DISPLAY DEVICE HAVING A BACKLIGHT UNIT AND A LIQUID CRYSTAL PANEL

Abstract

Display device (DP) comprising: a backlight unit (200), a liquid crystal panel (100) arranged on the backlight unit (200), and a viewing angle control unit (400, 500) arranged between the backlight unit (200) and the liquid crystal panel (100), wherein the viewing angle control unit (400, 500) comprises light-blocking structures (415, 551) having a light-blocking material and variable structures (425, 552) arranged between a first control electrode (423, 530) and a second control electrode (424, 540), wherein the variable structures (425, 552) extend in a direction perpendicular to the light-blocking structures (415, 551), and wherein a transmittance of each variable structure (425, 552) is changed according to a voltage applied to the first control electrode (423, 530) and the second control electrode (424, 540), wherein the light-blocking structures (415, 551) are arranged between the first control electrode (423, 530) and the second control electrode (424, 540).

Description

Cross-Reference to Related ApplicationThis application claims priority to Korean Patent Application No. 10-2020-0186518 filed on Dec. 29, 2020.BackgroundFIELD OF DISCLOSUREThe present disclosure relates to a display device in which a backlight unit and a liquid crystal panel are stacked.Background DescriptionGenerally, a display device is provided to realize an image. For example, the display device may include a liquid crystal panel disposed on a backlight unit. The backlight unit may provide light to the liquid crystal panel. The liquid crystal panel may realize the image using the light provided from the backlight unit.The display device can be used in various places. For example, the display device may be installed in front of a passenger seat of a vehicle. The image realized by the display device can be recognized by persons around a user. For example, the image realized by the display device installed in front of a passenger seat of a vehicle may be recognized by the driver of the corresponding vehicle. That is, the image realized by the display device may draw the gaze of the driver, thereby increasing the likelihood of an accident.US 2019 / 0 163 020 A1 describes a light beam direction control apparatus comprising a plurality of leaf elements switching between a transparent state and a light absorption state according to an applied voltage, and a plurality of polymer dispersed liquid crystal parts arranged along the primary surface of the substrate in an associated manner between the plurality of leaf elements, the polymer dispersed liquid crystal parts each having a solid polymer resin part and liquid crystal droplets dispersed in the solid polymer resin part, the polymer dispersed liquid crystal parts each changing the degree of scattering of emitted light by changing the degree of scattering of incident light according to an applied voltage.DE 41 07 021 C2 describes an apparatus for displaying a television image on a television monitor which can be used in a vehicle interior, wherein a liquid crystal filter is arranged on a television monitor screen having a variable transmittance according to a voltage applied to a whole-area electrode, wherein the liquid crystal filter serves to limit an angle of the visible field around the position of the driver's seat, wherein a high image transmittance is provided at a position of the passenger seat, and a leaf type filter is arranged between the screen of the television monitor and the liquid crystal filter, wherein the leaf type filter comprises a plurality of fine leaves, each longitudinal direction of the leaves being aligned along the horizontal direction.OverviewAccordingly, the present disclosure is directed to a display device that substantially eliminates one or more problems due to limitations and disadvantages of the related art.More specifically, an object of the present disclosure is to provide a display device capable of selectively limiting the viewing angle.An object of the present disclosure is also to provide a display device capable of reducing or minimizing a visibility deviation caused by a change in a viewing angle.Additional advantages and characteristics of the disclosure will be set forth in part in the description which follows, and in part will become apparent to one skilled in the art upon examination of the following, or may be learned from practice of the disclosure. Other features of the disclosure may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.To achieve the above and other advantages and in accordance with the present disclosure as embodied and broadly described herein, a display device according to claim 1 and a display device according to claim 9 are provided. Preferred embodiments are described in the dependent claims. In accordance with an aspect of the present disclosure, there is provided a display device including a backlight unit. A liquid crystal panel is disposed on the backlight unit. A viewing angle control unit is disposed between the backlight unit and the liquid crystal panel. The viewing angle control unit has light blocking structures and variable structures. The light blocking structures comprise a light blocking material. The