KR20100127893A - Light emitting diode array and liquid crystal display device using same - Google Patents

Abstract

The present invention relates to a light emitting diode array that can be used as a light source of a backlight unit, wherein a first group of LED packages, a first flexible circuit board on which the first group of LED packages are mounted, and the first flexible circuit board are mounted. A first LED array comprising a first metal core; And a second LED array including a second group of LED packages, a second flexible circuit board on which the second group of LED packages are mounted, and a second metal core on which the second flexible circuit board is mounted.

Description

LIGHT EMITTING DIODE ARRAY AND LIQUID CRYSTAL DISPLAY USING THE SAME}

The present invention relates to a light emitting diode array which can be used as a light source of a backlight unit, and a liquid crystal display for displaying an image using the same.

The liquid crystal display of the active matrix driving method displays a moving image using a thin film transistor (hereinafter referred to as TFT) as a switching element. The liquid crystal display device can be miniaturized compared to a cathode ray tube (CRT), which is applied to a display device in a portable information device, an office device, a computer, and a TV, and is rapidly replacing a cathode ray tube.

The liquid crystal display device includes a liquid crystal display panel, a backlight unit for irradiating light to the liquid crystal display panel, a light source driving circuit for driving a light source of the backlight unit, a data driving circuit for supplying a data voltage to data lines of the liquid crystal display panel, and a liquid crystal And a gate driving circuit for supplying scan pulses to gate lines (or scan lines) of the display panel, and a control circuit for controlling the driving circuits.

Recently, a light emitting diode (hereinafter referred to as "LED") has been adopted as the backlight unit. The higher the temperature, the lower the efficiency and the lifetime of the light emitting diode. In order to solve this problem, conventionally, LED packages are mounted on a metal printed circuit board (hereinafter referred to as "PCB") which is advantageous for heat dissipation. However, since the metal PCB is an expensive substrate device material having a structure in which a metal layer and an organic insulating layer are stacked, the metal PCB serves to increase the cost of the backlight unit and the liquid crystal display device. Heat dissipated from the LED package is not emitted high enough because it is released to the outside through the organic insulating layer in the metal PCB. In order to slim down the liquid crystal display device, the thickness and width of the metal PCB are also reduced, thereby limiting the number of wirings formed on the metal PCB, and heat dissipation of LED packages becomes more difficult.

In order to increase the uniformity and brightness of the light irradiated onto the liquid crystal display panel, LED packages are densely mounted on the metal PCB. Because of this, the heat dissipated from the LED packages is not dissipated, which reduces the life span and efficiency of the LED packages, and may cause overheating of components such as the light guide plate disposed near the LED packages, which may cause deformation or damage of the components. have.

An object of the present invention is to solve the problems of the prior art to increase the number of wires connected to the LED package without hindering the slimming of the liquid crystal display device and to increase the heat dissipation effect of the LED package An LED array and a liquid crystal display using the same are provided.

In order to achieve the above object, the LED array according to the embodiment of the present invention, the first group of LED packages, the first flexible circuit board mounted with the LED package of the first group, and the first flexible circuit board is mounted A first LED array comprising a first metal core; And a second LED array including a second group of LED packages, a second flexible circuit board on which the second group of LED packages are mounted, and a second metal core on which the second flexible circuit board is mounted.

LED array according to another embodiment of the present invention is a metal core with a groove formed on one side; A first flexible circuit board mounted at one side of the groove and mounted with a first group of LED packages; And a second flexible circuit board mounted on the other side of the groove and mounted with a second group of LED packages.

The first group of LED packages and the second group of LED packages are alternately arranged.

The liquid crystal display of the present invention includes a backlight unit including the LED array; And a liquid crystal display panel which displays an image by controlling the transmittance of light from the backlight unit by using liquid crystal molecules controlled by an electrical signal.

As described above, the present invention separates the flexible circuit board and the metal core into two or more, and mounts the LED packages with a wide distance on the flexible circuit boards. The present invention assembles the metal cores in a structure surrounding three sides except the light emitting side of the LED package. As a result, the present invention can increase the number of interconnections formed on the flexible circuit boards without separating the flexible circuit boards and inhibiting the slimming of the liquid crystal display device. In addition, the present invention can increase the distance between the LED package to dissipate heat from the LED package and expand the heat dissipation surface by the metal core structure surrounding the three sides of the LED package to increase the heat dissipation effect.

A method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention includes a substrate cleaning process, a substrate patterning process, an alignment film forming / rubbing process, a substrate bonding and liquid crystal dropping process, a driving circuit mounting process, a module assembly process, and the like. do.

