Backlight unit and display device including the same

Abstract

A backlight unit and a display device including the backlight unit are provided. The backlight unit includes: a substrate including a first area and a second area in which a plurality of light source blocks are arranged; a light source driver arranged on at least one side of the substrate and connected to the plurality of light source blocks in the first area and the plurality of light source blocks in the second area via first sensing lines and second sensing lines, respectively, wherein the first sensing lines connected to the plurality of light source blocks in the first area have a first resistance value, and the second sensing lines connected to the plurality of light source blocks in the second area have a second resistance value.

Description

Technical Field

[0001] The present disclosure relates to a backlight unit and a display device including the backlight unit. Background Art

[0002] With the development of the information society, the demand for display devices for displaying images is increasing in various forms. For example, display devices are being applied to various electronic devices such as smart phones, digital cameras, notebook computers, navigation devices, and smart TVs. The display device may be a flat panel display device such as a liquid crystal display device, a field emission display device, and an organic light emitting display device.

[0003] Among them, a liquid crystal display device includes an array substrate including a thin film transistor, an upper substrate including a color filter and / or a black matrix, and a liquid crystal layer disposed between the array substrate and the upper substrate. The liquid crystal display device is a device that displays an image by adjusting the arrangement state of the liquid crystal layer according to an electric field applied between two electrodes in a pixel area and adjusting the transmittance of light according to the arrangement state. Summary of the invention

[0004] Technical issues

[0005] Aspects of the present disclosure provide a backlight unit and a display device including the same, which can minimize power loss and heat generation of a sensing line or a light source driver.

[0006] However, aspects of the present disclosure are not limited to the aspects set forth herein. The above and other aspects of the present disclosure will become more apparent to those skilled in the art to which the present disclosure pertains by referring to the detailed description of the present disclosure given below.

[0007] Technical Solution

[0008] According to a disclosed embodiment, a backlight unit includes: a substrate including a first area and a second area, each of the first area and the second area having a plurality of light source blocks; and a light source driver disposed on at least one side of the substrate and connected to each of the plurality of light source blocks in the first area and the second area through each of a first sensing line and a second sensing line. A first sensing line connected to each of the plurality of light source blocks in the first area has a first resistance value, and a second sensing line connected to each of the plurality of light source blocks in the second area has a second resistance value.

[0009] Each of the first and second sensing lines may have different cross-sectional areas according to a length of each of the first and second sensing lines.

[0010] Each of the first sensing lines may have a cross-sectional area proportional to the distance between each of the multiple light source blocks in the first area and the light source driver, and each of the second sensing lines may have a cross-sectional area proportional to the distance between each of the multiple light source blocks in the second area and the light source driver.

[0011] The first region may be closer to the light source driver than the second region, and the first resistance value may be smaller than the second resistance value.

[0012] The backlight unit may further include a power supply unit which supplies a first driving voltage to the plurality of light source blocks of the first area and supplies a second driving voltage to the plurality of light source blocks of the second area.

[0013] The first area may be closer to the light source driver than the second area, and the first driving voltage may be lower than the second driving voltage.

[0014] A difference between the first driving voltage and the second driving voltage may correspond to a difference between a voltage applied to the first sensing line and a voltage applied to the second sensing line.

[0015] The power supply unit may generate the first driving voltage and the second driving voltage based on each of the first feedback voltage and the second feedback voltage received from the light source driver.

[0016] The power supply unit may supply each of the first driving voltage and the second driving voltage through each of the first power line and the second power line, and the first power line and the second power line may have the same resistance value.

[0017] The substrate may further include a third region having a plurality of light source blocks, and the light source driver may be connected to the plurality of light source blocks of the third region through a third sensing line having a third resistance value.

[0018] The third sensing line may have different cross-sectional areas according to each of the lengths of the third sensing line.

[0019] The backlight unit may further include a power supply unit which supplies first to third driving voltages to the plurality of light source blocks in the first to third areas, respectively, based on first to third feedback voltages received from the light source driver.

[0020] The light source driver may include a first light source driver disposed adjacent to the first area and connected to the plurality of light source blocks of the first area; and a second light source driver disposed adjacent to the second area and connected to the plurality of light source blocks of the second area.

[0021] The backlight unit may further include: a power supply unit supplying the same driving voltage to the plurality of light source blocks in the first area and the plurality of light source blocks in the second area. The first resistance value and the second resistance value may be equal to each other.

[0022] Each of the first and second sensing lines may have different cross-sectional areas according to the length of each of the first and second sensing lines.

[0023] The first sensing line and the second sensing line may have the same cross-sectional area and length.

[0024] Each of the plurality of light source blocks may include at least one small light emitting diode (LED) or micro LED.

[0025] According to a disclosed embodiment, a backlight unit includes: a substrate including a plurality of light source blocks; a power supply unit supplying a driving voltage to the plurality of light source blocks; and a light source driver disposed on one side of the substrate and connected to the substrate through a sensing line connected to the plurality of light source blocks. The power supply unit supplies the same driving voltage to the plurality of light source blocks, and the sensing line connected to each of the plurality of light source blocks has the same resistance value.

[0026] The sensing lines may have different cross-sectional areas according to the length of each of the sensing lines.

[0027] The sensing lines may have the same cross-sectional area and length.

[0028] According to a disclosed embodiment, a display device includes: a display panel that displays an image; and a backlight unit that irradiates light to the display panel. The backlight unit includes: a substrate that includes a first area and a second area, each of the first area and the second area having a plurality of light source blocks; and a light source driver that is disposed on at least one side of the substrate and is connected to each of the plurality of light source blocks in the first area and the second area through each of the first sensing lines and the second sensing lines. The first sensing line connected to each of the plurality of light source blocks in the first area has a first resistance value, and the second sensing line connected to each of the plurality of light source blocks in the second area has a second resistance value.

[0029] Additional details of the disclosure are included in the detailed description and accompanying drawings.

[0030] Beneficial Effects

[0031] In a backlight unit and a display device including the backlight unit according to an embodiment, the sensing lines connected to the plurality of light source blocks in each of the plurality of regions of the substrate may have different cross-sectional areas according to the lengths of the sensing lines. Therefore, the sensing lines connected to the plurality of light source blocks in one region may have the same resistance value, and the magnitude of the driving voltage applied to the light source blocks may be reduced. Therefore, this may minimize the power loss and heat generation of the sensing lines and the light source driver, and improve the efficiency of the backlight unit.

[0032] In the backlight unit and the display device including the backlight unit according to the embodiment, the sensing lines connected to the plurality of light source blocks in each of the plurality of regions of the substrate may have the same cross-sectional area and length. Therefore, the sensing lines connected to the plurality of light source blocks in one region may have the same resistance value. Therefore, this may minimize the power loss and heat generation of the sensing lines and the light source driver, and improve the efficiency of the backlight unit.

[0033] However, the effects of the present disclosure are not limited to the above-mentioned effects, and various other effects are included in the present specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is an exploded perspective view of a display device according to an embodiment;

[0035] Figure 2 is based on Figure 1 A plan view of a backlight unit of the first embodiment in a display device shown in FIG.

[0036] Figure 3 It is shown Figure 2 An example diagram of area AA and a connection relationship in area AA;

[0037] Figure 4 It is used to explain Figure 3 An example diagram of the resistance values ​​of the sensing wires shown in ;

[0038] Figure 5 yes Figure 2 A circuit diagram of an example of a backlight unit shown in ;

[0039] Figure 6 It is shown Figure 2 A circuit diagram of a voltage drop of a backlight unit shown in;

[0040] Figure 7 is based on Figure 1 A plan view of a backlight unit of a second embodiment of a display device shown in FIG.

[0041] Figure 8 It is shown Figure 7 An example diagram of area AB and connection relationships in area AB;

[0042] Fig. 9 yes Figure 7 A circuit diagram of an example of a backlight unit shown in ;

[0043] Fig.10 It is shown Figure 7 A circuit diagram of a voltage drop of a backlight unit shown in;

[0044] Fig.11 is based on Figure 1 A plan view of a backlight unit of a third embodiment of a display device shown in FIG.

[0045] Fig.12 It is shown Fig.11 An example diagram of region AC and connection relationship in region AC;

[0046] Fig.13 It is shown Fig.11 Another example diagram of region AC and connection relationship in region AC;

[0047] Fig.14 yes Fig.11 A circuit diagram of an example of a backlight unit shown in ;

[0048] Fig.15 It is shown Fig.11 A circuit diagram of a voltage drop of a backlight unit shown in;

[0049] Fig.16 is an exploded perspective view of a display device according to an embodiment;

[0050] Fig.17 is based on Fig.16 A plan view of a backlight unit of a fourth embodiment of a display device shown in FIG.

[0051] Fig.18 It is shown Fig.17 An example diagram of regions AD and connection relationships in regions AD; and

[0052] Fig.19 It is shown Fig.17 Another example diagram of areas AD and the connection relationship in areas AD. DETAILED DESCRIPTION

[0053] The invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. However, the invention may be implemented in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art.

