Transparent display device

Abstract

A transparent display device is provided, which can improve the visibility of an image of external light. The transparent display device includes: a substrate, the substrate includes a plurality of pixels, each of the plurality of pixels has a light emitting area and a transmission area; and a reproduction plate, the reproduction plate is arranged parallel to the substrate, wherein the reproduction plate includes a plurality of reproduction parts at least partially overlapping the transmission area.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Korean Patent Application No. 10-2021-0177812, filed on December 13, 2021, which is hereby incorporated by reference as if fully set forth herein. Technical Field

[0003] The present disclosure relates to a transparent display device. Background Art

[0004] With the development of the information age, the demand for display devices for displaying images has increased in various forms. Therefore, various types of display devices such as liquid crystal display (LCD) devices, plasma display panel (PDP) devices, organic light emitting display (OLED) devices, and quantum dot light emitting display (QLED) devices have been used recently.

[0005] Recently, research on a transparent display device in which a user can view an object or image located on the opposite side through a display device is actively being conducted. The transparent display device includes a display unit on which an image is displayed and a non-display unit including a frame area, wherein the display unit may include a transmission area capable of transmitting external light and a non-transmission area having a light-emitting area.

[0006] In addition, a user located on the front surface of the transparent display device can view an image through the light emitted from the light-emitting area of ​​the transparent display device. However, when external light is irradiated from the rear surface of the transparent display device to its front surface, since the external light passes through the transmission area, the user located on the front surface has a problem that the visibility of the image is deteriorated due to the external light. Therefore, although methods such as extended black film are designed to prevent external light from being incident on the transparent display device, it takes a considerable amount of time for the external light to be blocked and it is not possible to block the external light 100%, so there is a problem that the effect of improving the visibility of the image is not obvious. Summary of the invention

[0007] The present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide a transparent display device that can improve visibility of an image to external light by improving brightness.

[0008] In addition to the above-mentioned objects of the present disclosure, other objects and features of the present disclosure will be clearly understood by those skilled in the art from the following description of the present disclosure.

[0009] According to one aspect of the present disclosure, the above and other objects can be achieved by providing a transparent display device, which includes: a substrate, the substrate including a plurality of pixels, each of the plurality of pixels having a light-emitting area and a transmission area; and a reproduction plate, the reproduction plate is arranged in parallel with the substrate, wherein the reproduction plate includes a plurality of reproduction parts that at least partially overlap with the transmission area.

[0010] According to another aspect of the present disclosure, the above and other objects can be achieved by providing a transparent display device, which includes: a substrate, the substrate including a plurality of pixels, each of the plurality of pixels having a light-emitting area and a transmission area; and a reproduction plate, the reproduction plate reflecting light emitted from the light-emitting area and incident through the transmission area, wherein the reproduction plate includes: a plurality of first reproduction members that reflect red light incident through the transmission area; a plurality of second reproduction members that reflect green light incident through the transmission area; and a plurality of third reproduction members that reflect blue light incident through the transmission area, and the plurality of first reproduction members, the plurality of second reproduction members, and the plurality of third reproduction members are alternately arranged. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The above and other objects, features and other advantages of the present disclosure will be more clearly understood through the following detailed description in conjunction with the accompanying drawings, in which:

[0012] Figure 1 is a perspective view illustrating a transparent display device according to one embodiment of the present disclosure;

[0013] Figure 2 It is a graphic Figure 1 Flat photographs of multiple reproduced parts of the

[0014] Figure 3 It is a graphic Figure 2 A schematic enlarged perspective view of region A;

[0015] Figure 4 is along Figure 1 A schematic cross-sectional view taken along line II' shown in FIG. 1 , illustrating the optical path of the first reproducing member;

[0016] Figure 5 It is a graphic Figure 4 A schematic perspective view of a reproduction plate of

[0017] Figure 6 It is a graphic Figure 4 a schematic cross-sectional view of a first sub-reproducing member, a second sub-reproducing member and a third sub-reproducing member of a first reproducing member;

[0018] Figure 7It is illustrated by setting Figure 4 A schematic cross-sectional view of the diffraction of the reproduction member in the third reproduction area and the fourth reproduction area of ​​;

[0019] Figure 8 It is a graphic Figure 4 A schematic diagram of the optical paths of the first reproduction area and the fourth reproduction area;

[0020] Fig. 9 is along Figure 1 A schematic cross-sectional view taken along line II-II' shown in FIG. 1 , which illustrates an optical path of a second reproducing member; and

[0021] Fig.10 is along Figure 1 1 is a schematic cross-sectional view taken along line III-III' shown in FIG. 1 , which illustrates the optical path of the third reproducing member. DETAILED DESCRIPTION

[0022] Reference will now be made in detail to exemplary embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.

[0023] Advantages and features of the present disclosure and methods of achieving the same will be clarified through the following embodiments described with reference to the accompanying drawings.

[0024] However, the present disclosure may be implemented in different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided to make the present disclosure comprehensive and complete and to fully convey the scope of the present disclosure to those skilled in the art. Furthermore, the present disclosure is limited only by the scope of the claims.

[0025] The shapes, sizes, proportions, angles, and quantities disclosed in the accompanying drawings for the purpose of describing the embodiments of the present disclosure are merely examples, and the present disclosure is not limited to the details shown. Similar reference numerals in the accompanying drawings represent similar elements throughout. In the following description, when it is determined that a detailed description of the related known technology would unnecessarily obscure the key points of the present disclosure, the detailed description will be omitted.

[0026] Where “including,” “having,” and “comprising” are used in the description in the present application, other parts may be added unless “only” is used. Unless otherwise stated, terms in the singular form may include plural forms.

[0027] When interpreting an element, although not explicitly described, the element should be interpreted as including the error range.

[0028] When describing a positional relationship, for example, when the positional relationship between two parts is described as “on,” “above,” “below,” and “after,” one or more other parts may be set between the two parts, unless “just” or “directly” is used.

[0029] When describing a time relationship, for example, when a time sequence is described as "after," "subsequently," "next," and "before," discontinuity may be included unless "directly" or "directly" is used.

[0030] It will be understood that although the terms "first", "second", etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are merely used to distinguish elements from each other. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of the present disclosure.

[0031] The “X-axis direction”, “Y-axis direction” and “Z-axis direction” should not be interpreted as only geometric relationships of being perpendicular to each other, but may have broader directivities within the range in which the elements of the present disclosure functionally act.

[0032] The term "at least one" should be understood to include any and all combinations of one or more of the relevant listed items. For example, the meaning of "at least one of a first item, a second item, and a third item" refers to the combination of all items selected from two or more items of the first item, the second item, and the third item, as well as the first item, the second item, or the third item.

[0033] Those skilled in the art will fully appreciate that the features of the various embodiments of the present disclosure may be combined or combined with each other in part or in whole, and may interoperate and drive each other in various ways in technology. The embodiments of the present disclosure may be implemented independently of each other, or implemented together in a mutually dependent relationship.

[0034] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0035] Figure 1 is a perspective view illustrating a transparent display device according to one embodiment of the present disclosure, Figure 2 It is a graphic Figure 1 A flat photograph of multiple reproduced parts of Figure 3 It is a graphic Figure 2 A schematic enlarged perspective view of area A, Figure 4 is along Figure 1 , which illustrates the optical path of the first reproducing member, Figure 5 It is a graphic Figure 4A schematic perspective view of a reproduction plate of Figure 6 It is a graphic Figure 4 a schematic cross-sectional view of a first sub-reproducing member, a second sub-reproducing member and a third sub-reproducing member of a first reproducing member of FIG. Figure 7 It is illustrated by setting Figure 4 Schematic cross-sectional view of the diffraction of the reproduction member in the third reproduction area and the fourth reproduction area of ​​, Figure 8 It is a graphic Figure 4 Schematic diagram of the light paths of the first reproduction area and the fourth reproduction area.

[0036] Hereinafter, the following description will be based on the transparent display device 100 according to one embodiment of the present disclosure being an organic light-emitting display device, but is not limited thereto. That is, the transparent display device according to one embodiment of the present disclosure may be implemented as any one of a liquid crystal display device, a field emission display device, a quantum dot light-emitting diode device, an electrophoretic display device, and an organic light-emitting display device.

[0037] Reference Figures 1 to 8 According to one embodiment of the present disclosure, a transparent display device 100 may include: a display panel having a gate driver GD and a transmission area TA; a source driver integrated circuit (hereinafter referred to as "IC") 120; a flexible film 130; a circuit board 140; a timing controller 150; and a reproduction board 200 arranged in parallel with the display panel.

[0038] The display panel may include a substrate 110 and an opposing substrate 110' (eg, Figure 4 ).

[0039] The substrate 110 may include a thin film transistor and may be a transistor array substrate, a lower substrate or a first substrate. The substrate 110 may be a transparent glass substrate or a transparent plastic substrate. For example, the substrate 110 may be a transparent glass substrate. Hereinafter, the substrate 110 will be defined as a first substrate.

