is a second functional group of the second monomer (PAM2), and C2 is an aromatic ring compound of the second monomer (PAM2).)

As an example, when the first monomer (PAM1) has the molecular structure of the structural formula 1 and the second monomer (PAM2) has the molecular structure of the structural formula 2, the first functional group (F1) included in the first monomer (PAM1) can form a bond with the first functional group (F1) of another first monomer (PAM1) or the second functional group (F2) of the second monomer (PAM2). Here, the hydrocarbon group (C1) of the first monomer (PAM1) forms a main chain portion of the polymer crystal molecule (PM), and the aromatic ring compound (C2) of the second monomer (PAM2) can form a branch portion branched from the main chain portion.

Referring to FIG. 9, the first functional group (F1) of the first monomer (PAM1) forms a bond with the second functional group (F2) of the second monomer (PAM2), and the hydrocarbon group (C1) can form a main chain portion with the first functional group (F1) and the second functional group (F2). The first functional group (F1), the second functional group (F2), and the hydrocarbon group (C1) are included within one main chain portion, and the aromatic ring compound (C2) bonded to the second functional group (F2) can branch from the main chain portion to form a branch portion. The aromatic ring compound (C2) may form an intramolecular interaction with the first functional group (F1) of the branched main chain portion (FI1 in FIG. 9), or may form an intermolecular interaction with the first functional group (F1), the second functional group (F2) of another main chain portion, and the aromatic ring compound (C2) (FI2 in FIG. 9). The intramolecular attraction (FI1) and the intermolecular attraction (FI2) formed by the aromatic ring compound (C2) are formed between one main chain portion and another main chain portion, so that these main chain portions can form a single mesh-like or plate-like crystal phase. In addition, by a curing agent added when the first monomer (PAM1) and the second monomer (PAM2) are copolymerized, or by UV treatment after copolymerization, different main chain portions can have a crystal phase of a certain shape.

In an exemplary embodiment, the first monomer (PAM1) and the second monomer (PAM2) can be copolymerized at different content ratios to form a polymer crystal molecule (PM). The polymer crystal molecule (PM) can have a mesh or plate-like crystal phase by including a larger content of the second monomer (PAM2) than the first monomer (PAM1) to increase the intermolecular force due to the branches between the main chain portions. For example, the polymer crystal molecule (PM) can be formed by copolymerizing 20 to 40 parts by weight of the first monomer (PAM1) and 60 to 80 parts by weight of the second monomer (PAM2). Preferably, the polymer crystal molecule (PM) can be an acrylic polymer formed by copolymerizing 35 parts by weight of the first monomer (PAM1) and 65 parts by weight of the second monomer (PAM2). However, it is not limited thereto.

Meanwhile, in an exemplary embodiment, the first monomer (PAM1) may be a compound represented by the following chemical structural formula 1, and the second monomer (PAM2) may be a compound represented by the following chemical structural formula 2.

[Chemical structural formula 1]

(Here, R ₁ is a hydrocarbon group, and n1 is a natural number from 1 to 30.)

[Chemical structural formula 2]

(Here, R ₂ and R ₃ are hydrocarbon groups, and the sum of n2 and n3 is a natural number from 1 to 30.)

When the first monomer (PAM1) is a compound represented by the chemical structural formula 1, the first monomer (PAM1) may include a hydrocarbon group (C1, R ₁ ) having 1 to 30 carbon atoms, and may include two methacrylate groups connected to both ends of the hydrocarbon group as a first functional group (F1). When the second monomer (PAM2) is a compound represented by the chemical structural formula 2, the second monomer (PAM2) may include an aromatic ring compound (C2) having two benzene rings, a hydrocarbon group (R ₂ , R ₃ ) bonded therebetween, and a methacrylate group as a second functional group (F2) connected thereto.

In a non-limiting example, the first monomer (PAM1) may be a compound of formula 1 below, and the second monomer (PAM2) may be a compound of formula 2 below.

[Chemical Formula 1]

[Chemical formula 2]

The copolymer formed by copolymerizing the above chemical formulas 1 and 2 has an alkylene group of chemical formula 1 forming a main chain portion, and two benzene rings of chemical formula 2 can be branched from the main chain portion to form a branch portion.

Figure 10 is a plan view showing a crystal phase formed by polymer crystal molecules according to one embodiment.