[0054] It will also be understood that when a layer is referred to as being “on” another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. Throughout the specification, the same reference numerals refer to the same components.

[0055] It will be understood that although the terms "first", "second", etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the teachings of the invention, the first element discussed below may be referred to as the second element. Similarly, the second element may also be referred to as the first element.

[0056] The features of the various embodiments of the present invention may be combined partially or completely or in combination with each other, various interlocks and drives may be technically feasible, and the various embodiments may be implemented independently of each other and may also be implemented in association with each other.

[0057] Hereinafter, embodiments will be described with reference to the accompanying drawings.

[0058] Figure 1 is an exploded perspective view of a display device according to an embodiment.

[0059] In this specification, "above", "top" and "upper surface" refer to the upward direction (i.e., the Z-axis direction) of the display device 10, and "below", "bottom" and "lower surface" refer to the downward direction (i.e., the direction opposite to the Z-axis direction) of the display device 10. In addition, "left", "right", "upper" and "lower surface" refer to directions when the display device 10 is viewed in a plan view. For example, "left" refers to the direction opposite to the X-axis direction, "right" refers to the X-axis direction, "upper" refers to the Y-axis direction, and "lower" refers to the direction opposite to the Y-axis direction.

[0060] Reference Figure 1 , the display device 10 according to the embodiment includes a backlight unit 100 , a diffusion plate 200 , an optical sheet unit 300 , a display panel 400 , and a case member 500 .

[0061] The backlight unit 100 may include a substrate 110 , a power supply unit 120 , a light source driver 130 , a printed circuit board 140 , and a plurality of flexible films 150 .

[0062] The substrate 110 may include a plurality of light source blocks LB, each of which includes at least one light emitting diode (LED), a mini-LED, or a micro-LED. For example, a mini-LED may be a small LED whose light source chip has a size of 100 μm to 500 μm, and a light source chip of a micro-LED may have a size of 5 μm to 10 μm, but the present disclosure is not necessarily limited thereto. The light source blocks LB may be arranged on the substrate 110 to correspond to the display area of ​​the display panel 400. Since the light source blocks LB include mini-LEDs or micro-LEDs as described above, they may have a thickness similar to that in an edge-type backlight structure (edge ​​type backlight structure, or referred to as an edge-type backlight unit, edge-type backlight unit) even in a direct type backlight structure, may have a high dynamic range (HDR) that cannot be implemented (realized) in an edge-type backlight structure, and may easily perform local dimming.

[0063] The power supply unit 120 may be mounted on a printed circuit board 140 disposed on at least one side of the substrate 110 to supply a driving voltage to the light source block LB. Specifically, the power supply unit 120 may receive a feedback voltage from the light source driver 130, generate a driving voltage based on the feedback voltage, and supply the driving voltage to the light source block LB. For example, each of the power supply units 120 may include at least one inductor, a capacitor, a diode, a transistor, an integrated circuit, and a voltage source, but the present disclosure is not necessarily limited thereto.

[0064] In addition, the power supply unit 120 may supply a driving voltage to the light source block LB through a power supply line, and the power supply line may be connected from the power supply unit 120 to the light source block LB via the flexible film 150 .

[0065] The light source driver 130 may be mounted on a printed circuit board 140 disposed on at least one side of the substrate 110 to drive the light source block LB. Specifically, the light source driver 130 may control the current flowing through the light source block LB by controlling a switching transistor connected in series with the light source block LB. For example, the light source driver 130 may independently control each of the light source blocks LB to easily perform local dimming, improve contrast, and reduce power consumed by the light source block LB.

[0066] Furthermore, the light source driver 130 may be connected to the light source block LB through the sensing lines, and the sensing lines may be connected from the light source block LB to the light source driver 130 via the flexible film 150. For example, at least some of the sensing lines may be finely patterned and highly densely arranged on the substrate 110.

[0067] The power supply unit 120 and the light source driver 130 may be mounted on the printed circuit board 140. In addition, a power line connected to the power supply unit 120 and a sensing line connected to the light source driver 130 may also be mounted on the printed circuit board 140. According to an example, the printed circuit board 140 may be bent together with the flexible film 150 to reduce the border area of ​​the display device 10. For example, the printed circuit board 140 may be implemented as a single substrate on which all the power supply units 120 and the light source drivers 130 may be mounted, or may be implemented as a plurality of substrates, and a plurality of groups divided by the power supply units 120 and the light source drivers 130 may be respectively mounted on the plurality of substrates. Here, according to the arrangement structure of the power supply unit 120 and the light source driver 130 and the method of driving the light source block LB, the printed circuit board 140 may be changed into various configurations.

[0068] Each of the flexible films 150 may connect the printed circuit board 140 to the substrate 110. Specifically, the terminal disposed on one side of each of the flexible films 150 may be attached (attached) to the printed circuit board 140 by a film attaching process (film attaching process, or referred to as a film attaching process), and the terminal disposed on the other side of each of the flexible films 150 may be attached to the substrate 110 by a film attaching process. According to an example, each of the flexible films 150 may be bent to reduce a bezel area of ​​the display device 10. For example, each of the flexible films 150 may be formed of a tape carrier package or a flexible chip on board or a chip on film.

[0069] The diffusion plate (diffuser plate) 200 may be disposed on the front surface of the backlight unit 100. Specifically, the diffusion plate 200 may be supported by the upper surface of the bottom housing 510, and the backlight unit 100 may be disposed on the bottom surface of the bottom housing 510, thereby forming a predetermined space between the diffusion plate 200 and the backlight unit 100. According to an embodiment, the diffusion plate 200 may be made of a material having a higher light diffusion rate than the optical sheet unit 300. As described above, since the diffusion plate 200 is interposed between the backlight unit 100 and the optical sheet unit 300, the diffusion of light emitted from the light source block LB may be improved.

[0070] The optical sheet unit 300 may be disposed on the rear surface of the display panel 400. For example, the optical sheet unit 300 may be interposed between the diffusion plate 200 and the display panel 400 to improve the brightness characteristics of the light emitted from the light source block LB. According to an example, the optical sheet unit 300 may be a composite optical sheet having a function of diffusing incident light and a function of converging diffused light.

[0071] According to an example, the optical sheet unit 300 may be attached to the rear surface of the display panel 400 by a lamination process using a transparent bonding member as a medium. Here, the transparent bonding member may be an optically clear adhesive (OCA), an optically clear resin (OCR), a porous OCA, or a porous OCR. Optionally, when the optical sheet unit 300 is formed of one composite optical sheet, the optical sheet unit 300 may further include a plurality of light-condensing patterns (including a prism pattern or a lens pattern).

[0072] The display panel 400 may include a lower substrate 410 , an upper substrate 420 , a plurality of flexible films 430 , a plurality of source driving circuits 440 , a source circuit board 450 , and a timing controller 460 .

[0073] The lower substrate 410 and the upper substrate 420 may be made of glass or plastic. The size of the lower substrate 410 may be larger than that of the upper substrate 420. Therefore, the flexible film 430 may be attached to the edge of the upper surface of the lower substrate 410 that is not covered by the upper substrate 420 by a film attaching process. Here, the upper surface of the lower substrate 410 may be a surface facing the upper substrate 420.

[0074] Signal lines and pixels may be disposed on the upper surface of the lower substrate 410 of the display panel 400. For example, the signal lines may include data lines and gate lines crossing each other, common voltage lines for supplying a common voltage to a common electrode, and scan control lines for supplying a control signal to a gate driving circuit.

[0075] The black matrix and the color filter may be disposed on the lower surface of the upper substrate 420 of the display panel 400. Here, the lower surface of the upper substrate 420 may be a surface facing the lower substrate 410. For another example, when the display panel 400 is formed using a color filter on TFT array (COT), the black matrix and the color filter may be disposed on the upper surface of the lower substrate 410.

[0076] The common electrode may be disposed on the lower surface of the upper substrate 420 in a vertical electric field driving method such as a twisted nematic (TN) mode and a vertical alignment (VA) mode, and may be disposed on the upper surface of the lower substrate 410 in a horizontal electric field driving method such as an in-plane switching (IPS) mode and a fringefield switching (FFS) mode. In addition, an alignment layer for setting a pretilt angle of liquid crystal may be formed on the upper surface of the lower substrate 410 and the lower surface of the upper substrate 420 of the display panel 400.

[0077] The lower polarizing plate may be attached to the lower surface of the lower substrate 410 of the display panel 400. A transparent electrode may be formed on the entire upper surface of the upper substrate 420 of the display panel 400, and the upper polarizing plate may be attached to the transparent electrode. Here, the transparent electrode may be connected to the ground to discharge static electricity generated in the upper substrate 420 of the display panel 400.

