Backlight unit and display device

Abstract

Provided is a backlight unit comprising: a light assembly; a light guide plate which comprises, on a side surface thereof, a light incident surface facing the light assembly, and comprises a light exit surface positioned on a front surface thereof; an optical sheet which uniformly emits, in a forward direction, light emitted from the light guide plate; and a reflective sheet positioned on a rear surface of the light guide plate, wherein the center of the light incident surface in a thickness direction is spaced apart from the light assembly by a first distance, front and rear ends of the light incident surface are spaced apart from the light assembly by a second distance, and the light incident surface has a curved surface in which the first distance is greater than the second distance.

Description

Backlight unit and display device

[0001] The present invention relates to a backlight unit with improved reliability and light efficiency and a display device including the same.

[0002] As the information society develops, the demand for display devices is increasing in various forms. In response to this, display devices in recent years include Liquid Crystal Displays (LCDs), Field Emission Displays (FEDs), Plasma Display Panels (PDPs), and Electroluminescence Devices.

[0003] A liquid crystal panel of a liquid crystal display device includes a liquid crystal layer and a TFT substrate and a color filter substrate facing each other with the liquid crystal layer in between, and can display an image using light provided from a backlight unit.

[0004] As an example of an electroluminescence device, an active matrix type organic light-emitting display device is commercially available. Since organic light-emitting display devices are self-emissive, they do not require a backlight compared to liquid crystal display devices and offer advantages in response speed and viewing angle, making them a focus of attention as next-generation displays.

[0005] However, due to the issue of OLED's price competitiveness, efforts are being made to improve the image quality of liquid crystal display devices to provide display devices with quality approaching that of OLED.

[0006] Liquid crystal display devices can be classified into direct-type and edge-type backlight units, which supply light from the rear, depending on the placement of the light source. In the case of the direct-type, a light assembly is placed on the back surface to supply light from the rear of the display toward the front, while in the case of the edge-type, a light assembly is placed on the side of the display to supply light toward the front.

[0007] The edge type allows for a slim design and has the advantage of lower manufacturing costs due to the small number of light assemblies. However, since the light supplied from one side of the light guide plate is directed to the front, a difference in brightness occurs between the edges and the center, which may result in reduced brightness uniformity.

[0008] The present invention aims to provide a backlight unit capable of uniformly supplying light and improving light efficiency in an edge-type backlight unit, and a display device including the same.

[0009] A backlight unit is provided comprising: a light assembly; a light guide plate including a light receiving surface facing the light assembly on the side and a light emitting surface located on the front; an optical sheet that uniformly emits light emitted from the light guide plate forward; and a reflective sheet located on the back surface of the light guide plate, wherein the center of the light receiving surface is spaced a first distance from the light assembly in the thickness direction, the front and rear ends of the light receiving surface are spaced a second distance from the light assembly, and the light receiving surface has a curved surface in which the first distance is longer than the second distance.

[0010] The above first distance may be 1.3 times or more and 2.1 times or less of the above second distance.

[0011] The light receiving surface may include a curved surface perpendicular to the light emitted from the light assembly.

[0012] The above light guide plate further includes an uneven pattern including a plurality of protrusions formed on the back surface, and the diameter of the protrusions may increase as they are spaced further from the light assembly.

[0013] The diameter of the projection in the part adjacent to the above optical assembly may have a size of less than or equal to half the gap with the neighboring projection.

[0014] According to another aspect of the present invention, a display device is provided comprising: a display panel; and a backlight unit located on the back surface of the display panel and supplying light to the display panel, wherein the backlight unit comprises: a light assembly; a light guide plate including a light receiving surface facing the light assembly on the side and a light emitting surface located on the front; an optical sheet that uniformly emits light emitted from the light guide plate forward; and a reflective sheet located on the back surface of the light guide plate, wherein the center of the light receiving surface is spaced a first distance from the light assembly in the thickness direction, and the front and rear ends of the light receiving surface are spaced a second distance from the light assembly, and the light receiving surface has a curved surface where the first distance is longer than the second distance.