The substrate cleaning process removes contaminants on the upper and lower glass substrate surfaces of the liquid crystal display panel with the cleaning liquid. The substrate patterning process is to form and pattern various thin film materials such as signal wiring, thin film transistor (TFT), and pixel electrode including data lines and gate lines on the lower glass substrate, and a black matrix on the upper glass substrate. And forming and patterning various thin film materials such as color filters and common electrodes. In the alignment film forming / rubbing process, an alignment film is coated on glass substrates and the alignment film is rubbed or rubbed with a rubbing cloth. Through such a series of processes, the lower glass substrate of the liquid crystal display panel includes data lines to which a video data voltage is supplied, gate lines and data lines that intersect the data lines and are sequentially supplied with scan signals, that is, gate pulses. A TFT and TFT array including TFTs formed at intersections of gate lines, pixel electrodes of a liquid crystal cell connected to 1: 1 with TFTs, a storage capacitor, and the like are formed. The shift register of the gate driving circuit that generates the scan signal may be formed simultaneously with the pixel and the TFT array in the substrate patterning process. A black matrix, a color filter, and a common electrode are formed on the upper glass substrate of the liquid crystal display panel. The common electrode is formed on the upper glass substrate in a vertical electric field driving method such as twisted nematic (TN) mode and vertical alignment (VA) mode, and a horizontal electric field such as IPS (In Plane Switching) mode and FFS (Fringe Field Switching) mode. The driving method is formed on the lower glass substrate together with the pixel electrode. A polarizing plate and a polarizing plate protective film are attached to each of the upper and lower glass substrates.

In the substrate bonding and liquid crystal dropping process, a sealant is drawn on one of the upper and lower glass substrates of the liquid crystal display panel and the liquid crystal is dropped onto the other substrate in the vacuum chamber. For example, when the liquid crystal is dropped on the lower glass substrate, an ultraviolet curable sealant is formed on the upper glass substrate in the vacuum chamber, the upper glass substrate on which the sealant is formed is inverted and fixed to the upper stage, and the liquid crystal is dropped. The lower glass substrate is fixed to the lower stage. Subsequently, the substrate bonding process and the liquid crystal dropping process align the upper glass substrate and the lower glass substrate, and then drive the vacuum pump to adjust the pressure of the vacuum chamber to any one of the upper and lower glass substrates. Apply pressure to bond the upper and lower glass substrates together. At this time, the cell gap of the liquid crystal layer is set larger than the cell gap of the design value. Subsequently, when nitrogen (N ₂ ) is introduced into the vacuum chamber to adjust the pressure of the vacuum chamber to atmospheric pressure, the cell gap of the liquid crystal display panel is adjusted to the cell gap of the designed value by the pressure difference between the bonded glass substrates and the vacuum chamber. When the ultraviolet light source is irradiated to the ultraviolet curable sealant through the upper glass substrate or the lower glass substrate of the liquid crystal display panel with the cell gap adjusted to the designed value, the sealant is cured.

The driving circuit mounting process uses a chip on glass (COG) process or a tape automated bonding (TAB) process to mount a source drive integrated circuit (IC) of a data driving circuit on a lower glass substrate of a liquid crystal display panel. Connect the source ICs of the driver circuit to the source PCB. The gate driving circuit may be directly formed on the lower glass substrate of the liquid crystal display panel at the same time as the pixel array in a GIP process and may be attached to the lower glass substrate in a TAB process. In the driving circuit mounting process, the source PCB is connected to the control PCB or the system board using a flexible printed circuit board such as a flexible printed circuit board (FPC) and a flexible flat cable (FFC).

The module assembly process assembles a backlight unit including an LED array and a liquid crystal display panel using a liquid crystal module (LCM) using case members such as a support main, a bottom cover, and a top case. The LED array has a structure as shown in FIGS. 2 to 6 and 10 to 12.

The manufacturing method of the liquid crystal display according to the exemplary embodiment of the present invention may further include an inspection process and a repayment process. The inspection process includes inspection of integrated circuits, signal wiring of data lines and gate lines formed on the lower glass substrate, electrical inspection for detecting defects of TFT and pixel electrodes, electrical inspection performed after substrate bonding and liquid crystal dropping, and liquid crystal modules. Lighting of the backlight unit to detect a failure of the liquid crystal module. The repair process repairs signal wiring defects and TFT defects that are determined to be repairable by the inspection process.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 1 to 14.

1 and 2, a liquid crystal display according to an exemplary embodiment of the present invention includes a data driving circuit 12 connected to a liquid crystal display panel 10 and data lines D1 to Dm of the liquid crystal display panel 10. ), A gate driving circuit 13 connected to the gate lines G1 to Gn of the liquid crystal display panel 10, a timing controller 11 for controlling the data driving circuit 12 and the gate driving circuit 13, and the like. It is provided.

In addition, the liquid crystal display according to the exemplary embodiment of the present invention includes a backlight unit 16 for irradiating light to the liquid crystal display panel 10.

