Backlight unit and display apparatus including same

Abstract

A display apparatus, according to one aspect of the disclosed invention, comprises: a liquid crystal panel; and a backlight unit providing light to the liquid crystal panel, the backlight unit including: a substrate; and a plurality of dimming blocks arranged on the substrate in a plurality of rows and a plurality of columns, each dimming block including a red LED, a green LED, and a blue LED, wherein the red LED, the green LED, and the blue LED included in each of the plurality of dimming blocks may be divided into different numbers of LED cells, and the divided LED cells may be connected in series with each other.

Description

Backlight unit and display device including the same

[0001] The disclosed invention relates to a display device, and more specifically, to a display device comprising a liquid crystal panel and a back light unit (BLU).

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

[0003] The display device includes a back light unit (BLU) that provides light to a liquid crystal panel, and the back light unit includes a plurality of point light-emitting elements capable of emitting light independently. The light-emitting elements include, for example, light-emitting diodes (LEDs) or organic light-emitting diodes (OLEDs).

[0004] Among these, local dimming technology in the backlight unit of an LED TV is a key technology for enhancing the contrast ratio of the display. The local dimming system divides the display screen into multiple zones and can independently adjust the current for each zone according to the input image. Accordingly, it can effectively improve the contrast ratio by lowering the current when the input image is dark and increasing the current when the input image is bright.

[0005] When such a local dimming system is implemented in a Red / Green / Blue LED-based LED backlight, the block voltage for each color LED may differ when driven using a common block voltage.

[0006] One aspect of the disclosed invention provides a backlight unit and a display device including the same, wherein the number of LED cells is varied according to the color of the LEDs included in the backlight unit so that the block voltages of the LEDs for each color can be made similar to each other.

[0007] In addition, the present invention provides a backlight unit and a display device including the same, wherein current is distributed to each LED cell so that the LED cells are driven at a relatively low current, thereby increasing driving efficiency.

[0008] The technical problems to be solved in this document are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art to which this invention belongs from the description below.

[0009] A display device according to one aspect of the disclosed invention comprises: a liquid crystal panel; and a backlight unit that provides light to the liquid crystal panel. The backlight unit comprises: a substrate; and a plurality of dimming blocks arranged in a plurality of rows and a plurality of columns on the substrate, each comprising a red LED, a green LED, and a blue LED. The red LED, green LED, and blue LED included in each of the plurality of dimming blocks are each divided into a different number of LED cells, and the divided LED cells can be connected in series with each other.

[0010] A backlight unit according to one aspect of the disclosed invention comprises: a substrate; a plurality of dimming blocks arranged in a plurality of rows and a plurality of columns on the substrate, each including a red LED, a green LED, and a blue LED; wherein the red LED, green LED, and blue LED included in each of the plurality of dimming blocks are each divided into a different number of LED cells, and the divided LED cells can be connected in series with each other.

[0011] FIG. 1 illustrates an example of the appearance of a display device according to one embodiment.

[0012] FIG. 2 illustrates an example of the structure of a display device according to one embodiment.

[0013] FIG. 3 illustrates an example of a liquid crystal panel included in a display device according to one embodiment.

[0014] FIG. 4 illustrates an example of a back light unit (BLU) included in a display device according to one embodiment.

[0015] FIG. 5 is a diagram illustrating that a plurality of light-emitting diodes of a backlight unit according to one embodiment are divided into dimming blocks.

[0016] FIG. 6 is a diagram showing a control block diagram of a display device according to one embodiment.

[0017] FIG. 7 illustrates an example of a display device according to one embodiment converting dimming data from image data.

[0018] FIG. 8 illustrates an example of a light-emitting element included in a backlight unit according to one embodiment.

[0019] FIG. 9 is a drawing showing a plurality of local dimming blocks according to one embodiment.

[0020] FIG. 10 illustrates the arrangement of a dimming driver, a driving element, and a light-emitting element included in a display device according to one embodiment.

[0021] FIG. 11 is a diagram showing that each light-emitting element according to one embodiment is divided into a plurality of cells.

[0022] FIG. 12 is a diagram illustrating the cell voltage of each light-emitting element according to one embodiment.

[0023] FIG. 13 is a diagram showing the connection relationship of each plurality of cells of each light-emitting element according to one embodiment.

[0024] FIGS. 14 and 15 are drawings for explaining the connection wiring of a driving element and each light-emitting element according to one embodiment.

[0025] The embodiments described in this specification and the configurations illustrated in the drawings are merely preferred examples of the disclosed invention, and various modifications that may replace the embodiments and drawings of this specification may exist at the time of filing this application.

[0026] Additionally, the same reference numerals or symbols presented in each drawing of this specification represent parts or components that perform substantially the same function.

[0027] Furthermore, the terms used in this specification are for describing embodiments and are not intended to limit or / or restrict the disclosed invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "comprising" or "having" are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and do not preclude the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0028] Additionally, in this specification, when a configuration is described as being "connected" or "combined" with another configuration, this includes not only cases where they are directly connected or combined, but also cases where they are indirectly connected or combined.

[0029] Additionally, terms including ordinal numbers, such as "first," "second," etc., as used herein may be used to describe various components, but said components are not limited by said terms, and said terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be named the second component, and similarly, the second component may be named the first component. The term "and / or" includes a combination of a plurality of related described items or any one of a plurality of related described items.

[0030] Hereinafter, embodiments according to the present invention will be described with reference to the attached drawings.

[0031] FIG. 1 illustrates an example of the appearance of a display device according to one embodiment.

[0032] Referring to FIG. 1, the display device (10) is a device capable of processing a video signal received from the outside and visually displaying the processed video. In the following examples, the display device (10) is exemplified as a television (TV), but is not limited thereto. For example, the display device (10) can be implemented in various forms such as a monitor, a portable multimedia device, a portable communication device, etc., and the form of the display device (10) is not limited as long as it is a device that visually displays video.

[0033] In addition, the display device (10) may be a large format display (LFD) installed outdoors, such as on a building rooftop or at a bus stop. Here, the outdoor area is not necessarily limited to an open space; the display device (10) according to one embodiment may be installed in any indoor location where many people can enter and exit, such as a subway station, shopping mall, movie theater, company, or store.

[0034] The display device (10) receives content including video signals and audio signals from various content sources and can output video and audio corresponding to the video signals and audio signals. For example, the display device (10) can receive content data through a broadcast receiving antenna or a wired cable, receive content data from a content playback device, or receive content data from a content provider's content provision server.

[0035] As illustrated in FIG. 1, the display device (10) may include a main body (11) and a screen (12) that displays an image (I).

[0036] The main body (11) forms the outer shape of the display device (10), and components for the display device (10) to display an image (I) or perform various functions may be provided inside the main body (11). The main body (11) shown in FIG. 1 is in the shape of a flat plate, but the shape of the main body (11) is not limited to that shown in FIG. 1. For example, the main body (11) may be in the shape of a curved plate.

[0037] A screen (12) is formed on the front of the main body (11) and can display an image (I). For example, the screen (12) can display a still image or a video. Additionally, the screen (12) can display a two-dimensional flat image or a three-dimensional stereoscopic image using the parallax of the user's two eyes.