[0015] The backlight unit of the present invention can improve the reliability of the light guide plate by increasing the distance between the light source and the light-receiving surface of the light guide plate.

[0016] Light efficiency can be improved by preventing light loss on the light-receiving surface of the light guide plate due to Fresnel reflection.

[0017] The effects obtainable from the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description below.

[0018] The above light guide plate further includes an uneven pattern including a plurality of protrusions formed on the back surface, and the diameter of the protrusions may increase as they are spaced further from the light assembly.

[0019] FIG. 1 is a perspective view illustrating an example of a display device of the present invention.

[0020] FIG. 2 is an exploded perspective view illustrating an example of a display device of the present invention.

[0021] FIG. 3 is an example of a backlight unit of a display device.

[0022] FIG. 4 is a side cross-sectional view of a backlight unit of a display device of the present invention.

[0023] FIG. 5 is a side cross-sectional view of a backlight unit of a conventional display device.

[0024] FIG. 6 is a diagram showing the amount of light visible from a light guide plate according to the embodiment of FIG. 5 in color.

[0025] FIG. 7 is a side cross-sectional view of a backlight unit of a display device of the present invention.

[0026] FIG. 8 is a drawing illustrating the uneven pattern on the back surface of a light guide plate of a display device of the present invention.

[0027] FIG. 9 is a drawing showing the amount of light visible from a light guide plate according to the embodiment of FIG. 7 in color.

[0028] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Identical or similar components regardless of drawing symbols will be assigned the same reference number, and redundant descriptions thereof will be omitted. The suffixes "module" and "part" used for components in the following description are assigned or used interchangeably solely for the ease of drafting the specification and do not inherently possess distinct meanings or roles. Furthermore, in describing embodiments disclosed in this specification, if it is determined that a detailed description of related prior art could obscure the essence of the embodiments disclosed in this specification, such detailed description will be omitted. Additionally, the attached drawings are intended only to facilitate understanding of the embodiments disclosed in this specification; the technical concept disclosed in this specification is not limited by the attached drawings, and it should be understood that they include all modifications, equivalents, and substitutions that fall within the spirit and technical scope of the present invention.

[0029] Terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but said components are not limited by said terms. These terms are used solely for the purpose of distinguishing one component from another.

[0030] When it is stated that one component is "connected" or "connected" to another component, it should be understood that while it may be directly connected or connected to that other component, there may also be other components in between. On the other hand, when it is stated that one component is "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between.

[0031] A singular expression includes a plural expression unless the context clearly indicates otherwise.

[0032] In this application, terms such as “comprising” or “having” are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0033] Meanwhile, the display device (100) described in this specification is, for example, an intelligent display device (100) that adds computer support functions to a broadcast reception function, and while faithful to the broadcast reception function, it may have an interface that is more convenient to use, such as a handwriting input device, a touch screen, or a spatial remote control, by adding internet functions. In addition, it may be connected to the internet and a computer through the support of wired or wireless internet functions, and may perform functions such as email, web browsing, banking, or games. A standardized general-purpose OS may be used for these various functions.

[0034] Accordingly, the display device (100) described in the present invention can perform various user-friendly functions, for example, by allowing various applications to be freely added or deleted on a general-purpose OS kernel. More specifically, the display device (100) can be, for example, a network TV, HBB TV, smart TV, etc., and can also be applied to a smartphone depending on the case.

[0035] FIG. 1 is a front perspective view illustrating an example of a display device of the present invention. The display device (100) of the present invention may have a rectangular body including a pair of long sides and a pair of short sides. It may include a first long side (LS1), a second long side (LS2) facing the first long side (LS1), a first short side (SS1) adjacent to the first long side (LS1) and the second long side (LS2), and a second short side (SS2) facing the first short side (SS1).

[0036] Although a long side extended horizontally and a short side extended vertically are depicted on the drawing, the long and short sides may have the same length, and a form in which the long side is arranged vertically is also possible.

[0037] For the sake of convenience of explanation, the description is based on an example where the side extended in the horizontal direction (x-axis direction) is the long side and the side extended in the vertical direction (y-axis direction) is the short side, but as previously stated, it is not limited thereto.