variable structures are arranged between a first control electrode and a second control electrode. The variable structures extend in a direction perpendicular to the light blocking structures. The transmittance of each variable pattern is varied according to a voltage applied to the first control electrode and the second control electrode. The light blocking structures are arranged between the first control electrode and the second control electrode.The light blocking material may comprise a black dye.Each of the variable structures may include a transparent fluid and black particles. The black particles may be dispersed in the transparent fluid.Each of the variable structures may be surrounded by a control insulating layer.The backlight unit may include a light guide plate and a light source element. The light guide plate may include a first side, a second side, a third side, and a fourth side. The second side may be perpendicular to the first side. The third side may be opposite the second side. The fourth side may be opposite the first side. The light source element may include a first light source device, a second light source device, and a third light source device. The first light source device may be disposed on the first side of the light guide plate. The second light source device may be disposed on the second side of the light guide plate. The third light source device may be disposed on the third side of the light guide plate.The first side of the light guide plate may extend in the same direction as the light blocking structures.The first side of the light guide plate may have a length longer than the second side and the third side of the light guide plate.In another aspect, a display device is provided that includes a backlight unit. A viewing angle control unit is disposed on the backlight unit. A liquid crystal panel is disposed on the viewing angle control unit. The viewing angle control unit includes light blocking structures and first variable structures. The light blocking structures extend in a first direction. The first variable structures extend in a second direction perpendicular to the first direction. The first variable structures are arranged between a first control electrode and a second control electrode. Each of the first variable structures includes an electrochromic material. The light blocking structures are arranged between the first control electrode and the second control electrode.Each of the first variable structures may include a metal oxide.The first control electrode may include first electrode structures. The first electrode structures extend side by side in the second direction. Each of the first variable structures may overlap one of the first electrode structures.Each of the first variable structures may have a horizontal width equal to a corresponding first electrode structure.A lower control substrate and an upper control substrate may be disposed between the backlight unit and the liquid crystal panel. The light blocking structures may be disposed between the first lower control substrate and the first upper control substrate. The first control electrode, the variable structures, and the light blocking structures and the second control electrode may be sequentially stacked between the lower control substrate and the upper control substrate.An electrode insulating layer may be disposed between the first variable structures and the light blocking structures.Brief Description of the DrawingsThe accompanying drawings, which are included to provide a further understanding of the disclosure and which are incorporated in and constitute a part of this application, illustrate one or more aspects of the disclosure and together with the description serve to explain the principle of the disclosure.In the drawings:FIG. 1 is a view showing a location where a display device according to an aspect of the present disclosure is used,FIG. 2 is a view schematically showing the display device according to the aspect of the present disclosure,FIG. 3 is a view showing a first control member of the display device according to the aspect of the present disclosure,FIG. 4 is a view showing a second control member of the display device according to the aspect of the present disclosure,FIGS. 5A and 5B are views illustrating a propagation direction of light passing through the second control element when a driving voltage is applied to a first control electrode and a second control electrode in the display device according to the aspect of the present disclosure,FIGS. 6A and 6B are views showing a propagation direction of light passing through the second control element when a driving voltage is not applied to a first control electrode and a second control electrode in the display device according to the aspect of the present disclosure; andFIGS. 