[0040] The opposite substrate 110' may be bonded to the first substrate 110. For example, the opposite substrate 110' may have a size smaller than that of the first substrate 110, and may be bonded to the remaining portion except for the pad region PP of the first substrate 110. The opposite substrate 110' may be an upper substrate, a second substrate, or a package substrate. The opposite substrate 110' may be bonded to the first surface of the first substrate 110 by a substrate bonding process using an adhesive member (or a transparent adhesive). Hereinafter, the opposite substrate 110' will be defined as a second substrate.

[0041] The first substrate 110 according to an example may include a display unit AA and a non-display unit IA.

[0042] The display unit AA is an area where an image is displayed, and may be a pixel array area, an effective area, a pixel array unit, a display area, or a screen. For example, the display unit AA may be disposed at a central portion of the display panel DP.

[0043] The display unit AA according to one example may include a gate line, a data line, a pixel driving power line, and a plurality of pixels P. Each of the plurality of pixels P may be defined by a gate line and a data line, and may include a plurality of sub-pixels SP including a light emitting area EA for emitting light and a transmission area TA disposed adjacent to some or all of the plurality of sub-pixels SP. The transmission area TA is an area disposed to allow light to pass through the front and rear surfaces of the display panel. Therefore, a user located in the front surface direction of the display panel can view an image or background located in the rear surface direction of the display panel through the transmission area TA.

[0044] However, when external light is irradiated from the rear surface of the display panel, the external light may be transmitted to the front surface of the display panel through the transmission area, so that the visibility of the image output from the display unit AA to the user located in the direction of the front surface of the display panel may be deteriorated. Therefore, the transparent display device 100 according to one embodiment of the present disclosure may further include a reproduction plate 200 on the rear surface of the display panel (or substrate 110), thereby shielding the external light incident on the front surface of the display panel from the rear surface of the display panel to improve the visibility of the image.

[0045] The reproduction plate 200 according to one example may include a plurality of reproduction parts 210 at least partially overlapping with the transmission area TA. Each of the plurality of reproduction parts 210 may be arranged in a cylindrical shape. The plurality of reproduction parts 210 are spaced apart from each other by a predetermined distance. The plurality of reproduction parts 210 may reflect light emitted from the light emitting area EA and incident through the transmission area TA in a first path (e.g., RL1) to a second path (e.g., RL1-1) opposite to the first path RL1. This may be achieved by a difference in refractive index between the plurality of reproduction parts 210, a base substrate 220 positioned adjacent to the plurality of reproduction parts 210, and a cover layer 230 covering the base substrate 220 and the plurality of reproduction parts 210. In addition, light incident to the plurality of reproduction parts 210 through the transmission area TA is diffracted by the adjacent reproduction parts 210, so that the path of light reflected by constructive and destructive interference may be determined. As a result, the plurality of reproduction parts 210 can reflect the image light emitted from the light emitting area EA and incident through the transmission area TA in the first path to the position where the light was emitted through the second path by the difference in the refractive index of the base substrate 220 and the cover layer 230 and the constructive and destructive interference generated by diffraction. This will be described in detail later.

[0046] Each of the plurality of sub-pixels SP may be defined as a minimum unit area that actually emits light.

[0047] According to an example, three sub-pixels disposed adjacent to each other among the plurality of sub-pixels SP or three sub-pixels disposed adjacent to each other along the length direction of the data line (or gate line), and one transmission area TA constitute one unit pixel. One unit pixel may include, but is not limited to, at least one red sub-pixel, at least one green sub-pixel, at least one blue sub-pixel, and at least one transmission area TA. Each of the three sub-pixels SP may be disposed adjacent to one transmission area TA.

[0048] According to another example, at least four sub-pixels disposed adjacent to each other among the plurality of sub-pixels SP or four sub-pixels disposed adjacent to each other along the length direction of the data line (or gate line), and one transmission area TA constitute one unit pixel. One unit pixel may include, but is not limited to, a red sub-pixel, a green sub-pixel, a blue sub-pixel, a white sub-pixel, and a transmission area TA. Each of the four sub-pixels SP may be disposed adjacent to one transmission area TA.

[0049] Each of the plurality of sub-pixels SP includes a thin film transistor and a light emitting portion connected to the thin film transistor. The light emitting portion may include a light emitting element layer (or an organic light emitting layer) sandwiched between a pixel electrode and a common electrode.

[0050] The light emitting element layers respectively arranged in the plurality of sub-pixels SP may individually emit light of different colors from each other, or may collectively emit white light. According to an example, when the light emitting element layers of the plurality of sub-pixels SP collectively emit white light, each of the red sub-pixel, the green sub-pixel, and the blue sub-pixel may include a color filter (or wavelength conversion member) for converting the white light into light of its respective different colors. In this case, the white sub-pixel according to an example may not include a color filter. At least a portion of the white sub-pixel according to another example may include the same color filter as any one of the red sub-pixel, the green sub-pixel, and the blue sub-pixel.

[0051] When a gate signal is input from a gate line by using a thin film transistor, each sub-pixel SP provides a predetermined current to the organic light emitting element according to a data voltage of the data line. To this end, the light emitting portion of each sub-pixel can emit light with a predetermined brightness according to the predetermined current. The portion from which light is emitted from each sub-pixel may be a light emitting area EA. Therefore, the light emitting area EA of each sub-pixel may be disposed adjacent to the transmission area TA. This will be referred to later. Figure 4 The structure of each sub-pixel SP is described.

[0052] The non-display unit IA may be an area where an image is not displayed, and may be a peripheral circuit area, a signal supply area, a non-effective area, or a frame area. The non-display unit IA may be arranged around the display unit AA. That is, the non-display unit IA may be arranged to surround the display unit AA. The non-display unit IA may include a plurality of pad portions PP connected to a plurality of pixels P arranged in the display unit AA. The plurality of pad portions PP may be spaced apart from each other along the first axis direction X. Each of the plurality of pad portions may include a plurality of data pads, at least one pixel driving power pad, and a plurality of common power pads.

[0053] The gate driver GD provides a gate signal to the gate line according to the gate control signal input from the timing controller 150. Figure 1 In the gate-in-panel (GIP) method shown in , the gate driver GD may be formed on one side of the display unit AA of the display panel or on the non-display unit IA outside the two sides of the display unit AA. Alternatively, the gate driver GD may be manufactured as a driver chip that is encapsulated in a flexible film and attached to the non-display unit IA outside one side or both sides of the display unit AA of the display panel by a tape automated bonding (TAB) method. The gate driver GD may include a plurality of gate drive circuits (or GIP circuit portions).

[0054] The source driver IC 120 receives digital video data and a source control signal from the timing controller 150. The source driver IC 120 converts the digital video data into an analog data voltage according to the source control signal and supplies the analog data voltage to the data line. When the source driver IC 120 is manufactured as a driver chip, the source driver IC 120 may be packaged in the flexible film 130 in a chip on film (COF) method or a chip on plastic (COP) method.

[0055] A pad such as a data pad may be formed in the non-display unit 1A of the display panel. A line connecting the pad with the source driver IC 120 and a line connecting the pad with a line of the circuit board 140 may be formed in the flexible film 130. The flexible film 130 may be attached to the pad by using an anisotropic conductive film so that the pad may be connected to the line of the flexible film 130.

[0056] The circuit board 140 may be attached to the flexible film 130. A plurality of circuits implemented as a driving chip may be packaged in the circuit board 140. For example, the timing controller 150 may be packaged in the circuit board 140. The circuit board 140 may be a printed circuit board or a flexible printed circuit board.

[0057] The timing controller 150 receives digital video data and a timing signal from an external system board through a cable of the circuit board 140. The timing controller 150 generates a gate control signal for controlling the operation timing of the gate driver GD and a source control signal for controlling the source driver IC 120 based on the timing signal. The timing controller 150 provides the gate control signal to the gate driver GD and provides the source control signal to the source driver IC 120.

[0058] Reference Figure 1 , the transmission area TA may be disposed adjacent to the plurality of sub-pixels SP, and may be included in one pixel P. Since the plurality of pixels P are disposed in the display unit AA, the plurality of transmission areas TA may be disposed in the display unit AA.

[0059] The display unit AA may include a transmission area TA and a non-transmission area other than the transmission area TA. The transmission area TA is an area through which most of the light incident from the outside passes, and the non-transmission area is an area through which most of the light incident from the outside does not transmit. For example, the transmission area TA may have a light transmittance of α%, for example, greater than 90%, and the non-transmission area may have a light transmittance of β%, for example, less than 50%. At this time, α is a value greater than β. Due to the transmission area TA, the user can see an object or background located on the rear surface of the display panel. Figure 1 As shown in FIG. 1 , in order to improve the transmittance of an object or a background located on the rear surface of the display panel, the transmissive area TA may not be provided with the planarization layer 113 and the bank 115 .

