Light diffusion lens, and backlight unit and display device including same

Abstract

The present invention relates to a light diffusion lens, and a backlight unit and a display device which include the light diffusion lens. The light diffusion lens covers an LED and comprises: a circular incident recess formed in the lower surface of the light diffusion lens and accommodating the LED; an incident surface protruding convexly upward from the incident recess; an exit surface positioned above the incident surface and protruding in a dome shape from the upper surface of the light diffusion lens; a flange protruding laterally from the lower end of the exit surface; and a guide protrusion protruding upward from the upper surface of the flange.

Description

Light diffusion lens, backlight unit including same, and display device

[0001] The present embodiments relate to a light diffusion lens, a backlight unit including the same, and a display device, and more specifically, to a light diffusion lens for easy fastening of a reflective sheet, and a backlight unit including the same and a display device.

[0002] In general, among displays, LCD (Liquid Crystal Display) is used in various devices ranging from televisions, laptop computers, desktop computer monitors, and mobile phones.

[0003] Since these LCDs do not emit light on their own, a light-emitting device that can illuminate the liquid crystal panel is required to display image information.

[0004] The light-emitting device of the LCD is connected to the back of the liquid crystal panel, so it is called a backlight unit. This backlight unit can be said to be a device that forms a uniform surface light source and provides a light source to the liquid crystal panel.

[0005] These backlight units are divided into edge-type and direct-type depending on where the light source is installed. Among these, the direct-type was developed primarily as the size of liquid crystal displays began to increase to 20 inches or larger. It directly illuminates the front of the liquid crystal panel by arranging multiple light sources in a row on the back of the diffusion plate.

[0006] Previously, liquid crystal displays mainly used cold cathode ray tube lamps, but recently, liquid crystal displays that use light generated from light-emitting diodes have been widely used.

[0007] Light-emitting diodes have the advantages of low power consumption and high brightness, but have the disadvantage of very poor brightness uniformity.

[0008] In order to improve the uniformity of brightness of light generated from a light emitting diode, a light diffusion lens that diffuses the light generated from the light emitting diode is generally placed on the light emitting diode.

[0009] Therefore, a method of attaching a reflective sheet to a light diffusing element by fitting the reflective sheet is used, but there is a problem that scratches occur on the light diffusing element due to the reflective sheet when fitting the reflective sheet.

[0010] The present invention is intended to solve the above-described problems, and the technical task of embodiments of the present invention is to provide a light diffusion lens including a guide protrusion protruding at a certain height on the flange side.

[0011] In addition, embodiments of the present invention have as their technical task a light diffusion lens having an inclined surface having a lower surface having a certain slope.

[0012] The problems to be solved by the present invention are not limited to those described above, and other problems not mentioned will be clearly understood by those skilled in the art to which the present invention pertains from the description below.

[0013] According to embodiments for solving the technical problem described above, a light diffusion lens may include a light diffusion lens covering an LED, a circular entrance formed on a lower surface of the light diffusion lens and accommodating the LED, an entrance surface convexly retracted upward from the entrance surface, an exit surface positioned on an upper side of the entrance surface and protruding in a dome shape from an upper surface of the light diffusion lens, a flange protruding laterally from a lower end of the exit surface, and a guide protrusion protruding upward from an upper surface of the flange.

[0014] According to embodiments, the guide protrusion may have a cross-sectional area that decreases from the lower end to the upper end.

[0015] According to embodiments, the height of the guide protrusion may be smaller than the height of the exit surface.

[0016] According to embodiments, at least a portion of the lower edge of the guide protrusion may contact an edge of the flange.

[0017] According to embodiments, the device further includes a total reflection groove positioned around the periphery of the inlet and recessed upward, wherein the total reflection groove may include an inclined surface extending upward from the inlet.

[0018] According to embodiments, the angle formed by the upper end of the guide protrusion may be 70 degrees or greater.

[0019] According to embodiments, the width of both ends of the guide protrusion may become narrower towards both ends.

[0020] According to embodiments, the guide protrusions may be arranged in a plurality of rows.

[0021] According to embodiments, the lower surface of the guide protrusion may have an oval shape or a circular shape.

[0022] According to embodiments, the guide protrusion may include a first guide protrusion located on one side of the exit portion and a second guide protrusion located on the other side of the exit portion and having point symmetry with the first guide protrusion.

[0023] According to embodiments, both ends of the first guide protrusion and the second guide protrusion can be formed within 120 degrees from the center of the exit portion.

[0024] According to embodiments for solving the technical problem described above, a backlight unit includes an LED array bar including a plurality of LEDs spaced apart from each other in a first direction, a light diffusion lens formed on the LED array bar to cover each of the LEDs, and a reflective sheet mounted on the LED array bar and having a plurality of holes formed corresponding to the LEDs, wherein the light diffusion lens includes a circular entrance formed on a lower surface of the light diffusion lens and accommodating the LED, an entrance surface convexly retracted upward from the entrance surface, an exit surface positioned above the entrance surface and protruding in a dome shape on an upper surface of the light diffusion lens, a flange protruding laterally from a lower end of the exit surface, and a guide protrusion protruding upward from an upper surface of the flange, wherein at least a portion of the guide protrusion can overlap with the reflective sheet.

[0025] According to embodiments, the hole has a pair of straight boundaries formed to face each other on both sides and a pair of curved boundaries formed to connect both ends of the straight boundaries and to face each other on both sides, and the guide protrusion can be formed at a position overlapping the straight boundaries.

[0026] According to embodiments, the upper end of the guide protrusion may be formed at a position where it meets the straight boundary.

[0027] According to embodiments, the guide protrusion has a cross-sectional area that decreases from the lower end to the upper end, the height of the guide protrusion is smaller than the height of the exit surface, and at least a portion of the lower edge of the guide protrusion can contact the edge of the flange.

[0028] According to embodiments, a joining hole may be formed on the LED array bar to which the light diffusion lens is joined.

[0029] According to embodiments, the LED array bars are arranged in plurality in the second direction perpendicular to the first direction, and the reflective sheet can cover the plurality of LED array bars simultaneously.

