Method for manufacturing light emitting diode module and system for the same

Abstract

A display device may include a liquid crystal panel; a substrate; and a plurality of light-emitting diodes provided on one side of the substrate and emitting light toward the liquid crystal panel. Each of the plurality of light-emitting diodes may include a first reflective layer; a second reflective layer; and a light-emitting layer disposed between the first reflective layer and the second reflective layer. The second reflective layer may be disposed between the substrate and the light-emitting layer. The reflectance of the first reflective layer for a first light incident at a first angle of incidence may be different from the reflectance of the second reflective layer for the first light incident at the first angle of incidence.

Description

Technology Field

[0001] The disclosed invention relates to a method for manufacturing a light-emitting diode module having a plurality of light-emitting diodes arranged therein and a manufacturing system. Background Technology

[0002] A display device is a type of output device that visually displays data information and images, such as characters or shapes, and may include televisions, various monitors, and various portable terminals (e.g., laptops, tablet PCs, and smartphones).

[0003] Display devices can be classified into self-emissive display devices that use display panels that emit light themselves, such as organic light-emitting diodes (OLEDs), and non-emissive display devices that use display panels that must receive light from a backlight unit, such as liquid crystal displays (LCDs).

[0004] Backlight units can be classified into direct type, in which the light source is placed at the rear of the display panel, and edge type, in which the light source is placed at the side of the display panel, depending on the position of the light source.

[0005] A direct-type backlight unit may include a light source module in which a plurality of light-emitting diodes are mounted on a printed circuit board. The problem to be solved

[0006] One aspect of the disclosed invention provides a method and system for manufacturing a light-emitting diode module having a plurality of light-emitting diodes mounted thereon, wherein a protective material sprayed onto a light-emitting diode chip is cured through a reflow process, thereby simplifying the manufacturing process, shortening the curing time, and ensuring uniformity of curing. means of solving the problem

[0007] A method for manufacturing a light-emitting diode module according to one embodiment comprises: a step of mounting a light-emitting diode chip on the surface of a substrate; a step of spraying a protective material onto the light-emitting diode chip mounted on the surface of the substrate; and a step of curing the protective material sprayed onto the light-emitting diode chip by a second reflow process; wherein the step of mounting a plurality of light-emitting diode chips comprises: a step of forming solder on a pad formed on the surface of the substrate; a step of placing the light-emitting diode chip on the formed solder; and a step of curing the solder by a first reflow process.

[0008] The step of mounting the plurality of light-emitting diode chips comprises: forming solder on a pad formed on the surface of the substrate; and placing the light-emitting diode chips on the formed solder.

[0009] The step of mounting the plurality of light-emitting diode chips may include the step of curing the solder by a first reflow process.

[0010] The step of curing the protective material can be performed by using the reflow device used to cure the solder to carry out the first reflow process.

[0011] The step of curing the protective material may further include the step of transferring the substrate, on which the protective material has been sprayed onto the light-emitting diode chip, to the reflow device by means of a conveyor belt from the spraying device that sprays the protective material.

[0012] The above protective material may include a thermosetting transparent resin.

[0013] The step of spraying the protective material may include spraying the protective material so that it surrounds the light-emitting diode chip.

[0014] The method includes the step of forming an optical dome surrounding a light-emitting diode chip mounted on the surface of the substrate, wherein the step of forming the optical dome may include the step of spraying the protective material; and the step of curing the protective material.

[0015] The optical dome can disperse light emitted from the light-emitting diode chip.

[0016] The light-emitting diode chip may include a flip-chip light-emitting diode; and a reflector disposed on the light-emitting surface of the flip-chip light-emitting diode.

[0017] The step of curing the protective material may include heating the protective material to a temperature in the range of 160 to 200°C by the second reflow process.

[0018] The step of curing the solder may include heating the solder to a temperature in the range of 230 to 270°C by the first reflow process.

[0019] The above substrate may include at least one of a planar substrate and a bar-type substrate.

[0020] A manufacturing system for a light-emitting diode module according to one embodiment includes: a surface mounting device for mounting a light-emitting diode chip on the surface of a substrate; and a spraying device for spraying a protective material onto the light-emitting diode chip mounted on the surface of the substrate; wherein the surface mounting device includes: a printing device for forming solder on a pad formed on the surface of the substrate; a mounting device for placing the light-emitting diode chip on the formed solder; and a reflow device for curing the solder by a first reflow process; and wherein the reflow device cures the protective material sprayed onto the light-emitting diode chip by a second reflow process.

[0021] The above protective material may include a thermosetting transparent resin.

[0022] The above spraying device can spray so that the protective material surrounds the light-emitting diode chip.

[0023] The above reflow device can form an optical dome by curing a protective material sprayed onto the light-emitting diode chip.