[0060] In addition, when a gate signal from a gate line is input using a thin film transistor, each sub-pixel SP provides a predetermined current to the organic light emitting element according to a data voltage of the data line. Therefore, the light emitting portion of each sub-pixel SP can emit light with a predetermined brightness according to the predetermined current.

[0061] Reference Figure 1 and Figure 4 According to an example, each of the first to third sub-pixels SP1, SP2, and SP3 may include a circuit element layer 111 disposed on the upper surface of the buffer layer BL, a planarization layer 113 disposed on the circuit element layer 111, a pixel electrode 114 disposed on the planarization layer 113, a bank 115, an organic light emitting layer 116, a common electrode 117, and an encapsulation layer 118, and the circuit element layer 111 includes a gate insulating layer 111a, an interlayer insulating layer 111b, a passivation layer 111c, and a thin film transistor 112. The pixel electrode 114, the organic light emitting layer 116, and the common electrode 117 may be included in the light emitting element.

[0062] The buffer layer BL according to one example is disposed on the substrate 110 to prevent moisture from penetrating into the thin film transistor 112. The buffer layer BL may be formed between the substrate 110 and the circuit element layer 111 (or the gate insulating layer 111a) to protect the thin film transistor 112. The buffer layer BL may be entirely disposed on one surface (or the front surface) of the substrate 110. The buffer layer BL may be used to prevent the material included in the substrate 110 from diffusing into the transistor layer during the high temperature process of the manufacturing process of the thin film transistor.

[0063] The circuit element layer 111 may include a gate insulating layer 111a, an interlayer insulating layer 111b, a passivation layer 111c, and a thin film transistor 112. The gate insulating layer 111a, the interlayer insulating layer 111b, and the passivation layer 111c may be made of an inorganic material.

[0064] The thin film transistor 112 according to an example may include an active layer 112 a , a gate electrode 112 b , a source electrode 112 c , and a drain electrode 112 d .

[0065] The active layer 112a may include a channel region, a drain region, and a source region formed in a thin film transistor region of a circuit region of the pixel P. The drain region and the source region may be spaced apart from each other with the channel region interposed therebetween.

[0066] The active layer 112 a may be formed of a semiconductor material based on any one of amorphous silicon, polysilicon, oxide, and an organic material.

[0067] The gate insulating layer 111a may be formed over the channel region of the active layer 112a. As an example, the gate insulating layer 111a may be formed in an island shape only over the channel region of the active layer 112a, or may be formed over the entire front surface of the first substrate 110 or the buffer layer BL including the active layer 112a.

[0068] The gate electrode 112 b may be formed on the gate insulating layer 111 a to overlap the channel region of the active layer 112 a .

[0069] The interlayer insulating layer 111b may be formed over the gate electrode 112b and the drain region and the source region of the active layer 112a. The interlayer insulating layer 111b may be formed in the circuit region and the entire light emitting region in which light is emitted to the pixel P. For example, the interlayer insulating layer 111b may be made of an inorganic material, but is not necessarily limited thereto.

[0070] The source electrode 112 c may be electrically connected to the source region of the active layer 112 a through a source contact hole provided in the interlayer insulating layer 111 b overlapping the source region of the active layer 112 a .

[0071] The drain electrode 112 d may be electrically connected to the drain region of the active layer 112 a through a drain contact hole provided in the interlayer insulating layer 111 b overlapping the drain region of the active layer 112 a .

[0072] The drain electrode 112d and the source electrode 112c may be made of the same metal material. For example, each of the drain electrode 112d and the source electrode 112c may be made of a single metal layer, a single alloy layer, or a multilayer of two or more layers that is the same as or different from the gate electrode described above.

[0073] In addition, the circuit region may further include first and second switching thin film transistors provided together with the thin film transistor 112, and a capacitor. Since each of the first and second switching thin film transistors is provided above the circuit region of the pixel P and thus has the same structure as that of the thin film transistor 112, a description thereof will be omitted. A capacitor (not shown) may be provided in an overlapping region between a gate electrode 112b and a source electrode 112c of the thin film transistor 112, which overlap each other with an interlayer insulating layer 111b interposed therebetween.

[0074] In addition, in order to prevent the threshold voltage of the thin film transistor disposed in the pixel area from being shifted due to light, the display panel or the first substrate 110 may further include a light shielding layer (not shown) disposed below the active layer 112a of at least one of the thin film transistor 112, the first and second switching thin film transistors. The light shielding layer may be disposed between the substrate 110 and the active layer 112a to shield light incident on the active layer 112a through the substrate 110, thereby reducing or minimizing the change in the threshold voltage of the transistor due to external light.

[0075] The passivation layer 111c may be disposed on the substrate 110 to cover the pixel region where the pixel P is disposed. The passivation layer 111c covers the drain electrode 112d and the source electrode 112c of the thin film transistor 112 and the interlayer insulating layer 111b. The passivation layer 111c may be entirely formed in the circuit region and the light emitting region.

[0076] The planarization layer 113 may be formed on the substrate 110 to cover the passivation layer 111c. The planarization layer 113 may be entirely formed in the circuit region and the light emitting region.

[0077] The planarization layer 113 according to an example may be formed to be relatively thick, and thus may provide a flat surface over the display unit AA. For example, the planarization layer 113 may be made of an organic material such as photo acrylic, benzocyclobutene, polyimide, and fluororesin.

[0078] The planarization layer 113 according to one example may be formed to cover the circuit element layer 111 and the edge portion of the substrate 110 except for the transmission area TA. Therefore, the passivation layer 111c of the circuit element layer 111 disposed at the edge portion of the substrate 110 may be exposed without being covered by the planarization layer 113. In addition, since the planarization layer 113 is not disposed in the transmission area TA, transmittance may be improved.

[0079] The light emitting element layer may be disposed on the planarization layer 113. The light emitting element layer according to an example may include a pixel electrode 114, an organic light emitting layer 116, and a common electrode 117.

[0080] The pixel electrode 114 may be denoted as an anode electrode, a reflective electrode, a lower electrode, or a first electrode of the organic light emitting layer 116 .

[0081] The pixel electrode 114 may be disposed on a portion of the planarization layer 113 overlapping the light emitting area EA of each pixel. The pixel electrode 114 may be patterned into an island shape to be disposed in each pixel, and may be electrically connected to the source electrode 112c / drain electrode 112d of the thin film transistor (or driving TFT) 112 of the corresponding pixel circuit. One side of the pixel electrode 114 may extend onto the source electrode 112c / drain electrode 112d of the thin film transistor 112, and may be electrically connected to the source electrode 112c / drain electrode 112d of the thin film transistor 112 through a contact hole disposed in the planarization layer 113.

[0082] The pixel electrode 114 according to one example may include a metal material having a low work function and excellent reflection efficiency.

[0083] As an example, when the transparent display device 100 is set to the top emission mode, the pixel electrode 114 can be formed by a metal material with high reflectivity or a stacked structure of a metal material with high reflectivity and a transparent metal material. For example, the pixel electrode 114 can have a stacked structure of a lower electrode and an upper electrode. The lower electrode can be arranged between the planarization layer 113 and the upper electrode, and can have a binding force with the upper electrode greater than the binding force with the planarization layer. The lower electrode according to an example can be arranged in a stacked structure (ITO / MoTi / ITO) of MoTi and ITO to improve the binding force with the planarization layer 113. The upper electrode is arranged on the upper surface (or upper side) of the lower electrode, that is, between the lower electrode and the organic light-emitting layer 116, and can be set to a stacked structure (ITO / Ag / ITO) of Ag and ITO. The upper electrode can have a reflectivity of light reflected from the organic light-emitting layer 116 higher than the lower electrode.

[0084] like Figure 1 and Figure 4As shown in , since the pixel electrode 114 is provided in the display unit AA, the planarization layer 113 may be provided below the pixel electrode 114 in the display unit AA. The planarization layer 113 is provided to a predetermined thickness to cover the thin film transistor 112 for making the organic light emitting layer 116 emit light, so that the upper surface of the planarization layer 113 may be provided to be flat. Therefore, the pixel electrode 114 provided on the planarization layer 113 may be provided to be flat along the contour of the upper surface of the planarization layer 113.

[0085] The bank 115 may be disposed in a non-luminescent non-region and may be disposed to surround each of the luminescent regions EA of each of the plurality of sub-pixels. That is, the bank 115 may divide (or define) each luminescent region EA. The bank 115 may be formed to cover the edge of the pixel electrode 114, thereby dividing (or defining) the luminescent region EA of each of the plurality of sub-pixels.

[0086] The bank 115 may be formed to cover the edge of each pixel electrode 114 of each sub-pixel and expose a portion of each pixel electrode 114. Therefore, the bank 115 may prevent a short circuit from occurring between the pixel electrode 114 and the common electrode 117 located at the edge of the pixel electrode 114. The exposed portion of the pixel electrode 114 not covered by the bank 115 may be the emission area EA.

[0087] The bank 115 may be formed of an organic layer such as acrylic resin, epoxy resin, phenol resin, polyamide resin, and polyimide resin, but is not limited thereto.

