Display apparatus

Abstract

A display device is disclosed that includes a backlight unit that reduces production costs by reducing the amount of quantum dot resin used. The display device includes a liquid crystal panel and a backlight unit that provides light to the liquid crystal panel. The backlight unit may include a substrate, a light-emitting diode mounted on the substrate, a quantum dot cover provided to cover the light-emitting diode and convert the wavelength of light emitted from the light-emitting diode, a refraction cover covering the light-emitting diode and the quantum dot cover, wherein a recess is provided in the center of the upper surface and is recessed toward the quantum dot cover, and a reflective layer that is disposed on the upper side of the quantum dot cover by being provided in the recess and has a lower surface diameter smaller than the upper surface diameter.

Description

Technology Field

[0001] The present disclosure relates to a display device comprising a backlight unit and a liquid crystal panel. Background Technology

[0002] Generally, a display device is a type of output device that converts acquired or stored electrical information into visual information and displays it to a user, and is used in various fields such as homes and workplaces.

[0003] Display devices include monitor devices connected to personal computers or server computers, portable computer devices, navigation terminal devices, general television devices, Internet Protocol Television (IPTV) devices, portable terminal devices such as smartphones, tablet PCs, Personal Digital Assistants (PDAs), or cellular phones, various display devices used to play images such as advertisements or movies in industrial settings, or various other types of audio / video systems.

[0004] The display device may include a backlight unit (BLU) that provides light to a liquid crystal panel. The backlight unit may include a plurality of point light sources capable of emitting light independently. The problem to be solved

[0005] One aspect of the present disclosure provides a display device comprising a backlight unit with improved productivity and reduced cost.

[0006] One aspect of the present disclosure provides a display device including a backlight unit that reduces production costs by reducing the amount of quantum dot resin used.

[0007] One aspect of the present disclosure provides a display device comprising a light source having a light profile with a high directional angle. means of solving the problem

[0008] A display device according to one example of the present disclosure includes a liquid crystal panel and a backlight unit that provides light to the liquid crystal panel, wherein the backlight unit comprises a substrate, a light-emitting diode mounted on the substrate, a quantum dot cover provided to cover the light-emitting diode and convert the wavelength of light emitted from the light-emitting diode, a refraction cover covering the light-emitting diode and the quantum dot cover, wherein a recess is provided in the center of the upper surface and is recessed toward the quantum dot cover, and a reflective layer disposed on the upper side of the quantum dot cover by being provided in the recess, and wherein the diameter of the lower surface is formed to be smaller than the diameter of the upper surface.

[0009] The above-mentioned refraction cover may be provided to have a maximum height at a point spaced a predetermined distance in the horizontal direction from the center of the light-emitting diode.

[0010] The above-mentioned bending cover may be provided to have an upwardly convex shape at the maximum height.

[0011] The above-mentioned refraction cover may have a rotationally symmetric shape.

[0012] The lower surface of the above-mentioned reflective layer can be provided with a convex shape facing upward.

[0013] The diameter of the lower surface of the above-mentioned reflective layer may be larger than the diameter of the lower surface of the above-mentioned quantum dot cover.

[0014] The lower surface of the above-mentioned reflective layer can be provided as a flat surface.

[0015] A glass bead array or a microprism array may be provided on the lower surface of the above-mentioned reflective layer.

[0016] The above backlight unit may further include a lower reflective layer formed by applying a PSR (Photo Solder Resist) on the substrate.

[0017] Let Lr be the horizontal distance from the center of the light-emitting diode to the outermost point of the reflective layer where the marginal ray passing through the refraction cover contacts, and let H be the vertical distance between the outermost point of the reflective layer and the lower reflective layer, then 10˚ < tan -1 (H / Lr) may be < 70˚.

[0018] The light-emitting diode can be mounted on the substrate using a Chip On Board (COB) method.

[0019] The light-emitting diode described above can be configured to emit blue light.

[0020] The above quantum dot cover may be configured to convert a portion of the blue light emitted from the light-emitting diode into red light and green light.

[0021] The above quantum dot cover can be formed by dispensing and curing a liquid quantum dot resin.

[0022] The above-mentioned refraction cover can be formed by dispensing and curing a transparent material in a liquid state.

[0023] The above reflective layer can be formed by dispensing and curing a liquid reflective material. Effects of the invention

[0024] According to the present disclosure, a display device including a backlight unit with improved productivity and reduced cost can be provided.

[0025] According to the present disclosure, a display device including a backlight unit that reduces production costs by reducing the amount of quantum dot resin used can be provided.

[0026] According to the present disclosure, a display device comprising a light source having a high directional angle light profile can be provided. Brief explanation of the drawing

[0027] FIG. 1 illustrates an example of the appearance of a display device according to one embodiment. FIG. 2 illustrates an example of the structure of a display device according to one embodiment. FIG. 3 illustrates an example of a liquid crystal panel included in a display device according to one embodiment. FIG. 4 illustrates an example of a backlight unit included in a display device according to one embodiment. FIG. 5 schematically illustrates an example of a light source included in a backlight unit according to one embodiment. FIG. 6 illustrates an example of a light-emitting diode included in a backlight unit according to one embodiment. FIG. 7 illustrates an example of a cross-section according to AA of FIG. 6. FIG. 8 illustrates an example of a light profile emitted from a light source of a backlight unit according to one embodiment. FIG. 9 illustrates the emission spectrum according to the presence or absence of a reflective layer in a light source of a backlight unit according to one embodiment. FIG. 10 illustrates another example of a cross-section according to AA of FIG. 5. FIG. 11 illustrates another example of a cross-section according to AA of FIG. 5. Figure 12 illustrates the light path on the underside of the reflective layer shown in Figure 11. FIG. 13 illustrates another example of a cross-section according to AA of FIG. 5. FIG. 14 illustrates a microprism array provided on the lower surface of the reflective layer shown in FIG. 13. FIG. 15 schematically illustrates the light path on the underside of the reflective layer shown in FIG. 13. FIG. 16 schematically illustrates an example of a method for manufacturing a light source of a backlight unit according to one embodiment. FIG. 17 schematically illustrates another example of a method for manufacturing a light source of a backlight unit according to one embodiment. FIG. 18 schematically illustrates a method for forming a quantum dot cover in a method for manufacturing a light source of a backlight unit according to one embodiment. FIG. 19 schematically illustrates a method for forming a refractive cover in a method for manufacturing a light source of a backlight unit according to one embodiment. FIG. 20 schematically illustrates a method for forming a reflective layer in a method for manufacturing a light source of a backlight unit according to one embodiment. Specific details for implementing the invention

[0028] The embodiments described in this specification and the configurations illustrated in the drawings are merely preferred examples of the disclosed invention, and various modifications that may replace the embodiments and drawings of this specification may exist at the time of filing this application.

[0029] Additionally, the same reference numerals or symbols presented in each drawing of this specification represent parts or components that perform substantially the same function.