[0024] The optical dome can disperse light emitted from the light-emitting diode chip. Effects of the invention

[0025] According to one aspect of the disclosed invention, in manufacturing a light-emitting diode module having a plurality of light-emitting diodes mounted thereon, by curing a protective material sprayed onto a light-emitting diode chip through a reflow process, the manufacturing process can be simplified, the curing time can be shortened, and the uniformity of the curing can be ensured. Brief explanation of the drawing

[0026] FIG. 1 is a perspective view illustrating an example of the external appearance of a display device. Figure 2 is an exploded perspective view showing an example of the structure of a display device. FIG. 3 is a side cross-sectional view showing an example of a liquid crystal panel included in a display device. Figures 4 and 5 are exploded perspective views of a backlight unit. FIG. 6 is a perspective view showing the structure of a light source included in a light source module of a display device. FIG. 7 is a side cross-sectional view showing the structure of a light source included in a light source module of a display device. Figure 8 is a side cross-sectional view showing the structure of a light-emitting diode chip. FIG. 9 is a flowchart relating to a method for manufacturing a light-emitting diode module according to one embodiment. FIG. 10 is a block diagram showing the configuration of a manufacturing system for manufacturing a light-emitting diode module according to one embodiment. FIG. 11 is a flowchart illustrating the mounting process of a light-emitting diode chip in a method for manufacturing a light-emitting diode module according to one embodiment. FIG. 12 is a block diagram illustrating a surface mount device of a manufacturing system for a light-emitting diode module according to one embodiment. FIG. 13 is a graph showing an example of a temperature profile applied to a second reflow process in a method for manufacturing a light-emitting diode module according to one embodiment. Specific details for implementing the invention

[0027] Throughout the specification, the same reference numerals refer to the same components. This specification does not describe all elements of the embodiments, and general content in the art to which the invention pertains or content that overlaps between embodiments is omitted. The terms 'part, module, component, block' used in the specification may be implemented in software or hardware, and depending on the embodiments, a plurality of 'parts, modules, components, blocks' may be implemented as a single component, or a single 'part, module, component, block' may include a plurality of components.

[0028] Throughout the specification, when a part is described as being "connected" to another part, this includes not only cases where they are directly connected but also cases where they are indirectly connected, and indirect connections include connections made via a wireless communication network.

[0029] Furthermore, when it is stated that a part "includes" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0030] Throughout the specification, when it is stated that a component is located "on" another component, this includes not only cases where a component is in contact with another component, but also cases where another component exists between the two components.

[0031] The terms first, second, etc. are used to distinguish one component from another, and the components are not limited by the aforementioned terms.

[0032] Singular expressions include plural expressions unless there is an obvious exception in the context.

[0033] In each step, identification codes are used for convenience of explanation and do not describe the order of the steps; the steps may be performed differently from the specified order unless a specific order is clearly indicated in the context.

[0034] Embodiments of the present invention will be described in detail below with reference to the attached drawings. A light-emitting diode module manufactured by the manufacturing method and manufacturing system of the present invention can be used in various devices requiring a light source. For example, the light-emitting diode module can be used in a display device; therefore, a display device in which the light-emitting diode module can be used will first be described.

[0035] FIG. 1 is a perspective view illustrating an example of the external appearance of a display device.

[0036] A 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 a television (TV), but is not limited thereto.

[0037] For example, the display device (10) can be implemented in various forms other than a TV, such as a monitor, a portable multimedia device, or a portable communication device. Any device that visually displays images can be the display device (10), and there are no restrictions on the type thereof.

[0038] 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 outdoor area is not necessarily limited to an open space, and the display device (10) may be installed in any indoor location where many people can enter and exit, such as a subway station, shopping mall, movie theater, company, or store.

[0039] 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.

[0040] As illustrated in FIG. 1, the display device (10) may include a main body (11) and a screen (12) that displays an image (I).

[0041] The main body (11) forms the exterior of the display device (10), and the interior of the main body (11) may be provided with components for the display device (10) to display an image (I) or perform various functions. 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 have a curved shape.

[0042] 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.

[0043] The screen (12) may include, for example, a self-emissive panel capable of emitting light directly (e.g., a light-emitting diode panel or an organic light-emitting diode panel) or a non-emissive panel capable of passing through or blocking light emitted by a light source device (e.g., a backlight unit) or the like (e.g., a liquid crystal panel).

[0044] A plurality of pixels (P) are formed on the screen (12), and an image (I) displayed on the screen (12) can be realized by light emitted by each of the plurality of pixels (P). For example, the light emitted by each of the plurality of pixels (P) can be combined to form an image (I) on the screen (12).

[0045] 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) consists of subpixels (P R , P G , P B It may include ).

[0046] Subpixels (P R , P G , P B ) is a red subpixel (P) capable of emitting red light. R ) and a green subpixel (P) capable of emitting green light G ) and a blue subpixel (P) capable of emitting blue light B It may include ).

[0047] For example, red light can represent light with wavelengths ranging from approximately 620 nm to 750 nm. Green light can represent light with wavelengths ranging from approximately 495 nm to 570 nm. Blue light can represent light with wavelengths ranging from approximately 450 nm to 495 nm.

[0048] 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).

[0049] FIG. 2 is an exploded perspective view showing an example of the structure of a display device, and FIG. 3 is a side cross-sectional view showing an example of a liquid crystal panel included in the display device. The display device (10) described in the example is a non-emissive display device including a liquid crystal panel and a backlight unit.

[0050] As shown in FIG. 2, various components for generating an image (I) displayed on a screen (12) may be provided inside the main body (11).

[0051] For example, the main body (11) may be provided with a backlight unit (100) which is a surface light source, a liquid crystal panel (20) which blocks or passes light emitted from the backlight unit (100), a control assembly (50) which controls the operation of the backlight unit (100) and the liquid crystal panel (20), and a power assembly (60) which supplies power to the backlight unit (100) and the liquid crystal panel (20).

[0052] The main body (11) may include a bezel (13) for supporting a liquid crystal panel (20), a backlight unit (100), a control assembly (50), and a power assembly (60), a frame middle mold (14), a bottom chassis (15), and a rear cover (16).

