Display device and method for manufacturing the same

Abstract

A display device and a method of manufacturing the same are provided. In the method of manufacturing the display device, the method includes: providing a first mother substrate; forming a pixel layer including light-emitting devices on the first mother substrate; providing a second mother substrate; forming a diffraction pattern layer on the second mother substrate configured to diffract light emitted from the light-emitting devices; forming a combined substrate structure by bonding the first mother substrate and the second mother substrate, with the pixel layer formed on the first mother substrate and the diffraction pattern layer formed on the second mother substrate; forming a plurality of unit substrate structures each including a first substrate and a second substrate by cutting the combined substrate structure, with the pixel layer formed on the first substrate and the diffraction pattern layer formed on the second substrate; forming a protective member on the diffraction pattern layer; and removing foreign matter on the diffraction pattern layer with the protective member.

Description

Technical Field

[0001] Aspects of one or more embodiments relate to a display device and a method of manufacturing the display device. Background Art

[0002] With the development of multimedia, the importance of display devices has increased. In response to the increased importance of display devices, various display devices such as liquid crystal displays (LCDs) and organic light emitting displays (OLEDs) have been used.

[0003] Among display devices, an organic light emitting display displays an image by using an organic light emitting device that emits light through the recombination of electrons and holes. The organic light emitting display has characteristics such as a relatively high response speed, a relatively high brightness, and a relatively wide viewing angle, and at the same time can be driven with relatively low power consumption.

[0004] The above information disclosed in this background art section is only for enhancing the understanding of the background, and thus, it may contain information that does not constitute the prior art. Summary of the Invention

[0005] Aspects of one or more example embodiments include a display device and a method of manufacturing the display device, in which an effective emission area ratio can be increased, and visibility defects caused by foreign substances can be minimized or reduced.

[0006] Additional features will be partially set forth in the description below, and will be partially apparent from the description, or may be learned by practice of the given embodiments.

[0007] According to some example embodiments, a method of manufacturing a display device includes: providing a first mother substrate; forming a pixel layer including a light emitting device on the first mother substrate; providing a second mother substrate; forming a diffraction pattern layer on the second mother substrate configured to diffract light emitted from the light emitting device; forming a combined substrate structure by bonding the first mother substrate and the second mother substrate, the pixel layer being formed on the first mother substrate and the diffraction pattern layer being formed on the second mother substrate; forming a plurality of unit substrate structures each including a first substrate and a second substrate by cutting the combined substrate structure, the pixel layer being formed on the first substrate and the diffraction pattern layer being formed on the second substrate; forming a protection member for preventing foreign substances on the diffraction pattern layer; and removing foreign substances on the diffraction pattern layer.

[0008] According to some example embodiments, the step of forming the protection member may include forming a sacrificial layer on the diffraction pattern layer, and the step of removing foreign substances may include removing the sacrificial layer.

[0009] According to some example embodiments, the step of forming a protective member may include forming a coating layer over the diffraction pattern layer, and the step of removing foreign substances may include cleaning the coating layer.

[0010] According to some example embodiments, the step of forming a protective member may include forming a sacrificial layer covering the diffraction pattern layer between the step of forming the diffraction pattern layer and the step of forming the bonded substrate structure, and the step of removing foreign substances may include removing the sacrificial layer after the step of forming a plurality of unit substrate structures.

[0011] According to some example embodiments, the method may further include performing seal printing and baking on a surface facing away from the surface of the sacrificial layer of the second mother substrate between the step of forming the sacrificial layer and the step of forming the bonded substrate structure.

[0012] According to some example embodiments, between the step of forming the bonded substrate structure and the step of forming a plurality of unit substrate structures, the method may further include: forming a protective layer on the sacrificial layer of the second mother substrate; thinning the first mother substrate; removing the protective layer on the second mother substrate; cleaning the bonded substrate structure; and forming a protective layer on the first mother substrate.

[0013] According to some example embodiments, the method may further include polishing a plurality of unit substrate structures between the step of forming a plurality of unit substrate structures and the step of removing the sacrificial layer.

[0014] According to some example embodiments, the step of forming a protective member may include forming a sacrificial layer covering the diffraction pattern layer between the step of forming the diffraction pattern layer and the step of forming the bonded substrate structure; and the step of removing foreign substances may include removing the sacrificial layer between the step of forming the bonded substrate structure and the step of forming a plurality of unit substrate structures.

[0015] According to some example embodiments, between the step of forming the bonded substrate structure and the step of removing the sacrificial layer, the method may further include: forming a protective layer on the sacrificial layer of the second mother substrate; thinning the first mother substrate; removing the protective layer of the second mother substrate; cleaning the bonded substrate structure; and forming a protective layer on the first mother substrate.

[0016] According to some example embodiments, the method may include forming a plurality of unit substrate structures after the step of removing the sacrificial layer.

[0017] According to some example embodiments, the step of forming a protective member may include forming a sacrificial layer covering the diffraction pattern layer after the step of forming the bonded substrate structure, and the step of removing foreign substances may include removing the sacrificial layer between the step of forming the sacrificial layer and the step of forming a plurality of unit substrate structures.

[0018] According to some example embodiments, between the step of forming the sacrificial layer and the step of removing the sacrificial layer, the method may further include: forming a protective layer on the sacrificial layer of the second mother substrate; thinning the first mother substrate; removing the protective layer of the second mother substrate; cleaning the bonded substrate structure; and forming a protective layer on the first mother substrate.

[0019] According to some example embodiments, the method may include forming a plurality of unit substrate structures after the step of removing the sacrificial layer.

[0020] According to some example embodiments, the step of forming the protection member may include forming a sacrificial layer covering the diffraction pattern layer between the step of forming the bonded substrate structure and the step of forming a plurality of unit substrate structures, and the step of removing foreign substances may include removing the sacrificial layer after the step of forming a plurality of unit substrate structures.

[0021] According to some example embodiments, between the step of forming the sacrificial layer and the step of forming a plurality of unit substrate structures, the method may further include: forming a protective layer on the sacrificial layer of the second mother substrate; thinning the first mother substrate; removing the protective layer of the second mother substrate; cleaning the bonded substrate structure; and forming a protective layer on the first mother substrate.

[0022] According to some example embodiments, the step of forming the protection member may include forming a coating layer covering the diffraction pattern layer between the step of forming the bonded substrate structure and the step of forming a plurality of unit substrate structures, and the step of removing foreign substances may include cleaning the coating layer after the step of forming a plurality of unit substrate structures.