[0030] Furthermore, the terms used in this specification are for describing embodiments and are not intended to limit or / or restrict the disclosed invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "comprising" or "having" are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and do not preclude the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0031] Additionally, terms including ordinal numbers, such as "first," "second," etc., as used herein may be used to describe various components, but said components are not limited by said terms, and said terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be named the second component, and similarly, the second component may be named the first component. The term "and / or" includes a combination of a plurality of related described items or any one of a plurality of related described items.

[0032] Hereinafter, embodiments according to the present invention will be described in detail with reference to the attached drawings.

[0033] FIG. 1 illustrates an example of the appearance of a display device according to one embodiment.

[0034] Referring to FIG. 1, the display device (10) is a device capable of processing a video signal received from the outside and visually displaying the processed video. In the following examples, the display device (10) is exemplified as a television (TV), but is not limited thereto. For example, the display device (10) can be implemented in various forms such as a monitor, a portable multimedia device, a portable communication device, etc., and the form of the display device (10) is not limited as long as it is a device that visually displays video.

[0035] In addition, the display device (10) may be a large format display (LFD) installed outdoors, such as on a building rooftop or at a bus stop. Here, the outdoors is not necessarily limited to an open area and may include indoor spaces where many people can enter and exit, such as subway stations, shopping malls, movie theaters, companies, and shops.

[0036] The display device (10) receives content including video signals and audio signals from various content sources and can output video and audio corresponding to the video signals and audio signals. For example, the display device (10) can receive content data through a broadcast receiving antenna or a wired cable, receive content data from a content playback device, or receive content data from a content provider's content provision server.

[0037] As illustrated in FIG. 1, the display device (10) may include a main body (11) and a screen (12) that displays an image (I).

[0038] The main body (11) forms the outer shape of the display device (10), and components for the display device (10) to display an image (I) or perform various functions may be provided inside the main body (11). The main body (11) shown in FIG. 1 is in the shape of a flat plate, but the shape of the main body (11) is not limited to that shown in FIG. 1. For example, the main body (11) may be in the shape of a curved plate.

[0039] A screen (12) is formed on the front of the main body (11) and can display an image (I). For example, the screen (12) can display a still image or a video. Additionally, the screen (12) can display a two-dimensional flat image or a three-dimensional stereoscopic image using the parallax of the user's two eyes.

[0040] The screen (12) may include a non-emissive panel (e.g., a liquid crystal panel) capable of passing through or blocking light emitted by a backlight unit (BLU), etc.

[0041] A plurality of pixels (P) are formed on the screen (12), and an image (I) displayed on the screen (12) can be formed by light emitted by each of the plurality of pixels (P). For example, an image (I) can be formed on the screen (12) by combining the light emitted by each of the plurality of pixels (P) as if in a mosaic.

[0042] Each of the plurality of pixels (P) can emit light of various brightness and various colors. In order to emit light of various colors, each of the plurality of pixels (P) may include subpixels (PR, PG, PB).

[0043] The subpixels (PR, PG, PB) may include a red subpixel (PR) capable of emitting red light, a green subpixel (PG) capable of emitting green light, and a blue subpixel (PB) capable of emitting blue light. For example, red light may represent light with a wavelength of approximately 620 nm (nanometer, one-billionth of a meter) to 750 nm. Green light may represent light with a wavelength of approximately 495 nm to 570 nm. Blue light may represent light with a wavelength of approximately 450 nm to 495 nm.

[0044] By combining the red light of the red subpixel (PR), the green light of the green subpixel (PG), and the blue light of the blue subpixel (PB), light of various brightness and various colors can be emitted from each of the multiple pixels (P).

[0045] FIG. 2 illustrates an example of the structure of a display device (10) according to one embodiment, and FIG. 3 illustrates an example of a liquid crystal panel included in a display device (10) according to one embodiment.

[0046] As shown in FIG. 2, various components for generating an image (I) on a screen (S) may be provided inside the main body (11).

[0047] For example, the main body (11) is provided with a back light unit (BLU) (100) which is a surface light source, a liquid crystal panel (20) that blocks or passes light emitted from the back light unit (100), a control assembly (50) that controls the operation of the back light unit (100) and the liquid crystal panel (20), and a power assembly (60) that supplies power to the back light unit (100) and the liquid crystal panel (20). Additionally, the main body (11) may include a bezel (13) for supporting the liquid crystal panel (20), the back light unit (100), the control assembly (50), and the power assembly (60), a frame middle mold (14), a bottom chassis (15), and a rear cover (16).

[0048] The backlight unit (100) may include a point light source that emits white light. The point light source may include a device that emits monochromatic light and a quantum dot cover that converts the monochromatic light emitted from the device into white light. For example, the point light source may include a light-emitting diode (LED) that emits blue light and a quantum dot cover that converts a portion of the blue light emitted from the light-emitting diode into red light and green light. The quantum dot cover can convert a portion of the blue light into red light and green light by changing the wavelength of a portion of the blue light. Through this, the blue light emitted from the light-emitting diode can become white light as it passes through the quantum dot cover.

[0049] The backlight unit (100) can refract, reflect, and scatter light to convert light emitted from a point light source into uniform surface light. In this way, the backlight unit (100) can emit uniform surface light toward the front by refracting, reflecting, and scattering light emitted from a point light source.

[0050] The backlight unit (100) is described in more detail below.

[0051] A liquid crystal panel (20) is provided in front of a backlight unit (100) and blocks or passes light emitted from the backlight unit (100) to form an image (I).

[0052] The front surface of the liquid crystal panel (20) forms the screen (S) of the display device (10) described above, and the liquid crystal panel (20) can form a plurality of pixels (P). The plurality of pixels (P) of the liquid crystal panel (20) can each independently block or allow light from the backlight unit (100) to pass through. In addition, the light passed through the plurality of pixels (P) can form an image (I) displayed on the screen (S).

[0053] For example, as shown in FIG. 3, the liquid crystal panel (20) may include a first polarizing film (21), a first transparent substrate (22), a pixel electrode (23), a thin film transistor (24), a liquid crystal layer (25), a common electrode (26), a color filter (27), a second transparent substrate (28), and a second polarizing film (29).

[0054] The first transparent substrate (22) and the second transparent substrate (28) can fix and support a pixel electrode (23), a thin-film transistor (24), a liquid crystal layer (25), a common electrode (26), and a color filter (27). These first and second transparent substrates (22, 28) may be composed of reinforced glass or a transparent resin.

[0055] A first polarizing film (21) and a second polarizing film (29) are provided on the outer side of the first and second transparent substrates (22, 28). The first polarizing film (21) and the second polarizing film (29) can each pass specific polarization and block (reflect or absorb) other polarization. For example, the first polarizing film (21) can pass polarization of a first direction and block (reflect or absorb) other polarization. Also, the second polarizing film (29) can pass polarization of a second direction and block (reflect or absorb) other polarization. At this time, the first direction and the second direction may be orthogonal to each other. As a result, polarization that has passed through the first polarizing film (21) cannot directly pass through the second polarizing film (29).