[0088] The organic light emitting layer 116 is formed over the pixel electrode 114 and the bank 115. When a voltage is applied to the pixel electrode 114 and the common electrode 117, holes and electrons move to the organic light emitting layer 116, respectively, and are combined with each other in the organic light emitting layer 116 to emit light.

[0089] The organic light emitting layer 116 may be formed of a common layer disposed over the plurality of sub-pixels SP and the bank 115. In this case, the organic light emitting layer 116 may be disposed in a series structure in which a plurality of light emitting layers, such as a yellow-green light emitting layer and a blue light emitting layer, are stacked, and when an electric field is formed between the pixel electrode 114 and the common electrode 117, white light may be emitted.

[0090] A color filter (not shown) suitable for the color of the corresponding sub-pixel may be formed in each of the plurality of sub-pixels. For example, a red color filter may be provided in a red sub-pixel, a green color filter may be provided in a green sub-pixel, and a blue color filter may be provided in a blue sub-pixel. Since the organic light emitting layer 116 emits white light, a color filter may not be provided in a white sub-pixel.

[0091] The common electrode 117 is formed on the organic light emitting layer 116. The common electrode 117 may be a second electrode or a cathode electrode. The common electrode 117 may be a common layer formed in common in the sub-pixels. The common electrode 117 may be formed of a transparent metal material, a semi-transmissive metal material, or a metal material with high reflectivity.

[0092] When the transparent display device 100 is provided in a top emission mode, the common electrode 117 can be formed of a light-transmitting transparent conductive material (TCO) such as ITO and IZO, or a semi-transmitting conductive material such as magnesium (Mg), silver (Ag), or an alloy of magnesium (Mg) and silver (Ag).

[0093] The encapsulation layer 118 is formed on the common electrode 117. The encapsulation layer 118 serves to prevent oxygen or moisture from penetrating into the organic light emitting layer 116 and the common electrode 117. To this end, the encapsulation layer 118 may include at least one inorganic layer and at least one organic layer.

[0094] The encapsulation layer 118 according to an example may include a first inorganic layer 118a disposed on the common electrode 117 of the display unit AA, an organic layer 118b disposed on the first inorganic layer 118a, and a second inorganic layer 118c disposed on the organic layer 118b. The thickness of the organic layer 118b may be set to be sufficient to cover foreign matter (not shown) such as particles that may appear when forming a light-emitting element including the organic light-emitting layer 116.

[0095] The organic layer 118b according to an example may extend to a dam portion (not shown) provided in the non-display unit IA and the display unit AA. The first inorganic layer 118a and the second inorganic layer 118c may be provided to extend toward an end portion of the substrate 110 to cover the common electrode 117 provided to extend from the display unit AA to the non-display unit IA, and the dam portion provided in the non-display unit IA.

[0096] Reference Figure 4, the reproduction plate 200 may be disposed in parallel with the substrate 110. For example, at least a portion of the reproduction plate 200 may be disposed in parallel with the substrate 110 to overlap with the substrate 110 in the thickness direction of the substrate 110, that is, in the third axis direction Z. Therefore, the reproduction plate 200 may reflect the light emitted from the light emitting area EA, reflected at the interface between the organic layer 118b and the second inorganic layer 118c, and emitted to the rear surface of the substrate 110 through the transmission area TA, back to the transmission area TA. To this end, the reproduction plate 200 may include a plurality of reproduction portions 210 at least partially overlapping the transmission area TA. The light emitted from the light emitting area EA may be reflected at the boundary surface between the second inorganic layer 118c and the second substrate 110' or the boundary surface between the second substrate 110' and the external air, and then may be emitted toward the transmission area TA. The plurality of reproduction portions 210 may be disposed over the back surface of the substrate 110 to reflect the light of the light emitting area EA emitted toward the transmission area TA, that is, the image light toward the light path opposite to the light path of the incident light, and emit the light toward the front surface of the substrate 110.

[0097] Reference Figures 1 to 4 , the plurality of reproduction portions 210 may overlap at least a portion of the transmission area TA. For example, a portion of the plurality of reproduction portions 210 may overlap the transmission area TA, and the other portions of the plurality of reproduction portions 210 may overlap the sub-pixel SP and the embankment 115 located in the non-luminescent area in the third axis direction Z. The other portions of the plurality of reproduction portions 210 may overlap the luminescent area EA, but the present disclosure is not limited thereto. All of the plurality of reproduction portions 210 may be arranged to overlap only the transmission area TA. The second axis direction Y is perpendicular to each of the first axis direction X and the third axis direction Z, and may represent a vertical direction of the display panel.

[0098] The plurality of reproduction sections 210 may be arranged in the form of a circle or circular track. Figure 2 and Figure 3As shown in , a plurality of reproduction parts 210 may be provided in the form of a circle or a circular track. The circle may be provided at a position corresponding to the central portion of the transmissive area TA, and a plurality of circular tracks may be provided along a circumference having a diameter greater than that of the circle. For example, the first reproduction area RA1 may be formed in the form of a circle, and the first reproduction members 211 may be separated from each other within the circle. The second reproduction area RA2 may be formed in a circle (or a circular track) having a diameter greater than that of the first reproduction area RA1, and the second reproduction member 212 and the third reproduction member 213 may be separated from each other along the circle (or circular track) of the second reproduction area RA2. The third reproduction area RA3 may be formed in a circle (or a circular track) having a diameter greater than that of the second reproduction area RA2, and the first reproduction member 211, the second reproduction member 212, and the third reproduction member 213 may be separated from each other along the circle (or circular track) of the third reproduction area RA3. The first reproduction area RA1, the second reproduction area RA2, and the third reproduction area RA3 may be provided in the form of concentric circles having different diameters.

[0099] The transparent display device 100 according to one embodiment of the present disclosure includes a plurality of reproduction parts 210 in the form of a circle (or circular track), so that incident light emitted from the organic light emitting layer can be reflected by being focused at a light emitting position (or location). This can be similar to focusing light at the focal length of a concave mirror when light is irradiated to the concave mirror. However, the concave mirror is provided with a reflective surface having a curvature to reflect light, while the plurality of reproduction parts 210 described herein are provided to be flat, such as Figure 3 As shown in , and by adjusting the diameter and interval of each of the plurality of reproduction parts 210, the diffraction and refraction characteristics of light are used to reflect the light. In the transparent display device 100 according to one embodiment of the present disclosure, the plurality of reproduction parts 210 are arranged in the form of circles with different diameters and different intervals, so that the incident light with different wavelength ranges emitted from the organic light emitting layer can be reflected by focusing on the light emitting position (or location), such as Figure 4 Therefore, in the transparent display device 100 according to one embodiment of the present disclosure, light emitted toward the rear surface (or reproduction plate) through the transmission area may be reflected toward the front surface (or light emitting area), so that the brightness of the image may be improved.

[0100] Reference Figures 1 to 4, the transmission area TA may include a first transmission area TA1 as a central portion, a third transmission area TA3 as an edge portion, and a second transmission area TA2 between the first transmission area TA1 and the third transmission area TA3. The reproduction plate 200 may include a first reproduction area RA1 overlapping the first transmission area TA1 in the third axis direction Z, a second reproduction area RA2 overlapping the second transmission area TA2 in the third axis direction Z, and a third reproduction area RA3 overlapping the third transmission area TA3 in the third axis direction Z. The plurality of reproduction parts 210 may include a plurality of first reproduction members 211 for reflecting red light, a plurality of second reproduction members 212 for reflecting green light, and a plurality of third reproduction members 213 for reflecting blue light. Only a portion of the plurality of first reproduction members 211 may be disposed in the first reproduction area RA1. A portion of each of the plurality of second reproduction members 212 and the plurality of third reproduction members 213 may be disposed in the second reproduction area RA2. A portion of each of the plurality of first reproduction members 211, the plurality of second reproduction members 212, and the plurality of third reproduction members 213 may be disposed in the third reproduction area RA3.

[0101] like Figure 2 As shown in the right enlarged view of , a plurality of first sub-reproducing members 211a among the plurality of first reproducing members 211 may be disposed adjacent to each other at predetermined intervals in a circle (or first reproducing area RA1) corresponding to the first transmission area TA1. Figure 2 and Figure 3 , a cylindrical first reproduction member 211 having a predetermined diameter may be disposed as a circle with a predetermined interval in the first reproduction area RA1. A plurality of cylindrical second reproduction members 212 having a diameter different from that of the first reproduction member 211 may be disposed in the second reproduction area RA2. The second reproduction member 212 may be spaced apart from the first reproduction member 211 by a predetermined distance to surround the first reproduction member 211. That is, the plurality of first reproduction members 211 and the plurality of second reproduction members 212 may be alternately disposed.

[0102] Reference Figures 2 to 4 In the transparent display device 100 according to one embodiment of the present disclosure, a plurality of first reproducing members 211, a plurality of second reproducing members 212, and a plurality of third reproducing members 213 may be alternately arranged. This is to determine the path (or direction) of the reflected light by separating the first reproducing members 211 reflecting red light from each other by a predetermined interval, separating the second reproducing members 212 reflecting green light by a predetermined interval, and separating the third reproducing members 213 reflecting blue light by a predetermined interval.