[0038] The screen (12) may include a liquid crystal panel capable of passing through or blocking light emitted by a back light unit (BLU), etc.

[0039] A plurality of pixels (P) are formed on the screen (12), and an image (I) displayed on the screen (12) can be formed by light emitted by each of the plurality of pixels (P). For example, an image (I) can be formed on the screen (12) by combining the light emitted by each of the plurality of pixels (P) as if in a mosaic.

[0040] Each of the plurality of pixels (P) can emit light of various brightness and various colors. In order to emit light of various colors, each of the plurality of pixels (P) may include subpixels (PR, PG, PB).

[0041] The subpixels (PR, PG, PB) may include a red subpixel (PR) capable of emitting red light, a green subpixel (PG) capable of emitting green light, and a blue subpixel (PB) capable of emitting blue light. For example, red light may represent light with a wavelength of approximately 700 nm (nanometer, one-billionth of a meter) to 800 nm. Green light may represent light with a wavelength of approximately 500 nm to 600 nm. Blue light may represent light with a wavelength of approximately 400 nm to 500 nm.

[0042] By combining the red light of the red subpixel (PR), the green light of the green subpixel (PG), and the blue light of the blue subpixel (PB), light of various brightness and various colors can be emitted from each of the multiple pixels (P).

[0043] FIG. 2 illustrates an example of the structure of a display device (10) according to one embodiment, and FIG. 3 illustrates an example of a liquid crystal panel included in a display device (10) according to one embodiment.

[0044] As shown in FIG. 2, various components for generating an image (I) on a screen (S) may be provided inside the main body (11).

[0045] For example, the main body (11) is provided with a back light unit (BLU) (100) which is a surface light source, a liquid crystal panel (20) that blocks or passes light emitted from the back light unit (100), a control assembly (50) that controls the operation of the back light unit (100) and the liquid crystal panel (20), and a power assembly (60) that supplies power to the back light unit (100) and the liquid crystal panel (20). Additionally, the main body (11) may include a bezel (13) for supporting the liquid crystal panel (20), the back light unit (100), the control assembly (50), and the power assembly (60), a frame middle mold (14), a bottom chassis (15), and a rear cover (16).

[0046] The backlight unit (100) may include a point light source that emits white light. Additionally, the backlight unit (100) may refract, reflect, and scatter light to convert the light emitted from the point light source into uniform surface light. In this way, the backlight unit (100) can emit uniform surface light toward the front by refracting, reflecting, and scattering the light emitted from the point light source.

[0047] The backlight unit (100) is described in more detail below.

[0048] A liquid crystal panel (20) is provided in front of a backlight unit (100) and blocks or passes light emitted from the backlight unit (100) to form an image (I).

[0049] The front surface of the liquid crystal panel (20) forms the screen (S) of the display device (10) described above, and the liquid crystal panel (20) can form a plurality of pixels (P). The plurality of pixels (P) of the liquid crystal panel (20) can each independently block or allow light from the backlight unit (100) to pass through. In addition, the light passed through the plurality of pixels (P) can form an image (I) displayed on the screen (S).

[0050] For example, as shown in FIG. 3, the liquid crystal panel (20) may include a first polarizing film (21), a first transparent substrate (22), a pixel electrode (23), a thin film transistor (24), a liquid crystal layer (25), a common electrode (26), a color filter (27), a second transparent substrate (28), and a second polarizing film (29).

[0051] The first transparent substrate (22) and the second transparent substrate (28) can fix and support a pixel electrode (23), a thin-film transistor (24), a liquid crystal layer (25), a common electrode (26), and a color filter (27). These first and second transparent substrates (22, 28) may be composed of reinforced glass or a transparent resin.

[0052] A first polarizing film (21) and a second polarizing film (29) are provided on the outer side of the first and second transparent substrates (22, 28). The first polarizing film (21) and the second polarizing film (29) can each pass a specific polarization and block (reflect or absorb) other polarizations. For example, the first polarizing film (21) can pass polarization of a first direction and block (reflect or absorb) other polarizations. Also, the second polarizing film (29) can pass polarization of a second direction and block (reflect or absorb) other polarizations. At this time, the first direction and the second direction may be orthogonal to each other. As a result, polarization that has passed through the first polarizing film (21) cannot directly pass through the second polarizing film (29).

[0053] A color filter (27) may be provided on the inner side of the second transparent substrate (28). The color filter (27) may include, for example, a red filter (27R) that passes red light, a green filter (27G) that passes green light, and a blue filter (27B) that passes blue light. Additionally, the red filter (27R), the green filter (27G), and the blue filter (27B) may be arranged side by side. The area occupied by the color filter (27) corresponds to the pixel (P) described above. The area occupied by the red filter (27R) corresponds to the red subpixel (PR), the area occupied by the green filter (27G) corresponds to the green subpixel (PG), and the area occupied by the blue filter (27B) corresponds to the blue subpixel (PB).

[0054] The pixel electrode (23) may be provided on the inner side of the first transparent substrate (22), and the common electrode (26) may be provided on the inner side of the second transparent substrate (28). The pixel electrode (23) and the common electrode (26) are made of an electrically conductive metal material and can generate an electric field to change the arrangement of liquid crystal molecules (25a) constituting the liquid crystal layer (25) described below.

[0055] A thin film transistor (TFT) (24) is provided on the inner side of the second transparent substrate (22). The thin film transistor (24) can be turned on (closed) or turned off (open) by image data provided from the panel driver (30). Additionally, depending on the turn-on (closed) or turn-off (open) of the thin film transistor (24), an electric field can be formed or removed between the pixel electrode (23) and the common electrode (26).

[0056] The liquid crystal layer (25) is formed between the pixel electrode (23) and the common electrode (26) and is filled with liquid crystal molecules (25a). The liquid crystal may exhibit an intermediate state between a solid (crystal) and a liquid. The liquid crystal may exhibit optical properties depending on changes in the electric field. For example, the direction of the molecular arrangement constituting the liquid crystal may change depending on changes in the electric field. Consequently, the optical properties of the liquid crystal layer (25) may vary depending on the presence or absence of the electric field passing through the liquid crystal layer (25). For example, the liquid crystal layer (25) may rotate the polarization direction of light around the optical axis depending on the presence or absence of the electric field. Accordingly, the polarization that has passed through the first polarizing film (21) has its polarization direction rotated while passing through the liquid crystal layer (25) and can pass through the second polarizing film (29).

[0057] On one side of the liquid crystal panel (20), a cable (20a) for transmitting video data to the liquid crystal panel (20) and a display driver integrated circuit (DDI) (30) (hereinafter referred to as 'panel driver') for processing digital video data and outputting an analog video signal are provided.

[0058] The cable (20a) electrically connects the control assembly (50) / power assembly (60) and the panel driver (30), and can also electrically connect the panel driver (30) and the liquid crystal panel (20). The cable (20a) may include a flexible flat cable or a film cable, etc.

[0059] The panel driver (30) can receive image data and power from the control assembly (50) / power assembly (60) through the cable (20a). Additionally, the panel driver (30) can provide image data and driving current to the liquid crystal panel (20) through the cable (20a).