[0078] The display panel 400 may further include a liquid crystal layer (not shown) disposed between the lower substrate 410 and the upper substrate 420. The liquid crystal layer may be driven by an electric field generated by a potential difference between a data voltage supplied to each pixel electrode and a common voltage supplied to a common electrode. Thus, the transmittance of light incident from the backlight unit 100 may be adjusted.

[0079] Each of the flexible films 430 may connect the source circuit board 450 and the lower substrate 410. Specifically, the input terminal disposed on one side of each of the flexible films 430 may be attached to the source circuit board 450 by a film attaching process, and the output terminal disposed on the other side of each of the flexible films 430 may be attached to the pad portion of the lower substrate 410 by a film attaching process. According to an embodiment, each of the flexible films 430 may be bent to reduce a bezel area of ​​the display device 10. For example, each of the flexible films 430 may be formed of a tape carrier package or a chip on a flexible board or a chip on a film.

[0080] A plurality of source driving circuits 440 may be individually mounted on the plurality of flexible films 430. Each of the source driving circuits 440 may receive pixel data and a data control signal from the timing controller 460, convert the pixel data into an analog data signal for each pixel according to the data control signal, and supply the analog data signal to a corresponding data line.

[0081] The source circuit board 450 may support the timing controller 460 and transmit the signal and power output from the timing controller 460. The source circuit board 450 may provide the source driving circuit 440 and the scan driver (not shown) with the signal and driving power supplied from the timing controller 460 to display an image in each pixel. To this end, signal transmission wiring and various power wirings may be provided on the source circuit board 450. For example, one or more source circuit boards 450 may be provided according to the number of flexible films 430.

[0082] The timing controller 460 may be mounted on the source circuit board 450, and may receive image data and a timing synchronization signal provided from the display driving system through a user connector provided on the source circuit board 450. The timing controller 460 may generate pixel data by aligning the image data to be suitable for the pixel arrangement structure based on the timing synchronization signal, and provide the generated pixel data to the corresponding source driving circuit 440. In addition, the timing controller 460 may generate each of a data control signal and a scan control signal based on the timing synchronization signal, control the driving timing of each of the source driving circuits 440 through the data control signal, and control the driving timing of the scan driver through the scan control signal. Here, the scan control signal may be supplied to the scan driver through the first flexible film or / and the last flexible film and the non-display area among the flexible films 430.

[0083] The housing member 500 may include a bottom housing 510 , a support frame 520 , and a top housing 530 .

[0084] The bottom housing 510 may be manufactured as a quadrilateral metal frame to accommodate the backlight unit 100. Specifically, the backlight unit 100 may be disposed on the bottom surface of the bottom housing 510, and the diffusion plate 200 may be disposed on the upper surface of the bottom housing 510, thereby forming a predetermined space between the backlight unit 100 and the diffusion plate 200. In addition, the bottom housing 510 may be manufactured using a high-strength steel plate to support and protect the backlight unit 100. For example, the bottom housing 510 may be manufactured using electrogalvanized steel plate (EGI), stainless steel (SUS), aluminum zinc plated (SGLC), aluminum plated steel plate (also known as ALCOSTA), tin plated steel plate (SPTE), etc.

[0085] The support frame 520 may support the lower surface of the lower substrate 410 of the display panel 400. The support frame 520 may be coupled to the bottom case 510 by a coupling member. For example, the support frame 520 may be made of the same material as the bottom case 510, but the present disclosure is not necessarily limited thereto.

[0086] According to an example, the support frame 520 may be integrated with the bottom case 510. According to another example, the support frame 520 may be omitted, and the top case 530 may be directly coupled to the bottom case 510.

[0087] The top housing 530 may cover the edge of the display panel 400, the upper and side surfaces of the support frame 520, and the side surface of the bottom housing 510. For example, the top housing 530 may be made of the same material as the bottom housing 510 or the support frame 520, but the present disclosure is not necessarily limited thereto. The top housing 530 may be coupled to the support frame 520 by a coupling member such as a hook or a screw.

[0088] Figure 2 is based on Figure 1 1 is a plan view of a backlight unit of a first embodiment in a display device shown in FIG. Figure 3 It is shown Figure 2 An example diagram of area AA and the connection relationship within area AA. Figure 4 It is used to explain Figure 3 An example diagram of the resistance values ​​of the sense lines shown in FIG.

[0089] Reference Figures 2 to 4 , the substrate 110 may include a light emitting area LA consisting of a plurality of light source blocks LB. In addition, the light emitting area LA may include a first area A1 including a plurality of light source blocks LBa and a second area A2 including a plurality of light source blocks LBb. According to an example, the first area A1 may be closer to the power supply unit 120 and the light source driver 130 mounted on the printed circuit board 140 than the second area A2. In other words, the distance between the light source block LBa of the first area A1 and the light source driver 130 may be smaller than the distance between the light source block LBb of the second area A2 and the light source driver 130. Therefore, the length of each of the first sensing lines SLa connected between the light source block LBa of the first area A1 and the first light source driver 131 may be smaller than the length of each of the second sensing lines SLb connected between the light source block LBb of the second area A2 and the second light source driver 132.

[0090] Each of the power supply units 120 may include a first power supply unit 121 and a second power supply unit 122 , and each of the light source drivers 130 may include a first light source driver 131 and a second light source driver 132 .

[0091] The first power supply unit 121 may supply the first driving voltage VLED1 to the light source block LBa of the first area A1 through the first power line VL1, and the second power supply unit 122 may supply the second driving voltage VLED2 to the light source block LBb of the second area A2 through the second power line VL2. Specifically, the first power supply unit 121 may receive the first feedback voltage FB1 from the first light source driver 131, and generate the first driving voltage VLED1 based on the first feedback voltage FB1. The second power supply unit 122 may receive the second feedback voltage FB2 from the second light source driver 132, and generate the second driving voltage VLED2 based on the second feedback voltage FB2.

[0092] According to an example, the first power lines VL1 respectively connected to the first to n-th light source blocks LB1 to LB(n) may have the same resistance value, and the second power lines VL2 respectively connected to the n+1-th to 2n-th light source blocks LB(n+1) may have the same resistance value. Therefore, the backlight unit 100 according to the present disclosure may minimize the power consumed in the first and second power lines VL1 and VL2.

[0093] The first light source driver 131 may control the current flowing through the light source block LBa of the first area A1 through the first sensing line SLa, and the second light source driver 132 may control the current flowing through the light source block LBb of the second area A2 through the second sensing line SLb.

[0094] According to an example, the number of light source blocks LBa of the first area A1 may be equal to the number of light source blocks LBb of the second area A2, but is not necessarily limited thereto. For example, the first area A1 may include the first light source block LB1 to the nth light source block LB(n) (where n is a natural number of 2 or more), and the second area A2 may include the n+1th light source block LB(n+1) to the 2nth light source block LB(2n). In addition, the first light source block LB1 to the nth light source block LB(n) may be connected to the first light source driver 131 through the first sensing lines SL1 to SL(n), respectively, and the n+1th light source block LB(n+1) to the 2nth light source block LB(2n) may be connected to the second light source driver 132 through the second sensing lines SL(n+1) to SL(2n), respectively. That is, the length of each of the first sensing lines SL1 to SL(n) may be smaller than the length of each of the second sensing lines SL(n+1) to SL(2n).

[0095] For example, the first sensing line SL1 connected to the first light source block LB1 may be shorter than the first sensing line SL2 connected to the second light source block LB2. In this way, the first sensing lines SL1 to SL(n) may be relatively long or relatively short, respectively, according to the distance between the first light source block LB1 to the nth light source block LB(n) and the first light source driver 131. In addition, the second sensing line SL(n+1) connected to the n+1th light source block LB(n+1) may be longer than each of the first sensing lines SL1 to SL(n), and may be shorter than the second sensing line SL(n+2) connected to the n+2nd light source block LB(n+2). In this way, the second sensing lines SL(n+1) to SL(2n) may be relatively long or relatively short, respectively, according to the distance between the n+1th light source block LB(n+1) to the 2nth light source block LB(2n) and the second light source driver 132.

[0096] exist Figure 4, one light source block LB(k) (where k is a natural number from 1 to 2n) among the first to 2nth light source blocks LB1 to LB(2n) connected to one sensing line SL(k) of the light source driver 130 may have a self-resistance as shown in the following Equation 1:

[0097] [Equation 1]

[0098]

[0099] In Equation 1, R is the self-resistance of the line (or wiring), p is the specific resistance according to the material of the line, l is the length of the line, and a is the cross-sectional area of ​​the line. Therefore, the resistance of the sensing line SL(k) may decrease as the cross-sectional area a(k) increases, and may increase as the length l(k) increases.

[0100] The first sensing lines SL1 to SL(n) may have the same first resistance value. According to an example, the first sensing lines SL1 to SL(n) may have different lengths according to the positions of the first light source block LB1 to the nth light source block LB(n), respectively. Since the first sensing lines SL1 to SL(n) have different cross-sectional areas according to the lengths of the first sensing lines SL1 to SL(n), respectively, they may have the same first resistance value. In addition, since the first sensing lines SL1 to SL(n) respectively have cross-sectional areas proportional to the distances between the light source blocks LBa of the first area A1 and the first light source driver 131, they may have the same first resistance value.