Referring to FIG. 10, the first monomer (PAM1) of the chemical formula 1 can form a main chain portion extending in one direction, and the second monomer (PAM2) of the chemical formula 2 can have a benzene ring branched from the main chain portion to form a branch portion. Different main chain portions extend in one direction and face each other while being spaced apart from each other, and two benzene rings can be positioned between these main chain portions. The benzene ring contains a large number of pi bonds and can form an intramolecular force (FI1) with an oxygen atom (O) present in an acrylate group of the main chain portion, or an intermolecular force (FI2) with another pi bond, a benzene ring, or an acrylate group of another main chain portion. The benzene ring having a large number of electrons can form an induced dipole in a hydrocarbon group of the main chain portion, and accordingly, the polymer crystal molecule (PM) can have a mesh or plate-like crystal phase.

Meanwhile, the aromatic ring compound (C2) of the second monomer (PAM2) can be branched from the main chain portion formed by the first monomer (PAM1) in the copolymer of the polymer crystal molecule (PM) to form a branch portion. In the polymer crystal molecule (PM), the main chain portions of the first monomer (PAM1) face each other, and the aromatic ring compound (C2) branched from the main chain portion is positioned between them.

The aromatic ring compound (C2) oriented in the plane direction of the polymer crystal molecule (PM) can have a high refractive index in the plane direction because the molecular structure has a planar structure. However, these polymer crystal molecules (PM) of a mesh-like or plate-like crystal shape can be laminated at narrow intervals, and the encapsulating organic film (175) formed by laminating them in the thickness direction can have a refractive index in the thickness direction that is higher than the refractive index in the plane direction. That is, the encapsulating organic film (175) can have different values for the thickness direction retardation value (Rth) and the in-plane retardation value ( _R0 ). For example, the encapsulating organic film (175) can perform the function of a C plate having a thickness direction retardation. In order to describe this, the definition of refractive index will be described with reference to other drawings.

Figure 11 is a schematic diagram showing the structure of a bag organic film according to one embodiment.

Referring to FIG. 11, the X-axis represents the longitudinal axis of the encapsulating organic film (175), the Y-axis represents the width axis of the encapsulating organic film (175), and the Z-axis represents the thickness axis of the polymer crystal molecule (PM). These X-axis, Y-axis, and Z-axis are orthogonal to each other. At this time, if the refractive index in the X-axis direction is nx, the refractive index in the Y-axis direction is ny, and the refractive index in the Z-axis direction is nz, the refractive index relationship of the C plate can be defined by the following Equation 1.

[Formula 1]

nz≠nx=ny

The C plate can have a thickness direction refractive index nz that is different from the longitudinal and width directions, i.e., in-plane refractive indices nx and ny. At this time, when the C plate is a +C plate, the thickness direction refractive index nz can have a larger value than the longitudinal and width directions, i.e., in-plane refractive indices nx and ny, and the thickness direction retardation value (Rth) and the in-plane retardation value ( _R0 ) of the +C plate can be expressed by the following Equations 2 and 3.

[Formula 2]

Rth = d x ((nx+ny)/2-nz)

[Formula 3]

R ₀ = dx (nx-ny)

In the above equations 2 and 3, d represents the thickness of the bag organic film (175).

+C plate has a surface retardation value ( _R0 ) close to 0, and a thickness retardation value (Rth) can have a positive value. When two of the three axial refractive indices (nx, ny, nz) are the same, but the remaining one is different, it can be called a uniaxial retardation film.

Meanwhile, as described above, the phase difference film (330) of the optical member (300) may be a +A plate. The +A plate may be defined using three axial refractive indices of the phase difference film (330). For example, if the phase difference film (330) is also defined as having an X-axis refractive index of nx, a Y-axis refractive index of ny, and a Z-axis refractive index of nz, the refractive index relationship of the +A plate may be defined by the following Equation 4.

[Formula 4]

nx>ny=nz

Since the +A plate has the largest longitudinal refractive index (nx) and the other two directions, that is, the widthwise refractive index (ny) and the thicknesswise refractive index (nz), are equal, it corresponds to a uniaxial retardation film. The thicknesswise retardation value (Rth) and the in-plane retardation value (R ₀ ) of the +A plate can also be expressed by the above equations 2 and 3. Therefore, the +A plate can be a film in which the thicknesswise retardation value (Rth) is close to 0 and the in-plane retardation value (R ₀ ) has a positive value.

