Patent Publication Number: US-9418601-B2

Title: Display device with luminance boosting unit

Description:
This application claims priority to Korean Patent Application No. 10-2014-0032228, filed on Mar. 19, 2014, and all the benefits accruing therefrom under 35 U.S.C. §119, the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Field 
     Exemplary embodiments of the invention relate to a display device. 
     2. Description of the Related Art 
     As part of the effort to address the disadvantages of cathode ray tubes (“CRTs”), flat panel displays have been developed. Examples of the flat panel displays include liquid crystal displays (“LCDs”), organic light-emitting diode (“OLED”) displays, and plasma display panels (“PDPs”). 
     In the meantime, an LCD, which is a type of flat panel display, includes an LCD panel, which displays an image by using the optical transmittance of liquid crystal molecules, and a backlight assembly, which is disposed below the liquid crystal panel and provides light to the LCD panel. 
     The LCD panel includes an array substrate having plurality of pixel electrodes and a plurality of thin-film transistors (“TFTs”) electrically connected to the plurality of pixel electrodes, a color filter substrate having a common electrode and a plurality of color filters, and a liquid crystal layer interposed between the array substrate and the color filter substrate. 
     The alignment of liquid crystal molecules in the liquid crystal layer varies in response to an electric field being formed between the plurality of pixel electrodes and the common electrode, and as a result, the transmissivity of light through the liquid crystal layer varies accordingly. When the transmissivity of light through the liquid crystal layer is maximized, the LCD panel may realize a high-luminance white image. When the transmissivity of light through the liquid crystal layer is minimized, the LCD panel may realize a low-luminance black image. 
     SUMMARY 
     It is generally difficult to uniformly align liquid crystal molecules in a liquid crystal layer in one direction, and a failure in the uniform alignment of the liquid crystal molecules in the liquid crystal layer may result in a decrease in the contrast ratio (“CR”) of an image displayed on the liquid crystal display (“LCD”) panel. 
     Exemplary embodiments of the invention provide improving the quality of images displayed by a display device having red pixels, green pixels and blue pixels. 
     However, exemplary embodiments of the invention are not restricted to those set forth herein. The above and other exemplary embodiments of the invention will become more apparent to one of ordinary skill in the art to which the invention pertains by referencing the detailed description of the invention given below. 
     According to an exemplary embodiment of the invention, there is provided a display device. The display device comprises a display panel configured to display an image corresponding to image data input thereto and be divided into a plurality of display blocks, a backlight unit configured to supply light to the display panel and including a light guide panel and a main light source module which supplies light to the light guide panel and a luminance boosting unit configured to supply boosted light to the plurality of display blocks based on the image data and including a plurality of light source modules arranged to correspond to the plurality of display blocks, respectively. 
     According to another exemplary embodiment of the invention, there is provided a display device. The display device comprises a display panel configured to display an image corresponding to image data input thereto and be divided into a plurality of display blocks, a backlight unit configured to supply light to the display panel and including a light guide panel and a main light source module which supplies light to the light guide panel and a luminance boosting unit configured to supply boosted light to the plurality of display blocks based on the image data and including a light source module, which emits light, and a plurality of micromirrors, which reflect light emitted from the light source module and thus transmit the light to the plurality of display blocks. 
     According to the invention, it is possible to improve the quality of images displayed by a display device having red pixels, green pixels and blue pixels. 
     Other features and exemplary embodiments will be apparent from the following detailed description, the drawings, and the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features and advantages of the invention will become more apparent by describing in detailed exemplary embodiments thereof with reference to the accompanying drawings, in which: 
         FIG. 1A  is a block diagram and  FIG. 1B  is an enlarged view of an exemplary embodiment of a display device according to the invention. 
         FIG. 2  is a block diagram of a luminance boosting unit controller illustrated in  FIG. 1A . 
         FIG. 3  is a schematic cross-sectional view of the display device illustrated in  FIG. 1A . 
         FIG. 4  is a plan view of a light source module illustrated in  FIG. 3 . 
         FIG. 5  is a cross-sectional view of the light source module illustrated in  FIG. 4  taken along line I-I. 
         FIG. 6  is a schematic cross-sectional view of another exemplary embodiment of a display device according to the invention. 
         FIG. 7  is a plan view of a light source module illustrated in  FIG. 6 . 
         FIG. 8  is a schematic cross-sectional view of another exemplary embodiment of a display device according to the invention. 
         FIG. 9  is an enlarged perspective view of a light source module illustrated in  FIG. 8 . 
         FIG. 10A  is a block diagram and  FIG. 10B  is an enlarged view of another exemplary embodiment of a display device according to the invention. 