The liquid crystal display panel 10 includes an upper glass substrate and a lower glass substrate facing each other with a liquid crystal layer interposed therebetween. The liquid crystal display panel 10 includes a pixel array for displaying video data. The pixel array of the lower glass substrate includes TFTs formed at intersections of the data lines D1 to Dm and the gate lines G1 to Gn, and a pixel electrode connected to the TFTs. Each of the liquid crystal cells of the pixel array is driven by the voltage difference between the pixel electrode 1 charging the data voltage through the TFT and the common electrode 2 to which the common voltage Vcom is applied to transmit light incident from the backlight unit. Adjust the amount to display an image of the video data.

A black matrix, a color filter, and a common electrode are formed on the upper glass substrate of the liquid crystal display panel 10. The common electrode 2 is formed on the upper glass substrate in the vertical electric field driving method such as TN mode and VA mode, and on the lower glass substrate together with the pixel electrode 1 in the horizontal electric field driving method such as IPS mode and FFS mode. Is formed.

A polarizing plate is attached to each of the upper glass substrate and the lower glass substrate of the liquid crystal display panel 10, and an alignment layer for setting the pre-tilt angle of the liquid crystal is formed.

The liquid crystal mode of the liquid crystal display panel 10 applicable to the present invention may be implemented in any liquid crystal mode as well as the above-described TN mode, VA mode, IPS mode, FFS mode. In addition, the liquid crystal display of the present invention may be implemented in any form, such as a transmissive liquid crystal display, a transflective liquid crystal display, a reflective liquid crystal display. The transmissive liquid crystal display and the transflective liquid crystal display require a backlight unit. In the reflective LCD, a backlight unit or a front light unit may be installed as an auxiliary light source. The backlight unit may be implemented as a direct type backlight unit or an edge type backlight unit. 13 is an example illustrating a cross-sectional structure of an edge type backlight unit, and FIG. 14 is an example illustrating a cross-sectional structure of a direct type backlight unit.

The data driving circuit 12 includes a plurality of source drive ICs. Each of the source drive ICs samples and latches digital video data RGB input from the timing controller 11 and converts the digital video data RGB into data of a parallel data system. Each of the source drive ICs converts the digital video data converted by the parallel data transmission scheme into an analog gamma compensation voltage using the positive / negative gamma reference voltages, so that the positive / negative analog video data voltage to be charged in the liquid crystal cells. Occurs. Each of the source drive ICs supplies the data voltages to the data lines D1 to Dm while inverting the polarity of the positive / negative analog video data voltage according to the polarity control signal POL from the timing controller 11. .

The gate driving circuit 13 includes a plurality of gate drive ICs. The gate driving circuit 13 includes a shift register that sequentially shifts the gate driving voltage in response to the gate control signals GSP, GSC, and GOE from the timing controller 11, and gate pulses (or scan pulses) on the gate lines. ) Are supplied sequentially.

The timing controller 11 receives the RGB digital video data, the vertical synchronization signal (Vsync), the horizontal synchronization from the system board 14 through an interface receiving circuit such as a low voltage differential signaling (LVDS) interface and a transition minimized differential signaling (TMDS) interface. A timing signal such as a signal Hsync, a data enable signal DE, a dot clock CLK, and the like are received. The timing controller 11 may transmit RGB digital video data to the source drive ICs in a mini LVDS interface. If RGB digital video data are transmitted to the source drive ICs in a mini LVDS interface manner, the timing controller 11 does not generate a source start pulse SSP and a source sampling clock SSP. The timing controller 11 uses the timing signals Vsync, Hsync, DE, and CLK to control the source control signals SSP, SSC, SOE, and POL, and the gate control to control the gate drive ICs. Generate signals GSP, GSC, GOE. The timing controller 11 controls the gate timing control signal so that digital video data input at a frame frequency of 60 Hz can be reproduced in the pixel array of the liquid crystal display panel 10 at a frame frequency of 60 x i (i is a positive integer) Hz. And the frequency of the data timing control signal can be multiplied by a frame frequency reference of 60 x i Hz.

The data control signal includes a source start pulse (Source, Start Pulse, SSP), a source sampling clock (SSC), a source output enable signal (Source Output Enable, SOE), and the like. The source start pulse SSP controls the data sampling start time of the data driving circuit 12. The source sampling clock SSC is a clock signal that controls the sampling operation of data in the data driving circuit 12 based on the rising or falling edge. If the signal transmission system between the timing controller 11 and the data driver circuit 12 is a mini LVDS interface, the source start pulse SSP and the source sampling clock SSC may be omitted as described above. The polarity control signal POL inverts the polarity of the data voltage output from the data driving circuit 12 in a period of N (N is a positive integer) horizontal period. The source output enable signal SOE controls the output timing of the data driver circuit. Each of the source drive ICs has a charge share voltage or a common voltage Vcom in response to a pulse of the source output enable signal SOE when the polarity of the data voltage supplied to the data lines D1 to Dm is changed. ) Is supplied to the data lines D1 to Dm, and a data voltage is supplied to the data lines during the low logic period of the source output enable signal SOE. The charge share voltage is an average voltage of neighboring data lines to which data voltages having opposite polarities are supplied.