7, 8A, 8B, 9, 10, 11A, and 11B are views illustrating a display device according to another aspect of the present disclosure.DETAILED DESCRIPTIONHereinafter, details concerning the above characteristics, technical configurations, and operational effects of the aspects of the present disclosure will be clearly understood by the following detailed description with reference to the drawings illustrating some aspects of the present disclosure. Here, the aspects of the present disclosure are provided to allow the technical idea(s) of the present disclosure to be satisfactorily transmitted to those skilled in the art, and thus the present disclosure may be embodied in other forms and is not limited to the aspects described below.Moreover, the same or extremely similar elements may be denoted by the same reference numerals throughout the description, and in the drawings, the lengths and thicknesses of layers and regions may be exaggerated for convenience. It is understood that when a first element is referred to as being "on" a second element, a third element may be disposed between the first and second elements, although the first element may be disposed on the second element so as to contact the second element.Here, terms such as "first" and "second" may be used to distinguish any element from another element. However, the first element and the second element may be arbitrarily named according to the convention of those skilled in the art without departing from the technical content of the present disclosure.The terms used in the description of the present disclosure are used only to describe certain aspects, and are not intended to limit the scope of the present disclosure. For example, an element described in the singular is intended to include a plurality of elements, unless the context clearly indicates otherwise. Moreover, in the description of the present disclosure, it is further understood that the terms "comprise" and "include" specify the presence of stated characteristics, integers, steps, operations, elements, components, and / or combinations thereof, but do not preclude the presence or addition of one or more other characteristics, integers, steps, operations, elements, components, and / or combinations thereof.Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example aspects belong. It is further understood that terms, such as those defined in generally used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein.FIG. 1 is a view showing a location where a display device DP according to an aspect of the present disclosure is used.Referring to FIG. 1, the display device DP according to the aspect of the present disclosure may be installed in front of a passenger seat PS of a vehicle. Therefore, the display device DP according to the aspect of the present disclosure may limit the viewing angle to prevent accidents caused by the distraction of the driver seated on the adjacent driver seat DS when the vehicle is in motion. For example, the display device DP according to the aspect of the present disclosure may include a viewing angle control unit 400 between a liquid crystal panel 100 and a backlight unit 200, as shown in FIGS. 2 to 4.The liquid crystal panel 100 may realize an image provided to a user. For example, the liquid crystal panel 100 may include a liquid crystal layer between two substrates. The transmittance of the liquid crystal layer may be changed according to an electric field formed between a pixel electrode and a common electrode. For example, the liquid crystal layer may comprise a liquid crystal of an IPS (in-plane switching) mode, an ECB (electronically controlled birefringence) mode or a TN (twisted nematic) mode. A linear polarizer 310 and 320 may be disposed on an outer surface of the liquid crystal panel 100. For example, the liquid crystal panel 100 may be disposed between a first linear polarizer 310 and a second linear polarizer 320. The transmission axis of the second linear polarizer 320 may be perpendicular to the transmission axis of the first linear polarizer 310.The backlight unit 200 may provide light to the liquid crystal panel 100. For example, the liquid crystal panel 100 may be disposed on the backlight unit 200. The backlight unit 200 may include a light source element 210 and a light guide plate 220. The light source element 210 may be disposed on one side of the light guide plate 220. The light source element 210 may emit light. For example, the light source element 210 may include a light source 211 and a printed circuit board 212 in which the light source 211 is mounted. The light source 211 may include or be an LED. The light incident from the light source element 210 may be emitted through an entire upper surface of the light guide plate 220. For example, the light guide plate 220 may function as a surface light source. For example, the liquid crystal panel 100 may be disposed on the upper surface of the light guide plate 220.The backlight unit 200 may include an optical sheet 230 disposed between the upper surface of the light guide plate 220 and the liquid crystal panel 100. The optical film 230 may prevent the variation of characteristics of light provided to each region of the liquid crystal panel 100. The optical film 230 may include a plurality of optical layers 231 and 232. For example, the optical sheet 230 may have a stacked structure of a diffusion layer 231 and a prism layer 232. The backlight unit 200 may include a reflective plate 240 disposed on a lower surface of the light guide plate 220, the lower surface of the light guide plate 220 being opposite to the upper surface of the light guide plate 220 that is opposite to the liquid crystal panel 100. The