[0030] According to embodiments for solving the technical problem described above, a display device includes a display panel, a frame positioned at the rear of the display panel, an LED array bar positioned between the display panel and the frame and including a plurality of LEDs that provide light to the display panel, a light diffusion lens formed on the LED array bar to cover each of the LEDs, and a reflective sheet mounted on the LED array bar and having a plurality of holes formed corresponding to the LEDs, wherein the plurality of LEDs are arranged to be spaced apart from each other in a first direction, the light diffusion lens includes a circular entrance hole formed on a lower surface of the light diffusion lens and accommodating the LEDs, an entrance surface convexly retracted upward from the entrance hole, an exit surface positioned above the entrance surface and protruding in a dome shape on an upper surface of the light diffusion lens, a flange protruding laterally from a lower end of the exit surface, and a guide protrusion protruding upward from an upper surface of the flange, wherein at least a portion of the guide protrusion can overlap with the reflective sheet.

[0031] According to embodiments, by providing a light diffusion lens including a guide protrusion protruding at a certain height on the flange side, there is an effect that scratches do not occur on the emission surface and the flange even when the reflective sheet is fitted.

[0032] According to embodiments, by providing a light diffusing lens having a sloped surface with a certain slope on the lower surface, there is an effect that light emitted from a light source does not interfere with a guide protrusion.

[0033] The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present invention belongs from the description below.

[0034] FIG. 1 is a perspective view illustrating an example of a display device according to embodiments.

[0035] FIG. 2 is an exploded view illustrating a display unit of a display device according to embodiments.

[0036] Figures 3 and 4 are drawings showing a state in which a conventional reflective sheet is bonded to a substrate.

[0037] Fig. 5 is a drawing showing a state formed on an LED array bar of a light diffusion lens according to embodiments.

[0038] Fig. 6 is a drawing showing a light diffusion lens according to embodiments.

[0039] Fig. 7 is a drawing showing an example of a cross-section of a guide protrusion of a light diffusion lens according to embodiments.

[0040] FIG. 8 is a drawing showing an example of the upper position of the guide protrusion of the light diffusion lens according to embodiments.

[0041] FIG. 9 is a drawing showing an example of the lower surface of a guide protrusion of a light diffusion lens according to embodiments.

[0042] Fig. 10 is a drawing showing an example of the positions of both ends of the guide protrusions of the light diffusion lens according to embodiments.

[0043] Fig. 11 is a drawing showing a total reflection groove of a light diffusion lens according to embodiments.

[0044] Fig. 12 is a drawing showing a state in which a light diffusion lens and a reflective sheet according to embodiments are viewed from above.

[0045] Fig. 13 is a drawing showing a state in which a reflective sheet of a backlight unit according to embodiments is combined.

[0046] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Regardless of the drawing numbers, identical or similar components are given the same reference numbers and redundant descriptions thereof will be omitted.

[0047] The suffixes "module" and "part" used in the following description are assigned or used interchangeably solely for the convenience of writing the specification, and do not in themselves have distinct meanings or roles. Furthermore, when describing the embodiments disclosed herein, if a detailed description of a related known technology is deemed to obscure the gist of the embodiments disclosed herein, the detailed description will be omitted.

[0048] In addition, the attached drawings are only intended to facilitate easy understanding of the embodiments disclosed in this specification, and the technical ideas disclosed in this specification are not limited by the attached drawings, and should be understood to include all modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention.

[0049] Terms that include ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by these terms. These terms are used solely to distinguish one component from another.

[0050] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0051] Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0052] In this application, terms such as “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but should be understood not to exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0053]

[0054] FIG. 1 is a perspective view illustrating an example of a display device according to embodiments.

[0055] As illustrated in FIG. 1, the display device (100) may have a rectangular shape including a first long side (First Long Side, LS1), a second long side (Second Long Side, LS2) opposite the first long side (LS1), a first short side (First Short Side, SS1) adjacent to the first long side (LS1) and the second long side (LS2), and a second short side (Second Short Side, SS2) opposite the first short side (SS1).

[0056] Here, the first short side area (SS1) may be referred to as the first side area, the second short side area (SS2) may be referred to as the second side area facing the first side area, the first long side area (LS1) may be referred to as the third side area adjacent to the first side area and the second side area and located between the first side area and the second side area, and the second long side area (LS2) may be referred to as the fourth side area adjacent to the first side area and the second side area and located between the first side area and the second side area and facing the third side area.

[0057] In addition, for convenience of explanation, the lengths of the first and second long sides (LS1, LS2) are illustrated and described as being longer than the lengths of the first and second short sides (SS1, SS2), but it may also be possible for the lengths of the first and second long sides (LS1, LS2) to be approximately the same as the lengths of the first and second short sides (SS1, SS2).

[0058] In addition, the first direction (DR1) below may be a direction parallel to the long side (LS1, LS2) of the display device (100), and the second direction (DR2) may be a direction parallel to the short side (SS1, SS2) of the display device (100). The third direction (DR3) may be a direction perpendicular to the first direction (DR1) and / or the second direction (DR2).

[0059] From another perspective, the side of the display device (100) that displays an image may be referred to as the front or front side. When the display device (100) displays an image, the side from which the image cannot be observed may be referred to as the rear or back side. When viewing the display device (100) from the front or front, the first long side (LS1) may be referred to as the upper side or upper surface. Similarly, the second long side (LS2) may be referred to as the lower side or lower surface. Similarly, the first short side (SS1) may be referred to as the right side or right surface, and the second short side (SS2) may be referred to as the left side or left surface.

[0060] In addition, the first long side (LS1), the second long side (LS2), the first short side (SS1), and the second short side (SS2) may be referred to as edges of the display device (100). In addition, the point where the first long side (LS1), the second long side (LS2), the first short side (SS1), and the second short side (SS2) meet each other may be referred to as a corner. For example, the point where the first long side (LS1) and the first short side (SS1) meet may be referred to as a first corner (C1), the point where the first long side (LS1) and the second short side (SS2) meet may be referred to as a second corner (C2), the point where the second short side (SS2) and the second long side (LS 2) meet may be referred to as a third corner (C3), and the point where the second long side (LS2) and the first short side (SS1) meet may be referred to as a fourth corner (C4).