[0023] According to some example embodiments, between the step of forming the bonded substrate structure and the step of forming a plurality of unit substrate structures, the method may further include: forming a protective layer above the diffraction pattern layer of the second mother substrate; thinning the first mother substrate; removing the protective layer of the second mother substrate; cleaning the bonded substrate structure; and forming a protective layer on the first mother substrate.

[0024] According to some example embodiments, the method may further include polishing the plurality of unit substrate structures between the step of forming the plurality of unit substrate structures and the step of cleaning the coating layer.

[0025] According to some example embodiments, a display device includes: a first substrate on which a pixel layer including light-emitting devices is disposed; a packaging layer located on the pixel layer; a diffraction pattern layer that diffracts light emitted from the light-emitting devices onto the packaging layer; and a protection member located on the diffraction pattern layer.

[0026] According to some example embodiments, the protection member may include a waterproof material and an oil-proof material. Description of the Drawings

[0027] These and / or other aspects will become apparent and more readily appreciated from the following description of some example embodiments, taken in conjunction with the accompanying drawings, in which:

[0028] Figure 1 is a cross-sectional view schematically showing a display device according to some example embodiments;

[0029] Figure 2 shows Figure 1 an enlarged plan view and cross-sectional view of the light-emitting device shown in;

[0030] Figure 3 is a schematic perspective view showing a packaging layer and a diffraction pattern layer according to some example embodiments;

[0031] Figure 4 is Figure 3 a top plan view of the diffraction pattern layer shown in;

[0032] Figure 5 is along Figure 4 a cross-sectional view of a part of the diffraction pattern layer taken along the line I-I' shown in;

[0033] Figure 6 is a cross-sectional view showing a part of the diffraction pattern layer taken along the dashed line IL shown in; Figure 5 is

[0034] Figure 7 a diagram schematically showing an enlarged emission region for describing according to some example embodiments;

[0035] Figure 8 shows a head-mounted display device including the display device shown in; Figure 1 according to some example embodiments;

[0036] Figure 9 is a schematic diagram showing a process of manufacturing a display device according to some example embodiments;

[0037] Figure 10 is for describing Figure 9 a view of the bonding operation among the processes shown in;

[0038] Figure 11 and Figure 14 are both schematic diagrams showing a process of manufacturing a display device according to some example embodiments;

[0039] Figure 12 、 Figure 13A and Figure 13B are schematic diagrams showing Figure 11 a cross-sectional view and a perspective view of a sacrificial layer forming operation among the processes shown in;

[0040] Figure 15 and Figure 21 are schematic diagrams each showing a process of manufacturing a display device according to some example embodiments;

[0041] Figures 16 to 20 schematically shows Figure 15 a cross-sectional view of a sacrificial layer formation operation and a sacrificial layer removal operation among the processes shown in

[0042] Figure 22 is a schematic diagram showing a process of manufacturing a display device according to some example embodiments;

[0043] Figure 23 schematically shows a display device formed according to the process shown in Figure 22 ; and

[0044] Figure 24 and Figure 25 are each schematic diagrams showing a process of manufacturing a display device according to some example embodiments. DETAILED DESCRIPTION

[0045] Since embodiments allow various changes and many embodiments, some example embodiments will be shown in the drawings and some example embodiments will be described in detail in the written description. Referring to the example embodiments described in more detail in conjunction with the drawings, the features of some example embodiments and the methods of implementing the features may become more apparent. However, the embodiments are not limited to the example embodiments set forth herein and may be implemented in various forms.

[0046] Hereinafter, aspects of some example embodiments will be described in more detail with reference to the drawings. The same reference numerals denote the same components and their repeated description will be omitted.

[0047] It will be understood that although the terms "first", "second", etc. may be used herein to describe various components, these components should not be limited by these terms. These terms are only used to distinguish one component from another.

[0048] As used herein, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are also intended to include the plural forms.

[0049] It will also be understood that the terms "comprising" and / or "having" as used herein specify the presence of the stated features or components, but do not preclude the presence or addition of one or more other features or components.

[0050] It will be understood that when a layer, region or component is referred to as being "formed on" another layer, region or component, the layer, region or component can be directly formed or indirectly formed on the other layer, region or component. That is, for example, there can be intermediate layers, regions or components.

[0051] For ease of explanation, the dimensions of components in the drawings may be exaggerated. In other words, since the dimensions and thicknesses of the components in the drawings are arbitrarily shown for ease of explanation, the following embodiments are not limited thereto.

[0052] When a specific embodiment can be implemented differently, the specific process order can be performed differently from the described order. For example, two consecutively described processes can be performed substantially simultaneously or in an order opposite to or different from the described order, unless otherwise explicitly or implicitly stated.

[0053] In the embodiments described herein, when a layer, region or component is connected to another layer, region or component, these layers, regions or components can be directly connected to each other, or these layers, regions or components can also be indirectly connected to each other, and another layer, region or component is located between them. For example, in this specification, when a layer, region or component is electrically connected to another layer, region or component, these layers, regions or components can be directly electrically connected to each other, or these layers, regions or components can also be indirectly electrically connected to each other, and another layer, region or component is located between them.

[0054] Figure 1 is a cross-sectional view schematically showing a display device 10 according to some example embodiments. Figure 2 shows Figure 1 an enlarged view of the plan and cross-section of the light-emitting device 120 shown in

[0055] Hereinafter, an organic light-emitting display device is described as an example of the display device 10 according to some example embodiments, but the display device 10 according to the embodiments is not limited thereto. According to some example embodiments, various types of display devices can be used, such as an inorganic light-emitting display (or inorganic EL display) or a quantum dot light-emitting display.

[0056] Referring to Figure 1 and Figure 2 , the display device 10 according to some example embodiments can include: a substrate 110; a pixel layer in which a light-emitting device 120 is disposed; a packaging layer 160 located above the pixel layer; and a diffraction pattern layer 170.

[0057] The substrate 110 may include various materials such as glass, metal, and plastic. The substrate 110 may include an insulating substrate. For example, the substrate 110 may include a polymer resin such as polyethersulfone (PES), polyacrylate, polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyarylate (PAR), polyimide (PI), polycarbonate (PC), or cellulose acetate propionate (CAP). The substrate 110 may include a flexible substrate.

[0058] A plurality of light-emitting devices 120 may be disposed in a pixel layer on the substrate 110. The light-emitting device 120 may include a first electrode 121 as a pixel electrode, an intermediate layer 123, and a second electrode 125 as a counter electrode. According to some example embodiments, in the pixel layer, at least one insulating layer and a pixel circuit electrically connected to the light-emitting device 120 may be disposed between the substrate 110 and the light-emitting device 120. The pixel circuit may include at least one thin-film transistor and a capacitor.