reflective plate 240 may reflect the light emitted from the lower surface of the light guide plate 220 toward the liquid crystal panel 100. Therefore, in the display device according to the aspect of the present disclosure, loss of light can be reduced or minimized.The viewing angle control unit 400 may be disposed between the liquid crystal panel 100 and the backlight unit 200. For example, the viewing angle control unit 400 may be disposed between the optical film 230 of the backlight unit 200 and the first linear polarizer 310. The propagation direction of the light emitted from the backlight unit 200 may be limited by the viewing angle control unit 400. For example, the viewing angle control unit 400 may include a first control element 410 and a second control element 420.The first control element 410 may include light blocking structures 415 disposed between a first lower control substrate 411 and a first upper control substrate 412. The light blocking structures 415 may extend side by side in a first direction X. The light blocking structures 415 may include a light blocking material. For example, the light blocking structures 415 may include a black colorant such as carbon black. Therefore, in the display device DP according to the aspect of the present disclosure, the viewing angle in a second direction Z that is perpendicular to the first direction X may be limited. The first direction X may be a left-to-right direction (or horizontal direction) of the user, and the second direction Z may be a vertical direction of the user. For example, in the display device DP according to the aspect of the present disclosure, the reflection of the realized image by a windshield FW of the vehicle can be prevented by the light blocking structures 415. Therefore, in the display device DP according to the aspect of the present disclosure, the driver's distraction can be reduced or prevented.The first control element 410 may include a first control insulating layer 416 surrounding the light blocking structures 415. The first control insulating layer 416 may include an insulating material. The first control insulating layer 416 may include a transparent material. For example, the light emitted from the backlight unit 200 may pass through the first control insulating layer 416 between the light blocking structures 415. A space between the first lower control substrate 411 and the first upper control substrate 412 may be completely filled by the light blocking structures 415 and the first control insulating layer 416. Therefore, in the display device DP according to the aspect of the present disclosure, damage and deformation of the light blocking structures 415 due to external impact can be reduced or prevented.The second control element 420 may include variable structures 425 arranged between a second lower control substrate 421 and a second upper control substrate 422. The variable structures 425 may extend in a direction perpendicular to the light blocking structures 415. For example, the variable structures 425 may extend side by side in the second direction Z. A first control electrode 423 may be arranged between the second lower control substrate 421 and the variable structures 425. A second control electrode 424 may be disposed between the variable structures 425 and the second upper control substrate 422. For example, the variable structures 425 may be arranged between the first control electrode 423 and the second control electrode 424. Each of the variable structures 425 may be surrounded by a second control insulating layer 426. The second control insulating layer 426 may include an insulating material. The second control insulating layer 426 may include a transparent material. For example, the second control insulating layer 426 may include the same material as the first control insulating layer 416. The first control electrode 423 may extend between the second lower control substrate 421 and the second control insulating layer 426. The second control electrode 424 may extend between the second control insulating layer 426 and the second upper control substrate 422. The first control electrode 423 and the second control electrode 424 may include a conductive material. For example, the first control electrode 423 and the second control electrode 424 may be a transparent electrode made of a transparent conductive material such as ITO and IZO. A space between the first control electrode 423 and the second control electrode 424 may be completely filled by the variable structures 425 and the second control insulating layer 426. Therefore, in the display device DP according to the aspect of the present disclosure, damage and deformation of the variable structures 425 due to external impact can be reduced or prevented.The transmittance of each of the variable structures 425 may be changed according to a voltage applied to the first control electrode 423 and the second control electrode 424. For example, each of the variable structures 425 may include a transparent fluid 425 fand black particles 425 p. The transparent fluid 425f of each variable structure 425 may be disposed in a space defined by the second control insulating layer 426. The black particles 425 pmay be dispersed in the transparent