[0103] The reason why only the first reproduction member 211 is disposed in the first reproduction area RA1 is because the brightness of red light is insufficient compared with the brightness of green light and blue light. Therefore, the first reproduction member 211 is disposed in the first reproduction area RA1 disposed to overlap (or correspond to) the central portion of the transmission area TA having the largest amount of incident light, so that the brightness of red light emitted to the front surface of the substrate 110 can be increased. Figure 2 and Figure 4 As shown in , a portion of the plurality of first reproduction members 211 may be disposed within a circle as a first reproduction area RA1.

[0104] As described above, since the brightness of red light is insufficient compared to the brightness of green light and blue light, the ratio of the first reproduction members 211 provided in the first to third reproduction areas RA1, RA2, and RA3 corresponding to the transmission area TA may be greater than the ratio of the second and third reproduction members 212 and 213. For example, the plurality of first reproduction members 211, the plurality of second reproduction members 212, and the plurality of third reproduction members 213 may be provided in a ratio of 37.4:33.3:29.3.

[0105] In addition, each of the plurality of reproduction parts 210 can reflect the light of the light emitting area EA incident through the transmission area TA in the first path RL1 toward the second path RL1-1 opposite to the first path RL1, through the difference in refractive index between the base substrate 220 and the cover layer 230 adjacent to the plurality of reproduction parts 210 and the diffraction of the adjacent reproduction parts 210. That is, the plurality of reproduction parts 210 can focus the light to the light emitting position (or location) where the light is emitted in the light emitting area EA and reflect the incident light. To this end, each of the plurality of reproduction parts 210 can be provided in a cylindrical shape having a predetermined diameter and a predetermined height, and can be provided to be separated from each other by a predetermined distance.

[0106] Figure 5 2 is a schematic diagram illustrating only the first reproduction member 211, the second reproduction member 212, and the third reproduction member 213. Figure 5, the height H of each of the plurality of reproducing parts 210 may be greater than the maximum visible light wavelength range. Since the visible light wavelength range is 380nm to 780nm, the maximum visible light wavelength range may be 780nm. In the transparent display device 100 according to one embodiment of the present disclosure, the height H of each of the plurality of reproducing parts 210 may be 1μm or more. When the height of the reproducing part 210 is less than 1μm, it may belong to the visible light wavelength range, in which case the diffraction interference phenomenon in the vertical direction may become serious, so that the second path RL1-1 may change. When the height of the reproducing part 210 is less than 1μm, it does not block the visible light, so that the visible light can be transmitted without being reflected by the reproducing part 210. Therefore, the transparent display device 100 according to one embodiment of the present disclosure is configured so that the height of each of the plurality of reproducing parts 210 is greater than the maximum visible light wavelength range, thereby reflecting the light incident to the reproducing part 210 while preventing the second path RL1-1 from changing. That is, the height H of each of the plurality of reproducing parts 210 may be a factor for determining the path of the light to be reflected. The plurality of reproducing parts 210 may include a plurality of first reproducing members 211, a plurality of second reproducing members 212, and a plurality of third reproducing members 213. Therefore, each of the plurality of first reproducing members 211, a plurality of second reproducing members 212, and a plurality of third reproducing members 213 may be larger than the maximum visible light wavelength range.

[0107] The diameter φ of each of the plurality of reproduction sections 210 may be set to satisfy the following equation: Among them, "a" is the interference constant, "e" is the exponential function, "π" is pi, "h" is Planck's constant, "c" is the speed of light, and "n" is the speed of light. e ” is the effective refractive index, “λ T ” indicates wavelength. Since “a”, “e”, “π”, “h”, “c” and “n e " is a constant, so it can be calculated based on the wavelength λ T The diameter φ of each of the plurality of reproducing parts 210 is determined. Therefore, the first reproducing member 211, the second reproducing member 212, and the third reproducing member 213 may be set to different diameters to reflect light of different colors. For example, the diameter φ2 of each second reproducing member 212 may be smaller than the diameter φ1 of each first reproducing member 211, and may be larger than the diameter φ3 of each third reproducing member 213. Therefore, according to the above formula, the first reproducing member 211 may reflect red light, the second reproducing member 212 may reflect green light, and the third reproducing member 213 may reflect blue light. That is, the diameter φ of each of the plurality of reproducing parts 210 may be a factor for determining the color (or wavelength) of the reflected light.

[0108] Reference Figure 4 and Figure 6 , the interval between each reproducing portion 210 may be smaller than the minimum visible light wavelength range. In this case, the interval refers to the interval between the plurality of reproducing portions 210 arranged in each circle. For example, the interval may refer to the interval arranged in Figure 6 The internal distance RID between the first reproduction members 211 in the first reproduction area RA1 in the first reproduction area RA1. Since the minimum visible light wavelength range is 380nm, the internal distance between the multiple reproduction parts 210 is less than 380nm. The reason for setting the internal distance RID between the multiple reproduction parts 210 (or the multiple first reproduction members 211) to be less than the minimum visible light wavelength range is to reflect the color (or wavelength) of the corresponding visible light. For example, when the internal distance between the multiple reproduction parts is set to exceed the minimum visible light wavelength range, the reproduction part can reflect the ultraviolet wavelength range outside the visible light wavelength range. Therefore, the internal distance RID between the multiple reproduction parts 210 can be less than the minimum visible light wavelength range. In addition, when the internal distance between the reproduction parts 210 is too close, the infrared wavelength range can be reflected. Therefore, the transparent display device 100 according to one embodiment of the present disclosure can be set so that the internal distance between the multiple reproduction parts 210 is less than the minimum visible light wavelength range within the range of not reflecting the infrared wavelength range.

[0109] According to an example, the interval (or inner distance) GID ( Fig. 9 ) may be smaller than the interval (or inner distance) RID between the first reproduction members 211, and smaller than the interval (or inner distance) BID ( Fig.10 ). Therefore, the first reproducing member 211 may reflect red light, the second reproducing member 212 may reflect green light, and the third reproducing member 213 may reflect blue light. For example, the inner distance RID between the first reproducing members 211 may be 95 nm. The inner distance GID between the second reproducing members 212 may be 100 nm. The inner distance BID between the third reproducing members 213 may be 115 nm. As a result, the diameter and the inner distance of each of the plurality of reproducing parts 210 may be a determining factor for reflecting any one of the red light, the green light, and the blue light.

[0110] Figure 6A plurality of first sub-reproducing members 211a, a plurality of second sub-reproducing members 211b, and a plurality of third sub-reproducing members 211c of the plurality of first reproducing members 211 are schematically illustrated. The plurality of first sub-reproducing members 211a may be disposed in the first reproducing area RA1 for increasing the brightness of red light. The plurality of second sub-reproducing members 211b may be disposed in the third reproducing area RA3 adjacent to the second reproducing area RA2. Since the first reproducing member 211 is disposed in the first reproducing area RA1 corresponding to the central portion of the transmission area TA, the first reproducing member 211 may not be disposed in the second reproducing area RA2 adjacent to the first reproducing area RA1.

[0111] like Figure 4 and Figure 6 As shown in , the plurality of second sub-reproducing members 211b may be disposed to surround the plurality of first sub-reproducing members 211a at positions separated from the plurality of first sub-reproducing members 211a by a predetermined distance. For example, the plurality of second sub-reproducing members 211b may be separated from each other by an outer distance RED greater than the inner distance RID. As described above, the inner distance RID is a factor that determines the wavelength, i.e., the color, of the light reflected by the plurality of reproducing parts 210. On the other hand, the outer distance RED is a factor for determining the direction of the light reflected by the plurality of reproducing parts 210. For example, the second sub-reproducing member 211b may reflect the red light from the light emitting area EA to the light emitting position by constructive interference with the first sub-reproducing member 211a located in the central portion of the reproducing area, i.e., the first reproducing area RA1.

[0112] In the transparent display device 100 according to one embodiment of the present disclosure, the external distance RED may be greater than the maximum visible light wavelength range. For example, the external distance RED may be set to be greater than 1 μm. When the external distance is 1 μm or less, the constructive interference with the adjacent first reproduction member 211 becomes too large to change the direction of the reflected light. In addition, when the external distance is too large, the constructive interference with the adjacent first reproduction member 211 hardly occurs, so the light is not reflected to the light emitting position. Therefore, the transparent display device 100 according to one embodiment of the present disclosure may be set so that the external distance of the plurality of reproduction parts 210 is greater than the maximum visible light wavelength range within the range in which the image light can be reflected by the second path opposite to the first path in which the image light is incident through the transmission area TA.