[0101] The second sensing lines SL(n+1) to SL(2n) may have the same second resistance value. According to an example, the second sensing lines SL(n+1) to SL(2n) may have different lengths according to the positions of the n+1th light source blocks LB(n+1) to the 2nth light source blocks LB(2n). Since the second sensing lines SL(n+1) to SL(2n) have different cross-sectional areas according to the lengths of the second sensing lines SL(n+1) to SL(2n), they may have the same second resistance value. In addition, since the second sensing lines SL(n+1) to SL(2n) respectively have cross-sectional areas proportional to the distance between the light source blocks LBb of the second area A2 and the second light source driver 132, they may have the same second resistance value.

[0102] Since the first sensing lines SL1 to SL(n) have the same first resistance value as described above, the first driving voltage VLED1 provided from the first power supply unit 121 may be reduced to the same voltage value in each of the first to n-th light source blocks LB1 to LB(n), each of the first sensing lines SL1 to SL(n), and the first light source driver 131. For example, the voltage reduced in each of the first light source block LB1, the first sensing line SL1 connected to the first light source block LB1, and the first light source driver 131 may be the same as the voltage reduced in each of the n-th light source block LB(n), the first sensing line SL(n) connected to the n-th light source block LB(n), and the first light source driver 131.

[0103] In addition, since the second sensing lines SL(n+1) to SL(2n) have the same second resistance value, the second driving voltage VLED2 provided from the second power supply unit 122 may be reduced to the same voltage value in each of the n+1th light source block LB(n+1) to the 2nth light source block LB(2n), each of the second sensing lines SL(n+1) to SL(2n), and the second light source driver 132. For example, the voltage reduced in each of the n+1th light source block LB(n+1), the second sensing line SL(n+1) connected to the n+1th light source block LB(n+1), and the second light source driver 132 may be the same as the voltage reduced in each of the 2nth light source block LB(2n), the second sensing line SL(2n) connected to the 2nth light source block LB(2n), and the second light source driver 132.

[0104] If a plurality of sensing lines have different resistance values ​​and the same driving voltage is applied to a plurality of light source blocks, different voltages can be lowered in the plurality of sensing lines, respectively. Here, a relatively high voltage drop occurs in some sensing lines with relatively high resistance values, and the power consumption in these sensing lines increases. In addition, a relatively low voltage drop occurs in some other sensing lines with relatively low resistance values, and a relatively high voltage drop occurs in the light source drivers connected to these sensing lines. Therefore, the light source driver in which a high voltage drop occurs generates heat (generates heat), thereby deteriorating the efficiency of the backlight unit.

[0105] Therefore, in order to solve the above problem, in the backlight unit 100 according to the present disclosure, the first sensing lines SL1 to SL(n) may have the same first resistance value, and the second sensing lines SL(n+1) to SL(2n) may have the same second resistance value. Here, the second sensing lines SL(n+1) to SL(2n) may be longer than the first sensing lines SL1 to SL(n), respectively, and the second resistance value may be higher than the first resistance value. In addition, the first power supply unit 121 may supply the first driving voltage VLED1 to each of the first light source blocks LB1 to the nth light source blocks LB(n) respectively connected to the first sensing lines SL1 to SL(n), and the second power supply unit 122 may supply the second driving voltage VLED2 higher than the first driving voltage VLED1 to each of the n+1th light source blocks LB(n+1) to the 2nth light source blocks LB(2n) respectively connected to the second sensing lines SL(n+1) to SL(2n). Therefore, in the backlight unit 100 according to the present disclosure, the power consumed in the first sensing lines SL1 to SL(n) and the second sensing lines SL(n+1) to SL(2n) can be minimized, and the efficiency of the backlight unit 100 can be improved by preventing the first light source driver 131 and the second light source driver 132 from generating heat.

[0106] Figure 5 yes Figure 2 A circuit diagram of an example of a backlight unit is shown in FIG.

[0107] Reference Figure 5, the first power supply unit 121 may output a first driving voltage VLED1 by increasing (boosting) a direct current (DC) input voltage VIN. According to an example, the first power supply unit 121 may include a driving voltage controller (DC-DC driver). The driving voltage controller (DC-DC driver) may turn on the first transistor T1 in response to a first feedback voltage FB1 received from the first light source driver 131 (LED driver). Here, the driving voltage controller (DC-DC driver) may determine the magnitude of the first driving voltage VLED1 by adjusting the turn-on time of the first transistor T1 based on the first feedback voltage FB1. For example, when a relatively low first feedback voltage FB1 is received, the driving voltage controller (DC-DC driver) may increase the magnitude of the first driving voltage VLED1 by increasing the turn-on time of the first transistor T1. In addition, when a relatively high first feedback voltage FB1 is received, the driving voltage controller (DC-DC driver) may reduce the magnitude of the first driving voltage VLED1 by reducing the turn-on time of the first transistor T1. The first driving voltage VLED1 thus generated may be supplied in parallel to the light source blocks LBa disposed in the first area A1. In addition, the first driving voltage VLED1 may be lowered by each of the first to n-th light source blocks LB1 to LB(n)(LBa), each of the first sensing lines SLa, and the first light source driver 131 .

[0108] The second power supply unit 122 may output a second driving voltage VLED2 by increasing the DC input voltage VIN. According to an example, the second power supply unit 122 may include a driving voltage controller (DC-DC driver). The driving voltage controller (DC-DC driver) may turn on the first transistor T1 in response to the second feedback voltage FB2 received from the second light source driver 132 (LED driver). Here, the driving voltage controller (DC-DC driver) may determine the magnitude of the second driving voltage VLED2 by adjusting the on-time of the first transistor T1 based on the second feedback voltage FB2. For example, when receiving a relatively low second feedback voltage FB2, the driving voltage controller (DC-DC driver) may increase the magnitude of the second driving voltage VLED2 by increasing the on-time of the first transistor T1. In addition, when receiving a relatively high second feedback voltage FB2, the driving voltage controller (DC-DC driver) may reduce the magnitude of the second driving voltage VLED2 by reducing the on-time of the first transistor T1. The second driving voltage VLED2 thus generated may be supplied in parallel to the light source block LBb disposed in the second area A2. In addition, the second driving voltage VLED2 may be lowered by each of the n+1th to 2nth light source blocks LB(n+1) to LB(2n)(LBb), each of the second sensing lines SLb, and the second light source driver 132 .

[0109] Figure 6 It is shown Figure 2 Circuit diagram of the voltage drop of the backlight unit shown in FIG.

[0110] Reference Figure 6 , the first driving voltage VLED1 can be reduced by each of the first light source block LB1 to the nth light source block LB(n)(LBa), each of the first sensing lines SLa, and the first light source driver 131. Specifically, the first light source driver 131 may include a second transistor T2 and an amplifier AMP connected to the gate electrode of the second transistor T2. The first terminal of the amplifier AMP may receive a reference voltage VREF, the second terminal of the amplifier AMP may be connected to the source electrode of the second transistor T2, and the output terminal of the amplifier AMP may be connected to the gate electrode of the second transistor T2. Therefore, the first light source driver 131 may control the conduction of the second transistor T2 so that a current I of a specific size flows through each of the first light source block LB1 to the nth light source block LB(n)(LBa), each of the first sensing lines SLa, and the first light source driver 131. In this way, the first light source driver 131 may be used as a current source.

[0111] The second driving voltage VLED2 may be reduced by each of the n+1th light source block LB(n+1) to the 2nth light source block LB(2n)(LBb), each of the second sensing lines SLb, and the second light source driver 132. Specifically, the second light source driver 132 may include a second transistor T2 and an amplifier AMP connected to a gate electrode of the second transistor T2. The second light source driver 132 may control the conduction of the second transistor T2 through the amplifier AMP so that a current I of a specific size flows through each of the n+1th light source block LB(n+1) to the 2nth light source block LB(2n)(LBb), each of the second sensing lines SLb, and the second light source driver 132. In this way, the second light source driver 132 may be used as a current source.

[0112] For example, the first driving voltage VLED1 may be reduced by the voltage VLB applied to each of the first to n-th light source blocks LB1 to LB(n)(LBa), the voltage I×R1 applied to the first sensing line SLa, the voltage VT applied to the second transistor T2, and the voltage I×RL applied to the load resistor RL (VLED1=VLB+I×R1+VT+I×RL). In this way, the first driving voltage VLED1 supplied in parallel to the first to n-th light source blocks LB1 to LB(n)(LBa) may be reduced to the same size in all the first sensing lines SLa.