[0060] Additionally, the cable (20a) and the panel driver (30) can be implemented as a single unit using a film cable, a chip on film (COF), a tape carrier packet (TCP), etc. In other words, the panel driver (30) can be placed on the cable (20b). However, it is not limited thereto, and the panel driver (30) can be placed on the liquid crystal panel (20).

[0061] The control assembly (50) may include a control circuit that controls the operation of the liquid crystal panel (20) and the backlight unit (100). For example, the control circuit may process video signals and / or audio signals received from an external content source. The control circuit may transmit video data to the liquid crystal panel (20) and dimming data to the backlight unit (100).

[0062] The power assembly (60) may include a power circuit that supplies power to the liquid crystal panel (20) and the backlight unit (100). The power circuit may supply power to the control assembly (50), the backlight unit (100), and the liquid crystal panel (20).

[0063] The control assembly (50) and the power assembly (60) may be implemented with a printed circuit board and various circuits mounted on the printed circuit board. For example, the power circuit may include a capacitor, a coil, a resistor, a processor, etc., and a power circuit board on which these are mounted. Additionally, the control circuit may include a memory, a processor, and a control circuit board on which these are mounted.

[0064] FIG. 4 illustrates an example of a backlight unit (100) included in a display device (10) according to one embodiment, and FIG. 5 is a drawing for explaining that a plurality of light-emitting diodes of the backlight unit (100) according to one embodiment are divided into dimming blocks.

[0065] As illustrated in FIG. 4, the backlight unit (100) may include a light source module (110) that generates light, a reflective sheet (120) that reflects light, a diffuser plate (130) that diffuses light uniformly, and an optical sheet (140) that improves the brightness of the emitted light.

[0066] The light source module (110) may include a plurality of light-emitting elements (111) that emit light and a substrate (112) that supports / fixes the plurality of light-emitting elements (111).

[0067] A plurality of light-emitting elements (111) can be arranged in a predetermined pattern so that light is emitted with uniform brightness. A plurality of light-emitting elements (111) can be arranged so that the distance between one light source and adjacent light sources becomes equal.

[0068] For example, as illustrated in FIG. 4, a plurality of light-emitting elements (111) can be arranged in rows and columns. For example, a plurality of light sources can be arranged so that a square is formed by four adjacent light sources. Also, one light source is arranged adjacent to four light sources, and the distance between one light source and the four light sources adjacent to it can be approximately the same.

[0069] In addition, according to an embodiment, a plurality of light sources may be arranged so that an approximately equilateral triangle is formed by three adjacent light sources. In this case, one light source may be arranged adjacent to six light sources. Also, the distance between one light source and the six light sources adjacent to it may be approximately the same.

[0070] However, the arrangement of the plurality of light-emitting elements (111) is not limited to the arrangement described above, and the plurality of light-emitting elements (111) can be arranged in various ways so that light is emitted with uniform brightness.

[0071] The light-emitting element (111) may employ a device capable of emitting monochromatic light (light of a specific wavelength, e.g., blue light) or white light (e.g., light mixed with red, green, and blue light) in various directions when power is supplied. For example, the light-emitting element (111) may include a light-emitting diode (LED). The light-emitting diode may be implemented in various sizes and may include, for example, Mini LEDs and / or Micro LEDs.

[0072] The substrate (112) can fix a plurality of light-emitting elements (111) so that the position of the light-emitting elements (111) is not changed. In addition, the substrate (112) can supply power to each light-emitting element (111) for the light-emitting elements (111) to emit light.

[0073] The substrate (112) may include a synthetic resin and / or reinforced glass and / or a printed circuit board (PCB) having a conductive power supply line formed therein to fix a plurality of light-emitting elements (111) and to supply power to the light-emitting elements (111).

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

[0075] A plurality of through holes (120a) are formed in the reflective sheet (120) at positions corresponding to each of the plurality of light-emitting elements (111) of the light source module (110). Additionally, the light-emitting elements (111) of the light source module (110) can pass through the through holes (120a) and protrude forward from the reflective sheet (120).

[0076] For example, during the assembly process of the reflective sheet (120) and the light source module (110), a plurality of light-emitting elements (111) of the light source module (110) are inserted into a plurality of through holes (120a) formed in the reflective sheet (120). As a result, the substrate (112) of the light source module (110) is located at the rear of the reflective sheet (120), but the plurality of light-emitting elements (111) of the light source module (110) can be located at the front of the reflective sheet (120).

[0077] Accordingly, a plurality of light-emitting elements (111) can emit light in front of the reflective sheet (120).

[0078] A plurality of light-emitting elements (111) can emit light in various directions in front of the reflective sheet (120). The light can be emitted from the light-emitting elements (111) toward the diffuser plate (130) as well as from the light-emitting elements (111) toward the reflective sheet (120), and the reflective sheet (120) can reflect the light emitted toward the reflective sheet (120) toward the diffuser plate (130).

[0079] Light emitted from the light-emitting element (111) passes through various objects such as a diffuser plate (130) and an optical sheet (140). When the light passes through the diffuser plate (130) and the optical sheet (140), some of the incident light is reflected from the surface of the diffuser plate (130) and the optical sheet (140). A reflective sheet (120) can reflect the light reflected by the diffuser plate (130) and the optical sheet (140).

[0080] A diffuser plate (130) can be provided in front of the light source module (110) and the reflective sheet (120) and can evenly disperse light emitted from the light-emitting element (111) of the light source module (110).

[0081] As previously explained, a plurality of light-emitting elements (111) are located at various points on the rear of the backlight unit (100). Although the plurality of light-emitting elements (111) are arranged at equal intervals on the rear of the backlight unit (100), non-uniformity in brightness may occur depending on the position of the plurality of light-emitting elements (111).

[0082] The diffuser plate (130) can diffuse light emitted from a plurality of light-emitting elements (111) within the diffuser plate (130) to eliminate non-uniformity in brightness caused by a plurality of light-emitting elements (111). In other words, the diffuser plate (130) can uniformly emit non-uniform light from a plurality of light-emitting elements (111) to the front.

[0083] The optical sheet (140) may include various sheets to improve brightness and uniformity of brightness. For example, the optical sheet (140) may include a diffusion sheet (141), a first prism sheet (142), a second prism sheet (143), a reflective polarizing sheet (144), etc.

[0084] The diffusion sheet (141) diffuses light for uniform brightness. Light emitted from the light-emitting element (111) is diffused by the diffusion plate (130) and can be diffused again by the diffusion sheet (141) included in the optical sheet (140).

[0085] The first and second prism sheets (142, 143) can increase brightness by concentrating light diffused by the diffusion sheet (141). The first and second prism sheets (142, 143) include a prism pattern in the shape of a triangular prism, and a plurality of these prism patterns are arranged adjacently to form a plurality of band shapes.

[0086] A reflective polarizing sheet (144) is a type of polarizing film that can transmit some of the incident light and reflect others to improve brightness. For example, it can transmit polarization in the same direction as a predetermined polarization direction of the reflective polarizing sheet (144) and reflect polarization in a direction different from the polarization direction of the reflective polarizing sheet (144). In addition, the light reflected by the reflective polarizing sheet (144) is recycled inside the backlight unit (100), and the brightness of the display device (10) can be improved through this light recycling.