According to one embodiment, the encapsulating organic film (175) may be a uniaxial retardation film of a +C plate, and the retardation film (330) of the optical member (300) may be a uniaxial retardation film of a +A plate. The retardation film (330) may have a positive in-plane retardation value (R ₀ ) and a thickness-direction retardation value (Rth) close to 0. The encapsulating organic film (175) may have a in-plane retardation value (R ₀ ) close to 0 and a thickness-direction retardation value (Rth) close to 0. Accordingly, external light incident toward one surface of the display device (10) may experience a phase delay due to the retardation film (330) or the encapsulating organic film (175) depending on the incident angle. In addition, the retardation film (330) and the encapsulating organic film (175) may have reversed wavelength dispersion characteristics. The reverse wavelength dispersion has wavelength dispersion in which the phase difference value decreases as the wavelength of light becomes shorter, and can improve the quality of circular polarization implemented by phase delay. However, it is not limited thereto. The encapsulating organic film (175) and the phase difference film (330) may be -C plates and -A plates, respectively.

FIGS. 12 and 13 are schematic diagrams showing that light incident on a display device according to one embodiment is reflected.

Figure 12 shows the external light reflection when external light (L0) is incident in a direction perpendicular to the upper surface of the display device (10), and Figure 13 shows the external light reflection when external light (Lth) is incident in a direction other than perpendicular to the upper surface of the display device (10), that is, in a lateral direction.

First, referring to FIG. 12, when external light (L0) is incident in a direction perpendicular to one side of the display device (10), the light passing through the cover window (500) can be incident on the polarizing film (310) of the optical member (300). The external light (L0) vibrates in various directions and is incident on the polarizing film (310), and the polarizing film (310) can extract light vibrating in a specific direction among the external light (L0) depending on the direction of the polarizer. As illustrated in the drawing, the polarizing film (310) can linearly polarize the external light (L0) by extracting light vibrating in the X-axis direction among the external light (L0) (L0-1 of FIG. 12).

The linearly polarized external light (L0-1) can be incident on the phase difference film (330), for example, a λ/4 plate (quarter-wave plate) of the +A plate. As described above, since the +A plate has a positive in-plane phase difference value (R0) and a thickness-wise phase difference value (Rth) close to 0, light incident in a direction perpendicular to the phase difference film (330) can be delayed in phase by the in-plane phase difference value (R0) of the +A plate. Accordingly, the linearly polarized external light (L0-1) can pass through the phase difference film (330) and be circularly polarized (L0-2 in FIG. 12).

Circularly polarized external light (L0-2) may be incident on a thin film encapsulation layer (ENL), particularly, an encapsulation organic film (175) of a display panel (100). According to one embodiment, an encapsulation organic film (175) may have a +C plate in which polymer crystal molecules (PM) having a mesh-like or plate-like crystal phase are laminated. As described above, the +C plate has an in-plane retardation value (R0) close to 0 and a thickness-direction retardation value (Rth) of a negative value, so that light incident in a direction perpendicular to the encapsulation organic film (175) of the thin film encapsulation layer (ENL) may not have a phase delay according to the in-plane retardation value (R0) of the +C plate. That is, even if the circularly polarized external light (L0-2) passes through the thin film encapsulation layer (ENL), it may be incident on a thin film transistor layer (DRL) of the display panel (100) without a phase delay (L0-3 of FIG. 12).

Since the thin film transistor layer (DRL) includes a member including a material having high reflectivity, such as a source electrode (123), a drain electrode (124), etc., light incident on the thin film transistor layer (DRL) can be reflected and propagate again toward the outside of the display device (10). Here, external light (L0-3) incident on the thin film transistor layer (DRL) can be reflected with the same phase without phase delay and can be incident on the thin film encapsulation layer (ENL) (L0-4 in FIG. 12).