[0113] In addition, the second driving voltage VLED2 can be reduced by the voltage VLB applied to each of the n+1th light source block LB(n+1) to the 2nth light source block LB(2n)(LBb), the voltage I×R2 applied to the second sensing line SLb, the voltage VT applied to the second transistor T2, and the voltage I×RL applied to the load resistor RL (VLED2=VLB+I×R2+VT+I×RL). In this way, the second driving voltage VLED2 supplied in parallel to the n+1th light source block LB(n+1) to the 2nth light source block LB(2n)(LBb) can be reduced to the same size in all the second sensing lines SLb.

[0114] Therefore, the difference between the first driving voltage VLED1 and the second driving voltage VLED2 may correspond to the difference between the voltage I×R1 applied to the first sensing line SLa and the voltage I×R2 applied to the second sensing line SLb (VLED2-VLED1=I×R2-I×R1).

[0115] As described above, since the first area A1 of the substrate 110 is set closer to the power supply unit 120 and the light source driver 130 than the second area A2, the first sensing lines SL1 to SL(n) can have the same first resistance value R1, the second sensing lines SL(n+1) to SL(2n) can have the same second resistance value R2, and the first resistance value R1 can be designed to be smaller than the second resistance value R2.

[0116] Therefore, the first power supply unit 121 can supply the first driving voltage VLED1 which is smaller than the second driving voltage VLED2 to the first light source block LB1 to the nth light source block LB(n) respectively connected to the first sensing lines SL1 to SL(n) having the first resistance value R1, thereby minimizing the power consumed in the first sensing lines SL1 to SL(n) and preventing the first light source driver 131 from heating.

[0117] Similarly, the second power supply unit 122 can supply the second driving voltage VLED2 to each of the n+1th light source blocks LB(n+1) to the 2nth light source blocks LB(2n) respectively connected to the second sensing lines SL(n+1) to SL(2n) having the second resistance values ​​R2, thereby minimizing the power consumed in the second sensing lines SL(n+1) to SL(2n) and preventing heating of the second light source driver 132.

[0118] Figure 7 is based on Figure 1 2 is a plan view of a backlight unit according to a second embodiment of the display device shown in FIG. Figure 8 It is shown Figure 7 FIG. 1 is an example diagram of a region AB and a connection relationship in the region AB. Elements that are the same as those described above will be briefly described or not described.

[0119] Reference Figure 7 and Figure 8 , the substrate 110 may include a light emitting area LA composed of a plurality of light source blocks LB. In addition, the light emitting area LA may include a first area A1 including a plurality of light source blocks LBa, a second area A2 including a plurality of light source blocks LBb, and a third area A3 including a plurality of light source blocks LBc. According to an example, the first area A1 may be closer to the power supply unit 120 and the light source driver 130 mounted on the printed circuit board 140 than the second area A2 and the third area A3, and the second area A2 may be closer to the power supply unit 120 and the light source driver 130 than the third area A3. In other words, the distance between the light source block LBa of the first area A1 and the light source driver 130 may be smaller than the distance between the light source block LBb or the light source block LBc and the light source driver 130 of each of the second area A2 and the third area A3. Therefore, the length of each of the first sensing lines SLa connected between the light source block LBa of the first area A1 and the first light source driver 131 may be smaller than the length of each of the second sensing lines SLb connected between the light source block LBb of the second area A2 and the second light source driver 132. In addition, the length of each of the second sensing lines SLb connected between the light source block LBb of the second area A2 and the second light source driver 132 may be smaller than the length of each of the third sensing lines SLc connected between the light source block LBc of the third area A3 and the third light source driver 133 .

[0120] Each of the power supply units 120 may include first to third power supply units 121 to 123 , and each of the light source drivers 130 may include first to third light source drivers 131 to 133 .

[0121] The first power supply unit 121 can generate a first driving voltage VLED1 based on the first feedback voltage FB1 and supply the first driving voltage VLED1 to the light source block LBa of the first area A1 through the first power line VL1. The second power supply unit 122 can generate a second driving voltage VLED2 based on the second feedback voltage FB2 and supply the second driving voltage VLED2 to the light source block LBb of the second area A2 through the second power line VL2. The third power supply unit 123 can generate a third driving voltage VLED3 based on the third feedback voltage FB3 and supply the third driving voltage VLED3 to the light source block LBc of the third area A3 through the third power line VL3.

[0122] The first light source driver 131 can control the current flowing through the light source block LBa of the first area A1 through the first sensing line SLa, the second light source driver 132 can control the current flowing through the light source block LBb of the second area A2 through the second sensing line SLb, and the third light source driver 133 can control the current flowing through the light source block LBc of the third area A3 through the third sensing line SLc.

[0123] For example, the first area A1 may include the first light source block LB1 to the nth light source block LB(n) (where n is a natural number of 2 or more), the second area A2 may include the n+1th light source block LB(n+1) to the 2nth light source block LB(2n), and the third area A3 may include the 2n+1th light source block LB(2n+1) to the 3nth light source block LB(3n). In addition, the first light source block LB1 to the nth light source block LB(n) may be connected to the first light source driver 131 through the first sensing lines SL1 to SL(n), respectively, the n+1th light source block LB(n+1) to the 2nth light source block LB(2n) may be connected to the second light source driver 132 through the second sensing lines SL(n+1) to SL(2n), respectively, and the 2n+1th light source block LB(2n+1) to the 3nth light source block LB(3n) may be connected to the third light source driver 133 through the third sensing lines SL(2n+1) to SL(3n), respectively. That is, the length of each of the first sensing lines SL1 to SL(n) may be smaller than the length of each of the second sensing lines SL(n+1) to SL(2n) or the length of each of the third sensing lines SL(2n+1) to SL(3n).

[0124] Since the first sensing lines SL1 to SL(n) have different cross-sectional areas according to the lengths of the first sensing lines SL1 to SL(n), they can have the same first resistance value. Similarly, since the second sensing lines SL(n+1) to SL(2n) have different cross-sectional areas according to the lengths of the second sensing lines SL(n+1) to SL(2n), they can have the same second resistance value. In addition, since the third sensing lines SL(2n+1) to SL(3n) have different cross-sectional areas according to the lengths of the third sensing lines SL(2n+1) to SL(3n), they can have the same third resistance value.

[0125] Since the first sensing lines SL1 to SL(n) have the same first resistance value as described above, the first driving voltage VLED1 provided from the first power supply unit 121 may be reduced to the same voltage value in each of the first to n-th light source blocks LB1 to LB(n), each of the first sensing lines SL1 to SL(n), and the first light source driver 131. For example, the voltage reduced in each of the first light source block LB1, the first sensing line SL1 connected to the first light source block LB1, and the first light source driver 131 may be the same as the voltage reduced in each of the n-th light source block LB(n), the first sensing line SL(n) connected to the n-th light source block LB(n), and the first light source driver 131.

[0126] In addition, since the second sensing lines SL(n+1) to SL(2n) have the same second resistance value, the second driving voltage VLED2 provided from the second power supply unit 122 may be reduced to the same voltage value in each of the n+1th light source block LB(n+1) to the 2nth light source block LB(2n), each of the second sensing lines SL(n+1) to SL(2n), and the second light source driver 132. For example, the voltage reduced in each of the n+1th light source block LB(n+1), the second sensing line SL(n+1) connected to the n+1th light source block LB(n+1), and the second light source driver 132 may be the same as the voltage reduced in each of the 2nth light source block LB(2n), the second sensing line SL(2n) connected to the 2nth light source block LB(2n), and the second light source driver 132.

[0127] In addition, since the third sensing lines SL(2n+1) to SL(3n) have the same third resistance value, the third driving voltage VLED3 provided from the third power supply unit 123 may be reduced to the same voltage value in each of the 2n+1th light source block LB(2n+1) to the 3nth light source block LB(3n), each of the third sensing lines SL(2n+1) to SL(3n), and the third light source driver 133. For example, the voltage reduced in each of the 2n+1th light source block LB(2n+1), the third sensing line SL(2n+1) connected to the 2n+1th light source block LB(2n+1), and the third light source driver 133 may be the same as the voltage reduced in each of the 3nth light source block LB(3n), the third sensing line SL(3n) connected to the 3nth light source block LB(3n), and the third light source driver 133.

[0128] Therefore, compared with the backlight unit according to the first embodiment, the backlight unit 100 according to the second embodiment further includes a third power supply unit 123 for applying a third driving voltage VLED3, third sensing lines SL(2n+1) to SL(3n) having a third resistance value, and a third light source driver 133 for controlling current flowing through the third sensing lines SL(2n+1) to SL(3n). That is, the backlight unit 100 according to the second embodiment requires more components than the backlight unit according to the first embodiment, but can further reduce power consumption compared with the first embodiment, and improve its efficiency by effectively preventing the first to third light source drivers 131 to 133 from generating heat.

[0129] Fig. 9 yes Figure 7 A circuit diagram of an example of a backlight unit is shown in FIG.