[0053] The backlight unit (100) may include a point light source that emits monochromatic light or white light. Additionally, the backlight unit (100) may refract, reflect, and scatter light to convert the light emitted from the point light source into uniform surface light. In this way, the backlight unit (100) may emit uniform surface light toward the front by refracting, reflecting, and scattering the light emitted from the point light source. The backlight unit (100) is described in more detail below.

[0054] A liquid crystal panel (20) is provided in front of a backlight unit (100) and can block or allow light emitted from the backlight unit (100) to form an image (I).

[0055] The front surface of the liquid crystal panel (20) forms the screen (12) of the display device (10) described above, and the liquid crystal panel (20) can form a plurality of pixels (P). Each of the plurality of pixels (P) of the liquid crystal panel (20) can independently block or pass light from the backlight unit (100), and the light passed by the plurality of pixels (P) can form an image (I) displayed on the screen (12). The plurality of pixels (P) can be arranged in a matrix form.

[0056] Referring to 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).

[0057] 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.

[0058] A first polarizing film (21) and a second polarizing film (29) are provided on the outer side of a first transparent substrate (22) and a second transparent substrate (28). The first polarizing film (21) and the second polarizing film (29) can each allow specific polarization to pass through and block other polarization. For example, the first polarizing film (21) can allow polarization of a first direction to pass through and block other polarization. Additionally, the second polarizing film (29) can allow polarization of a second direction to pass through and block other polarization. At this time, the first direction and the second direction may be orthogonal to each other. Consequently, polarization that has passed through the first polarizing film (21) cannot pass through the second polarizing film (29).

[0059] A color filter (27) may be provided on the inner side of the second transparent substrate (28). The color filter (27) may include a red filter (27R) that passes red light, a green filter (27G) that passes green light, and a blue filter (27G) that passes blue light. The red filter (27R), the green filter (27G), and the blue filter (27B) may be arranged side by side with each other. The area where the color filter (27) is formed may correspond to the pixel (P) described above. The area where the red filter (27R) is formed corresponds to a red subpixel (P R Corresponding to ), and the area where the green filter (27G) is formed is the green subpixel (P G Corresponding to ), the area where the blue filter (27B) is formed is a blue subpixel (P B It can respond to ).

[0060] 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 formed 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).

[0061] A thin film transistor (TFT) (24) may be provided on the inner side of the second transparent substrate (22). The thin film transistor (24) may pass or block current flowing through the pixel electrode (23). For example, depending on the turn-on (closed) or turn-off (open) of the thin film transistor (24), an electric field may be formed or removed between the pixel electrode (23) and the common electrode (26).

[0062] 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 exhibits an intermediate state between a solid (crystal) and a liquid. The liquid crystal may also 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. The optical properties of the liquid crystal layer (25) may vary depending on the presence or absence of an electric field passing through the liquid crystal layer (25).

[0063] Referring again to FIG. 2, 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 may be provided.

[0064] The cable (20a) can electrically connect the panel driver (30) to the control assembly (50) and the power assembly (60). Additionally, the cable (20a) can electrically connect the panel driver (30) to the liquid crystal panel (20). The cable (20a) may be a flexible flat cable and / or a film cable.

[0065] The panel driver (30) can receive image data from the control assembly (50) and power from the power assembly (60) through the cable (20a). Additionally, the panel driver (30) can provide image data and driving current to the liquid crystal panel (20) through the cable (20a).

[0066] The cable (20a) and the panel driver (30) may be provided as a single unit. For example, the cable (20a) and the panel driver (30) may be implemented as a chip on film (COF) or a tape carrier packet (TCP). In other words, the panel driver (30) may be placed on the cable (20a). However, it is not limited thereto, and the panel driver (30) may also be placed on the liquid crystal panel (20).

[0067] The control assembly (50) may include a control circuit that controls the operation of the liquid crystal panel (20) and the backlight unit (100). The control circuit may process image data received from an external content source, transmit image data to the liquid crystal panel (20), and transmit dimming data to the backlight unit (100). The control assembly (50) may include a processor (91) and a memory (92).

[0068] The power assembly (60) can supply power to the liquid crystal panel (20) and the backlight unit (100). The liquid crystal panel (20) can block or allow light emitted from the backlight unit (100) to pass through using the supplied power. The backlight unit (100) can emit light using the supplied power.

[0069] 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 control assembly (50) may include a control circuit board on which a processor (91) and a memory (92) are mounted. The power assembly (60) may include a power circuit board on which components such as a capacitor, a coil, a resistor element, and a processor are mounted.

[0070] Figures 4 and 5 are exploded perspective views of a backlight unit.

[0071] As illustrated in FIG. 4, the backlight unit (100) may include a light source module (110), a reflective sheet (120), a diffuser plate (130), and an optical sheet (140) that improves the brightness of the emitted light.

[0072] 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).

[0073] 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).

[0074] The reflective sheet (120) can reflect light emitted from a plurality of light sources (111) forward or in a direction close to the forward.

[0075] A plurality of through holes (120a) are formed in the reflective sheet (120) at positions corresponding to each of the plurality of light sources (111) of the light source module (110). The light source (111) of the light source module (110) passes through the through holes (120a) and protrudes forward from the reflective sheet (120), thereby emitting light from the front of the reflective sheet (120). The reflective sheet (120) can reflect the light emitted from the plurality of light sources (111) toward the reflective sheet (120) toward the diffuser plate (130).