[0087] The optical sheet (140) is not limited to the sheet or film shown in FIG. 4 and may include a wider variety of sheets or films, such as a protective sheet.

[0088] The backlight unit (100) includes a plurality of light-emitting elements (111) and can output surface light by diffusing light emitted from a plurality of light sources (111). The liquid crystal panel (20) includes a plurality of pixels and can control the plurality of pixels so that each of the plurality of pixels allows light to pass through or blocks light. An image can be formed by the light passing through each of the plurality of pixels.

[0089] At this time, the display device (10) can perform local dimming by varying the brightness of light in different areas of the backlight unit (100) in conjunction with the output image so as to improve power consumption while increasing the contrast ratio.

[0090] For example, the display device (10) may reduce the brightness of the light of the light-emitting element (111) of the backlight unit (100) corresponding to the dark part of the image to make the dark part of the image darker, and may increase the brightness of the light-emitting element (111) of the backlight unit (100) corresponding to the bright part of the image to make the bright part of the image brighter. By doing so, the contrast ratio or brightness ratio of the image may be improved.

[0091] The display device (10) divides the backlight unit (100) into multiple blocks and independently controls the current for each block according to the input image. The image transmission of the display device (10) is carried out by a method of local dimming driving per frame, and the driving of the current is controlled according to the number of blocks of the light-emitting element (111) divided within the backlight unit (100).

[0092] As a result, the display device (10) can effectively improve the contrast ratio by lowering the supply current to the dimming block in the dark area of ​​the input image and increasing the supply current to the dimming block in the bright area of ​​the input image.

[0093] For local dimming, a plurality of light-emitting elements (111) included in the backlight unit (100) may be divided into a plurality of dimming blocks (200). For example, as shown in FIG. 5, the plurality of dimming blocks (200) may be composed of 5 rows and 12 columns, for a total of 60. As another example, the plurality of dimming blocks (200) may be composed of 5 rows and 4 columns, for a total of 20. However, the number of dimming blocks (200) is not limited to the above examples.

[0094] Referring to FIG. 5, each of the plurality of dimming blocks (200) may include at least one light-emitting element (111). The backlight unit (100) may supply the same driving current to the light-emitting elements (111) belonging to the same dimming block (200), and the light-emitting elements (111) belonging to the same dimming block (200) may emit light of the same brightness.

[0095] Additionally, the backlight unit (100) can supply different driving currents to light-emitting elements (111) belonging to different dimming blocks (200) according to dimming data, and the light-emitting elements (111) belonging to different dimming blocks (200) can emit light of different brightness.

[0096] Each of the plurality of dimming blocks (200) may include N*M light sources arranged in the form of an N*M matrix (N and M are natural numbers), for example. An N*M matrix means a matrix having N rows and M columns.

[0097] Since each light-emitting element (111) includes a light-emitting diode, each of the plurality of dimming blocks (200) may include N*M light-emitting diodes. That is, each of the plurality of dimming blocks (200) may include a predetermined number of light-emitting elements (111).

[0098] A plurality of dimming blocks (200) can be placed on the substrate (112). That is, N*M light-emitting diodes can be placed on the substrate (112).

[0099] FIG. 6 is a diagram showing a control block diagram of a display device according to one embodiment, and FIG. 7 illustrates an example of a display device according to one embodiment converting dimming data from image data.

[0100] Referring to FIG. 6, the display device (10) may include a content receiving unit (80), an image processing unit (90), a panel driver (30), a liquid crystal panel (20), and a backlight unit (100). At this time, the backlight unit (100) may include a dimming driver (250) that performs local dimming and a driving element (300) that drives a light-emitting element (111). Such a driving element (300) may be placed on the upper surface of the substrate (112) or on the lower surface of the substrate (112).

[0101] The content receiving unit (80) may include a receiving terminal (81) and a tuner (82) for receiving content including video signals and / or audio signals from content sources.

[0102] The receiving terminal (81) can receive video and audio signals from content sources through a cable. For example, the receiving terminal (81) may include a component (YPbPr / RGB) terminal, a composite (composite video blanking and sync, CVBS) terminal, an audio terminal, a High Definition Multimedia Interface (HDMI) terminal, a Universal Serial Bus (USB) terminal, etc.

[0103] The tuner (82) receives broadcast signals from a broadcast receiving antenna or a wired cable and can extract broadcast signals of a channel selected by the user among the broadcast signals. For example, the tuner (82) can pass broadcast signals having a frequency corresponding to a channel selected by the user among a plurality of broadcast signals received through a broadcast receiving antenna or a wired cable, and block broadcast signals having other frequencies.

[0104] In this way, the content receiving unit (80) can receive an image including video signals and audio signals from content sources through the receiving terminal (81) and / or tuner (82), and can output the input image received through the receiving terminal (81) and / or tuner (82) to the image processing unit (90).

[0105] The image processing unit (90) may include at least one processor (91) for processing an input image (image data) and a memory (92) for storing / remembering data.

[0106] The memory (92) stores programs and data for processing video signals and / or audio signals, and can temporarily store data generated while processing video signals and / or audio signals.

[0107] The memory (92) may include non-volatile memory such as ROM (Read Only Memory) and flash memory, and volatile memory such as S-RAM (Static Random Access Memory, S-RAM) and D-RAM (Dynamic Random Access Memory).

[0108] At least one processor (91) receives an input image including a video signal and / or an audio signal from a content receiving unit (80), can decode the video signal into image data, and can generate dimming data from the image data. The image data and the dimming data can be output to a panel driver (30) and a dimming driver (250), respectively.

[0109] At least one processor (91) can provide dimming data for local dimming to a backlight unit (100). The dimming data may include information regarding the brightness of each of the plurality of dimming blocks (200). For example, the dimming data may include information regarding the intensity of light output by a light-emitting element (111) included in each of the plurality of dimming blocks (200). That is, the dimming data may include information regarding the magnitude of the current supplied to the light-emitting element (111) included in each of the plurality of dimming blocks (200).

[0110] At least one processor (91) can obtain dimming data from video data decoded from a video signal.

[0111] The processor (91) can convert image data into dimming data in various ways. For example, as shown in FIG. 7, the processor (91) can divide an image (I) based on image data into a plurality of image blocks (IB). The number of the plurality of image blocks (IB) is equal to the number of the plurality of dimming blocks (200), and each of the plurality of image blocks (IB) can correspond to the plurality of dimming blocks (200).

[0112] The processor (91) can obtain the luminance values ​​(L) of the plurality of dimming blocks (200) from the image data of the plurality of image blocks (IB). Additionally, the processor (91) can generate dimming data by combining the luminance values ​​(L) of the plurality of dimming blocks (200).

[0113] For example, the processor (91) can obtain the luminance value (L) of each of the plurality of dimming blocks (200) based on the maximum value among the luminance values ​​of the pixels included in each of the image blocks (IB).