[0130] Reference Fig. 9 , the first power supply unit 121 may output a first driving voltage VLED1 by boosting the DC input voltage VIN. According to an example, the first power supply unit 121 may include a driving voltage controller (DC-DC driver). The driving voltage controller (DC-DC driver) may turn on the first transistor T1 in response to a first feedback voltage FB1 received from the first light source driver 131 (LED driver). Here, the driving voltage controller (DC-DC driver) may determine the magnitude of the first driving voltage VLED1 by adjusting the turn-on time of the first transistor T1 based on the first feedback voltage FB1. The first driving voltage VLED1 thus generated may be supplied in parallel to the light source blocks LBa disposed in the first area A1.

[0131] The second power supply unit 122 may output a second driving voltage VLED2 by boosting the DC input voltage VIN. According to an example, the second power supply unit 122 may include a driving voltage controller (DC-DC driver). The driving voltage controller (DC-DC driver) may turn on the first transistor T1 in response to a second feedback voltage FB2 received from the second light source driver 132 (LED driver). Here, the driving voltage controller (DC-DC driver) may determine the magnitude of the second driving voltage VLED2 by adjusting the turn-on time of the first transistor T1 based on the second feedback voltage FB2. The second driving voltage VLED2 thus generated may be supplied in parallel to the light source blocks LBb disposed in the second area A2.

[0132] The third power supply unit 123 may output a third driving voltage VLED3 by boosting the DC input voltage VIN. According to an example, the third power supply unit 123 may include a driving voltage controller (DC-DC driver). The driving voltage controller (DC-DC driver) may turn on the first transistor T1 in response to a third feedback voltage FB3 received from the third light source driver 133 (LED driver). Here, the driving voltage controller (DC-DC driver) may determine the magnitude of the third driving voltage VLED3 by adjusting the turn-on time of the first transistor T1 based on the third feedback voltage FB3. The third driving voltage VLED3 thus generated may be supplied in parallel to the light source blocks LBc disposed in the third area A3.

[0133] Fig.10 It is shown Figure 7 Circuit diagram of the voltage drop of the backlight unit shown in FIG.

[0134] Reference Fig.10 , the first driving voltage VLED1 can be reduced through each of the first light source block LB1 to the nth light source block LB(n)(LBa), each of the first sensing lines SLa, and the first light source driver 131. Specifically, the first light source driver 131 may include a second transistor T2 and an amplifier AMP connected to the gate electrode of the second transistor T2. Therefore, the first light source driver 131 can control the conduction of the second transistor T2 through the amplifier AMP, so that a current I of a specific size flows through each of the first light source block LB1 to the nth light source block LB(n)(LBa), each of the first sensing lines SLa, and the first light source driver 131.

[0135] The second driving voltage VLED2 may be reduced by each of the n+1th light source block LB(n+1) to the 2nth light source block LB(2n)(LBb), each of the second sensing lines SLb, and the second light source driver 132. Specifically, the second light source driver 132 may include a second transistor T2 and an amplifier AMP connected to a gate electrode of the second transistor T2. The second light source driver 132 may control the conduction of the second transistor T2 through the amplifier AMP so that a current I of a specific size flows through each of the n+1th light source block LB(n+1) to the 2nth light source block LB(2n)(LBb), each of the second sensing lines SLb, and the second light source driver 132.

[0136] The third driving voltage VLED3 may be reduced by each of the 2n+1th to 3nth light source blocks LB(2n+1) to LB(3n)(LBc), each of the third sensing lines SLc, and the third light source driver 133. Specifically, the third light source driver 133 may include a second transistor T2 and an amplifier AMP connected to a gate electrode of the second transistor T2. The third light source driver 133 may control the conduction of the second transistor T2 through the amplifier AMP so that a current I of a specific size flows through each of the 2n+1th to 3nth light source blocks LB(2n+1) to LB(3n)(LBc), each of the third sensing lines SLc, and the third light source driver 133.

[0137] For example, the first driving voltage VLED1 may be reduced by the voltage VLB applied to each of the first to n-th light source blocks LB1 to LB(n)(LBa), the voltage I×R1 applied to the first sensing line SLa, the voltage VT applied to the second transistor T2, and the voltage I×RL applied to the load resistor RL (VLED1=VLB+I×R1+VT+I×RL). In this way, the first driving voltage VLED1 supplied in parallel to the first to n-th light source blocks LB1 to LB(n)(LBa) may be reduced to the same size in all the first sensing lines SLa.

[0138] In addition, the second driving voltage VLED2 can be reduced by the voltage VLB applied to each of the n+1th light source block LB(n+1) to the 2nth light source block LB(2n)(LBb), the voltage I×R2 applied to the second sensing line SLb, the voltage VT applied to the second transistor T2, and the voltage I×RL applied to the load resistor RL (VLED2=VLB+I×R2+VT+I×RL). In this way, the second driving voltage VLED2 supplied in parallel to the n+1th light source block LB(n+1) to the 2nth light source block LB(2n)(LBb) can be reduced to the same size in all the second sensing lines SLb.

[0139] In addition, the third driving voltage VLED3 can be reduced by the voltage VLB applied to each of the 2n+1th light source block LB(2n+1) to the 3nth light source block LB(3n)(LBc), the voltage I×R3 applied to the third sensing line SLc, the voltage VT applied to the second transistor T2, and the voltage I×RL applied to the load resistor RL (VLED3=VLB+I×R3+VT+I×RL). In this way, the third driving voltage VLED3 supplied in parallel to the 2n+1th light source block LB(2n+1) to the 3nth light source block LB(3n)(LBc) can be reduced to the same size in all the third sensing lines SLc.

[0140] Therefore, the difference between the first driving voltage VLED1 and the second driving voltage VLED2 may correspond to the difference between the voltage I×R1 applied to the first sensing line SLa and the voltage I×R2 applied to the second sensing line SLb (VLED2-VLED1=I×R2-I×R1). In addition, the difference between the second driving voltage VLED2 and the third driving voltage VLED3 may correspond to the difference between the voltage I×R2 applied to the second sensing line SLb and the voltage I×R3 applied to the third sensing line SLc (VLED3-VLED2=I×R3-I×R2).

[0141] As described above, since the first area A1 of the substrate 110 is disposed closer to the power supply unit 120 and the light source driver 130 than the second area A2 and the third area A3, the first sensing lines SL1 to SL(n) may have the same first resistance value R1, the second sensing lines SL(n+1) to SL(2n) may have the same second resistance value R2, and the third sensing lines SL(2n+1) to SL(3n) may have the same third resistance value R3. In addition, the first resistance value R1 may be designed to be smaller than the second resistance value R2, and the second resistance value R2 may be designed to be smaller than the third resistance value R3.

[0142] Therefore, the first power supply unit 121 can supply the first driving voltage VLED1 which is smaller than the second driving voltage VLED2 and the third driving voltage VLED3 to the first light source block LB1 to the nth light source block LB(n) respectively connected to the first sensing lines SL1 to SL(n) having the first resistance value R1, thereby minimizing the power consumed in the first sensing lines SL1 to SL(n) and preventing the first light source driver 131 from heating.

[0143] Similarly, the second power supply unit 122 can supply a second driving voltage VLED2 that is smaller than the third driving voltage VLED3 to the n+1th light source blocks LB(n+1) to the 2nth light source blocks LB(2n) respectively connected to the second sensing lines SL(n+1) to SL(2n) having the second resistance values ​​R2, thereby minimizing the power consumed in the second sensing lines SL(n+1) to SL(2n) and preventing heating of the second light source driver 132.

[0144] In addition, the third power supply unit 123 can supply the third driving voltage VLED3 to each of the 2n+1th light source blocks LB(2n+1) to the 3nth light source blocks LB(3n) respectively connected to the third sensing lines SL(2n+1) to SL(3n) having the same third resistance value R3, thereby minimizing the power consumed in the third sensing lines SL(2n+1) to SL(3n) and preventing heating of the third light source driver 133.

[0145] Fig.11is based on Figure 1 0048 is a plan view of a backlight unit of a third embodiment in a display device shown in FIG. Fig.12 It is shown Fig.11 An example diagram of region AC and the connection relationship in region AC. Fig.13 It is shown Fig.11 Another example diagram of region AC and the connection relationship in region AC. The same elements as those described above will be briefly described or will not be described below.

[0146] Reference Fig.11 and Fig.12 , the substrate 110 may include a light emitting area LA composed of a plurality of light source blocks LB. In addition, the light emitting area LA may include first to n-th light source blocks LB1 to LB(n) (where n is a natural number of 2 or more).

[0147] Each of the power supply units 120 may supply the driving voltage VLED to the light source block LB through the power supply line VL. Specifically, each of the power supply units 120 may receive a feedback voltage FB from the light source driver 130 and generate the driving voltage VLED based on the feedback voltage FB.

[0148] According to an embodiment, the power lines VL respectively connected to the first to nth light source blocks LB1 to LB(n) may have the same resistance value. Therefore, the backlight unit 100 according to the present disclosure may minimize power consumed in the power lines VL.