         FIG. 11  is a block diagram of a luminance boosting unit controller illustrated in  FIG. 10A . 
         FIG. 12  is a block diagram of another exemplary embodiment of a display device according to the invention. 
         FIG. 13  is a schematic diagram illustrating the operation of the luminance boosting unit controller illustrated in  FIG. 10A . 
     
    
    
     DETAILED DESCRIPTION 
     Advantages and features of the invention and methods of accomplishing the same may be understood more readily by reference to the following detailed description of exemplary embodiments and the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as being limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this invention will be thorough and complete and will fully convey the concept of the invention to those skilled in the art, and the invention will only be defined by the appended claims. Like numbers refer to like elements throughout. In the drawings, sizes and relative sizes of layers and regions may be exaggerated for clarity. 
     It will be understood that when an element or layer is referred to as being “on” another element or layer, it can be directly on the other element or layer or intervening elements or layers may be present. 
     Spatially relative terms, such as “below”, “beneath”, “lower”, “above”, “upper”, and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the figures. Like reference numerals refer to like elements throughout the specification. 
     Embodiments of the invention are described herein with reference to plan and cross-section illustrations that are schematic illustrations of idealized embodiments of the invention. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments of the invention should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of the invention. 
     It will be understood that, although the terms first, second, third, 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. Thus, a first element discussed below could be termed a second element without departing from the teachings of the invention. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms, including “at least one,” unless the content clearly indicates otherwise. “Or” means “and/or.” As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof. 
     “About” or “approximately” as used herein is inclusive of the stated value and means within an acceptable range of deviation for the particular value as determined by one of ordinary skill in the art, considering the measurement in question and the error associated with measurement of the particular quantity (i.e., the limitations of the measurement system). The term, “about” can mean within one or more standard deviations, or within ±30%, 20%, 10%, 5% of the stated value, for example. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the invention, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     Hereinafter, embodiments of the invention will be described with reference to the attached drawings. 
       FIG. 1A  is a block diagram and  FIG. 1B  is an enlarged view of a display device according to an exemplary embodiment of the invention, and  FIG. 2  is a block diagram of a luminance boosting unit controller illustrated in  FIG. 1A . 
     Referring to  FIGS. 1A and 1B , a display device  10  may include a display panel  100  which displays an image, a backlight unit  200  which supplies light to the display panel  100 , a luminance boosting unit  300  which supplies boosted light to the display panel  100 , and a control unit C which controls the general operation of the display device  10 . The control unit C may include a panel controller  190  which controls the driving of the display panel  100 , a backlight unit controller  290  which controls the driving of the backlight unit  200 , and a luminance boosting unit controller  390  which controls the driving of the luminance boosting unit  300 . 
     The display panel  100 , which displays an image corresponding to image data Dat, may include a plurality of data lines DL, a plurality of gate lines GL which intersect the data lines DL, a plurality of pixels, and a gate driver  110  and a data driver  130  which applies a driving signal to the gate lines GL and the data lines DL. In an exemplary embodiment, the pixels may include a plurality of unit pixels such as red pixels P R , green pixels P G  and blue pixels P B , but the invention is not limited thereto. That is, in other exemplary embodiments, the display panel  100  may also include unit pixels of other colors such as white, emerald or cyan, even though not specifically illustrated in the drawings. Each of the unit pixels may include a switching device, e.g., a thin film transistor (“TFT”) (not illustrated), which is connected to one of the gate lines GL and one of the data lines DL, and a liquid crystal capacitor (not illustrated) and a storage capacitor (not illustrated), which are connected to the switching device. The display panel  100  may include a plurality of display blocks DA, and the number of display blocks DA may be m×n (where m and n are natural numbers). In an exemplary embodiment, the number of display blocks DA may be arranged in an m by n matrix. 
     When the image data Dat is input, the panel controller  190  may generate a panel driving signal for driving the display panel  100  based on the image data Dat. The panel driving signal may be transmitted to the gate driver  110  and the data driver  130  of the display panel  100 , and may then be input to each of the pixels of the display panel  100  by the gate driver  110  and the data driver  130 . In an exemplary embodiment, the panel driving signal may be input in units of frames or fields in synchronization with the frame period or field period of the image data Dat, but the invention is not limited thereto. 
     The backlight unit  200 , which supplies light to the display panel  100 , may include a light guide panel (not illustrated) which changes the path of light incident thereupon so that the incident light travels toward the display panel  100  and a main light source module (not illustrated) which supplies light to the light guide panel. 
