Display device

Abstract

A display device includes: a display panel configured to display an image; a first backlight unit located below the display panel, the first backlight unit being configured to output first light and including a first light guide plate, the first light guide plate including a plurality of first patterns protruding or recessed from a rear surface of the first light guide plate; and a second backlight unit located between the display panel and the first backlight unit, the second backlight unit being configured to output second light and including a second light guide plate, the second light guide plate including a plurality of second patterns protruding from a rear surface of the second light guide plate, the second patterns having an asymmetrical cone shape.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2021-0128552, filed on September 29, 2021, the entire disclosure of which is incorporated herein by reference for all purposes. Technical Field

[0003] The present invention relates to a display device, and more specifically, to a display device having a limited viewing angle. Background Technology

[0004] With the development of the information society, various display devices are being developed. Recently, various display devices such as liquid crystal displays (LCDs), plasma display panels (PDPs), and organic light-emitting diodes (OLEDs) have been adopted.

[0005] Traditional display devices do not typically require viewing angle restrictions. However, recently, due to privacy and information protection concerns, it has become necessary to restrict the viewing angle of display devices. For example, when a display device is used as an information medium inside a vehicle to provide high-definition images to passengers in their seats, it is necessary to restrict the driver's viewing angle for safe driving. Summary of the Invention

[0006] The implementation provides a display device that can effectively limit the viewing angle.

[0007] The display device according to an embodiment may include: a display panel configured to display an image; a first backlight unit located below the display panel, the first backlight unit being configured to output first light and including a first light guide plate, the first light guide plate including a plurality of first patterns protruding or recessed from the rear surface of the first light guide plate; and a second backlight unit located between the display panel and the first backlight unit, the second backlight unit being configured to output second light and including a second light guide plate, the second light guide plate including a plurality of second patterns protruding from the rear surface of the second light guide plate, the second patterns having an asymmetrical cone shape.

[0008] In one embodiment, a display device disposed in a vehicle includes: a display panel configured to display an image; a first backlight unit including a first light source package located below the display panel and a first light guide plate located on one side of the first light source package, the first backlight unit being configured to generate first light; and a second backlight unit including a second light source package located between the display panel and the first backlight unit and a second light guide plate located on one side of the second light source package, the second backlight unit being configured to generate second light, wherein the second light guide plate includes a plurality of second patterns protruding from the rear surface of the second light guide plate, the second patterns having an asymmetrical cone shape.

[0009] In one embodiment, a display device includes: a display panel configured to display an image; a first backlight unit located below the display panel, the first backlight unit being configured to output a first light to the display panel; and a second backlight unit located between the display panel and the first backlight unit, wherein the display panel, the first backlight unit, and the second backlight unit overlap each other, wherein during a first mode of the display device, the first backlight unit is enabled and the second backlight unit is disabled, such that an image is displayed at a first side view; and wherein during a second mode of the display device, the first backlight unit is enabled and the second backlight unit is enabled, such that an image is displayed at a second side view greater than the first side view. Attached Figure Description

[0010] Figure 1 This is an exploded perspective view of the display device according to an embodiment.

[0011] Figure 2 This is a schematic diagram illustrating the implementation method. Figure 1 The rear view of the structure of the first light guide plate shown.

[0012] Figure 3 It is a schematic view illustrating a pattern formed on the lower surface of the first light guide plate according to an embodiment.

[0013] Figure 4 This is a schematic diagram illustrating the implementation method. Figure 1 The rear view of the structure of the second light guide plate shown.

[0014] Figure 5 and 6 It is a schematic diagram of a pattern formed on the lower surface of the second light guide plate according to an embodiment.

[0015] Figure 7 This is a schematic diagram illustrating the light path passing through the first light guide plate in a first mode of the display device according to an embodiment.

[0016] Figure 8 This is a schematic diagram illustrating the light path passing through the second light guide plate in a second mode of the display device according to an embodiment.

[0017] Figure 9 The results are simulations obtained by measuring the brightness distribution in the first and second modes of the display device according to the embodiment.

[0018] Figure 10 It is a graph showing the brightness distribution in the first and second modes of the display device according to the embodiment.