[0056] A color filter (27) may be provided on the inner side of the second transparent substrate (28). The color filter (27) may include, for example, a red filter (27R) that passes red light, a green filter (27G) that passes green light, and a blue filter (27B) that passes blue light. Additionally, the red filter (27R), the green filter (27G), and the blue filter (27B) may be arranged side by side. The area occupied by the color filter (27) corresponds to the pixel (P) described above. The area occupied by the red filter (27R) corresponds to the red subpixel (PR), the area occupied by the green filter (27G) corresponds to the green subpixel (PG), and the area occupied by the blue filter (27B) corresponds to the blue subpixel (PB).

[0057] The pixel electrode (23) may be provided on the inner side of the first transparent substrate (22), and the common electrode (26) may be provided on the inner side of the second transparent substrate (28). The pixel electrode (23) and the common electrode (26) are made of an electrically conductive metal material and can generate an electric field to change the arrangement of liquid crystal molecules (115a) constituting the liquid crystal layer (25) described below.

[0058] A thin film transistor (TFT) (24) is provided on the inner side of the second transparent substrate (22). The thin film transistor (24) can be turned on (closed) or turned off (open) by image data provided from the panel driver (30). Additionally, depending on the turn-on (closed) or turn-off (open) of the thin film transistor (24), an electric field can be formed or removed between the pixel electrode (23) and the common electrode (26).

[0059] The liquid crystal layer (25) is formed between the pixel electrode (23) and the common electrode (26) and is filled with liquid crystal molecules (25a). The liquid crystal may exhibit an intermediate state between a solid (crystal) and a liquid. The liquid crystal may exhibit optical properties depending on changes in the electric field. For example, the direction of the molecular arrangement constituting the liquid crystal may change depending on changes in the electric field. Consequently, the optical properties of the liquid crystal layer (25) may vary depending on the presence or absence of the electric field passing through the liquid crystal layer (25). For example, the liquid crystal layer (25) may rotate the polarization direction of light around the optical axis depending on the presence or absence of the electric field. Accordingly, the polarization that has passed through the first polarizing film (21) has its polarization direction rotated while passing through the liquid crystal layer (25) and can pass through the second polarizing film (29).

[0060] On one side of the liquid crystal panel (20), a cable (20a) for transmitting image data to the liquid crystal panel (20) and a display driver integrated circuit (DDI) (30) (hereinafter referred to as 'panel driver') for processing digital image data and outputting an analog image signal are provided.

[0061] The cable (20a) electrically connects the control assembly (50) and the power assembly (60) with the panel driver (30), and can also electrically connect the panel driver (30) with the liquid crystal panel (20). The cable (20a) may include a flexible flat cable or a film cable, etc.

[0062] The panel driver (30) can receive image data and power from the control assembly (50) and the power assembly (60) through the cable (20a). The panel driver (30) can provide image data and driving current to the liquid crystal panel (20) through the cable (20a).

[0063] The cable (20a) and the panel driver (30) can be implemented as a single unit using a film cable, a chip on film (COF), a tape carrier packet (TCP), etc. In other words, the panel driver (30) can be placed on the cable (20b). However, it is not limited thereto, and the panel driver (30) can be placed on the liquid crystal panel (20).

[0064] The control assembly (50) may include a control circuit that controls the operation of the liquid crystal panel (20) and the backlight unit (100). For example, the control circuit may process video signals and / or audio signals received from an external content source. The control circuit may transmit video data to the liquid crystal panel (20) and dimming data to the backlight unit (100).

[0065] The power assembly (60) may include a power circuit that supplies power to the liquid crystal panel (20) and the backlight unit (100). The power circuit may supply power to the control assembly (50), the backlight unit (100), and the liquid crystal panel (20).

[0066] The control assembly (50) and the power assembly (60) may be implemented with a printed circuit board and various circuits mounted on the printed circuit board. For example, the power circuit may include a capacitor, a coil, a resistor, a processor, etc., and a power circuit board on which these are mounted. Additionally, the control circuit may include a memory, a processor, and a control circuit board on which these are mounted.

[0067] FIG. 4 illustrates an example of a backlight unit included in a display device according to one embodiment. FIG. 5 schematically illustrates an example of a light source included in a backlight unit according to one embodiment.

[0068] As illustrated in FIG. 4, the backlight unit (100) may include a light source module (110) that generates light, a diffuser plate (130) that diffuses light uniformly, and an optical sheet (140) that improves the brightness of the emitted light.

[0069] The light source module (110) may include a plurality of light sources (111) that emit light and a substrate (112) that supports and fixes the plurality of light sources (111).

[0070] Multiple light sources (111) can be arranged in a predetermined pattern so that light is emitted with uniform brightness. Multiple light sources (111) can be arranged so that the distance between one light source and adjacent light sources becomes equal.

[0071] For example, as illustrated in FIG. 4, a plurality of light sources (111) can be arranged in rows and columns. Accordingly, a plurality of light sources can be arranged so that a square is formed by four adjacent light sources. Additionally, one light source is placed adjacent to four light sources, and the distance between one light source and the four adjacent light sources can be approximately equal.

[0072] Multiple light sources may be arranged so that an equilateral triangle is formed by three adjacent light sources. In this case, one light source may be placed adjacent to six light sources. Also, the distance between one light source and the six adjacent light sources may be approximately equal.

[0073] However, the arrangement of the plurality of light sources (111) is not limited to the arrangement described above, and the plurality of light sources (111) can be arranged in various ways so that light is emitted with uniform brightness.

[0074] The light source (111) may employ a device capable of emitting monochromatic light (light having a specific range of wavelengths or light having a single peak wavelength, e.g., blue light) in various directions when power is supplied.

[0075] As shown in FIG. 5, each of the plurality of light sources (111) may include a light-emitting diode (LED) (190), a quantum dot cover (160), a refractive cover (170), and a reflective layer (180).

[0076] The light-emitting diode (190) can be directly attached to the substrate (112) in a Chip On Board (COB) manner. For example, the light source (111) may include a light-emitting diode (190) in which a light-emitting diode chip or a light-emitting diode die is directly attached to the substrate (112) without separate packaging.

[0077] The light-emitting diode (190) can be manufactured as a flip-chip type. When attaching the light-emitting diode (190), which is a semiconductor device, to the substrate (112), the electrode pattern of the semiconductor device can be fused directly to the substrate (112) without using an intermediate medium such as a metal lead (wire) or a ball grid array (BGA). In this way, as the metal lead (wire) or ball grid array is omitted, the light source (111) including the flip-chip type light-emitting diode (190) can be miniaturized.

[0078] The light-emitting diode (190) may be configured to emit monochromatic light. According to one embodiment, the light-emitting diode (190) may be configured to emit blue light. The blue light emitted from the light-emitting diode (190) may be converted into white light as it passes through the quantum dot cover (160). However, it is not limited thereto, and the light-emitting diode may be configured to emit red light or green light.