External light (L0-4) incident on the thin film encapsulation layer (ENL) is incident in a direction perpendicular to the lower surface of the thin film encapsulation layer (ENL), so it can pass through it with the same circular polarization without phase delay and be incident again on the retardation film (330) (L0-5 in FIG. 12). The circularly polarized external light (L0-5) incident on the retardation film (330) can be linearly polarized by the +A plate retardation film (330) having a positive in-plane retardation value (R0) and be incident on the polarizing film (310) (L0-6). The linearly polarized external light (L0-6) incident on the polarizing film (310) has a phase perpendicular to the polarizer of the polarizing film (310), and can be blocked from propagating in the polarizing film (310). Through this process, external light (L0) incident in a direction perpendicular to one side of the display device (10) can be prevented from reflecting by the polarizing film (310) of the optical member (300) and the phase difference film (330) of the +A plate λ/4 plate (quarter-wave plate).

Next, referring to FIG. 13, when external light (Lth) is incident in a direction other than perpendicular to one surface of the display device (10), for example, in a lateral direction, light passing through the cover window (500) may be incident on the polarizing film (310) of the optical member (300). As described above, the external light (Lth) may be linearly polarized by extracting light vibrating in the X-axis direction by the polarizing film (310) (Lth-1 in FIG. 13). The external light (Lth) incident in the lateral direction of the display device (10) may also be incident in the lateral direction on the optical member (300) and the display panel (100).

Linearly polarized external light (Lth-1) can be incident on the phase difference film (330) of the +A plate λ/4 plate (quarter-wave plate). Since the +A plate has a positive in-plane phase difference value (R0) and a thickness-wise phase difference value (Rth) close to 0, the external light (Lth-1) incident on the side of the phase difference film (330) may not be sufficiently phase-delayed by the thickness-wise phase difference value (Rth) of the +A plate. The external light (Lth-2) passing through the phase difference film (330) may be elliptically polarized rather than completely circularly polarized (Lth-2 in FIG. 13).

External light (Lth-2) passing through the phase difference film (330) is incident on the thin film encapsulation layer (ENL) of the display panel (100), particularly, the encapsulation organic film (175) of the +C plate having a negative thickness-direction phase difference value (Rth). Light incident in the lateral direction of the encapsulation organic film (175) undergoes a phase delay according to the thickness-direction phase difference value (Rth) of the +C plate, and the incident external light (Lth-2) passes through the encapsulation organic film (175) and becomes circularly polarized so that it can be incident on the thin film transistor layer (DRL) of the display panel (100) (Lth-3 in FIG. 13).

External light (Lth-3) incident on the thin film transistor layer (DRL) is reflected from the thin film transistor layer (DRL) and incident on the thin film encapsulation layer (ENL) (Lth-4 in FIG. 13), and depending on the thickness direction phase difference value (Rth) of the encapsulation organic film (175), the phase is delayed again and can be elliptically polarized (Lth-5 in FIG. 13).

In an exemplary embodiment, the thickness direction retardation value (Rth) of the thin film encapsulation layer (ENL) may have a range of 0 nm to -275 nm with respect to a wavelength of 550 nm. More preferably, the thickness direction retardation value (Rth) may have a range of -50 nm to -80 nm with respect to a wavelength of 550 nm. However, the present invention is not limited thereto.

The elliptically polarized external light (Lth-5) is incident laterally on the phase difference film (330), and since the phase difference film (330) of the +A plate has a thickness direction phase difference value (Rth) close to 0, the external light (Lth-5) is delayed somewhat in phase, so that the elliptically polarized external light (Lth-5) can be circularly polarized and incident on the polarizing film (310) (Lth-6 in FIG. 13). The external light (Lth-6) incident on the polarizing film (310) has a phase that is perpendicular to the polarizer of the polarizing film (310), and can be blocked from propagating in the polarizing film (310). Through this process, the external light (L0) incident laterally on one surface of the display device (10) can be prevented from reflecting by the polarizing film (310) of the optical member (300) and the encapsulating organic film (175) of the +C plate.

The encapsulating organic film (175) according to one embodiment may include a polymer crystal molecule (PM) having a mesh-like or plate-like crystal phase, and may be a C plate having a thickness-direction retardation value (Rth) that is not 0. The encapsulating organic film (175) according to one embodiment may compensate for the phase delay of external light (Lth) in the lateral direction that the retardation film (330) of the +A plate cannot completely circularly polarize. Accordingly, the display device (10) may prevent external light reflection for external light incident in the lateral direction. In addition, the encapsulating organic film (175) may have a low water vapor transmittion rate (WVTR), and thus may perform a function of protecting the light emitting element layer (EML) that is vulnerable to moisture in the external air.