[0038] The first direction (DR1) is a direction parallel to the long side (LS1, LS2) of the display panel (100), and the second direction (DR2) may be a direction parallel to the short side (SS1, SS2) of the display panel (100). The third direction (DR3) may be a direction perpendicular to the first direction (DR1) and / or the second direction (DR2).

[0039] The side where the display device (100) displays an image may be referred to as the front or front side. When the display device (100) displays an image, the side where the image cannot be observed may be referred to as the rear or rear side. When the display device displays an image, the side where the image cannot be observed may be referred to as the rear (rearward direction) or rear (rear side or rear surface).

[0040] When viewing the display from the front or the front, the first long side (LS1) can be referred to as the upper side or upper surface. Likewise, the second long side (LS2) can be referred to as the lower side or lower surface. Likewise, the first short side (SS1) can be referred to as the right side or right surface, and the second short side (SS2) can be referred to as the left side or left surface.

[0041] The display device may include a display unit (120) that outputs an image. A driving signal may be generated by converting an image signal, data signal, OSD signal, control signal processed by a control unit (180), or an image signal, data signal, control signal, etc. received from an interface unit. The display unit (150) may include a display panel having a plurality of pixels.

[0042] A plurality of pixels provided in the display panel may have RGB subpixels. Alternatively, a plurality of pixels provided in the display panel may have RGBW subpixels. The display unit (150) can convert an image signal, data signal, OSD signal, control signal, etc. processed by the control unit (180) to generate a driving signal for a plurality of pixels.

[0043] The display device (100) includes a display portion (120) that occupies most of the front surface area and a case that covers the back side of the display portion (120) and packages the display portion (120).

[0044] The display unit (150) can be a PDP (Plasma Display Panel), LCD (Liquid Crystal Display), OLED (Organic Light Emitting Diode), flexible display, etc., and can also be a 3D display. The 3D display unit (150) can be classified into a glasses-free type and a glasses type.

[0045] LCD displays receive light through a backlight unit because the LCD itself has difficulty emitting light. A backlight unit is a device that evenly supplies light from a light-emitting lamp to the liquid crystals located on the front. As the backlight unit becomes thinner, thin LCDs can be realized.

[0046] FIG. 2 is an exploded view of a display device (100) of the present invention. Referring to FIG. 2, the display unit (120) of the present invention is an LCD display including a display panel (510) and a backlight unit (520).

[0047] The front cover (110) can cover at least some of the front and side areas of the display panel (510). The front cover (110) can be divided into a front cover located on the front side of the display panel (510) and a side cover located on the side side of the display panel (510). The front cover and the side cover can be configured separately. Either the front cover or the side cover may be omitted.

[0048] A display panel (510) is provided on the front of a display device (100) and can display an image. The display panel (510) can display an image by having multiple pixels output RGB (red, green, or blue) for each pixel in a timed manner. The display panel (510) may be divided into an active area where an image is displayed and a de-active area where an image is not displayed. The display panel (510) may include a front substrate and a rear substrate facing each other with a liquid crystal layer in between.

[0049] The front board may include multiple pixels composed of red (R), green (G), and blue (B) subpixels. The front board may output light corresponding to the color red, green, or blue according to a control signal.

[0050] The rear substrate may include switching elements. The rear substrate may switch the pixel electrode. For example, the pixel electrode may change the molecular arrangement of the liquid crystal layer according to a control signal applied from the outside. The liquid crystal layer may include liquid crystal molecules. The liquid crystal molecules may change their arrangement in correspondence with the voltage difference generated between the pixel electrode and the common electrode. The liquid crystal layer may transmit light provided from the backlight unit (520) to the front substrate or block it.

[0051] The backlight unit (520) may be located at the rear of the display panel (510). The backlight unit (520) may include light sources. The backlight unit (520) may be coupled to the frame (130) at the front of the frame (130).

[0052] The backlight unit (520) can be driven in a full driving mode or in a partial driving mode such as local dimming, impulsive, etc. The backlight unit (520) may include an optical sheet (521, optical sheet) and an optical layer (522).