[0079] The quantum dot cover (160) can cover the light-emitting diode (190). The quantum dot cover (160) can prevent or suppress damage to the light-emitting diode (190) caused by external mechanical action and / or damage to the light-emitting diode (190) caused by chemical action.

[0080] The quantum dot cover (160) can convert the wavelength of monochromatic light emitted from the light-emitting diode (190). The quantum dot cover (160) can convert monochromatic light into white light by converting the wavelength of monochromatic light emitted from the light-emitting diode (190).

[0081] For example, the light-emitting diode (190) can emit blue light, and the quantum dot cover (160) can convert some of the blue light into red light and green light by converting the wavelength of some of the blue light. As some of the blue light emitted from the light-emitting diode (190) passes through the quantum dot cover (160) and is converted into red light and green light, the light emitted from the quantum dot cover (160) can become white light. Accordingly, the light source module (110) according to the present disclosure may include a light source (111) that emits white light.

[0082] According to one embodiment, the quantum dot cover (160) can be formed by curing a liquid quantum dot resin after it has been dispensed or jetted. The quantum dot cover (160) can be formed by curing alone without any separate processing after dispensing or jetting. In other words, the quantum dot cover (160) can be said to be self-forming.

[0083] A quantum dot cover (160) may be provided to surround the top surface and four sides of the light-emitting diode (190). The quantum dot cover (160) may be formed by curing after dispensing or jetting a liquid quantum dot resin to cover all four sides of the light-emitting diode (190).

[0084] The refractive cover (170) can cover the quantum dot cover (160). The refractive cover (170) can prevent or suppress damage to the quantum dot cover (160) caused by external mechanical action and / or damage to the quantum dot cover (160) caused by chemical action.

[0085] According to one embodiment, the refraction cover (170) may be provided in a dome shape including a recess in the center. More specifically, the refraction cover (170) may be provided in a rotationally symmetric shape having a circle shape on its lower surface and a maximum height (h, see FIG. 7) at a point spaced a predetermined distance in the horizontal direction from the center of the lower surface. The periphery of the point (P, see FIG. 7) having the maximum height (h) on the refraction cover (170) may be provided in a shape that is convex upward with respect to the radial direction of the refraction cover (170).

[0086] The refraction cover (170) may be composed of silicone or epoxy resin. For example, molten silicone or epoxy resin may be dispensed in a liquid state onto the quantum dot cover (160) through a nozzle, and the dispensed silicone or epoxy resin may then be cured to form the refraction cover (170).

[0087] According to one embodiment, the refraction cover (170) can be formed by dispensing a transparent liquid material at a plurality of spaced-apart points and then curing it. The refraction cover (170) can be formed by curing alone without any separate treatment after dispensing. In other words, the refraction cover (170) can be said to be self-forming.

[0088] The refractive cover (170) may be provided to be optically transparent or translucent. Light emitted from the light-emitting diode (190) may pass through the quantum dot cover (160) and the refractive cover (170) and be emitted to the outside.

[0089] At this time, the refractive cover (170) can refract light like a lens. For example, light emitted from the light-emitting diode (190) to the outside of the quantum dot cover (160) can be dispersed by being refracted by the refractive cover (170).

[0090] In this way, the refractive cover (170) can disperse light emitted outside the quantum dot cover (160) by covering the quantum dot cover (160).

[0091] The substrate (112) can fix a plurality of light sources (111) so that the position of the light source (111) is not changed. In addition, the substrate (112) can supply power to each light source (111) for the light source (111) to emit light.

[0092] A substrate (112) can fix a plurality of light sources (111). The substrate (112) may be composed of a synthetic resin, reinforced glass, or a printed circuit board (PCB) having a conductive power supply line formed therein to supply power to the light sources (111).

[0093] A lower reflective layer (113) may be provided on the upper surface of the substrate (112). The lower reflective layer (113) may include a Photo Solder Resist (PSR) coated on the upper surface of the substrate (112). The lower reflective layer (113) may be provided to reflect light reflected from the reflective layer (180), which will be described later, toward the lower reflective layer (113) forward.

[0094] A plurality of light-emitting diodes (190) can be provided on the upper surface of the substrate (112) to form an array. Quantum dot covers (160) can be provided in a plurality to correspond to each of the plurality of light-emitting diodes (190). Likewise, refraction covers (170) can be provided in a plurality to correspond to each of the plurality of quantum dot covers (160).

[0095] According to one embodiment, a reflective layer (180) may be provided in a recess formed in the center of the refractive cover (170). The recess may be provided in the center of the refractive cover (170) and may be recessed toward the quantum dot cover (160).

[0096] The reflective layer (180) may be provided to reflect a portion of the light incident from the light-emitting diode (190) through the quantum dot cover (160) and the refractive cover (170) to the reflective layer (180). The reflective layer (180) may be located above the quantum dot cover (160). The reflective layer (180) may be positioned at a predetermined distance in a vertical direction from the quantum dot cover (160). Depending on various embodiments, the distance between the reflective layer (180) and the quantum dot cover (160) may be changed. The reflective layer (180) may be provided such that the area of ​​its upper or lower surface is larger than the area of ​​the lower surface of the quantum dot cover (160). The reflective layer (180) may be formed such that the diameter of its upper surface is larger than the diameter of its lower surface. In other words, the reflective layer (180) may be formed such that the diameter of its lower surface is smaller than the diameter of its upper surface. The reflective layer (180) can be formed by dispensing a liquid reflective material into the recess of the refraction cover (170) and then curing it. Accordingly, the shape of the reflective layer (180) can be determined by the shape of the recess of the refraction cover (170). According to various embodiments, the shape of the recess of the refraction cover (170) can be changed to change the shape of the reflective layer (180) within a predetermined range.

[0097] According to one embodiment, unlike that shown in FIG. 4, the substrate may be provided in a bar shape by extending in one direction. In this case, a plurality of light-emitting diodes may form an array by being spaced apart in the direction in which the substrate extends. A plurality of bar-shaped substrates may be provided. The plurality of substrates may be spaced apart from each other along a direction perpendicular to the direction in which the substrate extends. For example, the bar-shaped substrate may extend along the horizontal direction, and the plurality of substrates may be spaced apart along the vertical direction.

[0098] A diffuser plate (130) may be provided in front of the light source module (110). The diffuser plate (130) can evenly disperse light emitted from the light source (111) of the light source module (110).

[0099] The diffuser plate (130) can diffuse light emitted from a plurality of light sources (111) within the diffuser plate (130) to reduce the non-uniformity of brightness caused by the plurality of light sources (111). In other words, the diffuser plate (130) can diffuse the non-uniform light emitted from the plurality of light sources (111) so that it can be emitted relatively uniformly to the front.

[0100] The optical sheet (140) may include various sheets to improve brightness and also improve the uniformity of brightness. For example, the optical sheet (140) may include a light conversion sheet (141), a diffusion sheet (142), a prism sheet (143), a reflective polarizing sheet (144), etc.