[0059] The first electrode 121 may include a conductive oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium oxide (In2O3), indium gallium oxide (IGO), and aluminum zinc oxide (AZO). As another embodiment, the first electrode 121 may include a reflective film including silver (Ag), magnesium (Mg), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), or a combination thereof. As another embodiment, the first electrode 121 may further include a film located on / under the reflective film and including ITO, IZO, ZnO, or In2O3.

[0060] The edge of the first electrode 121 may be covered by a pixel defining layer 130. The pixel defining layer 130 may include an opening OP exposing a part of the first electrode 121. The pixel defining layer 130 may include an organic material or an inorganic material. As an embodiment, the pixel defining layer 130 may include materials such as photoresist, polyimide resin, acrylic resin, silicon compound, and methacrylic resin.

[0061] Figure 2 An embodiment is shown in which the first electrode 121 and the opening OP have a substantially rhombic shape. The shapes of the first electrode 121 and the opening OP may vary according to the arrangement of the light-emitting device 120 and the like.

[0062] The intermediate layer 123 includes an emission layer. The emission layer may include a polymeric organic material or a low-molecular-weight organic material that emits light of a specific color. In an embodiment, the intermediate layer 123 may include a first functional layer disposed below the emission layer and / or a second functional layer disposed on the emission layer. The first functional layer and / or the second functional layer may include a layer integrally formed above the plurality of first electrodes 121, or may include a layer patterned to correspond to the plurality of first electrodes 121.

[0063] The first functional layer may include a single layer or multiple layers. For example, when the first functional layer includes a polymeric material, the first functional layer may be a hole transport layer (HTL) having a single-layer structure and includes poly(3,4-ethylenedioxythiophene) or polyaniline (PANI). When the first functional layer includes a low-molecular-weight material, the first functional layer may include a hole injection layer (HIL) and a hole transport layer (HTL).

[0064] The second functional layer is not necessarily provided. For example, when both the first functional layer and the emission layer include polymeric materials, it is desirable to form the second functional layer to impart excellent characteristics to the organic light-emitting diode. The second functional layer may include a single layer or multiple layers. The second functional layer may include an electron transport layer (ETL) and / or an electron injection layer (EIL).

[0065] The second electrode 125 is disposed to face the first electrode 121, and the intermediate layer 123 is located between the first electrode 121 and the second electrode 125. The second electrode 125 may include a conductive material having a small work function. For example, the second electrode 125 may include a semi-transparent layer including Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, lithium (Li), calcium (Ca), or an alloy thereof. Optionally, the second electrode 125 may further include a layer including ITO, IZO, ZnO, and In2O3 on the semi-transparent layer including the above materials. The second electrode 125 may be integrally formed for the plurality of light-emitting devices 120 and face the plurality of first electrodes 121.

[0066] The buffer layer 150 may be disposed on the second electrode 125. The buffer layer 150 may have a form in which an organic layer and / or an inorganic layer are stacked in a single-layer structure or a multi-layer structure. According to some example embodiments, the buffer layer 150 may further include an air layer. When the buffer layer 150 is an air layer, no specific structure is disposed between the second electrode 125 and the encapsulation layer 160. According to some example embodiments, the buffer layer 150 may also be used to adjust the distance between the diffraction pattern layer 170 (to be described later) and the plurality of light-emitting devices 120.

[0067] According to some example embodiments, a capping layer may be disposed on the second electrode 125. The capping layer may prevent light incident on the second electrode 125 from being lost due to total reflection. According to some example embodiments, the capping layer may include an organic layer or an inorganic layer.

[0068] The encapsulation layer 160 may be disposed to cover the plurality of light-emitting devices 120. That is, the plurality of light-emitting devices 120 may be disposed between the first substrate 110 and the encapsulation layer 160. The encapsulation layer 160 may protect the light-emitting devices 120 from external oxygen or moisture.

[0069] According to some example embodiments, the encapsulation layer 160 may include a transparent insulating substrate. The encapsulation layer 160 may include a glass substrate, a quartz substrate, a transparent resin substrate, etc. A sealing member may be disposed between the encapsulation layer 160 and the substrate 110 to bond the encapsulation layer 160 and the substrate 110. According to some example embodiments, the encapsulation layer 160 may include at least one organic encapsulation layer and at least one inorganic encapsulation layer. For example, the encapsulation layer 160 may include a first inorganic encapsulation layer / organic encapsulation layer / second inorganic encapsulation layer. The number of organic encapsulation layers, the number of inorganic encapsulation layers, and the order of stacking these layers may be modified. The first inorganic encapsulation layer and the second inorganic encapsulation layer may each include more than one inorganic insulating material among alumina, titanium oxide, tantalum oxide, hafnium oxide, zinc oxide, silicon oxide, silicon nitride, and silicon oxynitride. The organic encapsulation layer may include a polymeric material. The polymeric material may include an acrylic resin, an epoxy resin, a polyimide, polyethylene, etc.

[0070] The diffraction pattern layer 170 may be disposed on the encapsulation layer 160. The diffraction pattern layer 170 may be disposed on the path of light emitted from the plurality of light-emitting devices 120. The diffraction pattern layer 170 may include a plurality of diffraction patterns 171. The plurality of diffraction patterns 171 may diffract the light emitted from the light-emitting devices 120 and increase the emission area. The plurality of diffraction patterns 171 may include a periodic pattern. The plurality of diffraction patterns 171 may all have the same shape. The diffraction pattern layer 170 may include an inorganic material such as silicon nitride. In an embodiment, the diffraction pattern layer 170 may be formed by etching the upper surface of the inorganic encapsulation layer included in the encapsulation layer 160. In another embodiment, the diffraction pattern layer 170 may be separately disposed on the encapsulation layer 160. According to some example embodiments, a buffer layer may also be disposed between the diffraction pattern layer 170 and the encapsulation layer 160. The buffer layer may include a single-layer or multi-layer structure including at least one organic layer and / or at least one inorganic layer.

[0071] Figure 3 is a schematic perspective view showing the encapsulation layer 160 and the diffraction pattern layer 170 according to some example embodiments. Figure 4 is Figure 3 a top plan view of the diffraction pattern layer 170 shown inFigure 5 is a cross-sectional view of a part of the diffraction pattern layer 170 taken along the line I-I' shown in Figure 4 . Figure 6 is a cross-sectional view of a part of the diffraction pattern layer 170 taken along the dashed line IL shown in Figure 5 .