[0076] A diffuser plate (130) may be provided in front of the light source module (110) and the reflective sheet (120). The diffuser plate (130) can evenly disperse light emitted from the light source (111) of the light source module (110).

[0077] 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 diffusion sheet (141), a first prism sheet (142), a second prism sheet (143), a reflective polarizing sheet (144), etc.

[0078] The diffusion sheet (141) diffuses light for uniform brightness. Light emitted from the light source (111) is diffused by the diffusion plate (130) and can be diffused again by the diffusion sheet (141) included in the optical sheet (140).

[0079] The first and second prism sheets (142, 143) can increase brightness by concentrating light diffused by the diffusion sheet (141). The first and second prism sheets (142, 143) include a prism pattern in the shape of a triangular prism, and a plurality of these prism patterns are arranged adjacently to form a plurality of band shapes.

[0080] A reflective polarizing sheet (144) is a type of polarizing film that can transmit some of the incident light and reflect others in order to improve brightness. For example, it can transmit polarization in the same direction as a predetermined polarization direction of the reflective polarizing sheet (144) and reflect polarization in a direction different from the polarization direction of the reflective polarizing sheet (144).

[0081] In addition, light reflected by the reflective polarizing sheet (144) is recycled inside the backlight unit (100), and the brightness of the display device (10) can be improved through this light recycling.

[0082] However, the optical sheet (140) is not necessarily limited to the structure shown in FIG. 4, and it is possible to omit some of the sheets shown in FIG. 4 or to include other sheets not shown in FIG. 4.

[0083] Meanwhile, the example of FIG. 4 illustrates a case where the light source module (110) is implemented in a flat plate type. That is, according to the example of FIG. 4, the substrate (112) is implemented in a flat plate shape and a plurality of light sources (111) can be mounted on the substrate (112) in a two-dimensional matrix array.

[0084] A plurality of light sources (111) can be arranged on a substrate (112) at predetermined intervals so that light can be emitted with uniform brightness. Specifically, the plurality of light sources (111) can be arranged such that the distance between one light source and adjacent light sources becomes equal.

[0085] For example, as shown in FIG. 4, a plurality of light sources may be arranged so that a roughly square is formed by four adjacent light sources. In addition, one light source may be arranged adjacent to four light sources, and the distance between one light source and the four light sources adjacent to it may be approximately the same.

[0086] Alternatively, 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.

[0087] However, the arrangement of the plurality of light sources (111) is not limited to the arrangement described above, and as long as the light can be emitted with uniform brightness, no other restrictions are placed on the arrangement of the plurality of light sources (111).

[0088] According to another example, as illustrated in FIG. 5, it is also possible for the light source module (110) to be implemented in a bar type. In this case, the substrate (112) may be implemented in a bar shape and a plurality of light sources (111) may be mounted on the substrate (112). Likewise, the plurality of light sources (111) may be arranged in a predetermined arrangement so that light is emitted with uniform brightness.

[0089] For example, a plurality of light sources (111) may be arranged such that the distance between one light source and adjacent light sources is equal. The plurality of light sources (111) may be arranged at equal intervals, arranged in a zigzag pattern, or arranged in a two-dimensional matrix form.

[0090] When the light source module (110) is implemented as a bar type, a plurality of light source modules (110) can be fixed to the bottom chassis (101). At this time, the plurality of light source modules (110) can be fixed to the bottom chassis (101) according to a predetermined spacing.

[0091] Regardless of whether the light source module (110) is implemented as a flat plate type or a bar type, the light source (111) may employ a device capable of emitting monochromatic light (light having a specific range of wavelengths or light having one peak wavelength, e.g., blue light) or white light (light having multiple peak wavelengths, e.g., light mixed with red light, green light and blue light) in various directions when power is supplied.

[0092] For example, the light source (111) may include a light-emitting diode (LED). The specific structure of the light source will be described below.

[0093] FIG. 6 is a perspective view showing the structure of a light source included in a light source module of a display device, and FIG. 7 is a side cross-sectional view showing the structure of a light source included in a light source module of a display device.

[0094] As illustrated in FIGS. 6 and 7, each of the plurality of light sources (111) may include a light-emitting diode (LED) chip (190) and an optical dome (180). Accordingly, in the embodiments described below, the light source module (110) will be referred to as a light-emitting diode module (110).

[0095] As previously described, a plurality of light sources (111) can pass through a through hole (120a) at the rear of the reflective sheet (120) and protrude toward the front of the reflective sheet (120). Thus, as shown in FIGS. 6 and 7, a portion of the light source (111) and the substrate (112) can be exposed toward the front of the reflective sheet (120) through the through hole (120a).

[0096] The light source (111) may include an electrical / mechanical structure located in an area defined by a through hole (120a) of the reflective sheet (120).

[0097] The light-emitting diode chip (190) can be directly mounted on the substrate (112) in a Chip On Board (COB) manner without separate packaging.

[0098] The light-emitting diode chip (190) can be manufactured as a flip-chip type. When attaching the light-emitting diode, which is a semiconductor device, to a substrate, the electrode pattern of the semiconductor device can be fused directly to the substrate without using an intermediate medium such as a metal lead (wire) or a ball grid array (BGA). In this way, by omitting the metal lead (wire) or ball grid array, the light source (111) can be miniaturized.