[0149] Each of the light source drivers 130 may control the current flowing through the light source block LB through the sensing line SL. For example, the light emitting area LA may include first to n-th light source blocks LB1 to LB(n), and the first to n-th light source blocks LB1 to LB(n) may be connected to each of the light source drivers 130 through the sensing lines SL1 to SL(n), respectively.

[0150] exist Fig.12 In the embodiment, the sensing line SL1 connected to the first light source block LB1 may be shorter than the sensing line SL2 connected to the second light source block LB2. In this way, the sensing lines SL1 to SL(n) may be relatively long or short according to the distances between the first to n-th light source blocks LB1 to LB(n) and the light source driver 130.

[0151] The sensing lines SL1 to SL(n) may have the same resistance value. According to an example, the sensing lines SL1 to SL(n) may have different lengths according to the positions of the first to nth light source blocks LB1 to LB(n), respectively. Since the sensing lines SL1 to SL(n) have different cross-sectional areas according to the lengths of the sensing lines SL1 to SL(n), respectively, they may have the same resistance value. In addition, since the sensing lines SL1 to SL(n) respectively have cross-sectional areas proportional to the distances between the light source blocks LB and the light source driver 130, they may have the same resistance value.

[0152] exist Fig.13 , the cross-sectional area and length of the sensing line SL1 connected to the first light source block LB1 may be the same as the cross-sectional area and length of the sensing line SL2 connected to the second light source block LB2. For example, since the sensing line SL1 connected to the first light source block LB1 is closer to the light source driver 130 than the sensing line SL2 connected to the second light source block LB2, the sensing line SL1 connected to the first light source block LB1 may be more curved than the sensing line SL2 connected to the second light source block LB2. In this way, since the sensing lines SL1 to SL(n) have the same cross-sectional area and length, they may have the same resistance value.

[0153] Since the sensing lines SL1 to SL(n) have the same resistance value as described above, the driving voltage VLED provided from the power supply unit 120 may be reduced to the same voltage value in each of the first to n-th light source blocks LB1 to LB(n), each of the sensing lines SL1 to SL(n), and the light source driver 130. For example, the voltage reduced in each of the first light source block LB1, the sensing line SL1 connected to the first light source block LB1, and the light source driver 130 may be the same as the voltage reduced in each of the n-th light source block LB(n), the sensing line SL(n) connected to the n-th light source block LB(n), and the light source driver 130.

[0154] Therefore, the backlight unit 100 according to the third embodiment may have an optimal structure for preventing power consumption and heat generation by using relatively fewer elements than the first and second embodiments.

[0155] Fig.14 yes Fig.11 A circuit diagram of an example of a backlight unit is shown in FIG.

[0156] Reference Fig.14, the power supply unit 120 may output the driving voltage VLED by increasing the DC input voltage VIN. According to an example, the power supply unit 120 may include a driving voltage controller (DC-DC driver). The driving voltage controller (DC-DC driver) may turn on the first transistor T1 in response to the feedback voltage FB received from the light source driver 130 (LED driver). Here, the driving voltage controller (DC-DC driver) may determine the magnitude of the driving voltage VLED by adjusting the turn-on time of the first transistor T1 based on the feedback voltage FB. The driving voltage VLED thus generated may be supplied to the light source blocks LB in parallel.

[0157] Fig.15 It is shown Fig.11 Circuit diagram of the voltage drop of the backlight unit shown in FIG.

[0158] Reference Fig.15 , the driving voltage VLED can be reduced through each of the first light source block LB1 to the n-th light source block LB(n)(LB), each of the sensing lines SL, and the light source driver 130. Specifically, the light source driver 130 may include a second transistor T2 and an amplifier AMP connected to the gate electrode of the second transistor T2. Therefore, the light source driver 130 can control the conduction of the second transistor T2 through the amplifier AMP, so that a current I of a specific size flows through each of the first light source block LB1 to the n-th light source block LB(n)(LB), each of the first sensing lines SL, and the light source driver 130.

[0159] For example, the driving voltage VLED may be reduced by the voltage VLB applied to each of the first to n-th light source blocks LB1 to LB(n)(LB), the voltage I×R applied to the sensing line SL, the voltage VT applied to the second transistor T2, and the voltage I×RL applied to the load resistor RL (VLED=VLB+I×R+VT+I×RL). In this way, the driving voltage VLED supplied in parallel to the first to n-th light source blocks LB1 to LB(n)(LB) may be reduced to the same size in all the sensing lines SL.

[0160] Therefore, the power supply unit 120 can supply the same driving voltage VLED to each of the first to nth light source blocks LB1 to LB(n) respectively connected to the sensing lines SL1 to SL(n) having the same resistance value R, thereby minimizing the power consumed in the sensing lines SL1 to SL(n) and preventing heating of the light source driver 130.

[0161] Fig.16 is an exploded perspective view of a display device according to an embodiment. Fig.17 is based on Fig.16A plan view of a backlight unit of a fourth embodiment of a display device shown in FIG. Fig.16 and Fig.17 The display device shown in Figure 1 and Figure 2 The display device shown in FIG. 1 is different in the configurations of the power supply unit 120, the light source driver 130, the printed circuit board 140, and the plurality of flexible films 150. Therefore, the same elements as those described above will be briefly described or will not be described. In addition, Fig.18 It is shown Fig.17 An example diagram of area AD and the connection relationship in area AD. Fig.19 It is shown Fig.17 Another example diagram of area AD and the connection relationship in area AD.

[0162] Reference Figures 16 to 19 , the backlight unit 100 may include a substrate 110 , a power supply unit 120 , a light source driver 130 , a printed circuit board 140 , and a flexible film 150 .

[0163] The substrate 110 may include a light emitting area LA composed of a plurality of light source blocks LB. In addition, the light emitting area LA may include a first area A1 including a plurality of light source blocks LBa and a second area A2 including a plurality of light source blocks LBb. According to an example, the first area A1 may be adjacent to the first power supply unit 121 and the first light source driver 131 mounted on the first printed circuit board 141, and the second area A2 may be adjacent to the second power supply unit 122 and the second light source driver 132 mounted on the second printed circuit board 142.

[0164] The power supply unit 120 may include a first power supply unit 121 and a second power supply unit 122. The first power supply unit 121 may be disposed adjacent to the first area A1 of the substrate 110, and the second power supply unit 122 may be disposed adjacent to the second area A2 of the substrate 110.

[0165] Each of the first power supply units 121 may supply a driving voltage VLED to the light source block LBa of the first area A1 through a power line VL, and each of the second power supply units 122 may supply a driving voltage VLED to the light source block LBb of the second area A2 through a power line VL. For example, the first power supply unit 121 and the second power supply unit 122 may supply the same driving voltage VLED to the light source block LBa of the first area A1 and the light source block LBb of the second area A2.

[0166] Specifically, each of the first power supply units 121 may receive a feedback voltage FB from the first light source driver 131 and generate a driving voltage VLED based on the feedback voltage FB. Each of the second power supply units 122 may receive a feedback voltage FB from the second light source driver 132 and generate a driving voltage VLED based on the feedback voltage FB.

[0167] According to an example, a plurality of power lines VL respectively connected to the first light source block LB1 to the nth light source block LB(n) may have the same resistance value, and a plurality of power lines VL respectively connected to the n+1th light source block LB(n+1) to the 2nth light source block LB(2n) may have the same resistance value. Therefore, the backlight unit 100 according to the present disclosure can minimize the power consumed in the power line VL.

[0168] The light source driver 130 may include a first light source driver 131 and a second light source driver 132. The first light source driver 131 may be disposed adjacent to the first area A1 of the substrate 110, and the second light source driver 132 may be disposed adjacent to the second area A2 of the substrate 110.

[0169] Each of the first light source drivers 131 may control current flowing through the light source block LBa of the first area A1 through the first sensing line SLa, and each of the second light source drivers 132 may control current flowing through the light source block LBb of the second area A2 through the second sensing line SLb.

[0170] According to an example, the number of light source blocks LBa of the first area A1 may be equal to the number of light source blocks LBb of the second area A2, but is not necessarily limited thereto. For example, the first area A1 may include the first light source block LB1 to the nth light source block LB(n) (where n is a natural number of 2 or more), and the second area A2 may include the n+1th light source block LB(n+1) to the 2nth light source block LB(2n). In addition, the first light source block LB1 to the nth light source block LB(n) may be connected to each of the first light source drivers 131 through the first sensing lines SL1 to SL(n), respectively, and the n+1th light source block LB(n+1) to the 2nth light source block LB(2n) may be connected to each of the second light source drivers 132 through the second sensing lines SL(n+1) to SL(2n), respectively. Here, the lengths of the first sensing lines SL1 to SL(n) may be the same as the lengths of the second sensing lines SL(n+1) to SL(2n), respectively.