[0072] Referring to Figures 3 to 6 , the diffraction pattern layer 170 may include a plurality of diffraction patterns 171 disposed on the encapsulation layer 160. The diffraction patterns 171 may have a thickness (e.g., a predetermined thickness) t. The thickness t represents the distance from the bottom surface to the top surface of the diffraction pattern 171. The diffraction patterns 171 may have a specific length d. The length d represents the width of the cross-section of the diffraction pattern 171. The diffraction patterns 171 may be arranged to have a specific period α. The period α represents the distance from one side of one of two adjacent diffraction patterns 171 to the other side of the other diffraction pattern 171. The period α and the length d of each diffraction pattern 171 are defined with reference to a cross-section taken along the dashed line IL passing through half t / 2 of the thickness t of each diffraction pattern 171.

[0073] Figure 3 An example is shown in which a plurality of diffraction patterns 171 protrude from the encapsulation layer 160 and all have a cylindrical shape in which the top surface and the bottom surface are circular in shape. The circular shape may also include an oval or a polygon that is substantially close to a circle. The plurality of diffraction patterns 171 may have various shapes. For example, the diffraction pattern 171 may protrude from the encapsulation layer 160 and have a hemispherical shape with a circular cross-section, a hexahedral shape with a quadrilateral cross-section, or a trapezoidal shape, and may be a hole that is etched and passes through toward the encapsulation layer 160 and has a circular or quadrilateral cross-section, etc.

[0074] Figure 7 is a diagram schematically showing an enlarged emission region for describing an embodiment. For ease of explanation, some components shown in Figure 1 are omitted.

[0075] Referring to Figure 7 , the emission pattern formed by the light L1 emitted from the light-emitting device 120 in the first region TA1 is defined as the first emission pattern EP1, and the emission pattern formed by the light transmitted through the diffraction pattern layer 170 (i.e., the first diffracted light L2a, the second diffracted light L2b, and the third diffracted light L2c) in the second region TA2 is defined as the second emission pattern EP2. Due to the refractive indices of the encapsulation layer 160 and the buffer layer 150, the path of the light L1 may be changed at a specific angle.

[0076] The first diffracted light L2a, the second diffracted light L2b, and the third diffracted light L2c may respectively include a zero-order diffracted light L2a1, L2b1, and L2c1 and a first-order diffracted light L2a2, L2a3, L2b2, L2b3, L2c2, and L2c3. The zero-order diffracted light has an optical path that is unchanged before and after being diffracted by the diffractive pattern layer 170. The first-order diffracted light is light that has an optical path changed by the diffractive pattern layer 170 and has a second diffraction angle θ2 with respect to the zero-order diffracted light. In another embodiment, the first diffracted light L2a, the second diffracted light L2b, and the third diffracted light L2c may each further include diffracted light having an order equal to or higher than the second order. The diffractive pattern layer 170 may generate a first effective light L2al, a second effective light L2b3, and a third effective light L2c2 that all have optical paths in the vertical direction by diffracting the light L1. Accordingly, the second emission pattern EP2 may have a reference emission pattern Pref and a plurality of reproduced emission patterns P1 to P8 reproduced from the reference emission pattern Pref. Here, the vertical direction may be completely perpendicular to the first substrate 110 and may also include a substantially (almost) vertical direction. At the same time, when the effective light has an optical path in a direction perpendicular to the first substrate 110, the order of the diffracted light is not limited. In other words, the effective light having an optical path in the vertical direction may include both the zero-order diffracted light and the first-order diffracted light.

[0077] At the same time, the area (square measure) of the first region TA1 is the same as the area (square measure) of the second region TA2. However, the number of emission patterns included in the second region TA2 is greater than the number of emission patterns included in the first region TA1. This means that the emission region in the second region TA2 is wider than the emission region in the first region TA1. In other words, it may also be expressed that the region where light is not emitted (i.e., the non-emission region) is smaller in the second region TA2 than in the first region TA1.

[0078] A relatively wide emission region may be expressed as having a high effective emission area ratio. The effective emission area (square measure) ratio is defined as the ratio of the area (square measure) of the emission patterns present in a region to the area (square measure) of the said region. Here, the emission patterns used to calculate the effective emission area ratio may include both the reference emission pattern and the reproduced emission patterns. For example, the second region TA2 includes nine emission patterns (i.e., the reference emission pattern Pref and a plurality of reproduced emission patterns P1 to P8), while the first region TA1 includes only one emission pattern. Accordingly, the effective emission area ratio of the second region TA2 is greater than the effective emission area ratio of the first region TA1. The brightness of the reference emission pattern Pref and the brightness of the first reproduced emission pattern P1 may be different from each other. However, the reproduced emission patterns used to calculate the effective emission area ratio may be defined as emission patterns having a brightness of approximately 3% or more of the brightness of the reference emission pattern Pref.

[0079] The diffraction distance β can be determined based on the distance Z between the light-emitting device 120 and the diffraction pattern layer 170, the refractive index of the components (the buffer layer 150 and the encapsulation layer 160) between the light-emitting device 120 and the diffraction pattern layer 170, the period α of the diffraction pattern 171, the first diffraction angle θ1, the second diffraction angle θ2, and the like. When the thickness of the buffer layer 150 is small enough to be negligible, the diffraction distance β can be determined based on the thickness Z EN of the encapsulation layer 160, the refractive index nEN of the encapsulation layer 160, the period α of the diffraction pattern 171, the second diffraction angle θ2, and the wavelength λ of the light L1, as shown in the following equations (1) and (2).

[0080]

[0081]

[0082] Figure 8 shows a head-mounted display device 20 including the display device 10 according to some example embodiments Figure 1 as shown in.

[0083] Referring to Figure 8 , the head-mounted display device 20 according to some example embodiments may include Figure 1 the display device 10 as shown in as a display unit, and further includes a lens 12.

[0084] Light may be incident on the lens 12 from the display device 10. According to some example embodiments, the lens 12 may be disposed between the object and the user. According to some example embodiments, the lens 12 may include an opaque lens to implement virtual reality. In another embodiment, the lens 12 may include a transparent lens or a translucent lens to implement augmented reality. Meanwhile, in an embodiment, the lens 12 may include a converging lens. The user may view the magnified image of the display device 10 through the lens 12.

[0085] Figure 9 is a schematic diagram showing a process of manufacturing the display device 10 according to some example embodiments. Figure 10 is for describing Figure 9 the bonding operation among the processes shown in. In Figure 9 , an example is described in which the encapsulation layer 160 is an insulating substrate.

[0086] When providing a first mother substrate 110M (see Figure 10)(In S31), a pixel layer including a plurality of light-emitting devices 120 may be formed on the first mother substrate 110M (S33). A pixel circuit may be formed on the first mother substrate 110M, and the light-emitting device 120 may be formed on the pixel circuit such that the light-emitting device 120 is electrically connected to the pixel circuit. The first mother substrate 110M may be a mother substrate that can be used to simultaneously manufacture a plurality of substrates 110.