[0061] Here, the direction from the first short side (SS1) to the second short side (SS2) or the direction from the second short side (SS2) to the first short side (SS1) may be referred to as the left-right direction (LR). The direction from the first long side (LS1) to the second long side (LS2) or the direction from the second long side (LS2) to the first long side (LS1) may be referred to as the up-down direction (UD).

[0062] The display device includes a display panel that occupies most of the front surface area and a case that covers the rear side of the display panel and packages the display panel.

[0063] Recently, display devices (100) can utilize a display unit (110) that can be bent, such as LEDs (Light Emitting Diodes) or OLEDs (Organic Light Emitting Diodes), to implement a curved screen rather than a flat screen.

[0064] Previously, LCDs were primarily used because they were unable to emit light on their own, so they relied on backlight units for light. Backlight units are devices that evenly distribute light from a light source to the liquid crystal display (LCD) located at the front. While thinner backlight units have enabled thinner LCDs, it's difficult to create them using flexible materials. Furthermore, bending the backlight unit hinders the supply of even light to the LCD, causing screen brightness to fluctuate.

[0065] On the other hand, in the case of LEDs or OLEDs, since each element forming a pixel emits light on its own, it is possible to implement a curved display without using a backlight unit. In addition, since each element emits light on its own, even if the positional relationship with neighboring elements changes, its own brightness is not affected, so a curved display unit (110) can be implemented using LEDs or OLEDs.

[0066] OLED (Organic Light-Emitting Diodes) panels made their debut in the mid-2010s and are rapidly replacing LCDs in the small- and medium-sized display market. OLEDs utilize the self-luminous phenomenon, where fluorescent organic compounds emit light when current flows through them. Their image quality response speed is faster than that of LCDs, resulting in virtually no afterimages when displaying video.

[0067] OLED uses three types of fluorescent organic compounds with self-luminous functions: red, green, and blue. It is a luminescent display product that utilizes the phenomenon in which electrons injected from the cathode and anode and positively charged particles combine within the organic material to emit light on their own, so there is no need for a backlight (backlight device) that reduces color.

[0068] The LED (Light Emitting Diode) panel is a technology that uses one LED element as one pixel, and since the size of the LED element can be reduced compared to the past, a flexible display unit (110) can be implemented. Devices previously called LED TVs used LEDs as a light source for a backlight unit that supplied light to an LCD, and the LEDs themselves did not form a screen.

[0069] The display unit includes a display panel, a coupling magnet located on the back of the display panel, a first power supply unit, and a first signal module. The display panel may include a plurality of pixels (R, G, B). The plurality of pixels (R, G, B) may be formed in each area where a plurality of data lines and a plurality of gate lines intersect. The plurality of pixels (R, G, B) may be arranged or arranged in a matrix form.

[0070] For example, a plurality of pixels (R, G, B) may include a red (Red, hereinafter referred to as 'R') sub-pixel, a green (Green, 'G') sub-pixel, and a blue (Blue, 'B') sub-pixel. The plurality of pixels (R, G, B) may further include a white (White, hereinafter referred to as 'W') sub-pixel.

[0071] The side of the display unit (110) that displays an image can be referred to as the front or front. When the display unit (110) displays an image, the side from which the image cannot be observed can be referred to as the rear or back.

[0072] FIG. 2 is an exploded view illustrating a display unit of a display device according to embodiments.

[0073] The display unit (110) illustrated in FIG. 2 corresponds to the display unit (110) illustrated in FIG. 1.

[0074] The display unit (110) may include a display module (20) and a backlight unit (30) that provides light to the display module (20) from the rear of the display module (20). The display unit (110) may further include a front cover (10), a frame (40), a circuit unit (50), a back cover (60), etc.

[0075] The display unit (110) may have an approximately rectangular shape having a constant width in the horizontal direction (horizontal direction, x-axis direction of FIG. 2) and a constant length in the vertical direction (vertical direction, y-axis direction of FIG. 2). In FIG. 2, the display unit (110) is exemplified as having a long side in the horizontal direction and a short side in the vertical direction, but the width in the horizontal direction and the length in the vertical direction of the display unit (110) may be substantially the same, or the display unit (110) may have a short side in the horizontal direction and a long side in the vertical direction. In addition, the thickness direction perpendicular to the screen of the display unit (110) may be referred to as the front-back direction (z-axis direction of FIG. 2). At this time, the direction from the back cover (60) of the display unit (110) toward the display module (20), that is, the direction toward the surface where the image is displayed, can be referred to as the front (negative z-axis direction in the drawing), and the direction from the display module (20) of the display unit (110) toward the back cover (60), that is, the direction toward the surface where the image is not displayed, can be referred to as the rear (positive z-axis direction in the drawing).

[0076] The backlight unit (30) may be positioned on the rear side of the display module (20) to provide light to the display module (20). The backlight unit (30) according to embodiments may have a direct structure having a plurality of light sources (36) positioned on the rear side of the display module (20). The backlight unit (30) may be driven by a full driving method or a partial driving method such as a screen split driving (local dimming) or an impulsive driving method. The direct structure is suitable for the partial driving method as well as the full driving method, and may maximize the contrast ratio. More specifically, the backlight unit (30) may include a light source member (32) having a plurality of light sources (36) and the like to emit light, and an optical member (300) positioned on the front of the light source member (32) to control the light. The light source member (32) may include a substrate (34), a plurality of light assemblies (36), and a wiring unit (38). The light assembly (36) may be composed of a plurality of light sources and a lens surrounding the light sources.

[0077] For example, the substrate (34) may have a shape of a line or strap that extends in a first direction while having a constant width. On each substrate (34), a plurality of light assemblies (36) may be arranged at a predetermined interval from each other in the first direction, which is the extending direction of the substrate (34), to form a single string. The diameter of the light assembly (36) may be larger than the width of the substrate (34) in a second direction intersecting (for example, orthogonal to) the first direction, but the present invention is not limited thereto. In this way, a plurality of substrates (34) (i.e., strings) equipped with a plurality of light assemblies (36) may be positioned in plurality with a constant interval from each other in the second direction. According to this structure, a plurality of light sources (36) can be positioned regularly and evenly over the entire area of ​​the backlight unit (30) or the display module (20).