[0101] The optical sheet (140) is not limited to the sheet or film shown in FIG. 4 and may include a wider variety of sheets or films, such as a protective sheet.

[0102] FIG. 6 illustrates an example of a light-emitting diode included in a backlight unit according to one embodiment.

[0103] Referring to FIG. 6, the light-emitting diode (190) may include a transparent substrate (195), an n-type semiconductor layer (193), and a p-type semiconductor layer (192). Additionally, a Multi Quantum Wells (MQW) layer (194) is formed between the n-type semiconductor layer (193) and the p-type semiconductor layer (192).

[0104] The transparent substrate (195) can serve as the base of a pn junction capable of emitting light. The transparent substrate (195) may include, for example, sapphire (Al2O3) with a crystal structure similar to that of the semiconductor layers (193, 192).

[0105] A pn junction can be realized by joining an n-type semiconductor layer (193) and a p-type semiconductor layer (192). A depletion region can be formed between the n-type semiconductor layer (193) and the p-type semiconductor layer (192). In the depletion region, electrons from the n-type semiconductor layer (193) and holes from the p-type semiconductor layer (192) can recombine. Light can be emitted by the recombination of electrons and holes.

[0106] The n-type semiconductor layer (193) may include, for example, n-type gallium nitride (n-type GaN). Additionally, the p-type semiconductor layer (192) may also include, for example, p-type gallium nitride (p-type GaN). The energy band gap of gallium nitride (GaN) is 3.4 eV (electronvolt), which can emit light of a wavelength shorter than approximately 400 nm. Thus, deep blue or ultraviolet light may be emitted at the junction of the n-type semiconductor layer (193) and the p-type semiconductor layer (192).

[0107] The n-type semiconductor layer (193) and the p-type semiconductor layer (192) are not limited to gallium nitride, and various semiconductor materials may be used depending on the required light.

[0108] The first electrode (191a) of the light-emitting diode (190) is electrically in contact with a p-type semiconductor layer (192), and the second electrode (191b) is electrically in contact with an n-type semiconductor layer (193). The first electrode (191a) and the second electrode (191b) can function not only as electrodes but also as reflectors that reflect light.

[0109] When a voltage is applied to the light-emitting diode (190), holes can be supplied to the p-type semiconductor layer (192) through the first electrode (191a), and electrons can be supplied to the n-type semiconductor layer (193) through the second electrode (191b). Electrons and holes can recombine in the depletion layer formed between the p-type semiconductor layer (192) and the n-type semiconductor layer (193). At this time, while the electrons and holes are recombining, the energy of the electrons and holes (e.g., kinetic energy and potential energy) can be converted into light energy. In other words, when electrons and holes recombine, light can be emitted.

[0110] At this time, the energy band gap of the quantum well layer (194) is smaller than the energy band gap of the p-type semiconductor layer (192) and / or the n-type semiconductor layer (193). As a result, holes and electrons can be captured in the quantum well layer (194), respectively.

[0111] Holes and electrons trapped in the quantum well layer (194) can easily recombine with each other in the quantum well layer (194). As a result, the light generation efficiency of the light-emitting diode (190) can be improved.

[0112] In the quantum well layer (194), light having a wavelength corresponding to the energy gap of the quantum well layer (194) may be emitted. For example, in the quantum well layer (194), blue light between 420 nm and 480 nm may be emitted. Thus, the quantum well layer (194) may correspond to a light-emitting layer that emits blue light.

[0113] The light generated by the recombination of electrons and holes is not emitted in a specific direction, and as shown in FIG. 6, the light can be emitted in all directions. However, in the case of light emitted from a surface such as a quantum well layer (194), the intensity of the light emitted in a direction perpendicular to the light-emitting surface is the greatest, and the intensity of the light emitted in a direction parallel to the light-emitting surface is the smallest.

[0114] A first reflective layer (196) is provided on the outer side of the transparent substrate (195) (the upper side of the transparent substrate in the drawing). That is, the first reflective layer (196) can be placed on the upper side of the light-emitting layer (194). In addition, a second reflective layer (197) is provided on the outer side of the p-type semiconductor layer (192) (the lower side of the p-type semiconductor layer in the drawing). In this way, the transparent substrate (195), the n-type semiconductor layer (193), the quantum well layer (194), and the p-type semiconductor layer (192) can be placed between the first reflective layer (196) and the second reflective layer (197).

[0115] The first reflective layer (196) and the second reflective layer (197) can each reflect some of the incident light and allow other of the incident light to pass through.

[0116] For example, the first reflective layer (196) and the second reflective layer (197) can reflect light having a wavelength included in a specific wavelength range and pass light having a wavelength outside the specific wavelength range. For example, the first reflective layer (196) and the second reflective layer (197) can reflect blue light having a wavelength between 420 nm and 480 nm emitted from the quantum well layer (194).

[0117] Additionally, the first reflective layer (196) and the second reflective layer (197) can reflect incident light having a specific angle of incidence and allow light outside the specific angle of incidence to pass through. As such, the first reflective layer (196) and the second reflective layer (197) may be a Distributed Bragg Reflector (DBR) layer formed by stacking materials with different refractive indices to have various reflectances depending on the angle of incidence.

[0118] For example, the first reflective layer (196) can reflect light incident at a small angle of incidence and pass light incident at a large angle of incidence. Additionally, the second reflective layer (197) can reflect or pass light incident at a small angle of incidence and reflect light incident at a large angle of incidence. Here, the incident light may be blue light having a wavelength between 420 nm and 480 nm.

[0119] FIG. 7 illustrates an example of a cross-section according to AA of FIG. 6.

[0120] Referring to FIG. 7, blue light emitted from a light-emitting diode (190) can be partially converted into red light and green light as it passes through a quantum dot cover (160). However, even after the blue light emitted from the light-emitting diode (190) passes through the quantum dot cover (160), the intensity of the blue light is still greater than that of the converted red light and green light. In this case, because the light intensities of the blue light, red light, and green light are different, it is difficult for the light that has passed through the quantum dot cover (160) to become white light.

[0121] Conventionally, when using quantum dot resin to obtain white light from monochromatic light emitted from a light-emitting diode, the amount used was relatively large. This was because a large amount of quantum dot resin was required to form the quantum dot layer, as the thickness of the quantum dot layer had to be sufficiently secured.

[0122] According to one embodiment, some of the light emitted outside the quantum dot cover (160) after passing through the quantum dot cover (160) is reflected backward by the reflective layer (180), and the light reflected backward can be reflected forward again by the lower reflective layer (113). In other words, the light emitted from the light-emitting diode (190) can be regenerated by the reflective layer (180) and the lower reflective layer (113). Through the regeneration process described above, the light emitted from the light-emitting diode (190) can pass through the quantum dot cover (160) multiple times. As the light passes through the quantum dot cover (160) multiple times, the intensity of the blue light is relatively reduced, and the intensity of the red light and green light can be increased. Through this, the difference in intensity between the blue light, red light, and green light can be reduced. By reducing the difference in intensity between the blue light, red light, and green light, the desired white light can be obtained. In addition, since a quantum dot cover (160) is formed by dispensing a liquid quantum dot resin in a minimum area to cap the light-emitting diode (190), the amount of quantum dot resin used can be drastically reduced compared to conventional methods.