[0114] A single image block includes multiple pixels, and the image data of a single image block may include image data of multiple pixels (e.g., red data, green data, blue data, etc.). The processor (91) can calculate the luminance value of each pixel based on the image data of each pixel.

[0115] The processor (91) can set the maximum value among the luminance values ​​of each pixel included in the image block as the luminance value of the dimming block corresponding to the image block. For example, the processor (91) can set the maximum value among the luminance values ​​of the pixels included in the i-th image block (IB(i)) as the luminance value (L(i)) of the i-th dimming block, and the maximum value among the luminance values ​​of the pixels included in the j-th image block (IB(j)) as the luminance value (L(j)) of the j-th dimming block.

[0116] The processor (91) can generate dimming data by combining the brightness values ​​of a plurality of dimming blocks (200).

[0117] In this way, the image processing unit (90) can decode the video signal obtained by the content receiving unit (80) into image data and generate dimming data from the image data. Additionally, the image processing unit (90) can transmit the image data and dimming data to the liquid crystal panel (20) and the light source device (100), respectively.

[0118] The liquid crystal panel (20) includes a plurality of pixels capable of transmitting or blocking light, and the plurality of pixels are arranged in a matrix form. In other words, the plurality of pixels can be arranged in a plurality of rows and a plurality of columns.

[0119] The panel driver (30) receives image data from the image processing unit (90) and can drive the liquid crystal panel (20) according to the image data. In other words, the panel driver (30) can convert image data (hereinafter referred to as 'digital image data'), which is a digital signal, into an analog image signal, which is an analog voltage signal, and provide the converted analog image signal to the liquid crystal panel (20). According to the analog image signal, the optical properties (e.g., light transmittance) of a plurality of pixels included in the liquid crystal panel (20) can change.

[0120] The panel driver (30) may include, for example, a timing controller, a data driver, a scan driver, etc.

[0121] The timing controller receives image data from the image processing unit (90) and can output the image data and a drive control signal to the data driver and the scan driver. The drive control signal may include a scan control signal and a data control signal, and the scan control signal and the data control signal may be used to control the operation of the scan driver and the operation of the data driver, respectively.

[0122] The scan driver receives a scan control signal from the timing controller and can input-activate one of a plurality of rows in the liquid crystal panel (20) according to the scan control signal. In other words, the scan driver converts the pixels included in one of a row among a plurality of pixels arranged in a plurality of rows and a plurality of columns into a state where they can receive an analog image signal. At this time, pixels other than those input-activated by the scan driver cannot receive an analog image signal.

[0123] The data driver receives image data and a data control signal from the timing controller and can output the image data to the liquid crystal panel (20) according to the data control signal. For example, the data driver can receive digital image data from the timing controller and convert the digital image data into an analog image signal. Additionally, the data driver can provide an analog image signal to pixels included in any row that is input-activated by the scan driver. At this time, the pixels input-activated by the scan driver receive the analog image signal, and the optical properties (e.g., light transmittance) of the input-activated pixels change according to the received analog image signal.

[0124] In this way, the panel driver (30) can drive the liquid crystal panel (20) according to the image data. Accordingly, an image corresponding to the image data can be displayed on the liquid crystal panel (20).

[0125] The light source device (100) includes a plurality of light sources (111) that emit light, and the plurality of light sources (111) are arranged in a mastrick form. In other words, the plurality of light sources (111) can be arranged in a plurality of rows and a plurality of columns. Additionally, the light source device (100) can be divided into a plurality of dimming blocks (200), and each of the plurality of dimming blocks (200) can include at least one light source.

[0126] The dimming driver (250) receives dimming data from the image processing unit (90) and can drive the light source device (100) according to the dimming data. Here, the dimming data may include information regarding the luminance of each of the plurality of dimming blocks (200) or information regarding the brightness of the light sources included in each of the plurality of dimming blocks (200).

[0127] The dimming driver (250) can convert dimming data (hereinafter referred to as 'digital dimming data'), which is a digital signal, into an analog dimming signal, which is an analog voltage signal, and provide the analog dimming signal to the light source device (100). Depending on the analog dimming signal, the intensity of light emitted by the light sources included in each of the plurality of dimming blocks (200) can change.

[0128] In particular, the dimming driver (250) may not directly provide analog dimming signals to all of the multiple dimming blocks (200), but may sequentially provide analog dimming signals to the multiple dimming blocks (200) in an active matrix manner.

[0129] As previously described, a plurality of dimming blocks (200) can be arranged in a mastrick form in the light source device (100). In other words, a plurality of dimming blocks (200) can be arranged in a plurality of rows and a plurality of columns in the light source device (100).

[0130] The dimming driver (250) can sequentially provide analog dimming signals to dimming blocks belonging to each of a plurality of rows or sequentially provide analog dimming signals to dimming blocks belonging to each of a plurality of columns.

[0131] For example, the dimming driver (250) can input-activate dimming blocks belonging to one row of a plurality of dimming blocks (200) and provide an analog dimming signal to the input-activated dimming blocks. Subsequently, the dimming driver (250) can input-activate dimming blocks belonging to another row of a plurality of dimming blocks (200) and provide an analog dimming signal to the input-activated dimming blocks.

[0132] FIG. 8 is a drawing illustrating an example of a light-emitting element included in a backlight unit according to one embodiment, and FIG. 9 is a drawing showing a plurality of local dimming blocks according to one embodiment.

[0133] One light-emitting element (111) may include one group of light-emitting diodes (170). That is, one light-emitting element (111) may include a red light-emitting diode (190R), a green light-emitting diode (190G), and a blue light-emitting diode (190B), as shown in FIG. 8.

[0134] A plurality of light-emitting diode groups (170) can be arranged in a two-dimensional matrix form on the upper surface of the substrate (112). That is, as shown in FIG. 4, as a plurality of light-emitting elements (111) are arranged in rows and columns, a plurality of light-emitting diode groups (170) can be arranged in a two-dimensional matrix form.

[0135] In addition, according to an embodiment, a plurality of light sources may be arranged so that an approximately equilateral triangle is formed by three adjacent light sources. In this case, one light source may be arranged adjacent to six light sources. Also, the distance between one light source and the six light sources adjacent to it may be approximately the same.

[0136] However, the arrangement of the plurality of light-emitting elements (111) is not limited to the arrangement described above, and the plurality of light-emitting elements (111) can be arranged in various ways so that light is emitted with uniform brightness.

[0137] The light-emitting element (111) may employ a device capable of emitting white light (light having multiple peak wavelengths, for example, light mixed with red light, green light, and blue light) in various directions when power is supplied.

[0138] That is, one light-emitting element (111) can emit white light by including a red light-emitting diode (190R), a green light-emitting diode (190G), and a blue light-emitting diode (190B).

[0139] As shown in FIG. 8, each of the plurality of light-emitting elements (111) may include a group of light-emitting diodes (170) and an optical dome (180).

[0140] The thickness of the backlight unit (100) can also be reduced so that the thickness of the display device (10) is reduced. Each of the plurality of light-emitting elements (111) is reduced so that the thickness of the backlight unit (100) is reduced, and the structure is simplified.