[0099] The substrate (112) may be provided with a power supply line (230) and a power supply pad (240) for transmitting an electrical signal or power provided from a control assembly (50) or a power assembly (60) to a light-emitting diode chip (190).

[0100] As shown in FIG. 7, the substrate (112) can be formed by alternately stacking a non-conductive insulation layer (251) and a conductive conduction layer (252).

[0101] A line or pattern through which power or electrical signals pass is formed in the conductive layer (252). The conductive layer (252) may be composed of various materials having electrical conductivity. For example, the conductive layer (252) may be composed of various metal materials such as copper (Cu), tin (Sn), aluminum (Al), or alloys thereof.

[0102] The dielectric of the insulating layer (251) can insulate between the lines or patterns of the conductive layer (252). The insulating layer (251) may be composed of a dielectric for electrical insulation, for example, FR-4.

[0103] The power supply line (230) can be implemented by a line or pattern formed in the conductive layer (252). The power supply line (230) can be electrically connected to the light-emitting diode chip (190) through the power supply pad (240).

[0104] The power supply pad (240) can be formed by exposing a part of the power supply line (230) to the outside.

[0105] A protection layer (253) may be formed on the top layer of the substrate (112) to prevent or suppress damage to the substrate (112) caused by external impact, chemical action (e.g., corrosion), or optical action. As an example, the protection layer (253) may include a photo solder resist (PSR).

[0106] The protective layer (253) can cover the power supply line (230) to prevent the power supply line (230) from being exposed to the outside.

[0107] For electrical contact between the power supply line (230) and the light-emitting diode chip (190), a window may be formed in the protective layer (253) that exposes a portion of the power supply line (230) to the outside. The portion of the power supply line (230) exposed to the outside by the window of the protective layer (253) may form a power supply pad (240).

[0108] At this time, a pair of feed pads (240) corresponding to each of a pair of electrodes (191a, 191b) provided in a flip-chip type light-emitting diode chip (190) may be provided.

[0109] The power supply pad (240) and the (191a, 191b) of the light-emitting diode chip (190) can be electrically contacted by soldering, and power can be supplied to the light-emitting diode chip (190) through the power supply line (230) and the power supply pad (240). When power is supplied, the light-emitting diode chip (190) can emit light. A detailed description regarding soldering will be provided later.

[0110] The optical dome (180) may be provided in a form that covers the light-emitting diode chip (190). The optical dome (180) can prevent or suppress damage to the light-emitting diode chip (190) caused by external mechanical action or external chemical action. Additionally, the optical dome (180) can prevent the light-emitting diode chip (190) from being separated from the substrate (112) by external impact.

[0111] Additionally, the optical dome (180) can increase the light emission efficiency of the light-emitting diode chip (190) through index matching. Specifically, due to the difference in refractive index between the transparent substrate (195) and air, light emitted to the transparent substrate (195) may not be emitted to the outside. The optical dome (180) reduces the difference in refractive index between the transparent substrate (195) and air, thereby allowing light emitted from the light-emitting diode chip (190) to pass through the transparent substrate (195) and the optical dome (180) and be emitted to the outside.

[0112] Additionally, the optical dome (180) can protect the light-emitting diode chip (190) from external electrical action. For example, a charge generated by electrostatic discharge cannot pass through the optical dome (180) and can flow along the outer surface of the optical dome (180).

[0113] The optical dome (180) may have a dome shape that is, for example, cut from a sphere, or a hemispherical shape. The vertical cross-section of the optical dome (180) may be, for example, arc-shaped or semicircular.

[0114] The optical dome (180) may be made of a protective material capable of protecting the light-emitting diode chip (190) from external stimuli. For example, the protective material may include a thermosetting transparent resin. Additionally, the thermosetting transparent resin may be at least one selected from the group including silicone and epoxy resins. A method of forming the optical dome (180) using the protective material will be described later.

[0115] The optical dome (180) may be optically transparent or translucent. Light emitted from the light-emitting diode chip (190) may pass through the optical dome (180) and be emitted to the outside.

[0116] At this time, the dome-shaped optical dome (180) can refract light like a lens. Light emitted from the light-emitting diode chip (190) can be dispersed by being refracted by the optical dome (180).

[0117] In this way, the optical dome (180) can not only protect the light-emitting diode chip (190) from external mechanical, chemical, or electrical action, but also disperse the light emitted from the light-emitting diode chip (190).

[0118] Figure 8 is a side cross-sectional view showing the structure of a light-emitting diode chip.

[0119] Referring to FIG. 8, the light-emitting diode chip (190) may include a transparent substrate (195), an n-type semiconductor layer (193), and a p-type semiconductor layer (192). Additionally, the light-emitting diode chip (190) is provided with a pair of electrodes (191a, 191b) for supplying holes and electrons to the p-type semiconductor layer (192) and the n-type semiconductor layer (193), respectively. Furthermore, a Multi Quantum Wells (MQW) layer (194) is formed between the n-type semiconductor layer (193) and the p-type semiconductor layer (192).

[0120] 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). However, the type of transparent substrate (195) is not limited to this, and various types of substrates provided for semiconductor single crystal growth, such as silicon substrates and GaN substrates, may be used as the transparent substrate (195).

[0121] 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.

[0122] 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).

[0123] 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.

[0124] The first electrode (191a) of the light-emitting diode chip (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.

[0125] When voltage is applied to the light-emitting diode chip (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).