[0053] It may include a guide panel (530) for aligning the positions of the display panel (510) and the backlight unit (520). The guide panel (530) has a frame shape with four sides, and the display panel (510) and the backlight unit (520) can be seated on the front.

[0054] The optical sheet (521) can ensure that light from the light assembly (524) is evenly transmitted to the display panel (510). The optical sheet (521) may be composed of layers. For example, the optical sheet (521) may include a prism sheet, a diffusion sheet, etc.

[0055] The optical sheet (521) may be provided with a coupling portion. The coupling portion may be coupled to the front cover (110), the frame (130), and / or the back cover (120). Alternatively, the coupling portion may be fastened to a structure formed or coupled on the front cover (110), the frame (130), and / or the back cover (120).

[0056] The frame (130) can serve to support components of the display device (100). For example, components such as a backlight unit (520) can be attached to the frame (130). The frame (130) can be made of a metal material such as an aluminum alloy.

[0057] The back cover (120) may be located on the rear or back of the display device (100). The back cover (120) may be attached to the frame (130) and / or the front cover (110). For example, the back cover (120) may be an injection-molded product.

[0058] FIG. 3 is an exploded perspective view illustrating one embodiment of a backlight unit (520) of a display device (100), and FIG. 4 is a cross-sectional view illustrating one embodiment of a backlight unit (520) of a display device (100). The backlight unit (520) of this embodiment is an edge-type backlight unit (520) in which a light assembly (524) exists only in the lateral direction.

[0059] The light assembly (524) may be located on multiple sides of the light guide plate (528), but generally it may be located adjacent to one side of the first direction (D1) of the light guide plate (528). The light assembly (524) extends in a second direction (D2) perpendicular to the first direction (D1). The light assembly (524) may have a length corresponding to the length of the second direction of one side of the first direction (D1) of the light guide plate (528).

[0060] The substrate (5241) may be located on at least one side of another configuration of the optical layer (522). A light-emitting lamp (5242) or optical assemblies (524) may be mounted on the substrate (5241). An electrode pattern for connecting an adapter and a light-emitting lamp (5242) may be formed on the substrate (5241). For example, a carbon nanotube electrode pattern for connecting a light-emitting lamp (5242) and an adapter may be formed on the substrate (5241). For example, the substrate (5241) may be a Printed Circuit Board (PCB).

[0061] Light-emitting lamps (5242) may be arranged on a substrate (5241) at a predetermined interval. The light-emitting lamps (5242) may be smaller than the thickness of the light guide plate (528). Therefore, most of the light provided by the light-emitting lamps (5242) can be transmitted to the light guide plate (528).

[0062] The light-emitting lamp (5242) may be a light-emitting diode (LED) chip or a light-emitting diode package including at least one light-emitting diode chip. The light-emitting lamp (5242) may be composed of a colored LED or a white LED that emits at least one color among colors such as red, blue, green, etc.

[0063] The light source included in the light-emitting lamp (5242) may be of the COB (Chip On Board) type. The COB type may be a form in which an LED chip, which is the light source, is directly combined with the substrate (5241). Therefore, the process can be simplified. In addition, resistance can be lowered, and as a result, energy lost as heat can be reduced. That is, it means that the power efficiency of the light-emitting lamp (5242) can be increased. The COB type can provide brighter lighting. The COB type can be implemented thinner and lighter than conventional types.

[0064] The light guide plate (528) is an optical structure that guides light by spreading light incident from the light-emitting lamp (5242) widely from one side of the first direction (D1) so that light is emitted toward the front of the light guide plate (524).

[0065] A reflective sheet (525) may be located behind a light guide plate (528). The reflective sheet (525) may reflect light provided from a light-emitting lamp (5242). The reflective sheet (525) may reflect light introduced from the light guide plate (528) back to the front of the light guide plate (528). The reflective sheet (525) may include at least one of a metal and a metal oxide that is a reflective material. For example, the reflective sheet (525) may include a metal and / or a metal oxide having a high reflectivity, such as at least one of aluminum (Al), silver (Ag), gold (Au), and titanium dioxide (TiO2).