[0019] Figure 11 This is a view illustrating an example of the application of a display device according to an embodiment. Detailed Implementation

[0020] In the following description, embodiments will be described with reference to the accompanying drawings. In this specification, when a component (or region, layer, portion, etc.) is referred to as being "on" or "connected to" or "joined to" another component, it means that the component may be directly disposed on or directly connected to or joined to the other component, or there may be a third component between them.

[0021] Similar reference numerals refer to similar elements. Furthermore, in the accompanying drawings, the thickness, scale, and dimensions of the components are enlarged for the purpose of effectively illustrating the technical content. Additionally, the term "and / or" includes any combination of one or more of the associated configurations.

[0022] Various elements may be described using terms such as "first" and "second," but these elements are not limited by these terms. The terms mentioned above are only used to distinguish one component from other components. For example, without departing from the scope of embodiments of the invention, a first component may be referred to as a second component; similarly, a second component may also be referred to as a first component.

[0023] Terms such as “lower,” “below,” “above,” and “upper” are used to describe the relationships between the components shown in the diagram. These terms are relative concepts and are described based on the directions indicated in the diagram.

[0024] Terms such as “comprising” or “having” are intended to indicate the presence of the features, quantities, steps, operations, components, parts or combinations thereof described in the specification, but should not be construed as excluding the possibility of the presence or addition of one or more other features, quantities, steps, operations, components, parts or combinations thereof.

[0025] Figure 1 This is an exploded perspective view of the display device according to an embodiment. Figure 2 This is a schematic diagram illustrating the implementation method. Figure 1 The rear view of the structure of the first light guide plate shown. Figure 3 It is a schematic view illustrating a pattern formed on the lower surface of the first light guide plate according to an embodiment. Figure 4 This is a schematic diagram illustrating the implementation method. Figure 1 The rear view of the structure of the second light guide plate shown. Figure 5 and 6 It is a schematic diagram of a pattern formed on the lower surface of the second light guide plate according to an embodiment.

[0026] Reference Figure 1 The display device 1 according to the embodiment may include: a display panel 110 for displaying an image comprising a plurality of pixels; and a first backlight unit 120 and a second backlight unit 130 disposed on the rear surface of the display panel 110 to emit light toward the front of the display panel 110. Figure 1 As shown, the display panel 110, the first backlight unit 120, and the second backlight unit 130 overlap each other. Although not shown, the display device 1 may also include a panel guide, a top cover, a bottom cover, etc., for accommodating and fixing the display panel 100 and the first backlight unit 120 and the second backlight unit 130.

[0027] The display panel 110 is a liquid crystal panel and may include a lower substrate and an upper substrate that are bonded to each other facing each other, and a liquid crystal layer inserted between the upper substrate and the lower substrate.

[0028] The lower substrate may include: gate lines and data lines arranged intersecting each other; and liquid crystal cells formed in the regions where the gate lines and data lines intersect. In one embodiment, the liquid crystal cells may be arranged in a matrix on the lower substrate. Each liquid crystal cell may include: a thin-film transistor disposed at the intersection region of the gate lines and data lines; and a pixel electrode that receives a data voltage applied to the data lines via the thin-film transistor when the thin-film transistor is turned on.

[0029] On the upper substrate, color filters for realizing multiple colors including red, green and blue can be formed; and a black matrix for dividing the color filters and blocking light passing through the liquid crystal layer and the common electrode for applying voltage to the liquid crystal layer.

[0030] The common electrode can be formed on the upper substrate in a vertical electric field driving manner such as twisted nematic (TN) mode and vertical orientation (VA) mode, and can be formed on the lower substrate together with the pixel electrode in a horizontal electric field driving manner such as in-plane switching (IPS) mode and edge field switching (FFS) mode.

[0031] The amount of light transmitted from the display panel 110 is adjusted by driving the liquid crystal cell through an electric field generated by the potential difference between the data voltage supplied to the pixel electrode via the data line and the common voltage supplied to the common electrode.

[0032] The first backlight unit 120 and the second backlight unit 130 are disposed below the display panel 110 to provide light to the display panel 110. The first backlight unit 120 may be disposed below the display panel 110, and the second backlight unit 130 may be inserted between the first backlight unit 120 and the display panel 110.