     The backlight unit controller  290  may control the driving of the backlight unit  200  based on the image data Dat. More specifically, the backlight unit controller  290  may generate a backlight driving signal based on the image data Dat, and may control the turning on or off of the main light source module in accordance with the backlight driving signal. In an exemplary embodiment, the backlight driving signal may be input in synchronization with the input period of the panel driving signal, but the invention is not limited thereto. That is, the backlight driving signal may be input in units of frames or fields in synchronization with the frame period or field period of the image data Dat. 
     The luminance boosting unit  300 , which supplies boosted light to the m×n display blocks DA of the display panel  100 , may include m×n light source blocks LA corresponding to the m×n display blocks DA, respectively. The luminance boosting unit  300  may include a plurality of light source modules  340  which are disposed on a printed circuit board (“PCB”) (not illustrated), and each of the m×n light source blocks LA may include at least one light source module  340 . The light source modules  340  may include a first light source emitting light of a first color, a second light source emitting light of a second color, which is different from the first color, and a third light source emitting light of a third color, which is different from the first color and the second color. In an exemplary embodiment, the first color, the second color and the third color may be red, green and blue, respectively. 
     The luminance boosting unit controller  390  may control the driving of the luminance boosting unit  300  based on the image data Dat. More specifically, the luminance boosting unit controller  390  may control the driving of the light source modules  340  in units of the display blocks DA based on the image data Dat. 
     As illustrated in  FIGS. 1 and 2 , the luminance boosting unit controller  390  may include a data detector  391 , a block determiner  393  and a light source module driver  395 . In an exemplary embodiment, the data detector  391  may detect block image data corresponding to each of the display blocks DA from the image data Dat. In an exemplary embodiment, the block image data may be representative luminance data of an image displayed in each of the display blocks DA, and the representative luminance data may be average luminance data, maximum luminance data or minimum luminance data of the image displayed in each of the display blocks DA. In an alternative exemplary embodiment, the block image data may be gray-scale data or color purity data of the image displayed in each of the display blocks DA. In a non-limiting exemplary embodiment, the image data Dat may be converted into image data of individual colors, for example, red image data, green image data and blue image data, and the block image data may be detected from each of the individual color image data. 
     The block determiner  393  may determine one or more target display blocks DA to which boosted light is to be supplied based on the block image data. In an exemplary embodiment, the block determiner  393  may compare the block image data with predetermined reference data, may determine one or more target display blocks DA based on the results of the comparison, and may generate a light source module driving signal. 
     More specifically, the block determiner  393  may compare the block image data detected by the data detector  391  with the reference data, and may determine one or more display blocks DA corresponding to block image data exceeding the reference data as target display blocks DA, and may generate a light source module driving signal for driving the light source modules  340  of the target display blocks DA. In an exemplary embodiment, the reference data may include data relating to a reference luminance level or color purity level, for example, that can be provided by the display device  10 , and the block image data may include luminance data or color purity data of each of the display blocks DA. In an exemplary embodiment, in a case in which an image displayed in a particular display block DA has a luminance or color purity level that cannot be displayed by the display device  10 , the block determiner  393  may determine the particular display block DA as a target display block DA to which boosted light is to be supplied, but the invention is not limited thereto. That is, in other exemplary embodiments, the block determiner  393  may determine one or more target display blocks DA in various manners, other than that set forth herein. 
     The light source module driver  395  may drive the light source modules  340  in accordance with the light source module driving signal applied thereto by the block determiner  393 , and as a result, the light source modules  340  may be driven individually so as to selectively supply boosted light to the display blocks DA of the display panel  100 . 
       FIG. 3  is a schematic cross-sectional view of the display device  10 ,  FIG. 4  is a plan view of a light source module illustrated in  FIG. 3 , and  FIG. 5  is a cross-sectional view of the light source module illustrated in  FIG. 4 . 
     Referring to  FIG. 3 , the backlight unit  200  may be disposed below the display panel  100  including the display blocks DA, and the luminance boosting unit  300  may be disposed below the backlight unit  200 . The luminance boosting unit  300  may include the light source blocks LA, which correspond to the display blocks DA, respectively. 
     The backlight unit  200  may include a light guide panel  230  and a main light source module  250 . 
     The light guide panel  230  may guide light emitted or supplied from the light source module  250 . In an exemplary embodiment, the light guide panel  230  may include a transparent material, and may guide light supplied from the light source module  250  toward the display panel  100 , which is disposed above the light guide panel  230 . Various patterns may be printed on a rear surface of the light guide panel  230  facing the luminance boosting unit  300  for changing the path of light incident upon the light guide panel  230  so that the incident light may travel toward the display panel  100 . In an exemplary embodiment, the light guide panel  230  may include an acrylic material, for example, polymethyl methacrylate (“PMMA”), but the invention is not limited thereto. 