[0171] exist Fig.18, the first sensing line SL1 connected to the first light source block LB1 may be shorter than the first sensing line SL2 connected to the second light source block LB2. In this way, the first sensing lines SL1 to SL(n) may be relatively long or relatively short, respectively, according to the distances between the first light source block LB1 to the nth light source block LB(n) and the first light source driver 131. In addition, the second sensing line SL(n+1) connected to the n+1th light source block LB(n+1) may be longer than the second sensing line SL(n+2) connected to the n+2th light source block LB(n+2). In this way, the second sensing lines SL(n+1) to SL(2n) may be relatively long or relatively short, respectively, according to the distances between the n+1th light source block LB(n+1) to the 2nth light source block LB(2n) and the second light source driver 132.

[0172] The first sensing lines SL1 to SL(n) may have the same resistance value. According to an example, the first sensing lines SL1 to SL(n) may have different lengths according to the positions of the first to nth light source blocks LB1 to LB(n), respectively. Since the first sensing lines SL1 to SL(n) have different cross-sectional areas according to the lengths of the first sensing lines SL1 to SL(n), respectively, they may have the same resistance value. In addition, since the first sensing lines SL1 to SL(n) respectively have cross-sectional areas proportional to the distances between the light source blocks LBa of the first area A1 and the first light source driver 131, they may have the same resistance value.

[0173] The second sensing lines SL(n+1) to SL(2n) may have the same resistance value. According to an example, the second sensing lines SL(n+1) to SL(2n) may have different lengths according to the positions of the n+1th light source blocks LB(n+1) to the 2nth light source blocks LB(2n). Since the second sensing lines SL(n+1) to SL(2n) have different cross-sectional areas according to the lengths of the second sensing lines SL(n+1) to SL(2n), they may have the same resistance value. In addition, since the second sensing lines SL(n+1) to SL(2n) respectively have cross-sectional areas proportional to the distances between the light source blocks LBb of the second area A2 and the second light source driver 132, they may have the same resistance value.

[0174] exist Fig.19, the cross-sectional area and length of the first sensing line SL1 connected to the first light source block LB1 may be the same as the cross-sectional area and length of the first sensing line SL2 connected to the second light source block LB2. For example, since the first sensing line SL1 connected to the first light source block LB1 is closer to the first light source driver 131 than the first sensing line SL2 connected to the second light source block LB2, the first sensing line SL1 connected to the first light source block LB1 may be more curved than the sensing line SL2 connected to the second light source block LB2. In this way, since the first sensing lines SL1 to SL(n) have the same cross-sectional area and length, they may have the same resistance value.

[0175] In addition, the cross-sectional area and length of the second sensing line SL(2n) connected to the 2nth light source block LB(2n) may be the same as the cross-sectional area and length of the second sensing line SL(2n-1) connected to the 2n-1th light source block LB(2n-1). For example, since the second sensing line SL(2n) connected to the 2nth light source block LB(2n) is closer to the second light source driver 132 than the second sensing line SL(2n-1) connected to the 2n-1th light source block LB(2n-1), the second sensing line SL(2n) connected to the 2nth light source block LB(2n) may be more curved than the second sensing line SL(2n-1) connected to the 2n-1th light source block LB(2n-1). In this way, since the second sensing lines SL(n+1) to SL(2n) have the same cross-sectional area and length, they may have the same resistance value.

[0176] Since the first sensing lines SL1 to SL(n) have the same resistance value as described above, the driving voltage VLED provided from the first power supply unit 121 may be reduced to the same voltage value in each of the first to n-th light source blocks LB1 to LB(n), each of the first sensing lines SL1 to SL(n), and the first light source driver 131. For example, the voltage reduced in each of the first light source block LB1, the first sensing line SL1 connected to the first light source block LB1, and the first light source driver 131 may be the same as the voltage reduced in each of the n-th light source block LB(n), the first sensing line SL(n) connected to the n-th light source block LB(n), and the first light source driver 131.

[0177] In addition, since the second sensing lines SL(n+1) to SL(2n) have the same resistance value, the driving voltage VLED provided from the second power supply unit 122 may be reduced to the same voltage value in each of the n+1th light source block LB(n+1) to the 2nth light source block LB(2n), each of the second sensing lines SL(n+1) to SL(2n), and the second light source driver 132. For example, the voltage reduced in each of the n+1th light source block LB(n+1), the second sensing line SL(n+1) connected to the n+1th light source block LB(n+1), and the second light source driver 132 may be the same as the voltage reduced in each of the 2nth light source block LB(2n), the second sensing line SL(2n) connected to the 2nth light source block LB(2n), and the second light source driver 132.

[0178] Therefore, the backlight unit 100 according to the fourth embodiment requires more printed circuit boards 140 and flexible films 150 than the backlight unit according to the first embodiment, but the maximum distance between the light source block LB and the first light source driver 131 or the second light source driver 132 can be reduced compared with the first to third embodiments. Therefore, the resistance values ​​of the second sensing lines SL(n+1) to SL(2n) of the backlight unit 100 according to the fourth embodiment can be smaller than the resistance values ​​of the second sensing lines SL(n+1) to SL(2n) of the backlight unit 100 according to other embodiments. Therefore, the backlight unit 100 according to the fourth embodiment can further reduce power consumption compared with the first to third embodiments and can improve its efficiency by effectively preventing the first light source driver 131 and the second light source driver 132 from heating.

[0179] Although the embodiments of the invention have been described above with reference to the accompanying drawings, it will be understood by those skilled in the art that the invention can be implemented in other specific forms without changing the technical spirit or essential features of the invention. Therefore, it will be understood that the above embodiments are illustrative and not restrictive in all aspects.

Claims

1. A backlight unit, comprising: A substrate including a first area and a second area, each of the first area and the second area having a plurality of light source blocks; a light source driver disposed on at least one side of the substrate and connected to the plurality of light source blocks in each of the first area and the second area through each of a first sensing line and a second sensing line; as well as a power supply unit that supplies a first driving voltage to the plurality of light source blocks in the first area and supplies a second driving voltage to the plurality of light source blocks in the second area, wherein the first sensing line connected to each of the plurality of light source blocks in the first area has a first resistance value, and the second sensing line connected to each of the plurality of light source blocks in the second area has a second resistance value, and The first area is closer to the light source driver than the second area, and the first driving voltage is smaller than the second driving voltage, and The difference between the first driving voltage and the second driving voltage corresponds to the difference between a voltage applied to the first sensing line and a voltage applied to the second sensing line.

2. The backlight unit according to claim 1, wherein: Each of the first sensing line and the second sensing line has a different cross-sectional area according to a length of each of the first sensing line and the second sensing line.

3. The backlight unit according to claim 1, wherein: Each of the first sensing lines has a cross-sectional area proportional to the distance between each of the multiple light source blocks in the first area and the light source driver, and each of the second sensing lines has a cross-sectional area proportional to the distance between each of the multiple light source blocks in the second area and the light source driver.

4. The backlight unit according to claim 1, wherein: The first region is closer to the light source driver than the second region, and the first resistance value is smaller than the second resistance value.

5. The backlight unit according to claim 1, wherein: The power supply unit generates the first driving voltage and the second driving voltage based on each of a first feedback voltage and a second feedback voltage received from the light source driver.

6. The backlight unit according to claim 1, wherein: The power supply unit supplies each of the first driving voltage and the second driving voltage through each of a first power line and a second power line, and the first power line and the second power line have the same resistance value.

7. The backlight unit according to claim 1, wherein: The substrate further includes a third region having a plurality of light source blocks, and the light source driver is connected to the plurality of light source blocks of the third region through a third sensing line having a third resistance value.

8. The backlight unit according to claim 7, wherein: The third sensing lines have different cross-sectional areas according to a length of each of the third sensing lines.

9. The backlight unit according to claim 7, further comprising: The power supply unit provides first to third driving voltages to the plurality of light source blocks in the first to third regions, respectively, based on first to third feedback voltages received from the light source driver.

10. The backlight unit according to claim 1, wherein: The light source driver comprises: a first light source driver disposed adjacent to the first area and connected to the plurality of light source blocks of the first area; and A second light source driver is disposed adjacent to the second area and connected to the plurality of light source blocks of the second area.

11. The backlight unit according to claim 10, further comprising: A power supply unit supplies the same driving voltage to the plurality of light source blocks of the first region and the plurality of light source blocks of the second region, wherein the first resistance value and the second resistance value are equal to each other.

12. The backlight unit according to claim 10, wherein: Each of the first sensing line and the second sensing line has a different cross-sectional area according to a length of each of the first sensing line and the second sensing line.

13. The backlight unit according to claim 10, wherein: The first sensing line and the second sensing line have the same cross-sectional area and length.

14. The backlight unit according to claim 1, wherein: Each of the plurality of light source blocks includes at least one small light emitting diode or a micro light emitting diode.

15. A display device, comprising: A display panel for displaying images; as well as The backlight unit according to any one of claims 1 to 14 irradiates light toward the display panel.

Images