[0033] The first backlight unit 120 may include a first light source package 121, a first light guide plate 122, a first diffuser 123, a first prism sheet 124, and a first light control film 125.

[0034] The first light source package 121 can be driven by receiving power from an external source and generating light. The first light source package 121 can generate light using various light sources such as cold cathode fluorescent lamps (CCFLs), external electrode fluorescent lamps (EEFLs), hot cathode fluorescent lamps (HCFLs), or light-emitting diodes (LEDs). The first light source package 121 is configured to face at least one side of the first light guide plate 122. Therefore, light emitted from the first light source package 121 can be incident on one side of the first light guide plate 122.

[0035] The first light guide plate 122 is positioned facing the side of the first light source package 121 and guides light incident from the first light source package 121 to emit it onto the upper surface. The first light guide plate 122 may be disposed on at least one side of the first light source package 121. In embodiments, the first light guide plate 122 is a light-transmitting material and may be made, for example, of a plastic material such as polymethyl methacrylate (PMMA) or a material selected from polycarbonate (PC) type materials. However, the material of the first light guide plate 122 is not limited to the above-mentioned materials, and the first light guide plate 122 may be made of other materials.

[0036] Reference Figure 2 and Figure 3 Each of the first patterns 122a, which are polygonal and can be either protruding or recessed, can be formed on the rear surface of the first light guide plate 122. The first patterns 122a can be embossed onto the rear surface of the first light guide plate 122 by injection or printing. In another embodiment, the first patterns 122a can be formed as intaglio shapes recessed into the rear surface of the first light guide plate 122. The first patterns 122a can be arranged to be regularly or irregularly spaced from each other.

[0037] In an embodiment, the first pattern 122a may have a pyramidal shape. In this case, the first pattern 122a may have a symmetrical shape, wherein the slopes of the four sides (or lateral portions) forming the pyramid are the same or substantially similar. In an embodiment, the length L1 of one side of the symmetrical pyramid may be approximately 10 μm to 50 μm, for example, approximately 30 μm. Furthermore, in an embodiment, the angle α between the rear surface of the first light guide plate 122 and one side of the symmetrical pyramid is approximately 20° to 60°, for example, approximately 40°. The apex angle b of the symmetrical pyramid may be approximately 100°. The height h1 of the symmetrical pyramid may be determined based on the dimensions and slopes of the four sides, for example, it may be 5 μm to 30 μm. However, embodiments of the present invention are not limited thereto.

[0038] In another embodiment, the first pattern 122a may have a dot shape. In one embodiment, the diameter of the dot may be approximately 40 μm to 100 μm, and the depth of the dot may be approximately 2 μm to 30 μm. However, embodiments of the present invention are not limited thereto.

[0039] The emission angle of light incident from the first light source package 121 onto the first light guide plate 122 can be controlled by the first pattern 122a formed on the rear surface. Since the first pattern 122a has a symmetrical cone shape or dot shape, the light refracted on the four sides or curved surface of the first pattern 122a can be emitted in the lateral direction in addition to being emitted onto the upper surface of the first light guide plate 122.

[0040] A first diffuser 123 and a first prism sheet 124 are disposed on the first light guide plate 122. The first diffuser 123 diffuses light emitted from the first light guide plate 122 to improve brightness uniformity based on viewing angle. The first diffuser 123 may be formed of PET or polycarbonate (PC) resin and may include a particulate coating layer as a diffuser. The first prism sheet 124 focuses light such that the propagation direction of light emitted from the first light guide plate 122 or the first diffuser 123 is close to the normal direction of the display panel 110, thereby improving the front brightness of the display panel 100. In one embodiment, the first prism sheet 124 may include a first upper prism sheet 124a and a first lower prism sheet 124b, wherein prism patterns are formed and the axes of the prism patterns are arranged orthogonally to each other.

[0041] A first light control film (LCF) 125 is disposed on the first prism sheet 124. The first light control film 125, together with the first pattern 122a, can control the profile of the light emitted by the first backlight unit 120. For example, the first light control film 125 can adjust the left-right and / or vertical viewing angle of the light emitted from the first backlight unit 120 to be narrower.