[0113] In addition, the reproduction plate 200 may further include a fourth reproduction area RA4 that does not overlap with the transmission area TA. A portion of the first reproduction member 211, the second reproduction member 212, and the third reproduction member 213 may be disposed in the fourth reproduction area RA4. At least a portion of each of the first reproduction member 211, the second reproduction member 212, and the third reproduction member 213 disposed in the fourth reproduction area RA4 may overlap with the planarization layer 113 and / or the bank 115 disposed in the non-light emitting area in the third axis direction Z.

[0114] The plurality of first reproduction members 211 may further include a third sub-reproduction member 211c. The third sub-reproduction member 211c according to one example may be disposed in the fourth reproduction area RA4 to surround the plurality of second sub-reproduction members 211b. The plurality of third sub-reproduction members 211c may be separated from the plurality of second sub-reproduction members 211b by an outer distance RED greater than the inner distance RID. The plurality of second sub-reproduction members 211b may be separated from the plurality of first sub-reproduction members 211a by a first outer distance RED1, and the plurality of third sub-reproduction members 211c may be separated from the plurality of second sub-reproduction members 211b by a second outer distance RED2. In this case, the second outer distance RED2 may be greater than the first outer distance RED1. This is because, as Figure 4 As shown in FIG. 1 , the number of reproduction members 210 decreases from the first reproduction area RA1 toward the fourth reproduction area RA4.

[0115] Return to reference Figure 4 , light incident on the fourth reproduction area RA4 may not be reflected by the reproduction member 210 and may be eliminated by being waveguided by the reproduction member 210 on the substrate 110. However, the first reproduction member 211, the second reproduction member 212, and the third reproduction member 213 disposed in the fourth reproduction area RA4 may contribute to forming an optical path of light reflected by the first, second, and third reproduction members 211, 212, and 213 disposed in the first to third reproduction areas RA1, RA2, and RA3 through diffraction (constructive or destructive interference).

[0116] In addition, if Figure 4 As shown in FIG. 1 , light emitted from the light emitting area EA and incident toward the first sub-reproducing member 211a through the transmission area TA at the first path RL1 may be reflected through the second path RL1-1 opposite to the first path RL1. Light emitted from the light emitting area EA and incident toward the second sub-reproducing member 211b through the transmission area TA at the first path RL2 may be reflected to the second path RL2-1 opposite to the first path RL2. Light emitted from the light emitting area EA and incident toward the third sub-reproducing member 211c through the transmission area TA at the first path RL3 may be waveguided and eliminated.

[0117] Figure 7 2 is a schematic diagram illustrating that the second sub-reproducing member 211b and the third sub-reproducing member 211c are provided only in the third and fourth reproduction areas RA3 and RA4, respectively, to describe diffraction (or constructive and destructive interference) through the plurality of reproduction parts 210. Figure 7 , light incident from the transmission area TA to the third reproduction area RA3 may be reflected by the second sub-reproducing member 211b and diffracted in the form of waves. Light incident from the transmission area TA to the fourth reproduction area RA4 may be reflected by the third sub-reproducing member 211c and diffracted in the form of waves. Figure 7 As shown in FIG. 1 , at least a portion of the waves diffracted by the second sub-reproducing member 211b and the third sub-reproducing member 211c may overlap with each other, and constructive interference may occur in the overlapping portion, thereby forming light having an oblique path VL, as shown in FIG. Figure 7 As shown in . The light of the oblique path VL affects the third reproduction area RA3, resulting in the formation of a second path RL2-1.

[0118] In addition, the second sub-reproducing member 211b and the third sub-reproducing member 211c may be disposed to be separated from each other by a second outer distance RED2. Since no sub-reproducing member capable of reflecting red light is disposed within the second outer distance RED2, diffraction cannot be generated, and thus the number (or amount) of overlapping waves is small. Therefore, constructive interference hardly occurs between the second sub-reproducing member 211b and the third sub-reproducing member 211c, and thus light having a vertical path EL is eliminated, so that the second sub-reproducing member 211b and the third sub-reproducing member 211c cannot contribute to changing the optical path. As a result, in the transparent display device 100 according to one embodiment of the present disclosure, the final path of the light reflected by the reproduction portion 210 may be determined by the effects of constructive and destructive interference as diffraction characteristics of the light.

[0119] Figure 8 1 is a schematic diagram illustrating only the first sub reproduction member 211a provided in the first reproduction area RA1 and the third sub reproduction member 211c provided in the fourth reproduction area RA4.

[0120] The light RL3 incident on the fourth reproduction area RA4 is incident on a path exceeding a threshold angle that can be reflected by the third sub-reproducing member 211c, and thus is not reflected by the third sub-reproducing member 211c. Figure 8 Therefore, the light incident toward the fourth reproduction area RA4 in the third path RL3 may be eliminated by being waveguided to the upper surface of the third sub-reproducing member 211 c and the upper surface of the base substrate 220 .

[0121] Next, light incident toward the first reproduction area RA1 in the first path RL1 may be reflected within the first sub-reproducing member 211a due to the difference in the refractive index n1 of the base substrate 220, the refractive index n2 of the first sub-reproducing member 211a, and the refractive index n3 of the cover layer 230, and then may be reflected in the second path RL1-1. Such reflection may be achieved by Snell's law, that is, when a wave moves from one medium to another, the ratio of the sign value of the incident angle to the sign value of the refraction angle is always constant. The refractive index n1 of the base substrate 220 may be greater than the refractive index n3 of the cover layer 230 and less than the refractive index n2 of each of the plurality of reproduction parts 210. For example, the refractive index n1 of the base substrate 220 may be 1.7 to 1.8, the refractive index n3 of the cover layer 230 may be 1.4 to 1.5, and the refractive index n2 of each of the plurality of reproduction parts 210 may be 2.

[0122] In the transparent display device 100 according to one embodiment of the present disclosure, image light incident from the transmission area TA in the first path RL1 may be reflected to a second path RL1-1 opposite to the first path RL1 by using the difference in refractive index among the base substrate 220, the cover layer 230, and the plurality of reproduction parts 210, as shown in FIG. Figure 8 As shown in . In this case, the second path RL1-1 may represent a final path combined with constructive and destructive interference of the adjacent reproduction portion 210. As a result, in the transparent display device 100 according to one embodiment of the present disclosure, the return reflection path may be determined by a plurality of reproduction portions 210 having a predetermined diameter and height and the intervals between the plurality of reproduction portions 210 to reflect the corresponding color. The return reflection path may be formed by the difference in refractive index between the base substrate 220, the cover layer 230 and the plurality of reproduction portions 210 and the constructive and destructive interference of the light diffracted by the plurality of reproduction portions 210. The light reflected by the plurality of reproduction portions 210 may be emitted to the front surface of the substrate 110, and the brightness of the image may be increased by combining the light reflected by the plurality of reproduction portions 210 with the light emitted from the light emitting area EA and emitting it to the front surface, thereby improving the visibility of the image to the user.

[0123] Reference Figure 5, the height CH of the cover layer 230 can be at least 1.5 times to twice the height H of the multiple reproduction parts 210. The cover layer 230 according to an example can be made of an organic material similar to the planarization layer 113. Since the organic material has an absorption coefficient, when its thickness is too thin and less than 1.5 times, the light absorptivity is reduced to increase the interference constructive phase. When the enhanced interference increases, the direction of the reflected light changes. On the contrary, when the thickness of the cover layer 230 is too thick and exceeds twice, the light absorptivity is increased to reduce the amount of reflected light, and thus the image may be seen blurred. Therefore, in the transparent display device 100 according to an embodiment of the present disclosure, the height CH of the cover layer is 1.5 times to 2 times the height H of the multiple reproduction parts 210, so that the light is reflected to the light path opposite to the light path of the incident light, and the image is prevented from being seen blurred.

[0124] Return to reference Figure 4 In the transparent display device 100 according to one embodiment of the present disclosure, the reproduction plate 200 may be disposed to be separated from the substrate 110 by a predetermined distance D. When the visibility of the image light is reduced, that is, in the non-transmission mode in which the external light is not transmitted, the reproduction plate 200 may be disposed above the rear surface of the display panel. In the transmission mode in which the external light transmits the display panel, the reproduction plate 200 may not be disposed above the rear surface of the display panel. Therefore, at least a portion of the reproduction plate 200 may be disposed to selectively overlap with the rear surface of the substrate 110 in the non-transmission mode and the transmission mode. As a result, the reproduction plate 200 may be movably disposed relative to the substrate 110, so that the reproduction plate 200 may be separated from the substrate 110 by a predetermined distance D to avoid damage due to friction with the substrate 110.

[0125] The reproduction plate 200 according to one example may be disposed at 10 μm or less from the rear surface of the substrate 110. When the reproduction plate 200 is disposed at a distance exceeding 10 μm from the rear surface of the substrate 110, the distance between the rear surface of the substrate 110 and the plurality of reproduction parts 210 increases, so that the reflectivity of the reproduction parts 210 may be reduced. In addition, the directivity of the light reflected by the reproduction parts 210 may be changed. Therefore, in the transparent display device 100 according to one embodiment of the present disclosure, within a range in which friction does not occur between the reproduction plate 200 and the substrate 110, the reproduction plate 200 is disposed at 10 μm or less from the rear surface of the substrate 110, so that the reflectivity of the reproduction parts 210 may be prevented from being deteriorated, and the path of the reflected light may be prevented from being changed.