[0087] Meanwhile, when providing the second mother substrate 160M (see Figure 10 )(In S41), a diffraction pattern layer 170 including a plurality of diffraction patterns 171 may be formed on the surface of the second mother substrate 160M (S43). The second mother substrate 160M may be a mother substrate that can be used to simultaneously manufacture a plurality of encapsulation layers 160. A key may be formed by depositing a metal such as molybdenum (Mo) on the surface of the second mother substrate 160M using a sputtering method or the like and patterning the metal, and the diffraction pattern 171 may be formed based on the key. The diffraction pattern 171 may be formed by depositing an inorganic material such as silicon dioxide (SiO2) in a chemical vapor deposition (CVD) method or the like and patterning the inorganic material.

[0088] The second mother substrate 160M may be cut and divided to match the size of the first mother substrate 110M (S45). Wet cleaning and plasma cleaning may be performed on the divided second mother substrate 160M (S47). Printing and baking of the first sealant and printing of the second sealant may be continuously performed on the other surface of the cleaned second mother substrate 160M (the surface opposite to the surface on which the diffraction pattern 171 is formed). The first sealant is a panel unit sealant, and the second sealant is a mother substrate unit sealant.

[0089] Next, as shown in Figure 10 , a combined substrate structure may be formed by aligning and bonding the first mother substrate 110M and the second mother substrate 160M (S51), with the pixel layer formed on the first mother substrate 110M and the diffraction pattern layer 170 formed on the second mother substrate 160M. Curing of the first sealant and curing of the second sealant may be performed on the combined substrate structure (S53). The second sealant may be cured with ultraviolet light, and the first sealant may be cured with a laser.

[0090] Next, a protective film can be attached to the diffraction pattern layer 170 of the second mother substrate 160M (S55), and a thinning operation of physical / chemical treatment such as etching can be performed on the first mother substrate 110M (S57). An insulating substrate can be additionally attached on top of the protective film. After performing the thinning operation on the first mother substrate 110M, a peeling operation can be performed to remove the protective film (or the insulating substrate and the protective film) of the second mother substrate 160M (S59). After the peeling operation, the bonded substrate structure can be cleaned (S61). Next, a protective layer can be formed on the first mother substrate 110M by using a screen printer (S63), and a thermal curing operation can be performed on the protective layer (S65).

[0091] Next, the bonded substrate structure can be cut into a plurality of unit substrate structures (S67). A first polishing process (S69) and a second polishing process (S73) can be performed on each unit substrate structure. The first polishing process is a process of forming a chamfered surface on the substrate by pressing and trimming the edge surface of the unit substrate structure at a predetermined angle and a predetermined depth. The second polishing process is a process of more finely polishing the edge surface of the unit substrate structure. To enhance the encapsulation function, a strengthening seal can be performed between the first polishing process and the second polishing process (S71). Next, defective products can be selected by performing multiple inspections on the unit substrate structures (S75), and the unit substrate structures that pass the inspection can be encapsulated (S77).

[0092] When performing a plurality of subsequent operations on the bonded substrate structure, foreign substances may be adsorbed by the diffraction pattern layer 170, and thus, the diffraction pattern layer 170 may be damaged. For example, it may be due to the cutting operation (S45) of the second mother substrate 160M before the bonding operation (S51), the lamination operation (S55), the peeling operation (S59), the cleaning operation (S61), the screen printing operation (S63), the unit cutting operation (S67), the first polishing process and the second polishing process (S69 and S73), and the strengthening seal operation (S71) after the bonding operation (S51), which may cause the adsorption of foreign substances. Environmental factors such as foreign substances and surface damage cause a reduction in the diffraction phenomenon of the display device 10, and when the display device 10 is applied to the head-mounted display device 20, foreign substances and the like may be seen in the image magnified by the lens 12.

[0093] According to some example embodiments, before some operations in the process of manufacturing the display device 10 in which the diffraction pattern layer 170 adsorbs foreign substances, an anti-foreign substance operation and a foreign substance removal operation may be further performed on the diffraction pattern layer 170. By doing so, adsorption of foreign substances by the diffraction pattern layer 170 can be prevented and / or minimized. The anti-foreign substance operation may include an operation of attaching a protective member such as a sacrificial layer or a coating layer on the diffraction pattern layer 170. The foreign substance removal operation may include an operation of removing or cleaning the protective member adsorbed with foreign substances.

[0094] Figure 11 is a schematic diagram showing a process of manufacturing the display device 10 according to an embodiment. Figure 12 、 Figure 13A and Figure 13B schematically show Figure 11 a cross-sectional view and a perspective view of a sacrificial layer formation operation in the process shown in

[0095] Figure 11 The process of manufacturing the display device 10 shown in Figure 9 differs from the process of manufacturing the display device 10 shown in Figure 9 in that a sacrificial layer formation operation (S44) and a sacrificial layer removal operation (S74a) are additionally performed. Hereinafter, some repetitive descriptions with reference to

[0096] With reference to Figure 11 , when the first mother substrate 110M (see Figure 10 )(S31) is provided, a pixel layer including the light-emitting device 120 may be formed on the first mother substrate 110M (S33). A pixel circuit may be formed on the first mother substrate 110M, and the light-emitting device 120 may be formed on the pixel circuit such that the light-emitting device 120 is electrically connected to the pixel circuit.

[0097] Meanwhile, when the second mother substrate 160M (see Figure 10 )(S41) is provided, a diffraction pattern layer 170 including a diffraction pattern 171 may be formed on the surface of the second mother substrate 160M (S43).

[0098] Next, as shown in Figure 12 , a sacrificial layer 180 covering the diffraction pattern layer 170 may be formed on the second mother substrate 160M (S44). The sacrificial layer 180 may be used as a protective member for protecting the diffraction pattern layer 170 in subsequent processes. The sacrificial layer 180 may include a material resistant to high temperatures. For example, the sacrificial layer 180 may include a metal such as molybdenum (Mo), a conductive oxide such as indium tin oxide (ITO) and indium zinc oxide (IZO), and a coating solution containing a high-temperature resistant material, and may be easily separated from the diffraction pattern layer 170. The sacrificial layer 180 may be formed on the diffraction pattern layer 170 by a sputtering method.

[0099] Next, the second mother substrate 160M having the sacrificial layer 180 formed thereon can be cut and divided to match the size of the first mother substrate 110M (S45). The divided second mother substrate 160M can be subjected to wet cleaning and plasma cleaning (S47). Printing and baking of the first sealant and printing of the second sealant can be continuously performed on the other surface of the cleaned second mother substrate 160M (the surface opposite to the surface on which the diffraction pattern 171 is formed) (S49).