The gate control signals GSP, GSC, and GOE include a gate start pulse GSP, a gate shift clock GSC, a gate output enable signal GOE, and the like. The gate start pulse GSP controls the timing of the first gate pulse. The gate shift clock GSC is a clock signal for shifting the gate start pulse GSP. The gate output enable signal GOE controls the output timing of the gate driving circuit 13.

The system board 14 includes a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal DE, a dot clock CLK, etc. together with RGB video data input from a broadcast receiving circuit or an external video source. The timing signal of the signal is transmitted to the timing controller 11 through the LVDS interface or the TMDS interface transmission circuit. The system board 14 includes a graphics processing circuit such as a scaler that interpolates the resolution of RGB video data input from a broadcast receiving circuit or an external video source according to the resolution of the liquid crystal display panel and processes the signal interpolation.

The backlight unit 16 may be implemented as an edge type backlight unit or a direct type backlight unit using the LED array 100 as shown in FIGS. 2 to 6 and 10 to 12 as a light source. In the edge type backlight unit, as illustrated in FIG. 13, the LED array 100 is disposed to face the side surface of the light guide plate 24, and a plurality of optical sheets are disposed between the liquid crystal display panel 10 and the light guide plate 24. . In the direct type backlight unit, as shown in FIG. 14, a plurality of optical sheets 146 and a diffusion plate 145 are stacked below the liquid crystal display panel 10 and a plurality of light sources are disposed below the diffusion plate 145. Has a structure. The light source of the direct backlight unit may include a Cold Cathode Fluorescent Lamp (CCFL) or an External Electrode Fluorescent Lamp (EEFL) together with the LED array 100 or the LED array 100.

2 to 6 are diagrams illustrating the LED array 100 according to the first embodiment of the present invention.

2 and 3, the LED array 100 of the present invention includes a first LED array and a second LED array.

The first LED array includes a first flexible circuit board 22u on which the first group of LED packages 23u are mounted, and a first metal core 21u on which the first flexible circuit board 22u is mounted.

Each of the first group of LED packages 23u are side view type LED packages in which light is emitted from the side. Each of these side view type LED packages 23u has a larger side height h that emits light than the thickness width w, as shown in FIG. Meanwhile, conventional side view type LED packages have a structure in which the side height h is smaller than the thickness width w. Each of the first LED packages 23u has a structure in which the side height h is greater than the thickness width w, as shown in FIG. 3, but may be implemented as an existing side view type LED package. The first group of LED packages 23u are mounted on the first flexible circuit board 22u. Wirings for connecting the cathode terminal leads and the anode terminal leads of each of the first group of LED packages 23u to an external power source are formed on the first flexible printed circuit board 22u. The first flexible circuit board 22u may be selected from a flexible printed circuit board (FPCB), a flexible wire (FW), a flexible circuitry (FC), and the like. The spacing between the first group of LED packages 23u is wide enough that one or more LED packages can be placed so that the heat source can be sufficiently dispersed. The first metal core 21u has a cross section having an “L” shape so that one side portion is recessed. The first flexible circuit board 22u having the first group of LED packages 23u mounted thereon is mounted on the horizontal surface of the recessed portion of the first metal core 21u through an adhesive, an adhesive heat dissipation pad, a screw, and the like. The first metal core 21u is made of a high thermal conductive metal such as aluminum (Al) copper (Cu) to emit heat generated from the LED packages 23u to the outside. The side wall of the first metal core 21u is sufficiently thicker than the horizontal surface of the concave portion in order to enhance the heat dissipation effect of the LED packages 23u. The outer surface of the first metal core 21u may be embossed like a heat sink structure to further enhance the heat dissipation effect. Heat radiated from the first metal core 21u is emitted to the outside through the metal cover member of the liquid crystal display such as the bottom cover.

The second LED array includes a second flexible circuit board 22d on which the second group of LED packages 23d are mounted, and a second metal core 21d on which the second flexible circuit board 22d is mounted.