[0123] According to one embodiment, the lower surface (181) of the reflective layer (180) may be provided to have a convex shape facing upward. The reflective layer (180) may be formed by dispensing a liquid reflective material onto a refraction cover (170) and then curing it. The liquid reflective material may include, for example, silicon dioxide (SiO2) or silver (Ag).

[0124] According to one embodiment, so that the lower surface (181) of the reflective layer (180) may have an upwardly convex shape, the recess provided in the center of the refraction cover (170) may have a central part that is upwardly convex. That is, the recess may be recessed toward the substrate (112) from a point (P) having a maximum height (h) in the refraction cover (170), and the central part of the recess may be provided in an upwardly convex shape. The upper surface of the reflective layer (180) may be provided flat. That is, the upper surface of the reflective layer (180) may be provided as a circular plane.

[0125] The straight distance between the center of the lower surface (181) of the reflective layer (180) and the center of the upper surface of the quantum dot cover (160) can be set to d1. As described below, the light emission directional angle profile of the light source (111) can be changed by varying the distance between the center of the lower surface (181) of the reflective layer (180) and the center of the upper surface of the quantum dot cover (160). More specifically, if the distance between the lower surface (181) of the reflective layer (180) and the upper surface of the quantum dot cover (160) is shortened, the light emission directional angle of the light source (111) can be increased. Conversely, if the distance between the lower surface (181) of the reflective layer (180) and the upper surface of the quantum dot cover (160) is increased, the light emission directional angle of the light source (111) can be decreased.

[0126] In the following, the radius of the lower surface of the quantum dot cover (160) is denoted as Lq. The horizontal distance from the center of the light-emitting diode (190) to the outermost point of the reflection layer (180) where the marginal ray passing through the refraction cover (170) comes into contact is denoted as Lr. The vertical distance between the reflection layer (180) where the marginal ray comes into contact and the lower reflection layer (113) is denoted as H1. The radius of the lower surface of the refraction cover (170) is denoted as Ls. Additionally, the angle between the marginal ray and the lower reflection layer (113) is denoted as θm1. θm1 can be expressed differently as follows.

[0127] θm1 = tan -1(H1 / Lr)

[0128] According to one embodiment, a refractive cover (170) and a reflective layer (180) may be formed to satisfy 10˚ < θm1 < 70˚. A light source (111) may be provided with 10˚ < θm1 < 70˚ so as to obtain a light profile of a high directional angle.

[0129] Additionally, Lr can be made larger than Lq so that light emitted upward from the quantum dot cover (160) can be reflected by the reflection layer (180). That is, it can be made to satisfy Lr > Lq. With this structure, light emitted from the quantum dot cover (160) at an angle higher than θm1 can be reflected backward by the reflection layer (180), and the light reflected by the reflection layer (180) can be re-reflected forward by the lower reflection layer (113).

[0130] Additionally, the diameter of the lower surface (181) of the reflective layer (180) may be larger than the diameter of the lower surface of the quantum dot cover (160). With this structure, the reflective layer (180) can reflect light emitted upward from its lower surface toward the quantum dot cover (160) toward the rear.

[0131] FIG. 8 illustrates an example of a light profile emitted from a light source according to one embodiment.

[0132] Referring to FIG. 8, a light source (111) according to one embodiment may have a light profile approximately shaped like a bat wing. Alternatively, the light source (111) may have a light profile with a high directional angle. Since a reflective layer (180) is provided on the upper side of the light-emitting diode (190) and the quantum dot cover (160), light emitted upward from the light-emitting diode (190) is reflected downward by the reflective layer (180), and the light reflected downward undergoes a process of being re-reflected by the lower reflective layer (113), thereby allowing the light to be emitted to the outside of the refractive cover (170). By undergoing the above process, the light emitted to the outside of the refractive cover (170) may have a light profile with a high directional angle.

[0133] The light source (190) may have a light profile that is approximately bat wing shaped. Here, the bat wing shaped light profile may exhibit a light profile in which the intensity of light emitted in an oblique direction (e.g., a direction having an angle interval of approximately 30 to 70 degrees (peak 1 / 2 point) from the vertical axis perpendicular to the substrate (112)) is greater than the intensity of light emitted from the light source (111) in a direction perpendicular to the substrate (112).

[0134] The light profile shown in FIG. 8 is an example of a light profile of a light source (111), and according to various embodiments, the light profile of the light source (111) may have a light profile similar to FIG. 8.

[0135] Due to the light source (111) having a bat-wing shaped light profile, the number of light-emitting diodes (190) included in the display device (10) can be reduced.

[0136] In order to improve the image quality of the display device (10), it is important for the backlight unit (100) to emit surface light with uniform brightness. For example, if the number of point light sources (light-emitting diodes) is reduced, the difference between the brightness in the area where the light-emitting diodes are located and the brightness in the area where the light-emitting diodes are not located (the area between the light-emitting diodes) may increase. In other words, if the number of point light sources (light-emitting diodes) is reduced, the uniformity of brightness of the surface light emitted by the backlight unit (100) may deteriorate.

[0137] At this time, when a light source (111) having a bat-wing shaped light profile is used, the difference in brightness between the region where each light source (111) is located and the region between two adjacent light sources can be reduced. As a result, the number of light-emitting diodes (190) can be reduced.

[0138] Furthermore, when the thickness of the display device (10) is reduced, the optical distance (OD) for light emitted from a point light source light-emitting diode to spread into surface light is shortened. As a result, the uniformity of brightness of the surface light emitted by the backlight unit (100) may deteriorate. To maintain brightness uniformity, the number of light-emitting diodes may be increased.

[0139] By including a light-emitting diode (190), a quantum dot cover (160), a refractive cover (170), and a reflective layer (180), the light source (111) can have a bat-wing shaped light profile, and by having a bat-wing shaped light profile, the increase in the number of light sources (111) can be minimized.

[0140] FIG. 9 illustrates the emission spectrum according to the presence or absence of a reflective layer in a light source of a backlight unit according to one embodiment.

[0141] Referring to FIG. 9, a light source (111) according to one embodiment may have different characteristics of the emission spectrum by including a reflective layer.

[0142] Specifically, when the reflective layer (180) is not included, the intensity of the blue light emitted from the light source is relatively greater than the intensity of the green light and red light. Since the intensity of the blue light is greater than the intensity of the green light, and the intensity of the green light is greater than the intensity of the red light, the imbalance between the blue light, green light, and red light is relatively large. Due to this imbalance, the light source may not be able to emit white light. To overcome the imbalance, a relatively large amount of quantum dot resin is required.