fluid 425 f. For example, the black particles 425 pmay move freely in the transparent fluid 425 f. The black particles 425 pinclude a material capable of blocking light. The black particles 425 pmay be conductive. For example, the black particles 425 pmay include an electronic ink. Therefore, in the display device DP according to the aspect of the present disclosure, the viewing angle in the first direction X can be selectively limited by the variable structures 425 of the second control element 420.FIGS. 5A and 5B are views showing a propagation direction of light passing through the second control element 420 when a driving voltage is applied to the first control electrode 423 and the second control electrode 424 in the display device DP according to the aspect of the present disclosure. FIGS. 6A and 6B are views showing a propagation direction of light passing through the second control element 420 when a driving voltage is not applied to the first control electrode 423 and the second control electrode 424 in the display device DP according to the aspect of the present disclosure.An operation of the display device DP according to the aspect of the present disclosure will be described with reference to FIGS. 1 to 4, 5A, 5B, 6A, and 6B. First, in the display device DP according to the aspect of the present disclosure, the black particles 425 pof each variable pattern 425 may move to an area of the first control electrode 423 or an area of the second control electrode 424 when a driving voltage is applied to the first control electrode 423 and the second control electrode 424, as shown in FIGS. 1 to 4, 5A, and 5B. Therefore, in the display device DP according to the aspect of the present disclosure, the central portion of each variable structure 425 may become transparent. That is, in the display device DP according to the aspect of the present disclosure, the light L 1 propagating in a direction perpendicular to the upper surface of the light guide plate 220 may pass between the variable structures 425, and the light L 2 propagating in the first direction X may pass through the central portion of each variable structure 425. Therefore, the image realized by the display device DP according to the aspect of the present disclosure can be recognized by the user and persons around the user, for example, the driver who sits on the driver's seat.In the display device DP according to the aspect of the present disclosure, the light guide plate 220 may include a first side 220 a, a second side 220 b, a third side 220 c, and a fourth side 220 d. The second side 220 bmay be perpendicular to the first side 220 a. The third side 220 cmay be opposite to the second side 220 b. The fourth side 220 dmay be opposite the first side 220 a. For example, a planar shape of the light guide plate 220 may be a rectangular shape, e.g., a square shape. The first side 220 aof the light guide plate 220 may extend in the same direction as the light blocking structures 415. For example, the first side 220 aof the light guide plate 220 may extend in the first direction X.The light source element 210 may include a first light source device 210 a, a second light source device 210 b, and a third light source device 210 c. The first light source device 210 amay be disposed on the first side 220 aof the light guide plate 220. The second light source device 210 bmay be disposed on the second side 220 bof the light guide plate 220. The third light source device 210 cmay be disposed on the third side 220 cof the light guide plate 220. In the display device DP according to the aspect of the present disclosure, all of the first light source device 210 a, the second light source device 210 b, and the third light source device 210 cmay emit light when the driving voltage is applied to the first control electrode 423 and the second control electrode 424. Therefore, in the display device DP according to the aspect of the present disclosure, the amount of light L 2 propagating in the first direction X can be increased. Therefore, in the display device DP according to the aspect of the present disclosure, the visibility of an image realized by the display device DP according to the aspect of the present disclosure to persons around the user, for example, the driver, can be improved.In the display device DP according to the aspect of the present disclosure, the black particles 425 pof each variable structure 425 may be freely dispersed in the corresponding transparent fluid 425 fwhen the driving voltage is not applied to the first control electrode 423 and the second control electrode 424, as shown in FIGS. 1 to 4, 6A, and 6B. Therefore, in the display device DP according to the aspect of the present disclosure, each of the variable structures 425 can become entirely an opaque region. That is, in the display device DP according to the aspect of the present disclosure, the light L 2 propagating in the first direction X may be blocked by the variable structures 425. Therefore, the image realized by the display device DP according to the aspect of the present disclosure cannot be recognized by persons around the user, for example, the driver seated in the driver's seat.In the display device DP according to the aspect of the present disclosure, only