[0078] The substrate (34) can support a plurality of optical assemblies (36) and electrically connect the optical assemblies (36) to the light source control unit (54). To this end, the substrate (34) can have a base member made of an insulating material and an electrode pattern formed on the base member. Here, the base member can be made of polyethylene terephthalate (PET), glass, polycarbonate (PC), silicon, or the like, and the electrode pattern can be made of a conductive material such as a metal or carbon nanotube. For example, the substrate (34) can be a printed circuit board (PCB).

[0079] A plurality of strings can be electrically connected to the circuit unit (50) by the wiring unit (38). That is, the wiring unit (38) can electrically connect the electrode patterns of the plurality of strings and the circuit unit (50). Here, the wiring unit (38) is connected to the plurality of strings in the second direction, and can be formed to individually drive the plurality of strings. In addition, the wiring unit (38) can be formed to individually drive the plurality of light assemblies (36) provided in each string, or can be formed to collectively drive the plurality of light assemblies (36) provided in each string. In Fig. 2, the wiring unit (38) is exemplified as being located on one side (one side in the first direction) of the plurality of strings, but the present invention is not limited to the position of the wiring unit (38).

[0080] Among the light assemblies (36), the light source may be composed of a light-emitting unit that emits light, or may be composed of a light-emitting package including the light-emitting unit. For example, the light-emitting unit may be a light-emitting diode (LED) chip, and the light source may be composed of a light-emitting diode chip or a light-emitting diode package. Here, the light-emitting diode chip may be composed of a colored light-emitting diode chip that emits one color among red, green, blue, etc., or may be composed of a white light-emitting diode chip that emits white. When the light-emitting unit includes a colored light-emitting diode chip, it may include a colored light-emitting diode chip that emits one color, or it may include a plurality of colored light-emitting diode chips that emit different colors.

[0081] The optical member (300) positioned on the front side of the light source member (32) (more specifically, the front side of the substrate (34) and the light assembly (36)) can play a role in inducing reflection, diffusion, etc. of light emitted from the light source member (32) so that light is efficiently and evenly provided to the display module (20).

[0082] In Fig. 2, as an example, an optical member (31) is provided with a reflective sheet (33), a diffuser plate (35), and an optical sheet (37).

[0083] The reflective sheet (33) positioned on the front surface of the substrate (34) may have a sheet shape provided with holes (33a) through which the optical assemblies (360) pass. For example, the reflective sheet (33) may have a plurality of holes (33a) corresponding one-to-one to a plurality of optical assemblies (36), and may have a shape in which areas including the plurality of holes (33a) are connected to each other as an integral structure.

[0084] The reflective sheet (33) can serve to increase the amount of light reaching the display module (20) by reflecting light emitted from the optical assembly (36), light reflected from the diffuser plate (35), etc. forward.

[0085] Here, the reflective sheet (302) may include a metal having high reflectivity, such as aluminum, silver, or gold, or a metal oxide having high reflectivity, such as titanium oxide (TiO2). The optical sheet (306) is positioned on the front side of the diffuser plate (304) and is in close contact with the rear side of the display module (20) so that light emitted from the light source (36) can be evenly transmitted to the display module (20).

[0086] The optical sheet (37) may be composed of one layer or multiple layers. For example, the optical sheet (37) may include at least one diffusion sheet and / or at least one prism sheet. The diffusion sheet prevents light from being partially concentrated to ensure uniform brightness over the entire area, and the prism sheet is positioned in front of the diffusion sheet to collect light emitted from the diffusion sheet so that the light is incident perpendicularly to the display module (20).

[0087] This backlight unit (30) can be coupled to the frame (40) so that a plurality of light sources (36) are positioned toward the display module (20) on the front side of the frame (40) to provide light to the display module (20). The frame (40) can serve to support a member included in the display unit (110). For example, in the present embodiment, the backlight unit (30) can be coupled to and supported by the frame (40). The frame (40) can be made of a metal material (e.g., aluminum alloy) so as to stably support the backlight unit (30), etc.

[0088] The back cover (60) prevents the rear of the display module (20), the backlight unit (30), the circuit unit (50), etc. from being exposed to the outside, thereby stably protecting the display module (20), the backlight unit (30), the circuit unit (50), etc., and improving the appearance of the display unit (110).

[0089] The back cover (60) may have various structures, materials, sizes, thicknesses, etc. that can cover and protect the display module (20), etc. For example, the back cover (60) may form an integral structure at the rear of the display module (20). As another example, the back cover (60) may separately include a cover that covers a portion other than the circuit unit (50) and a cover that covers the circuit unit (50). In addition, the back cover (60) may have various structures. The back cover (60) may include various materials such as metal, polymer material (e.g., resin), and reinforced fiber. For example, the back cover (60) may be composed of a resin that is lightweight, easy to mold, and inexpensive. However, the present invention is not limited thereto, and the shape, material, etc. of the back cover (60) may be variously modified.

[0090] FIG. 3 and FIG. 4 are drawings showing a state in which a conventional reflective sheet is bonded to a substrate. More specifically, FIG. 3 is a drawing showing a state in which a conventional reflective sheet is bonded to a substrate by fitting it to a lens, and FIG. 4 is a drawing showing a state in which a conventional reflective sheet is attached to a substrate using double-sided tape.

[0091] Referring to FIG. 3, in the conventional case, when the flange (220) of the lens (200) is used to fit the reflective sheet to the substrate (230), scratches may occur on the emission surface (210) and the flange (210) of the lens (200) due to the frictional force of the reflective sheet (230). That is, in order to fit the reflective sheet to the lens (200), the reflective sheet has no choice but to be formed to partially overlap with the end portion of the lens (200), and there is a problem that the reflective sheet moves due to such overlapping reflective sheets, thereby causing scratches on the lens (200).