[0141] The light-emitting diodes (190R, 190G, 190B; 190) of the light-emitting diode group (170) can be directly attached to the substrate (112) in a Chip On Board (COB) manner. For example, the light-emitting element (111) may include a light-emitting diode (190) in which a light-emitting diode chip or a light-emitting diode die is directly attached to the substrate (112) without separate packaging.

[0142] The light-emitting diode (190) can be manufactured as a flip-chip type. When attaching the light-emitting diode (190), which is a semiconductor device, to the substrate (112), the electrode pattern of the semiconductor device can be fused directly to the substrate (112) without using an intermediate medium such as a metal lead (wire) or a ball grid array (BGA). In this way, as the metal lead (wire) or ball grid array is omitted, the light-emitting device (111) including the flip-chip type light-emitting diode (190) can be miniaturized.

[0143] In the above description, a flip-chip type light-emitting diode (190) that is directly fused to a substrate (112) in a chip-on-board manner has been described, but the light-emitting element (111) is not limited to a flip-chip type light-emitting diode. For example, the light-emitting element (111) may include a package type light-emitting diode.

[0144] The optical dome (180) can cover the group of light-emitting diodes (170). That is, the optical dome (180) can cover the red light-emitting diode (190R), the green light-emitting diode (190G), and the blue light-emitting diode (190B) included in the group of light-emitting diodes (170).

[0145] The optical dome (180) causes the red light, green light, and blue light emitted from the red light-emitting diode (190R), green light-emitting diode (190G), and blue light-emitting diode (190B), respectively, to refract and mix, thereby allowing white light to be emitted.

[0146] In this way, the optical dome (180) emits white light by mixing red light, green light, and blue light, thereby reducing the distance at which the white light is mixed compared to when there is no optical dome (180), and thus reducing the optical distance (OD) for converting a point light source into a surface light source.

[0147] Additionally, the optical dome (180) can prevent or suppress damage to the light-emitting diode (190) caused by external mechanical action and / or damage to the light-emitting diode (190) caused by chemical action.

[0148] The optical dome (180) may have a dome shape, for example, by cutting a sphere with a surface that does not include its center, or a hemispherical shape, by cutting a sphere with a surface that includes its center. The vertical cross-section of the optical dome (180) may be, for example, arc-shaped or semicircular.

[0149] The optical dome (180) may be composed of silicone or epoxy resin. For example, molten silicone or epoxy resin may be discharged onto a light-emitting diode (190) through a nozzle, and then the discharged silicone or epoxy resin may be cured to form the optical dome (180).

[0150] The optical dome (180) may be optically transparent or translucent. Light emitted from the light-emitting diode (190) may pass through the optical dome (180) and be emitted to the outside.

[0151] At this time, the dome-shaped optical dome (180) can refract light like a lens. For example, light emitted from a light-emitting diode (190) can be dispersed by being refracted by the optical dome (180).

[0152] Thus, the optical dome (180) can not only protect the light-emitting diode (190) from external mechanical and / or chemical or electrical action, but also disperse the light emitted from the light-emitting diode (190).

[0153] In the above description, an optical dome (180) in the form of a silicon dome has been described, but the light-emitting element (111) is not limited to including the optical dome (180). For example, the light-emitting element (111) may include a lens for dispersing light emitted from a light-emitting diode.

[0154] As described above, for local dimming, a plurality of light-emitting elements (111) included in the backlight unit (100) can be divided into a plurality of dimming blocks (200).

[0155] Accordingly, as shown in FIG. 9, four light-emitting elements (111) including a red light-emitting diode (190R), a green light-emitting diode (190G), and a blue light-emitting diode (190B) form a single dimming block (200), and such a plurality of dimming blocks (200) can be arranged in a two-dimensional matrix form. A single dimming block (200) may include a variety of light-emitting elements (111).

[0156] Thus, the present invention allows the light-emitting element (111) to include a red light-emitting diode (190R), a green light-emitting diode (190G), and a blue light-emitting diode (190B), thereby having higher color purity and contrast ratio than local dimming using a single light, and enabling higher image quality.

[0157] FIG. 10 illustrates the arrangement of a dimming driver, a driving element, and a light-emitting element included in a display device according to one embodiment.

[0158] A plurality of light sources each include a light-emitting diode and can be divided into a plurality of dimming blocks (200). A plurality of light sources belonging to the same dimming block can form a group.

[0159] A plurality of driving elements (300) receive an analog dimming signal from a dimming driver (250) and can supply driving current to a plurality of light sources (111) according to the received analog dimming signal.

[0160] Each of these multiple driving elements (300) can supply driving current to a plurality of light sources (111) included in at least two dimming blocks (200) as well as one dimming block (200).

[0161] As illustrated in FIG. 10, a plurality of light sources belonging to a single dimming block may receive current from the same driving element. For example, a plurality of light sources belonging to a first dimming block (210) may receive driving current from a first driving element (310). A plurality of light sources belonging to a second dimming block (220) may receive driving current from a second driving element (320). A plurality of light sources belonging to a third dimming block (230) may receive driving current from a third driving element (330). A plurality of light sources belonging to a fourth dimming block (240) may receive driving current from a fourth driving element (340). In the same way, a plurality of light sources belonging to an nth dimming block may receive driving current from the nth driving element.

[0162] As a result, multiple light sources belonging to a single dimming block can be supplied with the same amount of driving current. In addition, multiple light sources belonging to a single dimming block can emit light of the same intensity.

[0163] In addition, in the case of the present invention, a plurality of light-emitting elements (111) belonging to a single dimming block (200) may include a red light-emitting diode (190R), a green light-emitting diode (190G), and a blue light-emitting diode (190B) as described above, and in this case, light-emitting diodes of the same color may receive current from the driving element through the same current supply line.

[0164] That is, each of the plurality of driving elements may include a plurality of current supply lines for supplying driving current, and each of these current supply lines may be arranged to supply driving current to LEDs of the same color.

[0165] That is, as shown in Fig. 10, a single current supply line from the driving element can be arranged so that only red LEDs are connected to each other, only green LEDs are connected to each other, or only blue LEDs are connected to each other.

[0166] The driving elements (300) receive an analog dimming signal from the dimming driver (250) while input-activated by the dimming driver (250) and can store the received analog dimming signal. Additionally, while input-deactivated, the plurality of driving elements (300) can supply a driving current corresponding to the stored analog dimming signal to the plurality of light sources.

[0167] A plurality of scan lines (S1, S2) for providing scan signals from a dimming driver (250) to a plurality of driving elements (300) and a plurality of data lines (D1, D2) for providing analog dimming signals from a dimming driver (250) to a plurality of driving elements (300) are provided.

[0168] Multiple dimming blocks (200) may be arranged in multiple rows and multiple columns. Driving elements that supply driving current to light sources of dimming blocks belonging to the same row may share the same scan line. For example, a first driving element (310) and a second driving element (320) may share a first scan line (S1), and a third driving element (330) and a fourth driving element (340) may share a second scan line (S2).

[0169] Additionally, driving elements that supply driving current to light sources of dimming blocks belonging to the same column may share the same data line. For example, the first driving element (310) and the third driving element (330) may share the first data line (D1), and the second driving element (320) and the fourth driving element (340) may share the second data line (D2).