the first light source device 210 amay emit the light when the driving voltage is not applied to the first control electrode 423 and the second control electrode 424. Therefore, in the display device DP according to the aspect of the present disclosure, the amount of light propagating in the first direction X can be reduced. That is, in the display device DP according to the aspect of the present disclosure, the visibility of the image for persons around the user, for example, the driver, may be reduced. The first side 220 aof the light guide plate 220 may have a length longer than the second side 220 band the third side 220 cof the light guide plate 220. Therefore, in the display device DP according to the aspect of the present disclosure, the decrease in visibility to the user due to the limitation of the viewing angle can be minimized.Accordingly, the display device DP according to the aspect of the present disclosure may include the viewing angle control unit 400 between the backlight unit 200 and the liquid crystal panel 100, wherein the viewing angle control unit 400 may include the light blocking structures 415 extending in the first direction X and the variable structures 425 extending in the second direction Z, wherein each of the variable structures 425 may be controlled by the first control electrode 423 and the second control electrode 424. Therefore, in the display device DP according to the aspect of the present disclosure, the viewing angle can be selectively limited. Therefore, in the display device DP according to the aspect of the present disclosure, accidents due to distraction of people around the user realized from the realized image can be reduced or prevented.And in the display device DP according to the aspect of the present disclosure, the backlight unit 200 may include the light source devices 210 a, 210 b, and 210 con three sides 220 a, 220 b, and 220 cof the light guide plate 220, wherein the second light source device 210 band the third light source device 210 cdisposed on the second side 220 band the third side 220 cof the light guide plate 220 extending in the second direction Z may operate depending on whether or not the driving voltage is applied to the first control electrode 423 and the second control electrode 424. Therefore, in the display device DP according to the aspect of the present disclosure, the limitation of the viewing angle can be effectively performed, and the visibility deviation caused by the change of the viewing angle can be minimized.In the display device DP according to the aspect of the present disclosure, each of the variable structures 425 includes the black particles 425 p. However, a display device according to another aspect of the present disclosure may include the variable structures formed of different materials. For example, in the display device according to another aspect of the present disclosure, the variable structures 427 may include an electrochromic material as shown in FIGS. 7, 8A, and 8B, where FIGS. 8A and 8B are cross-sectional views taken along line I-I' in FIG. 7. The electrochromic material may be a material that changes color according to a voltage applied to the first control electrode 423 and the second control electrode 424. For example, the electrochromic material may include a metal oxide such as tungsten oxide (WO), vanadium oxide (VO), titanium oxide (TiO), and molybdenum oxide (MoO).The variable structures 427 may include first variable structures 427 aextending side by side in the second direction Z and second variable structures 427 bextending side by side in the first direction X perpendicular to the second direction Z. The first variable structures 427 aand the second variable structures 427 bmay be colored simultaneously. For example, the first variable patterns 427 aand the second variable patterns 427 bmay not be colored when no voltage is applied to the first control electrode 423 and the second control electrode 424, as shown in FIG. 8A. The first variable patterns 427 aand the second variable patterns 427 bmay be colored black when a voltage is applied to the first control electrode 423 and the second control electrode 424, as shown in FIG. 8B. Therefore, in the display device according to another aspect of the present disclosure, the selective limitation of the viewing angle can be effectively performed. That is, in the display device according to another aspect of the present disclosure, the light propagating to persons around the user, for example, the driver, can be effectively blocked by the colored variable structures 427.In the display device according to another aspect of the present disclosure, the first control electrode 423 may include first electrode patterns 423 aand second electrode patterns 423 b. The first electrode structures 423 amay extend side by side in the second direction Z. Each of the first electrode structures 423 amay overlap one of the first variable structures 427 a. For example, each of the first electrode patterns 423 amay have a horizontal width equal to that of the corresponding first variable pattern 427 a. The second electrode structures 423 bmay extend side by side in the first direction X. Each of the second electrode structures 423 bmay overlap one of