[0066] The reflective sheet (525) may be formed by depositing and / or coating a metal or metal oxide. The reflective sheet (525) may have ink containing a metal material printed on it. The reflective sheet (525) may have a deposited layer formed using a vacuum deposition method such as thermal evaporation, evaporation, or sputtering. The reflective sheet (525) may have a coating layer and / or a printed layer formed using a printing method, gravure coating method, or silk screen method.

[0067] Since the reflective sheet (525) reflects at an angle equal to the angle of incidence relative to the normal, the light reflected by the reflective sheet (525) may be emitted from the front of the light guide plate (528), but may also be reflected again and transmitted to the other side of the light guide plate (528).

[0068] In the edge type, some of the light located on one side of the light guide plate (528) is ejected forward of the light guide plate (528), and some of it moves to the other side of the light guide plate (528) and can be ejected forward from the other side of the light guide plate (528).

[0069] The back surface of the light guide plate (528) may be formed with an uneven pattern (5283, FIG. 8) that includes a plurality of protrusions that change the angle of reflection so as not to be reflected at the same angle as the angle of incidence, but to be directed forward. Among the light incident on the back surface of the light guide plate (528), the light reflected from the uneven pattern (5283) may be emitted toward the front surface of the light guide plate (528).

[0070] An optical sheet (521) located on the front of the light guide plate (528) may be further included. The diffuser plate can diffuse the light emitted from the light guide plate (528) forward.

[0071] An air gap may be located between the light guide plate (528) and the optical sheet (521). The air gap may disperse light emitted from the light-emitting lamp (5242). Meanwhile, a resin cover (5243, FIG. 7) may be formed on the light-emitting lamp (5242) and / or the reflective sheet (525). The resin cover (5243) may diffuse the light provided from the light-emitting lamp (5242).

[0072] The optical sheet (521) may be positioned in front of the light guide plate (528). The rear side of the optical sheet (521) may face the light guide plate (528), and the front side of the optical sheet (521) may face the rear side of the display panel (510).

[0073] The optical sheet (521) may include at least one sheet. The optical sheet (521) may include one or more prism sheets (PS) and / or one or more diffuser sheets (DS). Multiple sheets included in the optical sheet (521) may be in a state of being bonded and / or in close contact with each other.

[0074] For example, the optical sheet (521) may include first to third optical sheets (521a to 521c). The first optical sheet (521a) may be a diffusion sheet, and the second and third optical sheets (521b, 521c) may be prism sheets. The number and / or position of the diffusion sheets and prism sheets may be changed.

[0075] The diffusion sheet (521a) can prevent the light coming from the light guide plate (528) from being partially concentrated, thereby making the light distribution uniform. The prism sheets (521b, 521c) can concentrate the light coming from the diffusion sheet (521a) and provide light toward the display panel (510).

[0076] FIG. 5 is a side cross-sectional view of a backlight unit (520) of a conventional display device (100). In the drawing, the upper side is the front and the lower side is the rear. The light guide plate (528) of the backlight unit (520) may include a light receiving surface (5281) on one side facing a light assembly (524) and into which light emitted from the light assembly (524) is incident.

[0077] The light assembly (524) may be positioned at a predetermined distance (about 0.5 mm or less) from the light receiving surface (5281). If the light assembly (524) is positioned too far from the light receiving surface (5281), there is a concern about light loss, and if it is positioned too close, there is a problem that the light cannot spread evenly.

[0078] In addition, the central portion in the thickness direction of the light receiving surface (5281) is close to the light-emitting lamp (5242), so if the light-emitting lamp (5242) operates for a long time, the light receiving surface (5281) may be damaged by the heat of the light-emitting lamp (5242).

[0079] Additionally, depending on the position in the thickness direction of the light entry surface (5281), the distance from the light-emitting lamp (5242) may vary, and if the light is incident obliquely in a vertical direction on the light entry surface (5281), some or all of the light components may not be incident on the light guide plate (528) and may be reflected (Fresnel reflection). The light that is reflected without being incident on the light entry surface (5281) is lost and may cause a decrease in brightness and light efficiency of the backlight unit (520).