[0143] A light source (111) according to one embodiment includes a reflective layer (180) so that blue light, green light, and red light can be balanced. In particular, the intensity of blue light and green light can be similar. In addition, the difference in intensity between blue light and red light can be reduced, and likewise, the difference in intensity between green light and red light can be reduced. As such, by reducing the difference in intensity between blue light, green light, and red light, the light source (111) can emit white light with only a relatively small amount of quantum dot resin. That is, the amount of expensive quantum dot resin used can be minimized. Through this, the production cost of the light source (111) can be reduced, and furthermore, the production cost of the display device (10) can be reduced.

[0144] FIG. 10 illustrates another example of a cross-section according to AA of FIG. 5.

[0145] Referring to FIG. 10, in one embodiment, the light source (111) may be provided with a distance d2 between the center of the lower surface (181) of the reflective layer (180) and the center of the upper surface of the quantum dot cover (160). d2 may be provided to be smaller than d1 shown in FIG. 7. That is, it may be provided to satisfy d2 < d1. The vertical distance H2 between the reflective layer (180) and the lower reflective layer (113) to which the ambient light contacts may be provided to be smaller than H1. That is, it may be provided to satisfy H2 < H1.

[0146] As illustrated in FIG. 10, when the distance between the reflective layer (180) and the quantum dot cover (160) is shortened, the angle θm2 between the reflective layer (113) and the marginal ray passing through the refractive cover (170) from the center of the light-emitting diode (190) can be reduced. That is, if d2 < d1, then θm2 < θm1. When θm2 is reduced, the directional angle of the light source (111) can be larger than when θm1. In other words, when the distance between the reflective layer (180) and the quantum dot cover (160) is shortened, a light profile with a relatively high directional angle can be obtained.

[0147] On the other hand, even if d2 becomes smaller than d1, it can be arranged to satisfy 10˚ < θm2 < 70˚. That is, 10˚ < tan -1 (H2 / Lr) < 70˚ can be satisfied.

[0148] In this way, the directional angle of the light source (111) can be adjusted by adjusting the distance between the lower surface (181) of the reflective layer (180) and the quantum dot cover (160).

[0149] FIG. 11 illustrates another example of a cross-section according to AA of FIG. 5. FIG. 12 illustrates the light path on the underside of the reflective layer shown in FIG. 11.

[0150] Referring to FIGS. 11 and 12, in one embodiment, a light source (111) may have a glass bead array (282) provided on the lower surface (281) of a reflective layer (280). The lower surface (281) of the reflective layer (280) may be provided flat. The lower surface (281) of the reflective layer (280) may be provided as a circular plane. The central portion of the refractive cover (270) may be recessed to correspond to the reflective layer (280). The vertical distance between the reflective layer (280) and the lower reflective layer (113) to which the ambient light contacts may be H. H > H1. According to one embodiment, 10˚ < tan -1It can be arranged to satisfy (H / Lr) < 70˚. That is, it can satisfy 10˚ < θm < 70˚.

[0151] Referring to FIG. 11, the diameter of the lower surface (281) of the reflective layer (280) can be made larger than the diameter of the lower surface of the quantum dot cover (160). With this structure, the reflective layer (280) can reflect light emitted upward from its lower surface toward the quantum dot cover (160) toward the rear.

[0152] Referring to FIG. 12, a light source (111) according to one embodiment may include a glass bead array (282), which is a retro-reflector, on the lower surface (281) of a reflective layer (280). Depending on the characteristics of the retro-reflector, light incident on the glass bead array (282) may be reflected at an angle of exit equal to the angle of incidence. By including a glass bead array (282) on the lower surface of the reflective layer (280), the light source (111) according to one embodiment may reflect light incident from the light-emitting diode (190) through the quantum dot cover (160) to the reflective layer (280) to the lower reflective layer (113). As described above, the light reflected to the lower reflective layer (113) is re-reflected forward by the lower reflective layer (113), so that the light source (111) can obtain a light profile with a high directional angle.

[0153] FIG. 13 illustrates another example of a cross-section according to AA of FIG. 5. FIG. 14 illustrates a microprism array provided on the lower surface of the reflective layer illustrated in FIG. 13. FIG. 15 schematically illustrates the light path on the lower surface of the reflective layer illustrated in FIG. 13.

[0154] Referring to FIGS. 13 and 14, a light source (111) according to one embodiment may have a microprism array (381) provided on the lower surface of a reflective layer (380). The lower surface of the reflective layer (380) may be provided flat. The lower surface of the reflective layer (380) may be provided as a circular plane. The refractive cover (370) may have a central portion recessed to correspond to the reflective layer (380). The vertical distance between the reflective layer (380) and the lower reflective layer (113) to which the ambient light contacts may be H. H may be greater than H1. As shown in FIG. 14, the microprism array (381) may include a tetrahedral array.

[0155] Referring to FIG. 13, the diameter of the lower surface (381) of the reflective layer (380) can be made larger than the diameter of the lower surface of the quantum dot cover (160). With this structure, the reflective layer (380) can reflect light emitted upward from its lower surface toward the quantum dot cover (160) toward the rear.

[0156] Referring to FIGS. 14 and 15, a light source (111) according to one embodiment may include a microprism array (381), which is a retro-reflector, on the lower surface of a reflective layer (380). Depending on the characteristics of the retro-reflector, light incident on the microprism array (381) may be reflected at an angle of exit equal to the angle of incidence. By including a microprism array (381) on the lower surface of the reflective layer (380), the light source (111) according to one embodiment may reflect light incident from a light-emitting diode (190) through a quantum dot cover (160) to the reflective layer (380) to the lower reflective layer (113). As described above, the light reflected to the lower reflective layer (113) is re-reflected forward by the lower reflective layer (113), so that the light source (111) can obtain a light profile with a high directional angle.

[0157] FIG. 16 schematically illustrates an example of a method for manufacturing a light source of a backlight unit according to one embodiment.

[0158] Hereinafter, an example of a method for manufacturing a backlight unit according to one embodiment will be described with reference to FIG. 16.

[0159] Referring to FIG. 16, a light source (111) according to one embodiment can be manufactured using an injection molding process.

[0160] Specifically, an upper mold (B2) may be placed on a quantum dot cover (160) that is dispensed and cured to cover the light-emitting diode (190) and a light-emitting diode (190) mounted on a substrate (112) in a COB (Chip On Board) manner, and a lower mold (B1) may be placed below the substrate (112).

[0161] The upper mold (B2) may include a predetermined groove (r) that determines the shape of the refraction cover (170). The predetermined groove (r) may be provided to correspond to the positions of the light-emitting diode (190) and the quantum dot cover (160).

[0162] According to one embodiment, a substrate (112), a light-emitting diode (190), and a quantum dot cover (160) are positioned on a lower mold (B1), and an upper mold (B2) is moved toward the lower mold to close the cavity, after which a transparent liquid material forming a refraction cover (170) can be injected through a channel (p1) connected to the groove (r). The transparent material injected into the groove (r) through the channel (p1) can be cured to form a refraction cover (170). Through this process, a refraction cover (170) can be formed on the substrate (112) to cover the quantum dot cover (160) immediately without a process of bonding the refraction cover (170) onto the substrate (112).