[0092] In addition, the reflective sheet overlapped by the flange (220) that is formed to protrude outward from the emission surface (210) may not be fixed to the substrate (230) but may remain on the upper surface of the flange (220). That is, when the reflective sheet is bonded to the substrate (230), there is a problem that an interference effect occurs due to the flange (220).

[0093] Referring to Fig. 4, when attaching the reflective sheet to the substrate (230) rather than fitting the reflective sheet to the lens (200), double-sided tape can be used. In this case, there is a problem in that a double-sided tape of a length corresponding to the length of the reflective sheet must be attached, which requires a lot of cost.

[0094] Therefore, a light diffusion lens according to embodiments capable of solving the above problem will be described below.

[0095] Fig. 5 is a drawing showing a state in which a light diffusion lens is formed on an LED array bar according to embodiments. Fig. 6 is a drawing showing a light diffusion lens according to embodiments. More specifically, Fig. 6 (a) is a drawing showing a state in which a light diffusion lens according to embodiments is viewed from above, and Fig. 6 (b) is a drawing showing a cross-section of a light diffusion lens according to embodiments when viewed from the side.

[0096] The LED array bar (300) illustrated in FIG. 5 may correspond to the substrate (34) illustrated in FIG. 2. The light diffusion lens (400) illustrated in FIG. 6 may correspond to the light diffusion lens (400) illustrated in FIG. 5.

[0097] As illustrated in FIGS. 5 and 6, the light diffusion lens (400) according to the embodiments may include an entrance port (410), an entrance surface (412), a total reflection groove (414), an exit surface (420), a flange (430), and a guide protrusion (440). More specifically, the entrance port (410), the entrance surface (412), and the total reflection groove (414) may be formed on a lower surface of the light diffusion lens (400), the exit surface (420) and the guide protrusion (440) may be formed on an upper surface of the light diffusion lens (400), and the flange (430) may be formed on a side surface of the light diffusion lens (400).

[0098] Referring to FIG. 5, a light diffusion lens (400) may be positioned on the LED array bar (300) to cover the LEDs (310) formed on the LED array bar (300). A protrusion (418) protruding to a certain height may be formed on the lower surface of the light diffusion lens (400), and the light diffusion lens (400) may be coupled to the LED array bar (300) by the protrusion (418) being coupled to the coupling hole (305) formed in the LED array bar (300).

[0099] The entrance port (410) can accommodate an LED (310). That is, the entrance port (410) can meet the LED array bar (300) in which the LED (310) is formed. The entrance port (410) can have any shape that can accommodate the LED (310).

[0100] The incident surface (412) is formed by being convexly introduced upward from the incident port (410), so that light emitted from the LED (310) can enter the interior of the light diffusion lens (400) through the incident surface (412). In addition, the incident light can be diffused through the emission surface (420) located above the incident surface (412).

[0101] A total reflection groove (414) may be formed on the lower surface of the light diffusion lens (400) and is positioned around the entrance port (410) and is concavely recessed upward. A detailed description of the total reflection groove (414) will be described in FIG. 11.

[0102] As described above, the emission surface (420) can emit light incident through the incident surface (412), and can be formed in a dome shape to diffuse the light emitted from the LED (310).

[0103] The flange (430) may be formed to protrude laterally from the lower end of the exit surface (420). That is, as shown in (a) of FIG. 6, the outer circumference of the flange (430) may be positioned further outward than the outer circumference of the exit surface (420).

[0104] The guide protrusion (440) may be formed to protrude upward from the upper surface of the flange (420). That is, as illustrated in FIGS. 5 and 6, the guide protrusion (440) may be positioned between the outer surface of the flange (430) and the outer surface of the exit surface (420). At this time, the height of the guide protrusion (440) may be formed to be smaller than the height of the exit surface (420). More specifically, the height of the guide protrusion (440) may be formed to be larger than half the height of the exit surface (420) and may preferably be formed to be smaller than 2 / 3 of the height of the exit surface (420).

[0105] The guide protrusion (440) may be formed so that its cross-sectional area gradually decreases from the bottom to the top. That is, the guide protrusion (440) may be formed with an upper end (445). Referring to (b) of Fig. 6, the cross-section of the guide protrusion (440) may be formed with a first surface (441) formed on the flange (430) side and a second surface (443) formed on the exit surface (420) side based on the upper end (445). At this time, the first surface (441) and the second surface (443) may be formed to be inclined.

[0106] In particular, since the first surface (441) is formed to be inclined, even when a reflective sheet (500, see FIG. 13) is fastened, a situation of interference by the guide protrusion (440) may not occur.

[0107] Referring to FIG. 6, at least a portion of the lower edge of the guide protrusion (440) may be in contact with the edge of the flange (430). More specifically, the lower end of the first surface (441) of the cross-section of the guide protrusion (440) may be in contact with the edge of the flange (220). In addition, the lower edge of the guide protrusion (440) may be in contact with the lower end of the exit surface (420), or may be positioned a certain distance apart from the lower end of the exit surface (420).

[0108] That is, when the lower edge of the guide protrusion (440) formed on the flange (430) side is in contact with the edge (perimeter) of the flange (430), a wear phenomenon may not occur on the flange (430) by the reflective sheet (500, see FIG. 13) when the reflective sheet (500) is fastened.

[0109] Fig. 7 is a drawing showing an example of a cross-section of a guide protrusion of a light diffusion lens according to embodiments. Fig. 8 is a drawing showing an example of the upper position of a guide protrusion of a light diffusion lens according to embodiments.

[0110] The light diffusion lens (400) illustrated in FIG. 7 may correspond to the light diffusion lens (400) illustrated in FIGS. 5 and 6. The guide protrusion (440) illustrated in FIG. 7 may correspond to the guide protrusion (400) illustrated in FIGS. 5 and 6. The exit surface (420) illustrated in FIG. 8 may correspond to the exit surface (420) illustrated in FIGS. 5 and 6. The flange (430) illustrated in FIG. 8 may correspond to the flange (430) illustrated in FIGS. 5 and 6. The guide protrusion (440) illustrated in FIG. 8 may correspond to the guide protrusion (440) illustrated in FIGS. 5 and 6.