     The main light source module  250  may be disposed on one side of the light guide panel  230 , and may provide light to the display panel  100 . The main light source module  250  may include one or more light sources and a PCB on which the light sources are mounted. In an exemplary embodiment, the light sources may include white light-emitting diodes (“LEDs”), for example, but the invention is not limited thereto. In an alternative exemplary embodiment, the light sources may include red, green and blue LEDs, or may include cold cathode fluorescent lamps (“CCFLs”), for example. 
     The luminance boosting unit  300  may be disposed below the backlight unit  200 . The luminance boosting unit  300  may include a PCB  330  and the light source modules  340 , which are disposed on the PCB  330 . 
     The PCB  330  may support the light source modules  340 , and may transmit a voltage for driving the light source modules  340  to the light source modules  340 . In an exemplary embodiment, for efficient heat dissipation, a metal core PCB may be used as the PCB  330 , but the invention is not limited thereto. 
     The light source modules  340 , which supply boosted light to the display blocks DA, may be disposed in the light source blocks LA, respectively, and the light source blocks LA correspond to the display blocks DA, respectively. As illustrated in  FIGS. 4 and 5 , each of the light source modules  340  may include a first light source  341  emitting light of a first color, a second light source  343  emitting light of a second color, which is different from the first color, and a third light source  345  emitting light of a third color, which is different from the first color and the second color. In an exemplary embodiment, the first color, the second color and the third color may be red, green and blue, respectively, for example. That is, in the illustrated exemplary embodiment, the first light source  341 , the second light source  343  and the third light source  345  may be a red light source, a green light source and a blue light source, respectively. 
     The first light source  341 , the second light source  343  and the third light source  345  may be driven individually by the luminance boosting unit controller  390  of  FIG. 1A , e.g., the light source module driver  395  of the luminance boosting unit controller  390  of  FIG. 2 , and brightnesses of the first light source  341 , the second light source  343  and the third light source  345  may be adjusted individually. In an exemplary embodiment, only the first light source  341  may be driven to emit red light, only the second light source  343  may be driven to emit green light, or only the third light source  345  may be driven to emit blue light. In the exemplary embodiment, the brightnesses of the red light, the green light and the blue light may be adjusted individually. However, the invention is not limited to the exemplary embodiment. That is, two or more of the first light source  341 , the second light source  343  and the third light source  345  may be driven at the same time, and brightnesses of the first light source  341 , the second light source  343  and the third light source  345  may be adjusted individually, thereby emitting a variety of mixed light. 
     In an exemplary embodiment, the first light source  341 , the second light source  343  and the third light source  345  may be laser diodes, for example. In an exemplary embodiment, the first light source  341 , the second light source  343  and the third light source  345  may be a red laser diode, a green laser diode and a blue laser diode, respectively. In a case in which the first light source  341 , the second light source  343  and the third light source  345  are laser diodes, the first light source  341 , the second light source  343  and the third light source  345  may be able to emit light with a narrow radiation angle, and thus improving the color purity or color reproducibility of an image, but the invention is not limited thereto. That is, in other exemplary embodiments, the first light source  341 , the second light source  343  and the third light source  345  may be LEDs, for example. In an exemplary embodiment, the first light source  341 , the second light source  343  and the third light source  345  may be a red LED, a green LED and a blue LED, respectively, for example. 
     Each of the light source modules  340  may also include a light diffuser  347  which diffuses light emitted from the first light source  341 , the second light source  343  and/or the third light source  345 . In an exemplary embodiment, the light diffuser  347  may be a diffusing lens provided to cover the first light source  341 , the second light source  343  and the third light source  345 , for example. 
     The diffusing lens, which is an optical member for diffusing light emitted from the first light source  341 , the second light source  343  and/or the third light source  345  so that the light is emitted outward, may include an inner curved surface  347   a  and an outer curved surface  347   b , which are elliptic surfaces, to effectively scatter light emitted from the first light source  341 , the second light source  343  and/or the third light source  345 . An ellipse is defined as a set of points in a plane such that a sum of a distance from two fixed points remains constant, and the two fixed points are referred to as focal points. In the ellipse, a straight line drawn between the two focal points may be defined as a major axis, and the axis passing through the center of the ellipse and perpendicular to the major axis is defined as a minor axis. 
     The major axis is longer than the minor axis. By rotating the ellipse with reference to the major axis or the minor axis, an elliptic surface may be obtained. 