Meanwhile, the optical member (300) of the display device (10) may include a larger number of phase difference films (330) than the display device (10) of FIG. 2.

Fig. 14 is a schematic cross-sectional view of a display device according to another embodiment. Fig. 15 is a schematic diagram showing that light incident on the display device of Fig. 14 is reflected.

Referring to FIG. 14, an optical member (300_1) of a display device (10_1) according to one embodiment may include a polarizing film (310_1), a first phase difference film (330_1), and a second phase difference film (350_1). The first phase difference film (330_1) and the second phase difference film (350_1) may each be the +A plates described above, and one may be a λ/2 plate (half-wave plate) and the other may be a λ/4 plate (quarter-wave plate). For example, the first phase difference film (330_1) may be a λ/4 plate (quarter-wave plate) and the second phase difference film (350_1) may be a λ/2 plate (half-wave plate).

Unlike the display device (10) of FIG. 2, the display device (10_1) of FIG. 14 may include one λ/2 plate and one λ/4 plate as the optical member (300_1), and may nevertheless prevent external light reflection of external light (L0) incident in a vertical direction of the display device (10_1) and external light (Lth) incident in a lateral direction, like the display device (10) of FIG. 2. In particular, since the first phase difference film (330_1) and the second phase difference film (350_1) are each +A plates, the external light (Lth) incident in the lateral direction may not be completely delayed in phase after passing through the polarizing film (310). However, the display device (10_1) according to one embodiment may include an encapsulating organic film (175) of a +C plate to compensate for the thickness-wise phase difference delay of the phase difference films (330_1, 350_1).

Referring to FIG. 15, external light (Lth_1) incident in the lateral direction of the display device (10_1) passes through the polarizing film (310_1) and only linearly polarized light can be extracted. However, even if the linearly polarized external light passes through the second phase difference film (350_1) and the first phase difference film (330_1), since they are +A plates with a thickness direction phase difference value (Rth) close to 0, the phase is not completely delayed and can be elliptically polarized and incident on the thin film encapsulation layer (ENL) of the display panel (100). However, in the display device (10_1) according to one embodiment, the elliptically polarized external light (Lth) is incident on the encapsulation organic film (175) of the thin film encapsulation layer (ENL) and the phase is delayed by the encapsulation organic film (175) of the +C plate and can be circularly polarized. The circularly polarized external light is reflected from the thin film transistor layer (DRL) and then passes through the encapsulating organic film (175) and the first phase difference film (330_1), whereby the phase may be delayed again.

Fig. 16 is a Poincare sphere showing the results of an external light reflection experiment of the display device of Fig. 2. Fig. 17 is a Poincare sphere showing the results of an external light reflection experiment of the display device of Fig. 14.

The surface phase difference value (R0) and the thickness direction phase difference value (Rth) were measured using the display device (10) of Fig. 2 and the display device (10_1) of Fig. 14, and the results are shown in Figs. 16 and 17. The display device (10) of Fig. 2 includes a polarizing film (310) and a +A plate λ/4 plate phase difference film (330) as an optical member (300), and includes a +C plate thin film encapsulation layer (ENL) including polymer crystal molecules (PM). The display device (10_1) of Fig. 14 includes a polarizing film (310_1) as an optical member (300_1), a first phase difference film (330_1) of a +A plate λ/4 plate, and a second phase difference film (350_1) of a +A plate λ/2 plate, and includes a +C plate thin film encapsulation layer (ENL) including polymer crystal molecules (PM).

The in-plane phase difference value (R0) was measured based on external light (φ) incident in a direction perpendicular to one side of the display device (10), and the thickness direction phase difference value (Rth) was measured based on external light (Θ) incident at an incident angle of 60° to one side of the display device (10). The results are shown in FIGS. 16 and 17, and Tables 1 and 2 below. In Tables 1 and 2 below, 'φ' represents a phase delay value due to external light incident in a direction perpendicular to one side of the display device (10), and 'Θ' represents a phase delay value due to external light incident at an incident angle of 60° to one side of the display device (10). Light having a wavelength of 550 nm was used as the light incident on the display device (10).