[0111] As illustrated in FIG. 7, the guide protrusion (440) may have a cross-section of various shapes. For example, as illustrated in (a) of FIG. 7, the guide protrusion (440) may have a cross-section of a triangular shape, and as illustrated in (b) of FIG. 7, the guide protrusion (440) may have a cross-section of a triangular shape with a curved upper portion. Alternatively, for example, as illustrated in (c) of FIG. 7, the guide protrusion (440) may have a cross-section of a semicircular shape, and as illustrated in (d) of FIG. 7, the guide protrusion (440) may have a cross-section of an oval shape.

[0112] That is, the guide protrusion (440) may be formed with a side formed on the flange (430) side inclined or formed as a curved shape with a curvature, as described in FIG. 6, so that the reflective sheet (500, see FIG. 13) can be easily fastened. Accordingly, the cross-section of the guide protrusion (440) may be any shape that allows the reflective sheet (500) to be easily fastened, not just the shape shown in FIG. 7.

[0113] In addition, in the case of the cross-section where the upper portion (445) is formed among the several cross-sections of the guide protrusion (440), the angle (θ1) of the upper portion (445) may be 70 degrees or more, as shown in FIG. 8.

[0114] For example, if the angle (θ1) of the upper portion (445) is less than 70 degrees, the upper portion (445) of the guide protrusion (440) may become relatively sharp. In this case, as described in (b) of FIG. 6, the inclination of the first surface (441) formed on the flange (430) side and the second surface (443) formed on the emission surface (420) side of the cross-section of the guide protrusion (440) may increase, and as a result, efficient fastening may be difficult when fastening the reflective sheet (500, see FIG. 13). Therefore, it may be preferable that the angle (θ1) of the upper portion (445) be 70 degrees or more.

[0115] Referring to FIG. 8, the upper end (445) of the guide protrusion (440) may be located on the side of the exit surface (420) (No. 1 guide protrusion (440)) or may be located on the side of the flange (430) (No. 5 guide protrusion (440)). At this time, the position of the upper end (445) of the guide protrusion (440) may be determined depending on the degree to which the reflective sheet (500, see FIG. 13) overlaps the light diffusion lens (400).

[0116] For example, when the amount of overlap between the reflective sheet (500) and the light diffusion lens (400) is large, the upper end (445) of the guide protrusion (440) may be positioned close to the emission surface (420) (see guide protrusion (440) no. 1). Or, for example, when the amount of overlap between the reflective sheet (500) and the light diffusion lens (400) is small, the guide protrusion (440) may be positioned close to the flange (430) (see guide protrusion (440) no. 5).

[0117] That is, the light diffusion lens (400) according to the embodiments has the effect that, when the reflective sheet (500) is combined, the reflective sheet (500) can naturally move downward along the first surface (441) formed on the flange (430) side of the guide protrusion (440), so that the reflective sheet (500) can be easily combined with the LED array bar (310).

[0118] Fig. 9 is a drawing showing an example of the lower surface of a guide protrusion of a light diffusion lens according to embodiments. Fig. 10 is a drawing showing an example of the positions of both ends of a guide protrusion of a light diffusion lens according to embodiments.

[0119] The light diffusion lens (400) illustrated in FIG. 9 corresponds to the light diffusion lens (400) illustrated in FIGS. 5 to 8. The guide protrusion (440) illustrated in FIG. 9 corresponds to the guide protrusion (440) illustrated in FIGS. 5 to 7. The light diffusion lens (400) illustrated in FIG. 10 corresponds to the light diffusion lens (400) illustrated in FIGS. 5 to 7 and FIG. 9. The exit surface (420) illustrated in FIG. 10 corresponds to the exit surfaces (420) illustrated in FIGS. 5, 6, and 8.

[0120] As illustrated in FIG. 9, the guide protrusion (440) may include a lower surface having various shapes. For example, as illustrated in FIGS. 9(a) and (b), the lower surface of the guide protrusion (440) may have a crescent shape (see FIG. 9(a)) or a boomerang shape (see FIG. 9(b)) in which the widths of both ends gradually narrow. That is, the guide protrusion (440) may include a lower surface in which the widths of both ends gradually narrow and the both ends form angles, that is, are formed sharply, as illustrated in FIG. 9(a), or may include a lower surface in which the widths of both ends gradually narrow and the both ends form curvatures, that is, are formed in a curved shape, as illustrated in FIG. 9(b).

[0121] In addition, the guide protrusion (440) may have a circular or elliptical shape on the lower surface, as illustrated in (c) of Fig. 9. In this case, when the guide protrusion (440) has a circular or elliptical shape on the lower surface, a plurality of guide protrusions (440) may be arranged in a row, as illustrated in (c) of Fig. 9 and Fig. 10. More specifically, the guide protrusions (440) may be arranged in a row of two or more and five or less.

[0122] Referring to Fig. 10, the guide protrusion (440) may include a first guide protrusion (440a) located on one side of the exit portion (420) and a second guide protrusion (440b) located on the other side of the exit portion (420) and having point symmetry with the first guide protrusion (440a). In addition, both ends of the first guide protrusion (440a) and the second guide protrusion (440b) may be located within a certain angle (θ2) from the center of the exit portion (420). At this time, it is preferable that the certain angle (θ2) be 120 degrees.

[0123] For example, if both ends of the first guide protrusion (440a) and the second guide protrusion (440b) are positioned at angles exceeding 120 degrees from the center of the emission portion (420), efficient fastening may be difficult when fastening the reflective sheet (500, see FIG. 13). Therefore, it may be preferable that both ends of the first guide protrusion (440a) and the second guide protrusion (440b) be positioned within 120 degrees from the center of the emission portion (420).

[0124] In addition, although Fig. 10 illustrates a case where the lower surface of the guide protrusion (440) is circular, this is only an example, and it will be obvious that this also applies to a case where the lower surface of the guide protrusion (440) has a shape in which the width of both ends gradually narrows as shown in (a) and (b) of Fig. 9.