     In an exemplary embodiment, the inner curved surface  347   a  and the outer curved surface  347   b  of the diffusing lens of the light diffuser  347  may be formed as elliptic surfaces having their major axes perpendicular to each other. In an exemplary embodiment, when the major axis of the inner curved surface  347   a  extends in a vertical direction, the major axis of the outer curved surface  347   b  may extend in a horizontal direction. When the major axes of the inner curved surface  347   a  and the outer curved surface  347   b  perpendicularly intersect each other, the thickness of the light diffuser  347  measured in a vertical direction in a cross-section, i.e., the vertical distance between the inner curved surface  347   a  and the outer curved surface  347   b , may vary from one portion to another portion of the light diffuser  347 . Therefore, differences in the path of light transmitted through the light diffuser  347  may be caused due to the varying thickness of the light diffuser  347 , and as a result, light may be properly diffused by the light diffuser  347 . 
       FIG. 6  is a schematic cross-sectional view of a display device according to another exemplary embodiment of the invention, and  FIG. 7  is a plan view of a light source module illustrated in  FIG. 6 . 
     The display device of  FIG. 6  is the same as the display device of  FIG. 3  except that it includes a luminance boosting unit  300 - 1 , which is different from the luminance boosting unit  300  of  FIG. 3 . Accordingly, the display device of  FIG. 6  will hereinafter be described, focusing mainly on differences from the display device of  FIG. 3 . 
     Referring to  FIGS. 6 and 7 , the luminance boosting unit  300 - 1  may be disposed below a backlight unit  200 , and may include a PCB  330  and a plurality of light source modules  350  disposed on the PCB  330 . 
     The PCB  330  may support the light source modules  350 , and may transmit a voltage for driving the light source modules  350  to the light source modules  350 . In an exemplary embodiment, for efficient heat dissipation, a metal core PCB may be used as the PCB  330 , for example, but the invention is not limited thereto. 
     The light source modules  350 , which supply boosted light to a plurality of display blocks DA, may be disposed in a plurality of light source blocks LA, respectively, and the light source blocks LA may correspond to the display blocks DA, respectively. 
     Each of the light source modules  350  may include a light source  353  and an auxiliary light guide panel  351 , which diffuses light emitted from the light source  353 . The light source  353  may be disposed adjacent to one side of the auxiliary light guide panel  351 . 
     The auxiliary light guide panel  351  may guide light emitted or supplied from the light source  353  toward a display block DA or a part of a light guide panel  230  corresponding to the display block DA. In an exemplary embodiment, the auxiliary light guide panel  351  may include a transparent material, for example. Various patterns may be printed on the rear surface of the auxiliary light guide panel  351  for changing the path of light incident upon the auxiliary light guide panel  351  so that the incident light travels toward the light guide panel  230  or the display block DA. In an exemplary embodiment, the auxiliary light guide panel  351  may include an acrylic material, for example, PMMA, but the invention is not limited thereto. 
     As illustrated in  FIG. 6 , the auxiliary light guide panels  351  of the light source modules  350  may be disposed on a level with one another to not overlap one another. That is, the auxiliary light guide panels  351  of the light source modules  350  may be arranged as tiles. Referring further to  FIG. 7 , a recess may be defined in one side of the auxiliary light guide panel  351 , and the light source  353  may be disposed in the recess. 
     More specifically, the light source  353  may be disposed in the recess in one side of the auxiliary light guide panel  351 . The light source  353  may emit light toward one side of the auxiliary light guide panel  351 . The light source  353  may include a first light source  353   a  emitting light of a first color, a second light source  353   b  emitting light of a second color, which is different from the first color, and a third light source  353   c  emitting light of a third color, which is different from the first color and the second color. In an exemplary embodiment, the first color, the second color and the third color may be red, green and blue, respectively, for example. That is, in the illustrated exemplary embodiment, the first light source  353   a , the second light source  353   b  and the third light source  353   c  may be a red light source, a green light source and a blue light source, respectively, for example. 
     The first light source  353   a , the second light source  353   b  and the third light source  353   c , like the first light source  341 , the second light source  343  and the third light source  345  of  FIG. 4 , may be driven individually by the luminance boosting unit controller  390  of  FIG. 1A , e.g., the light source module driver  395  of the luminance boosting unit controller  390  of  FIG. 2 , and their brightnesses may be adjusted individually. 