[0080] FIG. 6 is a drawing illustrating the amount of light visible from the light guide plate (528) according to the embodiment of FIG. 5. Depending on the distance from the light-emitting lamp (5242) in the longitudinal direction (horizontal direction, second direction in FIG. 6) of the light assembly (524), a large variation in the amount of light incident on the light guide plate (528) is observed.

[0081] The position (B) adjacent to the light-emitting lamp (5242) appears bright, and the difference in brightness between the position separated from it appears large. In addition, there is a problem in that the amount of light incident on the light guide plate (528) due to Fresnel reflection is insufficient, so the difference in brightness in the first direction (up and down direction in the drawing) of the light guide plate (528) appears.

[0082] FIG. 7 is a side cross-sectional view of a backlight unit (520) of a display device (100) of the present invention. The backlight unit (520) of the present invention can solve the aforementioned problem by forming a curved surface on the light receiving surface (5281).

[0083] The light entry surface (5281) may include a concave curved surface that is farthest (ⓐ) from the light-emitting lamp (5242) at the center (5281a) in the thickness direction, and protrudes in the direction of the light assembly (524) at the front and rear ends (5281b) to be closer (ⓑ) to the light-emitting lamp (5242).

[0084] The light receiving surface (5281) may include a curved surface where the angle of incidence of light incident from the light-emitting lamp (5242) is perpendicular. When light is incident perpendicularly on the light receiving surface (5281), Fresnel reflection does not occur, thereby reducing light loss.

[0085] By analyzing the direction of light emitted from the light-emitting lamp (5242), the light-receiving surface (5281) can be implemented so that the angle of incidence is perpendicular. Alternatively, if a dome-shaped light source lens (5243) covering the light-emitting lamp (5242) is included, the curved surface of the light-receiving surface (5281) can be formed so that the distance from the surface of the light source lens (5243) is constant.

[0086] The curved surface of the light receiving surface (5281) may be configured in the form of a continuous groove extending along one side of the light guide plate (528), or in the form of a hemisphere centered on the light-emitting lamp (5242) of the light assembly (524).

[0087] In the latter case, there is an advantage in that light loss can be reduced, but the amount of light incident on the light guide plate (528) between the hemispherical light receiving surfaces (5281) is reduced, so the light may become uneven in the direction of the light receiving surfaces (5281).

[0088] In the former case, some of the light from the light-emitting lamp (5242) may be reflected, but since the light-receiving surface (5281) has a continuous surface, the light incident on the light guide plate (528) can have continuity. In addition, since the light guide plate (528) having a continuous curved light-receiving surface (5281) is easy to manufacture, the following description will be based on a groove-shaped light-receiving surface (5281) that is continuously connected along one side of the light guide plate (528).

[0089] The first distance (a) from the light-emitting lamp (5242) to the center of the light-receiving surface (5281) is longer than the second distance (b) to the front or rear end of the light-receiving surface (5281), and the first distance may have a value of 1.3 times or more and 2.1 times or less than the second distance. If the distance ratio is too small, Fresnel reflection occurs and there is no improvement in light efficiency, and if it is too large, a problem may occur where the light spreading effect becomes too large.

[0090] FIG. 8 is a drawing illustrating an uneven pattern (5283) on the back surface of a light guide plate (528) of a display device (100) of the present invention.

[0091] Since light efficiency is improved through the curved surface of the light receiving surface (5281), the size of the uneven pattern (5283) at a position adjacent to the light receiving surface (5281) (within 10% of the length of the light guide plate (528)) can be reduced in order to reduce the ratio of light emitted forward at a position adjacent to the light receiving surface (5281).

[0092] The protrusions (5283a, 5283b) of the uneven pattern (5283) may be arranged in an irregular pattern, or as shown in FIG. 8, a plurality of protrusions (5283a, 5283b) may be arranged in a grid.

[0093] The uneven pattern (5283) of the present invention is composed of a plurality of protrusions (5283a, 5283b) arranged in a grid pattern, and the area occupied by the plurality of protrusions (density of the plurality of protrusions) can be varied by adjusting the size of the protrusions (5283a, 5283b).