[0125] Fig. 11 is a drawing showing a total reflection groove of a light diffusion lens according to embodiments.

[0126] The LED array bar (300) illustrated in Fig. 11 corresponds to the LED array bar (300) illustrated in Fig. 5. The light diffusion lens (400) illustrated in Fig. 11 corresponds to Figs. 5 to 7, 9, and 10.

[0127] Referring also to (b) of FIG. 6, the lower surface of the light diffusion lens (400) may be formed with a total reflection groove (414) that is positioned around the entrance port (410) and is concavely recessed upward. At this time, the degree of recessing may be determined depending on whether the light emitted from the LED (310) is 100% totally reflected. That is, the light emitted from the LED (310) may be reflected in the total reflection groove (414), and more specifically, the light emitted from the LED (310) may be 100% totally reflected in the total reflection groove (414).

[0128] Accordingly, the light diffusion lens (400) according to the embodiments has the effect of allowing all light emitted from the LED (310) to be emitted from the emission surface (420).

[0129] More specifically, the total reflection groove (414) may include an inclined surface (416) extending upward from the entrance port (410). The inclination and height of the inclined surface (416) may be determined depending on the position of the cross-section of the guide protrusion (440), more specifically, the degree of inclination of the second surface (443) of the guide protrusion (440).

[0130] That is, as illustrated in FIG. 11, light emitted from the LED (310) is reflected (more specifically, totally reflected) by an inclined surface (416) having a constant slope, and at this time, the position of the cross-section of the guide protrusion (440), more specifically, the degree of inclination of the second surface (443) of the guide protrusion (440), can be determined so that the reflected light does not pass through the guide protrusion (440) (so that it is not interfered with by the guide protrusion (440).

[0131] For example, the position of the cross-section of the guide protrusion (440), more specifically, the degree of inclination of the second surface (443) of the guide protrusion (440), can be determined so that light reflected by the incline surface (416) can pass by, or can be determined so that light reflected by the incline surface (416) can pass by a certain distance from the second surface (443).

[0132] Fig. 12 is a drawing showing a state in which a light diffusion lens and a reflective sheet according to embodiments are viewed from above.

[0133] The LED array bar (300) illustrated in Fig. 12 corresponds to the LED array bar (300) illustrated in Figs. 5 and 11. The light diffusion lens (400) illustrated in Fig. 12 corresponds to the light diffusion lens (400) illustrated in Figs. 5 to 7 and Figs. 9 to 11.

[0134] As illustrated in FIG. 12, a reflective sheet (500) may be mounted on an LED array bar (300), and a plurality of holes (510) may be formed in the reflective sheet (500) corresponding to the positions of the LEDs (310) and the light diffusion lenses (400) surrounding the LEDs (310). At this time, it is preferable that the number of holes (510) be formed to be the same as the number of LEDs (310) and the light diffusion lenses (400).

[0135] At this time, the hole (510) may have a size and shape such that at least a portion of the guide protrusion (440) can overlap with the reflective sheet (500). More specifically, the guide protrusion (440) may have a side formed on the flange (430) side with respect to the upper end (445) that can overlap with the reflective sheet (500), and a side formed on the emission surface (420) side with respect to the upper end (445) that does not overlap with the reflective sheet (500).

[0136] In other words, referring to (b) of FIG. 6, at least a portion of the first surface (441) formed on the flange (430) side based on the upper portion (445) of the cross-section of the guide protrusion (440) can overlap with the reflective sheet (500).

[0137] The hole (510) may have a pair of straight boundaries (510a) formed to face each other on both sides and a pair of curved boundaries (510b) formed to connect both ends of the straight boundaries and face each other on both sides.

[0138] As illustrated in Fig. 12, a straight boundary (510a) may be formed on both sides of the first direction, such as a plurality of LEDs (310) spaced apart from each other in the first direction and a light diffusion lens (400) surrounding the LEDs (310). In addition, a curved boundary (510b) may be formed on both sides of the second direction that is perpendicular to the first direction.

[0139] Furthermore, Fig. 12 is merely an example; a straight boundary (510a) may be formed on both sides in the second direction, and a curved boundary (510b) may be formed on both sides in the first direction. Alternatively, a straight boundary (510a) and a curved boundary (510b) may be formed on both sides in a certain direction other than the first and second directions.

[0140] At this time, it is preferable that the guide protrusion (440) be formed at a position overlapping the straight boundary (510a). That is, the straight boundary (510a) of the hole (510) may be formed at a position where it meets the guide protrusion (440). More specifically, the straight boundary (510a) of the hole (510) may be formed at a position where the upper end (445) of the guide protrusion (440) meets it.

[0141] Therefore, the reflective sheet (500) can overlap at least a portion of the guide protrusion (440).

[0142] Fig. 13 is a drawing showing a state in which a reflective sheet of a backlight unit according to embodiments is combined.

[0143] The LED array bar (300) illustrated in Fig. 13 corresponds to the LED array bar (300) illustrated in Figs. 5, 11, and 12. The light diffusion lens (400) illustrated in Fig. 13 corresponds to the light diffusion lens (400) illustrated in Figs. 5 to 7 and 9 to 12. The reflective sheet (500) illustrated in Fig. 13 corresponds to the reflective sheet (500) illustrated in Fig. 12.

[0144] Referring to FIG. 13, the reflective sheet (500) does not touch the exit surface (420) and the flange (430) by the guide protrusion (440), and as a result, the light diffusion lens (400) according to the embodiments has the effect of not causing scratches on the exit surface (420) and the flange (430) even when the reflective sheet (500) is coupled to the LED array bar (310).

[0145] In addition, since the light diffusion lenses (400) according to the embodiments are formed in a pair facing each other, when the reflective sheet (500) is joined to the LED array bar (310), there is an effect that the reflective sheet (500) can be easily joined to the LED array bar (310) without causing scratches on the emission surface (420) and the flange (430) by applying force in one direction using a roller or the like in the direction in which the light diffusion lenses (400) are formed.