[0163] According to one embodiment, a reflective layer (180) can be formed by forming a refraction cover (170) on a substrate (112) without a bonding process through the injection molding process described above, dispensing a liquid reflective material onto the refraction cover (170), and then curing it. The liquid reflective material may include, for example, silicon dioxide (SiO2) or silver (Ag). Alternatively, the reflective layer may be formed by a double injection molding process together with the refraction cover.

[0164] FIG. 17 schematically illustrates another example of a method for manufacturing a light source of a backlight unit according to one embodiment.

[0165] Referring to FIG. 17, a light source (111) can be manufactured by mounting a light-emitting diode (190) on a substrate (112) in a COB (Chip On Board) manner, then dispensing and curing a liquid quantum dot resin to form a refractive cover (170), and bonding a separately manufactured refractive cover (170) and a reflective layer (180) onto the substrate (112).

[0166] That is, a light source (111) can be produced by separately manufacturing a plurality of refractive covers (170) and reflective layers (180), and then bonding them onto a substrate (112) so that they correspond to a plurality of light-emitting diodes (190) and quantum dot covers (160).

[0167] The refraction cover (170) and the reflective layer (180) can be manufactured in various ways. For example, they can be manufactured in a single process using a double injection molding method, or they can be manufactured by first producing the refraction cover through injection molding and then dispensing and curing the liquid reflective material.

[0168] FIG. 18 schematically illustrates a method of forming a quantum dot cover in a method of manufacturing a light source of a backlight unit according to one embodiment. FIG. 19 schematically illustrates a method of forming a refractive cover in a method of manufacturing a light source of a backlight unit according to one embodiment. FIG. 20 schematically illustrates a method of forming a reflective layer in a method of manufacturing a light source of a backlight unit according to one embodiment.

[0169] A method for manufacturing a light source (111) according to one embodiment will be described with reference to FIGS. 18 to 20.

[0170] Referring to FIG. 18, after mounting a light-emitting diode (190) on a substrate (112) using a COB (Chip On Board) method, a liquid quantum dot resin (T1) can be dispensed through a first dispenser (J1) to cover the light-emitting diode (190). The first dispenser (J1) is positioned above the light-emitting diode (190) so that the quantum dot resin (T1) can be dispensed onto the light-emitting diode (190). After the quantum dot resin (T1) is dispensed in a liquid state, it can be cured to form a quantum dot cover (160).

[0171] Referring to FIG. 19, the second dispenser (J2) and a plurality of third dispensers (J3) can each dispense a transparent liquid substance (T2). The second dispenser (J2) and the third dispensers (J3) may be spaced apart by a predetermined distance in the horizontal direction. The second dispenser (J2) may be located between the plurality of third dispensers (J3).

[0172] The second dispenser (J2) and the plurality of third dispensers (J3) can each dispense a transparent material (T2) in a liquid state, and the transparent material dispensed in a liquid state by the second dispenser (J2) and the plurality of third dispensers (J3) can form a refraction cover (170) by hardening.

[0173] The shape of the refraction cover (170) can be determined according to the amount of transparent material dispensed from each of the second dispenser (J2) and the plurality of third dispensers (J3), the distance between the second dispenser (J2) and the plurality of third dispensers (J3), and the thixotropic properties of the transparent material (T2).

[0174] Referring to FIG. 20, a fourth dispenser (J4) can form a liquid reflective material (T3) by dispensing it into a recess formed in the center of the refraction cover (170) and then curing it to form a reflective layer (180).

[0175] As shown in FIGS. 18 to 20, a quantum dot cover (160), a refraction cover (170), and a reflection layer (180) can be formed on a substrate (112) using only dispensing or jetting methods, rather than injection molding.

[0176] Specific embodiments have been illustrated and described above. However, the invention is not limited to the embodiments described above, and those skilled in the art may make various modifications without departing from the essence of the technical concept of the invention as described in the following claims. Explanation of the symbols

[0177] 10 : Display device 20 : LCD panel 100 : Backlight unit 110 : Light source module 111 : Light source 112 : Substrate 113 : Lower reflection layer 130 : Diffusion plate 140 : Optical sheet 160 : Quantum Dot Cover 170, 270, 370: Refraction cover 180, 280, 380: Reflection layer 190 : Light Emitting Diode

Claims

Claim 1 A display device comprising: a liquid crystal panel; and a backlight unit that provides light to the liquid crystal panel; wherein the backlight unit comprises: a substrate; a light-emitting diode mounted on the substrate; a quantum dot cover provided to cover the light-emitting diode and convert the wavelength of light emitted from the light-emitting diode; a refractive cover covering the light-emitting diode and the quantum dot cover, wherein a recess is provided in the center of the upper surface and is recessed toward the quantum dot cover; and a reflective layer disposed on the upper side of the quantum dot cover by being provided in the recess, and having a lower surface diameter smaller than the upper surface diameter; wherein the lower surface of the reflective layer and the center of the recess are provided in a convex shape toward the upper side. Claim 2 In claim 1, the display device wherein the refraction cover is provided to have a maximum height at a point spaced a predetermined distance in the horizontal direction from the center of the light-emitting diode. Claim 3 In paragraph 2, the display device is configured such that the refraction cover has a shape that is convex upward at the maximum height. Claim 4 In paragraph 2, the above-mentioned refraction cover is a display device having a rotationally symmetrical shape. Claim 5 delete Claim 6 A display device according to claim 1, wherein the diameter of the lower surface of the reflective layer is larger than the diameter of the lower surface of the quantum dot cover. Claim 7 A display device according to claim 1, wherein the lower surface of the reflective layer is provided as a flat surface, and a glass bead array or a microprism array is provided on the lower surface of the reflective layer. Claim 8 In claim 1, the backlight unit further comprises a lower reflective layer formed by applying PSR (Photo Solder Resist) on the substrate. Claim 9 In claim 8, let Lr be the horizontal distance from the center of the light-emitting diode to the outermost point of the reflective layer where the marginal ray passing through the refraction cover contacts, and let H be the vertical distance between the outermost point of the reflective layer and the lower reflective layer, then 10˚ < tan -1 A display device with (H / Lr) < 70˚. Claim 10 In claim 1, the light-emitting diode is a display device mounted on the substrate in a Chip On Board (COB) manner. Claim 11 In claim 1, the light-emitting diode is a display device configured to emit blue light. Claim 12 In claim 11, the quantum dot cover is a display device configured to convert a portion of the blue light emitted from the light-emitting diode into red light and green light. Claim 13 In claim 1, the quantum dot cover is a display device formed by dispensing and curing a liquid quantum dot resin. Claim 14 In claim 1, the refraction cover is a display device formed by dispensing and curing a transparent material in a liquid state. Claim 15 In claim 1, the reflective layer is a display device formed by dispensing and curing a liquid reflective material.

Images