     In an exemplary embodiment, the first light source  353   a , the second light source  353   b  and the third light source  353   c  may be laser diodes. In an exemplary embodiment, the first light source  353   a , the second light source  353   b  and the third light source  353   c  may be a red laser diode, a green laser diode and a blue laser diode, respectively, but the invention is not limited thereto. That is, in other exemplary embodiments, the first light source  353   a , the second light source  353   b  and the third light source  353   c  may be LEDs. In an exemplary embodiment, the first light source  353   a , the second light source  353   b  and the third light source  353   c  may be a red LED, a green LED and a blue LED, respectively, for example. 
       FIG. 8  is a schematic cross-sectional view of a display device according to another exemplary embodiment of the invention, and  FIG. 9  is a perspective view of a light source module illustrated in  FIG. 8 . The display device of  FIG. 8  is the same as the display device of  FIG. 3 or 6  except that it includes a luminance boosting unit  300 - 2 , which is different from the luminance boosting unit  300  of  FIG. 3  and the luminance boosting unit  300 - 1  of  FIG. 6 . Accordingly, the display device of  FIG. 8  will hereinafter be described, focusing mainly on differences from the display device of  FIG. 3  and the display device of  FIG. 6 . 
     Referring to  FIGS. 8 and 9 , the luminance boosting unit  300 - 2  may be disposed below a backlight unit  200 , and may include a PCB  330  and a plurality of light source modules  360  disposed on the PCB  330 . 
     The light source modules  360 , which supply boosted light to a plurality of display blocks DA, may be disposed to overlap a plurality of light source blocks LA corresponding to the display blocks DA, respectively. 
     Each of the light source modules  360  may include a light source  363  and an auxiliary light guide panel  361 , which diffuses light emitted from the light source  363 . The light source  363  may be disposed on one side of the auxiliary light guide panel  361 . 
     The light source  363  may include a first light source  363   a  emitting light of a first color, a second light source  363   b  emitting light of a second color, which is different from the first color, and a third light source  363   c  emitting light of a third color, which is different from the first color and the second color. In an exemplary embodiment, the first color, the second color and the third color may be red, green and blue, respectively, for example. That is, in an exemplary embodiment, the first light source  363   a , the second light source  363   b  and the third light source  363   c  may be a red light source, a green light source and a blue light source, respectively, for example. The light source  363  is the same as its counterparts in  FIGS. 3, 6 and 7 , and thus, a detailed description thereof will be omitted. 
     The auxiliary light guide panel  361  may guide light emitted or supplied from the light source  363  toward a display block DA or part of a light guide panel  230  corresponding to the display block DA. The auxiliary light guide panel  361  may include a transparent material. Various patterns may be printed on a rear surface of the auxiliary light guide panel  361  facing the PCB  330  for changing the path of light incident upon the auxiliary light guide panel  361  so that the incident light travels toward the light guide panel  230  or the display block DA, and a reflective sheet  361   f  may be additionally provided, when necessary. In an exemplary embodiment, the auxiliary light guide panel  361  may include an acrylic material, for example, PMMA, but the invention is not limited thereto. 
     As illustrated in  FIG. 8 , the auxiliary light guide panels  361  of the light source modules  360  may be disposed to overlap one another. As illustrated in  FIG. 9 , the auxiliary light guide panel  361  may include an emission portion  361   b  having an emission surface  361   a  through which light is emitted and a light guide portion  361   c  guiding light emitted from the light source  363 . The auxiliary light guide panels  361  of the light source modules  361  may be disposed in such a manner that the emission portions  361   b  of the auxiliary light guide panels  361  of the light source modules  360  correspond to the display blocks DA, respectively. The first light source  363   a , the second light source  363   b  and the third light source  363   c  may be disposed on one side of the corresponding light guide portion  361   c . Referring further to  FIG. 9 , a stepped portion  361   d  may be provided between, and connect, the emission portion  361   b  and the light guide portion  361   c . That is, the thickness of the auxiliary light guide panel  361  at the emission portion  361   b  may differ from the thickness of the auxiliary light guide panel  361  at the light guide portion  361   c . In  FIG. 9 , reference numeral  361   e  denotes the distal side of the auxiliary light guide panel  361  from the light source  363 . The light guide portion  361   c  of an auxiliary light guide panel  361  may overlap the emission portion  361   b  of a neighboring auxiliary light guide panel  361 . The stepped portion  361   d  of an auxiliary light guide panel  361  may face the distal side  361   e  of a neighboring auxiliary light guide panel  361 . According to this type of configuration of the auxiliary light guide panels  361  of the light source modules  360 , it is possible to uniformly supply light from the light sources  363  of the light source modules to the display blocks DA. 
       FIG. 10A  is a block diagram and  FIG. 10B  is an enlarged view of a display device according to another exemplary embodiment of the invention,  FIG. 11  is a block diagram of a luminance boosting unit controller illustrated in  FIG. 10A , and  FIG. 12  is a block diagram of a display device according to another exemplary embodiment of the invention. 