the second variable structures 427 b. For example, each of the second electrode patterns 423 bmay have a horizontal width equal to that of the corresponding second variable pattern 427 b. The first electrode structures 423 aand the second electrode structures 423 bmay include a conductive material. The second electrode structures 423 bmay be insulated from the first electrode structures 423 a. For example, an electrode insulating layer 428 may be disposed between the first electrode structures 423 aand the second electrode structures 423 b. The electrode insulating layer 428 may include an insulating material. The electrode insulating layer 428 may include an inorganic material such as silicon oxide (SiO) and silicon nitride (SiN). The second electrode patterns 423 bmay be disposed between the second lower control substrate 421 and the electrode insulating layer 428. The first electrode patterns 423 amay be disposed on the electrode insulating layer 428. For example, each of the second electrode structures 423 bmay cross the first electrode structures 423 a. Therefore, in the display device according to another aspect of the present disclosure, a voltage may be applied to the first electrode patterns 423 aor the second electrode patterns 423 b. For example, in the display device according to another aspect of the present disclosure, the first variable structures 427 aor the second variable structures 427 bmay be colored. Therefore, in the display device according to another aspect of the present disclosure, the degree of freedom for a method of limiting the viewing angle can be improved.In the display device according to the aspect of the present disclosure, the viewing angle control unit 400 has a stacked structure of the first control member 410 and the second control member 420. However, in a display device according to another aspect of the present disclosure, the viewing angle control unit may have a different structure. For example, in the display device according to another aspect of the present disclosure, light blocking structures 551 and variable structures 552 of a viewing angle control unit 500 disposed between the backlight unit 200 and the liquid crystal panel 100 may be disposed between a first control substrate 510 and a second control substrate 520, as shown in FIGS. 9, 10, 11A, and 11B, where FIGS. 11A and 11B are cross-sectional views taken along line II-II' in FIG. 10. A first control electrode 530 may be disposed on a surface of the first control substrate 510 that is opposite to the second control substrate 520. A second control electrode 540 may be disposed on a surface of the second control substrate 520 that is opposite to the first control substrate 510. The light blocking structures 551 and the variable structures 552 may be disposed between the first control electrode 530 and the second control electrode 540. The light blocking structures 551 and the variable structures 552 may be surrounded by a control insulating layer 560. For example, a space between the first control electrode 530 and the second control electrode 540 may be completely filled by the light blocking structures 551, the variable structures 552, and the control insulating layer 560.The light blocking structures 551 may extend in the first direction X. The variable structures 552 may extend in the second direction Z perpendicular to the first direction X. Each of the variable structures 552 may not cross the light blocking structures 551. For example, each of the variable structures 552 may be disposed between the light blocking structures 551.The light blocking structures 551 may limit the angle of view in the second direction Z regardless of whether or not the driving voltage is applied to the first control electrode 530 and the second control electrode 540. The transmittance of each variable pattern 552 may be changed depending on whether the driving voltage is applied to the first control electrode 530 and the second control electrode 540. For example, the viewing angle in the first direction X may be limited by the variable structures 552 when the driving voltage is not applied to the first control electrode 530 and the second control electrode 540. Therefore, in the display device according to another aspect of the present disclosure, the degree of freedom for the configuration of the viewing angle control unit 500 can be improved.As a result, the display device according to aspects of the present disclosure may include the viewing angle control unit between the backlight unit and the liquid crystal panel, wherein the viewing angle control unit includes the light blocking structures extending in the first direction and the variable structures extending in the second direction perpendicular to the first direction, and wherein the transmittance of each variable structure may be changed according to the voltage applied to the first control electrode and the second control electrode. Therefore, in the display device according to aspects of the present disclosure, the viewing angle can be selectively limited by the variable structures. Thereby, in the display device according to aspects of the present disclosure, accidents caused by distraction of people around the user can be reduced or prevented.