Layer Optical axis (Θ, φ) Phase delay
(nm, @550nm) 1 Polarizing film (310) 0, 45°(transmission) 0 2 Phase difference film (330) -λ/4 plate 0, 135°(delay) 140(R ₀ ) 3 Thin film encapsulation layer (ENL) 90, 0°(delay) -70(Rth)

Layer Optical axis (Θ, φ) Phase delay
(nm, @550nm) 1 Polarizing film (310) 0, 45°(transmission) 0 2 2nd phase difference film (350) -λ/2 plate 0, 152.2°(delay) 234(R ₀ ) 3 Phase difference film (330) -λ/4 plate 0, 122.5°(lag) 116(R ₀ ) 4 Thin film encapsulation layer (ENL) 90, 0°(delay) -60(Rth)

Referring to FIG. 16, FIG. 17, Table 1, and Table 2, it was found that the polarizing film (310) transmits only some light traveling in a specific direction without phase delay for the incident external light. In the case of the phase difference film (330), it was found that the phase is delayed and circularly polarized for external light (φ) incident in a vertical direction among the light transmitted by the polarizing film (310), and in the case of the thin film encapsulation layer (ENL), it was found that the phase is delayed and circularly polarized for external light (Θ) incident at an incident angle of 60°.

Next, an external light reflectance experiment of the display device (10) was performed and the results are shown in Figs. 18 to 20. The external light reflectance experiment measured the external light reflectance when external light (Θ) incident in a direction not perpendicular to one surface of the display device (10) was incident, based on the case where the reflectance of external light (φ) incident in a direction perpendicular to one surface was 0.

FIG. 18 is a graph showing the luminance deviation of reflected light representing the results of an external light reflection experiment of the display device of FIG. 2. FIG. 19 is a graph showing the luminance deviation of reflected light representing the results of an external light reflection experiment of the display device of FIG. 14. FIG. 20 is a graph showing the luminance deviation of reflected light representing the results of an external light reflection experiment of the display device according to one embodiment.

Fig. 18 shows the results of measuring external light reflectance of the display device (10) of Fig. 2, Fig. 19 shows the results of measuring the external light reflectance of the display device (10_1) of Fig. 14, and Fig. 20 shows the results of measuring the external light reflectance of the display device (10) of Fig. 2 excluding the thin film encapsulation layer (ENL).

FIGS. 18 to 20 illustrate the results of measuring external light reflectance according to the viewing angle of the display device (10), where the viewing angle is indicated on the horizontal axis in the range of 0° to 70°, and the color distribution illustrated on the right means that the reflectance increases from blue to red or green. Referring to FIGS. 18 to 20, it can be seen that the graphs of FIGS. 18 and 19 show a significant decrease in reflectance in the range of the viewing angle of 60° to 70°, compared to the graph of FIG. 20. Through this, it can be seen that the display device (10) according to one embodiment includes a thin film encapsulation layer (ENL) having a phase difference function of a +C plate, thereby having the effect of preventing side external light reflection and improving side visibility of the display device (10).

Although the embodiments of the present invention have been described with reference to the attached drawings, those skilled in the art will understand that the present invention can be implemented in other specific forms without changing the technical idea or essential features of the present invention. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

10: Display device
100: Display Panel
300: Optical Absence
500: Cover Window

Claims (20)