[0170] A plurality of driving elements (300) are input-activated by a scan signal of a dimming driver (250) and can receive an analog dimming signal of the dimming driver (250).

[0171] For example, while the dimming driver (250) outputs a scan signal through the first scan line (S1), the first driving element (310) and the second driving element (320) can receive an analog dimming signal through the first data line (D1) and the second data line (D2), respectively. On the other hand, the third driving element (330) and the fourth driving element (340) cannot receive an analog dimming signal.

[0172] Additionally, while the dimming driver (250) outputs a scan signal through the second scan line (S2), the third driving element (330) and the fourth driving element (340) can receive an analog dimming signal through the first data line (D1) and the second data line (D2), respectively. On the other hand, the first driving element (310) and the second driving element (320) cannot receive an analog dimming signal.

[0173] When a plurality of driving elements (300) receive an analog dimming signal, they store the received analog dimming signal and supply driving current to a plurality of light sources according to the stored analog dimming signal.

[0174] For example, even while the dimming driver (250) outputs a scan signal through the first scan line (S1), the third driving element (330) and the fourth driving element (340) can supply driving current to a plurality of light sources included in the third dimming block (230) and the fourth dimming block (240).

[0175] Additionally, while the dimming driver (250) outputs a scan signal through the second scan line (S2), the first driving element (310) and the second driving element (320) can supply driving current to a plurality of light sources included in the first dimming block (210) and the second dimming block (220).

[0176] By driving in this active matrix manner, a plurality of driving elements (300) can sequentially receive analog dimming signals from a dimming driver (250), and can supply driving current to a plurality of light sources even during an input-deactivated state when they do not receive analog dimming signals from the dimming driver (250).

[0177] In addition, by driving in an active matrix manner, the number of pins of the dimming driver (250) for providing analog dimming signals to multiple dimming blocks (200) is reduced. In addition, the number of signal lines for providing analog dimming signals from the dimming driver (250) to multiple dimming blocks (200) is reduced. Accordingly, the number of dimming blocks can be increased without limiting the number of pins of the dimming driver (250).

[0178] The structure and connection relationships of a local dimming block including red, green, and blue LEDs were described above. Below, the division of each of these LEDs into multiple cells will be explained.

[0179] FIG. 11 is a diagram showing that each light-emitting element is divided into a plurality of cells according to one embodiment, FIG. 12 is a diagram for explaining the respective cell voltage of each light-emitting element according to one embodiment, and FIG. 13 is a diagram showing the connection relationship of each plurality of cells of each light-emitting element according to one embodiment.

[0180] When implementing a local dimming system in an LED backlight based on Red / Green / Blue LEDs, a common block voltage can be used, or the block voltages of Red / Green / Blue can be separated. If driven using a common block voltage, the block voltage for each color LED is different, which may reduce luminous efficiency.

[0181] Accordingly, the red LED (190R), green LED (190G), and blue LED (190B) included in each of the plurality of dimming blocks (200) of the display device (10) of the present invention can each be divided into a different number of LED cells.

[0182] For example, the blue LED (190B) can be divided into two LED cells (190B-1, 190B-2), the green LED (190G) can be divided into three LED cells (190G-1, 190G-2, 190G-3), and the red LED (190R) can be divided into four LED cells (190R-1, 190R-2, 190R-3, 190R-4).

[0183] Since the blue LED (190B) has the highest cell voltage, the green LED (190G) has the second highest cell voltage, and the red LED (190R) has the lowest cell voltage, the blue LED (190B) can be divided into the lowest number of LED cells and the red LED (190R) can be divided into the highest number of LED cells so that the block voltages of each color LED are similar.

[0184] To this end, the number of LED cells of the red LED (190R) can be divided into more than the number of LED cells of the green LED (190G), and the number of LED cells of the green LED (190G) can be divided into more than the number of LED cells of the blue LED (190B).

[0185] Additionally, the number of LED cells of the red LED (190R) can be divided into fewer cells than the sum of the number of LED cells of the green LED (190G) and the number of LED cells of the blue LED (190B).

[0186] That is, the red LED (190R) with the lowest cell voltage can be divided into the largest number of LED cells, such that the number is less than the sum of the LED cells of the green LED (190G) and the blue LED (190B).

[0187] For example, the blue LED (190B) can be divided into two LED cells (190B-1, 190B-2), the green LED (190G) can be divided into three LED cells (190G-1, 190G-2, 190G-3), and the red LED (190R) can be divided into four LED cells (190R-1, 190R-2, 190R-3, 190R-4). The number of divided LED cells for each of these colors is merely an example, and they can be divided into various numbers of LED cells to make the block voltages similar. Even if the Red / Green / Blue block voltages are separated, the design complexity of the power assembly (60) can be reduced by making the Red / Green / Blue block voltages as similar as possible.

[0188] As shown in FIG. 12, the cell voltage of the blue LED (190B) may be 2.75 [V], the cell voltage of the green LED (190G) may be 2.5 [V], and the cell voltage of the red LED (190R) may be 2 [V].

[0189] Each divided LED cell can be connected in series with each other through an internal bridge. Accordingly, as shown in FIG. 13 (a), the blue LED (190B) can have a block voltage of 5.5 [V] as it is divided into two LED cells each having a cell voltage of 2.75 [V]. Additionally, as shown in FIG. 13 (b), the green LED (190G) can have a block voltage of 7.5 [V] as it is divided into three LED cells each having a cell voltage of 2.5 [V], and as shown in FIG. 13 (c), the red LED (190R) can have a block voltage of 8 [V] as it is divided into four LED cells each having a cell voltage of 2 [V].

[0190] Since different cell voltages can be used depending on the characteristics of each color LED, driving efficiency can be increased by dividing the LEDs into different numbers of LED cells for each color and making the block voltages similar.

[0191] FIGS. 14 and 15 are drawings for explaining the connection wiring of a driving element and each light-emitting element according to one embodiment.

[0192] As described above, a plurality of light-emitting elements (111) belonging to a single dimming block (200) may include a red light-emitting diode (190R), a green light-emitting diode (190G), and a blue light-emitting diode (190B) as described above, and in this case, light-emitting diodes of the same color may receive current from the driving element through the same current supply line.

[0193] That is, each of the plurality of driving elements may include a plurality of current supply lines for supplying driving current, and each of these current supply lines may be arranged to supply driving current to LEDs of the same color.

[0194] That is, as shown in FIGS. 10, 14, and 15, a single current supply line from the driving element can be arranged so that only red LEDs are connected to each other, only green LEDs are connected to each other, or only blue LEDs are connected to each other.

[0195] At this time, since each color LED is divided into at least two LED cells, the current flowing to each LED cell can be reduced. Accordingly, the LED cells are driven with a relatively low current, thereby further increasing the driving efficiency.

[0196] A display device according to one embodiment includes a liquid crystal panel; a backlight unit that provides light to the liquid crystal panel; wherein the backlight unit includes a substrate; and a plurality of dimming blocks arranged in a plurality of rows and a plurality of columns on the substrate, each including a red LED, a green LED, and a blue LED; wherein the red LED, green LED, and blue LED included in each of the plurality of dimming blocks are each divided into a different number of LED cells, and the divided LED cells can be connected in series with each other.