[0094] The diameter (ⓓ) of the first protrusion (5283a) located within 10% of the first direction length (upward and downward length on the drawing) of the light guide plate (528) on one side where the light receiving surface (5281) of the light guide plate (528) is located may have a size of 0.5 times or less of the gap (pitch ⓒ) with the adjacent protrusion (5283a).

[0095] If the diameter of the first projection (5283a) is too small, the amount of protrusion of the first projection (5283a) is reduced, and the amount of light emitted forward is reduced. Therefore, the diameter of the first projection (5283a) can be configured to have a value of at least 0.15 times the spacing (ⓒ) between the projections (5283a).

[0096] The size (ⓓ) of the first projection (5283a) adjacent to one side of the light guide plate (528) may be less than or equal to half the size (ⓔ) of the second projection (5283b) adjacent to the other side.

[0097] FIG. 9 is a diagram showing the amount of light visible from the light guide plate (528) according to the embodiment of FIG. 7 in color. It can be confirmed that the brightness of one side of the light guide plate (528), which is highly bright due to the light-emitting lamp (5242) of the conventional backlight unit (520), is uniformly displayed, and the brightness of the first direction (D1) of the light guide plate (528) is also distributed uniformly overall. As seen above, the backlight unit (520) of the present invention can improve the reliability of the light guide plate (528) by increasing the distance between the light source and the light-receiving surface (5281) of the light guide plate (528).

[0098] Light loss from the light-receiving surface (5281) of the light guide plate (528) due to Fresnel reflection can be prevented to improve light efficiency.

[0099] The foregoing detailed description should not be interpreted restrictively in all respects and should be considered exemplary. The scope of the invention shall be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the invention are included within the scope of the invention.

[0100] Regarding various embodiments for implementing the present invention, descriptions that are redundant with those described above in the previous section on the best mode for carrying out the invention are omitted.

[0101] Since the present invention is applicable to backlight units and display devices in various fields, its industrial applicability is recognized.

Claims

1. Optical assembly; A light guide plate including a light receiving surface facing the light assembly on the side and a light emitting surface located on the front; An optical sheet that uniformly directs light ejected from the light guide plate forward; and It includes a reflective sheet located on the back surface of the light guide plate, and The center of the above-mentioned light receiving surface is spaced a first distance from the light assembly in the thickness direction, and The front and rear ends of the light receiving surface are spaced apart by a second distance from the light assembly, and A backlight unit characterized in that the light receiving surface has a curved surface where the first distance is longer than the second distance.

2. In Paragraph 1, A backlight unit characterized in that the first distance is 1.3 times or more and 2.1 times or less of the second distance.

3. In Paragraph 1, A backlight unit characterized in that the light receiving surface includes a curved surface perpendicular to the light emitted from the light assembly.

4. In Paragraph 1, It further includes an uneven pattern including a plurality of protrusions formed on the back surface of the light guide plate, and A backlight unit characterized in that the diameter of the above-mentioned protrusion becomes larger as it is spaced further from the above-mentioned light assembly.

5. In Paragraph 4, A backlight unit characterized in that the diameter of the projection in a portion adjacent to the light assembly has a size of 1 / 2 or less of the gap with an adjacent projection.

6. Display panel; and It includes a backlight unit located on the back surface of the display panel and supplying light to the display panel, The above backlight unit is, Optical assembly; A light guide plate including a light receiving surface facing the light assembly on the side and a light emitting surface located on the front; An optical sheet that uniformly directs light ejected from the light guide plate forward; It includes a reflective sheet located on the back surface of the light guide plate, and The center of the above-mentioned light receiving surface is spaced a first distance from the light assembly in the thickness direction, and The front and rear ends of the light receiving surface are spaced apart by a second distance from the light assembly. A display device characterized in that the light-receiving surface has a curved surface where the first distance is longer than the second distance.

7. In Paragraph 6, It further includes an uneven pattern including a plurality of protrusions formed on the back surface of the light guide plate, and A display device characterized in that the diameter of the above-mentioned protrusion becomes larger as it is spaced further from the above-mentioned optical assembly.

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