[0126] Electrons and holes can recombine in a depletion layer formed between a p-type semiconductor layer (192) and an 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.

[0127] 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.

[0128] 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 chip (190) can be improved.

[0129] 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.

[0130] The light generated by the recombination of electrons and holes is not emitted in a specific direction, and as shown in FIG. 8, 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.

[0131] A first reflective layer (196) may be provided on the outer side of the transparent substrate (195) (the upper side of the transparent substrate in the drawing). Additionally, a second reflective layer (197) may be provided on the outer side of the p-type semiconductor layer (192) (the lower side of the p-type semiconductor layer in the drawing). That is, the transparent substrate (195), the n-type semiconductor layer (193), the quantum well layer (194), and the p-type semiconductor layer (192) may be disposed between the first reflective layer (196) and the second reflective layer (197).

[0132] 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.

[0133] 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).

[0134] 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. For example, the first reflective layer (196) can reflect light incident at a small angle of incidence and allow light incident at a large angle of incidence to pass through. 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.

[0135] The first reflective layer (196) and the second reflective layer (197) can be formed by stacking materials with different refractive indices. For example, the first reflective layer (196) and the second reflective layer (197) may include a Distributed Bragg Reflector (DBR).

[0136] Hereinafter, a method for manufacturing a light-emitting diode module and a manufacturing system according to one embodiment will be described. The light-emitting diode module manufactured by the method and manufacturing system according to one embodiment may be the light-emitting diode module (110) described above. That is, the light-emitting diode module (110) can be manufactured by mounting a light source (111) on a substrate (112), and the light source (111) includes a light-emitting diode chip (190) and an optical dome (180) surrounding it.

[0137] A light-emitting diode module (110) manufactured by a manufacturing method and manufacturing system according to one embodiment may be included in a backlight unit (100) of a display device (10) as described above. At this time, the light-emitting diode module (110) may be of a flat plate type or a bar type. However, this is merely an example of use for the light-emitting diode module (110), and it may be used for other purposes other than the backlight unit of the display device (10).

[0138] There are no restrictions on the use of the light-emitting diode module (110) manufactured by the manufacturing method and manufacturing system according to one embodiment, but for the sake of specific explanation in the following embodiments, the case where the light-emitting diode module (110) is used in the backlight unit of a display device (10) is described as an example.

[0139] FIG. 9 is a flowchart relating to a method for manufacturing a light-emitting diode module according to one embodiment, and FIG. 10 is a block diagram showing the configuration of a manufacturing system for manufacturing a light-emitting diode module according to one embodiment.

[0140] Referring to FIG. 9, a method for manufacturing a light-emitting diode module according to one embodiment includes the steps of mounting a light-emitting diode chip on the surface of a substrate (310), spraying a protective material onto the light-emitting diode chip mounted on the surface of the substrate (320), and curing the protective material sprayed onto the light-emitting diode chip by a reflow process (330).

[0141] Here, the substrate is a substrate (112) having a power supply line (230) for supplying power to a light-emitting diode chip (190) and a power supply pad (240) for electrical connection between the power supply line (230) and the light-emitting diode chip (190), and may be, for example, a printed circuit board.

[0142] Surface Mount Technology may be applied to mount a light-emitting diode chip (190) on the surface of a substrate (112). Surface Mount Technology is a technology for directly mounting a component on the surface of a substrate and can be implemented by a surface mount device (410) as shown in FIG. 10.

[0143] Referring to FIG. 10, a manufacturing system according to one embodiment includes a surface mount device (410) and a spraying device (420).

[0144] The surface mount device (410) can mount a plurality of light-emitting diode chips (190) on a substrate (112) using soldering.

[0145] The dispensing device (420) can dispense a protective material onto a plurality of light-emitting diode chips (190) mounted on the surface of the substrate (112). As described above, the protective material may be at least one selected from the group comprising silicon and epoxy resin.

[0146] When forming the aforementioned optical dome (180) by spraying a protective material, the spraying device (420) can spray the protective material to surround the light-emitting diode chip (190).

[0147] The shape of the optical dome (180) may vary depending on the viscosity of the silicone or epoxy resin. For example, if the optical dome (180) is manufactured using silicone with a thixotropic index of approximately 2.7 to 3.3 (preferably 3.0), the optical dome (180) may be formed with a dome ratio of approximately 0.25 to 0.31 (preferably 0.28), which represents the ratio of the height of the dome to the diameter of the bottom surface of the dome (height of the dome / diameter of the bottom surface). An optical dome (180) manufactured with silicone having a thixotropic index of approximately 2.7 to 3.3 (preferably 3.0) may have a bottom surface diameter of approximately 2.5 mm and a height of approximately 0.7 mm.

[0148] Therefore, a protective material can be selected by considering the shape of the optical dome (180) to be formed.

[0149] However, the type of protective material is not limited to silicone or epoxy resin, and any material capable of implementing the function of the optical dome (180) described above can be the protective material sprayed onto the light-emitting diode chip (190).

[0150] Meanwhile, the liquid protective material sprayed onto the light-emitting diode chip (190) must be cured so that the aforementioned optical dome (180) can be formed. If an oven is used to cure the protective material, the curing time is long. For this reason, multiple substrates (112) sprayed with the protective material are collected and cured in the oven at once; this process complicates the entire manufacturing process, and the uniformity of curing is reduced because there is a difference in the time the protective material is sprayed depending on the substrate (112).