[0197] According to the present disclosure, by varying the number of LED cells for each color of the local dimming block, the block voltages of each color LED can be made similar to each other, thereby increasing driving efficiency.

[0198] In addition, the current is distributed to each LED cell, allowing the LED cells to operate at a relatively low current, which can increase driving efficiency.

[0199] The number of LED cells of the red LED is greater than the number of LED cells of the green LED, and the number of LED cells of the green LED may be greater than the number of LED cells of the blue LED.

[0200] The number of LED cells of the red LED may be less than the sum of the number of LED cells of the green LED and the number of LED cells of the blue LED.

[0201] The blue LED can be divided into 2 LED cells, the green LED can be divided into 3 LED cells, and the red LED can be divided into 4 LED cells.

[0202] It further includes a plurality of driving elements for driving the plurality of dimming blocks; and each of the plurality of driving elements can supply a driving current to a plurality of light-emitting elements included in at least two dimming blocks.

[0203] Each of the above plurality of driving elements further includes a plurality of current supply lines for supplying driving current; and each of the plurality of current supply lines may be arranged to supply driving current to LEDs of the same color.

[0204] The above driving element may be disposed on the upper or lower surface of the substrate.

[0205] Each of the above plurality of dimming blocks may include a predetermined number of light-emitting elements.

[0206] A backlight unit according to one embodiment comprises a substrate; and a plurality of dimming blocks arranged in a plurality of rows and a plurality of columns on the substrate, each including a red LED, a green LED, and a blue LED, wherein the red LED, green LED, and blue LED included in each of the plurality of dimming blocks are each divided into a different number of LED cells, and the divided LED cells can be connected in series with each other.

[0207] The number of LED cells of the red LED is greater than the number of LED cells of the green LED, and the number of LED cells of the green LED may be greater than the number of LED cells of the blue LED.

[0208] The number of LED cells of the red LED may be less than the sum of the number of LED cells of the green LED and the number of LED cells of the blue LED.

[0209] The blue LED can be divided into 2 LED cells, the green LED can be divided into 3 LED cells, and the red LED can be divided into 4 LED cells.

[0210] It further includes a plurality of driving elements for driving the plurality of dimming blocks; and each of the plurality of driving elements can supply a driving current to a plurality of light-emitting elements included in at least two dimming blocks.

[0211] Each of the above plurality of driving elements further includes a plurality of current supply lines for supplying driving current; and each of the plurality of current supply lines may be arranged to supply driving current to LEDs of the same color.

[0212] The above driving element may be disposed on the upper or lower surface of the substrate.

[0213] Each of the above plurality of dimming blocks may include a predetermined number of light-emitting elements.

[0214] According to the disclosed invention, by varying the number of LED cells for each color of the local dimming block, the block voltages of each color LED can be made similar to each other, thereby increasing driving efficiency.

[0215] In addition, the current is distributed to each LED cell, allowing the LED cells to operate at a relatively low current, which can increase driving efficiency.

[0216] Meanwhile, the disclosed embodiments may be implemented in the form of a recording medium that stores instructions executable by a computer. The instructions may be stored in the form of program code and, when executed by a processor, may generate a program module to perform the operation of the disclosed embodiments. The recording medium may be implemented as a computer-readable recording medium.

[0217] Computer-readable recording media include all types of recording media that store instructions that can be decoded by a computer. Examples include ROM (Read Only Memory), RAM (Random Access Memory), magnetic tape, magnetic disk, flash memory, optical data storage devices, etc.

[0218] As described above, the disclosed embodiments have been explained with reference to the attached drawings. Those skilled in the art will understand that the present invention may be practiced in forms different from the disclosed embodiments without changing the technical spirit or essential features of the invention. The disclosed embodiments are illustrative and should not be interpreted restrictively.

Claims

1. Liquid crystal panel; A backlight unit that provides light to the liquid crystal panel; is included, The above backlight unit is, Substrate; A plurality of light-emitting elements, each including a red LED, a green LED, and a blue LED; and A display device in which the red LED, green LED, and blue LED included in each of the plurality of light-emitting elements are each divided into a different number of LED cells, and the divided LED cells are connected in series with each other.

2. In Paragraph 1, The number of LED cells of the above red LED is greater than or equal to the number of LED cells of the above green LED, and A display device in which the number of LED cells of the green LED is greater than the number of LED cells of the blue LED.

3. In Paragraph 2, The number of LED cells of the above red LED is, A display device having fewer LED cells than the sum of the number of LED cells of the green LED and the number of LED cells of the blue LED.

4. In Paragraph 3, The above blue LED is divided into two LED cells, and The above green LED is divided into 3 LED cells, and The above red LED is a display device divided into four LED cells.

5. In Paragraph 1, A plurality of dimming blocks arranged in a plurality of rows and a plurality of columns on the substrate, each including a plurality of light-emitting elements; and It further includes a plurality of driving elements for driving the plurality of dimming blocks mentioned above, and Each of the above plurality of driving elements is a display device that supplies driving current to a plurality of light-emitting elements included in at least two dimming blocks.

6. In Paragraph 5, Each of the above plurality of driving elements further includes a plurality of current supply lines for supplying driving current, and Each of the above plurality of current supply lines is, A display device positioned to supply driving current to LEDs of the same color.

7. In Paragraph 5, The above driving element is, A display device disposed on the upper or lower surface of the above substrate 8. In Paragraph 5, Each of the above plurality of dimming blocks is, A display device comprising a predetermined number of light-emitting elements.

9. Substrate; A plurality of light-emitting elements, each including a red LED, a green LED, and a blue LED; and A backlight unit in which the red LED, green LED, and blue LED included in each of the plurality of light-emitting elements are each divided into a different number of LED cells, and the divided LED cells are connected in series.

10. In Paragraph 9, The number of LED cells of the above red LED is greater than or equal to the number of LED cells of the above green LED, and A backlight unit in which the number of LED cells of the green LED is greater than the number of LED cells of the blue LED.

11. In Paragraph 10, The number of LED cells of the above red LED is, A backlight unit having fewer LED cells than the sum of the number of LED cells of the green LED and the number of LED cells of the blue LED.

12. In Paragraph 11, The above blue LED is divided into two LED cells, and The above green LED is divided into 3 LED cells, and The above red LED is a backlight unit divided into 4 LED cells.

13. In Paragraph 9, A plurality of dimming blocks arranged in a plurality of rows and a plurality of columns on the substrate, each including a plurality of light-emitting elements; and It further includes a plurality of driving elements for driving the plurality of dimming blocks mentioned above, and Each of the above plurality of driving elements is a backlight unit that supplies driving current to a plurality of light-emitting elements included in at least two dimming blocks.

14. In Paragraph 13, Each of the above plurality of driving elements further includes a plurality of current supply lines for supplying driving current, and Each of the above plurality of current supply lines is, A backlight unit positioned to supply driving current to LEDs of the same color.

15. In Paragraph 13, The above driving element is, A backlight unit disposed on the upper or lower surface of the above substrate.

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