[0146] More specifically, the reflective sheet (500) can meet the side formed on the flange (430) side based on the upper end (445) of the guide protrusion (440). That is, when the reflective sheet (500) is fastened, the reflective sheet (500) can meet the side formed on the flange (430) side so that the reflective sheet (500) is completely fastened.

[0147] Referring to (b) of FIG. 6, the reflective sheet (500) can be positioned to overlap with the first surface (441) formed on the flange (430) side of the cross-section of the guide protrusion (440), and the reflective sheet (500) can move downward by an applied external force (arrow) due to the inclination of the first surface (441).

[0148] Accordingly, as described above in FIG. 8, when the degree of overlap between the reflective sheet (500) and the light diffusion lens (400) is large, the upper end (445) of the guide protrusion (440) is positioned on the side of the emission surface (420), and when the degree of overlap between the reflective sheet (500) and the light diffusion lens (400) is small, the upper end (445) of the guide protrusion (440) is positioned on the side of the flange (430).

[0149]

[0150] The detailed description of the preferred embodiments of the present invention disclosed above has been provided to enable those skilled in the art to implement and practice the present invention. While the above description has been made with reference to preferred embodiments of the present invention, those skilled in the art will appreciate that various modifications and variations can be made to the present invention without departing from the scope of the present invention. For example, those skilled in the art can utilize the individual components described in the above-described embodiments in combination with each other.

[0151] Accordingly, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. For the light diffusion lens covering the LED, A circular entrance port formed on the lower surface of the light diffusion lens and accommodating the LED; An incident surface convexly introduced upward from the above-mentioned entrance port; An exit surface positioned above the incident surface and protruding in a dome shape on the upper surface of the light diffusion lens; A flange protruding laterally from the lower end of the above-mentioned projection surface; and A light diffusion lens characterized by including a guide protrusion protruding upward from the upper surface of the flange.

2. In paragraph 1, A light diffusion lens characterized in that the cross-sectional area of ​​the above guide protrusion decreases from the bottom to the top.

3. In paragraph 1, A light diffusion lens, characterized in that the height of the guide protrusion is smaller than the height of the emission surface.

4. In paragraph 1, A light diffusion lens, characterized in that at least a portion of the lower edge of the guide protrusion is in contact with the edge of the flange.

5. In paragraph 1, It further includes a total reflection groove positioned around the periphery of the above entrance and concavely recessed upward, A light diffusion lens characterized in that the above total reflection groove includes an inclined surface extending in a direction toward the upper side from the entrance port.

6. In paragraph 1, A light diffusion lens, characterized in that the angle formed by the upper part of the above guide protrusion is 70 degrees or greater.

7. In paragraph 1, A light diffusion lens characterized in that the width of both ends of the above guide protrusion gradually narrows toward both ends.

8. In paragraph 1, A light diffusion lens characterized in that the above guide protrusions are arranged in a plurality of rows.

9. In paragraph 8, A light diffusion lens characterized in that the lower surface of the above guide protrusion has an elliptical shape or a circular shape.

10. In paragraph 1, The above guide protrusions are, A first guide projection located on one side of the above-mentioned projection part; and A light diffusion lens characterized by including a second guide protrusion positioned on the other side of the above-mentioned emission portion and having a point symmetry with the first guide protrusion.

11. In paragraph 9, A light diffusion lens, characterized in that both ends of the first guide protrusion and the second guide protrusion are formed within 120 degrees from the center of the emission portion.

12. An LED array bar comprising a plurality of LEDs spaced apart from each other in a first direction; A light diffusion lens formed on the LED array bar to cover each of the LEDs; and A reflective sheet is mounted on the LED array bar and has a plurality of holes formed corresponding to the LEDs, The above light diffusion lens, A circular entrance port formed on the lower surface of the light diffusion lens and accommodating the LED; An incident surface convexly introduced upward from the above-mentioned entrance port; An exit surface positioned above the incident surface and protruding in a dome shape on the upper surface of the light diffusion lens; A flange protruding laterally from the lower end of the above-mentioned projection surface; and Including a protective guide projection protruding upward from the upper surface of the above flange, A backlight unit, characterized in that at least a portion of the above guide protrusion overlaps the above reflective sheet.

13. In paragraph 11, The above hall is, Having a pair of straight boundaries formed to face each other on both sides and a pair of curved boundaries formed to face each other on both sides and connecting both ends of the straight boundaries, A backlight unit characterized in that the above guide protrusion is formed at a position overlapping the above straight boundary.

14. In paragraph 13, A backlight unit characterized in that the upper part of the above guide protrusion is formed at a position where it meets the above straight boundary.

15. In paragraph 11, The cross-sectional area of ​​the above guide protrusion decreases from the bottom to the top. The height of the above guide projection is smaller than the height of the above exit surface, A backlight unit characterized in that at least a portion of the lower edge of the guide protrusion is in contact with the edge of the flange.

16. In paragraph 11, A backlight unit characterized in that a joining hole is formed on the LED array bar to which the light diffusion lens is joined.

17. In paragraph 11, The LED array bars are arranged in multiple numbers in the second direction perpendicular to the first direction, A backlight unit characterized in that the above reflective sheet covers the plurality of LED array bars simultaneously.

18. Display panel; A frame positioned at the rear of the above display panel; An LED array bar positioned between the display panel and the frame, the LED array bar including a plurality of LEDs providing light to the display panel; A light diffusion lens formed on the LED array bar to cover each of the LEDs; and A reflective sheet is mounted on the LED array bar and has a plurality of holes formed corresponding to the LEDs, The above plurality of LEDs are arranged spaced apart from each other in the first direction, The above light diffusion lens, A circular entrance port formed on the lower surface of the light diffusion lens and accommodating the LED; An incident surface convexly introduced upward from the above-mentioned entrance port; An exit surface positioned above the incident surface and protruding in a dome shape on the upper surface of the light diffusion lens; A flange protruding laterally from the lower end of the above-mentioned projection surface; and Including a protective guide projection protruding upward from the upper surface of the above flange, A display device, characterized in that at least a portion of the guide protrusion overlaps the reflective sheet.

Images