[0042] The second backlight unit 130 is disposed on the first backlight unit 120. The second backlight unit 130 may include a second light source package 131, a second light guide plate 132, and a second light control film 133.

[0043] The second light source package 131 can be driven by receiving power from an external source and generating light. The second light source package 131 utilizes various light sources such as cold cathode fluorescent lamps (CCFLs), external electrode fluorescent lamps (EEFLs), hot cathode fluorescent lamps (HCFLs), or light-emitting diodes (LEDs) to generate light. The second light source package 131 is configured to face at least one side of the second light guide plate 132. Therefore, light emitted from the second light source package 131 can be incident on this side of the second light guide plate 132.

[0044] In some embodiments, the second light source package 131 may be disposed on a side different from the first light source package 131. For example, when the first light source package 121 is disposed on the first side of the display device 1, the second light source package 131 may be disposed on at least one of the second to fourth sides of the display device 1. For example, the second light source package 131 may be disposed on the left / right side, only the left side, or only the right side of the display device 1. Furthermore, the number of second light source packages 131 may be the same as or different from the number of first light source packages 121. For example, when one first light source package 121 is disposed as shown, two or more second light source packages 131 may be disposed. In this embodiment, two or more second light source packages 131 may be disposed facing each other with the second light guide plate 132 inserted therebetween, but the embodiments of the present invention are not limited thereto.

[0045] The second light guide plate 132 is configured to face the second light source package 131 and guide light incident from the second light source package 131 to emit it onto its upper surface. The second light guide plate 132 may be disposed on at least one side of the second light source package 131. In embodiments, the second light guide plate 132 is a light-transmitting material and may be made, for example, of a plastic material such as polymethyl methacrylate (PMMA) or a material selected from polycarbonate (PC) type materials.

[0046] Reference Figure 4 and Figure 5Each of the second patterns 132a, which are polygonal and protruding or recessed, can be formed on the rear surface of the second light guide plate 132. The second patterns 132a can be embossed on the rear surface of the second light guide plate 132 by injection or printing. The second patterns 132a can be arranged to be regularly or irregularly spaced from each other.

[0047] In one embodiment, the second pattern 132a may have a cone shape. In this case, the second pattern 132a may have an asymmetrical shape, wherein at least some of the slopes of the four sides forming the cone have different angles. In this embodiment, in the second pattern 132a, the slope of the first side S1 away from the second light source package 131 may be steeper than the slope of the second side S2 closer to the second light source package 131.

[0048] In other words, the angle d between the first side S1 of the second pattern 132a, which is away from the second light source package 131, and the rear surface of the second light guide plate 132 is greater than the angle c between the second side S2 of the second pattern 132a, which is close to the second light source package 131, and the rear surface of the second light guide plate 132. In this case, if the slope is steep, the acute angle between the normal of the corresponding side (here, the first side S1) and the rear surface of the second light source package 131 can be less than 45 degrees (approximately horizontal). Conversely, if the slope is gentle, the acute angle between the normal of the corresponding side (here, the second side S2) and the rear surface of the second light source package 131 can be greater than 45 degrees (approximately vertical).

[0049] In one embodiment, the length of one side of the asymmetric cone can be approximately 20 μm to 100 μm; for example, the length of the long side L2 can be approximately 50 μm, and the length of the short side L3 can be approximately 30 μm. Furthermore, in this embodiment, the angles c and d between the rear surface of the second light guide plate 132 and the four sides of the asymmetric cone are approximately 20° to 60°, for example, approximately 50° to 60°. The apex angle e of the asymmetric cone can be approximately 60° to 80°. The height h2 of the asymmetric cone can be determined based on the dimensions and slope of the four sides, for example, it can be 5 μm to 30 μm. However, the embodiments of the present invention are not limited thereto. In one embodiment, the slope of the four inclined surfaces of each second pattern can be in the range of 5° to 60°. In one embodiment, the length of the long side of each second pattern can be in the range of 1 μm to 100 μm, and the height of the long side of each second pattern can be in the range of 1 μm to 50 μm.