[0151] Accordingly, in the method for manufacturing a light-emitting diode module according to one embodiment, a protective material is cured by a reflow process.

[0152] A reflow process can also be applied when the surface mount device (410) mounts a light-emitting diode chip (190) on the surface of the substrate (112). That is, the surface mount device (410) may include a reflow device, and not only the mounting of the light-emitting diode chip (190) but also the curing of the protective material sprayed on the light-emitting diode chip (190) can be performed using the reflow device of the surface mount device (410).

[0153] A substrate (112) on which a light-emitting diode chip (190) is mounted on the surface by a surface mount device (410) can be transported by a conveyor belt (C) to a spraying device (420). According to one embodiment, a substrate (112) on which a protective material is sprayed onto the light-emitting diode chip (190) by a spraying device (420) can also be transported by a conveyor belt (C) to a spraying device (420). In this case, the time required from spraying the protective material to curing can be shortened and the process can be simplified.

[0154] Here, the conveyor belt (C) that transports the substrate (112) from the surface mount device (410) to the spraying device (420) and the conveyor belt (C) that transports the substrate (112) from the spraying device (420) to the surface mount device (410) may be separate from each other, or they may be the same depending on the design of the manufacturing equipment.

[0155] In this way, when the protective material is cured using a reflow process, the protective material can be transferred to the reflow process as soon as it is sprayed onto the substrate (112), without having to cure multiple substrates together as in the case of using an oven.

[0156] Therefore, the manufacturing process of light-emitting diode modules can be simplified and manufacturing time shortened, and non-uniformity in curing caused by differences in the spraying time of protective materials for each substrate can be prevented.

[0157] In addition, the time required for the curing of the protective material itself can also be shortened.

[0158] In addition, since the time from spraying the protective material to curing is shortened, the protective material can be cured into a desired shape, which is advantageous for forming a hemispherical optical dome (180) as described above.

[0159] In the example described above, the reflow equipment used to mount the light-emitting diode chip (190) on the substrate (112) and the reflow equipment used to cure the protective material sprayed onto the light-emitting diode chip (190) were described as being the same, but the embodiments of the method for manufacturing the light-emitting diode module are not limited thereto. Therefore, it is also possible to cure the protective material using a separate reflow equipment.

[0160] The aforementioned effects can be obtained even when using a separate reflow device. However, when the protective material is cured using the reflow device provided in the surface mount device (410), separate equipment for curing the protective material is not required, thereby simplifying the manufacturing system and reducing manufacturing equipment costs. In the embodiments described below, the case in which the protective material is cured using the reflow device provided in the surface mount device (410) is explained as an example.

[0161] FIG. 11 is a flowchart illustrating the mounting process of a light-emitting diode chip in a method for manufacturing a light-emitting diode module according to one embodiment, and FIG. 12 is a block diagram illustrating a surface mount device of a manufacturing system for a light-emitting diode module according to one embodiment.

[0162] Referring to FIG. 11, the step (310) of mounting a light-emitting diode chip on the surface of a substrate may include the step (311) of forming solder on a pad formed on the surface of the substrate, the step (312) of placing the light-emitting diode chip on the formed solder, and the step (313) of curing the solder by a reflow process.

[0163] Referring to FIG. 12, the surface mount device (410) may include a solder forming device (411) for forming solder on a pad formed on the surface of a substrate (112), a mounting device (412) for placing a light-emitting diode chip on the formed solder, and a reflow device (413) for performing a reflow process.

[0164] The solder forming device (411) can supply solder paste onto a pad formed on the surface of the substrate (112). For example, the solder paste may include solder powder and flux.

[0165] As described above, a plurality of light-emitting diode chips (190) can be mounted on a single substrate (112). Feed pads (240) for electrical contact with the light-emitting diode chips (190) can be formed in a number corresponding to the number of light-emitting diode chips (190).

[0166] The pad to which the solder paste is supplied includes a power supply pad (240). That is, a cream-type solder paste (241) can be applied to a number of power supply pads (240) corresponding to the number of light-emitting diode chips (190).

[0167] The solder forming device (411) may supply solder paste onto the pad by applying a screen printing method of solder paste, or it may supply solder paste onto the pad by applying a dispensing method of dispensing a certain amount of solder paste by a nozzle. As long as it can supply solder paste onto the pad, there are no restrictions on the method.

[0168] The mounting device (412) mounts a light-emitting diode chip (190) on a pad on which solder is formed. At this time, the first electrode (191a) and the second electrode (191b) of the light-emitting diode chip (190) can be aligned and positioned to match the respective positions of the feed pad (240). For example, the mounting device (412) can be implemented by a pick-and-place device.

[0169] The reflow device (413) performs a reflow process in which the solder between the pad of the substrate (112) and the light-emitting diode chip (190) is heated to a certain temperature to melt it, and then cooled to cure it. As the melted solder cures, the light-emitting diode chip (190) is bonded to the pad of the substrate (112), and electrical contact is established between the two.

[0170] To distinguish between the reflow process used for curing the solder and the reflow process used for curing the protective material, the reflow process used for curing the solder shall be referred to as the first reflow process, and the reflow process used for curing the protective material shall be referred to as the second reflow process.

[0171] The substrate (112) between the solder forming device (411), the mounting device (412), and the reflow device (413) may be transported by a conveyor belt (C). However, the embodiment of the manufacturing system for the light-emitting diode module is not limited to this, and depending on the design of the manufacturing facility, it is possible for the substrate (112) to be transported in a manner other than the conveyor belt (C). For example, it is possible for the substrate (112) to be transported manually.