Each of the second group of LED packages 23d is a side view type LED package in which light is emitted from the side. Each of these side view type LED packages 23d has a larger side height h that emits light than the thickness width w, similar to those of the first group described above. Each of the second LED packages 23d may have a structure in which the side height h is greater than the thickness width w, as shown in FIG. 3, but may be implemented as an existing side view type LED package. The second group of LED packages 23d are mounted on the second flexible circuit board 22d. Wirings for connecting the cathode terminal leads and the anode terminal leads of each of the second group of LED packages 23d to the external power supply are formed on the second flexible circuit board 22d. The second flexible circuit board 22d may be selected from FPCB, FW, and FC. The spacing between the second group of LED packages 23d is wide enough that one or more LED packages can be placed so that the heat source can be sufficiently dispersed. The second metal core 21d has a cross section of an “L” shape so that one side portion is recessed. The second flexible circuit board 22d on which the LED package 23d of the second group is mounted is mounted on the horizontal surface of the recessed portion of the second metal core 21d through an adhesive, an adhesive heat dissipation pad, a screw, and the like. The second metal core 21d is made of a high thermal conductive metal such as aluminum (Al) copper (Cu) to emit heat generated from the second group of LED packages 23d to the outside. The sidewall of the second metal core 21d is sufficiently thicker than the horizontal surface of the concave portion in order to enhance the heat dissipation effect of the LED packages 23d of the second group. The outer surface of the second metal core 21d may be embossed like a heat sink structure to further enhance the heat dissipation effect. Heat radiated from the second metal core 21d is discharged to the outside through the metal cover member of the liquid crystal display such as the bottom cover.

The first LED array and the second LED array are assembled such that the first group of LED packages 23u and the second group of LED packages 23d are alternately arranged in a row as shown in FIGS. 2 to 6. Each of the LED packages 23u and 23d is a combination of R LED chip + G LED chip + B LED chip, or a combination of R LED + 2 G LED + B LED chip to emit white light or different It can be selected as a white LED package that emits white light, including two LED chips that generate colored light and a silicon layer containing phosphors. In addition, the LED packages 23u and 23d are combined into the R LED package 23u of the first group, the G LED package 23d of the second group, and the B LED package 23u of the first group to emit white light. You may. 5 is a cross-sectional view illustrating an example in which the LED array 100 is employed as a light source of the edge type backlight unit.

7A and 7B are experimental results of comparing the conventional LED array and the LED array of the present invention with experimental results when only heat conduction is given as an experimental variable. In this experiment, the conventional LED package and the LED package of the present invention were set under the same conditions. Figure 7a is a result of the heat conduction experiment of the conventional LED array employing a flat metal PCB. FIG. 7B is a heat conduction experiment result of the LED array of the present invention having the structure as shown in FIGS. According to the experimental results, when only thermal conductivity is applied, the conventional LED array has a heat distribution of 110 ° C to 109.89 ° C. The LED array of the present invention was able to obtain the experimental results of about 110 ℃ ~ 109.71 ℃ when only the thermal conductivity is applied. Therefore, considering only the heat conduction characteristics, the LED array of the present invention has a heat dissipation effect similar to that of the conventional LED array.

The LED array of the present invention has a significantly improved heat dissipation effect compared to the conventional LED array in an environment having heat convection conditions similar to the actual environment of the liquid crystal display device.

8A and 8B are experimental results of comparing the conventional LED array and the LED array of the present invention with experimental results when heat conduction and backside convection are applied as experimental variables. In this experiment, the conventional LED package and the LED package of the present invention were set under the same conditions. FIG. 8A shows the results of thermal conduction and backside convection experiments of a conventional LED array employing a flat metal PCB. FIG. 8B is a result of thermal conduction and backside tropical current experiments of the LED array of the present invention having the structure shown in FIGS. 2 to 6. According to the results of this experiment, the conventional LED array has a heat distribution of 110 ° C. to 108.99 ° C. when heat conduction and rear tropical flow are applied together. When the LED array of the present invention is applied together with the thermal conductivity and the tropical backflow, the experimental results of about 110 ℃ ~ 106.6 ℃ could be obtained. Therefore, considering only the heat conduction characteristics, the LED array of the present invention has a heat dissipation effect similar to that of the conventional LED array. The difference in the heat dissipation effect is to increase the spacing between the LED package in the LED array of the present invention to increase the heat dissipation effect between the LED package compared to the conventional LED array and the metal core (21u, 21d) of the present invention 'L' cross section This is due to the design of the structure in which the structure is symmetrically combined.

FIG. 9 is a view of the heat dissipation effect of the conventional LED and the LED array according to the present invention. It was separated when considered. The LED array of the present invention design the metal core in a shape to enclose the side and the back of the LED package except for the light emitting part to increase the dispersion distance between the LED package. Therefore, as can be seen in Figure 9, the present invention can increase the heat dissipation effect and heat dissipation effect of the LED package in the actual driving environment as compared to the conventional LED array. In addition, the present invention provides a first flexible circuit board 22u on which a first group of LED packages 23u is mounted, and a second group of LED packages on a substrate on which wirings for connecting the LED packages to an external power source are formed. 23d) is separated by the second flexible circuit board 22d mounted thereon. As a result, the present invention can increase the number of wirings formed on the flexible circuit boards without inhibiting the slimming of the backlight unit and the liquid crystal display device.

10 and 11 show an LED array 100 according to a second embodiment of the present invention.

10 and 11, the LED array 100 of the present invention includes a first LED array 100u, a second LED array 100d, and a third LED array 100m.