Claims

A display device (DP) comprising: a backlight unit (200); a liquid crystal panel (100) disposed on the backlight unit (200); and a viewing angle control unit (400, 500) disposed between the backlight unit (200) and the liquid crystal panel (100), wherein the viewing angle control unit (400, 500) comprises light blocking structures (415, 551) having a light blocking material and variable structures (425, 552) disposed between a first control electrode (423, 530) and a second control electrode (424, 540), wherein the variable structures (425, 552) extend in a direction perpendicular to the light blocking structures (415, 551), and wherein a transmittance of each variable structure (425, 552) according to a transmittance to the first control electrode (423, 530) and the second control electrode (424, 540), wherein the light blocking structures (415, 551) are arranged between the first control electrode (423, 530) and the second control electrode (424, 540).The display device (DP) according to claim 1, wherein the light blocking material comprises a black dye.The display device (DP) according to claim 1 or 2, wherein each of the variable structures (425, 552) includes a transparent fluid (425f) and black particles (425p) dispersed in the transparent fluid (425f).The display device (DP) according to claim 3, wherein the viewing angle control unit (400, 500) further comprises a control insulating layer (426, 560) surrounding each variable pattern (425, 552).The display device (DP) according to any one of claims 1 to 4, wherein the backlight unit (200) comprises a light guide plate (220) and a light source element (210), wherein the light guide plate (220) comprises a second side (220b) perpendicular to a first side (220a), a third side (220c) opposite to the second side (220b), and a fourth side (220d) opposite to the first side (220a), and wherein the light source element (210) comprises a first light source device (210a) on the first side (220a) of the light guide plate (220), a second light source device (210b) on the second side (220b) of the light guide plate (220), and a third light source device (210c) on the third side (220c) of the light guide plate (220).The display device (DP) according to claim 5, wherein the first side (220a) of the light guide plate (220) extends in a same direction as the light blocking structures (415, 551).The display device (DP) according to claim 5 or 6, wherein the first side (220a) of the light guide plate (220) has a length longer than the second side (220b) and the third side (220c) of the light guide plate (220).A display device (DP) comprising: a backlight unit (200); a viewing angle control unit (400, 500) disposed on the backlight unit (200); and a liquid crystal panel (100) disposed on the viewing angle control unit (400, 500), wherein the viewing angle control unit (400, 500) comprises light blocking structures (415, 551) extending in a first direction (X) and first variable structures (427a, 552) extending in a second direction (Z) perpendicular to the first direction (X), wherein the first variable structures (427a, 552) are disposed between a first control electrode (423, 530) and a second control electrode (424, 540), and wherein each of the first variable structures (427a, 552) comprises an electrochromic material, wherein the light blocking structures (415, 551) are arranged between the first control electrode (423, 530) and the second control electrode (424, 540).The display device (DP) according to claim 8, wherein each of the first variable structures (427a, 552) comprises a metal oxide.The display device (DP) according to claim 8 or 9, wherein the first control electrode (423, 530) includes first electrode patterns (423a) extending side by side in the second direction (Z), and wherein each of the first variable patterns (427a, 552) overlaps with one of the first electrode patterns (423a).The display device (DP) according to claim 10, wherein each of the first variable structures (427a, 552) has a same horizontal width as a corresponding first electrode structure (423a).The display device (DP) according to claim 10 or 11, wherein the viewing angle control unit (400, 500) includes a lower control substrate (421, 510) and an upper control substrate (422, 520) disposed between the backlight unit (200) and the liquid crystal panel (100), and wherein the first control electrode (423, 530), the first variable structures (427a, 552), and the light blocking structures (415, 551), and the second control electrode (424, 540) are sequentially stacked between the lower control substrate (421, 510) and the upper control substrate (422, 520).The display device (DP) according to claim 12, wherein the viewing angle control unit (400, 500) further comprises a control insulating layer (426, 560) disposed between the first variable structures (427a, 552) and the light blocking structures (415, 551).

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