[0100] Next, as Figure 10 shown, a combined substrate structure can be formed by aligning and bonding the first mother substrate 110M and the second mother substrate 160M (S51), with a pixel layer formed on the first mother substrate 110M and a diffraction pattern layer 170 formed on the second mother substrate 160M. Curing of the first sealant and the second sealant can be performed on the combined substrate structure (S53).

[0101] Next, a protective film can be attached on top of the sacrificial layer 180 of the second mother substrate 160M in the combined substrate structure by a lamination operation (S55), and a thinning operation can be performed on the first mother substrate 110M of the combined substrate structure by using a physical / chemical treatment such as etching (S57). After the thinning operation performed on the first mother substrate 110M, a peeling operation can be performed to remove the protective film of the second mother substrate 160M (S59). Next, the combined substrate structure can be cleaned (S61). Next, a protective layer can be formed on the first mother substrate 110M by using a screen printing machine (S63), and a thermal curing operation can be performed on the protective layer (S65).

[0102] Next, the combined substrate structure can be cut into a plurality of unit substrate structures (S67). Figure 13A An operation of cutting the combined substrate structure into a plurality of unit substrate structures is shown, Figure 13B which is a diagram showing a vertical cross-section of the unit substrate structure.

[0103] Referring to Figure 13A and Figure 13B, the combined base structure 100M may include a plurality of array regions AA, each array region AA including a display region DA within a first seal and a peripheral region PA surrounding the display region DA. Each array region AA corresponds to a panel unit and is formed as one display device. The display region DA is the region where the light-emitting devices 120 are arranged. The diffraction pattern 171 may be arranged to at least correspond to the display region DA. The combined base structure 100M may be cut along a virtual cutting line CL to form a plurality of unit base structures 10'. Each unit base structure 10' may include a base 110 on which a pixel layer is arranged and a packaging layer 160 on which a diffraction pattern layer 170 and a sacrificial layer 180 are arranged.

[0104] A first polishing process (S69) and a second polishing process (S73) may be performed on each unit base structure 10'. To enhance the encapsulation function of the unit base structure 10', a strengthened sealing (S71) may be performed between the first polishing process and the second polishing process.

[0105] After the first polishing process (S69) and the second polishing process (S73), the sacrificial layer 180 remaining on the packaging layer 160 in the unit base structure 10' may be removed (S74a). The sacrificial layer 180 may be removed by wet etching or dry etching and cleaning.

[0106] Next, defective products may be selected by performing multiple inspection operations on the unit base structure 10' (S75), and those unit base structures 10' that pass the inspection may be encapsulated (S77) as the display device 10 as shown in Figure 1 .

[0107] According to some example embodiments, as shown in Figure 11 , since the sacrificial layer 180 is formed after the formation of the diffraction pattern layer 170 and before bonding, subsequent processes at high temperatures such as sealing baking may be performed without causing damage to the diffraction pattern layer 170.

[0108] Figure 11 is an example where the sacrificial layer 180 is removed (S74a) after the cutting operation (S67). According to some example embodiments, as shown in Figure 14 , the sacrificial layer 180 may be removed (S66a) before the cutting operation (S67). In a state where the sacrificial layer 180 is removed, the combined base structure 100M may be cut along the virtual cutting line CL and divided into a plurality of unit base structures 10'. The first polishing process (S69), the strengthened sealing operation (S71), and the second polishing process (S73) may be continuously performed on each unit base structure 10' from which the sacrificial layer 180 has been removed.

[0109] Figure 15 is a schematic diagram showing a process of manufacturing a display device 10 according to an embodiment. Figures 16 to 20 schematically shows Figure 15 a cross-sectional view of a sacrificial layer formation operation and a sacrificial layer removal operation among the processes shown in

[0110] Figure 15 The process of manufacturing the display device 10 shown in Figure 9 differs from the process of manufacturing the display device 10 shown in Figure 9 in that: additionally, a sacrificial layer formation operation (S54) and a sacrificial layer removal operation (S66b) are performed. Hereinafter, some descriptions of repeated references Figure 9 will be omitted.

[0111] Referring to Figure 15 , when a first mother substrate 110M (see Figure 10 )(S31) is provided, a pixel layer including light emitting devices 120 may be formed on the first mother substrate 110M (S33). First, a pixel circuit may be formed on the first mother substrate 110M, and then the light emitting devices 120 may be formed on the pixel circuit such that the light emitting devices 120 are electrically connected to the pixel circuit.

[0112] Meanwhile, when a second mother substrate 160M (see Figure 10 )(S41) is provided, a diffraction pattern layer 170 including a plurality of diffraction patterns 171 may be formed on the surface of the second mother substrate 160M (S43). Next, the second mother substrate 160M may be cut and divided to match the size of the first mother substrate 110M (S45). Wet cleaning and plasma cleaning may be performed on the divided second mother substrate 160M (S47). Printing and baking of a first sealant and printing of a second sealant may be continuously performed on the other surface of the second mother substrate 160M (the surface opposite to the surface on which the diffraction patterns 171 are formed) (S49).

[0113] Next, as shown in Figure 10 , a combined substrate structure may be formed by aligning and bonding the first mother substrate 110M and the second mother substrate 160M (S51), with the pixel layer formed on the first mother substrate 110M and the diffraction pattern layer 170 formed on the second mother substrate 160M. Curing of the first sealant and the second sealant may be performed on the combined substrate structure (S53).

[0114] Next, as shown in Figure 16As shown in [Figure], a sacrificial layer 182 (S54) covering the diffraction pattern layer 170 can be formed on the second mother substrate 160M of the combined substrate structure 100M. The sacrificial layer 182 can be used as a protective member for protecting the diffraction pattern 171 in subsequent processes. The sacrificial layer 182 can be formed by printing, coating, or depositing a metal material, an organic material, or an inorganic material on the diffraction pattern layer 170. Optical processes, sputtering processes, etc. can be used for deposition. Methods such as screen printing, inkjet printing, dot printing, dip coating, spray coating, spin coating, etc. can be used for printing or coating. In Figure 15 the embodiment of [Figure], when the sacrificial layer 182 is formed after combination, an organic material or an inorganic material processed at a low temperature can be used as the sacrificial layer 182.