     A display device  20  of  FIGS. 10 to 12  is the same as the display device  10  of  FIGS. 1 and 2  except that it includes a luminance boosting unit  400  and a luminance boosting unit controller  490  that are different from the luminance boosting unit  300  and the luminance boosting unit controller  390 , respectively, of  FIGS. 1 and 2 . Accordingly, the display device  20  will hereinafter be described, focusing mainly on differences from the display device  10 . 
     Referring to  FIGS. 10A and 10B , the display device  20  may include a display panel  100  which displays an image, a backlight unit  200  which supplies light to the display panel  100 , the luminance boosting unit  400  which supplies boosted light to the display panel  100 , and a control unit C which controls the general operation of the display device  20 . The control unit C may include a panel controller  190  which controls the driving of the display panel  100 , a backlight unit controller  290  which controls the driving of the backlight unit  200 , and the luminance boosting unit controller  490  which controls the driving of the luminance boosting unit  400 . 
     The display panel  100 , which displays an image corresponding to image data Dat, may include a plurality of display blocks DA, and the number of display blocks DA may be m×n (where m and n are natural numbers). In an exemplary embodiment, the number of display blocks DA may be arranged in an m by n matrix. 
     The luminance boosting unit  400 , which supplies boosted light to the display blocks DA of the display panel  100 , may include a light source module  410  and a plurality of micromirrors  430 . 
     As illustrated in  FIG. 12 , the light source module  410  may include a first light source  410   a  emitting light of a first color, a second light source  410   b  emitting light of a second color, which is different from the first color, and a third light source  410   c  emitting light of a third color, which is different from the first color and the second color. In an exemplary embodiment, the first color, the second color and the third color may be red, green and blue, respectively, for example. 
     In an exemplary embodiment, the first light source  410   a , the second light source  410   b  and the third light source  410   c  may be laser diodes, for example. In an exemplary embodiment, the first light source  410   a , the second light source  410   b  and the third light source  410   c  may be a red laser diode, a green laser diode and a blue laser diode, respectively, for example. When the first light source  410   a , the second light source  410   b  and the third light source  410   c  are laser diodes, the first light source  410   a , the second light source  410   b  and the third light source  410   c  may be able to emit light with a narrow radiation angle, and thus improving the color purity or color reproducibility of an image, but the invention is not limited thereto. That is, in other exemplary embodiments, the first light source  410   a , the second light source  410   b  and the third light source  410   c  may be LEDs, for example. In an exemplary embodiment, the first light source  410   a , the second light source  410   b  and the third light source  410   c  may be a red LED, a green LED and a blue LED, respectively, for example. 
     The micromirrors  430  may reflect light provided by the light source module  410  so as to transmit the light to the display blocks DA. The number of micromirrors  430  may be the same as the number of display blocks DA. In an exemplary embodiment, when there are m×n display blocks DA, m×n micromirrors  430  may be provided, but the invention is not limited thereto. That is, in other exemplary embodiments, the number of micromirrors  430  may be appropriately determined. 
     In an exemplary embodiment, the micromirrors  430  may be implemented as digital micromirror devices (“DMDs”), for example, which are optical devices widely used in various fields. A DMD chip has on its surface numerous micromirrors arranged in an array. The reflection angle of micromirrors  430  may be adjusted in accordance with a mirror driving signal. 
     The luminance boosting unit controller  490  may control the driving of the luminance boosting unit  400  based on the image data Dat. More specifically, the luminance boosting unit controller  490  may control the driving of the light source module  410  corresponding to the display blocks DA based on the image data Dat. 
     As illustrated in  FIGS. 10 to 12 , the luminance boosting unit controller  490  may include a data detector  491 , a block determiner  493 , a light source module driver  495  and a mirror driver  497 . In an exemplary embodiment, the data detector  491  may detect block image data corresponding to each of the display blocks DA from the image data Dat. In an exemplary embodiment, the block image data may be representative luminance data of an image displayed in each of the display blocks DA, and the representative luminance data may be average luminance data, maximum luminance data or minimum luminance data of the image displayed in each of the display blocks DA, for example. In an alternative exemplary embodiment, the block image data may be gray-scale data or color purity data of the image displayed in each of the display blocks DA, for example. In a non-limiting exemplary embodiment, the image data Dat may be converted into image data of individual colors, for example, red image data, green image data and blue image data, and the block image data may be detected from each of the individual color image data. 