substrate;
A thin film transistor layer disposed on the above substrate;
A light emitting element layer disposed on the thin film transistor layer; and
Including a thin film encapsulation layer disposed on the light emitting element layer,
The above thin film encapsulation layer comprises an encapsulation organic film comprising an acrylic copolymer containing an aromatic ring,
The above acrylic copolymer is formed by copolymerizing a first monomer having a hydrocarbon group having 1 to 30 carbon atoms and a second monomer having a hydrocarbon group having 1 to 30 carbon atoms, including at least one aromatic ring compound.
The first monomer and the second monomer each contain at least one acrylic functional group,
The above acrylic functional group includes at least one of an acrylate group, an acrylamide group, an acrylnitile group, and a methacrylate group,
The above first monomer is an acrylic monomer containing an alkyl group or alkylene group having 10 to 20 carbon atoms,
A display device wherein the second monomer is an acrylic monomer containing an alkyl group or alkylene group having 1 to 10 carbon atoms and at least one aromatic ring compound. In the first paragraph,
A display device in which the above thin film encapsulation layer satisfies the following equation 1.
[Formula 1]
nz≠nx=ny
(Here, 'nx' is the refractive index of the thin film encapsulation layer in the X-axis direction, which is the longitudinal axis of the thin film encapsulation layer, 'ny' is the refractive index of the thin film encapsulation layer in the Y-axis direction, which is the width direction axis of the thin film encapsulation layer perpendicular to the X-axis, and 'nz' is the refractive index of the thin film encapsulation layer in the Z-axis direction, which is the thickness direction axis of the thin film encapsulation layer perpendicular to the X-axis and the Y-axis.) In the second paragraph,
A display device in which the above thin film encapsulation layer is a +C plate satisfying the following equation 2.
[Formula 2]
nz>nx=ny In the third paragraph,
A display device in which the thickness direction phase difference value (Rth) of the above thin film encapsulation layer has a range of -275 nm to 0 nm based on a wavelength of 550 nm. In the fourth paragraph,
A display device in which the thickness direction phase difference value (Rth) of the above thin film encapsulation layer has a range of -80 nm to -20 nm based on a wavelength of 550 nm. In the first paragraph,
Further comprising an optical member disposed on the above thin film encapsulation layer,
A display device in which the optical member includes a phase difference film of a +A plate disposed on the thin film encapsulation layer. In Article 6,
A display device wherein the above phase difference film includes at least one of a quarter wave plate (λ/4 plate) or a half wave plate (λ/2 plate). In Article 7,
The above thin film encapsulation layer comprises a first encapsulation inorganic film disposed between the encapsulation organic film and the light emitting element layer; and
A display device further comprising a second inorganic membrane disposed on the organic membrane of the bag. In Article 8,
A display device further comprising a touch sensor layer disposed between the second bag-type inorganic film and the phase difference film. delete delete In the first paragraph,
An indicator device wherein the first monomer is represented by the following chemical formula 1, and the second monomer is represented by the following chemical formula 2.
[Chemical Formula 1]

[Chemical formula 2]
In the first paragraph,
A display device wherein the acrylic copolymer is formed by copolymerizing 20 to 40 parts by weight of the first monomer and 60 to 80 parts by weight of the second monomer. In Article 13,
A display device wherein the above acrylic copolymer is formed by copolymerizing 35 parts by weight of the first monomer and 65 parts by weight of the second monomer. display panel;
A polarizing film disposed on the above display panel; and
At least one +A plate phase difference film disposed between the polarizing film and the display panel,
The above display panel
substrate;
A thin film transistor layer disposed on the above substrate;
A light emitting element layer disposed on the thin film transistor layer; and
Including a thin film encapsulation layer disposed on the light emitting element layer,
The above thin film encapsulation layer includes an encapsulation organic film having a thickness direction phase difference value (Rth) in the range of -275 nm to 275 nm based on a wavelength of 550 nm,
The above-mentioned encapsulated organic film comprises an acrylic copolymer containing an aromatic ring,
The above acrylic copolymer is formed by copolymerizing a first monomer having a hydrocarbon group having 1 to 30 carbon atoms and a second monomer having a hydrocarbon group having 1 to 30 carbon atoms, including at least one aromatic ring compound.
The first monomer and the second monomer each contain at least one acrylic functional group,
The above acrylic functional group includes at least one of an acrylate group, an acrylamide group, an acrylnitile group, and a methacrylate group,
The above first monomer is an acrylic monomer containing an alkyl group or alkylene group having 10 to 20 carbon atoms,
A display device wherein the second monomer is an acrylic monomer comprising an alkyl group or alkylene group having 1 to 10 carbon atoms and at least one aromatic ring compound. delete In Article 15,
An indicator device wherein the first monomer is represented by the following chemical formula 1, and the second monomer is represented by the following chemical formula 2.
[Chemical Formula 1]

[Chemical formula 2]
In Article 17,
A display device wherein the above acrylic copolymer is formed by copolymerizing 35 parts by weight of the first monomer and 65 parts by weight of the second monomer. In Article 15,
A display device wherein the above phase difference film includes at least one of a quarter wave plate (λ/4 plate) or a half wave plate (λ/2 plate). In Article 19,
The above display panel further includes a touch sensor layer disposed on the thin film encapsulation layer,
A display device in which the thickness direction phase difference value (Rth) of the above thin film encapsulation layer has a range of -80 nm to -20 nm based on a wavelength of 550 nm.

Images