[0115] As Figure 17 shown in [Figure], a protective film 190 can be attached on top of the sacrificial layer 182 on the second mother substrate 160M of the combined substrate structure 100M through a lamination operation (S55), and a thinning operation (S57) can be performed on the first mother substrate 110M of the combined substrate structure 100M by using a physical / chemical process such as etching. After performing the thinning operation on the first mother substrate 110M, a peeling operation can be performed to remove the protective film 190 above the second mother substrate 160M (S59). Next, as Figure 18 shown in [Figure], the combined substrate structure 100M with the sacrificial layer 182 attached can be cleaned (S61).

[0116] Next, as Figure 19 shown in [Figure], a protective layer 101 can be formed on the first mother substrate 110M by using a screen printing machine (S63), and a thermal curing operation (S65) can be performed on the protective layer 101. The combined substrate structure 100M can be installed on the platform 100 such that the sacrificial layer 182 faces the platform 100, and the protective layer 101 can be formed on the first mother substrate 110M by using a screen printing machine.

[0117] As Figure 20 shown in [Figure], the sacrificial layer 182 of the combined substrate structure 100M can be removed (S66b). The sacrificial layer 182 can be removed by a separation process, an etching process, a peeling process, etc., and there is no particular limitation on the process for removing the sacrificial layer 182.

[0118] Figures 17 to 19 The embodiments shown in [Figure] can be similarly applied to Figure 11 the embodiments shown in [Figure]. For example, similar to Figure 17 the embodiment of [Figure], a protective film 190 can be attached on top of the sacrificial layer 180 on the second mother substrate 160M through a lamination operation (S55), and a thinning operation (S57) can be performed on the first mother substrate 110M. Similar to Figure 18In an embodiment, the protective film 190 over the second mother substrate 160M may be removed (S59), and the second mother substrate 160M may be cleaned. Next, similar to Figure 19 , a protective layer 101 may be formed on the first mother substrate 110M by using a screen printing machine (S63), and a thermal curing operation may be performed on the protective layer 101 (S65).

[0119] Returning to reference Figure 15 , the bonded substrate structure 100M from which the sacrificial layer 182 has been removed may be cut into a plurality of unit substrate structures 10' (see Figure 13A )(S67). Each unit substrate structure 10' may include a substrate 110 on which a light-emitting device 120 is disposed and an encapsulation layer 160 on which a diffraction pattern 171 is disposed.

[0120] A first polishing process (S69) and a second polishing process (S73) may be performed on each unit substrate structure 10'. To enhance the encapsulation function of the unit substrate structure 10', a strengthening sealing operation (S71) may be performed between the first polishing process and the second polishing process.

[0121] Next, defective products are selected by performing multiple inspection operations on the unit substrate structures 10' (S75), and those unit substrate structures 10' that pass the inspection may be encapsulated (S77) as the display device 10 as shown in Figure 1 .

[0122] Figure 15 The embodiment shown in is an example in which the sacrificial layer 182 is removed before the cutting operation (S67). According to some example embodiments, as shown in Figure 21 , the sacrificial layer 182 may be removed (S74b) after the cutting operation (S67). In a state where the sacrificial layer 182 is attached to the bonded substrate structure 100M, the bonded substrate structure 100M may be cut along a virtual cutting line CL and divided into a plurality of unit substrate structures 10'. A first polishing process (S69), a strengthening sealing operation (S71), and a second polishing process (S73) may be continuously performed on each unit substrate structure 10' to which the sacrificial layer 182 is attached.

[0123] Figure 22 is a schematic diagram showing a process of manufacturing the display device 10 according to an embodiment. Figure 23 is a diagram showing the display device 10 formed according to the process shown in Figure 22 .

[0124] Figure 22 The process of manufacturing the display device of is the same as that of Figure 9The difference in the process shown is that a coating operation (S66c) and a cleaning process (S74c) are added. Hereinafter, some details described above with reference to Figure 9 are omitted.

[0125] With reference to Figure 22 , when providing the first mother substrate 110M (see Figure 10 )(S31), a pixel layer including the light-emitting device 120 can be formed on the first mother substrate 110M (S33). First, a pixel circuit can be formed on the first mother substrate 110M, and then the light-emitting device 120 can be formed on the pixel circuit such that the light-emitting device 120 is electrically connected to the pixel circuit.

[0126] Meanwhile, when providing the second mother substrate 160M (see Figure 10 )(S41), a diffraction pattern layer 170 including the diffraction pattern 171 can be formed on the surface of the second mother substrate 160M (S43). Next, the second mother substrate 160M can be cut and divided to match the size of the first mother substrate 110M (S45). Wet cleaning and plasma cleaning can be performed on the second mother substrate 160M (S47). Printing and baking of the first sealant and printing of the second sealant can be continuously performed on the other surface of the cleaned second mother substrate 160M (the surface opposite to the surface on which the diffraction pattern 171 is formed) (S49).

[0127] Next, as shown in Figure 10 , a combined substrate structure can be formed by aligning and bonding the first mother substrate 110M and the second mother substrate 160M (S51), with the pixel layer formed on the first mother substrate 110M and the diffraction pattern layer 170 formed on the second mother substrate 160M. Curing of the first sealant and the second sealant can be performed on the combined substrate structure (S53).

[0128] Next, a protective film can be attached on top of the diffraction pattern layer 170 of the second mother substrate 160M by a lamination operation (S55), and a thinning operation according to a physical / chemical treatment such as etching can be performed on the first mother substrate 110M (S57). After performing the thinning operation on the first mother substrate 110M, a peeling operation can be performed to remove the protective film above the second mother substrate 160M (S59). After the peeling operation, the combined substrate structure can be cleaned (S61). Next, a protective layer can be formed on the first mother substrate 110M by using a screen printer (S63), and a thermal curing operation can be performed on the protective layer (S65).

[0129] Next, a coating layer 190 may be formed on the diffraction pattern layer 170 of the second mother substrate 160M (S66c). The coating layer 190 may be a functional layer such as an anti-fingerprint (AF) layer. The coating layer 190 may include a waterproof material and an oil-proof material. The coating layer 190 may include a coating material that includes a hydrophobic component and an oleophobic component to prevent fingerprints from adhering to the surface of the diffraction pattern layer 170 or to prevent stains and scratches thereon. The coating layer 190 including a scratch-resistant component and a fingerprint-resistant component may be formed on the diffraction pattern layer 170 by printing, coating, or depositing a waterproof / oil-proof material mainly including fluorine and hardening the waterproof / oil-proof material at a low temperature. A light process, a sputtering process, etc. may be used for deposition. Methods such as a screen printing method, an inkjet printing method, a dot printing method, a dip coating method, a spray coating method, a spin coating method, etc. may be used for printing or coating. The coating layer 190 may have a thickness that is unlikely to affect the characteristics of the finally manufactured display device even when the coating layer 190 is retained. The coating layer 190 may have a thickness of about 100 nm.