[0172] The substrate (112), which has been soldered by the first reflow process in the reflow device (413), is transferred to the spraying device (420). As described above, the spraying device (420) sprays a protective material onto the light-emitting diode chip (190) mounted on the substrate (112).

[0173] The substrate (112) on which the protective material is sprayed onto the light-emitting diode chip (190) is transferred again to the reflow device (413). The reflow device (413) can cure the protective material by a second reflow process, and the cured protective material can form an optical dome (180) surrounding the light-emitting diode chip (190) mounted on the surface of the substrate (112). That is, the optical dome (180) can be formed by the step of spraying the protective material onto the light-emitting diode chip (190) and the step of curing the sprayed protective material.

[0174] FIG. 13 is a graph showing an example of a temperature profile applied to a second reflow process in a method for manufacturing a light-emitting diode module according to one embodiment.

[0175] Temperature profiles such as heating temperature, heating time, cooling temperature, and cooling time in the reflow process may vary depending on the material to be cured. The material to be cured in the first reflow process is different from the material to be cured in the second reflow process. Therefore, the temperature profile in the first reflow process and the temperature profile in the second reflow process may differ from each other.

[0176] For example, in the first reflow process, when curing a solder with a melting point of 150°C, the solder can be heated to a temperature of 150°C or higher, and when curing a solder with a melting point of 230°C, the solder can be heated to a temperature of 230°C or higher.

[0177] In addition, when curing silicon in the second reflow process, the silicon can be heated to a temperature in the range of 160 to 200°C.

[0178] The graph in Fig. 13 shows the temperature profile created while curing silicon by the second reflow process.

[0179] Referring to Fig. 13, the silicon can be heated to a temperature of around 180°C, maintained at that temperature for a certain period of time, and then cooled. It can be confirmed that the time required for curing is within 10 minutes. Since curing takes several hours when using an oven, the time required for curing can be shortened by using a reflow process.

[0180] According to the manufacturing method and manufacturing system of the light-emitting diode module described so far, by curing the protective material sprayed onto the light-emitting diode chip through a reflow process, the complexity of the manufacturing process can be reduced, and not only the total manufacturing time but also the time required for curing the protective material itself can be shortened.

[0181] In addition, since the substrate sprayed with the protective material immediately begins curing via the reflow process, non-uniformity of curing between substrates can be resolved, and the protective material can be cured into a desired shape.

[0182] In addition, if the protective material is cured using the reflow device used to mount the light-emitting diode chip on the substrate, it is possible to simplify the manufacturing equipment and reduce costs.

[0183] As described above, the disclosed embodiments have been explained with reference to the attached drawings. Those skilled in the art will understand that the disclosed embodiments may be implemented in forms different from the disclosed embodiments without changing the technical concept or essential features of the disclosed embodiments. The disclosed embodiments are illustrative and should not be interpreted restrictively. Explanation of the symbols

[0184] 10: Display device 11: Main body 12: Screen 20: Liquid crystal panel 30: Panel driver 50: Control assembly 60: Power Assembly 100: Backlight Unit 110: Light source module 111: Light source 112: Substrate 120: Reflective sheet 120a: Through hole 130: Diffusion plate 240: Power supply pad 230: Power supply line 180: Optical dome 190: Light emitting diode 191a: First electrode 191b: Second electrode 192: p-type semiconductor layer 193: n-type semiconductor layer 194: Quantum well layer 195: Transparent substrate

Claims

Claim 1 A method for manufacturing a light-emitting diode module comprising: a step of forming solder on a pad formed on the surface of a substrate; a step of placing a light-emitting diode chip on the formed solder; a step of transferring the substrate on which the light-emitting diode chip is placed to a reflow device; a step of curing the solder by a first reflow process; a step of transferring the substrate on which the light-emitting diode chip is mounted to a spraying device; a step of spraying a protective material onto the light-emitting diode chip mounted on the surface of the substrate by the spraying device; a step of transferring the substrate on which the protective material is sprayed onto the light-emitting diode chip from the spraying device to the reflow device; and a step of curing the protective material sprayed onto the light-emitting diode chip by a second reflow process to form an optical dome surrounding the light-emitting diode chip. Claim 2 delete Claim 3 delete Claim 4 In claim 1, the method for manufacturing a light-emitting diode module comprises a protective material including a thermosetting transparent resin. Claim 5 delete Claim 6 delete Claim 7 In claim 1, the optical dome is a method for manufacturing a light-emitting diode module that disperses light emitted from the light-emitting diode chip. Claim 8 A method for manufacturing a light-emitting diode module according to claim 1, wherein the light-emitting diode chip comprises: a flip-chip light-emitting diode; and a reflector disposed on the light-emitting surface of the flip-chip light-emitting diode. Claim 9 A method for manufacturing a light-emitting diode module according to claim 1, wherein the step of curing the protective material comprises heating the protective material to a temperature in the range of 160 to 200 ℃ by the second reflow process. Claim 10 A method for manufacturing a light-emitting diode module according to claim 1, wherein the step of curing the solder comprises heating the solder to a temperature in the range of 230 to 270 ℃ by the first reflow process. Claim 11 delete Claim 12 delete Claim 13 delete Claim 14 delete Claim 15 delete Claim 16 delete

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