The first LED array 100u includes a first flexible circuit board 22u on which the first group of LED packages 23u are mounted, and a first metal core 21u on which the first flexible circuit board 22u is mounted. do.

Each of the first group of LED packages 23u are side view type LED packages in which light is emitted from the side. The first group of LED packages 23u are mounted on the first flexible circuit board 22u. Wirings for connecting the cathode terminal leads and the anode terminal leads of each of the first group of LED packages 23u to an external power source are formed on the first flexible printed circuit board 22u. The first flexible circuit board 22u may be selected from FPCB, FW, and FC. The spacing between the first group of LED packages 23u is wide enough that two or more LED packages can be placed so that the heat source can be sufficiently dispersed. The first metal core 21u is designed to have a flat plate structure on which the first flexible circuit board 22u is mounted. The first metal core 21u is mounted with a first flexible circuit board 22u on which the LED packages 23u are mounted through an adhesive, an adhesive heat dissipation pad, a screw, and the like. The first metal core 21u is made of a high thermal conductive metal such as aluminum (Al) copper (Cu) to emit heat generated from the first LED packages 23u to the outside. The outer surface of the first metal core 21u may be embossed like a heat sink structure to further enhance the heat dissipation effect. Heat radiated from the first metal core 21u is emitted to the outside through the metal cover member of the liquid crystal display such as the bottom cover.

The second LED array 100d includes a second flexible circuit board 22d on which the second group of LED packages 23d are mounted, and a second metal core 21d on which the second flexible circuit board 22d is mounted. Equipped.

Each of the second group of LED packages 23d is a side view type LED package in which light is emitted from the side. The second group of LED packages 23d are mounted on the second flexible circuit board 22d. Wirings for connecting the cathode terminal leads and the anode terminal leads of each of the second group of LED packages 23d to the external power supply are formed on the second flexible circuit board 22d. The second flexible circuit board 22d may be selected from FPCB, FW, and FC. The spacing between the second group of LED packages 23d is wide enough that two or more LED packages can be arranged so that the heat source can be sufficiently distributed. The second metal core 21d is designed to have a flat plate structure on which the second flexible circuit board 22d is mounted. The second flexible core board 22d on which the second LED packages 23d are mounted is mounted on the second metal core 21d through an adhesive, an adhesive heat dissipation pad, a screw, and the like. The second metal core 21d is made of a high thermal conductive metal such as aluminum (Al) copper (Cu) to emit heat generated from the second LED packages 23d to the outside. The outer surface of the second metal core 21d may be embossed like a heat sink structure to further enhance the heat dissipation effect. Heat radiated from the second metal core 21d is discharged to the outside through the metal cover member of the liquid crystal display such as the bottom cover.

The third LED array 100m includes a third flexible circuit board 22m on which the third group of LED packages 23m are mounted, and a third metal core 21m on which the third flexible circuit board 22m is mounted. Equipped.

Each of the third group of LED packages 23m is a top view type LED package in which light is emitted from the top surface. Each of the third LED packages 23m preferably has a top view type LED package having a thickness width w greater than a side height h such that a light emitting surface of the third LED packages 23m is large. A third group of LED packages 23m is mounted on the third flexible circuit board 22m. Wirings for connecting the cathode terminal leads and the anode terminal leads of each of the third group of LED packages 23m to the external power source are formed on the third flexible circuit board 22m. The third flexible circuit board 22m may be selected from FPCB, FW, and FC. The spacing between the third group of LED packages 23m is wide enough that two or more LED packages can be arranged so that the heat source can be sufficiently dispersed. The third metal core 21m is designed as a flat plate structure on which the third flexible circuit board 22m is mounted, and the thickness thereof is thicker than the first and second metal cores 21u and 21d. An adhesive is applied to the third metal core 21m. The third flexible printed circuit board 22m on which the third LED packages 23m are mounted is mounted through the adhesive heat dissipation pad or the screw. The third metal core 21m is made of a high thermal conductive metal such as aluminum (Al) copper (Cu) to emit heat generated from the third LED packages 23m to the outside. The outer surface of the third metal core 21m may be embossed like a heat sink structure to further increase the heat dissipation effect. Heat radiated from the third metal core 21m is discharged to the outside through the metal cover member of the liquid crystal display such as the bottom cover.

The first to third LED arrays 100u, 100d, and 100m are assembled in the structure as shown in FIG. In the assembled LED array, each of the third group of LED packages 100m is disposed between the first group of LED packages 100u and the third group of LED packages 100d. The first to third metal cores 21u, 21d, and 21m are assembled in a 'c' shape surrounding three surfaces except for the light emitting surface of the LED packages 23u, 23d, and 23m, so that the LED array 100 To increase the heat dissipation effect. Each of the LED packages 23u, 23d, 23m is a white LED package that emits white light with a combination of R LED chip + G LED chip + B LED chip, or a combination of R LED + 2 G LED + B LED chip, or It can be selected as a white LED package that emits white light, including two LED chips generating different colors of light and a silicon layer containing phosphors. In addition, white light may be emitted by combining the R LED package 23u of the first group, the G LED package 23m of the third group, and the B LED package 23d of the second group.