[0050] Reference Figure 6The ratio of the length L2 of the long side to the height h2 of the second pattern 132a can be set to be in the range of approximately 0.5 to 20. For example, the ratio of the length L2 of the long side to the height h2 of the second pattern 132a can be set to 100:14.2. Furthermore, the ratio of the distance L4 from the perpendicular foot of the second pattern 132a from the top to the bottom to one short side to the distance L5 to the other short side can be set to approximately 0.4. As an example, the ratio of the distance L4 from the perpendicular foot of the second pattern 132a from the top to the bottom to one short side to the distance L5 to the other short side can be approximately 1:9 to 5:5, preferably 3:7. However, embodiments of the present invention are not limited to this.

[0051] A second light control film 133 is disposed on the second light guide plate 132. The second light control film 133, together with the second pattern 132a, can control the profile of the light emitted from the second backlight unit 130. For example, the second light control film 133 can adjust the left-right and / or vertical viewing angle of the light emitted from the second backlight unit 130 to a narrower viewing angle. In various embodiments, optical films such as UV blocking films (LAF) may be further provided or omitted.

[0052] The following describes a specific implementation of controlling the side viewing angle of the display device 1 through the backlight units 120 and 130 having the above-described structure.

[0053] Figure 7 This is a schematic diagram illustrating the light path through the first light guide plate 122 in the first mode of the display device 1 according to the embodiment. Figure 8 This is a schematic diagram illustrating the light path through the second light guide plate 132 in the second mode of the display device 1 according to the embodiment. Figure 9 The results are simulations obtained by measuring the brightness distribution in the first and second modes of the display device according to the embodiment. Figure 10 It is a graph showing the brightness (nit) distribution in the first and second modes of the display device according to the embodiment.

[0054] The display device 1 according to the embodiment can operate in either a first mode or a second mode. For example, the first mode is a private mode, and may be a mode for limiting the side viewing angle of the display device 1. Furthermore, the second mode is a sharing mode, and may be a mode that does not limit the side viewing angle of the display device 1. That is, the side viewing angle in the second mode may be greater than the side viewing angle in the first mode. Therefore, the sharing mode has a greater viewing angle than the private mode.

[0055] Refer to together Figure 1In private mode, the first light source package 121 of the first backlight unit 120 is turned on, and the second light source package 131 of the second backlight unit 130 is turned off. Therefore, in private mode, the first backlight unit 120 is enabled, and the second backlight unit 130 is disabled.

[0056] Reference Figure 7 The emission angle of the light emitted from the first light source package 121 is controlled by a first pattern 122a formed on the rear surface of the first light guide plate 122, and the light is emitted onto the upper surface of the first light guide plate 122. That is, the light emitted from the first light source package 121 can be guided to the lower surface of the second light guide plate 122 through the inclined or curved surface of the first pattern 122a. The light emitted onto the upper surface of the first light guide plate 122 passes through the first diffuser 123, the first prism sheet 124, and the first light control film 125, and is incident on the rear surface of the second backlight unit 130.

[0057] The emission angle of light incident on the rear surface of the second backlight unit 130 is controlled by a second pattern 132a formed on the rear surface of the second light guide plate 132. Since the second pattern 132a has an asymmetrical cone shape, the light incident on the second light guide plate 132 can be controlled to be emitted at a narrower angle to the upper surface of the second light guide plate 132, or it can be controlled to be emitted in the lateral direction.

[0058] For example, when the second light source package 131 is closed, light emitted from the first backlight unit 120 can be incident on the second light guide plate 132. Light incident on the rear surface (or lower surface) of the second light guide plate 132 can be refracted on the inclined surface (or second edge) of the second pattern 132a, and then emitted in an upward direction substantially perpendicular to the upper surface of the second light guide plate 132. In particular, light incident on the rear surface of the second light guide plate 132 has an emission angle further restricted to a narrower angle due to the gently inclined surface of the second pattern 132a.

[0059] More specifically, the light incident on the rear surface of the second light guide plate 132 reaches a greater extent than the second side S2, which has a relatively large area in the second pattern 132a. Since the normal of the second side S2 has an angle greater than 45 degrees (generally perpendicular) relative to the rear surface of the second light guide plate 132, the light incident on the rear surface propagates generally perpendicularly to the rear surface according to the normal direction of the second side S2. That is, the light incident on the rear surface is emitted substantially perpendicular to the rear surface (or lower surface) of the second light guide plate 132. As a result, for the light incident on the rear surface, lateral emission is restricted, and the emission angle is restricted only in the direction perpendicular to the upper surface of the second light guide plate 132, thus limiting the emission angle to a narrower angle.