[0130] The combined substrate structure 100M with the coating layer 190 attached may be cut into a plurality of unit substrate structures 10' (see Figure 13A )(S67). Each unit substrate structure 10' may include a substrate 110 on which a light-emitting device 120 is disposed and a package layer 160 on which a diffraction pattern 171 is disposed.

[0131] A first polishing process (S69) and a second polishing process (S73) may be performed on each unit substrate structure 10'. To enhance the encapsulation function of the unit substrate structure 10', a strengthening sealing operation (S71) may be performed between the first polishing process and the second polishing process.

[0132] Next, foreign substances attached to the coating layer 190 may be removed by cleaning the unit substrate structure 10' (S74c). At this time, the coating layer 190 is not removed and remains. After cleaning, defective products are selected by performing multiple inspection operations on the unit substrate structure 10' (S75), and those unit substrate structures 10' that pass the inspection may be encapsulated (S77) as the display device 10 as shown in Figure 1 .

[0133] Figure 22 The embodiment shown in Figure 23 is an example in which the coating layer 190 formed before the cutting operation (S67) remains without being removed. As shown in

[0134] Figure 24 is a schematic diagram showing a process of manufacturing the display device 10 according to some example embodiments.

[0135] Figure 24 The embodiments shown are those in which Figure 14 the sacrificial layer formation operation and the sacrificial layer removal operation of the embodiment shown in Figure 22 are combined with the coating layer formation operation and the coating layer cleaning operation of the embodiment shown in. Referring to Figure 24 , first, after forming the diffraction pattern layer 170 (S43) and before the combining operation (S51), a sacrificial layer formation operation (S44) can be performed on the diffraction pattern layer 170, and a sacrificial layer removal operation (S66a) can be performed before the cutting operation (S67). Next, a coating layer formation operation (S66d) can be performed after the sacrificial layer removal operation (S66a), and a coating layer cleaning operation (S74d) can be performed after the first polishing process (S69), the enhanced sealing operation (S71), and the second polishing process (S73).

[0136] Figure 25 is a schematic diagram showing a process of manufacturing the display device 10 according to some example embodiments.

[0137] Figure 25 The embodiments shown are those in which Figure 15 the sacrificial layer formation operation and the sacrificial layer removal operation in the embodiment shown in Figure 22 are combined with the coating layer formation operation and the coating layer cleaning operation in the embodiment shown in. Referring to Figure 25 , first, after the combining process (S51), a sacrificial layer formation operation (S54) can be performed on top of the diffraction pattern layer 170, and a sacrificial layer removal process (S66b) can be performed before the cutting operation (S67). Subsequently, a coating layer formation operation (S66e) can be performed after the sacrificial layer removal operation (S66b), and a coating layer cleaning operation (S74e) can be performed after the first polishing process (S69), the enhanced sealing operation (S71), and the second polishing process (S73).

[0138] The process of manufacturing a display device according to an embodiment is described in a descriptive sense, and some operations may be omitted or added according to the components having various functions included in the display device. The embodiments can be applied to a method of manufacturing a display device in which, after an operation of forming a diffraction pattern on a package layer, at least one operation affecting the diffraction pattern is performed.

[0139] According to an embodiment of the display device, by reducing foreign substances generated in the process, product defects can be reduced and the yield can be improved.

[0140] According to some example embodiments, a display device in which an effective emission area ratio is increased may be provided. The effects of the embodiments are not limited to the above-written description, and various effects are further included in the specification.

[0141] It should be understood that the embodiments described herein should be considered only in a descriptive sense and not for purposes of limitation. The description of features or aspects within each embodiment should be considered applicable to other similar features or aspects in other embodiments.

[0142] Although one or more embodiments have been described with reference to the drawings, those of ordinary skill in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope defined by the claims and their equivalents.

Claims

1. A method of manufacturing a display device, the method comprising: Providing a first mother substrate; Forming a pixel layer including light-emitting devices on the first mother substrate; Providing a second mother substrate; Forming a diffraction pattern layer on the second mother substrate, the diffraction pattern layer being configured to diffract light emitted from the light-emitting devices; Forming a combined substrate structure by bonding the first mother substrate and the second mother substrate, the pixel layer being formed on the first mother substrate, and the diffraction pattern layer being formed on a surface of the second mother substrate opposite to the surface bonded to the first mother substrate; And Forming a plurality of unit substrate structures each including a first substrate and a second substrate by cutting the combined substrate structure, the pixel layer being formed on the first substrate, and the diffraction pattern layer being formed on the second substrate, wherein the method further comprises: forming a protection member on the diffraction pattern layer to prevent foreign substances from adsorbing on the diffraction pattern layer; and Removing the foreign substances on the diffraction pattern layer.

2. The method according to claim 1, wherein, The step of forming the protection member includes forming a sacrificial layer on the diffraction pattern layer, and The step of removing the foreign substances includes removing the sacrificial layer.

3. The method according to claim 1, wherein The step of forming the protection member includes forming a coating layer above the diffraction pattern layer, and The step of removing the foreign substances includes cleaning the coating layer.

4. The method according to claim 1, wherein The step of forming the protection member includes forming a sacrificial layer covering the diffraction pattern layer between the step of forming the diffraction pattern layer and the step of forming the combined substrate structure; And The step of removing the foreign substances includes removing the sacrificial layer after the step of forming the plurality of unit substrate structures.

5. The method according to claim 1, wherein, The step of forming the protection member includes forming a sacrificial layer covering the diffraction pattern layer between the step of forming the diffraction pattern layer and the step of forming the combined substrate structure; And The step of removing the foreign substances includes removing the sacrificial layer between the step of forming the combined substrate structure and the step of forming the plurality of unit substrate structures.

6. The method according to claim 1, wherein, The step of forming the protection member includes forming a sacrificial layer covering the diffraction pattern layer after the step of forming the combined substrate structure, and The step of removing the foreign substances includes removing the sacrificial layer between the step of forming the sacrificial layer and the step of forming the plurality of unit substrate structures.

7. The method according to claim 1, wherein The step of forming the protection member includes forming a sacrificial layer covering the diffraction pattern layer between the step of forming the combined substrate structure and the step of forming the plurality of unit substrate structures, and The step of removing the foreign substances includes removing the sacrificial layer after the step of forming the plurality of unit substrate structures.

8. The method according to claim 1, wherein The step of forming the protection member includes forming a coating layer covering the diffraction pattern layer between the step of forming the combined substrate structure and the step of forming the plurality of unit substrate structures, and The step of removing the foreign substances includes cleaning the coating layer after the step of forming the plurality of unit substrate structures.

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