12 is a cross-sectional view illustrating an example in which ends of the first and second metal cores 21u and 21d cover an edge portion of the light guide plate 24 in the edge type backlight unit. As shown in FIG. 12, when the ends of the first and second metal cores 21u and 21d cover the ends of the light guide plate, light leakage between the light guide plate 24 and the LED array 100 may be prevented to increase light efficiency and may be provided at the edge of the display screen. The phenomenon of bright lines can be prevented.

13 is a cross-sectional view illustrating an edge type backlight unit including the LED array 100.

Referring to FIG. 13, the edge type backlight unit of the present invention includes an LED array 100 for irradiating light to the side surface of the light guide plate 24. Optical sheets 134 are disposed between the light guide plate 24 and the liquid crystal display panel 10. The optical sheets 134 may include at least one prism sheet, at least one diffusion sheet, and the like to diffuse light incident from the light guide plate 24 and may be substantially perpendicular to the light incident surface of the liquid crystal display panel 10. To deflect the path of light. The optical sheets 134 may further include a dual brightness enhancement film (DBEF). The guide panel 131 surrounds the sides of the liquid crystal display panel 10 and the edge type backlight unit and supports the liquid crystal display panel 10 between the liquid crystal display panel 10 and the optical sheets 134. The bottom cover 132 surrounds the lower surface of the edge type backlight unit and a portion thereof faces the metal cores 21u, 21d, and 21m of the LED array. The reflective sheet 133 is disposed between the bottom cover 132 and the light guide plate 24. The top case 135 surrounds the side of the liquid crystal display panel 10 and the side of the guide panel 131. Heat emitted from the LED array 100 is discharged to the outside through the metal core (21u, 21d, 21m) and the bottom cover 132.

14 is a cross-sectional view illustrating a direct backlight unit including the LED array 100.

Referring to FIG. 14, the direct type backlight unit of the present invention includes a diffusion plate 145 disposed between the liquid crystal display panel 10 and the LED arrays 100 and optical sheets 146. The LED arrays 100 are disposed under the diffusion plate 145. The guide panel 141 surrounds the sides of the liquid crystal display panel 10 and the direct type backlight unit and supports the liquid crystal display panel 10 between the liquid crystal display panel 10 and the optical sheets 146. The bottom cover 142 surrounds the bottom surface of the direct type backlight unit and faces the metal cores 21u, 21d, and 21m of the LED array 100. The reflective sheet 143 is disposed between the bottom cover 142 and the LED array 100. The top case 145 surrounds the side of the liquid crystal display panel 10 and the side of the guide panel 141. Heat emitted from the LED array 100 is discharged to the outside through the metal core (21u, 21d, 21m) and the bottom cover 142.

Examples of arrangement of the LED packages 23u, 23d, and 23m are not limited to the above-described embodiments, and various modifications may be made without departing from the spirit of the present invention. For example, as shown in FIG. 15, each of the first group of LED packages 23u and the second group of LED packages 23d is continuous by a predetermined number, and the first group of LED packages 23u and the second group are respectively. The LED packages 23u and 23d may be disposed in a structure in which the LED packages 23d of the plurality are alternately arranged.

The metal cores 21u, 21m, and 21d are not limited to the above-described embodiments and various modifications may be made without departing from the spirit of the present invention. For example, as shown in FIG. 16, the sidewalls of each of the first and second metal cores 21u and 21d may be processed in an uneven form, and the first and second metal cores 21u and 21d may be as if teeth of the star are engaged. Similar to the structure, they can be combined into interlocking structures. Ends 21edge extending from the first and second metal cores 21u and 21d toward the light guide plate 24 are extended as shown in FIGS. 17A and 17B, and the gap between the ends 21edge is extended. It can be processed up to the thickness of). 17A and 17B, when the distance between the ends of the first and second metal cores 21u and 21d is narrowed to less than or equal to the thickness of the light guide plate 24, the metal cores 21u and 21d at the time of swinging of the light guide plate 24. ) May serve as a stopper to protect the LED packages 23u and 23d from the impact of the light guide plate 24. The metal cores 21u, 21m, and 21d may be integrated as shown in FIG. 18. A groove is formed at one side of the integrated metal core 21, and at least two flexible circuit boards 22u and 22d are mounted on sidewalls of the groove.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

1 is a block diagram illustrating a circuit configuration and a backlight unit of a liquid crystal display according to an exemplary embodiment of the present invention.

2 is a front view of the LED array according to the first embodiment of the present invention.

3 is a side view of the LED array shown in FIG. 2.