[0060] Therefore, when the emission angle is controlled to be narrower by the second pattern 132a, the viewing angle from one side of the display device 1 is limited, and the display device 1 can operate in the first mode, i.e., the private mode.

[0061] Light emitted from the second backlight unit 130 is applied to the display panel 110, and an image is output in the upward direction of the display device 1 through pixels disposed on the display panel 110. Since the emission angle of the light emitted from the second backlight unit 130 is limited to the upward direction, the image output through the display panel 110... Figure 9 and 10 The image is highly bright in the forward direction, and the display is limited in the lateral direction. Therefore, since the lateral viewing angle of the display panel 110 is controlled in private mode, the image will not be viewed by a user viewing the display panel 110 from the side.

[0062] In the shared mode, the first light source package 121 of the first backlight unit 120 is turned on, and the second light source package 131 of the second backlight unit 130 is also turned on. Therefore, in the shared mode, the first backlight unit 120 is enabled, and the second backlight unit 130 is also enabled.

[0063] Reference Figure 8 The light emitted from the first light source package 121 has an emission angle controlled by a first pattern 122a formed on the rear surface of the first light guide plate 122, and the light is emitted onto the upper surface of the first light guide plate 122. The light emitted onto the upper surface of the first light guide plate 122 passes through the first diffuser 123, the first prism sheet 124, and the first light control film 125, and then incident on the rear surface of the second backlight unit 130.

[0064] For reference Figure 7 As described, the emission angle of light incident on the rear surface of the second backlight unit 130 is controlled by a second pattern 132a formed on the rear surface of the second light guide plate 132. Light incident on the rear surface of the second backlight unit 130 can be confined to the lateral direction by the gently sloping surface of the second pattern 132a, and can be emitted only at a narrower angle in the upward direction.

[0065] In the shared mode, since the second light source package 131 is open, the light emitted from the second light source package 131 is further incident on the side surface of the second light guide plate 132. This light incident in the lateral direction of the second light guide plate 132 is refracted at the first edge S1 of the second pattern 132a, and at least a portion of the light is emitted laterally relative to the upper surface of the second light guide plate 132, thereby increasing the viewing angle at the side surface of the display device 1.

[0066] More specifically, light incident in the lateral direction on the second light guide plate 132 reaches the first side S1 of the second pattern 132a arranged opposite to each other. Since the normal of the first side S1 has an angle of less than 45° (generally horizontal) with respect to the rear surface of the second light guide plate 132, the sidelight incident adjacent to the normal of the first side S1 is emitted again adjacent to the normal of the first side S1.

[0067] Since the normal of the first side S1 has an angle of less than 45° (generally horizontal) relative to the rear surface of the second light guide plate 132, the light incident on the side surface propagates generally horizontally relative to the rear surface according to the normal direction of the first side S1. That is, the light incident on the side surface is emitted in the lateral direction relative to the rear surface (or lower surface) of the second light guide plate 132. As a result, the light incident on the side surface is allowed to be emitted in the lateral direction, and the emission angle is increased to a wider angle.

[0068] As described above, when the emission angle is controlled to a wider range via the second pattern 132a, the display device 1 can operate in the second mode, i.e., the sharing mode. In the sharing mode, the emission angle can range from 0 to 88°, but is not limited to this.

[0069] Light emitted from the second backlight unit 130 is applied to the display panel 110, and an image is output from the display device 1 in the upward and lateral directions through pixels disposed on the display panel 110. Since the light emitted from the second backlight unit 130 is transmitted in the upward and lateral directions, the image output from the display panel 110 is as follows: Figure 9 and 10 The display panel 110 exhibits high brightness not only in the forward direction but also in the lateral direction. As described above, since the side viewing angle of the display panel 110 is enabled in the shared mode, the image can be viewed by a user viewing the display panel 110 from the side.