[0126] In the transparent display device 100 according to one embodiment of the present disclosure, at least a portion of the reproduction plate 200 can be moved during the non-transmission mode so as to overlap with the rear surface of the substrate 110, and at least a portion of the reproduction plate 200 can be moved during the transmission mode so as not to overlap with the rear surface of the substrate 110, so that the behavior of extending the black film can be omitted, thereby shortening the switching time between the transmission mode and the non-transmission mode.

[0127] Furthermore, the transparent display device 100 according to one embodiment of the present disclosure is provided such that the reproduction plate 200 is disposed over the rear surface of the substrate 110 during the non-transmissive mode, thereby reducing manufacturing costs compared to the case where a transmissive area is switched to be opaque in a display panel.

[0128] In addition, each of the plurality of reproduction parts 210 of the reproduction plate 200 may be made of a material having a refractive index higher than that of each of the base substrate 220 and the cover layer 230 to reflect light to the second path. Each reproduction part 210 according to one example may be made of TiX, but is not limited thereto. Each reproduction part 210 may be made of another material as long as the image light can be reflected to the second path opposite to the first path to which the image light is incident.

[0129] The base substrate 220 supporting the plurality of reproduction parts 210 may have a low light transmittance to prevent external light from being transmitted through the transmission area TA. The base substrate 220 according to one example may include a black-based material. Therefore, the external light incident on the rear surface of the substrate 110 is covered by the base substrate 220 including the black material, so that the external light cannot be incident on the transmission area TA of the substrate 110. Therefore, the transparent display device 100 according to one embodiment of the present disclosure can improve the brightness of the image light emitted to the front surface of the substrate 110 while preventing the external light from being incident through the transmission area TA, thereby increasing or maximizing the user's visibility of the image light.

[0130] Fig. 9 is along Figure 1 1 is a schematic cross-sectional view taken along line II-II' shown in FIG. 1 , which illustrates the optical path of the second reproducing member.

[0131] Reference Fig. 9, a plurality of second reproduction members 212 may be arranged in the second reproduction area RA2, the third reproduction area RA3, and the fourth reproduction area RA4. The second reproduction members 212 arranged in the second reproduction area RA2, the third reproduction area RA3, and the fourth reproduction area RA4 may be arranged to have a predetermined internal distance GID. The internal distance GID of the second reproduction member 212 according to an example may be less than the minimum visible light wavelength range. This is to reflect green (or green wavelength). For example, when the internal distance between the second reproduction members 212 is greater than the minimum visible light wavelength range, the second reproduction member 212 may reflect the ultraviolet wavelength range instead of the visible light wavelength range. Therefore, the internal distance RID between the plurality of second reproduction members 212 may be less than the minimum visible light wavelength range. In addition, when the internal distance between the second reproduction members 212 is too close, the infrared wavelength range may be reflected. Therefore, in the transparent display device 100 according to an embodiment of the present disclosure, the internal distance GID between the plurality of second reproduction members 212 may be less than the minimum visible light wavelength range, and may be arranged within the range of not reflecting the infrared wavelength range.

[0132] In addition, the second reproduction members 212 disposed in the second reproduction area RA2, the third reproduction area RA3, and the fourth reproduction area RA4 may be disposed to have a predetermined outer distance GED. This is because the outer distance GED is a factor for determining the direction of light reflected by the plurality of second reproduction members 212. For example, the second reproduction member 212 disposed in the third reproduction area RA3 may reflect green light so that the light is returned to the position emitted from the light emitting area EA by constructive interference with the second reproduction member 212 located in the second reproduction area RA2. Therefore, as Fig. 9 As shown in , light incident from the transmission area TA toward the second reproduction member 212 in the first paths GL1 and GL2 may be reflected to the second paths GL1-1 and GL2-1 opposite to the first paths GL1 and GL2. A portion of the light reflected (or returned) by the second reproduction member 212 to the second paths GL1-1 and GL2-1 may be emitted through the second substrate 110', while another portion of the light may be reflected at the boundary surface of the encapsulation layer 118 or at the lower surface of the second substrate 110' and then reflected toward the pixel electrode 114. The light incident to the pixel electrode 114 may be reflected by the pixel electrode 114 and emitted to the second substrate 110'. As a result, the light reflected by the second reproduction member 212 may be combined with the light emitted from the light emitting area EA and directly emitted to the second substrate 110', thereby improving the visibility of the image light to the user.

[0133] like Fig. 9As shown in FIG. 2 , light incident in the third path GL3 toward the fourth reproduction area RA4 is not reflected by the second reproduction member 212 because the light is incident at an angle exceeding a threshold angle that can be reflected by the second reproduction member 212. Therefore, the light incident at the fourth reproduction area RA4 can be eliminated by being waveguided to the upper surface of the second reproduction member 212 and the upper surface of the base substrate 220.

[0134] As a result, a return reflection path of the green light incident from the transmission area TA to the plurality of second reproduction members 212 may be determined by the plurality of second reproduction members 212 having a predetermined diameter and height and the intervals between the plurality of second reproduction members 212. The return reflection path may be formed by a difference in refractive index between the base substrate 220, the cover layer 230, and the plurality of second reproduction members 212, and constructive and destructive interference of light diffracted by the plurality of second reproduction members 212. Since the difference in refractive index between the plurality of second reproduction members 212, the base substrate 220, and the cover layer 230, and constructive and destructive interference due to diffraction of light are as described in the plurality of first reproduction members 211, a detailed description thereof will be omitted.

[0135] Fig.10 is along Figure 1 1 is a schematic cross-sectional view taken along line III-III' shown in FIG. 1 , which illustrates the optical path of the third reproducing member.

[0136] Reference Fig.10 , a plurality of third reproduction members 213 may be arranged in the second reproduction area RA2, the third reproduction area RA3, and the fourth reproduction area RA4. The third reproduction members 213 arranged in the second reproduction area RA2, the third reproduction area RA3, and the fourth reproduction area RA4 may be arranged to have a predetermined internal distance BID. The internal distance BID of the third reproduction member 213 according to an example may be less than the minimum visible light wavelength range. This is to reflect blue (or blue wavelength). For example, when the internal distance between the third reproduction members 213 is greater than the minimum visible light wavelength range, the third reproduction member 213 may reflect the ultraviolet wavelength range instead of the visible light wavelength range. Therefore, the internal distance BID between the plurality of third reproduction members 213 may be less than the minimum visible light wavelength range. In addition, when the internal distance between the third reproduction members 213 is too close, the infrared wavelength range may be reflected. Therefore, in the transparent display device 100 according to an embodiment of the present disclosure, the internal distance BID between the plurality of third reproduction members 213 may be less than the minimum visible light wavelength range, and may be set within the range of not reflecting the infrared wavelength range.

[0137] In addition, the third reproduction members 213 disposed in the second reproduction area RA2, the third reproduction area RA3, and the fourth reproduction area RA4 may be disposed to have a predetermined outer distance BED. This is because the outer distance BED is a factor that determines the direction of light reflected by the plurality of third reproduction members 213. For example, the third reproduction member 213 disposed in the third reproduction area RA3 may reflect blue light so that the light is returned to the position emitted from the light emitting area EA by constructive interference with the third reproduction member 213 located in the second reproduction area RA2. Therefore, as Fig.10 As shown in FIG. 1 , light incident from the transmission area TA toward the third reproduction member 213 in the first paths BL1 and BL2 may be reflected to the second paths BL1-1 and BL2-1 opposite to the first paths BL1 and BL2. A portion of the light reflected (or returned) by the third reproduction member 213 to the second paths BL1-1 and BL2-1 may be emitted through the second substrate 110', while another portion of the light may be reflected at the boundary surface of the encapsulation layer 118 or the lower surface of the second substrate 110' and then reflected toward the pixel electrode 114. The light incident to the pixel electrode 114 may be reflected by the pixel electrode 114 and emitted to the second substrate 110'. As a result, the light reflected by the third reproduction member 213 may be combined with the light emitted from the light emitting area EA and directly emitted to the second substrate 110', thereby improving the visibility of the image light to the user.

[0138] like Fig.10 As shown in FIG. 2 , light incident in the third path BL3 toward the fourth reproduction area RA4 is not reflected by the second reproduction member 212 because the light is incident at an angle exceeding a threshold angle that can be reflected by the third reproduction member 213. Therefore, the light incident at the fourth reproduction area RA4 can be eliminated by being waveguided to the upper surface of the third reproduction member 213 and the upper surface of the base substrate 220.