FIG. 4 is a view illustrating an LED package row in a state in which the first and second LED arrays illustrated in FIGS. 2 and 3 are assembled.

FIG. 5 is a view showing the LED array of FIG. 4 applied to an edge type backlight unit.

FIG. 6 is a perspective view illustrating an LED array assembled as shown in FIG. 4.

7A and 7B are diagrams of experimental results comparing heat dissipation effects between a conventional LED array and an LED array according to the present invention when only heat conduction is considered.

8A and 8B are diagrams of experimental results comparing heat dissipation effects between a conventional LED array and an LED array according to the present invention in consideration of thermal conductivity and backside tropical currents.

9 is a view showing a result of comparing the heat conduction and tropical flow as an experimental result comparing the heat radiation effect of the conventional LED array and the LED array of the present invention.

10 is a front view of the LED array according to the second embodiment of the present invention.

FIG. 11 is a side view of the LED array shown in FIG. 10.

FIG. 12 is a view illustrating an LED package row in a state in which the first and second LED arrays illustrated in FIGS. 10 and 11 are assembled.

13 is a cross-sectional view illustrating an example in which an edge type backlight unit is employed in a liquid crystal display according to an exemplary embodiment of the present invention.

14 is a cross-sectional view illustrating an example in which a direct type backlight unit is employed in a liquid crystal display according to an exemplary embodiment of the present invention.

15 is a view showing the arrangement of the LED package according to another embodiment of the present invention.

16 to 18 illustrate metal cores according to various embodiments of the present disclosure.

Description of the Related Art

10 liquid crystal display panel 16 backlight unit

21, 21d, 21u, 21m: Metal core 22d, 22u, 22m: Flexible circuit board

23d, 23u, 23m: LED Package 100: LED Array

Claims (9)

A first LED array comprising a first group of LED packages, a first flexible circuit board on which the first group of LED packages are mounted, and a first metal core on which the first flexible circuit board is mounted; And A second LED array comprising a second group of LED packages, a second flexible circuit board on which the second group of LED packages are mounted, and a second metal core on which the second flexible circuit board is mounted; And the first group of LED packages and the second group of LED packages are alternately arranged. The method of claim 1, In each of the first and second LED arrays, The spacing between the LED packages is greater than one or more LED packages, Each of the first and second metal cores, Has a "L" shaped cross section having a concave portion to which the flexible circuit boards are mounted, The first and second metal cores, It is assembled symmetrically to surround three sides except for the light emitting portion of the LED package, Each of the first and second group of LED packages, A light emitting diode array comprising a side view type LED package for emitting light through a side surface. The method of claim 2, And a third LED array including a third group of LED packages, a third flexible circuit board on which the third group of LED packages are mounted, and a third metal core on which the third flexible circuit board is mounted, Each of the third group of LED packages is disposed between the first group of LED packages and the second group of LED packages, Each of the first metal core, the second metal core and the third metal core has a flat plate structure, The first metal core, the second metal core and the third metal core are assembled in a 'c' shape to surround three surfaces of the LED packages except for the light emitting portion. Array. The method of claim 3, wherein Each of the third group of LED packages, A light emitting diode array comprising a top view type LED package for emitting light through the top surface. A metal core having a groove formed on one side; A first flexible circuit board mounted at one side of the groove and mounted with a first group of LED packages; And A second flexible circuit board mounted on the other side of the groove and mounted with a second group of LED packages; And the first group of LED packages and the second group of LED packages are alternately arranged. A backlight unit including a light emitting diode array; And A liquid crystal display panel for displaying an image by controlling the transmittance of light from the backlight unit by using liquid crystal molecules controlled by an electrical signal; The light emitting diode array, A first LED array comprising a first group of LED packages, a first flexible circuit board on which the first group of LED packages are mounted, and a first metal core on which the first flexible circuit board is mounted; And A second LED array including a second group of LED packages, a second flexible circuit board on which the second group of LED packages are mounted, and a second metal core on which the second flexible circuit board is mounted; And the first group of LED packages and the second group of LED packages are alternately arranged. The method of claim 6, In each of the first and second LED arrays, Wherein the spacing between the LED packages is greater than one or more LED packages. The method of claim 7, wherein The LED array, And a third LED array including a third group of LED packages, a third flexible circuit board on which the third group of LED packages are mounted, and a third metal core on which the third flexible circuit board is mounted, And each of the third group of LED packages is disposed between the first group of LED packages and the second group of LED packages. A backlight unit including a light emitting diode array; And A liquid crystal display panel for displaying an image by controlling the transmittance of light from the backlight unit using liquid crystal molecules controlled by an electrical signal; The light emitting diode array, A metal core having a groove formed on one side; A first flexible circuit board mounted at one side of the groove and mounted with a first group of LED packages; And A second flexible circuit board mounted on the other side of the groove and mounted with a second group of LED packages; And the first group of LED packages and the second group of LED packages are alternately arranged.

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