[0070] The foregoing described an embodiment in which the first backlight unit 120 is turned on in a first mode and a second mode, and the second backlight unit 130 is turned on in the second mode. However, the invention is not limited thereto. For example, in other embodiments, the first backlight unit 120 may be turned off in at least one of the first mode and the second mode, and the second backlight unit 130 may be turned on in the first mode and turned off in the second mode. In various embodiments, the first backlight unit 120 and the second backlight unit 130 may be controlled in various ways.

[0071] Figure 11 This is a view illustrating an example of the application of a display device according to an embodiment.

[0072] Reference Figure 11The display device 1 according to the embodiment can be installed inside the vehicle. The display device 1 can be integrated or detachably installed on the vehicle's dashboard.

[0073] Display device 1 can display a graphical user interface (GUI) corresponding to navigation, video content, and sound content according to the driving state and / or user request.

[0074] In this embodiment, the display device 1 can operate in a private mode while the vehicle is being driven. For example, the display device 1 can operate in private mode when displaying images, such as moving images, that are determined to interfere with the user's driving. In this embodiment, the display device 1 can control the second light source package 131 to turn off to limit the side viewing angle of the driver's seat.

[0075] In one embodiment, the display device 1 can operate in a sharing mode when the vehicle is not being driven. Alternatively, the display device 1 can operate in a sharing mode even when the vehicle is being driven. For example, the display device 1 can operate in a sharing mode while displaying images determined to assist the user's driving, such as navigation. In this embodiment, the display device 1 can control the second light source package 131 to open up the side view of the driver's seat.

[0076] According to the embodiment, the display device can effectively control the viewing angle by forming an asymmetrical cone pattern on the lower surface of the light guide plate of the upper backlight unit in a backlight in which multiple layers of light guide plates are stacked.

[0077] The display device according to the embodiment can improve the cut-off efficiency for limiting viewing from the driver's seat direction, and can provide viewing of the image with improved brightness in the driver's seat direction as needed.

[0078] The display device according to the embodiment can control the range of viewing angle and improve blocking efficiency by adjusting the size, height and side viewing angle of the pattern having an asymmetrical cone shape.

[0079] Those skilled in the art will understand that the invention can be implemented in other specific forms without altering the technical concept or essential features of the invention. Therefore, it should be understood that the above embodiments are exemplary in all respects and not restrictive. The scope of the invention is defined by the appended claims rather than the detailed description above, which should be interpreted as including all changes or modifications made in accordance with the meaning and scope of the appended claims and their equivalents within the scope of the invention.

Claims

1. A display apparatus comprising: a display panel configured to display an image; a first backlight unit located below the display panel, the first backlight unit configured to output first light and comprising a first light guide plate including a plurality of first patterns protruding or recessed from a rear surface of the first light guide plate; and a second backlight unit located between the display panel and the first backlight unit, the second backlight unit configured to output second light and comprising a second light guide plate including a plurality of second patterns protruding from a rear surface of the second light guide plate, the second patterns having an asymmetric pyramidal shape, wherein the second backlight unit further comprises: a second light source package configured to generate the second light, wherein the second light guide plate is disposed on at least one side of the second light source package, the second light guide plate configured to guide the second light incident from the second light source package to the display panel, wherein among four edges of the asymmetric pyramidal shape of each of the second patterns, an angle between a first edge distal from the second light source package and the rear surface of the second light guide plate is greater than an angle between a second edge proximal to the second light source package and the rear surface of the second light guide plate. 2.The display apparatus of claim 1, wherein the first backlight unit further comprises: a first light source package generating the first light, wherein the first light guide plate is disposed on at least one side of the first light source package and configured to guide the first light incident from the first light source package to the second backlight unit, wherein the first patterns have a symmetric pyramidal shape or a dot shape. 3.The display apparatus of claim 2, wherein one side or a curved surface of the first patterns is configured to guide the first light emitted from the first light source package to the rear surface of the second light guide plate, the first light incident on a lower surface of the second light guide plate is refracted at a second edge of the second patterns and emitted in an upward direction substantially perpendicular to an upper surface of the second light guide plate. 4.The display apparatus of claim 2, wherein the second light emitted from the second light source package is refracted at a first edge of the second patterns, the refracted second light having at least a portion laterally emitted with respect to the upper surface of the second light guide plate. 5.The display apparatus of claim 1, wherein a slope of four inclined surfaces of each of the second patterns is in an angle range of 5° to 60°. 6.The display apparatus of claim 1, wherein a length of a long edge of each of the second patterns is in a range of 1 μm to 100 μm, and a height of the long edge of each of the second patterns is in a range of 1 μm to 50 μm. 7.The display apparatus of claim 1, wherein a ratio of a distance to one short edge to a distance to another short edge, measured from a foot of each of the second patterns from top to bottom, is in a ratio range of 1:9 to 5:

5. 8.The display apparatus of claim 2, wherein the second light source package is disposed on a different side from the first light source package. 9.A display apparatus disposed in a vehicle, the display apparatus comprising: a display panel configured to display an image; a first backlight unit including a first light source package positioned below the display panel and a first light guide plate positioned on a side of the first light source package, the first backlight unit configured to generate first light; and a second backlight unit including a second light source package positioned between the display panel and the first backlight unit and a second light guide plate positioned on a side of the second light source package, the second backlight unit configured to generate second light, wherein the second light guide plate includes a plurality of second patterns protruding from a rear surface of the second light guide plate, the second patterns having an asymmetric pyramidal shape, wherein among four edges of the asymmetric pyramidal shape of each of the second patterns, an angle between a first edge distal from the second light source package and the rear surface of the second light guide plate is greater than an angle between a second edge proximal to the second light source package and the rear surface of the second light guide plate. 10.The display apparatus of claim 9, wherein the first light guide plate includes a plurality of first patterns protruding from a rear surface of the first light guide plate, the first patterns having a symmetric pyramidal shape or a dot shape. 11.The display apparatus of claim 10, wherein during a second mode, second light emitted from the second light source package is refracted at a first edge of the second pattern, such that at least a portion of the refracted second light is emitted laterally with respect to an upper surface of the second light guide plate, a lateral viewing angle of the display panel being increased during the second mode. 12.The display apparatus of claim 11, wherein during a first mode, first light emitted from the first light source package is guided to a lower surface of the second light guide plate through an inclined surface or a curved surface of the first pattern, and the first light incident on the lower surface of the second light guide plate is refracted at a second edge of the second pattern, the refracted first light being emitted in an upward direction substantially perpendicular to the upper surface of the second light guide plate, and a lateral viewing angle of the display panel is limited in the first mode. 13.The display apparatus of claim 12, wherein the first mode is a private mode and the second mode is a shared mode. 14.A display apparatus comprising: a display panel configured to display an image; a first backlight unit positioned below the display panel, the first backlight unit configured to output first light to the display panel; and a second backlight unit positioned between the display panel and the first backlight unit, wherein the display panel, the first backlight unit, and the second backlight unit overlap each other, wherein during a first mode of the display apparatus, the first backlight unit is enabled and the second backlight unit is disabled, such that an image is displayed with a first side viewing angle, wherein during a second mode of the display device, the first backlight unit is activated and the second backlight unit is activated such that an image is displayed with a second side viewing angle that is greater than the first side viewing angle, wherein the second backlight unit comprises: a second light guide plate comprising a plurality of second patterns protruded or recessed from a rear surface of the second light guide plate, the second patterns having an asymmetric shape; and a second light source package configured to generate second light, wherein the second light guide plate is disposed on at least one side of the second light source package and is configured to guide the second light incident from the second light source package to the display panel, and wherein among four edges of the asymmetric shape of each of the second patterns, an angle between a first edge distal to the second light source package and the rear surface of the second light guide plate is greater than an angle between a second edge proximal to the second light source package and the rear surface of the second light guide plate. 15.The display device of claim 14, wherein the first mode is a private mode and the second mode is a shared mode. 16.The display device of claim 14, wherein the first backlight unit comprises a first light guide plate comprising a plurality of first patterns protruded or recessed from a rear surface of the first light guide plate. 17.The display device of claim 16, wherein the first patterns have a symmetric shape. 18.The display device of claim 16, wherein the first backlight unit further comprises a first light source package generating first light, wherein the first light guide plate is disposed on at least one side of the first light source package and is configured to guide the first light incident from the first light source package to the second backlight unit.

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