[0139] As a result, a return reflection path of the blue light incident from the transmission area TA to the plurality of third reproduction members 213 may be determined by the plurality of third reproduction members 213 having a predetermined diameter and height and the intervals between the plurality of third reproduction members 213. The return reflection path may be formed by a difference in refractive index between the base substrate 220, the cover layer 230, and the plurality of third reproduction members 213, and constructive and destructive interference of light diffracted by the plurality of third reproduction members 213. Since the difference in refractive index between the plurality of third reproduction members 213, the base substrate 220, and the cover layer 230, and constructive and destructive interference due to diffraction of light are as described in the plurality of first reproduction members 211, a detailed description thereof will be omitted.

[0140] Although the organic light emitting layer 116 has a structure in which the organic light emitting layer 116 is commonly provided in a plurality of sub-pixels SP to emit white light, the organic light emitting layer 116 is not limited thereto, and the plurality of sub-pixels SP may be provided to emit light of different colors. When the plurality of sub-pixels SP are provided to emit light of different colors, only the plurality of reproducing portions 210 that may reflect light of the corresponding colors may be provided in at least a portion of the reproducing plate 200 overlapping with the transmission area. For example, only the first reproducing member 211 may be provided in at least a portion of the reproducing plate 200 overlapping with the transmission area TA adjacent to the red sub-pixel SP, only the second reproducing member 212 may be provided in at least a portion of the reproducing plate 200 overlapping with the transmission area TA adjacent to the green sub-pixel SP, and only the third reproducing member 213 may be provided in at least a portion of the reproducing plate 200 overlapping with the transmission area TA adjacent to the blue sub-pixel SP, but the first to third reproducing members are not limited thereto. The first to third reproducing members 211, 212, and 213 of the same shape may be disposed in at least a portion of the reproducing plate 200 overlapping the transmission area TA adjacent to each of the red, green, and blue sub-pixels SP to simplify manufacturing.

[0141] According to the present disclosure, the following advantageous effects can be obtained.

[0142] In the present disclosure, the reproduction plate is disposed at a position corresponding to the transmission area, so that external light is covered by the reproduction plate and cannot pass through the transmission area, thereby improving the visibility of the image to the user.

[0143] In addition, since a plurality of reproduction parts are disposed at positions corresponding to the transmission areas, light emitted toward the rear surface (or reproduction plate) may be reflected toward the front surface (or light emitting area) through the transmission areas, thereby improving the brightness of an image.

[0144] Furthermore, in the present disclosure, a reproduction plate is selectively disposed over the rear surface of the substrate, thereby shortening a switching time between a transmission mode and a non-transmission mode.

[0145] Furthermore, in the present disclosure, the reproduction plate is selectively provided over the rear surface of the substrate, so that the manufacturing cost can be reduced compared with the case where the transmission area is electrically converted into black.

[0146] It is obvious to those skilled in the art that the above disclosure is not limited by the above embodiments and drawings, and various substitutions, modifications and changes can be made in the disclosure without departing from the spirit or scope of the disclosure. Therefore, the scope of the disclosure is defined by the appended claims, and all changes or modifications derived from the meaning, scope and equivalent concepts of the claims are intended to fall within the scope of the disclosure.

Claims

1. A transparent display device, comprising: a substrate comprising a plurality of pixels, each of the plurality of pixels having a light emitting region and a transmissive region; as well as a reproduction plate arranged parallel to the base plate, wherein the reproduction plate comprises a plurality of reproduction portions at least partially overlapping the transmission areas, wherein the plurality of reproduction portions are provided on the back surface of the substrate, and wherein the plurality of reproduction sections are arranged to be spaced apart and reflect light. 2 . The transparent display device according to claim 1 , wherein the plurality of reproduction parts reflect light emitted from the light emitting area and incident in a first path through the transmission area to a second path opposite to the first path. 3 . The transparent display device of claim 1 , wherein a height of each of the plurality of reproduction parts is greater than a maximum visible light wavelength range. The transparent display device according to claim 1 , wherein an interval between the respective reproduction parts is smaller than a minimum visible light wavelength range.

5. The transparent display device according to claim 1, wherein the diameter φ of each of the plurality of reproduction parts satisfies Where "a" is the interference constant, "e" is the exponential function, "π" is the circumference constant, "h" is Planck's constant, "c" is the speed of light, and "n e ” is the effective refractive index, and "λ T ” is the wavelength.

6. The transparent display device according to claim 1, wherein the plurality of reproduction parts comprises: a plurality of first reproduction members reflecting red light; a plurality of second reproduction members reflecting green light; and A plurality of third reproduction members reflecting blue light. 7 . The transparent display device according to claim 6 , wherein a ratio of the plurality of first reproduction members to the transmission area is greater than a ratio of the plurality of second reproduction members to the transmission area and a ratio of the plurality of third reproduction members to the transmission area. 8 . The transparent display device according to claim 6 , wherein a diameter of each of the second reproducing members is smaller than a diameter of each of the first reproducing members and larger than a diameter of each of the third reproducing members. 9 . The transparent display device according to claim 6 , wherein an interval between the second reproducing members is larger than an interval between the first reproducing members and smaller than an interval between the third reproducing members. 10 . The transparent display device of claim 6 , wherein a portion of the plurality of first reproduction members is disposed to overlap with a central portion of the transmission area.

11. The transparent display device according to claim 6, wherein the transmission area includes a first transmission area as a central portion, a third transmission area as an edge portion, and a second transmission area located between the first transmission area and the third transmission area, The reproduction plate includes a first reproduction area overlapping the first transmission area, a second reproduction area overlapping the second transmission area, and a third reproduction area overlapping the third transmission area, The first reproduction member includes a plurality of first sub-reproduction members provided in the first reproduction area and a plurality of second sub-reproduction members provided in the third reproduction area, and The plurality of second sub-reproducing members surround the plurality of first sub-reproducing members.

12. The transparent display device according to claim 11, wherein the respective first sub-reproducing members are separated from each other by an inner distance, and The plurality of first sub-reproducing members and the plurality of second sub-reproducing members are spaced apart from each other by a first outer distance greater than the inner distance.

13. The transparent display device according to claim 12, wherein the reproduction plate includes a fourth reproduction area that does not overlap with the transmission area, The first reproduction member includes a plurality of third sub-reproduction members disposed in the fourth reproduction area and surrounding the plurality of second sub-reproduction members, The plurality of third sub-reproducing members are separated from the plurality of second sub-reproducing members by a second outer distance, and The first outer distance is greater than the second outer distance.

14. The transparent display device according to claim 11, wherein the reproduction plate includes a fourth reproduction area that does not overlap with the transmission area, and At least a portion of each of the first reproduction member, the second reproduction member, and the third reproduction member is disposed in the fourth reproduction area. 15 . The transparent display device according to claim 1 , wherein the reproduction plate is disposed 10 μm or less from the substrate.

16. The transparent display device according to claim 1, wherein the reproduction plate comprises: a base substrate on which the plurality of reproduction portions are disposed; and a cover layer covering the base substrate and the plurality of reproduction portions, and A refractive index of the base substrate is greater than a refractive index of the cover layer and is smaller than a refractive index of each of the plurality of reproduction portions. 17 . The transparent display device of claim 16 , wherein a height of the cover layer is 1.5 to 2 times a height of the plurality of reproduction parts. 18 . The transparent display device according to claim 1 , wherein the plurality of reproduction parts are arranged in the form of a circle or a circular track.

19. A transparent display device, comprising: a substrate comprising a plurality of pixels, each of the plurality of pixels having a light emitting region and a transmissive region; as well as a reproduction plate that reflects light emitted from the light emitting area and incident through the transmission area, The reproduction plate comprises: a plurality of first reproducing members reflecting red light incident through the transmission area; a plurality of second reproducing members that reflect green light incident through the transmission area; and a plurality of third reproducing members that reflect blue light incident through the transmission area, and The plurality of first reproducing members, the plurality of second reproducing members, and the plurality of third reproducing members are alternately arranged.

20. The transparent display device of claim 19, wherein each of the plurality of first reproducing members, the plurality of second reproducing members, and the plurality of third reproducing members reflects light emitted from the light emitting area and incident in a first path through the transmission area to a second path opposite to the first path. 21 . The transparent display device of claim 19 , wherein a height of each of the plurality of first reproduction members, the plurality of second reproduction members, and the plurality of third reproduction members is greater than a maximum visible light wavelength range. 22 . The transparent display device of claim 19 , wherein a diameter of each of the second reproduction members is smaller than a diameter of each of the first reproduction members and larger than a diameter of each of the third reproduction members. 23 . The transparent display device of claim 19 , wherein an interval of each of the plurality of first reproducing members, the plurality of second reproducing members, and the plurality of third reproducing members is smaller than a minimum visible light wavelength range. 24 . The transparent display device according to claim 23 , wherein an interval between the second reproduction members is larger than an interval between the first reproduction members and smaller than an interval between the third reproduction members. 25 . The transparent display apparatus of claim 19 , wherein a portion of the plurality of first reproduction members is disposed to overlap a central portion of the transmission area. 26 . The transparent display apparatus according to claim 19 , wherein the plurality of first reproducing members, the plurality of second reproducing members, and the plurality of third reproducing members are provided in the form of a circle or a circular track.

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