     The block determiner  493  may determine one or more target display blocks DA to which boosted light is to be supplied based on the block image data. In an exemplary embodiment, the block determiner  493  may compare the block image data with predetermined reference data, may determine one or more target display blocks DA based on the results of the comparison, and may generate a light source module driving signal and a mirror driving signal. 
     More specifically, the block determiner  493  may compare the block image data detected by the data detector  491  with the reference data, and may determine one or more display blocks DA corresponding to block image data exceeding the reference data as target display blocks DA, and may generate a mirror driving signal for driving micromirrors  430  corresponding to the target display blocks DA and a light source module driving signal for driving the light source module  410 . In an exemplary embodiment, the reference data may include data relating to a reference luminance level or color purity level that can be provided by the display device  20 , and the block image data may include luminance data or color purity data of each of the display blocks DA, for example. In an exemplary embodiment, in a case in which an image displayed in a particular display block DA has a luminance or color purity level that cannot be provided by the display device  20 , the block determiner  493  may determine the particular display block DA as a target display block DA to which boosted light is to be supplied, but the invention is not limited thereto. That is, in other exemplary embodiments, the block determiner  493  may determine one or more target display blocks DA in various manners, other than that set forth herein. 
     The light source module driver  495  may drive the light source module  410  in accordance with the light source module driving signal applied thereto by the block determiner  493 . The light source module driver  495  may drive the first light source  410   a , the second light source  410   b  and the third light source  410   c  of the light source module  410  individually or sequentially, or may drive two or more of the first light source  410   a , the second light source  410   b  and the third light source  410   c  at the same time. 
     The mirror driver  497  may drive the micromirrors  430  in accordance with the mirror driving signal applied thereto by the block determiner  493 . The mirror driving signal may be synchronized with the light source module driving signal, and the micromirrors  430  may be driven to correspond to the operation of the light source module  410 . That is, to supply red light to a particular display block DA, the light source module driver  495  may drive only the first light source  410   a , which emits red light, and the mirror driver  497  may adjust the reflection angle of a micromirror  430  corresponding to the particular display block DA so that the red light emitted from the first light source  410   a  can be provided to the particular display block DA. 
       FIG. 13  is a schematic cross-sectional view of a display device according to another exemplary embodiment of the invention. 
     Referring to  FIG. 13 , a backlight unit  200  may be disposed below a display panel  100  including a plurality of display blocks DA, and a luminance boosting unit may be disposed below the backlight unit  200  and may include a plurality of light source blocks LA corresponding to the display blocks DA, respectively. 
     The backlight unit  200  may include a light guide panel  230  and a main light source module  250 . The backlight unit  200  is the same as its counterpart of  FIG. 3 , and thus, a detailed description will be omitted. 
     The luminance boosting unit may be disposed below the backlight unit  200 , and may include a light source module  410  and a plurality of micromirrors  430 . 
     The light source module  410 , like its counterpart of  FIGS. 10 and 12 , may include a first light source, a second light source and a third light source, and the first light source, the second light source and the third light source may be laser diodes or LEDs. 
     The micromirrors  430  may include a plurality of micromirrors  431   a  to  431   e  corresponding to the display blocks DA, respectively. To supply boosted light to a particular display block DA, the reflection angle of a micromirror  430  corresponding to the particular display block DA may be adjusted so as to supply light emitted from the light source module  410  to the particular display block DA. 
     The luminance boosting unit may also include an optical member  420  which is provided between the light source module  410  and the micromirrors  430 . The optical member  420  may increase the radiation angle of light to be incident upon the micromirrors  430  from the light source module  410  and thus may improve the uniformity of light to be supplied to the micromirrors  430 . In exemplary embodiments, the optical member  420  may be implemented as a micro lens array (“MLA”) or an array of a plurality of lenticular lenses, but the invention is not limited thereto. 
     The luminance boosting unit includes only one light source module  410  in  FIG. 13 , but the invention is not limited thereto. That is, in other exemplary embodiments, the luminance boosting unit may include more than one light source module  410 , when necessary. 
     According to the exemplary embodiments of the invention, since a luminance boosting unit is provided in a display device, boosted light can be supplied to individual display blocks of a display panel. As a result, the luminance, color purity and color reproducibility of the display panel can be improved in units of the display blocks, and the quality of an image displayed by the display device can be improved. Also, since basic luminance for an image to be displayed is secured by a backlight unit and the luminance boosting unit is selectively driven only when there is the need to supply boosted light to the display panel, the operating efficiency of the display device can be improved. 
     While the invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in provide and detail may be made therein without departing from the spirit and scope of the invention as defined by the following claims. The exemplary embodiments should be considered in a descriptive sense only and not for purposes of limitation.